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Sample records for terbium hydroxides

  1. Elastic properties of terbium

    DEFF Research Database (Denmark)

    Spichkin, Y.I.; Bohr, Jakob; Tishin, A.M.

    1996-01-01

    The temperature dependence of the Young modulus along the crystallographic axes b and c (E(b) and E(c)), and the internal friction of a terbium single crystal have been measured. At 4.2 K, E(b) and E(c) are equal to 38 and 84.5 GPa, respectively. The lattice part of the Young modulus and the Debye...... temperature has been calculated. The origin of the Young modulus anomalies arising at the transition to the magnetically ordered state is discussed....

  2. Aluminum Hydroxide and Magnesium Hydroxide

    Science.gov (United States)

    Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

  3. Aluminum Hydroxide

    Science.gov (United States)

    Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

  4. Magnesium Hydroxide

    Science.gov (United States)

    Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed for ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as needed ...

  5. Critical scattering of neutrons from terbium

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Dietrich, O.W.; Marshall, W.

    1968-01-01

    The inelasticity of the critical scattering of neutrons in terbium has been measured above the Neél temperature at the (0, 0, 2−Q) satellite position. The results show that dynamic slowing down of the fluctuations does occur in a second‐order phase transition in agreement with the general theory...

  6. Semiconductor composition containing iron, dysprosium, and terbium

    Energy Technology Data Exchange (ETDEWEB)

    Pooser, Raphael C.; Lawrie, Benjamin J.; Baddorf, Arthur P.; Malasi, Abhinav; Taz, Humaira; Farah, Annettee E.; Kalyanaraman, Ramakrishnan; Duscher, Gerd Josef Mansfred; Patel, Maulik K.

    2017-09-26

    An amorphous semiconductor composition includes 1 to 70 atomic percent iron, 15 to 65 atomic percent dysprosium, 15 to 35 atomic percent terbium, balance X, wherein X is at least one of an oxidizing element and a reducing element. The composition has an essentially amorphous microstructure, an optical transmittance of at least 50% in at least the visible spectrum and semiconductor electrical properties.

  7. SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

    Science.gov (United States)

    Watt, G.W.

    1958-08-19

    An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

  8. Calcium hydroxide poisoning

    Science.gov (United States)

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  9. Raman spectroscopy study of the doping effect of the encapsulated terbium halogenides on single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kharlamova, M.V.; Kramberger, C.; Mittelberger, A. [University of Vienna, Faculty of Physics, Vienna (Austria)

    2017-04-15

    In the present work, the doping effect of terbium chloride, terbium bromide, and terbium iodide on single-walled carbon nanotubes (SWCNTs) was compared by Raman spectroscopy. A precise investigation of the doping-induced alterations of the Raman modes of the filled SWCNTs was conducted. The shifts of the components of the Raman modes and modification of their profiles allowed concluding that the inserted terbium halogenides have acceptor doping effect on the SWCNTs, and the doping efficiency increases in the line with terbium iodide, terbium bromide, and terbium chloride. (orig.)

  10. Magnetocaloric effect of thin Terbium films

    Science.gov (United States)

    Mello, V. D.; Anselmo, D. H. A. L.; Vasconcelos, M. S.; Almeida, N. S.

    2017-12-01

    We report a theoretical study of the magnetocaloric effect of Terbium (Tb) thin films due to finite size and surface effects in the helimagnetic phase, corresponding to a temperature range from TC=219 K to TN=231 K, for external fields of the order of kOe. For a Tb thin film of 6 monolayers submitted to an applied field (ΔH =30 kOe, ΔH =50 kOe and ΔH = 70 kOe) we report a significative change in adiabatic temperature, ΔT / ΔH , near the Néel temperature, of the order ten times higher than that observed for Tb bulk. On the other hand, for small values of the magnetic field, large thickness effects are found. For external field strength around few kOe, we have found that the thermal caloric efficiency increases remarkably for ultrathin films. For an ultrathin film with 6 monolayers, we have found ΔT / ΔH = 43 K/T while for thicker films, with 20 monolayers, ΔT / ΔH = 22 K/T. Our results suggest that thin films of Tb are a promising material for magnetocaloric effect devices for applications at intermediate temperatures.

  11. Femtosecond XUV spectroscopy of gadolinium and terbium

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Robert; Frietsch, Bjoern; Doebrich, Kristian; Teichmann, Martin; Gahl, Cornelius; Noack, Frank [Max-Born-Institute, Berlin (Germany); Schwarzkopf, Olaf; Wernet, Philippe [Helmholtz-Zentrum fuer Materialien und Energie (BESSY II), Berlin (Germany); Weinelt, Martin [Max-Born-Institute, Berlin (Germany); Fachbereich Physik, Freie Universitaet, Berlin (Germany)

    2011-07-01

    We present recent results of time-resolved IR-pump-XUV-probe experiments on the ultrafast demagnetization of thin films of Gadolinium(0001) and Terbium(0001) on Tungsten(110). The experiments are the first to be done using a newly developed high-order harmonics (HHG) XUV beamline at the MBI. The beamline delivers monochromated XUV pulses of approximately 150 fs duration with a photon energy resolution of up to 150 meV. Following excitation by intense femtosecond infrared (IR) pulses, photoemission with 35 eV photons allows us to directly probe the 4f electrons and their interaction with the valence band, both in the bulk and at the surface, to follow the ultrafast magnetization dynamics in the Lanthanide metals. As signatures of ultrafast demagnetization of the metal by the IR pulse, we see for the first time, rapid strong reduction of the exchange splitting in the valence band. This is followed by a slower demagnetization due to the spin-lattice interaction.

  12. Green fluorescence of terbium ions in lithium fluoroborate glasses ...

    Indian Academy of Sciences (India)

    Glasses; terbium ion; oscillator strengths; fluorescence; lifetimes; fibre lasers. 1. Introduction. Today glasses are most favourable engineering materials for abundant applications due to the wide ability of property altering by compositional modifications. The considerable examination of glass science to achieve required ...

  13. Green fluorescence of terbium ions in lithium fluoroborate glasses ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 39; Issue 3. Green fluorescence of terbium ions in lithium fluoroborate glasses for fibre lasers and display devices. G R DILLIP C MADHUKAR REDDY M RAJESH SHIVANAND CHAURASIA B DEVA PRASAD RAJU S W JOO. Volume 39 Issue 3 June 2016 pp 711-717 ...

  14. Application of magnesium hydroxide and barium hydroxide for the ...

    African Journals Online (AJOL)

    Application of magnesium hydroxide and barium hydroxide for the removal of metals and sulphate from mine water. ... equivalent to the Ba(OH)2 dosage. During CO2-dosing, CaCO3 is precipitated to the saturation level of CaCO3. Keywords: Magnesium hydroxide; barium hydroxide; sulphate removal; water treatment ...

  15. Terahertz Cherenkov radiation from ultrafast magnetization in terbium gallium garnet

    Science.gov (United States)

    Gorelov, S. D.; Mashkovich, E. A.; Tsarev, M. V.; Bakunov, M. I.

    2013-12-01

    We report an experimental observation of terahertz Cherenkov radiation from a moving magnetic moment produced in terbium gallium garnet by a circularly polarized femtosecond laser pulse via the inverse Faraday effect. Contrary to some existing theoretical predictions, the polarity of the observed radiation unambiguously demonstrates the paramagnetic, rather than diamagnetic, nature of the ultrafast inverse Faraday effect. From measurements of the radiation field, the Verdet constant in the subpicosecond regime is ˜3-10 times smaller than its table quasistatic value.

  16. Terbium luminescence in alumina xerogel fabricated in porous anodic alumina matrix under various excitation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gaponenko, N. V., E-mail: nik@nano.bsuir.edu.by [Belarusian State University of Informatics and Radioelectronics (Belarus); Kortov, V. S. [Yeltsin Ural Federal University (Russian Federation); Orekhovskaya, T. I.; Nikolaenko, I. A. [Belarusian State University of Informatics and Radioelectronics (Belarus); Pustovarov, V. A.; Zvonarev, S. V.; Slesarev, A. I. [Yeltsin Ural Federal University (Russian Federation); Prislopski, S. Ya. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus)

    2011-07-15

    Terbium-doped alumina xerogel layers are synthesized by the sol-gel method in pores of a porous anodic alumina film 1 {mu}m thick with a pore diameter of 150-180 nm; the film is grown on a silicon substrate. The fabricated structures exhibit terbium photoluminescence with bands typical of trivalent terbium terms. Terbium X-ray luminescence with the most intense band at 542 nm is observed for the first time for such a structure. Morphological analysis of the structure by scanning electron microscopy shows the presence of xerogel clusters in pore channels, while the main pore volume remains unfilled and pore mouths remain open. The data obtained confirm the promising applications of fabricated structures for developing matrix converters of X-rays and other ionizing radiations into visible light. The possibilities of increasing luminescence intensity in the matrix converter are discussed.

  17. PREPARATION OF LAYERED DOUBLE HYDROXIDES

    National Research Council Canada - National Science Library

    OGAWA, MAKOTO; INOMATA, KAZUYA

    2011-01-01

    Layered double hydroxides (LDHs) are class of materials with useful properties associated with their anion exchange abilities for a wide range of applications including bio and environmental problems...

  18. Optical Properties of Lithium Terbium Fluoride and Implications for Performance in High Power Lasers (Postprint)

    Science.gov (United States)

    2016-02-01

    AFRL-RX-WP-JA-2016-0323 OPTICAL PROPERTIES OF LITHIUM TERBIUM FLUORIDE AND IMPLICATIONS FOR PERFORMANCE IN HIGH POWER LASERS... AMERICA (STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-7750 AIR...OPTICAL PROPERTIES OF LITHIUM TERBIUM FLUORIDE AND IMPLICATIONS FOR PERFORMANCE IN HIGH POWER LASERS (POSTPRINT) 5a. CONTRACT NUMBER IN-HOUSE 5b

  19. Layered double hydroxides

    DEFF Research Database (Denmark)

    López Rayo, Sandra; Imran, Ahmad; Hansen, Hans Chr. Bruun

    2017-01-01

    A novel zinc (Zn) fertilizer concept based on Zn doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthetized, their chemical composition was analyzed and their nutrient release was studied in buffered solutions with different pH values. Uptake...... the long-term Zn release capacity of LDHs complying with a release-on-demand behavior and serves as proof-of-concept that Zn-doped Mg-Fe-LDHs can be used as Zn fertilizers....

  20. Detection of biothiols in cells by a terbium chelate-Hg (II) system

    Science.gov (United States)

    Tan, Hongliang; Chen, Yang

    2012-01-01

    Great efforts have been devoted to the development of sensitive and specific analysis methods for biothiols because of their important roles in biological systems. We present a new detection system for biothiols that is based on the reversible quenching and restoration of fluorescence of terbium chelate caused by Hg2+ and thiol species. In the presence of biothiols, a restoration of fluorescence of terbium chelate after quenching by Hg2+ was observed due to the interaction of Hg2+ with thiol groups, and the restored fluorescence increased with the concentration of biothiols. This method was sensitive and selective for biothiols. The detection limit was 80 nM for glutathione, 100 nM for Hcy, and 400 nM for Cysteine, respectively. The terbium chelate-Hg (II) system was successfully applied to determine the levels of biothiols in cancer cells and urine samples. Further, it was also shown to be comparable to Ellman's assay. Compared to other fluorescence methods, the terbium chelate probe is advantageous because interference from short-lived nonspecific fluorescence can be efficiently eliminated due to the long fluorescence lifetime of terbium chelate, which allows for detection by time-resolved fluorescence. The terbium chelate probe can serve as a diagnostic tool for the detection of abnormal levels of biothiols in disease.

  1. Cryogenic temperature characteristics of Verdet constant of terbium sesquioxide ceramics

    Science.gov (United States)

    Snetkov, I. L.; Palashov, O. V.

    2016-12-01

    The dependence of the Verdet constant on temperature in the (80-300 K) range for a promising magneto-active material terbium sesquioxide Tb2O3 at the wavelengths of 405-1064 nm is considered. For each of the studied wavelengths, the Verdet constant of the material cooled down to the liquid nitrogen temperature increased by more than a factor of 3.2 as compared to the room temperature value. Similarly to the other paramagnetics, the increase follows the law ∼1/T. Approximations for the temperature dependence of the Verdet constant have been obtained and the value of 1/V·(dV/dT) has been estimated. This information is needed to determine the angle of rotation as well as the variation of the extinction ratio of a Faraday isolator with temperature and extremely important at creation a cryogenic Faraday devices.

  2. Biogenic terbium oxide nanoparticles as the vanguard against osteosarcoma

    Science.gov (United States)

    Iram, Sana; Khan, Salman; Ansary, Abu Ayoobul; Arshad, Mohd; Siddiqui, Sahabjada; Ahmad, Ejaz; Khan, Rizwan H.; Khan, Mohd Sajid

    2016-11-01

    The synthesis of inner transition metal nanoparticles via an ecofriendly route is quite difficult. This study, for the first time, reports synthesis of terbium oxide nanoparticles using fungus, Fusarium oxysporum. The biocompatible terbium oxide nanoparticles (Tb2O3 NPs) were synthesized by incubating Tb4O7 with the biomass of fungus F. oxysporum. Multiple physical characterization techniques, such as UV-visible and photoluminescence spectroscopy, TEM, SAED, and zeta-potential were used to confirm the synthesis, purity, optical and surface characteristics, crystallinity, size, shape, distribution, and stability of the nanoemulsion of Tb2O3 NPs. The Tb2O3 NPs were found to inhibit the propagation of MG-63 and Saos-2 cell-lines (IC50 value of 0.102 μg/mL) and remained non-toxic up to a concentration of 0.373 μg/mL toward primary osteoblasts. Cell viability decreased in a concentration-dependent manner upon exposure to 10 nm Tb2O3 NPs in the concentration range 0.023-0.373 μg/mL. Cell toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, and FACS analysis. Morphological examinations of cells revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The level of ROS within the cells-an indicator of oxidative stress was significantly increased. The induction of apoptosis at concentrations ≤ IC50 was corroborated by 4‧,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining (DNA damage and nuclear fragmentation). Flow-cytometric studies indicated that the response was dose dependent with a threshold effect.

  3. Layered double hydroxides

    DEFF Research Database (Denmark)

    López Rayo, Sandra; Imran, Ahmad; Hansen, Hans Chr. Bruun

    2017-01-01

    A novel zinc (Zn) fertilizer concept based on Zn doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthetized, their chemical composition was analyzed and their nutrient release was studied in buffered solutions with different pH values. Uptake...... of Zn by barley (Hordeum vulgare cv. Antonia) was evaluated in short- (8 weeks), medium- (11 weeks) and long-term (28 weeks) experiments in quartz sand and in a calcareous soil enriched with Zn-doped Mg-Fe-LDHs. The Zn release rate of the Zn-doped Mg-Fe-LDHs was described by a first-order kinetics...

  4. 21 CFR 184.1428 - Magnesium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS... a white precipitate by the addition of sodium hydroxide to a water soluble magnesium salt or by...

  5. Hydroxide catalysts for lignin depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-04-25

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  6. Hydroxide catalysts for lignin depolymerization

    Science.gov (United States)

    Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

    2017-10-17

    Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

  7. Autofluorescence-free Live-cell Imaging Using Terbium Nanoparticles.

    Science.gov (United States)

    Cardoso Dos Santos, Marcelina; Goetz, Joan; Bartenlian, Hortense; Wong, Ka-Leung; Charbonniere, Loïc Joanny; Hildebrandt, Niko

    2018-02-20

    Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and sub-cellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. Combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence, allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM. Detection of highly resolved long-lifetime (ms) PL decay curves from small (~10 µm2) areas within single cells within a few seconds emphasized the unprecedented photophysical properties of Tb-NPs for live-cell imaging that extend well beyond currently available nanometric imaging agents.

  8. Solar Thermochemical Hydrogen Production via Terbium Oxide Based Redox Reactions

    Directory of Open Access Journals (Sweden)

    Rahul Bhosale

    2016-01-01

    Full Text Available The computational thermodynamic modeling of the terbium oxide based two-step solar thermochemical water splitting (Tb-WS cycle is reported. The 1st step of the Tb-WS cycle involves thermal reduction of TbO2 into Tb and O2, whereas the 2nd step corresponds to the production of H2 through Tb oxidation by water splitting reaction. Equilibrium compositions associated with the thermal reduction and water splitting steps were determined via HSC simulations. Influence of oxygen partial pressure in the inert gas on thermal reduction of TbO2 and effect of water splitting temperature (TL on Gibbs free energy related to the H2 production step were examined in detail. The cycle (ηcycle and solar-to-fuel energy conversion (ηsolar-to-fuel efficiency of the Tb-WS cycle were determined by performing the second-law thermodynamic analysis. Results obtained indicate that ηcycle and ηsolar-to-fuel increase with the decrease in oxygen partial pressure in the inert flushing gas and thermal reduction temperature (TH. It was also realized that the recuperation of the heat released by the water splitting reactor and quench unit further enhances the solar reactor efficiency. At TH=2280 K, by applying 60% heat recuperation, maximum ηcycle of 39.0% and ηsolar-to-fuel of 47.1% for the Tb-WS cycle can be attained.

  9. Folate Receptor Targeted Alpha-Therapy Using Terbium-149

    CERN Document Server

    Müller, Cristina; Haller, Stephanie; Dorrer, Holger; Köster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Türler, Andreas; Schibli, Roger

    2014-01-01

    Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters rev...

  10. Hardness and dielectric characteristics of flux grown terbium aluminate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, K.K.; Kotru, P.N. [Jammu Univ. (India). Dept. of Physics; Tandon, R.P. [National Physical Laboratory, New Delhi (India); Wanklyn, B.M. [Clarendon Laboratory, University of Oxford, Oxford (United Kingdom)

    1999-01-29

    Results of indentation induced Vickers hardness testing and dielectric studies conducted on flux-grown terbium aluminate crystals are presented. It is shown that the Vickers hardness value (H{sub v}) is independent of indentation time, but depends on the applied load. Applying the concept of Hays and Kendall, the load independent values are estimated for (110) and (001) planes. Differential behaviour in the crack formation of two different planes (110) and (001) is observed, while (001) plane develops Palmqvist cracks in the whole load range of 10-100 g, (110) plane shows a transition from Palmqvist to median cracks at 70 g. The fracture toughness, brittleness index and yield strength are determined for both the planes. The hardness anisotropy is reported. The dielectric constant, dielectric loss and conductivity are shown to be dependent on temperature and frequency of the applied a.c. field. The dielectric constant versus temperature shows a transition peak at 230 C, which remains independent of the frequency of the applied a.c. field in the range 1 kHz-13 MHz. (orig.) 36 refs.

  11. Thermoluminescence of cerium and terbium -doped calcium pyrophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Lozano R, I. B.; Diaz G, J. A. I., E-mail: jesus.roman@nucleares.unam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

    2015-10-15

    The aim of this work is to report the thermoluminescence (Tl) response of Calcium Pyrophosphate phosphor doped with Cerium and Terbium impurities (Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+}). The phosphors were synthesized using the co-precipitation method and annealed at 900 degrees C by two hours for obtain the β phase. The intentional doping with Ce and Tb ions was 1 at.% and 0.1 at.%, whereas in the EDS results the concentration of impurities was 0.39 at.% and 0.05 at.%, respectively. The superficial morphology of phosphor is mainly composed by thin wafers of different size. All samples were exposed to gamma rays from {sup 60}Co in the Gammacell-200 irradiator. The Tl response of the phosphor was measured from Rt up to 350 degrees C and under nitrogen atmosphere in a Harshaw TLD 3500 reader. The glow curves of the Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} powders showed a broad intense Tl peak centered at 165 degrees C and a shoulder at approximate 260 degrees C was observed. A linear Tl response in the range of absorbed dose of 0.2 to 10 Gy was obtained. Tl glow curves were analyzed using the initial rise (IR)and computerized glow curve deconvolution methods to evaluate the kinetics parameters such as activation energy (E), frequency factor (s) and kinetic order (b). (Author)

  12. Solvent polarity and oxygen sensitivity, rather than viscosity, determine lifetimes of biaryl-sensitised terbium luminescence.

    Science.gov (United States)

    Walter, Edward R H; Williams, J A Gareth; Parker, David

    2017-12-14

    In a macrocyclic terbium complex incorporating a biaryl sensitiser, the observed variation of emission lifetime is shown to be determined by the solubility of oxygen in the solvent system and the relative energy of the chromophore excited state, rather than any dependence on solvent viscosity.

  13. 21 CFR 582.1428 - Magnesium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

  14. Homogeneous nucleation of magnesium hydroxide.

    Science.gov (United States)

    Klein, D H; Smith, M D; Driy, J A

    1967-08-01

    The rate of homogeneous nucleation of magnesium hydroxide has been determined as a function of solution concentration, using a quasi-homogeneous precipitation technique and electronic particle counting. The nucleation rate becomes measurable at super-saturations of about 4, and is dependent on the 33rd power of the product aMgaOH(2). The experimental results are consistent with nucleation theory. The nucleus-solution interfacial energy is calculated to be 115 erg/cm(2).

  15. Arginine-responsive terbium luminescent hybrid sensors triggered by two crown ether carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Lasheng [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Tang, Ke; Ding, Xiaoping [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhou, Zhan; Xiao, Rui [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2013-12-01

    Crown ether carboxylic acids constitute main building blocks for the synthesis of terbium containing covalent cross-linked luminescent materials. Both the complexes and the hybrid nanomaterials could exhibit remarkable green emissions in pure water. More importantly, they were found to have a profound effect on the luminescence responses to arginine compared with glutamic acid, histidine, tryptophan, threonine, tyrosine and phenylalanine in aqueous environment. The present study provided the possibility of using a host–guest mechanism as a way of signal transduction based on lanthanide supramolecular hybrid materials. - Highlights: • Crown ether carboxylic acids were found to sensitize terbium ions among a group of ethers. • The complexes and silica hybrid materials were both prepared and characterized. • They could exhibit remarkable green emissions in pure water.

  16. 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.

  17. Spectrofluorimetric Determination of Human Serum Albumin Using Terbium-Danofloxacin Probe

    OpenAIRE

    Ramezani, Amir M.; Manzoori, Jamshid L.; Amjadi, Mohammad; Jouyban, Abolghasem

    2012-01-01

    A spectrofluorimetric method is proposed for the determination of human serum albumin (HSA) and bovine serum albumin (BSA) using terbium-danofloxacin (Tb3+-Dano) as a fluorescent probe. These proteins remarkably enhance the fluorescence intensity of the Tb3+-Dano complex at 545 nm, and the enhanced fluorescence intensity of Tb3+-Dano is proportional to the concentration of proteins (HSA and BSA). Optimum conditions for the determination of HSA were investigated and found that the maximum resp...

  18. Genetically Encoded FRET-Sensor Based on Terbium Chelate and Red Fluorescent Protein for Detection of Caspase-3 Activity

    Directory of Open Access Journals (Sweden)

    Alexander S. Goryashchenko

    2015-07-01

    Full Text Available This article describes the genetically encoded caspase-3 FRET-sensor based on the terbium-binding peptide, cleavable linker with caspase-3 recognition site, and red fluorescent protein TagRFP. The engineered construction performs two induction-resonance energy transfer processes: from tryptophan of the terbium-binding peptide to Tb3+ and from sensitized Tb3+ to acceptor—the chromophore of TagRFP. Long-lived terbium-sensitized emission (microseconds, pulse excitation source, and time-resolved detection were utilized to eliminate directly excited TagRFP fluorescence and background cellular autofluorescence, which lasts a fraction of nanosecond, and thus to improve sensitivity of analyses. Furthermore the technique facilitates selective detection of fluorescence, induced by uncleaved acceptor emission. For the first time it was shown that fluorescence resonance energy transfer between sensitized terbium and TagRFP in the engineered construction can be studied via detection of microsecond TagRFP fluorescence intensities. The lifetime and distance distribution between donor and acceptor were calculated using molecular dynamics simulation. Using this data, quantum yield of terbium ions with binding peptide was estimated.

  19. Green light emission in aluminum oxide powders doped with different terbium concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Mariscal B, L; Falcony, C. [IPN, Centro de Investigacion y de Estudios Avanzados, 07360 Ciudad de Mexico (Mexico); Carmona T, S.; Murrieta, H.; Sanchez A, M. A. [UNAM, Instituto de Fisica, 04510 Ciudad de Mexico (Mexico); Vazquez A, R. [IPN, Escuela Superior de Computo, 07738 Ciudad de Mexico (Mexico); Garcia R, C. M., E-mail: mariscal2005@gmail.com [UNAM, Facultad de Ciencias, 04510 Ciudad de Mexico (Mexico)

    2016-11-01

    Different emission intensities presented in aluminum oxide phosphors corresponding to different concentrations of doping performed with terbium are analyzed. The phosphors were synthesized by the evaporation technique and were characterized by photo and cathodoluminescence, X-ray diffraction and EDS techniques for different incorporation percentages of terbium as dopant; they show characteristic transitions in 494, 543, 587 and 622 nm, corresponding to {sup 5}D{sub 4} → {sup 7}F{sub 6}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, {sup 5}D{sub 4} → {sup 7}F{sub 4} and {sup 5}D{sub 4} → {sup 7}F{sub 3}, respectively when they are excited with λ{sub exc} = 380 nm wavelength at room temperature. The results of X-ray diffraction show the presence of α-Al{sub 2}O{sub 3} phases with peaks located at 2θ = 25.78, 35.34, 37.96, 43.56, 45.8, 52.74, 57.7, 61.5, 66.74, 68.44, 77.12 and 80.94, and the δ-Al{sub 2}O-3 phase 2θ = 32.82, 45.8, 61.36 and 66.74. These compounds were heat treated for two hours at 1100 degrees Celsius. EDS analyzes indicate that these compounds have close to 60% oxygen around of 40% aluminum in the presence of terbium as dopant which indicates a stoichiometry close to the expected one for alumina. (Author)

  20. Graphene quantum dots-terbium ions as novel sensitive and selective time-resolved luminescent probes.

    Science.gov (United States)

    Llorent-Martínez, Eulogio J; Durán, Gema M; Ríos, Ángel; Ruiz-Medina, Antonio

    2018-01-01

    We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes. Ascorbic acid was selected as a target analyte to demonstrate the suitability of the proposed method. The selectivity of the TSL method was highly improved for most of the interferences tested. Under the optimum conditions [Tb(III) concentration 5 × 10-4 mol L-1, GQD concentration 4 mg L-1], a minimum 100% increase in selectivity was observed for several vitamins and common cations that may be present in the samples to be analyzed. In addition, the analytical signal showed a 30% enhancement with the use of GQDs compared with the use of merely Tb(III) ions, with a detection limit of 0.12 μg mL-1. The repeatability and intermediate precision were lower than 3% and 5%, respectively. From the results obtained, the implementation of GQDs in TSL can lead to the development of novel time-resolved luminescent probes with high analytical potential. Graphical abstract Quenching of Tb(III)-graphene quantum dot (GQD) luminescence by ascorbic acid (AA). TBL terbium-sensitized luminescence.

  1. Fluorescence study of some terbium-oligopeptide complexes in methanolic solution.

    Science.gov (United States)

    Rabouan, S; Delage, J; Durand, W; Prognon, P; Barthes, D

    2000-04-03

    This study concerned the use of lanthanide chelates to detect glycyl-leucyl-phenylalanine (GLF) and its homologues. Spectroscopic analysis of peptides without or with terbium complexation revealed the formation of (LF)(3)(Tb)(2), (GF)(3)(Tb)(2), (GLF)(3)(Tb)(2) and (FL)(4)Tb, (FG)(4)Tb complexes with high stability constants in methanolic solutions (pK(d)>13). Lanthanide chelate emission displayed a large Stokes shift (>270 nm), which allowed Tb chelates of GLF and its derivatives to be used for detection purposes. However, this preliminary study indicated some important limitations associated with lanthanide chelation, such as high methanolic content.

  2. Electromagnetic properties of terbium gallium garnet at millikelvin temperatures and low photon energy

    Science.gov (United States)

    Kostylev, Nikita; Goryachev, Maxim; Bushev, Pavel; Tobar, Michael E.

    2017-07-01

    Electromagnetic properties of single crystal terbium gallium garnet are characterised from room down to millikelvin temperatures using the whispering gallery mode method. Microwave spectroscopy is performed at low powers equivalent to a few photons in energy and conducted as functions of the magnetic field and temperature. A phase transition is detected close to the temperature of 3.5 K. This is observed for multiple whispering gallery modes causing an abrupt negative frequency shift and a change in transmission due to extra losses in the new phase caused by a change in complex magnetic susceptibility.

  3. Nuclear excitation functions from 40 to 200 MeV proton irradiation of terbium

    Energy Technology Data Exchange (ETDEWEB)

    Engle, Jonathan W., E-mail: jwengle@lanl.gov; Mashnik, Stepan G.; Parker, Lauren A.; Jackman, Kevin R.; Bitteker, Leo J.; Ullmann, John L.; Gulley, Mark S.; Pillai, Chandra; John, Kevin D.; Birnbaum, Eva R.; Nortier, Francois M.

    2016-01-01

    Nuclear formation cross sections are reported for 26 radionuclides, measured with 40–200 MeV proton irradiations of terbium foils. These data provide the basis for the production of medically relevant radionuclides (e.g., {sup 152}Tb, {sup 155}Tb, {sup 155}Eu, and {sup 156}Eu) and {sup 153}Gd, a potential source used in ongoing efforts to characterize stellar nucleosynthesis routes. Computational predictions from the ALICE2011, CEM03.03, Bertini, and INCL + ABLA codes are compared with newly measured data to contribute to the ongoing process of code development, and yields are calculated for selected radionuclides using measured data.

  4. Aluminum hydroxide nanoparticles show a stronger vaccine adjuvant activity than traditional aluminum hydroxide microparticles

    OpenAIRE

    Li, Xinran; Aldayel, Abdulaziz M.; Cui, Zhengrong

    2013-01-01

    Aluminum hydroxide is used as a vaccine adjuvant in various human vaccines. Unfortunately, despite its favorable safety profile, aluminum hydroxide can only weakly or moderately potentiate antigen-specific antibody responses. When dispersed in an aqueous solution, aluminum hydroxide forms particulates of 1–20 µm. There is increasing evidence that nanoparticles around or less than 200 nm as vaccine or antigen carriers have a more potent adjuvant activity than large microparticles. In the prese...

  5. Aluminum hydroxide nanoparticles show a stronger vaccine adjuvant activity than traditional aluminum hydroxide microparticles.

    Science.gov (United States)

    Li, Xinran; Aldayel, Abdulaziz M; Cui, Zhengrong

    2014-01-10

    Aluminum hydroxide is used as a vaccine adjuvant in various human vaccines. Unfortunately, despite its favorable safety profile, aluminum hydroxide can only weakly or moderately potentiate antigen-specific antibody responses. When dispersed in an aqueous solution, aluminum hydroxide forms particulates of 1-20μm. There is increasing evidence that nanoparticles around or less than 200nm as vaccine or antigen carriers have a more potent adjuvant activity than large microparticles. In the present study, we synthesized aluminum hydroxide nanoparticles of 112nm. Using ovalbumin and Bacillus anthracis protective antigen protein as model antigens, we showed that protein antigens adsorbed on the aluminum hydroxide nanoparticles induced a stronger antigen-specific antibody response than the same protein antigens adsorbed on the traditional aluminum hydroxide microparticles of around 9.3μm. The potent adjuvant activity of the aluminum hydroxide nanoparticles was likely related to their ability to more effectively facilitate the uptake of the antigens adsorbed on them by antigen-presenting cells. Finally, the local inflammation induced by aluminum hydroxide nanoparticles in the injection sites was milder than that induced by microparticles. Simply reducing the particle size of the traditional aluminum hydroxide adjuvant into nanometers represents a novel and effective approach to improve its adjuvanticity. © 2013.

  6. Single sheet metal oxides and hydroxides

    DEFF Research Database (Denmark)

    Huang, Lizhi

    The synthesis of layered double hydroxides (LDHs) provides a relatively easy and traditional way to build versatile chemical compounds with a rough control of the bulk structure. The delamination of LDHs to form their single host layers (2D nanosheets) and the capability to reassemble them offer ......) Delamination of the LDHs structure (oxGRC12) with the formation of single sheet iron (hydr)oxide (SSI). (3) Assembly of the new 2D nanosheets layer by layer to achieve desired functionalities....

  7. Micelle-enhanced and terbium-sensitized spectrofluorimetric determination of gatifloxacin and its interaction mechanism

    Science.gov (United States)

    Guo, Changchuan; Wang, Lei; Hou, Zhun; Jiang, Wei; Sang, Lihong

    2009-05-01

    A terbium-sensitized spectrofluorimetric method using an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS), was developed for the determination of gatifloxacin (GFLX). A coordination complex system of GFLX-Tb 3+-SDBS was studied. It was found that SDBS significantly enhanced the fluorescence intensity of the complex (about 11-fold). Optimal experimental conditions were determined as follows: excitation and emission wavelengths of 331 and 547 nm, pH 7.0, 2.0 × 10 -4 mol l -1 terbium (III), and 2.0 × 10 -4 mol l -1 SDBS. The enhanced fluorescence intensity of the system (Δ If) showed a good linear relationship with the concentration of GFLX over the range of 5.0 × 10 -10 to 5.0 × 10 -8 mol l -1 with a correlation coefficient of 0.9996. The detection limit (3 σ) was determined as 6.0 × 10 -11 mol l -1. This method has been successfully applied to the determination of GFLX in pharmaceuticals and human urine/serum samples. Compared with most of other methods reported, the rapid and simple procedure proposed in the text offers higher sensitivity, wider linear range, and better stability. The interaction mechanism of the system is also studied by the research of ultraviolet absorption spectra, surface tension, solution polarity and fluorescence polarization.

  8. 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

  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. Synthesis of layered double hydroxides from eggshells

    Energy Technology Data Exchange (ETDEWEB)

    Li Songnan [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Wang Fangyong [College of Engineering and Technology, Northeast Forestry University, 150001 (China); Jing Xiaoyan [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Wang Jun, E-mail: zhqw1888@sohu.com [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China); Saba, Jamil; Liu Qi; Ge Lan; Song Dalei; Zhang Milin [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, 150001 (China)

    2012-01-16

    Graphical abstract: This is the XRD pattern and TEM image of 4Ca-Al layered double hydroxide, which is obtained from eggshells. It can be seen that the sample is of layered double hydroxide and shows the plate-like agglomerations with an average size of 20-100 nm. Highlights: Black-Right-Pointing-Pointer We synthesize layered double hydroxides from eggshells. Black-Right-Pointing-Pointer Eggshells are the mainly material in this method. Black-Right-Pointing-Pointer The additional alkaline solution is not required. - Abstract: Ca-Al and Ca-Fe layered double hydroxides (LDHs) were successfully synthesized from chicken eggshells by an ultrasonic wave assistant method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. XRD and TEM analyses showed that the 4Ca-Al LDHs were of high purity but other samples were not. The present study provides a simple, efficient and environmental friendly method to obtain LDHs from biowaste eggshells, in which additional alkaline solution is not required for synthesis. Moreover, eggshells provide all the requisite bivalent metal ions, which are needed to form layered double hydroxides.

  11. Iodine Sequestration Using Delafossites and Layered Hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    J.D. Pless; J.B. Chwirka; J.L. Krumhansl

    2006-03-28

    The objective of this document is to report on early success for sequestering {sup 129}I. Sorption coefficients (K{sub d}) for I{sup -} and IO{sub 3}{sup -} onto delafossites, spinels and layered metal hydroxides were measured in order to compare their applicability for sequestering {sup 129}I. The studies were performed using a dilute fluid composition representative of groundwater indigenous to the Yucca mountain area. Delafossites generally exhibited relatively poor sorption coefficients (< 10{sup 1.7} mL/g). In contrast, the composition of the layered hydroxides significantly affects their ability to sorb I. Cu/Al and Cu/Cr layered hydroxide samples exhibit K{sub d}'s greater than 10{sup 3} mL/g for both I{sup -} and IO{sub 3}{sup -}.

  12. Thermo-transferred thermoluminescence (TTTl) in potassium-yttrium double fluoride doped with terbium

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, A.; Rivera, T.; Diaz G, J. A. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico); Azorin, J. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Azorin, J. C. [Universidad de Guanajuato, Division de Ciencias e Ingenierias-Campus Leon, Lomas del Bosque No. 103, Col. Lomas del Campestre, 37000 Leon, Guanajuato (Mexico); Licona, R.; Rivas, F.; Hernandez C, G. [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Quimicas, 14 Sur y San Claudio, Ciudad Universitaria, Puebla de Zaragoza, Puebla (Mexico); Khaidukov, N. [Institute of General and Inorganic Chemistry, Lenin SK 11 Prospect 31, Moscow 117907 (Russian Federation)

    2011-02-15

    This paper presents results of studying the thermo-transferred thermoluminescence (TTTl) phenomenon in potassium-yttrium double fluoride doped with terbium (K{sub 2}YF{sub 5:}Tb) at different impurity concentrations (0.8%, 0.95% and 0.99%). Previously to study the TTTl phenomenon, structural characterization and chemical composition of the materials were determined. The structural studies were conducted using a scanning electron microscope; meanwhile, chemical composition was analyzed using energy dispersive X-ray spectroscopy. Thermoluminescence kinetics was studied irradiating the samples with {sup 137}Cs gamma rays as well as with {sup 90}Sr/{sup 90}Y beta rays, analyzing the glow curves by the deconvolution method for obtaining the kinetic parameters. (Author)

  13. The influence of pressure on the photoluminescence properties of a terbium-adipate framework

    Science.gov (United States)

    Spencer, Elinor C.; Zhao, Jing; Ross, Nancy L.; Andrews, Michael B.; Surbella, Robert G.; Cahill, Christopher L.

    2013-06-01

    The influence of pressure (over the 0-4.7 GPa range) on the photoluminescence emissions and crystal structure of the known 3D terbium-adipate metal-organic framework material Tb-GWMOF6 has been evaluated by high-pressure single-crystal X-ray diffraction and spectroscopic techniques. The results from this study show that this complex lanthanide framework structure undergoes three phase transitions within the 0-4 GPa pressure range that involve alterations in the number of symmetry independent Tb3+ ion sites within the crystal lattice. These pressure induced modifications to the structure of Tb-GWMOF6 lead to pronounced changes in the profiles of the 5D4→7F5 emission spectra of this complex.

  14. Terbium Radionuclides for Theranostics Applications: A Focus On MEDICIS-PROMED

    Science.gov (United States)

    Cavaier, R. Formento; Haddad, F.; Sounalet, T.; Stora, T.; Zahi, I.

    A new facility, named CERN-MEDICIS, is under construction at CERN to produce radionuclides for medical applications. In parallel, the MEDICIS-PROMED, a Marie Sklodowska-Curie innovative training network of the Horizon 2020 European Commission's program, is being coordinated by CERN to train young scientists on the production and use of innovative radionuclides and develop a network of experts within Europe. One program within MEDICIS-PROMED is to determine the feasibility of producing innovative radioisotopes for theranostics using a commercial middle-sized high-current cyclotron and the mass separation technology developed at CERN-MEDICIS. This will allow the production of high specific activity radioisotopes not achievable with the common post-processing by chemical separation. Radioisotopes of scandium, copper, arsenic and terbium have been identified. Preliminary studies of activation yield and irradiation parameters optimization for the production of Tb-149 will be described.

  15. Dielectric and conducting behavior of gadolinium-terbium fumarate heptahydrate crystals

    Science.gov (United States)

    Shah, M. D.; Want, B.

    2015-07-01

    Gadolinium-terbium fumarate heptahydrate crystals were grown in silica gel by using single gel diffusion technique. The crystals were characterized by different physico-chemical techniques of characterization. Powder X-ray diffraction results showed that the grown material is purely crystalline in nature. Elemental analyses suggested the chemical formula of the compound to be Gd Tb (C4H2O4)3ṡ7H2O. Energy dispersive X-ray analysis confirmed the presence of Gd and Tb in the title compound. The dielectric and conductivity studies of the grown compound were carried as function of frequency of applied field and the temperature. The grown material showed a dielectric anomaly which was correlated with its thermal behavior. The ac conductivity of the material showed Jonscher's power law behavior: σ(ω)=σo+Aωs, with a temperature-dependent power exponent s(<1). The conductivity was found to be a function of temperature and frequency.

  16. Highly sensitive detection of dipicolinic acid with a water-dispersible terbium-metal organic framework.

    Science.gov (United States)

    Bhardwaj, Neha; Bhardwaj, Sanjeev; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

    2016-12-15

    The sensitive detection of dipicolinic acid (DPA) is strongly associated with the sensing of bacterial organisms in food and many types of environmental samples. To date, the demand for a sensitive detection method for bacterial toxicity has increased remarkably. Herein, we investigated the DPA detection potential of a water-dispersible terbium-metal organic framework (Tb-MOF) based on the fluorescence quenching mechanism. The Tb-MOF showed a highly sensitive ability to detect DPA at a limit of detection of 0.04nM (linear range of detection: 1nM to 5µM) and also offered enhanced selectivity from other commonly associated organic molecules. The present study provides a basis for the application of Tb-MOF for direct, convenient, highly sensitive, and specific detection of DPA in the actual samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. A New Bis(phthalocyaninato) Terbium Single-Ion Magnet with an Overall Excellent Magnetic Performance.

    Science.gov (United States)

    Chen, Yuxiang; Ma, Fang; Chen, Xiaoxiang; Dong, Bowei; Wang, Kang; Jiang, Shangda; Wang, Chiming; Chen, Xin; Qi, Dongdong; Sun, Haoling; Wang, Bingwu; Gao, Song; Jiang, Jianzhuang

    2017-11-20

    Bulky and strong electron-donating dibutylamino groups were incorporated onto the peripheral positions of one of the two phthalocyanine ligands in the bis(phthalocyaninato) terbium complex, resulting in the isolation of heteroleptic double-decker (Pc)Tb{Pc[N(C4H9)2]8} {Pc = phthalocyaninate; Pc[N(C4H9)2]8 = 2,3,9,10,16,17,23,24-octakis(dibutylamino)phthalocyaninate} with the nature of an unsymmetrical molecular structure, a square-antiprismatic coordination geometry, an intensified coordination field strength, and the presence of organic radical-f interaction. As a total result of all these factors, this sandwich-type tetrapyrrole lanthanide single-ion magnet (SIM) exhibits an overall enhanced magnetic performance including a high blocking temperature (TB) of 30 K and large effective spin-reversal energy barrier of Ueff = 939 K, rendering it the best sandwich-type tetrapyrrole lanthanide SIM reported thus far.

  18. Ultralarge magneto-optic rotations and rotary dispersion in terbium gallium garnet single crystal.

    Science.gov (United States)

    Shaheen, Amrozia; Majeed, Hassaan; Anwar, Muhammad Sabieh

    2015-06-10

    We report systematically acquired data on the Verdet constant of terbium gallium garnet for wavelengths ranging from visible to near-infrared (405-830 nm) regime. Our experimental method of Stokes polarimetry is based on the Fourier decomposition of the received light intensity and allows unambiguous determination of both the Faraday rotation and the ellipticity of the emergent light. Temperature-dependent investigations in the range of 8-300 K extend earlier reports and verify the Verdet's constant direct dependence on the magnetization, whose first-order approximation is simply a manifestation of the Curie's law. Further, a least-squares fitting of the experimental data correlates well with theoretical predictions. At a wavelength of 405 nm and temperature of 8 K, the rotation is approximately 500°.

  19. Terbium fluorescence as a sensitive, inexpensive probe for UV-induced damage in nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    El-Yazbi, Amira F.; Loppnow, Glen R., E-mail: glen.loppnow@ualberta.ca

    2013-07-05

    Graphical abstract: -- Highlights: •Simple, inexpensive, mix-and-read assay for positive detection of DNA damage. •Recognition of undamaged DNA via hybridization to a hairpin probe. •Terbium(III) fluorescence reports the amount of damage by binding to ssDNA. •Tb/hairpin is a highly selective and sensitive fluorescent probe for DNA damage. -- Abstract: Much effort has been focused on developing methods for detecting damaged nucleic acids. However, almost all of the proposed methods consist of multi-step procedures, are limited, require expensive instruments, or suffer from a high level of interferences. In this paper, we present a novel simple, inexpensive, mix-and-read assay that is generally applicable to nucleic acid damage and uses the enhanced luminescence due to energy transfer from nucleic acids to terbium(III) (Tb{sup 3+}). Single-stranded oligonucleotides greatly enhance the Tb{sup 3+} emission, but duplex DNA does not. With the use of a DNA hairpin probe complementary to the oligonucleotide of interest, the Tb{sup 3+}/hairpin probe is applied to detect ultraviolet (UV)-induced DNA damage. The hairpin probe hybridizes only with the undamaged DNA. However, the damaged DNA remains single-stranded and enhances the intrinsic fluorescence of Tb{sup 3+}, producing a detectable signal directly proportional to the amount of DNA damage. This allows the Tb{sup 3+}/hairpin probe to be used for sensitive quantification of UV-induced DNA damage. The Tb{sup 3+}/hairpin probe showed superior selectivity to DNA damage compared to conventional molecular beacons probes (MBs) and its sensitivity is more than 2.5 times higher than MBs with a limit of detection of 4.36 ± 1.2 nM. In addition, this probe is easier to synthesize and more than eight times cheaper than MBs, which makes its use recommended for high-throughput, quantitative analysis of DNA damage.

  20. Fine- and hyperfine structure investigations of even configuration system of atomic terbium

    Science.gov (United States)

    Stefanska, D.; Elantkowska, M.; Ruczkowski, J.; Furmann, B.

    2017-03-01

    In this work a parametric study of the fine structure (fs) and the hyperfine structure (hfs) for the even-parity configurations of atomic terbium (Tb I) is presented, based in considerable part on the new experimental results. Measurements on 134 spectral lines were performed by laser induced fluorescence (LIF) in a hollow cathode discharge lamp; on this basis, the hyperfine structure constants A and B were determined for 52 even-parity levels belonging to the configurations 4f85d6s2, 4f85d26s or 4f96s6p; in all the cases those levels were involved in the transitions investigated as the lower levels. For 40 levels the hfs was examined for the first time, and for the remaining 12 levels the new measurements supplement our earlier results. As a by-product, also preliminary values of the hfs constants for 84 odd-parity levels were determined (the investigations of the odd-parity levels system in the terbium atom are still in progress). This huge amount of new experimental data, supplemented by our earlier published results, were considered for the fine and hyperfine structure analysis. A multi-configuration fit of 7 configurations was performed, taking into account second-order of perturbation theory, including the effects of closed shell-open shell excitations. Predicted values of the level energies, as well as of magnetic dipole and electric quadrupole hyperfine structure constants A and B, are quoted in cases when no experimental values are available. By combining our experimental data with our own semi-empirical procedure it was possible to identify correctly the lower and upper level of the line 544.1440 nm measured by Childs with the use of the atomic-beam laser-rf double-resonance technique (Childs, J Opt Soc Am B 9;1992:191-6).

  1. Structural and optical characterization of terbium doped ZnGa2O4 thin films deposited by RF magnetron sputtering

    Science.gov (United States)

    Somasundaram, K.; Girija, K. G.; Sudarsan, V.; Selvin, P. Christopher; Vatsa, R. K.

    2016-05-01

    Tb3+ doped ZnGa2O4 nanophosphor (21 nm) has been synthesized via low temperature polyol route and subsequently thin films of the same were deposited on glass and ITO substrates by RF magnetron sputtering. The films were characterized by X-ray Diffraction and luminescence measurements. The XRD pattern showed that Tb3+ doped ZnGa2O4 nanophosphor has a cubic spinel phase. Luminescence behavior of the nanophosphor and as deposited sputtered film was investigated. The PL emission spectra of nanophosphor gave a broad ZnGa2O4 host emission band along with a strong terbium emission and the thin films showed only broad host emission band and there was no terbium ion emission.

  2. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, Robert W. [Univ. of California, Berkeley, CA (United States); Muller, Rolf H. [Univ. of California, Berkeley, CA (United States)

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 - 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  3. Structural transformation of nickel hydroxide films during anodic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, R.W.; Muller, R.H.

    1992-05-01

    The transformation of anodically formed nickel hydroxide/oxy-hydroxide electrodes has been investigated. A mechanism is proposed for the anodic oxidation reaction, in which the reaction interface between the reduced and oxidized phases of the electrode evolves in a nodular topography that leads to inefficient utilization of the active electrode material. In the proposed nodular transformation model for the anodic oxidation reaction, nickel hydroxide is oxidized to nickel oxy-hydroxide in the region near the metal substrate. Since the nickel oxy-hydroxide is considerably more conductive than the surrounding nickel hydroxide, as further oxidation occurs, nodular features grow rapidly to the film/electrolyte interface. Upon emerging at the electrolyte interface, the reaction boundary between the nickel hydroxide and oxy-hydroxide phases spreads laterally across the film/electrolyte interface, creating an overlayer of nickel oxy-hydroxide and trapping uncharged regions of nickel hydroxide within the film. The nickel oxy-hydroxide overlayer surface facilitates the oxygen evolution side reaction. Scanning tunneling microscopy of the electrode in its charged state revealed evidence of 80 {endash} 100 Angstrom nickel oxy-hydroxide nodules in the nickel hydroxide film. In situ spectroscopic ellipsometer measurements of films held at various constant potentials agree quantitatively with optical models appropriate to the nodular growth and subsequent overgrowth of the nickel oxy-hydroxide phase. A two-dimensional, numerical finite difference model was developed to simulate the current distribution along the phase boundary between the charged and uncharged material. The model was used to explore the effects of the physical parameters that govern the electrode behavior. The ratio of the conductivities of the nickel hydroxide and oxy-hydroxide phases was found to be the dominant parameter in the system.

  4. Polysulfide intercalated layered double hydroxides for metal capture applications

    Energy Technology Data Exchange (ETDEWEB)

    Kanatzidis, Mercouri G.; Ma, Shulan

    2017-04-04

    Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

  5. 21 CFR 73.2326 - Chromium hydroxide green.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.2326 Section 73.2326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and specifications.The color additive chromium hydroxide green shall conform in identity and specifications to the...

  6. 21 CFR 73.1326 - Chromium hydroxide green.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O...

  7. 40 CFR 721.4600 - Recovered metal hydroxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN P-91-809...

  8. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Alumina (dried aluminum hydroxide). 73.1010... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white, odorless...

  9. KINETICS OF HYDROXIDE PHOMOTED DECOMPOSITION 0F ...

    African Journals Online (AJOL)

    1991-04-26

    (Received July 2?. 1990; revised April 26, 1991). ABSTRACT. The effects of varying concentrations of dimethyl sulphoxide in mixture with water on rates and activation parameters for the hydroxide promoted decomposition of tetraphenylphosphonium chloride have been studied. Increasing the DMSO content of the reaction ...

  10. COMBINED ALUMINIUM SULFATE/HYDROXIDE PROCESS FOR ...

    African Journals Online (AJOL)

    community level. KEY WORDS: Nalgonda Technique, Aluminium sulfate, Aluminium hydroxide, Fluoride, Drinking water. INTRODUCTION. Fluoride is a common constituent in natural waters or wastewaters. It may originate from either natural geological sources or industries that use fluoride-containing compounds as raw.

  11. 21 CFR 184.1763 - Sodium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... solution and also by reacting calcium hydroxide with sodium carbonate. (b) The ingredient meets the... following current good manufacturing practice conditions of use: (1) The ingredient is used as a pH control... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

  12. Thermal formation of corundum from aluminium hydroxides ...

    Indian Academy of Sciences (India)

    Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form -Al2O3 at ∼ 400°C but the formation of -Al2O3 at 1200°C occurs more readily in the material derived ...

  13. Hydroxide catalysis bonding of silicon carbide

    NARCIS (Netherlands)

    Veggel, A.A. van; Ende, D.A. van den; Bogenstahl, J.; Rowan, S.; Cunningham, W.; Gubbels, G.H.M.; Nijmeijer, H.

    2008-01-01

    For bonding silicon carbide optics, which require extreme stability, hydroxide catalysis bonding is considered [Rowan, S., Hough, J. and Elliffe, E., Silicon carbide bonding. UK Patent 040 7953.9, 2004. Please contact Mr. D. Whiteford for further information: D.Whiteford@admin.gla.ac.uk]. This

  14. Determination of fluoxetine in pharmaceutical and biological samples based on the silver nanoparticle enhanced fluorescence of fluoxetine-terbium complex.

    Science.gov (United States)

    Lotfi, Ali; Manzoori, Jamshid L

    2016-11-01

    In this study, a simple and sensitive spectrofluorimetric method is presented for the determination of fluoxetine based on the enhancing effect of silver nanoparticles (AgNPs) on the terbium-fluoxetine fluorescence emission. The AgNPs were prepared by a simple reduction method and characterized by UV-Vis spectroscopy and transmission electron microscopy. It was indicated that these AgNPs have a remarkable amplifying effect on the terbium-sensitized fluorescence of fluoxetine. The effects of various parameters such as AgNP and Tb(3+) concentration and the pH of the media were investigated. Under obtained optimal conditions, the fluorescence intensity of the terbium-fluoxetine-AgNP system was enhanced linearly by increasing the concentration of fluoxetine in the range of 0.008 to 19 mg/L. The limit of detection (b + 3s) was 8.3 × 10(-4) mg/L. The interference effects of common species found in real samples were also studied. The method had good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of fluoxetine in tablet formulations, human urine and plasma samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Neutron Diffraction and Electrical Transport Studies on Magnetic Transition in Terbium at High Pressures and Low Temperatures

    Science.gov (United States)

    Thomas, Sarah; Montgomery, Jeffrey; Tsoi, Georgiy; Vohra, Yogesh; Weir, Samuel; Tulk, Christopher; Moreira Dos Santos, Antonio

    2013-06-01

    Neutron diffraction and electrical transport measurements have been carried out on the heavy rare earth metal terbium at high pressures and low temperatures in order to elucidate its transition from a helical antiferromagnetic to a ferromagnetic ordered phase as a function of pressure. The electrical resistance measurements using designer diamonds show a change in slope as the temperature is lowered through the ferromagnetic Curie temperature. The temperature of the ferromagnetic transition decreases at a rate of -16.7 K/GPa till 3.6 GPa, where terbium undergoes a structural transition from hexagonal close packed (hcp) to an α-Sm phase. Above this pressure, the electrical resistance measurements no longer exhibit a change in slope. In order to confirm the change in magnetic phase suggested by the electrical resistance measurements, neutron diffraction measurements were conducted at the SNAP beamline at the Oak Ridge National Laboratory. Measurements were made at pressures to 5.3 GPa and temperatures as low as 90 K. An abrupt increase in peak intensity in the neutron diffraction spectra signaled the onset of magnetic order below the Curie temperature. A magnetic phase diagram of rare earth metal terbium will be presented to 5.3 GPa and 90 K based on these studies.

  16. Study of Silver Nanoparticles Sensitized Fluorescence and Second-Order Scattering of Terbium(III-Pefloxacin Mesylate Complex and Determination of Pefloxacin Mesylate

    Directory of Open Access Journals (Sweden)

    Aiyun Li

    2014-01-01

    Full Text Available α-Keto acid of pefloxacin mesylate (PFLX can form the complex with Terbium(III. The intramolecular energy from PFLX to Terbium(III ion takes place when excited, and thus Terbium(III excited state is formed and then emits the characteristic fluorescence of Terbium(III, locating at 490, 545, 580, and 620 nm. The second-order scattering (SOS peak at 545 nm also appears for the complex with the exciting wavelength of 273 nm. When the silver nanoparticles are added to the system, the luminescence intensity at 545 nm greatly increased. So, with the adding of nanoparticles to the Terbium(III-PFLX complex, not only is the intramolecular energy promoted but also the SOS intensity is enhanced. The experimental results show that it is the silver nanoparticles with certain size and certain concentration which can greatly enhance the fluorescence-SOS intensity, and the relative intensity at 545 nm is proportional to the amount of PFLX. Based on this phenomenon, a novel method for the determination of PFLX has been developed and applied to the determination of PFLX in capsule and serum samples.

  17. Influence of crystalline structure on the luminescence properties of terbium orthotantalates

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, Kisla P.F. [Departamento de Química, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, ICEB II, Ouro Preto 35400-000, Minas Gerais (Brazil); Carmo, Alexandre P. [Instituto Federal Fluminense, Campus Cabo Frio, RJ 28909-971 (Brazil); Bell, Maria J.V. [Departamento de Física, Universidade Federal de Juiz de Fora, Juiz de Fora 36036-330, MG (Brazil); Dias, Anderson, E-mail: anderson_dias@iceb.ufop.br [Departamento de Química, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, ICEB II, Ouro Preto 35400-000, Minas Gerais (Brazil)

    2013-06-15

    Terbium orthotantalate powders were produced with M-fergusonite type (I2/a) and M′-fergusonite type (P2/a) structures. The samples were studied by X-ray diffraction, Raman scattering, and photoluminescence measurements (emission and decay curves). The results showed that crystalline materials were obtained with all the 18 Raman-active modes predicted by group theory calculations. Also, it was observed through photoluminescence decay curves that the Tb{sup 3+} ions occupies only one-symmetry site in both crystallographic arrangements. Photoluminescence emission curves exhibited some variation in spectral shape, peak position, and relative intensity as a consequence of their different crystalline arrangements. The dominated emission of Tb{sup 3+} ({sup 5}D{sub 4}→{sup 7}F{sub 5}) is centered with a maximum intensity at 549.2 nm (M-type) and 543.0 nm (M′-type). Fluorescence lifetimes for M-TbTaO{sub 4} and M′-TbTaO{sub 4} were determined as 33.4 μs and 1.25 ms, respectively. M′-type materials seems to be the most suitable for luminescent devices and could be a potential green luminescent material due to the strongest emission if compared with the M-fergusonite type. -- Highlights: ► Terbium orthotantalates were prepared in two different crystalline structures: I2/a and P2/a. ► XRD and Raman scattering showed that the different space groups obtained were exhibited all the 18 Raman-active modes. ► PL decay curves that the Tb{sup 3+} ions occupies only one-symmetry site in both crystallographic arrangements. ► Dominated emission of Tb{sup 3+} ({sup 5}D{sub 4}→{sup 7}F{sub 5}) is centered with a maximum intensity at 549 nm (M-type) and 543 nm (M′-type). ► Fluorescence lifetimes for M-TbTaO{sub 4} and M′-TbTaO{sub 4} were determined as 33.4 μs and 1.25 ms, respectively.

  18. In situ preparation of Calcium hydroxide films

    Energy Technology Data Exchange (ETDEWEB)

    Dahle, S.; Voigts, F. [Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Maus-Friedrichs, W., E-mail: w.maus-friedrichs@pe.tu-clausthal.de [Institut fuer Physik und Physikalische Technologien, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany); Clausthaler Zentrum fuer Materialtechnik, Technische Universitaet Clausthal, Leibnizstrasse 4, 38678 Clausthal-Zellerfeld (Germany)

    2011-10-31

    The in situ preparation of Calcium hydroxide films in an ultra high vacuum (UHV) is constrained by the decomposition of species at the surface and the absence of OH bulk diffusion. Therefore, it is not possible to prepare such films simply by water exposure to a Calcium layer. We present four different approaches for the preparation of Ca(OH){sub 2} films in an UHV. Two of these methods are found to be ineffective for the preparation, the other two are shown to produce Calcium hydroxide films. Both of the two effective procedures make use of H{sub 2} gas exposure. Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy, and X-ray Photoelectron Spectroscopy are employed to verify quality and purity of the films.

  19. Reversible flocculation of microalgae using magnesium hydroxide

    OpenAIRE

    Vandamme, Dries; Beuckels, Annelies; Markou, Giorgos; Foubert, Imogen; Muylaert, Koenraad

    2015-01-01

    Flocculation of microalgae is a promising low-cost strategy to harvest microalgae for bulk biomass production. However, residual flocculants can interfere in further downstream processes or influence biomass quality. In this study, a new concept is demonstrated based on reversible magnesium hydroxide flocculation, using Chlorella vulgaris and Phaeodactylum tricornutum as, respectively, a freshwater and a marine model species. We show that flocculation was induced by precipitation of magnesium...

  20. Pressure-induced decomposition of indium hydroxide.

    Science.gov (United States)

    Gurlo, Aleksander; Dzivenko, Dmytro; Andrade, Miria; Riedel, Ralf; Lauterbach, Stefan; Kleebe, Hans-Joachim

    2010-09-15

    A static pressure-induced decomposition of indium hydroxide into metallic indium that takes place at ambient temperature is reported. The lattice parameter of c-In(OH)(3) decreased upon compression from 7.977(2) to approximately 7.45 A at 34 GPa, corresponding to a decrease in specific volume of approximately 18%. Fitting the second-order Birch-Murnaghan equation of state to the obtained compression data gave a bulk modulus of 99 +/- 3 GPa for c-In(OH)(3). The c-In(OH)(3) crystals with a size of approximately 100 nm are comminuted upon compression, as indicated by the grain-size reduction reflected in broadening of the diffraction reflections and the appearance of smaller (approximately 5 nm) incoherently oriented domains in TEM. The rapid decompression of compressed c-In(OH)(3) leads to partial decomposition of indium hydroxide into metallic indium, mainly as a result of localized stress gradients caused by relaxation of the highly disordered indium sublattice in indium hydroxide. This partial decomposition of indium hydroxide into metallic indium is irreversible, as confirmed by angle-dispersive X-ray diffraction, transmission electron microscopy imaging, Raman scattering, and FTIR spectroscopy. Recovered c-In(OH)(3) samples become completely black and nontransparent and show typical features of metals, i.e., a falling absorption in the 100-250 cm(-1) region accompanied by a featureless spectrum in the 250-2500 cm(-1) region in the Raman spectrum and Drude-like absorption of free electrons in the region of 4000-8000 cm(-1) in the FTIR spectrum. These features were not observed in the initial c-In(OH)(3), which is a typical white wide-band-gap semiconductor.

  1. Pharmacokinetic Profile of Oral Magnesium Hydroxide.

    Science.gov (United States)

    Dolberg, Mette Konow Bøgebjerg; Nielsen, Lars Peter; Dahl, Ronald

    2017-03-01

    Despite the presumption of a beneficial effect of magnesium (Mg) supplementation on various diseases, little is known concerning the pharmacokinetics of Mg hydroxide. This study was designed to provide a pharmacokinetic profile of Mg hydroxide after a single oral dose. Ten healthy male adults participated in this cross-over study with three 24-hr study days. Interventions were (i) none (baseline), (ii) oral intake of three (3 × 360 mg) tablets of Mg hydroxide (Mablet ® ) and (iii) IV bolus infusion of 2 g Mg sulphate (index drug). Blood samples were collected before the single dose, after (i.e. after treatment administration) 15, 30, 60, 90 and 120 min. and after 3, 4, 6, 8, 12 and 24 hr. Urine was collected in four 6-hr periods per study day. Blood (N = 10) and urine (N = 6) Mg were analysed by descriptive statistics. Bioavailability was 14.9% (CI: 8.3; 26.8), blood clearance was 5.1 L/hr (CI: 2.1; 17.0), apparent volume of distribution was 60.2 L (CI: 35.6; 102.0), elimination constant was 0.08 per hour (CI: 0.05; 0.14), half-life was 8.3 hr (CI: 4.8; 14.1), C max was 0.11 mmol/L (CI: 0.07; 0.14), and AUC [0-24] was 92.3 mmol/L × min. (CI: 45.5; 139.1). Urine Mg excretion augmented by 17.7% (CI: 8.9; 35.0) from baseline. No severe side effects were observed. The bioavailability of Mg hydroxide was 15%, and it constitutes a clinically relevant option for oral Mg supplementation. No severe side effects were seen. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  2. Calcium hydroxide silylation reaction with trimethylchlorosilane

    Directory of Open Access Journals (Sweden)

    Novoselnov Anatoliy A.

    2016-01-01

    Full Text Available The silylation reaction of a calcium hydroxide with a trimethylchlorosilane is studied as a silylation model by the gas-liquid chromatography. The silylation process is divided into three stages. A material balance of these stages is calculated. The schemes of the reactions at each stage of the process are proposed. The modified calcium hydroxide obtained at three repetitive stages of the silylation reaction has been investigated by the x-ray phase analysis, IR spectroscopy, thermal analysis, electron microscopy in a combination with the elemental analysis. It has been determined that at the first stage of the interaction the processes of the trimethylchlorosilane hydrolysis and of the hydrolysis products condensation dominate, and at the same time an adsorption process of the trimethylchlorosilane and its derivatives starts. Further, the hydrolysis of the trimethylchlorosilane by the «new» portions of a water formed in the reaction of a calcium hydroxide with a hydrogen chloride takes place, simultaneously the secondary reactions of the Si-O-Ca – ties’ formation and cleavage occur including as a silylation-desilylation dynamic equilibrium process.

  3. Nickel hydroxide modified electrodes for urea determination

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Dall´Antonia

    2007-03-01

    Full Text Available Nickel hydroxide films were prepared by electrodeposition from a solution Ni(NO32 0,05 mol L ?¹ on ITO electrodes (Tin oxide doped with Indium on PET-like plastic film, applying a current of - 0,1 A cm ?² during different time intervals between 1800 and 7200 s. The electrochemical behavior of the nickel hydroxide electrode was investigated through a cyclic voltammogram, in NaOH 1,0 mol L ?¹, where it was observed two peaks in the profile in 0,410 and 0,280 V, corresponding to redox couple Ni(II/Ni(III. A sensor for urea presenting a satisfactory answer can be obtained when, after the deposit of the film of Ni(OH2 on the electrode of nickel, it is immersed in a solution of NaOH 1,0 mol L ?¹ and applying a potential of + 0,435 V, where the maximum of the anodic current occurs in the cyclic voltammogram. Analyzing the results it can be observed that, for a range of analite concentration between 5 to 50 m mol L ?¹, the behavior is linear and the sensibility found was of 20,3 mA cm?² (mol L?¹?¹, presenting reproducibility confirming the nickel hydroxide electrodes utilization for the determination of urea.

  4. Laser control and temperature switching of luminescence intensity in photostable transparent film based on terbium(III) β-diketonate complex

    Science.gov (United States)

    Lapaev, Dmitry V.; Nikiforov, Victor G.; Safiullin, Georgy M.; Lobkov, Vladimir S.; Salikhov, Kev M.; Knyazev, Andrey A.; Galyametdinov, Yury G.

    2014-11-01

    The study of the terbium(III) and gadolinium(III) β-diketonate complexes by photoluminescence spectroscopy reveals considerable changes of the photophysical properties of the complexes under the UV laser irradiation. The measurements show the enhancement of the luminescence intensities in the vitrified transparent film of the terbium(III) complex as well as the gadolinium(III) complex under the 337 nm laser irradiation at room temperature. The irradiated film of the terbium(III) complex restores the initial photophysical properties after heating close to the melting temperature (∼353 K) and cooling. We observe no change of the luminescent properties of the irradiated film for months. These features can be used for the design of new lanthanide-based photostable systems with laser control of the luminescence intensity.

  5. Nickel-cobalt hydroxide nanosheets: Synthesis, morphology and electrochemical properties.

    Science.gov (United States)

    Schneiderová, Barbora; Demel, Jan; Zhigunov, Alexander; Bohuslav, Jan; Tarábková, Hana; Janda, Pavel; Lang, Kamil

    2017-08-01

    This paper reports the synthesis, characterization, and electrochemical performance of nickel-cobalt hydroxide nanosheets. The hydroxide nanosheets of approximately 0.7nm thickness were prepared by delamination of layered nickel-cobalt hydroxide lactate in water and formed transparent colloids that were stable for months. The nanosheets were deposited on highly oriented pyrolytic graphite by spin coating, and their electrochemical behavior was investigated by cyclic voltammetry in potassium hydroxide electrolyte. Our method of electrode preparation allows for studying the electrochemistry of nanosheets where the majority of the active centers can participate in the charge transfer reaction. The observed electrochemical response was ascribed to mutual compensation of the cobalt and nickel response via electron sharing between these metals in the hydroxide nanosheets, a process that differentiates the behavior of nickel-cobalt hydroxide nanosheets from single nickel hydroxide or cobalt hydroxide nanosheets or their physical mixture. The presence of cobalt in the nickel-cobalt hydroxide nanosheets apparently decreases the time of electrochemical activation of the nanosheet layer, which for the nickel hydroxide nanosheets alone requires more potential sweeps. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Development of functionalized terbium fluorescent nanoparticles for antibody labeling and time-resolved fluoroimmunoassay application.

    Science.gov (United States)

    Ye, Zhiqiang; Tan, Mingqian; Wang, Guilan; Yuan, Jingli

    2005-01-15

    Silica-based functionalized terbium fluorescent nanoparticles were prepared, characterized and developed as a fluorescence probe for antibody labeling and time-resolved fluoroimmunoassay. The nanoparticles were prepared in a water-in-oil (W/O) microemulsion containing a strongly fluorescent Tb(3+) chelate, N,N,N(1),N(1)-[2,6-bis(3'-aminomethyl-1'-pyrazolyl)phenylpyridine] tetrakis(acetate)-Tb(3+) (BPTA-Tb(3+)), Triton X-100, octanol, and cyclohexane by controlling copolymerization of tetraethyl orthosilicate (TEOS) and 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane (AEPS) with ammonia water. The characterizations by transmission electron microscopy and fluorometric methods show that the nanoparticles are spherical and uniform in size, 45 +/- 3nm in diameter, strongly fluorescent with fluorescence quantum yield of 10% and a long fluorescence lifetime of 2.0ms. The amino groups directly introduced to the nanoparticle's surface by using AEPS in the preparation made the surface modification and bioconjugation of the nanoparticles easier. The nanoparticle-labeled anti-human alpha-fetoprotein antibody was prepared and used for time-resolved fluoroimmunoassay of alpha-fetoprotein (AFP) in human serum samples. The assay response is linear from 0.10ngml(-1) to about 100ngml(-1) with the detection limit of 0.10ngml(-1). The coefficient variations (CVs) of the method are less than 9.0%, and the recoveries are in the range of 84-98% for human serum sample measurements.

  7. 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.)

  8. A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    Salma M.Z. Al-Kindy

    2014-12-01

    Full Text Available A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex  = 285 nm and λem  = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7  M, Tween-20 (0.30% and 4Å~10-5  mol L-1  of Tb3+  which allowed the determination of 20–1000 ng mL-1  of FLP with a limit of detection (LOD of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%.

  9. Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hong; Yi Chongyue; Li Xue; Fang Fang [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang, E-mail: yjyang@mail.hust.edu.c [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-04-15

    Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)-PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)-PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)-PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)-PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)-PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)-PUFX to the DBS gels.

  10. A Nanoscale Multiresponsive Luminescent Sensor Based on a Terbium(III) Metal-Organic Framework.

    Science.gov (United States)

    Dang, Song; Wang, Ting; Yi, Feiyan; Liu, Qinghui; Yang, Weiting; Sun, Zhong-Ming

    2015-08-01

    A nanoscale terbium-containing metal-organic framework (nTbL), with a layer-like structure and [H2 NMe2 ](+) cations located in the framework channels, was synthesized under hydrothermal conditions. The structure of the as-prepared sample was systematically confirmed by powder XRD and elemental analysis; the morphology was characterized by field-emission SEM and TEM. The photoluminescence studies revealed that rod-like nTbL exhibited bright-green emission, corresponding to (5)D4 →(7)FJ (J=6-3) transitions of the Tb(3+) ion under excitation. Further sensing measurements revealed that as-prepared nTbL could be utilized as a multiresponsive luminescent sensor, which showed significant and exclusive detection ability for Fe(3+) ions and phenylmethanol. These results highlight the practical applications of lanthanide-containing metal-organic frameworks as fluorescent probes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Terbium-Doped VO2 Thin Films: Reduced Phase Transition Temperature and Largely Enhanced Luminous Transmittance.

    Science.gov (United States)

    Wang, Ning; Duchamp, Martial; Dunin-Borkowski, Rafal E; Liu, Shiyu; Zeng, XianTing; Cao, Xun; Long, Yi

    2016-01-26

    Vanadium dioxide (VO2) is a well-known thermochromic material with large IR modulating ability, promising for energy-saving smart windows. The main drawbacks of VO2 are its high phase transition temperature (τ(c) = 68°C), low luminous transmission (T(lum)), and weak solar modulating ability (ΔT(sol)). In this paper, the terbium cation (Tb(3+)) doping was first reported to reduce τ(c) and increase T(lum) of VO2 thin films. Compared with pristine VO2, 2 at. % doping level gives both enhanced T(lum) and ΔT(sol) from 45.8% to 54.0% and 7.7% to 8.3%, respectively. The T(lum) increases with continuous Tb(3+) doping and reaches 79.4% at 6 at. % doping level, representing ∼73.4% relative increment compared with pure VO2. This has surpassed the best reported doped VO2 thin films. The enhanced thermochromic properties is meaningful for smart window applications of VO2 materials.

  12. Luminescent investigations of terbium(III) biosorption as a surrogate for heavy metals and radionuclides.

    Science.gov (United States)

    Achyuthan, Komandoor E; Arango, Dulce C; Carles, Elizabeth L; Cutler, Christopher E; Meyer, Lauren A; Brozik, Susan M

    2009-07-01

    We describe a metal transport system for investigating the interfacial interactions between the anionic surface charge of a gram-negative bacterium (Escherichia coli) and a trivalent cationic metal, Tb3+. We believe this is the first description of the uptake kinetics, sub- and intracellular distribution, and temporal fate of Tb3+ ion in E. coli. We used the luminescence of the terbium-dipicolinic acid chelate to study metal ion transport. The bacteria had a high tolerance for the metal (IC(50) = 4 mM Tb3+). Metal ion transport was passive and metabolism independent. The uptake kinetics rapidly reached a maximum within 15 min, followed by a stasis for 60 min, and declining thereafter between 120 and 240 min, resulting in a biphasic curve. During this period, greater than one-third of the metal ion was sequestered within the cell. Our choice of a safe Biosafety Level I E. coli bacteria and the relatively non-toxic Tb3+ metal represents a model system for luminescent investigations of biosorption, for studying bacterial-water interfacial chemistry and for the bioremediation of heavy metals and radionuclides.

  13. Application of the SCC-DFTB method to hydroxide water clusters and aqueous hydroxide solutions.

    Science.gov (United States)

    Choi, Tae Hoon; Liang, Ruibin; Maupin, C Mark; Voth, Gregory A

    2013-05-02

    The self-consistent charge density functional tight binding (SCC-DFTB) method has been applied to hydroxide water clusters and a hydroxide ion in bulk water. To determine the impact of various implementations of SCC-DFTB on the energetics and dynamics of a hydroxide ion in gas phase and condensed phase, the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus, and DFTB3-3OB implementations have been tested. Energetic stabilities for small hydroxide clusters, OH(-)(H2O)n, where n = 4-7, are inconsistent with the results calculated with the B3LYP and second order Møller-Plesset (MP2) levels of ab initio theory. The condensed phase simulations, OH(-)(H2O)127, using the DFTB2, DFTB2-γ(h), DFTB2-γ(h)+gaus, DFTB3-diag, DFTB3-diag+gaus, DFTB3-Full+gaus and DFTB3-3OB methods are compared to Car-Parrinello molecular dynamics (CPMD) simulations using the BLYP functional. The SCC-DFTB method including a modified O-H repulsive potential and the third order correction (DFTB3-diag/Full+gaus) is shown to poorly reproduce the CPMD computational results, while the DFTB2 and DFTB2-γ(h) method somewhat more closely describe the structural and dynamical nature of the hydroxide ion in condensed phase. The DFTB3-3OB outperforms the MIO parameter set but is no more accurate than DFTB2. It is also shown that the overcoordinated water molecules lead to an incorrect bulk water density and result in unphysical water void formation. The results presented in this paper point to serious drawbacks for various DFTB extensions and corrections for a hydroxide ion in aqueous environments.

  14. Effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in horses.

    Science.gov (United States)

    Clark, C K; Merritt, A M; Burrow, J A; Steible, C K

    1996-05-15

    To assess the effect of aluminum hydroxide/magnesium hydroxide antacid and bismuth subsalicylate on gastric pH in clinically normal horses and to develop guidelines on the use of these agents for treatment of peptic ulcer disease in horses. Prospective, randomized, controlled trial. 5 clinically normal adult horses with chronically implanted gastric cannulas. Each horse received all 5 treatments (30 g of aluminum hydroxide/15 g of magnesium hydroxide, 12 g of aluminum hydroxide/6 g of magnesium hydroxide, 10.5 g of bismuth subsalicylate, 26.25 g of bismuth subsalicylate, and 5% methylcellulose control) with only 1 experiment performed each day. Gastric pH was measured via a glass electrode inserted through the gastric cannula for 1 hour before treatment and continued for 2 hours after treatment. Food or water was not given to the horses during the experiment. Measurements of gastric pH obtained during posttreatment hours were compared with pretreatment gastric pH values. Only a dose of 30 g of aluminum hydroxide/ 15 g of magnesium hydroxide resulted in a significant increase in gastric pH over baseline or control values. Mean pH was 5.2 +/- 0.62 and 4.59 +/- 0.48 for posttreatment hours 1 and 2, respectively. Oral administration of 30 g of aluminum hydroxide/15 g of magnesium hydroxide to adult horses should result in a mean hourly gastric pH > or = 4.0 for at least 2 hours.

  15. Antimicrobial activity of calcium hydroxide in endodontics: a review.

    Science.gov (United States)

    Mohammadi, Z; Shalavi, S; Yazdizadeh, M

    2012-12-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

  16. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    Science.gov (United States)

    Shalavi, S; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

  17. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    OpenAIRE

    Mohammadi, Z; Shalavi, S; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5...

  18. Construction of the energy matrix for complex atoms. Part VIII: Hyperfine structure HPC calculations for terbium atom

    Science.gov (United States)

    Elantkowska, Magdalena; Ruczkowski, Jarosław; Sikorski, Andrzej; Dembczyński, Jerzy

    2017-11-01

    A parametric analysis of the hyperfine structure (hfs) for the even parity configurations of atomic terbium (Tb I) is presented in this work. We introduce the complete set of 4fN-core states in our high-performance computing (HPC) calculations. For calculations of the huge hyperfine structure matrix, requiring approximately 5000 hours when run on a single CPU, we propose the methods utilizing a personal computer cluster or, alternatively a cluster of Microsoft Azure virtual machines (VM). These methods give a factor 12 performance boost, enabling the calculations to complete in an acceptable time.

  19. Aluminium hydroxide-induced granulomas in pigs

    DEFF Research Database (Denmark)

    Valtulini, S; Macchi, C; Ballanti, P

    2005-01-01

    in the muscles of the neck (group slaughtered). The pigs had been injected with a vaccine containing 40 mg/2 ml dose of aluminium hydroxide as adjuvant. Research consisted of two phases: first, an epidemiological study was carried out, aimed at determining the risk factors for the granulomas. The results...... indicated that the vaccine was to be held responsible for the formation of granulomas. A clinical trial was then performed to further substantiate the initial hypothesis, by comparing pigs, which were aseptically inoculated twice with either the original vaccine or the adjuvant alone (groups vaccine...... was the cause of the granulomas....

  20. Spectrofluorimetric determination of human serum albumin using terbium-danofloxacin probe.

    Science.gov (United States)

    Ramezani, Amir M; Manzoori, Jamshid L; Amjadi, Mohammad; Jouyban, Abolghasem

    2012-01-01

    A spectrofluorimetric method is proposed for the determination of human serum albumin (HSA) and bovine serum albumin (BSA) using terbium-danofloxacin (Tb(3+)-Dano) as a fluorescent probe. These proteins remarkably enhance the fluorescence intensity of the Tb(3+)-Dano complex at 545 nm, and the enhanced fluorescence intensity of Tb(3+)-Dano is proportional to the concentration of proteins (HSA and BSA). Optimum conditions for the determination of HSA were investigated and found that the maximum response was observed at: pH = 7.8, [Tb(3+)] = 8.5 × 10(-5) mol L(-1), [Dano] = 1.5 × 10(-4) mol L(-1). The calibration graphs for standard solutions of BSA, HSA, and plasma samples of HSA were linear in the range of 0.2 × 10(-6) - 1.3 × 10(-6) mol L(-1), 0.2 × 10(-6) - 1.4 × 10(-6) mol L(-1), and 0.2 × 10(-6) - 1 × 10(-6) mol L(-1), respectively. The detection limits (S/N = 3) for BSA, HSA, and plasma sample of HSA were 8.7 × 10(-8) mol L(-1), 6.2 × 10(-8) mol L(-1), and 8.1 × 10(-8) mol L(-1), respectively. The applicability of the method was checked using a number of real biological plasma samples and was compared with the UV spectrometric reference method. The results was showed that the method could be regarded as a simple, practical, and sensitive alternative method for determination of albumin in biological samples.

  1. Spectrofluorimetric Determination of Human Serum Albumin Using Terbium-Danofloxacin Probe

    Directory of Open Access Journals (Sweden)

    Amir M. Ramezani

    2012-01-01

    Full Text Available A spectrofluorimetric method is proposed for the determination of human serum albumin (HSA and bovine serum albumin (BSA using terbium-danofloxacin (Tb3+-Dano as a fluorescent probe. These proteins remarkably enhance the fluorescence intensity of the Tb3+-Dano complex at 545 nm, and the enhanced fluorescence intensity of Tb3+-Dano is proportional to the concentration of proteins (HSA and BSA. Optimum conditions for the determination of HSA were investigated and found that the maximum response was observed at: pH=7.8, [Tb3+] =8.5×10−5 mol L−1, [Dano] =1.5×10−4 mol L−1. The calibration graphs for standard solutions of BSA, HSA, and plasma samples of HSA were linear in the range of 0.2×10−6−1.3×10−6 mol L−1, 0.2×10−6−1.4×10−6 mol L−1, and 0.2×10−6−1×10−6 mol L−1, respectively. The detection limits (S/N = 3 for BSA, HSA, and plasma sample of HSA were 8.7×10−8 mol L−1, 6.2×10−8 mol L−1, and 8.1×10−8 mol L−1, respectively. The applicability of the method was checked using a number of real biological plasma samples and was compared with the UV spectrometric reference method. The results was showed that the method could be regarded as a simple, practical, and sensitive alternative method for determination of albumin in biological samples.

  2. Determination of flavonoids in pharmaceutical preparations using Terbium sensitized fluorescence method

    Directory of Open Access Journals (Sweden)

    M Shaghaghi

    2009-12-01

    Full Text Available "nBackground and the Purpose of the Study: The aim of this study was development and validation of a simple, rapid and sensitive spectrofluorimetric method for determination of total flavonoids in two topical formulations of Calendula officinalis, Ziziphus Spina-christi and an oral drop of Hypiran perforatum L. The proposed method is based on the formation of terbium (Tb3+ "n-flavonoids (quercetin as a reference standard complex at pH 7.0, which has fluorescence intensely with maximum emission at 545 nm when excited at 310 nm. "nMethod "n: For ointments masses of topical formulations were weighed and added to ethanol-aqueous buffer (pH 10.0 and the resulting mixtures were shaken and then two phases were separated by centrifugation. Aqueous phases were filtered and then diluted with water. For Hypiran drops an appropriate portion was diluted with ethanol and then aliquots of sample or standard solutions were determined according to the experimental procedure. "nResults "n: Under the optimum conditions, total concentrations of flavonoids (as quercetin equivalent in three tested formulations were found to be 0.204 mg/g (for Dermatin cream, 0.476 mg/g (for Calendula ointment and 13.50 μg/ml (for Hypiran drops. Analytical recoveries from samples spiked with different amounts of quercetin were 96.1-104.0 % with RSD % of less than 3.5. Conclusion : The proposed method which requires a simple dissolution step without any matrix interferences provided high sensitivity and selectivity and was easily applied to determine total flavonoids in real samples of three investigated formulations with excellent reproducibility.

  3. 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.

  4. Particle size and shape of calcium hydroxide.

    Science.gov (United States)

    Komabayashi, Takashi; D'souza, Rena N; Dechow, Paul C; Safavi, Kamran E; Spångberg, Larz S W

    2009-02-01

    The aim of this study was to examine the particle length, width, perimeter, and aspect ratio of calcium hydroxide powder using a flow particle image analyzer (FPIA). Five sample groups each with 10 mg of calcium hydroxide were mixed with 15 mL of alcohol and sonicated. Digital images of the particle samples were taken using the FPIA and analyzed with a one-way analysis of variance. The overall averages +/- standard deviation among the five groups for particle length (microm), width (microm), perimeter (microm), and aspect ratio were 2.255 +/- 1.994, 1.620 +/- 1.464, 6.699 +/- 5.598, and 0.737 +/- 0.149, respectively. No statistical significance was observed among the groups for all parameters. When the total of 46,818 particles from all five groups were classified into the five length categories of 0.5-microm increments, there were significant differences in width, perimeter, and aspect ratio (all p values particles have a size and shape that may allow direct penetration into open dentin tubules.

  5. 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

  6. Zinc sulfide and terbium-doped zinc sulfide films grown by traveling wave reactor atomic layer epitaxy

    CERN Document Server

    Yun, S J; Nam, K S

    1998-01-01

    Zinc sulfide (ZnS) and terbium-doped ZnS (ZnS:Tb) thin films were grown by traveling wave reactor atomic layer epitaxy (ALE). In the present work, ZnCl sub 2 , H sub 2 S, and tris (2,2,6,6-tetramethyl-3,5-heptandionato) terbium (Tb(tmhd) sub 3) were used as the precursors. The dependence of crystallinity and Cl content of ZnS films was investigated on the growth temperature. ZnS and ZnS:Tb films grown at temperatures ranging from 400 to 500 .deg. C showed a hexagonal-2H crystalline structure. The crystallinity of ZnS film was greatly enhanced as the temperature increased. At growth temperatures higher than 450.deg.C, the films showed preferred orientation with mainly (002) diffraction peak. The Cl content decreased from approximately 9 to 1 at.% with the increase in growth temperature from 400 to 500 .deg. C. The segregation of Cl near the surface region and the incorporation of O from Tb(tmhd) sub 3 during ALE process were also observed using Auger electron spectroscopy. The ALE-grown ZnS and ZnS:Tb films re...

  7. Commercializing potassium terbium fluoride, KTF (KTb3F10) faraday crystals for high laser power optical isolator applications

    Science.gov (United States)

    Schlichting, Wolfgang; Stevens, Kevin; Foundos, Greg; Payne, Alexis

    2017-10-01

    Many scientific lasers and increasingly industrial laser systems operate in power regime, require high-performance optical isolators to prevent disruptive light feedback into the laser cavity. The optically active Faraday material is the key optical element inside the isolator. SYNOPTICS has been supplying the laser market with Terbium Gallium Garnet (TGG - Tb3Ga5O12) for many years. It is the most commonly used material for the 650-1100nm range and the key advantages for TGG include its cubic crystal structure for alignment free processing, little to no intrinsic birefringence, and ease of manufacture. However, for high-power laser applications TGG is limited by its absorption at 1064nm and its thermo-optic coefficient, dn/dT. Specifically, thermal lensing and depolarization effects become a limiting factor at high laser powers. While TGG absorption has improved significantly over the past few years, there is an intrinsic limit. Now, SYNOPTICS is commercializing the enhanced new crystal Potassium Terbium Fluoride KTF (KTb3F10) that exhibits much smaller nonlinear refractive index and thermo-optic coefficients, and still exhibits a Verdet constant near that of TGG. This cubic crystal has relatively low absorption and thermo-optic coefficients. It is now fully characterized and available for select production orders. At OPTIFAB in October 2017 we present recent results comparing the performance of KTF to TGG in optical isolators and show SYNOPTICS advances in large volume crystal growth and the production ramp up.

  8. Preparation and photoluminescence enhancement in terbium(III ternary complexes with β-diketone and monodentate auxiliary ligands

    Directory of Open Access Journals (Sweden)

    Devender Singh

    2016-12-01

    Full Text Available A series of new solid ternary complexes of terbium(III ion based on β-diketone ligand acetylacetone (acac and monodentate auxiliary ligands (aqua/urea/triphenylphosphineoxide/pyridine-N-oxide had been prepared. The structural characterizations of synthesized ternary compounds were studied by means of elemental analysis, infrared (IR, and proton nuclear magnetic resonance (NMR spectral techniques. The optical characteristics were investigated with absorption as well as photoluminescence spectroscopy. Thermal behavior of compounds was examined by TGA/DTA analysis and all metal complexes were found to have good thermal stability. The luminescence decay time of complexes were also calculated by monitoring at emission wavelength corresponding to 5D4 → 7F5 transition. A comparative inspection of the luminescent behavior of prepared ternary compounds was performed in order to determine the function of auxiliary ligands in the enhancement of luminescence intensity produced by central terbium(III ion. The color coordinates values suggested that compounds showed bright green emission in visible region in electromagnetic spectrum. Complexes producing green light could play a significant role in the fabrication of efficient light conversion molecular devices for display purposes and lightning systems.

  9. Acid mine water neutralisation with ammonium hydroxide and ...

    African Journals Online (AJOL)

    This study showed that NH4OH can be used for treatment of acid mine drainage rich in sulphates and NH4OH can be recycled in the process. Hydrated lime treatment resulted in removal of the remaining ammonia using a rotary evaporator. Keywords: acid mine water, ammonium hydroxide, barium hydroxide, sulphate ...

  10. Hydroxide Solvation and Transport in Anion Exchange Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen [Univ. of Chicago, IL (United States); Wuhan Univ. (China); Tse, Ying-Lung Steve [Univ. of Chicago, IL (United States); Lindberg, Gerrick E. [Northern Arizona Univ., Flagstaff, AZ (United States); Knight, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Voth, Gregory A. [Univ. of Chicago, IL (United States)

    2016-01-27

    Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

  11. Hydroxide depletion in dilute supernates stored in waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1985-10-10

    Free hydroxide ion in dilute supernates are depleted by reaction with atmospheric carbon dioxide to form bicarbonate and carbonate species and by reaction with acidic compounds formed by the radiolytic decomposition of tetraphenylborate salts. A model of the kinetics and thermodynamics of absorption of carbon dioxide in the waste tanks has been developed. Forecasts of the rate of hydroxide depletion and the requirements for sodium hydroxide to maintain technical standards have been made for the washed sludge and washed precipitate storage tanks. Hydroxide depletion is predicted to have a minimal impact on sludge processing operations. However, in-tank precipitation and downstream DWPF operations are predicted to be significantly affected by hydroxide depletion in Tank 49H. The installation of a carbon dioxide scrubber on Tank 49H may be justified in view of the decrease in alkali content and variation in the melter feed.

  12. Paradoxical hypomagnesemia caused by excessive ingestion of magnesium hydroxide.

    Science.gov (United States)

    Joo Suk, Oh

    2008-09-01

    Excessive ingestion of magnesium may lead to hypermagnesemia even without kidney dysfunction. Several cases of development of hypermagnesemia after overdose of magnesium hydroxide have been reported. Although magnesium hydroxide is widely used as laxative, its overdose may induce diarrhea, which is followed by excessive magnesium loss. I report a case of paradoxical hypomagnesemia developed after excessive ingestion of magnesium hydroxide. A 39-year-old woman was presented to the emergency department complaining of severe watery diarrhea and carpopedal spasm after ingesting a handful of magnesium hydroxide tablets. The laboratory tests detected hypomagnesemia, hypocalcemia, and normokalemia. Calcium gluconate was given to the patient, but her symptom did not improve shortly. The symptom disappeared spontaneously 2 days after the watery diarrhea subsided. This case shows that overdose of magnesium hydroxide, which leads to massive diarrhea, might induce hypomagnesemia unexpectedly. This case also suggests that it should be treated, as well as typical magnesium deficiency.

  13. Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: quasi-elastic light scattering studies.

    Science.gov (United States)

    Guterman, L R; Falzone, J; Wilson, G E

    1986-05-01

    The effects of hydrochloric acid on mixed gels of aluminum and magnesium hydroxide and on magaldrate have been examined using quasi-elastic light scattering. Particles of magaldrate and mixed gels behave differently. The magaldrate particles initially decrease in size in response to increasing amounts of hydrochloric acid up to that sufficient to neutralize all the magnesium hydroxide present, then increase in size to approximately 2 microns. The composition of the mixed gels appears to be particularly important in determining the reaction with limited amounts of acid. For these particles, which are thought to consist of a magnesium hydroxide core surrounded by an aluminum hydroxide sheath, slow erosion of the aluminum hydroxide was apparently followed by complete disintegration of the particles. Particles which remain grow in size to approximately 3 microns.

  14. Synthesis and luminescent study of Ce{sup 3+}-doped terbium-yttrium aluminum garnet

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, V.P., E-mail: ssclab@ukr.net [A.V. Bogatsky Physico-Chemical Institute, National Academy of Sciences of Ukraine, Lustdorfskaya doroga 86, 65080 Odessa (Ukraine); Berezovskaya, I.V.; Zubar, E.V.; Efryushina, N.P. [A.V. Bogatsky Physico-Chemical Institute, National Academy of Sciences of Ukraine, Lustdorfskaya doroga 86, 65080 Odessa (Ukraine); Poletaev, N.I.; Doroshenko, Yu.A. [Institute of Combustion and Advanced Technologies, Mechnikov Odessa National University, Dvoryanskaya 2, 65082 Odessa (Ukraine); Stryganyuk, G.B. [Ivan Franko National University of Lviv, Kirilo i Mefodii 8, 79005 Lviv (Ukraine); HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg (Germany); Voloshinovskii, A.S. [Ivan Franko National University of Lviv, Kirilo i Mefodii 8, 79005 Lviv (Ukraine)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer Ce{sup 3+}-doped garnets (TYAG) were prepared using nanostructured reagents. Black-Right-Pointing-Pointer The Ce{sup 3+} ions cause a very efficient yellow emission of the samples. Black-Right-Pointing-Pointer The reasons for the long wavelength position of this emission are discussed. Black-Right-Pointing-Pointer Contribution from Al atoms to the conduction band of TYAG is quite essential. - Abstract: Terbium-yttrium aluminum garnets (TYAG) doped with Ce{sup 3+} ions have been prepared by solid state reactions between nanostructured oxides of aluminum and rare earths. The luminescent properties of Ce{sup 3+} ions in (Tb{sub 0.8}Y{sub 0.2}){sub 3(1-x)}Ce{sub 3x}Al{sub 5}O{sub 12} (x = 0.03) have been studied upon excitation in the 2-20 eV region. The substitution of Tb{sup 3+} for Y{sup 3+} in the garnet structure results in broadening the emission band and shifting its maximum towards the longer wavelengths. It was found that in addition to the 4f{sup n} {yields} 4f{sup n-1}5d excitation bands of Ce{sup 3+} and Tb{sup 3+} ions, the excitation spectra for the Ce{sup 3+} emission contain broad bands at 6.73 and {approx}9.5 eV. These bands are attributed to the Ce{sup 3+}-bound exciton formation and O 2p {yields} Al 3s, 3p transitions, respectively. In contrast to the predictions based on the results of electronic structure calculations on Y{sub 3}Al{sub 5}O{sub 12} and Tb{sub 4}Al{sub 2}O{sub 9}, the threshold of interband transitions in TYAG is at high energies ( Greater-Than-Or-Slanted-Equal-To 7.3 eV), and contributions from Al{sub tetr} and Al{sub oct} atoms to the conduction-band density of states are evaluated as quite essential.

  15. The study of processes of iron hydroxide coagulation and sedimentation

    Science.gov (United States)

    Fedorova, A. S.; Nedobukh, T. A.; Mashkovtsev, M. A.; Semenishchev, V. S.

    2017-09-01

    Migration behavior of radionuclides forming pseudoradiocolloids with iron hydroxide depends on physicochemical behavior of iron hydroxide. It was determined that pH of the solution and iron concentration are the main parameters affecting processes coagulation and sedimentation of iron hydroxide. Time dependences of iron hydroxide coagulation and sedimentation being obtained using ultrafiltration and turbidimetry methods were analyzed. Integral and differential curves of size distribution of iron hydroxide particles were obtained using the method of laser diffraction. At the whole pH range studied, monomodal size distribution was observed in the solution containing 25 mg L-1 of iron; whereas in the solution containing 100 mg L-1 of iron bimodal size distribution was observed. This difference indicates different mechanisms of coagulation that was additionally confirmed by analysis of kinetic curves. It was found that the best conditions for formation and further sedimentation of iron hydroxide were pH 6-8 and iron concentration of at least 50 mg L-1. At these conditions, the time of half-precipitation of the iron hydroxide precipitate did not exceed five minutes.

  16. Structural variations in terbium(III) complexes with 1,3-adamantanedicarboxylate and diverse co-ligands

    Energy Technology Data Exchange (ETDEWEB)

    Thuéry, Pierre, E-mail: pierre.thuery@cea.fr

    2015-07-15

    Terbium nitrate was reacted with 1,3-adamantanedicarboxylic acid (LH{sub 2}) under solvo-hydrothermal conditions with either N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMA) as organic solvents. Hydrolysation of the latter co-solvents resulted in the formation of formate or acetate ions, which are present as co-ligands in the 1D coordination polymer [Tb(L)(HCOO)(H{sub 2}O){sub 2}] (1) and the 2D assembly [Tb(L)(CH{sub 3}COO)(H{sub 2}O)] (2). The increase in dimensionality in the latter arises from the higher connectivity provided by acetate versus formate, the L{sup 2−} ligand being bis-chelating in both cases. The complex [Tb{sub 2}(L){sub 3}(H{sub 2}O){sub 5}][Tb{sub 2}(L){sub 3}(H{sub 2}O){sub 4}]·3H{sub 2}O (3), another 1D species, crystallizes alongside crystals of 2. Further addition of cucurbit[6]uril (CB6), with DMF as co-solvent, gave the two complexes [Tb{sub 2}(L){sub 2}(CB6)(H{sub 2}O){sub 6}](NO{sub 3}){sub 2}·6H{sub 2}O (4) and [H{sub 2}NMe{sub 2}]{sub 2}[Tb(L)(HCOO){sub 2}]{sub 2}·CB6·3H{sub 2}O (5). Complex 4 crystallizes as a 3D framework in which Tb(L){sup +} chains are connected by tetradentate CB6 molecules, while 5 unites a carboxylate-bridged anionic 2D planar assembly and layers of CB6 molecules with counter-cations held at both portals. - Graphical abstract: One- to three-dimensional assemblies are formed in terbium(III) complexes with 1,3-adamantanedicarboxylate obtained under solvo-hydrothermal conditions, these species including formate or acetate co-ligands formed in situ, or additional cucurbit[6]uril molecules. - Highlights: • We report structures of terbium(III) complexes with 1,3-adamantanedicarboxylate. • Solvents able to generate co-ligands or counter-ions in situ have been used. • A 3D species including additional cucurbituril molecules is decribed. • One species displays an alternation of metal–organic and organic sheets.

  17. Aspects of Solvent Chemistry for Calcium Hydroxide Medicaments

    Directory of Open Access Journals (Sweden)

    Basil Athanassiadis

    2017-10-01

    Full Text Available Calcium hydroxide pastes have been used in endodontics since 1947. Most current calcium hydroxide endodontic pastes use water as the vehicle, which limits the dissolution of calcium hydroxide that can be achieved and, thereby, the maximum pH that can be achieved within the root canal system. Using polyethylene glycol as a solvent, rather than water, can achieve an increase in hydroxyl ions release compared to water or saline. By adopting non-aqueous solvents such as the polyethylene glycols (PEG, greater dissolution and faster hydroxyl ion release can be achieved, leading to enhanced antimicrobial actions, and other improvements in performance and biocompatibility.

  18. Complete Stokes polarimetry of magneto-optical Faraday effect in a terbium gallium garnet crystal at cryogenic temperatures.

    Science.gov (United States)

    Majeed, Hassaan; Shaheen, Amrozia; Anwar, Muhammad Sabieh

    2013-10-21

    We report the complete determination of the polarization changes caused in linearly polarized incident light due to propagation in a magneto-optically active terbium gallium garnet (TGG) single crystal, at temperatures ranging from 6.3 to 300 K. A 28-fold increase in the Verdet constant of the TGG crystal is seen as its temperature decreases to 6.3 K. In contrast with polarimetry of light emerging from a Faraday material at room temperature, polarimetry at cryogenic temperatures cannot be carried out using the conventional fixed polarizer-analyzer technique because the assumption that ellipticity is negligible becomes increasingly invalid as temperature is lowered. It is shown that complete determination of light polarization in such a case requires the determination of its Stokes parameters, otherwise inaccurate measurements will result with negative implications for practical devices.

  19. Development of Optical Isolators for Visible Light Using Terbium Aluminum Garnet (Tb3Al5O12) Single Crystals

    Science.gov (United States)

    Geho, Mikio; Takagi, Takashi; Chiku, Shinichiro; Fujii, Takashi

    2005-07-01

    We have recently reported the successful growth of incongruently melting terbium aluminum garnet (Tb3Al5O12; TAG) single crystals by the hybrid laser FZ (floating zone) method. Optical property evaluations confirmed a high transmittance and a larger Verdet constant than conventional Tb3Ga5O12 (TGG) crystals and/or Faraday glasses. In this study, we attempted to design, fabricate, and evaluate optical isolators in visible light through near-infrared (NIR) regions using TAG crystals. A finite element method (FEM) simulation of possible models led us to the preferable one based on a radially magnetized magnet. To realize this, we employed a pseudo-radially magnetized magnet. The target wavelengths of the prototype device were 408, 808, and 1064 nm. The typical extinction ratio was more than 30 dB and the insertion loss was less than 0.3 dB for AR-coated devices.

  20. Homogeneous Precipitation of Nickel Hydroxide Powders

    Energy Technology Data Exchange (ETDEWEB)

    Mavis, Bora [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    Precipitation and characterization of nickel hydroxide powders were investigated. A comprehensive precipitation model incorporating the metal ion hydrolysis, complexation and precipitation reactions was developed for the production of the powders with urea precipitation method. Model predictions on Ni2+ precipitation rate were confirmed with precipitation experiments carried out at 90 C. Experimental data and model predictions were in remarkable agreement. Uncertainty in the solubility product data of nickel hydroxides was found to be the large contributor to the error. There were demonstrable compositional variations across the particle cross-sections and the growth mechanism was determined to be the aggregation of primary crystallites. This implied that there is a change in the intercalate chemistry of the primary crystallites with digestion time. Predicted changes in the concentrations of simple and complex ions in the solution support the proposed mechanism. The comprehensive set of hydrolysis reactions used in the model described above allows the investigation of other systems provided that accurate reaction constants are available. the fact that transition metal ions like Ni2+ form strong complexes with ammonia presents a challenge in the full recovery of the Ni2+. On the other hand, presence of Al3+ facilitates the complete precipitation of Ni2+ in about 3 hours of digestion. A challenge in their predictive modeling studies had been the fact that simultaneous incorporation of more than one metal ion necessitates a different approach than just using the equilibrium constants of hydrolysis, complexation and precipitation reactions. Another limitation of using equilibrium constants is that the nucleation stage of digestion, which is controlled mainly by kinetics, is not fully justified. A new program released by IBM Almaden Research Center (Chemical Kinetics Simulator™, Version 1.01) lets the user change

  1. Synthesis of beta alumina from aluminum hydroxide and oxyhydroxide precursors

    CSIR Research Space (South Africa)

    Van Zyl, A

    1993-02-01

    Full Text Available Two aluminium oxyhydroxides, boehmite and pseudoboehmite, and two aluminium hydroxides, bayerite and gibbsite, have been investigated as precursors for the synthesis of the solid electrolyte, beta alumina. Reaction pathways and products have been...

  2. Conversion coatings prepared or treated with calcium hydroxide solutions

    Science.gov (United States)

    Minevski, Zoran (Inventor); Clarke, Eric (Inventor); Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor)

    2002-01-01

    A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

  3. Precipitation and aging of magnesium hydroxide before suspension polymerisation

    OpenAIRE

    Skoglund, Therese

    2005-01-01

    A colloid of magnesium hydroxide is used to stabilize droplets of monomers before suspension polymerisation. The characteristics of precipitated magnesium hydroxide changes significantly during the first hours. The viscosity is high and flucctuating at first but decreases and becomes low and stable after a few hours. When the colloid ages the primary particles agglomerate into larger particles which increases in size by time due to, among other things, Oswald ripening and aggregation. This ca...

  4. Molecular dynamics simulation of layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    KALINICHEV,ANDREY G.; WANG,JIANWEI; KIRKPATRICK,R. JAMES; CYGAN,RANDALL T.

    2000-05-19

    The interlayer structure and the dynamics of Cl{sup {minus}} ions and H{sub 2}O molecules in the interlayer space of two typical LDH [Layered Double Hydroxide] phases were investigated by molecular dynamics computer simulations. The simulations of hydrocalumite, [Ca{sub 2}Al(OH){sub 6}]Cl{center_dot}2H{sub 2}O reveal significant dynamic disorder in the orientations of interlayer water molecules. The hydration energy of hydrotalcite, [Mg{sub 2}Al(0H){sub 6}]Cl{center_dot}nH{sub 2}O, is found to have a minimum at approximately n = 2, in good agreement with experiment. The calculated diffusion coefficient of Cl{sup {minus}} as an outer-sphere surface complex is almost three times that of inner-sphere Cl{sup {minus}}, but is still about an order of magnitude less than that of Cl{sup {minus}} in bulk solution. The simulations demonstrate unique capabilities of combined NMR and molecular dynamics studies to understand the structure and dynamics of surface and interlayer species in mineral/water systems.

  5. [Preparation and characterization of zirconium hydroxide powder for fluoride adsorption].

    Science.gov (United States)

    Yang, Shuo; Dou, Xiao-min; Liang, Wen-yan; Wang, Yi-li; Lin, Wei

    2010-07-01

    The method co-precipitation was applied to preparation the zirconium hydroxide as a type drinking-water defluoridation adsorbent. The effect of the preparation conditions on the adsorptive capacity was studied. The optimization of preparation condition for zirconium hydroxide concludes that co-precipitation time is 10 h, pH value is 7.0, drying time is 72 h, calcination temperature is below 100 degrees C. Also, the adsorbent samples were characterized. SEM measurements reveal that zirconium hydroxide powder are constructed by several small particles, with a diameter about 20-30 microm. XRD and TG/DTA measurements show that the zirconium hydroxide samples have amorphous phase and converse to tetragonal phase when calcined at 600 degrees C. Nitrogen adsorption/desorption measurements show that samples have large surface areas of 138.4 m2/g and a 2 nm average pore size distribution in the mesopore region. The performance of zirconium hydroxide regeneration process was investigated. The results show that the regeneration techniques are very suitable to restore the fluorine-removal ability for zirconium hydroxide.

  6. A hydrometallurgical process for the recovery of terbium from fluorescent lamps: Experimental design, optimization of acid leaching process and process analysis.

    Science.gov (United States)

    Innocenzi, Valentina; Ippolito, Nicolò Maria; De Michelis, Ida; Medici, Franco; Vegliò, Francesco

    2016-12-15

    Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Layered zinc hydroxide salts: delamination, preferred orientation of hydroxide lamellae, and formation of ZnO nanodiscs.

    Science.gov (United States)

    Demel, Jan; Pleštil, Josef; Bezdička, Petr; Janda, Pavel; Klementová, Mariana; Lang, Kamil

    2011-08-15

    Delamination of layered zinc hydroxide salts (LZH) into hydroxide layers provides nanobuilding blocs of a two-dimensional anisotropy. The methodology, extent of delamination, the size and stability of hydroxide lamellae are described in detail. The ability of lamellae to restack to form oriented hydroxide films depends on the solvent, original LZH salt, and conditions used for delamination. The most interesting results were obtained using LZH intercalated with dodecyl sulfate anions and LZH nitrate delaminated in butanol at 60 °C and in formamide at room temperature, respectively. The former method produces hydroxide lamellae of a lateral size of ca. 10-20 nm. The inner structure of the hydroxide layers is conserved and separated lamellae restack to the original layered structure of LZH dodecyl sulfate. The latter method yields lamellae with a size decreasing from 73.3 nm to 10 nm after a 2-week aging, while their thickness is nearly constant (2.6-3.8 nm). However, the use of formamide is complicated by the formation of Zn(II) formate. The major part of LZH intercalated with dodecyl sulfate anions is transformed during the delamination procedure to anisotropic ZnO nanoparticles, either needle-like particles prolonged in the [0 0 1] direction or disc-like particles flattened along the (0 0 1) plane. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. The Effects of Aluminium Hydroxide and Magnesium Hydroxide on the Mechanical Properties of Thermoplastic Polyurethane Materials

    Directory of Open Access Journals (Sweden)

    Erkin Akdoğan

    2015-12-01

    Full Text Available Thermoplastic polyurethane materials are widely used in automotive, clothing, electrical and electronics, medical, construction, machine industry due to excellent physical and chemical properties. Thermoplastic polyurethane materials combustion and resistance to high temperature characteristics are poor. Additives and fillers are added into the polyurethane matrix to improve those properties. Particularly adding these agents as a flame retardant are affect mechanical properties of polyurethane materials. Therefore, it is important to determinate the mechanical properties of these materials. In this study, 5% by weight of the thermoplastic polyurethane material, aluminium tri hydroxide (ATH, (Al2O3 3H2O and magnesium hydroxide (MgOH, (Mg(OH2 were added. Ammonium polyphosphate (APP as an intumescent flame retardant with inorganic flame retardants were added to increase the flame resistance of produced composite structure. Tensile test, tear test, hardness and Izod impact tests were made and compared of those produced composites. As a result of experiments the addition of ATH has lowered the tensile strength and tear strength contrast to this the addition of MgOH has improved those properties. Hardness and Izod impact test results were showed that both of the additives have no negative effect.

  9. Investigation of the luminescent properties of terbium-anthranilate complexes and application to the determination of anthranilic acid derivatives in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, N.; Georges, J

    2003-01-10

    The luminescent properties of terbium complexes with furosemide (FR), flufenamic (FF) acid, tolfenamic (TF) acid and mefenamic (MF) acid have been investigated in aqueous solutions. For all four compounds, complexation occurs when the carboxylic acid of the aminobenzoic group is dissociated and is greatly favoured in the presence of trioctylphosphine oxide as co-ligand and Triton X-100 as surfactant. Under optimum conditions, luminescence of the lanthanide ion is efficiently sensitised and the lifetime of the {sup 5}D{sub 4} resonance level of terbium in the complex is ranging between 1 and 1.9 ms, against 0.4 ms for the aqua ion. The sensitivity of the method for the determination of anthranilic acid derivatives is improved by one to two orders of magnitude with respect to that achieved using native fluorescence or terbium-sensitised luminescence in methanol. The limits of detection are 2x10{sup -10}, 5x10{sup -10} and 2x10{sup -9} mol l{sup -1} for flufenamic acid, furosemide and tolfenamic acid, and mefenamic acid, respectively, with within-run RSD values of less than 1%. The method has been applied to the determination of flufenamic acid in spiked calf sera with and without sample pretreatment. Depending on the method and the analyte concentration, the recovery was ranging between 83 and 113% and the lowest concentration attainable in serum samples was close to 1x10{sup -7} mol l{sup -1}.

  10. EFFICACY OF DIFFERENT ENDODONTIC IRRIGATION PROTOCOLS IN CALCIUM HYDROXIDE REMOVAL

    Directory of Open Access Journals (Sweden)

    Elka N. Radeva

    2016-10-01

    Full Text Available Introduction: Calcium hydroxide is widely used in the field of endodontics as a temporary root canal filling. This medicament significantly increases pH and optimizes the treatment outcome. Its total removal before final obturation is very important. Otherwise it could affect the hermetic filling and respectively the endodontic success. Aim: To evaluate the most effective irrigation protocol of calcium hydroxide removal from root canals. Materials and methods: In this study 36 single root canal teeth were observed. They were randomly divided into three groups (n=10 each group according to the technique applied for calcium hydroxide removal - manual irrigation, irrigation and Revo-S rotary instrumentation; and passive ultrasonic irrigation, and a control group (n=6 – irrigation with distilled water only. After calcium hydroxide removals following the procedures above, teeth were separated longitudinally in a buccal-lingual direction and remnants of medicaments were observed in the apical, middle and coronal part of each tooth. Then all of the specimens were observed using scanning electron microscopy and evaluated by a specified scale. The results have undergone statistical analysis. Results: In the case of calcium hydroxide in the apex and in the middle with highest average is Revo-S, followed by Ultrasonic and irrigation. In the coronal part the highest average belongs to Revo-S, irrigation and Ultrasonic. In all groups the highest average is represented by control group. Conclusion: There is not a universal technique for removal of intracanal medicaments and applying more than one protocol is required.

  11. Preparation of aluminum hydroxide by recycling of aluminum dross

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung-Kyu; Lee, Hoo-In; Kim, Joon-Soo [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea)

    2001-10-31

    Aluminum dross should be recycled in consideration of characteristics of the dross and its reutilization after processing. In this study, aluminum dross generated in the domestic secondary aluminum industry was processed to use it as raw material for producing aluminum hydroxide. Sample dross was classified according to its size. The dross smaller than 850 {mu}m was leached with sodium hydroxide solution to extract the remaining aluminum from the dross into the solution, and then aluminum hydroxide precipitate was recovered from the leach liquor. Purity of the obtained aluminum hydroxide was above 98%, and size of the sample was in range of 3-39 {mu}m. Recovery of aluminum hydroxide precipitate was highest on condition that A/C ratio of the solution was 0.5 and pulp density was 14-16% at the leaching step. From the result, it was suggested that this process could be applicable to recycling of aluminum dross. (author). 8 refs., 5 tabs., 9 figs.

  12. Use of calcium hydroxide in deep cavities of primary teeth.

    Science.gov (United States)

    Fernandes, Jocianelle Maria; Massoni, Andreza Cristina; Ferreira, Jainara Maria; Menezes, Valdenice Aparecida

    2013-01-01

    To perform a literature review on the clinical and/or laboratory performance of the use of calcium hydroxide in deep cavities of primary teeth. Literature in professional journals and summaries of BBO, LILACS, and MEDLINE databases (2000 to 2010) linked to the Virtual Health Library and PUBMED were searched. The search strategies used included the following descriptors: "dental caries" and "dental cavity lining" and "primary tooth", "dental cavity lining" and "primary tooth" and "calcium hydroxide", "dental caries" and "dental cavity lining" and "primary tooth" and "calcium hydroxide". The abstracts were selected according to the following inclusion criteria: published between 2000 and 2010, English language, trial and/or laboratory studies or literature review, regarding the use of calcium hydroxide in deep cavities of primary teeth. The abstracts analysis was performed by two reviewers separately. Potentially relevant studies available in full were analyzed based on criteria for quality assessment and displayed on an evidence-based table. After reading the abstracts (N = 39), six were selected as a basis for developing the study. Analysis suggests that calcium hydroxide is an interesting alternative in the control of caries lesions of primary teeth with the possibility of significantly increasing the success of indirect pulp capping; however, it should not be considered a determining factor in the success of a restorative procedure.

  13. The citotoxicity of calcium hydroxide intracanal dressing by MTT assay

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah

    2007-12-01

    Full Text Available Calcium hydroxide had been used as the intracanal dressing in endodontic treatment due to its high alkaline and high antimicrobial capacity. It also be able to dissolve the necrotic tissue, prevent the root resorbtion and regenerate a new hard tissue. The aim of this study is to identify the concentration of calcium hydroxide that has the lowest citotoxicity. There are 5 groups, each group had 8 samples with different concentration of calcium hydroxide. Group I: 50%, Group II: 55%, Group III: 60%, Group IV: 65% and Group V: 70%. The citotoxicity test by using enzymatic assay of MTT [3-(4.5- dimethylthiazol-2yl ]-2.5 diphenyl tetrazolium bromide, against fibroblast cell (BHK-21. The result of susceptibility test was showed by the citotoxicity detection of the survive cell of fibroblast that was measured spectrophotometrically using 595 nm beam. The data was analyzed using One-Way ANOVA test with significant difference α = 0.05 and subsequently LSD test. The result showed that in concentration 50%, 55%, 60%, 65%, and 70% calcium hydroxide had low toxicity, but calcium hydroxide 60%, had the lowest toxicity.

  14. Photo-oxidation of EPDM/layered double hydroxides composites: Influence of layered hydroxides and stabilizers

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The photo-oxidation of ethylene propylene diene monomer (EPDM/ layered double hydroxide (LDH composites as well as EPDM/LDH with stabilizers is studied under accelerated UV irradiation (λ≥290 nm at 60°C for different time intervals. The development of functional groups during oxidation was monitored by FT-IR spectroscopy. The photodegradation of the pristine polymer and composites take place and the increase in hydroxyl and carbonyl groups with irradiation times, was estimated. EPDM filled LDH showed higher degradation rate than pristine EPDM, while in acidic medium EPDM/LDH showed almost equal degradation as in isolated conditions. These results show the advantages of LDHs as a filler as well as an acid killer. The effect of stabilizers is very less because of their concentration in comparison of LDH.

  15. The effect of a combination antacid preparation containing aluminium hydroxide and magnesium hydroxide on rosuvastatin pharmacokinetics.

    Science.gov (United States)

    Martin, Paul D; Schneck, Dennis W; Dane, Aaron L; Warwick, Michael J

    2008-04-01

    Rosuvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor used for the treatment of dyslipidaemia, may be co-administered with antacids in clinical practice. This trial assessed the effect of simultaneous and separated administration of an antacid preparation containing aluminium hydroxide 220 mg/5 mL and magnesium hydroxide 195 mg/5 mL (co-magaldrox 195/220) on the pharmacokinetics of rosuvastatin. A randomised, open-label, three-way crossover trial was performed. Healthy male volunteers (n = 14) received a single dose of rosuvastatin 40 mg alone, rosuvastatin 40 mg plus 20 mL antacid suspension taken simultaneously, and rosuvastatin 40 mg plus 20 mL antacid suspension taken 2 h after rosuvastatin on three separate occasions with a washout of > or = 7 days between each. The primary parameters were area under the rosuvastatin plasma concentration-time curve from time zero to the last quantifiable concentration (AUC(0-t)) and maximum observed rosuvastatin plasma concentration (C(max)) in the absence and presence of antacid. When rosuvastatin and antacid were given simultaneously, the antacid reduced the rosuvastatin AUC(0-t) by 54% (90% confidence interval [CI] for the treatment 0.40-0.53) and C(max) by 50% (90% CI 0.41-0.60). When the antacid was given 2 h after rosuvastatin, the antacid reduced the rosuvastatin AUC(0-t) by 22% (90% CI 0.68-0.90) and the C(max) by 16% (90% CI 0.70-1.01). The effect of repeated antacid administration was not studied and it cannot be discounted that this may have resulted in a stronger interaction than that observed here. Simultaneous dosing with rosuvastatin and antacid resulted in a decrease in rosuvastatin systemic exposure of approximately 50%. This effect was mitigated when antacid was administered 2 h after rosuvastatin.

  16. Magnesium hydroxide nanoparticles synthesized in water-in-oil microemulsions.

    Science.gov (United States)

    Wu, Jianming; Yan, Hong; Zhang, Xuehu; Wei, Liqiao; Liu, Xuguang; Xu, Bingshe

    2008-08-01

    Well-dispersed magnesium hydroxide nanoplatelets were synthesized by a simple water-in-oil (w/o) microemulsion process, blowing gaseous ammonia (NH(3)) into microemulsion zones solubilized by magnesium chloride solution (MgCl(2)). Typical quaternary microemulsions of Triton X-100/cyclohexane/n-hexanol/water were used as space-confining microreactors for the nucleation, growth, and crystallization of magnesium hydroxide nanoparticles. The obtained magnesium hydroxide was characterized by field-emission scanning electron microscopy (FESEM), high-resolution transmission election microscopy (HRTEM), X-ray powder diffraction (XRD), laser light scattering, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis-differential scanning calorimetry (TGA-DSC). The mole ratio of water to surfactant (omega(0)) played an important role in the sizes of micelles and nanoparticles, increasing with the increase of omega(0). The compatibility and dispersibility of nanoparticles obtained from reverse micelles were improved in the organic phase.

  17. 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.

  18. Fluorometric determination of proteins using the terbium (III)-2-thenoyltrifluoroacetone-sodium dodecyl benzene sulfonate-protein system

    Energy Technology Data Exchange (ETDEWEB)

    Jia Zhen [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Department of Chemistry, Dezhou University, Dezhou 253023 (China); Yang Jinghe [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)]. E-mail: yjh@sdu.edu.cn; Wu Xia [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang Fei [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Guo Changying [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Liu Shufang [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2006-12-15

    It is found that in hexamethylene tetramine (HMTA)-HCl buffer of pH=8.00, proteins can enhance the fluorescence of terbium (III) (Tb{sup 3+})-2-thenoyltrifluoroacetone (TTA)-sodium dodecyl benzene sulfonate (SDBS) system. Based on this, a sensitive method for the determination of proteins is proposed. The experiments indicate that under the optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of proteins in the range of 4.0x10{sup -9}-7.5x10{sup -6}g/mL for bovine serum albumin (BSA), 5.0x10{sup -9}-1.5x10{sup -5}g/mL for human serum albumin (HSA), 1.0x10{sup -8}-7.5x10{sup -6}g/mL for egg albumin (EA). Their detection limits (S/N=3) are 0.5, 0.8 and 2.0ng/mL, respectively. The interaction mechanism is also studied.

  19. Terbium to Quantum Dot FRET Bioconjugates for Clinical Diagnostics: Influence of Human Plasma on Optical and Assembly Properties

    Directory of Open Access Journals (Sweden)

    Niko Hildebrandt

    2011-10-01

    Full Text Available Förster resonance energy transfer (FRET from luminescent terbium complexes (LTC as donors to semiconductor quantum dots (QDs as acceptors allows extraordinary large FRET efficiencies due to the long Förster distances afforded. Moreover, time-gated detection permits an efficient suppression of autofluorescent background leading to sub-picomolar detection limits even within multiplexed detection formats. These characteristics make FRET-systems with LTC and QDs excellent candidates for clinical diagnostics. So far, such proofs of principle for highly sensitive multiplexed biosensing have only been performed under optimized buffer conditions and interactions between real-life clinical media such as human serum or plasma and LTC-QD-FRET-systems have not yet been taken into account. Here we present an extensive spectroscopic analysis of absorption, excitation and emission spectra along with the luminescence decay times of both the single components as well as the assembled FRET-systems in TRIS-buffer, TRIS-buffer with 2% bovine serum albumin, and fresh human plasma. Moreover, we evaluated homogeneous LTC-QD FRET assays in QD conjugates assembled with either the well-known, specific biotin-streptavidin biological interaction or, alternatively, the metal-affinity coordination of histidine to zinc. In the case of conjugates assembled with biotin-streptavidin no significant interference with the optical and binding properties occurs whereas the histidine-zinc system appears to be affected by human plasma.

  20. Evidence of mass exchange between inside and outside of sonoluminescing bubble in aqueous solution of terbium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jinfu, E-mail: liang.shi2007@163.com [School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550001 (China); Chen, Weizhong, E-mail: wzchen@nju.edu.cn [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China); Wang, Xun; Yang, Jing; Chen, Zhan [The Key Laboratory of Modern Acoustics, Ministry of Education, Institution of Acoustics, Nanjing University, Nanjing 210093 (China)

    2016-12-16

    Highlights: • Time-resolved spectra of SBSL were obtained for Tb{sup 3+} ions emission lines. • Mass exchange between inside and outside of SL bubble was probed via Tb{sup 3+} ions lines. • The argon rectification hypothesis was tested by time-resolved spectra of SBSL. • The rate of mass exchange inside an SBSL bubble increases with increasing sound pressure. - Abstract: Spectra of single-bubble sonoluminescence (SBSL) were obtained for Tb{sup 3+} ions emission lines from bubbles in an aqueous solution of terbium chloride (TbCl{sub 3}). The spectra provide experimental evidence to prove that an air bubble driven by strong ultrasound will not eventually become a rectified pure argon bubble, which is not as predicted by the argon rectification hypothesis. The time-resolved spectra of SBSL show a mass exchange of material such as Tb{sup 3+} ions between the inside and outside of the bubble. With increasing sound pressure, the rate of mass exchange and the SBSL intensity increases.

  1. Optical properties and electrical transport of thin films of terbium(III bis(phthalocyanine on cobalt

    Directory of Open Access Journals (Sweden)

    Peter Robaschik

    2014-11-01

    Full Text Available The optical and electrical properties of terbium(III bis(phthalocyanine (TbPc2 films on cobalt substrates were studied using variable angle spectroscopic ellipsometry (VASE and current sensing atomic force microscopy (cs-AFM. Thin films of TbPc2 with a thickness between 18 nm and 87 nm were prepared by organic molecular beam deposition onto a cobalt layer grown by electron beam evaporation. The molecular orientation of the molecules on the metallic film was estimated from the analysis of the spectroscopic ellipsometry data. A detailed analysis of the AFM topography shows that the TbPc2 films consist of islands which increase in size with the thickness of the organic film. Furthermore, the cs-AFM technique allows local variations of the organic film topography to be correlated with electrical transport properties. Local current mapping as well as local I–V spectroscopy shows that despite the granular structure of the films, the electrical transport is uniform through the organic films on the microscale. The AFM-based electrical measurements allow the local charge carrier mobility of the TbPc2 thin films to be quantified with nanoscale resolution.

  2. 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.

  3. Micelle enhanced and terbium sensitized spectrofluorimetric determination of danofloxacin in milk using molecularly imprinted solid phase extraction

    Science.gov (United States)

    Kaur, Kuldeep; Saini, Shivender Singh; Malik, Ashok Kumar; Singh, Baldev

    2012-10-01

    An efficient molecularly imprinted solid phase extraction (MISPE)-spectrofluorimetric method was developed to sensitively determine danofloxacin (DAN) in milk samples. Solid phase extraction procedure using MISPE cartridges was first performed on milk samples and then spectrofluorimetric determination was done at 546 nm using an excitation wavelength of 285 nm in presence of terbium and sodium dodecyl benzene sulfonate (SDBS). It was found that SDBS significantly enhanced the fluorescence intensity of the DAN-Tb3+ complex. Various factors affecting the fluorescence intensity of DAN-Tb3+-SDBS system were studied and conditions were optimized. The enhanced fluorescence intensity of the system (ΔF) showed a good linear relationship with the concentration of DAN over the range of 8.4 × 10-9-3.4 × 10-7 mol L-1 with a correlation coefficient of 0.9996. The detection limit was determined as 2.0 × 10-9 mol L-1 and the limit of quantification was determined as 6.5 × 10-9 mol L-1. The MISPE-spectrofluorimetric procedure was successfully applied to the determination of DAN in milk samples. The method is simple, rapid, sensitive and allows interference free determination of DAN in complex fluorescent matrices like milk. The method can be used to determine whether the DAN residues in milk exceed MRLs or not.

  4. Study of quantum dot based on tin/yttrium mixed oxide doped with terbium to be used as biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Paganini, Paula P.; Felinto, Maria Claudia F.C.; Kodaira, Claudia A., E-mail: paulapaganini@usp.b, E-mail: mfelinto@ipen.b, E-mail: claudiakodaira@yahoo.co [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 (USP), SP (Brazil). Inst. de Quimica. Lab. de Elementos do Bloco f; Nunes, Luiz Antonio O., E-mail: luizant@ifsc.usp.b [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica. Dept. de Fisica e Informatica

    2009-07-01

    Quantum dots (semiconductors nanocrystals) have brought a promising field to develop a new generation of luminescent biomarkers. 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. These luminescent dots are functionalized with biomolecules. For the luminophore particle to be connect with biologicals molecules (for example covalent antibody) is necessary a previous chemical treatment to modify luminophore particle surface and this process is called functionalization. A prior chemical treatment with changes on the surface luminophore particle is necessary to couple the luminophore to biological molecules. This process can be used as coating which can protect these particles from being dissolved by acid as well as provide functional groups for biological conjugation. This work presents a photoluminescence study of nanoparticles based on tin/yttrium mixed oxides doped with terbium (SnO{sub 2}/Y{sub 2}O{sub 3}:Tb{sup 3+}), synthesized by coprecipitation method. The nanoparticles were submitted to thermal treatment and characterized by X-Ray Powder Diffraction (XRD) that showed cassiterite phase formation and the influence of thermal treatment on nanoparticles structures. These nanoparticles going to be functionalized with a natural polysaccharide (chitosan) in order to form microspheres. These microspheres going to be irradiated with gamma radiation to sterilization and it can be evaluated if the nanoparticles are resistant to irradiation and they do not lose functionality with this process. (author)

  5. DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    OGDEN DM; KIRCH NW

    2007-10-31

    This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.

  6. Charging and ion adsorption behaviour of different iron (hydr)oxides

    NARCIS (Netherlands)

    Venema, P.

    1997-01-01

    Metal (hydr)oxides are of importance for many soil systems. All metal (hydr)oxides have a surface charge that varies with the pH. The variation in this surface charge is caused by adsorption and desorption of protons. The adsorption of cat- and anions on the metal (hydr)oxide surface is

  7. Interaction of pristine hydrotalcite-like layered double hydroxides ...

    Indian Academy of Sciences (India)

    Metal oxides in general have surface acidic sites, but for exceptional circumstances, are not expected to mineralize CO2. Given their intrinsic basicity and an expandable interlayer gallery, the hydrotalcite-like layered double hydroxides (LDHs) are expected to be superior candidate materials for CO2 mineralization.

  8. The digestibility and intake of sodium hydroxide or local alkali ...

    African Journals Online (AJOL)

    The digestibility and intake of sodium hydroxide or local alkali-treated straw by goats. JA Ibeawuchi, AM Tula. Abstract. No Abstract. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Article Metrics. Metrics Loading ... Metrics powered by PLOS ALM.

  9. Interaction of pristine hydrotalcite-like layered double hydroxides ...

    Indian Academy of Sciences (India)

    Abstract. Metal oxides in general have surface acidic sites, but for exceptional circumstances, are not expected to mineralize CO2. Given their intrinsic basicity and an expandable interlayer gallery, the hydrotalcite-like layered double hydroxides (LDHs) are expected to be superior candidate materials for CO2 mineralization.

  10. Antimicrobial effectiveness of different preparations of calcium hydroxide

    Directory of Open Access Journals (Sweden)

    Anshul Gangwar

    2011-01-01

    Results and Conclusions: It was seen that calcium hydroxide and CMCP combination showed the maximum zone of inhibition, and maximum inhibitory effect was seen at 24 hours. The bacteria most susceptible was found to be S. aureus and the least susceptible was E. faecalis. Further clinical studies are required to substantiate these results.

  11. A comparison between sodium hydroxide treated and untreated bird ...

    African Journals Online (AJOL)

    A digestion and a growth trial was conducted, (i)to determine the effect of sodium hydroxide (NaOH)treatment of bird-proof sorghum (BPS) on nitrogen and energy digestibility, and (ii)to compare treated with untreated BPS as grain components in a pig growth diet. The polyphenol content of BPS was reduced from 1,33 to 0 ...

  12. Electronic spectra of anions intercalated in layered double hydroxides

    Indian Academy of Sciences (India)

    Transition metal complexes intercalated in layered double hydroxides have a different electronic structure as compared to their free state owing to their confinement within the interlayer gallery. UV–Vis absorptions of the intercalated complex anions show a significant shift as compared to their free state. The ligand to metal ...

  13. Oxidative leaching of chromium from layered double hydroxides ...

    Indian Academy of Sciences (India)

    The layered double hydroxide (LDH) of Zn with Cr on treatment with a hypochlorite solution releases chromate ions as a result of oxidative leaching by a dissolution–reprecipitation mechanism. The residue is found to be -Zn(OH)2. The LDH of Mg with Cr on the other hand is resistant to oxidative leaching. In contrast, a ...

  14. Page 1 Solubility of Rare Earth Hydroxides in Aqueous Sodium ...

    Indian Academy of Sciences (India)

    Solubility of Rare Earth Hydroxides in Aqueous Sodium Potassium Tartrate 317 undissolved after treatment with Rochelle Salt solution. The quantity measured was the weight of oxide in the filtrate. This was done by igniting the precipitated oxalate and also by titrating its sulphuric acid solution against standard potassium ...

  15. Praseodymium(III sulfate hydroxide, Pr(SO4(OH

    Directory of Open Access Journals (Sweden)

    Xiao-Juan Wang

    2011-02-01

    Full Text Available The title compound, Pr(SO4(OH, obtained under hydrothermal conditions, consists of PrIII ions coordinated by nine O atoms from six sulfate groups and three hydroxide anions. The bridging mode of the O atoms results in the formation of a three-dimensional framework, stabilized by two O—H...O hydrogen-bonding interactions.

  16. Line broadening in the PXRD patterns of layered hydroxides: The ...

    Indian Academy of Sciences (India)

    Unknown

    reflections and turbostratic disorder broadens the 0k´ reflections. The line broadening caused by struc- tural disorder has to be discounted before estimates of particle size are made by applying the Scherrer formula. Keywords. Layered double hydroxides; pyroaurite; structural disorder; stacking faults; turbostraticity;.

  17. Terbium-doped gadolinium oxysulfide (Gd2O2S:Tb) scintillation-based polymer optical fibre sensor for real time monitoring of radiation dose in oncology

    Science.gov (United States)

    Lewis, E.; O'Keeffe, S.; Grattan, M.; Hounsell, A.; McCarthy, D.; Woulfe, P.; Cronin, J.; Mihai, L.; Sporea, D.; Santhanam, A.; Agazaryan, N.

    2014-05-01

    A PMMA based plastic optical fibre sensor for use in real time radiotherapy dosimetry is presented. The optical fibre tip is coated with a scintillation material, terbium-doped gadolinium oxysulfide (Gd2O2S:Tb), which fluoresces when exposed to ionising radiation (X-Ray). The emitted visible light signal penetrates the sensor optical fibre and propagates along the transmitting fibre at the end of which it is remotely monitored using a fluorescence spectrometer. The results demonstrate good repeatability, with a maximum percentage error of 0.5% and the response is independent of dose rate.

  18. Compact all-fiber optical Faraday components using 65-wt%-terbium-doped fiber with a record Verdet constant of -32 rad/(Tm).

    Science.gov (United States)

    Sun, L; Jiang, S; Marciante, J R

    2010-06-07

    A compact all-fiber Faraday isolator and a Faraday mirror are demonstrated. At the core of each of these components is an all-fiber Faraday rotator made of a 4-cm-long, 65-wt%-terbium-doped silicate fiber. The effective Verdet constant of the terbium-doped fiber is measured to be -32 rad/(Tm), which is 27 x larger than that of silica fiber. This effective Verdet constant is the largest value measured to date in any fiber and is 83% of the Verdet constant of commercially available crystal used in bulk optics-based isolators. Combining the all-fiber Faraday rotator with fiber polarizers results in a fully fusion spliced all-fiber isolator whose isolation is measured to be 19 dB. Combining the all-fiber Faraday rotator with a fiber Bragg grating results in an all-fiber Faraday mirror that rotates the polarization state of the reflected light by 88 +/- 4 degrees .

  19. Picomolar Traces of Americium(III) Introduce Drastic Changes in the Structural Chemistry of Terbium(III): A Break in the "Gadolinium Break".

    Science.gov (United States)

    Welch, Jan M; Müller, Danny; Knoll, Christian; Wilkovitsch, Martin; Giester, Gerald; Ofner, Johannes; Lendl, Bernhard; Weinberger, Peter; Steinhauser, Georg

    2017-10-16

    The crystallization of terbium 5,5'-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H 2 O) 7 ZT] 2 ZT⋅10 H 2 O is isostructural to light lanthanide (Ce-Gd) 5,5'-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5'-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H 2 O) 8 ] 2 ZT 3 ⋅6 H 2 O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10 8 -fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microcopy. In addition, the inclusion properties of terbium 5,5'-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. A Case of Recurrent Renal Aluminum Hydroxide Stone

    Science.gov (United States)

    Cakıroglu, Basri; Dogan, Akif Nuri; Tas, Tuncay; Gozukucuk, Ramazan; Uyanik, Bekir Sami

    2014-01-01

    Renal stone disease is characterized by the differences depending on the age, gender, and the geographic location of the patients. Seventy-five percent of the renal stone components is the calcium (Ca). The most common type of the stones is the Ca oxalate stones, while Ca phosphate, uric acid, struvite, and sistine stones are more rarely reported. Other than these types, triamterene, adenosine, silica, indinavir, and ephedrine stones are also reported in the literature as case reports. However, to the best of our knowledge, aluminum hydroxide stones was not reported reported before. Herein we will report a 38-years-old woman with the history of recurrent renal colic disease whose renal stone was determined as aluminum hydroxide stone in type. Aluminum mineral may be considered in the formation of kidney stones as it is widely used in the field of healthcare and cosmetics. PMID:25013740

  1. Surface Properties of Metal Hydroxide Microparticles in the Ambient Air

    Directory of Open Access Journals (Sweden)

    Zakharenko Valery

    2017-01-01

    Full Text Available The adsorption and photoadsorption properties of Mg(OH2 and Ca(OH2 microparticles in the ambient air were investigated. The compositional analysis of an adsorption layer of microparticles was carried out. The kinetics of photodesorption of molecules from microcrystal surfaces and the interaction of HCFC-22 (CHF2Cl in the dark and under light were studied. Quantum yields and their spectral dependencies were determined for CO2 photodesorption, O2 and CO photoadsorption. The effect of weakly bound CO displacement from the surface of microparticles was revealed during dark adsorption of HCFC-22. It is supposed that adsorbed CO is formed as a result of atmospheric CO2 reduction after the break of Mg—OH bonds. In case of calcium hydroxide, CO is generated during the interaction of calcium hydroxide with carbon dioxide in the presence of water.

  2. Leaching kinetics of gibbsitic bauxite with sodium hydroxide

    Directory of Open Access Journals (Sweden)

    Abdel-Aal El-Sayed A.

    2016-01-01

    Full Text Available In this paper the results of a leaching kinetics study of bauxite ore with sodium hydroxide are presented. The effect of ore particle size, sodium hydroxide concentration and reaction temperature on the Al2O3 extraction rate was determined. The results obtained showed that 99% of Al2O3 was leached out using −200+270 mesh ore particle size at a reaction temperature of 105 °C for 60 min reaction time with 250 g/L NaOH. The solid-to-liquid ratio was maintained constant at 1:20. The results indicated that leaching of bauxite is the rate controlling process. The activation energy was determined to be 46.04 kJ/mole, which was characteristic for a chemically controlled process.

  3. CALCIUM HYDROXIDE IN ENDODONTIC TREATMENT OF PERIAPICALLY INFECTED TEETH

    Directory of Open Access Journals (Sweden)

    Rahmi Alma Farah Adang

    2006-04-01

    Full Text Available An inadequate endodontic treatment may affect the root canal system and spread beyond its apical foramina that elicit periodontal tissue developing into abscess, granuloma and radicular cyst. Periodical lesions can be treated with non surgical endodontic treatment using calcium hydroxide dressing. This case study is reporting teeth 11 with periodical lesions and infection. Evidence of a clinical healing and radiographic assessments were followed by a non surgical endodontic therapy. Successful treatment outcome is related to the elimination of infection agents from the root canal. This can activate a stimulation zone to promote regeneration. Calcium hydroxide used as a root canal dressing may promote alkalinity at the adjacent tissue , create favourable environmental condition in which hard tissue formation can occur, interfere the bactericidal activity, increase mineralization, and induce healing.

  4. Immobilization of laccase on hybrid layered double hydroxide

    Directory of Open Access Journals (Sweden)

    David Isidoro Camacho Córdova

    2009-01-01

    Full Text Available Crystals of Mg/Al layered double hydroxide were synthesized by alkaline precipitation and treated in an aqueous solution of glutamic acid. The glutamate ions were not intercalated into the interlayer space, but were detected in the material by Fourier transform infrared spectroscopy, suggesting that only the external surfaces of crystals were modified with glutamate ions. The resulting hybrid material was tested as a support for immobilization of the enzyme laccase (Myceliophthora thermophila. The immobilized enzyme preparation was characterized by electronic paramagnetic resonance spectroscopy and by assays of catalytic activity. The activity of the immobilized laccase was 97% of the activity in the free enzyme. Layered double hydroxide is a suitable support for use in remediation of soil studies.

  5. Ultrasound-assisted synthesis of magnesium hydroxide nanoparticles from magnesium.

    Science.gov (United States)

    Baidukova, Olga; Skorb, Ekaterina V

    2016-07-01

    Acoustic cavitation in water provides special kinetic and thermodynamic conditions for chemical synthesis and nanostructuring of solids. Using cavitation phenomenon, we obtained magnesium hydroxide from pure magnesium. This approach allows magnesium hydroxide to be synthesized without the requirement of any additives and non-aqueous solvents. Variation of sonochemical parameters enabled a total transformation of the metal to nanosized brucite with distinct morphology. Special attention is given to the obtaining of platelet-shaped, nanometric and de-agglomerated powders. The products of the synthesis were characterized by transmission electron microscopy (TEM), electron diffraction (ED), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Copyright © 2016 Elsevier B.V. All rights reserved.

  6. A Case of Recurrent Renal Aluminum Hydroxide Stone

    Directory of Open Access Journals (Sweden)

    Basri Cakıroglu

    2014-01-01

    Full Text Available Renal stone disease is characterized by the differences depending on the age, gender, and the geographic location of the patients. Seventy-five percent of the renal stone components is the calcium (Ca. The most common type of the stones is the Ca oxalate stones, while Ca phosphate, uric acid, struvite, and sistine stones are more rarely reported. Other than these types, triamterene, adenosine, silica, indinavir, and ephedrine stones are also reported in the literature as case reports. However, to the best of our knowledge, aluminum hydroxide stones was not reported reported before. Herein we will report a 38-years-old woman with the history of recurrent renal colic disease whose renal stone was determined as aluminum hydroxide stone in type. Aluminum mineral may be considered in the formation of kidney stones as it is widely used in the field of healthcare and cosmetics.

  7. Nickel hydroxide positive electrode for alkaline rechargeable battery

    Energy Technology Data Exchange (ETDEWEB)

    Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

    2018-02-20

    Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

  8. Synthesis and Characterization of Magnesium Hydroxide Nanoparticles via Hydrothermal Method

    OpenAIRE

    Sierra-Fernandez, A.; Flores-Carrasco, Gregorio; Gómez-Villalba, Luz Stella; Milošević, Olivera; Fort, R.; Rabanal, Maria Eugenia

    2014-01-01

    The interest in the nanostructured magnesium hydroxide (Mg(OH)2) is rapidly growing due to the fact that its physical and chemical properties makes it appropriate for multiple applications. So far, it has been used in medicine, industry, or more recently, in the conservation of cultural heritage. The current research is based on the synthesis and the characterization of functional and nanocrystalline Mg(OH)2 with different particle sizes, morphologies and high purity. The synthesis was carrie...

  9. Recent progress in the synthesis of nanostructured magnesium hydroxide

    OpenAIRE

    Balducci, Giulia; Bravo Diaz, Laura; Gregory, Duncan H.

    2017-01-01

    This review highlights synthetic routes for producing nanostructured magnesium hydroxide and focuses on how these various preparative approaches can produce Mg(OH)2 nanoparticles with controlled size and morphology. Mg(OH)2 nanocrystals with rod-, needle-, hollow tube- or platelet-like morphology can be synthesised by the modification of chemical and physical experimental parameters such as the selection of magnesium precursor, solvent and temperature or by employing surface modifiers and tem...

  10. Surface modification of magnesium hydroxide using vinyltriethoxysilane by dry process

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Shengjie [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences, Xining 810008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Lijuan, E-mail: lilj@isl.ac.cn [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences, Xining 810008 (China); Xu, Defang; Zhu, Donghai; Liu, Zhiqi; Nie, Feng [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences, Xining 810008 (China)

    2016-09-30

    Highlights: • A modification mechanism for magnesium hydroxide using silane by dry process was proposed. • Si−O−Mg bonds were formed directly by the reaction between Si-OC{sub 2}H{sub 5} and hydroxyl groups of magnesium hydroxide. • Dispersibility and compatibility of modified magnesium hydroxide improved in organic phase. - Abstract: In order to improve the compatibility between magnesium hydroxide (MH) and polymer matrix, the surface of MH was modified using vinyltriethoxysilane (VTES) by dry process and the interfacial interaction between MH and VTES was also studied. Zeta potential measurements implied that the MH particles had better dispersion and less aggregation after modification. Sedimentation tests showed that the surface of MH was transformed from hydrophilic to hydrophobic, and the dispersibility and the compatibility of MH particles significantly improved in the organic phase. Scanning electronic microscopy (SEM), Transmission electron microscopy (TEM) and X-ray powder diffraction (XRD) analyses showed that a thin layer had formed on the surface of the modified MH, but did not alter the material’s crystalline phase. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectra (XPS) and Thermogravimetric analysis (TGA) showed that the VTES molecules bound strongly to the surface of MH after modification. Chemical bonds (Si−O−Mg) formed by the reaction between Si-OC{sub 2}H{sub 5} and hydroxyl group of MH, also there have physical adsorption effect in the interface simultaneously. A modification mechanism of VTES on the MH surface by dry process was proposed, which different from the modification mechanism by wet process.

  11. Structure and thermodynamics of Cr-Fe hydroxide solid solutions

    Science.gov (United States)

    Guo, X.; Daemen, L.; Liu, N.; Wu, D.; Boukhalfa, H.; Migdissov, A. A.; Sun, C.; Navrotsky, A.; Roback, R. C.; Reimus, P. W.; Xu, H.

    2016-12-01

    Cr(VI) in the form of CrO42- is a pollutant species in soils and groundwater that poses health and environmental issues. Natural remediation processes include reduction of Cr(VI) to Cr(III). Via electron exchange with naturally abundant Fe-bearing minerals, which leads to the formation of Cr(III)-Fe(III) hydroxides. Because these phases are largely X-ray amorphous, their structural characteristics have not been well determined. In this work, we synthesized five samples with different Fe/Cr ratios, and we used synchrotron X-rays to obtain high-resolution diffraction (XRD) and absorption spectroscopy (XAS) data to study both their long range and local structural characteristics. In addition, infrared spectroscopy was conducted to obtain OH bonding information. Our results indicate that the crystallinity of these samples decreases systematically with increasing Fe/Cr ratio and that the Fe-rich samples may contain oxyhydroxides. Thermogravimetry (TG) and differential scanning calorimetry (DSC) coupled with mass spectrometry (MS) data indicate that these oxyhydrides contain about 15 - 33 wt. % water/OH- and a water contents decrease with increasing Fe/Cr ratio. Finally, the enthalpies of formation of this solid solution are all endothermic, suggesting the instability of these hydroxides relative to their corresponding oxides. These comprehensive structural and thermodynamic analyses yield fundamental parameters for understanding the behavior of Cr-Fe hydroxides/oxyhydroxides in the environment.

  12. Cuprous hydroxide in a solid form: does it exist?

    Science.gov (United States)

    Soroka, Inna L; Shchukarev, Andrey; Jonsson, Mats; Tarakina, Nadezda V; Korzhavyi, Pavel A

    2013-07-14

    Experimental studies have been performed to obtain the unknown cuprous hydroxide compound, which has recently been predicted theoretically (P. A. Korzhavyi et. al., Proc. Natl. Acad. Sci. U. S. A., 2012, 109, 686-689) to be metastable in a solid form. The reduction of Cu(2+) with ferrous ethylenediamine tetraacetate (EDTA) results in the formation of a yellow powder precipitate whose composition corresponds to CuOH × H2O as probed by Fourier Transform Infrared Spectroscopy (FTIR) and cryogenic X-ray Photoelectron Spectroscopy (XPS). A similar compound has been found on the surface of Cu-CuH powder stored in water, as detected by XPS. The reduction of Cu(2+) to Cu(+) with free radicals in aqueous solutions results in a Cu2O precipitate as the final product, while the formation of the yellow cuprous hydroxide colloids may be an intermediate step. Our studies reveal that cuprous hydroxide does exist in a solid form and most likely has a hydrated form, CuOH × H2O.

  13. CCDC 1410820: Experimental Crystal Structure Determination : heptakis(dimethylammonium) heptacosa-terbium dodecakis((1,1'-biphenyl)-3,4',5-tricarboxylate) hexakis(2-fluorobenzoate) hexakis(formate) hexatriacontakis(hydroxide) bis(oxide) unknown solvate hydrate

    KAUST Repository

    Alezi, Dalal

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

    Science.gov (United States)

    Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

    2017-11-01

    Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH)2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH)2-glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl2) at room temperature, but that in Ca(OH)2-water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH)2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Mechanistic study of inhibition of levofloxacin absorption by aluminum hydroxide.

    Science.gov (United States)

    Tanaka, M; Kurata, T; Fujisawa, C; Ohshima, Y; Aoki, H; Okazaki, O; Hakusui, H

    1993-01-01

    The mechanisms of reduction in absorption of levofloxacin (LVFX) by coadministration of aluminum hydroxide were studied. The partition coefficient of LVFX (0.1 mM) between chloroform and phosphate buffer (pH 5.0) was reduced by 60 to 70% with the addition of metal ions such as Cu2+, Al3+, and Fe2+ (0.8 mM), which indicated the formation of LVFX-metal ion chelates. However, there was no significant difference in absorption from rat intestine between the synthetic LVFX-Al3+ (1:1) chelate (6.75 mM) and LVFX (6.75 mM) in an in situ recirculation experiment. On the other hand, Al(NO3)3 (1.5 mM) significantly inhibited the absorption of LVFX (1.5 mM) by 20% of the control in the in situ ligated loop experiment, in which partial precipitation of aluminum hydroxide was observed in the dosing solution. Data for adsorption of LVFX and ofloxacin (OFLX) from aqueous solution by aluminum hydroxide were shown to fit Langmuir plots, and the adsorptive capacities (rmax) and the K values were 7.0 mg/g and 1.77 x 10(4) M-1 for LVFX and 7.4 mg/g and 1.42 x 10(4) M-1 for OFLX, respectively. The rate of adsorption of several quinolones (50 microM) onto aluminum hydroxide (2.5 mg/ml) followed the order norfloxacin (NFLX) (72.0%) > enoxacin (ENX) (61.0%) > OFLX (47.2%) approximately LVFX (48.1%). The elution rate of adsorbed quinolones with water followed the rank order LVFX (17.9%) approximately OFLX (20.9%) approximately ENX (18.3%) > NFLX (11.9%). These results strongly suggest that adsorption of quinolones by aluminum hydroxide reprecipitated in the small intestine would play an important role in the reduced bioavailability of quinolones after coadministration with aluminum-containing antacids. Images PMID:8257141

  16. Effect of Polyvinyl alcohol on Burning Rate for Flexible PVC with Addition of Magnesium hydroxide and Aluminum tri-hydroxide

    OpenAIRE

    Zuhair Jabbar Abdul Ameer; Diyar Hussein Habbeb

    2017-01-01

    In this research study the effect each of Polyvinyl alcohol, magnesium hydroxide, Aluminum trihydroxide on Polyvinyl chloride combustion speed used in the manufacture of electrical cables. Several composite samples were manufactured using the twin screw extruder. Combustion speed measured by the specification (ASTM D 635-03) as been studying composite samples surfaces using scanning electron microscope technology. The results that the parent used three additives reduce the combustion speed an...

  17. Effect of Polyvinyl alcohol on Burning Rate for Flexible PVC with Addition of Magnesium hydroxide and Aluminum tri-hydroxide

    Directory of Open Access Journals (Sweden)

    Zuhair Jabbar Abdul Ameer

    2017-05-01

    Full Text Available In this research study the effect each of Polyvinyl alcohol, magnesium hydroxide, Aluminum trihydroxide on Polyvinyl chloride combustion speed used in the manufacture of electrical cables. Several composite samples were manufactured using the twin screw extruder. Combustion speed measured by the specification (ASTM D 635-03 as been studying composite samples surfaces using scanning electron microscope technology. The results that the parent used three additives reduce the combustion speed and turning the surface of fine to coarse

  18. Advances in aluminum hydroxide-based adjuvant research and its mechanism

    Science.gov (United States)

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

  19. Advances in aluminum hydroxide-based adjuvant research and its mechanism

    OpenAIRE

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully und...

  20. Efficacy of three methods for inserting calcium hydroxide-based paste in root canals

    OpenAIRE

    Galvão, Thales; Camargo, Bernardo; Armada, Luciana; Alves, Flávio

    2017-01-01

    Background To compare the quality of calcium hydroxide paste fillings performed by three different techniques. Material and Methods Sixty extracted maxillary central incisors, with previous root canal treatment, were decoronated and the gutta-percha was completely removed from the root canals. Subsequently, the canals were filled with a calcium hydroxide-based paste composed of calcium hydroxide, bismuth carbonate, and glycerin. The study samples were divided into the following three groups o...

  1. Parametric Effect of Sodium Hydroxide and Sodium Carbonate on the Potency of a Degreaser

    OpenAIRE

    Babatope Abimbola Olufemi

    2016-01-01

    Experimental and statistical analysis was carried out on the comparative effect of sodium hydroxide and sodium carbonate on the potency of a laboratory produced degreaser in this work. The materials used include; octadecyl benzene sulphonic acid, sodium hydroxide, sodium carbonate, sodium metasilicate, carboxyl methyl cellulose (C.M.C), formadelhyde, perfume, colourant and distilled water. Different samples of degreaser were produced with varying composition of sodium hydroxide and sodium car...

  2. Advances in aluminum hydroxide-based adjuvant research and its mechanism.

    Science.gov (United States)

    He, Peng; Zou, Yening; Hu, Zhongyu

    2015-01-01

    In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants.

  3. The effect of magnesium hydroxide on the oral absorption of ibuprofen, ketoprofen and diclofenac.

    OpenAIRE

    Neuvonen, P J

    1991-01-01

    1. The effect of magnesium hydroxide on the oral absorption of ibuprofen, ketoprofen and diclofenac was investigated in two randomized cross-over studies, both consisting of two phases. 2. Single doses of magnesium hydroxide (850 mg) or of water (150 ml) only were given to six healthy volunteers immediately after the ingestion of ibuprofen (400 mg, Study 1), ketoprofen (50 mg, Study 2) or diclofenac (50 mg, Study 2). Plasma drug concentrations were measured up to 24 h. 3. Magnesium hydroxide ...

  4. Crystal structures of two mononuclear complexes of terbium(III) nitrate with the tripodal alcohol 1,1,1-tris-(hy-droxy-meth-yl)propane.

    Science.gov (United States)

    Gregório, Thaiane; Giese, Siddhartha O K; Nunes, Giovana G; Soares, Jaísa F; Hughes, David L

    2017-02-01

    Two new mononuclear cationic complexes in which the TbIII ion is bis-chelated by the tripodal alcohol 1,1,1-tris-(hy-droxy-meth-yl)propane (H3LEt, C6H14O3) were prepared from Tb(NO3)3·5H2O and had their crystal and mol-ecular structures solved by single-crystal X-ray diffraction analysis after data collection at 100 K. Both products were isolated in reasonable yields from the same reaction mixture by using different crystallization conditions. The higher-symmetry complex dinitratobis[1,1,1-tris-(hy-droxy-meth-yl)propane]-terbium(III) nitrate di-meth-oxy-ethane hemisolvate, [Tb(NO3)2(H3LEt)2]NO3·0.5C4H10O2, 1, in which the lanthanide ion is 10-coordinate and adopts an s-bicapped square-anti-prismatic coordination geometry, contains two bidentate nitrate ions bound to the metal atom; another nitrate ion functions as a counter-ion and a half-mol-ecule of di-meth-oxy-ethane (completed by a crystallographic twofold rotation axis) is also present. In product aqua-nitratobis[1,1,1-tris-(hy-droxy-meth-yl)propane]-terbium(III) dinitrate, [Tb(NO3)(H3LEt)2(H2O)](NO3)2, 2, one bidentate nitrate ion and one water mol-ecule are bound to the nine-coordinate terbium(III) centre, while two free nitrate ions contribute to charge balance outside the tricapped trigonal-prismatic coordination polyhedron. No free water mol-ecule was found in either of the crystal structures and, only in the case of 1, di-meth-oxy-ethane acts as a crystallizing solvent. In both mol-ecular structures, the two tripodal ligands are bent to one side of the coordination sphere, leaving room for the anionic and water ligands. In complex 2, the methyl group of one of the H3LEt ligands is disordered over two alternative orientations. Strong hydrogen bonds, both intra- and inter-molecular, are found in the crystal structures due to the number of different donor and acceptor groups present.

  5. Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

    National Research Council Canada - National Science Library

    Yingchun Zhang; Xiandong Liu; Chi Zhang; Mengjia He; Xiancai Lu

    2017-01-01

    In this study, by using first principles simulation techniques, we explored the basal spacings, interlayer structures, and dynamics of arsenite and arsenate intercalated Layered double hydroxides (LDHs...

  6. Effects of salinity and humic acid on the sorption of Hg on Fe and Mn hydroxides.

    Science.gov (United States)

    Liang, Peng; Li, Yi-Chun; Zhang, Chan; Wu, Sheng-Chun; Cui, Hao-Jie; Yu, Shen; Wong, Ming H

    2013-01-15

    The objective of this study was to investigate the influence of humic acid (HA) and salinity on adsorption of Hg on the amorphous and crystalline of iron and manganese hydroxides. The results show that the adsorption of Hg(2+) on Fe and Mn hydroxides was inhibited in marine system due to the formation of stable, nonsorbing aqueous HgCl(2) complexes in solution. Moreover, Cl(-) inhibited the Hg(2+) adsorption more severely on amorphous than crystalline hydroxides. The addition of HA inhibited Hg(2+) adsorption on Fe and Mn hydroxides in freshwater system might be attributed to the competition between Hg(2+) and HA on adsorption to Fe and Mn hydroxides. In contrast, the addition of HA promoted Hg(2+) adsorption on Fe and Mn hydroxides in the marine system, which might be due to the addition of humic acid resulted in the reaction between Cl(-) and HA, and therefore the reducing of Cl(-) promoted more Hg(2+) on Fe and Mn hydroxides. In addition, the influence of HA on Hg(2+) adsorption on Fe and Mn hydroxides are more visible for crystalline than amorphous hydroxides. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Endodontic Release System for Apexification with Calcium Hydroxide Microspheres

    Science.gov (United States)

    Strom, T.A.; Arora, A.; Osborn, B.; Karim, N.; Komabayashi, T.; Liu, X.

    2012-01-01

    The use of calcium hydroxide (CH) as an intracanal medicament for apexification is widespread. However, because of a short residence time in the root canal, the CH must be refreshed frequently, increasing the number of appointments required and leading to patient non-compliance. We hypothesized that a core-/shell-structured CH microsphere system would lead to sustained slow release of calcium and hydroxide ions of CH for long periods of time, eliminating the need for multiple visits for apexification. In this study, calcium hydroxide microspheres (CHMSs) with a core/shell structure were prepared by an emulsion method. The CHMS shell was composed of alginate, which was crosslinked by the Ca2+ released from the CH in the CHMSs. Therefore, this system provides a unique feedback loop that controls the release of ions from the CHMSs. The in vitro experiments from the root canals of extracted human teeth showed that the CHMSs had a sustained, slow release of Ca2+, at a constant rate of approximately 2 to 3% per month from day one to the six-month endpoint of the experiment. After 6 months, 72.1 ± 5.8% of the total CH from the CHMSs remained in the root canals of the teeth, while only 46.9 ± 10.9% and 36.8 ± 7.5% remained from a commercial product (UltraCal®XS) and CH powder alone, respectively (p formulations (CHMS, UltraCal® XS, and CH powder) in the extracted teeth never rose above 9 during the release period, indicating a buffering effect of the teeth. The core-/shell-structured CHMSs are, therefore, a promising delivery vehicle for the sustained slow release of Ca2+ and OH- in the root canal. PMID:22914537

  8. Catalytic oxidation of sulfide ions over nickel hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A.; Khristov, P. [Institute of Catalysis, Bulgarian Academy of Sciences, Sofia (Bulgaria); Losev, A. [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria)

    1996-01-18

    The catalytic sulfide ion oxidation by oxygen to elemental sulfur over {beta}-Ni(OH){sub 2} and LiNiO{sub 2} has been studied. As a result of experimental investigation performed, a reaction mechanism is suggested which involves heterogeneous and homogeneous processes. Dioxygen activation in the heterogeneous process proceeds via a redox Ni{sup 2+} <-> Ni{sup 3+} transition and participation of OH{sup -} groups. The active HO{sup -}{sub 2} species thus formed carries on the reaction in homogeneous phase. Nickel hydroxides are promising catalysts for practical application

  9. Iron oxide hydroxide nanoflower assisted removal of arsenic from water

    Energy Technology Data Exchange (ETDEWEB)

    Raul, Prasanta Kumar, E-mail: prasanta.drdo@gmail.com [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India); Devi, Rashmi Rekha; Umlong, Iohborlang M. [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India); Thakur, Ashim Jyoti [Department of Chemical Sciences, Tezpur University, Napaam, Tezpur 784028, Assam (India); Banerjee, Saumen; Veer, Vijay [Defence Research Laboratory, Post Bag No. 2, Tezpur 784001, Assam (India)

    2014-01-01

    Graphical abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. TEM image clearly reveals that the nanoparticle looks flower like morphology with average particle size less than 20 nm. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature and the data fitted to different isotherm models indicate the heterogeneity of the adsorbent surface. The material can be regenerated up to 70% using dilute hydrochloric acid and it would be utilized for de-arsenification purposes. - Highlights: • The work includes synthesis of iron oxide hydroxide nanoflower and its applicability for the removal of arsenic from water. • The nanoparticle was characterized using modern instrumental methods like FESEM, TEM, BET, XRD, etc. • The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic at room temperature. • The sorption is multilayered on the heterogeneous surface of the nano adsorbent. • The mechanism of arsenic removal of IOH nanoflower follows both adsorption and ion-exchange. - Abstract: Non-magnetic polycrystalline iron oxide hydroxide nanoparticle with flower like morphology is found to play as an effective adsorbent media to remove As(III) from 300 μg L{sup −1} to less than 10 μg L{sup −1} from drinking water over wide range of pH. The nanoparticle was characterized by X-ray powder diffraction analysis (XRD), BET surface area, FTIR, FESEM and TEM images. TEM image clearly reveals flower like morphology with average particle size less than 20 nm. The nanoflower morphology is also supported by FESEM images. The maximum sorption capacity of the sorbent is found to be 475 μg g{sup −1} for arsenic and the data fitted to different isotherm models indicate the

  10. LAYERED DOUBLE HYDROXIDES: NANOMATERIALS FOR APPLICATIONS IN AGRICULTURE

    Directory of Open Access Journals (Sweden)

    Luíz Paulo Figueredo Benício

    2015-02-01

    Full Text Available The current research aims to introduce Layered Double Hydroxides (LDH as nanomaterials to be used in agriculture, with particular reference to its use as storage and slow release matrix of nutrients and agrochemicals for plant growing. Structural characteristics, main properties, synthesis methods and characterization of LDH were covered in this study. Moreover, some literature data have been reported to demonstrate their potential for storage and slow release of nitrate, phosphate, agrochemicals, besides as being used as adsorbent for the wastewater treatment. This research aims to expand, in near future, the investigation field on these materials, with application in agriculture, increasing the interface between chemistry and agronomy.

  11. Bonding by Hydroxide-Catalyzed Hydration and Dehydration

    Science.gov (United States)

    Gwo, Dz-Hung

    2008-01-01

    A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to

  12. The response behavior of PPy-DB18C6 electrode to terbium(III in acetonitrile and its thermodynamic application

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Arbab Zavar

    2016-11-01

    Full Text Available Polypyrrole modified electrode prepared by electropolymerization of pyrrole in the presence of a complexing ligand, dibenzo-18-crown-6(DB18C6, was prepared and investigated as a Tb3+-selective electrode in acetonitrile. The potentiometric response of the electrode was linear within the Tb3+ concentration range 1 × 10−5–1 × 10−2 M with a Nernstian slope of 20.9 mVdecade−1 in AN. The electrode was applied to study the complexation of the terbium(III ion in acetonitrile with such other basic aprotic solvent molecules (D as dimethyl sulfoxide, N,N-dimethyl formamide, propylene carbonate and pyridine. The successive complex formation constant (βi and Gibbs energies of transfer (ΔGtr of Tb3+ in AN in relation to such D were obtained.

  13. Luminescence and Magnetic Properties of Two Three-Dimensional Terbium and Dysprosium MOFs Based on Azobenzene-4,4′-Dicarboxylic Linker

    Directory of Open Access Journals (Sweden)

    Belén Fernández

    2016-02-01

    Full Text Available We report the in situ formation of two novel metal-organic frameworks based on terbium and dysprosium ions using azobenzene-4,4′-dicarboxylic acid (H2abd as ligand, synthesized by soft hydrothermal routes. Both materials show isostructural three-dimensional networks with channels along a axis and display intense photoluminescence properties in the solid state at room temperature. Textural properties of the metal-organic frameworks (MOFs have been fully characterized although no appreciable porosity was obtained. Magnetic properties of these materials were studied, highlighting the dysprosium material displays slightly frequency-dependent out of phase signals when measured under zero external field and under an applied field of 1000 Oe.

  14. Interaction of Pu(IV,VI) hydroxides/oxides with metal hydroxides/oxides in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Fedoseev, A.M.; Krot, N.N.; Budantseva, N.A.; Bessonov, A.A.; Nikonov, M.V.; Grigoriev, M.S.; Garnov, A.Y.; Perminov, V.P.; Astafurova, L.N. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Physical Chemistry

    1998-08-01

    The primary goal of this investigation was to obtain data on the possibility, extent, and characteristics of interaction of Pu(IV) and (VI) with hydroxides and oxides of d-elements and other metals [Al(III), LA(III), and U(VI)] in alkaline media. Such information is important in fundamental understanding of plutonium disposition and behavior in Hanford Site radioactive tank waste sludge. These results supply essential data for determining criticality safety and in understanding transuranic waste behavior in storage, retrieval, and treatment of Hanford Site tank waste.

  15. Isothermal decomposition kinetics of nickel (II) hydroxide powder

    Energy Technology Data Exchange (ETDEWEB)

    Carney, C.S., E-mail: Casey.Carney@CONTR.NETL.DOE.GOV [National Energy Technology Laboratory, U.S. Dept. of Energy, Albany, OR (United States); AECOM, P.O. Box 1959, Albany, OR (United States); Chinn, R.E.; Doğan, Ö.N. [National Energy Technology Laboratory, U.S. Dept. of Energy, Albany, OR (United States); Gao, M.C. [National Energy Technology Laboratory, U.S. Dept. of Energy, Albany, OR (United States); AECOM, P.O. Box 1959, Albany, OR (United States)

    2015-09-25

    Highlights: • A first order random nucleation model was proposed for the decomposition of nickel hydroxide. • Trapped lattice product water greatly suppressed high conversion reaction rates. • Annealing experiments of the Ni–Ni(OH){sub 2}–NiO phase triangle yielded only two phases: Ni and NiO. • This Ni–Ni(OH){sub 2}–NiO phase triangle in the Ni-rich corner of the Ni–O–H system was confirmed. - Abstract: Nickel (II) hydroxide powder was investigated by thermogravimetry for isothermal decomposition kinetics and verification of the Ni–O–H ternary phase diagram at low temperatures. The activation energy and frequency factor were measured as E{sub a} = 134 kJ/mol and A = 1.27 × 10{sup 10} s{sup −1}, respectively. The validity of the first-order random nucleation model was confirmed, as opposed to diffusion and or moving-boundary models. The dependence of TGA results on specimen size was noted. The Ni–Ni(OH){sub 2}–NiO phase triangle was confirmed. Accordingly, a thermodynamic description of the system was established in the Ni-rich corner, and the isotherm at room temperature is calculated.

  16. Adsorption kinetic and thermodynamic studies of phosphate onto tantalum hydroxide.

    Science.gov (United States)

    Yu, Shi-Hua; Dong, Xiao-Le; Gong, Hong; Jiang, Heng; Liu, Zhi-Gang

    2012-12-01

    Tantalum hydroxide exhibits the ability for the removal of phosphate from aqueous solution. The kinetic study, adsorption isotherm, thermodynamic study, desorption, and foreign anions effect were examined in batch experiments. The kinetic process was very well described by a pseudo-second-order rate model. The adsorption isotherms showed that phosphate uptake fitted with a Langmuir-type model very well, with an increase of PO4(3-) adsorption capacity from 78.5 to 97.0 mg/g when the temperature increased from 298 to 338 K. The negative values of deltaG(0) and the positive values of deltaH(0) indicated that the phosphate adsorption process was spontaneous and endothermic naturally. While the deltaS(0) values obtained were positive, indicating an increase in randomness at the solid-liquid interface during the adsorption. Foreign anions tests showed that the presence of competitive ions cause minimal interference with the adsorption of phosphate on tantalum hydroxide.

  17. A novel photoluminescent nanohybrid of poly(ε-caprolactone) grafted Mg/Al layered double hydroxides and Tb{sup 3+} ions: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Bach, Long Giang [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Center for Advanced Materials Research, Nguyen Tat Thanh Unviersity, Ho Chi Minh City (Viet Nam); Islam, Md. Rafiqul [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Energy and Mineral Resources Division, Ministry of Power, Energy and Mineral Resources, Government of the People’s Republic of Bangladesh, Dhaka 1000 (Bangladesh); Cao, Xuan Thang [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Park, Jong Myung [Surface Engineering Laboratory, Graduate Institute of Ferrous Technology, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Lim, Kwon Taek, E-mail: ktlim@pknu.ac.kr [Department of Imaging System Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2014-01-05

    Highlights: • The photoluminescent LDHs-PCL-Tb{sup 3+} nanohybrid was successfully synthesized. • Structure and morphology of LDHs-g-PCL-Tb{sup 3+} were investigated by FT-IR, SEM, and TGA. • XPS and EDS analyses further suggested the formation of LDHs-g-PCL-Tb{sup 3+}. • Optical property of LDHs-g-PCL-Tb{sup 3+} was investigated by PL. -- Abstract: This paper demonstrates a systematic study of the synthesis and characterization of the hybrid of Mg–Al layer double hydroxides (LDHs), poly(ε-caprolactone) (PCL), and terbium ions (Tb{sup 3+}). The hybrid LDH-g-PCL-Tb{sup 3+}-1,10-phenanthroline (Phen) was prepared by the combination of ring opening polymerization (ROP), click chemistry, and coordination chemistry. First, LDHs with a molar ratio of Mg/Al = 2 were prepared by the co-precipitation method, which was subsequently functionalized with (3-chloropropyl) trimethoxysilane in order to introduce azide groups through the reaction of chlorine with sodium azide. Meanwhile, the acetylene functionalized PCL was prepared by ROP of ε-CL, followed by esterification of the hydroxyl groups using succinic anhydride. The click reaction of alkyne-PCL and N{sub 3}-LDHs successfully afforded LDH-g-PCL, which was coordinated with Tb{sup 3+} ions in the presence of Phen. The structure and properties of the nanohybrids were investigated by FT-IR, XPS, EDS, SEM, and TGA analyses. The data indicate the coordination of Tb{sup 3+} ions with LDH-g-PCL nanohybrids. The content of Tb{sup 3+} ions in the LDH-g-PCL-Tb{sup 3+}-Phen complex was calculated to be 8.7% (w/w). The LDH-g-PCL-Tb{sup 3+}-Phen complexes showed four emission bands with high fluorescence intensity centered at 489 nm ({sup 5}D{sub 4} → {sup 7}F{sub 6}), 546 nm ({sup 5}D{sub 4} → {sup 7}F{sub 5}), 586 nm ({sup 5}D{sub 4} → {sup 7}F{sub 4}) and 623 nm ({sup 5}D{sub 4} → {sup 7}F{sub 3}) with excitation at 328 nm ({sup 3}F{sub 6} → {sup 5}G{sub 6}). The stability of LDH-g-PCL-Tb{sup 3+}-Phen complexes

  18. Structural perturbation of diphtheria toxoid upon adsorption to aluminium hydroxide adjuvant

    NARCIS (Netherlands)

    Regnier, Marie; Metz, Bernard; Tilstra, Wichard; Hendriksen, Coenraad; Jiskoot, Wim; Norde, Willem; Kersten, Gideon

    2012-01-01

    Aluminium-containing adjuvants are often used to enhance the potency of vaccines. In the present work we studied whether adsorption of diphtheria toxoid to colloidal aluminium hydroxide induces conformational changes of the antigen. Diphtheria toxoid has a high affinity for the aluminium hydroxide

  19. Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin.

    Science.gov (United States)

    Montero, Janaina Corazza; Mori, Graziela Garrido

    2012-01-01

    This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin.

  20. Assessment of ion diffusion from a calcium hydroxide-propolis paste through dentin

    Directory of Open Access Journals (Sweden)

    Janaina Corazza Montero

    2012-08-01

    Full Text Available This study evaluated the ability of ions from a non-alcoholic calcium hydroxide-propolis paste to diffuse through dentinal tubules. Thirty-six single-rooted bovine teeth were used. The tooth crowns were removed, and the root canals were instrumented and divided into 3 groups: Group 1 - calcium hydroxide-propylene glycol paste; Group 2 - calcium hydroxide-saline solution paste; Group 3 - calcium hydroxide-propolis paste. After the root canal dressings were applied, the teeth were sealed and placed in containers with deionized water. The pH of the water was measured after 3, 24, 72 and 168 hours to determine the diffusion of calcium hydroxide ions through the dentinal tubules. All of the pastes studied promoted the diffusion of calcium hydroxide ions through the dentinal tubules. Associating propolis to calcium hydroxide resulted in a pH increase, which occurred with greater intensity after 72 hours. The calcium hydroxide-propolis paste was able to diffuse in dentin.

  1. Luminescent europium and terbium complexes of dipyridoquinoxaline and dipyridophenazine ligands as photosensitizing antennae: structures and biological perspectives.

    Science.gov (United States)

    Dasari, Srikanth; Patra, Ashis K

    2015-12-14

    The europium(III) and terbium(III) complexes, namely [Eu(dpq)(DMF)2(NO3)3] (1), [Eu(dppz)2(NO3)3] (2), [Tb(dpq)(DMF)2Cl3] (3), and [Tb(dppz)(DMF)2Cl3] (4), where dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 1 and 3), dipyrido[3,2-a:2',3'-c]phenazine (dppz in 2 and 4) and N,N'-dimethylformamide (DMF) have been isolated, characterized from their physicochemical data, luminescence studies and their interaction with DNA, serum albumin protein and photo-induced DNA cleavage activity are studied. The X-ray crystal structures of complexes 1-4 show discrete mononuclear Ln(3+)-based structures. The Eu(3+) in [Eu(dpq)(DMF)2(NO3)3] (1) and [Eu(dppz)2(NO3)3] (2) as [Eu(dppz)2(NO3)3]·dppz (2a) adopts a ten-coordinated bicapped dodecahedron structure with a bidentate N,N-donor dpq ligand, two DMF and three NO3(-) anions in 1 and two bidentate N,N-donor dppz ligands and three NO3(-) anions in 2. Complexes 3 and 4 show a seven-coordinated mono-capped octahedron structure where Tb(3+) contains bidentate dpq/dppz ligands, two DMF and three Cl(-) anions. The complexes are highly luminescent in nature indicating efficient photo-excited energy transfer from the dpq/dppz antenna to Ln(3+) to generate long-lived emissive excited states for characteristic f → f transitions. The time-resolved luminescence spectra of complexes 1-4 show typical narrow emission bands attributed to the (5)D0 → (7)F(J) and (5)D4 → (7)F(J) f-f transitions of Eu(3+) and Tb(3+) ions respectively. The number of inner-sphere water molecules (q) was determined from luminescence lifetime measurements in H2O and D2O confirming ligand-exchange reactions with water in solution. The complexes display significant binding propensity to the CT-DNA giving binding constant values in the range of 1.0 × 10(4)-6.1 × 10(4) M(-1) in the order 2, 4 (dppz) > 1, 3 (dpq). DNA binding data suggest DNA groove binding with the partial intercalation nature of the complexes. All the complexes also show binding propensity (K(BSA)

  2. Mg/Al double-metal hydroxide regeneration of anion exchange resin by electric field intensification.

    Science.gov (United States)

    Wang, Ying; Li, Zhun; Li, Yansheng; Liu, Zhigang

    2017-03-01

    Fouled anion exchange resins were regenerated by electric field intensification of Mg/Al double-metal hydroxides. Regenerative experiments were performed with varying voltages (10-30 V) and dosages of Mg/Al hydroxides (0.045-0.135 mol and 0.015-0.045 mol, respectively) for 1-5 h. Optimal results were obtained under the following regenerative conditions: 20 V, 4 h, and 0.09/0.03 mol of Mg/Al hydroxides. The maximum regenerative capacity of resins was increased to 41.07%. The regenerative mechanism was presented by Fourier-transform infrared spectrum of resins and Mg/Al hydroxides, and the regenerative degree was analyzed with respect to conductivity, pH value, and electric current. Mg/Al hydroxides were also recycled after the regeneration. This method was proven to be cost-effective and environmentally friendly.

  3. Dynamic monitoring of structural changes in nickel hydroxide electrodes during discharge in batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M.; Becker, D.; Garaventta, G.; Visintin, A.; Castro, E.B. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 16, Suc. 4, 1900 La Plata (Argentina); Real, S.G., E-mail: sreal@inifta.unlp.edu.ar [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 16, Suc. 4, 1900 La Plata (Argentina)

    2011-09-30

    The nickel hydroxide electrode is used as the positive plate of many rechargeable battery systems such as the nickel/cadmium, nickel/hydrogen, and nickel/metal hydrides. The electrochemical energy storage in the nickel hydroxide electrodes is related to the reversible characteristics of the redox couple nickel hydroxide/ox hydroxide. In the present work we describe the use of the electrochemical impedance spectroscopy (EIS) technique as a tool to characterize the dynamic behaviour of nickel hydroxide electrodes at different states of discharge (SOD) in KOH 7 M electrolytic solutions. The parameter identification procedure allows the estimation of the active area per unit volume, the solution conductivity as well as diffusion and kinetic constants related to the process, that represent very important parameters to evaluate the electrode performance.

  4. Synthesis and anion-exchange reactions of a new anionic clay, α-magnesium hydroxide.

    Science.gov (United States)

    Nethravathi, C; Rajamathi, Jacqueline T; George, Preeta; Rajamathi, Michael

    2011-02-15

    A new anionic clay, α-magnesium hydroxide, was synthesized by hydrolysis of magnesium acetate in propylene glycol. The structure of this α-hydroxide is similar to that of hydrotalcites. It consists of positively charged magnesium hydroxide layers arising out of partial protonation of the hydroxyl groups of the [Mg(OH)(2)] layers and loosely held anions in the interlayer region. As expected it ages readily in water to give β-magnesium hydroxide, brucite. While anion-exchange reactions of α-magnesium hydroxide could not be carried out in aqueous medium a number of anion-exchange reactions could be carried out successfully in ethanol medium. Copyright © 2010 Elsevier Inc. All rights reserved.

  5. Mechanochemical changes in mixture of magnesium and aluminium hydroxides

    Directory of Open Access Journals (Sweden)

    Luxová Mária

    2000-09-01

    Full Text Available Complex oxides with the spinel structure often called “spinels” belong to the group of strategic materials which are used in the wide area of modern technologies. They exhibit excellent magnetic, refractory, semiconducting, catalytic and sorption properties. Spinels based on magnesium aluminate (MA spinels are used for the preparation of refractory ceramic materials and bricks. Due to its good properties MA spinel is predestinated for special applications in electronics.Several methods and precursors for the synthesis of MA spinel have been studied experimentally. The conventional process of MA spinel preparation based on the high temperature solid state reaction of precursors is connected with the difficulty to obtain the high spinel phase purity required for its special applications. From the viewpoint of final material properties and of intensification of solid state reactions, the non-standard mechanochemical techniques are suitable.In the paper, results of the mechanochemical modification of the mixture of crystalline hydroxide precursors caused by the high-energy milling and subsequent heating in the temperature range 300-1500 °C are presented.Mixtures of brucite and gibbsite in the molar ratio 1:2 were submitted to grinding in a planetary mill using the corundum chamber for various milling times (0.5-12 hours. The specific surface area of the milled samples was determined by the BET method. Changes in the structure of mechanosynthesized products and the evolution of the spinel phase during the subsequent calcination of both mechanosynthesized samples and reference homogenised mixtures were monitored by the X-ray diffraction analysis and IR spectroscopy. The degree of conversion of hydroxide mixture to the MA spinel was determined by chelatometry.During the early stage of grinding (up to 1 hour, a considerable refinement of hydroxide mixture occurs. With the increasing grinding time, amorphisation of structure as well as a gradual

  6. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  7. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amides, from ammonium hydroxide... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... subject to reporting. (1) The chemical substance identified as amides, from ammonium hydroxide - maleic...

  8. Spin Waves in Terbium

    DEFF Research Database (Denmark)

    Jensen, J.; Houmann, Jens Christian Gylden

    1975-01-01

    The selection rules for the linear couplings between magnons and phonons propagating in the c direction of a simple basal-plane hcp ferromagnet are determined by general symmetry considerations. The acoustic-optical magnon-phonon interactions observed in the heavy-rare-earth metals have been expl...... by Liu. The coupled magnon—transverse-phonon system for the c direction of Tb is analyzed in detail, and the strengths of the couplings are deduced as a function of wave vector by combining the experimental studies with the theory....

  9. Spin Waves in Terbium

    DEFF Research Database (Denmark)

    Jensen, J.; Houmann, Jens Christian Gylden; Bjerrum Møller, Hans

    1975-01-01

    The energies of spin waves propagating in the c direction of Tb have been studied by inelastic neutron scattering, as a function of a magnetic field applied along the easy and hard directions in the basal plane, and as a function of temperature. From a general spin Hamiltonian, consistent...... with the symmetry, we deduce the dispersion relation for the spin waves in a basal-plane ferromagnet. This phenomenological spin-wave theory accounts for the observed behavior of the magnon energies in Tb. The two q⃗-dependent Bogoliubov components of the magnon energies are derived from the experimental results...

  10. Layered Double Hydroxide-Based Nanocarriers for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Xue Bi

    2014-06-01

    Full Text Available Biocompatible clay materials have attracted particular attention as the efficient drug delivery systems (DDS. In this article, we review developments in the use of layered double hydroxides (LDHs for controlled drug release and delivery. We show how advances in the ability to synthesize intercalated structures have a significant influence on the development of new applications of these materials. We also show how modification and/or functionalization can lead to new biotechnological and biomedical applications. This review highlights the most recent progresses in research on LDH-based controlled drug delivery systems, focusing mainly on: (i DDS with cardiovascular drugs as guests; (ii DDS with anti-inflammatory drugs as guests; and (iii DDS with anti-cancer drugs as guests. Finally, future prospects for LDH-based drug carriers are also discussed.

  11. Biological evaluation of layered double hydroxides as efficient drug vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Li Yan; Liu Dan; Chang Qing; Liu Dandan; Xia Ying; Liu Shuwen; Peng Nanfang; Yang Xu [Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Huazhong Normal University, Wuhan 430079 (China); Ai Hanhua [College of Physical Science and Technology, Huazhong Normal University, Wuhan 430079 (China); Xi Zhuge, E-mail: yangxu@mail.ccnu.edu.cn [Tianjin Institutes of Health and Environmental Medicine, Tianjin 300050 (China)

    2010-03-12

    Recently there has been a rapid expansion of the development of bioinorganic hybrid systems for safe drug delivery. Layered double hydroxides (LDH), a variety of available inorganic matrix, possess great promise for this purpose. In this study, an oxidative stress biomarker system, including measurement of reactive oxygen species, glutathione content, endogenous nitric oxide, carbonyl content in proteins, DNA strand breaks and DNA-protein crosslinks, was designed to evaluate the biocompatibility of different concentrations of nano-Zn/Al-LDH with a Hela cell line. The drug delivery activity of the LDH-folic-acid complex was also assessed. The resulting data clearly demonstrated that nano-LDH could be applied as a relatively safe drug vehicle with good delivery activity, but with the caveat that the effects of high dosages observed here should not be ignored when attempting to maximize therapeutic activity by increasing LDH concentration.

  12. Course and outcome of accidental sodium hydroxide ocular injury.

    Science.gov (United States)

    Sharma, Namrata; Singh, Digvijay; Sobti, Amit; Agarwal, Prakashchand; Velpandian, Thirumurthy; Titiyal, Jeewan S; Ghose, Supriyo

    2012-10-01

    To evaluate the course and outcome of patients with accidental ocular alkali burns. Prospective, interventional case series. Study of a cohort of 16 patients (31 eyes) who sustained concomitant accidental sodium hydroxide ocular burns and received appropriate treatment at a tertiary care eye hospital in India. The patients were followed up for 1 year, and parameters including best-corrected visual acuity, epithelial defect area, conjunctival and limbal involvement, and injury-related complications were evaluated. Severe sodium hydroxide exposure of a mean duration of 12 ± 2.5 minutes and delay in specialist eye care caused moderate to severe injury (grade II, 19% [n = 6]; grade III, 19% [n = 6]; grade IV, 10% [n = 3]; and grade VI, 52% [n = 16]). Median best-corrected visual acuity at presentation was 1.0 logarithm of the minimal angle of resolution (logMAR) units (range, 0.3 to 1.9 logMAR units), and at 1 year, it was 1.0 logMAR units (range, 0 to 1.9 logMAR units; P = .121). The median initial epithelial defect was 100 mm(2) (range, 18 to 121 mm(2)), which healed in all eyes by 3.5 months. Initial median limbal involvement was 12 clock hours (range, 3 to 12 clock hours), resulting in a residual limbal stem cell deficiency of 6 clock hours (range, 0 to 12 clock hours) at 1 year. Most common complications were glaucoma and cataract. Corneal ulcers developed in 2 eyes, and keratolimbal graft was performed in 1 patient. Grade VI injuries had significantly worse outcome than the lower-grade injuries. The course and outcome of ocular alkali burns depends on effective first aid (including a thorough eyewash), age, initial grade of injury, response to treatment, prevention of secondary infection, and control of glaucoma. Despite appropriate treatment, these eyes responded poorly and carried a guarded visual prognosis. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Altering surface characteristics of polypropylene mesh via sodium hydroxide treatment.

    Science.gov (United States)

    Regis, Shawn; Jassal, Manisha; Mukherjee, Nilay; Bayon, Yves; Scarborough, Nelson; Bhowmick, Sankha

    2012-05-01

    Incisional hernias represent a serious and common complication following laparotomy. The use of synthetic (e.g. polypropylene) meshes to aid repair of these hernias has considerably reduced recurrence rates. While polypropylene is biocompatible and has a long successful clinical history in treating hernias and preventing reherniation, this material may suffer some limitations, particularly in challenging patients at risk of wound failure due to, for example, an exaggerated inflammation reaction, delayed wound healing, and infection. Surface modification of the polypropylene mesh without sacrificing its mechanical properties, critical for hernia repair, represents one way to begin to address these clinical complications. Our hypothesis is treatment of a proprietary polypropylene mesh with sodium hydroxide (NaOH) will increase in vitro NIH/3T3 cell attachment, predictive of earlier and improved cell colonization and tissue integration of polypropylene materials. Our goal is to achieve this altered surface functionality via enhanced removal of chemicals/oils used during material synthesis without compromising the mechanical properties of the mesh. We found that NaOH treatment does not appear to compromise the mechanical strength of the material, despite roughly a 10% decrease in fiber diameter. The treatment increases in vitro NIH/3T3 cell attachment within the first 72 h and this effect is sustained up to 7 days in vitro. This research demonstrates that sodium hydroxide treatment is an efficient way to modify the surface of polypropylene hernia meshes without losing the mechanical integrity of the material. This simple procedure could also allow the attachment of a variety of biomolecules to the polypropylene mesh that may aid in reducing the complications associated with polypropylene meshes today. Copyright © 2012 Wiley Periodicals, Inc.

  14. Magnesium hydroxide in ibuprofen tablet reduces the gastric mucosal tolerability of ibuprofen.

    Science.gov (United States)

    Mäenpää, Jukka; Tarpila, Anneli; Jouhikainen, Taneli; Ikävalko, Harri; Löyttyniemi, Eliisa; Perttunen, Kristiina; Neuvonen, Pertti J; Tarpila, Simo

    2004-01-01

    The study was designed to compare the gastrointestinal tolerability of a magnesium hydroxide-containing ibuprofen tablet (buffered ibuprofen) and the conventional ibuprofen tablet in healthy volunteers. Magnesium hydroxide has been shown to increase the rate of absorption of ibuprofen. A double blind, randomized, 2-period crossover study design was used. Twenty healthy men ingested 800 mg ibuprofen 3 times daily either in conventional tablets (2 doses of 400 mg) or in tablets containing magnesium hydroxide (2 doses of 400 mg ibuprofen and 200 mg magnesium hydroxide). On the 5th day only the morning dose was administered. Endoscopy was performed at baseline and on the 5th day in both treatments 2 hours after the last dose, and gastric pH was determined. In addition, plasma concentrations of ibuprofen were determined up to 90 minutes. The magnesium hydroxide-containing formulation increased the number of subjects evincing erosions in gastric corpus and antrum. In the gastric corpus 2 and 7 volunteers had erosions after conventional and buffered ibuprofen, respectively (P = 0.08). In the gastric antrum 5 and 13 volunteers showed erosions after conventional and buffered ibuprofen, respectively (P = 0.02). There was a trend toward faster absorption of ibuprofen when given together with magnesium hydroxide. The difference was not however statistically significant. Prolonged use of magnesium hydroxide together with high doses of ibuprofen should be avoided, because the combination may incur a higher risk of gastrointestinal irritation.

  15. The effects of oral magnesium hydroxide administration on rumen fluid in cattle.

    Science.gov (United States)

    Smith, Geoffrey W; Correa, Maria T

    2004-01-01

    This study was conducted to determine the effects of oral magnesium hydroxide administration on rumen fluid in cattle. Six lactating Holstein cows (4-7 years of age) with rumen fistulas were studied. Cattle were randomly assigned to receive boluses of magnesium hydroxide (162 g) or a powdered form (450 g dissolved in 3.5 L of water) PO daily for 3 days. Analysis of rumen fluid, blood gas tensions, and pH and measurement of serum magnesium concentrations were conducted daily. The study was discontinued after 72 hours, or sooner if rumen pH exceeded 8.0. After at least 3 weeks, the study was repeated with each cow receiving the other form of magnesium hydroxide (powder or bolus). Compared with baseline rumen pH (mean +/- SD: 6.22 +/- 0.28), magnesium hydroxide boluses caused a significant increase (P magnesium hydroxide decreased rumen protozoal numbers and increased methylene blue reduction times compared with baseline values. There was no change in blood pH, bicarbonate, or base excess values. Serum magnesium concentrations were significantly increased (P magnesium hydroxide powder. The results of this study indicate that magnesium hydroxide has a potent alkalinizing effect on rumen pH and significantly decreases rumen microbial activity.

  16. Evaluation of antibacterial effects of different calcium hydroxide compositions on planktonic Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Mahdi Tabrizizadeh

    2012-01-01

    Full Text Available Background and Aims: Calcium hydroxide has a pronounced antimicrobial activity against most of the bacterial species found in infected root canals and endodontic infections. It is one of the most frequently used intracanal medications in endodontic therapy. The objective of this study was to determine the antimicrobial efficacy of six calcium hydroxide formulations (mixed with saline, lidocaine 2%, chlorhexidine 2%, chlorhexidine 0.2%, Iodine Potassium iodide (IKI 2%, and glycerin on Enterococcus faecalis using agar diffusion test.Materials and Methods: Twelve culture plates were incubated with Enterococcus faecalis. Five cavities were made in each plate with 5 mm diameter and 4 mm depth. Two plates were randomly considered for each calcium hydroxide formulation and filled completely with creamy mixture of tested materials. The plates were incubated at 37ºC for 48 hours. The diameter of inhibition zone around each well was recorded in millimetres and data were submitted to ANOVA and Tukey tests.Results: The results of this study showed that all tested calcium hydroxide pastes had good antimicrobial activity. The antimicrobial activity of calcium hydroxide mixed with lidocaine, chlorhexidine 2% and IKI 2% were significantly greater than that of calcium hydroxide mixed with saline (P0.01.Conclusion: Considering the results of this study, lidocaine 2%, chlorhexidine 2% and IKI 2% are suggested to be used for preparation of calcium hydroxide paste. Further studies with different methods are needed for confirming these results.

  17. FT-Raman spectroscopy of calcium hydroxide medicament in root canals.

    Science.gov (United States)

    Kwon, T Y; Fujishima, T; Imai, Y

    2004-07-01

    To investigate chemical changes in calcium hydroxide introduced into human root canals as a medicament using Fourier transform-(FT) Raman spectroscopy. Ten necrotic maxillary anterior teeth were selected in 10 patients. The teeth were divided into five treatment groups, according to the survey time. Root canal instrumentation was performed with hand instruments until the master apical file was size 40. Calcium hydroxide paste, in a 1 : 1.25 mixture by weight of powder and distilled water, was introduced directly into the root canal with a lentulo-spiral filler and then condensed with a finger plugger. The access cavity was sealed with a temporary dressing. After 2 and 4 days, then 2, 4 and 6 weeks, the calcium hydroxide paste was sampled with a K-file and then analysed using FT-Raman spectroscopy. The excitation source was an Nd : YAG laser with an excitation wavelength of 1064 nm. All spectra were taken with a laser power of 200 mW, 275-1185 scans, and 4 cm(-1) resolution. The conversion of calcium hydroxide to calcium carbonate was calculated on the basis of the spectral data obtained from the mixtures of both compounds. The calcium hydroxide paste in the apical region showed weak bands at 1088 and 284 cm(-1), in addition to bands associated with calcium hydroxide. The weak bands, assigned to calcium carbonate, became stronger with time. Calcium carbonate content increased rapidly in the first 2 days and then tended to increase slowly. Approximately 11% of the calcium hydroxide at the apical portion of the canal was converted to calcium carbonate after 6 weeks. However, little alteration of the paste was noticed in the samples from the middle portion of the canal. Calcium hydroxide medicament in root canals became transformed into calcium carbonate in the apical region within 2 days. Although the transformation continued with time, approximately 90% of the calcium hydroxide remained unchanged after 6 weeks.

  18. PROCESS FOR SEPARATING PLUTONIUM BY REPEATED PRECIPITATION WITH AMPHOTERIC HYDROXIDE CARRIERS

    Science.gov (United States)

    Faris, B.F.

    1960-04-01

    A multiple carrier precipitation method is described for separating and recovering plutonium from an aqueous solution. The hydroxide of an amphoteric metal is precipitated in an aqueous plutonium-containing solution. This precipitate, which carries plutonium, is then separated from the supernatant liquid and dissolved in an aqueous hydroxide solution, forming a second plutonium- containing solution. lons of an amphoteric metal which forms an insoluble hydroxide under the conditions existing in this second solution are added to the second solution. The precipitate which forms and which carries plutonium is separated from the supernatant liquid. Amphoteric metals which may be employed are aluminum, bibmuth, copper, cobalt, iron, lanthanum, nickel, and zirconium.

  19. Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: 27Al NMR and pH-stat studies.

    Science.gov (United States)

    Wilson, G E; Falzone, C J; Johnson, R; Lee, H K

    1985-10-01

    Neutralization of mixtures of aluminum hydroxide-magnesium hydroxide gels and of magaldrate by hydrochloric acid were studied by 27Al NMR under conditions of both equilibrium and kinetic control. Under conditions where equilibrium has been attained, an aluminum NMR signal is detectable for suspensions of the mixed gels and magaldrate only after enough acid has been added to exhaust the acid-neutralizing capacity of the magnesium hydroxide. Mixed gels seem to form several soluble aluminum-containing species as neutralization proceeds. Under the conditions of the modified Beekman neutralization procedure, in which the species concentrations reflect neutralization kinetics, mixed gels show a sharp burst of the hexaaquoaluminum cation as acid is added followed by a slow loss of that cation from solution and an accompanying slow rise in pH. Magaldrate shows a steady increase in the hexaaquoaluminum cation with added acid. Differences between magaldrate and mixed gels are also apparent in pH-stat titrations in which magaldrate displays a biphasic response, contrasting to the two burst phases with an intervening lag phase observed for mixed gels. The results of the 27Al NMR and pH-stat titrations are consistent with the hypotheses that magaldrate is a homogeneous substance with a hydrotalcite-like structure and that mixed gels consist of a magnesium hydroxide core surrounded by aluminum hydroxide.

  20. Synthesis and crystal structure of terbium(III) meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}); Synthese und Kristallstruktur von Terbium(III)-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6})

    Energy Technology Data Exchange (ETDEWEB)

    Nikelski, Tanja; Schleid, Thomas [Institut fuer Anorganische Chemie der Universitaet Stuttgart (Germany)

    2003-06-01

    The terbium meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) is obtained as single crystals by the reaction of terbium, Tb{sub 4}O{sub 7} and TbCl{sub 3} with an excess of B{sub 2}O{sub 3} in gastight sealed platinum ampoules at 950 C after three weeks. The compound appears to be air- and water-resistant and crystallizes as long, thin, colourless needles which tend to growth-twinning due to their marked fibrous habit. The crystal structure of Tb(BO{sub 2}){sub 3} (orthorhombic, Pnma; a = 1598.97(9), b = 741.39(4), c = 1229.58(7) pm; Z = 16) contains strongly corrugated oxoborate layers {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} built of vertex-linked [BO{sub 4}]{sup 5-} tetrahedra (d(B-O) = 143 - 154 pm, and angsph;(O-B-O) = 102-115 ) which spread out parallel (100). The four crystallographically different Tb{sup 3+} cations all exhibit coordination numbers of eight towards the oxygen atoms (d(Tb-O) = 228-287 pm). The corresponding metal cation polyhedra [TbO{sub 8}]{sup 13+} too convene to layers (composition: {sub {infinity}}{sup 2}{l_brace}(Tb{sub 2}O{sub 11}){sup 16-}{r_brace}) which are likewise oriented parallel to the (100) plane. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Das Terbium-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) entsteht einkristallin bei der Reaktion von Terbium, Tb{sub 4}O{sub 7} und TbCl{sub 3} mit einem Ueberschuss von B{sub 2}O{sub 3} in gasdicht verschlossenen Platinampullen nach drei Wochen bei 950 C. Die Verbindung ist luft- und wasserstabil und faellt in langen, duennen, farblosen Nadeln an, die aufgrund ihres ausgepraegt faserigen Habitus zur Wachstumsverzwillingung neigen. Die Kristallstruktur von Tb(BO{sub 2}){sub 3} (orthorhombisch, Pnma; a = 1598, 97(9), b = 741, 39(4), c = 1229, 58(7) pm; Z = 16) enthaelt parallel (100) verlaufende, stark gewellte Oxoborat-Schichten {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} aus

  1. METHOD FOR RECOVERING PLUTONIUM VALUES FROM SOLUTION USING A BISMUTH HYDROXIDE CARRIER PRECIPITATE

    Science.gov (United States)

    Faris, B.F.

    1961-04-25

    Carrier precipitation processes for separating plutonium values from aqueous solutions are described. In accordance with the invention a bismuth hydroxide precipitate is formed in the plutonium-containing solution, thereby carrying plutonium values from the solution.

  2. Safety Assessment of Alumina and Aluminum Hydroxide as Used in Cosmetics.

    Science.gov (United States)

    Becker, Lillian C; Boyer, Ivan; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2016-11-01

    This is a safety assessment of alumina and aluminum hydroxide as used in cosmetics. Alumina functions as an abrasive, absorbent, anticaking agent, bulking agent, and opacifying agent. Aluminum hydroxide functions as a buffering agent, corrosion inhibitor, and pH adjuster. The Food and Drug Administration (FDA) evaluated the safe use of alumina in several medical devices and aluminum hydroxide in over-the-counter drugs, which included a review of human and animal safety data. The Cosmetic Ingredient Review (CIR) Expert Panel considered the FDA evaluations as part of the basis for determining the safety of these ingredients as used in cosmetics. Alumina used in cosmetics is essentially the same as that used in medical devices. This safety assessment does not include metallic or elemental aluminum as a cosmetic ingredient. The CIR Expert Panel concluded that alumina and aluminum hydroxide are safe in the present practices of use and concentration described in this safety assessment. © The Author(s) 2016.

  3. Antimicrobial properties of calcium hydroxide dressing when used for long-term application: A systematic review.

    Science.gov (United States)

    Sharma, Garima; Ahmed, Hany Mohamed Aly; Zilm, Peter S; Rossi-Fedele, Giampiero

    2017-11-23

    This review aims to evaluate the antimicrobial efficacy of calcium hydroxide against endodontic pathogens when used for 7 days or longer. A systematic electronic literature search was performed in the PubMed, Embase and EBSCO Dentistry & Oral Sciences Source databases using appropriate key words to identify investigations written in the English language that examined the association between the contact time of intracanal calcium hydroxide dressing and its antimicrobial properties. There were no exclusions based on study design. The search yielded 6993 publications. After duplicate removal, 5913 publications were identified and 11 studies met the inclusion criteria. Results showed that the antimicrobial effect of calcium hydroxide for contact times ranging between seven and 45 days is comparable. Two studies demonstrated contradictory findings when exposure was extended to more than 45 days. Future studies are warranted to investigate and optimise calcium hydroxide application for longer periods and identify the potential benefits of its use in clinical settings. © 2017 Australian Society of Endodontology Inc.

  4. Potential for layered double hydroxides-based, innovative drug delivery systems

    National Research Council Canada - National Science Library

    Zhang, Kai; Xu, Zhi Ping; Lu, Ji; Tang, Zhi Yong; Zhao, Hui Jun; Good, David A; Wei, Ming Qian

    2014-01-01

    Layered Double Hydroxides (LDHs)-based drug delivery systems have, for many years, shown great promises for the delivery of chemical therapeutics and bioactive molecules to mammalian cells in vitro and in vivo...

  5. Antimicrobial effect of calcium hydroxide as endo intracanal dressing on Streptococcus viridans

    Directory of Open Access Journals (Sweden)

    Nanik Zubaidah

    2008-03-01

    Full Text Available Calcium hydroxide had been used as the intra-canal dressing in endodontic treatment due to its high alkaline and antimicrobial capacity. It can also dissolve the necrotic tissue, prevent dental root resorbtion and regenerate a new hard tissue. The aim of this study was to determine the concentration of calcium hydroxide which had the highest antimicrobial effect on Streptococcus viridans. Samples were divided into 5 groups; each group consisted of 8 samples with different concentration of calcium hydroxide. Group I: 50%, group II: 55, Group III: 60%, Group IV: 65%, Group V: 70%. The antimicrobial testing was performed using diffusion method against Streptococcus viridans. The result of susceptibility test was showed by the inhibition zone diameter which measured with caliper (in millimeter. We analyzed the data using One-Way ANOVA test with significant difference 0.05 and subsequently LSD test. The study showed that calcium hydroxide with concentration 60% has the highest antimicrobial effect.

  6. [Successful treatment of hemorrhagic cystitis after radiation therapy with intravesical instillation of aluminium hydroxide gel and magnesium hydroxide: report of a case].

    Science.gov (United States)

    Kawamura, Norihiko; Kakuta, Yoichi; Fukuhara, Sinichiro; Imazu, Tetsuo; Hara, Tsuneo; Yamaguchi, Seiji

    2008-03-01

    A 77-year-old man was admitted to our hospital due to macrohematuria and bladder tamponade. Bladder hemorrhage caused by radiation therapy had not improved after bladder lavage, intravesical drip infusion, medication of hemostatics, and transurethral coagulation. Bladder hemorrhage had completely disappeared 7 days after the intravesical instillation of 50-100 ml aluminium hydroxide gel and magnesium hydroxide for an hour per day. This method is easy and can be performed without complications. This method might be useful as first-line therapy in the case of severe bladder hemorrhage.

  7. Synthesis and characterization of biodegradable microcapsules for the controlled delivery of calcium hydroxide.

    Science.gov (United States)

    Han, Bing; Wang, Xiaoyan; Gao, Xuejun; Liu, Jiguang; Liang, Fuxin; Qu, Xiaozhong; Yang, Zhenzhong

    2011-10-01

    This study aimed to synthesize and characterize biodegradable microcapsules based on poly(lactic acid) (PLA) and ethylcellulose (EC) for a controlled delivery of calcium hydroxide. Phase separation technique was adopted to synthesize calcium hydroxide-loaded PLA/EC microcapsules. Four PLA/EC blends (4/1, 1/1, 1/4, pure EC) were used as shell materials and the input ratio of calcium hydroxide to shell polymer was 4:1 for all microcapsules. The morphology and composition were studied using SEM-EDS and TEM. Particle size distribution, glass-transition temperature, drug loading, and encapsulation efficiency were characterized. In vitro release of the microcapsules was evaluated using a pH microelectrode and an auto-biochemistry analyzer. SEM images of microcapsules showed uniform spherical structures with smooth surfaces. Core-shell, hetero-structures were confirmed using TEM. The presence of calcium in the microcapsules was verified with EDS. Pure calcium hydroxide was 160 nm in diameter and the particle size of the microcapsules ranged between 500 nm and 4 μm. With an increase of PLA in PLA/EC blend, the size of microcapsules increased accordingly. Encapsulation efficiency of these microcapsules was higher than 57% and drug loading was higher than 80%, which were not significantly different among four microcapsules. Pure calcium hydroxide powder was used as a control and 90% was released within 48 h, while release of calcium hydroxide from microcapsules took between 168 and 456 h, depending on the PLA/EC ratio. Compared with calcium hydroxide powder, the calcium hydroxide-loaded microcapsules showed a sustained and prolonged release, which could be controlled via the regulation of the PLA/EC ratio. Copyright © 2011 Wiley Periodicals, Inc.

  8. Nickel hydroxides and related materials: a review of their structures, synthesis and properties

    OpenAIRE

    Hall, David S.; Lockwood, David J.; Bock, Christina; MacDougall, Barry R.

    2015-01-01

    This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the inco...

  9. 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...

  10. Calcium hydroxide as low cost adsorbent for the effective removal of indigo carmine dye in water

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2017-02-01

    Full Text Available Adsorption of indigo carmine dye onto calcium hydroxide was investigated in this work. The variation in the pH, adsorbent dose, dye concentration, duration and the temperature was evaluated. Adsorption of indigo carmine dye onto calcium hydroxide was effective at pH 12 (50 min and follows Langmuir-type isotherm behaviour. The adsorption process follows pseudo-second order rate kinetics. Enthalpy, entropy, free energy and the activation energy parameters have been reported.

  11. Calcium hydroxide as low cost adsorbent for the effective removal of indigo carmine dye in water

    OpenAIRE

    Thimmasandra Narayan Ramesh; Devarahosahally Veeranna Kirana; Ashwathaiah Ashwini; T.R. Manasa

    2017-01-01

    Adsorption of indigo carmine dye onto calcium hydroxide was investigated in this work. The variation in the pH, adsorbent dose, dye concentration, duration and the temperature was evaluated. Adsorption of indigo carmine dye onto calcium hydroxide was effective at pH 12 (50 min) and follows Langmuir-type isotherm behaviour. The adsorption process follows pseudo-second order rate kinetics. Enthalpy, entropy, free energy and the activation energy parameters have been reported.

  12. The Influence of Limestone and Calcium Hydroxide Addition in Asphalt Concrete Mixture

    OpenAIRE

    Gunaran Danny; Nasus K. Y; Napitupulu J. P. F; Amelia Makmur

    2016-01-01

    As time passes, flood often occurs in the area of Gunung Sahari, Jakarta Utara. The flood damages concrete asphalt mixture and it needs particular improvement. Therefore, the purpose of this research is to know the effects of the added combination of limestone and calcium hydroxide on concrete asphalt mixture as a filler resistant to flood. Concrete asphalt mixture that filled with the combination of limestone and calcium hydroxide is a mixture that is made with non-uniform aggregat gradation...

  13. Technical aspects involved in the removal of calcium hydroxide intracanal medication

    OpenAIRE

    Silva, Luciana Jorge Moraes; BRAGA, Roberto Ruggiero; Pessoa, Oscar Faciola

    2014-01-01

    The search for an effective method of microbial control has been a constant concern in endodontics. The aim of this literature review was to discuss the technical aspects related to the removal of intracanal calcium hydroxide. As an adjunct to sanifi cation and microbial control, calcium hydroxide [Ca(OH)2] intracanal medication is more suitable in cases of pulp necrosis and chronic periapical lesions. However, it is not easily removed from the root canal, and its residue can affect the inter...

  14. Considerable differences in vaccine immunogenicities and efficacies related to the diluent used for aluminum hydroxide adjuvant.

    Science.gov (United States)

    Lin, Lin; Ibrahim, Ashraf S; Avanesian, Valentina; Edwards, John E; Fu, Yue; Baquir, Beverlie; Taub, Rebecca; Spellberg, Brad

    2008-03-01

    We are developing an anticandidal vaccine using the recombinant N terminus of Als3p (rAls3p-N). We report that although more rAls3p-N was bound by aluminum hydroxide diluted in saline than by aluminum hydroxide diluted in phosphate-buffered saline (PBS), its immunogenicity and efficacy were superior in PBS. Thus, protein binding, by itself, may not predict the efficacy of some vaccines with aluminum adjuvants.

  15. [Sorption of nitrobenzene to anionic surfactant modified layered double hydroxides].

    Science.gov (United States)

    Xia, Yan; Zhu, Run-Liang; Tao, Qi; Liu, Han-Yang

    2013-01-01

    Sodium dodecyl sulfate (SDS) modified MgAl layered double hydroxides (LDHs) were synthesized at different surfactant concentrations (0.5-2.0 TAEC) by the co-precipitation method. The LDH-DS samples obtained were characterized by powder X-ray diffraction and FT-IR spectroscopy. The results showed that SDS was successfully intercalated into the interlayer of the LDH, and the basal spacing was expanded from 0.80 nm to 3.98 nm. The intercalated SDS was considered consistent with a paraffin bilayers arrangement. The sorption of nitrobenzene on LDH-DS was examined, and the results showed that linear model could fit the sorption isotherms well (R2 > 0.99), which implied a partitioning sorption process. The sorption coefficient of nitrobenzene (K(d)) on LDH-DS was positively related to the DS - loading amount, but the organic carbon content normalized sorption coefficient of nitrobenzene (K(oc)) was shown to remain relatively constant. The sorption thermodynamics results showed that the sorption of nitrobenzene on LDH-DS was an endothermic process, and the increase of entropy was the driving force for the sorption process.

  16. Comparison of final irrigation techniques in removal of calcium hydroxide.

    Science.gov (United States)

    Yücel, Ali Çağın; Gürel, Melek; Güler, Eda; Karabucak, Bekir

    2013-12-01

    The aim of this study was to compare new irrigation systems with a conventional irrigation technique for the removal of inter-appointment calcium hydroxide [Ca(OH)2 ]. Forty-seven extracted human single-rooted teeth were instrumented, and Ca(OH)2 paste was placed into root canals by using a lentulo spiral at the apical third. Teeth were randomly divided into three groups according to different irrigation protocols using a 30-gauge slot-tipped needle, EndoVac system and ProUltra® PiezoFlow™ ultrasonic irrigation system. Scanning electron microscopic images of the selected root canal surfaces (cervical, middle and apical third) were evaluated using a 5-grade scale. The influence of the irrigation system was evaluated using a two-way analysis of variance test and Tukey's test. The EndoVac and PiezoFlow groups demonstrated the lowest scale values (cleanest canals); however, there was no statistical difference between these two groups. The conventional irrigation group exhibited significantly higher scores (P ultrasonic irrigation systems improved the removal of the intracanal medicament resulting in cleaner root canal walls. © 2011 The Authors. Australian Endodontic Journal © 2011 Australian Society of Endodontology.

  17. Potassium hydroxide pulping of rice straw in biorefinery initiatives.

    Science.gov (United States)

    Jahan, M Sarwar; Haris, Fahmida; Rahman, M Mostafizur; Samaddar, Purabi Rani; Sutradhar, Shrikanta

    2016-11-01

    Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Defluoridation from aqueous solutions by granular ferric hydroxide (GFH).

    Science.gov (United States)

    Kumar, Eva; Bhatnagar, Amit; Ji, Minkyu; Jung, Woosik; Lee, Sang-Hun; Kim, Sun-Joon; Lee, Giehyeon; Song, Hocheol; Choi, Jae-Young; Yang, Jung-Seok; Jeon, Byong-Hun

    2009-02-01

    This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions. Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24h), initial fluoride concentration (1-100 mgL(-1)), temperature (10 and 25 degrees C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mgg(-1). The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water.

  19. Bromate removal from water by granular ferric hydroxide (GFH).

    Science.gov (United States)

    Bhatnagar, Amit; Choi, Yanghun; Yoon, Yeojoon; Shin, Yongsoon; Jeon, Byong-Hun; Kang, Joon-Wun

    2009-10-15

    The feasibility of granular ferric hydroxide (GFH) for bromate removal from water has been studied. Batch experiments were performed to study the influence of various experimental parameters such as effect of contact time, initial bromate concentration, temperature, pH and effect of competing anions on bromate removal by GFH. The adsorption kinetics indicates that uptake rate of bromate was rapid at the beginning and 75% adsorption was completed in 5 min and equilibrium was achieved within 20 min. The sorption process was well described by pseudo-second-order kinetics. The maximum adsorption potential of GFH for bromate removal was 16.5 mg g(-1) at 25 degrees C. The adsorption data fitted well to the Langmuir model. The increase in OH peak and absence of Br-O bonding in FTIR spectra indicate that ion-exchange was the main mechanism during bromate sorption on GFH. The effects of competing anions and solution pHs (3-9) were negligible. Results of the present study suggest that GFH can be effectively utilized for bromate removal from drinking water.

  20. 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

  1. Waste metal hydroxide sludge as adsorbent for a reactive dye.

    Science.gov (United States)

    Santos, Sílvia C R; Vílar, Vítor J P; Boaventura, Rui A R

    2008-05-30

    An industrial waste sludge mainly composed by metal hydroxides was used as a low-cost adsorbent for removing a reactive textile dye (Remazol Brilliant Blue) in solution. Characterization of this waste material included chemical composition, pH(ZPC) determination, particle size distribution, physical textural properties and metals mobility under different pH conditions. Dye adsorption equilibrium isotherms were determined at 25 and 35 degrees C and pH of 4, 7 and 10 revealing reasonably fits to Langmuir and Freundlich models. At 25 degrees C and pH 7, Langmuir fit indicates a maximum adsorption capacity of 91.0mg/g. An adsorptive ion-exchange mechanism was identified from desorption studies. Batch kinetic experiments were also conducted at different initial dye concentration, temperature, adsorbent dosage and pH. A pseudo-second-order model showed good agreement with experimental data. LDF approximation model was used to estimate homogeneous solid diffusion coefficients and the effective pore diffusivities. Additionally, a simulated real effluent containing the selected dye, salts and dyeing auxiliary chemicals, was also used in equilibrium and kinetic experiments and the adsorption performance was compared with aqueous dye solutions.

  2. An integrated logic system for time-resolved fluorescent "turn-on" detection of cysteine and histidine base on terbium (III) coordination polymer-copper (II) ensemble.

    Science.gov (United States)

    Xue, Shi-Fan; Lu, Ling-Fei; Wang, Qi-Xian; Zhang, Shengqiang; Zhang, Min; Shi, Guoyue

    2016-09-01

    Cysteine (Cys) and histidine (His) both play indispensable roles in many important biological activities. An enhanced Cys level can result in Alzheimer's and cardiovascular diseases. Likewise, His plays a significant role in the growth and repair of tissues as well as in controlling the transmission of metal elements in biological bases. Therefore, it is meaningful to detect Cys and His simultaneously. In this work, a novel terbium (III) coordination polymer-Cu (II) ensemble (Tb(3+)/GMP-Cu(2+)) was proposed. Guanosine monophosphate (GMP) can self-assemble with Tb(3+) to form a supramolecular Tb(3+) coordination polymer (Tb(3+)/GMP), which can be suited as a time-resolved probe. The fluorescence of Tb(3+)/GMP would be quenched upon the addition of Cu(2+), and then the fluorescence of the as-prepared Tb(3+)/GMP-Cu(2+) ensemble would be restored again in the presence of Cys or His. By incorporating N-Ethylmaleimide and Ni(2+) as masking agents, Tb(3+)/GMP-Cu(2+) was further exploited as an integrated logic system and a specific time-resolved fluorescent "turn-on" assay for simultaneously sensing His and Cys was designed. Meanwhile it can also be used in plasma samples, showing great potential to meet the need of practical application. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Synthesis and photoluminescence properties of cerium-doped terbium-yttrium aluminum garnet phosphor for white light-emitting diodes applications

    Science.gov (United States)

    Wang, Jun; Han, Tao; Lang, Tianchun; Tu, Mingjing; Peng, Lingling

    2015-11-01

    Cerium-doped terbium-yttrium aluminum garnet phosphors were synthesized using the solid-state reaction method. The crystalline phase, morphology, and photoluminescence properties were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), and fluorescence spectrophotometer, respectively. The XRD results indicate that with an increase of the amount of x (Tb3+), all of the samples have a pure garnet crystal structure without secondary phases. The SEM images reveal that the samples are composed of sphere-like crystallites, which exhibit different degrees of agglomeration. The luminescent properties of Ce ions in )Al5O12∶Ce0.1 have been studied, and it was found that the emission band shifted toward a longer wavelength. The redshift is attributed to the lowering of the 5d energy level centroid of Ce, which can be explained by the nephelauxetic effect and compression effect. These phosphors were coated on blue light-emitting diode (LED) chips to fabricate white light-emitting diodes (WLEDs), and their color-rendering indices, color temperatures, and luminous efficiencies were measured. As a consequence of the addition of Tb, the blue LED pumped )Al5O12∶Ce0.1 phosphors WLEDs showed good optical properties.

  4. Study on the fluorescent enhancement effect in terbium-gadolinium-protein-sodium dodecyl benzene sulfonate system and its application on sensitive detection of protein at nanogram level.

    Science.gov (United States)

    Sun, Changxia; Yang, Jinghe; Wu, Xia; Liu, Shufang; Su, Benyu

    2004-08-01

    The co-luminescence effect in a terbium-gadolinium-protein-sodium dodecyl benzene sulfonate (SDBS) system is reported here. Based on it, the sensitive quantitative analysis of protein at nanogram levels is established. The co-luminescence mechanism is studied using fluorescence, resonance light scattering (RLS), absorption spectroscopy and NMR measurement. It is considered that protein could be unfolded by SDBS, then a efficacious intramolecular fluorescent energy transfer occurs from unfolded protein to rare earth ions through SDBS acting as a "transfer bridge" to enhance the emission fluorescence of Tb3+ in this ternary complex of Tb-SDBS-BSA, where energy transfer from protein to SDBS by aromatic ring stacking is the most important step. Cooperating with the intramolecular energy transfer above is the intermolecular energy transfer between the simultaneous existing complexes of both Tb3+ and Gd3+. The fluorescence quantum yield is increased by an energy-insulating sheath, which is considered to be another reason for the resulting enhancement of the fluorescence. Förster theory is used to calculate the distribution of enhancing factors and has led to a greater understanding of the mechanisms of energy transfer.

  5. [Studies on luminescence properties of seven ternary complexes of terbium with 1,10-phenanthroline and benzoic acid and its derivatives].

    Science.gov (United States)

    Gao, Zhi-hua; Wang, Shu-ping; Liu, Cui-ge; Ma, Rui-xia; Wang, Rui-fen

    2006-04-01

    Seven ternary complexes of Tb(III) were synthesized with benzoic acid (BA), o-, m-, p-methylbenzoic acid (o-MBA, m-MBA, p-MBA), and o-, m-, p-methoxybenzoic acid (o-MOBA, m-MOBA, p-MOBA) as the first ligand, and 1,10-phenanthroline (phen) as the second ligand. The content of C, H and N were measured by using a Flash-EA model 1112 elemental analyzer. Excitation and luminescence spectra of the title solid complexes were recorded by using a Hitachi F-4500 fluorescence spectrophotometer at room temperature. The effects of different varieties and different positions of replacing benzoic acid as the first ligand on fluorescence properties of the ternary complexes of terbium were discussed. The results indicated that the intensity of 5D4-->7F6 (489 nm) and 5D4-->7F5 (545 nm) of substituting benzoic acid complexes was stronger than benzoic acid. Three ternary complexes of Tb(III) with o-, m-, p-methylbenzoic acid showed emission intensity in the consecution: Tb(o-MBA)3 phenMOBA)3phen x H2O>Tb(m-MOBA)3phen x H2O>Tb(p-MOBA)3 phen.

  6. Removal of fluoride from water using iron oxide-hydroxide nanoparticles.

    Science.gov (United States)

    Raul, Prasanta Kumar; Devi, Rashmi Rekha; Umlong, Iohborlang M; Banerjee, Saumen; Singh, Lokendra; Purkait, Mihir

    2012-05-01

    A novel and facile method for the synthesis of uniform stoichiometric powder form of non-magnetic iron oxide-hydroxide nanoparticles with spherical morphology and its application for defluoridation of drinking water is reported. X-ray powder diffraction analysis (XRD), BET surface area, FTIR, field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) images were used to characterize nanoscale iron oxide-hydroxide. Transmission electron microscopy (TEM) image revealed the formation of iron oxide-hydroxide nanoparticles with spherical morphology. The iron oxide-hydroxide nanoparticles showed an excellent ability to remove fluoride (F-) from contaminated water over a wide range of pH. The influences of temperature, stirring speed, pH, adsorbent dose and contact time were studied. The equilibrium data were tested with various isotherm models and finally, a calculation procedure was reported for the calculation of adsorbent requirement. The fluoride adsorbed nanoparticles was regenerated upto 70% using sodium hydroxide or hydrochloric acid solution. The iron oxide-hydroxide nanoparticles can be used as an effective and replicable adsorbent media for defluoridation of water in presence of competing anions like chloride, iodate, iodide and sulphate.

  7. Nickel hydroxide ageing time influence on its solubility in water acidified with sulphuric acid.

    Science.gov (United States)

    Osińska, Małgorzata; Stefanowicz, Tadeusz; Paukszta, Dominik

    2004-08-30

    Nickel hydroxide samples freshly settled as well as stored over 1 month, 2 months and 6.5 years were examined for their solubility rate in diluted H2SO4 solutions of pH 1.9 and 2.8 as a function of time. Samples with a longer ageing history dissolved less readily than freshly settled ones. It was determined that the resistance to dissolving rose with sample ageing time and the solubility of the 6.5 years stored sample was particularly low. X-ray examination evidenced that during storage the crystallinity of Ni(OH)2 subsequently rose. The parallelity of both time-dependent phenomena allows the conclusion that with nickel hydroxide ageing the transformation of disordered nickel hydroxide species into crystalline Ni(OH)2 (without phase changes) is responsible for increasing nickel hydroxide resistance to dissolving in acidic solutions. Such decrease of nickel hydroxide solubility with ageing in case of waste nickel hydroxide, is worth to notice in a view of environment protection against pollution with electroplating waste.

  8. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application

    Science.gov (United States)

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-01-01

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal−air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application. PMID:28272443

  9. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application

    Science.gov (United States)

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-03-01

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

  10. Development of polymer nanocomposites based on layered double hydroxides

    Directory of Open Access Journals (Sweden)

    Sipusic, J.

    2009-05-01

    Full Text Available Polymeric nanocomposites are commonly considered as systems composed of a polymeric matrix and - usually inorganic - filler. The types of nanofillers are indicated in Fig. 1. Beside wellknown layered silicate fillers, recent attention is attracted to layered double hydroxide fillers (LDH, mainly of synthetic origin. The structure of LDH is based on brucite, or magnesium hydroxide, Mg(OH2 and is illustrated in Fig. 2. The modification of LDHs is commonly done by organic anions, to increase the original interlayer distance and to improve the organophilicity of the filler, keeping in mind their final application as fillers for, usually hydrophobic, polymer matrices. We have used the modified rehydration procedure for preparing organically modified LDH. The stoichiometric quantities of Ca33Al2O6, CaO and benzoic (B (or undecenoic (U acid were mixed with water and some acetone. After long and vigorous shaking, the precipitated fillers were washed, dried and characterized. X-ray diffraction method (XRD has shown the increase of the original interlayer distance for unmodified LDH (OH–-saturated of 0.76 nm to the 1.6 nm in LDH-B or LDH-U fillers (Fig. 3. Infrared spectroscopy method (FTIR has confirmed the incorporation of benzoic anion within the filler layers (Fig. 4. For the preparation of LDH-B and LDH-U composites with polystyrene (PS, poly(methyl methacrylate (PMMA and copolymer (SMMA matrices, a two-step in situ bulk radical polymerization was selected (Table 1 for recipes, azobisisobutyronitrile as initiator, using conventional stirred tank reactor in the first step, and heated mold with the movable wall (Fig. 6 in the second step of polymerization. All the prepared composites with LDH-U fillers were macroscopically phase-separated, as was the PMMA/LDH-B composite.PS/LDH-B and SMMA/LDH-B samples were found to be transparent and were further examined for deduction of their structure (Fig. 5 and thermal properties. FTIR measurements showed that

  11. Photocatalytic water oxidation with iron oxide hydroxide (rust) nanoparticles

    Science.gov (United States)

    Shelton, Timothy L.; Bensema, Bronwyn L.; Brune, Nicholas K.; Wong, Christopher; Yeh, Max; Osterloh, Frank E.

    2017-01-01

    Hematite has attracted considerable interest as a photoanode material for water oxidation under visible illumination. Here, we explore the limits of photocatalytic water oxidation activity with iron (III) oxide hydroxide nanocrystals and NaIO4 as a sacrificial electron acceptor (E=1.63 V NHE at pH=0.5). The sol was prepared by hydrolysis of FeCl3 in boiling 0.002-M HCl solution and confirmed to mainly consist of ß-FeO(OH) (akaganéite) particles with 5 to 15 nm diameter. From a 0.01 M aqueous NaIO4 solution, the sol evolves between 4.5 and 35.2 μmol O2 h-1, depending on pH, light intensity (>400 nm, 290 to 700 mW cm-2), ß-FeO(OH), and NaIO4 concentration. The activity increases with pH, and depends linearly on light intensity and photocatalyst amount, and it varies with sacrificial electron donor concentration. Under optimized conditions, the apparent quantum efficiency is 0.19% (at 400 nm and 460 mW cm-2), and the turnover number is 2.58 based on total ß-FeO(OH). Overall, the efficiency of the ß-FeO(OH)/NaIO4 photocatalytic system is limited by electron hole recombination and by particle aggregation over longer irradiation times (24 h). Lastly, surface photovoltage measurements on ß-FeO(OH) films on fluorine doped tin oxide substrate confirm a 2.15 eV effective band gap for the material.

  12. Crystal growth of bismuth(V) oxides from hydroxide fluxes

    Science.gov (United States)

    Bharathy, M.; Khalsa, Hargobind S.; Smith, Mark D.; zur Loye, H.-C.

    2009-02-01

    The first example of a 2 H-perovskite related A3A'BiO 6 oxide, (Sr 2.59Ba 0.41)NaBiO 6, with two different divalent cations on the A site, was synthesized in a reactive, mixed strontium-, barium-, sodium-hydroxide flux. (Sr 2.59Ba 0.41)NaBiO 6 crystallizes in the space group R3¯c, with a = 9.9839(2) Å and c = 11.8008(4) Å. Crystals of isostructural oxides, Sr 3NaBiO 6 and Sr 3LiBiO 6, were also obtained from reactive Sr(OH) 2, NaOH and LiOH fluxes. Sr 3NaBiO 6 and Sr 3LiBiO 6 crystallize in the space group R3¯c with a = 9.9193(2) Å, c = 11.7473(5) Å and a = 9.9293(2) Å, c = 11.4188(5) Å, respectively. In addition, we report the crystal growth of a strontium bismuth oxyhydroxide, Sr 4(BiO 6)(OH), isolated from a reactive Sr(OH) 2 flux contained in sealed silver tubes. Sr 4(BiO 6)(OH) crystallizes in the monoclinic space group, P2 1 with a = 6.9429(8) Å, b = 6.1286(7) Å, c = 9.2746(10) Å, and β = 102.176(2)°. The structure consists of layers of connected SrO x polyhedra, with isolated BiO 6 octahedra located in every second Sr-O layer.

  13. The Effect of Ultrafine Magnesium Hydroxide on the Tensile Properties and Flame Retardancy of Wood Plastic Composites

    Directory of Open Access Journals (Sweden)

    Zhiping Wu

    2014-01-01

    Full Text Available The effect of ultrafine magnesium hydroxide (UMH and ordinary magnesium hydroxide (OMH on the tensile properties and flame retardancy of wood plastic composites (WPC were investigated by tensile test, oxygen index tester, cone calorimeter test, and thermogravimetric analysis. The results showed that ultrafine magnesium hydroxide possesses strengthening and toughening effect of WPC. Scanning electron micrograph (SEM of fracture section of samples provided the positive evidence that the tensile properties of UMH/WPC are superior to that of WPC and OMH/WPC. The limited oxygen index (LOI and cone calorimeter test illustrated that ultrafine magnesium hydroxide has stronger flame retardancy and smoke suppression effect of WPC compared to that of ordinary magnesium hydroxide. The results of thermogravimetric analysis implied that ultrafine magnesium hydroxide can improve the char structure which plays an important role in reducing the degradation speed of the inner matrix during combustion process and increases the char residue at high temperature.

  14. Effect of Operating Parameters and Chemical Additives on Crystal Habit and Specific Cake Resistance of Zinc Hydroxide Precipitates

    Energy Technology Data Exchange (ETDEWEB)

    Alwin, Jennifer Louise [New Mexico State Univ., Las Cruces, NM (United States)

    1999-08-01

    The effect of process parameters and chemical additives on the specific cake resistance of zinc hydroxide precipitates was investigated. The ability of a slurry to be filtered is dependent upon the particle habit of the solid and the particle habit is influenced by certain process variables. The process variables studied include neutralization temperature, agitation type, and alkalinity source used for neutralization. Several commercially available chemical additives advertised to aid in solid/liquid separation were also examined in conjunction with hydroxide precipitation. A statistical analysis revealed that the neutralization temperature and the source of alkalinity were statistically significant in influencing the specific cake resistance of zinc hydroxide precipitates in this study. The type of agitation did not significantly effect the specific cake resistance of zinc hydroxide precipitates. The use of chemical additives in conjunction with hydroxide precipitation had a favorable effect on the filterability. The morphology of the hydroxide precipitates was analyzed using scanning electron microscopy.

  15. The Effect of Ultrafine Magnesium Hydroxide on the Tensile Properties and Flame Retardancy of Wood Plastic Composites

    OpenAIRE

    Wu, Zhiping; Hu, Na; Wu, Yiqiang; Wu, Shuyun; Qin, Zu

    2014-01-01

    The effect of ultrafine magnesium hydroxide (UMH) and ordinary magnesium hydroxide (OMH) on the tensile properties and flame retardancy of wood plastic composites (WPC) were investigated by tensile test, oxygen index tester, cone calorimeter test, and thermogravimetric analysis. The results showed that ultrafine magnesium hydroxide possesses strengthening and toughening effect of WPC. Scanning electron micrograph (SEM) of fracture section of samples provided the positive evidence that the ten...

  16. Analysis of pH and release of calcium of association between melaleuca alternifolia oil and calcium hydroxide

    National Research Council Canada - National Science Library

    Maiara GIONGO; Rogério Aparecido Minini dos SANTOS; Sandra Mara MACIEL; Marina de Lourdes Calvo FRACASSO; Fausto Rodrigo VICTORINO

    2017-01-01

    .... Calcium hydroxide is used for this because of its excellent properties. Melaleuca alternifolia oil has shown medicinal importance by demonstrating antifungal and bactericidal action against proven human pathogens...

  17. Effect of calcium hydroxide pastes and vehicles on root canal dentin microhardness

    Directory of Open Access Journals (Sweden)

    María G Pacios

    2014-01-01

    Full Text Available Background: Calcium hydroxide pastes used in the endodontic therapy may produce changes in the physical properties of the dentin. Objective: The purpose of this study was to evaluate the effect of calcium hydroxide pastes and their vehicles on microhardness of root canal dentin. Materials and Methods: Sixty maxillary anterior teeth were used. The crowns of the teeth were removed at the cemento-enamel junction. Canals were instrumented, horizontally sectioned into 2 segments, embedded in acrylic resin, and polished. A total of 120 specimens were randomly divided into 12 groups. Specimens stayed in contact with the vehicles or the pastes prepared with the calcium hydroxide powder and the same vehicles. The vehicles are: Distilled water, chlorhexidine, carticaine in the anesthetic solution, propylene glycol, monochlorophenol and monochlorophenol - propylene glycol. The references Vickers microhardness were obtained prior the application of the medicaments. Samples were then exposed to the medicaments for 3, 7, and 14 days, and microhardness measured again. The results were statistically analyzed by one-way ANOVA, Tukey test, and regression. Results: All vehicles and pastes, except distilled water, significantly decreased the microhardness of the root dentin; however, calcium hydroxide + camphorated monochlorophenol - propylene glycol and camphorated monochlorophenol - propylene glycol showed the highest decrease. Conclusion: Vehicles contribute to calcium hydroxide reduction of root canal dentin microhardness as constituent of endodontic pastes.

  18. Efficacy of three methods for inserting calcium hydroxide-based paste in root canals.

    Science.gov (United States)

    Galvão, Thales; Camargo, Bernardo; Armada, Luciana; Alves, Flávio

    2017-06-01

    To compare the quality of calcium hydroxide paste fillings performed by three different techniques. Sixty extracted maxillary central incisors, with previous root canal treatment, were decoronated and the gutta-percha was completely removed from the root canals. Subsequently, the canals were filled with a calcium hydroxide-based paste composed of calcium hydroxide, bismuth carbonate, and glycerin. The study samples were divided into the following three groups on the basis of three insertion techniques (n = 20, each): conventional technique using a hand instrument (MAN), rotary Lentulo spiral (LEN) technique, and a combined technique combining conventional hand files with sonic activation through the EndoActivator device (EA). The quality of fillings was evaluated radiographically by two examiners on the basis of the amount of voids and the apical limit. The canals filled with LEN or MAN had less void volume compared to the EA technique ( P >0.01), with no significant differences between them. Considering the apical limits, the three tested techniques showed comparable results ( P >0.05). A combined approach utilizing hand files with sonic activation showed no enhancements over the LEN or MAN techniques on the quality of intracanal placement of calcium hydroxide paste. Key words: Calcium hydroxide placement, EndoActivator, Lentulo spirals, intracanal medication, root canal treatment.

  19. Relationship between sealing ability of Activ GP and Gutta Flow and methods of calcium hydroxide removal.

    Science.gov (United States)

    Nikhil, Vineeta; Singh, Vijay; Singh, Simranjeet

    2012-01-01

    To evaluate the effect of method of calcium hydroxide intracanal dressing removal, on sealing ability of Gutta Flow and Activ GP. Seventy extracted mandibular premolars were sectioned at CEJ and canals were prepared with profile 4% rotary file till #40. Canals were filled with calcium hydroxide, coronally sealed with Cavit G and stored at 37°C. After 7 days, samples were divided on the basis of calcium hydroxide removal method (Master apical file, Navi Tip FX, and F File) and obturating material (Activ GP and Gutta Flow). Three coats of nail polish were applied except 2 mm around apical foramen and samples were immersed in India ink dye, sectioned, and observed under stereomicroscope for microleakage. The results were statistically analyzed with one way ANOVA-F with Tukey HSD test with the null hypothesis set as 5%. The seal of the canal system was adversely impacted by residual calcium hydroxide when Activ GP and Gutta Flow were used as obturating material and the sealing ability of Activ GP and Gutta Flow was better when MAF was used for removal of calcium hydroxide than F file or Navi tip FX.

  20. Nickel hydroxides and related materials: a review of their structures, synthesis and properties

    Science.gov (United States)

    Hall, David S.; Lockwood, David J.; Bock, Christina; MacDougall, Barry R.

    2015-01-01

    This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol–gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of ‘unknown’ nickel hydroxide-based samples. PMID:25663812

  1. Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

    Directory of Open Access Journals (Sweden)

    Hirokazu Nakayama

    2014-07-01

    Full Text Available The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

  2. Self-diffusion coefficients of the trivalent f-element ion series in dilute and moderately dilute aqueous solutions: A comparative study between europium, gadolinium, terbium and berkelium

    Science.gov (United States)

    Rafik, Besbes; Noureddine, Ouerfelli; Abderabbou, Abdelmanef; Habib, Latrous

    2010-03-01

    We have continued the studies on the trivalent ions of the 4f and 5f elements. In this paper, we compare the transport properties (self-diffusion coefficient) of the trivalent aquo ions over two ranges of concentrations (0 — 2×10-3M) and (2×10-3 — 1.5M). Self-diffusion coefficients, D, of the trivalent f-element aquo ion series have been determined in aqueous background electrolytes of Gd(NO3)3 and Nd(ClO4)3, at pH=2.5 (HNO3, HClO4) and at 25°C using the open-end capillary method (O.E.C.M.). This method measures the transportation time of ions across a fixed distance. In this paper, we complete a measurement of self-diffusion coefficient for terbium. We optimized the pH to avoid hydrolysis, ion-pairing and complexation of the trivalent 4f and 5f ions. The variation of D versus √C is not linear for dilute solutions (0 — 2×10-3M) and quasi-linear in moderate concentrations (C<=1.5 M). Similar behavior was observed for Tb, as compared with those for Bk, Eu and Gd. We complete the comparison variation of D/D° versus √C for all studied 4f and 5f elements from concentration 0 to 1.5M and we obtained the same variation with √C for all studied elements. All 4f and 5f elements studied follow the Nernst-Hartley expression.

  3. Terbium-based time-gated Förster resonance energy transfer imaging for evaluating protein-protein interactions on cell membranes.

    Science.gov (United States)

    Lindén, Stina; Singh, Manish Kumar; Wegner, K David; Regairaz, Marie; Dautry, François; Treussart, François; Hildebrandt, Niko

    2015-03-21

    Fluorescence imaging of cells and subcellular compartments is an essential tool to investigate biological processes and to evaluate the development and progression of diseases. In particular, protein-protein interactions can be monitored by Förster resonance energy transfer (FRET) between two proximal fluorophores that are attached to specific recognition biomolecules such as antibodies. We investigated the membrane expression of E- and N-cadherins in three different cell lines used as model systems to study epithelial to mesenchymal transition (EMT) and a possible detection of circulating tumour cells (CTCs). EMT is a key process in cancer metastasis, during which epithelial markers (such as E-cadherin) are down-regulated in the primary tumour whereas mesenchymal markers (such as N-cadherin) are up-regulated, leading to enhanced cell motility, intravasation, and appearance of CTCs. Various FRET donor-acceptor pairs and protein recognition strategies were utilized, in which Lumi4-Tb terbium complexes (Tb) and different organic dyes were conjugated to several distinct E- and N-cadherin-specific antibodies. Pulsed excitation of Tb at low repetition rates (100 Hz) and time-gated (TG) imaging of both the Tb-donor and the dye-acceptor photoluminescence (PL) allowed efficient detection of the EMT markers as well as FRET in the case of sufficient donor-acceptor proximity. Efficient FRET was observed only between two E-cadherin-specific antibodies and further experiments indicated that these antibodies recognized the same E-cadherin molecule, suggesting a limited accessibility of cadherins when they are clustered at adherens junctions. The investigated Tb-to-dye FRET systems provided reduced photobleaching compared to the AlexaFluor 488-568 donor-acceptor pair. Our results demonstrate the applicability and advantages of Tb-based TG FRET for efficient and stable imaging of antibody-antibody interactions on different cell lines. They also reveal the limitations of

  4. A broad G protein-coupled receptor internalization assay that combines SNAP-tag labeling, diffusion-enhanced resonance energy transfer, and a highly emissive terbium cryptate acceptor

    Directory of Open Access Journals (Sweden)

    Angélique eLEVOYE

    2015-11-01

    Full Text Available Although G protein-coupled receptor (GPCR internalization has long been considered a major aspect of the desensitization process that tunes ligand responsiveness, internalization is also involved in receptor resensitization and signaling, as well as the ligand scavenging function of some atypical receptors. Internalization thus contributes to the diversity of GPCR-dependent signaling, and its dynamics and quantification in living cells has generated considerable interest. We developed a robust and sensitive assay to follow and quantify ligand-induced and constitutive GPCR internalization but also receptor recycling in living cells. This assay is based on diffusion-enhanced resonance energy transfer (DERET between cell surface GPCRs labeled with a luminescent terbium cryptate donor and a fluorescein acceptor present in the culture medium. GPCR internalization results in a quantifiable reduction of energy transfer. This method yields a high signal-to-noise ratio due to time-resolved measurements. For various GPCRs belonging to different classes, we demonstrated that constitutive and ligand-induced internalization could be monitored as a function of time and ligand concentration, thus allowing accurate quantitative determination of kinetics of receptor internalization but also half-maximal effective or inhibitory concentrations of compounds. In addition to its selectivity and sensitivity, we provided evidence that DERET-based internalization assay is particularly suitable for characterizing biased ligands. Furthermore, the determination of a Z’-factor value of 0.45 indicates the quality and suitability of DERET-based internalization assay for high-throughput screening (HTS of compounds that may modulate GPCRs internalization.

  5. Efficient uranium capture by polysulfide/layered double hydroxide composites.

    Science.gov (United States)

    Ma, Shulan; Huang, Lu; Ma, Lijiao; Shim, Yurina; Islam, Saiful M; Wang, Pengli; Zhao, Li-Dong; Wang, Shichao; Sun, Genban; Yang, Xiaojing; Kanatzidis, Mercouri G

    2015-03-18

    There is a need to develop highly selective and efficient materials for capturing uranium (normally as UO2(2+)) from nuclear waste and from seawater. We demonstrate the promising adsorption performance of S(x)-LDH composites (LDH is Mg/Al layered double hydroxide, [S(x)](2-) is polysulfide with x = 2, 4) for uranyl ions from a variety of aqueous solutions including seawater. We report high removal capacities (q(m) = 330 mg/g), large K(d)(U) values (10(4)-10(6) mL/g at 1-300 ppm U concentration), and high % removals (>95% at 1-100 ppm, or ∼80% for ppb level seawater) for UO2(2+) species. The S(x)-LDHs are exceptionally efficient for selectively and rapidly capturing UO2(2+) both at high (ppm) and trace (ppb) quantities from the U-containing water including seawater. The maximum adsorption coeffcient value K(d)(U) of 3.4 × 10(6) mL/g (using a V/m ratio of 1000 mL/g) observed is among the highest reported for U adsorbents. In the presence of very high concentrations of competitive ions such as Ca(2+)/Na(+), S(x)-LDH exhibits superior selectivity for UO2(2+), over previously reported sorbents. Under low U concentrations, (S4)(2-) coordinates to UO2(2+) forming anionic complexes retaining in the LDH gallery. At high U concentrations, (S4)(2-) binds to UO2(2+) to generate neutral UO2S4 salts outside the gallery, with NO3(-) entering the interlayer to form NO3-LDH. In the presence of high Cl(-) concentration, Cl(-) preferentially replaces [S4](2-) and intercalates into LDH. Detailed comparison of U removal efficiency of S(x)-LDH with various known sorbents is reported. The excellent uranium adsorption ability along with the environmentally safe, low-cost constituents points to the high potential of S(x)-LDH materials for selective uranium capture.

  6. High-temperature stabilization of polyolefines with hydroxides of alkali metals

    Energy Technology Data Exchange (ETDEWEB)

    Losev, Y.P.; Paushkin, Y.M. (V.I. Lenin Byelorussian State Univ., Universitetskii Gorodok, 220080 Minsk, Byelorussia (SU))

    1992-07-25

    This paper discusses polyolefines which are one of the main types of synthetic polymer materials. However, an important shortcoming is their low temperature resistance and heat stability, which reduce the processing efficiency and restrict their range of application. So far the study of high-temperature stabilization of polyolefines has been limited since solution of the problem involves some difficulties. In the case of polyolefine the use of stabilizers against thermal and light-oxidative degradation is not efficient since at high temperatures they easily decompose to form radical capable of initiating additional kinetic destruction chains. To date, few antioxidants and light stabilizers have been found that can partially inhibit thermal destruction of polyolefines. Hydroxides of alkali metals are shown to be high-temperature stabilizers of polyethylene. Potassium hydroxide is found to be most efficient. The reaction mechanism of alkali metal hydroxides as thermal stabilizers is considered.

  7. A role for calcium hydroxide and dolomite in water: acceleration of the reaction under ultraviolet light.

    Science.gov (United States)

    Nagase, Hiroyasu; Tsujino, Hidekazu; Kurihara, Daisuke; Saito, Hiroshi; Kawase, Masaya

    2014-04-01

    Organic environmental pollutants are now being detected with remarkably high frequency in the aquatic environment. Photodegradation by ultraviolet light is sometimes used as a method for removing organic chemicals from water; however, this method is relatively inefficient because of the low degradation rates involved, and more efficient methods are under development. Here we show that the removal of various organic pollutants can be assisted by calcined dolomite in aqueous solution under irradiation with ultraviolet light. It was possible to achieve substantial removal of bisphenol A, chlorophenols, alkylphenols, 1-naphthol and 17β-estradiol. The major component of dolomite responsible for the removal was calcium hydroxide. Our results demonstrate that the use of calcium hydroxide with ultraviolet light irradiation can be a very effective method of rapidly removing organic environmental pollutants from water. This is a new role for calcium hydroxide and dolomite in water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Bubble nucleation and migration in a lead–iron hydr(oxide) core–shell nanoparticle

    Science.gov (United States)

    Niu, Kaiyang; Frolov, Timofey; Xin, Huolin L.; Wang, Junling; Asta, Mark; Zheng, Haimei

    2015-01-01

    Iron hydroxide is found in a wide range of contexts ranging from biominerals to steel corrosion, and it can transform to anhydrous oxide via releasing O2 gas and H2O. However, it is not well understood how gases transport through a crystal lattice. Here, we present in situ observation of the nucleation and migration of gas bubbles in iron (hydr)oxide using transmission electron microscopy. We create Pb–FeOOH model core–shell nanoparticles in a liquid cell. Under electron irradiation, iron hydroxide transforms to iron oxide, during which bubbles are generated, and they migrate through the shell to the nanoparticle surface. Geometric phase analysis of the shell lattice shows an inhomogeneous stain field at the bubbles. Our modeling suggests that the elastic interaction between the core and the bubble provides a driving force for bubble migration. PMID:26438864

  9. The effects of hyaluronic acid, calcium hydroxide, and dentin adhesive on rat odontoblasts and fibroblasts.

    Science.gov (United States)

    Bogović, Ana; Nižetić, Jana; Galić, Nada; Zelježić, Davor; Micek, Vedran; Mladinić, Marin

    2011-06-01

    The aim of this study was to investigate the effects and efficiency of pulp capping preparations based on hyaluronic acid, calcium hydroxide, and dentin adhesive on the pulp tissue of Sprague-Dawley rats. The rats were killed and extracted teeth sectioned transversely through the pulp. The slices were placed in a RPMI 1640 cell culture medium supplemented with 10 % foetal calf serum. During 14 days of cultivation cultures were treated with preparations that contained hyaluronic acid (Gengigel Prof®), and calcium hydroxide (ApexCal®), or with dentin adhesive (Excite®). Cellularity and viability of fibroblasts and odontoblasts was analysed using a haemocytometer. Hyaluronic acid proved most efficient and the least toxic for direct pulp capping. Even though calcium hydroxide and dentin adhesive demonstrated a higher degree of cytotoxicity, their effects were still acceptable in terms of biocompatibility.

  10. Self-assembled zinc/copper hydroxide carbonates with tunable hierarchical nanostructure.

    Science.gov (United States)

    Zhou, Min; Hu, Ye; Ferrari, Mauro; Xie, Zhaohui

    2011-08-01

    Here, we report a synthetic, polymer-mediated method for the self-assembly of zinc/copper hydroxide carbonate superstructures including 3D hierarchical sunflower-like, urchin-like, alga-like, and rotiform-like zinc hydroxide carbonate (ZHC) microstructures, and hierarchical copper hydroxide carbonate (CHC) microspheres with radiating nanoplates and nanorods. As a capping agent, poly(vinylpyrrolidone) (PVP) was found to play an important role in directing the growth and self-assembly of such unique structures. The crystal structure of the products and the resulting hierarchical superstructure morphology, as controlled by the molecular weight and concentration of PVP, were systematically investigated. A possible growth mechanism for the formation of hierarchical superstructures with different morphologies is also proposed.

  11. Accidental periapical extrusion of non-setting calcium hydroxide: Unusual bone response and management

    Directory of Open Access Journals (Sweden)

    Divya S Sharma

    2014-01-01

    Full Text Available Premixed non-setting calcium hydroxide is frequently used as interim root canal dressing in endodontically involved permanent teeth and as obturating paste in deciduous teeth in pediatric dentistry. Wide apex in both cases makes it more prone for deliberate extrusion especially when applied with pressure delivery systems. Contrary to common belief the mix was not resorbed in two years with the complaint of insufficiency in mastication. Large mass of calcium hydroxide in bone delayed healing process even after its removal. The present case report intends to demonstrate unusual behavior of bone in response to oily non-setting preparation of calcium hydroxide. Therefore its application with pressure syringe should be reconsidered in pediatric dentistry.

  12. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Thimmasandra Narayan Ramesh

    2015-01-01

    Full Text Available Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spectroscopy. Different types of adsorption isotherm models were evaluated and it was found that Langmuir isotherm fits well at both pH values (6-7 and 12-13. Adsorption of indigo carmine onto magnesium hydroxide at pH 6-7/pH 12-13 follows pseudo-second order rate kinetics.

  13. Crystal structure of an eight-coordinate terbium(III ion chelated by N,N′-bis(2-hydroxybenzyl-N,N′-bis(pyridin-2-ylmethylethylenediamine (bbpen2− and nitrate

    Directory of Open Access Journals (Sweden)

    Thaiane Gregório

    2015-01-01

    Full Text Available The reaction of terbium(III nitrate pentahydrate in acetonitrile with N,N′-bis(2-hydroxybenzyl-N,N′-bis(pyridin-2-ylmethylethylenediamine (H2bbpen, previously deprotonated with triethylamine, produced the mononuclear compound [N,N′-bis(2-oxidobenzyl-κO-N,N′-bis(pyridin-2-ylmethyl-κNethylenediamine-κ2N,N′](nitrato-κ2O,O′terbium(III, [Tb(C28H28N4O2(NO3]. The molecule lies on a twofold rotation axis and the TbIII ion is eight-coordinate with a slightly distorted dodecahedral coordination geometry. In the symmetry-unique part of the molecule, the pyridine and benzene rings are both essentially planar and form a dihedral angle of 61.42 (7°. In the molecular structure, the N4O4 coordination environment is defined by the hexadentate bbpen ligand and the bidentate nitrate anion. In the crystal, a weak C—H...O hydrogen bond links molecules into a two-dimensional network parallel to (001.

  14. Antibiofilm efficacy of silver nanoparticles as a vehicle for calcium hydroxide medicament against Enterococcus faecalis.

    Science.gov (United States)

    Afkhami, Farzaneh; Pourhashemi, Seyyed Jalal; Sadegh, Mona; Salehi, Yasaman; Fard, Mohammad Javad Kharrazi

    2015-12-01

    The aim of the present study was to investigate antibacterial characteristic and Enterococcus faecalis (E. faecalis) biofilm suppression effect of different vehicles of calcium hydroxide as intracanal medicaments in short and long-term. Fifty-four human single-root teeth were contaminated with E. faecalis bacteria. The teeth were randomly divided into three experimental (n=16) and one control group (n=6). Each group was then exposed to various intracanal medicaments, namely calcium hydroxide paste (group 1), calcium hydroxide with chlorhexidine (group 2), calcium hydroxide with silver nanoparticles suspension (AgNPs) (group 3), and saline as the control group (group 4). Cultures were made from each group after one week and one month, and the number of colonies was counted. Moreover, a sample of each group was examined under electron microscope. Kruskal-Wallis test served for inter-group comparisons, and Mann-Whitney test served for comparison between the two incubation periods. All the intracanal medicaments resulted in significant decrease in number of colonies compared to control group in both incubation periods. After one week, the mixture of calcium hydroxide and AgNPs was the most effective medicament against E. faecalis bacteria (p.05). AgNPs was more effective on the E. faecalis biofilm than other tested vehicles in short-term medication. AgNPs seems to have a good potential to be used as an appropriate vehicle of calcium hydroxide in order to eliminate of E. faecalis biofilm from human dentine in short-term. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The Influence of Limestone And Calcium Hydroxide Addition in Asphalt Concrete Mixture

    Directory of Open Access Journals (Sweden)

    Gunaran Danny

    2016-06-01

    Full Text Available As time passes, flood often occurs in the area of Gunung Sahari, Jakarta Utara. The flood damages concrete asphalt mixture and it needs particular improvement. Therefore, the purpose of this research is to know the effects of the added combination of limestone and calcium hydroxide on concrete asphalt mixture as a filler resistant to flood. Concrete asphalt mixture that filled with the combination of limestone and calcium hydroxide is a mixture that is made with non-uniform aggregat gradations, filler and liquid asphalt mixed and solidified in a heat state. Limestone and calcium hydroxide mixture is used because both materials included in the most numerous sedimentary rock. Concrete asphalt mixture with the filler combination of limestone and calciumhydroxide is made with optimum asphalt 5.4%, one variation level of limestone (15%, and calcium hydroxide (15%, and three variation levels of fillers (5%, 7.5%, and 15% to get optimum asphalt levels and filler levels that are compatible with flood condition. Based on optimum asphalt 5.4% towards aggregate total weight and combined level of limestone and calcium hydroxide suitable for the conditions, 8.75 % towards fine aggregate weight. The characteristic value of limestone and calcium hydroxide mixture in maximum condition is VIM 4.55%, VMA 18.83%, stability 1031.26 kg and flow 4.93 mm, where the characteristic value meets the established specifications standard by Pekerjaan Umum Bina Marga. From the result, it is showed that the use of the mixture can decrease the value of stability and increase the value of flow, compared with asphalt and filler with normal levels.

  16. Aluminum phosphate shows more adjuvanticity than Aluminum hydroxide in recombinant hepatitis –B vaccine formulation

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Background: Although a number of investigation have been carried out to find alternative adjuvants to aluminum salts in vaccine formulations, they are still extensively used due to their good track record of safety, low cost and proper adjuvanticity with a variety of antigens. Adsorption of antigens onto aluminum compounds depends heavily on electrostatic forces between adjuvant and antigen. Commercial recombinant protein hepatitis B vaccines containing aluminum hydroxide as adjuvant is facing low induction of immunity in some sections of the vaccinated population. To follow the current global efforts in finding more potent hepatitis B vaccine formulation, adjuvanticity of aluminum phosphate has been compared to aluminum hydroxide. Materials and methods: The adjuvant properties of aluminum hydroxide and aluminum phosphate in a vaccine formulation containing a locally manufactured hepatitis B (HBs surface antigen was evaluated in Balb/C mice. The formulations were administered intra peritoneally (i.p. and the titers of antibody which was induced after 28 days were determined using ELISA technique. The geometric mean of antibody titer (GMT, seroconversion and seroprotection rates, ED50 and relative potency of different formulations were determined. Results: All the adjuvanicity markers obtained in aluminum phosphate formulation were significantly higher than aluminum hydroxide. The geometric mean of antibody titer of aluminum phosphate was approximately three folds more than aluminum hydroxide. Conclusion: Aluminum phosphate showed more adjuvanticity than aluminum hydroxide in hepatitis B vaccine. Therefore the use of aluminum phosphate as adjuvant in this vaccine may lead to higher immunity with longer duration of effects in vaccinated groups.

  17. Preparation of hydroxide ion conductive KOH–layered double hydroxide electrolytes for an all-solid-state iron–air secondary battery

    Directory of Open Access Journals (Sweden)

    Taku Tsuneishi

    2014-06-01

    Full Text Available Anion conductive solid electrolytes based on Mg–Al layered double hydroxide (LDH were prepared for application in an all-solid-state Fe–air battery. The ionic conductivity and the conducting ion species were evaluated from impedance and electromotive force measurements. The ion conductivity of LDH was markedly enhanced upon addition of KOH. The electromotive force in a water vapor concentration cell was similar to that of an anion-conducting polymer membrane. The KOH–LDH obtained was used as a hydroxide ion conductive electrolyte for all-solid-state Fe–air batteries. The cell performance of the Fe–air batteries was examined using a mixture of KOH–LDH and iron-oxide-supported carbon as the negative electrode.

  18. Determination of adsorbed protein concentration in aluminum hydroxide suspensions by near-infrared transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Jacobsen, Susanne

    2008-01-01

    Analysis of aluminum hydroxide based vaccines is difficult after antigen adsorption. Adsorbed protein is often assessed by measuring residual unadsorbed protein for quality control. A new method for the direct determination of adsorbed protein concentration in suspension using near-infrared (NIR...... in vaccine production as a method for quality control and quality assurance.......) transmittance spectroscopy is proposed here. A simple adsorption system using albumin from bovine serum (BSA) and aluminum hydroxide as a model system is employed. The results show that the NIR absorbance at 700-1300 nm is correlated to the adsorbed BSA concentration, measured by the ultraviolet (UV) method...

  19. Graphite Furnace Atomic Absorption Spectrometric Determination of Bismuth(III) after Coprecipitation with Hafnium Hydroxide

    OpenAIRE

    Ueda, Joichi; Takagi, Midori

    1990-01-01

    A method for the coprecipitation of bismuth(III) with hafnium hydroxide followed by a graphite-furnace atomic absorption spectrometric determination is described. Hafnium hydroxide coprecipitates quantitatively 0.05–3 μg of bismuth(III) from 50–400 cm3 of sample solution at pH 5.8–11.2. The presence of 2.5–50 mg of hafnium in 25 cm3 does not affect the atomic absorbance of bismuth(III). The calibration curve is linear for 0.05–3 μg of bismuth(III) in 25 cm3 and passes through the origin. Inte...

  20. Degradation of l-polylactide during melt processing with layered double hydroxides

    DEFF Research Database (Denmark)

    Gerds, Nathalie; Katiyar, Vimal; Koch, Christian Bender

    2012-01-01

    PLA was melt compounded in small-scale batches with two forms of laurate-modified magnesium–aluminum layered double hydroxide (Mg-Al-LDH-C12), the corresponding carbonate form (Mg-Al-LDH-CO3) and a series of other additives. Various methods were then adopted to characterize the resulting compounds...... in an effort to gain greater insights into PLA degradation during melt processing. PLA molecular weight reduction was found to vary according to the type of LDH additive. It is considered that the degree of particle dispersion and LDH exfoliation, and hence the accessibility of the hydroxide layer surfaces...

  1. Synthesis and characterization of laurate-intercalated Mg–Al layered double hydroxide prepared by coprecipitation

    DEFF Research Database (Denmark)

    Gerds, Nathalie Christiane; Katiyar, Vimal; Koch, Christian Bender

    2012-01-01

    Effective utilization of layered double hydroxides (LDH) for industrial applications requires the synthesis of pure and well-defined LDH phases. In the present study, dodecanoate (laurate) anions were intercalated into Mg–Al-layered double hydroxide (LDH-C12) by coprecipitation in the presence...... intercalated structure, but we here demonstrate it to be magnesium laurate (Mg-C12). The LDH-C12 compound showed high structural order with a basal spacing of 2.41nm. Fourier-transform IR-spectra confirmed the intercalation of the laurate anions in the interlayer. Transmission electron microscopy showed plate...

  2. Removal of Indigo Carmine Dye from Aqueous Solution Using Magnesium Hydroxide as an Adsorbent

    OpenAIRE

    Thimmasandra Narayan Ramesh; Vani Pavagada Sreenivasa

    2015-01-01

    Magnesium hydroxide is used as an adsorbent for the removal of indigo carmine dye from aqueous solution. We have investigated the effectiveness of removal of indigo carmine dye from aqueous solutions at pH 6-7 and 12-13 using magnesium hydroxide thereby varying the dose of the adsorbent, concentration of the dye, duration, and temperature. Structural transformations of adsorbent during the adsorption process at different pH values are monitored using powder X-ray diffraction and infrared spec...

  3. Electrocatalytic oxidation of urea by nanostructured nickel/cobalt hydroxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Vidotti, M. [Instituto de Quimica, Universidade de Sao Paulo, C.P. 26077, 05513-970 Sao Paulo, SP (Brazil); Silva, M.R. [Departamento de Quimica, Universidade Estadual de Londrina, C.P. 6001, 86051-580 Londrina, PR (Brazil); Salvador, R.P.; Torresi, S.I. Cordoba de [Instituto de Quimica, Universidade de Sao Paulo, C.P. 26077, 05513-970 Sao Paulo, SP (Brazil); Dall' Antonia, L.H. [Departamento de Quimica, Universidade Estadual de Londrina, C.P. 6001, 86051-580 Londrina, PR (Brazil)], E-mail: luizh@uel.br

    2008-04-20

    The present paper describes the catalytic oxidation of urea performed by nickel hydroxide and nickel/cobalt hydroxide modified electrodes by using both electrodeposited films and nanoparticles. The incorporation of Co foreign atoms leads to a slight increase in sensitivity besides the shift in redox process, avoiding the oxygen reaction. Nanostructured Ni{sub 80}Co{sub 20}(OH){sub 2} was synthesized by sonochemical route producing 5 nm diameter particles characterized by high-resolution transmission electron microscopy (HRTEM) being immobilized onto electrode by using the electrostatic Layer-by-layer technique, yielding attractive modified electrodes for sensor development.

  4. Ionic substitution of Mg2+ for Al3+ and Fe3+ with octahedral coordination in hydroxides facilitate precipitation of layered double hydroxides

    Science.gov (United States)

    Paikaray, Susanta; Essilfie-Dughan, Joseph; Hendry, M. Jim

    2018-01-01

    Precipitation of hydrotalcite-like layered double hydroxides (HT-LDHs) from CO32--SO42--rich acidic and alkaline aqueous media through ionic substitution of Mg2+ for Al3+ + Fe3+ and vice versa was investigated under ambient conditions. Diffractogram, spectroscopic, microprobe, microscopic, and synchrotron techniques were used to examine the mechanisms involved. The cations facilitated rapid precipitation of HT-LDH in alkaline conditions (pH ≥ 8.2) with SO42- and CO32- as the counter charge balancing interlayer anions, while initial formation of Fe3+- and Al3+-hydroxides in acidic conditions (pH ≥ 2.4) with subsequent transformation to MgAlFe-type HT-LDH (pH ≥ 8.2) occurred through substitution of Mg2+ for Al3+ and Fe3+. Substitution of Al3+ and Fe3+ in Mg2+-hydroxides did not yield HT-LDH, while the reverse, i.e., Mg2+ substitution in Al3+ and Fe3+-hydroxides, produced initial poorly ordered amorphous HT-LDH that gained better crystallinity and crystallite size upon neutralization. Linear combination fit analyses of XANES data suggest schwertmannite constituted the predominant Fe-phase until pH ∼3.7 followed by ferrihydrite and eventually HT-LDH after pH ≥ 10; basaluminite and epsomite constituted the predominant Al and Mg phases until pH ∼4.5, after which HT-LDH with minor Al(OH)3 and HT-LDH with brucite, respectively, predominated. The study highlights that Mg2+ substitution in Al- and Fe-precipitates is the governing mechanism for HT-LDH precipitation in oxic environments through neutralization of acidic cationic aqueous residues.

  5. Antimycobacterial, antimicrobial, and biocompatibility properties of para-aminosalicylic acid with zinc layered hydroxide and Zn/Al layered double hydroxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Saifullah B

    2014-07-01

    Full Text Available Bullo Saifullah,1 Mohamed E El Zowalaty,2,3 Palanisamy Arulselvan,2 Sharida Fakurazi,2,4 Thomas J Webster,5,6 Benjamin M Geilich,5 Mohd Zobir Hussein1 1Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 2Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 3Department of Environmental Health, Faculty of Public Health and Tropical Medicine, Jazan University, Jazan, Saudi Arabia; 4Department of Human Anatomy, Faculty of Medicine and Health Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 5Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USA; 6Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH, against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis.  Keywords: Zn/Al-layered double hydroxides, zinc layered hydroxides, tuberculosis, para

  6. Permanence and diffusion of borax-copper hydroxide remedial preservative applied to unseasoned pine posts : 10 year update

    Science.gov (United States)

    Douglas Crawford; Stan Lebow; Mike West; Bill Abbott

    2005-01-01

    In 1993, unseasoned pine posts were treated with groundline remedial treatment containing 3.1% copper hydroxide and 40% sodium tetraborate decahydrate (borax). The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, and 10 years, sections were taken from two posts to determine retention of borax and copper hydroxide below ground to 36...

  7. A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: Aqueous hydration of nitriles to amides

    Science.gov (United States)

    One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this...

  8. Utilization of Magnesium Hydroxide Produced by Magnesia Hydration as Fire Retardant for Nylon 6-6,6

    Directory of Open Access Journals (Sweden)

    Rocha Sônia D.F.

    2001-01-01

    Full Text Available The present work investigates the use of magnesium hydroxide, produced by magnesia hydration, as a fire retardant in polymers. The hydration was carried out in an autoclave, at temperature of 130°C for 1 hour, and the product was further submitted to cominution in a jet mill. The solids were characterized with regard to their chemical composition, particle size distribution, surface area and morphology. The performance evaluation of the hydroxide as a flame retardant for a copolymer of nylon 6-6,6 was carried out according to the UL94 specifications for vertical burning tests. V-0 flammability rating at 1.6 mm (60% magnesium hydroxide-filled nylon composite and at 3.2 mm (40% magnesium hydroxide filled nylon composite were achieved. Mechanical properties were maintained at the desired values. These results indicate that the hydroxide obtained from magnesia hydration can be successfully employed as a fire retardant for nylon 6-6,6.

  9. Effects of adhesions of amorphous Fe and Al hydroxides on surface charge and adsorption of K(+) and Cd(2+) on rice roots.

    Science.gov (United States)

    Liu, Zhao-Dong; Wang, Hai-Cui; Zhou, Qin; Xu, Ren-Kou

    2017-11-01

    Iron (Fe) and aluminum (Al) hydroxides in variable charge soils attached to rice roots may affect surface-charge properties and subsequently the adsorption and uptake of nutrients and toxic metals by the roots. Adhesion of amorphous Fe and Al hydroxides onto rice roots and their effects on zeta potential of roots and adsorption of potassium (K(+)) and cadmium (Cd(2+)) by roots were investigated. Rice roots adsorbed more Al hydroxide than Fe hydroxide because of the greater positive charge on Al hydroxide. Adhesion of Fe and Al hydroxides decreased the negative charge on rice roots, and a greater effect of the Al hydroxide. Consequently, adhesion of Fe and Al hydroxides reduced the K(+) and Cd(2+) adsorption by rice roots. The results of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and desorption of K(+) and Cd(2+) from rice roots indicated that physical masking by Fe and Al hydroxides and diffuse-layer overlapping between the positively-charged hydroxides and negatively-charged roots were responsible for the reduction of negative charge on roots induced by adhesion of the hydroxides. Therefore, the interaction between Fe and Al hydroxides and rice roots reduced negative charge on roots and thus inhibited their adsorption of nutrient and toxic cations. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. An Aluminum Magnesium Hydroxide Stearate-based Skin Barrier Protection Cream Used for the Management of Eczematous Dermatitis: A Summary of Completed Studies

    OpenAIRE

    Del Rosso, James Q.; Bhambri, Sanjay; Michaels, Brent

    2008-01-01

    Eczematous dermatoses can often be very difficult to treat. An aluminum magnesium hydroxide stearate-based cream has recently become available for clinical use. Aluminum magnesium hydroxide stearate-based cream provides an alternative option in treating these dermatoses while providing barrier protection against external allergens and irritants. This article reviews various studies evaluating aluminum magnesium hydroxide stearate-based cream.

  11. Effect of supplementation with barley and calcium hydroxide on intake of Mediterranean shrubs

    Directory of Open Access Journals (Sweden)

    Dragan Skobic

    2011-04-01

    Full Text Available Maquis plant communities are one of the most varied vegetation types in the Mediterranean region and an important habitat for wild and domestic herbivores. Although the majority of these shrubs are nutritious, the secondary compounds are main impediments that reduce their forage value. In five experiments we determined the effect of supplementing goats with calcium hydroxide plus barley, and barley alone on intake of five dominant shrubs (Quercus ilex, Erica multiflora, Arbutus unedo, Viburnum tinus and Pistacia lentiscus of the Mediterranean maquis community. The combination of calcium hydroxide plus barley and barley alone increased utilization of all five investigated Mediterranean shrubs; therewith that intake of Arbutus unedo and Viburnum tinus was not statistically significant. Supplemented goats with calcium hydroxide plus barley or barley alone could be effective in controlling secondary compounds-rich Mediterranean shrubs where their abundance threatens biodiversity. This control can be facilitated by browsing dominant Mediterranean shrubs, which has been shown to be effective in managing Mediterranean maquis density. Calcium hydroxide and barley (energy enhance use of secondary compounds-containing plants, which may increase production of alternate forages and create a more diverse mix of plant species in the Mediterranean maquis plant community.

  12. Acetyl salicylic acid–ZnAl layered double hydroxide functional nanohybrid for skin care application

    CSIR Research Space (South Africa)

    Mosangi, Damodar

    2016-10-01

    Full Text Available In this study, a pharmaceutically active ingredient, acetyl salicylic acid (ASA), was intercalated into ZnAl layered double hydroxide (LDH). The LDH–ASA nanohybrid material was characterized by XRD, FTIR, SEM, ICP-MS, TEM and TGA. Successful...

  13. Device to generate high purity hydroxide solution in-line for ion chromatography.

    Science.gov (United States)

    Masunaga, Hiroto; Higo, Yuji; Ishii, Mizuo; Maruyama, Noboru; Yamazaki, Shigeo

    2016-05-06

    Herein, we report a new device that generates a high-purity hydroxide solution in line. The device's container has three compartments that are isolated from each other by two cation exchange (CE) membranes. In each end of the container, an electrode is installed. The three compartments are filled with ion exchange resins. A bipolar boundary is a composite boundary comprising anion- and cation-exchangers. This device has two bipolar boundaries, which are used to separate the location of hydroxide solution generation from the location where water is electrolyzed. Therefore, it can produce high-purity hydroxide solutions that are free from gases and anionic impurities. The hydroxide solution is generated on the basis of an electrokinetic phenomenon at the surfaces of ion-exchange resins and membranes in an electric field; NaOH concentration can be controlled at rates from 0.01 to 100mM per 1mL/min by adjusting the electrical current (0-200mA) applied to the device. As the generated solution is used as an eluent for a suppressed anion chromatography, the electrical conductivity of the effluent from the suppressor is as low as that of ultra-pure water. Thus, the noise of the base-line electrical conductivity is improved, and so the detection limit of anions on the sub-ng/mL order can be achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Inhibition of pH fronts in corrosion cells due to the formation of cerium hydroxide

    NARCIS (Netherlands)

    Soestbergen, M. van; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G.

    2013-01-01

    The effect of cerium-based corrosion inhibitors on the pH front between the alkaline cathode and acidic anode in corrosion cells has been studied. The cerium component of these inhibitors can affect the pH front since it precipitates in an alkaline environment as cerium hydroxide, which is important

  15. Comparison of Calcium Hydroxide and Bioactive Glass after Direct Pulp Capping in Primary Teeth

    Directory of Open Access Journals (Sweden)

    R. Haghgoo

    2007-12-01

    Full Text Available Objective: Bioactive glass is often used as a filler material for repair of dental bone defects.In different studies osteogenic potential of this material was proved, but its dentinogenesisproperty is in doubt. The purpose of this study was to evaluate the histological pulp responses of Calcium hydroxide and Bioactive glass placed directly on exposed pulp tissues.Materials and Methods: Twenty teeth to be extracted due to orthodontic reasons were selected. These teeth were divided into two groups and treated with direct pulp capping.Calcium hydroxide was used for 10 teeth and Bioactive glass for 10 teeth. After 60 daysthe teeth were extracted and prepared for histological evaluation. Finally the data was analyzed with exact Fisher test.Results: All teeth treated with Calcium hydroxide showed inflammation. Internal resorption was seen in six teeth, abscess in five teeth and dentinal bridge in two teeth. Inflammationwas seen in three Bioactive glass samples and dentinal bridge in seven teeth, but internal resorption and abscess were not seen.Conclusion: Bioactive glass appears to be superior to Calcium hydroxide as a pulp capping agent in primary teeth.

  16. The conditions for electrodeposition of insoluble hydroxides at a cathode surface

    DEFF Research Database (Denmark)

    Hansen, P.Gregers

    1959-01-01

    The pH values obtained in the vicinity of a cathode surface where hydrogen evolution takes place are discussed using the concept of a diffusion layer. It is shown that a given current density I determines a hydrogen ion concentration Cmax in the solution, above which no hydroxide deposition at th...

  17. Aerobic Oxidation of 5-(Hydroxymethyl)furfural in Ionic Liquids with Solid Ruthenium Hydroxide Catalysts

    DEFF Research Database (Denmark)

    Ståhlberg, Tim Johannes Bjarki; Eyjolfsdottir, Ester; Gorbanev, Yury

    2012-01-01

    The aerobic oxidation of 5-(hydroxymethyl)furfural was investigated over solid ruthenium hydroxide catalysts in ionic liquids at elevated temperatures and pressures. Several different catalyst supports were tested in combination with various ionic liquids. The best result was obtained in [EMIm...

  18. Preparation and Characterization of Natural Rubber/Layered Double Hydroxide Nanocomposites

    Science.gov (United States)

    Abdullah, M. A. A.; Ahmad, M. B.; Yunus, W. M. Z. Wan; Rahman, M. Z. Ab.; Hussein, M. Z.; Dahalan, K. Z. M.

    2007-05-01

    Nanocomposites of organo Zn-Al layered double hydroxide (LDH) with natural rubber (SMR CV60) were successfully synthesized and characterized. To prepare the nanocomposites, a hydrophilic Zn-Al layer double hydroxide (ZnAl LDH -NO3-) was first converted into the organophilic form by using dodecylsulphate ion (DS) as a guest in Zn-Al layer double hydroxide (ZnAl LDH-DS). Intercalation of dodecylsulphate anion into the interlayer of LDH increased the surface area and the porosity of LDH. Nanocomposites of NR / ZnAl LDH-DS was then prepared by melt intercalation method using Haake internal mixer. The resulting compounds were then vulcanizated using the conventional method. X-Ray diffractogram the organophilic ZnAl-DS LDH shows the basal spacing of the ZnAl-LDH expands from 0.89 nm with nitrate as the intergallery anions to 2.53 nm due to the accommodation of DS surfactant anions. After the compounding with the natural rubber, the basal spacing of ZnAl LDH-DS in the composites is increased to 3.90 and 3.66 nm when the Zn-Al-LDH-DS contents are 1 phr and 15 phr respectively. TEM revealed the layered double hydroxide generally uniformly distributed in the rubber matrix. Further characterization indicates that the tensile strength of NR/ Zn-Al LDH-DS (nanocomposites) is higher than that of the NR/Zn-Al LDH-NO3- (macrocomposites).

  19. Synergy and Diffusion with a Borax-Copper Hydroxide Groundline Preservative: 20 Year Update

    Science.gov (United States)

    Stan Lebow; Bessie Woodward; Bill Abbott; Mike West

    2014-01-01

    A groundline remedial treatment containing 3.1% copper hydroxide (2% elemental copper) and 40% sodium tetraborate decahydrate (borax) was applied to unseasoned pine posts prior to placement in a test site in southern Mississippi. The soundness of the posts was periodically evaluated using a push test. After 3.5, 6.5, 10, 15 and 20 years, sections were taken from two...

  20. Clinical Survey of Successfulness of DPC with MTA and Calcium Hydroxide

    Directory of Open Access Journals (Sweden)

    E.Yasini

    2005-02-01

    Full Text Available Statement of Problem: The pulp may be exposed during remove of caries or by traumatic and iatrogenicinjuries. The material used to DPC, must be biocompatible, scalable and prevent bacterial leakage.Furthermore, it is better to stimulate dentinogenesis. Calcium hydroxide is most usual material for DPC. But itcannot provide a suitablcbiologic seal. Mineral irioxide aggregate (MTA is also a suitable material for DPC.Purpose: The aim of this study was to compare the clinical success of DPC done with MTA or calciumhydroxide cement.Materials and Methods: In this study eighteen posterior teeth without previous spontaneous pain thatinvolved mechanicaly exposure was randomly selected and capped with MTA or calcium hydroxide. These teeth were evaluated by clinical vitality test and radiograph after 3 and 12 months, and patients werequestioned about irritative or spontancus pain in this period. Statistical analysis was carried out by Usher exacttest (a-0.05.Results: This study showed that in calcium hydroxid groud three had irreversible pulpitis and two teeth had symptom and signs of reversible pulpitis. While, In MTA group all cases were normaL and no clinical sign was evident.Conclusion: MTA exhibited better results than calcium hydroxide cement for the capping of the pulp in human

  1. Evaluation of 6 years use of sodium hydroxide solution to clear partially occluded central venous catheters

    NARCIS (Netherlands)

    Bader, Suzanne G.; Balke, Petra; Jonkers-Schuitema, Cora F.; Tas, Tirzah A. J.; Sauerwein, Hans P.

    2007-01-01

    BACKGROUND & AIMS: Central venous catheter occlusion is a frequently occurring complication during home parenteral nutrition (HPN). The aim of the study was to investigate the effectiveness of sodium hydroxide (NaOH) administration to clear an occluded central venous catheter especially in HPN.

  2. Effect of an oily calcium hydroxide suspension on early wound healing after nonsurgical periodontal therapy.

    NARCIS (Netherlands)

    Kasaj, A.; Willershausen, B.; Berakdar, M.; Tekyatan, H.; Sculean, A.

    2006-01-01

    The purpose of the present study was to evaluate clinically the effect of an oily calcium hydroxide suspension on early wound healing after nonsurgical periodontal therapy. A total of 19 patients with chronic periodontitis were enrolled in the study. Each subject had three sites in each of two

  3. Gold Nanoparticles on Layered Double Hydroxide Nanosheets and Its Electrocatalysis for Glucose Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hye Ran; Lee, Jong Hyeon [The Catholic University of Korea, Bucheon (Korea, Republic of); Cho, Se Hee; Ji, Hong Geun [H and A PharmaChem, Bucheon (Korea, Republic of)

    2016-03-15

    We developed a new way to form the well-defined nanocomposite of Au NPs and exfoliated LDH nanosheet by in situ chemical reduction with NaBH{sub 4}. The optical and structural studies indicate that the Au NPs are highly dispersed and immobilized on the surface of LDH nanosheets. The Au/LDH nanosheet exhibited an excellent electrocatalysis toward glucose oxidation reaction. The results strongly demonstrate that the nanoscopic natures and dense positive charges of LDH nanosheet effectively stabilized the Au NPs to maintain their inherent properties during the synthesis and the electrocatalysis. The use of the double hydroxide nanosheets as nanoscopic support materials for the transition-metal NPs will dramatically improve their functionalities in heterogeneous catalysis. Recently, two-dimensional nanosheet of exfoliated layered double hydroxide (LDH) has emerged as a new type of solid support to immobilize the diverse metal NPs because of the large metal hydroxide area, good biochemical stability, and highly charged positive potential of 1- to 2-nm thick LDH layers. LDHs consist of a continuous stack of positively charged metal hydroxide layers with counter anions and water molecules placed in interlayer spaces.

  4. Hydrothermal Synthesis and Characterization of 3R Polytypes of Mg-Al Layered Double Hydroxides

    NARCIS (Netherlands)

    Budhysutanto, W.N.

    2010-01-01

    Layered Double Hydroxides (LDH) is a unique group of clays that have an anionic exchange capability. This research explored the hydrothermal method as an alternative method to synthesize Mg-Al LDH. It is a simple and more environmentally friendly compared to the conventional method of

  5. Facile preparation of layered double hydroxide/MoS{sub 2}/poly(vinyl alcohol) composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Keqing, E-mail: zhoukq@cug.edu.cn [Faculty of Engineering, China University of Geosciences (Wuhan), 388 Lumo Road, Wuhan, Hubei, 430074 (China); Hu, Yixin [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Liu, Jiajia [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026 (China); Gui, Zhou, E-mail: zgui@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026 (China); Jiang, Saihua [School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road 381, Guangzhou, 510641 (China); Tang, Gang [School of Architecture and Civil Engineering, Anhui University of Technology, 59 Hudong Road, Ma' anshan, Anhui, 243002 (China)

    2016-08-01

    In present study, the layered double hydroxide/MoS{sub 2} hybrids are facilely synthesized by self-assembly of exfoliated MoS{sub 2} nanosheets and layered double hydroxide nanoplates via electrostatic interaction, with the aim of combining their physical and chemical functionalities to form a promising nanofiller for flame retardancy in polymer composites. The structure and morphology of the layered double hydroxide/MoS{sub 2} hybrids are probed by X-ray diffraction and transmission electron microscopy. Subsequently, the hybrids are incorporated into poly (vinyl alcohol) to serve as reinforcements. The flame retardant efficiency of MoS{sub 2} nanosheets in poly (vinyl alcohol) is significantly enhanced after the incorporation of layered double hydroxide nanoplates, which can be explained by the forming of a compact and uniform char during combustion. - Highlights: • The LDH/MoS{sub 2} hybrids were facilely synthesized by self-assembly method. • The flame retardant efficiency of LDH/MoS{sub 2} hybrids in PVA was significantly enhanced. • It is a promising strategy for improving the flame retardant efficiency of MoS{sub 2}.

  6. Porous layered double hydroxides synthesized using oxygen generated by decomposition of hydrogen peroxide

    NARCIS (Netherlands)

    Gonzalez Rodriguez, P.; de Ruiter, M.P.; Wijnands, Tom; ten Elshof, Johan E.

    2017-01-01

    Porous magnesium-aluminium layered double hydroxides (LDH) were prepared through intercalation and decomposition of hydrogen peroxide (H2O2). This process generates oxygen gas nano-bubbles that pierce holes in the layered structure of the material by local pressure build-up. The decomposition of the

  7. CHEMICAL DISSOLUTION OF NICKEL (II OXIDE AND HYDROXIDE IN AMINO ACID SOLUTIONS

    Directory of Open Access Journals (Sweden)

    S.V. Ivanov

    2005-02-01

    Full Text Available  Simulation experimenting has been used to analyze thermodynamics of chemical dissolution of nickel (II oxide and hydroxide in solutions containing various amino acids. Allowance for complexation, protonation and hydrolysis processes has been found to be a must for adequate description of chemical processes.

  8. Titration of Monoprotic Acids with Sodium Hydroxide Contaminated by Sodium Carbonate.

    Science.gov (United States)

    Michalowski, Tadeusz

    1988-01-01

    Discusses the effects of using carbon dioxide contaminated sodium hydroxide solution as a titrant for a solution of a weak monoprotic acid and the resulting distortion of the titration curve in comparison to one obtained when an uncontaminated titrant is used. (CW)

  9. Poly I-lactide-layered double hydroxide nanocomposites via in situ polymerization of I-lactide

    DEFF Research Database (Denmark)

    Katiyar, Vimal; Gerds, N.; Koch, C.B.

    2010-01-01

    The use of clay nanofillers offers a potential route to improved barrier properties in polylactide films. Magnesium–aluminium layered double hydroxides (LDHs) are interesting in this respect and we therefore explored synthesis of PLA-LDH nanocomposites by ring-opening polymerization. This method...

  10. Formation of nematic liquid crystals of sterically stabilized layered double hydroxide platelets

    NARCIS (Netherlands)

    Mourad, M.C.D.|info:eu-repo/dai/nl/304837563; Devid, E.J.; van Schooneveld, M.M.|info:eu-repo/dai/nl/315032863; Vonk, Ch.; Lekkerkerker, H.N.W.|info:eu-repo/dai/nl/159054885

    2008-01-01

    Colloidal platelets of hydrotalcite, a layered double hydroxide, have been prepared by coprecipitation at pH 11−12 of magnesium nitrate and aluminum nitrate at two different magnesium to aluminum ratios. Changing the temperature and ionic strength during hydrothermal treatment, the platelets were

  11. [Effect of combination pretreatment of polyethylene glycol solution and magnesium hydroxide for colonoscopy].

    Science.gov (United States)

    Shin, Eun Kyung; Park, Seun Ja; Kim, Kyu Jong; Moon, Won; Park, Moo In; Lim, Dong Han; Park, Eun Ho; Lee, Jee Suk

    2010-04-01

    This study was designed to compare the efficacy and patient tolerance between standard bowel preparation using 4 liters of polyethylene glycol (PEG) solution and 4 liters of PEG preceded by the osmotic laxative, magnesium hydroxide in constipation and non-constipation group. 173 outpatient colonoscopy, except for three patients who were not taking magnesium, were divided into constipation and non-constipation group. Then, the patients were randomly assigned to receive 4-liter of PEG solution or 4-liter of PEG plus magnesium hydroxide. The quality of bowel preparation was assessed using Ottawa scale, and satisfaction score was assessed using questionnaires. Solid stool, cecal intubation time, compliance, and side effects were assessed. Non-constipation group showed no significant differences between two groups. In constipation group, 4-liter PEG solution plus magnesium hydroxide induced the more effective colonic preparation (Ottawa scale 2.47+/-0.99 vs. 5.92+/-2.39, pmagnesium hydroxide and 4 liters of PEG solution might reduce solid stool in constipation group, but could not improve preparation quality.

  12. Hollow nickel-aluminium-manganese layered triple hydroxide nanospheres with tunable architecture for supercapacitor application

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekaran, Nivedhini Iswarya; Muthukumar, Harshiny; Sekar, Aiswarya Devi; Manickam, Matheswaran, E-mail: math.chem95@gmail.com

    2017-07-01

    Hollow triple layered Ni-Al-Mn hydroxide nanocomposite is a promising electrode material with high capacitance value. Moreover, the material provides a high energy density with good cycling stability. Here we demonstrate the facile method for preparation of hollow layered triple hydroxide material in a combination of Nickel, Aluminium and Manganese with high surface area and mesoporous nature. Owing to its high electrode area and fast electron-ion transfer nature, the hollow Ni-Al-Mn hydroxide exhibits the high capacitance of 1756 F/g at 4 A/g and retains its capacitance value upto 89.5% of initial values after 4000 cycles. Additionally, it provides a higher energy density of 239.0795 Wh/kg at a power density of 1980 W/kg. HLTH of Ni-Al-Mn nanocomposite provides a better capacitance effect. Finally, this material provides a general approach for designing supercapacitor with tunable nanostructure and enhanced supercapacitor behaviour has a large application in energy storage and conversion devices. - Highlights: • An approach to acquire a hollow Ni-Al-Mn layered triple hydroxide is presented. • HLTH shows a large surface area suitable for electrochemical performance. • Exhibits high energy density of 239.07 Wh/kg at a power density of 1980 W/kg. • Recorded specific capacitance of 1756 F/g at current density 4 A/g. • HLTH retains 89.5% of initial capacitance values after 4000 cycles.

  13. A novel guanidinium grafted poly(aryl ether sulfone) for high-performance hydroxide exchange membranes.

    Science.gov (United States)

    Zhang, Qiang; Li, Shenghai; Zhang, Suobo

    2010-10-28

    A novel poly(aryl ether sulfone) ionomer containing hexaalkylguanidinium groups was synthesized, and membranes formed from this polymer displayed large ionic clusters, high hydroxide conductivity, and excellent solubility in low boiling point water-soluble solvents such as ethanol and methanol.

  14. Pulp capping with adhesive resin-based composite vs. calcium hydroxide: a review.

    Science.gov (United States)

    Schuurs, A H; Gruythuysen, R J; Wesselink, P R

    2000-12-01

    The results of some short-term experiments suggest that direct capping of a vital pulp with the modern resin-based composite systems may be as effective as capping with calcium hydroxide. Total cavity etching with 10% phosphoric acid seems to be safe for the exposed pulp, but unless annulled by calcium hydroxide 35% phosphoric acid may be disastrous. For hemostasis and cleaning of the pulp wound both sodium hypochlorite and saline seem suitable, whereas the effectiveness of a 2% chlorhexidine solution is questionable. Although hard-setting calcium hydroxide cements may induce the formation of dentin bridges, they appear not to provide an effective long-term seal against bacterial factors. Within a few years, the majority of mechanically exposed and capped pulps show infection and necrosis due to microleakage of such capping materials and tunnel defects in the dentin bridges. It is unknown whether newer types of resin containing calcium-hydroxide-products will act as a permanent barrier. The cytotoxicity of the resin-based composites and the temperature rise during polymerisation may not be of concern, but microleakage, sensitisation and allergic reactions may pose problems. Based on available data, pulp capping with resin-based composites may be said to be promising, but more and long-term research is mandatory before the method can be recommended.

  15. Comparison of the Winograd method and chemical cauterization with 10% sodium hydroxide for treating ingrown toenails

    Directory of Open Access Journals (Sweden)

    Nebahat Demet Akpolat

    2016-09-01

    Full Text Available Background and Design: This study was performed to assess the therapeutic outcomes of the surgical method, described by Winograd and chemical cauterization with sodium hydroxide in patients with Heifetz stage 2 and 3 ingrown toenail (recurrence, complication, improvement and time to regain activity. Materials and Methods: One-hundred patients who presented to the outpatient clinics of orthopedics, general surgery and dermatology with the complaints of pain, redness and discharge in the toenail between January 2010 and January 2012 and who failed to respond to conservative treatment and were diagnosed with Heifetz stage 2 and 3 ingrown toenail. Fifty patients underwent chemical cauterization with sodium hydroxide while 50 underwent Winograd surgery. Results: The patients were followed up for a year at 2-month intervals. While no recurrence was observed in patients who received chemical cauterization, five patients who underwent Winograd surgery had recurrence (p=0.022. Three patients receiving Winograd surgery were found to have superficial wound side infection on postoperative follow-up (p=0.08. Patients, who underwent chemical cauterization with sodium hydroxide, were detected to improve and return to normal activity in a shorter period. Conclusion: Chemical cauterization of the germinal matrix with 10% sodium hydroxide is a convenient method with a low rate of complication and recurrence compared to the Winograd surgery in the treatment of ingrown toenails.

  16. Sorption of sodium hydroxide by type I collagen and bovine corneas.

    Science.gov (United States)

    Whikehart, D R; Edwards, W C; Pfister, R R

    1991-01-01

    There are no quantitative studies on the uptake of alkali into corneal tissues. To study this phenomenon, both type I collagen and bovine corneas were incubated in sodium hydroxide (NaOH) under varying conditions for periods up to 27.5 h. The sorption (absorption or adsorption) of the alkali to protein and tissue was measured as the quantity of NaOH no longer available for titration to neutrality with hydrochloric acid. Sorption was found to be dependent on the concentration of NaOH (0.01-1 N) but independent of the incubation temperature (4-35 degrees C). In whole cornea, sorption of 1 N NaOH began immediately and increased with time up to 6 h. After 6 h, sorption decreased, together with the observed degradation and solubilization of the tissue. Stripping of the corneal endothelium alone or of the endothelium and epithelium increased sorption in a similar manner when compared to whole corneas for periods up to 4 h. These observations are compatible with ionic and nonionic bonding of hydroxide ions to collagen (including that of the cornea) and the subsequent release of hydroxide ions during hydrolysis of the protein itself. Indirect evidence also suggests the inclusion of quantities of unbound hydroxide ions in hydrated gels of glycosaminoglycans. It is proposed that in a chemical burn of the cornea, alkali is both stored in the tissue (by sorption) and reacted with it (by hydrolysis), without any net consumption of alkali taking place.

  17. Ion Association versus Ion Interaction Models in Examining Electrolyte Solutions: Application to Calcium Hydroxide Solubility Equilibrium

    Science.gov (United States)

    Menéndez, M. Isabel; Borge, Javier

    2014-01-01

    The heterogeneous equilibrium of the solubility of calcium hydroxide in water is used to predict both its solubility product from solubility and solubility values from solubility product when inert salts, in any concentration, are present. Accepting the necessity of including activity coefficients to treat the saturated solution of calcium…

  18. Aging of trivalent metal hydroxide/oxide gels in divalent metal salt ...

    Indian Academy of Sciences (India)

    Unknown

    pH metric titrations, involving the slow addition of NaOH to a mixed metal (M2+ + M′3+) salt solution. Two pH plateaus were observed, the first corresponding to the precipita- tion of the trivalent hydroxide, 'M′(OH)3', followed by the second, which was attributed to LDH formation. By esta- blishing equilibrium after each ...

  19. Speciation of heavy metal ions as influenced by interactions with montmorillonite, Al hydroxide polymers and citrate

    NARCIS (Netherlands)

    Janssen, R.P.T.

    1995-01-01

    Clay minerals, metal-hydroxides and organic matter can bind metal ions; moreover they also interact with each other. These mutual interactions influence the metal binding to a significant extent. In this study, the speciation of the heavy metal ions Zn and Ph was investigated in model

  20. Iron oxide/hydroxide nanoparticles with negatively charged shells show increased uptake in Caco-2 cells.

    Science.gov (United States)

    Jahn, Markus R; Nawroth, Thomas; Fütterer, Sören; Wolfrum, Uwe; Kolb, Ute; Langguth, Peter

    2012-06-04

    The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and because ferrous iron, but not ferric iron, is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. Iron hydroxide nanoparticles with neutral and hydrophilic carbohydrate shells are alternatively used to ferrous salts. In these formulations gastrointestinal side effects are rare because hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by the solubilizing shell; nevertheless, iron bioavailability is even worse compared to ferrous salts. In this study the cell uptake of iron hydroxide and iron oxide nanoparticles (FeONP) with negatively charged shells of different chemical types and sizes was compared to the uptake of those with neutral hydrophilic shells, ferrous sulfate and ferric chloride. The nanoparticle uptake was measured in Caco-2 cells with the iron detecting ferrozine method and visualized by transmission electron microscopy. The toxicity was evaluated using the MTT assay. For nanoparticles with a negatively charged shell the iron uptake was about 40 times higher compared to those with neutral hydrophilic carbohydrate shell or ferric chloride and in the same range as ferrous sulfate. However, in contrast to ferrous sulfate, nanoparticles with negatively charged shells showed no toxicity. Two different uptake mechanisms were proposed: diffusion for hydroxide nanoparticles with neutral hydrophilic shell and adsorptive endocytosis for nanoparticles with negatively charged shells. It needs to be determined whether iron hydroxide nanoparticles with negatively charged shells also show improved bioavailability in iron-deficient patients compared to iron hydroxide nanoparticles with a neutral hydrophilic shell, which exist in the market today.

  1. Comparison Of Efficacy Of 10% Potassium Hydroxide Solution Versus Cryotherapy In Treatment Of Molluscum Contagiosum.

    Science.gov (United States)

    Qureshi, Asfandyar; Zeb, Mahwish; Jalal-Ud-Din, Mir; Sheikh, Zafar Iqbal; Alam, Muhammad Adeel; Anwar, Syed Abbas

    2016-01-01

    Different topical therapies are being used for treating molluscum contagiosum. Potassium hydroxide in varying solution strengths with irritant reaction on the skin can help in eliminating the infection. It is cheap, easily available, can be easily applied at home, with good safety profile and cost effectiveness. This study was conducted to compare the efficacy of 10% potassium hydroxide solution versus cryotherapy in treating molluscum contagiosum. This study was a Randomized control trial conducted in the Department of dermatology, Military hospital Rawalpindi. Study included 120 randomly selected patients with molluscum contagiosum divided equally into two groups. Group A were treated with 10% potassium hydroxide aqueous solution applied daily to the lesions twice daily for 6 weeks while Group B received weekly cryotherapy with liquid nitrogen. The status of lesions was documented weekly for 6 weeks. Of the 120 patients enrolled, 67 (55.8%) were male and 53 (44.2%) were female. Mean age of patients was 20.53(±8.17) years. At base line Molluscum contagiosum lesion ranged from minimum of 2 lesions to maximum of 26 lesions with a mean of 8.95 (SD ±4.45) lesions. Of 120 patients, complete clearance was observed in 98(81.6%) of patients, 48(80%) patients had lesion clearance in Group A and 50 (83.3%) patients had lesion clearance was observed in Group B. No statistical significance was observed in the lesion clearance between the two groups (p-0.63). The efficacy of 10% potassium hydroxide solution and cryotherapy is statistically same over 6 weeks of treatment. Thus less expensive, easily available and cosmetically more acceptable potassium hydroxide solution can be used instead of cryotherapy in treating molluscum contagiosum.

  2. Effect of calcium hydroxide on ph changes of the external medium after intracoronal bleaching.

    Science.gov (United States)

    Sa, Patricia Marra de; Jeronymo, Raffaela Di Iorio; Yui, Karen Cristina Kazue; Silva, Eduardo Galera da; Huhtala, Maria Filomena Rocha Lima; Torres, Carlos Rocha Gomes; Gomes, Ana Paula Martins

    2011-05-01

    This in vitro study evaluated the effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching. A total of 50 extracted human premolars were prepared and filled with gutta-percha and endodontic sealer. The teeth were randomly divided into five groups according to the bleaching agents employed: (a) Sterile cotton pellet with distilled water (control group); (b) sodium perborate and distilled water; (c) sodium perborate and 10% carbamide peroxide; (d) sodium perborate and 35% hydrogen peroxide; (e) 35% hydrogen peroxide. The teeth were stored in vials containing distilled water and the pH values of the medium surrounding the teeth were analyzed. After 7-day storage, the bleaching agent was removed and replaced by calcium hydroxide, and the distilled water was changed, in which the teeth were kept stored for further 14 days. Measurement of pH of the external medium (distilled water) was performed 7 days after insertion of the bleaching agents, immediately, 7 and 14 days after insertion of the calcium hydroxide. Data were submitted to statistical analysis by the two-way ANOVA and Tukey,s test. There were pH changes of the external medium at 7- day period after bleaching procedures. These results confirmed the diffusion of bleaching agents to the external medium. Calcium hydroxide increased the external medium pH and was effective for pH alkalinization after intracoronal bleaching. Intracoronal bleaching of endodontically treated teeth may cause cervical root resorption. A possible explanation for this process is the passage of bleaching agents to the periodontal tissues yielding an inflammatory process. In an attempt to keep the neutrality of the periodontal pH, the calcium hydroxide has been recommended.Results of this study showed that this material should be always used after intracoronal bleaching.

  3. Topochemical synthesis of alkali-metal hydroxide layers within double- and triple-layered perovskites.

    Science.gov (United States)

    Montasserasadi, Dariush; Mohanty, Debasish; Huq, Ashfia; Heroux, Luke; Payzant, Edward Andrew; Wiley, John B

    2014-02-03

    The formation of alkali-metal hydroxide layers within lamellar perovskites has been accomplished by a two-step topochemical reaction strategy. Reductive intercalation of ALaNb2O7 with alkali metal (A = K, Rb) and RbCa2Nb3O10 with Rb leads to A2LaNb2O7 and Rb2Ca2Nb3O10, respectively. Oxidative intercalation with stoichiometric amounts of water vapor, produced by the decomposition of calcium oxalate monohydrate in a sealed ampule, allows the insertion hydroxide species. Compounds of the form (A2OH)LaNb2O7 (A = K, Rb) and (Rb2OH)Ca2Nb3O10 are accessible. X-ray diffraction data indicates a clear layer expansion of almost 3 Å on the insertion of hydroxide relative to that of the parent. Rietveld refinement of neutron diffraction data collected on deuterated samples of (Rb2OD)LaNb2O7 (P4/mmm space group, a = 3.9348(1) Å, c = 14.7950(7) Å) finds that both rubidium and oxygen species reside in cubic sites forming a CsCl-like interlayer structure between niobate perovskite blocks. Hydrogens, attached to the interlayer oxygens, are disordered over a 4-fold site in the x-y plane and have O-H bond distances (0.98 Å) consistent with known hydroxide species. This synthetic approach expands the library of available topochemical reactions, providing a facile method for the construction of alkali-metal hydroxide layers within receptive perovskite hosts.

  4. Formation of a mixed Fe(II)-Zn-Al layered hydroxide: Effects of Zn co-sorption on Fe(II) layered hydroxide formation and kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Starcher, Autumn N.; Elzinga, Evert J.; Sparks, Donald L.

    2017-08-01

    Previous research demonstrated the formation of single divalent metal (Co, Ni, and ZnAl) and mixed divalent metal (NiZnAl) layered double hydroxide (LDH) phases from reactions of the divalent metal with Al-bearing substrates and soils in both laboratory experiments and in the natural environment. Recently Fe(II)-Al-LDH phases have been found in laboratory batch reaction studies, and although they have yet to be found in the natural environment. Potential locations of Fe(II)-Al-LDH phases in nature include areas with suboxic and anoxic conditions. Because these areas can be environments of significant contaminant accumulation, it is important to understand the possible interactions and impacts of contaminant elements on LDH phase formation. One such contaminant, Zn, can also form as an LDH and has been found to form as a mixed divalent layered hydroxide phase. To understand how Zn impacts the formation of Fe(II)-Al-LDH phase formation and kinetics, 3 mM or 0.8 mM Fe(II) and 0.8 mM Zn were batch reacted with either 10 g/L pyrophyllite or 7.5 g/L γ-Al2O3 for up to three months under anoxic conditions. Aqueous samples were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) and solid samples were analyzed with X-ray absorption spectroscopy (XAS). Shell-by-shell fits of Fe(II) and co-sorption samples with pyrophyllite show the formation of a mixed divalent metal (Fe(II)-Zn-Al) layered hydroxide phase, while Fe(II) and Zn co-sorption samples with γ-Al2O3 produce Fe(II)-Al-LDH phases and Zn in inner-sphere complexation with the γ-Al2O3. This study demonstrates the formation of a mixed divalent metal layered hydroxide and further iterates the importance of sorbent reactivity on LDH phase formation.

  5. Selective Sensing of Fe(3+) and Al(3+) Ions and Detection of 2,4,6-Trinitrophenol by a Water-Stable Terbium-Based Metal-Organic Framework.

    Science.gov (United States)

    Cao, Li-Hui; Shi, Fang; Zhang, Wen-Min; Zang, Shuang-Quan; Mak, Thomas C W

    2015-10-26

    A water-stable luminescent terbium-based metal-organic framework (MOF), {[Tb(L1 )1.5 (H2 O)]⋅3 H2 O}n (Tb-MOF), with rod-shaped secondary building units (SBUs) and honeycomb-type tubular channels has been synthesized and structurally characterized by single-crystal X-ray diffraction. The high green emission intensity and the microporous nature of the Tb-MOF indicate that it can potentially be used as a luminescent sensor. In this work, we show that Tb-MOF can selectively sense Fe(3+) and Al(3+) ions from mixed metal ions in water through different detection mechanisms. In addition, it also exhibits high sensitivity for 2,4,6-trinitrophenol (TNP) in the presence of other nitro aromatic compounds in aqueous solution by luminescence quenching experiments. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

    2017-10-16

    The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. REGIOSELECTIVE REACTIONS OF 3-ALKYL-1-PHENYL-2-PYRAZOLIN-5-ONES WITH ACYL HALIDES IN THE PRECENCE OF NONOSIZED MAGNESIUM HYDROXIDE AS A HIGHLY EFFECTIVE HETEROGENOUS BASE CATALYST Regioselektive Reaktionen von 3-Alkyl-1-PHENYL-2-pyrazolin-5-ONES Mit Acylhalogeniden IN DER PRECENCE DER NONOSIZED MAGNESIUM HYDROXIDE als hochwirksame heterogene BASE CATALYST

    OpenAIRE

    Hassan Sheibani and Bahman Massomi Nejad

    2012-01-01

    4-Acyl-3-alkyl-1-phenyl-2-pyrazolin-5-one derivatives were prepared by the regioselective acylation of 3-alkyl-1-phenyl-2-pyrazolin-5-ones in the presence of base catalysts such as calcium hydroxide [Ca(OH)2], magnesium hydroxide [Mg(OH)2] and nanosized magnesium hydroxide. In the presence of nanosized magnesium hydroxide, excellent yields of products were obtained and reaction times were significantly reduced.

  8. The significance of oxygen as oxides and hydroxides in controlling the abundance and residence times of elements in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    A model is presented which signifies the role of oxygen (as oxides and hydroxides) in controlling the composition of seawater. respective concentration and residence times for the unknown elements can be estimated. Geometric and statistical indices...

  9. Comparative evaluation of the pH of calcium hydroxide powder in contact with carbon dioxide (CO2

    Directory of Open Access Journals (Sweden)

    Amaro de Mendonça Cavalcante

    2010-03-01

    Full Text Available This work involved an evaluation of calcium hydroxide powder in the absence and presence of CO2. 0.12g of calcium hydroxide powder was used for each of 16 aliquots diluted in 100 mL of deionized water and distributed in 2 samples of 8 aliquots. The indices of pOH, [OH-] and [Ca++] were obtained by mathematical calculations after determining the pH. The results demonstrated that in the presence of CO2, calcium hydroxide showed a marked loss of [OH-] and [Ca++] in relation to the decrease in pH. However, the high alkaline pH of the calcium hydroxide powder was preserved in the absence of CO2, maintaining its reparative and antimicrobial properties.

  10. Dynamics of Intercalation/De-Intercalation of Rhodamine B during the Polymorphic Transformation of CdAl Layered Double Hydroxide to the Brucite-Like Cadmium Hydroxide

    KAUST Repository

    Saliba, Daniel

    2016-06-23

    Cadmium-Aluminum layered double hydroxide (CdAl LDH) is thermodynamically unstable and transforms to Cd(OH)2 and Al(OH)3 in a short period of time. We present a reaction-diffusion framework that enables us to use in situ steady-state fluorescence spectroscopy to study the kinetics of intercalation of a fluorescent probe (Rhodamine B (RhB)) during the formation of the CdAl LDH and its de-intercalation upon the conversion of the LDH phase to the β phase (Cd(OH)2). The method involves the diffusion of sodium hydroxide into a hydrogel gel matrix containing the aluminum and cadmium ions as well as the species we wish to incorporate in the interlayers of the LDH. The existence of RhB between the LDH layers and its expel during the transition into the β phase are proved via fluorescence microscopy, XRD and ssNMR. The activation energies of intercalation and de-intercalation of RhB are computed and show dependence on the cationic ratio of the corresponding LDH. We find that the energies of de- intercalation are systematically higher than those of intercalation proving that the dyes are stabilized due to the probe-brucite sheets interactions.

  11. Synthesis of high-density nickel cobalt aluminum hydroxide by continuous coprecipitation method.

    Science.gov (United States)

    Kim, Yongseon; Kim, Doyu

    2012-02-01

    Spherical nickel cobalt aluminum hydroxide (Ni(0.80)Co(0.15)Al(0.05)-hydroxide, NCA) was prepared by a continuous coprecipitation method. A new design of the Al solution and the feeding method was applied, which enabled to prevent rapid precipitation of Al(OH)(3) and to obtain spherical NCA with large enough particle size and high density. The active material (LiNi(0.80)Co(0.15)Al(0.05)O(2) or LNCA) prepared from it showed higher tap-density than that made from NCA prepared by general processes, and homogeneity of Al-distribution was also improved. It is expected that the electrode density of lithium ion batteries adopting LNCA could be improved with the new process proposed in this study.

  12. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    Science.gov (United States)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2015-10-01

    Layered double hydroxides (LDHs) thin films with Mg-Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  13. Potassium hydroxide catalyst supported on palm shell activated carbon for transesterification of palm oil

    Energy Technology Data Exchange (ETDEWEB)

    Baroutian, Saeid; Aroua, Mohamed Kheireddine; Raman, Abdul Aziz Abdul; Sulaiman, Nik Meriam Nik [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2010-11-15

    In this study, potassium hydroxide catalyst supported on palm shell activated carbon was developed for transesterification of palm oil. The Central Composite Design (CCD) of the Response Surface Methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst loading and methanol to oil molar ratio on the production of biodiesel using activated carbon supported catalyst. The highest yield was obtained at 64.1 C reaction temperature, 30.3 wt.% catalyst loading and 24:1 methanol to oil molar ratio. The physical and chemical properties of the produced biodiesel met the standard specifications. This study proves that activated carbon supported potassium hydroxide is an effective catalyst for transesterification of palm oil. (author)

  14. Facile synthesis of CuO nanosheets via the controlled delamination of layered copper hydroxide acetate.

    Science.gov (United States)

    Demel, Jan; Zhigunov, Alexander; Jirka, Ivan; Klementová, Mariana; Lang, Kamil

    2015-08-15

    CuO nanosheets were prepared by the controlled delamination of layered copper hydroxide acetate followed by the in situ solvothermal transformation of hydroxide to oxide. The reaction was performed in 1-butanol in order to prevent recrystallization or nanoparticle aggregation. Analyses by small angle X-ray scattering, transmission electron microscopy, and atomic force microscopy revealed that the CuO nanosheets are approximately 1 nm thin, corresponding to three to four stacked CuO6 octahedral layers. The average lateral size is approximately 5 nm. The nanosheets form stable dispersions in 1-butanol that are suitable for the fabrication of transparent and homogeneous CuO thin films by spin-coating or inkjet printing techniques. The present synthesis is a rare example of the top down strategy leading to the nanometric two-dimensional nanosheets of non-layered oxide materials. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Pore size distribution, strength, and microstructure of portland cement paste containing metal hydroxide waste

    Energy Technology Data Exchange (ETDEWEB)

    Majid, Z.A.; Mahmud, H.; Shaaban, M.G.

    1996-12-31

    Stabilization/solidification of hazardous wastes is used to convert hazardous metal hydroxide waste sludge into a solid mass with better handling properties. This study investigated the pore size development of ordinary portland cement pastes containing metal hydroxide waste sludge and rice husk ash using mercury intrusion porosimetry. The effects of acre and the addition of rice husk ash on pore size development and strength were studied. It was found that the pore structures of mixes changed significantly with curing acre. The pore size shifted from 1,204 to 324 {angstrom} for 3-day old cement paste, and from 956 to 263 {angstrom} for a 7-day old sample. A reduction in pore size distribution for different curing ages was also observed in the other mixtures. From this limited study, no conclusion could be made as to any correlation between strength development and porosity. 10 refs., 6 figs., 3 tabs.

  16. Selective preconcentration of polynuclear aromatic hydrocarbons and polychlorinated biphenyls by in situ metal hydroxide precipitation.

    Science.gov (United States)

    Hess, G G; McKenzie, D E; Hughes, B M

    1986-09-24

    An investigation of selective concentration of analytes from aqueous samples by in situ magnesium hydroxide precipitation, as described by Faltusz, has yielded the following results: the method is selective for polycyclic aromatic hydrocarbons and polychlorinated biphenyls of higher molecular weight: it discriminates strongly against acidic molecules, and other neutral and basic molecules are only partially recovered; a variety of metal hydroxides could evidently be used in this method, but magnesium appears to have practical advantages over some of the others; the reproducibility of analyses on pure water samples is acceptable (ca.20% relative standard deviation), but the results from natural samples show lower recovery and wider variability; a preliminary test, in which this method was used to discriminate against major amounts of interfering solutes, shows promise that this technique might have unique advantages in certain situations.

  17. A NEW PROCESS DEVELOPED FOR SEPARATION OF LIGNIN FROM AMMONIUM HYDROXIDE PRETREATMENT SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, S.; Gorensek, M.; Milliken, C.

    2010-12-14

    A method is described for separating lignin from liquid solutions resulting from the pretreatment of lignocellulosic materials such as switchgrass with ammonium hydroxide. The method involves a sequence of steps including acidification, evaporation, and precipitation or centrifugation that are performed under defined conditions, and results in a relatively pure, solid lignin product. The method is tested on ammonium hydroxide solutions containing lignin extracted from switchgrass. Experimental results show that the method is capable of recovering between 66-95% of dissolved lignin as a precipitated solid. Cost estimates of pilot-scale and industrial-scale expressions of the process indicate that breakeven lignin prices of $2.36/kg and $0.78/kg, respectively, may be obtainable with this recovery method.

  18. Determination of Aluminium Content in Aluminium Hydroxide Formulation by FT-NIR Transmittance Spectroscopy

    DEFF Research Database (Denmark)

    Lai, Xuxin; Zheng, Yiwu; Søndergaard, Ib

    2007-01-01

    A method for determining the aluminium content of an aluminium hydroxide suspension using near infrared (NIR) transmittance spectroscopy has been developed. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used as reference method. The factors influencing the NIR analysis...... by NIR transmission each on five different days, with total of 175 spectra used for the calibration set. The multivariate data analysis technique partial least square regression (PLSR) was applied to build the calibration model. Six batches of aluminium hydroxide samples were used for the test set. ICP......-AES and NIR transmittance spectroscopy exhibit comparable precision and accuracy. The NIR method provides several advantages: no complicated sample preparation; easy to operate; fast and non-destructive. In conclusion, NIR transmittance spectroscopy can be an alternative analytical method for determining...

  19. Effect of an oily calcium hydroxide suspension on early wound healing after nonsurgical periodontal therapy.

    Science.gov (United States)

    Kasaj, Adrian; Willershausen, Brita; Berakdar, Mohamad; Tekyatan, Haki; Sculean, Anton

    2006-03-01

    The purpose of the present study was to evaluate clinically the effect of an oily calcium hydroxide suspension on early wound healing after nonsurgical periodontal therapy. A total of 19 patients with chronic periodontitis were enrolled in the study. Each subject had three sites in each of two contra-lateral jaw quadrants with a probing pocket depth (PPD) of > or =5 mm and bleeding on probing (BoP+). All teeth received scaling and root planing under local anesthesia followed by irrigation with sterile saline. An oily calcium hydroxide suspension (Osteoinductal) was applied subgingivally to the test sites at random. All sites were reexamined after 1, 2 [gingival index (GI) and BoP], and 3 weeks (GI, BoP, and PPD). Treatment success was defined as no signs of GI (GI=0), no BoP (BoP-), and pocket closure (PPDperiodontal therapy, improves early periodontal wound healing.

  20. K (Na)-promoted Ni, Al layered double hydroxide catalysts for the steam reforming of methanol

    Science.gov (United States)

    Qi, Caixia; Amphlett, John C.; Peppley, Brant A.

    Production of hydrogen by methanol steam reforming has been studied over a series of Ni/Al layered double hydroxide catalysts prepared by the co-precipitation method, with the aim to develop a stable catalyst that can be used in a membrane-joint performer at temperatures greater than 300 °C. H 2, CO and CO 2 are generally the major products together with trace amounts of CH 4. The presence of potassium and/or sodium cations was found to improve the activity of methanol conversion. The selectivity for CO 2 rather than CO was better with K ions than Na ions, especially at higher temperatures (e.g. 390-400 °C). Methanol steam reforming over a K-promoted Ni/Al layered double hydroxide catalyst resulted in better activity and similar stability compared to a commercial Cu catalyst.

  1. Electroosmotic dewatering of chalk sludge, iron hydroxide sludge, wet fly ash and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, H.K.; Kristensen, I.V.; Ottosen, L.M.; Villumsen, A. [Dept. of Geology and Geotechnical Engineering, The Technical Univ. of Denmark, Lyngby (Denmark)

    2001-07-01

    Electroosmotic dewatering has been tested in laboratory cells for 4 different porous materials: chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge from enzyme production. In all cases it was possible to remove water when passing electric DC current through the material. Casagrande's coefficients for the three materials where determined at different water contents. In the electroosmotic experiments shown in this work chalk can be dewatered from 40% to 79% DM (dry matter), fly ash from 75 to 82% DM, iron hydroxide sludge from 2.7 to 19% DM and biomass from 3 to 33% DM. The process was not optimised indicating that higher dry matter contents could be achieved. (orig.)

  2. Synthesis and carbon dioxide sorption of layered double hydroxide/silica foam nanocomposites with hierarchical mesostructure

    KAUST Repository

    Fu, Liling

    2014-03-05

    Layered double hydroxides (LDHs) with a hierarchical mesostructure are successfully synthesized on mesoporous silica foams by simple impregnation and hydrothermal treatment. The as-synthesized LDH/silica foam nanocomposites show well-defined mesostructures with high surface areas, large pore volumes, and mesopores of 6-7 nm. The nanocomposites act as carbon dioxide (CO2) sorbents under simulated flue gas conditions. They also exhibit significantly enhanced CO2 capacities under high-pressure conditions and high CO2/N2 and CO2/CH4 selectivities. Respect the hierarchy: Hierarchical mesoporous layered double hydroxide (LDH) nanocomposites with high surface areas and large pore volumes are synthesized by controlled hydrothermal growth of LDH precursors on a mesoporous silica foam. The as-synthesized nanocomposites exhibit a significantly enhanced capacity and selectivity towards carbon dioxide, making them very promising candidates for carbon dioxide (CO2) separation applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Cadmium-Aluminum Layered Double Hydroxide Microspheres for Photocatalytic CO2Reduction

    KAUST Repository

    Saliba, Daniel

    2016-03-30

    We report the synthesis of cadmium-aluminum layered double hydroxide (CdAl LDH) using the reaction-diffusion framework. As the hydroxide anions diffuse into an agar gel matrix containing the mixture of aluminum and cadmium salts at a given ratio, they react to give the LDH. The LDH self-assembles inside the pores of the gel matrix into a unique spherical-porous shaped microstructure. The internal and external morphologies of the particles are studied by electron microscopy and tomography revealing interconnected channels and a high surface area. This material is shown to exhibit a promising performance in the photoreduction of carbon dioxide using solar light. Moreover, the palladium-decorated version shows a significant improvement in its reduction potential at room temperature. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Alternative Sodium Recovery Technology—High Hydroxide Leaching: FY10 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, Lenna A.; Neiner, Doinita; Peterson, Reid A.; Rapko, Brian M.; Russell, Renee L.; Schonewill, Philip P.

    2011-02-04

    Boehmite leaching tests were carried out at NaOH concentrations of 10 M and 12 M, temperatures of 85°C and 60°C, and a range of initial aluminate concentrations. These data, and data obtained during earlier 100°C tests using 1 M and 5 M NaOH, were used to establish the dependence of the boehmite dissolution rate on hydroxide concentration, temperature, and initial aluminate concentration. A semi-empirical kinetic model for boehmite leaching was fitted to the data and used to calculate the NaOH additions required for leaching at different hydroxide concentrations. The optimal NaOH concentration for boehmite leaching at 85°C was estimated, based on minimizing the amount of Na that had to be added in NaOH to produce a given boehmite conversion.

  5. Ultrasound-promoted coating of silk yarn with different morphology of magnesium hydroxide nanostructures.

    Science.gov (United States)

    Khanjani, Somayeh; Morsali, Ali

    2013-03-01

    The growth of magnesium hydroxide nanostructures on silk yarn was achieved by sequential dipping steps in alternating bath of magnesium nitrate and potassium hydroxide under ultrasound irradiation. The effects of ultrasound irradiation, concentration, pH and sequential dipping steps on growth of the Mg(OH)(2) nanostructures have been studied. Morphology of the nanostructures, depending on pH and with decreasing pH from 13 to 8, changed from nanoparticle to nanoneedle. Results show a decrease in the particles size as the concentration and sequential dipping steps increased. The physicochemical properties of the nanostructures were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX). Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Magnesium hydroxide coagulation performance and floc properties in treating high pH reactive orange wastewater.

    Science.gov (United States)

    Liu, Meile; Lu, Jingfang; Wei, Lei; Wang, Kang; Zhao, Jianhai

    2015-01-01

    Application of magnesium hydroxide as a coagulant for treating high pH reactive orange wastewater was studied. The coagulation performance and magnesium hydroxide-reactive orange floc properties were investigated under different dosages, feeding modes and pH values. Flocculation index (FI) was then discussed with controlled experiments using an intelligent particle dispersion analyzer and optimum coagulant dose of 150 mg/L (magnesium ion) was obtained for pH value 12. The results showed that the optimum magnesium ion dose tended to decrease with the increase of initial pH value. One time addition feeding mode led to relatively large FI value and higher removal efficiency compared with other addition modes. All of the flocs under investigation showed a limited capacity for re-growth when they had been previously broken. Based on the changes of zeta potential and floc properties, charge neutralization and precipitate enmeshment were proposed to be the main coagulation mechanisms.

  7. Mg/Al Ordering in Layered Double Hydroxides Revealed by Multinuclear NMR Spectroscopy

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Grey, Clare P.; Sideris, Paul J.

    2008-01-01

    The anion- exchange ability of layered double hydroxides ( LDHs) has been exploited to create materials for use in catalysis, drug delivery, and environmental remediation. The specific cation arrangements in the hydroxide layers of hydrotalcite- like LDHs, of general formula Mg1-x2+Alx3+OH2(Anion......(x/n)(n-)).yH(2)O, have, however, remained elusive, and their elucidation could enhance the functional optimization of these materials. We applied rapid ( 60 kilohertz) magic angle spinning ( MAS) to obtain high- resolution hydrogen- 1 nuclear magnetic resonance ( H-1 NMR) spectra and characterize the magnesium...... and aluminum distribution. These data, in combination with H-1-Al-27 double- resonance and Mg-25 triple- quantum MAS NMR data, show that the cations are fully ordered for magnesium: aluminum ratios of 2:1 and that at lower aluminum content, a nonrandom distribution of cations persists, with no Al3+-Al3+ close...

  8. A Strategy for Hydroxide Exclusion in Nanocrystalline Solid-State Metathesis Products

    Directory of Open Access Journals (Sweden)

    Jiaqi Cheng

    2013-06-01

    Full Text Available We demonstrate a simple strategy to either prevent or enhance hydroxide incorporation in nanocrystalline solid-state metathesis reaction products prepared in ambient environments. As an example, we show that ZnCO3 (smithsonite or Zn5(CO32(OH6 (hydrozincite forms extremely rapidly, in less than two minutes, to form crystalline domains of 11 ±  2 nm and 6 ± 2 nm, respectively. The phase selectivity between these nanocrystalline products is dominated by the alkalinity of the hydrated precursor salts, which may in turn affect the availability of carbon dioxide during the reaction. Thus, unlike traditional aqueous precipitation reactions, our solid-state method offers a way to produce hydroxide-free, nanocrystalline products without active pH control.

  9. Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.; Silvers, Kurt L.; Baker, Aaron B.; Gano, Susan R.; Thornton, Brenda M.

    2000-09-28

    This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantify the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.

  10. Electroosmotic dewatering of chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge

    DEFF Research Database (Denmark)

    Hansen, H.K.; Christensen, Iben Vernegren; Ottosen, Lisbeth M.

    2003-01-01

    . Casagrande's coefficients were determined for the four materials at different water contents. The experiments in this work showed that chalk could be dewatered from 40% to 79% DM (dry matter), fly ash from 75 to 82% DM, iron hydroxide sludge from 2.7 to 19% DM and biomass from 3 to 33% DM by electroosmosis......Electroosmotic dewatering has been tested in laboratory cells on four different porous materials: chalk sludge, iron hydroxide sludge, wet fly ash and biomass sludge from enzyme production. In all cases it was possible to remove water when passing electric DC current through the material....... The process was not optimised indicating that higher dry matter contents could be achieved by electroosmosis. It was possible to relate Casagrande's coefficient directly to the electroosmotic coefficient obtained by dewatering experiments....

  11. Calcium hydroxide induced apical barrier in fractured nonvital immature permanent incisors

    Directory of Open Access Journals (Sweden)

    Vellore K

    2010-06-01

    Full Text Available Management of trauma to an immature permanent incisor is a challenge, especially when the pulp is necrotic. The aim of this study is to discuss the management of fractured maxillary right and left central incisors with immature root apex. Radiographic evaluation revealed that the tooth 11 had convergent apical walls, whereas tooth 21 had parallel apical walls; both the incisors were treated with pure calcium hydroxide paste to induce apical development. Follow-up clinical and radiographic examinations confirmed apical barrier at 3 months. Radiograph of tooth 11 with convergent roots showed continued apical development, whereas tooth 21 showed apical bridging, following which root canal was completed in both the teeth. Therefore, in view of the simplicity of this method, we believe that calcium hydroxide can be reemphasized as one of the treatment alternatives for fractured nonvital immature permanent incisors to induce apical barrier.

  12. Durability of metakaolin geopolymers with various sodium silicate/sodium hydroxide ratios against seawater exposure

    Science.gov (United States)

    Jaya, Nur Ain; Abdullah, Mohd Mustafa Al Bakri; Li, Long-Yuan; Sandu, Andrei Victor; Hussin, Kamarudin; Ming, Liew Yun

    2017-09-01

    This work presents an investigation of the performance of metakaolin geopolymers exposed to the continuous immersion of seawater. The geopolymers were prepared from metakaolin by activating with a mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions and cured at 80°C. The ratios of sodium silicate to sodium hydroxide were varied from 0.20 to 0.32. The result showed that metakaolin geopolymers reduce in strength after immersion in seawater for 28 days. The unexposed samples with highest compressive strength attained greatest strength retention. White deposits were formed on the surface of the geopolymers after the exposure to seawater which was believed due to the depolymerisation process of the geopolymer network. Even so, the metakaolin geopolymers did not substantially change in dimension and remain structurally intact.

  13. Particle size of a new endodontic cement compared to Root MTA and calcium hydroxide

    OpenAIRE

    Soheilipour, Elham; Kheirieh, Sanam; Madani, Majid; Akbarzadeh Baghban, Alireza; Asgary, Saeed

    2009-01-01

    INTRODUCTION: Particle size and distribution can influence the properties of materials. This study analyzed and compared the particle size of Root MTA, calcium hydroxide (CH), and a new endodontic cement called calcium enriched material (CEM). MATERIALS AND METHODS: The particle size of each material was analyzed three times using 0.05 mg of test material with a particle size analyzer. The particle size distribution ranges, the cumulative percentage and the mean of particle sizes were calcula...

  14. Nanoparticles for cultural heritage conservation: calcium and barium hydroxide nanoparticles for wall painting consolidation.

    Science.gov (United States)

    Giorgi, Rodorico; Ambrosi, Moira; Toccafondi, Nicola; Baglioni, Piero

    2010-08-16

    Nanotechnology provides new concepts and materials for the consolidation and protection of wall paintings. In particular, humble calcium and barium hydroxide nanoparticles offer a versatile and highly efficient tool to combat the main degradation processes altering wall paintings. Clear example of the efficacy and potentiality of nanotechnology is represented by the conservation in situ of Maya wall paintings in the archaeological area in Calakmul (Mexico).

  15. A solution blending route to ethylene propylene diene terpolymer/layered double hydroxide nanocomposites

    OpenAIRE

    Acharya, H; Srivastava, SK; Bhowmick, Anil K

    2006-01-01

    AbstractEthylene propylene diene terpolymer (EPDM)/MgAl layered double hydroxide (LDH) nanocomposites have been synthesized by solution intercalation using organically modified LDH (DS-LDH). The molecular level dispersion of LDH nanolayers has been verified by the disappearance of basal XRD peak of DS-LDH in the composites. The internal structures, of the nanocomposite with the dispersion nature of LDH particles in EPDM matrix have been studied by TEM and AFM. Thermogravimetric analysis (TGA)...

  16. Intercalation and structural aspects of macroRAFT agents into MgAl layered double hydroxides

    OpenAIRE

    Dessislava Kostadinova; Ana Cenacchi Pereira; Muriel Lansalot; Franck D’Agosto; Elodie Bourgeat-Lami; Fabrice Leroux; Christine Taviot-Guého; Sylvian Cadars; Vanessa Prevot

    2016-01-01

    Increasing attention has been devoted to the design of layered double hydroxide (LDH)-based hybrid materials. In this work, we demonstrate the intercalation by anion exchange process of poly(acrylic acid) (PAA) and three different hydrophilic random copolymers of acrylic acid (AA) and n-butyl acrylate (BA) with molar masses ranging from 2000 to 4200 g mol−1 synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, into LDH containing magnesium(II) and aluminium(II...

  17. Isolation of Trichoderma harzianum (Rifai) growing on ferric hydroxide mud impregnated with gas oil

    Energy Technology Data Exchange (ETDEWEB)

    Gudin, C. (Lavera Refinery, France); Chater, K.W.A.

    1977-09-01

    In northern France, gas oil-impregnated ferric hydroxide mud was found to support fungal growth. The fungus was identified by the Commonwealth Mycological Institute, Kew, with whom a reference culture has been registered. Experiments indicated that its growth resulted from the biodegradation of the gas oil. It is believed that, in this unusual situation, contaminating hydrocarbons may be removed from the environment by microbial activity.

  18. Resettable fluorescence logic gate based on calcein/layered double hydroxide ultrathin films.

    Science.gov (United States)

    Shi, Wenying; Ji, Xiaolan; Wei, Min; Evans, David G; Duan, Xue

    2012-05-08

    A fluorescent logic gate was fabricated based on calcein/layered double hydroxide ultrathin films (UTFs) via alternate assembly technique, which exhibits high stability, reversibility, and resettability. The logic gate was manipulated by utilizing pH value, Hg(2+) and Cl(-) ion as inputs, and the fluorescence emission of the (calcein/LDH)(16) UTF as output, serving as a three-input logic gate that combines the YES and INHIBIT operation.

  19. Morphologies, Preparations and Applications of Layered Double Hydroxide Micro-/Nanostructures

    Directory of Open Access Journals (Sweden)

    Mingdong Dong

    2010-12-01

    Full Text Available Layered double hydroxides (LDHs, also well-known as hydrotalcite-like layered clays, have been widely investigated in the fields of catalysts and catalyst support, anion exchanger, electrical and optical functional materials, flame retardants and nanoadditives. This feature article focuses on the progress in micro-/nanostructured LDHs in terms of morphology, and also on the preparations, applications, and perspectives of the LDHs with different morphologies.

  20. Pembuatan Etil Ester Sebagai Biodiesel Dari Crude Palm Oil Menggunakan Katalis Choline Hydroxide

    OpenAIRE

    Bestari, Nadya Gema

    2015-01-01

    Biodiesel is generally made by transesterification using alkaline catalyst. Choice of catalyst used, affects greatly the biodiesel produced. Choline Hydroxide (ChOH) catalyst is a basic ionic liquid which has excellently catalytic reactions in the biodiesel production from Crude Palm Oil (CPO). This catalyst is able to produce biodiesel without soap formation and at the end of the reaction, two-three layers formed. They are biodiesel, the catalyst itself and glycerol. It makes ...

  1. Thermodynamic Analysis on the Coprecipitation of Ni-Co-Mn Hydroxide

    Science.gov (United States)

    Li, Ling; Li, Yunjiao; Li, Lin; Chen, Nanxiong; Han, Qiang; Zhang, Xianzhen; Xu, Hu

    2017-10-01

    The thermodynamic data of various species in Ni-H2O, Co-H2O, Mn-H2O, and Ni-Co-Mn-H2O systems were obtained by thermodynamic calculation. The potential-pH diagrams for Ni-H2O, Co-H2O, and Mn-H2O systems at different ion activities at 323 K (50 °C), as well as Ni-Co-Mn-H2O complex systems at activity 1.00 at 298 K, 323 K, and 373 K (25 °C, 50 °C, and 100 °C) were constructed, respectively. The costable regions of Ni(OH)2, Co(OH)2, and Mn(OH)2 are verified to be thermodynamically stable in aqueous solution, which indicates the thermodynamic possibility of Ni-Co-Mn hydroxide coprecipitation. The potential-pH diagrams show that the temperature and ion activity have significant effects on the coprecipitation process. As the temperature increases or the ion activity decreases, the coprecipitation region of the Ni-Co-Mn hydroxide narrows. Moreover, the metal oxides, rather than the metal hydroxide, are more easily formed when the temperature increases. Experimental confirmation was performed to further verify the constructed potential-pH diagrams. The Ni-Co-Mn hydroxide with typical hexagonal CdI2 structure and quasi-spherical morphology was successfully obtained, and the SEM results show the uniform distribution of the elements Ni, Co, and Mn. The experimental results confirm the reliability of the prediction of thermodynamics analysis.

  2. Histological response of human pulps capped with calcium hydroxide and a self-etch adhesive containing an antibacterial component

    OpenAIRE

    Ambalavanan Parthasarathy; Kamat, Sharad B.; Mamta Kamat; Krishnamurthy Haridas Kidiyoor

    2016-01-01

    Aim: To compare human pulp tissue response following direct pulp capping with calcium hydroxide and a self-etch adhesive containing antibacterial component. Materials and Methods: Sixty-six erupted sound premolars scheduled to be extracted for orthodontic reasons were selected from 17 human subjects. Pulp exposures were made. Direct pulp capping was then performed using calcium hydroxide and a self-etch adhesive containing antibacterial component in its primer. The teeth were then restor...

  3. Analysis of pH and release of calcium of association between melaleuca alternifolia oil and calcium hydroxide

    Directory of Open Access Journals (Sweden)

    Maiara GIONGO

    2017-03-01

    Full Text Available Abstract Introduction The use of intracanal medications with antimicrobial properties is essential for decontaminating root canals during endodontic treatment. Calcium hydroxide is used for this because of its excellent properties. Melaleuca alternifolia oil has shown medicinal importance by demonstrating antifungal and bactericidal action against proven human pathogens. Objective To evaluate the physical and chemical aspects such as pH and calcium release, of Melaleuca alternifolia oil associated with calcium hydroxide, during different time intervals. Material and method Calcium hydroxide powder was added to vehicles to reach a concentration of 72mg / 0.1mL. Three groups were formed: Group I: Calcium Hydroxide + Distilled Water; Group II: Calcium hydroxide + Propylene Glycol; Group III: Calcium hydroxide + Melaleuca oil. The pH of each group was measured after time intervals of 10 minutes; 24 and 48 hours; 7, 15 and 30 days after tooling by a pH meter. Calcium release was analyzed by atomic absorption spectrometry equipped with a calcium hollow cathode lamp. Data were statistically analyzed by using the Kruskall-Wallis and Dunn test. Result Group II showed high pH, similar to group III that remained uniform at 15 and 30 days. Calcium release that began after 24 hours, was similar in Groups II and III, and showed a peak release in 48 hours. Conclusion The association of Melaleuca oil with calcium hydroxide showed good results in the pH and calcium release analyses, and showed action similar to that of propylene glycol + calcium hydroxide.

  4. Vertical root fracture associated with prolonged use of calcium hydroxide during apexification. A case report.

    Directory of Open Access Journals (Sweden)

    Jennifer Ribadeneira

    2015-04-01

    Full Text Available Apexification is a procedure performed in young permanent teeth to promote apical closure and root elongation if Hertwig’s epithelial sheath has not been irreversibly damaged. The objective of this article is to describe vertical root fracture as a complication during apexification when using calcium hydroxide for extended periods of time. The patient was a 9-year-old female student who went to the Faculty of Dentistry of the Universidad Andres Bello in Concepcion. She presented strong and spontaneous pain and pressure and swelling on the left cheek. Clinically, the vestibule of the lower left first molar (3.6 was edematous and had pus. Radiographically, lesions and open apices were seen in the apical zone. Diagnosis was pulp necrosis and acute apical abscess. The tooth was trephined to perform intracanal drainage and an oral antibiotic was prescribed. Afterwards, she was referred to the endodontic specialty office. The selected treatment was apexification with calcium hydroxide until achieving the formation of an apical barrier. When the apical formation was observed, a vertical root fracture was discovered as well, confirming that the use of calcium hydroxide should not be prolonged because dehydration processes lead to weakening of the walls and therefore of the tooth

  5. Effects of irrigation solutions and Calcium hydroxide dressing on root canal treatments of periapical lesions

    Directory of Open Access Journals (Sweden)

    Vita Nirmala

    2006-03-01

    Full Text Available The preparation of root canal in endodontic treatment plays an important role in treating non vital teeth with periapical lesion. Some factors influence the success of root canal treatment in short and long terms are the irrigation of root canal using antiseptic solution and the use of root canal medicament. The aim of this literature study is to determined the effect of irrigation solution and Calcium hydroxide dressing in root canal treatment of periapical lesions. The use of root canal medicament during the endodontic treatment could sterilized and decreased the number of pathogenic microorganism of root canal. An effective root canal irrigation solution must be able to dissolve organic and anorganic debris, lubricate endodontic instruments, disinfect microorganisms, non toxic and economical. The best irrigation solution has maximum antimicrobial effect with minimum toxicity. Division of calcium hydroxide into Calcium and hydroxyl ions is responsible for alkalinization of cavity, subsequently it makes the condition of cavity to be inappropriate for bacterial endotoxin in vitro as well as in vivo, and considered as the only clinically effective medicament in inactivating bacterial endotoxin. Calcium hydroxide is the only medication which has the ability to clinically inactive bacterial endotoxin in vitro in vivo and accepted as the best of root canal medication.

  6. Pulsed laser deposition of Mg-Al layered double hydroxide with Ag nanoparticles

    Science.gov (United States)

    Matei, A.; Birjega, R.; Vlad, A.; Luculescu, C.; Epurescu, G.; Stokker-Cheregi, F.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2013-03-01

    Powdered layered double hydroxides (LDHs)—also known as hydrotalcite-like (HT)—compounds have been widely studied due to their applications as catalysts, anionic exchangers or host materials for inorganic or organic molecules. Assembling thin films of nano-sized LDHs onto flat solid substrates is an expanding area of research, with promising applications as sensors, corrosion-resistant coatings, components in optical and magnetic devices. The exploitation of LDHs as vehicles to carry dispersed metal nanoparticles onto a substrate is a new approach to obtain composite thin films with prospects for biomedical and optical applications. We report the deposition of thin films of Ag nanoparticles embedded in a Mg-Al layered double hydroxide matrix by pulsed laser deposition (PLD). The Ag-LDH powder was prepared by co-precipitation at supersaturation and pH = 10 using aqueous solutions of Mg and Al nitrates, Na hydroxide and carbonate, and AgNO3, having atomic ratios of Mg/Al = 3 and Ag/Al = 0.55. The target to be used in laser ablation experiments was a dry pressed pellet obtained from the prepared Ag-LDH powder. Three different wavelengths of a Nd:YAG laser (266, 532 and 1064 nm) working at a repetition rate of 10 Hz were used. X-Ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and secondary ions mass spectrometry (SIMS) were used to investigate the structure, surface morphology and composition of the deposited films.

  7. OPTIMIZATION OF TIME REACTION AND HYDROXIDE ION CONCENTRATION ON FLAVONOID SYNTHESIS FROM BENZALDEHYDE AND ITS DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Sri Handayani

    2010-06-01

    Full Text Available The aim of this research is to determine the optimum time of reaction and concentration of hydroxide ion on chalcone, 4-methoxychalcone and 3,4-dimethoxychalcone synthesis. Chalcone and its derivatives were synthesized by dissolving KOH in ethanol followed by dropwise addition of acetophenone and benzaldehyde. Then, the mixture was stirred for several hours. Three benzaldehydes has been used, i.e : benzaldehyde, p-anysaldehyde and veratraldehyde. The time of reaction was varied for, 12, 18, 24, 30 and 36 hours. Furthermore, on the optimum reaction time for each benzaldehyde the hydroxyl ion concentration was varied from 5,7,9,11 and 13%(w/v. The results of this research suggested that the optimum time of chalchone synthesis was 12 hours, while, 4-methoxychalcone and 3,4-dimethoxychalcone were 30 hours. The optimum concentration of hydroxide ion of chalcone synthesis was 13% and for 4-methoxychalcone and 3,4-dimethoxychalcone were 11%. Keywords: Chalcone synthesis, time of reaction, hydroxide ion concentration.

  8. Regenerative endodontic treatment (revascularization) of immature necrotic molars medicated with calcium hydroxide: a case series.

    Science.gov (United States)

    Cehreli, Zafer C; Isbitiren, Beste; Sara, Sezgi; Erbas, Gizem

    2011-09-01

    Revascularization is an emerging regenerative treatment protocol with little published data available in immature molar teeth. The present case series demonstrates the outcome of revascularization treatment with intracanal medicament of calcium hydroxide in immature necrotic molars. Immature necrotic permanent first molars (n = 6) of patients 8-11 years old were treated by a revascularization protocol that used 2.5% NaOCl irrigation, medication with calcium hydroxide placed in the coronal third of the root canals, induction of apical bleeding, and coronal sealing with white mineral trioxide aggregate. Among the treated teeth, 4 molars had undergone prior root canal instrumentation by the referring dentists. National Institutes of Health Image-J program with TurboReg plug-in was used for standardization of the radiographs and to determine the increase in root length and root width. After a follow-up period of 10 months, all teeth demonstrated radiographic evidence of complete periapical healing, progressive thickening of dentinal walls, and continued apical development in the absence of clinical symptoms. Two uninstrumented molars showed a positive response to cold testing at 9 months. On the basis of a follow-up period of 10 months, the present cases demonstrate a favorable outcome of the revascularization procedure in immature necrotic molars by using calcium hydroxide medication in the coronal third of the root canals. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

    Science.gov (United States)

    Rau, Gregory Hudson [Castro Valley, CA

    2012-05-15

    A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

  10. The role of SO42- surface distribution in arsenic removal by iron oxy-hydroxides

    Science.gov (United States)

    Tresintsi, S.; Simeonidis, K.; Pliatsikas, N.; Vourlias, G.; Patsalas, P.; Mitrakas, M.

    2014-05-01

    This study investigates the contribution of chemisorbed SO42- in improving arsenic removal properties of iron oxy-hydroxides through an ion-exchange mechanism. An analytical methodology was developed for the accurate quantification of sulfate ion (SO42-) distribution onto the surface and structural compartments of iron oxy-hydroxides synthesized by FeSO4 precipitation. The procedure is based on the sequential determination of SO42- presence in the diffuse and Stern layers, and the structure of these materials as defined by the sulfate-rich environments during the reaction and the variation in acidity (pH 3-12). Physically sorbed SO42-, extracted in distilled water, and physically/chemically adsorbed ions on the oxy-hydroxide's surface leached by a 5 mM NaOH solution, were determined using ion chromatography. Total sulfate content was gravimetrically measured by precipitation as BaSO4. To validate the suggested method, results were verified by X-ray photoelectron and Fourier-transformed infrared spectroscopy. Results showed that low precipitation pH-values favor the incorporation of sulfate ions into the structure and the inner double layer, while under alkaline conditions ions shift to the diffuse layer.

  11. Electrocatalytic performance evaluation of cobalt hydroxide and cobalt oxide thin films for oxygen evolution reaction

    Science.gov (United States)

    Babar, P. T.; Lokhande, A. C.; Pawar, B. S.; Gang, M. G.; Jo, Eunjin; Go, Changsik; Suryawanshi, M. P.; Pawar, S. M.; Kim, Jin Hyeok

    2018-01-01

    The development of an inexpensive, stable, and highly active electrocatalyst for oxygen evolution reaction (OER) is essential for the practical application of water splitting. Herein, we have synthesized an electrodeposited cobalt hydroxide on nickel foam and subsequently annealed in an air atmosphere at 400 °C for 2 h. In-depth characterization of all the films using X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) techniques, which reveals major changes for their structural, morphological, compositional and electrochemical properties, respectively. The cobalt hydroxide nanosheet film shows high catalytic activity with 290 mV overpotential at 10 mA cm-2 and 91 mV dec-1 Tafel slope and robust stability (24 h) for OER in 1 M KOH electrolyte compared to cobalt oxide (340 mV). The better OER activity of cobalt hydroxide in comparison to cobalt oxide originated from high active sites, enhanced surface, and charge transport capability.

  12. Hydroxide Self-Feeding High-Temperature Alkaline Direct Formate Fuel Cells.

    Science.gov (United States)

    Li, Yinshi; Sun, Xianda; Feng, Ying

    2017-05-22

    Conventionally, both the thermal degradation of the anion-exchange membrane and the requirement of additional hydroxide for fuel oxidation reaction hinder the development of the high-temperature alkaline direct liquid fuel cells. The present work addresses these two issues by reporting a polybenzimidazole-membrane-based direct formate fuel cell (DFFC). Theoretically, the cell voltage of the high-temperature alkaline DFFC can be as high as 1.45 V at 90 °C. It has been demonstrated that a proof-of-concept alkaline DFFC without adding additional hydroxide yields a peak power density of 20.9 mW cm -2 , an order of magnitude higher than both alkaline direct ethanol fuel cells and alkaline direct methanol fuel cells, mainly because the hydrolysis of formate provides enough OH - ions for formate oxidation reaction. It was also found that this hydroxide self-feeding high-temperature alkaline DFFC shows a stable 100 min constant-current discharge at 90 °C, proving the conceptual feasibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment

    Directory of Open Access Journals (Sweden)

    Daniele Chiriu

    2014-01-01

    Full Text Available Pottery samples from the Pompeii archaeological site were investigated by IR Raman spectroscopy and EDAX measurements. The analysis of the Raman spectra of the surfaces reveals the presence calcium hydroxide (peak at about 780 cm−1 while the calcium carbonate is totally absent. The comparative studies on the carbonation effect of the surfaces were performed on laboratory grown samples of calcium hydroxide. The samples were treated at high temperature and exposed to different ambient conditions, and the analysis suggests that the original surfaces of Roman pottery were scattered by calcium hydroxide (limewash before the cooking process in the furnace. The result of this surface treatment not only permits a vitrification of the surfaces but also seems to reduce the content of CO2 in the furnace atmosphere and then obtain a more oxidant ambient during the cooking of the pottery. These results give new insights on the real degree of knowledge of the Romans about the art of ceramics and more generally about chemistry and technologies.

  14. Highly Efficient Air Desulfurization on Self-Assembled Bundles of Copper Hydroxide Nanorods.

    Science.gov (United States)

    Giannakoudakis, Dimitrios A; Jiang, Mingyung; Bandosz, Teresa J

    2016-11-23

    Copper hydroxide and copper hydroxyl nitrate were successfully synthesized from copper nitrate. A slight alteration of a base addition pathway led to entirely different chemical and crystal structures. Structural, morphological, and surface chemical features were analyzed using various physical and chemical methods. The copper hydroxide texture consists of self-assembled bundles of nanorods with a diameter between 15 and 40 nm. They are stack together forming platelet-like particles. In the case of the copper hydroxyl nitrate, platelet-like particles with a smooth surface were detected. The fully hydroxylated sample showed a considerably higher surface area and mesoporous volume than those of copper hydroxyl nitrate. Both synthesized materials were used as air desulfurization media at moist or dry conditions. The results indicate a supreme chemical adsorption of H2S on copper hydroxide. Moisture in air has a positive effect on the adsorption performance. In humid conditions, almost 0.9 mol H2S/mol of Cu(OH)2 was adsorbed. CuS with almost a stoichiometric ratio was a product of surface reactions. The color change of the powder from sapphire blue to dark brown during the adsorption can be used as a fast indication of the adsorbent exhaustion level.

  15. Comparison of the Penetration Depth of Conventional and Nano-Particle Calcium Hydroxide into Dentinal Tubules.

    Science.gov (United States)

    Zand, Vahid; Mokhtari, Hadi; Hasani, Aila; Jabbari, Golchin

    2017-01-01

    The aim of this in vitro study was to evaluate and compare the penetration depth of conventional (CH) and nano-particle calcium hydroxide (NCH) into dentinal tubules. Ninety human single-rooted teeth were instrumented by RaCe rotary system and after chemomechanical preparation were randomly divided in two equal groups (n=45). In the first group conventional CH and in the other NCH was used as intracanal medicament. After 2 weeks of incubation all roots were intentionally split at longitudinal axis and prepared for scanning electron microscope (SEM) observation. Three zones of each root, coronal, middle and apical were examined under SEM and the maximum penetration depth of the dressing material into dentinal tubules was recorded for each zone. Data were analyzed using the independent sample t test and the level of significance was set at 0.05. In all of the three zones, NCH group had greater penetration depth than CH (Ppenetration depth increased from the apical section to the coronal. The depth of penetration of nano-particle calcium hydroxide into the dentinal tubules was significantly higher than that of conventional calcium hydroxide. The lowest penetration depth was observed in apical zone in both groups.

  16. Toxicity of copper hydroxide, dithianon, fluazinam, tebuconazole and pyraclostrobin to Didymella applanata isolates from Serbia.

    Science.gov (United States)

    Mirković, Biljana; Tanović, Brankica; Hrustić, Jovana; Mihajlović, Milica; Stević, Milan; Delibašić, Goran; Vukša, Petar

    2015-01-01

    A study of the in vitro sensitivity of 10 isolates of Didymella applanata to copper hydroxide, dithianon, fluazinam, tebuconazole and pyraclostrobin, was conducted. The isolates were derived from diseased raspberry canes sampled during 2013 at five localities in western part of Serbia, known as the main raspberry growing region of the country. Prior to sensitivity testing experimental conditions for radial growth assay were optimized. The results showed that the temperature of 22 °C, oatmeal agar medium and 12/12 hrs light/ darkness light regimen provided the best conditions for sensitivity tests. Most of D. applanata isolates were sensitive to the tested fungicides. The narrowest range of EC50 values was recorded for tebuconazole (1.42-2.66 mg L(-1)). The widest range of EC50 values was obtained for pyraclostrobin, ranging from 0.17 mg L(-1) to 55.33 mg L(-1). The EC50 values for the studied isolates were 39.48-51.19 mg L(-1) for copper hydroxide, 12.12-18.73 mg L(-1) for dithianon and 5.72-42.56 mg L(-1) for fluazinam. According to resistance factor values, all D. applanata isolates were sensitive to copper hydroxide, dithianon and tebuconazole. Among tested isolates, six were highly resistant to pyraclostrobin (RFs in the range of 207.1-325.5) and two moderately resistant to fluazinam (RFs were 3 and 7.4), respectively.

  17. Studies on MgNi-Based Metal Hydride Electrode with Aqueous Electrolytes Composed of Various Hydroxides

    Directory of Open Access Journals (Sweden)

    Jean Nei

    2016-08-01

    Full Text Available Compositions of MgNi-based amorphous-monocrystalline thin films produced by radio frequency (RF sputtering with a varying composition target have been optimized. The composition Mg52Ni39Co3Mn6 is identified to possess the highest initial discharge capacity of 640 mAh·g−1 with a 50 mA·g−1 discharge current density. Reproduction in bulk form of Mg52Ni39Co3Mn6 alloy composition was prepared through a combination of melt spinning (MS and mechanical alloying (MA, shows a sponge-like microstructure with >95% amorphous content, and is chosen as the metal hydride (MH alloy for a sequence of electrolyte experiments with various hydroxides including LiOH, NaOH, KOH, RbOH, CsOH, and (C2H54N(OH. The electrolyte conductivity is found to be closely related to cation size in the hydroxide compound used as 1 M additive to the 4 M KOH aqueous solution. The degradation performance of Mg52Ni39Co3Mn6 alloy through cycling demonstrates a strong correlation with the redox potential of the cation in the alkali hydroxide compound used as 1 M additive to the 5 M KOH aqueous solution. NaOH, CsOH, and (C2H54N(OH additions are found to achieve a good balance between corrosion and conductivity performances.

  18. Structural Differentiation between Layered Single (Ni) and Double Metal Hydroxides (Ni–Al LDHs) Using Wavelet Transformation

    Energy Technology Data Exchange (ETDEWEB)

    Siebecker, Matthew G. [University of Delaware, Delaware Environmental Institute; Sparks, Donald L. [University of Delaware, Delaware Environmental Institute

    2017-09-07

    Layered double hydroxides (LDHs) are anionic clays important in disciplines such as environmental chemistry, geochemistry, and materials science. Developments in signal processing of extended X-ray absorption fine structure (EXAFS) data, such as wavelet transformation (WT), have been used to identify transition metals and Al present in the hydroxide sheets of LDHs. The WT plots of LDHs should be distinct from those of isostructural single metal hydroxides. However, no direct comparison of these minerals appears in the literature using WT. This work systematically analyzes a suite of Ni-rich mineral standards, including Ni–Al LDHs, single metal Ni hydroxides, and Ni-rich silicates using WT. The results illustrate that the WT plots for α-Ni(OH)2 and Ni–Al LDHs are often indistinguishable from each other, with similar two-component plots for the different mineral types. This demonstrates that the WT of the first metal shell often cannot be used to differentiate an LDH from a single metal hydroxide. Interlayer anions adsorbed to the hydroxide sheet of α-Ni(OH)2 affect the EXAFS spectra and are not visible in the FT but are clearly resolved and discrete in the WT.

  19. An In Vitro Comparative Study on the Antimicrobial Effects of Bioglass 45S5 vs. Calcium Hydroxide on Enterococcus Faecalis.

    Science.gov (United States)

    Mehrvarzfar, Payman; Akhavan, Hengameh; Rastgarian, Hossein; Mohammadzade Akhlagi, Nahid; Soleymanpour, Reza; Ahmadi, Anahid

    2011-01-01

    An ideal intracanal medicament should be able to eliminate any remaining intracanal microorganism. The aim of this study was to compare the antimicrobial effects of Bioglass 45S5 with calcium hydroxide on Enterococcus (E) faecalis in-vitro. Direct exposure test (DET) was used to evaluate the antimicrobial effect of Bioglass 45S5, calcium hydroxide and normal saline (control group) on 80 paper cones contaminated with E. faecalis suspension. All samples were aseptically transferred into BHI culture medium to quantify microbial concentration in periods of 1, 24, 48 and 72 hours. Turbidity of the culture medium was measured via optical density (OPD) method with a spectrophotometer (wavelength=540nm). Results were then analysed statistically using student t-test. Mean difference of optical density between Bioglass 45S5 and calcium hydroxide appeared insignificant within 1 hour of the test period (P>0.05); however calcium hydroxide showed significantly greater antimicrobial properties after 24 hours (PBioglass 45S5 and calcium hydroxide exhibited antimicrobial effects against E. faecalis, neither attained complete eradication of bacteria. However, calcium hydroxide seemed to have superior disinfecting effect.

  20. Mechanochemical synthesis of finite particle of layered double hydroxide-acetate intercalation compound: Swelling, thin film and ion exchange

    Science.gov (United States)

    Kuramoto, Kyoko; Intasa-Ard, Soontaree (Grace); Bureekaew, Sareeya; Ogawa, Makoto

    2017-09-01

    Acetate intercalated Mg-Al layered double hydroxide was successfully synthesized by the solid-state reactions between magnesium acetate and aluminum hydroxide as the starting materials using a planetary mil. The acetate intercalated Mg-Al layered double hydroxide prepared by the present solid-state reaction was finite particle and was processed into stable aqueous suspension with variable transparency and viscosity depending on the concentration. By drying the suspension on a substrate under nitrogen atmosphere, thin film (with the thickness of several micrometers) of the acetate intercalated Mg-Al layered double hydroxide with the basal plane oriented parallel to the substrate was obtained. The ion exchange ability of the film, which is as an advantage of the acetate form of layered double hydroxide, was shown by the ion exchange with coumarin-3-carboxylate to give a photoluminescent film. The solid-solid reaction is advantageous for the preparation of layered double hydroxides due to the simple and eco-friendly nature (no solvent) of the operation, lower possibility of carbonate contamination and finite particles of the products.

  1. Sodium terbium(III polyphosphate

    Directory of Open Access Journals (Sweden)

    Abdelghani Oudahmane

    2010-04-01

    Full Text Available Single crystals of the title compound, NaTb(PO34, were obtained by solid-state reaction. This compound belongs to type II of long-chain polyphosphates with the general formula AIBIII(PO34. It is isotypic with the NaNd(PO34 and NaEr(PO34 homologues. The crystal structure is built up of infinite crenelated chains of corner-sharing PO4 tetrahedra with a repeating unit of four tetrahedra. These chains, extending parallel to [100], are linked by isolated TbO8 square antiprisms, forming a three-dimensional framework. The Na+ ions are located in channels running along [010] and are surrounded by six oxygen atoms in a distorted octahedral environment within a cut-off distance <2.9 Å.

  2. Oxidation of Dodecanoate Intercalated Iron(II)–Iron(III) Layered Double Hydroxide to Form 2D Iron(III) (Hydr)oxide Layers

    DEFF Research Database (Denmark)

    Huang, Li‐Zhi; Ayala‐Luis, Karina B.; Fang, Liping

    2013-01-01

    .00(OH)5.31(C12H23O2)0.66(SO4)0.51 and FeIII3O2.18(OH)3.13(C12H23O2)0.56(SO4)0.47, respectively. oxGRC12 has the same planar layer structure as GRC12, as revealed by identical powder X‐ray diffraction patterns. The electrostatic interactions between the interlayer dodecanoate (C12) anions and the iron...... between the alkyl chains of the intercalated dodecanoate anions play a crucial role in stabilizing the structure and hindering the collapse of the iron(II)–iron(III) (hydr)oxide structure during oxidation. This is the first report describing the formation of a stable planar layered octahedral iron...

  3. Density-Functional Tight-Binding Investigation of the Structure, Stability and Material Properties of Nickel Hydroxide Nanotubes.

    Science.gov (United States)

    Jahangiri, Soran; Mosey, Nicholas J

    2017-11-03

    Nickel hydroxide is a material composed of two-dimensional layers that can be rolled up to form cylindrical nanotubes belonging to a class of inorganic metal hydroxide nanotubes that are candidates for applications in catalysis, energy storage, and microelectronics. The stabilities and other properties of this class of inorganic nanotubes have not yet been investigated in detail. The present study uses self-consistent-charge density-functional tight-binding calculations to examine the stabilities, mechanical properties, and electronic properties of nickel hydroxide nanotubes along with the energetics associated with the adsorption of water by these systems. The tight-binding model was parametrized for this system based on the results of first-principles calculations. The stabilities of the nanotubes were examined by calculating strain energies and performing molecular dynamics simulations. The results indicate that single-walled nickel hydroxide nanotubes are stable at room temperature, which is consistent with experimental investigations. The nanotubes possess size-dependent mechanical properties that are similar in magnitude to those of other inorganic nanotubes. The electronic properties of the nanotubes were also found to be size-dependent and small nickel oxyhydroxide nanotubes are predicted to be semiconductors. Despite this size-dependence, both the mechanical and electronic properties were found to be almost independent of the helical structure of the nanotubes. The calculations also show that water molecules have higher adsorption energies when binding to the interior of the nickel hydroxide nanotubes when compared to adsorption in nanotubes formed from other two-dimensional materials such as graphene. The increased adsorption energy is due to the hydrophilic nature of nickel hydroxide. Due to the broad applications of nickel hydroxide, the nanotubes investigated here are also expected to be used in catalysis, electronics, and clean energy production.

  4. Formation of iron (hydr)oxides during the abiotic oxidation of Fe(II) in the presence of arsenate.

    Science.gov (United States)

    Song, Jia; Jia, Shao-Yi; Yu, Bo; Wu, Song-Hai; Han, Xu

    2015-08-30

    Abiotic oxidation of Fe(II) is a common pathway in the formation of Fe (hydr)oxides under natural conditions, however, little is known regarding the presence of arsenate on this process. In hence, the effect of arsenate on the precipitation of Fe (hydr)oxides during the oxidation of Fe(II) is investigated. Formation of arsenic-containing Fe (hydr)oxides is constrained by pH and molar ratios of As:Fe during the oxidation Fe(II). At pH 6.0, arsenate inhibits the formation of lepidocrocite and goethite, while favors the formation of ferric arsenate with the increasing As:Fe ratio. At pH 7.0, arsenate promotes the formation of hollow-structured Fe (hydr)oxides containing arsenate, as the As:Fe ratio reaches 0.07. Arsenate effectively inhibits the formation of magnetite at pH 8.0 even at As:Fe ratio of 0.01, while favors the formation of lepidocrocite and green rust, which can be latterly degenerated and replaced by ferric arsenate with the increasing As:Fe ratio. This study indicates that arsenate and low pH value favor the slow growth of dense-structured Fe (hydr)oxides like spherical ferric arsenate. With the rapid oxidation rate of Fe(II) at high pH, ferric (hydr)oxides prefer to precipitate in the formation of loose-structured Fe (hydr)oxides like lepidocrocite and green rust. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Density-functional tight-binding investigation of the structure, stability and material properties of nickel hydroxide nanotubes

    Science.gov (United States)

    Jahangiri, Soran; Mosey, Nicholas J.

    2018-01-01

    Nickel hydroxide is a material composed of two-dimensional layers that can be rolled up to form cylindrical nanotubes belonging to a class of inorganic metal hydroxide nanotubes that are candidates for applications in catalysis, energy storage, and microelectronics. The stabilities and other properties of this class of inorganic nanotubes have not yet been investigated in detail. The present study uses self-consistent-charge density-functional tight-binding calculations to examine the stabilities, mechanical properties, and electronic properties of nickel hydroxide nanotubes along with the energetics associated with the adsorption of water by these systems. The tight-binding model was parametrized for this system based on the results of first-principles calculations. The stabilities of the nanotubes were examined by calculating strain energies and performing molecular dynamics simulations. The results indicate that single-walled nickel hydroxide nanotubes are stable at room temperature, which is consistent with experimental investigations. The nanotubes possess size-dependent mechanical properties that are similar in magnitude to those of other inorganic nanotubes. The electronic properties of the nanotubes were also found to be size-dependent and small nickel oxyhydroxide nanotubes are predicted to be semiconductors. Despite this size-dependence, both the mechanical and electronic properties were found to be almost independent of the helical structure of the nanotubes. The calculations also show that water molecules have higher adsorption energies when binding to the interior of the nickel hydroxide nanotubes when compared to adsorption in nanotubes formed from other two-dimensional materials such as graphene. The increased adsorption energy is due to the hydrophilic nature of nickel hydroxide. Due to the broad applications of nickel hydroxide, the nanotubes investigated here are also expected to be used in catalysis, electronics, and clean energy production.

  6. Evaluation of Hydroxyl Ion Diffusion in Dentin and Injectable Forms and a Simple Powder-Water Calcium Hydroxide Paste: An in Vitro Study

    OpenAIRE

    Eftekhar, Behrooz; Moghimipour, Eskandar; Eini, Ebrahim; Jafarzadeh, Mansour; Behrooz, Narges

    2014-01-01

    Background: Intra canal medicaments are used to reduce the number of bacteria and reinfection in endodontic procedures. Calcium Hydroxide was introduced to endodontics by Herman as an intracanal antimicrobial agent. Objectives: The aim of this study was to present an injectable formulation of calcium hydroxide then compare the final pH of this new formulation with Metapaste and evaluate the effect of a mixture of Calcium Hydroxide powder with water on human extracted teeth. Patients and Metho...

  7. Determination of a Polymeric Hindered Amine Light Stabilizer in Polypropylene Formulated with Magnesium Hydroxide Flame Retardant by Reactive Thermal Desorption-Gas Chromatography

    National Research Council Canada - National Science Library

    TAGUCHI, Yoshihiko; ISHIDA, Yasuyuki; OHTANI, Hajime; BEKKU, Hiroyuki; SERA, Masaya

    2004-01-01

    A polymeric hindered amine light stabilizer (HALS), Tinuvin 622 (MW = 4000), in PP materials formulated with a magnesium hydroxide flame retardant was determined by reactive thermal desorption (RTD...

  8. Diode Laser and Calcium Hydroxide for Elimination of Enterococcus Faecalis in Root Canal

    Directory of Open Access Journals (Sweden)

    Neda Naghavi

    2014-06-01

    Full Text Available Introduction: The ultimate goal of endodontic treatment is to eliminate the bacterial infection in the root canal system. While mechanical debridement combined with chemical irrigation removes the bulk of microorganisms, residual bacteria are readily detectable in approximately one-half of teeth just prior to obturation. Laser light can be used to destroy bacteria. This in vitro study was performed to evaluate the effect of diode laser and calcium hydroxide on mono-infected dental canals.Methods: Fifty five single-rooted human premolars were prepared and contaminated with Enterococcus faecalis. After three weeks of incubation, the samples were divided into three experimental groups (n = 15 and two control groups (n = 5. In the first and second groups, the teeth were rinsed for 5 min with either sterile saline or 5.25% NaOCl and irradiated with a 810-nm diode laser at 1.5 W output for 5 × 4s. In the third group, the teeth were rinsed with 5.25% NaOCl and then Ca(OH2 paste was inserted in the canals for 1 week. Intracanal bacterial sampling was done and the samples were plated to determine the CFU count. Results: 5.25% NaOCl plus laser was as effective as calcium hydroxide and significantly more effective than sterile saline (P>0.05 in elimination of E. faecalis. Complete elimination of E. faecalis was seen only for the one week calcium hydroxide treatment. Conclusion: Combination therapy with NaOCl irrigation and diode laser irradiation can be recommended as an effective treatment option for elimination of E. faecalis from the root canal system.

  9. Hydroxide precursors to produce nanometric YCrO{sub 3}: Characterization and conductivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Durán, A., E-mail: dural@cnyn.unam.mx [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800, Ensenada, B.C. (Mexico); Meza F, C. [Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología, Km. 107 Carretera Tijuana-Ensenada, Apartado Postal 14, C.P. 22800, Ensenada, B.C. (Mexico); Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

    2012-06-15

    Highlights: ► Y/Cr mixed hydroxide was precipitated with gaseous ammonia. ► The hydroxide treated at 1373 K formed YCrO{sub 3} crystals with 20 nm diameter. ► Electrical properties were different than those found in other methods of synthesis. ► E{sub act} suggests small-polarons as conduction mechanisms. -- Abstract: A precursor to produce perovskite-type YCrO{sub 3} was precipitated by bubbling gaseous ammonia into an yttrium/chromium salts solution. X-ray diffraction showed that the as-prepared powders were amorphous. Thermal treatment between 1273 and 1373 K, leads to formation of polycrystalline YCrO{sub 3} with crystal sizes around 20 nm. High resolution X-ray photoelectron spectra showed uniform chemical environment for yttrium and chromium in the amorphous hydroxide and crystalline YCrO{sub 3}. Shifts between Y 3d{sub 5/2} and Cr 2p{sub 3/2} binding energy suggest redistribution or charge transfer between yttrium and chromium ions in the YCrO{sub 3} structure. The electrical properties of YCrO{sub 3}, whose precursors were precipitated with gaseous ammonia are different than those prepared by combustion synthesis. Electrical conductivity presents a sudden increase at ∼473 K, which is associated to the grain size and morphology of the crystallites. The redistribution of charge between Y(III) and Cr(III) is thermally activated by the hopping of small-polarons, which are characterized by the Arrhenius law as the conductive mechanism.

  10. Structural characterization of nickel oxide/hydroxide nanosheets produced by CBD technique

    Energy Technology Data Exchange (ETDEWEB)

    Taşköprü, T., E-mail: ttaskopru@anadolu.edu.tr [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey); Department of Physics, Çankırı Karatekin University, Çankırı 18100 (Turkey); Zor, M.; Turan, E. [Department of Physics, Anadolu University, Eskişehir 26470 (Turkey)

    2015-10-15

    Graphical abstract: SEM images of (a) as deposited β-Ni(OH)2 and (b) NiO samples deposited with pH 10 solution. The inset figures shows the absorbance spectra of (a) β-Ni(OH)2 and (b) NiO samples. - Highlights: • The formation of β-Ni(OH){sub 2} and NiO were confirmed with XRD, SEM, FT-IR and Raman. • Porous nickel oxide was synthesized after heat treatment of nickel hydroxide. • The increase in pH value changes the nanoflake structure to hexagonal nanosheet. • On increasing the pH from 8 to 11, the band gap decreases from 3.52 to 3.37 eV. - Abstract: Nickel hydroxide samples were deposited onto glass substrates using Ni(NO{sub 3}){sub 2}·6H{sub 2}O and aqueous ammonia by chemical bath deposition technique. The influence of pH of solution was investigated by means of X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, optical absorption and BET analysis. The as-deposited samples were identified as β-Ni(OH){sub 2}, were transformed into NiO after heat treatment in air at 500 °C for 2 h. Porous nickel oxide nanosheets are obtained by heating nickel hydroxide nanosheets. The optical transitions observed in the absorbance spectra below optical band gap is due to defects or Ni{sup 2+} vacancies in NiO samples. The band gap energy of NiO samples changes between 3.37 and 3.52 eV depending on the pH values.

  11. Mineral trioxide aggregate or calcium hydroxide direct pulp capping: an analysis of the clinical treatment outcome.

    Science.gov (United States)

    Mente, Johannes; Geletneky, Beate; Ohle, Marc; Koch, Martin Jean; Friedrich Ding, Paul Georg; Wolff, Diana; Dreyhaupt, Jens; Martin, Nicolas; Staehle, Hans Joerg; Pfefferle, Thorsten

    2010-05-01

    The use of mineral trioxide aggregate (MTA) might improve the prognosis of teeth after pulp exposure. The treatment outcome of teeth after direct pulp capping, either with mineral trioxide aggregate (MTA) or calcium hydroxide (controls), was investigated, taking into account possible confounding factors. One hundred forty-nine patients treated between 2001 and 2006 who received direct pulp capping treatment in 167 teeth met the inclusion criteria. Treatment was performed by supervised undergraduate students (72%) and dentists (28%). Assessment of clinical and radiographic outcomes was performed by calibrated examiners 12-80 months after treatment (median, 27 months). One hundred eight patients (122 treated teeth) were available for follow-up (72.5% recall rate). A successful outcome was recorded for 78% of teeth (54 of 69) in the MTA group and for 60% of teeth (32 of 53) in the the calcium hydroxide group. The univariate analysis (generalized estimation equations model [GEE model] showed a significant difference in the success rate (odds ratio [OR], 2.36; 95% confidence interval [CI], 1.05-5.32; P = .04). In the multiple analysis (GEE model), the OR is marginally inside the nonsignificant range (OR, 0.43; 95% CI, 0.19-1.02; P = .05) when conspicuous confounding factors are stabilized (univariate analysis). Multiple analysis showed that teeth that were permanently restored >or=2 days after capping had a significantly worse prognosis in both groups (OR, 0.24; 95% CI, 0.09-0.66; P = .01). MTA appears to be more effective than calcium hydroxide for maintaining long-term pulp vitality after direct pulp capping. The immediate and definitive restoration of teeth after direct pulp capping should always be aimed for. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Evaluation of pH and calcium ion diffusion from calcium hydroxide pastes and MTA.

    Science.gov (United States)

    Sáez, María Del M; López, Gabriela L; Atlas, Diana; de la Casa, María L

    2017-04-01

    The aim of this ex vivo study was to evaluate changes in pH and calcium ion diffusion through root dentin from calcium hydroxide (Ca (OH) 2) and mineral trioxide aggregate (MTA) pastes at 7, 30 and 60 days; and the relationship between pH and ion diffusion. Thirty-two human premolars were used. Crowns were sectioned and root canals instrumented and filled in with the following preparations: 1) Ca(OH) 2 + distilled water (n=7); 2) Ca(OH) 2 + 0.1% chlorhexidine gluconate (n=7); 3) MTA + distilled water (n=7); 4) MTA + 0.1% chlorhexidine gluconate (CHX) (n=7); 5) distilled water (n=2) (control); 6) 0.1% chlorhexidine gluconate (n=2) (control). The apex and coronary opening were sealed with IRM. Roots were placed in Eppendorf tubes with 1 ml distilled water at 37°C and 100% humidity. At baseline, 7, 30 and 60 days, pH was measured with pH meter, and calcium ion content in the solution was analyzed by atomic absorption spectrophotometry. The data were statistically analyzed using ANOVA, simple linear regression analysis and Pearson's correlation test. The highest pH values were achieved with calcium hydroxide pastes at 60 days (p ≤ 0.05). Calcium ions were released in all groups. The calcium hydroxide paste with distilled water at 60 days had the highest calcium ion value (p ≤ 0.01). There was a positive correlation between calcium and pH values. Sociedad Argentina de Investigación Odontológica.

  13. Improving Corrosion Resistance and Biocompatibility of Magnesium Alloy by Sodium Hydroxide and Hydrofluoric Acid Treatments

    Directory of Open Access Journals (Sweden)

    Chang-Jiang Pan

    2016-12-01

    Full Text Available Owing to excellent mechanical property and biodegradation, magnesium-based alloys have been widely investigated for temporary implants such as cardiovascular stent and bone graft; however, the fast biodegradation in physiological environment and the limited surface biocompatibility hinder their clinical applications. In the present study, magnesium alloy was treated by sodium hydroxide (NaOH and hydrogen fluoride (HF solutions, respectively, to produce the chemical conversion layers with the aim of improving the corrosion resistance and biocompatibility. The results of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR and X-ray photoelectron spectroscopy (XPS indicated that the chemical conversion layers of magnesium hydroxide or magnesium fluoride were obtained successfully. Sodium hydroxide treatment can significantly enhance the surface hydrophilicity while hydrogen fluoride treatment improved the surface hydrophobicity. Both the chemical conversion layers can obviously improve the corrosion resistance of the pristine magnesium alloy. Due to the hydrophobicity of magnesium fluoride, HF-treated magnesium alloy showed the relative better corrosion resistance than that of NaOH-treated substrate. According to the results of hemolysis assay and platelet adhesion, the chemical surface modified samples exhibited improved blood compatibility as compared to the pristine magnesium alloy. Furthermore, the chemical surface modified samples improved cytocompatibility to endothelial cells, the cells had better cell adhesion and proliferative profiles on the modified surfaces. Due to the excellent hydrophilicity, the NaOH-treated substrate displayed better blood compatibility and cytocompatibility to endothelial cells than that of HF-treated sample. It was considered that the method of the present study can be used for the surface modification of the magnesium alloy to enhance the corrosion resistance and biocompatibility.

  14. Influence of calcium hydroxide intracanal dressings on the prognosis of teeth with endodontically induced periapical lesions.

    Science.gov (United States)

    Weiger, R; Rosendahl, R; Löst, C

    2000-05-01

    This prospective clinical study explored the influence of calcium hydroxide as an interappointment dressing on the healing of periapical lesions associated with pulpless teeth that had not been endodontically treated previously. This was achieved by comparing the prognosis after a two-visit root canal treatment with that following a one-visit treatment. Seventy-three patients were recruited having one tooth with an endodontically induced lesion. Of these patients, 67 could be re-examined. Calcium hydroxide was placed in the instrumented root canals of 31 teeth for at least one week and the treatment finished at the second visit. Thirty-six teeth were root canal treated at one visit. The criteria for success were the absence of signs and symptoms indicating an acute phase of periapical periodontitis and radiographically a periodontal ligament space of normal width. Methods for event time analysis were used to evaluate and compare the prognosis of both treatment approaches. The probability that complete periapical healing will take place increased continuously with the length of the observation period. In both treatment groups the likelihood that the root canal treatment yields a success within an observation time of five years exceeded 90%. A statistically significant difference between the two treatment groups could not be detected. From a microbiological perspective, one-visit root canal treatment created favourable environmental conditions for periapical repair similar to the two-visit therapy when calcium hydroxide was used as antimicrobial dressing. One-visit root canal treatment is an acceptable alternative to two-visit treatment for pulpless teeth associated with an endodontically induced lesion.

  15. Hydroxide stabilization as a new tool for ballast disinfection: Efficacy of treatment on zooplankton

    Science.gov (United States)

    Moffitt, Christine M.; Watten, Barnaby J.; Barenburg, Amber; Henquinet, Jeffrey

    2015-01-01

    Effective and economical tools are needed for treating ship ballast to meet new regulatory requirements designed to reduce the introduction of invasive aquatic species from ship traffic. We tested the efficacy of hydroxide stabilization as a ballast disinfection tool in replicated, sequential field trials on board the M/V Ranger III in waters of Lake Superior. Ballast water was introduced into each of four identical 1,320 L stainless steel tanks during a simulated ballasting operation. Two tanks were treated with NaOH to elevate the pH to 11.7 and the remaining two tanks were held as controls without pH alteration. After retention on board for 14–18 h, CO2-rich gas recovered from one of two diesel propulsion engines was sparged into tanks treated with NaOH for 2 h to force conversion of NaOH ultimately to sodium bicarbonate, thereby lowering pH to about 7.1. Prior to gas sparging, the engine exhaust was treated by a unique catalytic converter/wet scrubber process train to remove unwanted combustion byproducts and to provide cooling. The contents of each tank were then drained and filtered through 35-µm mesh plankton nets to collect all zooplankton. The composition and relative survival of zooplankton in each tank were evaluated by microscopy. Zooplankton populations were dominated by rotifers, but copepods and cladocerans were also observed. Hydroxide stabilization was 100% effective in killing all zooplankton present at the start of the tests. Our results suggest hydroxide stabilization has potential to be an effective and practical tool to disinfect ship ballast. Further, using CO2 released from the ship engine reduces emissions and the neutralized by product, sodium bicarbonate, can have beneficial impacts on the aquatic environment.

  16. Protective Activity of the Mixtures of Pine Oil and Copper Hydroxide against Bacterial Spot and Anthracnose on Red Pepper

    Directory of Open Access Journals (Sweden)

    Jae-Woo Soh

    2014-09-01

    Full Text Available This research was performed to examine the protective activities of the mixtures of pine oil and copper hydroxide against bacterial spot and anthracnose on pepper plants. As for bacterial spot, the treatment of pine oil alone displayed high disease incidence (59.6% and low protective effect (28.9%. In comparison, the treatments of mixtures and copper hydroxide alone showed protective activities of 66.8-76.1%. The mixture of pine oil and copper hydroxide (4:1 suppressed the most effectively bacterial spot on pepper. On the other hand, the mixture of pine oil and copper hydroxide (4:1 also showed the strongest protective effect against pepper anthracnose among the 4 treatments tested; its disease incidence and disease control value were 49.8% and 41.7%, respectively. The other treatments showed low protective activities with control values of 7.4-17.1%. These results suggested that the mixture of pine oil and copper hydroxide (4:1 can be used for the environmental-friendly disease control of bacterial spot and anthracnose on pepper.

  17. [The effect of a combined nanoparticulate/calcium hydroxide medication on the biofilm of Enterococcus faecalis in starvation phase].

    Science.gov (United States)

    Zhang, Fu-hua; Li, Mao; Wei, Zhi-jun; Zhao, Bing

    2016-02-01

    To evaluate the efficacy of Ca(OH)2 with a silver nanoparticle suspension to eliminate the biofilm of Enterococcus faecalis (E. faecalis) in starvation phase. The biofilm models of E.faecalis in the starvation phase were built in vitro with 256 extracted human single-rooted teeth, and the methods of plate culture count and crystal violet biofilm assay were applied to determine the effect of the inhibition of different intracanal medicament (silver nanoparticle with calcium hydroxide, silver nanoparticle alone, calcium hydroxide alone ) to the biofilm of E. faecalis in starvation phase at 1 and 7 days. The negative control group was treated with sterile water only. Statistical analysis was carried out with SPSS 13.0 software package. The inhibitory effect of Ca(OH)2+nanosilver on the biofilms of E. faecalis was found more significant than that of silver nanoparticle alone and calcium hydroxide alone at 1 and 7 days, and silver nanoparticle alone was more effective than calcium hydroxide alone. No difference in antimicrobial properties was observed between the two time points in the Ca(OH)2+silver nanoparticle group and silver nanoparticle group, while higher antimicrobial efficacy was observed in the Ca(OH)2 group after 7 days than 1 day. Silver nanoparticle with calcium hydroxide has an obvious inhibitory effect on the biofilm of E.faecalis in the starvation phase.

  18. Zimmer slipstream magnesium hydroxide recovery demonstration. Volume I of II. Final report, April 1, 1993--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Dravo Lime has for many years supplied magnesium containing lime in the ranges of 3-6% MgO. Several years ago Dravo Lime realized the potential operating savings its FGD customers could benefit from if magnesium could be recovered from FGD waste streams. As a result, several different proprietary processes have been developed for the recovery of magnesium hydroxide. These recovery processes include steps for magnesium hydroxide separation, purification, and crystal growth. The process implemented at The Cincinnati Gas Electric Company`s Wm. H. Zimmer Station was piloted by Dravo Lime Company at Allegheny Power System`s Mitchell Station near Monongahela, PA during the fourth quarter in 1989 and first quarter in 1990. This pilot work was the foundation for further development of the ThioClear process at Dravo`s pilot plant at CG&E Miami Fort Station. The ThioClear process is a closed loop version of the magnesium hydroxide recovery process with the same unit operations and products but also including an absorber tower for scrubbing flue gas. Testing at Miami Fort of the ThioClear process led to improvements in separation of magnesium hydroxide from gypsum that are part of the magnesium hydroxide recovery process installed at Zimmer Station.

  19. Influence of elemental impurities in aluminum hydroxide adjuvant on the stability of inactivated Japanese Encephalitis vaccine, IXIARO®.

    Science.gov (United States)

    Schlegl, Robert; Weber, Michael; Wruss, Jürgen; Low, Donald; Queen, Kirsten; Stilwell, Shaun; Lindblad, Erik B; Möhlen, Michael

    2015-11-04

    Aluminum hydroxide is a critical raw material in the production of many vaccines. It is used as an adjuvant in the formulation of the final bulk vaccine, and for this it must meet the specifications of the European Pharmacopeia Monograph. We investigated whether vaccine stability was affected by the presence of trace amounts of elemental impurities in commercially available aluminum hydroxide. The content of residual elemental impurities in commercially available aluminum hydroxide was determined by selective and sensitive inductively coupled-plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy. We found significant differences between different suppliers, but also between different lots from the same supplier. Inactivated Japanese encephalitis vaccine, IXIARO(®), was used to study the effect of residual metals in aluminum hydroxide on antigen stability. We propose that antigen degradation occurred via a pathway involving the metal-catalyzed, auto-oxidation of a process-related impurity (sulfite). Thus, sulfite auto-oxidation resulted in antigen degradation when residual Cu was present at elevated concentrations in aluminum hydroxide. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Can a hydroxide ligand trigger a change in the coordination number of magnesium ions in biological systems?

    Science.gov (United States)

    Kluge, Stefan; Weston, Jennie

    2005-03-29

    Density functional (B3LYP) calculations indicate that a hydroxide ligand is capable of triggering a reduction in the coordination number of Mg(2+) ions from 6 to 5. Since this could be quite relevant in the mode of action of magnesium-containing enzymes (especially hydrolases in which a metal-bound hydroxide species is believed to play a crucial role), we have performed a systematic deprotonation study of biologically relevant magnesium complexes. We explicitly calculated the preferred coordination number of [MgL(1)(x)L(2)(y)L(3)(z)](2)(-)(n) species at the B3LYP/aug-cc-pVTZ level of theory. L(1), L(2), and L(3) represent combinations of water, hydroxide, carboxylate (models Glu and Asp), ammonia ligands (models Lys and His residues), and fluoride ions. As expected, Mg(2+) exclusively prefers an octahedral coordination geometry with H(2)O, HCO(2)(-), or NH(3). Surprisingly, one hydroxide ligand triggers a change to a trigonal bipyramidal geometry. The isoelectronic fluoride ion behaves similarly. When two OH(-) are present, a tetrahedral coordination geometry is preferred. We postulate that a hydroxide (in addition to its role as an active nucleophile) could be employed by magnesium-containing enzymes to trigger a differential coordination behavior.

  1. Coagulation-adsorption of reactive orange from aqueous solution by freshly formed magnesium hydroxide: mixing time and mechanistic study.

    Science.gov (United States)

    Zhao, Jianhai; Shi, Huanhuan; Liu, Meile; Lu, Jingfang; Li, Wenpu

    2017-04-01

    The utilization of magnesium hydroxide was successfully carried out to remove reactive orange by coagulation-adsorption from aqueous solution. The coagulation-adsorption mechanisms and magnesium hydroxide-reactive orange floc property were analyzed through zeta potential, scanning electron microscope (SEM), X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR). Flocculation Index was then discussed with controlled experiments using intelligent Particle Dispersion Analyzer (iPDA) and optimum rapid mixing time of 90 s was obtained for pH 12. The results of this study indicate that charge neutralization and adsorption are proposed to be the main coagulation mechanisms. The FT-IR spectra and SEM showed that reactive orange was adsorbed on the magnesium hydroxide surface during coagulation and adsorption. Freshly generated magnesium hydroxide can effectively remove reactive orange and the removal efficiency can reach 96.7% and 46.3% for coagulation and adsorption, respectively. Adsorption process accounts for 48% of the whole coagulation experiment. The removal efficiency decreased significantly with increasing magnesium hydroxide formation time.

  2. Synthesis of nanocomposite 2-methyl-4-chlorophenoxyacetic acid with layered double hydroxide: physicochemical characterization and controlled release properties

    Energy Technology Data Exchange (ETDEWEB)

    Sarijo, Siti Halimah, E-mail: izaddinizaddin@yahoo.com; Ghazali, Sheikh Ahmad Izaddin Sheikh Mohd [Faculty of Applied Sciences, Universiti Teknologi MARA (Malaysia); Hussein, Mohd Zobir [Universiti Putra Malaysia, Department of Chemistry, Faculty of Science (Malaysia); Sidek, Norizzah Jaafar [Faculty of Applied Sciences, Universiti Teknologi MARA (Malaysia)

    2013-01-15

    A new organic-inorganic hybrid nanocomposite Zn-Al-MCPA-layered double hydroxide (ZAM) was prepared by intercalation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) into Zn-Al-layered double hydroxide (ZAL) at various concentration of MCPA ranging from 0.1 to 0.7 M. The pH of the synthesis was kept constant at 7.5. Well-ordered hybrid nanocomposite was obtained with 0.4 M MCPA with an expansion of basal spacing from 8.9 Angstrom-Sign in the ZAL to 19.7 Angstrom-Sign in the resulting nanocomposite. The FTIR spectra of the nanocomposite show resemblance peaks of the MCPA and Zn-Al-layered double hydroxide indicating the inclusion of MCPA into the layered double hydroxide. The average particle size of ZAL and ZAM in this study was 115 and 128 nm, respectively. Percentage loading of MCPA was found to be 45.0 % (w/w), calculated based on the percentage of carbon in the sample. The release of MCPA into various aqueous solution was found to be dependent to the anion in the aqueous solution in the order of phosphate > sulfate > chloride with the percentage release of 80, 44, and 8%, respectively. This study shows that Zn-Al-layered double hydroxide can be used as a host carrier for herbicide, MCPA, with controlled release capability.

  3. Synthesis of nanocomposite 2-methyl-4-chlorophenoxyacetic acid with layered double hydroxide: physicochemical characterization and controlled release properties

    Science.gov (United States)

    Sarijo, Siti Halimah; Ghazali, Sheikh Ahmad Izaddin Sheikh Mohd; Hussein, Mohd Zobir; Sidek, Norizzah Jaafar

    2013-01-01

    A new organic-inorganic hybrid nanocomposite Zn-Al-MCPA-layered double hydroxide (ZAM) was prepared by intercalation of 2-methyl-4-chlorophenoxyacetic acid (MCPA) into Zn-Al-layered double hydroxide (ZAL) at various concentration of MCPA ranging from 0.1 to 0.7 M. The pH of the synthesis was kept constant at 7.5. Well-ordered hybrid nanocomposite was obtained with 0.4 M MCPA with an expansion of basal spacing from 8.9 Å in the ZAL to 19.7 Å in the resulting nanocomposite. The FTIR spectra of the nanocomposite show resemblance peaks of the MCPA and Zn-Al-layered double hydroxide indicating the inclusion of MCPA into the layered double hydroxide. The average particle size of ZAL and ZAM in this study was 115 and 128 nm, respectively. Percentage loading of MCPA was found to be 45.0 % (w/w), calculated based on the percentage of carbon in the sample. The release of MCPA into various aqueous solution was found to be dependent to the anion in the aqueous solution in the order of phosphate > sulfate > chloride with the percentage release of 80, 44, and 8 %, respectively. This study shows that Zn-Al-layered double hydroxide can be used as a host carrier for herbicide, MCPA, with controlled release capability.

  4. Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation

    Science.gov (United States)

    Bhat, Pooja B.; Bhat, Badekai Ramachandra

    2016-03-01

    Ultrasmall nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) nanocatalyst was synthesized by traditional co-precipitation method and was examined for oxidation of aromatic alcohols to carbonyls using hydrogen peroxide as terminal oxidant. A very high surface area of 104.55 m2 g-1 was achieved for ferromagnetic MnFe2O4 and 100.50 m2 g-1 for superparamagnetic NiFe2O4, respectively. Efficient oxidation was observed due to the synergized effect of nickel hydroxide (bronsted base) on Lewis center (Fe) of the nanocatalyst. Catalyst recycling experiments revealed that the ultrasmall nanocatalyst can be easily recovered by external magnet and applied for nearly complete oxidation of alcohols for at least five successive cycles. Furthermore, the nickel hydroxide functionalised ultrasmall nanocatalyst exhibited higher efficiency for benzyl alcohol oxidation compared to Ni(OH)2, bare MnFe2O4 and NiFe2O4. Higher conversion rate was observed for nickel hydroxide functionalised NiFe2O4 compared to MnFe2O4. Ultrasmall magnetic nickel hydroxide functionalised nanocatalyst showed environmental friendly, greener route for the oxidation of alcohols without significant loss in activity and selectivity within successive runs.

  5. EFFECT OF SODIUM HYDROXIDE CONCENTRATION ON FRESH PROPERTIES AND COMPRESSIVE STRENGTH OF SELF-COMPACTING GEOPOLYMER CONCRETE

    Directory of Open Access Journals (Sweden)

    FAREED AHMED MEMON

    2013-02-01

    Full Text Available This paper reports the results of the laboratory tests conducted to investigate the effect of sodium hydroxide concentration on the fresh properties and compressive strength of self-compacting geopolymer concrete (SCGC. The experiments were conducted by varying the concentration of sodium hydroxide from 8 M to 14 M. Test methods such as Slump flow, V-Funnel, L-box and J-Ring were used to assess the workability characteristics of SCGC. The test specimens were cured at 70°C for a period of 48 hours and then kept in room temperature until the day of testing. Compressive strength test was carried out at the ages of 1, 3, 7 and 28 days. Test results indicate that concentration variation of sodium hydroxide had least effect on the fresh properties of SCGC. With the increase in sodium hydroxide concentration, the workability of fresh concrete was slightly reduced; however, the corresponding compressive strength was increased. Concrete samples with sodium hydroxide concentration of 12 M produced maximum compressive strength.

  6. Studies on the toxicities of aluminium hydroxide and calcium phosphate as immunological adjuvants for vaccines.

    Science.gov (United States)

    Goto, N; Kato, H; Maeyama, J; Eto, K; Yoshihara, S

    1993-01-01

    Aluminium hydroxide (Al) and calcium phosphate (Ca) have been used for many years as immunological adjuvants for biologicals. We investigated the toxic effects of both adjuvants with different physical properties. Al-gel elicited vascular permeability-increasing and toxic effects to macrophages (M phi), while its haemolytic effect was weak. Ca-gel elicited a significantly stronger haemolytic effect, but no other toxic effect. Incubation of M phi or polymorphonuclear leucocytes with Al-suspension resulted in the largest release of lactate dehydrogenase. Ca-suspension caused haemolysis of about 50% of that caused by Ca-gel.

  7. Anodic stripping voltammetry of nickel ions and nickel hydroxide nanoparticles at boron-doped diamond electrodes

    Science.gov (United States)

    Musyarofah, N. R. R.; Gunlazuardi, J.; Einaga, Y.; Ivandini, T. A.

    2017-04-01

    Anodic stripping voltammetry (ASV) of nickel ions in phosphate buffer solution (PBS) have been investigated at boron-doped diamond (BDD) electrodes. The deposition potential at 0.1 V (vs. Ag/AgCl) for 300 s in 0.1 M PBS pH 3 was found as the optimum condition. The condition was applied for the determination of nickel contained in nickel hydroxide nanoparticles. A linear calibration curve can be achieved of Ni(OH)2-NPs in the concentration range of x to x mM with an estimated limit of detection (LOD) of 5.73 × 10-6 mol/L.

  8. Application of Ozone Related Processes to Mineralize Tetramethyl Ammonium Hydroxide in Aqueous Solution

    OpenAIRE

    Chyow-San Chiou; Kai-Jen Chuang; Ya-Fen Lin; Hua-Wei Chen; Chih-Ming Ma

    2013-01-01

    Tetramethyl ammonium hydroxide (TMAH) is an anisotropic etchant used in the wet etching process of the semiconductor industry and is hard to degrade by biotreatments when it exists in wastewater. This study evaluated the performance of a system combined with ultraviolet, magnetic catalyst (SiO2/Fe3O4) and O3, denoted as UV/O3, to TMAH in an aqueous solution. The mineralization efficiency of TMAH under various conditions follows the sequence: UV/O3 > UV/H2O2/O3 > H2O2/SiO2/Fe3O4/O3 > H2O2/O3 >...

  9. 1.2.5. Synthesis, crystal structure and catalytic activity of 2-methoxycarbonylethyldichlorotin hydroxide

    Directory of Open Access Journals (Sweden)

    Wenchao Ding, Han Lu, Wugai An, Xu Yingying, Laijin Tian*

    2014-04-01

    Full Text Available Abstract: 2-methoxycarbonylethyldichlorotin hydroxide, CH3OCOCH2CH2SnCl2(OH ( 1, has been synthesized by hydrolysis reaction and characterized by elemental analysis, FTIR, 1H NMR spectroscopy, and X-ray single crystal diffraction. Compound  1 is a centrosymmetric dimmer, and the tin atom approximates to octahedral geometry via an intramolecular carbonyl- to-tin coordination and hydroxo-bridging. The compound display high selectivity and good catalysis activity on the transesterification reaction of ethyl acetoacetate with an alcohol. Supporting information: FT-IR, 1H NMR, X-Ray, GC/MS analyses, Cif file. 

  10. Preformed magnesium hydroxide precipitate for second-step concentration of enteroviruses from drinking and surface waters.

    Science.gov (United States)

    Vilagines, P; Sarrette, B; Vilagines, R

    1982-07-01

    A method is described for the second-step concentration of viruses from large volumes of drinking and surface waters. Seeded viruses present in the first eluate, performed with 50 mM glycine buffer, pH 11.5, were adsorbed on a preformed magnesium hydroxide precipitate. After low-speed centrifugation they were desorbed and adjusted to pH 7 with McIlvaine citrate-phosphate buffer. In these experimental conditions 90% of the viruses present in the 300-mL first eluate were reconcentrated in a final volume of 40 mL. The recovery efficiency was independent of either virus concentration or water quality.

  11. Review of the synthesis of layered double hydroxides: a thermodynamic approach

    Directory of Open Access Journals (Sweden)

    Bravo-Suárez Juan J.

    2004-01-01

    Full Text Available The synthesis of layered double hydroxides (LDHs by hydrothermal-LDH reconstruction and coprecipitation methods is reviewed using a thermodynamic approach. A mixture model was used for the estimation of the thermodynamics of formation of LDHs. The synthesis and solubility of LDHs are discussed in terms of standard molar Gibbs free energy change of reaction. Data for numerous divalent and trivalent metals as well as for some monovalent and tetravalent metals that may be part of the LDH structure have been compiled. Good agreement is found between theoretical and experimental data. Diagrams and tables for the prediction of possible new LDH materials are provided.

  12. Preparation and evaluation of PEGylated phospholipid membrane coated layered double hydroxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Mina Yan

    2016-06-01

    Full Text Available The aim of the present study was to develop layered double hydroxide (LDH nanoparticles coated with PEGylated phospholipid membrane. By comparing the size distribution and zeta potential, the weight ratio of LDH to lipid materials which constitute the outside membrane was identified as 2:1. Transmission electron microscopy photographs confirmed the core-shell structure of PEGylated phospholipid membrane coated LDH (PEG-PLDH nanoparticles, and cell cytotoxicity assay showed their good cell viability on Hela and BALB/C-3T3 cells over the concentration range from 0.5 to 50 μg/mL.

  13. Preparation and inhibition properties of molybdate intercalated ZnAlCe layered double hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Huajie; Wang, Jihui, E-mail: jhwang@tju.edu.cn; Zhang, Yu; Hu, Wenbin

    2016-09-05

    ZnAlCe layered double hydroxide intercalated by molybdate (ZnAlCe−MoO{sub 4} LDH) was successfully synthesized by using co-precipitation method, and the morphology, structure of ZnAlCe−MoO{sub 4} LDH were observed and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. The inhibition behavior of ZnAlCe−MoO{sub 4} LDH for Q235 steel in 3.5%NaCl solution was determined by polarization curves, electrochemical impedance spectroscopy (EIS), inductively coupled plasma mass spectrometer (ICP-MS) and X-ray photoelectron spectrometer (XPS) methods. The results shows that the synthesized ZnAlCe−MoO{sub 4} LDH has a lamellar structure with a particle size of 0.1–2.0 μm, an average thickness of 30 nm, and a basal plane spacing of 0.898 nm. Compared with the addition of ZnAl layered double hydroxide intercalated by nitrate (ZnAl−NO{sub 3} LDH) and ZnAl layered double hydroxide intercalated by molybdate (ZnAl−MoO{sub 4} LDH) in 3.5% NaCl solution, Q235 steel in 3.5%NaCl + ZnAlCe−MoO{sub 4} LDH solution has a lower corrosion current density, larger polarization resistance and a higher inhibition efficiency. The addition of ZnAlCe−MoO{sub 4} LDH will reduce the chloride concentration in 3.5% NaCl solution by the anion exchanged with molybdate, and improve the corrosion resistance of Q235 steel owing to the formation of passive film with the composition of ferrous or iron molybdate and deposition film with zinc and cerium hydroxides. - Highlights: • ZnAlCe−MoO{sub 4} LDH compound was successfully synthesized by co-precipitation method. • ZnAlCe−MoO{sub 4} LDH has a better inhibition effect to Q235 steel in 3.5%NaCl solution. • The Cl{sup −} ions in solution was partially exchanged with MoO{sub 4}{sup 2−} ions in host layers. • The passive film and deposition film were formed by the release of LDH compound.

  14. Interactions of amino acids with aluminum octacarboxyphthalocyanine hydroxide. Experimental and DFT studies

    OpenAIRE

    Kliber-Jasik, Marta; Broda, Ma?gorzata A.; Maro?, Anna; Nackiewicz, Joanna

    2017-01-01

    The influence of albumin and amino acids (l-serine, glycine, l-histidine, l-tryptophan, l-cysteine) on the properties of aluminum octacarboxyphthalocyanine hydroxide (Al(OH)PcOC) was investigated in a phosphate buffer (pH?8.0). Particular attention was paid to the spectroscopic properties and photostability of Al(OH)PcOC. The effect of albumin or amino acids on the photodegradation of Al(OH)PcOC was examined in water using red light: 685?nm and daylight irradiation. Analysis of kinetic curves...

  15. Reconstruction Effects on Surface Properties of Co/Mg/Al Layered Double Hydroxide

    Directory of Open Access Journals (Sweden)

    Denis SOKOL

    2017-08-01

    Full Text Available Layered double hydroxides having different cationic (Mg2+, Co2+, Al3+ composition were successfully synthesized by the low supersaturation method. The samples were thermally decomposed and reconstructed using water and nitrate media at different temperatures. X-ray powder diffraction analysis, X-ray fluorescence analysis, thermogravimetry and BET/BJH methods were used to investigate the differences between the directly obtained layered materials and those after the reconstruction process.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.15184

  16. Nickel-cobalt hydroxide nanosheets arrays on Ni foam for pseudocapacitor applications

    Science.gov (United States)

    Pu, Jun; Tong, Yao; Wang, Shubo; Sheng, Enhong; Wang, Zhenghua

    2014-03-01

    Vertically aligned nickel-cobalt layered double hydroxides (LDHs) nanosheets as electroactive materials are directly deposited on Ni foam substrate using a facile hydrothermal method. The Ni-Co LDHs nanosheets are interlaced on the substrate with an average thickness of about 20 nm. Galvanostatic charge-discharge measurement reveals that the LDHs-Ni foam binder-free electrode has an impressive specific capacitance as high as 1734 F g-1 at 6 A g-1 in 3 M KOH solution. It also shows a remarkable specific capacitance of up to 1146 F g-1 at a high current density of 30 A g-1.

  17. Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

    Directory of Open Access Journals (Sweden)

    Hongbo Y.

    2015-06-01

    Full Text Available The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

  18. Reduction of amorphous Fe(III)-hydroxide by binary microbial culture, a Moessbauer study

    Energy Technology Data Exchange (ETDEWEB)

    Chistyakova, N. I., E-mail: nchistyakova@yandex.ru; Rusakov, V. S.; Shapkin, A. A. [M.V. Lomonosov Moscow State University, Faculty of Physics (Russian Federation); Zhilina, T. N.; Zavarzina, D. G. [Russian Academy of Sciences, Winogradsky Institute of Microbiology (Russian Federation)

    2010-04-15

    Moessbauer investigations between 4.5 and 300 K of iron minerals formed during the growth of the binary culture containing two anaerobic alkaliphilic bacteria-dissimilatory iron-reducing Geoalkalibacter ferrihydriticus (strain Z-0531) and organotrophic Anaerobacillus alkalilacustre (strain Z- 0521), have been carried out. Mannitol (2 g/l) as the sole substrate with amorphous Fe(III) hydroxide at final concentration 10 or 100 mM were added to the mineral medium. The formation of siderite and probable magnetite or a mixture of magnetite and maghemite were observed.

  19. Anion-exchange membranes derived from quaternized polysulfone and exfoliated layered double hydroxide for fuel cells

    Science.gov (United States)

    Liu, Wan; Liang, Na; Peng, Pai; Qu, Rong; Chen, Dongzhi; Zhang, Hongwei

    2017-02-01

    Layered double hydroxides (LDH) are prepared by controlling urea assisted homogeneous precipitation conditions. Morphology and crystallinity of LDHs are confirmed by X-ray diffraction and scanning electron microscope. After LDHs are incorporated into quaternized polysulfone membranes, transmission electron microscope is used to observe the exfoliated morphology of LDH sheets in the membranes. The properties of the nanocomposite membranes, including water uptake, swelling ratio, mechanical property and ionic conductivity are investigated. The nanocomposite membrane containing 5% LDH sheets shows more balanced performances, exhibiting an ionic conductivity of 2.36×10-2 S cm-1 at 60 °C.

  20. Cobalt hydroxide nanoflakes and their application as supercapacitors and oxygen evolution catalysts

    Science.gov (United States)

    Rovetta, A. A. S.; Browne, M. P.; Harvey, A.; Godwin, I. J.; Coleman, J. N.; Lyons, M. E. G.

    2017-09-01

    Finding alternative routes to access and store energy has become a major issue recently. Transition metal oxides have shown promising behaviour as catalysts and supercapacitors. Recently, liquid exfoliation of bulk metal oxides appears to be an effective route which provides access to two-dimensional (2D) nano-flakes, the size of which can be easily selected. These 2D materials exhibit excellent electrochemical charge storage and catalytic activity for the oxygen evolution reaction. In this study, various sized selected cobalt hydroxide nano-flake materials are fabricated by this time efficient and highly reproducible process. Subsquently, the electrochemical properties of the standard size Co(OH)2 nanoflakes were investigated. The oxide modified electrodes were prepared by spraying the metal oxide flake suspension onto a porous conductive support electrode foam, either glassy carbon or nickel. The cobalt hydroxide/nickel foam system was found to have an overpotential value at 10 mA cm-2 in 1 M NaOH as low as 280 mV and an associated redox capacitance exhibiting numerical values up to 1500 F g-1, thereby making it a viable dual use electrode.

  1. Phosphate adsorption from sewage sludge filtrate using zinc-aluminum layered double hydroxides.

    Science.gov (United States)

    Cheng, Xiang; Huang, Xinrui; Wang, Xingzu; Zhao, Bingqing; Chen, Aiyan; Sun, Dezhi

    2009-09-30

    A series of layered double hydroxides (LDHs) with different metal cations were synthesized to remove phosphate in waste sludge filtrate from a municipal wastewater treatment plant for phosphorus recovery and to help control eutrophication. The highest phosphate adsorption capacity was obtained by using Zn-Al-2-300, that is LDHs with Zn/Al molar ratio of 2 and calcined at 300 degrees C for 4h. Circumneutral and mildly alkaline waters appeared suitable for the possible application of Zn-Al LDHs due to the amphoteric nature of aluminum hydroxide. Phosphate adsorption from the sludge filtrate by the LDHs followed pseudo-second-order kinetics, and the adsorption capacity at equilibrium was determined to be approximately 50 mg P/g. Adsorption isotherms showed that phosphate uptake in this study was an endothermic process and had a good fit with a Langmuir-type model. The absorbed phosphate can be effectively desorbed (more than 80%) from LDHs particles by a 5 wt% NaOH solution. The regeneration rate of used LDHs was approximately 60% after six cycles of adsorption-desorption-regeneration.

  2. Generation of Hydrogen, Lignin and Sodium Hydroxide from Pulping Black Liquor by Electrolysis

    Directory of Open Access Journals (Sweden)

    Guangzai Nong

    2015-12-01

    Full Text Available Black liquor is generated in Kraft pulping of wood or non-wood raw material in pulp mills, and regarded as a renewable resource. The objective of this paper was to develop an effective means to remove the water pollutants by recovery of both lignin and sodium hydroxide from black liquor, based on electrolysis. The treatment of a 1000 mL of black liquor (122 g/L solid contents consumed 345.6 kJ of electric energy, and led to the generation of 30.7 g of sodium hydroxide, 0.82 g of hydrogen gas and 52.1 g of biomass solids. Therefore, the recovery ratios of elemental sodium and biomass solids are 80.4% and 76%, respectively. Treating black liquor by electrolysis is an environmentally friendly technology that can, in particular, be an alternative process in addressing the environmental issues of pulping waste liquor to the small-scale mills without black liquor recovery.

  3. Radiopacity evaluation of root canal sealers containing calcium hydroxide and MTA

    Directory of Open Access Journals (Sweden)

    Juliane Maria Guerreiro- Tanomaru

    2009-06-01

    Full Text Available The purpose of this study was to evaluate the radiopacity of root canal sealers containing calcium hydroxide and MTA (Acroseal, Sealer 26, Sealapex, Endo CPM Sealer, Epiphany and Intrafill. Five disc-shaped specimens (10 x 1 mm were fabricated from each material, according to the ISO 6876/2001 standard. After setting of the materials, radiographs were taken using occlusal film and a graduated aluminum stepwedge varying from 2 to 16 mm in thickness. The dental X-ray unit (GE1000 was set at 50 kVp, 10 mA, 18 pulses/s and distance of 33.5 cm. The radiographs were digitized and the radiopacity compared to that of the aluminum stepwedge using VIXWIN-2000 software (Gendex. The data (mmAl were analyzed statistically by ANOVA and Tukey's test at the 5% significance level. Epiphany and Intrafill presented the highest radiopacity values (8.3 mmAl and 7.5 mmAl respectively, p < 0.05 followed by Sealer 26 (6.3 mmAl, Sealapex (6.1 mmAl and Endo CPM Sealer (6 mmAl. Acroseal was the least radiopaque material (4 mmAl, p < 0.05. In conclusion, the calcium hydroxide- and MTA-containing root canal sealers had different radiopacities. However, all materials presented radiopacity values above the minimum recommended by the ISO standard.

  4. Retention of heavy metals on layered double hydroxides thin films deposited by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vlad, A., E-mail: angela.vlad@gmail.com [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Birjega, R.; Matei, A.; Luculescu, C.; Mitu, B.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Zavoianu, R.; Pavel, O.D. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest (Romania)

    2014-05-01

    Heavy metals are toxic and hazardous pollutants in the environment due to their nonbiodegradability and persistence, which can pose serious threats to living organisms. The ability of Mg–Al based layered double hydroxides (LDHs) thin films to retain heavy metals from aqueous solutions at different concentrations is a novel topic with prospects of attractive applications, such as detection of heavy metals. We report on the ability of a series of Mg–Al based layered double hydroxides thin films to detect Ni and Co cations in aqueous solutions. Uptake of heavy metals ions such as Ni{sup 2+}, Co{sup 2+} from aqueous solutions was studied as function of contact time at a standard metal ion concentration. The LDHs thin films were deposited using pulsed laser deposition (PLD). The different adsorption mechanisms were studied in connection with different heavy metals used as probe cations. X-ray diffraction, atomic force microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Fourier transform infra-red spectroscopy were the techniques used for the investigation of as deposited and after heavy metals retention thin films.

  5. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    Energy Technology Data Exchange (ETDEWEB)

    Vlad, A., E-mail: angela.vlad@gmail.com [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 76900 Bucharest-Magurele (Romania); Zavoianu, R.; Pavel, O.D. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest (Romania)

    2015-10-15

    Highlights: • PLD was successfully used to produce Mg2Al thin films from Mg–Al LDH target (Mg/Al = 2). • Well oriented LDH films were obtained for all three wavelengths of a Nd:YAG laser: 266 nm, 352 nm, 1064 nm. • Mg–Al LDH thin films obtained in this work could be suitable as adsorbent material for the detection of copper in aqueous solutions. - Abstract: Layered double hydroxides (LDHs) thin films with Mg–Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  6. Retention of heavy metals on layered double hydroxides thin films deposited by pulsed laser deposition

    Science.gov (United States)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Mitu, B.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2014-05-01

    Heavy metals are toxic and hazardous pollutants in the environment due to their nonbiodegradability and persistence, which can pose serious threats to living organisms. The ability of Mg-Al based layered double hydroxides (LDHs) thin films to retain heavy metals from aqueous solutions at different concentrations is a novel topic with prospects of attractive applications, such as detection of heavy metals. We report on the ability of a series of Mg-Al based layered double hydroxides thin films to detect Ni and Co cations in aqueous solutions. Uptake of heavy metals ions such as Ni2+, Co2+ from aqueous solutions was studied as function of contact time at a standard metal ion concentration. The LDHs thin films were deposited using pulsed laser deposition (PLD). The different adsorption mechanisms were studied in connection with different heavy metals used as probe cations. X-ray diffraction, atomic force microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, Fourier transform infra-red spectroscopy were the techniques used for the investigation of as deposited and after heavy metals retention thin films.

  7. Layered double hydroxides/polymer thin films grown by matrix assisted pulsed laser evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Birjega, R.; Matei, A.; Mitu, B.; Ionita, M.D.; Filipescu, M.; Stokker-Cheregi, F.; Luculescu, C.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest–Magurele (Romania); Zavoianu, R.; Pavel, O.D. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest (Romania); Corobea, M.C. [National R. and S. Institute for Chemistry and Petrochemistry, ICECHIM, 202 Splaiul Independentei Str., CP-35-274, 060021, Bucharest (Romania)

    2013-09-30

    Due to their highly tunable properties, layered double hydroxides (LDHs) are an emerging class of the favorably layered crystals used for the preparation of multifunctional polymer/layered crystal nanocomposites. In contrast to cationic clay materials with negatively charge layers, LDHs are the only host lattices with positively charged layers (brucite-like), with interlayer exchangeable anions and intercalated water. In this work, the deposition of thin films of Mg and Al based LDH/polymers nanocomposites by laser techniques is reported. Matrix assisted pulsed laser evaporation was the method used for thin films deposition. The Mg–Al LDHs capability to act as a host for polymers and to produce hybrid LDH/polymer films has been investigated. Polyethylene glycol with different molecular mass compositions and ethylene glycol were used as polymers. The structure and surface morphology of the deposited LDH/polymers films were examined by X-ray diffraction, Fourier transform infra-red spectroscopy, atomic force microscopy and scanning electron microscopy. - Highlights: • Hybrid composites deposited by matrix assisted pulsed laser evaporation (MAPLE). • Mg–Al layered double hydroxides (LDH) and polyethylene glycol (PEG) are used. • Mixtures of PEG1450 and LDH were deposited by MAPLE. • Deposited thin films preserve the properties of the starting material. • The film wettability can be controlled by the amount of PEG.

  8. Activation of polymer blend carbon nanofibres by alkaline hydroxides and their hydrogen storage performances

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Garcia, F.; Vilaplana-Ortego, E.; Kunowsky, M.; Linares-Solano, A. [Grupo de Materiales Carbonosos y Medio Ambiente, Departamento de Quimica Inorganica, Universidad de Alicante, E-03080 Alicante (Spain); Kimura, M. [Gun Ei Chemical Ind. Co., Ltd., Takasaki, Gunma 370-0032 (Japan); Oya, A. [Graduate School of Engineering, Gunma University, Gunma 376-8515 (Japan)

    2009-11-15

    In the present work we study the hydroxide activation (NaOH and KOH) of phenol-formaldehyde resin derived CNFs prepared by a polymer blend technique to prepare highly porous activated carbon nanofibres (ACNFs). Morphology and textural characteristics of these ACNFs were studied and their hydrogen storage capacities at 77 K (at 0.1 MPa and at high pressures up to 4 MPa) were assessed, and compared, with reported capacities of other porous carbon materials. Phenol-formaldehyde resin derived carbon fibres were successfully activated with these two alkaline hydroxides rendering highly microporous ACNFs with reasonable good activation process yields up to 47 wt.% compared to 7 wt.% yields from steam activation for similar surface areas of 1500 m{sup 2}/g or higher. These nano-sized activated carbons present interesting H{sub 2} storage capacities at 77 K which are comparable, or even higher, to other high quality microporous carbon materials. This observation is due, in part, to their nano-sized diameters allowing to enhance their packing densities to 0.71 g/cm{sup 3} and hence their resulting hydrogen storage capacities. (author)

  9. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)

    2017-04-15

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  10. [Magnesium hydroxide treatment of hyperphosphatemia in chronic hemodialysis patients with an aluminum overload].

    Science.gov (United States)

    Roujouleh, H; Lavaud, S; Toupance, O; Melin, J P; Chanard, J

    1987-01-01

    The control of hyperphosphatemia in dialysis patients is frequently achieved using aluminium hydroxide (A1(OH)3) and/or calcium carbonate (Ca CO3). However, this effect is counterbalanced by risk of aluminium intoxication and hypercalcemia. An alternative to the use of these phosphate binders is the prescription of magnesium hydroxide (Mg(OH)2) in association with a magnesium free dialysate. 19 patients with subtoxic plasma aluminium concentration received such a therapy. 9 months after starting the essay 4 patients had been excluded for digestive intolerance (3 cases) and neuro-psychic symptoms related to hypermagnesemia (1 case) after therapy with maximal doses of 6 to 12 g/d. Plasma inorganic phosphorus was decreased from 2.47 +/- 0.32 to 1.86 +/- 0.40 mmol/l (P less than 0.05) and plasma aluminium from 3.03 +/- 0.93 to 1.52 +/- 0.15 mumol/l (P less than 0.05). The results have been obtained without any significant increase in plasma and red cell magnesium levels. Metabolic alkalosis has been observed in association with the increase of ion exchange resin (sodium polystyrene sulfonate: Kayexalate) to treat progressive hyperkalemia. With the exception of possible metabolic effects occurring on a long term basis, Mg(OH)2 in association with magnesium-free dialysate seems of value to treat dialysis hyperphosphatemia.

  11. A study of thermally activated Mg–Fe layered double hydroxides as potential environmental catalysts

    Directory of Open Access Journals (Sweden)

    MILICA S. HADNAĐEV-KOSTIĆ

    2010-09-01

    Full Text Available Layered double hydroxides (LDHs and mixed oxides derived after thermal decomposition of LDHs with different Mg–Fe contents were investigated. These materials were chosen because of the possibility to tailor their various properties, such as ion-exchange capability, redox and acid–base and surface area. Layered double hydroxides, [Mg1-xFex(OH2](CO3x/2×mH2O (where x presents the content of trivalent ions, x = M(III/(M(II + M(III were synthesized using the low supersaturation precipitation method. The influence of different Mg/Fe ratios on the structure and surface properties of the LDH and derived mixed oxides was investigated in correlation to their catalytic properties in the chosen test reaction (Fischer–Tropsch synthesis. It was determined that the presence of active sites in the mixed oxides is influenced by the structural properties of the initial LDH and by the presence of additional Fe phases. Furthermore, a synthesis outside the optimal range for the synthesis of single phase LDHs leads to the formation of metastable, multiphase systems with specific characteristics and active sites.

  12. Mechanochemical synthesis of dodecyl sulfate anion (DS-) intercalated Cu-Al layered double hydroxide

    Science.gov (United States)

    Qu, Jun; He, Xiaoman; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

    2017-12-01

    Dodecyl sulfate anion (DS-) was successfully intercalated into the gallery space of Cu-Al layered double hydroxides (LDH) by a non-heating mechanochemical route, in which basic cupric carbonate (Cu2(OH)2CO3) and aluminum hydroxide (Al(OH)3) were first dry ground and then agitated in SDS solution under ambient environment. The organics modified Cu-Al LDH showed good adsorption ability toward 2,4-dichlorophenoxyacetic acid (2, 4-D). The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), CHS elemental analysis and Scanning electron microscopy (SEM). The LDH precursor prepared by ball-milling could directly react with SDS molecules forming a pure phase of DS- pillared Cu-Al LDH, which was not observed with the LDH product through the ion-exchange of DS- at room temperature. The process introduced here may be applied to manufacture other types of organic modified composites for pollutants removal and other applications.

  13. Chloride adsorption by calcined layered double hydroxides in hardened Portland cement paste

    KAUST Repository

    Yoon, Seyoon

    2014-06-01

    This study investigated the feasibility of using calcined layered double hydroxides (CLDHs) to prevent chloride-induced deterioration in reinforced concrete. CLDHs not only adsorbed chloride ions in aqueous solution with a memory effect but also had a much higher binding capacity than the original layered double hydroxides (LDHs) in the cement matrix. We investigated this adsorption in hardened cement paste in batch cultures to determine adsorption isotherms. The measured and theoretical binding capacities (153 mg g -1 and 257 mg g-1, respectively) of the CLDHs were comparable to the theoretical capacity of Friedel\\'s salt (2 mol mol-1 or 121 mg g-1), which belongs to the LDH family among cementitious phases. We simulated chloride adsorption by CLDHs through the cement matrix using the Fickian model and compared the simulation result to the X-ray fluorescence (XRF) chlorine map. Based on our results, it is proposed that the adsorption process is governed by the chloride transport through the cement matrix; this process differs from that in an aqueous solution. X-ray diffraction (XRD) analysis showed that the CLDH rebuilds the layered structure in a cementitious environment, thereby demonstrating the feasibility of applying CLDHs to the cement and concrete industries. © 2014 Published by Elsevier B.V. All rights reserved.

  14. Cobalt Iron Hydroxide as a Precious Metal-Free Bifunctional Electrocatalyst for Efficient Overall Water Splitting.

    Science.gov (United States)

    Babar, Pravin; Lokhande, Abhishek; Shin, Hyeong Ho; Pawar, Bharati; Gang, Myeng Gil; Pawar, Sambhaji; Kim, Jin Hyeok

    2018-02-01

    Highly efficient and stable electrocatalysts from inexpensive and earth-abundant elements are emerging materials in the overall water splitting process. Herein, cobalt iron hydroxide nanosheets are directly deposited on nickel foam by a simple and rapid electrodeposition method. The cobalt iron hydroxide (CoFe/NF) nanosheets not only allow good exposure of the highly active surface area but also facilitate the mass and charge transport capability. As an anode, the CoFe/NF electrocatalyst displays excellent oxygen evolution reaction catalytic activity with an overpotential of 220 mV at a current density of 10 mA cm -2 . As a cathode, it exhibits good performance in the hydrogen evolution reaction with an overpotential of 110 mV, reaching a current density of 10 mA cm -2 . When CoFe/NF electrodes are used as the anode and the cathode for water splitting, a low cell voltage of 1.64 V at 10 mA cm -2 and excellent stability for 50 h are observed. The present work demonstrates a possible pathway to develop a highly active and durable substitute for noble metal electrocatalysts for overall water splitting. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Shape and size control of nano dispersed Mg/Al layered double hydroxide.

    Science.gov (United States)

    Panda, H S; Srivastava, R; Bahadur, D

    2008-08-01

    Controlling the shape and size of the layered inorganic-organic hybrid particles is a challenge with conventional methods of synthesis. The co-precipitation method has been modified to synthesize Mg/Al Layered double hydroxide by controlling the particle growth using ultrasonic wave at the time of nucleation. In this project, magnesium and aluminum ions were considered as model systems with carbonate anion as intercalating agent. The resulting particles are compared with those of LDHs produced by conventional co-precipitation method at constant pH. Powder X-ray diffraction confirmed formation of the layered double hydroxide phases having crystallite size 19-20 nm in both 'a' and 'c' crystallographic directions. Transmission electron microscope and dynamic light scattering revealed nano disperse hexagonal platelets with narrow size distribution and average size was around 48 nm. The modified method reduces the particle size, increases the surface charge, narrows down the size distribution and also reduces the aspect ratio of the particles. Therefore, it is suggested that low amplitude ultrasonic wave prevents the aggregation of the nuclei, thus restricting the particle growth and results in uniform size particles.

  16. The Effect of Sodium Hydroxide on Drag Reduction using a Biopolymer.

    Directory of Open Access Journals (Sweden)

    Singh Harvin Kaur A/P Gurchran

    2014-07-01

    Full Text Available Drag reduction is observed as reduced frictional pressure losses under turbulent flow conditions and hence, substantially increases the flowrate of the fluid. Practical application includes water flooding system, pipeline transport and drainage system. Drag reduction agent, such as polymers, can be introduced to increase the flowrate of water flowing, reducing the water accumulation in the system and subsequently lesser possibility of heavy flooding. Currently used polymer as drag reduction agents is carboxymethylcellulose, to name one. This is a synthetic polymer which will seep into the ground and further harm our environment in excessive use of accumulation. A more environmentally-friendly drag reduction agent, such as the polymer derived from natural sources or biopolymer, is then required for such purpose. As opposed to the synthetic polymers, the potential of biopolymers as drag reduction agents, especially those derived from a local plant source, are not extensively explored. The drag reduction of a polymer produced from a local plant source within the turbulent regime will be explored and assessed in this study using a rheometer where a reduced a torque produced can be perceived as a reduction of drag. The cellulose powder was converted to carboxymethylcellulose (CMC by etherification process using sodium monochloroacetate and sodium hydroxide. The carboxymethylation reaction then was optimized against concentration of NaOH. The research is structured to focus on producing the biopolymer and also assess the drag reduction ability of the biopolymer produced against concentration of sodium hydroxide.

  17. Pilot-scale production of biodiesel from waste fats and oils using tetramethylammonium hydroxide.

    Science.gov (United States)

    Šánek, Lubomír; Pecha, Jiří; Kolomazník, Karel; Bařinová, Michaela

    2016-02-01

    Annually, a great amount of waste fats and oils not suitable for human consumption or which cannot be further treated are produced around the world. A potential way of utilizing this low-cost feedstock is its conversion into biodiesel. The majority of biodiesel production processes today are based on the utilization of inorganic alkali catalysts. However, it has been proved that an organic base - tetramethylammonium hydroxide - can be used as a very efficient transesterification catalyst. Furthermore, it can be employed for the esterification of free fatty acids - reducing even high free fatty acid contents to the required level in just one step. The work presented herein, is focused on biodiesel production from waste frying oils and animal fats using tetramethylammonium hydroxide at the pilot-plant level. The results showed that the process performance in the pilot unit - using methanol and TMAH as a catalyst, is comparable to the laboratory procedure, even when the biodiesel is produced from waste vegetable oils or animal fats with high free fatty acid content. The reaction conditions were set at: 1.5% w/w of TMAH, reaction temperature 65°C, the feedstock to methanol molar ratio to 1:6, and the reaction time to 120min. The conversion of triglycerides to FAME was approximately 98%. The cloud point of the biodiesel obtained from waste animal fat was also determined. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Accidental contamination of a German town's drinking water with sodium hydroxide.

    Science.gov (United States)

    Lendowski, Luba; Färber, Harald; Holy, Andreas; Darius, Anke; Ehrich, Bernd; Wippermann, Christine; Küfner, Bernd; Exner, Martin

    2015-05-01

    Case report of a very serious drinking water incident putting up to 50,000 inhabitants of a town near Bonn in North Rhine-Westphalia, Germany at risk. A concentrated solution of highly alkaline water by sodium hydroxide was accidentally washed into the town's drinking water at a pumping station and increased the pH-value of the water to 12. Residents who came into contact with the contaminated water immediately had a toxic reaction. The incident was detected by complaints from customers and after that was stopped within several hours. The pipes were flushed and the customers were warned not to use the water till the all clear. After this immediate management there was an investigation and the cause of the incident was detected as an accidental release of accumulated sodium hydroxide (NaOH) solution. The lack of a network alarm system and the automatic cut-off mechanisms as deficiencies in the design of the station were rectified by the water company immediately after the incident. Copyright © 2015 Elsevier GmbH. All rights reserved.

  19. Advanced oxidation of rhodamine B with hydrogen peroxide over ZnCr layered double hydroxide catalysts

    Directory of Open Access Journals (Sweden)

    Nguyen Tien Thao

    2017-09-01

    Full Text Available Zn/Cr layered zinc hydroxide materials with different molar ratios of Cr/Zn have been synthesized through the coprecipitation method at pH of 9.0–9.5. At high Cr/Zn molar ratios of 0.5/1–1/3, the materials possess some layered structure with carbonate anions between the interlayer galleries. The catalysts present uniform particle sizes and quite high surface area. An isomorphous substitution of Zn2+ by Cr3+ in the brucite-like sheets makes the layered Cr-doped zinc hydroxides potential catalysts for efficient oxidation of rhodamine B with H2O2 solution. The experimental results indicated that the intra-lattice Cr3+ ions are more active than Cr2O3 components in the oxidative removal of rhodamine B. The degradation efficiency is dependent on the intra lattice Cr3+ contents and reaction variables. The Cr/Zn LDH gave a high decolorization (99% of rhodamine B at near neutral pH and room temperature.

  20. Organo-layered double hydroxides composite thin films deposited by laser techniques

    Energy Technology Data Exchange (ETDEWEB)

    Birjega, R. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Vlad, A., E-mail: angela.vlad@gmail.com [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Matei, A.; Dumitru, M.; Stokker-Cheregi, F.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Zavoianu, R. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest 030018 (Romania); Raditoiu, V.; Corobea, M.C. [National R.& D. Institute for Chemistry and Petrochemistry, ICECHIM, 202 Splaiul Independentei Str., CP-35-274, 060021 Bucharest (Romania)

    2016-06-30

    Highlights: • PLD and MAPLE was successfully used to produce organo-layered double hydroxides. • The organic anions (dodecyl sulfate-DS) were intercalated in co-precipitation step. • Zn2.5Al-LDH (Zn/Al = 2.5) and Zn2.5Al-DS thin films obtained in this work could be suitable for further applications as hydrophobic surfaces. - Abstract: We used laser techniques to create hydrophobic thin films of layered double hydroxides (LDHs) and organo-modified LDHs. A LDH based on Zn-Al with Zn{sup 2+}/Al{sup 3+} ratio of 2.5 was used as host material, while dodecyl sulfate (DS), which is an organic surfactant, acted as guest material. Pulsed laser deposition (PLD) and matrix assisted pulsed laser evaporation (MAPLE) were employed for the growth of the films. The organic anions were intercalated in co-precipitation step. The powders were subsequently used either as materials for MAPLE, or they were pressed and used as targets for PLD. The surface topography of the thin films was investigated by atomic force microscopy (AFM), the crystallographic structure of the powders and films was checked by X-ray diffraction. FTIR spectroscopy was used to evidence DS interlayer intercalation, both for powders and the derived films. Contact angle measurements were performed in order to establish the wettability properties of the as-prepared thin films, in view of functionalization applications as hydrophobic surfaces, owing to the effect of DS intercalation.

  1. Adsorption of phosphonate antiscalant from reverse osmosis membrane concentrate onto granular ferric hydroxide.

    Science.gov (United States)

    Boels, Luciaan; Keesman, Karel J; Witkamp, Geert-Jan

    2012-09-04

    Adsorptive removal of antiscalants offers a promising way to improve current reverse osmosis (RO) concentrate treatment processes and enables the reuse of the antiscalant in the RO desalination process. This work investigates the adsorption and desorption of the phosphonate antiscalant nitrilotris(methylenephosphonic acid) (NTMP) from RO membrane concentrate onto granular ferric hydroxide (GFH), a material that consists predominantly of akaganéite. The kinetics of the adsorption of NTMP onto GFH was predicted fairly well with two models that consider either combined film-pore or combined film-surface diffusion as the main mechanism for mass transport. It is also demonstrated that NTMP is preferentially adsorbed over sulfate by GFH at pH 7.85. The presence of calcium causes a transformation in the equilibrium adsorption isotherm from a Langmuir type to a Freundlich type with much higher adsorption capacities. Furthermore, calcium also increases the rate of adsorption substantially. GFH is reusable after regeneration with sodium hydroxide solution, indicating that NTMP can be potentially recovered from the RO concentrate. This work shows that GFH is a promising adsorbent for the removal and recovery of NTMP antiscalant from RO membrane concentrates.

  2. Regeneration of Waste Edible Oil by the Use of Virgin and Calcined Magnesium Hydroxide as Adsorbents.

    Science.gov (United States)

    Ogata, Fumihiko; Kawasaki, Naohito

    2016-01-01

    In this study, we prepared virgin (S, L) and calcined (S-380, S-1000, L-380, L-1000) magnesium hydroxide for regeneration of waste edible oil. Deterioration of soybean oil, rapeseed oil, and olive oil was achieved by heat and aeration treatment. The properties of the different adsorbents were investigated using specific surface area measurements, scanning electron microscopy, X-ray diffraction analysis, thermogravimetric-differential thermal analysis, and surface pH measurement. Moreover, the relationship between the changes in acid value (AV) and carbonyl value (CV) and the adsorbent properties were evaluated. The specific surface areas of S-380 and L-380 were greater than that of other adsorbents. In addition, the XRD results show that S-380 and L-380 contain both magnesium hydroxide and magnesium oxide structures. The decreases in AV and CV using S-380 and L-380 were greater than achieved using other adsorbents. The correlation coefficients between the decrease in AV and CV and specific surface area were 0.947 for soybean oil, 0.649 for rapeseed oil, and 0.773 for olive oil, respectively. The results obtained in this study suggest that a physical property of the adsorbent, namely specific surface area, was primarily responsible for the observed decreases in AV and CV. Overall, the results suggest that S-380 and L-380 are useful for the regeneration of waste edible oil.

  3. Organo/layered double hydroxide nanohybrids used to remove non ionic pesticides.

    Science.gov (United States)

    Chaara, D; Bruna, F; Ulibarri, M A; Draoui, K; Barriga, C; Pavlovic, I

    2011-11-30

    The preparation and characterization of organo/layered double hydroxide nanohybrids with dodecylsulfate and sebacate as interlayer anion were studied in detail. The aim of the modification of the layered double hydroxides (LDHs) was to change the hydrophilic character of the interlayer to hydrophobic to improve the ability of the nanohybrids to adsorb non-ionic pesticides such as alachlor and metolachlor from water. Adsorption tests were conducted on organo/LDHs using variable pH values, contact times and initial pesticide concentrations (adsorption isotherms) in order to identify the optimum conditions for the intended purpose. Adsorbents and adsorption products were characterized several physicochemical techniques. The adsorption test showed that a noticeable increase of the adsorption of the non-ionic herbicides was produced. Based on the results, the organo/LDHs could be good adsorbents to remove alachlor and metolachlor from water. Different organo/LDHs complexes were prepared by a mechanical mixture and by adsorption. The results show that HTSEB-based complex displays controlled release properties that reduce metolachlor leaching in soil columns compared to a technical product and the other formulations. The release was dependent on the nature of the adsorbent used to prepare the complexes. Thus, it can be concluded that organo/LDHs might act as suitable supports for the design of pesticide slow release formulations with the aim of reducing the adverse effects derived from rapid transport losses of the chemical once applied to soils. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Evaluation of preservative effectiveness of gallic acid derivatives in aluminum hydroxide gel-USP

    Directory of Open Access Journals (Sweden)

    Anurag Khatkar

    2013-01-01

    Full Text Available Background: Preservatives are added to most of the pharmaceutical preparations to prevent them from deterioration throughout their shelf life. Literature reveals that the common synthetic preservatives have many limitations, such as development of microbial resistance (in due course of time and several serious side-effects. Aim: The aim of this study is to find out new preservatives synthesized from natural sources, which may have better efficiency than the existing synthetic preservatives. The derivatives of naturally occurring gallic acid were subjected for their preservative efficacy study. Their preservative efficiency was evaluated and compared with the standard parabens. Materials and Methods: The selected amide, anilide and ester derivatives of gallic acid were subjected to preservative efficacy testing in an official antacid preparation, {aluminum hydroxide gel-USP (United States Pharmacopoeia} against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans, and Aspergillus niger as representative challenging microorganisms as per USP 2004 guidelines. Results: The selected derivatives were found to be effective against all selected strains and showed preservative efficacy comparable to that of standard and even better in case E. coli, C. albicans and A. niger. The 8-hydroxy quinoline ester derivative showed better preservative efficacy than standard as well as other derivatives. Conclusion: The newly synthesized gallic acid preservatives were found to be effective in the proposed pharmaceutical preparation (Aluminium Hydroxide Gel - USP. Also, the synthesized preservatives have shown comparative and even better efficacy than the existing parabens and hence they have potential for use in pharmaceutical preparations.

  5. Evaluation of preservative effectiveness of p-coumaric acid derivatives in aluminium hydroxide gel-USP

    Directory of Open Access Journals (Sweden)

    Anurag Khatkar

    2013-01-01

    Full Text Available Background: Deterioration of pharmaceutical preparations due to growth of microorganisms is a great challenge and need of preservation becomes very important. Literature reports about various problems associated with the existing synthetic preservatives such as development of microbial resistance (in due course of time and several serious side effects. Aim: The aim of the present study is to find out new preservatives synthesized from natural sources, which may have better efficiency than the existing synthetic preservatives. The derivatives of naturally occurring p-coumaric acid were subjected for their preservative efficacy study. Their preservative efficiency was evaluated and compared with the standard parabens. Materials and Methods: The selected amide, anilide and ester derivatives of p-coumaric acid were subjected to preservative efficacy testing in an official antacid preparation, (aluminium hydroxide gel-USP against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans and Aspergillus niger as representative challenging microorganisms as per USP 2004 guidelines. Results: The selected derivatives were found to be effective against all selected strains and showed preservative efficacy comparable to that of standard and even better in case E. coli, C. albicans and A. niger. The 8-hydroxy quinoline ester derivative showed better preservative efficacy than standard as well as other derivatives. Conclusion: The newly synthesized p- coumaric acid preservatives were found to be effective in the proposed pharmaceutical preparation (Aluminium Hydroxide Gel - USP. Also, the synthesized preservatives have shown comparative and even better efficacy than the existing parabens and hence they have potential for use in pharmaceutical preparations.

  6. Defluoridation of groundwater by calcined Mg/Al layered double hydroxide

    Directory of Open Access Journals (Sweden)

    A. Elhalil

    2016-03-01

    Full Text Available The present study evaluated calcined Mg/Al layered double hydroxide (CLDH availability for the removal of fluoride from local groundwaters. The Mg/Al layered double hydroxide (LDH was synthesized by co-precipitation method and characterized by XRD, FT-IR and TGA-TDA analyses. Batch defluoridation experiments were performed under various conditions such as calcination, solution pH, contact time, temperature, material dosage and reuse. Experimental results indicate that fluoride removal strongly increased after calcination of the LDH up to 600 °C. The maximum fluoride removal was obtained at solution pH of 6.85. Kinetics of fluoride removal followed the pseudo-second order kinetic model. The rise in solution temperature strongly enhances the removal efficiency. The adsorption mechanism involved surface adsorption, ion exchange interaction and original LDH structure reconstruction by rehydration of mixed metal oxides and concomitant intercalation of fluoride ions into the interlayer region. The optimum dosages required to meet the national standard for drinking water quality were found to be 0.29 and 0.8 g/L, respectively, for Bejaad and Settat goundwaters. A decrease in the fluoride uptake with increasing the number of regeneration cycles was observed.

  7. Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate–zinc layered hydroxide nanohybrid

    Energy Technology Data Exchange (ETDEWEB)

    Bashi, Abbas M., E-mail: abbasmatrood@yahoo.com [Department of Medical Analysis, Faculty of Medical Science, Karbala University (Iraq); Hussein, Mohd Zobir; Zainal, Zulkarnain [Chemistry Department Faculty of Science-UPM (Malaysia); Tichit, Didier [Institut Charles Gerhardt UMR 5253 CNRS/UM2/ENSCM/UM1, Matériaux Avancés pour la Catalyse et la Santé, 8 rue Ecole Normale, 34296 Montpellier Cedex 5 (France)

    2013-07-15

    Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic–inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D–ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model. - Graphical abstract: The phenomenon indicates that the optical energy gap is enlarged with the increase of molar concentrations in 2,4-dichlorophenoxy acetate anion content into ZnO to create a ZLH–24D nanohybrid. - Highlights: • Nanohybrid was synthesized from 2,4-dichlorophenoxy acetate with-Zinc LHD, using wet chemistry. • Characterized using SEM, TEM, EDX, FTIR, XRD and TGA. • Ribbon-shaped 24D–Zn-layered hydroxide nanoparticles with (003) diffractions of 2.5 nm phase were synthesized.

  8. Evidence of pulpotomy in primary teeth comparing MTA, calcium hydroxide, ferric sulphate, and electrosurgery with formocresol.

    Science.gov (United States)

    Stringhini Junior, E; Vitcel, M E B; Oliveira, L B

    2015-08-01

    The aim of this study was to evaluate the scientific evidence of pulpotomy in primary teeth comparing mineral troxide aggregate (MTA), calcium hydroxide, ferric sulphate, and electrosurgery with formocresol. A systematic search using key words was conducted using seven databases up to December 10, 2013. Clinical articles in English, Portuguese and Spanish were selected, which were in accordance with the inclusion and exclusion criteria and the research objective of comparing whether pulpotomy performed with formocresol in primary teeth is more effective than other medicaments or techniques. Out of the 12,515 publication initially identified, 30 clinical articles were included in the systematic review and analysed by four meta-analyses. The success rate of MTA (94.6 %) was higher than that of formocresol (87.4 %), with a statistically significant difference (OR = 0.39; 95 % CI = 0.25-0.62). Formocresol pulpotomy success was not statistically different from ferric sulphate or electrosurgery. MTA was clinically and radiographically superior to formocresol for pulpotomy of primary teeth. The other alternatives to formocresol such as electrosurgery and ferric sulphate can be used instead of formocresol since they showed success similar to formocresol. In addition, there is no evidence to support calcium hydroxide for pulpotomies in primary teeth.

  9. Mineralogy of C-S-H belite hydrates incorporating Zn-Al-Ti layered double hydroxides

    Directory of Open Access Journals (Sweden)

    Amor F.

    2018-01-01

    Full Text Available Recently, the belitic cements with low alite content were the subject of several research works which aimed to replace the Ordinary Portland Clinker (OPC for ecological reasons (reduction of CO2 emissions, so to understand the reactivity of this cement, the hydration study of the C2S “dicalcium silicate” phase is primordial research step. As well for a clean environment, the TiO2 photocatalyst has been extensively applied in the science of building materials because of its ability to degrade the cement surface pollutants. New photocatalyst based layered double hydroxides (LDH associated with zinc, aluminium and TiO2 was introduced to increase the compatibility with mortars. The present work is subjected to investigate the effect of the layered double hydroxides on the hydration of C2S in following the evolution of hydration by X-ray diffraction at 2, 7, 28 and 90 days and analyzing the calcium/silicon ratio of different formed hydrates.

  10. Synthesis of Platinum-Nickel Hydroxide Nanocomposites for Electrocatalytic Reduction of Water

    KAUST Repository

    Wang, Lei

    2016-11-25

    Water electrolysis represents a promising solution for storage of renewable but intermittent electrical energy in hydrogen molecules. This technology is however challenged by the lack of efficient electrocatalysts for the hydrogen and oxygen evolution reactions. Here we report on the synthesis of platinum-nickel hydroxide nanocomposites and their electrocatalytic applications for water reduction. An in situ reduction strategy taking advantage of the Ni(II)/Ni(III) redox has been developed to enable and regulate the epitaxial growth of Pt nanocrystals on single-layer Ni(OH)2 nanosheets. The obtained nanocomposites (denoted as Pt@2D-Ni(OH)2) exhibit an improvement factor of 5 in catalytic activity and a reduction of up to 130 mV in overpotential compared to Pt for the hydrogen evolution reaction (HER). A combination of electron microscopy/spectroscopy characterization, electrochemical studies and density functional calculations was employed to uncover the structures of the metal-hydroxide interface and understand the mechanisms of catalytic enhancement.

  11. Rate capability improvement of Co-Ni double hydroxides integrated in cathodically partially exfoliated graphite

    Science.gov (United States)

    Cai, Xiang; Song, Yu; Sun, Zhen; Guo, Di; Liu, Xiao-Xia

    2017-10-01

    In-situ growing of energy storage materials on graphene-based substrates/current collectors with low defect is a good way to boost electron transport and so enhance rate capability for the obtained electrode. Herein, high-quality graphene-like nanopetals are partially exfoliated from graphite foil (GF) through a facile and fast cathodic process. Three-dimensional porous structure is established for the afforded cathodically-exfoliated graphite foil (CEG), with many graphene-like nanopetals vertically anchoring on the graphite substrate. A hierarchical structure is constructed by the following electrochemical growth of Co-Ni double hydroxide nanopetals on the graphene atop CEG. The double hydroxide in the obtained electrode with the optimized Co2+/Ni2+ molar ratio, Co0.75Ni0.25(OH)2-CEG, displays much improved rate capability and so can deliver a high specific capacitance of 1460 F g-1 at an ultra-high current density of 100 A g-1. An asymmetric device is assembled by using Co0.75Ni0.25(OH)2-CEG as cathode, which demonstrates a high energy density of 31.6 Wh kg-1 at an ultra-high power density of 21.5 kW kg-1, showing the potential of the hierarchical composite electrode for high power application. The device also displays good stability, it can retain more than 90% of its capacitance after 10000 galvanostatic charge-discharge cycles.

  12. A prospective, open, comparative study of 5% potassium hydroxide solution versus cryotherapy in the treatment of genital warts in men*

    Science.gov (United States)

    Camargo, Caio Lamunier de Abreu; Belda, Walter; Fagundes, Luiz Jorge; Romiti, Ricardo

    2014-01-01

    BACKGROUND Genital warts are caused by human papillomavirus infection and represent one of the most common sexually transmitted diseases. Many infections are transient but the virus may recur, persist, or become latent. To date, there is no effective antiviral treatment to eliminate HPV infection and most therapies are aimed at the destruction of visible lesions. Potassium hydroxide is a strong alkali that has been shown to be safe and effective for the treatment of genital warts and molluscum contagiosum. Cryotherapy is considered one of the most established treatments for genital warts. No comparative trials have been reported to date on the use of potassium hydroxide for genital warts. OBJECTIVE A prospective, open-label, randomized clinical trial was conducted to compare topical potassium hydroxide versus cryotherapy in the treatment of genital warts affecting immunocompetent, sexually active men. METHODS Over a period of 10 months, 48 patients were enrolled. They were randomly divided into two groups and selected on an alternative basis for either potassium hydroxide therapy or cryotherapy. While response to therapy did not differ substantially between both treatment modalities, side effects such as local pain and post-treatment hypopigmentation were considerably more prevalent in the groups treated using cryotherapy. RESULT In our study, potassium hydroxide therapy proved to be at least as effective as cryotherapy and offered the benefit of a better safety profile. CONCLUSION Topical 5% potassium hydroxide presents an effective, safe, and low-cost treatment modality for genital warts in men and should be included in the spectrum of therapies for genital warts. PMID:24770498

  13. Preparation of poly(ethylene terephthalate/layered double hydroxide nanocomposites by in-situ polymerization and their thermal property

    Directory of Open Access Journals (Sweden)

    Q. Jiao

    2012-06-01

    Full Text Available Terephthalate (TA intercalated layered double hydroxides (LDHs were synthesized using hydroxides as raw materials, and poly(ethylene terephthalate (PET/LDH nanocomposites with different contents of TA intercalated LDHs were prepared by in-situ polymerization. The structure, morphology and thermal property of PET/LDH nanocomposites were investigated. The TA intercalated LDHs were partially exfoliated and well dispersed in PET matrix. The PET/LDH nanocomposites exhibit enhanced thermal stability relative to pure PET, confirmed by the thermogravimetric analysis results. The results of differential scanning calorimetry suggest that LDH nanoparticles could effectively promote the nucleation and crystallization of PET.

  14. The application of layered double hydroxide clay (LDH)-poly(lactide-co-glycolic acid) (PLGA) film composites for the controlled release of antibiotics

    DEFF Research Database (Denmark)

    Chakraborti, Michelle; Jackson, John K.; Plackett, David

    2012-01-01

    bone cement, used in orthopedics, release very little drug. The purpose of this study was to investigate the use of nanoparticulates composed of layered double hydroxide clays to bind various antibiotics and release them in a controlled manner. Mg–Al (carbonate) layered double hydroxides were...

  15. [Efficacy of sodium hydroxide at 2.5 %, chlorhexidine gluconate at 0.5 % and calcium hydroxide against Candida albicans].

    Science.gov (United States)

    Ndiaye, D; Diongue, K; Bane, K; Seck, A; Niang, S O; Lèye Benoist, F; Ndiaye, D; Touré, B

    2016-12-01

    Endodontic flora is dominated in the apical part of the channels by strict anaerobic and some facultative anaerobic bacteria but also by Candida yeasts, especially Candida albicans species that are involved in the maintenance and persistence of endodontic infections. Their elimination of the canal system in practice by chemo-mechanical methods of disinfection is not always guaranteed. Thus, this in vitro study was performed to determine the sensitivity of C. albicans with sodium hypochlorite (NaOCl) dosed at 2.5 %, the chlorhexidine digluconate 0.5 % and calcium hydroxide used in inter-session medication. The diffusion method was used initially to test the sensitivity of C. albicans strains with the above products. Then a dilution technique has allowed us to determine the minimum inhibitory concentration of these active products on C. albicans. Strains from infected pulp teeth of patients showed a sensitivity of C. albicans to sodium hypochlorite to a minimum inhibitory concentration less than 70μg/mL and 30μg/mL for chlorhexidine. This study demonstrated a sensitivity of C. albicans to sodium hypochlorite and chlorhexidine. Copyright © 2016. Published by Elsevier Masson SAS.

  16. Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal.

    Science.gov (United States)

    Balto, Khaled A

    2007-01-01

    Searches of Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, six thesis databases (Networked Digital Library of Theses and Dissertations, Proquest Digital Dissertations, OAIster, Index to Theses, Australian Digital Thesis program and Dissertation.com) and one conference report database (BIOSIS Previews) were undertaken. There were no language restrictions. Studies were included in which participants had a noncontributory medical history, presented with mature teeth and radiographic evidence of periapical bone loss (as an indication of pre-operative canal infection), whose selected root canals had not previously received any endodontic treatment, and who had undergone nonsurgical root canal treatment during the study in which calcium hydroxide had also been used to seal in the canals. In addition, it was required that microbiological sampling had been undertaken during the course of treatment, before canal preparation, after canal preparation and after canal medication. Aerobic and anaerobic culturing techniques were performed on all samples. The treatment outcomes were stated in terms of positive and negative canal cultures. All data were extracted in the same manner using a standardised data extraction sheet. Between-study heterogeneity was assessed using the standard chi-squared test or Q-statistic. The principal measure of treatment effect (antibacterial efficacy) was risk difference, which is normally defined as the risk in the experimental group minus risk in the control group. For the purpose of this study, it is given as the difference in the proportion of bacteria-positive cultures pre- and post-medication. Out of the eight studies (257 cases) included, one study used a small control group (in which canals were left empty, and no intracanal medicament was used between appointments). The other seven studies simply compared the frequency of positive cultures before and after calcium hydroxide medication. Six studies demonstrated a

  17. Antimicrobial Activity and Physicochemical Properties of Calcium Hydroxide Pastes Used as Intracanal Medication.

    Science.gov (United States)

    Zancan, Rafaela Fernandes; Vivan, Rodrigo Ricci; Milanda Lopes, Marcelo Ribeiro; Weckwerth, Paulo Henrique; de Andrade, Flaviana Bombarda; Ponce, José Burgos; Duarte, Marco Antonio Hungaro

    2016-12-01

    The aim of the present study was to evaluate the pH, calcium release, solubility, and antimicrobial action against biofilms of calcium hydroxide + saline solution, Calen (SS White Artigos Dentários Ltd, Rio de Janeiro, Brazil) (CH/P), Calen camphorated paramonochlorophenol (CMCP) (CH/CMPC), and calcium hydroxide + chlorhexidine (CH/CHX) pastes. The pH of the pastes was determined with a calibrated pH meter placed in direct contact with each paste. The root canals of acrylic teeth (N = 10) were filled with the previously mentioned intracanal dressings and immersed in ultrapure water to measure hydroxyl (pH meter) and calcium ion release (atomic absorption spectrophotometer) at time intervals of 3, 7, 15, and 30 days. To assess solubility, the root canals of acrylic teeth (N = 10) were filled with the previously mentioned pastes and scanned by micro-computed tomographic imaging before (initial) and after 7, 15, and 30 days of immersion in ultrapure water. The solubility of each specimen was the difference between the initial and final volume scanning. For antimicrobial analysis, monospecies and dual-species biofilms were in vitro induced on dentin blocks (N = 20). Afterward, they were treated with the pastes for 7 days. Live/dead dye and a confocal microscope were used to measure the percentage of living cells. Data were statistically compared (P < .05). The highest OH - ion release values were found in 3 and 30 days. Ca 2+ releases were greater in CH/CMCP. CH/P and CH/CMCP showed a higher percentage of volume loss values. CH/CHX presented the greatest antimicrobial action. CH/P and CH/CMPC showed higher solubility values in the period analyzed. Seven days of contact may be insufficient for calcium hydroxide + saline solution, CH/P, and CH/CMCP pastes to kill bacterial cells in the biofilms studied. Chlorhexidine added to CH favored greater effectiveness against the previously mentioned bacterial biofilms. Copyright © 2016 American Association of

  18. Nitrogen doping in atomic layer deposition grown titanium dioxide films by using ammonium hydroxide

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, M.-L., E-mail: marja-leena.kaariainen@lut.fi; Cameron, D.C.

    2012-12-30

    Titanium dioxide films have been created by atomic layer deposition using titanium chloride as the metal source and a solution of ammonium hydroxide in water as oxidant. Ammonium hydroxide has been used as a source of nitrogen for doping and three thickness series have been deposited at 350 Degree-Sign C. A 15 nm anatase dominated film was found to possess the highest photocatalytic activity in all film series. Furthermore almost three times better photocatalytic activity was discovered in the doped series compared to undoped films. The doped films also had lower resistivity. The results from X-ray photoemission spectroscopy showed evidence for interstitial nitrogen in the titanium dioxide structure. Besides, there was a minor red shift observable in the thickest samples. In addition the film conductivity was discovered to increase with the feeding pressure of ammonium hydroxide in the oxidant precursor. This may indicate that nitrogen doping has caused the decrease in the resistivity and therefore has an impact as an enhanced photocatalytic activity. The hot probe test showed that all the anatase or anatase dominant films were p-type and all the rutile dominant films were n-type. The best photocatalytic activity was shown by anatase-dominant films containing a small amount of rutile. It may be that p-n-junctions are formed between p-type anatase and n-type rutile which cause carrier separation and slow down the recombination rate. The combination of nitrogen doping and p-n junction formation results in superior photocatalytic performance. - Highlights: Black-Right-Pointing-Pointer We found all N-doped and undoped anatase dominating films p-type. Black-Right-Pointing-Pointer We found all N-doped and undoped rutile dominating films n-type. Black-Right-Pointing-Pointer We propose that p-n junctions are formed in anatase-rutile mixture films. Black-Right-Pointing-Pointer We found that low level N-doping has increased TiO{sub 2} conductivity. Black

  19. Hupresin Retains Binding Capacity for Butyrylcholinesterase and Acetylcholinesterase after Sanitation with Sodium Hydroxide

    Directory of Open Access Journals (Sweden)

    Seda Onder

    2017-10-01

    Full Text Available Hupresin is a new affinity resin that binds butyrylcholinesterase (BChE in human plasma and acetylcholinesterase (AChE solubilized from red blood cells (RBC. Hupresin is available from the CHEMFORASE company. BChE in human plasma binds to Hupresin and is released with 0.1 M trimethylammonium bromide (TMA with full activity and 10–15% purity. BChE immunopurified from plasma by binding to immobilized monoclonal beads has fewer contaminating proteins than the one-step Hupresin-purified BChE. However, when affinity chromatography on Hupresin follows ion exchange chromatography at pH 4.5, BChE is 99% pure. The membrane bound AChE, solubilized from human RBC with 0.6% Triton X-100, binds to Hupresin and remains bound during washing with sodium chloride. Human AChE is not released in significant quantities with non-denaturing solvents, but is recovered in 1% trifluoroacetic acid. The denatured, partially purified AChE is useful for detecting exposure to nerve agents by mass spectrometry. Our goal was to determine whether Hupresin retains binding capacity for BChE and AChE after Hupresin is washed with 0.1 M NaOH. A 2 mL column of Hupresin equilibrated in 20 mM TrisCl pH 7.5 was used in seven consecutive trials to measure binding and recovery of BChE from 100 mL human plasma. Between each trial the Hupresin was washed with 10 column volumes of 0.1 M sodium hydroxide. A similar trial was conducted with red blood cell AChE in 0.6% Triton X-100. It was found that the binding capacity for BChE and AChE was unaffected by washing Hupresin with 0.1 M sodium hydroxide. Hupresin could be washed with sodium hydroxide at least seven times without losing binding capacity.

  20. Removal of oxyanions from synthetic wastewater via carbonation process of calcium hydroxide: Applied and fundamental aspects

    Energy Technology Data Exchange (ETDEWEB)

    Montes-Hernandez, G., E-mail: German.MONTES-HERNANDEZ@obs.ujf-grenoble.fr [LGCA, University Joseph Fourier, Observatoire des Sciences de l' Univers de Grenoble and CNRS, BP 53 X, 38042 Grenoble Cedex 9 (France); LPG, University Joseph Fourier, Observatoire des Sciences de l' Univers de Grenoble and CNRS, BP 53 X, 38042 Grenoble Cedex 9 (France); Concha-Lozano, N. [LGCA, University Joseph Fourier, Observatoire des Sciences de l' Univers de Grenoble and CNRS, BP 53 X, 38042 Grenoble Cedex 9 (France); Renard, F. [LGCA, University Joseph Fourier, Observatoire des Sciences de l' Univers de Grenoble and CNRS, BP 53 X, 38042 Grenoble Cedex 9 (France); Physics of Geological Processes, University of Oslo (Norway); Quirico, E. [LPG, University Joseph Fourier, Observatoire des Sciences de l' Univers de Grenoble and CNRS, BP 53 X, 38042 Grenoble Cedex 9 (France)

    2009-07-30

    Removal of oxyanions (selenite, selenate, arsenate, phosphate and nitrate) during calcite formation was experimentally studied using aqueous carbonation of calcium hydroxide under moderate pressure (P{sub CO2} {approx_equal} 20 bar) and temperature (30 {sup o}C). The effects of Ca(OH){sub 2} dose (10 and 20 g), Ca(OH){sub 2} source (commercial pure material or alkaline paper mill waste) and oxyanion initial concentration (from 0 to 70 mg atom/L) were investigated for this anisobaric gas-liquid-solid system. The Ca(OH){sub 2} carbonation reaction allowed successfully the removal of selenite (>90%), arsenate (>78%) and phosphate ({approx_equal}100%) from synthetic solutions. Conversely, nitrate and selenate had not any physicochemical affinity/effect during calcite formation. The rate of CO{sub 2} transfer during calcite formation in presence of oxyanions was equal or slower than for an oxyanion-free system, allowing to define a retarding kinetic factor RF that can vary between 0 (no retarding effect) to 1 (total inhibition). For selenite and phosphate RF was quite high, close to 0.3. A small retarding effect was detected for arsenate (RF {approx} 0.05) and no retarding effect was detected for selenate and nitrate (RF {approx} 0). In general, RF depends on the oxyanion initial concentration, oxyanion nature and Ca(OH){sub 2} dose. The presence of oxyanions could also influence the crystal morphology and aggregation/agglomeration process. For example, a c-axis elongation of calcite crystals was clearly observed at the equilibrium, for calcite formation in presence of selenite and phosphate. The oxyanions removal process proposed herein was inspired on the common physicochemical treatment of wastewater using calcium hydroxide (Ca(OH){sub 2}). The particularity, for this novel method is the simultaneous calcium hydroxide carbonation with compressed carbon dioxide in order to stabilise the solid matter. This economical and ecological method could allow the removal of

  1. Transportation of apical root canal after removal of calcium hydroxide when used as an intracanal medicament: An in vitro evaluation

    Directory of Open Access Journals (Sweden)

    Nurul-Ameen Inamdar

    2013-01-01

    Full Text Available Aim: To evaluate the incidence of apical root canal transportation after the removal of calcium hydroxide in straight and curved canals. Materials and Methods: Twenty maxillary central incisors (Group A and twenty mandibular molars (Group B, mesiobuccal canal were instrumented to the working length using #15 to #45 K-file and # 15 to #30 K-file, respectively. Post instrumentation digital images were taken with the corresponding final file inserted into the canal to the working length. The root canals were then filled with Calcium hydroxide paste using Lentulo spirals and the teeth incubated at 37°C for seven days. The calcium hydroxide paste was then removed up to the working length using a #45 file for group A and a pre curved #30 file for group B. Final digital images were taken with the file inserted into the canal to the working length. Post instrumentation and final digital images were superimposed to evaluate the incidence of transportation. Result: In Group A, no transportation was detected, whereas in Group B, 8 out of 20 canals showed apical transportation. Statistically significant differences were observed between Groups A and B ( P <0.05. Conclusion: Care should be taken when removing the calcium hydroxide paste from curved root canals to avoid transportation.

  2. Oily calcium hydroxide suspension (Osteoinductal) used as an adjunct to guided bone regeneration: an experimental study in rats.

    NARCIS (Netherlands)

    Stavropoulos, A.; Geenen, C.; Nyengaard, J.R.; Karring, T.; Sculean, A.

    2007-01-01

    OBJECTIVES: To evaluate whether an oily calcium hydroxide suspension (OCHS) promotes bone healing when used as an adjunct to guided bone regeneration (GBR). MATERIAL AND METHODS: Rigid, hemispherical, teflon capsules were placed with their open part facing the lateral surface of the ramus on both

  3. Comparison of modified Chicago sky blue stain and potassium hydroxide mount for the diagnosis of dermatomycoses and onychomycoses.

    Science.gov (United States)

    Liu, Zhong; Sheng, Ping; Yang, Yan-Ping; Li, Wen; Huang, Wen-Ming; Wang, Jie-Di; Fan, Yi-Ming

    2015-05-01

    The diagnostic value of modified Chicago sky blue (CSB) stain and potassium hydroxide (KOH) mount for superficial mycoses was compared using fungal culture as gold standard. The sensitivity and screening time of the CSB stain were superior to the KOH mount. The CBS stain is simple, quick and reliable for diagnosing superficial mycoses. Copyright © 2015. Published by Elsevier B.V.

  4. Efficacy of NiTi rotary instruments in removing calcium hydroxide dressing residues from root canal walls

    Directory of Open Access Journals (Sweden)

    Milton Carlos Kuga

    2012-02-01

    Full Text Available The aim of this study was to evaluate the efficacy of three rotary instrument systems (K3, ProTaper and Twisted File in removing calcium hydroxide residues from root canal walls. Thirty-four human mandibular incisors were instrumented with the ProTaper System up to the F2 instrument, irrigated with 2.5% NaOCl followed by 17% EDTA, and filled with a calcium hydroxide intracanal dressing. After 7 days, the calcium hydroxide dressing was removed using the following rotary instruments: G1 - NiTi size 25, 0.06 taper, of the K3 System; G2 - NiTi F2, of the ProTaper System; or G3 - NiTi size 25, 0.06 taper, of the Twisted File System. The teeth were longitudinally grooved on the buccal and lingual root surfaces, split along their long axis, and their apical and cervical canal thirds were evaluated by SEM (×1000. The images were scored and the data were statistically analyzed using the Kruskall Wallis test. None of the instruments removed the calcium hydroxide dressing completely, either in the apical or cervical thirds, and no significant differences were observed among the rotary instruments tested (p > 0.05.

  5. Two-dimensional metal oxide and metal hydroxide nanosheets: synthesis, controlled assembly and applications in energy conversion and storage

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Yuan, H.; Gonzalez Rodriguez, P.

    2016-01-01

    The developments and state of the art in the research on two-dimensional nanosheets derived from layered metal oxides and layered metal hydroxides are reviewed in this paper, with emphasis on their promising applications in various new energy technologies, i.e., as supercapacitor electrodes, lithium

  6. Controlling electrodeposited ultrathin amorphous Fe hydroxides film on V-doped nickel sulfide nanowires as efficient electrocatalyst for water oxidation

    Science.gov (United States)

    Shang, Xiao; Yan, Kai-Li; Lu, Shan-Shan; Dong, Bin; Gao, Wen-Kun; Chi, Jing-Qi; Liu, Zi-Zhang; Chai, Yong-Ming; Liu, Chen-Guang

    2017-09-01

    Developing cost-effective electrocatalysts with both high activity and stability remains challenging for oxygen evolution reaction (OER) in water electrolysis. Herein, based on V-doped nickel sulfide nanowire on nickel foam (NiVS/NF), we further conduct controllable electrodeposition of Fe hydroxides film on NiVS/NF (eFe/NiVS/NF) to further improve OER performance and stability. For comparison, ultrafast chemical deposition of Fe hydroxides on NiVS/NF (uFe/NiVS/NF) is also utilized. V-doping of NiVS/NF may introduce more active sites for OER, and nanowire structure can expose abundant active sites and facilitate mass transport. Both of the two depositions generate amorphous Fe hydroxides film covering on the surface of nanowires and lead to enhanced OER activities. Furthermore, electrodeposition strategy realizes uniform Fe hydroxides film on eFe/NiVS/NF confirmed by superior OER activity of eFe/NiVS/NF than uFe/NiVS/NF with relatively enhanced stability. The OER activity of eFe/NiVS/NF depends on various electrodepositon time, and the optimal time (15 s) is obtained with maximum OER activity. Therefore, the controllable electrodeposition of Fe may provide an efficient and simple strategy to enhance the OER properties of electrocatalysts.

  7. Effect of an oily calcium hydroxide suspension (Osteoinductal) on healing of intrabony periodontal defects. A pilot study in dogs.

    NARCIS (Netherlands)

    Schwarz, F.; Stratul, S.I.; Herten, M. van; Beck, B.; Becker, J.M.; Sculean, A.

    2006-01-01

    The aim of the present study was to evaluate histologically in dogs the effect of treating intrabony defects with an oily calcium hydroxide suspension (OCHS). Intrabony defects were surgically created bilaterally at the distal aspects of the maxillary first premolars and at the mesial aspects of the

  8. Room temperature synthesis of free-standing HKUST-1 membranes from copper hydroxide nanostrands for gas separation.

    Science.gov (United States)

    Mao, Yiyin; shi, Li; Huang, Hubiao; Cao, Wei; Li, Junwei; Sun, Luwei; Jin, Xianda; Peng, Xinsheng

    2013-06-25

    Large scale, robust, well intergrown free-standing HKUST-1 membranes were converted from copper hydroxide nanostrand free-standing films in 1,3,5-benzenetricarboxylic acid water-ethanol solution at room temperature, and explored for gas separation. The truncated crystals are controllable and favorable for the dense intergrowth.

  9. Treatment of a highly-concentrated sulphate-rich synthetic wastewater using calcium hydroxide in a fluidised bed crystallizer.

    Science.gov (United States)

    Maharaj, Chiara; Chivavava, Jemitias; Lewis, Alison

    2018-02-01

    This study aimed to investigate factors that affect the conversion of sulphates and magnesium, and the recovery of gypsum and magnesium hydroxide in the neutralization of a sulphate rich stream using calcium hydroxide, in a laboratory scale seeded fluidised bed crystallizer. Particular focus was on reducing the precipitated fines that escaped with the treated water, through the use of seeds, while removing as much sulphate-compounds from the waste stream as possible. The composition of the total sulphate salts was as follows: 80% magnesium sulphate, calcium sulphate remaining at its saturation concentration (1.5 g/L), with the remainder being sodium sulphate based on typical reverse osmosis retentate concentrations ranging from 1.5 - 120 g/L of total sulphate salts. The fluidised bed crystallizer, using silica seeds, was found to be effective at reducing the formation of gypsum and magnesium hydroxide fines by almost half. Feed concentrations of 35 g/L of total salts yielded better sulphate conversions (±75%), compared to a feed concentration of 8 g/L (±30%). It was possible to remove 99% of the magnesium in the saline wastewater stream using a calcium to sulphate ratio of 1:1 for feed concentrations of 15 g/L and higher. Excess calcium hydroxide suspension improved sulphate conversions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Selective Aerobic Oxidation of 5-Hydroxymethylfurfural in Water Over Solid Ruthenium Hydroxide Catalysts with Magnesium-Based Supports

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Riisager, Anders

    2011-01-01

    Solid catalyst systems comprised of ruthenium hydroxide supported on magnesium-based carrier materials (spinel, magnesium oxide and hydrotalcite) were investigated for the selective, aqueous aerobic oxidation of the biomass-derived chemical 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid...

  11. Drug intercalation in layered double hydroxide clay: Application in the development of a nanocomposite film for guided tissue regeneration

    DEFF Research Database (Denmark)

    Chakraborti, M.; Jackson, J.K.; Plackett, David

    2011-01-01

    of release by intercalation of alendronate anions in magnesium/aluminum layered double hydroxide (LDH) clay nanoparticles and dispersed in the PLGA film matrix. Tetracycline, loaded as free drug into the film together with alendronate–LDH clay complex released more rapidly than alendronate, but showed...

  12. Dehydrogenative Synthesis of Carboxylic Acids from Primary Alcohols and Hydroxide Catalyzed by a Ruthenium N-Heterocyclic Carbene Complex

    DEFF Research Database (Denmark)

    Santilli, Carola; Makarov, Ilya; Fristrup, Peter

    2016-01-01

    Primary alcohols have been reacted with hydroxide and the ruthenium complex [RuCl2(IiPr)(p-cymene)] to afford carboxylic acids and dihydrogen. The dehydrogenative reaction is performed in toluene, which allows for a simple isolation of the products by precipitation and extraction...

  13. Compressive Strength of Fly ash-based Geopolymer Concrete with a Variable of Sodium Hydroxide (NaOH Solution Molarity

    Directory of Open Access Journals (Sweden)

    Herwani

    2018-01-01

    Full Text Available Geopolymer concrete is a new material made by activating the raw materials which contain many elements of silica and alumina. Compressive strength of geopolymer concrete produced was influenced by the concentration of the activator solution. This paper presents an experimental investigation into fly ash-based geopolymer concrete. Research objective was to investigate the effects of alkaline activator solution (AAS molarity on compressive strength of geopolymer concrete. Variable of the test were a solution to sodium hydroxide was chosen as the activator solution. Concentration of sodium hydroxide solution used was 10 M, 12 M and 14 M with ambient curing. The specimen is made of concrete cylinder with diameter 10 cm and height 20 cm as many as 9 pieces each variable. Compressive strength tests is performed when the concrete is 7, 14, and 28 days old. Results of the test are indicated that the increasing of sodium hydroxide (NaOH solution concentration leads to improve the compressive strength of geopolymer concrete. The optimal compressive strength of geopolymer concrete was achieved at a concentration of sodium hydroxide solution (NaOH of 12 M. Geopolymer concretes compressive strength only achieves around 50-60% of the planned.

  14. Platinum dissolution and ethanol oxidation reaction on Pt-activated nickel foam in sodium hydroxide solution

    Directory of Open Access Journals (Sweden)

    Pierozynski Boguslaw

    2017-09-01

    Full Text Available Electrochemical oxidation of ethanol becomes an important process of modern electrochemistry, due to its potential application into direct ethanol fuel cell technology. As rates of ethanol oxidation reaction (EOR are significantly enhanced in alkaline media, employment of highly corrosion resistant under alkaline conditions, but non-noble metals becomes of superior practical importance. This communication article reports on the process of anodic dissolution of platinum, which is investigated on Pt activated, electrooxidized nickel foam electrodes, employed for ethanol oxidation reaction in 0.1 M sodium hydroxide solution. The above was revealed through the application of cyclic voltammetry and combined SEM/EDX (scanning electron microscopy and energy dispersive x-ray spectroscopy examinations.

  15. Determination of some heavy metals by flame atomic absorption spectrometry before coprecipitation with neodymium hydroxide.

    Science.gov (United States)

    Soylak, Mustafa; Kizil, Nebiye

    2011-01-01

    A procedure is described for the determination of trace amounts of Cd(II), Ni(II), Cu(II), Pb(II), Fe(III), Co(II), and Mn(II) that combines flame atomic absorption spectrometry with neodymium hydroxide coprecipitation. The influences of analytical parameters (amount of neodymium, pH of the model solutions, etc.) that affect quantitative recoveries of the analyte ions were investigated. The effects of concomitant ions were also examined. The detection limits for analytes were found in the range of 0.2-3.3 microg/L. The validation of the presented procedure was controlled by analysis of certified reference materials (National Institute of Standards and Technology 1570a spinach leaves and TMDA 54.4 fortified lake water). The applications of the procedure were performed by the analysis of water, food, and herbal plants from Turkey.

  16. Sodium Hydroxide Enhances Extractability and Analysis of Proanthocyanidins in Ensiled Sainfoin (Onobrychis viciifolia).

    Science.gov (United States)

    Ramsay, Aina; Drake, Chris; Grosse Brinkhaus, Anja; Girard, Marion; Copani, Giuseppe; Dohme-Meier, Frigga; Bee, Giuseppe; Niderkorn, Vincent; Mueller-Harvey, Irene

    2015-11-04

    Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. The acetone-butanol-HCl assay is suitable for measuring proanthocyanidin contents in a wide range of samples, silages included, but provides limited information on proanthocyanidin composition, which is of interest for deciphering the relationships between tannins and their bioactivities in terms of animal nutrition or health. Degradation with benzyl mercaptan (thiolysis) provides information on proanthocyanidin composition, but proanthocyanidins in several sainfoin silages have proved resistant to thiolysis. We now report that a pretreatment step with sodium hydroxide prior to thiolysis was needed to enable their analysis. This alkaline treatment increased their extractability from ensiled sainfoin and facilitated especially the release of larger proanthocyanidins. Ensiling reduced assayable proanthocyanidins by 29%, but the composition of the remaining proanthocyanidins in silage resembled that of the fresh plants.

  17. Fatigue Properties of Layered Double Hydroxides Modified Asphalt and Its Mixture

    Directory of Open Access Journals (Sweden)

    Xing Liu

    2014-01-01

    Full Text Available This study investigated the influence of layered double hydroxides (LDHs on the fatigue properties of asphalt mixture. In this paper, different aging levels (thin film oven test (TFOT and ultraviolet radiation aging (UV aging for short of bitumen modified with various mass ratios of the LDHs were investigated. The TFOT and UV aging process were used to simulate short-term field thermal-oxidative aging and long-term field light UV aging of bitumen, respectively. The influences of LDHs on the fatigue properties of LDHs were evaluated by dynamic shear rheometer (DSR and indirect tensile fatigue test. Results indicated that the introduction of LDHs could change the fatigue properties of bitumen under a stress control mode. The mixture with modified bitumen showed better fatigue resistance than the mixture with base bitumen. The results illustrated that the LDHs would be alternative modifiers used in the bitumen to improve the lifetime of asphalt pavements.

  18. An investigation into the chemistry of electrodeposited lanthanum hydroxide-polyethylenimine films

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Albert F.; Davies, Philip R., E-mail: daviespr@cf.ac.uk; Hurcom, Jamie; MacSorley, Jenna

    2012-01-31

    The electrodeposition of lanthanum hydroxide films onto nickel substrates in the presence of polyethylenimine (PEI) has been studied by infrared spectroscopy, x-ray photoelectron spectroscopy and atomic force microscopy with the aim of exploring the effectiveness of the technique and the chemistry of the deposited films. Maximum deposition rates were recorded for low concentrations of PEI with rates decreasing at higher PEI concentrations largely because of the poor structural integrity of the deposited films. Similarly, extending the deposition times did not improve film coverage as thicker films adhered less well to the nickel substrate. The deposited films were shown to contain co-deposited PEI with the concentration remaining constant within the films during deposition but changing linearly with PEI concentration in the depositing solution.

  19. Synthesis of nanocomposite coating based on TiO2/ZnAl layer double hydroxides

    Directory of Open Access Journals (Sweden)

    V. Jovanov

    2017-02-01

    Full Text Available The aim of this investigation was the synthesis of nanocomposite coatings based on Zn-Al layered double hydroxides (Zn-Al LDH and TiO2. The Zn-Al LDH material, which acted as the catalyst support of the active TiO2 component (in the content of 3 and 10 wt. %, was synthesized by a low super saturation co-precipitation method. The interaction between the Zn-Al LDH and the active TiO2 component was accomplished by using vacuum evaporation prior to the mechanical activation and only by mechanical activation. The final suspension based on Zn-Al LDH and 10wt. % TiO2, impregnated only by mechanical activation, showed the optimal characteristics from the aspect of particle size distribution and XRD analysis. These properties had a positive effect on the functional properties of the coatings (photocatalytic activity and self-cleaning efficiency after the water rinsing procedure.

  20. Recent advances in polymer supporting layered double hydroxides nanocomposite for electrochemical biosensors

    Science.gov (United States)

    Dhanasekaran, T.; Padmanaban, A.; Gnanamoorthy, G.; Manigandan, R.; Praveen Kumar, S.; Stephen, A.; Narayanan, V.

    2018-01-01

    In recent years, layered double hydroxides (LDHs) materials having emerging due to their ability of intercalate a variety of anions, either organic or inorganic molecules. The most significance of the LDHs has been found potential applications in catalysis, wastewater treatment, and electrochemical sensors. The Mg–Al LDHs (MAL) and Poly-o-phenylenediamine @ Mg–Al LDHs (P-MAL) was prepared via simple one step hydrothermal method. As prepared material was characterized using many techniques such as, the structural and crystal phase was determined from XRD and Raman analyses. The functional groups were depicted using FT-IR spectroscopy. The optical propertied studied using diffuse reflectance spectroscopy UV–vis spectroscopy and the emission property were analyzed from Photoluminescence spectroscopy. The surface morphology and average particle size was analyzed using FESEM microscopy. The prepared polymer composite material P-MAL was further used for highly sensitive electrochemical detection towards dopamine (DA).

  1. Glycine buffered synthesis of layered iron(II)-iron(III) hydroxides (green rusts)

    DEFF Research Database (Denmark)

    Yin, Weizhao; Huang, Lizhi; Pedersen, Emil Bjerglund

    2017-01-01

    H fluctuations during base addition and hence allows for fast GRSO4 precipitation, minimizing byproduct formation. The use of other pH buffers [4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid and 2-amino-2-(hydroxymethyl)-1,3-propanediol] was also tested but failed. Mössbauer spectroscopy, X-ray diffraction......Layered Fe(II)-Fe(III) hydroxides (green rusts, GRs) are efficient reducing agents against oxidizing contaminants such as chromate, nitrate, selenite, and nitroaromatic compounds and chlorinated solvents. In this study, we adopted a buffered precipitation approach where glycine (GLY) was used...... in the absence of GLY, synthesis failed under similar conditions. Gycine functions as both a pH buffer and a ligand; Fe(II)-GLY complexes serve as a source of base (Fe(II)-GLY+H2O→Fe(II)+H-GLY+OH(-)) during GR formation, supplying about 45% of the total base required for the synthesis. The GLY buffer decreases p...

  2. Electrochemical Performance of Zn-Al Double Layered Hydroxide for Supercapacitor Application

    Science.gov (United States)

    Wen, Yang; Zhao, Yu; Lu, Lu; Zhang, Shuo Jia; Xu, Bing

    2017-10-01

    Zn-Al double layered hydroxide (Zn-Al-LDH) was synthesized by a facile coprecipitation method. The morphology and microstructure of samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM), respectively. The results show that the sample is uniform nanosheet with the diameter of ∼400 nm and the thickness of ∼80 nm. XRD characterization confirms that it is Zn6A12(OH)16CO3.4H2O and belongs to Rhombohedral crystallographic system. Electrochemical performances of the sample were investigated by cyclic voltammery (CV) and charge/discharge. The Pure Zn-Al-LDH nanocomposites achieves a specific capacitance of 37.0 F g-1 at the current density of 1.0 A/g.

  3. A solution blending route to ethylene propylene diene terpolymer/layered double hydroxide nanocomposites

    Directory of Open Access Journals (Sweden)

    Bhowmick Anil

    2006-01-01

    Full Text Available AbstractEthylene propylene diene terpolymer (EPDM/MgAl layered double hydroxide (LDH nanocomposites have been synthesized by solution intercalation using organically modified LDH (DS-LDH. The molecular level dispersion of LDH nanolayers has been verified by the disappearance of basal XRD peak of DS-LDH in the composites. The internal structures, of the nanocomposite with the dispersion nature of LDH particles in EPDM matrix have been studied by TEM and AFM. Thermogravimetric analysis (TGA shows thermal stability of nanocomposites improved by ≈40 °C when 10% weight loss was selected as point of comparison. The degradation for pure EPDM is faster above 380 °C while in case of its nanocomposites, it is much slower.

  4. Tunable Properties of Exfoliated Polyvinylalcohol Nanocomposites by In Situ Coprecipitation of Layered Double Hydroxides

    Science.gov (United States)

    Liu, Jiajia; Yuen, Richard K. K.; Hu, Yuan

    2017-10-01

    Poly(vinyl alcohol) (PVA) nanocomposites were prepared by a “one step” method based on the coprecipitation of layered double hydroxide (LDH) nanosheets in the polymer aqueous solution. The morphology, fire resistance properties, mechanical and optical properties of the PVA/LDH nanocomposites were studied. The LDH nanosheets were homogeneously dispersed in the PVA matrix as indicated by X-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) characterization. Meanwhile, the peak of heat release rate (pHRR) and total heat release (THR) were decreased by 58% and 28%, respectively. Storage modulus at 30 °C was increased, and the transmittance of more than 90% at the visible region was obtained upon addition of 5 wt% LDH.

  5. APPLICATIONS OF LAYERED DOUBLE HYDROXIDES IN REMOVING OXYANIONS FROM OIL REFINING AND COAL MINING WASTEWATER

    Energy Technology Data Exchange (ETDEWEB)

    Song Jin; Paul Fallgren

    2006-03-01

    Western Research Institute (WRI), in conjunction with the U.S. Department of Energy (DOE), conducted a study of using the layered double hydroxides (LDH) as filter material to remove microorganisms, large biological molecules, certain anions and toxic oxyanions from various waste streams, including wastewater from refineries. Results demonstrate that LDH has a high adsorbing capability to those compounds with negative surface charge. Constituents studied include model bacteria, viruses, arsenic, selenium, vanadium, diesel range hydrocarbons, methyl tert-butyl ether (MTBE), mixed petroleum constituents, humic materials and anions. This project also attempted to modify the physical structure of LDH for the application as a filtration material. Flow characterizations of the modified LDH materials were also investigated. Results to date indicate that LDH is a cost-effective new material to be used for wastewater treatment, especially for the treatment of anions and oxyanions.

  6. Improved extraction procedures for polychlorinated biphenyls in solid samples with aqueous sodium hydroxide under autoclave conditions.

    Science.gov (United States)

    Akimoto, Y; Inouye, Y

    2000-03-01

    The efficacy of the extraction of polychlorinated biphenyls (PCBs) from varnish-infiltrated insulating papers as a model of solid materials with an aqueous sodium hydroxide (NaOH) by autoclaving at 121 degrees C for 30 min was compared with those for the conventional procedures, i.e., saponification with 1 N ethanolic NaOH in a boiling water bath for 60 min and extraction with benzene in a Soxhlet apparatus. The newly invented autoclaving method was found to be superior to the conventional ones, yielding approximately 5- to 6-fold cumulative PCB congeners without being accompanied by extended decomposition. Therefore, the autoclave-based sample treatment is recommended for more accurate determination of PCBs in the case of PCB-impregnated solid materials such as hardened oils and resin-coated or -infiltrated papers instead of being treated conventionally.

  7. Cellular Fe-hydroxides and heavy metal sorption in Euglena sp. (algae): implications for biomineralization

    Energy Technology Data Exchange (ETDEWEB)

    Mann, H.; Beveridge, T.O. Fyfe, W.S.; Tazaki, K.

    1985-01-01

    STEM imagery and electron diffraction patterns of Euglena sp. reveal pronounced intra and cellular-membrane aggregates of Fe-hydroxides (some lepidocrocite), in natural communities from tailings waters, Elliott Lake, Ontario. Pure isolates of Euglena sp. contain 40-70% Fe by dry weight and in addition average Al 28,000 ppm, Sr 150, Ba 40, Zn 150, Mn 250, Ni 120, Pb 1600, Th 70, Cu 200 and U 180. In tailings waters, Fe solute concentrations average 560 ppm and U 50 ppb. Concentration factors for Fe, Ba, Zn, Mn, Ti, V, Ni, Pb, Cr, Ag, Co and Cu in algae referenced to average world river waters are greater than or equal to 10/sup 6/. These results endorse the premise that microorganisms mediate transfer of many solutes between the hydrosphere and sedimentary regime.

  8. Success rate of calcium hydroxide pulpotomy in primary molars restored with amalgam and stainless steel crowns.

    Science.gov (United States)

    Sonmez, D; Duruturk, L

    2010-05-08

    To compare the success rate of calcium hydroxide (Ca(OH)(2)) pulpotomies in primary molars restored with a stainless steel crown (SSC) to that of teeth restored with amalgam and to evaluate the role of restoration failure in treatment outcome. Pulpotomies were performed in 154 primary molars. Teeth were grouped according to pulpal exposure type as either mechanically or cariously exposed, with cariously exposed teeth further divided according to size of exposure site (pinpoint or larger than pinpoint). Seventy teeth were restored with amalgam and 84 with a SSC. Teeth were followed up for 12 months. Pulpotomy success rates were 79.9% for teeth restored with a SSC and 60% for those restored with amalgam. The difference between these rates was statistically significant (p 0.05). The pulpotomy success rate for teeth restored with a SSC was higher than for those restored with amalgam. Restoration failure did not appear to have an effect on treatment prognosis.

  9. Interlayer Structure of Bioactive Molecule, 2-Aminoethanesulfonate, Intercalated into Calcium-Containing Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Tae-Hyun Kim

    2012-01-01

    Full Text Available We have successfully intercalated 2-aminoethanesulfonate, a well-known biomolecule taurine, into calcium-containing layered double hydroxides via optimized solid phase intercalation. According to X-ray diffraction patterns and infrared spectroscopy, it was revealed that the intercalated taurine molecules were each directly coordinated to other calcium cation and arranged in a zig-zag pattern. Scanning electron microscopy showed that the particle size and morphology of the LDHs were not affected by the solid phase intercalation, and the surface of intercalates was covered by organic moieties. From ninhydrin amine detection tests, we confirmed that most of the taurine molecules were well stabilized between the calcium-containing LDH layers.

  10. Metallic Nickel Hydroxide Nanosheets Give Superior Electrocatalytic Oxidation of Urea for Fuel Cells.

    Science.gov (United States)

    Zhu, Xiaojiao; Dou, Xinyu; Dai, Jun; An, Xingda; Guo, Yuqiao; Zhang, Lidong; Tao, Shi; Zhao, Jiyin; Chu, Wangsheng; Zeng, Xiao Cheng; Wu, Changzheng; Xie, Yi

    2016-09-26

    The direct urea fuel cell (DUFC) is an important but challenging renewable energy production technology, it offers great promise for energy-sustainable developments and mitigating water contamination. However, DUFCs still suffer from the sluggish kinetics of the urea oxidation reaction (UOR) owing to a 6 e(-) transfer process, which poses a severe hindrance to their practical use. Herein, taking β-Ni(OH)2 nanosheets as the proof-of-concept study, we demonstrated a surface-chemistry strategy to achieve metallic Ni(OH)2 nanosheets by engineering their electronic structure, representing a first metallic configuration of transition-metal hydroxides. Surface sulfur incorporation successfully brings synergetic effects of more exposed active sites, good wetting behavior, and effective electron transport, giving rise to greatly enhanced performance for UOR. Metallic nanosheets exhibited a much higher current density, smaller onset potential and stronger durability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Production of activated carbons from pyrolysis of waste tires impregnated with potassium hydroxide.

    Science.gov (United States)

    Teng, H; Lin, Y C; Hsu, L Y

    2000-11-01

    Activated carbons were produced from waste tires using a chemical activation method. The carbon production process consisted of potassium hydroxide (KOH) impregnation followed by pyrolysis in N2 at 600-900 degrees C for 0-2 hr. The activation method can produce carbons with a surface area (SA) and total pore volume as high as 470 m2/g and 0.57 cm3/g, respectively. The influence of different parameters during chemical activation, such as pyrolysis temperature, holding time, and KOH/tire ratio, on the carbon yield and the surface characteristics was explored, and the optimum preparation conditions were recommended. The pore volume of the resulting carbons generally increases with the extent of carbon gasified by KOH and its derivatives, whereas the SA increases with degree of gasification to reach a maximum value, and then decreases upon further gasification.

  12. Layered double hydroxide nanoparticles as target-specific delivery carriers: uptake mechanism and toxicity.

    Science.gov (United States)

    Choi, Soo-Jin; Choy, Jin-Ho

    2011-07-01

    Layered double hydroxides (LDHs), also known as anionic nanoclays or hydrotalcite-like compounds, have attracted a great deal of interest for their potential as delivery carriers. In this article, we describe the cellular uptake behaviors and uptake pathway of LDHs in vitro and in vivo, which can not only explain the mechanism by which high efficacy of biomolecules delivered through LDH nanocarriers could be obtained, but also provide novel strategies to enhance their delivery efficiency. Toxicological effects of LDHs in cell lines and in animal models are also present, aiming at providing critical information about their toxicity potential, which should be carefully considered for their biomedical application. Understanding the uptake behaviors, uptake mechanism and toxicity of LDHs in terms of dose-response relationship, diverse physicochemical properties and interaction with different biological systems is important to optimize delivery efficiency as well as biocompatibility.

  13. Fabrication of nanosized cobalt powder from Cobalt(II) hydroxide of spent lithium ion battery

    Science.gov (United States)

    Yun, Jung-Yeul; Park, Dahee; Jung, Sung-Sik; Wang, Jei-Pil

    2017-09-01

    This study was investigated to fabricate nanosized cobalt (Co) powder from cobalt hydroxide Co(OH)2 recovered from spent lithium ion battery. Direct process newly proposed was attempted to transform phases as follow: Co(OH)2 → Co3O4 → Co. The variation of weight with time of the sample was measured using thermogravimetric analysis (TGA) and it was found that weight loss was observed over 500 °C. Thermal treatment was conducted to determine proper operating time for phase transformation of Co3O4 at 500 °C. Subsequently, hydrogen reduction was carried out on the effect of temperature, reaction time and flowrate. In the long run, nanosized cobalt powder was successfully fabricated with a mean particle size of 100-500 nm as well as purity of 99.21 wt.%.

  14. Removal of Pb{sup 2+} from the aqueous solution by tartrate intercalated layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yanming; Zhao, Xiaolei; Zhang, Xi; Li, Shifeng; Liu, Dongbin; Fan, Lihui [Shenyang University of Chemical Technology, Shenyang (China)

    2016-01-15

    Adsorption of Pb{sup 2+} ion by a tartrate intercalated MgAl layered double hydroxides (MgAl-TA LDHs) was studied. The adsorption isotherms and kinetics were investigated as a function of various experimental parameters using batch adsorption experiments. The results indicated that the adsorption isotherm was well described by Sips model. The kinetic adsorption data were fitted well to the pseudo-second-order kinetic equation. The adsorption of Pb{sup 2+} was controlled mainly by the chemical process combined with intraparticle diffusion. Parameters of adsorption thermodynamic suggested that the interaction of Pb{sup 2+} adsorbed by MgAl-TA LDHs adsorbents was thermodynamically spontaneous and endothermic.

  15. Silver Orthophosphate Immobilized on Flaky Layered Double Hydroxides as the Visible-Light-Driven Photocatalysts

    Directory of Open Access Journals (Sweden)

    Xianlu Cui

    2012-01-01

    Full Text Available Flaky layered double hydroxide (FLDH was prepared by the reconstruction of its oxide in alkali solution. The composites with FLDH/Ag3PO4 mass ratios at 1.6 : 1 and 3 : 1 were fabricated by the coprecipitation method. The powders were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscope, and UV-vis diffuse reflectance spectroscopy. The results indicated that the well-distributed Ag3PO4 in a fine crystallite size was formed on the surface of FLDH. The photocatalytic activities of the Ag3PO4 immobilized on FLDH were significantly enhanced for the degradation of acid red G under visible light irradiation compared to bare Ag3PO4. The composite with the FLDH/Ag3PO4 mass ratio of 3 : 1 showed a higher photocatalytic efficiency.

  16. Study on synthesizing Mg/Al layered double hydroxides at different pHs

    Directory of Open Access Journals (Sweden)

    E Otgonjargal

    2014-12-01

    Full Text Available Mg/Al layered double hydroxide (LDH was successfully synthesized at different pHs values. The Mg/AL LDH was well characterized by X-Ray diffraction and Fourier transform infrared analysis. The morphology of the LDH was observed using Scanning electron microscopy with energy dispersive X-ray spectroscopy. The influence of pH values on the morphology of the Mg/Al LDHs were studied. The result showed that the well-synthesized Mg/Al LDHs could be obtained when the pH value was about 10.0 at room temperature.DOI: http://doi.dx.org/10.5564/mjc.v15i0.319 Mongolian Journal of Chemistry 15 (41, 2014, p36-39

  17. Zn-Al LAYERED DOUBLE HYDROXIDE PILLARED BY DIFFERENT DICARBOXYLATE ANIONS

    Directory of Open Access Journals (Sweden)

    S. Gago

    2004-12-01

    Full Text Available Zn-Al layered double hydroxides (LDHs intercalated by terephthalate (TPH and biphenyl-4,4'-dicarboxylate (BPH anions have been synthesized by direct co-precipitation from aqueous solution. The Zn/Al ratio in the final materials was 1.8. The products were characterized by powder X-ray diffraction, thermogravimetric analysis, FTIR and FT Raman spectroscopy, and MAS NMR spectroscopy. The basal spacing for the TPH-LDH intercalate was 14.62 Å, indicating that the guest anions stack to form a monolayer with the aromatic rings perpendicular to the host layers. For the LDH intercalate containing BPH anions, a basal spacing of at least 19.2 Å would be expected if the anions adopted an arrangement similar to that for the TPH anions. The observed spacing was 18.24 Å, suggesting that the anions are tilted slightly with respect to the host layers.

  18. Immobilization of HRP Enzyme on Layered Double Hydroxides for Biosensor Application

    Directory of Open Access Journals (Sweden)

    Zouhair M. Baccar

    2011-01-01

    Full Text Available We present a new biosensor for hydrogen peroxide (H2O2 detection. The biosensor was based on the immobilization of horseradish peroxidase (HRP enzyme on layered double hydroxides- (LDH- modified gold surface. The hydrotalcite LDH (Mg2Al was prepared by coprecipitation in constant pH and in ambient temperature. The immobilization of the peroxidase on layered hybrid materials was realized via electrostatic adsorption autoassembly process. The detection of hydrogen peroxide was successfully observed in PBS buffer with cyclic voltammetry and the chronoamperometry techniques. A limit detection of 9 μM of H2O2 was obtained with a good reproducibility. We investigate the sensitivity of our developed biosensor for H2O2 detection in raw milk.

  19. Removal of lead from aqueous solution on glutamate intercalated layered double hydroxide

    Directory of Open Access Journals (Sweden)

    Shen Yanming

    2017-05-01

    Full Text Available Glutamate intercalated Mg–Al layered double hydroxide (LDH was prepared by co-precipitation and the removal of Pb2+ in the aqueous solution was investigated. The prepared samples were characterized by XRD, FT-IR and SEM. It was shown that glutamate can intercalate into the interlayer space of Mg–Al LDH. The glutamate intercalated Mg–Al LDH can effectively adsorb Pb2+ in the aqueous solution with an adsorption capacity of 68.49 mg g−1. The adsorption of Pb2+ on glutamate intercalated Mg–Al LDH fitted the pseudo-second-order kinetics model and the isotherm can be well defined by Langmuir model.

  20. Layered double hydroxide nanosheet as a two-dimensional support of dense platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hyo Gyoung; Cho, Se Hee; Ji, Hong Geun [H and A PharmaChem, R and D center, Bucheon (Korea, Republic of); Lee, Jong Hyeon [Dept. of Chemistry, The Catholic University of Korea, Bucheon (Korea, Republic of)

    2017-02-15

    Transition metal nanoparticles (NPs) with a narrow size distribution have been intensively synthesized on various solid supports for anti-agglomeration, and high catalytic activity and selectivity. Layered double hydroxides (LDH) are currently attracting intense interest in the field of heterogeneous catalysis as catalyst supports. In order to obtain a well-crystallized LDH nanosheet, the as-synthesize d carbonate form of LDH was hydrothermally treated according to a reported procedure, and further reacted by anion-exchange with an aqueous solution of NaNO{sub 3} and acetate buffer to give the nitrate form of LDH. Dense and uniform Pt NPs were synthesized on the exfoliated LDH nanosheets through precursor exchange and thermal reduction of the precursor ions. In this nanocomposite, the Pt Nps were uniformly grown on the surface of the LDH nano sheet and the average size of Pt Nps was 2nm.