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Sample records for cesium immobilization synthese

  1. Immobilization of cesium in alkaline activated fly ash matrix

    Science.gov (United States)

    Fernandez-Jimenez, A.; Macphee, D. E.; Lachowski, E. E.; Palomo, A.

    2005-11-01

    The immobilization potential of alkaline activated fly ash (AAFA) matrices for cesium has been investigated. The presence of Cs in the AAFA pastes, prepared using 8M NaOH solution as activator, showed no significant adverse effects on mechanical strength or microstructure, nor were significant quantities of Cs leached following application of the Toxic Characteristic Leaching Procedure (TCLP) and American Nuclear Society (ANS) 16.1 leaching protocols. Microstructural analysis shows Cs associated with the main reaction product in the AAFA suggesting that cesium is chemically bound rather than physically encapsulated. It is proposed that cesium is incorporated into the alkaline aluminosilicate gel, a precursor for zeolite formation.

  2. Removal of cesium from nuclear liquid waste using hybrid organic-inorganic membranes grafted by immobilized calixarenes; Synthese et caracterisation de membranes hybrides organo-minerales contenant des calixarenes. Application au traitement des effluents radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Duhart, A

    1998-07-01

    The aim of the Actinex program is to reduce massively the noxiousness of the vitrified wastes mainly due to actinides and other long-lived fission products such as {sup 129}I, {sup 99}Tc or {sup 135}Cs. Specific treatment means applicable to the industrial processes of spent fuel reprocessing have to be defined. The selective extraction of these radioelements for their transmutation or packaging in specific matrices is one of the research theme of this program. Different studies allowing the extraction of radioelements such as cesium, americium and plutonium by preferential diffusional transport through a supported liquid membrane of complexes (formed between a selective transport compound and the radioelements) are at the present time carried out in the ETPL (Effluents Treatment Processes Laboratory). Calix-4-arenes mono/bis-crown-6 are used as selective transport compounds. Meanwhile the possible losses of the selective transport compound by dissolution in the aqueous phases have oriented our researches towards a solid material in which the selective transport compound is chemically bound or trapped in the matrix. The transport compound is a calixarene, dissymmetrical and double grafted. It has been specifically synthesized for this study. It allows both to complex the cesium and to chemically bind a hetero-poly-siloxane. These monomers have poly-condensable groups which lead by sol-gel process to the formation of a three-dimensional bonds lattice. The matrix, thus obtained, can be supported either on a mineral material or on a porous organic material. Pre-polymers and the deposited layers have been characterized and correlations between the materials preparation and their properties, applied to cesium extraction, have been established. Experiments of cesium transfer through the solid membrane containing between 2 to 40% of selective transport compound, located between 2 compartments containing upstream, an acidic solution with strong salinity doped with Cs 137

  3. Removal of cesium ion in aqueous solution using immobilized sericite beads

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Choong [Kwandong University, Gangneung (Korea, Republic of); Kim, Jong-Oh [Hanyang University, Seoul (Korea, Republic of); Lee, Seung-Mok [Gangneung-Wonju National University, Gangneung (Korea, Republic of)

    2014-07-15

    To apply sericite effectively in the adsorption process, it was immobilized by entrapment method using sodium alginate. Since the immobilized sericite beads have excellent mechanical strength and swelling characteristics, channeling of flow and the increase of pressure drop were not observed through column operations. In addition, it was also stable under pH 10 and 45 .deg. C of cesium solution. The maximum adsorption capacity and Langmuir adsorption constant was 1.430mg/g and 2.329 L/mg, respectively, at initial pH 5 of cesium solution in batch type and the Langmuir model with higher correlation coefficient of 0.997 fits experimental data better than Freundlich model. The breakthrough point emerged around 15 (1.0 mL/min) and 20 bed volumes (0.5 mL/min), and the cesium ions bound to the immobilized sericite beads were readily released and quantitatively recovered by a few bed volumes of 1.0M of HNO{sub 3} solution. Furthermore, bed volumes of cesium ions for firstly reused sericite beads can be still maintained as 18, which shows good regeneration ability.

  4. Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Awual, Md. Rabiul, E-mail: awual.rabiul@jaea.go.jp [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Yaita, Tsuyoshi [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan); Taguchi, Tomitsugu [Nano-Structure Synthesis Research Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro [Actinide Coordination Chemistry Group, Quantum Beam Science Centre (QuBS), Japan Atomic Energy Agency (SPring-8), Hyogo 679-5148 (Japan)

    2014-08-15

    Graphical abstract: - Highlights: • DB24C8 crown ether was functionalized for preparation of conjugate adsorbent. • Radioactive {sup 137}Cs can be selectively removed by the conjugate adsorbent. • Adsorbent can effectively capture Cs even in the presence of a high amount Na and K. • Adsorbent is reversible and able to be reused without significant deterioration. - Abstract: Conjugate materials can provide chemical functionality, enabling an assembly of the ligand complexation ability to metal ions that are important for applications, such as separation and removal devices. In this study, we developed ligand immobilized conjugate adsorbent for selective cesium (Cs) removal from wastewater. The adsorbent was synthesized by direct immobilization of dibenzo-24-crown-8 ether onto inorganic mesoporous silica. The effective parameters such as solution pH, contact time, initial Cs concentration and ionic strength of Na and K ion concentrations were evaluated and optimized systematically. This adsorbent was exhibited the high surface area-to-volume ratios and uniformly shaped pores in case cavities, and its active sites kept open functionality to taking up Cs. The obtained results revealed that adsorbent had higher selectivity toward Cs even in the presence of a high concentration of Na and K and this is probably due to the Cs–π interaction of the benzene ring. The proposed adsorbent was successfully applied for radioactive Cs removal to be used as the potential candidate in Fukushima nuclear wastewater treatment. The adsorbed Cs was eluted with suitable eluent and simultaneously regenerated into the initial form for the next removal operation after rinsing with water. The adsorbent retained functionality despite several cycles during sorption-elution-regeneration operations.

  5. Experimental study on cesium immobilization in struvite structures.

    Science.gov (United States)

    Wagh, Arun S; Sayenko, S Y; Shkuropatenko, V A; Tarasov, R V; Dykiy, M P; Svitlychniy, Y O; Virych, V D; Ulybkina, Е А

    2016-01-25

    Ceramicrete, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate that has a struvite-K mineral structure. In this study, we demonstrate that this crystalline structure is ideal for incorporating radioactive Cs into a Ceramicrete matrix. This is accomplished by partially replacing K by Cs in the struvite-K structure, thus forming struvite-(K, Cs) mineral. X-ray diffraction and thermo-gravimetric analyses are used to confirm such a replacement. The resulting product is non-leachable and stable at high temperatures, and hence it is an ideal matrix for immobilizing Cs found in high-activity nuclear waste streams. The product can also be used for immobilizing secondary waste streams generated during glass vitrification of spent fuel, or the method described in this article can be used as a pretreatment method during glass vitrification of high level radioactive waste streams. Furthermore, it suggests a method of producing safe commercial radioactive Cs sources.

  6. Immobilization of Cesium Traps from the BN-350 Fast Reactor (Aktau, Kazakhstan)

    Energy Technology Data Exchange (ETDEWEB)

    J. A. Michelbacher; C. Knight; O. G. Romanenko; I. L. Tazhibaeva; I. L. Yakovlev; A. V. Rovneyko; V. I. Maev; D. Wells; A. Herrick

    2011-03-01

    During BN-350 reactor operations and also during the initial stages of decommissioning, cesium traps were used to decontaminate the reactor’s primary sodium coolant. Two different types of carbon-based trap were used – the MAVR series, low ash granulated graphite adsorber (LAG) contained in a carrier designed to be inserted into the reactor core during shutdown; and a series of ex-reactor trap accumulators(TAs) which used reticulated vitreous carbon (RVC) to reduce Cs-137 levels in the sodium after final reactor shutdown. In total four MAVRs and seven TAs were used at BN-350 to remove an estimated cumulative 755 TBq of cesium. The traps, which also contain residual sodium, need to be immobilized in an appropriate way to allow them to be consigned as waste packages for long term storage and, ultimately, disposal. The present paper reports on the current status of the implementation phase, with particular reference to the work done to date on the trap accumulators, which have the most similarity with the cesium traps used at other reactors.

  7. Sintered bentonite ceramics for the immobilization of cesium- and strontium-bearing radioactive waste

    Science.gov (United States)

    Ortega, Luis Humberto

    The Advanced Fuel Cycle Initiative (AFCI) is a Department of Energy (DOE) program, that has been investigating technologies to improve fuel cycle sustainability and proliferation resistance. One of the program's goals is to reduce the amount of radioactive waste requiring repository disposal. Cesium and strontium are two primary heat sources during the first 300 years of spent nuclear fuel's decay, specifically isotopes Cs-137 and Sr-90. Removal of these isotopes from spent nuclear fuel will reduce the activity of the bulk spent fuel, reducing the heat given off by the waste. Once the cesium and strontium are separated from the bulk of the spent nuclear fuel, the isotopes must be immobilized. This study is focused on a method to immobilize a cesium- and strontium-bearing radioactive liquid waste stream. While there are various schemes to remove these isotopes from spent fuel, this study has focused on a nitric acid based liquid waste. The waste liquid was mixed with the bentonite, dried then sintered. To be effective sintering temperatures from 1100 to 1200°C were required, and waste concentrations must be at least 25 wt%. The product is a leach resistant ceramic solid with the waste elements embedded within alumino-silicates and a silicon rich phase. The cesium is primarily incorporated into pollucite and the strontium into a monoclinic feldspar. The simulated waste was prepared from nitrate salts of stable ions. These ions were limited to cesium, strontium, barium and rubidium. Barium and rubidium will be co-extracted during separation due to similar chemical properties to cesium and strontium. The waste liquid was added to the bentonite clay incrementally with drying steps between each addition. The dry powder was pressed and then sintered at various temperatures. The maximum loading tested is 32 wt. percent waste, which refers to 13.9 wt. percent cesium, 12.2 wt. percent barium, 4.1 wt. percent strontium, and 2.0 wt. percent rubidium. Lower loadings of waste

  8. Fabrication, characterization and radiation damage stability of hollandite based ceramics devoted to radioactive immobilisation; Synthese, caracterisation et etude du comportement sous irradiation electronique de matrices de type hollandite destinees au confinement du cesium radioactif

    Energy Technology Data Exchange (ETDEWEB)

    Aubin-Chevaldonnet, V. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DETCD/SCDV), Dept. d' Etudes du Traitement et du Conditionnement des Dechets, Service de Conditionnement des Dechets et Vitrification, 30 - Marcoule (France)

    2004-11-01

    Research on treating specifically the long-lived and high level nuclear wastes, notably cesium, is currently carried out in France. Cesium immobilization in host matrices of high chemical durability constitutes the favoured option. Hollandite matrix is a good candidate because of its high cesium incorporation ability and its excellent chemical stability. During this study, different compositions of hollandite ceramics Ba{sub x}Cs{sub y}C{sub z}Ti{sub 8-z}O{sub 16} (C = Al{sup 3+}, Cr{sup 3+}, Ga{sup 3+}, Fe{sup 3+}, Mg{sup 2+}, Sc{sup 3+}), synthesized by oxide route, were characterized in terms of structure, microstructure and physical and chemical properties. Iron ions seems to be the most suitable of the studied C cations to get high-performance hollandites. The stability of these ceramics under external electron irradiation, simulating the {beta} particles emitted by radioactive cesium, were also estimated, at the macroscopic and atomic scale. The point defects creation and their thermal stability were followed by electron paramagnetic resonance. (author)

  9. Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension

    Energy Technology Data Exchange (ETDEWEB)

    Mallampati, Srinivasa Reddy, E-mail: srireddys@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Mitoma, Yoshiharu, E-mail: mitomay@pu-hiroshima.ac.jp [Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara City, Hiroshima 727-0023 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Sakita, Shogo [Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho, Shobara City, Hiroshima 727-0023 (Japan); Simion, Cristian [Politehnica University of Bucharest, Department of Organic Chemistry, Bucharest 060042 (Romania)

    2014-08-30

    Graphical abstract: Schematic representation of possible mechanisms determining the Cs extraction and immobilization in fly ash during water, methanol or n-MCaS extraction. - Highlights: • nMCaS suspension for cesium extraction and immobilization in fly ash was developed. • Enhanced cesium immobilization was done by nanometallic Ca/CaO methanol suspension. • By SEM analysis the amount of cesium detectable on soil particle surface decreases. • Leachable cesium concentrations reduced, lower than the standard regulatory limit. • nMCaS unique and a highly potential amendment for the remediation of Cs. - Abstract: In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ({sup 133}Cs) and radioactive cesium species ({sup 134}Cs and {sup 137}Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of {sup 133}Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of {sup 133}Cs. SEM-EDS analysis revealed that the mass percent of detectable {sup 133}Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040 Bq kg{sup −1134}Cs and {sup 137}Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583 Bq kg{sup −1} after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100 Bq L{sup −1} total {sup 134}Cs and {sup 137}Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of {sup 134}Cs and {sup 137}Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000 Bq kg{sup −1} and 150 Bq L{sup −1} respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is

  10. Cation exchange applications of synthetic tobermorite for the immobilization and solidification of cesium and strontium in cement matrix

    Indian Academy of Sciences (India)

    O P Shrivastava; Rashmi Shrivastava

    2000-12-01

    Immobilization and solidification of hazardous cations like Cs137 and Sr90 are required while handling the radioactive waste of nuclear power plants. Efforts are on to find a fail proof method of safe disposal of nuclear wastes. In this context, various materials like borosilicate glass, zeolites, cements and synthetic rocks have been tried by several workers. This communication deals with the synthesis, characterization, cesium uptake capacity and leaching behaviour of synthetic alumina-substituted calcium silicate hydroxy hydrate, which are close to that obtained for the natural mineral, 11 Å tobermorite. The synthetic mineral show cation selectivity for Cs+ in presence of 500–1000 times concentrated solutions of Na+ , K+ , Mg2+, Ca2+ , Ba2+ and Sr2+. Although the ordinary portland cement (OPC) which is often used in waste management operations alone holds negligible amounts of Cs+ and Sr2+, the addition of alumina-substituted tobermorite to OPC enhances the retention power of cement matrix by drastically lowering the leach rate of cations.

  11. Preferential removal and immobilization of stable and radioactive cesium in contaminated fly ash with nanometallic Ca/CaO methanol suspension.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Sakita, Shogo; Simion, Cristian

    2014-08-30

    In this work, the capability of nanometallic Ca/CaO methanol suspension in removing and/or immobilizing stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs) in contaminated fly ash was investigated. After a first methanol and second water washing yielded only 45% of (133)Cs removal. While, after a first methanol washing, the second solvent with nanometallic Ca/CaO methanol suspension yielded simultaneous enhanced removal and immobilization about 99% of (133)Cs. SEM-EDS analysis revealed that the mass percent of detectable (133)Cs on the fly ash surface recorded a 100% decrease. When real radioactive cesium contaminated fly ash (containing an initial 14,040Bqkg(-1)(134)Cs and (137)Cs cumulated concentration) obtained from burning wastes from Fukushima were reduced to 3583Bqkg(-1) after treatment with nanometallic Ca/CaO methanol suspension. Elution test conducted on the treated fly ash gave 100BqL(-1) total (134)Cs and (137)Cs concentrations in eluted solution. Furthermore, both ash content and eluted solution concentrations of (134)Cs and (137)Cs were much lower than the Japanese Ministry of the Environment regulatory limit of 8000Bqkg(-1) and 150BqL(-1) respectively. The results of this study suggest that the nanometallic Ca/CaO methanol suspension is a highly potential amendment for the remediation of radioactive cesium-contaminated fly ash.

  12. Immobilization of Biocatalysts and Cells on Hybrid Membranes Syntheses on Sol-gel Method

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    Yotova L.

    2007-12-01

    Full Text Available The investigations in the area of enzyme action in the living organisms give us the opportunity for applications of these biochemical catalysts in the different purposes of medicine, industry and analytical practice. Using of soluble enzymes is connected with many difficulties, because the enzymes are no regenerative and they are instability. By immobilization of the enzymes on to different carriers the more of these problems are overcome. The application of soluble enzymes caused many difficulties, by the reason that the enzymes can not be regenerated. The immobilization of the enzymes by means of different reagents and carriers overcomes this problem. The aim of this study to develop a sol-gel method of synthesis of new hybrid membrane, with immobilized biocatalysts (microbial cells and enzymes for biosensor construction. This study shows that hybrid organic-inorganic membranes were synthesized.

  13. Simultaneous immobilization of ammonium and phosphate from aqueous solution using zeolites synthesized from fly ashes.

    Science.gov (United States)

    Ji, X D; Zhang, M L; Ke, Y Y; Song, Y C

    2013-01-01

    Zeolites were synthesized from silica-rich (SF-Z) and calcium-rich (CF-Z) fly ashes, respectively, and their performance in immobilizing ammonium and phosphate was investigated through batch experiments. The cation exchange capacity and phosphate immobilization capacity of SF-Z were identified as 2.79 meq/g and 12.97 mg/g while those of CF-Z were 0.69 meq/g and 87.41 mg/g, respectively. The mixture of SF-Z and CF-Z (MSC-Z) immobilized simultaneously ammonium and phosphate, and the ratio of SF-Z to CF-Z depended on the ammonium and phosphate concentrations in wastewater and the discharge standard. The adsorption processes of ammonium and phosphate on MSC-Z followed Ho's pseudo-second-order model and the intra-particle diffusion was a rate-controlling step. The Langmuir model produced better suitability to the equilibrium data. The thermodynamic study revealed that the adsorption of both ammonium and phosphate on MSC-Z was an endothermic reaction. After treatment by MSC-Z, the ammonium and phosphate concentrations in wastewater from a sewage treatment plant decreased from 7.45 and 1.42 mg/L to 2.06 and 0.51 mg/L, respectively, and met Surface Water Environment Quality Standard in China δ. These results show that the immobilization of ammonium and phosphate in wastewater can be achieved by the combination of zeolites synthesized from silica-rich and calcium-rich fly ashes.

  14. Bentonite-Clay Waste Form for the Immobilization of Cesium and Strontium from Fuel Processing Waste Streams

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael D. [Argonne National Lab. (ANL), Argonne, IL (United States); Mertz, Carol J. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-01

    The physical properties of a surrogate waste form containing cesium, strontium, rubidium, and barium sintered into bentonite clay were evaluated for several simulant feed streams: chlorinated cobalt dicarbollide/polyethylene glycol (CCD-PEG) strip solution, nitrate salt, and chloride salt feeds. We sintered bentonite clay samples with a loading of 30 mass% of cesium, strontium, rubidium, and barium to a density of approximately 3 g/cm3. Sintering temperatures of up to 1000°C did not result in volatility of cesium. Instead, there was an increase in crystallinity of the waste form upon sintering to 1000ºC for chloride- and nitrate-salt loaded clays. The nitrate salt feed produced various cesium pollucite phases, while the chloride salt feed did not produce these familiar phases. In fact, many of the x-ray diffraction peaks could not be matched to known phases. Assemblages of silicates were formed that incorporated the Sr, Rb, and Ba ions. Gas evolution during sintering to 1000°C was significant (35% weight loss for the CCD-PEG waste-loaded clay), with significant water being evolved at approximately 600°C.

  15. Solvent-free synthesis and application of nano-Fe/Ca/CaO/[PO{sub 4}] composite for dual separation and immobilization of stable and radioactive cesium in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Mallampati, Srinivasa Reddy, E-mail: srireddys@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749 (Korea, Republic of); Mitoma, Yoshiharu, E-mail: mitomay@pu-hiroshima.ac.jp [Department of Environmental Sciences, Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, 562 Nanatsuka-Cho Shobara City, Hiroshima 727-0023 (Japan); Okuda, Tetsuji [Environmental Research and Management Center, Hiroshima University, 1-5-3 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8513 (Japan); Simion, Cristian [Politehnica University of Bucharest, Department of Organic Chemistry, Bucharest 060042 (Romania); Lee, Byeong Kyu [Department of Civil and Environmental Engineering, University of Ulsan, Daehak-ro 93, Nam-gu, Ulsan 680-749 (Korea, Republic of)

    2015-10-30

    Graphical abstract: A possible pathway for immobilization with the nano-Fe/Ca/CaO/[PO{sub 4}] treatment (a) {sup 133}Cs is adsorbed onto the soil particles, (b) Cs encapsulation through the formation of immobile salts, and (c) solid (small/finer or larger/aggregate) soil fraction separation. - Highlights: • Nano-Fe/Ca/CaO/[PO{sub 4}] composite for Cs immobilization in soil was developed. • Enhanced cesium separation and immobilization was done in dry condition. • By SEM analysis the amount of cesium detectable on soil particle surface decreases. • Leachable cesium concentrations reduced, lower than the standard regulatory limit. • Nano-Fe/Ca/CaO/[PO{sub 4}] a highly potential amendment for the remediation of Cs. - Abstract: This study assessed the synthesis and application of nano-Fe/Ca/CaO-based composite material for use as a separation and immobilizing treatment of dry soil contaminated by stable ({sup 133}Cs) and radioactive cesium species ({sup 134}Cs and {sup 137}Cs). After grinding with nano-Fe/CaO, nano-Fe/Ca/CaO, and nano-Fe/Ca/CaO/[PO{sub 4}], approximately 31, 25, and 22 wt% of magnetic fraction soil was separated. Their resultant {sup 133}Cs immobilization values were about 78, 81, and 100%, respectively. When real radioactive cesium contaminated soil obtained from Fukushima was treated with nano-Fe/Ca/CaO/[PO{sub 4}], approximately 27.3 wt% of magnetic and 72.75% of non-magnetic soil fractions were separated. The highest amount of entrapped {sup 134}Cs and {sup 137}Cs was found in the lowest weight of the magnetically separated soil fraction (i.e., 80% in 27.3% of treated soil). Results show that {sup 134}Cs and {sup 137}Cs either in the magnetic or non-magnetic soil fractions was 100% immobilized. The morphology and mineral phases of the nano-Fe/Ca/CaO/[PO{sub 4}] treated soil were characterized using SEM–EDS, EPMA, and XRD analysis. The EPMA and XRD patterns indicate that the main fraction of enclosed/bound materials on treated soil

  16. Prussian blue caged in spongiform adsorbents using diatomite and carbon nanotubes for elimination of cesium.

    Science.gov (United States)

    Hu, Baiyang; Fugetsu, Bunshi; Yu, Hongwen; Abe, Yoshiteru

    2012-05-30

    We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent.

  17. Prussian blue caged in spongiform adsorbents using diatomite and carbon nanotubes for elimination of cesium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Baiyang [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Fugetsu, Bunshi, E-mail: hu@ees.hokudai.ac.jp [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Yu, Hongwen [Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810 (Japan); Abe, Yoshiteru [Kyoei Engineering Corporation, Niigata 959-1961 (Japan)

    2012-05-30

    Highlights: Black-Right-Pointing-Pointer Prussian blue was sealed in cavities of diatomite using carbon nanotubes. Black-Right-Pointing-Pointer The caged Prussian blue after being permanently immobilized in polyurethane spongy showed a 167 mg/g capability for absorbing cesium. Black-Right-Pointing-Pointer Cesium elimination was accomplished by simply adding the Prussian-blue based spongiform adsorbent to radioactive water. - Abstract: We developed a spongiform adsorbent that contains Prussian blue, which showed a high capacity for eliminating cesium. An in situ synthesizing approach was used to synthesize Prussian blue inside diatomite cavities. Highly dispersed carbon nanotubes (CNTs) were used to form CNT networks that coated the diatomite to seal in the Prussian blue particles. These ternary (CNT/diatomite/Prussian-blue) composites were mixed with polyurethane (PU) prepolymers to produce a quaternary (PU/CNT/diatomite/Prussian-blue), spongiform adsorbent with an in situ foaming procedure. Prussian blue was permanently immobilized in the cell walls of the spongiform matrix and preferentially adsorbed cesium with a theoretical capacity of 167 mg/g cesium. Cesium was absorbed primarily by an ion-exchange mechanism, and the absorption was accomplished by self-uptake of radioactive water by the quaternary spongiform adsorbent.

  18. Solvent-free synthesis and application of nano-Fe/Ca/CaO/[PO4] composite for dual separation and immobilization of stable and radioactive cesium in contaminated soils.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Simion, Cristian; Lee, Byeong Kyu

    2015-10-30

    This study assessed the synthesis and application of nano-Fe/Ca/CaO-based composite material for use as a separation and immobilizing treatment of dry soil contaminated by stable ((133)Cs) and radioactive cesium species ((134)Cs and (137)Cs). After grinding with nano-Fe/CaO, nano-Fe/Ca/CaO, and nano-Fe/Ca/CaO/[PO4], approximately 31, 25, and 22 wt% of magnetic fraction soil was separated. Their resultant (133)Cs immobilization values were about 78, 81, and 100%, respectively. When real radioactive cesium contaminated soil obtained from Fukushima was treated with nano-Fe/Ca/CaO/[PO4], approximately 27.3 wt% of magnetic and 72.75% of non-magnetic soil fractions were separated. The highest amount of entrapped (134)Cs and (137)Cs was found in the lowest weight of the magnetically separated soil fraction (i.e., 80% in 27.3% of treated soil). Results show that (134)Cs and (137)Cs either in the magnetic or non-magnetic soil fractions was 100% immobilized. The morphology and mineral phases of the nano-Fe/Ca/CaO/[PO4] treated soil were characterized using SEM-EDS, EPMA, and XRD analysis. The EPMA and XRD patterns indicate that the main fraction of enclosed/bound materials on treated soil included Ca/PO4 associated crystalline complexes. These results suggest that simple grinding treatment with nano-Fe/Ca/CaO/[PO4] under dry conditions might be an extremely efficient separation and immobilization method for radioactive cesium contaminated soil.

  19. Synthesis and characterization of cesium molybdo vanado phosphate immobilized on platelet SBA-15: An efficient inorganic composite ion-exchanger for gadolinium ion sorption

    Energy Technology Data Exchange (ETDEWEB)

    Aghayan, H., E-mail: hasanaghayan@yahoo.com [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of); Khanchi, A.R., E-mail: akhanchi@aeoi.org.ir [Nuclear Science and Technology Institute, P.O. Box. 11365-8486, Tehran (Iran, Islamic Republic of); Mahjoub, A.R. [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of)

    2013-06-01

    A series of cesium molybdo vanado phosphate (CsMVP) supported on platelet SBA-15 (SBA-15–%xCsMVP, x = 20, 30, 40 and 50 wt.%) was synthesized to develop an efficient inorganic composite ion-exchanger for gadolinium ion removal from aqueous solution. The preparation has been carried out using two-step aqueous impregnation methods. The obtained products were characterized by inductively coupled plasma (ICP), XRD, N{sub 2} adsorption–desorption isotherms, scanning electron microscopy (SEM) and FT-IR. In order to examine adsorption behavior of this compound on gadolinium removal, the effect of heteropoly metalate loading, pH, contact time, concentration of metal ion and temperature were investigated under batch system conditions. The SBA-15–30%CsMVP showed maximum adsorption capacity toward gadolinium removal. The results suggested that this methodology provides the general synthesis of supported heteropolymetalate with large surface areas, and ordered nano porous structures that can be used as inorganic composite ion-exchanger for efficient removal of gadolinium ions from aqueous solution.

  20. Immobilization of glucose isomerase onto radiation synthesized P(AA-co-AMPS hydrogel and its application

    Directory of Open Access Journals (Sweden)

    H. Kamal

    2014-04-01

    Full Text Available Isomerization of glucose to fructose was carried out using Glucose isomerase (GI that immobilized by entrapment into Poly(acrylic acid P(AA and Poly(acrylic acid-co-2-Acrylamido 2-methyl Propane sulfonic acid P(AA-co-AMPS polymer networks, the enzyme carriers were prepared by radiation induced copolymerization in the presence of (Methylene-bisacrylamide (MBAA as a crosslinking agent. The maximum gel fraction of pure P(AA and P(AA-co-AMPS hydrogel was found to be 95.2% and 89.6% for P(AA and P(AA-co-AMPS, respectively at a total dose of 20 kGy. Effects of immobilization conditions such as radiation dose, MBAA concentration, comonomer composition and amount of GI were investigated. The influence of reaction conditions on the activity of immobilized GI were studied, the optimum pH value of the reaction solution is 7.5 and reaction temperature is 65 °C. The immobilized GI into P(AA-co-AMPS and P(AA polymer networks retained 81% and 69%, respectively of its initial activity after recycled for 15 times while it retained 87% and 71%, respectively of its initial activity after stored at 4 °C for 48 days. The Km values of free and immobilized GI onto P(AA-co-AMPS and onto P(AA matrices were found to be 34, 29.2 and 14.5 mg/mL, respectively while the Vmax Values calculated to be 3.87, 1.6 and 0.79 mg/mL min, respectively. GI entrapped into P(AA-co-AMPS hydrogel show promising behavior that may be useful as the newly glucose isomerase reactor in biomedical applications.

  1. Immobilization of heavy metals in polluted soils by the addition of zeolitic material synthesized from coal fly ash.

    Science.gov (United States)

    Querol, Xavier; Alastuey, Andrés; Moreno, Natàlia; Alvarez-Ayuso, Esther; García-Sánchez, Antonio; Cama, Jordi; Ayora, Carles; Simón, Mariano

    2006-01-01

    The use of zeolitic material synthesized from coal fly ash for the immobilization of pollutants in contaminated soils was investigated in experimental plots in the Guadiamar Valley (SW Spain). This area was affected by a pyrite slurry spill in April 1998. Although reclamation activities were completed in a few months, residual pyrite slurry mixed with soil accounted for relatively high leachable levels of trace elements such as Zn, Pb, As, Cu, Sb, Co, Tl and Cd. Phytoremediation strategies were adopted for the final recovery of the polluted soils. The immobilization of metals had previously been undertaken to avoid leaching processes and the consequent groundwater pollution. To this end, 1100 kg of high NaP1 (Na6[(AlO2)6(SiO2)10] .15H2O) zeolitic material was synthesized using fly ash from the Teruel power plant (NE Spain), in a 10 m3 reactor. This zeolitic material was manually applied using different doses (10000-25000 kg per hectare), into the 25 cm topsoil. Another plot (control) was maintained without zeolite. Sampling was carried out 1 and 2 years after the zeolite addition. The results show that the zeolitic material considerably decreases the leaching of Cd, Co, Cu, Ni, and Zn. The sorption of metals in soil clay minerals (illite) proved to be the main cause contributing to the immobilization of these pollutants. This sorption could be a consequence of the rise in pH from 3.3 to 7.6 owing to the alkalinity of the zeolitic material added (caused by traces of free lime in the fly ash, or residual NaOH from synthesis).

  2. Synergistically strengthened 3D micro-scavenger cage adsorbent for selective removal of radioactive cesium

    Science.gov (United States)

    Jang, Sung-Chan; Kang, Sung-Min; Haldorai, Yuvaraj; Giribabu, Krishnan; Lee, Go-Woon; Lee, Young-Chul; Hyun, Moon Seop; Han, Young-Kyu; Roh, Changhyun; Huh, Yun Suk

    2016-12-01

    A novel microporous three-dimensional pomegranate-like micro-scavenger cage (P-MSC) composite has been synthesized by immobilization of iron phyllosilicates clay onto a Prussian blue (PB)/alginate matrix and tested for the removal of radioactive cesium from aqueous solution. Experimental results show that the adsorption capacity increases with increasing the inactive cesium concentration from 1 ppm to 30 ppm, which may be attributed to greater number of adsorption sites and further increase in the inactive cesium concentration has no effect. The P-MSC composite exhibit maximum adsorption capacity of 108.06 mg of inactive cesium per gram of adsorbent. The adsorption isotherm is better fitted to the Freundlich model than the Langmuir model. In addition, kinetics studies show that the adsorption process is consistent with a pseudo second-order model. Furthermore, at equilibrium, the composite has an outstanding adsorption capacity of 99.24% for the radioactive cesium from aqueous solution. This may be ascribed to the fact that the AIP clay played a substantial role in protecting PB release from the P-MSC composite by cross-linking with alginate to improve the mechanical stability. Excellent adsorption capacity, easy separation, and good selectivity make the adsorbent suitable for the removal of radioactive cesium from seawater around nuclear plants and/or after nuclear accidents.

  3. Immobilization of glucose isomerase onto radiation synthesized P(AA-co-AMPS) hydrogel and its application

    OpenAIRE

    2014-01-01

    Isomerization of glucose to fructose was carried out using Glucose isomerase (GI) that immobilized by entrapment into Poly(acrylic acid) P(AA) and Poly(acrylic acid-co-2-Acrylamido 2-methyl Propane sulfonic acid) P(AA-co-AMPS) polymer networks, the enzyme carriers were prepared by radiation induced copolymerization in the presence of (Methylene-bisacrylamide) (MBAA) as a crosslinking agent. The maximum gel fraction of pure P(AA) and P(AA-co-AMPS) hydrogel was found to be 95.2% and 89.6% for P...

  4. Cell debris self-immobilized thermophilic lipase: a biocatalyst for synthesizing aliphatic polyesters.

    Science.gov (United States)

    Sun, Yang; Yang, Yan; Wang, Chenhui; Liu, Jiaming; Shi, Wei; Zhu, Xiaobo; Lu, Laijin; Li, Quanshun

    2013-05-01

    The paper explored the catalytic activity of a cell debris self-immobilized thermophilic lipase for polyester synthesis, using the ring-opening polymerization of ε-caprolactone as model. Effects of biocatalyst concentration, temperature, and reaction medium on monomer conversion and product molecular weight were systematically evaluated. The biocatalyst displayed high catalytic activity at high temperatures (70-90 °C), with 100 % monomer conversion. High monomer conversion values (>90 %) were achieved in both hydrophobic and hydrophilic solvents, and also in solvent-free system, with the exception of dichloromethane. Poly(ε-caprolactone) was obtained in 100 % monomer conversion, with a number-average molecular weight of 1,680 g/mol and a polydispersity index of 1.35 in cyclohexane at 70 °C for 72 h. Furthermore, the biocatalyst exhibited excellent operational stability, with monomer conversion values exceeding 90 % over the course of 15 batch reactions.

  5. Copper Ferrocyanide-Functionalized Magnetic Adsorbents Using Polyethyleneimine Coated Fe3O4 Nanoparticles for the Removal of Radioactive Cesium.

    Science.gov (United States)

    Yang, Hee-Man; Hong, Sang Bum; Cho, Yong Suk; Lee, Kune-Woo; Seo, Bum-Kyoung; Moon, Jei-Kwon

    2016-03-01

    Copper ferrocyanide-functionalized magnetic nano-adsorbents were successfully synthesized by electrostatic coating of citric acid coated Fe3O4 nanoparticles with polyethyleneimine, and immobilizing copper and ferrocyanide on the surfaces of polyethyleneimine-coated nanoparticles. Radioactive cesium (Cs) adsorption tests were conducted to investigate the effectiveness of the copper ferrocyanide-functionalized magnetic nano-adsorbents toward the removal of radioactive Cs.

  6. Phyto-crystallization of silver and gold by Erigeron annuus (L. Pers flower extract and catalytic potential of synthesized and commercial nano silver immobilized on sodium alginate hydrogel

    Directory of Open Access Journals (Sweden)

    Palanivel Velmurugan

    2016-05-01

    Full Text Available A green, eco-friendly approach for the synthesis of silver and gold nanoparticles (AgNPs and AuNPs using Erigeron annuus (L. pers flower extract as both the reducing and capping agent is reported for the first time. Optimal nanoparticle production was achieved by adjusting various parameters including pH, extract concentration, metal ion concentration, and time. Initial verification of AgNP and AuNP production was done by visual observation and measuring surface plasmon spectra at 434 and 537 nm, respectively. The synthesized AgNPs and AuNPs were characterized by high resolution-transmission electron microscopy (HR-TEM, X-ray diffraction (XRD, energy dispersive spectrophotometry (EDS, Fourier transform infrared spectroscopy (FTIR and zeta potential. The catalytic potential of E. annuus flower extract, silver ions, synthesized AgNPs, commercial grade AgNPs, and a mixture of flower extract and AgNPs immobilized on sodium alginate hydrogel beads (Na/Al HB was analyzed. The ability of these immobilized materials to degrade methylene blue was investigated. Commercial grade AgNPs immobilized with Na/Al HB 1.5 g/20 mL were observed to have good catalytic activity followed by a mixture of synthesized AgNPs immobilized with Na/Al HB and E. annuus flower extract immobilized with Na/Al HB at 1.5 g/20 mL.

  7. Effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper in synthesized Fe(III) minerals and Fe-rich soils.

    Science.gov (United States)

    Hu, Chaohua; Zhang, Youchi; Zhang, Lei; Luo, Wensui

    2014-04-01

    The effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper were investigated in a high concentration of sulfate with synthesized Fe(III) minerals and red earth soils rich in amorphous Fe (hydr)oxides. Batch microcosm experiments showed that red earth soil inoculated with subsurface sediments had a faster Fe(III) bioreduction rate than pure amorphous Fe(III) minerals and resulted in quicker immobilization of Cu in the aqueous fraction. Coinciding with the decrease of aqueous Cu, SO4(2-) in the inoculated red earth soil decreased acutely after incubation. The shift in the microbial community composite in the inoculated soil was analyzed through denaturing gradient gel electrophoresis. Results revealed the potential cooperative effect of microbial Fe(III) reduction and sulfate reduction on copper immobilization. After exposure to air for 144 h, more than 50% of the immobilized Cu was remobilized from the anaerobic matrices; aqueous sulfate increased significantly. Sequential extraction analysis demonstrated that the organic matter/sulfide-bound Cu increased by 52% after anaerobic incubation relative to the abiotic treatment but decreased by 32% after oxidation, indicating the generation and oxidation of Cu-sulfide coprecipitates in the inoculated red earth soil. These findings suggest that the immobilization of copper could be enhanced by mediating microbial Fe(III) reduction with sulfate reduction under anaerobic conditions. The findings have an important implication for bioremediation in Cucontaminated and Fe-rich soils, especially in acid-mine-drainage-affected sites.

  8. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    Energy Technology Data Exchange (ETDEWEB)

    ElKaoutit, Mohammed, E-mail: elkaoutit@uca.es [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Naranjo-Rodriguez, Ignacio [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Dominguez, Manuel [Departamento de Fisica de la Materia Condensada, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain); Hidalgo-Hidalgo-de-Cisneros, Jose Luis [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Cadiz, 11510 Puerto Real, Cadiz (Spain)

    2011-10-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its 'native' state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  9. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol) for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    OpenAIRE

    Huang, Y.F.; Zhang, M. Q.; M. Z. Rong; W. H. Ruan

    2017-01-01

    Polymer electrolyte membranes (PEMs) are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF) in graphene oxide/poly(vinyl alcohol) (GO/PVA) to prepare a PEM is put forward. Chemic...

  10. Synthesis of Iron-ferrocyanide functionalized magnetic nanocluster for the removal of cesium

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hee-Man; Jang, Sung-Chan; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    In the present study, magnetite nanocluster was synthesized by hydrothermal method, and coated with iron ferrocyanide for the adsorption of cesium in an aqueous solution through simple addition of iron ferrocyanide in acid condition. We describe the morphology, structure, and physical property of these nanoparticles. In addition, their ability to eliminate cesium from water was also evaluated. In this study, we fabricated Iron ferrocyanide immobilized magnetite nanocluster (IFC-MNC) using hydrothermal methods. The CIFC-MNC exhibited easy separation ability from water by an external magnet, and showed a high removal efficiency of cesium in aqueous solutions. Therefore, the IFC-MNC demonstrated good potential for the treatment of water contaminated with radioactive cesium. gnetic nanoadsorbents composed of a magnetic particles core and functional shell, which adsorb the contaminants, has attracted significant attention in environmental remediation owing to their high surface area and unique superparamagnetism. The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment. Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. Among various adsorbents to treat Cs-137 contaminated water, metal ferrocyanides were widely applied to remove the Cs-137 in water. For better separation of metal ferrocyanide from water, recently, our group reported the fabrication of copper ferrocyanide-functionalized magnetic nanoparticles (Cu-FC-EDA-MNPs) using alkoxysilanes, having ethylenediamine (EDA) group, modified Fe{sub 3}O{sub 4} nanoparticles (EDA-MNPs) for the fast and easy magnetic separation of metal ferrocyanide. However, the fabrication method was multistep procedure. Thus, a more simplified fabrication procedure is still desired.

  11. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Y. F. Huang

    2017-01-01

    Full Text Available Polymer electrolyte membranes (PEMs are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF in graphene oxide/poly(vinyl alcohol (GO/PVA to prepare a PEM is put forward. Chemical structure of the PEM is firstly characterized by 1H-, 11B- and 19F-nuclear magnetic resonance spectra, and Fourier transform infrared spectroscopy spectra, respectively, and then is further investigated under consideration of the interactions among PVA, B-PEG and LiF components. The immobilization of B-PEG/LiF in PVA-based structure is confirmed. As the interactions within electrolyte components can be further tuned by GO, ionic conductivity (~10–3 S·cm–1, lithium-ion transfer number (~0.49, and thermal (~273 °C/electrochemical (>4 V stabilities of the PEM can be obtained, and the feasibility of PEMs applied in a lithium-ion battery is also confirmed. It is believed that such PEM is a promising candidate as a new battery separator.

  12. Novel comb-type hydrogels of net-[PP-g-AAc]-g-4VP synthesized by gamma radiation, with possible application on Cu{sup 2+} immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Lazo, L.M. [Facultad de Quimica, Departamento de Ingenieria Quimica, Universidad Nacional Autonoma de Mexico (Mexico); Burillo, G., E-mail: burillo@nucleares.unam.m [Departamento de Quimica de Radiaciones y Radioquimica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico 04510 D.F. (Mexico)

    2010-01-15

    A novel comb-type grafted hydrogel system of net-[PP-g-AAc]-g-4VP was synthesized by gamma radiation in three steps. In the first step a pH sensitive graft copolymer of AAc onto PP film was obtained by radiation grafting of acrylic acid (AAc) onto polypropylene (PP) films in aqueous solution at radiation doses of 10 kGy with a {sup 60}Co source. The grafted side chains of poly (acrylic acid) (PAAc) were then cross-linked with gamma radiation at different radiation doses to give net-[PP-g-AAc]. Finally, 4-vinylpyridine (4VP) was grafted into the net-[PP-g-AAc]. The comb-type grafted hydrogel obtained, net-[PP-g-AAc]-g-4VP, has been studied through determination of graft yield and swelling behavior at room temperature. Two critical pH values were found for net-[PP-g-AAc]-g-4VP at 4.5 and 7.2. Initial studies on the immobilization of Cu{sup 2+} ions from solution into net-[PP-g-AAc]-g-4VP films were performed. The comb-type grafted hydrogel, grafted onto PP was also characterized by differential scanning calorimetry (DSC), scanning electronic microscopy (SEM) and FTIR-ATR.

  13. Engineered Materials for Cesium and Strontium Storage Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sean M. McDeavitt

    2010-04-14

    Closing the nuclear fuel cycle requires reprocessing spent fuel to recover the long-lived components that still have useful energy content while immobilizing the remnant waste fission products in stable forms. At the genesis of this project, next generation spent fuel reprocessing methods were being developed as part of the U.S. Department of Energy's Advanced Fuel Cycle Initiative. One of these processes was focused on solvent extraction schemes to isolate cesium (Cs) and strontium (Sr) from spent nuclear fuel. Isolating these isotopes for short-term decay storage eases the design requirements for long-term repository disposal; a significant amount of the radiation and decay heat in fission product waste comes from Cs-137 and Sr-90. For the purposes of this project, the Fission Product Extraction (FPEX) process is being considered to be the baseline extraction method. The objective of this project was to evaluate the nature and behavior of candidate materials for cesium and strontium immobilization; this will include assessments with minor additions of yttrium, barium, and rubidium in these materials. More specifically, the proposed research achieved the following objectives (as stated in the original proposal): (1) Synthesize simulated storage ceramics for Cs and Sr using an existing labscale steam reformer at Purdue University. The simulated storage materials will include aluminosilicates, zirconates and other stable ceramics with the potential for high Cs and Sr loading. (2) Characterize the immobilization performance, phase structure, thermal properties and stability of the simulated storage ceramics. The ceramic products will be stable oxide powders and will be characterized to quantify their leach resistance, phase structure, and thermophysical properties. The research progressed in two stages. First, a steam reforming process was used to generate candidate Cs/Sr storage materials for characterization. This portion of the research was carried out at

  14. Cesium chloride: preventive medicine for radioactive cesium exposure?

    Science.gov (United States)

    Braverman, E R; Sohler, A; Pfeiffer, C C

    1988-06-01

    Cesium is produced in high yield fission of uranium and plutonium. Radioactive cesium needles are a radiation hazard for radiotherapists. In this age of nuclear reactors, i.e. Chernobyl, radioactive cesium exposure may be a growing problem. Furthermore, there are numerous therapeutic potentials for cesium therapy, i.e. cancer, depression and schizophrenia. We explored the clearance of cesium in man and found that an oral dose of 50 mg maintains elevated blood cesium levels for 80 days. Cesium is accumulated mainly in the red blood cell fraction. Larger doses (6-9 grams) produce no observed harmful effects and maintain elevated blood levels of cesium for more than a year. Our data suggests there is a threshold of maximum cesium saturation in blood; if maintained, any additional cesium exposure, i.e. radioactive cesium, would be excreted at a more rapid rate. It is probable that large cesium doses can protect against radiation toxicity by blocking sites on red blood cells and thereby result in increased excretion and clearance of the radioactive forms of cesium. This hypothesis should be easily testable in laboratory animals.

  15. Cesium leaching from {gamma}-irradiated CsA and CsX zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Enrique [Universidad Autonoma Metropolitana, Iztapalapa, A. P. 55-532, Av. San Rafael Atlixco No. 186 Col. Vicentina, 09340 Mexico, D.F. (Mexico)], E-mail: lima@xanum.uam.mx; Ibarra, Ilich A.; Lara, Victor [Universidad Autonoma Metropolitana, Iztapalapa, A. P. 55-532, Av. San Rafael Atlixco No. 186 Col. Vicentina, 09340 Mexico, D.F. (Mexico); Bosch, Pedro [Instituto de Investigaciones en Materiales, A. P. 70-360, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510 Mexico, D.F. (Mexico); Bulbulian, Silvia [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, 11801 Mexico, D.F. (Mexico)

    2008-12-30

    The present study discusses the effect of {gamma}-irradiation on Cs{sup +}-exchanged X and A zeolites. The incorporation of Cs{sup +} ions into A and X zeolites was performed using three different cesium salts (chloride, nitrate or acetate). Cs{sup +} ions immobilized into the vitrified zeolites by thermal treatment are located in different sites of the zeolite networks. It is found that {gamma}-irradiation favors cesium retention depending on the cesium precursor salt used in the cationic exchange step.

  16. Immobilization of fission products in phosphate ceramic waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D. [Argonne National Lab., IL (United States)

    1996-10-01

    The goal of this project is to develop and demonstrate the feasibility of a novel low-temperature solidification/stabilization (S/S) technology for immobilizing waste streams containing fission products such as cesium, strontium, and technetium in a chemically bonded phosphate ceramic. This technology can immobilize partitioned tank wastes and decontaminate waste streams containing volatile fission products.

  17. Status of plutonium ceramic immobilization processes and immobilization forms

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.B.; Van Konynenburg, R.A. [Lawrence Livermore National Lab., CA (United States); Vance, E.R.; Jostsons, A. [Australian Nuclear Science and Technology Organization, Menai (Australia)] [and others

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  18. Study on Technology of Synthesizing Theaflavins through Enzyme-catalysing Oxidation with Immobilized Laccase%固定化漆酶酶促合成茶黄素工艺的研究

    Institute of Scientific and Technical Information of China (English)

    岳鹍; 揣玉多; 孙勇民

    2011-01-01

    [目的]探索固定化漆酶酶促合成茶黄素的工艺.[方法]采用D152树脂固定化漆酶体外酶促氧化茶多酚合成茶黄素.通过单因素试验研究反应温度、pH、酶浓度、反应时间和通氧量对合成茶黄素的影响,在此基础上进行茶黄素的酶促氧化合成反应,之后测定茶黄素产量.[结果]采用树脂载体D152固定化得到的固定化漆酶,在重复使用5次后,固定化漆酶催化活性约为原始催化活性的70%;在重复使用10次后,酶催化活性仍然可以保留48%左右.固定化漆酶促氧化的最佳条件为:反应温度60 ℃,最佳pH 5,底物浓度2.0g/L,通氧量20 L/min和反应时间1.5h.[结论]采用树脂载体D152可有效固定漆酶.与游离漆酶氧化法相比,固定化法能有效提高漆酶的稳定性和利用效率,反应产物也更易于纯化.%[Objective ] The study aimed to explore the technology of synthesizing the theaflavins through the enzyme-catalysing oxidation with the immobilized laccase. [Method] The theaflavins was synthesized from tea polyphenol through in vitro enzyme-catalysing oxidation with D152 resin immobilized laccase. The effects of the reaction temperature, pH value, enzyme concn. , reaction time and speed of adding oxygen on synthesizing the theaflavins was studied though the single factor experiment, on base of which, the synthesizing reaction through the enzyme-catalysing oxidation was conducted on the theaflavins and then the yield of the theaflavins was determined. [Result] The immobilized laccase was got by the immobilization with the resin carrier D152,the enzyme-catalysing activity by the immobilized laccase was about 70% of the original catalytic activity after the repetition use of the resin for 5 times and that still retained 48% or so after the repetition use for 10 times. The best conditions for the enzyme-catalysing oxidation with the immobilized laccase were as followsjthe reaction temperature of 60 ℃ ,best pH value of 5

  19. Synthesis of novel calix[4]crown telomers and selective extraction of cesium ions

    Institute of Scientific and Technical Information of China (English)

    Hai Bing Li; Yuan Yin Chen; De Jun Xiong; Jun Yan Zhan; Cui Ping Han

    2007-01-01

    p-tert-Butylcalix[4]diazacrown-4 telomer, which contains hard and soft ion binding sites, was synthesized. It exhibited high selectivity toward cesium ions. The binding sites may complex alkali metal ions selectively.

  20. CAFS: A Cesium Atomic Frequency Standard for GPS block IIR

    Science.gov (United States)

    Wisnia, Jeffry A.

    1993-01-01

    Kernco, Inc. was selected to design the Cesium Atomic Frequency Standards (CAFS) for the GPS Block IIR NAVSTAR satellites. These spacecraft are scheduled to be launched in the mid-1990's to replenish and upgrade the existing constellation of Global Positioning System satellites. The Block IIR CAFS output frequency is 13.4003378 MHz, the 686th submultiple of the cesium atomic resonance frequency. Using an integer submultiple simplifies the design of the atomic frequency standard's rf multiplier circuits, eliminating the secondary frequency synthesizer needed in previous designs. The GPS Block IIR CAFS design, particularly the improvements made on our earlier Block II design is described. Test results are included.

  1. Clinical effects of cesium intake.

    Science.gov (United States)

    Melnikov, Petr; Zanoni, Lourdes Zélia

    2010-06-01

    The knowledge about cesium metabolism and toxicity is sparse. Oral intake of cesium chloride has been widely promoted on the basis of the hypothesis referred to as "high pH cancer therapy", a complimentary alternative medicine method for cancer treatment. However, no properly confirmed tumor regression was reported so far in all probability because of neither theoretical nor experimental grounds for this proposal. The aim of the present review was to resume and discuss the material currently available on cesium salts and their applications in medicine. The presence of cesium in the cell does not guarantee high pH of its content, and there is no clinical evidence to support the claims that cancer cells are vulnerable to cesium. Cesium is relatively safe; signs of its mild toxicity are gastrointestinal distress, hypotension, syncope, numbness, or tingling of the lips. Nevertheless, total cesium intakes of 6 g/day have been found to produce severe hypokalemia, hypomagnesemia, prolonged QTc interval, episodes of polymorphic ventricular tachycardia, with or without torsade de pointes, and even acute heart arrest. However, full information on its acute and chronic toxicity is not sufficiently known. Health care providers should be aware of the cardiac complications, as a result of careless cesium usage as alternative medicine.

  2. Mineral resource of the month: cesium

    Science.gov (United States)

    Angulo, Marc A.

    2010-01-01

    The article offers information on cesium, a golden alkali metal derived from the Latin word caesium which means bluish gray. It mentions that cesium is the first element discovered with the use of spectroscopy. It adds that the leading producer and supplier of cesium is Canada and there are 50,000 kilograms of cesium consumed of the world in a year. Moreover, it states that only 85% of the cesium formate can be retrieved and recycled.

  3. Cesium diffusion in graphite

    Energy Technology Data Exchange (ETDEWEB)

    Evans, R.B. III; Davis, W. Jr.; Sutton, A.L. Jr.

    1980-05-01

    Experiments on diffusion of /sup 137/Cs in five types of graphite were performed. The document provides a completion of the report that was started and includes a presentation of all of the diffusion data, previously unpublished. Except for data on mass transfer of /sup 137/Cs in the Hawker-Siddeley graphite, analyses of experimental results were initiated but not completed. The mass transfer process of cesium in HS-1-1 graphite at 600 to 1000/sup 0/C in a helium atmosphere is essentially pure diffusion wherein values of (E/epsilon) and ..delta..E of the equation D/epsilon = (D/epsilon)/sub 0/ exp (-..delta..E/RT) are about 4 x 10/sup -2/ cm/sup 2//s and 30 kcal/mole, respectively.

  4. Cesium chloride-induced torsades de pointes.

    Science.gov (United States)

    Wiens, Matthew; Gordon, Wendy; Baulcomb, Daisy; Mattman, Andre; Mock, Tom; Brown, Robert

    2009-09-01

    The chloride salt of cesium, a group 1A element, is gaining popularity as an alternative treatment of advanced cancers. Cesium chloride has primarily been used in cardiovascular research for arrhythmogenesis in animals because of its potassium-blocking effects. The present report describes a 45-year-old woman with metastatic breast cancer who experienced repeated episodes of torsades de pointes polymorphic ventricular tachycardia after several months of oral cesium therapy. There was a clear temporal relationship between cesium ingestion and the arrhythmia, which later resolved following discontinuation of cesium therapy. Serial cesium plasma and whole blood levels were measured over the ensuing six months and pharmacokinetic analysis was performed.

  5. Synthesis and structural and thermodynamical characterization of hollandite type material intended for the specific containment of cesium; Synthese et caracterisation de ceramiques de type hollandite destinees au conditionnement specifique du cecium

    Energy Technology Data Exchange (ETDEWEB)

    Leinekugel-Le-Cocq-Errien, A.Y

    2005-09-15

    This thesis deals with the characterization of the Ba{sub 1}Cs{sub 0.28}Fe{sub 0.82}Al{sub 1.46}Ti{sub 5.72}O{sub 16} hollandite envisaged for Cs containment. Techniques used are essentially classical powder XRD or synchrotron radiation at the absorption threshold of Ba and Cs, TEM and high-temperature calorimetry. Two syntheses have been studied: an alcoxide route and a dry route. After sintering, both routes lead to an incommensurate modulated tetragonal hollandite structure (space group: I4/m(00{gamma})00) with a modulation vector distribution. Before sintering, the material obtained by the alcoxide route is composed of three phases: a tetragonal hollandite like above, a monoclinic Ba-free hollandite and a weak-coherence-length phase containing only Ba. On contrary, the dry route already leads to the tetragonal hollandite at this step of the synthesis. High temperature oxide melt solution calorimetry was used to derive standard enthalpy of formation of hollandite to deduce its free enthalpy of formation. (author)

  6. Morphological and electrical properties of zirconium vanadate doped with cesium

    Directory of Open Access Journals (Sweden)

    Marwa F. Elkady

    2014-09-01

    Full Text Available Cesium doped zirconium vanadate ZrV2O7 with different Cs dopant content (Cs/Zr varied from 0 to 0.5 in weight ratio were fabricated by hydrothermal technique at 120 °C for 60 min. The synthesized materials are thermally treated using microwave technique. The structural and morphological properties of the synthesized materials and thermally treated samples were investigated using XRD and SEM respectively. It was evident that all synthesized specimens have cubic phase structural without any extra phase but after heat treatment Orthorhombic phase appear with doped samples. However, the morphological structure of the doped synthesized materials has transferred from nanoparticles into rods aspect with heat treatment for the different dopant ratio. Moreover, the electrical properties of both the synthesized and thermally treated materials are studied by AC impedance measurements. The results indicated that the ionic conductivity of Cs-doped ZrV2O7 materials decreased by increasing the dopant ratio while that thermally treated samples the ionic conductivity increase by increasing the dopant ratio. Finally, the concentration of cesium dopants is found to play crucial role in tuning the morphology and electrical properties of nanostructures.

  7. Decorporation of cesium-137; Decorporation du cesium-137

    Energy Technology Data Exchange (ETDEWEB)

    Le Fleche, Ph.; Destombe, C.; Grasseau, A.; Mathieu, J.; Chancerelle, Y.; Mestries, J.C. [GMR, Direction des Recherches, Etudes et Techniques, 94 - Arcueil (France)

    1997-12-31

    Cesium radio-isotopes, especially cesium-137 ({sup 137}Cs) are among the radionuclides of main importance produced by a fission reaction in reactor or a nuclear weapon explosion. In the environment, {sup 137}Cs is a major contaminant which can cause severe {beta}, {gamma}irradiations and contaminations. {sup 137}Cs is distributed widely and relatively uniformly throughout the body with the highest concentration in skeletal muscles. A treatment becomes difficult afterwards. The purposes of this report are Firstly to compare the Prussian blue verses cobalt and potassium ferrocyanide (D.I. blue) efficiency for the {sup 137}Cs decorporation and secondly to assess a chronological treatment with D.I. blue. (author)

  8. Cesium chloride-induced torsades de pointes

    OpenAIRE

    Wiens, Matthew; Gordon, Wendy; Baulcomb, Daisy; Mattman, Andre; Mock, Tom; Brown, Robert

    2009-01-01

    The chloride salt of cesium, a group 1A element, is gaining popularity as an alternative treatment of advanced cancers. Cesium chloride has primarily been used in cardiovascular research for arrhythmogenesis in animals because of its potassium-blocking effects. The present report describes a 45-year-old woman with metastatic breast cancer who experienced repeated episodes of torsades de pointes polymorphic ventricular tachycardia after several months of oral cesium therapy. There was a clear ...

  9. CESIUM DITHIOLATE BASED SYNTHESES OF KETO-FUNCTIONALIZED THIO-CROWN ETHERS EMPLOYING THE NOVEL BUILDING-BLOCK 1,3-DIMERCAPTOACETONE - MOLECULAR-STRUCTURES OF 2,5,9,12-TETRATHIA-7-OXO-(13)-M-BENZENOPHANE AND 1,4,7,10,13-PENTATHIACYCLOHEXADECAN-15-ONE

    NARCIS (Netherlands)

    EDEMA, JJH; SCHOONBEEK, FS; MEETSMA, A; VANBOLHUIS, F; KELLOGG, RM

    1993-01-01

    Cyclization of the bis cesium thiolate (generated in situ) of 1,3-dimercaptoacetone (1) with alpha,omega-dihalides in DMF affords the corresponding cyclic thioethers in good yields, providing an efficient alternative route to keto-functionalized thio-crown ethers. A previously suggested dimeric stru

  10. Synthesis of novel calixcrown derivatives with selective complexation towards cesium ions

    Institute of Scientific and Technical Information of China (English)

    Lu Zhang; Juan Du; Li Hua Yuan; Dong Zhang; Gui Ping Dan; Yuan You Yang; Wen Feng

    2011-01-01

    A series of novel calix [4]arenecrown-6 derivatives with an alkenyl loop of various sizes 5-8 were synthesized via intramolecular ring closing olefin metathesis and characterized by 1H NMR, 13C NMR and ESI-HRMS. Their complexation property towards cesium ion was studied by 'H NMR technique. Two-phase extraction of alkali metal ions using UV-vis spectroscopy revealed remarkably different extractabilities. These results indicate that the complexation capacities towards cesium ions can be tuned and controlled through cooperative regulation of the strain of the loop and conformational change of calixcrown skelton.

  11. Continuous Separation of Cesium Based on NiHCF/PTCF Electrode by Electrochemically Switched Ion Exchange

    Institute of Scientific and Technical Information of China (English)

    孙斌; 郝晓刚; 王忠德; 张忠林; 刘世斌; 官国清

    2012-01-01

    Nickel hexacyanoferrate (NiHCF) film was synthesized on porous three-dimensional carbon felt (PTCF) substrate by repetitious batch chemical depositions, and the NiHCF/PTCF electrode was used as electrochemically switched ion exchange (ESIX) electrode in a packed bed for continuous separation for cesium ions. The morphologies of the prepared electrodes were characterized by scanning electron microscopy and the effects of solution concentration on the ion-exchange capacity of the electrodes were investigated by cyclic voltammetry technique. Cycling stability and long-term storage stability of NiHCF/PTCF electrodes were also studied. The NiHCF/PTCF electrodes with excellent ion-exchange ability were used to assemble a diaphragm-isolated ESIX reactor for cesium separation. Continuous separation of cesium and regeneration of NiHCF/PTCF electrode based on the diaphragm-isolated reactor were performed in a laboratory-scale two-electrode system.

  12. Physical barrier effect of geopolymeric waste form on diffusivity of cesium and strontium.

    Science.gov (United States)

    Jang, J G; Park, S M; Lee, H K

    2016-11-15

    The present study investigates the physical barrier effect of geopolymeric waste form on leaching behavior of cesium and strontium. Fly ash-based geopolymers and slag-blended geopolymers were used as solidification agents. The leaching behavior of cesium and strontium from geopolymers was evaluated in accordance with ANSI/ANS-16.1. The diffusivity of cesium and strontium in a fly ash-based geopolymer was lower than that in Portland cement by a factor of 10(3) and 10(4), respectively, showing significantly improved immobilization performance. The leaching resistance of fly ash-based geopolymer was relatively constant regardless of the type of fly ash. The diffusivity of water-soluble cesium and strontium ions were highly correlated with the critical pore diameter of the binder. The critical pore diameter of the fly ash-based geopolymer was remarkably smaller than those of Portland cement and slag-blended geopolymer; consequently, its ability physically to retard the diffusion of nuclides (physical barrier effect) was superior.

  13. Incorporation of cesium into phosphates of apatitic and rhabdophane lattices. Application to the conditioning of separated radionuclides; Incorporation du cesium dans des phosphates de structure apatitique et rhabdophane. Application au conditionnement des radionucleides separes

    Energy Technology Data Exchange (ETDEWEB)

    Campayo, L

    2003-04-01

    Two phosphate-based materials were investigated for cesium immobilization after its partitioning from spent nuclear fuel: apatites and rhabdophanes. The incorporation of cesium into the apatitic lattice creates steric stresses. These stresses induce the formation of secondary phases which are rapidly leached. The effectiveness of the cesium immobilization in this material is not therefore validated. A second phosphate CsCaNd(PO{sub 4}){sub 2} was consistently found at the end of the leach test and its properties were further characterized. The structure of CsCaNd(PO{sub 4}){sub 2}, which is rhabdophane-like, is made of large channels which enable the incorporation of the largest alkaline cations. The synthesis involves two intermediates: the monazite, NdPO{sub 4}, and a soluble phosphate, CsCaPO{sub 4}. The study of a rhabdophane with 10 wt.% of cesium reveals satisfactory intrinsic properties: a thermal stability up to 1100 C and a leach rate of 10{sup -2} g/(m{sup 2}.d). The next step will be to improve the reaction yield. (author)

  14. Cesium and strontium ion specific exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Yates, S.

    1996-10-01

    This work is one of two parallel projects that are part of an ESP task to develop high-capacity, selective, solid extractants for cesium, strontium, and technetium from nuclear wastes. In this subtask, Pacific Northwest National Laboratory (PNNL) is collaborating with AlliedSignal, Inc. (Des Plaines, Illinois) to develop inorganic ion exchangers that are selective for strontium and cesium from alkaline high-level waste and groundwater streams.

  15. Sugar-metal ion interactions: the complicated coordination structures of cesium ion with D-ribose and myo-inositol.

    Science.gov (United States)

    Hu, Haijian; Xue, Junhui; Wen, Xiaodong; Li, Weihong; Zhang, Chao; Yang, Limin; Xu, Yizhuang; Zhao, Guozhong; Bu, Xiaoxia; Liu, Kexin; Chen, Jia'er; Wu, Jinguang

    2013-11-18

    The novel cesium chloride-D-ribose complex (CsCl·C5H10O5; Cs-R) and cesium chloride-myo-inositol complex (CsCl·C6H12O6; Cs-I) have been synthesized and characterized using X-ray diffraction and FTIR, FIR, THz, and Raman spectroscopy. Cs(+) is eight-coordinated to three chloride ions, O1 and O2 from one D-ribose molecule, O1 from another D-ribose molecule, and O4 and O5 from the third D-ribose molecule in Cs-R. For one D-ribose molecule, the oxygen atom O1 in the ring is coordinated to two cesium ions as an oxygen bridge, O2 is cocoordinated with O1 to one of the two cesium ions, and O4 and O5 are coordinated to the third cesium ion, respectively. O3 does not coordinate to metal ions and only takes part in forming hydrogen bonds. One chloride ion is connected to three cesium ions. Thus, a complicated structure of Cs-D-ribose forms. For Cs-I, Cs(+) is 10-coordinated to three chloride ions, O1 and O2 from one myo-inositol molecule, O3 and O4 from another myo-inositol molecule, O5 and O6 from the third myo-inositol molecule, and O6 from the fourth myo-inositol molecule. One metal ion is connected to four ligands, and one myo-inositol is coordinated to four Cs(+) ions, which is also a complicated coordination structure. Crystal structure results, FTIR, FIR, THz, and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride-D-ribose and cesium chloride-myo-inositol complexes.

  16. Electrically controlled cesium ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01

    Several sites within the DOE complex (Savannah River, Idaho, Oak Ridge and Hanford) have underground storage tanks containing high-level waste resulting from nuclear engineering activities. To facilitate final disposal of the tank waste, it is advantageous to separate and concentrate the radionuclides for final immobilization in a vitrified glass matrix. This task proposes a new approach for radionuclide separation by combining ion exchange (IX) and electrochemistry to provide a selective and economic separation method.

  17. Preparation of Laccase Immobilized Cryogels and Usage for Decolorization

    Directory of Open Access Journals (Sweden)

    Murat Uygun

    2013-01-01

    Full Text Available Poly(methyl methacrylate-co-glycidyl methacrylate (poly(MMA-co-GMA cryogels were synthesized by radical cryopolymerization technique. Then, laccase enzyme was covalently attached to the cryogel and characterized by using swelling studies and SEM and EDX analyses. Kinetic properties and optimum conditions of the immobilized and free laccase were studied and it was found that of the immobilized laccase was lower than that of free laccase. of the immobilized laccase was increased upon immobilization. Optimum pH was found to be 4.0 for each type of laccase, while optimum temperature was shifted to the warmer region after the immobilization. It was also found that thermal stability of the immobilized laccase was higher than that of free laccase. Immobilized laccase could be used for 10 times successive reuse with no significant decrease in its activity. Also, these laccase immobilized cryogels were successfully used for the decolorization of seven different dyes.

  18. 40 CFR 721.10168 - Cesium tungsten oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Cesium tungsten oxide. 721.10168... Substances § 721.10168 Cesium tungsten oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as cesium tungsten oxide (PMN P-08-275; CAS No....

  19. Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium

    Science.gov (United States)

    Vipin, Adavan Kiliyankil; Fugetsu, Bunshi; Sakata, Ichiro; Isogai, Akira; Endo, Morinobu; Li, Mingda; Dresselhaus, Mildred S.

    2016-11-01

    On 11 March 2011, the day of the unforgettable disaster of the 9 magnitude Tohoku earthquake and quickly followed by the devastating Tsunami, a damageable amount of radionuclides had dispersed from the Fukushima Daiichi’s damaged nuclear reactors. Decontamination of the dispersed radionuclides from seawater and soil, due to the huge amounts of coexisting ions with competitive functionalities, has been the topmost difficulty. Ferric hexacyanoferrate, also known as Prussian blue (PB), has been the most powerful material for selectively trapping the radioactive cesium ions; its high tendency to form stable colloids in water, however, has made PB to be impossible for the open-field radioactive cesium decontamination applications. A nano/nano combinatorial approach, as is described in this study, has provided an ultimate solution to this intrinsic colloid formation difficulty of PB. Cellulose nanofibers (CNF) were used to immobilize PB via the creation of CNF-backboned PB. The CNF-backboned PB (CNF/PB) was found to be highly tolerant to water and moreover, it gave a 139 mg/g capability and a million (106) order of magnitude distribution coefficient (Kd) for absorbing of the radioactive cesium ion. Field studies on soil and seawater decontaminations in Fukushima gave satisfactory results, demonstrating high capabilities of CNF/PB for practical applications.

  20. Fire Safety Tests for Cesium-Loaded Spherical Resorcinol Formaldehyde Resin: Data Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Sang; Schweiger, Michael J.; Peterson, Reid A.

    2012-09-01

    A draft safety evaluation of the scenario for spherical resorcinol formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI) through a subcontract managed by Pacific Northwest National Laboratory (PNNL). The results of initial fire safety tests on the SRF resin were documented in a previous report (WTP-RPT-218). The present report summarizes the results of additional tests performed by SwRI on the cesium-loaded SRF resin. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. The as-received SwRI report is attached to this report in the Appendix A. Where applicable, the precision and bias of each test method, as given by each American Society for Testing and Materials (ASTM) standard procedure, are included and compared with the SwRI test results of the cesium-loaded SRF resin.

  1. Cesium Isotherm Testing with Spherical Resorcinol-Formaldehyde Resin at High Sodium Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fiskum, Sandra K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Smoot, Margaret R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rinehart, Donald E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-04-01

    Washington River Protection Solutions (WRPS) is developing a Low-Activity Waste Pretreatment System (LAWPS) to provide low-activity waste (LAW) directly to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste Facility for immobilization. The pretreatment that will be conducted on tank waste supernate at the LAWPS facility entails filtration to remove entrained solids and cesium (Cs) ion exchange to remove Cs from the product sent to the WTP. Currently, spherical resorcinol-formaldehyde (sRF) resin (Microbeads AS, Skedsmokorset, Norway) is the Cs ion exchange resin of choice. Most work on Cs ion exchange efficacy in Hanford tank waste has been conducted at nominally 5 M sodium (Na). WRPS is examining the possibility of processing supernatant at high Na concentrations—up to 8 M Na—to maximize processing efficiency through the LAWPS. Minimal Cs ion exchange work has been conducted at 6 M and 8 M Na concentrations..

  2. One Pot Synthesis and Characterization of Cesium Doped SnO2 Nanocrystals via a Hydrothermal Process

    Institute of Scientific and Technical Information of China (English)

    K. Kaviyarasu; Prem Anand Devarajan; S. Stanly John Xavier; S. Augustine Thomas; S. Se]vakumar

    2012-01-01

    The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), inductively coupled plasma (ICP), atomic absorption spectroscopic (AAS) analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.

  3. Perlite for permanent confinement of cesium

    Science.gov (United States)

    Balencie, J.; Burger, D.; Rehspringer, J.-L.; Estournès, C.; Vilminot, S.; Richard-Plouet, M.; Boos, A.

    2006-06-01

    We present the potential use of expanded perlite, a metastable amorphous hydrated aluminium silicate, as a permanent medium for the long-term confinement of cesium. The method requires simply a loading by mixing an aqueous cesium nitrate solution and expanded perlite at 300 K followed by densification by sintering. The formation of pollucite, CsAlSi2O6, a naturally occurring mineral phase, upon careful heat treatment is demonstrated by X-ray diffraction. Leaching tests on the resulting glass-ceramics reveal a very low Cs departure of 0.5 mg m-2 d-1.

  4. Crystalline silicotitanates for cesium/strontium removal

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.; Miller, J.; Sherman, J.

    1996-10-01

    A new class of inorganic ion exchangers called crystalline silicotitanates (CST) has been developed that exhibits very high selectivity for cesium and strontium in the highly alkaline radioactive wastes at the Hanford Site and other DOE sites. Tests have also shown that CSTs have high selectivity for cesium in acidic and neutral solutions. The ESP is supporting an effort at Sandia National Laboratories and Texas A & M University to further develop and characterize the important chemical and physical properties that will determine the applicability of CST to radioactive waste treatment at Hanford and other DOE facilities.

  5. Microbial accumulation of uranium, radium, and cesium

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, G.W.; Shumate, S.E. II; Parrott, J.R. Jr.; North, S.E.

    1981-05-01

    Diverse microbial species varied considerably in their ability to accumulate uranium, cesium, and radium. Mechanistic differences in uranium uptake by Saccharomyces cerevisiae and Pseudomonas aeruginosa were indicated. S. serevisiae exhibited a slow (hours) surface accumulation of uranium which was subject to environmental factors, while P. aeruginosa accumulated uranium rapidly (minutes) as dense intracellular deposits and did not appear to be affected by environmental parameters. Metabolism was not required for uranium uptake by either organism. Cesium and radium were concentrated to a considerably lesser extent than uranium by the several species tested.

  6. Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using SuperLig 644 Resin

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L.L.

    2000-08-23

    A proposed facility is being designed for the immobilization of Hanford high-level radioactive waste. One unit process in the facility is designed to remove radioactive cesium by ion-exchange from the strongly alkaline aqueous phase. A resin specifically designed with high selectivity of cesium under alkaline conditions is being investigated. The resin also is elutable under more acidic conditions. The proposed design of the facility consists of two sets of two packed columns placed in series (i.e., a lead column followed by a lag (guard) column configuration). During operation, upon reaching a specified cesium concentration criterion at the exit of the lag column, operation is switched to the second set of lead and lag columns. The cesium-loaded lead column is processed (i.e., washed and eluted) and switched to the lag position. the previous lag column is then placed in the lead position (without eluting) and the system is ready for use in the next cycle. For a well designed process, the loading and elution processes result in significant volume reductions in aqueous high-level waste.

  7. Waveform synthesizer

    Science.gov (United States)

    Franks, Larry A.; Nelson, Melvin A.

    1981-01-01

    A method of producing optical and electrical pulses of desired shape. An optical pulse of arbitrary but defined shape illuminates one end of an array of optical fiber waveguides of differing lengths to time differentiate the input pulse. The optical outputs at the other end of the array are combined to form a synthesized pulse of desired shape.

  8. Resonance Ionization Spectroscopy of Cesium Atoms in a Cesium Heat Pipe

    Science.gov (United States)

    Ardis, Robert G.; Gardner, Bernard W.; Smith, R. Seth

    1997-11-01

    A Cesium Heat Pipe has been constructed to produce a cesium metal vapor for use in laser spectroscopy. The heat pipe consists of a 24 inch stainless steel pipe with 2 inch diameter calcium fluoride windows on each end. Electric heaters are used to control the cesium vapor pressure. An argon buffer gas is used to maintain high transmittance through the end windows. Sensors are used to monitor both temperature and pressure. A Nd:YAG-pumped dye laser system is used to probe the cesium atoms via resonance ionization spectroscopy. Details of the construction of the heat pipe and the experimental setup will be presented. The results of the resonance ionization spectroscopy will be discussed. This experimental setup can be utilized with undergraduates in courses such as Optics, Laser Physics, and Senior Laboratory/Research.

  9. Cesium vapor thermionic converter anomalies arising from negative ion emission

    Science.gov (United States)

    Rasor, Ned S.

    2016-08-01

    Compelling experimental evidence is given that a longstanding limit encountered on cesium vapor thermionic energy converter performance improvement and other anomalies arise from thermionic emission of cesium negative ions. It is shown that the energy that characterizes thermionic emission of cesium negative ions is 1.38 eV and, understandably, is not the electron affinity 0.47 eV determined for the photodetachment threshold of the cesium negative ion. The experimental evidence includes measurements of collector work functions and volt-ampere characteristics in quasi-vacuum cesium vapor thermionic diodes, along with reinterpretation of the classic Taylor-Langmuir S-curve data on electron emission in cesium vapor. The quantitative effects of negative ion emission on performance in the ignited, unignited, and quasi-vacuum modes of cesium vapor thermionic converter operation are estimated.

  10. Ion exchange kinetics of cesium for various reaction designs using crystalline silicotitanate, UOP IONSIV IE-911

    Science.gov (United States)

    Kim, Sung Hyun

    Through collaborative efforts at Texas A&M University and Sandia National Laboratories, a crystalline silicotitanate (CST), which shows extremely high selectivity for radioactive cesium removal in highly concentrated sodium solutions, was synthesized. The effect of hydrogen peroxide on a CST under cesium ion exchange conditions has been investigated. The experimental results with hydrogen peroxide showed that the distribution coefficient of cesium decreased and the tetragonal phase, the major component of CST, slowly dissolved at hydrogen peroxide concentrations greater than 1 M. A simple and novel experimental apparatus for a single-layer ion exchange column was developed to generate experimental data for estimation of the intraparticle effective diffusivity. A mathematical model is presented for estimation of effective diffusivities for a single-layer column of CST granules. The intraparticle effective diffusivity for Cs was estimated as a parameter in the analytical solution. By using the least square method, the effective diffusivities of 1.56 +/- 0.14 x 10-11 m2/s and 0.68 +/- 0.09 x 10-11 m2/s, respectively, were obtained. The difference in the two values was due to the different viscosities of the solutions. A good fit of the experimental data was obtained which supports the use of the homogeneous model for this system. A counter-current ion exchange (CCIX) process was designed to treat nuclear waste at the Savannah River Site. A numerical method based on the orthogonal collocation method was used to simulate the concentration profile of cesium in the CCIX loaded with CST granules. To maximize cesium loading onto the CST and minimize the volume of CST, two design cases of a moving bed, where the fresh CST is pulsed into the column at certain periods or at certain concentration of cesium, were investigated. Simulation results showed that cesium removal behavior in the pilot-scale test of CCIX experiment, where the column length is 22 ft and the CST is pulsed

  11. Cesium and Strontium Separation Technologies Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    T. A. Todd; T. A. Todd; J. D. Law; R. S. Herbst

    2004-03-01

    Integral to the Advanced Fuel Cycle Initiative (AFCI) Program’s proposed closed nuclear fuel cycle, the fission products cesium and strontium in the dissolved spent nuclear fuel stream are to be separated and managed separately. A comprehensive literature survey is presented to identify cesium and strontium separation technologies that have the highest potential and to focus research and development efforts on these technologies. Removal of these high-heat-emitting fission products reduces the radiation fields in subsequent fuel cycle reprocessing streams and provides a significant short-term (100 yr) heat source reduction in the repository. This, along with separation of actinides, may provide a substantial future improvement in the amount of fuel that could be stored in a geologic repository. The survey and review of the candidate cesium and strontium separation technologies are presented herein. Because the AFCI program intends to manage cesium and strontium together, technologies that simultaneously separate both elements are of the greatest interest, relative to technologies that separate only one of the two elements.

  12. Nano-Cesium for Anti-Cancer Properties: An Investigation into Cesium Induced Metabolic Interference.

    Science.gov (United States)

    Daza, Enrique A; Misra, Santosh K; Schwartz-Duval, Aaron S; Ohoka, Ayako; Miller, Callie; Pan, Dipanjan

    2016-10-03

    The use of cesium chloride (CsCl) for cancer therapy ("high pH therapy") has been theorized to produce anticancer properties by raising intracellular pH to induce apoptosis. Although considered as "alternative medicine", little scientific evidence supports this theory. Alternatively, cells have no cesium ion (Cs(+)) mediated channels for clearance. Thus, such unstable electrochemical distributions have the severe potential to disrupt electrochemical dependent cellular processes, such as glucose cotransporters. Hence, a detailed investigation of pH changing effects and glucose uptake inhibition are warranted as a possible cesium-induced anticancer therapy. We developed and characterized cesium nanoparticles (38 ± 6 nm), termed NanoCs, for nanoparticle-mediated internalization of the ion, and compared its treatment to free CsCl. Our investigations suggest that neither NanoCs nor CsCl drastically changed the intracellular pH, negating the theory. Alternatively, NanoCs lead to a significant decrease in glucose uptake when compared to free CsCl, suggesting cesium inhibited glucose uptake. An apoptosis assay of observed cell death affirms that NanoCs leads tumor cells to initiate apoptosis rather than follow necrotic behavior. Furthermore, NanoCs lead to in vivo tumor regression, where H&E analysis confirmed apoptotic cell populations. Thus, NanoCs performed pH-independent anticancer therapy by inducing metabolic stasis.

  13. Cesium Atomic Fountain Clocks at NMIJ

    Science.gov (United States)

    2010-11-01

    shift in caesium fountain clocks,” Physical Review Letters, 98, 153002. [10] A. Takamizawa, Y. Shirakawa, S. Yanagimachi et al., 2010, “Proposal of a...beam of laser-cooled cesium atoms,” Physical Review, A 60, R4241-R4244. [13] V. Gerginov, N. Nemitz, S. Weyers, et al., 2010, “Uncertainty evaluation of the caesium fountain clock PTB-CSF2,” Metrologia, 47, 65-79.

  14. Lanthanide doped strontium-barium cesium halide scintillators

    Science.gov (United States)

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  15. Surface interactions of cesium and boric acid with stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Grossman-Canfield, N.

    1995-08-01

    In this report, the effects of cesium hydroxide and boric acid on oxidized stainless steel surfaces at high temperatures and near one atmosphere of pressure are investigated. This is the first experimental investigation of this chemical system. The experimental investigations were performed using a mass spectrometer and a mass electrobalance. Surfaces from the different experiments were examined using a scanning electron microscope to identify the presence of deposited species, and electron spectroscopy for chemical analysis to identify the species deposited on the surface. A better understanding of the equilibrium thermodynamics, the kinetics of the steam-accelerated volatilizations, and the release kinetics are gained by these experiments. The release rate is characterized by bulk vaporization/gas-phase mass transfer data. The analysis couples vaporization, deposition, and desorption of the compounds formed by cesium hydroxide and boric acid under conditions similar to what is expected during certain nuclear reactor accidents. This study shows that cesium deposits on an oxidized stainless steel surface at temperatures between 1000 and 1200 Kelvin. Cesium also deposits on stainless steel surfaces coated with boric oxide in the same temperature ranges. The mechanism for cesium deposition onto the oxide layer was found to involve the chemical reaction between cesium and chromate. Some revaporization in the cesium hydroxide-boric acid system was observed. It has been found that under the conditions given, boric acid will react with cesium hydroxide to form cesium metaborate. A model is proposed for this chemical reaction.

  16. Polarizabilities and Shielding Factors of Ions in Cesium Halide Crystals with the Cesium Chloride Structure

    Science.gov (United States)

    Mahbubar, Rahman; Michihiro, Yoshitaka; Nakamura, Koichi; Kanashiro, Tatsuo

    2001-08-01

    The calculated results of the polarizabilities and the quadrupole shielding factor of the ions in cesium halide crystals with the cesium chloride structure are presented. The calculation is done on the basis of the self-consistent field local density approximation and the modified Sternheimer equation. The crystalline potential is treated by the spherical solid model. The size effect is seen in the values of the polarizabilities and the quadrupole shielding factor. The values of the polarizabilities and the quadrupole shielding factor of cesium ion show only slight change in different crystals. The values of chlorine ion show significant reduction and the amount of the reduction is different in the different crystals. The effect of the crystalline environment on the electron states is discussed.

  17. Extraction of Cesium from the Irradiated Nuclear Waste by 4(5),4'(5')-Bis[1-hydroxyalkylbenzo]-21-crown-7

    Institute of Scientific and Technical Information of China (English)

    Ying DU; Wen Jun CHEN; Sheng Ying QIN

    2004-01-01

    4(5),4'(5')-Bis[l-hydroxyalkylbenzo]-21-crown-7 (A-C) have been synthesized by two-step reactions from dibenzo-21-crown-7 (DB21C7). Extraction of cesium cation from nitric acid solutions by A-C has been investigated in nitromethane. Under the conditions of various concentration of HNO3 or NaNO3, the extractabilities of A and B were superior to that of DB21C7.

  18. Digital Square-Wave Frequency Modulated Microwave Sources for a Miniature Optically Pumped Cesium Beam Clock

    Institute of Scientific and Technical Information of China (English)

    CHEN Jingbiao; ZHU Chengjin; LIU Ge; WANG Fengzhi; WANG Yiqiu; YANG Donghai

    2001-01-01

    Three different digital frequencymodulated microwave sources have been designed andapplied to our miniature optically pumped cesiumbeam clock.The main features and their influenceon clock accuracy have been experimentally tested.Itis proved that a digital square-wave frequency modu-lated microwave source using a microprocessor con-trolled direct-digital frequency synthesizer (DDFS)for our miniature optically pumped cesium beamclock works well,the frequency short term stability2 × 10 11/x r and the long term stability 3.5 x 10-13 forone day sample time have been obtained.

  19. Sugar-metal ion interactions: The coordination behavior of cesium ion with lactose, D-arabinose and L-arabinose

    Science.gov (United States)

    Jiang, Ye; Xue, Junhui; Wen, Xiaodong; Zhai, Yanjun; Yang, Limin; Xu, Yizhuang; Zhao, Guozhong; Kou, Kuan; Liu, Kexin; Chen, Jia'er; Wu, Jinguang

    2016-04-01

    The novel cesium chloride-lactose complex (CsCl·C12H22O10 (Cs-Lac), cesium chloride-D-arabinose and L-arabinose complexes (CsCl·C5H10O5, Cs-D-Ara and Cs-L-Ara) have been synthesized and characterized using X-ray diffraction, FTIR, FIR, THz and Raman spectroscopies. Cs+ is 9-coordinated to two chloride ions and seven hydroxyl groups from five lactose molecules in Cs-Lac. In the structures of CsCl-D-arabinose and CsCl-L-arabinose complexes, two kinds of Cs+ ions coexist in the structures. Cs1 is 10-coordinated with two chloride ions and eight hydroxyl groups from five arabinose molecule; Cs2 is 9-coordinated to three chloride ions and six hydroxyl groups from five arabinose molecules. Two coordination modes of arabinose coexist in the structures. α-D-arabinopyranose and α-L-arabinopyranose appear in the structures of Cs-D-Ara and Cs-L-Ara complexes. FTIR and Raman results indicate variations of hydrogen bonds and the conformation of the ligands after complexation. FIR and THz spectra also confirm the formation of Cs-complexes. Crystal structure, FTIR, FIR, THz and Raman spectra provide detailed information on the structure and coordination of hydroxyl groups to metal ions in the cesium chloride-lactose, cesium chloride-D- and L-arabinose complexes.

  20. Study of the removal of cesium from aqueous solutions by graphene oxide; Estudo da remocao de cesio em solucoes aquosas por oxido de grafeno

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, Vanessa N.; Rodrigues, Debora F. [University of Houston (UH), Houston, TX (United States); Vitta, Patricia B. Di [Universidade de Sao Paulo (STRES/USP), Sao Paulo, SP (Brazil). Inst. de Quimica. Setor Tecnico de Residuos Quimicos e Solventes; Oshiro, Mauricio T.; Vicente, Roberto; Hiromoto, Goro; Potiens Junior, Ademar; Sakata, Solange K., E-mail: sksakata@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Graphene oxide, used in this work, was synthesized from the oxidation of graphite by Hummer method. The experiments were performed in batch and analyzed for the following parameters: contact time, pH, cesium ion concentration in aqueous solution and removing capacity of the graphene oxide. After the experiments the samples were vacuum filtered and the remaining cesium in solution was quantified by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The equilibrium was reached after 60 minutes of contact in neutral solution. The percentage of removal was around 80%.

  1. Selective chemical binding enhances cesium tolerance in plants through inhibition of cesium uptake

    DEFF Research Database (Denmark)

    Adams, Eri; Chaban, Vitaly; Khandelia, Himanshu;

    2015-01-01

    High concentrations of cesium (Cs(+)) inhibit plant growth but the detailed mechanisms of Cs(+) uptake, transport and response in plants are not well known. In order to identify small molecules with a capacity to enhance plant tolerance to Cs(+), chemical library screening was performed using Ara...

  2. Cesium-associated hypokalemia successfully treated with amiloride.

    Science.gov (United States)

    Horn, Sarah; Naidus, Elliot; Alper, Seth L; Danziger, John

    2015-06-01

    Self-treatment of cancer with cesium chloride, despite proven lack of efficacy, continues to produce serious adverse effects. Among these is hypokalemia predisposing to life-threatening arrhythmia. The mechanism of cesium-associated hypokalemia (CAH) has not been described. We report urinary potassium wasting responsive to amiloride therapy in a cancer patient with CAH, and discuss possible mechanisms.

  3. Cesium-associated hypokalemia successfully treated with amiloride

    OpenAIRE

    Horn, Sarah; Naidus, Elliot; Alper, Seth L; Danziger, John

    2015-01-01

    Self-treatment of cancer with cesium chloride, despite proven lack of efficacy, continues to produce serious adverse effects. Among these is hypokalemia predisposing to life-threatening arrhythmia. The mechanism of cesium-associated hypokalemia (CAH) has not been described. We report urinary potassium wasting responsive to amiloride therapy in a cancer patient with CAH, and discuss possible mechanisms.

  4. Distillation device supplies cesium vapor at constant pressure

    Science.gov (United States)

    Basiulis, A.; Shefsiek, P. K.

    1968-01-01

    Distillation apparatus in the form of a U tube supplies small amounts of pure cesium vapor at constant pressure to a thermionic converter. The upstream leg of the U tube is connected to a vacuum pump to withdraw noncondensable impurities, the bottom portion serves as a reservoir for the liquid cesium.

  5. Colloid stable sorbents for cesium removal: preparation and application of latex particles functionalized with transition metals ferrocyanides.

    Science.gov (United States)

    Avramenko, Valentin; Bratskaya, Svetlana; Zheleznov, Veniamin; Sheveleva, Irina; Voitenko, Oleg; Sergienko, Valentin

    2011-02-28

    In this paper we suggest a principally new approach to preparation of colloid stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid stable sorbents toward cesium ions were studied in solutions containing up to 200 g/L of sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.3-1.5 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that made them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed.

  6. Colloid stable sorbents for cesium removal: Preparation and application of latex particles functionalized with transition metals ferrocyanides

    Energy Technology Data Exchange (ETDEWEB)

    Avramenko, Valentin [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Bratskaya, Svetlana, E-mail: sbratska@ich.dvo.ru [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Zheleznov, Veniamin; Sheveleva, Irina [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Voitenko, Oleg [Far Eastern Federal University, Laboratory of Electron Microscopy and Image Processing, 27, Oktyabr' skaya Street, Vladivostok 690950 (Russian Federation); Sergienko, Valentin [Institute of Chemistry, Far Eastern Branch, Russian Academy of Sciences, 159 ave 100-letiya Vladivostoka, Vladivostok 690022 (Russian Federation)

    2011-02-28

    In this paper we suggest a principally new approach to preparation of colloid stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) ferrocyanides in nanosized carboxylic latex emulsions. The effects of ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid stable sorbents toward cesium ions were studied in solutions containing up to 200 g/L of sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals ferrocyanides were in the range 1.3-1.5 mol Cs/mol ferrocyanide with the highest value found for the copper ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that made them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed.

  7. Adsorption of cesium on cement mortar from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Volchek, Konstantin, E-mail: konstantin.volchek@ec.gc.ca [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Miah, Muhammed Yusuf [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Department of Applied Chemistry and Chemical Technology, Noakhali Science and Technology University (Bangladesh); Kuang, Wenxing; DeMaleki, Zack [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, Canada K1A 0H3 (Canada); Tezel, F. Handan [Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis-Pasteur, Ottawa, Ontario, Canada K1N 6N5 (Canada)

    2011-10-30

    Highlights: {yields} The adsorption of cesium on cement mortar was investigated in a range of temperatures and cesium concentrations. {yields} The pseudo-second order kinetic model produced a good fit with the experimental kinetic data. {yields} Equilibrium test results correlated well with the Freundlich isotherm adsorption model. {yields} The interaction between cesium ions and cement mortar was dominated by chemical adsorption. - Abstract: The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L{sup -1} and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive {sup 137}Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L{sup -1} while the respective surface concentration on coupons varied from 0.0395 to 22.34 {mu}g cm{sup -2}. Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol{sup -1} suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar.

  8. [Surveillance of radioactive cesium in foods].

    Science.gov (United States)

    Nabeshi, Hiromi; Tsutsumi, Tomoaki; Ikarashi, Atsuko; Hachisuka, Akiko; Matsuda, Rieko

    2013-01-01

    We surveyed foods on the market from areas that had been exposed to radioactive materials contamination following the Fukushima accident. We used a NaI (Tl) scintillation spectrometer for the screening tests and a germanium semiconductor detector for the final tests. Test results from 1,427 samples showed that 6 samples (0.4%) exceeded the regulatory limit of 500 Bq/kg. Considering the detection rate of radioactive cesium in each food category, we suggest that it is necessary to continue monitoring fruits such as chestnuts and ginkgo nuts, mushrooms (especially raw wood-shiitake), mountain vegetables, and sea fish.

  9. Collagen-Immobilized Lipases Show Good Activity and Reusability for Butyl Butyrate Synthesis.

    Science.gov (United States)

    Dewei, Song; Min, Chen; Haiming, Cheng

    2016-11-01

    Candida rugosa lipases were immobilized onto collagen fibers through glutaraldehyde cross-linking method. The immobilization process has been optimized. Under the optimal immobilization conditions, the activity of the collagen-immobilized lipase reached 340 U/g. The activity was recovered of 28.3 % by immobilization. The operational stability of the obtained collagen-immobilized lipase for hydrolysis of olive oil emulsion was determined. The collagen-immobilized lipase showed good tolerance to temperature and pH variations in comparison to free lipase. The collagen-immobilized lipase was also applied as biocatalyst for synthesis of butyl butyrate from butyric acid and 1-butanol in n-hexane. The conversion yield was 94 % at the optimal conditions. Of its initial activity, 64 % was retained after 5 cycles for synthesizing butyl butyrate in n-hexane.

  10. Cesium removal from nuclear waste using a magnetical CuHCNPAN nano composite

    Science.gov (United States)

    Mobtaker, Hossein Ghasemi; Yousefi, Taher; Pakzad, Seyed Mohammadreza

    2016-12-01

    A nano-composite of copper hexacyanoferrate@polyacrylonitrile@magnetite (CuHCNPAN) was synthesized through chemical co-precipitation. The product were characterized using FT IR, XRD, SEM and TG techniques. The results of FTIR, XRD confirmed the composite formation. The SEM images showed that the particles are 20-60 nm in diameter. The composite showed high mechanical, chemical and thermal stability. The nano composite was used for removal of cesium ions from waste solutions. Effect of various parameters such as contact time, initial concentration, pH, competition ions and temperature were studied. After the metal ion adsorption process the magnetic separation of adsorbent from absorbents was carried out through external magnetic field. Maximum sorption capacity was about 260 mg/g. The kinetic studies showed that the equilibrium was achieved at 5 h and the experimental data fitted by the second order model. The adsorption isotherm was best modeled by Longmuir isotherm. The endothermic and spontaneous (and entropy increasing) nature of sorption process were approved by thermodynamic results. The results cleared which the synthesized CuHCNPAM composite is promising adsorbent for removal of cesium ions from nuclear waste.

  11. Adsorption of cesium on cement mortar from aqueous solutions.

    Science.gov (United States)

    Volchek, Konstantin; Miah, Muhammed Yusuf; Kuang, Wenxing; DeMaleki, Zack; Tezel, F Handan

    2011-10-30

    The adsorption of cesium on cement mortar from aqueous solutions was studied in series of bench-scale tests. The effects of cesium concentration, temperature and contact time on process kinetics and equilibrium were evaluated. Experiments were carried out in a range of initial cesium concentrations from 0.0103 to 10.88 mg L(-1) and temperatures from 278 to 313 K using coupons of cement mortar immersed in the solutions. Non-radioactive cesium chloride was used as a surrogate of the radioactive (137)Cs. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectroscopy. Depending on the initial cesium concentration, its equilibrium concentration in solution ranged from 0.0069 to 8.837 mg L(-1) while the respective surface concentration on coupons varied from 0.0395 to 22.34 μg cm(-2). Equilibrium test results correlated well with the Freundlich isotherm model for the entire test duration. Test results revealed that an increase in temperature resulted in an increase in adsorption rate and a decrease in equilibrium cesium surface concentration. Among several kinetic models considered, the pseudo-second order reaction model was found to be the best to describe the kinetic test results in the studied range of concentrations. The adsorption activation energy determined from Arrhenius equation was found to be approximately 55.9 kJ mol(-1) suggesting that chemisorption was the prevalent mechanism of interaction between cesium ions and cement mortar.

  12. Seaweed against strontium and preussian blue against cesium

    Directory of Open Access Journals (Sweden)

    G Michanek

    1988-06-01

    Full Text Available The fact that alginates bind strontium and cyanates bind cesium and are capable of removing these elements from living organisms is scientifically verified. Zeolites offer another possibility for exchange of these ions. Practical research should be initiated to find the right doses and procedure to decrease the body burden of radioactive isotopes in reindeer.Alger mot strontium och berlinerblått mot cesium.Abstract in Swedish / Sammanfattning: Mitt budskap år kort: Alger binder strontium, Berlinerblått binder cesium, Sätt fart på forskning och forsök!

  13. Evaluation of fungal laccase immobilized on natural nanostructured bacterial cellulose

    Directory of Open Access Journals (Sweden)

    Lin eChen

    2015-11-01

    Full Text Available The aim of this work was to assess the possibility of using native bacterial nanocellulose (BC as a carrier for laccase immobilization. BC was synthesized by Gluconacetobacter xylinus, which was statically cultivated in a mannitol-based medium and was freeze-dried to form BC sponge after purification. For the first time, fungal laccase from Trametes versicolor was immobilized on the native nanofibril network-structured BC sponge through physical adsorption and cross-linking with glutaraldehyde. The properties including morphologic and structural features of the BC as well as the immobilized enzyme were thoroughly investigated. It was found that enzyme immobilized by cross-linking exhibited broader pH operation range of high catalytic activity as well as higher running stability compared to free and adsorbed enzyme. Using ABTS as substrate, the optimum pH value was 3.5 for the adsorption-immobilized laccase and 4.0 for the crosslinking-immobilized laccase. The immobilized enzyme retained 69% of the original activity after being recycled 7 times. Novel applications of the BC-immobilized enzyme tentatively include active packaging, construction of biosensors, and establishment of bioreactors.

  14. Evaluation of Fungal Laccase Immobilized on Natural Nanostructured Bacterial Cellulose.

    Science.gov (United States)

    Chen, Lin; Zou, Min; Hong, Feng F

    2015-01-01

    The aim of this work was to assess the possibility of using native bacterial nanocellulose (BC) as a carrier for laccase immobilization. BC was synthesized by Gluconacetobacter xylinus, which was statically cultivated in a mannitol-based medium and was freeze-dried to form BC sponge after purification. For the first time, fungal laccase from Trametes versicolor was immobilized on the native nanofibril network-structured BC sponge through physical adsorption and cross-linking with glutaraldehyde. The properties including morphologic and structural features of the BC as well as the immobilized enzyme were thoroughly investigated. It was found that enzyme immobilized by cross-linking exhibited broader pH operation range of high catalytic activity as well as higher running stability compared to free and adsorbed enzyme. Using ABTS as substrate, the optimum pH value was 3.5 for the adsorption-immobilized laccase and 4.0 for the crosslinking-immobilized laccase. The immobilized enzyme retained 69% of the original activity after being recycled seven times. Novel applications of the BC-immobilized enzyme tentatively include active packaging, construction of biosensors, and establishment of bioreactors.

  15. Atmospheric transmission for cesium DPAL using TDLAS

    Science.gov (United States)

    Rice, Christopher A.; Perram, Glen P.

    2012-03-01

    The cesium (Cs) Diode Pumped Alkali Laser (DPAL) operates near 894 nm, in the vicinity of atmospheric water vapor absorption lines. An open-path Tunable Diode Laser Absorption (TDLAS) system composed of narrow band (~300 kHz) diode laser fiber coupled to a 12" Ritchey-Chrétien transmit telescope has been used to study the atmospheric transmission characteristics of Cs DPALs over extended paths. The ruggedized system has been field deployed and tested for propagation distances of greater than 1 km. By scanning the diode laser across many free spectral ranges, many rotational absorption features are observed. Absolute laser frequency is monitored with a High Finesse wavemeter to an accuracy of less than 10 MHz. Phase sensitive detection is employed with an absorbance of less than 1% observable under field conditions.

  16. Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch.

    Science.gov (United States)

    Uygun, Murat; Akduman, Begüm; Ergönül, Bülent; Aktaş Uygun, Deniz; Akgöl, Sinan; Denizli, Adil

    2015-01-01

    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 °C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 °C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and Km values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865 mg/mL, respectively. Vmax of immobilized amyloglucosidase was found to be (0.496 µmol/min) about four times less than that of free enzyme (2.020 µmol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54 mg/mL at the end of the 5 min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase.

  17. Low-work-function surfaces produced by cesium carbonate decomposition

    Science.gov (United States)

    Briere, T. R.; Sommer, A. H.

    1977-01-01

    Cesium carbonate (Cs2CO3) was heated to the decomposition temperature of approximately 600 C. The nonvolatile decomposition products were condensed on a nickel substrate while the carbon dioxide was removed by pumping. The deposited material is characterized by an effective work function of between 1.05 and 1.15 eV at 450 K and by photoemission in the visible and near-infrared region of the spectrum. It is suggested that the deposited material consists of Cs2O, possibly Cs2O2, and adsorbed cesium. Silver, evaporated from a heated silver bead, produced the typical photoemissive and thermionic properties of a silver-oxygen-cesium (S-1) photocathode. The material may be of interest for thermionic energy converters and for the formation of silver-oxygen-cesium photocathodes.

  18. Cesium and Strontium Specific Exchangers for Nuclear Waste Effluent Remediation

    Energy Technology Data Exchange (ETDEWEB)

    A. Clearfield; A. I. Bortun; L. A. Bortun; E. A. Bhlume; P. Sylvester; G. M. Graziano

    2000-09-01

    During the past 50 years, nuclear defense activities have produced large quantities of nuclear waste that now require safe and permanent disposal. The general procedure to be implemented involves the removal of cesium and strontium from the waste solutions for disposal in permanently vitrified media. This requires highly selective sorbents or ion exchangers. Further, at the high radiation doses present in the solution, organic exchangers or sequestrants are likely to decompose over time. Inorganic ion exchangers are resistant to radiation damage and can exhibit remarkably high selectivities. We have synthesized three families of tunnel-type ion exchangers. The crystal structures of these compounds as well as their protonated phases, coupled with ion exchange titrations, were determined and this information was used to develop an understanding of their ion exchange behavior. The ion exchange selectivities of these phases could be regulated by isomorphous replacement of the framework metals by larger or smaller radius metals. In the realm of layered compounds, we prepared alumina, silica, and zirconia pillared clays and sodium micas. The pillared clays yielded very high Kd values for Cs+ and were very effective in removing Cs+ from groundwaters. The sodium micas also had a high affinity for Cs+ but an even greater attraction for S42+. They also possess the property of trapping these ions permanently as the layers slowly decrease their interlayer distance as loading occurs. Sodium nonatitanate exhibited extremely high Kd values for Sr2+ in alkaline tank wastes and should be considered for removal of Sr2+ in such cases. For tank wastes containing complexing agents, we have found that adding Ca2+ to the solution releases the complexed Sr2+ which may then be removed with the CST exchanger.

  19. Covalent immobilization of lipases on monodisperse magnetic microspheres modified with PAMAM-dendrimer

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Weiwei [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China); Zhang, Yimei [Suzhou Research Academy of North China Electric Power University (China); Hou, Chen; Pan, Duo; He, Jianjun; Zhu, Hao, E-mail: zhuhao07@lzu.edu.cn [Lanzhou University, State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology (China)

    2016-02-15

    This paper reported an immobilization of Candida rugosa lipase (CRL) onto PAMAM-dendrimer-grafted magnetic nanoparticles synthesized by a modified solvothermal reduction method. The dendritic magnetic nanoparticles were amply characterized by several instrumental measurements, and the CRL was covalently anchored on the three generation supports with glutaraldehyde as coupling reagent. The amount of immobilized enzyme was up to 150 mg/g support and the factors related with the enzyme activity were investigated. The immobilization of lipase improved their performance in wider ranges of pH and temperature. The immobilized lipase exhibited excellent thermal stability and reusability in comparison with free enzyme and can be reused 10 cycles with the enzymatic activity remained above 90 %. The properties of lipase improved obviously after being immobilized on the dendritic supports. The inactive immobilized lipase could be regenerated with glutaraldehyde and Cu{sup 2+}, respectively. This synthetic strategy was facile and eco-friendly for applications in lipase immobilization.

  20. Optimization of Synthesis Condition for Nanoscale Zero Valent Iron Immobilization on Granular Activated Carbon

    DEFF Research Database (Denmark)

    Andersen, Henrik Rasmus; Hwang, Yuhoon; Mines, Paul D.;

    2016-01-01

    economical loss, but also potential risk to human health and environment. Thus, the immobilization onto coarse or structured support is essential. In this study, two representative processes for nZVI immobilization on granular activated carbon (GAC) were evaluated, and optimized conditions for synthesizing...

  1. SYNTHESIS AND CHARACTERIZATION OF SURFACE-HYPERBRANCHED MAGNETITE NANOPARTICLE FOR BOVINE SERUM ALBUMIN IMMOBILIZATION

    Institute of Scientific and Technical Information of China (English)

    Bifeng Pan; Feng Gao; Hongchen Gu

    2004-01-01

    A hyperbranched polyamidoamine polymer was synthesized on the surface of magnetite nanoparticles to enhance bovine serum albumin (BSA) immobilization efficiency. The amount of immobilized bovine serum albumin (BSA)on the surface-hyperbranched magnetite nanoparticle was up to 2.5 times as much as that of magnetite nanoparticle modified with only amino silane.

  2. THERMAL ACTIVATION OF IMMOBILIZED PAPAIN

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Papain (Papainase, EC 3.4.22.2) was immobilized on porous silica beads by cross linking with glutaraldehyde. The thermal activation of this immobilized papain in aqueous system was found at a temperature range from 50 to 90℃. The higher the temperature, the more active the immobilized papain will possess. At the same time,the durability of the immobilized papain on heating was greatly improved. The effect of additives and salts on the activity of the immobilized papain were also studied. The results showed that the additives and some of the salts studied could markedly enhance the activity of the immobilized papain at elevated temperature.

  3. Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

    Directory of Open Access Journals (Sweden)

    Ahmed S. Helal

    2016-05-01

    Full Text Available Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD, was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC. SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES. The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS, X-Ray Fluorescence spectrometry (XRF and Superconducting QUantum Interference Device (SQUID magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

  4. New Calix[4]arene dibenzocrown ethers for selective sensing of cesium ion in aqueous environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seung; Kim, Jong Kuk [Konyang University, Nonsan (Korea, Republic of); Choi, Wang Kyu; Lee, Kune Woo; Oh, Won Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    1,3-dialkoxycalix[4]arene dibenzocrown ethers (6-9) were successfully synthesized in the fixed 1,3-alternate conformation with over 90% yields by the reaction of corresponding 1,3dialkoxycalix[4]arenes 2-5 with dibenzodimesylate 13 in acetonitrile as a solvent in the presence of cesium carbonate as a base. In view of cyclization yield, the use of dimesylate is found to be better than that of dibenzoditosylate. With an unusual AB pattern in {sup 1}H NMR spectrum for compound 9, it is suggested that conformational structure of 1,3-diallyloxycalix[4]arene dibenzocrown ether be less flexible than that of usual 1,3-alternate calixcrown ether, probably due to steric effects of two ally1 group. Complexation of the corresponding calix[4]arene 6-9 toward alkali metal ions using single flux method through bulk liquid membrane system was found to give a high cesium selectivity. 28 refs., 1 tab., 1 fig.

  5. Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

    Science.gov (United States)

    Helal, Ahmed S.; Decorse, Philippe; Perruchot, Christian; Novak, Sophie; Lion, Claude; Ammar, Souad; El Hage Chahine, Jean-Michel; Hémadi, Miryana

    2016-05-01

    Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs) with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD), was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC). SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES). The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS), X-Ray Fluorescence spectrometry (XRF) and Superconducting QUantum Interference Device (SQUID) magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

  6. Cesium-induced QT-interval prolongation in an adolescent.

    Science.gov (United States)

    O'Brien, Catherine E; Harik, Nada; James, Laura P; Seib, Paul M; Stowe, Cindy D

    2008-08-01

    Alternative medicine is becoming increasingly popular, especially with terminally ill patients. Most alternative remedies have not been adequately studied or proven effective for the diseases for which they are promoted. In the worst cases, these therapies are harmful. We describe a 16-year-old girl with metastatic hepatocellular carcinoma who experienced cesium-induced QT-interval prolongation after the start of a cesium chloride-based alternative treatment regimen. She had received seven courses of chemotherapy, with a cumulative doxorubicin dose of 500 mg/m(2) over 5 months, resulting in minimal tumor regression. Against the advice of her oncologist, she abandoned traditional therapy and started an alternative regimen that included cesium chloride supplements. Two weeks later, the patient went to a local emergency department after experiencing two brief syncopal episodes. An electrocardiogram revealed occasional premature ventricular contractions, a QTc interval of 683 msec (normal range for females 450-460 msec), and R on T phenomenon. She was admitted to the hospital and later experienced monomorphic ventricular tachycardia, which resolved spontaneously. Lidocaine therapy was started, and the patient was transferred to a cardiac intensive care unit at our hospital. Her plasma cesium level was 2400 microg/dl (normal cesium level was 1800 microg/dl, and her QTc interval was 494 msec. According to the Naranjo adverse drug reaction probability scale, cesium was the probable cause of the patient's arrhythmia. In animal models, cesium chloride has induced cardiac arrhythmias, including torsade de pointes. It inhibits delayed rectifier potassium channels in the myocardium, causing delayed repolarization and QT-interval prolongation. Patients with cancer should be aware that alternative remedies may be harmful and ineffective. Because patients may be unlikely to self-report alternative remedies, health care providers should specifically ask their patients about any

  7. Cesium toxicity: a case of self-treatment by alternate therapy gone awry.

    Science.gov (United States)

    Lyon, Andrew W; Mayhew, William J

    2003-02-01

    Cesium salts have been used in animal models to induce cardiac arrhythmias for several decades, but the sequelae of human cesium toxicity have seldom been described. The authors describe a case of cesium toxicity manifested by syncope, polymorphic ventricular tachycardia, hypokalemia, and a QT interval prolonged to 650 milliseconds that resolved over 4 days following withdrawal of cesium. The patient had a 2-year history of colon cancer and had self-treated with cesium chloride, 3 g/d, for several weeks, using cesium as a form of alternate therapy for cancer. The authors describe the pathophysiologic correlates and risks of cesium consumption and conclude that cesium toxicity should be considered among the differential diagnoses of prolonged QT interval.

  8. A novel role for methyl cysteinate, a cysteine derivative, in cesium accumulation in Arabidopsis thaliana

    Science.gov (United States)

    Adams, Eri; Miyazaki, Takae; Hayaishi-Satoh, Aya; Han, Minwoo; Kusano, Miyako; Khandelia, Himanshu; Saito, Kazuki; Shin, Ryoung

    2017-01-01

    Phytoaccumulation is a technique to extract metals from soil utilising ability of plants. Cesium is a valuable metal while radioactive isotopes of cesium can be hazardous. In order to establish a more efficient phytoaccumulation system, small molecules which promote plants to accumulate cesium were investigated. Through chemical library screening, 14 chemicals were isolated as ‘cesium accumulators’ in Arabidopsis thaliana. Of those, methyl cysteinate, a derivative of cysteine, was found to function within the plant to accumulate externally supplemented cesium. Moreover, metabolite profiling demonstrated that cesium treatment increased cysteine levels in Arabidopsis. The cesium accumulation effect was not observed for other cysteine derivatives or amino acids on the cysteine metabolic pathway tested. Our results suggest that methyl cysteinate, potentially metabolised from cysteine, binds with cesium on the surface of the roots or inside plant cells and improve phytoaccumulation. PMID:28230101

  9. TWRS retrieval and storage mission, immobilized low-activity waste disposal plan

    Energy Technology Data Exchange (ETDEWEB)

    Shade, J.W.

    1998-01-07

    The TWRS mission is to store, treat, and immobilize highly radioactive Hanford waste (current and future tank waste and the encapsulated cesium and strontium) in a safe, environmentally sound, and cost-effective manner (TWRS JMN Justification for mission need). The mission includes retrieval, pretreatment, immobilization, interim storage and disposal, and tank closure. As part of this mission, DOE has established the TWRS Office to manage all Hanford Site tank waste activities. The TWRS program has identified the need to store, treat, immobilize, and dispose of the highly radioactive Hanford Site tank waste and encapsulated cesium and strontium materials in an environmentally sound, safe, and cost-effective manner. To support environmental remediation and restoration at the Hanford Site a two-phase approach to using private contractors to treat and immobilize the low-activity and high-level waste currently stored in underground tanks is planned. The request for proposals (RFP) for the first phase of waste treatment and immobilization was issued in February 1996 (Wagoner 1996) and initial contracts for two private contractor teams led by British Nuclear Fuels Ltd. and Lockheed-Martin Advanced Environmental Services were signed in September 1996. Phase 1 is a proof-of-concept and commercial demonstration effort to demonstrate the technical and business feasibility of using private facilities to treat Hanford Site waste, maintain radiological, nuclear, process, and occupational safety; and maintain environmental protection and compliance while reducing lifecycle costs and waste treatment times. Phase 1 production of ILAW is planned to begin in June 2002 and could treat up to about 13 percent of the waste. Phase 1 production is expected to be completed in 2007 for minimum order quantities or 2011 for maximum order quantities. Phase 2 is a full-scale production effort that will begin after Phase 1 and treat and immobilize most of the waste. Phase 2 production is

  10. Elucidating the structures and cooperative binding mechanism of cesium salts to the multitopic ion-pair receptor through density functional theory calculations.

    Science.gov (United States)

    Sadhu, Biswajit; Sundararajan, Mahesh; Velmurugan, Gunasekaran; Venuvanalingam, Ponnambalam

    2015-09-21

    Designing new and innovative receptors for the selective binding of radionuclides is central to nuclear waste management processes. Recently, a new multi-topic ion-pair receptor was reported which binds a variety of cesium salts. Due to the large size of the receptor, quantum chemical calculations on the full ion-pair receptors are restricted, thus the binding mechanisms are not well understood at the molecular level. We have assessed the binding strengths of various cesium salts to the recently synthesized multi-topic ion-pair receptor molecule using density functional theory based calculations. Our calculations predict that the binding of cesium salts to the receptor predominantly occurs via the cooperative binding mechanism. Cesium and the anion synergistically assist each other to bind favorably inside the receptor. Energy decomposition analysis on the ion-pair complexes shows that the Cs salts are bound to the receptor mainly through electrostatic interactions with small contribution from covalent interactions for large ionic radius anions. Further, QTAIM analysis characterizes the importance of different inter-molecular interactions between the ions and the receptor inside the ion-pair complexes. The role of the crystallographic solvent molecule contributes significantly by ~10 kcal mol(-1) to the overall binding affinities which is quite significant. Further, unlike the recent molecular mechanics (MM) calculations, our calculated binding affinity trends for various Cs ion-pair complexes (CsF, CsCl and CsNO3) are now in excellent agreement with the experimental binding affinity trends.

  11. Ion microscopy based on laser-cooled cesium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Viteau, M.; Reveillard, M.; Kime, L.; Rasser, B.; Sudraud, P. [Orsay Physics, TESCAN Orsay, 95 Avenue des Monts Auréliens – ZA Saint-Charles – 13710 Fuveau (France); Bruneau, Y.; Khalili, G.; Pillet, P.; Comparat, D. [Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Bât. 505, 91405 Orsay (France); Guerri, I. [Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Fioretti, A., E-mail: andrea.fioretti@ino.it [Istituto Nazionale di Ottica, INO-CNR, U.O.S. ”Adriano Gozzini”, via Moruzzi 1, 56124 Pisa (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, CNISM, Sezione di Pisa, 56127 Pisa (Italy); Ciampini, D.; Allegrini, M.; Fuso, F. [Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Istituto Nazionale di Ottica, INO-CNR, U.O.S. ”Adriano Gozzini”, via Moruzzi 1, 56124 Pisa (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, CNISM, Sezione di Pisa, 56127 Pisa (Italy)

    2016-05-15

    We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a laser-cooled cesium beam and adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130 pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1–5 keV range are obtained with a resolution around 40 nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of the eV, offering great prospects for lithography, imaging and surface analysis. - Highlights: • We realize a Focused Ion Beam with an ionic source based on laser cooled cesium atoms. • Ionization involves excitation of the laser cooled atoms to Rydberg states. • We use the cesium FIB system to image different materials. • We use the cesium FIB to produce permanent modifications on surfaces. • In the present configuration, the focused probe size of the cesium FIB prototype is about 300 nm for beam energies in the 2–5 keV range.

  12. DNA-directed immobilization of horseradish peroxidase onto porous SiO2 optical transducers

    Science.gov (United States)

    Shtenberg, Giorgi; Massad-Ivanir, Naama; Engin, Sinem; Sharon, Michal; Fruk, Ljiljana; Segal, Ester

    2012-08-01

    Multifunctional porous Si nanostructure is designed to optically monitor enzymatic activity of horseradish peroxidase. First, an oxidized PSi optical nanostructure, a Fabry-Pérot thin film, is synthesized and is used as the optical transducer element. Immobilization of the enzyme onto the nanostructure is performed through DNA-directed immobilization. Preliminary studies demonstrate high enzymatic activity levels of the immobilized horseradish peroxidase, while maintaining its specificity. The catalytic activity of the enzymes immobilized within the porous nanostructure is monitored in real time by reflective interferometric Fourier transform spectroscopy. We show that we can easily regenerate the surface for consecutive biosensing analysis by mild dehybridization conditions.

  13. Tuning the Optical Properties of Cesium Lead Halide Perovskite Nanocrystals by Anion Exchange Reactions.

    Science.gov (United States)

    Akkerman, Quinten A; D'Innocenzo, Valerio; Accornero, Sara; Scarpellini, Alice; Petrozza, Annamaria; Prato, Mirko; Manna, Liberato

    2015-08-19

    We demonstrate that, via controlled anion exchange reactions using a range of different halide precursors, we can finely tune the chemical composition and the optical properties of presynthesized colloidal cesium lead halide perovskite nanocrystals (NCs), from green emitting CsPbBr3 to bright emitters in any other region of the visible spectrum, and back, by displacement of Cl(-) or I(-) ions and reinsertion of Br(-) ions. This approach gives access to perovskite semiconductor NCs with both structural and optical qualities comparable to those of directly synthesized NCs. We also show that anion exchange is a dynamic process that takes place in solution between NCs. Therefore, by mixing solutions containing perovskite NCs emitting in different spectral ranges (due to different halide compositions) their mutual fast exchange dynamics leads to homogenization in their composition, resulting in NCs emitting in a narrow spectral region that is intermediate between those of the parent nanoparticles.

  14. Applications of cesium in the perovskite solar cells

    Science.gov (United States)

    Ye, Fengjun; Yang, Wenqiang; Luo, Deying; Zhu, Rui; Gong, Qihuang

    2017-01-01

    Perovskite solar cells have experienced an unprecedented rapid development in the power conversion efficiency (PCE) during the past 7 years, and the record PCE has been already comparable to the traditional polycrystalline silicon solar cells. Presently, it is more urgent to address the challenge on device stability for the future commercial application. Recently, the inorganic cesium lead halide perovskite has been intensively studied as one of the alternative candidates to improve device stability through controlling the phase transition. The cesium (Cs)-doped perovskites show more superior stability comparing with organic methylammonium (MA) lead halide perovskite or formamidinium (FA) lead halide perovskite. Here, recent progress of the inorganic cesium application in organic–inorganic perovskite solar cells (PSCs) is highlighted from the viewpoints of the device efficiency and the device stability. Project supported by the 973 Program of China (No. 2015CB932203), the National Natural Science Foundation of China (Nos. 61377025, 91433203), and the Young 1000 Talents Global Recruitment Program of China.

  15. Controllable evaporation of cesium from a dispenser oven

    Science.gov (United States)

    Fantz, U.; Friedl, R.; Fröschle, M.

    2012-12-01

    This instrument allows controlled evaporation of the alkali metal cesium over a wide range of evaporation rates. The oven has three unique features. The first is an alkali metal reservoir that uses a dispenser as a cesium source. The heating current of the dispenser controls the evaporation rate allowing generation of an adjustable and stable flow of pure cesium. The second is a blocking valve, which is fully metallic as is the body of the oven. This construction both reduces contamination of the dispenser and enables the oven to be operated up to 300 °C, with only small temperature variations (metal at a cold spot is significantly hindered. The last feature is an integral surface ionization detector for measuring and controlling the evaporation rate. The dispenser oven can be easily transferred to the other alkali-metals.

  16. Dating of mine waste in lacustrine sediments using cesium-137

    Science.gov (United States)

    Rember, W. C.; Erdman, T. W.; Hoffmann, M. L.; Chamberlain, V. E.; Sprenke, K. F.

    1993-11-01

    For over a century Medicine Lake in northern Idaho has received heavy-metal-laden tailings from the Coeur d'Alene mining district. Establishing the depositional chronology of the lake bottom sediments provides information on the source and rate of deposition of the tailings. Cesium-137, an isotope produced in the atmosphere by nuclear bomb tests, was virtually absent in the environment prior to 1951, but reached its apex in 1964. Our analysis of cesium-137 in the sediments of Medicine Lake revealed that 14 cm of fine-grained tailings were deposited in the lake from 1951 to 1964 and tailing deposition downstream was greatly reduced by the installation of tailings dams in the district in 1968. Cesium-137 analysis is accomplished by a fairly simple gamma-ray counting technique and should be a valuable tool for analyzing sedimentation in any lacustrine environment that was active during the 1950s and 1960s.

  17. Enzyme immobilization and biocatalysis of polysiloxanes

    Science.gov (United States)

    Poojari, Yadagiri

    Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

  18. Cesium in the Savannah River Site environment

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, W.H.; Bauer, L.R.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Pinder, J.E.; Strom, R.N.

    1992-03-01

    Cesium in the Savannah River Site Environment is published as a part of the Radiological Assessment Program (RAP). It is the fourth in a series of eight documents on individual radioisotopes released to the environment as a result of Savannah River Site (SRS) operations. The earlier documents describe the environmental consequences of tritium, iodine, and uranium. Documents on plutonium, strontium, carbon, and technetium will be published in the future. These are dynamic documents and current plans call for revising and updating each one on a two-year schedule.Radiocesium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite Cosmos 954, small releases from reactors and reprocessing plants, and the operation of industrial, medical, and educational facilities. Radiocesium has been produced at SRS during the operation of five production reactors. Several hundred curies of [sup 137]Cs was released into streams in the late 50s and 60s from leaking fuel elements. Smaller quantities were released from the fuel reprocessing operations. About 1400 Ci of [sup 137]Cs was released to seepage basins where it was tightly bound by clay in the soil. A much smaller quantity, about four Ci. was released to the atmosphere. Radiocesium concentration and mechanisms for atmospheric, surface water, and groundwater have been extensively studied by Savannah River Technology Center (SRTC) and ecological mechanisms have been studied by Savannah River Ecology Laboratory (SREL). The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by total doses of 033 mrem (atmospheric) and 60 mrem (liquid), compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Isotope [sup 137]Cs releases have resulted in a negligible risk to the environment and the population it supports.

  19. Cesium in the Savannah River Site environment

    Energy Technology Data Exchange (ETDEWEB)

    Carlton, W.H.; Bauer, L.R.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Pinder, J.E.; Strom, R.N.

    1992-03-01

    Cesium in the Savannah River Site Environment is published as a part of the Radiological Assessment Program (RAP). It is the fourth in a series of eight documents on individual radioisotopes released to the environment as a result of Savannah River Site (SRS) operations. The earlier documents describe the environmental consequences of tritium, iodine, and uranium. Documents on plutonium, strontium, carbon, and technetium will be published in the future. These are dynamic documents and current plans call for revising and updating each one on a two-year schedule.Radiocesium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite Cosmos 954, small releases from reactors and reprocessing plants, and the operation of industrial, medical, and educational facilities. Radiocesium has been produced at SRS during the operation of five production reactors. Several hundred curies of {sup 137}Cs was released into streams in the late 50s and 60s from leaking fuel elements. Smaller quantities were released from the fuel reprocessing operations. About 1400 Ci of {sup 137}Cs was released to seepage basins where it was tightly bound by clay in the soil. A much smaller quantity, about four Ci. was released to the atmosphere. Radiocesium concentration and mechanisms for atmospheric, surface water, and groundwater have been extensively studied by Savannah River Technology Center (SRTC) and ecological mechanisms have been studied by Savannah River Ecology Laboratory (SREL). The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by total doses of 033 mrem (atmospheric) and 60 mrem (liquid), compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Isotope {sup 137}Cs releases have resulted in a negligible risk to the environment and the population it supports.

  20. Selective chemical binding enhances cesium tolerance in plants through inhibition of cesium uptake

    Science.gov (United States)

    Adams, Eri; Chaban, Vitaly; Khandelia, Himanshu; Shin, Ryoung

    2015-03-01

    High concentrations of cesium (Cs+) inhibit plant growth but the detailed mechanisms of Cs+ uptake, transport and response in plants are not well known. In order to identify small molecules with a capacity to enhance plant tolerance to Cs+, chemical library screening was performed using Arabidopsis. Of 10,000 chemicals tested, five compounds were confirmed as Cs+ tolerance enhancers. Further investigation and quantum mechanical modelling revealed that one of these compounds reduced Cs+ concentrations in plants and that the imidazole moiety of this compound bound specifically to Cs+. Analysis of the analogous compounds indicated that the structure of the identified compound is important for the effect to be conferred. Taken together, Cs+ tolerance enhancer isolated here renders plants tolerant to Cs+ by inhibiting Cs+ entry into roots via specific binding to the ion thus, for instance, providing a basis for phytostabilisation of radiocesium-contaminated farmland.

  1. Immobilized Cell Research

    Science.gov (United States)

    1990-10-31

    beads, the plasmid is twice as stable as in cells In a process where immobilized cells produce material grown in continuous culture over 200...carrageenan) or chemically cross-linked, or- Penicillium chrysogenum than in washed freely suspended ganic polymer (Ca-alginate, polyacrylamide, and mycelium ...these materials are formed into the freely suspended cells stopped after 6 days. If the beads of several millimeters in diameter by allowing the

  2. Preparation of composites immobilizing highly selective adsorbents and their application to the separation of nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, Hitoshi [Tohoku Univ., Sendai (Japan); Onodera, Yoshio

    2001-03-01

    Radionuclides in high-level liquid waste are classified into four groups such as transuranic elements (TRU) group, technetium - platinum group, strontium - cesium group, and others group. Cesium showed high adsorption selectivity to AMP [(NH{sub 4}){sub 3}PO{sub 4}12MoO{sub 3}3H{sub 2}O], AWP [(NH{sub 4}){sub 3}PO{sub 4}12WO{sub 3}3H{sub 2}O], and KNiFC(K{sub 2-x}Ni{sub x/2}[NiFe(CN){sub 6}]nH{sub 2}O). These inorganic ion exchangers with selectivity of cesium are possible to be supported by porous materials and to be immobilized by polymer. Some examples (AMP/Al{sub 2}O{sub 3}, AMP/alginate, and KNiFC/zeolite) are shown in this paper. KCuFC/alginate can adsorb Pd into KCuFC, Ru into alginate, but can not adsorb Rh. Accordingly, platinum metals (Pd, Ru and Rh) are separated by it. Pd, Ru and Rh in their mixed solution are mutually separated by using Cyanex 302/alginate and chromatography. Eu and Am adsorbed by Cyanex 301-alginate acid gel microcapsule were separated by gradient elution. Then, 98.8% of Eu and 91.3% of Am were eluted at pH 2 and pH 1, respectively. (S.Y.)

  3. Spectroscopic investigations on glasses, glass-ceramics and ceramics developed for nuclear waste immobilization

    Science.gov (United States)

    Caurant, D.

    2014-05-01

    Highly radioactive nuclear waste must be immobilized in very durable matrices such as glasses, glass-ceramics and ceramics in order to avoid their dispersion in the biosphere during their radioactivity decay. In this paper, we present various examples of spectroscopic investigations (optical absorption, Raman, NMR, EPR) performed to study the local structure of different kinds of such matrices used or envisaged to immobilize different kinds of radioactive wastes. A particular attention has been paid on the incorporation and the structural role of rare earths—both as fission products and actinide surrogates—in silicate glasses and glass-ceramics. An example of structural study by EPR of a ceramic (hollandite) irradiated by electrons (to simulate the effect of the β-irradiation of radioactive cesium) is also presented.

  4. Sorption of cesium in young till soils

    Energy Technology Data Exchange (ETDEWEB)

    Lusa, Merja; Lempinen, Janne; Ahola, Hanna; Soederlund, Mervi; Lehto, Jukka [Helsinki Univ. (Finland). Laboratory of Radiochemistry; Lahdenperae, Anne-Maj [Saanio and Riekkola Oy, Consulting Engineers, Helsinki (Finland); Ikonen, Ari T.K. [Posiva Oy, Eurajoki (Finland)

    2014-10-01

    Soil samples from three forest soil pits were examined down to a depth of approximately three metres using 1 M ammonium acetate extraction and microwave-assisted extraction with concentrated nitric acid (HNO{sub 3}), to study the binding of cesium (Cs) at Olkiluoto Island, southern Finland. Ammonium acetate was used to extract the readily exchangeable Cs fractions roughly representing the Cs fraction in soil which is available for plants. Microwave-assisted HNO{sub 3} extraction dissolves various minerals, e.g. carbonates, most sulphides, arsenides, selenides, phosphates, molybdates, sulphates, iron (Fe) and manganese (Mn) oxides and some silicates (olivine, biotite, zeolite), and reflects the total Cs concentrations. Cs was mostly found in the strongly bound fraction obtained through HNO{sub 3} extraction. The average Cs concentrations found in this fraction were 3.53 ± 0.30 mg/kg (d.w.), 3.06 ± 1.86 mg/kg (d.w.) and 1.83 ± 0.42 mg/kg (d.w.) in the three soil pits, respectively. The average exchangeable Cs found in the ammonium acetate extraction in all three sampling pits was 0.015 ± 0.008 mg/kg (d.w.). In addition, Cs concentrations in the soil solution were determined and in situ distribution coefficients (K{sub d}) for Cs were calculated. Furthermore, the in situ K{sub d} data was compared with the Cs K{sub d} data obtained using the model batch experiments. The in situ K{sub d} values were observed to fairly well follow the trend of batch sorption data with respect to soil depth, but on average the batch distribution coefficients were almost an order of magnitude higher than the in situ K{sub d} data. In situ Cs sorption data could be satisfactory fitted with the Langmuir sorption isotherm, but the Freundlich isotherm failed to fit the data. Finally, distribution coefficients were calculated by an ion exchange approach using soil solution data, the cation exchange capacity (CEC) as well as Cs to sodium (Na) and Cs to potassium (K) ion exchange selectivity

  5. Surface Electrical Conductivity of Single Crystal Spinel in Cesium Vapour.

    Science.gov (United States)

    2007-11-02

    magnesium aluminate spinel at temperatures ranging from 573K to 923K, in the presence of cesium vapour at pressures up to 1Torr. The interest in spinel has...in the core of a nuclear reactor. In contrast to magnesium oxide and alumina, electron irradiation of spinel produces no dislocation structures

  6. Detection of quadrupole relaxation in an optically pumped cesium vapour

    Energy Technology Data Exchange (ETDEWEB)

    Bernabeu, E.; Tornos, J.

    1985-10-01

    The relaxation of quadrupole orientation induced by means of optical pumping in a cesium vapour is experimentally studied, and the results are compared to the theoretical predictions. The optical detection process of this type of orientation is also discussed as a function of the polarization and spectral profile of the detection light.

  7. Fundamental study of cesium decontamination from soil by superconducting magnet

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Susumu, E-mail: igarashi@qb.see.eng.osaka-u.ac.jp; Mishima, Fumihito; Akiyama, Yoko, E-mail: yoko-ak@see.eng.osaka-u.ac.jp; Nishijima, Shigehiro

    2013-11-15

    Highlights: •The method for the soil decontamination by the superconducting magnet is proposed. •Cesium ion can be absorbed by Prussian blue in potassium iodide wash fluid. •It is possible to recover Cs{sup +} ion-adsorbing Prussian blue with a high rate by HGMS. •It is expected that HGMS can be applied to the actual soil decontamination. -- Abstract: The radioactive substances have been spread out all over the surrounding area of Fukushima Daiichi Nuclear Power Plant caused by the accident in March 2011. Decontamination and volume reduction of radioactive substances, especially cesium ion, are desired issue. This study proposed a decontamination method of the soil by the magnetic separation using superconducting magnet. Cesium ion was adsorbed by Prussian blue in the potassium iodide solution. We succeeded in separating selectively the cesium ion-adsorbed Prussian blue out of the liquid phase by high gradient magnetic separation. High recovery ratio of the Prussian blue was achieved by this method.

  8. Membrane-based separation technologies for cesium, strontium, and technetium

    Energy Technology Data Exchange (ETDEWEB)

    Kafka, T.

    1996-10-01

    This work is one of two parallel projects that are part of an ESP task to develop high-capacity, selective, solid extractants for cesium, strontium, and technetium from nuclear wastes. In this subtask, Pacific Northwest National Laboratory (PNNL) is collaborating with 3M, St. Paul, Minnesota, working in cooperation with IBC Advanced Technologies, American Fork, Utah.

  9. Suspension of superfluid helium using cesium-coated surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M.C.; Giese, C.F.; Halley, J.W. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    1996-03-01

    We report results of an experiment which demonstrates that a layer of superfluid helium can be suspended over a cesium-coated orifice. By measuring the layer thickness with a capacitance bridge, we have shown in two runs that fluid layers up to 2 mm thick were suspended over a 70-{mu}m-diam cesium-coated orifice in a platinum foil for over 2 h in a cryostat held at 1.2 K. The effect depends on the recently established fact that superfluid helium does not wet cesium-coated surfaces. As a consequence, superfluid helium is expected to form a stable meniscus across such a cesium-coated hole. The observed depths of suspended helium are consistent with a simple theoretical model based on this picture. We briefly discuss the possible application of this method to the performance of a proposed experiment to study quantum coherence in superfluid helium by directing pulsed beams of helium atoms at such a suspended layer of fluid. {copyright} {ital 1996 The American Physical Society.}

  10. Preparation of cesium targets for gamma-spectroscopic studies

    Science.gov (United States)

    Bhattacharyya, S.; Basu, S. K.; Chanda, S.; Deb, P.; Eqbal, Md; Kundu, S.; Joseph, D.

    2000-11-01

    A procedure to prepare monoisotopic cesium compound targets for gamma-spectroscopic experiments is described. Using this procedure, uniform targets up to thicknesses of 0.6-1.2 mg/cm 2 were prepared and used for in-beam spectroscopic studies. The purity of the target was tested by energy dispersive X-ray fluorescence (EDXRF) measurements.

  11. Cesium-137 Levels Detected in Otters from Austria

    Directory of Open Access Journals (Sweden)

    Gutleb A.C.

    1991-02-01

    Full Text Available Pollution seems to be one of the most important causes for the decline of the European otter (Lutra lutra. The accident in the Chernobyl nuclear power plant added another aspect to environmental pollution. Few data on cesium-137 contents in otters are available, so levels were measured in 3 otters from Austria. All levels found were very low.

  12. Stable solidification of cesium with an allophane additive by a pressing/sintering method

    Science.gov (United States)

    Zhang, Xiaoxia; Wu, Yan; Wei, Yuezhou; Mimura, Hitoshi; Matsukura, Minoru

    2017-03-01

    Pyrolysis of AMP/SiO2 adsorbed Cs (AMP-Cs/SiO2) occurred at > 400 °C sintering temperature, and Cs immobilisation decreased from 100% to 40% after sintering at 1200 °C. To safely dispose radioactive Cs, allophane was immobilized with AMP-Cs/SiO2 to prepare a stable form by using a pressing/sintering method. The structure of AMP-Cs/SiO2 collapsed, and cesium aluminosilicate formed more easily under conditions of higher sintering temperature (>800 °C) or increasing mixing ratio of allophane (mass ratio = 1:3 AMP-Cs/SiO2-allophane). The decomposition products of AMP-Cs/SiO2 were Cs2O, MoO3 and P2O5 at 1200 °C. Cs2O volatilisation was depressed by allophane addition, and a stable immobilisation phase of Cs4Al4Si20O48 formed. An immobilisation ratio of Cs of approximately 100% was maintained. The leachability of Cs for AMP-Cs/SiO2-allophane (1:3, 1200 °C) in distilled water at 25 °C and 90 °C for 15 days was estimated as 0.174% and 1.55%, respectively.

  13. Irreversible Wash Aid Additive for Cesium Mitigation. Small-Scale Demonstration and Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-01-01

    The Irreversible Wash Aid Additive process has been under development by the U.S. Environmental Protection Agency (EPA) and Argonne National Laboratory (Argonne). This process for radioactive cesium mitigation consists of a solution to wash down contaminated structures, roadways, and vehicles and a sequestering agent to bind the radionuclides from the wash water and render them environmentally immobile. The purpose of this process is to restore functionality to basic services and immediately reduce the consequences of a radiologically-contaminated urban environment. Research and development have resulted in a down-selection of technologies for integration and demonstration at the pilot-scale level as part of the Wide Area Recovery and Resiliency Program (WARRP) under the Department of Homeland Security and the Denver Urban Area Security Initiative. As part of developing the methods for performing a pilot-scale demonstration at the WARRP conference in Denver in 2012, Argonne conducted small-scale field experiments at Separmatic Systems. The main purpose of these experiments was to refine the wash water collection and separations systems and demonstrate key unit operations to help in planning for the large scale demonstration in Denver. Since the purpose of these tests was to demonstrate the operations of the system, we used no radioactive materials. After a brief set of experiments with the LAKOS unit to familiarize ourselves with its operation, two experiments were completed on two separate dates with the Separmatic systems.

  14. Catalytic properties of maltogenic α-amylase from Bacillus stearothermophilus immobilized onto poly(urethane urea) microparticles.

    Science.gov (United States)

    Straksys, Antanas; Kochane, Tatjana; Budriene, Saulute

    2016-11-15

    The immobilization of maltogenic α-amylase from Bacillus stearothermophilus (BsMa) onto novel porous poly(urethane urea) (PUU) microparticles synthesized from poly(vinyl alcohol) and isophorone diisocyanate was performed by covalent attachment to free isocyanate groups from PUU microparticles, or by physical adsorption of enzyme onto the surface of the carrier. The influence of structure, surface area and porosity of microparticles on the catalytic properties of immobilized BsMa was evaluated. The highest efficiency of immobilization of BsMa was found to be 72%. Optimal activity of immobilized BsMa was found to have increased by 10°C compared with the native enzyme. Influence of concentration of sodium chloride on activity of immobilized BsMa was evaluated. High storage and thermal stability and reusability for starch hydrolysis of immobilized enzyme were obtained. Immobilized BsMa has a great potential for biotechnology.

  15. Selective extraction of cesium: from compound to process; Extraction selective du cesium: de la molecule au procede

    Energy Technology Data Exchange (ETDEWEB)

    Simon, N.; Eymard, S.; Tournois, B.; Dozol, J.F. [CEA Cadarache, Dept. d' Entreposage et de Stockage des Dechets (DCC/DESD/SEP), 13 - Saint-Paul-lez-Durance (France)

    2000-07-01

    Under the French law of 30 December 1991 on nuclear waste management, research is conducted to recover long-lived fission products from high-level radioactive effluents generated by spent fuel reprocessing, in order to destroy them by transmutation or encapsulate them in specific matrices. Cesium extraction with mono and bis-crown calix(4)arenes (Frame 1) is a candidate for process development. These extractants remove cesium from highly acidic or basic pH media even with high salinity. A real raffinate was treated in 1994 in a hot cell to extract cesium with a calix-crown extractant. The success of this one batch experiment confirmed the feasibility of cesium decontamination from high-level liquid waste. It was then decided to develop a process flowchart to extract cesium selectively from high-level raffinate, to be included in the general scheme of long-lived radionuclide partitioning. It was accordingly decided to develop a process based on liquid-liquid extraction and hence optimize a calixarene/diluent solvent according to: - hydraulic properties: density, viscosity, interfacial tension, - chemical criteria: sufficient cesium extraction (depending on the diluent), kinetics, third phase elimination... New mono-crown-calixarenes branched with long aliphatic groups (Frame 2) were designed to be soluble in aliphatic diluents. To prevent third phase formation associated with nitric acid extraction, the addition of modifiers (alcohol, phosphate and amide) in the organic phase was tested (Frame 3). Table 1 shows examples of calixarene/diluent systems suitable for a process flowchart, and Figure 2 provides data on cesium extraction with these new systems. Alongside these improvements, a system based on a modified 1,3-di(n-octyl-oxy)2,4-calix[4]arene crown and a modified diluent was also developed, considering a mixed TPH/NPHE system as the diluent, where TPH (hydrogenated tetra propylene) is a common aliphatic industrial solvent and NPHE is nitrophenyl

  16. IMMOBILIZATION OF PAPAIN ON CHITOSAN

    OpenAIRE

    Cahyaningrum, Sari Edi; Narsito, Narsito; Santoso, Sri Juari; Agustini, Rudiana

    2010-01-01

    In this study, papain was immobilized on chitosan with Mg(II) cosslinked agent. Studies on free and immobilized papain systems for determination of optimum pH, optimum temperatur, thermal stability and reusability were carried out. The results showed that free papain had optimum pH 6.5 and optimum temperature 55 °C while the immobile papain hadoptimum pH 8 and optimum temperature 80 °C. The thermal stability of the immobilized papain, relative to that of the free papain, was markedly increase...

  17. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

    Science.gov (United States)

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A; El-Toni, Ahmed M; Almaary, Khalid S; El-Tayeb, Mohamed A; Elbadawi, Yahya B; Antranikian, Garabed

    2016-01-29

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS-NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V(max), k(cat) and k(cat)/K(m), than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media.

  18. 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.

  19. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    Science.gov (United States)

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen

    2007-05-08

    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals.

  20. Silica-Immobilized Enzyme Reactors

    Science.gov (United States)

    2007-08-01

    immobilized artificial membrane chromatography and lysophospholipid micellar electrokinetic chromatography . J. Chromatogr. A 1998, 810, 95-103. 50...Journal of Liquid Chromatography and Related Technologies. Air Force Research Laboratory Materials and Manufacturing Directorate Airbase...immobilized enzyme reactors (IMERs) can also be integrated directly to further analytical methods such as liquid chromatography or mass spectrometry.[6] In

  1. Preparation, characterization, and luminescence of (SBA-15) immobilized pepsin

    Science.gov (United States)

    Zhai, Qing-Zhou; Sun, Si-Jia

    2014-12-01

    SBA-15 mesoporous silica was synthesized by hydrothermal method and its surface was methylated by treatment with methyltrimethoxysilane. Pepsin was immobilized on the obtained materials giving host-guest composite materials (SBA-15)-pepsin and (methylated SBA-15)-pepsin. The optimum conditions for preparation of these materials were established. Methylated SBA-15 (M-SBA-15) has improved immobilization efficiency of enzyme compared to initial SBA-15 silica. It was shown that with the gradual increase of NaCl solution ionic strength the immobilized amount of enzyme was reduced. Powder X-ray diffraction and Fourier transform infrared spectroscopy showed that the host frameworks in the prepared host-guest composite materials are intact and the ordered structure was retained. Scanning electron microscopic studies revealed fibrous morphologic characteristics of the SBA-15 and the immobilized pepsin composite materials. The average particle diameter of (SBA-15)-pepsin composite was 338 ± 10 and 343 ± 10 nm for (M-SBA-15)-pepsin. The low temperature N2 adsorption-desorption study at 77 K showed that the pore sizes and specific surface areas of the host-guest composite materials were smaller than those before the introduction of the enzyme, suggesting that the immobilized enzyme occupied a definite position in the host material pore channels. The UV-vis solid diffuse reflectance and luminescence studies showed that the enzyme was successfully immobilized on to the host material and that after the immobilization of enzyme on SBA-15 the conformation of pepsin macromolecule has not been changed.

  2. [Immobilization of heavy metal Pb2+ with geopolymer].

    Science.gov (United States)

    Jin, Man-tong; Jin, Zan-fang; Huang, Cai-ju

    2011-05-01

    A series of geopolymers were synthesized by mixing metakaolinite, water glass, sodium hydroxide and water, and the lead ion solidification experiments were performed with the geopolymer. Then, the immobilization efficiency was characterized by monitoring the leaching concentration and compressive strength of solidified products. Additionally, the structure and properties of the solidified products were studied by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of immobilization efficiency, microstructure and mineral structure, the difference between geopolymer and cement on the performance of immobilizing heavy metals was discussed. The results of lead ion immobilization experiments showed that over 99.7% of heavy metal was captured by the geopolymer as the doping concentration of lead ion was less than 3%. Meanwhile, the compressive strength of the solidified product ranged from 40 MPa to 50 MPa. Furthermore, by using the same Pb2+ concentration, the geopolymer showed higher compressive strength and lower leaching concentration compared to the cement. Because lead ion participated in constitution of structure of geopolymer, or Pb2+ was adsorbed by the aluminium ions on the geopolymeric skeleton and held in geopolymer. However, cement mainly solidified lead ion by physical encapsulation and adsorption mechanism. Therefore, both from the compressive strength and leaching concentration and from the microstructure characterization as well as the mechanism of the geopolymerization reaction, the geopolymer has more advantages in immobilizing Pb2+ than the cement.

  3. A facile and effective immobilization of glucose oxidase on tannic acid modified CoFe2O4 magnetic nanoparticles.

    Science.gov (United States)

    Altun, Seher; Çakıroğlu, Bekir; Özacar, Münteha; Özacar, Mahmut

    2015-12-01

    This article presents a study of glucose oxidase (GOx) immobilization by employing tannic acid (TA) modified-CoFe2O4 (CFO) magnetic nanoparticles which demonstrates novel aspect for enzyme immobilization. By using the strong protein and tannic acid binding, GOx immobilization was carried out via physical adsorption in a simpler way compared with the other immobilization methods which require various chemicals and complicated procedures which is difficult, expensive, time-consuming, and destructive to the enzyme structure. CFO was synthesized by hydrothermal synthesis and modified with TA to immobilize GOx. The immobilized GOx demonstrated maximum catalytic activity at pH 6.5 and 45 °C. The samples were characterized by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, and fourier transform infrared spectroscopy (FTIR), all of which confirm the surface modification of CFO and GOx immobilization. Also, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were performed to demonstrate the surface morphology and chemical structure of samples. According to the Lineweaver-Burk plot, GOx possessed lower affinity to glucose after immobilization, and the Michelis-Menten constant (KM) of immobilized and free GOx were found to be 50.05 mM and 28.00 mM, respectively. The immobilized GOx showed excellent reusability, and even after 8 consecutive activity assay runs, the immobilized GOx maintained ca. 60% of its initial activity.

  4. Covalent immobilization of triacylglycerol lipase onto functionalized novel mesoporous silica supports.

    Science.gov (United States)

    Bai, Yong-Xiao; Li, Yan-Feng; Yang, Yong; Yi, Liu-Xiang

    2006-10-01

    A novel mesoporous silica material was synthesized via a silicate salt route in the presence of polyvinyl alcohol as the structure-directing agent under acidic conditions. The material was functionalized and employed as the supports (LPS-1 and LPS-2) for immobilizing triacylglycerol lipase from porcine pancreas (PPL). Not only they had a good thermal stability and reusability but also the activity recovery of LPS-1 and LPS-2 reached to 69% and 76%, respectively. The optimal pH and temperature region of the LPS supports immobilized PPL for hydrolysis of olive oil were at 8.0 and 55-60 degrees C. Kinetic parameters such as maximum velocity (V(max)) and the Michaelis constant (K(m)) were determined for the free and the immobilized lipase and LPS-2 immobilized PPL had the highest catalytic efficiency in the three. Meanwhile, the LPS supports exhibited many advantages than small porous materials for immobilizing PPL.

  5. Polystyrene Attached Pt(IV)–Azomethine, Synthesis and Immobilization of Glucose Oxidase Enzyme

    Science.gov (United States)

    Sarı, Nurşen; Antepli, Esin; Nartop, Dilek; Yetim, Nurdan Kurnaz

    2012-01-01

    Modified polystyrene with Pt(IV)–azomethine (APS–Sch–Pt) was synthesized by means of condensation and demonstrated to be a promising enzyme support by studying the enzymatic properties of glucose oxidase enzyme (GOx) immobilized on it. The characteristics of the immobilized glucose oxidase (APS–Sch–Pt–GOx) enzyme showed two optimum pH values that were pH = 4.0 and pH = 7. The insertion of stable Pt(IV)–azomethine spacers between the polystyrene backbone and the immobilized GOx, (APS–Sch–Pt–GOx), increases the enzymes’ activity and improves their affinity towards the substrate even at pH = 4. The influence of temperature, reusability and storage capacity on the free and immobilized glucose oxidase enzyme was investigated. The storage stability of the immobilized glucose oxidase was shown to be eleven months in dry conditions at +4 °C. PMID:23109888

  6. Kelvin Probe Studies of Cesium Telluride Photocathode for AWA Photoinjector

    CERN Document Server

    Wisniewski, Eric; Yusof, Zikri; Spentzouris, Linda; Terry, Jeff; Harkay, Katherine

    2012-01-01

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (~50 nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  7. Nutrients and cancer: an introduction to cesium therapy.

    Science.gov (United States)

    Sartori, H E

    1984-01-01

    A brief overview on the relevance in dietary factors in both development and prevention of cancer is presented. The pharmacologic properties of various food ingredients are discussed. Establishing of a special diet for the cancer patient is suggested. In addition, avoidance of certain foods is recommended to counteract mucus production of cancer cells. Evaluation of the nutrient content of certain diets in regions with low incidence of cancer has advanced the use of certain alkali metals, i.e., rubidium and cesium, as chemotherapeutic agents. The rationale for this approach termed the "high pH" therapy resides in changing the acidic pH range of the cancer cell by cesium towards weak alkalinity in which the survival of the cancer cell is endangered, and the formation of acidic and toxic materials, normally formed in cancer cells, is neutralized and eliminated.

  8. Cesium-137, a drama recounted; Cesio-137, um drama recontado

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Suzane de Alencar

    2013-01-15

    The radiological accident with Cesium-137, which started on Goiania in 1987, did not stop with the end of radiological contamination and continues in a judicial, scientific and narrative process of identification and recognition of new victims. The drama occupies a central place on the dynamics of radiological event, as it extends its limits, inflects its intensity and updates the event. As a narrative of the event, the ethnography incorporates and brings up to date the drama as an analysis landmark and the description of the theme as it is absorbed by a dramatic process. Cesium-137, a drama recounted is a textual experimentation based on real events and characters picked out from statements reported in various narratives about the radiological accident. (author)

  9. Fiber laser system for cesium and rubidium atom interferometry

    CERN Document Server

    Diboune, Clément; Bidel, Yannick; Cadoret, Malo; Bresson, Alexandre

    2016-01-01

    We present an innovative fiber laser system for both cesium and rubidium manipulation. The architecture is based on frequency conversion of two lasers at 1560 nm and 1878 nm. By taking advantage of existing fiber components at these wavelengths, we demonstrate an all fiber laser system delivering 350 mW at 780 nm for rubidium and 210 mW at 852 nm for cesium. This result highlights the promising nature of such laser system especially for Cs manipulation for which no fiber laser system has been reported. It offers new perspectives for the development of atomic instruments dedicated to onboard applications and opens the way to a new generation of atom interferometers involving three atomic species $^{85}$Rb, $^{87}$Rb and $^{133}$Cs for which we propose an original laser architecture.

  10. New thermodynamic regularity for cesium over the whole liquid range

    CERN Document Server

    Ghatee, M H

    2001-01-01

    In this paper we derive an equation of state for liquid cesium based on a suggested potential function in accord to the characteristics large attraction and soft repulsion at the asymptotes of interaction potentials. By considering the interaction of nearest adjacent atoms in dense fluid, the equation of state predicts that the isotherm is linear function of, where is the compression factor, is the molar volume, and is the molar density. The linear parameters are identified as interaction coefficients related to attraction and repulsion, and are used to evaluate the molecular parameters with interesting implications. The isotherm is intended to resolve the particular thermodynamic properties of alkali metals, which have been known for their unusual change of the nature of intermolecular force as the characteristic metal-nonmetal transition range is approached. When applied to liquid cesium, the isotherms persist linear over the whole liquid range including the metal non-metals transition range and at the crit...

  11. Spectrally selective optical pumping in Doppler-broadened cesium atoms

    Science.gov (United States)

    Zhang, Jun-Hai; Zeng, Xian-Jin; Li, Qing-Meng; Huang, Qiang; Sun, Wei-Min

    2013-05-01

    The D1 line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations. The process, described by a three-level model with the Λ scheme, shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms. The |Fg = 3> → |Fe = 4> resonance pumping can result in the ground state |Fg = 4, mF = 4> sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state Fg = 4. To enhance the anisotropy in the ground state, we suggest employing dichromatic optical HF pumping by adding a laser to excite D1 line |Fg = 4> → |Fe = 3> transition, in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth's average magnetic field.

  12. Test procedures and instructions for Hanford tank waste supernatant cesium removal

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W., Westinghouse Hanford

    1996-05-31

    This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test using Hanford Double-Shell Slurry Feed supernatant liquor from tank 251-AW-101 in a bench-scale column.Cesium sorbents to be tested include resorcinol-formaldehyde resin and crystalline silicotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-022, Hanford Tank Waste Supernatant Cesium Removal Test Plan.

  13. Test procedures and instructions for Hanford complexant concentrate supernatant cesium removal using CST

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W.

    1997-01-08

    This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test, using Hanford Complexant Concentrate supernatant liquor from tank 241-AN-107, in a bench-scale column. The cesium sorbent to be tested is crystalline silicotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-023, Hanford Complexant Concentrate Supernatant Cesium Removal Test Plan.

  14. Study About Origin of Radioactive Cesium in Wild Mushroom in Japan

    OpenAIRE

    鎌田, 素之; 角田, 光淳

    2016-01-01

    Radioactive cesium, released from the Fukushima I nuclear power plant that destroyed by Great East Japan Earthquake, has been detected from various agricultural products. Especially, wild mushrooms are known to assimilate radioactive cesium and other heavy metals. In this study, we focused on the concentration of radioactive cesium in wild mushrooms in Japan, calculated the ratio of 134Cs/137Cs and discussed on their origin whether they were released from the Fukushima I nuclear power plant o...

  15. IMMOBILIZATION OF LIPASE FROM PORCINE PANCREAS ON POLY (METHYL ACRYLATE)COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    XuHuixian; LiMinqin; 等

    1994-01-01

    A series of poly(methyl acrylate) copolymers of different pore structures were synthesized and functionalized by polyethylene polyamine.The lipase from porcine pancreas was adsorbed on these polymer carriers. It was found that the proe structure and functional group were basic factors which affected the activity of immobilized lipase,The optimal conditions for adsorbing lipase were studied and the effects of pH,ionic strength and temperature on the immobilized lipase were compared with those on the dissolved lipase.

  16. Fatal Cesium Chloride Toxicity After Alternative Cancer Treatment

    OpenAIRE

    Sessions, Daniel; Heard, Kennon; Kosnett, Michael

    2013-01-01

    Background: Cesium chloride (CsCl) is sold as a treatment for several types of cancers. The purported mechanism of action is alkalinization of relatively acidic neoplastic cells. The efficacy of CsCl has not been demonstrated in controlled experiments. Oral and intravenous CsCl use has been associated with seizures, cardiotoxicity, syncope, and death. Although intratumoral treatment with various antineoplastic agents is described, no cases of intratumoral cancer treatment with CsCl have been ...

  17. Cesium pentazolate: A new nitrogen-rich energetic material

    Science.gov (United States)

    Steele, Brad A.; Stavrous, Elissaios; Prakapenka, Vitali B.; Radousky, Harry; Zaug, Joseph; Crowhurst, Jonathan C.; Oleynik, Ivan I.

    2017-01-01

    We report theoretical and experimental evidence for a new class of high-nitrogen content energetic material compounds consisting of molecular pentazoles, which are stabilized in the crystal phase upon introduction of elemental cesium. First-principles structural predictions show that the material with composition CsN5 is thermodynamically stable above 15 GPa. Indexing of the measured X-ray diffraction spectra indicate the synthesis of this material at 60 GPa as well its stability upon decompression down to 24 GPa.

  18. MECHANISM OF CESIUM EXCHANGE WITH POTASSIUM TITANIUM HEXACYANOFERRATE

    Institute of Scientific and Technical Information of China (English)

    XuShiping; SunYongxia; 等

    1998-01-01

    The mechanism of cesium exchange on potassium titanium hexacyanoferrate (KTiFC) is described in this paper.The dependence of the exchange rate on temperature,particle granule size,and shaking frequency is studied.The results show that ion exchange process is controlled by liquid film diffusion in granule particle.An exchange reaction occurs mainly between K+ in the exchanger and Cs+ in the solution.

  19. Studies on the Separation of Cesium From Fission Products

    Institute of Scientific and Technical Information of China (English)

    QIANLi-juan; ZHANGSheng-dong; GUOJing-ru; CUIAn-zhi; YANGLei; WUWang-suo

    2003-01-01

    135Cs is a long-life fission product. When measuring its thermal cross section, we must separate radiochemical purity cesium from fission products. Except for decontaminating radio- nuclides, others which can be activated must be avoided to come into solution. So ion exchanger is used. Inorganic ion exchangers have received increased attention because of their high resistance to radiation and their very efficient separation of alkali metal ions.

  20. Cesium chloride protects cerebellar granule neurons from apoptosis induced by low potassium.

    Science.gov (United States)

    Zhong, Jin; Yao, Weiguo; Lee, Weihua

    2007-10-01

    Neuronal apoptosis plays a critical role in the pathogenesis of neurodegenerative disorders, and neuroprotective agents targeting apoptotic signaling could have therapeutic use. Here we report that cesium chloride, an alternative medicine in treating radiological poison and cancer, has neuroprotective actions. Serum and potassium deprivation induced cerebellar granule neurons to undergo apoptosis, which correlated with the activation of caspase-3. Cesium prevented both the activation of caspase-3 and neuronal apoptosis in a dose-dependent manner. Cesium at 8 mM increased the survival of neurons from 45 +/- 3% to 91 +/- 5% of control. Cesium's neuroprotection was not mediated by PI3/Akt or MAPK signaling pathways, since it was unable to activate either Akt or MAPK by phosphorylation. In addition, specific inhibitors of PI3 kinase and MAP kinase did not block cesium's neuroprotective effects. On the other hand, cesium inactivated GSK3beta by phosphorylation of serine-9 and GSK3beta-specific inhibitor SB415286 prevented neuronal apoptosis. These data indicate that cesium's neuroprotection is likely via inactivating GSK3beta. Furthermore, cesium also prevented H(2)O(2)-induced neuronal death (increased the survival of neurons from 72 +/- 4% to 89 +/- 3% of control). Given its relative safety and good penetration of the brain blood barrier, our findings support the potential therapeutic use of cesium in neurodegenerative diseases.

  1. Radioactive cesium dynamics derived from hydrographic observations in the Abukuma River Estuary, Japan.

    Science.gov (United States)

    Kakehi, Shigeho; Kaeriyama, Hideki; Ambe, Daisuke; Ono, Tsuneo; Ito, Shin-ichi; Shimizu, Yugo; Watanabe, Tomowo

    2016-03-01

    Large quantities of radioactive materials were released into the air and the ocean as a result of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, caused by the 2011 Tohoku earthquake and the subsequent major tsunami off the Pacific coast. There is much concern about radioactive contamination in both the watershed of the Abukuma River, which flows through Fukushima Prefecture, and its estuary, where it discharges into the sea in Miyagi Prefecture. We investigated radioactive cesium dynamics using mixing diagrams obtained from hydrographic observations of the Abukuma River Estuary. Particulate radioactive cesium dominates the cesium load in the river, whereas the dissolved form dominates in the sea. As the salinity increased from <0.1 to 0.1-2.3, the mixing diagram showed that dissolved radioactive cesium concentrations increased, because of desorption. Desorption from suspended particles explained 36% of dissolved radioactive cesium in estuarine water. However, the dissolved and particulate radioactive cesium concentrations in the sea decreased sharply because of dilution. It is thought that more than 80% of the discharged particulate radioactive cesium was deposited off the river mouth, where the radioactive cesium concentrations in sediment were relatively high (217-2440 Bq kg(-1)). Radioactive cesium that was discharged to the sea was transported southward by currents driven by the density distribution.

  2. Cesium Toxicity Alters MicroRNA Processing and AGO1 Expressions in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Il Lae Jung

    Full Text Available MicroRNAs (miRNAs are short RNA fragments that play important roles in controlled gene silencing, thus regulating many biological processes in plants. Recent studies have indicated that plants modulate miRNAs to sustain their survival in response to a variety of environmental stimuli, such as biotic stresses, cold, drought, nutritional starvation, and toxic heavy metals. Cesium and radio-cesium contaminations have arisen as serious problems that both impede plant growth and enter the food chain through contaminated plants. Many studies have been performed to define plant responses against cesium intoxication. However, the complete profile of miRNAs in plants during cesium intoxication has not been established. Here we show the differential expression of the miRNAs that are mostly down-regulated during cesium intoxication. Furthermore, we found that cesium toxicity disrupts both the processing of pri-miRNAs and AGONOUTE 1 (AGO1-mediated gene silencing. AGO 1 seems to be especially destabilized by cesium toxicity, possibly through a proteolytic regulatory pathway. Our study presents a comprehensive profile of cesium-responsive miRNAs, which is distinct from that of potassium, and suggests two possible mechanisms underlying the cesium toxicity on miRNA metabolism.

  3. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

  4. Effect of Cultivation Time and Medium Condition in Production of Bacterial Cellulose Nanofiber for Urease Immobilization

    Directory of Open Access Journals (Sweden)

    M. Pesaran

    2015-01-01

    Full Text Available A new nanoporous biomatrix originated from bacterial resources has been chosen for urease immobilization. Urease has been immobilized on synthesized bacterial cellulose nanofiber since this enzyme has a key role in nitrogen metabolism. Gluconacetobacter xylinum ATCC 10245 has been cultivated for synthesis of a nanofiber with the diameter of 30–70 nm. Different cultivation processes in the aspect of time and cultivation medium conditions were chosen to study the performance of immobilized enzyme on four types of bacterial cellulose nanofibers (BCNs. Urease immobilization into the nanofiber has been done in two steps: enzyme adsorption and glutaraldehyde cross-linking. The results showed that the immobilized enzymes were relatively active and highly stable compared to the control samples of free enzymes. Optimum pH was obtained 6.5 and 7 for different synthesized BCNs, while the optimum temperature for immobilized urease was 50°C. Finding of the current experiment illustrated that the immobilized enzyme in optimum condition lost its initial activity by 41% after 15 weeks.

  5. Radioactive cesium. Dynamics and transport in forestal food-webs; Radioaktivt cesium. Dynamik och transport i skogliga naeringsvaevar

    Energy Technology Data Exchange (ETDEWEB)

    Palo, T.; Nelin, P. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Animal Ecology; Bergman, R.; Nylen, T. [FOA NBC Defence, Umeaa (Sweden)

    1995-12-01

    This report summarises results from a radioecological study during 1994-1995 concerning turnover, redistribution and loss of radioactive Cesium (134 and 137) in boreal forest ecosystems, as well as uptake and transfer in important food-chains over moose, vole and vegetation. The basis for this report are 9 publications published 1994-95. These reports are presented in summary form. 9 refs, 17 figs.

  6. Kinetic Measurements for Enzyme Immobilization.

    Science.gov (United States)

    Cooney, Michael J

    2017-01-01

    Enzyme kinetics is the study of the chemical reactions that are catalyzed by enzymes, with a focus on their reaction rates. The study of an enzyme's kinetics considers the various stages of activity, reveals the catalytic mechanism of this enzyme, correlates its value to assay conditions, and describes how a drug or a poison might inhibit the enzyme. Victor Henri initially reported that enzyme reactions were initiated by a bond between the enzyme and the substrate. By 1910, Michaelis and Menten were advancing their work by studying the kinetics of an enzyme saccharase which catalyzes the hydrolysis of sucrose into glucose and fructose. They published their analysis and ever since the Michaelis-Menten equation has been used as the standard to describe the kinetics of many enzymes. Unfortunately, soluble enzymes must generally be immobilized to be reused for long times in industrial reactors. In addition, other critical enzyme properties have to be improved like stability, activity, inhibition by reaction products, and selectivity towards nonnatural substrates. Immobilization is by far the chosen process to achieve these goals.Although the Michaelis-Menten approach has been regularly adapted to the analysis of immobilized enzyme activity, its applicability to the immobilized state is limited by the barriers the immobilization matrix places upon the measurement of compounds that are used to model enzyme kinetics. That being said, the estimated value of the Michaelis-Menten coefficients (e.g., V max, K M) can be used to evaluate effects of immobilization on enzyme activity in the immobilized state when applied in a controlled manner. In this review enzyme activity and kinetics are discussed in the context of the immobilized state, and a few novel protocols are presented that address some of the unique constraints imposed by the immobilization barrier.

  7. In Situ Immobilization of Selenium in Sediment

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stewart, Thomas Austin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    This project focused on the use of a sorbent, carbonated apatite, to immobilize selenium in the environment. It is know that apatite will sorb selenium and based on the mechanism of sorption it is theorized that carbonated apatite will be more effective that pure apatite. Immobilization of selenium in the environment is through the use of a sorbent in a permeable reactive barrier (PRB). A PRB can be constructed by trenching and backfill with the sorbent or in the case of apatite as the sorbent formed in situ using the apatite forming solution of Moore (2003, 2004). There is very little data on selenium sorption by carbonated apatite in the literature. Therefore, in this work, the basic sorptive properties of carbonated apatite were investigated. Carbonated apatite was synthesized by a precipitation method and characterized. Batch selenium kinetic and equilibrium experiments were performed. The results indicate the carbonated apatite contained 9.4% carbonate and uptake of selenium as selenite was rapid; 5 hours for complete uptake of selenium vs. more than 100 hours for pure hydroxyapatite reported in the literature. Additionally, the carbonated apatite exhibited significantly higher distribution coefficients in equilibrium experiments than pure apatite under similar experimental conditions. The next phase of this work will be to seek additional funds to continue the research with the goal of eventually demonstrating the technology in a field application.

  8. Immobilization of tropizyme-P on amino-functionalized magnetic nanoparticles for fruit juice clarification

    Directory of Open Access Journals (Sweden)

    Mayur R Ladole

    2014-12-01

    Full Text Available Nowadays nanoparticles are widely used as a key tool for enzyme immobilization. Tropizyme-P, a pectolytic enzyme was successfully immobilized on amino functionalized magnetic nanoparticles (AMNPs using glutaraldehyde as a cross-linking agent at 15 mM concentration and 4h cross-linking time. The average size of the synthesized AMNPs was found below 80 nm by particle size analyzer. The binding of tropizyme-P on nanoparticles was confirmed by FTIR spectroscopy. SEM analysis revealed that there was no significance difference in the size of nanoparticles after tropizyme-P immobilization. XRD results showed no phase change in nanoparticles after enzyme immobilization. Physical parameters viz. pH and temperature were optimized. The pH was found to be same and there was shift in optimum temperature of immobilized tropizyme-P by 5ºC. Immobilized tropizyme-P had more thermal stability than free one. The kinetic studies revealed an increase in Vmax of the immobilized enzyme. Reusability of immobilized tropizyme-P was found to retain upto 85% of initial activity after sixth cycles of reuse.

  9. Green syntheses, v.1

    CERN Document Server

    Tundo, Pietro

    2014-01-01

    Introduction to the Green Syntheses SeriesPietro Tundo and John AndraosApplication of Material Efficiency Metrics to Assess Reaction Greenness-Illustrative Case Studies from Organic SynthesesJohn AndraosReaction 1: Synthesis of 3-Benzyl-5-Methyleneoxazolidin-2-one from N-Benzylprop-2-yn-1-Amine and CO2Qing-Wen Song and Liang-Nian HeReaction 2: Synthesis of the 5-Membered Cyclic Carbonates from Epoxides and CO2Qing-Wen Song, Liang-Nian HePart I: Green Methods for the Epoxidation of

  10. Nitrogenase activity of immobilized Azotobacter

    Energy Technology Data Exchange (ETDEWEB)

    Seyhan, E.; Kirwan, D.J.

    1979-02-01

    As part of a program to investigate the use of biological nitrogen fixation for fertilizer ammonia production, an investigation into the immobilization of the aerobic, nitrogen-fixing bacterium, Azotobacter vinelandii was undertaken. Immobilization was accomplished by adsorption onto an anionic exchange cellulose (Cellex E) with loadings as high as 10/sup 11/ cells/g resin. Immobilized cell preparations were tested under both batch and continuous-flow conditions. Nitrogenease activities as high as 4200 nmol/min g resin were observed as measured by the acetylene reduction assay. Immobilized cells retained their activity for as long as 117 hr in a continuous-flow reactor. Activity loss appeared to be related to the development of a variant strain.

  11. Treating Wastewater With Immobilized Enzymes

    Science.gov (United States)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  12. Radiocesium Adsorption By Zeolitic Materials Synthesized From Coal Fly Ash

    Directory of Open Access Journals (Sweden)

    Remenárová Lucia

    2014-06-01

    Full Text Available Brown coal fly ash derived from the combustion of brown-coal in power plant ENO Nováky (Slovak Republic was used as raw material for synthesis of zeolitic materials ZM1 and ZM3 by hydrothermal alternation with 1M NaOH and 3M NaOH, respectively. Fly ash and synthesized products were characterized using XRF and SEM-EDX analysis. Subsequently, zeolitic materials were tested as sorbents to remove Cs+ ions from aqueous solutions using radiotracer technique. Sorption of cesium by both types of zeolitic materials obeys Langmuir adsorption isotherm model. The maximum sorption capacities Qmax at pH 6.0 calculated from Langmuir isotherm were 1203 ± 65 μmol Cs+/ g for ZM1 and 1341 ± 66 μmol Cs+/ g for ZM3. The results showed that alkali treated fly ash can be used as effective sorbent for radiocesium removal from contaminated solutions

  13. Sol-Gel Synthesized Adsorbents for Metal Separation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A series of organo-ceramic adsorbents have been synthesized by a sol-gel processing technique for metal ion extraction. These adsorbents generally have significantly high metal uptake capacities, good physical-chemical stabilities, and well-designed pore geometries compared to other pre-existing metalchelating ceramic-based adsorbents. This work describes the synthesis and evaluation of pyrazole and calix[4]arene crown adsorbents for selective separation of platinum, palladium, and gold and cesium ions,respectively, from solutions. These materials exhibit mesoporous properties with high surface areas and pore volumes. The sol-gel synthesis starting with precursor silanes and titania results in gel particles of desired pore characteristics and high capacity and stability. Characterization studies, such as adsorption isotherms, breakthrough curves for fixed bed operation, and material stability, show promising results for applications to metal sepation.

  14. Synthesized night vision goggle

    Science.gov (United States)

    Zhou, Haixian

    2000-06-01

    A Synthesized Night Vision Goggle that will be described int his paper is a new type of night vision goggle with multiple functions. It consists of three parts: main observing system, picture--superimposed system (or Cathode Ray Tube system) and Charge-Coupled Device system.

  15. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    Science.gov (United States)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-02-02

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness.

  16. Rational Design of Cesium-Selective Ionophores and Chemosensors: Dihydrocalix[4]arene Crown-6 Ethers

    Energy Technology Data Exchange (ETDEWEB)

    Sachleben, Richard A.; Bryan, Jeffrey C.; Brown, Gilbert M.; Engle, Nancy L.; Haverlock, Tamara J.; Hay, Benjamin P.; Urvoas, Agathe; Moyer, Bruce A.

    2003-12-15

    Molecular mechanics calculations performed on calix[4]arene crown-6 ethers predict that the 1,3-dihydro derivatives will exhibit greater complementarity for potassium and cesium ions than the parent 1,3-dialkoxy calix crowns. The X-ray crystal structures of 1,3-alt bis-octyloxycalix[4]arene benzocrown-6 ether, dihydrocalix[4]arene benzocrown-6 ether, and the cesium nitrate complex of dihydrocalix[4]arene benzocrown-6 ether were determined. The cesium complex structure corresponds closely to the structure predicted by molecular mechanics. The dihydrocalix[4]arene crown-6 ethers exhibit enhanced cesium selectivity in the extraction of alkali metal salts and provide a platform for a highly sensitive and selective cesium chemosensor.

  17. [Variation in amount of radioactive cesium before and after cooking dry shiitake and beef].

    Science.gov (United States)

    Nabeshi, Hiromi; Tsutsumi, Tomoaki; Hachisuka, Akiko; Matsuda, Rieko

    2013-01-01

    We investigated the change of radioactive cesium content in food due to cooking in order to estimate the internal radiation exposure due to from radioactive materials in food. Our results revealed that soaking dry shiitake in water decreased the radioactive cesium content by about 50%, compared with that present in uncooked shiitake. Radioactive cesium in beef was decreased by about 10%, 12%, 60-65% and 80% by grilling, frying, boiling and stewing, respectively, compared to uncooked beef. For cooked beef, the decrease in the ratio of radioactive cesium was significantly different among the types of cooking. The decrease ratio of radioactive cesium in boiled and stewed beef was 8 times higher than that in grilled and fried beef.

  18. Characterizing optical dipole trap via fluorescence of trapped cesium atoms

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; GENG Tao; YAN Shubin; LI Gang; ZHANG Jing; WANG Junmin; PENG Kunchi; ZHANG Tiancai

    2006-01-01

    Optical dipole trap (ODT) is becoming an important tool of manipulating neutral atoms. In this paper ODT is realized with a far-off resonant laser beam strongly focused in the magneto-optical trap (MOT) of cesium atoms. The light shift is measured by simply monitoring the fluorescence of the atoms in the magneto-optical trap and the optical dipole trap simultaneously. The advantages of our experimental scheme are discussed, and the effect of the beam waist and power on the potential of dipole trap as well as heating rate is analyzed.

  19. Synthesis of glycinamides using protease immobilized magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Abha Sahu

    2016-12-01

    Full Text Available In the present investigation, Bacillus subtilis was isolated from slaughterhouse waste and screened for the production of protease enzyme. The purified protease was successfully immobilized on magnetic nanoparticles (MNPs and used for the synthesis of series of glycinamides. The binding and thermal stability of protease on MNPs was confirmed by FTIR spectroscopy and TGA analysis. The surface morphology of MNPs before and after protease immobilization was carried out using SEM analysis. XRD pattern revealed no phase change in MNPs after enzyme immobilization. The processing parameters for glycinamides synthesis viz. temperature, pH, and time were optimized using Response Surface Methodology (RSM by using Design Expert (9.0.6.2. The maximum yield of various amides 2 butyramidoacetic acid (AMD-1,83.4%, 2-benzamidoacetic acid (AMD-2,80.5% and 2,2′((carboxymethyl amino-2-oxoethyl-2-hydroxysuccinylbis(azanediyldiacetic acid (AMD-3,80.8% formed was observed at pH-8, 50 °C and 30 min. The synthesized immobilized protease retained 70% of the initial activity even after 8 cycles of reuse.

  20. Immobilized nickel hexacyanoferrate on activated carbons for efficient attenuation of radio toxic Cs(I) from aqueous solutions

    Science.gov (United States)

    Lalhmunsiama; Lalhriatpuia, C.; Tiwari, Diwakar; Lee, Seung-Mok

    2014-12-01

    The aim of this study is to immobilize nickel hexacyanoferrate onto the large surface of activated carbons (ACs) precursor to rice hulls and areca nut waste materials. These nickel hexacyanoferrate immobilized materials are then assessed in the effective attenuation of radio logically important cesium ions from aqueous solutions. The solid samples are characterized by the XRD analytical method and surface morphology is obtained from the SEM images. The batch reactor experiments show that an increase in sorptive pH (2.0-10.0) apparently not affecting the high percent uptake of Cs(I). Equilibrium modeling studies suggest that the data are reasonably and relatively fitted well to the Langmuir adsorption isotherm. Kinetic studies show that sorption process is fairly rapid and the kinetic data are fitted well to the pseudo-second order rate model. Increasing the background electrolyte concentration from 0.001 to 0.1 mol/L NaCl causes insignificant decrease in Cs(I) removal which infers the higher selectivity of these materials for Cs(I) from aqueous solutions. Further, the column reactor operations enable to obtain the breakthrough data which are then fitted to the Thomas non-linear equation as to obtain the loading capacity of column for Cs(I). The results show that the modified materials show potential applicability in the attenuation of radio toxic cesium from aqueous solution.

  1. Site-specific immobilization of enzymes on magnetic nanoparticles and their use in organic synthesis.

    Science.gov (United States)

    Yu, Ching-Ching; Kuo, Yu-Ying; Liang, Chien-Fu; Chien, Wei-Ting; Wu, Huan-Ting; Chang, Tsung-Che; Jan, Fan-Dan; Lin, Chun-Cheng

    2012-04-18

    Magnetic nanoparticles (MNPs) are attractive materials that serve as a support for enzyme immobilization and facilitate separations by applying an external magnetic field; this could facilitate the recycling of enzymes and broaden their applications in organic synthesis. Herein, we report the methods for the immobilization of water-soluble and membrane-bound enzymes, and the activity difference between free and immobilized enzymes is discussed. Sialyltransferase (PmST1, from Pasteurella multocida ) and cytidine monophosphate (CMP)-sialic acid synthetase (CSS, from Neisseria meningitides ) were chosen as water-soluble enzymes and expressed using an intein expression system. The enzymes were site-specifically and covalently immobilized on PEGylated-N-terminal cysteine MNPs through native chemical ligation (NCL). Increasing the length of the PEG linker between the enzyme and the MNP surface increased the activity of the immobilized enzymes relative to the free parent enzymes. In addition, the use of a fluorescent acceptor tag for PmST1 affected enzyme kinetics. In contrast, sialyltransferase from Neisseria gonorrheae (NgST, a membrane-bound enzyme) was modified with a biotin-labeled cysteine at the C-terminus using NCL, and the enzyme was then assembled on streptavidin-functionalized MNPs. Using a streptavidin-biotin interaction, it was possible to immobilize NgST on a solid support under mild ligation conditions, which prevented the enzyme from high-temperature decomposition and provided an approximately 2-fold increase in activity compared to other immobilization methods on MNPs. Finally, the ganglioside GM3-derivative (sialyl-lactose derivative) was synthesized in a one-pot system by combining the use of immobilized PmST1 and CSS. The enzymes retained 50% activity after being reused ten times. Furthermore, the results obtained using the one-pot two-immobilized-enzyme system demonstrated that it can be applied to large-scale reactions with acceptable yields and

  2. Adsorption of sodium and cesium on aggregates of C60

    Science.gov (United States)

    Harnisch, Martina; Daxner, Matthias; Scheier, Paul; Echt, Olof

    2016-09-01

    We explore the formation of C60 sodium and C60 cesium complexes in superfluid helium nanodroplets. Anomalies in mass spectra of these doped droplets reveal anomalies in the stability of ions. (C60) m Cs+ n ions ( m ≤ 6) are particularly abundant if they contain n = 6 m + 1 cesium atoms; (C60) m Cs2+ n dications ( m ≤ 3 or 5) are abundant if n = 6 m + 2. These findings are consistent with the notion that alkali metal atoms (A) transfer their valence electrons into the three-fold degenerate lowest unoccupied orbital of C60, resulting in particularly stable C60A6 building blocks. However, (C60) 4CsCs2+ n dications display an entirely different pattern; instead of an expected anomaly at n = 6 × 4 + 2 = 26 we observe a strong odd-even alternation starting at n = 6. Also surprising is the effect of adding one H2O or CO2 molecule to (C60) m Cs n mono- or dications; anomalies shift by two units as if the impurity were acting as an acceptor for two valence electrons from the alkali metal atoms.

  3. Kelvin probe studies of cesium telluride photocathode for AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, Eric E., E-mail: ewisniew@anl.gov [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Velazquez, Daniel [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Yusof, Zikri, E-mail: zyusof@hawk.iit.edu [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Spentzouris, Linda; Terry, Jeff [Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Sarkar, Tapash J. [Rice University, 6100 Main, Houston, TX 77005 (United States); Harkay, Katherine [Accelerator Science Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States)

    2013-05-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (≈50nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating. -- Highlights: ► The correlation between Quantum Efficiency (QE) and work function. ► How QE and work function evolve together. ► Rejuvenation of the photocathode via heating and the effect on work function. ► The effects on the work function due to exposure to UV light.

  4. Structure and bonding in crystalline cesium uranyl tetrachloride under pressure.

    Science.gov (United States)

    Osman, Hussien H; Pertierra, Pilar; Salvadó, Miguel A; Izquierdo-Ruiz, F; Recio, J M

    2016-07-21

    A thorough investigation of pressure effects on the structural properties of crystalline cesium uranyl chloride was performed by means of first-principles calculations within the density functional theory framework. Total energies, equilibrium geometries and vibrational frequencies were computed at selected pressures up to 50 GPa. Zero pressure results present good agreement with available experimental and theoretical data. Our calculated equation of state parameters reveal that Cs2UO2Cl4 is a high compressible material, similar to other ionic compounds with cesium cations, and displays a structural anisotropic behavior guided by the uranyl moiety. An unexpected variation of the U-O bond length, dUO, is detected as pressure is applied. It leads to a dUO-stretching frequency relationship that cannot be described by the traditional Badger's rule. Interestingly enough, it can be explained in terms of a change in the main factor controlling dUO. At low pressure, the charge transferred to the uranyl cation induces an increase of the bond length and a red shift of the stretching frequencies, whereas it is the mechanical effect of the applied pressure above 10 GPa that is the dominant factor that leads to a shortening of dUO and a blue shift of the stretching frequencies.

  5. Spectrally selective optical pumping in Doppler-broadened cesium atoms

    Institute of Scientific and Technical Information of China (English)

    Zhang Jun-Hai; Zeng Xian-Jin; Li Qing-Meng; Huang Qiang; Sun Wei-Min

    2013-01-01

    The D1 line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations.The process,described by a three-level model with the A scheme,shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms.The |Fg =3> → |Fe-4> resonance pumping can result in the ground state |Fg =4,mF =4> sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state Fg =4.To enhance the anisotropy in the ground state,we suggest employing dichromatic optical HF pumping by adding a laser to excite D1 line |Fg =4> → |Fe =3>transition,in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth's average magnetic field.

  6. Immobile Complex Verbs in Germanic

    DEFF Research Database (Denmark)

    Vikner, Sten

    2005-01-01

    Certain complex verbs in Dutch, German, and Swiss German do not undergo verb movement. The suggestion to be made in this article is that these ‘‘immobile'' verbs have to fulfill both the requirements imposed on complex verbs of the V° type (=verbs with non-separable prefixes) and the requirements...... are immobile, - why such verbs are not found in Germanic VO-languages such as English and Scandinavian.......Certain complex verbs in Dutch, German, and Swiss German do not undergo verb movement. The suggestion to be made in this article is that these ‘‘immobile'' verbs have to fulfill both the requirements imposed on complex verbs of the V° type (=verbs with non-separable prefixes) and the requirements...

  7. Equilibrium, kinetic and thermodynamic study of cesium adsorption onto nanocrystalline mordenite from high-salt solution.

    Science.gov (United States)

    Lee, Keun-Young; Park, Minsung; Kim, Jimin; Oh, Maengkyo; Lee, Eil-Hee; Kim, Kwang-Wook; Chung, Dong-Yong; Moon, Jei-Kwon

    2016-05-01

    In this study, the equilibrium, kinetics and thermodynamics of cesium adsorption by nanocrystalline mordenite were investigated under cesium contamination with high-salt solution, simulating the case of an operation and decommissioning of nuclear facilities or an accident during the processes. The adsorption rate constants were determined using a pseudo second-order kinetic model. The kinetic results strongly demonstrated that the cesium adsorption rate of nano mordenite is extremely fast, even in a high-salt solution, and much faster than that of micro mordenite. In the equilibrium study, the Langmuir isotherm model fit the cesium adsorption data of nano mordenite better than the Freundlich model, which suggests that cesium adsorption onto nano mordenite is a monolayer homogeneous adsorption process. The obtained thermodynamic parameters indicated that the adsorption involved a very stable chemical reaction. In particular, the combination of rapid particle dispersion and rapid cesium adsorption of the nano mordenite in the solution resulted in a rapid and effective process for cesium removal without stirring, which may offer great advantages for low energy consumption and simple operation.

  8. Generalized colloidal synthesis of high-quality, two-dimensional cesium lead halide perovskite nanosheets and their applications in photodetectors

    Science.gov (United States)

    Lv, Longfei; Xu, Yibing; Fang, Hehai; Luo, Wenjin; Xu, Fangjie; Liu, Limin; Wang, Biwei; Zhang, Xianfeng; Yang, Dong; Hu, Weida; Dong, Angang

    2016-07-01

    All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) are emerging as an important class of semiconductor materials with superior photophysical properties and wide potential applications in optoelectronic devices. So far, only a few studies have been conducted to control the shape and geometry of CsPbX3 NCs. Here we report a general approach to directly synthesize two-dimensional (2D) CsPbX3 perovskite and mixed perovskite nanosheets with uniform and ultrathin thicknesses down to a few monolayers. The key to the high-yield synthesis of perovskite nanosheets is the development of a new Cs-oleate precursor. The as-synthesized CsPbX3 nanosheets exhibit bright photoluminescence with broad wavelength tunability by composition modulation. The excellent optoelectronic properties of CsPbX3 nanosheets combined with their unique 2D geometry and large lateral dimensions make them ideal building blocks for building functional devices. To demonstrate their potential applications in optoelectronics, photodetectors based on CsPbBr3 nanosheets are fabricated, which exhibit high on/off ratios with a fast response time.All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) are emerging as an important class of semiconductor materials with superior photophysical properties and wide potential applications in optoelectronic devices. So far, only a few studies have been conducted to control the shape and geometry of CsPbX3 NCs. Here we report a general approach to directly synthesize two-dimensional (2D) CsPbX3 perovskite and mixed perovskite nanosheets with uniform and ultrathin thicknesses down to a few monolayers. The key to the high-yield synthesis of perovskite nanosheets is the development of a new Cs-oleate precursor. The as-synthesized CsPbX3 nanosheets exhibit bright photoluminescence with broad wavelength tunability by composition modulation. The excellent optoelectronic properties of CsPbX3 nanosheets

  9. Immobilization of Burkholderia sp. lipase on a ferric silica nanocomposite for biodiesel production.

    Science.gov (United States)

    Tran, Dang-Thuan; Chen, Ching-Lung; Chang, Jo-Shu

    2012-04-15

    In this work, lipase produced from an isolated strain Burkholderia sp. C20 was immobilized on magnetic nanoparticles to catalyze biodiesel synthesis. Core-shell nanoparticles were synthesized by coating Fe(3)O(4) core with silica shell. The nanoparticles treated with dimethyl octadecyl [3-(trimethoxysilyl) propyl] ammonium chloride were used as immobilization supporters. The Burkholderia lipase was then bound to the synthesized nanoparticles for immobilization. The protein binding efficiency on alkyl-functionalized Fe(3)O(4)-SiO(2) was estimated as 97%, while the efficiency was only 76% on non-modified Fe(3)O(4)-SiO(2). Maximum adsorption capacity of lipase on alkyl-functionalized Fe(3)O(4)-SiO(2) was estimated as 29.45 mg g(-1) based on Langmuir isotherm. The hydrolytic kinetics (using olive oil as substrate) of the lipase immobilized on alkyl-grafted Fe(3)O(4)-SiO(2) followed Michaelis-Menten model with a maximum reaction rate and a Michaelis constant of 6251 Ug(-1) and 3.65 mM, respectively. Physical and chemical properties of the nanoparticles and the immobilized lipase were characterized by Brunauer-Emmett-Teller (BET) analysis, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). Moreover, the immobilized lipase was used to catalyze the transesterification of olive oil with methanol to produce fatty acid methyl esters (FAMEs), attaining a FAMEs conversion of over 90% within 30 h in batch operation when 11 wt% immobilized lipase was employed. The immobilized lipase could be used for ten cycles without significant loss in its transesterification activity.

  10. Preliminary Evaluation of Cesium Distribution for Wet Sieving Process Planned for Soil Decontamination in Japan - 13104

    Energy Technology Data Exchange (ETDEWEB)

    Enokida, Y.; Tanada, Y.; Hirabayashi, D. [Graduate School of Engineering, 1 Furo-cho Nagoya-shi, Aichi-ken, 4648603 (Japan); Sawada, K. [EcoTopia Science Institute, Nagoya University, 1 Furo-cho Nagoya-shi, Aichi-ken, 4648603 (Japan)

    2013-07-01

    For the purpose of decontaminating radioactive cesium from a huge amount of soil, which has been estimated to be 1.2x10{sup 8} m{sup 3} by excavating to a 5-cm depth from the surface of Fukushima Prefecture where a severe nuclear accident occurred at TEPCO's power generating site and has emitted a significant amount of radioactive materials, mainly radioactive cesium, a wet sieving process was selected as one of effective methods available in Japan. Some private companies have demonstrated this process for soil treatment in the Fukushima area by testing at their plants. The results were very promising, and a full-fledged application is expected to follow. In the present study, we spiked several aqueous samples containing soil collected from an industrial wet sieving plant located near our university for the recycling of construction wastes with non-radioactive cesium hydroxide. The present study provides scientific data concerning the effectiveness in volume reduction of the contaminated soil by a wet sieving process as well as the cesium distribution between the liquid phase and clay minerals for each sub-process of the full-scale one, but a simulating plant equipped with a process of coagulating sedimentation and operational safety fundamentals for the plant. Especially for the latter aspect, the study showed that clay minerals of submicron size strongly bind a high content of cesium, which was only slightly removed by coagulation with natural sedimentation (1 G) nor centrifugal sedimentation (3,700 G) and some of the cesium may be transferred to the effluent or recycled water. By applying ultracentrifugation (257,000 G), most of submicron clay minerals containing cesium was removed, and the cesium amount which might be transferred to the effluent or recycled water, could be reduced to less than 2.3 % of the original design by the addition of a cesium barrier consisting of ultracentrifugation or a hollow fiber membrane. (authors)

  11. Synthesis of Dopamine and Serotonin Derivatives for Immobilization on a Solid Support

    DEFF Research Database (Denmark)

    Funder, Erik Daa; Jensen, Anne Bjørnskov; Tørring, Thomas;

    2012-01-01

    The two important neurotransmitters dopamine and serotonin are synthesized with short PEG tethers and immobilized on a magnetic solid support. The tether is attached to the aromatic moiety of the neurotransmitters to conserve their original functional groups. This approach causes minimal alterati...

  12. High voltage holding in the negative ion sources with cesium deposition

    Energy Technology Data Exchange (ETDEWEB)

    Belchenko, Yu.; Abdrashitov, G.; Ivanov, A.; Sanin, A.; Sotnikov, O., E-mail: O.Z.Sotnikov@inp.nsk.su [Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2016-02-15

    High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed.

  13. Historical Cost Curves for Hydrogen Masers and Cesium Beam Frequency and Timing Standards

    Science.gov (United States)

    Remer, D. S.; Moore, R. C.

    1985-01-01

    Historical cost curves were developed for hydrogen masers and cesium beam standards used for frequency and timing calibration in the Deep Space Network. These curves may be used to calculate the cost of future hydrogen masers or cesium beam standards in either future or current dollars. The cesium beam standards are decreasing in cost by about 2.3% per year since 1966, and hydrogen masers are decreasing by about 0.8% per year since 1978 relative to the National Aeronautics and Space Administration inflation index.

  14. The Diagnostics Of Hydrogen-Cesium Plasma Using Fully Relativistic Electron Impact Cross Sections

    Science.gov (United States)

    Priti, Priti; Dipti, Dipti; Gangwar, Reetesh; Srivastava, Rajesh

    2016-10-01

    Electron excitation cross-sections and rate coefficients have been calculated using fully relativistic distorted wave theory for several fine-structure transitions from the ground as well as excited states of cesium atom in the wide range of incident electron energy. These processes play dominant role in low pressure hydrogen-cesium plasma relevant to the negative ion based neutral beam injectors for the ITER project. The calculated cross-sections are used to construct a reliable collisional radiative (CR) model to characterize the hydrogen-cesium plasma. The calculated plasma parameters are compared with the available experimental and theoretical results.

  15. Comparative analysis of cesium and potassium uptake in onion Allium cepa L.

    Science.gov (United States)

    Urban, P. Ł.; Bystrzejewska-Piotrowska, G.

    2003-01-01

    Cesium uptake in onion (from 0.3 mM CsCl solution traced with 137CsCl) has been examined. The highest uptake occurred at pH 4-5 and it decreased with increasing pH. The intensity of Cs translocation depended on acidity of the solution. For acidic solutions, translocation of cesium into bulbs and leaves was greater than in case of alkaline solutions, where most of the cesium remained in the roots. Addition of potassium into the solutions (millimolar K concentrations) inhibits Cs uptake. The potassium pH-influx/efflux characteristic does not coincide with the Cs uptake.

  16. Fission of Multiply Charged Cesium and Potassium Clusters in Helium Droplets - Approaching the Rayleigh Limit

    OpenAIRE

    Renzler, Michael; Harnisch, Martina; Daxner, Matthias; Kranabetter, Lorenz; Kuhn, Martin; Scheier, Paul; Echt, Olof

    2016-01-01

    Electron ionization of helium droplets doped with cesium or potassium results in doubly and, for cesium, triply charged cluster ions. The smallest observable doubly charged clusters are $Cs_{9}^{2+}$ and $K_{11}^{2+}$; they are a factor two smaller than reported previously. The size of potassium dications approaches the Rayleigh limit nRay for which the fission barrier is calculated to vanish, i.e. their fissilities are close to 1. Cesium dications are even smaller than nRay, implying that th...

  17. Test procedures and instructions for single shell tank saltcake cesium removal with crystalline silicotitanate

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, J.B.

    1997-01-07

    This document provides specific test procedures and instructions to implement the test plan for the preparation and conduct of a cesium removal test, using Hanford Single Shell Tank Saltcake from tanks 24 t -BY- I 10, 24 1 -U- 108, 24 1 -U- 109, 24 1 -A- I 0 1, and 24 t - S-102, in a bench-scale column. The cesium sorbent to be tested is crystalline siticotitanate. The test plan for which this provides instructions is WHC-SD-RE-TP-024, Hanford Single Shell Tank Saltcake Cesium Removal Test Plan.

  18. Effect of Rare Earth Elements on Exchange Performances of Cesium Ion-Sieve

    Institute of Scientific and Technical Information of China (English)

    张惠源; 王榕树; 林灿生; 张先业

    2003-01-01

    The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particular, the effects of neodymium on the cesium ion exchange and the Cs+ selectivity variation on Cs-IS owing to introduction of rare earth elements into HLLW were studied. Though rare earth elements exhibit a small influence on the distribution coefficient for Cs+, they impair Cs-exchange capacity of Cs-IS to some extent. This interruption on the selectivity to Cs+ can be significantly eliminated provided an appropriate ratio of liquid to solid V:m is used.

  19. Application of Cesium isotopes in daily life; Aplicacoes dos isotopos do Cesio no cotidiano

    Energy Technology Data Exchange (ETDEWEB)

    Jordao, B.O.; Quaresma, D.S.; Carvalho, R.J., E-mail: bjordan@on.br, E-mail: dansq@on.br, E-mail: carvalho@on.br [Observatorio Nacional (ON/LPTF), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Tempo e Frequencia; Peixoto, J.G.P., E-mail: guilherm@ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Metrologia das Radiacoes Ionizantes

    2014-07-01

    In the world of science, the desire of the scientific community to discover new chemical elements is crucial for the development of new technologies in various fields of knowledge. And the main chemical element addressed by this article is Cesium, but specifically {sup 133}Cesium isotope and radioisotope {sup 137}Cesium, exemplifying their physical and chemical characteristics, and their applications. This article will also show how these isotopes have provided researchers a breakthrough in the field of radiological medicine and in time and frequency metrology. (author)

  20. First-principles study of cesium adsorption to weathered micaceous clay minerals

    Science.gov (United States)

    Okumura, Masahiko; Nakamura, Hiroki; Machida, Masahiko

    2014-05-01

    A large amount of radioactive nuclides was produced into environment due to the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Residents near FDNPP were suffering from radioactive cesium and then evacuated, because which has long half-life and is retained by surface soil for long time. The Japanese government has been decontaminating the cesium by removing the surface soil in order to return them to their home. This decontamination method is very effective, but which produces huge amount of waste soil. This becomes another big problem in Fukushima, because it is not easy to find large storage sites. Then effective and economical methods to reduce the volume of the waste soil are needed. However, it has not been invented yet. One of the reasons is lack of knowledge about microscopic process of adsorption/desorption of cesium to/from soil. It is known that weathered micaceous clay minerals play crucial role on adsorption and retention of cesium. They are expected to have special sorption sites, called frayed edge sites (FESs), which adsorb cesium selectively and irreversibly. Properties of FES have been intensely investigated by experiments. But microscopic details of the adsorption process on FES are still unclear. Because direct observation of the process with current experimental techniques is quite difficult. We investigated the adsorption of cesium to FES in muscovite, which is a typical micaceous clay mineral, via first-principles calculations (density functional theory). We made a minimal model of FES and evaluate the energy difference before and after cesium adsorption to FES. This is the first numerical modeling of FES. It was shown that FES does adsorb cesium if the weathering of muscovite has been weathered. In addition, we revealed the mechanism of cesium adsorption to FES, which is competition between ion radius of cesium and the degree of weathering. I plan to discuss volume reduction of the waste soil based on our result. Reference M. Okumura

  1. A New Pumping-Probing Scheme for the Optically Pumped Cesium Beam Frequency Standard

    Institute of Scientific and Technical Information of China (English)

    陈景标; 朱程锦; 王凤芝; 杨东海

    2001-01-01

    A new pumping-probing scheme for the optically pumped cesium beam frequency standard has been experimentally tested in our laboratory. The stability of the optically pumped cesium beam frequency standard was measured by comparing its 10 MHz output with an HP5071A commercial cesium atomic clock. The result shows that the frequency stability for the 1 s and 30000s sample times are 1.2 × 10-11 and 3.7 × 10-13, respectively. It was proved that the new pumping scheme works well.

  2. Effect of poly(vinyl acetate-acrylamide) microspheres properties and steric hindrance on the immobilization of Candida rugosa lipase.

    Science.gov (United States)

    Zhang, Dong-Hao; Yuwen, Li-Xia; Li, Chao; Li, Ya-Qiong

    2012-11-01

    Poly(vinyl acetate-acrylamide) microspheres were synthesized in the absence or presence of isooctane via suspension polymerization and utilized as carriers to immobilize Candida rugosa lipase. When the hydrophobic/hydrophilic surface characteristics of the microspheres were modified by changing the ratio of vinyl acetate (hydrophobic monomer) to acrylamide (hydrophilic monomer) from 50:50 to 86:24, the immobilization ratio changed from 45% to 92% and the activity of the immobilized lipase increased from 202.5 to 598.0 U/g microsphere. Excessive lipase loading caused intermolecular steric hindrance, which resulted in a decline in lipase activity. The maximum specific activity of the immobilized lipase (4.65 U/mg lipase) was higher than that of free lipase (3.00 U/mg lipase), indicating a high activity recovery during immobilization.

  3. a Biokinetic Model for CESIUM-137 in the Fetus

    Science.gov (United States)

    Jones, Karen Lynn

    1995-01-01

    Previously, there was no method to determine the dose to the embryo, fetus, fetal organs or placenta from radionuclides within the embryo, fetus, or placenta. In the past, the dose to the fetus was assumed to be equivalent to the dose to the uterus. Watson estimated specific absorbed fractions from various maternal organs to the uterine contents which included the fetus, placenta, and amniotic fluid and Sikov estimated the absorbed dose to the embryo/fetus after assuming 1 uCi of radioactivity was made available to the maternal blood.^{1,2} However, this method did not allow for the calculation of a dose to individual fetal organs or the placenta. The radiation dose to the embryo or fetus from Cs-137 in the fetus and placenta due to a chronic ingestion by the mother was determined. The fraction of Cs-137 in the maternal plasma crossing the placenta to the fetal plasma was estimated. The absorbed dose from Cs-137 in each modelled fetal organ was estimated. Since there has been more research regarding potassium in the human body, and particularly in the pregnant woman, a biokinetic model for potassium was developed first and used as a basis and confirmation of the cesium model. Available pertinent information in physiology, embryology, biokinetics, and radiation dosimetry was utilized. Due to the rapid growth of the fetus and placenta, the pregnancy was divided into four gestational periods. The numerous physiological changes that occurred during pregnancy were considered and an appropriate biokinetic model was developed for each of the gestational periods. The amount of cesium in the placenta, embryo, and fetus was estimated for each period. The dose to the fetus from cesium deposited in the embryo or fetus and in the placenta was determined for each period using Medical Internal Radiation Dosimetry (MIRD) methodology. An uncertainty analysis was also performed to account for the variability of the parameters in the biokinetic model based on the experimental data

  4. Ion microscopy based on laser-cooled cesium atoms.

    Science.gov (United States)

    Viteau, M; Reveillard, M; Kime, L; Rasser, B; Sudraud, P; Bruneau, Y; Khalili, G; Pillet, P; Comparat, D; Guerri, I; Fioretti, A; Ciampini, D; Allegrini, M; Fuso, F

    2016-05-01

    We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a laser-cooled cesium beam and adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1-5keV range are obtained with a resolution around 40nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of the eV, offering great prospects for lithography, imaging and surface analysis.

  5. Coherence properties of nanofiber-trapped cesium atoms.

    Science.gov (United States)

    Reitz, D; Sayrin, C; Mitsch, R; Schneeweiss, P; Rauschenbeutel, A

    2013-06-14

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized ∼ 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time of T(2)(*) = 0.6 ms and an irreversible dephasing time of T(2)(') = 3.7 ms. By modeling the signals, we find that, for our experimental parameters, T(2)(*) and T(2)(') are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  6. Coherence properties of nanofiber-trapped cesium atoms

    CERN Document Server

    Reitz, D; Mitsch, R; Schneeweiss, P; Rauschenbeutel, A

    2013-01-01

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time $T_2^\\ast=0.6$ ms and an irreversible dephasing time $T_2^\\prime=3.7$ ms. By theoretically modelling the signals, we find that, for our experimental parameters, $T_2^\\ast$ and $T_2^\\prime$ are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  7. Morphological effects in the quantum yield of cesium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, J. [Ecole Politechnique Federale, Lausanne (Switzerland). DP-IPA PH-Ecublens; Barbo, F. [Sincrotrone Trieste SpA, Padriciano 99, 34012 Trieste (Italy); Bertolo, M. [Sincrotrone Trieste SpA, Padriciano 99, 34012 Trieste (Italy); Bianco, A. [Sincrotrone Trieste SpA, Padriciano 99, 34012 Trieste (Italy); Braem, A. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Cerasari, S. [Sincrotrone Trieste SpA, Padriciano 99, 34012 Trieste (Italy); Coluzza, C. [Ecole Politechnique Federale, Lausanne (Switzerland). DP-IPA PH-Ecublens; Dell`Orto, T. [Ecole Politechnique Federale, Lausanne (Switzerland). DP-IPA PH-Ecublens; Fontana, S. [Sincrotrone Trieste SpA, Padriciano 99, 34012 Trieste (Italy); Margaritondo, G. [Ecole Politechnique Federale, Lausanne (Switzerland). DP-IPA PH-Ecublens; Nappi, E. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Paic, G. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Piuz, F. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments; Sanjines, R. [Ecole Politechnique Federale, Lausanne (Switzerland). DP-IPA PH-Ecublens; Scognetti, T. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Sgobba, S. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments

    1995-07-15

    We demonstrated that polycrystalline cesium iodide (CsI) on large area Ni/Au coated printed board provides a quantum efficiency (QE) higher by a factor of 2 than the films deposited on the standard Cu/Au printed circuits. This is the most important result of the present systematic study of the QE lateral inhomogeneity for CsI on different substrates. We found a strong correlation between the QE lateral variation and the morphological homogeneity of the films. The QE was measured by UV photoelectron emission microscopy and spatially resolved X-ray photoemission, and the morphology studies were performed by secondary electron microscopy, X-ray diffraction and scanning tunneling microscopy. (orig.).

  8. Hyperfine relaxation of an optically pumped cesium vapor

    Energy Technology Data Exchange (ETDEWEB)

    Tornos, J.; Amare, J.C.

    1986-07-01

    The relaxation of hyperfine orientation indirectly induced by optical pumping with a sigma-polarized D/sub 1/-light in a cesium vapor in the presence of Ar is experimentally studied. The detection technique ensures the absence of quadrupole relaxation contributions in the relaxation signals. The results from the dependences of the hyperfine relaxation rate on the temperature and argon pressure are: diffusion coefficient of Cs in Ar, D/sub 0/ = 0.101 +- 0.010 cm/sup 2/s/sup -1/ at 0/sup 0/C and 760 Torr; relaxation cross section by Cs-Ar collisions, sigma/sub c/ = (104 +- 5) x 10/sup -23/ cm/sup 2/; relaxation cross section by Cs-Cs (spin exchange) collisions, sigma/sub e//sub x/ = (1.63 +- 0.13) x 10/sup -14/ cm/sup 2/.

  9. New Efimov resonances in an ultracold cesium gas

    Energy Technology Data Exchange (ETDEWEB)

    Zenesini, Alessandro; Berninger, Martin; Besler, Stefan; Naegerl, Hanns-Christoph; Ferlaino, Francesca [Institut fuer Experimentalphysik, Universitaet Innsbruck, 6020 Innsbruck (Austria); Huang, Bo; Grimm, Rudolf [Institut fuer Experimentalphysik, Universitaet Innsbruck, 6020 Innsbruck (Austria); Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck (Austria)

    2011-07-01

    Efimov trimer states represent the paradigm of universality in few-body physics. Although these exotic three-body weakly-bound states have been experimentally investigated in an increasing number of ultracold atomic systems, many fundamental aspects remain unclear. An intriguing open question is related to how short-range physics influences the Efimov effect in real systems. Short range contributions are commonly included in universal theory via a single parameter, known as ''three-body parameter''. An open question is whether this parameter is constant or whether it can vary significantly when Feshbach resonances are employed for interaction tuning. Cesium is a very promising candidate to address this issue because of the many broad and narrow Feshbach resonances with different partial-wave character. Our experimental results reveal new Efimov features close to different Feshbach resonances and shed new light on the three-body parameter.

  10. Mercury and cesium-137 in urban gray squirrels

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, J.H. (Univ. of Georgia, Athens); Davis, A.H.; Bigler, W.J.; Hoff, G.L.

    1980-08-01

    Recent emphasis upon the revitalization of major cities has underscored a need for urban wildlife management. Intensive management of the wildlife populations indigenous to metropolitan areas will enhance our quality of life in many ways. One important benefit is that certain species can serve as sensitive indicators of environmental change. The gray squirrel (Sciurus carolinensis) is usually abundant in cities and they are often subject to a variety of destructive environmental factors. In an attempt to evaluate the gray squirrel as an indicator of zoonoses and pollutants, the Health Program Office of the Department of Health and Rehabilitative Services conducted a multifaceted study in Jacksonvlle, Florida during 1974. This report presents baseline measurements of body burdens of mercury and cesium-137.

  11. Trade study for the disposition of cesium and strontium capsules

    Energy Technology Data Exchange (ETDEWEB)

    Claghorn, R.D.

    1996-03-01

    This trade study analyzes alternatives for the eventual disposal of cesium and strontium capsules currently stored at the Waste Encapsulation and Storage Facility as by-product. However, for purposes of this study, it is assumed that at some time in the future, the capsules will be declared high-level waste and therefore will require disposal at an offsite geologic repository. The study considered numerous alternatives and selected three for detailed analysis: (1) overpack and storage at high-level waste canister storage building, (2) overpack at the high-level waste vitrification facility followed by storage at a high-level waste canister storage building, and (3) blend capsule contents with other high-level waste feed streams and vitrify at the high-level waste vitrification facility.

  12. Fission of Multiply Charged Cesium and Potassium Clusters in Helium Droplets - Approaching the Rayleigh Limit

    CERN Document Server

    Renzler, Michael; Daxner, Matthias; Kranabetter, Lorenz; Kuhn, Martin; Scheier, Paul; Echt, Olof

    2016-01-01

    Electron ionization of helium droplets doped with cesium or potassium results in doubly and, for cesium, triply charged cluster ions. The smallest observable doubly charged clusters are $Cs_{9}^{2+}$ and $K_{11}^{2+}$; they are a factor two smaller than reported previously. The size of potassium dications approaches the Rayleigh limit nRay for which the fission barrier is calculated to vanish, i.e. their fissilities are close to 1. Cesium dications are even smaller than nRay, implying that their fissilities have been significantly overestimated. Triply charged cesium clusters as small as $Cs_{19}^{3+}$ are observed; they are a factor 2.6 smaller than previously reported. Mechanisms that may be responsible for enhanced formation of clusters with high fissilities are discussed.

  13. Biological effects of cesium-137 injected in beagle dogs of different ages

    Energy Technology Data Exchange (ETDEWEB)

    Nikula, K.J.; Muggenburg, B.A.; Griffith, W.C. [and others

    1995-12-01

    The toxicity of cesium-137 ({sup 137}Cs) in the Beagle dog was investigated at the Argonne National Laboratory (ANL) as part of a program to evaluate the biological effects of internally deposited radionuclides. The toxicity and health effects of {sup 137}Cs are important to understand because {sup 137}Cs is produced in large amounts in light-water nuclear reactors. Large quantities of cesium radioisotopes have entered the human food chain as a result of atmospheric nuclear weapons test, and additional cesium radioisotopes were released during the Chernobyl accident. Although the final analyses are not complete, three findings are significant: older dogs dies significantly earlier than juvenile and young adult dogs; greater occurrence of sarcomas in the cesium-137 injected dogs; the major nonneoplastic effect in dogs surviving beyond 52 d appears to be testicular atrophy.

  14. MODELING AN ION EXCHANGE PROCESS FOR CESIUM REMOVAL FROM ALKALINE RADIOACTIVE WASTE SOLUTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F; Luther Hamm, L; Sebastian Aleman, S; Johnston Michael, J

    2008-08-26

    The performance of spherical Resorcinol-Formaldehyde ion-exchange resin for the removal of cesium from alkaline radioactive waste solutions has been investigated through computer modeling. Cesium adsorption isotherms were obtained by fitting experimental data using a thermodynamic framework. Results show that ion-exchange is an efficient method for cesium removal from highly alkaline radioactive waste solutions. On average, two 1300 liter columns operating in series are able to treat 690,000 liters of waste with an initial cesium concentration of 0.09 mM in 11 days achieving a decontamination factor of over 50,000. The study also tested the sensitivity of ion-exchange column performance to variations in flow rate, temperature and column dimensions. Modeling results can be used to optimize design of the ion exchange system.

  15. Preparation, structure and application of a new ecomaterials cesium ion-sieve

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new ecomaterials cesium ion-sieve (Cs-IS), which has high selectivity to cesium and excellent acid resistance, is prepared with zirconyl molybdopyrophosphate as its matrix by specific chemical sieve-making means. Cs-IS has large exchange capacity ( 1.83mmol@g-1) and high distribution coefficient (4.09 x 104 mL@ L-1) in the medium of 3 mol@ L- 1 HNO3. In the static exchange with strongly acidic high-level radioactive liquid waste (HLLW) (3 mol@ L-1 HNO3), Cs-IS exhibits high exchange rate for cesium (above 96.53 % ) and large separation factor (greater than 958.41). These indicate the possible use of Cs-IS in cesium-137 selective removal and recovery from highly saline acidic HLLW system.

  16. Cold cesium molecules produced directly in a magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Zhang Hong-Shan; Ji Zhong-Hua; Yuan Jin-Peng; Zhao Yan-Ting; Ma Jie; Wang Li-Rong; Xiao Lian-Tuan; Jia Suo-Tang

    2011-01-01

    We report on the observation of ultracold ground electric-state cesium molecules produced directly in a magnetooptical trap with a good signal-to-noise ratio.These molecules arise from the photoassociation of magneto-optical trap lasers and they are detected by resonantly enhanced multiphoton ionization technology.The production rate of ultracold cesium molecules is up to 4× 104 s-1.We measure the characteristic time of the ground electric-state cesium molecules generated in the experiment and investigate the Cs2+ molecular ion intensity as a function of the trapping laser intensity and the ionization pulse laser energy.We conclude that the production of cold cesium molecules may be enhanced by using appropriate experimental parameters,which is useful for future experiments involving the production and trapping of ultracold ground electric-state molecules.

  17. Total deposition of cesium-137 measured in Finland during the exercise `RESUME 95` in August 1995

    Energy Technology Data Exchange (ETDEWEB)

    Geer, L.E. De; Vintersved, I.; Arntsing, R. [National Defence Research Establisment, Nuclear Detection Group, Stockholm (Sweden)

    1997-12-31

    In the exercise called `RESUME 95` the Nuclear Detection Group from the National Defence Research Establishment in Stockholm participated with field gamma ray measurements combined with soil sampling and profile measurements. The results are presented in this report for the measurements of cesium-137. We considered the measurements of cesium-137 at the airfield the most important part of the in-situ exercise. Data was of course collected also for cesium-134 and natural radionuclides but time has not permitted a full analysis of these radionuclides. The methodology would, however, be the same as applied for cesium-137. Less attention was paid for area II and due to limited personnel resources the search exercise was not fully carried out. (au).

  18. Calculation of fully relativistic cross sections for electron excitation of cesium atom and its application to the diagnostics of hydrogen-cesium plasma

    Science.gov (United States)

    Priti; Dipti; Gangwar, R. K.; Srivastava, R.

    2017-01-01

    Electron impact excitation cross-sections and rate coefficients have been calculated using fully relativistic distorted wave theory for several fine-structure transitions from the ground as well as excited states of cesium atom in the wide range of incident electron energy. These processes play dominant role in low pressure hydrogen-cesium plasma, which is relevant to the negative ion based neutral beam injectors for the ITER project. As an application, the calculated detailed cross-sections are used to construct a reliable collisional radiative (CR) model to characterize the hydrogen-cesium plasma. Other processes such as radiative population transfer, electron impact ionization and mutual neutralization of Cs+ ion with negative hydrogen ion along with their reverse processes are also taken into account. The calculated cross-sections and the extracted plasma parameters from the present model are compared with the available experimental and theoretical results.

  19. Effective immobilization of DNA for development of polypyrrole nanowires based biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Thi Luyen; Chu, Thi Xuan, E-mail: xuan@itims.edu.vn; Huynh, Dang Chinh; Pham, Duc Thanh; Luu, Thi Hoai Thuong; Mai, Anh Tuan, E-mail: tuan.maianh@hust.edu.vn

    2014-09-30

    Highlights: • Effective technique to immobilize probe DNA to the conducting polymer Polypyrrole nanowires (PPy NWs). • The PPy-NWs were electrochemically synthesized on the surface of the Pt electrodes using gelatin as the soft mold. • The DNA probe sequences were immobilized easily on the PPy NWs/Pt electrode using the adsorption method. • The DNA sensor has a low detection limit. - Abstract: This paper reports an easy technique for immobilization of the DNA to the conducting polymer polypyrrole nanowires (PPy NWs). The nanowires were electrochemically synthesized on the surface of working electrode in the presence of gelatin as a soft mold. The structure of obtained PPy NWs was investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and Surface Enhanced Raman Spectroscopy (SERS). The DNA strands were directly immobilized on the PPy NWs. The amino groups at the up-end of the PPy nanowires facilitate the linkage with the phosphate groups of the probe DNA. The DNA immobilization and hybridization were characterized by Electrochemical Impedance Spectroscopy (EIS). The initial results show that the sensor responses to 10 pM of DNA sequence in the solution.

  20. Editorial: Special Issue — Enzyme Immobilization

    Directory of Open Access Journals (Sweden)

    Roberto Fernandez-Lafuente

    2014-12-01

    Full Text Available Immobilization of enzymes and proteins is a requirement for many industrial enzyme applications, as this facilitates enzyme recovery and reuse. Bearing in mind this necessity, the coupling of immobilization to the improvement of other enzyme features has been pursued by many researchers, and nowadays immobilization is recognized as a tool to improve not only stability, but also enzyme selectivity, specificity, resistance to inhibition or chemical modifiers, etc. To achieve these overall improvements of enzymes’ properties via immobilization, it is necessary to both develop new immobilization systems suitable for these purposes, and to achieve a deeper knowledge of the mechanisms of interaction between enzymes and activated solids. That way, immobilization of enzymes, far being an old-fashioned methodology to just reuse these expensive biocatalysts, is a tool of continuous interest that requires a continuous effort to be exploited in all its potential. This special issue collects 23 papers reporting advances in the field of immobilization of enzymes.[...

  1. Biodiesel production with immobilized lipase: A review.

    Science.gov (United States)

    Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

    2010-01-01

    Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored.

  2. Export of radioactive cesium from agricultural fields under simulated rainfall in Fukushima.

    Science.gov (United States)

    Thai, Phong K; Suka, Yuma; Sakai, Masaru; Nanko, Kazuki; Yen, Jui-Hung; Watanabe, Hirozumi

    2015-06-01

    In this study, we investigated the impact of rainfall on runoff, soil erosion and consequently on the discharge of radioactive cesium in agricultural fields in Fukushima prefecture using a rainfall simulator. Simulated heavy rainfalls (50 mm h(-1)) generated significant runoff and soil erosion. The average concentration of radioactive cesium (the sum of (134)Cs and (137)Cs) in the runoff sediments was ∼3500 Bq kg(-1) dry soil, more than double the concentrations measured in the field soils which should be considered in studies using the (137)Cs loss to estimate long-term soil erosion. However, the estimated mass of cesium discharged through one runoff event was less than 2% of the cesium inventory in the field. This suggested that cesium discharge via soil erosion is not a significant factor in reducing the radioactivity of contaminated soils in Fukushima prefecture. However, the eroded sediment carrying radioactive cesium will deposit into the river systems and potentially pose a radioactivity risk for aquatic living organisms.

  3. Review and assessment of technologies for the separation of cesium from acidic media

    Energy Technology Data Exchange (ETDEWEB)

    Orth, R.J.; Brooks, K.P.; Kurath, D.E.

    1994-09-01

    A preliminary literature survey has been conducted to identify and evaluate methods for the separation of cesium from acidic waste. The most promising solvent extraction, precipitation, and ion exchange methods, along with some of the attributes for each method, are listed. The main criteria used in evaluating the separation methods were as follows: (1) good potential for cesium separation must be demonstrated (i.e., cesium decontamination factors on the order of 50 to 100). (2) Good selectivity for cesium over bulk components must be demonstrated. (3) The method must show promise for evolving into a practical and fairly simple process. (4) The process should be safe to operate. (5) The method must be robust (i.e., capable of separating cesium from various acidic waste types). (6) Secondary waste generation must be minimized. (7) The method must show resistance to radiation damage. The most promising separation methods did not necessarily satisfy all of the above criteria, thus key areas requiring further development are suggested for each method. The report discusses in detail these and other areas requiring further development, as well as alternative solvent extraction, precipitation, ion exchange, and {open_quote}other{close_quote} technologies that, based on current information, show less promise for the separation of cesium from acidic wastes because of significant process limitations. When appropriate, the report recommends areas of future development.

  4. Enhanced electronic injection in organic light-emitting diodes by incorporating silver nanoclusters and cesium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ying-Chung; Gao, Chia-Yuan [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Chen, Kan-Lin [Department of Electronic Engineering, Fortune Institute of Technology, Kaohsiung, Taiwan (China); Sze, Po-Wen [Department of Electro-Optical Science and Engineering, Kao Yuan University, Kaohsiung, Taiwan (China); Huang, Chien-Jung, E-mail: chien@nuk.edu.tw [Department of Applied Physics, National University of Kaohsiung, Kaohsiung, Taiwan (China)

    2015-10-01

    Highlights: • The localized electric field around SNCs is enhanced. • When the cesium carbonate/silver nanoclusters/cesium carbonate electron-injection structure replaces the cesium carbonate electron-injection structure, higher electron-injection ability is obtained. • The structure for efficient electron injection is critical to characteristics of the device. - Abstract: The influence of the cesium carbonate/silver nanoclusters/cesium carbonate electron-injection structure (CSC-EIS) on the performance of organic light-emitting diodes is investigated in this study. The silver nanoclusters (SNCs) are introduced between the electron-injection layers by means of thermal evaporation. When the CSC-EIS replaces the cesium carbonate electron-injection structure, higher electron-injection ability is obtained because the electron-injection barrier between the cathode and the electron-transport layer is remarkably reduced from 1.2 to 0 eV. In addition, surface plasmon resonance effect will cause the enhanced localized electric field around the SNCs, resulting that electron-injection ability is further enhanced from the cathode to the emitting layer.

  5. Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

    Energy Technology Data Exchange (ETDEWEB)

    Hang, T.; Nash, C. A.; Aleman, S. E.

    2012-09-19

    The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.

  6. Doclet To Synthesize UML

    Science.gov (United States)

    Barry, Matthew R.; Osborne, Richard N.

    2005-01-01

    The RoseDoclet computer program extends the capability of Java doclet software to automatically synthesize Unified Modeling Language (UML) content from Java language source code. [Doclets are Java-language programs that use the doclet application programming interface (API) to specify the content and format of the output of Javadoc. Javadoc is a program, originally designed to generate API documentation from Java source code, now also useful as an extensible engine for processing Java source code.] RoseDoclet takes advantage of Javadoc comments and tags already in the source code to produce a UML model of that code. RoseDoclet applies the doclet API to create a doclet passed to Javadoc. The Javadoc engine applies the doclet to the source code, emitting the output format specified by the doclet. RoseDoclet emits a Rose model file and populates it with fully documented packages, classes, methods, variables, and class diagrams identified in the source code. The way in which UML models are generated can be controlled by use of new Javadoc comment tags that RoseDoclet provides. The advantage of using RoseDoclet is that Javadoc documentation becomes leveraged for two purposes: documenting the as-built API and keeping the design documentation up to date.

  7. Ceramic Hosts for Fission Products Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Peter C Kong

    2010-07-01

    Natural spinel, perovskite and zirconolite rank among the most leach resistant of mineral forms. They also have a strong affinity for a large number of other elements and including actinides. Specimens of natural perovskite and zirconolite were radioisotope dated and found to have survived at least 2 billion years of natural process while still remain their loading of uranium and thorium . Developers of the Synroc waste form recognized and exploited the capability of these minerals to securely immobilize TRU elements in high-level waste . However, the Synroc process requires a relatively uniform input and hot pressing equipment to produce the waste form. It is desirable to develop alternative approaches to fabricate these durable waste forms to immobilize the radioactive elements. One approach is using a high temperature process to synthesize these mineral host phases to incorporate the fission products in their crystalline structures. These mineral assemblages with immobilized fission products are then isolated in a durable high temperature glass for periods measured on a geologic time scale. This is a long term research concept and will begin with the laboratory synthesis of the pure spinel (MgAl2O4), perovskite (CaTiO3) and zirconolite (CaZrTi2O7) from their constituent oxides. High temperature furnace and/or thermal plasma will be used for the synthesis of these ceramic host phases. Nonradioactive strontium oxide will be doped into these ceramic phases to investigate the development of substitutional phases such as Mg1-xSrxAl2O4, Ca1-xSrxTiO3 and Ca1-xSrxZrTi2O7. X-ray diffraction will be used to establish the crystalline structures of the pure ceramic hosts and the substitution phases. Scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDX) will be performed for product morphology and fission product surrogates distribution in the crystalline hosts. The range of strontium doping is planned to reach the full substitution of the divalent

  8. Laccase Immobilization on Poly(p-Phenylenediamine/Fe3O4 Nanocomposite for Reactive Blue 19 Dye Removal

    Directory of Open Access Journals (Sweden)

    Youxun Liu

    2016-08-01

    Full Text Available Magnetic poly(p-phenylenediamine (PpPD nanocomposite was synthesized via mixing p-phenylenediamine solution and Fe3O4 nanoparticles and used as a carrier for immobilized enzymes. Successful synthesis of PpPD/Fe3O4 nanofiber was confirmed by transmission electron microscopy and Fourier transform infrared spectroscopy. Laccase (Lac was immobilized on the surface of PpPD/Fe3O4 nanofiber through covalent bonding for reactive blue 19 dye removal. The immobilized Lac-nanofiber conjugates could be recovered from the reaction solution using a magnet. The optimum reaction pH and temperature for the immobilized Lac were 3.5 and 65 °C, respectively. The storage, operational stability, and thermal stability of the immobilized Lac were higher than those of its free counterpart. The dye removal efficiency of immobilized Lac was about 80% in the first 1 h of incubation, while that of free Lac was about 20%. It was found that the unique electronic properties of PpPD might underlie the high dye removal efficiency of immobilized Lac. Over a period of repeated operation, the dye removal efficiency was above 90% during the first two cycles and remained at about 43% after eight cycles. Immobilized Lac on PpPD/Fe3O4 nanofiber showed high stability, easy recovery, reuse capabilities, and a high removal efficiency for reactive blue 19 dye; therefore, it provides an optional tool for dye removal from wastewater.

  9. An Efficient, Recyclable, and Stable Immobilized Biocatalyst Based on Bioinspired Microcapsules-in-Hydrogel Scaffolds.

    Science.gov (United States)

    Zhang, Shaohua; Jiang, Zhongyi; Shi, Jiafu; Wang, Xueyan; Han, Pingping; Qian, Weilun

    2016-09-28

    Design and preparation of high-performance immobilized biocatalysts with exquisite structures and elucidation of their profound structure-performance relationship are highly desired for green and sustainable biotransformation processes. Learning from nature has been recognized as a shortcut to achieve such an impressive goal. Loose connective tissue, which is composed of hierarchically organized cells by extracellular matrix (ECM) and is recognized as an efficient catalytic system to ensure the ordered proceeding of metabolism, may offer an ideal prototype for preparing immobilized biocatalysts with high catalytic activity, recyclability, and stability. Inspired by the hierarchical structure of loose connective tissue, we prepared an immobilized biocatalyst enabled by microcapsules-in-hydrogel (MCH) scaffolds via biomimetic mineralization in agarose hydrogel. In brief, the in situ synthesized hybrid microcapsules encapsulated with glucose oxidase (GOD) are hierarchically organized by the fibrous framework of agarose hydrogel, where the fibers are intercalated into the capsule wall. The as-prepared immobilized biocatalyst shows structure-dependent catalytic performance. The porous hydrogel permits free diffusion of glucose molecules (diffusion coefficient: ∼6 × 10(-6) cm(2) s(-1), close to that in water) and retains the enzyme activity as much as possible after immobilization (initial reaction rate: 1.5 × 10(-2) mM min(-1)). The monolithic macroscale of agarose hydrogel facilitates the easy recycling of the immobilized biocatalyst (only by using tweezers), which contributes to the nonactivity decline during the recycling test. The fiber-intercalating structure elevates the mechanical stability of the in situ synthesized hybrid microcapsules, which inhibits the leaching and enhances the stability of the encapsulated GOD, achieving immobilization efficiency of ∼95%. This study will, therefore, provide a generic method for the hierarchical organization of (bio

  10. The effects of K+ growth conditions on the accumulation of cesium by the bacterium Thermus sp. TibetanG6

    Institute of Scientific and Technical Information of China (English)

    WANG; Hailei; KONG; Fanjing; ZHENG; Mianping

    2006-01-01

    The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K+ growth conditions. The effects of external pH and Na+ on the accumulation of cesium were also studied, and the mechanism involved was discussed. K+ regimes played an important role in the accumulation of cesium by the strain TibetanG6. The quantity of cesium accumulated (24 h) was much higher in K+-deficient regime than that in K+-sufficient regime. The pH and Na+ had different effects on the accumulation of cesium in the two K+ regimes. IR spectra analyses indicated that the biosorption is a process of homeostasis with cesium initially accumulated on the cell wall.

  11. Mesoporous silicas synthesis and application for lignin peroxidase immobilization by covalent binding method

    Institute of Scientific and Technical Information of China (English)

    Zunfang Hu; Longqian Xu; Xianghua Wen

    2013-01-01

    Immobilization of enzymes on mesoporous silicas (MS) allows for good reusability.MS with two-dimensional hexagonal pores in diameter up to 14.13 nm were synthesized using Pluronic P123 as template and 1,3,5-triisopropylbenzene as a swelling agent in acetate buffer.The surface of MS was modified by the silanization reagents 3-aminopropyltriethoxysilane.Lignin peroxidase (LiP) was successfully immobilized on the modified MS through covalent binding method by four agents:glutaraldehyde,1,4-phenylene diisothiocyanate,cyanotic chloride and water-soluble carbodiimide.Results showed that cyanotic chloride provided the best performance for LiP immobilization.The loaded protein concentration was 12.15 mg/g and the immobilized LiP activity was 812.9 U/L.Immobilized LiP had better pH stability.Acid Orange Ⅱ was used to examine the reusability of immobilized LiP,showing more than 50% of the dye was decolorized at the fifth cycle.

  12. Mesoporous silicas synthesis and application for lignin peroxidase immobilization by covalent binding method.

    Science.gov (United States)

    Hu, Zunfang; Xu, Longqian; Wen, Xianghua

    2013-01-01

    Immobilization of enzymes on mesoporous silicas (MS) allows for good reusability. MS with two-dimensional hexagonal pores in diameter up to 14.13 nm were synthesized using Pluronic P123 as template and 1,3,5-triisopropylbenzene as a swelling agent in acetate buffer. The surface of MS was modified by the silanization reagents 3-aminopropyltriethoxysilane. Lignin peroxidase (LiP) was successfully immobilized on the modified MS through covalent binding method by four agents: glutaraldehyde, 1,4-phenylene diisothiocyanate, cyanotic chloride and water-soluble carbodiimide. Results showed that cyanotic chloride provided the best performance for LIP immobilization. The loaded protein concentration was 12.15 mg/g and the immobilized LiP activity was 812.9 U/L. Immobilized LiP had better pH stability. Acid Orange II was used to examine the reusability of immobilized LiP, showing more than 50% of the dye was decolorized at the fifth cycle.

  13. Production and Characterization of Biodiesel Using Nonedible Castor Oil by Immobilized Lipase from Bacillus aerius

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Narwal

    2015-01-01

    Full Text Available A novel thermotolerant lipase from Bacillus aerius was immobilized on inexpensive silica gel matrix. The immobilized lipase was used for the synthesis of biodiesel using castor oil as a substrate in a solvent free system at 55°C under shaking in a chemical reactor. Several crucial parameters affecting biodiesel yield such as incubation time, temperature, substrate molar ratio, and amount of lipase were optimized. Under the optimized conditions, the highest biodiesel yield was up to 78.13%. The characterization of synthesized biodiesel was done through FTIR spectroscopy, 1H NMR spectra, and gas chromatography.

  14. Production and characterization of biodiesel using nonedible castor oil by immobilized lipase from Bacillus aerius.

    Science.gov (United States)

    Narwal, Sunil Kumar; Saun, Nitin Kumar; Dogra, Priyanka; Chauhan, Ghanshyam; Gupta, Reena

    2015-01-01

    A novel thermotolerant lipase from Bacillus aerius was immobilized on inexpensive silica gel matrix. The immobilized lipase was used for the synthesis of biodiesel using castor oil as a substrate in a solvent free system at 55°C under shaking in a chemical reactor. Several crucial parameters affecting biodiesel yield such as incubation time, temperature, substrate molar ratio, and amount of lipase were optimized. Under the optimized conditions, the highest biodiesel yield was up to 78.13%. The characterization of synthesized biodiesel was done through FTIR spectroscopy, (1)H NMR spectra, and gas chromatography.

  15. Immobilization strategy for enhancing sensitivity of immunosensors: L-Asparagine-AuNPs as a promising alternative of EDC-NHS activated citrate-AuNPs for antibody immobilization.

    Science.gov (United States)

    Raghav, Ragini; Srivastava, Sudha

    2016-04-15

    This paper addresses the question - Is EDC-NHS activated gold nanoparticles modified electrode surface the best available option for antibody immobilization for immunosensor fabrication? Is there any other alternative covalent immobilization strategy for orthogonal orientation of antibody, ensuring enhanced sensitivity of immunosensors? Does EDC-NHS activation of carboxyl functionalized nanoparticles surface really leads to orthogonal or directed immobilization of antibody? Gold nanoparticles synthesized using L-Asparagine as reducing and stabilization agent were employed for orthogonal immobilization of antibody for immunosensor fabrication. Anti-CA125 antibody was used as a model system for immunosensor fabrication. A comparative evaluation of immunosensors fabricated using L-Asparagine stabilized gold nanoparticles and citrate stabilized gold nanoparticles via different immobilization strategies/chemistries was done. The three strategies involved immobilization of Anti-CA125 antibody - (1) after EDC-NHS activation of citrate stabilized gold nanoparticles, (2) directly onto citrate stabilized gold nanoparticles and (3) directly onto L-Asparagine stabilized gold nanoparticles modified electrode surfaces. Comparative evaluation of Impedimetric response characteristics showed 2.5 times increase in sensitivity (349.36 Ω/(IU/mL)/cm(2)) in case of third strategy as compared to first (147.53 Ω/(IU/mL)/cm(2)) and twice that of second strategy (166.24 Ω/(IU/mL)/cm(2)). Additionally, an extended dynamic range of 0-750 IU/mL was observed while for others it was up to 500 IU/mL. Amino acid coated gold nanoparticles ensured orthogonal immobilization, lesser randomization, with 88% of active antibody available for antigen binding as opposed to other two strategies with less than 30% active antibody.

  16. Efficiency of aluminum-pillared montmorillonite on the removal of cesium and copper from aqueous solutions.

    Science.gov (United States)

    Karamanis, D; Assimakopoulos, P A

    2007-05-01

    Aluminum-pillared-layered montmorillonites (PILMs) were tested for their potential application in the removal of copper or cesium from aqueous solutions. By varying the initial conditions, several PILMs were prepared and characterized by means of X-ray fluorescence (XRF), proton induced gamma-ray emission (PIGE), X-ray diffraction (XRD) and sorption isotherms. Uptake of metals was studied by means of XRF spectrometry for copper sorption or gamma-ray spectrometry for cesium, using 137Cs as radiotracer. The sorption kinetics and capacity of PILMs were determined in relation to the effects of factors such as the initial metal concentration, initial pH of the solution and the presence of competitive cations. Kinetic studies showed that an equilibrium time of few minutes was needed for the adsorption of metal ions on PILMs. A pseudo-first-order equation was used to describe the sorption process for either copper or cesium. The most effective pH range for the removal of copper and cesium was found to be 4.0-6.0 and 3.0-8.0, respectively. Cesium sorption isotherms were best represented by a two-site Langmuir model while copper isotherms followed the Freundlich or the two-site Langmuir model. Cesium sorption experiments with inorganic or organic competitive cations as blocking agents revealed that the high selective sites of PILMs for cesium sorption (1-2% of total) are surface and edge sites in addition to interlayer exchange sites. In copper sorption, the two sites were determined as interlayer sites of PILMs after restoring their cation exchange capacity and sites associated with the pillar oxides.

  17. Chromatic instabilities in cesium-doped tungsten bronze nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Kenji, E-mail: kenji-adachi@ni.smm.co.jp; Ota, Yosuke; Tanaka, Hiroyuki; Okada, Mika; Oshimura, Nobumitsu; Tofuku, Atsushi [Ichikawa Research Laboratories, Sumitomo Metal Mining Co., Ltd., Ichikawa 272-8588 (Japan)

    2013-11-21

    Nanoparticles of alkali-doped tungsten bronzes are an excellent near-infrared shielding material, but exhibit slight chromatic instabilities typically upon applications of strong ultra-violet light or heating in humid environment, which acts detrimentally to long-life commercial applications. Origin of the chromatic instabilities in cesium-doped tungsten bronze has been investigated, and it has been found that the coloration and bleaching processes comprised electronic exchanges which accelerate or depress the polaron excitation and the localized surface plasmon resonance. Coloration on UV illumination is evidenced by electron diffraction as due to the formation of H{sub x}WO{sub 3}, which is considered to take place in the surface Cs-deficient WO{sub 3} region via the double charge injection mechanism. On the other hand, bleaching on heating in air and in humid environment is shown to accompany the extraction of Cs and electrons from Cs{sub 0.33}WO{sub 3} by X-ray photoelectron spectroscopy and X-ray diffraction analysis and is concluded to be an oxidation of Cs{sub 0.33}WO{sub 3} on the particle surface.

  18. The crystal structures of potassium and cesium trivanadates

    Science.gov (United States)

    Evans, H.T.; Block, S.

    1966-01-01

    Potassium and cesium trivanadates are monoclinic and isomorphous, space group P21/m, with the following dimensions (Z = 2): KV3O8, a = 7.640 A, b = 8.380 A, c = 4.979 A, ??= 96?? 57???; CsV3O8, a = 8.176 A, b = 8.519 A, c = 4.988 A, ?? = 95?? 32???. The crystal structure of KV3O8 has been determined from hk0, 0kl, and h0l Weissenberg data with an R factor of 0.15. The structure of CsV3O8 has been refined with 1273 hkl Weissenberg data to an R factor of 0.089. The structures consist of corrugated sheets based on a linkage of distorted VO6, octahedra. Two of the vanadium atoms lie in double, square-pyramid groups V2O8, which are linked through opposite basal corners into chains along the b axis. The chains are joined laterally along the c axis into sheets by the third vanadium atom in VO groups, also forming part of a square-pyramid coordination. Various aspects of these structures are compared with other known oxovanadate structures.

  19. Photoionization spectroscopy of excited states of cold cesium dimers

    CERN Document Server

    Bouloufa, Nadia; Viteau, Matthieu; Chotia, Amodsen; Fioretti, Andrea; Gabbanini, Carlo; Allegrini, Maria; Aymar, Mireille; Comparat, Daniel; Dulieu, Olivier; Pillet, Pierre

    2010-01-01

    Photoionization spectroscopy of cold cesium dimers obtained by photoassociation of cold atoms in a magneto-optical trap is reported here. In particular, we report on the observation and on the spectroscopic analysis of all the excited states that have actually been used for efficient detection of cold molecules stabilized in the triplet a^3Sigma_u^+ ground state. They are: the (1)^3Sigma_g^+ state connected to the 6s+6p asymptote, the (2)^3Sigma_g^+ and (2)^3Pi_g states connected to the 6s+5d asymptote and finally the (3)^3Sigma_g^+ state connected to the 6s + 7s asymptote. The detection through these states spans a wide range of laser energies, from 8000 to 16500 cm-1, obtained with different laser dyes and techniques. Information on the initial distribution of cold molecules among the different vibrational levels of the a^3Sigma_u^+ ground state is also provided. This spectroscopic knowledge is important when conceiving schemes for quantum manipulation, population transfer and optical detection of cold cesi...

  20. Ion exchange performance of commercial crystalline silicotitanates for cesium removal

    Energy Technology Data Exchange (ETDEWEB)

    Braun, R.; Dangieri, T.J.; Fennelly, D.J. [and others

    1996-03-01

    A new class of inorganic ion exchangers called crystalline silicotitanates (CST), invented by researchers at Sandia National Laboratories and Texas A&M University, has been commercialized in a joint Sandia-UOP effort. The original developmental materials exhibited high selectivity for the ion exchange of cesium, strontium, and several other radionuclides from highly alkaline solutions containing molar concentrations of Na{sup +}. The materials also showed excellent chemical and radiation stability. Together, the high selectivity and stability of the CSTs made them excellent candidates for treatment of solutions such as the Hanford tank supernates and other DOE radwastes. Sandia National Laboratories and UOP have teamed under a Cooperative Research and Development Agreement (CRADA) to develop CSTs in the powdered form and in an engineered form suitable for column ion exchange use. A continuous-flow, column ion exchange process is expected to be used to remove Cs and other radionuclides from the Hanford supernatant. The powder material invented by the Sandia and Texas A&M team consists of submicron-size particles. It is not designed for column ion exchange but may be used in other applications.

  1. Chromatic instabilities in cesium-doped tungsten bronze nanoparticles

    Science.gov (United States)

    Adachi, Kenji; Ota, Yosuke; Tanaka, Hiroyuki; Okada, Mika; Oshimura, Nobumitsu; Tofuku, Atsushi

    2013-11-01

    Nanoparticles of alkali-doped tungsten bronzes are an excellent near-infrared shielding material, but exhibit slight chromatic instabilities typically upon applications of strong ultra-violet light or heating in humid environment, which acts detrimentally to long-life commercial applications. Origin of the chromatic instabilities in cesium-doped tungsten bronze has been investigated, and it has been found that the coloration and bleaching processes comprised electronic exchanges which accelerate or depress the polaron excitation and the localized surface plasmon resonance. Coloration on UV illumination is evidenced by electron diffraction as due to the formation of HxWO3, which is considered to take place in the surface Cs-deficient WO3 region via the double charge injection mechanism. On the other hand, bleaching on heating in air and in humid environment is shown to accompany the extraction of Cs and electrons from Cs0.33WO3 by X-ray photoelectron spectroscopy and X-ray diffraction analysis and is concluded to be an oxidation of Cs0.33WO3 on the particle surface.

  2. Hanford Isotope Project strategic business analysis Cesium-137 (Cs-137)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    The purpose of this business analysis is to address the beneficial reuse of Cesium 137 (Cs-137) in order to utilize a valuable national asset and possibly save millions of tax dollars. Food irradiation is the front runner application along with other uses. This business analysis supports the objectives of the Department of Energy National Isotope Strategy distributed in August 1994 which describes the DOE plans for the production and distribution of isotope products and services. As part of the Department`s mission as stated in that document. ``The Department of Energy will also continue to produce and distribute other radioisotopes and enriched stable isotopes for medical diagnostics and therapeutics, industrial, agricultural, and other useful applications on a businesslike basis. This is consistent with the goals and objectives of the National Performance Review. The Department will endeavor to look at opportunities for private sector to co-fund or invest in new ventures. Also, the Department will seek to divest from ventures that can more profitably or reliably be operated by the private sector.``

  3. Study on immobilization of lipase onto magnetic microspheres with epoxy groups

    Science.gov (United States)

    Lei, Lin; Bai, Yongxiao; Li, Yanfeng; Yi, Liuxiang; Yang, Yong; Xia, Chungu

    2009-02-01

    Magnetic microspheres were synthesized by the suspension polymerization of glycidyl methacrylate (GMA), methacrylic acid (MAA) and divinyl benzene (DVB) in the presence of oleic acid-coated Fe 3O 4 nanoparticles. Triacylglycerol lipase from porcine pancreas was covalently immobilized on the magnetic microspheres via the active epoxy groups with the activity yield up to 63% (±2.3%) and enzyme loading of 39 (±0.5) mg/g supports. The resulting immobilized lipase had higher optimum temperature compared with those of free lipase and exhibited better thermal, broader pH stability and excellent reusability. Furthermore, the catalyzed capability of immobilized lipase was also investigated by catalyzing synthesis of hexyl acetate and the esterification conversion rate reached to 83% (±2.5%) after 12 h in nonaqueous solvent.

  4. Effective immobilization of DNA for development of polypyrrole nanowires based biosensor

    Science.gov (United States)

    Tran, Thi Luyen; Chu, Thi Xuan; Huynh, Dang Chinh; Pham, Duc Thanh; Luu, Thi Hoai Thuong; Mai, Anh Tuan

    2014-09-01

    This paper reports an easy technique for immobilization of the DNA to the conducting polymer polypyrrole nanowires (PPy NWs). The nanowires were electrochemically synthesized on the surface of working electrode in the presence of gelatin as a soft mold. The structure of obtained PPy NWs was investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and Surface Enhanced Raman Spectroscopy (SERS). The DNA strands were directly immobilized on the PPy NWs. The amino groups at the up-end of the PPy nanowires facilitate the linkage with the phosphate groups of the probe DNA. The DNA immobilization and hybridization were characterized by Electrochemical Impedance Spectroscopy (EIS). The initial results show that the sensor responses to 10 pM of DNA sequence in the solution.

  5. Removal of cesium from simulated liquid waste with countercurrent two-stage adsorption followed by microfiltration

    Energy Technology Data Exchange (ETDEWEB)

    Han, Fei; Zhang, Guang-Hui [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China); Gu, Ping, E-mail: guping@tju.edu.cn [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The adsorption isotherm of cesium by copper ferrocyanide followed a Freundlich model. Black-Right-Pointing-Pointer Decontamination factor of cesium was higher in lab-scale test than that in jar test. Black-Right-Pointing-Pointer A countercurrent two-stage adsorption-microfiltration process was achieved. Black-Right-Pointing-Pointer Cesium concentration in the effluent could be calculated. Black-Right-Pointing-Pointer It is a new cesium removal process with a higher decontamination factor. - Abstract: Copper ferrocyanide (CuFC) was used as an adsorbent to remove cesium. Jar test results showed that the adsorption capacity of CuFC was better than that of potassium zinc hexacyanoferrate. Lab-scale tests were performed by an adsorption-microfiltration process, and the mean decontamination factor (DF) was 463 when the initial cesium concentration was 101.3 {mu}g/L, the dosage of CuFC was 40 mg/L and the adsorption time was 20 min. The cesium concentration in the effluent continuously decreased with the operation time, which indicated that the used adsorbent retained its adsorption capacity. To use this capacity, experiments on a countercurrent two-stage adsorption (CTA)-microfiltration (MF) process were carried out with CuFC adsorption combined with membrane separation. A calculation method for determining the cesium concentration in the effluent was given, and batch tests in a pressure cup were performed to verify the calculated method. The results showed that the experimental values fitted well with the calculated values in the CTA-MF process. The mean DF was 1123 when the dilution factor was 0.4, the initial cesium concentration was 98.75 {mu}g/L and the dosage of CuFC and adsorption time were the same as those used in the lab-scale test. The DF obtained by CTA-MF process was more than three times higher than the single-stage adsorption in the jar test.

  6. Potential of Calendula alata for phytoremediation of stable cesium and lead from solutions.

    Science.gov (United States)

    Borghei, Mehdi; Arjmandi, Reza; Moogouei, Roxana

    2011-10-01

    Calendula alata plants were tested for their potential to remove stable cesium and lead from solutions in a 15-day period. The plants were grown hydroponically and placed in solutions containing CsCl and Pb(C₂H₃O₂)₂ at different concentrations (0.6, 2 and 5 mg l⁻¹). When plants were incubated in CsCl solutions 46.84 ± 2.12%, 41.35 ± 1.59%, and 52.06 ± 1.02% cesium was found to be remediated after 15 days. Moreover, more than 99% lead was removed from the Pb(C₂H₃O₂)₂ solution in all three concentrations after 15 days during the same period. When both CsCl and Pb(C₂H₃O₂)₂ were supplemented together in the solution, 9.92 ± 1.22%, 45.56 ± 3.52%, and 46.16 ± 1.48% cesium and 95.30 ± 0.72%, 96.64 ± 0.30%, and 99.02 ± 0.04% lead were removed after 15 days. The present study suggests that hydroponically grown C. alata could be used as a potential candidate plant for phytoremediation of cesium and lead from solutions; however, plants were found to be more efficient for the remediation of lead than cesium.

  7. Preparation of Modified Kaolin Filler with Cesium and Its Application in Security Paper

    Directory of Open Access Journals (Sweden)

    Houssni El-Saied

    2013-01-01

    Full Text Available In this study, cesium was added intentionally during paper manufacture for protecting the papers against forgery and counterfeiting by sorbing cesium ions (Cs+ on kaolin, used as special filler in papermaking. The sorption of cesium from aqueous solution by kaolin was studied as a function of pH, shaking time, cesium initial concentration, and mass of kaolin using batch technique. The results showed that a solution containing 10 mg/L Cs+ and 250 mg of kaolin at pH 6 can be used to modify the kaolin. Paper handsheets were prepared containing various percentages of the modified kaolin. The mechanical and optical properties of paper handsheets were studied. The prepared paper handsheets were irradiated by gamma irradiation using different doses. Fourier transform infrared (FTIR spectroscopy was used to study the effect of kaolin modification by cesium and gamma irradiation on paper handsheets properties. The results indicated that modified kaolin enhanced the mechanical and optical properties of paper handsheets. Electron spin resonance (ESR spectroscopy and laser-induced breakdown spectroscopy (LIBS were also used. They provided rapid, sensitive and nondestructive techniques in differentiating between different questioned documents. This study presents a new concept in manufacturing security papers and anticounterfeiting applications.

  8. Production of Biodiesel Using Immobilized Lipase and the Characterization of Different Co-Immobilizing Agents and Immobilization Methods

    Directory of Open Access Journals (Sweden)

    Kang Zhao

    2016-08-01

    Full Text Available Lipase from Candida sp. 99–125 is widely employed to catalyzed transesterification and can be used for biodiesel production. In this study, the lipase was immobilized by combined adsorption and entrapment to catalyze biodiesel production from waste cooking oil (WCO via transesterification, and investigating co-immobilizing agents as additives according to the enzyme activity. The addition of the mixed co-immobilizing agents has positive effects on the activities of the immobilized lipase. Three different immobilizing methods were compared by the conversion ratio of biodiesel and structured by Atom Force Microscopy (AFM and Scanning Electron Microscopy (SEM, respectively. It was found that entrapment followed by adsorption was the best method. The effect of the co-immobilizing agent amount, lipase dosage, water content, and reuse ability of the immobilized lipase was investigated. By comparison with previous research, this immobilized lipase showed good reuse ability: the conversion ratio excesses 70% after 10 subsequent reactions, in particular, was better than Novozym435 and TLIM on waste cooking oil for one unit of lipase.

  9. Immobilization of Co{sup 2+} and Cs{sup +} in zeolites by thermal treatment and by combustion; Inmovilizacion de Co{sup 2+} y Cs{sup +} en zeolitas por tratamiento termico y por combustion

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez T, R.; Bulbulian G, S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: rosarodtre@yahoo.com

    2005-07-01

    The radioactive waste, either those that take place in the {sup 235}U fission or those that are used in the radiochemical laboratories, are dangerous for the human being and for the one environment. The liquid radioactive wastes are of those that present bigger problem. It has intended to retain by the ion exchange method the radioactive ions of the liquids using, for example, zeolites. In this work so much synthetic zeolites was used (A and X) like a natural zeolite (clinoptilolite). Its were put in contact with cobalt or cesium solutions to simulate radioactive solutions. A part of the zeolite cations were exchanged with cobalt or cesium cations, eliminating them by this way of the solution. However, in extreme conditions these cations can be leached of the solids. To immobilize the cobalt or cesium cations in the zeolites net its are usually carried out thermal treatments to such temperatures that the structure is destroyed and that the contaminating ions are trapped in a solid often vitreous. The exchanged zeolites with cobalt or cesium, on one hand, its were thermally treated to different temperatures during three hours and by the other one, according to the treatment method by combustion, to different temperatures during five minutes in presence of urea, later its were put in contact with a solution of NaCl to measure the leaching of the interest cations. These solutions were analyzed by neutron activation. In general it was found that as the treatment temperature increases (in both methods) the so much immobility of the cesium like of the cobalt it increases. The grade of crystallinity of the samples before and after the treatments it was determined by X-ray diffraction. (Author)

  10. Synthesis and Heavy Metal Immobilization Behaviors of Fly Ash based Gepolymer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunsheng; SUN Wei; SHE Wei; SUN Guowei

    2009-01-01

    Two aspects of studies were carried out:1)synthesis of geopolymer by using fly ash and metakaolin;2)Immobilization behaviors of fly ash based geopolymer in a presence of Pb and Cu ions.As for the synthesis of fly ash based geopolymer,4 different fly ash content(10%,30%, 50%,70%)and 3 types of curing regimes(standard curing,steam curing and autoclave curing)were investigated to obtain the optimum synthesis condition based on the compressive and flexural strength.The experimental results show that geopolymer,containing 30%fly ash and synthesized at steam curing(80℃ for 8 h),exhibits higher mechanical strengths.The compressive and flexural strengths of fly ash based geopolymer reach 32.2 Mpa and 7.15 Mpa,respectively.Additionally,In-frared (IR) and X-ray diffraction(XRD)techniques were used to characterize the microstructure of the fly ash geopolymer.IR spectra shows that the absorptive band at 1086 cm ~(-1) shifts to lower wave number around 1033 cm ~(-1) ,and the 6-coordinated Al transforms into 4-coordination during the syn-thesis of fly ash based geopolymer.The resulting geopolymeric products were X-ray amorphous ma-terials.As for immobilization of heavy metals,the leaching tests were employed to investigate the immobilization behaviors of the fly ash based geopolymer synthesized under the above optimum condition.The leaching tests showed that fly ash based geopolymer can effectively immobilize Cu and Pb heavy metal ions,and the immobilization efficiency reached 90% greater when heavy metals were incorporated in the fly ash geopolymer in the range of 0.1% to 0.3%.The Pb exhibits better immobilization efficiency than the Cu,especially in the case of large dosages of heavy metals.

  11. Immobilization of bovine catalase onto magnetic nanoparticles.

    Science.gov (United States)

    Doğaç, Yasemin İspirli; Teke, Mustafa

    2013-01-01

    The scope of this study is to achieve carrier-bound immobilization of catalase onto magnetic particles (Fe₃O₄ and Fe₂O₃NiO₂ · H₂O) to specify the optimum conditions of immobilization. Removal of H2O2 and the properties of immobilized sets were also investigated. To that end, adsorption and then cross-linking methods onto magnetic particles were performed. The optimum immobilization conditions were found for catalase: immobilization time (15 min for Fe₃O₄; 10 min for Fe2O₃NiO₂ · H₂O), the initial enzyme concentration (1 mg/mL), amount of magnetic particles (25 mg), and glutaraldehyde concentration (3%). The activity reaction conditions (optimum temperature, optimum pH, pH stability, thermal stability, operational stability, and reusability) were characterized. Also kinetic parameters were calculated by Lineweaver-Burk plots. The optimum pH values were found to be 7.0, 7.0, and 8.0 for free enzyme, Fe₃O₄-immobilized catalases, and Fe₂O₃NiO₂ · H₂O-immobilized catalases, respectively. All immobilized catalase systems displayed the optimum temperature between 25 and 35°C. Reusability studies showed that Fe₃O₄-immobilized catalase can be used 11 times with 50% loss in original activity, while Fe2O₃NiO₂ · H₂O-immobilized catalase lost 67% of activity after the same number of uses. Furthermore, immobilized catalase systems exhibited improved thermal and pH stability. The results transparently indicate that it is possible to have binding between enzyme and magnetic nanoparticles.

  12. Application of ring-opening metathesis polymerization in study of polymer molecular weight-mediated catalytic properties of immobilized lipase

    Institute of Scientific and Technical Information of China (English)

    DU Chuang; ZHANG Guo; WANG Zhi; LI Lei; TANG Jun; WANG Lei

    2009-01-01

    Recently, significant efforts have been devoted into the study of the effect of hydrophobic supports on the catalytic properties of immobilized lipases. It seems that immobilization lipases on hydrophobic supports is a simple and efficient method to improve the catalytic activity of lipases. In this study, the hydrophobic poly(N-propyl-norbornene-exo-2,3-dicarboximide)s with well-controlled molecular weight were synthesized by the living ring-opening metathesis polymerization, and the lipases from Pseudo-monas sp. were then immobilized on these hydrophobic polymer supports through the physical ad-sorption. The immobilized lipases exhibited higher activity and enantioselectivity for the transesterifi-cation of 2-octanol than those of free lipases. Furthermore, we investigated the polymer molecular weight-mediated catalytic properties of immobilized lipases. It was found that the catalytic activity and E value of the immobilized lipases increased with the increase of the polymer molecular weight. At the polymeric molecular weight of about 40kDa, the highest E value (58 at 54.2% of conversion, enanti-omeric excess = 99%) was reached. After the molecular weight of polymers getting higher than 40 kDa, catalytic activity end E value of the immobilized lipase decreased.

  13. Polyethyleneimine-modified superparamagnetic Fe{sub 3}O{sub 4} nanoparticles for lipase immobilization: Characterization and application

    Energy Technology Data Exchange (ETDEWEB)

    Khoobi, Mehdi; Motevalizadeh, Seyed Farshad [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 1417614411 (Iran, Islamic Republic of); Asadgol, Zahra [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411 (Iran, Islamic Republic of); Forootanfar, Hamid [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman (Iran, Islamic Republic of); Shafiee, Abbas, E-mail: ashafiee@ams.ac.ir [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 1417614411 (Iran, Islamic Republic of); Faramarzi, Mohammad Ali, E-mail: faramarz@tums.ac.ir [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 1417614411 (Iran, Islamic Republic of)

    2015-01-15

    Magnetically separable nanospheres consisting of polyethyleneimine (PEI) and succinated PEI grafted on silica coated magnetite (Fe{sub 3}O{sub 4}) were prepared and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, vibrating sample magnetometer, scanning electron microscopy and transmission electron microscopy. The prepared magnetic nanoparticles were then applied for physical adsorption or covalent attachment of Thermomyces lanuginosa lipase (TLL) via glutaraldehyde or hexamethylene diisocyanate. The reusability, storage, pH and thermal stabilities of the immobilized enzymes compared to that of free lipase were examined. The obtained results showed that the immobilized lipase on MNPs@PEI-GLU was the best biocatalyst which retained 80% of its initial activity after 12 cycles of application. The immobilized lipase on the selected support (MNPs@PEI-GLU) was also applied for the synthesis of ethyl valerate. Following 24 h incubation of the immobilized lipase on the selected support in n-hexane and solvent free media, the esterification percentages were 72.9% and 28.9%, respectively. - Graphical abstract: A schematic of the preparation of PEI- and succinated PEI-grafted Fe{sub 3}O{sub 4} MNPs (MNPs@PEI) and the immobilization of lipase by covalent bonding and adsorption. - Highlights: • Functionalized polyethylenimine-grafted magnetic nanoparticles were synthesized. • The prepared supports were fully characterized by various analysis methods. • Lipase was immobilized on the nanostructures by adsorption and covalent attachment. • Immobilized lipase produced ethyl valerate in solvent free medium.

  14. Immobilization of glucoamylase on triazine-functionalized Fe3O4/graphene oxide nanocomposite: Improved stability and reusability.

    Science.gov (United States)

    Amirbandeh, Mahkameh; Taheri-Kafrani, Asghar

    2016-12-01

    Immobilization of an enzyme can enhance its catalytic activity, depending on the properties of the enzyme and the matrix. Graphene oxide is a nontoxic material and selective modulator for enzyme activity and is also a thermostable molecule that is important in large-scale nanostructure sheet applications. Herein, we have successfully developed a strategy for preparing a nanocomposite for enzyme immobilization model with high loading capacity. Nanostructures of hybrid graphene oxide-Fe3O4-cyanuric chloride (GO/MNP-CC) have adjustable surface chemistry that is an excellent candidate for covalent immobilization of enzymes. The morphology, structure and properties of GO/MNP-CC nanocomposite were investigated through different analytical tools. Glucoamylase, an important enzyme in industrial food products, was immobilized on GO/MNP-CC and exhibited excellent catalytic activity at pH 6.5 and 60°C. The results of this study indicated that the catalytic activity, reusability and stability of immobilized enzyme have been obviously improved compared to the free enzyme. The apparent Km and νmax for free and immobilized glucoamylase were also determined. These properties make them a good candidate to improve the practicality and further the development of the capacity enzyme attachment. Thus, the synthesized matrix has the potential for practical applications in other and binary enzyme immobilization and would have a wide prospect for their applications in bio-industry and biosensing.

  15. Collagen-poly(dialdehyde) guar gum based porous 3D scaffolds immobilized with growth factor for tissue engineering applications.

    Science.gov (United States)

    Ragothaman, Murali; Palanisamy, Thanikaivelan; Kalirajan, Cheirmadurai

    2014-12-19

    Here we report the preparation of collagen-poly(dialdehyde) guar gum based hybrid functionalized scaffolds covalently immobilized with platelet derived growth factor - BB for tissue engineering applications. Poly(dialdehyde) guar gum was synthesized from selective oxidation of guar gum using sodium periodate. The synthesized poly(dialdehyde) guar gum not only promotes crosslinking of collagen but also immobilizes the platelet derived growth factor through imine bonds. The covalent crosslinking formed in collagen improves thermal, swelling and biodegradation properties of the hybrid scaffolds. The prepared hybrid scaffolds show 3D interconnected honeycomb porous structure when viewed under a microscope. The release of immobilized platelet derived growth factor was seen up to 13th day of incubation thereby proving its sustained delivery. The developed hybrid scaffold leads to a quantum increase in NIH 3T3 fibroblast cell density and proliferation thereby demonstrating its potential for tissue engineering applications.

  16. Comparison of organic and inorganic ion exchange materials for removal of cesium and strontium from tank waste

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-10-01

    This work is part of an ESP task to develop high-capacity, selective, solid extractants for cesium, strontium, and technetium from nuclear wastes. Pacific Northwest National Laboratory (PNNL) staff are investigating novel ion exchangers for use in nuclear waste remediation (groundwater, high-level waste (HLW), and low-level waste (LLW)). Waste components targeted for remediation include cesium, strontium, and technetium.

  17. Technetium Immobilization Forms Literature Survey

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  18. Sympathetic cooling in a rubidium cesium mixture: Production of ultracold cesium atoms; Sympathetisches Kuehlen in einer Rubidium-Caesium-Mischung: Erzeugung ultrakalter Caesiumatome

    Energy Technology Data Exchange (ETDEWEB)

    Haas, M.

    2007-07-01

    This thesis presents experiments for the production of ultracold rubidium cesium mixture in a magnetic trap. The long-termed aim of the experiment is the study of the interaction of few cesium atoms with a Bose-Einstein condensate of rubidium atoms. Especially by controlled variation of the cesium atom number the transition in the description of the interaction by concepts of the one-particle physics to the description by concepts of the many-particle physics shall be studied. The rubidium atoms are trapped in a magneto-optical trap (MOT) and from there reloaded into a magnetic trap. In this the rubidium atoms are stored in the state vertical stroke f=2,m{sub f}=2 right angle of the electronic ground state and evaporatively cooled by means of microwave-induced transitions into the state vertical stroke f=1,m{sub f}=1] (microwave cooling). The cesium atoms are also trppaed in a MOT and into the same magnetic trap reloaded, in which they are stored in the state vertical stroke f=4,m{sub f}=4 right angle of the electronic ground state together with rubidium. Because of the different hyperfine splitting only rubidium is evaporatively cooled, while cesium is cooled jointly sympathetically - i.e. by theramal contact via elastic collisions with rubidium atoms. The first two chapters contain a description of interatomic interactions in ultracold gases as well as a short summary of theoretical concepts in the description of Bose-Einstein condensates. The chapters 3 and 4 contain a short presentation of the methods applied in the experiment for the production of ultracold gases as well as the experimental arrangement; especially in the framework of this thesis a new coil system has been designed, which offers in view of future experiments additionally optical access for an optical trap. Additionally the fourth chapter contains an extensive description of the experimental cycle, which is applied in order to store rubidium and cesium atoms together into the magnetic trap. The

  19. Immobilization of Ion Exchange radioactive resins of the TRIGA Mark III Nuclear Reactor; Inmovilizacion de resinas de intercambio ionico radiactivas del reactor nuclear TRIGA Mark III

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Martinez, H

    1999-07-01

    In the last decades many countries in the world have taken interest in the use, availability, and final disposal of dangerous wastes in the environment, within these, those dangerous wastes that contain radioactive material. That is why studies have been made on materials used as immobilization agent of radioactive waste that may guarantee its storage for long periods of time under drastic conditions of humidity, temperature change and biodegradation. In mexico, the development of different applications of radioactive material in the industry, medicine and investigation, have generated radioactive waste, sealed and open sources, whose require a special technological development for its management and final disposal. The present work has as a finality to develop the process and define the agglutinating material, bitumen, cement and polyester resin that permits immobilization of resins of Ionic Exchange contaminated by Barium 153, Cesium 137, Europium 152, Cobalt 60 and Manganese 54 generated from the nuclear reactor TRIGA Mark III. Ionic interchange contaminated resin must be immobilized and is analysed under different established tests by the Mexican Official Standard NOM-019-NUCL-1995 {sup L}ow level radioactive wastes package requirements for its near-surface final disposal. Immobilization of ionic interchange contaminated resins must count with the International Standards applicable in this process; in these standards, the following test must be taken in prototype examples: Free-standing water, leachability, compressive strength, biodegradation, radiation stability, thermal stability and burning rate. (Author)

  20. Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

    OpenAIRE

    Enas N. Danial; Amal H. Hamza; Rasha H. Mahmoud

    2015-01-01

    This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease...

  1. Silica-Immobilized Enzyme Reactors (Postprint)

    Science.gov (United States)

    2007-09-01

    Non-solubilized UDPGT from rat liver microsomes was covalently immobilized to a func- tionalized silica support by Schiff base chemistry and a number...activity within a day. GADPH isolated from rabbit was covalently immobilized to a wide-pore silica support by glutaraldehyde activation and Schiff - base chemistry

  2. Engineering aspects of nitrification with immobilized cells.

    NARCIS (Netherlands)

    Hunik, J.H.

    1993-01-01

    Several aspects of a nitrification process with artificially immobilized cells in an airlift loop reactor have been investigated and are described in this thesis. In chapter 1 an overview of immobilization methods, suitable reactors, modelling, small-scaleapplications and scale-up strategy is given.

  3. Optimization of Adsorptive Immobilization of Alcohol Dehydrogenases

    NARCIS (Netherlands)

    Trivedi, Archana; Heinemann, Matthias; Spiess, Antje C.; Daussmann, Thomas; Büchs, Jochen

    2005-01-01

    In this work, a systematic examination of various parameters of adsorptive immobilization of alcohol dehydrogenases (ADHs) on solid support is performed and the impact of these parameters on immobilization efficiency is studied. Depending on the source of the enzymes, these parameters differently in

  4. The effects of using Cesium-137 teletherapy sources as a radiological weapon (dirty bomb)

    CERN Document Server

    Liolios, Theodore

    2009-01-01

    While radioactive sources used in medical diagnosis do not pose a great security risk due to their low level of radioactivity, therapeutic sources are extremely radioactive and can presumably be used as a radiological weapon. Cobalt-60 and Cesium-137 sources are the most common ones used in radiotherapy with over 10,000 of such sources currently in use worldwide, especially in the developing world, which cannot afford modern accelerators. The present study uses computer simulations to investigate the effects of using Cesium-137 sources from teletherapy devices as a radiological weapon. Assuming a worst-case terrorist attack scenario, we estimate the ensuing cancer mortality, land contamination, evacuation area, as well as the relevant evacuation, decontamination, and health costs in the framework of the linear risk model. The results indicate that an attack with a Cesium-137 dirty bomb in a large metropolitan city (especially one that would involve several teletherapy sources) although would not cause any sta...

  5. Phosphate ceramic solidification and stabilization of cesium-containing crystalline silicotitanate resins.

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. A.

    1999-05-11

    This paper reports on the fabrication and testing of magnesium potassium phosphate (MKP)-bonded cesium-loaded crystalline silicotitanate (CST) resins. Typical waste loading of CST resins in the final waste forms was 50 wt.%. Physical and chemical characterization of the MKP materials has shown them to be physically, chemically, and mineralogically stable. Long-term durability studies (using the AN 16.1 standard test) showed a leachability index of {approx}18 for cesium in the phosphate matrix when exposed to deionized water under ambient and elevated temperatures. Leaching of cesium was somewhat higher than in glass waste forms as per PCT and MCC-1 tests. MKP-based final waste forms showed no significant weight changes after exposure to aqueous media for {approx}90 days, indicating the highly insoluble nature of the phosphate matrix. In addition, durability of the CST-MKP waste forms was further established by freeze-thaw cycling tests.

  6. Selection of chemotherapy for metastatic mammary cancer by effect on cesium-131 uptake.

    Science.gov (United States)

    Ferguson, D J; Harper, P V

    1977-09-01

    Cesium-131 was administered intravenously to 39 patients with superficial metastases of mammary carcinoma and the concentration in tumor was compared with that in normal tissue by application of a detector in vivo, before and after 1 to 5 days of chemotherapy with cyclophosphamide (CP), 5-fluorouracil (FU), or diethylstilbestrol. A change of the cesium concentration ratio (tumor/normal tissue) greater than 15% after brief treatment correctly predicted the therapeutic effect after 1 to 39 months on the tumors that were tested in 30 of 33 tests. No reliable correlation could be made in the remaining 21 tests in which the change of ratio was less than 15%. The concentration of cesium-131 in the skin, fat, and skeletal muscle of mice was not appreciably altered by treatment for 5 days with CP or FU.

  7. Method of Preparation for High-Purity Nanocrystalline Anhydrous Cesium Perrhenate

    Directory of Open Access Journals (Sweden)

    Katarzyna Leszczyńska-Sejda

    2017-03-01

    Full Text Available This paper is devoted to the preparation of high-purity anhydrous nanocrystalline cesium perrhenate, which is applied in catalyst preparation. It was found that anhydrous cesium perrhenate with a crystal size <45 nm can be obtained using cesium ion sorption and elution using aqueous solutions of perrhenic acid with subsequent crystallisation, purification, and drying. The following composition of the as-obtained product was reported: 34.7% Cs; 48.6% Re and <2 ppm Bi; <3 ppm Zn; <2 ppm As; <10 ppm Ni; < 3 ppm Mg; <5 ppm Cu; <5 ppm Mo; <5 ppm Pb; <10 ppm K; <2 ppm Na; <5 ppm Ca; <3 ppm Fe.

  8. Cesium removal from liquid acidic wastes with the primary focus on ammonium molybdophosphate as an ion exchanger: A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Miller, C.J.

    1995-03-01

    Many articles have been written concerning the selective removal of cesium from both acidic and alkaline defense wastes. The majority of the work performed for cesium removal from defense wastes involves alkaline feed solutions. Several different techniques for cesium removal from acidic solutions have been evaluated such as precipitation, solvent extraction, and ion exchange. The purpose of this paper is to briefly review various techniques for cesium removal from acidic solutions. The main focus of the review will be on ion exchange techniques, particularly those involving ammonium molybdophosphate as the exchanger. The pertinent literature sources are condensed into a single document for quick reference. The information contained in this document was used as an aid in determining techniques to evaluate cesium removal from the acidic Idaho Chemical Processing Plant waste matrices. 47 refs., 2 tabs.

  9. TiO₂ beads and TiO₂-chitosan beads for urease immobilization.

    Science.gov (United States)

    Ispirli Doğaç, Yasemin; Deveci, Ilyas; Teke, Mustafa; Mercimek, Bedrettin

    2014-09-01

    The aim of the present study is to synthesize TiO2 beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO2 beads. In the first method (A), urease enzyme was immobilized onto TiO2 beads by adsorption and then crosslinking. In the second method (B), TiO2 beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5mg/ml for A and 1.0mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60°C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70°C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30°C (A), 40°C (B) and 35°C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65°C. However, at this temperature free urease protected only 15% activity.

  10. Covalent Immobilization of Biotin on Magnetic Nanoparticles: Synthesis, Characterization, and Cytotoxicity Studies.

    Science.gov (United States)

    Islam, Md Rafiqul; Bach, Long Giang; Vo, Thanh-Sang; Lim, Kwon Taek

    2015-01-01

    A simple protocol for covalent immobilization of biotin onto the surface of Fe3O4 magnetic nanoparticles (MNPs) for improving the biocompatibility of original MNPs has been realized. MNPs were first prepared by co-precipitation method which was subsequently anchored with functionalized biotin. The as-synthesized MNPs were observed to be monocrystalline as evidenced from XRD and TEM images. The covalent grafting of biotin to MNPs was confirmed by FT-IR. The XPS analysis suggested the successful preparation of Biotin-f-MNPs. The as-synthesized Biotin-f-MNPs were found to be superparamagnetic character as recorded by SQUID. Cell viability studies revealed that the biocompatibility of MNPs was improved upon Biotin immobilization.

  11. Covalent Immobilization of Bacillus licheniformis γ-Glutamyl Transpeptidase on Aldehyde-Functionalized Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Meng-Chun Chi

    2013-02-01

    Full Text Available This work presents the synthesis and use of surface-modified iron oxide nanoparticles for the covalent immobilization of Bacillus licheniformis γ-glutamyl transpeptidase (BlGGT. Magnetic nanoparticles were prepared by an alkaline solution of divalent and trivalent iron ions, and they were subsequently treated with 3-aminopropyltriethoxysilane (APES to obtain the aminosilane-coated nanoparticles. The functional group on the particle surface and the amino group of BlGGT was then cross-linked using glutaraldehyde as the coupling reagent. The loading capacity of the prepared nanoparticles for BlGGT was 34.2 mg/g support, corresponding to 52.4% recovery of the initial activity. Monographs of transmission electron microscopy revealed that the synthesized nanoparticles had a mean diameter of 15.1 ± 3.7 nm, and the covalent cross-linking of the enzyme did not significantly change their particle size. Fourier transform infrared spectroscopy confirmed the immobilization of BlGGT on the magnetic nanoparticles. The chemical and kinetic behaviors of immobilized BlGGT are mostly consistent with those of the free enzyme. The immobilized enzyme could be recycled ten times with 36.2% retention of the initial activity and had a comparable stability respective to free enzyme during the storage period of 30 days. Collectively, the straightforward synthesis of aldehyde-functionalized nanoparticles and the efficiency of enzyme immobilization offer wide perspectives for the practical use of surface-bound BlGGT.

  12. Construction of an Immobilized Thermophilic Esterase on Epoxy Support for Poly(ε-caprolactone Synthesis

    Directory of Open Access Journals (Sweden)

    Hui Ren

    2016-06-01

    Full Text Available Developing an efficient immobilized enzyme is of great significance for improving the operational stability of enzymes in poly(ε-caprolactone synthesis. In this paper, a thermophilic esterase AFEST from the archaeon Archaeoglobus fulgidus was successfully immobilized on the epoxy support Sepabeads EC-EP via covalent attachment, and the immobilized enzyme was then employed as a biocatalyst for poly(ε-caprolactone synthesis. The enzyme loading and recovered activity of immobilized enzyme was measured to be 72 mg/g and 10.4 U/mg using p-nitrophenyl caprylate as the substrate at 80 °C, respectively. Through the optimization of reaction conditions (enzyme concentration, temperature, reaction time and medium, poly(ε-caprolactone was obtained with 100% monomer conversion and low number-average molecular weight (Mn < 1300 g/mol. Further, the immobilized enzyme exhibited excellent reusability, with monomer conversion values exceeding 75% during 15 batch reactions. Finally, poly(ε-caprolactone was enzymatically synthesized with an isolated yield of 75% and Mn value of 3005 g/mol in a gram-scale reaction.

  13. Stable and Simple Immobilization of Proteinase K Inside Glass Tubes and Microfluidic Channels.

    Science.gov (United States)

    Küchler, Andreas; Bleich, Julian N; Sebastian, Bernhard; Dittrich, Petra S; Walde, Peter

    2015-11-25

    Engyodontium album proteinase K (proK) is widely used for degrading proteinaceous impurities during the isolation of nucleic acids from biological samples, or in proteomics and prion research. Toward applications of proK in flow reactors, a simple method for the stable immobilization of proK inside glass micropipette tubes was developed. The immobilization of the enzyme was achieved by adsorption of a dendronized polymer-enzyme conjugate from aqueous solution. This conjugate was first synthesized from a polycationic dendronized polymer (denpol) and proK and consisted, on average, of 2000 denpol repeating units and 140 proK molecules, which were attached along the denpol chain via stable bis-aryl hydrazone bonds. Although the immobilization of proK inside the tube was based on nonspecific, noncovalent interactions only, the immobilized proK did not leak from the tube and remained active during prolonged storage at 4 °C and during continuous operation at 25 °C and pH = 7.0. The procedure developed was successfully applied for the immobilization of proK on a glass/PDMS (polydimethylsiloxane) microchip, which is a requirement for applications in the field of proK-based protein analysis with such type of microfluidic devices.

  14. Laccase Immobilized on Mesoporous Silica Materials and Its Corrosion Inhibition Performance in Circulating Cooling Water System

    Institute of Scientific and Technical Information of China (English)

    Liu Fang; Lü Yucui; Zhong Huiyun; Zhang Shuang; Fan Fengtao; Zhao Chaocheng

    2015-01-01

    Mesoporous SiO2 microspheres were synthesized using the sol-gel method and were characterized byTEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore di-ameter is 2.55 nm, while the speciifc surface area is 1 088.9 m2/g. Mesoporous SiO2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The im-mobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efifciency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibi-tion efifciency of free laccase (59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immo-bilized laccase could degrade diesel to inhibit corrosion.

  15. Preparation and characterization of magnetic levan particles as matrix for trypsin immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Maciel, J.C. [Programa de Pos-Graduacao em Ciencias Biologicas, Universidade Federal de Pernambuco, Cidade Universitaria, 50670-901 Recife, PE (Brazil); Andrad, P.L. [Programa de Pos-Graduacao em Ciencia de Materiais, Universidade Federal de Pernambuco, Cidade Universitaria, 50679-901 Recife, PE (Brazil); Neri, D.F.M., E-mail: davidfmneri@yahoo.com.br [Universidade Federal do Vale do Sao Francisco, 56304-205 Petrolina, PE (Brazil); Carvalho, L.B. [Departamento de Bioquimica, Universidade Federal de Pernambuco, Cidade Universitaria, 50679-901 Recife, PE (Brazil); Cardoso, C.A. [Departamento de Fisica, Universidade Federal de Sao Carlos, 13565-905 Sao Carlos, PE (Brazil); Calazans, G.M.T. [Departamento de Antibioticos, Universidade Federal de Pernambuco, Cidade Universitaria, 50670-901 Recife, PE (Brazil); Albino Aguiar, J. [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, 50679-901 Recife, PE (Brazil); Silva, M.P.C. [Departamento de Bioquimica, Universidade Federal de Pernambuco, Cidade Universitaria, 50679-901 Recife, PE (Brazil)

    2012-04-15

    Magnetic levan was synthesized by co-precipitating D-fructofuranosyl homopolysaccharide with a solution containing Fe{sup 2+} and Fe{sup 3+} in alkaline conditions at 100 Degree-Sign C. The magnetic levan particles were characterized by scanning electron microscopy (SEM), magnetization measurements, X-ray diffractometry (XRD) and infrared spectroscopy (IR). Afterwards, magnetic levan particles were functionalized by NaIO{sub 4} oxidation and used as matrices for trypsin covalent immobilization. Magnetite and magnetic levan particles were both heterogeneous in shape and levan-magnetite presented bigger sizes compared to magnetite according to SEM images. Magnetic levan particles exhibited a magnetization 10 times lower as compared to magnetite ones, probably, due to the coating layer. XRD diffractogram showed that magnetite is the dominant phase in the magnetic levan. Infrared spectroscopy showed characteristics absorption bands of levan and magnetite (O-H, C-O-C and Fe-O bonds). The immobilized trypsin derivative was reused 10 times and lost 16% of its initial specific activity only. Therefore, these magnetic levan particles can be proposed as an alternative matrices for enzyme immobilization. - Highlights: Black-Right-Pointing-Pointer The magnetic levan particles presented larger size variation than magnetite particles due to the changes produced by coating. Black-Right-Pointing-Pointer The utilization of magnetic levan particles showed to be efficacious for immobilization of enzymes as trypsin. Black-Right-Pointing-Pointer Magnetic particles can be planned as other matrix for immobilization of biomolecule in various division processes in biotechnology.

  16. Preparation of a pH-sensitive polyacrylate amphiphilic copolymer and its application in cellulase immobilization.

    Science.gov (United States)

    Liang, Wenjuan; Cao, Xuejun

    2012-07-01

    P(MDB), a pH-sensitive and reversible water-soluble copolymer, was synthesized with methacrylic acid (MAA), 2-(dimethylamino) ethyl methacrylate (DMAEMA), and butyl methacrylate (BMA) and used as carrier for cellulase. The copolymer is insoluble between pH 2.5 and 4.1, and soluble below pH 2.5 or above 4.1. Its recovery in aqueous solution was 97.2% by adjusting its isoelectric point (pI) to 3.1. Cellulase was covalently immobilized on P(MDB) with 1-ethyl-3-(3-dimethyllaminopropyl) carbodiimide. Under optimized conditions, the activity yield of immobilized cellulase was 63.24% and its recovery was 96.8% by adjusting the pI to 3.5. Maximum activity of the immobilized cellulase was achieved at 60 °C (pH 5.0), while free cellulase exhibited maximum activity at 55 °C (pH 5.0). The immobilized cellulase retained 83.1% of its initial activity after repeated five cycles of hydrolysis reaction. P(MDB) is a promising carrier for immobilizing enzymes with high and low optimum pH due to its dissolving characteristics.

  17. Immobilized Lactase in the Biochemistry Laboratory

    Science.gov (United States)

    Allison, Matthew J.; Bering, C. Larry

    1998-10-01

    Immobilized enzymes have many practical applications. They may be used in clinical, industrial, and biotechnological laboratories and in many clinical diagnostic kits. For educational purposes, use of immobilized enzymes can easily be taught at the undergraduate or even secondary level. We have developed an immobilized enzyme experiment that combines many practical techniques used in the biochemistry laboratory and fits within a three-hour time frame. In this experiment, lactase from over-the-counter tablets for patients with lactose intolerance is immobilized in polyacrylamide, which is then milled into small beads and placed into a chromatography column. A lactose solution is added to the column and the eluant is assayed using the glucose oxidase assay, available as a kit. We have determined the optimal conditions to give the greatest turnover of lactose while allowing the immobilized enzymes to be active for long periods at room temperature.

  18. Immobilizing Biomolecules Near the Diffraction Limit

    DEFF Research Database (Denmark)

    Skovsen, Esben; Petersen, Maria Teresa Neves; Gennaro, Ane Kold Di

    2009-01-01

    Our group has previously shown that biomolecules containing disulfide bridges in close proximity to aromatic residues can be immobilized, through covalent bonds, onto thiol derivatized surfaces upon UV excitation of the aromatic residue(s). We have also previously shown that our new technology can...... be used to print arrays of biomolecules and to immobilize biomolecules according to any specific pattern on a planar substrates with micrometer scale resolution. In this paper we show that we can immobilize proteins according to diffraction patterns of UV light. We also show that the feature size...... of the immobilized patterns can be as small as the diffraction limit for the excitation light, and that the immobilized patterns correspond to the diffraction pattern used to generate it. The flexibility of this new technology will in principle make it possible to create any pattern of biomolecules onto a substrate...

  19. Immobilization of whole cells using polymeric coatings

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, C.W.; Klei, H.E.; Sunstrom, D.V.; Voronka, P.J.; Scott, C.D. (ed.)

    1986-01-01

    A cell immobilization procedure was developed using latex coatings on solid particles. The method's widespread applicability has been demonstrated by successfully immobilizing Saccharomyces cerevisiae (ethanol production), Bacillus subtilis (tryptophan production). Penicillium chrysogenum (penicillin G production), and Escherichia coli (aspartic acid production). In contrast to other immobilization methods, this procedure produces a pellicular particle that is porous, allowing rapid substrate and gas transfer, has a hard core to avoid compression in large beds, and is dense to allow use in fluidized beds. The immobilization procedure was optimized with S. cerevisiae. Kinetic constants obtained were used to calculate effectiveness factors to show that there was minimal intraparticle diffusion resistance. Reactors utilizing the optimized particles were run for 300 hours to evaluate immobilized particle half-life which was 250 hours.

  20. Small-Column Cesium Ion Exchange Elution Testing of Spherical Resorcinol-Formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Garrett N.; Russell, Renee L.; Peterson, Reid A.

    2011-10-21

    This report summarizes the work performed to evaluate multiple, cesium loading, and elution cycles for small columns containing SRF resin using a simple, high-level waste (HLW) simulant. Cesium ion exchange loading and elution curves were generated for a nominal 5 M Na, 2.4E-05 M Cs, 0.115 M Al loading solution traced with 134Cs followed by elution with variable HNO3 (0.02, 0.07, 0.15, 0.23, and 0.28 M) containing variable CsNO3 (5.0E-09, 5.0E-08, and 5.0E-07 M) and traced with 137Cs. The ion exchange system consisted of a pump, tubing, process solutions, and a single, small ({approx}15.7 mL) bed of SRF resin with a water-jacketed column for temperature-control. The columns were loaded with approximately 250 bed volumes (BVs) of feed solution at 45 C and at 1.5 to 12 BV per hour (0.15 to 1.2 cm/min). The columns were then eluted with 29+ BVs of HNO3 processed at 25 C and at 1.4 BV/h. The two independent tracers allowed analysis of the on-column cesium interaction between the loading and elution solutions. The objective of these tests was to improve the correlation between the spent resin cesium content and cesium leached out of the resin in subsequent loading cycles (cesium leakage) to help establish acid strength and purity requirements.

  1. Decoration of cesium iodide nano particles on patterned carbon nanotube emitter arrays to improve their field emission

    Energy Technology Data Exchange (ETDEWEB)

    Shahi, Monika, E-mail: moni.binda@gmail.com; Gautam, S.; Shah, P. V.; Rawat, J. S.; Chaudhury, P. K. [Solid State Physics Laboratory (India); Harsh [Jamia Millia Islamia, Department of Physics (India); Tandon, R. P. [University of Delhi, Department of Physics and Astrophysics (India)

    2013-03-15

    Arrays of aligned carbon nanotube (CNT) bundles were synthesized on the pre-patterned silicon substrate using thermal chemical vapor deposition. Silicon substrate was patterned with square arrays of 10 Multiplication-Sign 10 {mu}m iron catalyst using photolithography, iron sputtering, and a lift-off process. After field emission (FE) measurement in diode configuration, CNT emitter arrays (CEAs) were decorated with cesium iodide (CsI) nano particles (NPs) using thermal evaporation with substrate heating at 300 Degree-Sign C. FE of pristine CEAs and CsI NPs decorated CEAs were carried out under same vacuum condition and constant inter-electrode separation. Pristine CEAs and CsI NPs decorated CEAs were characterized using scanning electron microscope, transmission electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Raman characterization. From FE comparison plots, it was observed that CsI NPs decoration on the CEAs had significantly lowered the turn-on electric field from 3.00 to 2.13 V/{mu}m. A remarkable improvement of more than 50 % in the current density, from 11.02 to 17.33 mA/cm{sup 2}, was also observed at a constant applied electric field of 5 V/{mu}m.

  2. Decoration of cesium iodide nano particles on patterned carbon nanotube emitter arrays to improve their field emission

    Science.gov (United States)

    Shahi, Monika; Gautam, S.; Shah, P. V.; Rawat, J. S.; Chaudhury, P. K.; Harsh; Tandon, R. P.

    2013-03-01

    Arrays of aligned carbon nanotube (CNT) bundles were synthesized on the pre-patterned silicon substrate using thermal chemical vapor deposition. Silicon substrate was patterned with square arrays of 10 × 10 μm iron catalyst using photolithography, iron sputtering, and a lift-off process. After field emission (FE) measurement in diode configuration, CNT emitter arrays (CEAs) were decorated with cesium iodide (CsI) nano particles (NPs) using thermal evaporation with substrate heating at 300 °C. FE of pristine CEAs and CsI NPs decorated CEAs were carried out under same vacuum condition and constant inter-electrode separation. Pristine CEAs and CsI NPs decorated CEAs were characterized using scanning electron microscope, transmission electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Raman characterization. From FE comparison plots, it was observed that CsI NPs decoration on the CEAs had significantly lowered the turn-on electric field from 3.00 to 2.13 V/μm. A remarkable improvement of more than 50 % in the current density, from 11.02 to 17.33 mA/cm2, was also observed at a constant applied electric field of 5 V/μm.

  3. A direct frequency comb for two-photon transition spectroscopy in a cesium vapor

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi-Chi; Wu Ji-Zhou; Li Yu-Qing; Jin Li; Ma Jie; Wang Li-Rong; Zhao Yan-Ting; Xiao Lian-Tuan; Jia Suo-Tang

    2012-01-01

    A phase-stabilized femtosecond frequency comb is used to measure high-resolution spectra of two-photon transition 62S1/2-62P1/2,3/2-82S1/2 in a cesium vapor.The broadband laser output from a femtosecond frequency comb is split into counter-propagating parts,shaped in an original way,and focused into a room-temperature cesium vapor.We obtain high-resolution two-photon spectroscopy by scanning the repetition rate of femtosecond frequency comb,and through absolute frequency measurements.

  4. Safety evaluation for packaging (onsite) for cesium chloride capsules with type W overpacks

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, J.C.

    1997-09-15

    This Safety Evaluation for Packaging (SEP) documents the evaluation of a new basket design and overpacked cesium chloride capsule payload for the Beneficial Uses Shipping System (BUSS) Cask in accordance with the onsite transportation requirements of the Hazardous Material Packaging and Shipping manual, WHC-CM-2-14. This design supports the one-time onsite shipment of 16 cesium chloride capsules with Type W overpacks from the 324 Building to the 224T Building at the Waste Encapsulation and Storage Facility (WESF). The SEP is valid for a one-time onsite shipment or until August 1, 1998, whichever occurs first.

  5. Computational study of organo-cesium complexes and the possibility of lanthanide/actinide ions substitution

    Science.gov (United States)

    Rabanal-León, Walter A.; Martinez-Ariza, Guillermo; Roberts, Sue A.; Hulme, Christopher; Arratia-Pérez, Ramiro

    2015-11-01

    Relativistic DFT calculations suggest that two organo-cesium complexes studied herein afford large HOMO-LUMO gaps of around 2.4 eV with the PBE xc-functional, which accounts for their stability. Energy decomposition studies suggest these two complexes are largely ionic with about 20% covalency. However, when the Cs+ ions are substituted by the isoelectronic La3+ and Th4+, their predicted ionicity decreases significantly. The significant increase in covalence indicates that employing Ugi reaction cascades that afford tetramic acid-based organo-cesium complexes may be extended to La3+ and Th4+ organometallics.

  6. Heat Transfer During Evaporation of Cesium From Graphite Surface in an Argon Environment

    Directory of Open Access Journals (Sweden)

    Bespala Evgeny

    2016-01-01

    Full Text Available The article focuses on discussion of problem of graphite radioactive waste formation and accumulation. It is shown that irradiated nuclear graphite being inalienable part of uranium-graphite reactor may contain fission and activation products. Much attention is given to the process of formation of radioactive cesium on the graphite element surface. It is described a process of plasma decontamination of irradiated graphite in inert argon atmosphere. Quasi-one mathematical model is offered, it describes heat transfer process in graphite-cesium-argon system. Article shows results of calculation of temperature field inside the unit cell. Authors determined the factors which influence on temperature change.

  7. Filter Performance of a Cesium Faraday Optical Filter at 852 nm

    Institute of Scientific and Technical Information of China (English)

    掌蕴东; 贾晓玲; 毕勇; 马祖光; 王骐

    2002-01-01

    We have investigated a cesium Faraday filter at 852nm in relatively weak and strong magnetic fields, theoretically and experimentally. With a cesium cell of 0.02m length in an axial magnetic field of 0.06T, the line-centre operation has been achieved. The calculated peak transmission reached 99% with a full width at half maximum (FWHM) bandwidth of only 3.9 GHz. The measured FWHM bandwidth of the filter is 3.29 GHz, which is in general agreement with the theoretical result.

  8. Concentration Ratios for Cesium and Strontium in Produce Near Los Alamos

    Energy Technology Data Exchange (ETDEWEB)

    S. Salazar, M.McNaughton, P.R. Fresquez

    2006-03-01

    The ratios of the concentrations of radionuclides in produce (fruits, vegetables, and grains) to the concentrations in the soil have been measured for cesium and strontium at locations near Los Alamos. The Soil, Foodstuffs, and Biota Team of the Meteorology and Air Quality Group of the Los Alamos National Laboratory (LANL) obtained the data at locations within a radius of 50 miles of LANL. The concentration ratios are in good agreement with previous measurements: 0.01 to 0.06 for cesium-137 and 0.1 to 0.5 for strontium-90 (wet-weight basis).

  9. Uranium Immobilization in Wetland Soils

    Science.gov (United States)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    stronger for the mesocosms with the higher Fe(II) load. Analysis via XANES showed that a fraction (up to ~1/3) of uranium was reduced to U(IV), for mesocosms operated under low iron loading, indicating that iron cycling in the rhizosphere also results in uranium reduction and immobilization. For mesocosms operating under the higher iron loading, the fraction of uranium immobilized as U(IV) was much lower, indicating that uranium co-precipitation with iron might have been the dominant immobilization process. In parallel to these mesocosm experiments, dialysis samplers have been deployed at the Savannah River National Laboratory near a creek with uranium contamination, to determine dissolved species, including Fe(II) and U(VI) in these wetland soils and their seasonal variability. The results show that there is a strong seasonal variability in dissolved iron and uranium, indicating a strong immobilization during the growing season, which is consistent with the mesocosm experimental results that the rhizosphere iron and uranium cycling are closely linked.

  10. Plutonium Immobilization Project Baseline Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  11. RAMESES publication standards: realist syntheses

    Directory of Open Access Journals (Sweden)

    Wong Geoff

    2013-01-01

    Full Text Available Abstract Background There is growing interest in realist synthesis as an alternative systematic review method. This approach offers the potential to expand the knowledge base in policy-relevant areas - for example, by explaining the success, failure or mixed fortunes of complex interventions. No previous publication standards exist for reporting realist syntheses. This standard was developed as part of the RAMESES (Realist And MEta-narrative Evidence Syntheses: Evolving Standards project. The project's aim is to produce preliminary publication standards for realist systematic reviews. Methods We (a collated and summarized existing literature on the principles of good practice in realist syntheses; (b considered the extent to which these principles had been followed by published syntheses, thereby identifying how rigor may be lost and how existing methods could be improved; (c used a three-round online Delphi method with an interdisciplinary panel of national and international experts in evidence synthesis, realist research, policy and/or publishing to produce and iteratively refine a draft set of methodological steps and publication standards; (d provided real-time support to ongoing realist syntheses and the open-access RAMESES online discussion list so as to capture problems and questions as they arose; and (e synthesized expert input, evidence syntheses and real-time problem analysis into a definitive set of standards. Results We identified 35 published realist syntheses, provided real-time support to 9 on-going syntheses and captured questions raised in the RAMESES discussion list. Through analysis and discussion within the project team, we summarized the published literature and common questions and challenges into briefing materials for the Delphi panel, comprising 37 members. Within three rounds this panel had reached consensus on 19 key publication standards, with an overall response rate of 91%. Conclusion This project used multiple

  12. MICROBIAL HYDROLASES IMMOBILIZED ON POROUS MATRICES

    Directory of Open Access Journals (Sweden)

    MONICA DRAGOMIRESCU

    2013-07-01

    Full Text Available Starch degrading enzymes are used as feed additives to increase the digestibility of corn meal based diet in livestock and poultry. To be efficient, these enzymes have to present a good activity and stability. Immobilization by physical bonding of enzymes on a porous support is a simple and efficient method to preserve enzyme molecules in an active form and retain their activity for a period of time. The aim of this study was to stabilize an enzymatic preparation with amylase activity produced by a native strain of Bacillus amyloliquefaciens in submerged culture. The immobilization technique used was physical bonding on a porous ceramic support. The enzymatic preparation with amylase activity was used in immobilization in a liophylized form. By using the same method we immobilized also a purified Aspergillus niger amylase. For both enzymes, the optimal temperature and pH of the native and immobilized enzymes did not vary significantly. At temperature and pH values lower than the optimum, the relative activities have been higher for the immobilized Bacillus amyloliquefaciens enzyme compared to the native one. The immobilization has led to an enzymatic compound with stability at pH 3 and 37°C and in time higher than that of the free one.

  13. Treatment of landfill leachate by immobilized microorganisms

    Institute of Scientific and Technical Information of China (English)

    YE ZhengFang; YU HongYan; WEN LiLi; NI JinRen

    2008-01-01

    This paper focuses on the outcome and the main performance of the immobilized microbial that treats landfill leachate. Based on the analysis of COD and ammonia-nitrogen of the influent and effluent, research was done on the high removal efficiency of COD and ammonium nitrogen by immobilized microbial. The leachate composition was analyzed qualitatively using GC-MS before and after being treated. Biological loading of efficient microbial flora on the carrier was measured by Kjeldahl's method. Finally, the patterns of immobilized microbe were observed through scanning electron microscopy (SEM). The results showed that in immobilized microorganisms system, the efficiencies of COD and nitrogen were 98.3% and 99.9%, respectively. There was a great reduction of organic components in effluent. When the immobilized biomass on the carrier was 38 g·L-1 (H2O), the filamentous microorganism was highly developed. There was no inhibitory effect on the nitrobacteria and nitrococcus, when ammonia was over 200 mg·L-1 and NH3 over 150 mg·L-1, At a high organic loading, it still had good nitrification. This paper also compares the performance of immobilized microbial with free microbial under the same condition. The immobilized microbial technology demonstrated better than the latter in all aspects.

  14. Treatment of landfill leachate by immobilized microorganisms

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper focuses on the outcome and the main performance of the immobilized microbial that treats landfill leachate. Based on the analysis of COD and ammonia-nitrogen of the influent and effluent, research was done on the high removal efficiency of COD and ammonium nitrogen by immobilized microbial. The leachate composition was analyzed qualitatively using GC-MS before and after being treated. Biological loading of efficient microbial flora on the carrier was measured by Kjeldahl’s method. Finally, the patterns of immobilized microbe were observed through scanning electron microscopy (SEM). The results showed that in immobilized microorganisms system, the efficiencies of COD and nitrogen were 98.3% and 99.9%, respectively. There was a great reduction of organic components in effluent. When the immobilized biomass on the carrier was 38 g·L?1 (H2O), the filamentous microorganism was highly developed. There was no inhibitory effect on the nitrobacteria and nitrococcus, when ammonia was over 200 mg·L?1 and NH3 over 150 mg·L?1. At a high organic loading, it still had good nitrification. This paper also compares the performance of immobilized microbial with free microbial under the same condition. The immobilized microbial technology demonstrated better than the latter in all aspects.

  15. Surface cell immobilization within perfluoroalkoxy microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovič, Gorazd; Krivec, Matic [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Vesel, Alenka [Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia); Marinšek, Marjan [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia); Žnidaršič-Plazl, Polona, E-mail: polona.znidarsic@fkkt.uni-lj.si [Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, SI-1000 Ljubljana (Slovenia)

    2014-11-30

    Graphical abstract: - Highlights: • A very efficient approach for immobilization of cells into microreactors is presented. • It is applicable to various materials, including PFA and cyclic olefin (co)polymers. • It was used to immobilize different prokaryotic and eukaryotic microbes. • Cells were immobilized on the surface in high density and showed good stability. • Mechanisms of APTES interactions with target materials are proposed. - Abstract: Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor{sup ®} and Topas{sup ®}.

  16. Design and Fabrication of Superparamaganitic Hybrid Microspheres for Protein Immobilization

    Institute of Scientific and Technical Information of China (English)

    REN Qi; CHU Hong; CHEN Mingqing; NI Zhongbin; CHEN Qiuyun

    2011-01-01

    Superparamagnetic poly(styrene)-co-poly(2-acrylanmido-2-methyl propanesulfonic acid) (PStco-PAMPS) and poly(methylmethacrylate)-co-poly(glycidyl methacrylate) (PMMA-co-PGMA) microspheres with mean size of 170 nm were prepared by emulsion polymerization in the presence of oleic acid-coated Fe3O4 nanoparticles.The structures,morphologies,diameter and diameter distribution of the as-prepared microspheres were identified by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM).The saturation magnetizations of PSt-co-PAMPS and PMMA-co-PGMA microspheres are 21.94 and 25.07emu/g,respectively.The as-synthesized magnetic microspheres were used for immobilization of Bovine serum albumin (BSA) by physical interaction and covalent interaction respectively.The equilibrium amount of BSA immobilized onto PMMA-co-PGMA microspheres was 86.48 mg/g microspheres in 90 min,while on PSt-coPAMPS microspheres was 59.62 mg/g microspheres in 120 min.

  17. Nitrate Promotes Capsaicin Accumulation in Capsicum chinense Immobilized Placentas

    Directory of Open Access Journals (Sweden)

    Jeanny G. Aldana-Iuit

    2015-01-01

    Full Text Available In chili pepper’s pods, placental tissue is responsible for the synthesis of capsaicinoids (CAPs, the compounds behind their typical hot flavor or pungency, which are synthesized from phenylalanine and branched amino acids. Placental tissue sections from Habanero peppers (Capsicum chinense Jacq. were immobilized in a calcium alginate matrix and cultured in vitro, either continuously for 28 days or during two 14-day subculture periods. Immobilized placental tissue remained viable and metabolically active for up to 21 days, indicating its ability to interact with media components. CAPs contents abruptly decreased during the first 7 days in culture, probably due to structural damage to the placenta as revealed by scanning electron microcopy. CAPs levels remained low throughout the entire culture period, even though a slight recovery was noted in subcultured placentas. However, doubling the medium’s nitrate content (from 40 to 80 mM resulted in an important increment, reaching values similar to those of intact pod’s placentas. These data suggest that isolated pepper placentas cultured in vitro remain metabolically active and are capable of metabolizing inorganic nitrogen sources, first into amino acids and, then, channeling them to CAP synthesis.

  18. Immobilization of biomolecules on semiconductor surfaces

    Science.gov (United States)

    Joensson, U.; Malmqvist, M.; Nilsson, H.; Olofsson, G.; Roennberg, I.

    1983-09-01

    A reproducible, stable and functional introduction of reactive groups on oxide covered silicon surfaces used in chemically sensitive field effect transistors and optical methods based on light reflection is described. Biomolecules, such as antibodies, antigens and enzymes, were covalently attached to the surface modified silicon via a thiol disulfide exchange reaction. The immobilization technique eliminates the risk of crosslinking and homopolymerization, giving monolayer coverage in close contact with the surface. The technique was used for immobilized protein A and interaction of such surfaces with immunoglobulins. The result was evaluated by in situ ellipsometry, which gives the amount of immobilized and interacting material on the surfaces.

  19. Immobilization of Peroxidase onto Magnetite Modified Polyaniline

    Directory of Open Access Journals (Sweden)

    Eduardo Fernandes Barbosa

    2012-01-01

    Full Text Available The present study describes the immobilization of horseradish peroxidase (HRP on magnetite-modified polyaniline (PANImG activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25% obtained for PANIG with an efficiency of 100% (active protein. The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity.

  20. Cellulose hydrolysis by immobilized Trichoderma reesei cellulase.

    Science.gov (United States)

    Jones, Paetrice O; Vasudevan, Palligarnai T

    2010-01-01

    Cellulose hydrolysis by immobilized Trichoderma reesei cellulase in the presence of a low viscosity ionic liquid, 1-ethyl-3-methylimidazolium diethyl phosphate (EMIM-DEP), was investigated. Preparation of the carrier-free immobilized cellulase was optimized with respect to concentration of the cross-linker and the type of precipitant. The addition of 2% (v/v) EMIM-DEP during hydrolysis gave an initial reaction rate 2.7 times higher than the hydrolysis rate with no ionic liquid. The initial yield after 2 h was 0.7 g glucose/g cellulose, and the carrier-free immobilized cellulase (CFIC) was effectively re-used five times.

  1. POROUS SILICA NANO-TUBE AS HOST FOR ENZYME IMMOBILIZATION

    Institute of Scientific and Technical Information of China (English)

    Haomin Ding; Lixiong Wen; Jianfeng Chen

    2004-01-01

    With their hollow morphology and large openings, the as-synthesized porous silica nano-tubes (NTPS),prepared through a sol-gel routine by using nano-sized needle-shaped CaCO3 particles as templates, were used as host for enzyme immobilization. Bioimmobilization study showed that enzyme molecules could not only be adsorbed on the external surface of NTPS but also entrapped in their inner hollow cores, leading to higher enzyme loading capacities of NTPS (more than 350 mg/g silica) in a shorter time, as compared to common porous silica (less than 50 mg/g) and most conventional mesoporous silica materials (less than 100 mg/g).

  2. Electromagnetically-induced transparency in a multi-V-type system in cesium atomic vapour

    Institute of Scientific and Technical Information of China (English)

    赵建明; 尹王保; 汪丽蓉; 肖连团; 贾锁堂

    2002-01-01

    Electromagnetically-induced transparency is observed in a three-level multi-V-type system in cesium vapour atroom temperature. The absorption property is measured and the hyperfine structures of atomic states can be determined.The results of the experiment agree with the theoretical analysis.

  3. Cyclotron production of cesium radionuclides as analogues for francium-221 biodistribution

    Science.gov (United States)

    Finn, R.; McDevitt, M.; Sheh, Y.; Lom, C.; Qiao, J.; Cai, S.; Burnazi, E.; Nacca, A.; Pillarsetty, N.; Jaggi, J.; Scheinberg, D.

    2005-12-01

    In our clinical investigations focussing on improved therapeutic treatment of specific tumors we have concentrated on a targeted therapy approach utilizing designed radiolabeled monoclonal antibodies as the cytotoxic reagent. The physical characteristics of the alpha particle emitting radionuclide bismuth-213 including the short half-life of 45.6 min, has shown promise for the treatment of specific cancers such as leukemias and lymphomas or micrometastatic carcinomas. In an effort to increase the cytocidal effect of the HuM195, a humanized monoclonal antibody carrier to the CD33 antigen expressed on leukemia cells, our focus is directed toward an "internal" nano-generator composed of Ac-225 radionuclide, the parent of the bismuth-213. The actinium-225 radionuclide decays through several short-lived, alpha emitting daughters including francium-221, astatine-217 and bismuth-213. In order to study the biodistribution and the pharmacokinetics of the individual daughter nuclide, francium-221, the cyclotron production and separation of cesium radionuclides, specifically cesium-132, from a natural xenon gas target was undertaken. The choice of cesium as an analogue for francium was predicated upon both elements being in Group 1A alkali metals and cesium radionuclide possesses a sufficient half-life to allow biodistribution studies to be performed. The preliminary experimental results of this investigation are presented.

  4. Deciphering the measured ratios of Iodine-131 to Cesium-137 at the Fukushima reactors

    CERN Document Server

    Matsui, T

    2011-01-01

    We calculate the relative abundance of the radioactive isotopes Iodine-131 and Cesium-137 produced by nuclear fission in reactors and compare it with data taken at the troubled Fukushima Dai-ichi nuclear power plant. The ratio of radioactivities of these two isotopes can be used to obtain information about when the nuclear reactions terminated.

  5. Observation of microporous cesium salts of 12-tungstosilicic acid using scanning transmission electron microscopy.

    Science.gov (United States)

    Hiyoshi, Norihito; Kamiya, Yuichi

    2015-06-21

    Heteropolyanions and their arrays in microporous cesium salts of 12-tungstosilicic acid, Cs2.5H1.5[SiW12O40] and Cs4.0[SiW12O40], were observed by aberration-corrected scanning transmission electron microscopy. Microstructures that form micropores in the polyoxometalates were visualized.

  6. Assessment of commercially available ion exchange materials for cesium removal from highly alkaline wastes

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, K.P.; Kim, A.Y.; Kurath, D.E.

    1996-04-01

    Approximately 61 million gallons of nuclear waste generated in plutonium production, radionuclide removal campaigns, and research and development activities is stored on the Department of Energy`s Hanford Site, near Richland, Washington. Although the pretreatment process and disposal requirements are still being defined, most pretreatment scenarios include removal of cesium from the aqueous streams. In many cases, after cesium is removed, the dissolved salt cakes and supernates can be disposed of as LLW. Ion exchange has been a leading candidate for this separation. Ion exchange systems have the advantage of simplicity of equipment and operation and provide many theoretical stages in a small space. The organic ion exchange material Duolite{trademark} CS-100 has been selected as the baseline exchanger for conceptual design of the Initial Pretreatment Module (IPM). Use of CS-100 was chosen because it is considered a conservative, technologically feasible approach. During FY 96, final resin down-selection will occur for IPM Title 1 design. Alternate ion exchange materials for cesium exchange will be considered at that time. The purpose of this report is to conduct a search for commercially available ion exchange materials which could potentially replace CS-100. This report will provide where possible a comparison of these resin in their ability to remove low concentrations of cesium from highly alkaline solutions. Materials which show promise can be studied further, while less encouraging resins can be eliminated from consideration.

  7. Evaluation of Factors Affecting Cesium Extraction Performance by Calix[4]Arene Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Rumppe, J.L.; Delmau, L.

    2004-01-01

    Novel aza-crown derivatives of dioctyloxy-calix[4]arene crown-6 were examined for their cesium extraction performance at different pH levels. These studies are of interest in addressing high-level waste tank remediation and the removal of 137Cs, a major contributor to heat and radiation generation. Preliminary studies were done to assess the performance of these calixarene compounds under varying conditions. Results showed an increase of cesium extraction with pH as well as expected trends in diluent effects and anion selectivity. Poor extraction performance of some aza-crown derivatives raised questions regarding the possibility of intramolecular hydrogen-bonding. A novel methylated derivative was used to address these questions. Additional experiments were conducted to determine the extraction effect on pH. Results indicate an increase in cesium extraction with pH, as shown in preliminary studies. Mono-aza derivatives were shown to exhibit better cesium extraction performance than their di-aza counterparts. The methylated derivative showed poorer extraction performance than the non-methylated derivative, indicating that completely removing the possibility of intramolecular hydrogen-bonding has negative effects on extraction performance. This suggests that the hydrogen-bonding facilitates anion co-extraction, which would lead to better overall extraction. Mono-aza derivatives were shown to cause unexpected changes in pH. This could possibly be attributed to protonation of the calix crown.

  8. Carbon, cesium and iodine isotopes in Japanese cedar leaves from Iwaki, Fukushima

    DEFF Research Database (Denmark)

    Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.;

    2016-01-01

    Japanese cedar leaves from Iwaki, Fukushima were analyzed for carbon, cesium and iodine isotopic compositions before and after the 2011 nuclear accident. The Δ14C values reflect ambient atmospheric 14C concentrations during the year the leaves were sampled/defoliated, and also previous year...

  9. X-Band PLL Synthesizer

    OpenAIRE

    P. Kutin; Vagner, P.

    2006-01-01

    This paper deals with design and realization of a PLL synthesizer for the microwave X−band. The synthesizer is intended for use as a local oscillator in a K−band downconverter. The design goal was to achieve very low phase noise and spurious free signal with a sufficient power level. For that purpose a low phase noise MMIC VCO was used in phase locked loop. The PLL works at half the output frequency, therefore there is a frequency doubler at the output of the PLL. The output signal ...

  10. Frequency synthesizers concept to product

    CERN Document Server

    Chenakin, Alexander

    2011-01-01

    A frequency synthesizer is an electronic system for generating any of a range of frequencies from a single fixed oscillator. They are found in modern devices like radio receivers, mobile phones, and GPS systems. This comprehensive resource offers RF and microwave engineers a thorough overview of both well-established and recently developed frequency synthesizer design techniques. Professionals find expert guidance on all design aspects, including main architectures, key building blocks, and practical circuit implementation. Engineers learn the development process and gain a solid understanding

  11. Preparation and characterization of cesium-137 aluminosilicate pellets for radioactive source applications

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, F.J.; Tompkins, J.A.; Haff, K.W.; Case, F.N.

    1981-07-01

    Twenty-seven fully loaded /sup 137/Cs aluminosilicate pellets were fabricated in a hot cell by the vacuum hot pressing of a cesium carbonate/montmorillonite clay mixture at 1500/sup 0/C and 570 psig. Four pellets were selected for characterization studies which included calorimetric measurements, metallography, scanning electron microscope and electron backscattering (SEM-BSE), electron microprobe, x-ray diffraction, and cesium ion leachability measurements. Each test pellet contained 437 to 450 curies of /sup 137/Cs as determined by calorimetric measurements. Metallographic examinations revealed a two-phase system: a primary, granular, gray matrix phase containing large and small pores and small pore agglomerations, and a secondary fused phase interspersed throughout the gray matrix. SEM-BSE analyses showed that cesium and silicon were uniformly distributed throughout both phases of the pellet. This indicated that the cesium-silicon-clay reaction went to completion. Aluminum homogeneity was unconfirmed due to the high background noise associated with the inherent radioactivity of the test specimens. X-ray diffraction analyses of both radioactive and non-radioactive aluminosilicate pellets confirmed the crystal lattice structure to be pollucite. Cesium ion quasistatic leachability measurements determined the leach rates of fully loaded /sup 137/Cs sectioned pollucite pellets to date to be 4.61 to 34.4 x 10/sup -10/ kg m/sup -2/s/sup -1/, while static leach tests performed on unsectioned fully loaded pellets showed the leach rates of the cesium ion to date to be 2.25 to 3.41 x 10/sup -12/ kg m/sup -2/s/sup -1/. The cesium ion diffusion coefficients through the pollucite pellet were calculated using Fick's first and second laws of diffusion. The diffusion coefficients calculated for three tracer level /sup 137/Cs aluminosilicate pellets were 1.29 x 10/sup -16/m/sup 2/s/sup -1/, 6.88 x 10/sup -17/m/sup 2/s/sup -1/, and 1.35 x 10/sup -17/m/sup 2/s/sup -1

  12. Use of mesoporous MnO2 as a support for immobilization of lipase from Candida rugosa

    Directory of Open Access Journals (Sweden)

    Babaei Mahsa

    2014-01-01

    Full Text Available In this study, immobilization of lipase from Candida rugosa on mesoporous manganese dioxide by adsorption method was carried out and the effect of three immobilization variables including temperature, process time and enzyme/support ratio on immobilization efficiency were studied. The characteristics of synthesized MnO2 and lipase-bound MnO2 were investigated by scanning electron microscopy (SEM, transmission electron microscopy (TEM and Fourier Transform Infrared Spectroscopy (FT-IR methods. The porous property of the support particles was also studied by X-ray diffraction (XRD and Brunauer, Emmett, and Teller (BET measurements. Thermal stability of immobilized lipase was determined to be better than that of free enzyme. Also the operational stability of lipase-bound MnO2 was studied and showed an almost strong attachment of enzyme to support. The Michaelis-Menten kinetic parameters (Km and Vmax were also determined for both free and immobilized lipases. It was observed that there is an increase of the Km value (672.96 mg/ml and a decrease of the Vmax value (130.99 U/mg for the immobilized enzyme comparing with the corresponding values of the free lipase.

  13. Immobilization of Rocky Flats Graphite Fines Residue

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T.S.

    1999-04-06

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  14. Optimization of adsorptive immobilization of alcohol dehydrogenases.

    Science.gov (United States)

    Trivedi, Archana; Heinemann, Matthias; Spiess, Antje C; Daussmann, Thomas; Büchs, Jochen

    2005-04-01

    In this work, a systematic examination of various parameters of adsorptive immobilization of alcohol dehydrogenases (ADHs) on solid support is performed and the impact of these parameters on immobilization efficiency is studied. Depending on the source of the enzymes, these parameters differently influence the immobilization efficiency, expressed in terms of residual activity and protein loading. Residual activity of 79% was achieved with ADH from bakers' yeast (YADH) after optimizing the immobilization parameters. A step-wise drying process has been found to be more effective than one-step drying. A hypothesis of deactivation through bubble nucleation during drying of the enzyme/glass bead suspension at low drying pressure (300% residual activity was found after drying. Hyperactivation of the enzyme is probably caused by structural changes in the enzyme molecule during the drying process. ADH from Thermoanaerobacter species (ADH T) is found to be stable under drying conditions (>15 kPa) in contrast to LBADH and YADH.

  15. Nitrogenase activity of immobilized Azotobacter vinelandii.

    Science.gov (United States)

    Seyhan, E; Kirwan, D J

    1979-02-01

    As part of a program to investigate the use of biological nitrogen fixation for fertilizer ammonia production, an investigation into the immobilization of the aerobic, nitrogen-fixing bacterium, Azotobacter vinelandii was undertaken. Immobilization was acaccomplished by adsorption onto an anionic exchange cellulose (Cellex E) with loadings as high as 10'' cells/g resin. Immobilized cell preparations were tested under both batch and continuous-flow conditions. Nitrogenase activities as high as 4200 nmol/min g resin were observed as measured by the acetylene reduction assay. Immobilized cells retained their activity for as long as 117 hr in a continuous-flow reactor. Activity loss appeared to be related to the development of a variant strain.

  16. Sorption and desorption of cesium on rapakivi granite and its minerals

    Energy Technology Data Exchange (ETDEWEB)

    Huitti, T.; Hakanen, M. [Helsinki Univ. (Finland); Lindberg, A. [Geological Survey of Finland, Espoo (Finland)

    2000-04-01

    Batch sorption experiments of cesium were performed for rapakivi granite and its main minerals, and also for some fracture minerals. The main minerals quartz, potassium feldspar, plagioclase, biotite and hornblende were magnetically separated from crushed rapakivi granite. The fracture minerals were chlorite, dolomite and kaolinite. Sorption was studied in fresh and saline reference waters containing cesium in the range of 10{sup -8} to 10{sup -3} mol/l. The distribution ratios for rapakivi granite generally decreased with an increasing Cs concentration and an increasing ionic strength. For fresh rapakivi granite, the sorption behaviour was rather complex in both fresh and saline reference waters, being complex for the other alteration stages only in saline water. Sorption increased unexpectedly when the initial cesium concentration was raised to 10{sup -5} - 10{sup -4} mol/l. The sorption on rapakivi granite was non-linear, especially in saline water. Sorption was reversible for rapakivi granite. The sorption on the minerals proved to be very non-linear, especially on biotite. Sorption was also reversible for biotite and kaolinite. For the other minerals, sorption was irreversible to some degree. As to the sorption of cesium investigated by studying thin sections of rapakivi granite and their autoradiograms, the most dominating mineral was biotite. The water analyses made during the sorption experiment revealed the exchange of potassium and cesium. The corresponding changes were difficult to detect in saline water. Calculation of the R{sub d} values for the rock, based on the R{sub d} values of minerals and the portions of minerals in the rock, yielded smaller distribution ratios than the values determined for the rock. (orig.)

  17. Immobilization Technologies in Probiotic Food Production

    OpenAIRE

    Gregoria Mitropoulou; Viktor Nedovic; Arun Goyal; Yiannis Kourkoutas

    2013-01-01

    Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their poten...

  18. Immobilization Technologies in Probiotic Food Production

    Directory of Open Access Journals (Sweden)

    Gregoria Mitropoulou

    2013-01-01

    Full Text Available Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their potential future impact, which is also highlighted and assessed.

  19. Information Retrieval for Ecological Syntheses

    Science.gov (United States)

    Bayliss, Helen R.; Beyer, Fiona R.

    2015-01-01

    Research syntheses are increasingly being conducted within the fields of ecology and environmental management. Information retrieval is crucial in any synthesis in identifying data for inclusion whilst potentially reducing biases in the dataset gathered, yet the nature of ecological information provides several challenges when compared with…

  20. Laboratory Syntheses of Insect Pheromones.

    Science.gov (United States)

    Cormier, Russell A.; Hoban, James N.

    1984-01-01

    Provides background information and procedures for the multi-step synthesis of tiger moth and boll weevil pheromones (sex attractants). These syntheses require several laboratory periods. The tiger moth pheromone synthesis is suitable for introductory organic chemistry while the boll weevil pheromone is recommended for an advanced laboratory…

  1. Template-synthesized opal hydrogels

    Institute of Scientific and Technical Information of China (English)

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  2. Polyacrolein/mesoporous silica nanocomposite: Synthesis, thermal stability and covalent lipase immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Motevalizadeh, Seyed Farshad; Khoobi, Mehdi; Shabanian, Meisam [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Asadgol, Zahra; Faramarzi, Mohammad Ali [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 14176 (Iran, Islamic Republic of); Shafiee, Abbas, E-mail: ashafiee@ams.ac.ir [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Center of Excellence in Biothermodynamics, University of Tehran, Tehran (Iran, Islamic Republic of)

    2013-12-16

    In this work, new polyacrolein/MCM-41 nanocomposites with good phase mixing behavior were prepared through an emulsion polymerization technique. Mesoporous silica was synthesized by in situ assembly of tetraethyl orthosilicate (TEOS) and cetyl trimethyl ammonium bromide (CTAB). The structure and properties of polyacrolein containing nanosized MCM-41 particle (5 and 10 wt%), were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, Dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N{sub 2} adsorption techniques, and thermogravimetric (TGA) analyses. The SEM images from the final powder have revealed good dispersion of the MCM-41 nanoparticles throughout polymeric matrix with no distinct voids between two phases. The results indicated that the thermal properties of the nanocomposite were enhanced by addition of MCM-41. Thermomyces lanuginosa lipase (TLL) was used as a model biocatalyst and successfully immobilized with polyacrolein and the nanocomposite via covalent bonds with the aldehyde groups. The activity between free enzyme, polyacrolein, and MCM-41 nanocomposite (10 wt%)-immobilized TLL was compared. The immobilized lipase with the nanocomposite shows better operational stability such as pH tolerance, thermal and storage stability. In addition, the immobilized lipase with the nanocomposite can be easily recovered and retained at 74% of its initial activity after 15 time reuses. - Graphical abstract: The influence of incorporation of mesoporous MCM-41 nanoparticle with polyacrolein on the thermal properties and enzyme immobilization was investigated. - Highlights: • Polyacrolein/MCM-41 nanocomposites were prepared by emulsion polymerization method. • Thermal stability and char residues in nanocomposites were improved. • Nanocomposites significant effects on immobilization of lipase.

  3. Immobilization of Penicillin G Acylase on Magnetic Nanoparticles Modified by Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    周华从; 李伟; 寿庆辉; 高红帅; 徐芃; 邓伏礼; 刘会洲

    2012-01-01

    Functionalized ionic liquids containing ethyoxyl groups were synthesized and immobilized on magnetic silica nanoparticles (MSNP) prepared by two steps, i.e., Fe304 synthesis and silica shell growth on the surface. This magnetic nanoparticle supported ionic liquid (MNP-IL) were applied in the immobilization of penicillin G acylase (PGA). The MSNPs and MNP-ILs were characterized by themeans of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The results showed that the average size of magnetic Fe304 nanoparticles and MSNPs were -10 and -90 nm, respectively. The saturation magnetizations of magnetic Fe304 nanoparticles and MNP-ILs were 63.7 and 26.9 A'm2·kg^-1, respectively. The MNP-IL was successfully applied in the immobilization of PGA. The maximum amount of loaded enzyme-was about 209 mg·g^-1 (based on carder), and the highest enzyme activity of immobilized PGA (based on ImPGA) was 261 U·g^-1. Both the amount of loaded enzyme and the activity of ImPGA are at the same leyel of or higher than that in previous reports. After 10 consecutive operat!ons, ImPGA still mainrained 62% of its initial activity, indicating the'good recovery property of ImPGA activity. The ionic liquid modified magnetic particles integrate the magnetic properties of Fe304 and the structure-tunable properties of ionic liquids, and have extensive potential uses in protein immobilization and magnetic bioseparation. This work may open up a novel strategy to immobilize proteins by ionic liquids.

  4. TGF-beta1 immobilized tri-co-polymer for articular cartilage tissue engineering.

    Science.gov (United States)

    Chou, Cheng-Hung; Cheng, Winston T K; Lin, Chien-Cheng; Chang, Chih-Hung; Tsai, Chien-Chen; Lin, Feng-Huei

    2006-05-01

    Tri-co-polymer with composition of gelatin, hyaluronic acid and chondroitin-6-sulfate has been used to mimic the cartilage extracellular matrix as scaffold for cartilage tissue engineering. In this study, we try to immobilize TGF-beta1 onto the surface of the tri-co-polymer sponge to suppress the undesired differentiation during the cartilage growth in vitro. The scaffold was synthesized with a pore size in a range of 300-500 microm. TGF-beta1 was immobilized on the surface of the tri-co-polymer scaffold with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as a crosslinking agent. Tri-co-polymer scaffolds with and without TGF-beta1 were seeded with porcine chondrocytes and cultured in a spinner flask for 2, 4, and 6 weeks. The chondrocytes were characterized by the methods of immunohistochemical staining with anti-type II collagen and anti-S-100 protein monoclonal antibody, and RT-PCR. After culturing for 4 weeks, chondrocytes showed positive in S-100 protein, Alcian blue, and type II collagen for the scaffold with TGF-beta1 immobilization. There is no observed type I and type X collagen expression in the scaffolds from the observation of RT-PCR. In addition, the scaffold without TGF-beta1 immobilization, type X collagen, can be detected after cultured for 2 weeks. Type I collagen was progressively expressed after 4 weeks. These results can conclude that TGF-beta1 immobilized scaffold can suppress chondrocytes toward prehypertrophic chondrocytes and osteolineage cells. The tri-co-polymer sponge with TGF-beta1 immobilization should have a great potential in cartilage tissue engineering in the future.

  5. Preparation of polyacrylamide based monolith with immobilized pH gradient and its application for protein analysis

    Institute of Scientific and Technical Information of China (English)

    ZHU GuiJie; ZHANG WeiBing; ZHANG LiHua; LIANG Zhen; ZHANG YuKui

    2007-01-01

    Monolithic materials were prepared in capillaries by in situ polymerization of acrylamide, glycidyl methacrylate and N,N'-memylenebisacrylamid in the presence of trinary porogens, including 1,4-butanediol, dodecanol and dimethyl sulphoxide. With Ampholine immobilized on the monolith by chemical bonding according to their pIs, the monolithic immobilized pH gradient (M-IPG) was prepared, and applied to the separation of four standard proteins. Compared with polyacrylate based M-IPG, the hydrophilicity of the new material was improved. It could not only avoid the adsorption of proteins, but also make the synthesized procedure simple, which showed great potential in the analysis of proteins.

  6. Synthesis of magnetically modified palygorskite composite for immobilization of Candida sp. 99–125 lipase via adsorption

    Institute of Scientific and Technical Information of China (English)

    Ya Li; Jicheng Hu; Pingfang Han

    2015-01-01

    Magnetically modified palygorskite composites were synthesized withγ-Fe2O3 dispersing on the external surface of clay mineral. The magnetic clay was characterized with Fourier transform infrared, X-ray diffrac-tion, transmission electron microscopy, and vibrating sample magnetometer. Candida sp. 99–125 lipase was immobilized on magnetic palygorskite composites by physical adsorption with enzyme loading of 41.5 mg·g-1 support and enzyme activity of 2631.6 U·(g support)-1. The immobilized lipase exhibit better thermal and broader pH stability and excellent reusability compared with free lipase.

  7. Preparation of polyacrylamide based monolith with immobilized pH gradient and its application for protein analysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Monolithic materials were prepared in capillaries by in situ polymerization of acrylamide, glycidyl methacrylate and N,N′-memylenebisacrylamid in the presence of trinary porogens, including 1,4-butanediol, dodecanol and dimethyl sulphoxide. With Ampholine immobilized on the monolith by chemical bonding according to their pIs, the monolithic immobilized pH gradient (M-IPG) was prepared, and applied to the separation of four standard proteins. Compared with polyacrylate based M-IPG, the hydrophilicity of the new material was improved. It could not only avoid the adsorption of proteins, but also make the synthesized procedure simple, which showed great potential in the analysis of proteins.

  8. Surface cell immobilization within perfluoroalkoxy microchannels

    Science.gov (United States)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

  9. Peptide-modified surfaces for enzyme immobilization.

    Directory of Open Access Journals (Sweden)

    Jinglin Fu

    Full Text Available BACKGROUND: Chemistry and particularly enzymology at surfaces is a topic of rapidly growing interest, both in terms of its role in biological systems and its application in biocatalysis. Existing protein immobilization approaches, including noncovalent or covalent attachments to solid supports, have difficulties in controlling protein orientation, reducing nonspecific absorption and preventing protein denaturation. New strategies for enzyme immobilization are needed that allow the precise control over orientation and position and thereby provide optimized activity. METHODOLOGY/PRINCIPAL FINDINGS: A method is presented for utilizing peptide ligands to immobilize enzymes on surfaces with improved enzyme activity and stability. The appropriate peptide ligands have been rapidly selected from high-density arrays and when desirable, the peptide sequences were further optimized by single-point variant screening to enhance both the affinity and activity of the bound enzyme. For proof of concept, the peptides that bound to β-galactosidase and optimized its activity were covalently attached to surfaces for the purpose of capturing target enzymes. Compared to conventional methods, enzymes immobilized on peptide-modified surfaces exhibited higher specific activity and stability, as well as controlled protein orientation. CONCLUSIONS/SIGNIFICANCE: A simple method for immobilizing enzymes through specific interactions with peptides anchored on surfaces has been developed. This approach will be applicable to the immobilization of a wide variety of enzymes on surfaces with optimized orientation, location and performance, and provides a potential mechanism for the patterned self-assembly of multiple enzymes on surfaces.

  10. Biotechnological production of vanillin using immobilized enzymes.

    Science.gov (United States)

    Furuya, Toshiki; Kuroiwa, Mari; Kino, Kuniki

    2017-02-10

    Vanillin is an important and popular plant flavor, but the amount of this compound available from plant sources is very limited. Biotechnological methods have high potential for vanillin production as an alternative to extraction from plant sources. Here, we report a new approach using immobilized enzymes for the production of vanillin. The recently discovered oxygenase Cso2 has coenzyme-independent catalytic activity for the conversion of isoeugenol and 4-vinylguaiacol to vanillin. Immobilization of Cso2 on Sepabeads EC-EA anion-exchange carrier conferred enhanced operational stability enabling repetitive use. This immobilized Cso2 catalyst allowed 6.8mg yield of vanillin from isoeugenol through ten reaction cycles at a 1mL scale. The coenzyme-independent decarboxylase Fdc, which has catalytic activity for the conversion of ferulic acid to 4-vinylguaiacol, was also immobilized on Sepabeads EC-EA. We demonstrated that the immobilized Fdc and Cso2 enabled the cascade synthesis of vanillin from ferulic acid via 4-vinylguaiacol with repetitive use of the catalysts. This study is the first example of biotechnological production of vanillin using immobilized enzymes, a process that provides new possibilities for vanillin production.

  11. MICROBIAL HYDROLASES IMMOBILIZED ON POROUS MATRICES

    Directory of Open Access Journals (Sweden)

    MONICA DRAGOMIRESCU

    2009-05-01

    Full Text Available Starch degrading enzymes are used as feed additives to increase the digestibility of corn meal based dietin livestock and poultry. To be efficient, these enzymes have to present a good activity and stability.Immobilization by physical bonding of enzymes on a porous support is a simple and efficient method topreserve enzyme molecules in an active form and retain their activity for a period of time.The aim of this study was to stabilize an enzymatic preparation with amylase activity produced by a nativestrain of Bacillus amyloliquefaciens in submerged culture. The immobilization technique used wasphysical bonding on a porous ceramic support. The enzymatic preparation with amylase activity was usedin immobilization in a liophylized form. By using the same method we immobilized also a purifiedAspergillus niger amylase. For both enzymes, the optimal temperature and pH of the native andimmobilized enzymes did not vary significantly. At temperature and pH values lower than the optimum,the relative activities have been higher for the immobilized Bacillus amyloliquefaciens enzyme comparedto the native one. The immobilization has led to an enzymatic compound with stability at pH 3 and 37°Cand in time higher than that of the free one.

  12. Immobilization of Fast Reactor First Cycle Raffinate

    Energy Technology Data Exchange (ETDEWEB)

    Langley, K. F.; Partridge, B. A.; Wise, M.

    2003-02-26

    This paper describes the results of work to bring forward the timing for the immobilization of first cycle raffinate from reprocessing fuel from the Dounreay Prototype Fast Reactor (PFR). First cycle raffinate is the liquor which contains > 99% of the fission products separated from spent fuel during reprocessing. Approximately 203 m3 of raffinate from the reprocessing of PFR fuel is held in four tanks at the UKAEA's site at Dounreay, Scotland. Two methods of immobilization of this high level waste (HLW) have been considered: vitrification and cementation. Vitrification is the standard industry practice for the immobilization of first cycle raffinate, and many papers have been presented on this technique elsewhere. However, cementation is potentially feasible for immobilizing first cycle raffinate because the heat output is an order of magnitude lower than typical HLW from commercial reprocessing operations such as that at the Sellafield site in Cumbria, England. In fact, it falls within the upper end of the UK definition of intermediate level waste (ILW). Although the decision on which immobilization technique will be employed has yet to be made, initial development work has been undertaken to identify a suitable cementation formulation using inactive simulant of the raffinate. An approach has been made to the waste disposal company Nirex to consider the disposability of the cemented product material. The paper concentrates on the process development work that is being undertaken on cementation to inform the decision making process for selection of the immobilization method.

  13. Ceramification: A plutonium immobilization process

    Energy Technology Data Exchange (ETDEWEB)

    Rask, W.C. [Dept. of Energy, Golden, CO (United States); Phillips, A.G. [Rocky Flats Environmental Technology Site, Golden, CO (United States)

    1996-05-01

    This paper describes a low temperature technique for stabilizing and immobilizing actinide compounds using a combination process/storage vessel of stainless steel, in which measured amounts of actinide nitrate solutions and actinide oxides (and/or residues) are systematically treated to yield a solid article. The chemical ceramic process is based on a coating technology that produces rare earth oxide coatings for defense applications involving plutonium. The final product of this application is a solid, coherent actinide oxide with process-generated encapsulation that has long-term environmental stability. Actinide compounds can be stabilized as pure materials for ease of re-use or as intimate mixtures with additives such as rare earth oxides to increase their degree of proliferation resistance. Starting materials for the process can include nitrate solutions, powders, aggregates, sludges, incinerator ashes, and others. Agents such as cerium oxide or zirconium oxide may be added as powders or precursors to enhance the properties of the resulting solid product. Additives may be included to produce a final product suitable for use in nuclear fuel pellet production. The process is simple and reduces the time and expense for stabilizing plutonium compounds. It requires a very low equipment expenditure and can be readily implemented into existing gloveboxes. The process is easily conducted with less associated risk than proposed alternative technologies.

  14. Cation immobilization in pyrolyzed simulated spent ion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Vittorio, E-mail: vluca@cnea.gov.ar [Programa Nacional de Gestion de Residuos Radiactivos, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); Bianchi, Hugo L. [Gerencia de Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); ECyT, Universidad Nacional de General San Martin, Campus Miguelete, Ed. Tornavias, Martin de Irigoyen 3100, 1650 San Martin (Argentina); Conicet, Av. Rivadavia 1917, 1033 Buenos Aires (Argentina); Manzini, Alberto C. [Programa Nacional de Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Av. Del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)

    2012-05-15

    Significant quantities of spent ion exchange resins that are contaminated by an assortment of radioactive elements are produced by the nuclear industry each year. The baseline technology for the conditioning of these spent resins is encapsulation in ordinary Portland cement which has various shortcomings none the least of which is the relatively low loading of resin in the cement and the poor immobilization of highly mobile elements such as cesium. The present study was conducted with cationic resin samples (Lewatit S100) loaded with Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Ni{sup 2+} in roughly equimolar proportions at levels at or below 30% of the total cation exchange capacity. Low temperature thermal treatment of the resins was conducted in inert (Ar), or reducing (CH{sub 4}) gas atmospheres, or supercritical ethanol to convert the hydrated polymeric resin beads into carbonaceous materials that contained no water. This pyrolytic treatment resulted in at least a 50% volume reduction to give mechanically robust spherical materials. Scanning electron microscope investigations of cross-sections of the beads combined with energy dispersive analysis showed that initially all elements were uniformly distributed through the resin matrix but that at higher temperatures the distribution of Cs became inhomogeneous. Although Cs was found in the entire cross-section, a significant proportion of the Cs occurred within internal rings while a proportion migrated toward the outer surfaces to form a crustal deposit. Leaching experiments conducted in water at 25 Degree-Sign C showed that the divalent contaminant elements were very difficult to leach from the beads heated in inert atmospheres in the range 200-600 Degree-Sign C. Cumulative fractional loses of the order of 0.001 were observed for these divalent elements for temperatures below 500 Degree-Sign C. Regardless of the processing temperature, the cumulative fractional loss of Cs in water at 25 Degree-Sign C reached a plateau or

  15. A comparative study of free and immobilized soybean and horseradish peroxidases for 4-chlorophenol removal: protective effects of immobilization.

    Science.gov (United States)

    Bódalo, Antonio; Bastida, Josefa; Máximo, M Fuensanta; Montiel, M Claudia; Gómez, María; Murcia, M Dolores

    2008-10-01

    Horseradish peroxidase (HRP) and soybean peroxidase (SBP) were covalently immobilized onto aldehyde glass through their amine groups. The activity yield and the protein content for the immobilized SBP were higher than for the immobilized HRP. When free and immobilized peroxidases were tested for their ability to remove 4-chlorophenol from aqueous solutions, the removal percentages were higher with immobilized HRP than with free HRP, whereas immobilized SBP needs more enzyme to reach the same conversion than free enzyme. In the present paper the two immobilized derivatives are compared. It was found that at an immobilized enzyme concentration in the reactor of 15 mg l(-1), SBP removed 5% more of 4-chlorophenol than HRP, and that a shorter treatment was necessary. Since immobilized SBP was less susceptible to inactivation than HRP and provided higher 4-chlorophenol elimination, this derivative was chosen for further inactivation studies. The protective effect of the immobilization against the enzyme inactivation by hydrogen peroxide was demonstrated.

  16. Acquired long QT syndrome and monomorphic ventricular tachycardia after alternative treatment with cesium chloride for brain cancer.

    Science.gov (United States)

    Dalal, Anuj K; Harding, John D; Verdino, Ralph J

    2004-08-01

    Individuals searching for symptomatic relief or a potential cure are increasingly seeking and using nontraditional therapies for their various diseases. Little is known about the potential adverse effects that patients may encounter while undergoing these alternative treatments. Cesium chloride is an unregulated agent that has been reported to have antineoplastic properties. Cesium chloride is advertised as an alternative agent for many different types of cancers and can be purchased easily on the Internet. Recently, QT prolongation and polymorphic ventricular tachycardia were reported in several patients taking cesium chloride as alternative treatment for cancer. We report acquired QT prolongation and sustained monomorphic ventricular tachycardia in a patient who self-initiated and completed a course of cesium chloride as adjunctive treatment for brain cancer.

  17. Spin-dependent asymmetry functions in the elastic and inelastic electron-cesium scattering at intermediate energies

    CERN Document Server

    Roth, B

    2001-01-01

    In this thesis the measurements of the relative differential cross section, the exchange asymmetry, the spin-orbit asymmetry, and the interference asymmetry for the electron scattering on cesium atoms from 4 to 18 eV is described. (HSI)

  18. Removal of cesium using coconut fiber in raw and modified forms for the treatment of radioactive liquid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Nella N.M. de; Nobre, Vanessa B.; Potiens Junior, Ademar J.; Sakata, Solange K., E-mail: sksakata@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Di Vitta, Patricia B. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica

    2013-07-01

    Sorption is one of the most studied methods to reduce the volume of radioactive waste streams. Cesium-137 is a radioisotope formed by the fission of uranium and it can cause health problems due to its easy assimilation by cells. The aim of this study is to evaluate the potential of coconut fiber in removing cesium from radioactive liquid wastes; this process can help in disposing radioactive waste. The experiments were performed in batch and the particle size of the fiber ranged between 0.30 mm and 0.50 mm. The fiber was treated with hydrogen peroxide in alkaline medium. The following parameters were analyzed: contact time, pH and concentration of cesium ions in aqueous solution. After the experiments the samples were filtered and cesium remaining in solution was quantified by inductively coupled plasma optical emission spectrometry. (author)

  19. Cesium Platinide Hydride 4Cs2 Pt⋅CsH: An Intermetallic Double Salt Featuring Metal Anions.

    Science.gov (United States)

    Smetana, Volodymyr; Mudring, Anja-Verena

    2016-11-14

    With Cs9 Pt4 H a new representative of ionic compounds featuring metal anions can be added to this rare-membered family. Cs9 Pt4 H exhibits a complex crystal structure containing Cs(+) cations, Pt(2-) and H(-) anions. Being a red, transparent compound its band gap is in the visible range of the electromagnetic spectrum and the ionic type of bonding is confirmed by quantum chemical calculations. This cesium platinide hydride can formally be considered as a double salt of the "alloy" cesium-platinum, or better cesium platinide, Cs2 Pt, and the salt cesium hydride CsH according to Cs9 Pt4 H≡4 Cs2 Pt⋅CsH.

  20. Enhanced Stability and Reusability of Alcohol Dehydrogenase Covalently Immobilized on Magnetic Graphene Oxide Nanocomposites.

    Science.gov (United States)

    Liu, Liangliang; Yu, Jingang; Chen, Xiaoqing

    2015-02-01

    Graphene oxide (GO) has a unique planar structure and contains many functional groups. As a functional material, it can be functionalized with biomolecules and nanomaterials for various applications. In this study, Magnetic GO (MGO) nanocomposites were synthesized according to covalent binding of amino Fe3O4 nanoparticles onto the GO surface and the as-made nanocomposites were successfully applied as supports for the immobilization of alcohol dehydrogenase (ADH). Compared with free ADH and Fe3O4 nanoparticles immobilized ADH (MNP-ADH), the MGO immobilized ADH (MGO-ADH) exhibited a wider pH stability range and a better thermal stability. Furthermore, the MGO-ADH exhibited better storage stability and reusability than MNP-ADH after recovered by magnetic separations. The MGO-ADH maintained 35.1% activity after 20 days storage and lost about 20.4% activity after ten times usage. The Michaelis constant (Km) of MGO-ADH was close to that of free ADH. The results showed the MGO nanocomposites were appropriate for the immobilization of enzyme. As a novel support, MGO nanocomposites effectively increased the stability of enzyme, allowed the reuse or continuous use of enzymes and therefore improved the potential use in practical.

  1. Effect of substrate (ZnO) morphology on enzyme immobilization and its catalytic activity

    Science.gov (United States)

    Zhang, Yan; Wu, Haixia; Huang, Xuelei; Zhang, Jingyan; Guo, Shouwu

    2011-07-01

    In this study, zinc oxide (ZnO) nanocrystals with different morphologies were synthesized and used as substrates for enzyme immobilization. The effects of morphology of ZnO nanocrystals on enzyme immobilization and their catalytic activities were investigated. The ZnO nanocrystals were prepared through a hydrothermal procedure using tetramethylammonium hydroxide as a mineralizing agent. The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system. The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay. Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker. The results showed that three-dimensional nanomultipod is more appropriate for the immobilization of enzyme used further in catalytic reaction.

  2. Synthesis and characterization of cysteine functionalized silver nanoparticles for biomolecule immobilization.

    Science.gov (United States)

    Upadhyay, Lata Sheo Bachan; Verma, Nishant

    2014-11-01

    A facile method for the aqueous phase synthesis of cysteine-functionalized silver nanoparticles by potato extract has been reported in the present work. These functionalized nanoparticles were then used for the covalent immobilization of a biomolecule, alkaline phosphatase, on its surface through carbodiimide coupling. Different reaction parameters such as cysteine concentration, reducing agent concentration, temperature, pH and reaction time were varied during the nanoparticles' formation, and their effects on plasmon resonance were studied using Ultraviolet-visible spectroscopy. Fourier transform infrared spectroscopy was used to confirm the surface modification of silver nanoparticles by cysteine and the particle size analysis was done using particle size analyzer, which showed the average nanoparticles' size of 61 nm for bare silver nanoparticles and 201 nm for the enzyme-immobilized nanoparticles. The synthesized nanoparticles were found to be highly efficient for the covalent immobilization of alkaline phosphatase on its surface and retained 67% of its initial enzyme activity (9.44 U/mg), with 75% binding efficiency. The shelf life of the enzyme-nanoparticle bioconjugates was found to be 60 days, with a 12% loss in the initial enzyme activity. With a simple synthesis strategy, high immobilization efficiency and enhanced stability, these enzyme-coated nanoparticles have the potential for further integration into the biosensor technology.

  3. Microencapsulation of alginate-immobilized bagasse with Lactobacillus rhamnosus NRRL 442: enhancement of survivability and thermotolerance.

    Science.gov (United States)

    Shaharuddin, Shahrulzaman; Muhamad, Ida Idayu

    2015-03-30

    The aim of this research was to enhance the survivability of Lactobacillus rhamnosus NRRL 442 against heat exposure via a combination of immobilization and microencapsulation processes using sugarcane bagasse (SB) and sodium alginate (NaA), respectively. The microcapsules were synthesized using different alginate concentration of 1, 2 and 3% and NaA:SB ratio of 1:0, 1:1 and 1:1.5. This beneficial step of probiotic immobilization before microencapsulation significantly enhanced microencapsulation efficiency and cell survivability after heat exposure of 90°C for 30s. Interestingly, the microcapsule of SB-immobilized probiotic could obtain protection from heat using microencapsulation of NaA concentration as low as 1%. SEM images illustrated the incorporation of immobilized L. rhamnosus within alginate matrices and its changes after heat exposure. FTIR spectra confirmed the change in functional bonding in the presence of sugarcane bagasse, probiotic and alginate. The results demonstrated a great potential in the synthesis of heat resistant microcapsules for probiotic.

  4. Effect of substrate (ZnO morphology on enzyme immobilization and its catalytic activity

    Directory of Open Access Journals (Sweden)

    Huang Xuelei

    2011-01-01

    Full Text Available Abstract In this study, zinc oxide (ZnO nanocrystals with different morphologies were synthesized and used as substrates for enzyme immobilization. The effects of morphology of ZnO nanocrystals on enzyme immobilization and their catalytic activities were investigated. The ZnO nanocrystals were prepared through a hydrothermal procedure using tetramethylammonium hydroxide as a mineralizing agent. The control on the morphology of ZnO nanocrystals was achieved by varying the ratio of CH3OH to H2O, which were used as solvents in the hydrothermal reaction system. The surface of as-prepared ZnO nanoparticles was functionalized with amino groups using 3-aminopropyltriethoxysilane and tetraethyl orthosilicate, and the amino groups on the surface were identified and calculated by FT-IR and the Kaiser assay. Horseradish peroxidase was immobilized on as-modified ZnO nanostructures with glutaraldehyde as a crosslinker. The results showed that three-dimensional nanomultipod is more appropriate for the immobilization of enzyme used further in catalytic reaction.

  5. A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng

    2010-11-01

    Full Text Available A new alcohol oxidase (AOX enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide [poly(nBA-NAS] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE. Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3. The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation and 1.11% RSD, respectively (n = 3. The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.

  6. X-Band PLL Synthesizer

    Directory of Open Access Journals (Sweden)

    P. Kutin

    2006-04-01

    Full Text Available This paper deals with design and realization of a PLL synthesizer for the microwave X−band. The synthesizer is intended for use as a local oscillator in a K−band downconverter. The design goal was to achieve very low phase noise and spurious free signal with a sufficient power level. For that purpose a low phase noise MMIC VCO was used in phase locked loop. The PLL works at half the output frequency, therefore there is a frequency doubler at the output of the PLL. The output signal from the frequency doubler is filtered by a band-pass filter and finally amplified by a single stage amplifier.

  7. The promotional effects of cesium promoter on higher alcohol synthesis from syngas over cesium-promoted Cu/ZnO/Al2O3 catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jie; Cai, Qiuxia; Wan, Yan; Wan, Shaolong; Wang, Li; Lin, Jingdong; Mei, Donghai; Wang, Yong

    2016-09-02

    In this study, the promotional effects of cesium promoter on higher alcohol (C2+OH) synthesis from syngas over Cs-Cu/ZnO/Al2O3 catalysts were investigated using a combined experimental and theoretical density functional theory (DFT) calculation method. In the presence of cesium, the C2+OH productivity increases from 77.1 g•kgcat-1•h-1 to 157.3 g•kgcat-1•h-1 at 583 K due to the enhancement of the initial C–C bond formation. Detailed analysis of chain growth probabilities (CGPs) confirms that initial C–C bond formation is the rate-determining step in the temperature range of 543-583 K. Addition of cesium promoter significantly increases the productivities of 2-methyl-1-propanol, while the CGPs values (C3* to 2-methyl-C3*) is almost unaffected. With the assistance of cesium promoter, the CGPs of the initial C–C bond formation step (C1* to C2*) could be increased from 0.13 to 0.25 at 583 K. DFT calculations indicate that the initial C–C bond formation is mainly contributed by the HCO+HCO coupling reaction over the ZnCu(211) model surface. In the presence of the Cs2O, the stabilities of key reaction intermediates such as HCO and H2CO are enhanced which facilitates both HCO+HCO and HCO+H2CO coupling reaction steps with lower activation barriers over the Cs2O-ZnCu(211) surface. The promotional effects of cesium on the C2+OH productivity are also benefited from the competitive CH+HCO coupling reaction over CH hydrogenation that leads to lower alkane formation. In addition, Bader charge analysis suggests that the presence of cesium ions would facilitate the nucleophilic reaction between HCO and H2CO for initial C–C bond formation. This work was supported by the National Natural Science Foundation of China (No. 91545114 and No. 91545203). We appreciate the joint PhD scholarship support from the China Scholarship Council. The authors would also like to thank the support from Collaborative Innovation Center of Chemistry for Energy Materials (2011-iChEM). DM

  8. Characteristics of Immobilized Urease on Grafted Alginate Bead Systems

    Directory of Open Access Journals (Sweden)

    Enas N. Danial

    2015-04-01

    Full Text Available This study evaluated the biological importance of immobilized urease enzyme over the free urease. The support material used for urease immobilization was alginate. Generally, the immobilization of urease in alginate gel showed a marked increase in Km and Vmax. However, the immobilized urease showed higher thermal stability than that of free enzyme. The rate of thermal inactivation of the immobilized enzyme decreased due to entrapment in gel matrix. Also, the activity of the immobilized urease was more stable in retention than that of the free enzyme during the storage in solution, although the activity of the immobilized enzyme was lower in comparison with the free enzyme. A stable immobilized system and long storage life are convenient for applications that would not be feasible with a soluble enzyme system. These results highlighted the technical and biochemical benefits of immobilized urease over the free enzyme.

  9. Solid phase syntheses of oligoureas

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)

    1997-02-19

    Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.

  10. Advances in the Glass Formulations for the Hanford Tank Waste Treatment and Immobilization Plant

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A.; Vienna, John D.; Kim, Dong Sang

    2015-01-14

    The Department of Energy-Office of River Protection (DOE-ORP) is constructing the Hanford Tank Waste Treatment and Immobilization Plant (WTP) to treat radioactive waste currently stored in underground tanks at the Hanford site in Washington. The WTP that is being designed and constructed by a team led by Bechtel National, Inc. (BNI) will separate the tank waste into High Level Waste (HLW) and Low Activity Waste (LAW) fractions with the majority of the mass (~90%) directed to LAW and most of the activity (>95%) directed to HLW. The pretreatment process, envisioned in the baseline, involves the dissolution of aluminum-bearing solids so as to allow the aluminum salts to be processed through the cesium ion exchange and report to the LAW Facility. There is an oxidative leaching process to affect a similar outcome for chromium-bearing wastes. Both of these unit operations were advanced to accommodate shortcomings in glass formulation for HLW inventories. A by-product of this are a series of technical challenges placed upon materials selected for the processing vessels. The advances in glass formulation play a role in revisiting the flow sheet for the WTP and hence, the unit operations that were being imposed by minimal waste loading requirements set forth in the contract for the design and construction of the plant. Another significant consideration to the most recent revision of the glass models are the impacts on resolution of technical questions associated with current efforts for design completion.

  11. Two-step method for preparation of NaA-X zeolite blend from fly ash for removal of cesium ions.

    Science.gov (United States)

    El-Naggar, M R; El-Kamash, A M; El-Dessouky, M I; Ghonaim, A K

    2008-06-15

    Pure zeolites can be synthesized from silica extracts obtained from fly ash by alkaline leaching. The extraction potential of industrial by-product fly ash was investigated under repeated fusion process conditions. The amount of extracted silica was 131.43 g/kg ash while the amount extracted alumina was limited to 41.72 g/kg ash. The results of zeolite synthesis from the Si-bearing extracts demonstrated that pure zeolites with high cation exchange capacity (4.624 meq/g) can be produced. The sorption potential of synthesized A-X zeolite blend for the removal of cesium ions has been investigated. The influences of pH, contact time and temperature have been reported. Thermodynamic parameters such as changes in Gibbs free energy (DeltaG degrees), enthalpy (DeltaH degrees) and entropy (DeltaS degrees) were calculated. A comparison of kinetic models applied to the sorption data was evaluated for pseudo first-order, pseudo second-order and homogeneous particle diffusion models. The results showed that both the pseudo second-order and the homogeneous particle diffusion models were found to best correlate the experimental rate data.

  12. Experiments and simulations for the dynamics of cesium in negative hydrogen ion sources for ITER N-NBI

    Energy Technology Data Exchange (ETDEWEB)

    Gutser, Raphael

    2010-07-21

    The injection of fast neutral particles (NBI) into a fusion plasma is an important method for plasma heating and current drive. A source for negative deuterium ions delivering an 1 MeV beam that is accelerated to a specific energy and neutralized by a gas target is required for the ITER-NBI. Cesium seeding is required to extract high negative ion current densities from these sources. The optimization of the cesium homogeneity and control are major objectives to achieve the source requirements imposed by ITER. Within the scope of this thesis, the Monte Carlo based numerical transport simulation CsFlow3D was developed, which is the first computer model that is capable of simulating the flux and the accumulation of cesium on the surfaces of negative-ion sources. Basic studies that support the code development were performed at a dedicated experiment at the University of Augsburg. Input parameters of the ad- and desorption of cesium at ion source relevant conditions were taken from systematic measurements with a quartz micro balance, while the injection rate of the cesium oven at the ion source was determined by surface ionization detection. This experimental setup was used for further investigations of the work function of cesium-coated samples during plasma exposure. (orig.)

  13. Immobilization of thermolysin to polyamide nonwoven materials.

    Science.gov (United States)

    Moeschel, Klaus; Nouaimi, Meryem; Steinbrenner, Christa; Bisswanger, Hans

    2003-04-20

    In the last few years, an increasing number of biotechnological techniques have been applied to the restoration and conservation of works of art, paintings, old maps, and papers or books. Enzymes can solve problems that give restorers difficulties, although for many applications it is not possible to use soluble enzymes; therefore, it is necessary to look for suitable carriers for immobilization. Different methods for covalent immobilization of enzymes to polyamide nonwovens were tested, using thermolysin as an example. Two distinct strategies were pursued: (1). controlled, partial hydrolysis of the polymer and subsequent binding of the enzyme to the released amino and carboxy groups; and (2). attachment of reactive groups directly to the polyamide without disintegrating the polymeric structure (O-alkylation). Different spacers were used for covalent fixation of the enzyme in both cases. The enzyme was fixed to the released amino groups by glutaraldehyde, either with or without a spacer. Either way, active enzyme could be immobilized to the matrix. However, intense treatment caused severe damage to the stability of the nonwoven fabric, and reduced the mechanical strength. Conditions were investigated to conserve the nonwoven fabric structure while obtaining near-maximum immobilized enzyme activity. Immobilization of the enzyme to the released carboxy group after acid hydrolysis was performed using dicyclohexylcarbodiimide. In comparison to the enzyme bound via the amino group, the yield of immobilized enzyme activity was slightly lower when benzidine was taken as spacer and still lower with a 1,6-hexanediamine spacer. O-alkylation performed with dimethylsulfate caused severe damage to the nonwoven fabric structure. Considerably better results were obtained with triethyloxonium tetrafluoroborate. As the spacers 1,6-hexanediamine and adipic acid dihydrazide were used, activation for immobilizing thermolysin was performed with glutaraldehyde, adipimidate, and azide

  14. Excess Weapons Plutonium Immobilization in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, L.; Borisov, G.B.

    2000-04-15

    The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R&D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R&D on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the excellent

  15. Biomolecule immobilization techniques for bioactive paper fabrication.

    Science.gov (United States)

    Kong, Fanzhi; Hu, Yim Fun

    2012-04-01

    Research into paper-based sensors or functional materials that can perform analytical functions with active recognition capabilities is rapidly expanding, and significant research effort has been made into the design and fabrication of bioactive paper at the biosensor level to detect potential health hazards. A key step in the fabrication of bioactive paper is the design of the experimental and operational procedures for the immobilization of biomolecules such as antibodies, enzymes, phages, cells, proteins, synthetic polymers and DNA aptamers on a suitably prepared paper membrane. The immobilization methods are concisely categorized into physical absorption, bioactive ink entrapment, bioaffinity attachment and covalent chemical bonding immobilization. Each method has individual immobilization characteristics. Although every biomolecule-paper combination has to be optimized before use, the bioactive ink entrapment method is the most commonly used approach owing to its general applicability and biocompatibility. Currently, there are four common applications of bioactive paper: (1) paper-based bioassay or paper-based analytical devices for sample conditioning; (2) counterfeiting and countertempering in the packaging and construction industries; (3) pathogen detection for food and water quality monitoring; and (4) deactivation of pathogenic bacteria using antimicrobial paper. This article reviews and compares the different biomolecule immobilization techniques and discusses current trends. Current, emerging and future applications of bioactive paper are also discussed.

  16. Liver alcohol dehydrogenase immobilized on polyvinylidene difluoride.

    Science.gov (United States)

    Roig, M G; Bello, J F; Moreno de Vega, M A; Cachaza, J M; Kennedy, J F

    1990-01-01

    A physical method for immobilization of liver alcohol dehydrogenase (ADH) by hydrophobic adsorption onto a supporting membrane of polyvinylidene difluoride (PVDF) was performed. Simultaneously, a physicochemical characterization of the immobilized enzyme regarding its kinetic behaviour was performed. The activity/pH profile observed points to an effect of pH on activity that is completely different from the case of ADH in solution. The disturbance in the typical bell-shaped profile owing to the fact that the enzyme was immobilized is explained on the basis of a potent limitation to the diffusion of the protons in the support. The findings of the present work also reveal the existence of an effect that limits free external diffusion of the substrate towards and/or the product from the support; this effect seems to be the determinant of the overall rate of the enzymatic reaction and is thus of great importance in the effective kinetic behaviour (v([S])) of immobilized ADH, whose kinetic behaviour is complex (non-Michaelian), as may be seen from the lack of linearity observed in the corresponding double reciprocal and Eadie-Hofstee plots. By non-linear regression numerical analysis of the v([S]) data and application of the F-test for model discrimination, the minimum rate equation necessary to describe the intrinsic kinetic behaviour of PVDF-immobilized ADH proved to be one of the polynomial quotient type of degree 2:2 (in substrate concentration).

  17. Immobilization of Spirulina subsalsa for removal of triphenyltin from water.

    Science.gov (United States)

    Huang, Guo-Lan; Zhihui, Song

    2002-07-01

    Spirulina subsalsa is immobilized with alginate, which increases the growth rate, chlorophyll content, phycocyanin content and nitrate reductase activity. Immobilized Spirulina subsalsa with alginate increases absorption of triphenyltin chloride (TPT). The phycocyanin of immobilized Spirulina subsalsa is more sensitive to TPT then free alga. The immobilization enhances the toxic effect of TPT on nitrate reductase activity of Spirulina subsalsa. Experimental results demonstrate that the immobilization of Spirulina subsalsa is feasible. Removal of TPT by immobilized Spirulina subsalsa reaches 68%. Biosorption mechanism of TPT by Spirulina subsalsa should be further studied.

  18. Kelvin probe studies of cesium telluride photocathode for the AWA photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez, D.; Wisniewski, E. E.; Yusof, Z.; Harkay, K.; Spentzouris, L.; Terry, J. [Physics Department at Illinois Institute of Technology, Chicago, IL 60616 and High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); High Energy Physics Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Accelerator Science Division at Argonne National Laboratory, Lemont, IL 60439 (United States); Physics Department at Illinois Institute of Technology, Chicago, IL 60616 (United States)

    2012-12-21

    Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (> 1%), is robust in a photoinjector, and long lifetime. This photocathode is fabricated in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch ({approx}50 nC) in a long bunch train. We present some results from a study of the work function of cesium telluride photocathode using the Kelvin Probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV light exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating.

  19. Low Level Gamma Spectroscopy Measurements of Radium and Cesium in Lucerne (Medicago Sativa)

    Science.gov (United States)

    Fokapić, S.; Bikit, I.; Mrđa, D.; Vesković, M.; Slivka, J.; Mihaljev, Ž.; Ćupić, Ž.

    2007-04-01

    Nineteen years after Chernobyl nuclear accident, activity concentration of 137Cs still could be detected in food and soil samples in Central and Eastern Europe. In this paper radiation levels of radium and cesium in Lucerne will be presented. It is a perennial plant with a deep root system and it is widely grown throughout the world as forage for cattle. The samples of Lucerne were taken from twelve different locations in Vojvodina in the summer period July-September 2004. The samples were specially dried on the air and after that ground, powdered and mineralized by method of dry burning on the temperature of 450°C. Gamma spectrometry measurements of the ash were performed by means of actively shielded germanium detector with maximal background reduction. For cesium 137Cs 10 mBq/kg order of magnitude detection limits were achieved.

  20. Removal of cesium ions from aqueous solution by adsorption onto local Taiwan laterite

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.-H. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Li, M.-H. [Institute of Hydrological Sciences, National Central University, Jungli 320, Taiwan (China); Yeh, W.-C.; Wei, Y.-Y. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Teng, S.-P. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China)], E-mail: spteng@ess.nthu.edu.tw

    2008-12-30

    Utilization of local Taiwan laterite (LTL) to remove aqueous cesium was investigated in this work under the conditions of various contact time, cesium (Cs) loading and temperature. Experimental results show that adsorption is instantaneous. Freundlich and Langmuir simulation results demonstrate that local Taiwan laterite has high affinity and sorption capacity for Cs at low temperatures, which may be attributed to enhanced desorption as temperature increased. Thermodynamic parameters including {delta}H, {delta}G and {delta}S were calculated and it is indicated that Cs adsorption on LTL is an exothermic, spontaneous and physical adsorption reaction. Moreover, the adsorbed Cs is distributed evenly on the LTL surface, which is confirmed by SEM/EDS mapping images. Furthermore, the absence of apparent shifting or broadening of the kaolinite signal in XRD patterns after Cs adsorption is an indication of the non-expanding characteristic of kaolinite structure.

  1. Light storage via coherent population oscillation in a thermal cesium vapor

    CERN Document Server

    de Almeida, A J F; Maynard, M -A; Laupretre, T; Bretenaker, F; Felinto, D; Goldfarb, F; Tabosa, J W R

    2014-01-01

    We report on the storage of light via the phenomenon of Coherent Population Oscillation (CPO) in an atomic cesium vapor at room temperature. In the experiment the optical information of a probe field is stored in the CPO of two ground states of a Lambda three-level system formed by the Zeeman sublevels of the hyperfine transition F = 3 - F' = 2 of cesium D2 line. We show directly that this CPO based memory is very insensitive to stray magnetic field inhomogeneities and presents a lifetime which is mainly limited only by atomic motion. A theoretical simulation of the measured spectra was also developed and is in very good agreement with the experiment.

  2. Precision mass measurements of cesium isotopes—new entries in the ISOLTRAP chronicles

    Science.gov (United States)

    Atanasov, D.; Beck, D.; Blaum, K.; Borgmann, Ch; Cakirli, R. B.; Eronen, T.; George, S.; Herfurth, F.; Herlert, A.; Kowalska, M.; Kreim, S.; Litvinov, Yu A.; Lunney, D.; Manea, V.; Neidherr, D.; Rosenbusch, M.; Schweikhard, L.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

    2017-04-01

    Alkali ion beams are among the most intense produced by the ISOLDE facility. These were the first to be studied by the ISOLTRAP mass spectrometer and ever since, new measurements have been regularly reported. Recently the masses of very neutron-rich and short-lived cesium isotopes were determined at ISOLTRAP. The isotope 148Cs was measured directly for the first time by Penning-trap mass spectrometry. Using the new results, the trend of two-neutron separation energies in the cesium isotopic chain is revealed to be smooth and gradually decreasing, similar to the ones of the barium and xenon isotopic chains. Predictions of selected microscopic models are employed for a discussion of the experimental data in the region.

  3. Accumulation of radioactive cesium released from Fukushima Daiichi Nuclear Power Plant in terrestrial cyanobacteria Nostoc commune.

    Science.gov (United States)

    Sasaki, Hideaki; Shirato, Susumu; Tahara, Tomoya; Sato, Kenji; Takenaka, Hiroyuki

    2013-01-01

    The Fukushima Daiichi Nuclear Power Plant accident released large amounts of radioactive substances into the environment and contaminated the soil of Tohoku and Kanto districts in Japan. Removal of radioactive material from the environment is an urgent problem, and soil purification using plants is being considered. In this study, we investigated the ability of 12 seed plant species and a cyanobacterium to accumulate radioactive material. The plants did not accumulate radioactive material at high levels, but high accumulation was observed in the terrestrial cyanobacterium Nostoc commune. In Nihonmatsu City, Fukushima Prefecture, N. commune accumulated 415,000 Bq/kg dry weight (134)Cs and 607,000 Bq kg(-1) dry weight (137)Cs. The concentration of cesium in N. commune tended to be high in areas where soil radioactivity was high. A cultivation experiment confirmed that N. commune absorbed radioactive cesium from polluted soil. These data demonstrated that radiological absorption using N. commune might be suitable for decontaminating polluted soil.

  4. Stark spectra of Rydberg states in atomic cesium in the vicinity of n=18

    Institute of Scientific and Technical Information of China (English)

    Dong Hui-Jie; Wang Ting; Li Chang-Yong; Zhao Jian-Ming; Zhang Lin-Jie

    2013-01-01

    The Stark structures in a cesium atom around n =18 are numerically calculated.The results show that the components of 20D states with a small azimuthal quantum number |m| shift upward a lot,and those with a large |m| shift downward a little within 1100 V/cm.All components of P states shift downward.Experimental work has been performed in ultracold atomic cesium.Atoms initially in 6P3/2 state are excited to high-n Rydberg states by a polarization light perpendicular to the field,and Stark spectra with 丨m丨=1/2,3/2,5/2 are simultaneously observed with a large linewidth for the first time.The observed spectra are analyzed in detail.The relative transition probability is calculated.The experimental results are in good agreement with our numerical computation.

  5. STUDY ON THE IMMOBILIZATION OF PAPAIN WITH A MACROPOROUS BEAD CARRIER OF COPOLYMER CONTAINING MONOMER UNITS OF N-AMINOETHYL ACRYLAMIDE AND VINYL ALCOHOL

    Institute of Scientific and Technical Information of China (English)

    Yan-feng Li; Jun-rong Li; Lian-di Fu; Yao-zeng Li

    2000-01-01

    A kind of macroporous bead carrier of copolymer containing monomer units ofN-aminoethyl acrylamide and vinyl alcohol was synthesized, i.e. the MR-AA carrier. Papain was immobilized on the carrier using glutaraldehyde as the coupling agent. The enzymatic activity of the immobilized papain was compared with free papain using casein as a substrate, and the effects of glutaraldehyde concentration, pH, temperature, time and papain amount added on the activity recovery were also investigated. The results show that the MR-AA carrier contains reactive primary amine groups, hydrophilic amido links and hydroxyl groups, as well as macroporous structures based on its matrix (MR-AV matrix), furthermore, the activity recovery of papain in the immobilization could reach 48%~58%. In comparison with free papain, the resulting immobilized papain exhibits a remarkable thermostability and better reusability.

  6. Photocatalytic oxidation of methyl orange in water phase by immobilized TiO{sub 2}-carbon nanotube nanocomposite photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yinmao [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); School of Sciences/Beijing Key Lab of Plant Resource Research and Development, Beijing Technology and Business University, Beijing 100048 (China); Tang, Dongyan [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Li, Chensha, E-mail: lichnsa@mail.tsinghua.edu.cn [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2014-03-01

    Highlights: • An immobilized photocatalyst with heterostructure of nanophase CNT-TiO{sub 2} was developed. • The unique 3-D network structure of the photocatalyst resulted in high and available surface area. • The nano-photocatalyst exhibited a high photocatalysis performance. • The immobilized nano-photocatalyst possess the merits of powder nano-photocatalyst. • The immobilized nano-photocatalyst adapts the requirement for clean and convenient manipulation. - Abstract: We developed an immobilized carbon nanotube (CNT)–titanium dioxide (TiO{sub 2}) heterostructure material for the photocatalytic oxidation of methyl orange in aqueous phase. The catalyst material was prepared via sol–gel method using multi-walled CNTs grown on graphite substrate as carriers. The multi-walled CNTs were synthesized from thermal decomposing of hydrocarbon gas directly on thin graphite plate, forming immobilized 3-dimensional network of CNTs. The nanophase TiO{sub 2} was synthesized coating on CNTs to form “coral”-shaped nanocomposite 3-dimensional network on graphite substrate, thus bringing effective porous structure and high specific surface area, and possessing the merit of dispersive powder photocatalysts, which is the fully available surface area, while adapting the requirement for clean and convenient manipulation as an immobilized photocatalyst. Moreover, the CNT–TiO{sub 2} heterostructure reduced the electron–hole pair recombination rate and enhanced the photoabsorption and the adsorption ability, resulting in elevating the photocatalysis efficiency. These synergistic effects due to the hybrid nature of the materials and interphase interaction greatly improved the catalytic activity, and demonstrated superior photocatalytic performances. Our work can be a significant inspiration for developing hybrid nano-phase materials to realize sophisticated functions, and bear tremendous significance for the development and applications of semiconductor nano-materials.

  7. Synthesis of amino-silane modified superparamagnetic Fe{sub 3}O{sub 4} nanoparticles and its application in immobilization of lipase from Pseudomonas fluorescens Lp1

    Energy Technology Data Exchange (ETDEWEB)

    Kanimozhi, S., E-mail: skanimo@gmail.com [Department of Biotechnology, Sathyabama University, Jeppiaar Nagar, Rajivgandhi Salai, Chennai 600119, Tamil Nadu (India); Perinbam, K. [Department of Plant Biology and Biotechnology, Nandanam Arts College (Men), Chennai 600035, Tamil Nadu (India)

    2013-05-15

    Highlights: ► Magnetic nanoparticles were synthesized by chemical co-precipitation method. ► Surface was functionalized with amino-silane and used for lipase immobilization. ► Characterized through TEM, SEM, XRD, FT-IR and VSM analysis. ► The functionalization and immobilization did not affect the magnetite properties. ► The immobilized lipase showed greater functional property than free lipase. - Abstract: Superparamagnetic nanoparticles (Fe{sub 3}O{sub 4}–magnetite) were prepared by chemical co-precipitation method and their surface was functionalized with 3-aminopropyltriethoxysilane via silanization reaction to obtain amino functionalized magnetic nanoparticles. The purified lipase from Pseudomonas fluorescens Lp1 was immobilized onto functionalized magnetite using glutaraldehyde as the coupling agent. The characterization of the nanoparticles was done by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, vibrating sample magnetometry and Fourier transformed infrared spectroscopy. The size of the magnetite was measured about 10–30 nm. The results of characterization study revealed the successful immobilization of lipase on to functionalized magnetite. The saturation magnetization of magnetic nanoparticles was found to be 28.34 emu/g whereas the immobilized magnetic nanoparticle was 17.074 emu/g. The immobilized lipase had greater activity at 50 °C and thermal stability upto 70 °C. It exhibited excellent reusability for 4 cycles and storage stability upto 15 days by retaining 75% of its initial activity.

  8. Synthesis of L-[{beta}-{sup 11}C]amino acids using immobilized enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Ikemoto, M.; Yada, T. [Ikeda Food Research Corporation, Minooki-cho, Fukuyama-shi, Hiroshima (Japan); Sasaki, M. [Sumitomo Heavy Industries, Kitashinagawa, Shinagawa-ku, Tokyo (Japan); Haradahira, T. [Division of Advanced Technology for Medical Imaging, National Institute of Radiological Sciences, Chiba (Japan); Omura, H.; Furuya, Y.; Watanabe, Y.; Suzuki, K. [Subfemtomole Biorecognition Project, Japan Science and Technology Corporation, Osaka (Japan)

    1999-04-01

    L-[{beta}-{sup 11}C]-3,4-dihydroxyphenylalanine(L-[{beta}-{sup 11}C]DOPA) and L-[{beta}-{sup 11}C]-5-hydroxytryptophan(L-[{beta}-{sup 11}C]-5-HTP) were synthesized in one step with immobilized thermostable enzymes (alanine racemase, D-amino acid oxidase, and {beta}-tyrosinase or tryptophanase) on an aminopropyl-CPG carrier in a single column and by passing D,L-[3-{sup 11}C]alanine through the column with coenzymes and other substrates. L-[{beta}-{sup 11}C]DOPA and L-[{beta}-{sup 11}C]-5-HTP could be obtained at yields of 53% and 60%, respectively, by optimizing the amounts and the ratios of the enzymes used, the reaction temperature, the pH, and the flow rate. Moreover, the same immobilized enzyme column could be used repeatedly.

  9. Immobilization of proteins onto microbeads using a DNA binding tag for enzymatic assays.

    Science.gov (United States)

    Kojima, Takaaki; Mizoguchi, Takuro; Ota, Eri; Hata, Jumpei; Homma, Keisuke; Zhu, Bo; Hitomi, Kiyotaka; Nakano, Hideo

    2016-02-01

    A novel DNA-binding protein tag, scCro-tag, which is a single-chain derivative of the bacteriophage lambda Cro repressor, has been developed to immobilize proteins of interest (POI) on a solid support through binding OR consensus DNA (ORC) that is tightly bound by the scCro protein. The scCro-tag successfully bound a transglutaminase 2 (TGase 2) substrate and manganese peroxidase (MnP) to microbeads via scaffolding DNA. The resulting protein-coated microbeads can be utilized for functional analysis of the enzymatic activity using flow cytometry. The quantity of bead-bound proteins can be enhanced by increasing the number of ORCs. In addition, proteins with the scCro-tag that were synthesized using a cell-free protein synthesis system were also immobilized onto the beads, thus indicating that this bead-based system would be applicable to high-throughput analysis of various enzymatic activities.

  10. Immobilization of enzyme (DAAO) on hybrid nanoporous MCF, SBA-15, and MCM-41 materials

    Science.gov (United States)

    Phi, Tien Q.; Le, Hy G.; Vu, Tuan A.; Phan, Thao T. H.; Pham, Huyen T.; Dao, Canh Duc; Dang, Phuong T.

    2011-12-01

    Hybrid nanoporous MCF, SBA-15 and MCM-41 materials were synthesized via hydrothermal treatment and functionalized with 3-aminopropyltriethoxysilane (APTES) via post-synthesis grafting and sequently activated by glutardialdehyde and then were used to immobilize D-amino acid oxidase (DAAO). The amino-functionalized materials were characterized by various techniques: XRD, IR and N2 adsorption-desorption (BET). From characterization results, it indicated that these materials still maintained their structure after functionalization. The data IR and TGA-DTA analysis demonstrated the incorpotation of amine functional groups on the surface of APTES-functionalized samples. The DAAO immobilized on functionalized materials exhibited higher catalytic activity and stability for conversion of cephalosporin C (CPC) compare to those of non-functionalized one. Further more, the catalytic activity as well as stability of enzyme decreased in order MCF > SBA-15 > MCM-41 with the decrease of their pore size.

  11. Optical Biosensor with Multienzyme System Immobilized onto Hybrid Membrane for Pesticides Determination

    Directory of Open Access Journals (Sweden)

    Lyubov Yotova

    2011-12-01

    Full Text Available A construction of optical biosensor based on simultaneous immobilization of acetylcholinesterase and choline oxidase enzymes for the detection of pesticides residues is described. Different kinds of novel SiO2 hybrid membranes were synthesized to be suitable for optical biosensors using sol-gel techniques. The bioactive component of the sensor consists of a multi-enzyme system including acetylcholinesterase and choline oxidase covalently immobilized on new hybrid membranes. The sensor exhibited a linear response to acetylcholine in a concentration range of 2.5 - 30 mM. Inhibition plots obtained from testing carbamate (carbofuran pesticides exhibited concentration dependent behaviour and showed linear profiles in concentration ranges between 5x10-8 - 5x10-7 M for carbofuran. The factors affecting the constructed optical biosensors were investigated.

  12. Hybrid Polymer-Immobilized Nanosized Pd Catalysts for Hydrogenation Reaction Obtained via Frontal Polymerization

    Directory of Open Access Journals (Sweden)

    Anatolii D. Pomogailo

    2013-01-01

    Full Text Available A new approach to the synthesis of mixed-type immobilized catalysts by frontal polymerization of metal-containing monomer in the presence of highly dispersed mineral support has been developed. Synthesis of the acrylamide Pd(II nitrate complex, Pd(CH2=CHCONH22 (NO32 (PdAAm, on the SiO2 (Al2O3, C surface and its consequent frontal polymerization and reduction lead to the formation of organic-inorganic composites with polymer-stabilized Pd nanoparticles. The immobilized metal complexes and palladium nanoparticles were characterized by various physical and chemical methods. The synthesized hybrid nanocomposites are efficient and selective catalysts for hydrogenation of cyclohexene, alkene, and acetylene alcohols, as well as di- and trinitrotoluene. Catalyst intermediates separated by nondestructive testing method have been described and changing in the palladium charge during the catalytic process has been identified.

  13. Fiber optic biosensor of immobilized firefly luciferase

    Institute of Scientific and Technical Information of China (English)

    蔡谨; 吉鑫松; 等

    2002-01-01

    Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B,The kinetic properties of immobilized luciferase were extensively studied.The Km' for D-luciferin is 11.9umol/L,the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25℃ respectively.A luminescence fiber optic biosensor,making use of immobilized crude luciferase was developed for assay of ATP.The peak light intensity was linear with respect to ATP concentration in range of 10-9-10-5mol/L.A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.

  14. Fiber optic biosensor of immobilized firefly luciferase

    Institute of Scientific and Technical Information of China (English)

    蔡谨; 孟文芳; 吉鑫松

    2002-01-01

    Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B. The kinetic properties of immobilized luciferase were extensively studied. The Km′ for D-luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25℃ respectively. A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak light intensity was linear with respect to ATP concentration in range of 10-9-10-5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal oxygen environments.

  15. Study on Growth and Optical, Scintillation Properties of Thallium Doped Cesium Iodide –Scintillator Crystal

    Directory of Open Access Journals (Sweden)

    B. Ravi

    2014-06-01

    Full Text Available Single crystal of Thallium doped cesium Iodide –Scintillator crystal was grown using vertical Bridgeman technique. The grown crystal was included for cutting and polishing for the characterization purpose and this crystal was studied by optical transmission properties, photo luminescence and thermally luminescence characteristics. Gamma-ray detectors were fabricated using the grown crystal that showed good linearity and nearly 7.5% resolution at 662 keV.

  16. Evaporative cooling of cesium atoms in the gravito-optical surface trap

    CERN Document Server

    Hammes, M; Grimm, R

    2000-01-01

    We report on cooling of an atomic cesium gas closely above an evanescent-wave. Our first evaporation experiments show a temperature reduction from 10muK down to 300nK along with a gain in phase-space density of almost two orders of magnitude. In a series of measurements of heating and spin depolarization an incoherent background of resonant photons in the evanescent-wave diode laser light was found to be the limiting factor at this stage.

  17. The effects of using Cesium-137 teletherapy sources as a radiological weapon (dirty bomb)

    OpenAIRE

    Liolios, Theodore

    2009-01-01

    While radioactive sources used in medical diagnosis do not pose a great security risk due to their low level of radioactivity, therapeutic sources are extremely radioactive and can presumably be used as a radiological weapon. Cobalt-60 and Cesium-137 sources are the most common ones used in radiotherapy with over 10,000 of such sources currently in use worldwide, especially in the developing world, which cannot afford modern accelerators. The present study uses computer simulations to investi...

  18. Strategic Design and Optimization of Inorganic Sorbents For Cesium, Strontium and Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.; Nyman, M.; Clearfield, A.; Maginn, E.

    2006-06-01

    The basic science goal in this project identifies structure/affinity relationships for selected radionuclides and existing sorbents. The task will apply this knowledge to the design and synthesis of new sorbents that will exhibit increased affinity for cesium, strontium and actinide separations. The target problem focuses on the treatment of high-level nuclear wastes. The general approach can likewise be applied to nonradioactive separations.

  19. Analysis of SubRamsey Patterns in Cesium Beam Frequency Standards

    Institute of Scientific and Technical Information of China (English)

    CHEN Jingbiao; WANG Fengzhi; YANG Donghai; WANG Yiqiu

    2001-01-01

    Using a precise probability expres-sion under excessive microwave power condition, theRamsey patterns in a cesium atomic beam frequencystandard with Ramsey separated oscillating fields havebeen carefully analyzed by numerical method. TwosubRamsey patterns are produced on both sides ofthe central Ramsey pattern. All factors, including mi-crowave power, excitation region length, drift regionlength and atomic velocity distribution, which affectthe subRamsey pattern have been analyzed, and someexplanations coming from approximated theory havebeen corrected in this paper.

  20. Prussian blue as an antidote for radioactive thallium and cesium poisoning

    Directory of Open Access Journals (Sweden)

    Altagracia-Martinez M

    2012-06-01

    Full Text Available Marina Altagracia-Martínez, Jaime Kravzov-Jinich, Juan Manuel Martínez-Núñez, Camilo Ríos-Castañeda, Francisco López-NaranjoDepartments of Biological Systems and Health Care, Biological and Health Sciences Division, Universidad Autónoma Metropolitana-Xochimilco, Mexico DF, MexicoBackground: Following the attacks on the US on September 11, 2001, potentially millions of people might experience contamination from radioactive metals. However, before the specter of such accidents arose, Prussian blue was known only as an investigational agent for accidental thallium and cesium poisoning. The purpose of this review is to update the state of the art concerning use of Prussian blue as an effective and safe drug against possible bioterrorism attacks and to disseminate medical information in order to contribute to the production of Prussian blue as a biodefense drug.Methods: We compiled articles from a systematic review conducted from January 1, 1960 to March 30, 2011. The electronic databases consulted were Medline, PubMed, the Cochrane Library, and Scopus.Results: Prussian blue is effective and safe for use against radioactive intoxications involving cesium-137 and thallium. The US Food and Drug Administration has approved Prussian blue as a drug, but there is only one manufacturer providing Prussian blue to the US. Based on the evidence, Prussian blue is effective for use against radioactive intoxications involving cesium-137 and thallium, but additional clinical research on and production of Prussian blue are needed.Keywords: Prussian blue, radioactive cesium, thallium, intoxication, biodefense drug

  1. Mössbauer study on the gamma radiolysis of anhydrous cesium tris (oxalato) ferrate(III)

    Science.gov (United States)

    Ladriere, J.; Senterre, V.; Apers, D.

    1992-04-01

    The final product of the gamma radiolysis of anhydrous cesium tris(oxalato) ferrate(III) has been identified by Mössbauer spectroscopy as Cs2Fe(ox)2. The radiolytic decomposition proceeds as a first-order process due to the original compound depletion and to the radiolytic stability of the ferrous compound. Lamb-Mössbauer factors measurements indicate that the recoilless fractions of the iron species are practically unaffected by the radiolysis.

  2. The Effect of Cesium Vapour on the Bulk Conductivity of Plasma - Sprayed Alumina

    Science.gov (United States)

    2007-11-02

    from the NaK coolant channels by a 50 [tm gap filled with helium at around 100 Torr. Ideally there would be no contact between the outer metallic ...reservoir of the liquid metal . The reservoir consists of a one inch diameter stainless steel cylinder clamped between two copper blocks. Cartridge heaters...Cesium is contained within the inter-electrode gap by a metal -ceramic seal at each end of the TFE. Therefore under normal operating conditions the

  3. Photon Driven Transformation of Cesium Lead Halide Perovskites from Few-Monolayer Nanoplatelets to Bulk Phase.

    Science.gov (United States)

    Wang, Yue; Li, Xiaoming; Sreejith, Sivaramapanicker; Cao, Fei; Wang, Zeng; Stuparu, Mihaiela Corina; Zeng, Haibo; Sun, Handong

    2016-12-01

    Influence of light exposure on cesium lead halide nanostructures has been explored. A discovery of photon driven transformation (PDT) in 2D CsPbBr3 nanoplatelets is reported, in which the quantum-confined few-monolayer nanoplatelets will convert to bulk phase under very low irradiation intensity (≈20 mW cm(-2) ). Benefiting from the remarkable emission color change during PDT, the multicolor luminescence photopatterns and facile information photo-encoding are established.

  4. Spatial variability and the fate of cesium in coastal sediments near Fukushima, Japan

    Directory of Open Access Journals (Sweden)

    E. Black

    2014-05-01

    Full Text Available Quantifying the amount of cesium incorporated into marine sediments as a result of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP accident has proven challenging due to the limited multi-core sampling from within the 30 km zone around the facility, the inherent spatial heterogeneities in ocean sediments, and the potential for inventory fluctuations due to physical, biological, and chemical processes. Using 210Pb, 234Th, 137Cs, and 134Cs profiles from 20 sediment cores, coastal sediment inventories were reevaluated. A minimum 137Cs sediment inventory of 100 ± 50 TBq was found for an area of 55 000 km2 using cores from this study and a total of 130 ± 60 TBq using an additional 181 samples. These inventories represent less than 1% of the estimated 15–30 PBq of cesium released during the FDNPP disaster and constitute ~ 90% of the total coastal inventory of 137Cs remaining in 2012. The time needed for surface sediment activities (0 to 3 cm at the 20 locations to reduce by 50% via bioturbation was estimated to range from 0.4 to 26 years, indicating a much greater persistence of cesium in the sediments relative to coastal water activities. However, due to the observed variability in mixing rates, grain size, and inventories, additional cores are needed to further improve estimates and capture the full extent of cesium penetration into the shallow coastal sediments, which was deeper than 14 cm for all cores retrieved from water depths less than 150 m.

  5. Physiologically driven avian vocal synthesizer

    Science.gov (United States)

    Sitt, Jacobo D.; Arneodo, Ezequiel M.; Goller, Franz; Mindlin, Gabriel B.

    2010-03-01

    In this work, we build an electronic syrinx, i.e., a programmable electronic device capable of integrating biomechanical model equations for the avian vocal organ in order to synthesize song. This vocal prosthesis is controlled by the bird’s neural instructions to respiratory and the syringeal motor systems, thus opening great potential for studying motor control and its modification by sensory feedback mechanisms. Furthermore, a well-functioning subject-controlled vocal prosthesis can lay the foundation for similar devices in humans and thus provide directly health-related data and procedures.

  6. Method of synthesizing tungsten nanoparticles

    Science.gov (United States)

    Thoma, Steven G; Anderson, Travis M

    2013-02-12

    A method to synthesize tungsten nanoparticles has been developed that enables synthesis of nanometer-scale, monodisperse particles that can be stabilized only by tetrahydrofuran. The method can be used at room temperature, is scalable, and the product concentrated by standard means. Since no additives or stabilizing surfactants are required, this method is particularly well suited for producing tungsten nanoparticles for dispersion in polymers. If complete dispersion is achieved due to the size of the nanoparticles, then the optical properties of the polymer can be largely maintained.

  7. Synthesized Optimization of Triangular Mesh

    Institute of Scientific and Technical Information of China (English)

    HU Wenqiang; YANG Wenyu

    2006-01-01

    Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.

  8. Coupled reactions of immobilized enzymes and immobilized substrates: clinical application as exemplified by amylase assay.

    Science.gov (United States)

    Barabino, R C; Gray, D N; Keyes, M H

    1978-08-01

    We described a partitioned enzyme-sensor system, which incorporates an immoblized substrate and three or more discrete immobilized enzymes. This instrument measures alpha-amylase activity by passing the solution containing alpha-amylase over a column packed with immobilized starch. The resulting oligosaccharides are successively exposed to a column or columns containing immobolized glucose oxidase, catalase, glucoamylase or maltase, and glucose oxidase. The resulting hydrogen peroxide is detected by a three-electrode amperometric cell. All immobilized reagents were immobilized on a particulate, porous alumina to allow rapid and constant flow rate. With use of less than optimum immobilized reagents, alpha-amylase activity has been measured from about 5 to 200 kU/liter with a 50 microliter sample size. Lack of sensitivity is predominantly attributable to the low activity and low stability of immobilized maltase and glucoamylase. We believe that a clinical test using this system is feasible and desirable because the immobilized reagent system should allow for testing of alpha-amylase with excellent precision, convenience to the operator, and low cost.

  9. Temperature and number evolution of cold cesium atoms inside a wall-coated glass cell

    Institute of Scientific and Technical Information of China (English)

    黄家强; 张建伟; 王时光; 王力军

    2015-01-01

    We report an experimental study on the temperature and number evolution of cold cesium atoms diffusively cooled inside a wall-coated glass cell by measuring the absorption profile of the 62S1/2 (F=4)→62P3/2(F0=5) transition line with a weak probe laser in the evolution process. We found that the temperature of the cold atoms first gradually decreases from 16 mK to 9 mK, and then rapidly increases. The number of cold atoms first declines slowly from 2.1 × 109 to 3.7 × 108 and then falls drastically. A theoretical model for the number evolution is built and includes the instantaneous temperature of the cold atoms and a fraction p, which represents the part of cold cesium atoms elastically reflected by the coated cell wall. The theory is overall in good agreement with the experimental result, and a nonzero value is obtained for the fraction p, which indicates that the cold cesium atoms are not all heated to the ambient temperature by a single collision with the coated cell wall. These results can provide helpful insight for precision measurements based on diffuse laser cooling.

  10. DFB-ridge laser diodes at 894 nm for Cesium atomic clocks

    Science.gov (United States)

    von Bandel, N.; Garcia, M.; Lecomte, M.; Larrue, A.; Robert, Y.; Vinet, E.; Driss, O.; Parrilaud, O.; Krakowski, M.; Gruet, F.; Matthey, R.; Mileti, G.

    2016-02-01

    Time and frequency applications are in need of high accuracy and high stability clocks. Optically pumped compact industrial Cesium atomic clocks are a promising approach that could satisfy these demands. However, the stability of these clocks relies, among others, on the performances of the laser diodes that are used. This issue has led the III-V Lab to commit to the European Euripides-LAMA project that aims to provide competitive compact optical Cesium clocks for ground applications. This work will provide key experience for further space technology qualification. III-V Lab is in charge of the design, fabrication and reliability of Distributed-Feedback diodes (DFB) at 894 nm (D1 line of Cesium) and 852 nm (D2 line). LTF-Unine is in charge of their spectral characterisation. The use of D1 line for pumping will provide simplified clock architecture compared to the D2 line pumping thanks to simpler atomic transitions and a larger spectral separation between lines in the 894 nm case. Also, D1 line pumping overcomes the issue of unpumped "idle states" that occur with D2 line. The modules should provide narrow linewidth (= 10 Hz and 109 Hz2/Hz @ f >= 10 Hz.

  11. Inhibition of sodium current by taurine magnesium coordination compound prevents cesium chloride-induced arrhythmias.

    Science.gov (United States)

    Yin, Yongqiang; Wen, Ke; Wu, Yanna; Kang, Yi; Lou, Jianshi

    2012-05-01

    The mechanism(s) by which taurine magnesium coordination compound (TMCC) inhibits experimental arrhythmias remains poorly understood. The purpose of this study was to observe the effects of TMCC against cesium chloride-induced arrhythmia in the rabbit heart and find whether the antiarrhythmic activity is related to inhibition of sodium current. Early afterdepolarization was induced by 1.5 mM cesium chloride (1 ml kg(-1)) through intravenous injection. The monophasic action potentials (MAP) and electrocardiograms were simultaneously recorded. The effect of TMCC on functional refractory periods (FRPs) in the left atrium was also observed in vitro. Arrhythmias onset was significantly retarded by TMCC. The number of ventricular premature contractions and incidence of monophasic ventricular tachycardia and polyphasic ventricular tachycardia in 10 min were decreased by TMCC. These effects can be abolished by veratridine (10 μg kg(-1)). MAP duration at 90% repolarization was significantly prolonged by TMCC, which can be prolonged even longer by veratridine (10 μg kg(-1)). In vitro experiments showed that FRPs was prolonged by TMCC which can be cancelled by veratridine (10 μg kg(-1)). TMCC prevents cesium chloride-induced arrhythmias, and inhibition of sodium current, in part, contributes to the antiarrhythmic effect of TMCC.

  12. Study on magnetic separation for decontamination of cesium contaminated soil by using superconducting magnet

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Susumu, E-mail: igarashi@qb.see.eng.osaka-u.ac.jp; Nomura, Naoki; Mishima, Fumihito; Akiyama, Yoko, E-mail: yoko-ak@see.eng.osaka-u.ac.jp

    2014-09-15

    Highlights: • The method for the soil decontamination by the superconducting magnet is proposed. • Magnetic separation of clay minerals was performed by HGMS. • Soil separation ratio was evaluated by quantitative analysis using XRD. • It is expected that HGMS can be applied to the actual soil decontamination. - Abstract: The accident of Fukushima Daiichi nuclear power plant caused the diffusion of radioactive cesium over the wide area. We examined the possibility of applying magnetic separation method using the superconducting magnet, which can process a large amount of the soil in high speed, to the soil decontamination and volume reduction of the radioactive cesium contaminated soil. Clay minerals are classified as 2:1 and 1:1 types by the difference of their layer structures, and these types of minerals are respectively paramagnetic and diamagnetic including some exception. It is known that most of the radioactive cesium is strongly adsorbed on the clay, especially on 2:1 type clay minerals. It is expected that the method which can separate only 2:1 type clay minerals selectively from the mixture clay minerals can enormously contribute to the volume reduction of the contaminated soil. In this study, the components in the clay before and after separation were evaluated to estimate the magnetic separation efficiency by using X-ray diffraction. From the results, the decontamination efficiency and the volume reduction ratio were estimated in order to examine the appropriate separation conditions for the practical decontamination of the soil.

  13. ION EXCHANGE MODELING FOR REMOVAL OF CESIUM FROM HANFORD WASTE USING SUPERLIG 644 RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, L

    2004-05-01

    The expected performance of a proposed ion exchange column using SuperLig{reg_sign} 644 resin for the removal of cesium from Hanford high level radioactive alkaline waste is discussed. This report represents a final report on the ability and knowledge with regard to modeling the Cesium-SuperLig{reg_sign} 644 resin ion exchange system. Only the loading phase of the cycle process is addressed within this report. Pertinent bench-scale column tests and batch equilibrium experiments are addressed. The methodology employed and sensitivity analyses are also included (i.e., existing methodology employed is referenced to prior developmental efforts while updated methodology is discussed). Pilot-scale testing is not assessed since no pilot-scale testing was available at the time of this report. Column performance predictions are made considering three selected feed compositions under nominal operating conditions. The sensitivity analyses provided help to identify key parameters that aid in resin procurement acceptance criteria. The methodology and application presented within this report reflect the expected behavior of SuperLig{reg_sign} 644 resin manufactured at the production-scale (i.e, 250 gallon batch size level). The primary objective of this work was, through modeling and verification based on experimental assessments, to predict the cesium removal performance of SuperLig{reg_sign} 644 resin for application in the RPP pretreatment facility.

  14. Novel application of nanozeolite for radioactive cesium removal from high-salt wastewater.

    Science.gov (United States)

    Lee, Keun-Young; Kim, Kwang-Wook; Park, Minsung; Kim, Jimin; Oh, Maengkyo; Lee, Eil-Hee; Chung, Dong-Yong; Moon, Jei-Kwon

    2016-05-15

    Finding a striking peculiarity of nanomaterials and evaluating its feasibility for practical use are interesting topics of research. We investigated the application of nanozeolite's outstanding reactivity for a rapid and effective method for radioactive cesium removal in the wastewater generated from nuclear power plant accident, as a new concept. Extremely fast removal of cesium, even without stirring, was achieved by the nanozeolite at efficiencies never observed with bulk materials. The nanozeolite reached an adsorption equilibrium state within 1 min. Cesium adsorption by nanozeolite was demonstrated at reaction rates of orders of magnitude higher than that of larger zeolite phases. This observation was strongly supported by the positive correlation between the rate constant ratio (k2,bulk/k2,nano) and the initial Cs concentrations with a correlation coefficient (R(2)) of 0.99. A potential drawback of a nanoadsorbent is the difficulty of particle settling and separation because of its high dispersivity in solution. However, our results also demonstrated that the nanozeolite could be easily precipitated from the high-salt solution with ferric flocculant. The flocculation index reached a steady state within 10 min. A series of our experimental results met the goal of rapid processing in the case of emergency by applying the well-suited nanozeolite adsorption and flocculation.

  15. Derivation of cesium-137 residual radioactive material guidelines for the Peek Street site, Schenectady, New York

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.; Nimmagadda, M.; Yu, C.

    1992-01-01

    Residual radioactive material guidelines for cesium-137 were derived for the Peek rk. The derivation was based on the requirement that the Street site in Schenectady, New York. The derivation was based on the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the Peek Street site should not exceed a dose of 100 mrem/yr following remedial action. The US Department of Energy (DOE) residual radioactive material guideline computer code, RESRAD was used in this evaluation. Three potential scenarios were considered for the site on the assumption that for a period of 1,000 years following remedial action, the site wig be utilized without radiological restrictions. The scenarios vary with regard to use of the site, time spent at the site, and sources of food consumed. Results indicate that the basic dose limit of 100 mrem/yr will not be exceeded for cesium-137 within 1,000 years, provided that the soil concentration of cesium-137 at the Peek Street site does not exceed the following levels: 98 pCi/g for Scenario A (industrial worker: the expected scenario), 240 pCi/g for Scenario B (recreationist: a plausible scenario), and 34 pCi/g for Scenario C (resident farmer ingesting food produced in the decontaminated area: a plausible scenario).

  16. Enhanced capacity and stability for the separation of cesium in electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Tawfic, A.F.; Dickson, S.E.; Kim, Y. [McMaster University, Hamilton, ON (Canada); Mekky, W. [AMEC NSS, Power and Process America, Toronto (Canada)

    2015-03-15

    Electrically switched ion exchange (ESIX) can be used to separate ionic contaminants from industrial wastewater, including that generated by the nuclear industry. The ESIX method involves sequential application of reduction and oxidation potentials to an ion exchange film to induce the respective loading and unloading of cesium. This technology is superior to conventional methods (e.g electrodialysis reversal or reverse osmosis) as it requires very little energy for ionic separation. In previous studies, ESIX films have demonstrated relatively low ion exchange capacities and limited film stabilities over repeated potential applications. In this study, the methodology for the deposition of electro-active films (nickel hexacyanoferrate) on nickel electrodes was modified to improve the ion exchange capacity for cesium removal using ESIX. Cyclic voltammetry was used to investigate the ion exchange capacity and stability. Scanning electron microscopy (SEM) was used to characterize the modified film surfaces. Additionally, the films were examined for the separation of cesium ions. This modified film preparation technique enhanced the ion exchange capacity and improves the film stability compared to previous methods for the deposition of ESIX films. (authors)

  17. WESF cesium capsule behavior at high temperature or during thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Tingey, G.L.; Gray, W.J.; Shippell, R.J.; Katayama, Y.B.

    1985-06-01

    Double-walled stainless steel (SS) capsules prepared for storage of radioactive /sup 137/Cs from defense waste are now being considered for use as sources for commercial irradiation. Cesium was recovered at B-plant from the high-level radioactive waste generated during processing of defense nuclear fuel. It was then purified, converted to the chloride form, and encapsulated at the Hanford Waste Encapsulation and Storage Facility (WESF). The molten cesium chloride salt was encapsulated by pouring it into the inner of two concentric SS cylinders. Each cylinder was fitted with a SS end cap that was welded in place by inert gas-tungsten arc welding. The capsule configuration and dimensions are shown in Figure 1. In a recent review of the safety of these capsules, Tingey, Wheelwright, and Lytle (1984) indicated that experimental studies were continuing to produce long-term corrosion data, to reaffirm capsule integrity during a 90-min fire where capsule temperatures reached 800/sup 0/C, to monitor mechanical properties as a function of time, and to assess the effects of thermal cycling due to periodic transfer of the capsules from a water storage pool to the air environment of an irradiator facility. This report covers results from tests that simulated the effects of the 90-min fire and from thermal cycling actual WESF cesium capsules for 3845 cycles over a period of six months. 11 refs., 39 figs., 9 tabs.

  18. Fabrication of stimuli-sensitive hydrogel for the removal of cesium

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hee-Man; Bong, Sang Bum; Park, Chan Woo; Lee, Kune Woo; Seo, Bum-Kyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The nuclear accident at the Fukushima Daiichi nuclear power station in 2011 released a huge quantity of radioactive contaminants into the environment.1 Among these, cesium Cs-137 is the most problematic contaminant due to its long half-life (30.2 years), and high-energy gamma ray (γ-ray) emissions. 2 Various surface including road, roof, house, building were contaminated with Cs-137. These coating materials have some problems and limitation such as toxic component, and lack of reusability of materials related to the cost. Thus, a more cost-effective and environmental friendly coating materials is still desired. 3 In the present study, the stimuli-sensitive hydrogel were fabricated for the removal of radioactive Cs from solid surface. We describe the morphology, structure, and physical property of these stimuli sensitive hydrogel. In addition, their ability to eliminate cesium was also evaluated. The smart hydrogel coating materials showed an excellent morphology change from the liquid to film by addition of Ca ion. Therefore, the stimuli-sensitive hydrogel demonstrated good potential for the treatment of contaminated surface for the removal of radioactive cesium.

  19. Uptake and transport of radioactive cesium and strontium into grapevines after leaf contamination

    Science.gov (United States)

    Zehnder, H. J.; Kopp, P.; Eikenberg, J.; Feller, U.; Oertli, J. J.

    1995-07-01

    From 1989 to 1993 the foliar uptake of radioactive strontium (Sr-85) and cesium (Cs-134) by selected leaves of grapevine plants and the subsequent redistribution within the plants was examined under controlled conditions in a greenhouse. The radionuclides were applied as chlorides. These plants were grown in large pots containing a mixture of local soil and peat. Plant and soil samples were analyzed throughout the growing season and also during the following vegetation period. Only traces of the applied radiostrontium were taken up by the leaves. This element was essentially not redistributed within the plants. In contrast, radiocesium was easily taken up through the leaf surface, transported to other plant parts and to some extent released from the roots into the soil. Cesium reaching the soil may interact with clay particles causing a very reduced availability for plants. Therefore the soil may act as a long-term sink for radiocesium. On the other hand, grape berries represent transient sinks. The cesium levels in the berries decreased again in a late phase of maturation, but the mechanisms causing this loss are not yet identified. During the second vegetation period, only a very minor proportion of the radiocesium taken up previously by the plants was present in the above ground parts.

  20. Kinetic and equilibrium studies of cesium adsorption on ceiling tiles from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Miah, Muhammed Yusuf [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, K1A 0H3 (Canada); Department of Applied Chemistry and Chemical Technology, Noakhali Science and Technology University (Bangladesh); Volchek, Konstantin, E-mail: Konstantin.Volchek@ec.gc.ca [Emergencies Science and Technology Section, Environment Canada, 335 River Road, Ottawa, Ontario, K1A 0H3 (Canada); Kuang, Wenxing [SAIC Canada, 335 River Road, Ottawa, Ontario, K1A 0H3 (Canada); Tezel, F. Handan [Department of Chemical and Biological Engineering, University of Ottawa, 161 Louis-Pasteur, Ottawa, Ontario, K1N 6N5 (Canada)

    2010-11-15

    A series of experiments were performed to quantify the adsorption of cesium on ceiling tiles as a representative of urban construction materials. Adsorption was carried out from solutions to mimic wet environmental conditions. Non-radioactive cesium chloride was used as a surrogate of the radioactive {sup 137}Cs. The experiments were performed in the range of initial cesium concentrations of 0.114-23.9 mg L{sup -1} at room temperature (21 deg. C) around three weeks. Solution samples were taken after set periods of time and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The quantity of adsorbed Cs was calculated by mass balance as a function of time. Two kinetic and three equilibrium models were employed to interpret the test results. Determination of kinetic parameters for adsorption was carried out using the first-order reaction model and the intra-particle diffusion model. Adsorption equilibrium was studied using Langmuir, Freundlich and three-parameter Langmuir-Freundlich adsorption isotherm models. A satisfactory correlation between the experimental and the predicted values was observed.

  1. Metal organic frameworks for enzyme immobilization in biofuel cells

    Science.gov (United States)

    Bodell, JaDee

    Interest in biofuel cells has been rapidly expanding as an ever-growing segment of the population gains access to electronic devices. The largest areas of growth for new populations using electronic devices are often in communities without electrical infrastructure. This lack of infrastructure in remote environments is one of the key driving factors behind the development of biofuel cells. Biofuel cells employ biological catalysts such as enzymes to catalyze oxidation and reduction reactions of select fuels to generate power. There are several benefits to using enzymes to catalyze reactions as compared to traditional fuel cells which use metal catalysts. First, enzymes are able to catalyze reactions at or near room temperature, whereas traditional metal catalysts are only efficient at very high temperatures. Second, biofuel cells can operate under mild pH conditions which is important for the eventual design of safe, commercially viable devices. Also, biofuel cells allow for implantable and flexible technologies. Finally, enzymes exhibit high selectivity and can be combined to fully oxidize or reduce the fuel which can generate several electrons from a single molecule of fuel, increasing the overall device efficiency. One of the main challenges which persist in biofuel cells is the instability of enzymes over time which tend to denature after hours or days. For a viable commercial biofuel cell to be produced, the stability of enzymes must be extended to months or years. Enzymes have been shown to have improved stability after being immobilized. The focus of this research was to find a metal organic framework (MOF) structure which could successfully immobilize enzymes while still allowing for electron transport to occur between the catalytic center of the enzyme and the electrode surface within a biofuel cell for power generation. Four MOF structures were successfully synthesized and were subsequently tested to determine the MOF's ability to immobilize the following

  2. Sulfated fucan as support for antibiotic immobilization

    OpenAIRE

    Araújo P.M.; Oliveira G.B.; Córdula C.R.; Leite E.L.; Carvalho Jr. L.B.; Silva M.P.C.

    2004-01-01

    Xylofucoglucuronan from Spatoglossum schröederi algae was tested as a support for antibiotic immobilization. The polysaccharide (20 mg in 6 ml) was first activated using carbodiimide, 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide methiodide (20 mg in 2 ml), under stirring for 1 h at 25ºC and pH from 4.5 to 5.0. After adjusting the pH to 8.0, either gentamicin or amikacin (62.5 mg in 1.25 ml) was then immobilized on this chemically modified polysaccharide with shaking for 24 h in a cold room....

  3. Green biosynthesis of floxuridine by immobilized microorganisms.

    Science.gov (United States)

    Rivero, Cintia W; Britos, Claudia N; Lozano, Mario E; Sinisterra, Jose V; Trelles, Jorge A

    2012-06-01

    This work describes an efficient, simple, and green bioprocess for obtaining 5-halogenated pyrimidine nucleosides from thymidine by transglycosylation using whole cells. Biosynthesis of 5-fluoro-2'-deoxyuridine (floxuridine) was achieved by free and immobilized Aeromonas salmonicida ATCC 27013 with an 80% and 65% conversion occurring in 1 h, respectively. The immobilized biocatalyst was stable for more than 4 months in storage conditions (4 °C) and could be reused at least 30 times without loss of its activity. This microorganism was able to biosynthesize 2.0 mg L(-1) min(-1) (60%) of 5-chloro-2'-deoxyuridine in 3 h. These halogenated pyrimidine 2'-deoxynucleosides are used as antitumoral agents.

  4. Enhancement of antibacterial properties of polyurethanes by chitosan and heparin immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Kara, Filiz [Department of Chemistry, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Aksoy, E. Ayse [Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Hacettepe University, 06100 Ankara (Turkey); Yuksekdag, Zehranur [Biotechnology Laboratory, Department of Biology, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Aksoy, Serpil [Department of Chemistry, Faculty of Science, Gazi University, 06500 Ankara (Turkey); Hasirci, Nesrin, E-mail: nhasirci@metu.edu.tr [BIOMATEN, Center of Excellence in Biomaterials and Tissue Engineering, Middle East Technical University, 06800 Ankara (Turkey); Department of Chemistry, Faculty of Arts and Sciences, Middle East Technical University, 06800 Ankara (Turkey)

    2015-12-01

    Graphical abstract: - Highlights: • Polyurethane elastomer was synthesized in medical purity. • Chitosan (CH) and heparin (Hep) were immobilized on polyurethane films. • Modification with CH and Hep increased hydrophilicity and surface free energy. • Immobilized films had high antibacterial activity against four bacteria. • Bacterial adhesion significantly decreased on the modified surfaces. - Abstract: Being antibacterial is a required property for the materials used in medical devices and instruments. Polyurethanes (PUs) are one class of polymers widely used in the production of devices that especially come in contact with blood (e.g. heart valves, blood vessels, vascular grafts and catheters). In this study, hexamethylene diisocyanate based polyurethanes (PUh) were synthesized and antibacterial and anti-adhesive properties were added by immobilizing chitosan (CH) and heparin (Hep) on the samples of PUh via a stepwise process. Chemistry and topography of the modified film samples (PUh-CH and PUh-CH-Hep) were examined by Fourier Transform Infrared Spectrophotometry-Attenuated Total Reflectance (FTIR-ATR), Electron Spectroscopy for Chemical Analysis (ESCA) and Atomic Force Microscopy (AFM), and surface free energy (SFE) values after each step were determined by goniometer. PUh-CH and PUh-CH-Hep samples were found to be antibacterial against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) (both Gram positive) and Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) (both Gram negative) bacteria, and bacterial adhesion results showed a significant decrease in the number of viable bacteria on both modified samples where PUh-CH-Hep was the most effective. The findings of this study show that polymeric surfaces can be effectively modified and converted to be antibacterial by chitosan and heparin immobilization, and presence of both chemicals enhance efficacy against bacteria.

  5. The effect of organic amendment on mobility of cesium in tropical soils - The effect of organic amendment on sorption mechanisms for cesium and cobalt in tropical soils

    Energy Technology Data Exchange (ETDEWEB)

    Wasserman, M.A.V.; Santos-Oliveira, R. [Instituto de Engenharia nuclear/CNEN. Rua Helio de Almeida, 75. Cidade Universitaria - Ilha do Fundao, Rio de Janeiro, RJ. CEP 21941-906 (Brazil); Garcia, R.J.L.; Ferreira, A.C.M.; Rochedo, E.R.R.; Sobrinho, G.A.N. [Instituto de Radioprotecao e Dosimetria/CNEN. Av. Salvador Allende s /no. Rio de Janeiro, RJ. CEP: 22780-160 (Brazil); Perez, D.V. [Centro Nacional de Pesquisa de Solos/EMBRAPA. R. Jardim Botanico, 1024.Rio de Janeiro, RJ, CEP: 22460-000 (Brazil); Wasserman, J.C. [dUFF Network of Environment and Sustainable Development (REMADS-UFF), University Federal Fluminense, Niteroi, RJ (Brazil)

    2014-07-01

    This work aimed to investigate the mechanisms involved in the sorption of {sup 137}Cs and {sup 60}Co as a function of the physico-chemical properties of some types of Brazilian soils and the changes on the behavior of these radionuclides due to changes in soil properties promoted by organic amendment. The experimental study was conducted in a controlled area, where pots containing different types of soils (Ferralsol, Nitisol and Histosol) and different doses of organic amendment (no amendment; 2 kg.m{sup -2} and 4 kg.m{sup -2}) were spiked with {sup 137}Cs and {sup 60}Co. The organic amendment used in this experiment was obtained in the Unit of Compost of the Organic Material of Pinheiral (RJ, Brazil), where the compost is made up from the leaves swept from the streets of the Pinheiral city. The mobility of these radionuclides in the soil was assessed through sequential chemical extraction and desorption studies as a function of pH. The bioavailability was evaluated through the effective absorption of radionuclide by root crops (Raphanus sativus, L). This study evidenced that the organic amendment plays an important role in the desorption processes of cobalt and cesium, reducing desorption of both nuclides beneath higher organic amendment dose. This behavior was observed in acid conditions as well in alkaline. However extreme acid conditions may mobilize both radionuclides, although cobalt mobility was shown to be more sensitive to low pH than cesium. (authors)

  6. Synthesis and application of a triazene-ferrocene modifier for immobilization and characterization of oligonucleotides at electrodes.

    Science.gov (United States)

    Hansen, Majken N; Farjami, Elaheh; Kristiansen, Martin; Clima, Lilia; Pedersen, Steen Uttrup; Daasbjerg, Kim; Ferapontova, Elena E; Gothelf, Kurt V

    2010-04-16

    A new DNA modifier containing triazene, ferrocene, and activated ester functionalities was synthesized and applied for electrochemical grafting and characterization of DNA at glassy carbon (GC) and gold electrodes. The modifier was synthesized from ferrocenecarboxylic acid by attaching a phenyltriazene derivative to one of the ferrocene Cp rings, while the other Cp ring containing the carboxylic acid was converted to an activated ester. The modifier was conjugated to an amine-modified DNA sequence. For immobilization of the conjugate at Au or GC electrodes, the triazene was activated by dimethyl sulfate for release of the diazonium salt. The salt was reductively converted to the aryl radical which was readily immobilized at the surface. DNA grafted onto electrodes exhibited remarkable hybridization properties, as detected through a reversible shift in the redox potential of the Fc redox label upon repeated hybridization/denaturation procedures with a complementary target DNA sequence. By using a methylene blue (MB) labeled target DNA sequence the hybridization could also be followed through the MB redox potential. Electrochemical studies demonstrated that grafting through the triazene modifier can successfully compete with existing protocols for DNA immobilization through the commonly used alkanethiol linkers and diazonium salts. Furthermore, the triazene modifier provides a practical one-step immobilization procedure.

  7. Information retrieval for ecological syntheses.

    Science.gov (United States)

    Bayliss, Helen R; Beyer, Fiona R

    2015-06-01

    Research syntheses are increasingly being conducted within the fields of ecology and environmental management. Information retrieval is crucial in any synthesis in identifying data for inclusion whilst potentially reducing biases in the dataset gathered, yet the nature of ecological information provides several challenges when compared with medicine that should be considered when planning and undertaking searches. We present ten recommendations for anyone considering undertaking information retrieval for ecological research syntheses that highlight the main differences with medicine and, if adopted, may help reduce biases in the dataset retrieved, increase search efficiency and improve reporting standards. They are as follows: (1) plan for information retrieval at an early stage, (2) identify and use sources of help, (3) clearly define the question to be addressed, (4) ensure that provisions for managing, recording and reporting the search are in place, (5) select an appropriate search type, (6) identify sources to be used, (7) identify limitations of the sources, (8) ensure that the search vocabulary is appropriate, (9) identify limits and filters that can help direct the search, and (10) test the strategy to ensure that it is realistic and manageable. These recommendations may be of value for other disciplines where search infrastructures are not yet sufficiently well developed.

  8. Design and surface immobilization of short anti-biofilm peptides.

    Science.gov (United States)

    Mishra, Biswajit; Lushnikova, Tamara; Golla, Radha M; Wang, Xiuqing; Wang, Guangshun

    2017-02-01

    Short antimicrobial peptides are essential to keep us healthy and their lasting potency can inspire the design of new types of antibiotics. This study reports the design of a family of eight-residue tryptophan-rich peptides (TetraF2W) obtained by converting the four phenylalanines in temporin-SHf to tryptophans. The temporin-SHf template was identified from the antimicrobial peptide database (http://aps.unmc.edu/AP). Remarkably, the double arginine variant (TetraF2W-RR) was more effective in killing methicillin-resistant Staphylococcus aureus (MRSA) USA300, but less cytotoxic to human skin HaCat and kidney HEK293 cells, than the lysine-containing dibasic combinations (KR, RK and KK). Killing kinetics and fluorescence spectroscopy suggest membrane targeting of TetraF2W-RR, making it more difficult for bacteria to develop resistance. Because established biofilms on medical devices are difficult to remove, we chose to covalently immobilize TetraF2W-RR onto the polyethylene terephthalate (PET) surface to prevent biofilm formation. The successful surface coating of the peptide is supported by FT-IR and XPS spectroscopies, chemical quantification, and antibacterial assays. This peptide-coated surface indeed prevented S. aureus biofilm formation with no cytotoxicity to human cells. In conclusion, TetraF2W-RR is a short Trp-rich peptide with demonstrated antimicrobial and anti-biofilm potency against MRSA in both the free and immobilized forms. Because these short peptides can be synthesized cost effectively, they may be developed into new antimicrobial agents or used as surface coating compounds.

  9. Improved Stabilities of Immobilized Glucoamylase on Functionalized Mesoporous Silica Synthesised using Decane as Swelling Agent

    Directory of Open Access Journals (Sweden)

    Reni George

    2013-06-01

    Full Text Available Ordered mesoporous silica, with high porosity was used to immobilize glucoamylase via adsorption and covalent binding. Immobilization of glucoamylase within mesoporous silica was successfully achieved, resulting in catalytically high efficiency during starch hydrolysis. In this study, mesoporous silica was functionalized by co-condensation of tetraethoxysilane (TEOS with organosilane (3-aminopropyl triethoxysilane (APTES in a wide range of molar ratios of APTES: TEOS in the presence of triblock copolymer P123 under acidic hydrothermal conditions. The prepared materials were characterized by Small angle XRD, Nitrogen adsorption – desorption and 29Si MAS solid state NMR. N2 desorption studies showed that pore size distribution decreases due to pore blockage after functionalization and enzyme immobilization. Small angle XRD and 29Si MAS NMR study reveals mesophase formation and Si environment of the materials. The main aim of our work was to study the catalytical activity, effect of pH, temperature storage stability and reusability of covalently bound glucoamylase on mesoporous silica support. The result shows that the stability of enzyme can be enhanced by immobilization.  © 2013 BCREC UNDIP. All rights reservedReceived: 3rd December 2012; Revised: 4th April 2013; Accepted: 20th April 2013[How to Cite: George, R., Gopinath, S., Sugunan, S. (2013. Improved Stabilities of Immobilized Glucoamyl-ase on Functionalized Mesoporous Silica Synthesized using Decane as Swelling Agent. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 70-76. (doi:10.9767/bcrec.8.1.4208.70-76][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4208.70-76] | View in  |

  10. Immobilization of nitrite oxidizing bacteria using biopolymeric chitosan media

    Institute of Scientific and Technical Information of China (English)

    Pranee Lertsutthiwong; Duangcheewan Boonpuak; Wiboonluk Pungrasmi; Sorawit Powtongsook

    2013-01-01

    The effects of chitosan characteristics including the degree of deacetylation,molecular weight,particle size,pH pretreatment and immobilization time on the immobilization of nitrite-oxidizing bacteria (NOB) on biopolymeric chitosan were investigated.Nitrite removal efficiency of immobilized NOB depended on the degree of deacetylation,particle size,pH pretreatment on the surface of chitosan and immobilization time.Scanning electron microscope characterization illustrated that the number of NOB cells attached to the surface of chitosan increased with an increment of immobilization time.The optimal condition for NOB immobilization on chitosan was achieved during a 24-hr immobilization period using chitosan with the degree of deacetylation larger than 80% and various particle size ranges between 1-5 mm at pH 6.5.In general,the NOB immobilized on chitosan flakes has a high potential to remove excess nitrite from wastewater and aquaculture systems.

  11. Element Partitioning in Glass-Ceramic Designed for Actinides Immobilization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Glass-ceramics were designed for immobilization of actinides. In order to immobilizing more wastes in the matrix and to develop the optimum formulation for the glass-ceramic, it is necessary to study the

  12. Fabrication of graphene oxide decorated with Fe3O4@SiO2 for immobilization of cellulase

    Science.gov (United States)

    Li, Yue; Wang, Xiang-Yu; Jiang, Xiao-Ping; Ye, Jing-Jing; Zhang, Ye-Wang; Zhang, Xiao-Yun

    2015-01-01

    Fe3O4@SiO2-graphene oxide (GO) composites were successfully fabricated by chemical binding of functional Fe3O4@SiO2 and GO and applied to immobilization of cellulase via covalent attachment. The prepared composites were further characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. Fe3O4 nanoparticles (NPs) were monodisperse spheres with a mean diameter of 17 ± 0.2 nm. The thickness of SiO2 layer was calculated as being 6.5 ± 0.2 nm. The size of Fe3O4@SiO2 NPs was 24 ± 0.3 nm, similar to that of Fe3O4@SiO2-NH2. Fe3O4@SiO2-GO composites were synthesized by linking of Fe3O4@SiO2-NH2 NPs to GO with the catalysis of EDC and NHS. The prepared composites were used for immobilization of cellulase. A high immobilization yield and efficiency of above 90 % were obtained after the optimization. The half-life of immobilized cellulase (722 min) was 3.34-fold higher than that of free enzyme (216 min) at 50 °C. Compared with the free cellulase, the optimal temperature of the immobilized enzyme was not changed; but the optimal pH was shifted from 5.0 to 4.0, and the thermal stability was enhanced. The immobilized cellulase could be easily separated and reused under magnetic field. These results strongly indicate that the cellulase immobilized onto the Fe3O4@SiO2-GO composite has potential applications in the production of bioethanol.

  13. Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

    Science.gov (United States)

    Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

    2016-09-01

    Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved.

  14. Immobilization of Yarrowia lipolytica lipase Ylip2 for the biocatalytic synthesis of phytosterol ester in a water activity controlled reactor.

    Science.gov (United States)

    Cui, Caixia; Guan, Nan; Xing, Chen; Chen, Biqiang; Tan, Tianwei

    2016-10-01

    In this work, phytosterol ester was synthesized using Yarrowia lipolytica lipase Ylip2 that had been immobilized on inorganic support in a solvent-free system and reacted in a computer-aided water activity controlled bioreactor. The immobilization of Ylip2 on celite led to a remarkable increase in the phytosterol conversion compared to that of free lipase. An investigation of the reaction conditions were oleic acid as the fatty acid variety, 10,000U/g substrate, and a temperature of 50°C for phytosterol ester synthesis. Controlling of the water activity at a set point was accomplished by the introduction of dry air through the reaction medium at a digital feedback controlled flow rate. For the esterification of phytosterol ester, a low (15%) water activity resulted in a considerable improvement in phytosterol conversion (91.1%) as well as a decreased reaction time (78h). Furthermore, Ylip2 lipase immobilized on celite retained 90% esterification activity for the synthesis of phytosterol oleate after reused 8 cycles, while free lipase was only viable for 5 batches with 90% esterification activity remained. Finally, the phytosterol oleate space time yield increased from 1.65g/L/h with free lipase to 2.53g/L/h with immobilized lipase. These results illustrate that the immobilized Yarrowia lipolytica lipase Ylip2 in a water activity controlled reactor has great potential for the application in phytosterol esters synthesis.

  15. Conceptual Design of a Simplified Skid-Mounted Caustic-Side Solvent Extraction Process for Removal of Cesium from Savannah Rive Site High-Level Waste

    Energy Technology Data Exchange (ETDEWEB)

    Birdwell, JR.J.F.

    2004-05-12

    This report presents the results of a conceptual design of a solvent extraction process for the selective removal of {sup 137}Cs from high-level radioactive waste currently stored in underground tanks at the U.S. Department of Energy's Savannah River Site (SRS). This study establishes the need for and feasibility of deploying a simplified version of the Caustic-Side Solvent Extraction (CSSX) process; cost/benefit ratios ranging from 33 to 55 strongly support the considered deployment. Based on projected compositions, 18 million gallons of dissolved salt cake waste has been identified as having {sup 137}Cs concentrations that are substantially lower than the worst-case design basis for the CSSX system that is to be deployed as part of the Salt Waste Processing Facility (SWPF) but that does not meet the waste acceptance criteria for immobilization as grout in the Saltstone Manufacturing and Disposal Facility at SRS. Absent deployment of an alternative cesium removal process, this material will require treatment in the SWPF CSSX system, even though the cesium decontamination factor required is far less than that provided by that system. A conceptual design of a CSSX processing system designed for rapid deployment and having reduced cesium decontamination factor capability has been performed. The proposed accelerated-deployment CSSX system (CSSX-A) has been designed to have a processing rate of 3 million gallons per year, assuming 90% availability. At a more conservative availability of 75% (reflecting the novelty of the process), the annual processing capacity is 2.5 million gallons. The primary component of the process is a 20-stage cascade of centrifugal solvent extraction contactors. The decontamination and concentration factors are 40 and 15, respectively. The solvent, scrub, strip, and wash solutions are to have the same compositions as those planned for the SWPF CSSX system. As in the SWPF CSSX system, the solvent and scrub flow rates are equal. The system

  16. Covalent immobilization of porcine pancreatic lipase on carboxyl-activated magnetic nanoparticles: Characterization and application for enzymatic inhibition assays

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuan-Ting [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Ren, Xiao-Yun [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); Liu, Yi-Ming [Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS 39217 (United States); Wei, Ying [Changzhi Medical College, Changzhi 046000 (China); Qing, Lin-Sen [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China); Liao, Xun, E-mail: liaoxun@cib.ac.cn [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041 (China)

    2014-05-01

    Using carboxyl functionalized silica-coated magnetic nanoparticles (MNPs) as carrier, a novel immobilized porcine pancreatic lipase (PPL) was prepared through the 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. Transmission electron microscopic images showed that the synthesized nanoparticles (Fe{sub 3}O{sub 4}–SiO{sub 2}) possessed three dimensional core–shell structures with an average diameter of ∼ 20 nm. The effective enzyme immobilization onto the nanocomposite was confirmed by atomic force microscopic (AFM) analysis. Results from Fourier-transform infrared spectroscopy (FT-IR), Bradford protein assay, and thermo-gravimetric analysis (TGA) indicated that PPL was covalently attached to the surface of magnetic nanoparticles with a PPL immobilization yield of 50 mg enzyme/g MNPs. Vibrating sample magnetometer (VSM) analysis revealed that the MNPs-PPL nanocomposite had a high saturation magnetization of 42.25 emu·g{sup −1}. The properties of the immobilized PPL were investigated in comparison with the free enzyme counterpart. Enzymatic activity, reusability, thermo-stability, and storage stability of the immobilized PPL were found significantly superior to those of the free one. The K{sub m} and the V{sub max} values (0.02 mM, 6.40 U·mg{sup −1} enzyme) indicated the enhanced activity of the immobilized PPL compared to those of the free enzyme (0.29 mM, 3.16 U·mg{sup −1} enzyme). Furthermore, at an elevated temperature of 70 °C, immobilized PPL retained 60% of its initial activity. The PPL-MNPs nanocomposite was applied in the enzyme inhibition assays using orlistat, and two natural products isolated from oolong tea (i.e., EGCG and EGC) as the test compounds. - Highlights: • Porcine pancreatic lipase was firstly covalently immobilized onto carboxylated MNPs. • Immobilized porcine pancreatic lipase (PPL) was characterized by various techniques. • MNPs-PPL showed higher activity

  17. TiO{sub 2} beads and TiO{sub 2}-chitosan beads for urease immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Ispirli Doğaç, Yasemin, E-mail: yispirli@mu.edu.tr; Deveci, İlyas, E-mail: ideveci@mu.edu.tr; Teke, Mustafa, E-mail: mteke@mu.edu.tr; Mercimek, Bedrettin, E-mail: bedrettinmercimek@mu.edu.tr

    2014-09-01

    The aim of the present study is to synthesize TiO{sub 2} beads for urease immobilization. Two different strategies were used to immobilize the urease on TiO{sub 2} beads. In the first method (A), urease enzyme was immobilized onto TiO{sub 2} beads by adsorption and then crosslinking. In the second method (B), TiO{sub 2} beads were coated with chitosan-urease mixture. To determine optimum conditions of immobilization, different parameters were investigated. The parameters of optimization were initial enzyme concentration (0.5; 1; 1.5; 2 mg/ml), alginate concentration (1; 2; 3%), glutaraldehyde concentration (1; 2; 3% v/v) and chitosan concentration (2; 3; 4 mg/ml). The optimum enzyme concentrations were determined as 1.5 mg/ml for A and 1.0 mg/ml for B. The other optimum conditions were found 2.0% (w/v) for alginate concentration (both A and B); 3.0 mg/ml for chitosan concentration (B) and 2.0% (v/v) for glutaraldehyde concentration (A). The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4–70 °C), pH stability (4.0-9.0), operational stability (0-230 min) and reusability (20 times) were investigated for characterization. The optimum temperatures were 30 °C (A), 40 °C (B) and 35 °C (soluble). The temperature profiles of the immobilized ureases were spread over a large area. The optimum pH values for the soluble urease and immobilized urease prepared by using methods (A) and (B) were found to be 7.5, 7.0, 7.0, respectively. The thermal stabilities of immobilized enzyme sets were studied and they maintained 50% activity at 65 °C. However, at this temperature free urease protected only 15% activity. - Highlights: • TiO{sub 2} and TiO{sub 2}-chitosan beads for urease immobilization have been prepared and characterized. • The beads used in this work are good matrices for the immobilization of urease. • The immobilized urease was shown to have good properties and stabilities (pH and thermal stability, operational

  18. Electrocatalytic O2 Reduction at a Bio-inspired Mononuclear Copper Phenolato Complex Immobilized on a Carbon Nanotube Electrode.

    Science.gov (United States)

    Gentil, Solène; Serre, Doti; Philouze, Christian; Holzinger, Michael; Thomas, Fabrice; Le Goff, Alan

    2016-02-12

    An original copper-phenolate complex, mimicking the active center of galactose oxidase, featuring a pyrene group was synthesized. Supramolecular pi-stacking allows its efficient and soft immobilization at the surface of a Multi-Walled Carbon Nanotube (MWCNT) electrode. This MWCNT-supported galactose oxidase model exhibits a 4 H(+)/4 e(-) electrocatalytic activity towards oxygen reduction at a redox potential of 0.60 V vs. RHE at pH 5.

  19. Asymmetric Syntheses Aided by Biocatalysts

    Institute of Scientific and Technical Information of China (English)

    陈沛然; 顾建新; 魏志亮; 韩世清; 李祖义; 林国强

    2003-01-01

    This article summarizes the achievements of the authors' group in the area of biocatalyst-catalyzed organic reactions in recent 10 years. A strain of Geotrichum sp. obtained by screeninu is capable of stereoselectlvely reducing a number of carbonyl compounds. In many cases, the stermghemistry is complementary with that obtained by baker' s yeast. Therefore, this microorganism provides a useful pathway to the preparation of alcohol eompounds with specific configurations. On the other hand, a nmmber of plant sourees have been screened for oxynitrilases and the hydrocyanation reactions of various arylcarboxalde-hydes have been investigated.A"micro-aqueous reaction system" was invented,by which a serles of novel optically active cyanohydrins were prepared.On this hasis,a high through-put comtimasous reaction system has been designed.This paper also deseribes examples of the syntheses of bio-active compounds by using the optieally active compounds obtained from the above mentioned catalytic reactions as precursors.

  20. Metal immobilization in soils using synthetic zeolites

    NARCIS (Netherlands)

    Osté, L.A.; Lexmond, T.M.; Riemsdijk, van W.H.

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type, fau

  1. Immobilized Ruthenium Catalyst for Carbon Dioxide Hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Ying Min YU; Jin Hua FEI; Yi Ping ZHANG; Xiao Ming ZHENG

    2006-01-01

    Three kinds of cross linked polystyrene resin (PS) supported ruthenium complexes were developed as catalysts for the synthesis of formic acid from carbon dioxide hydrogenation. Many factors, such as the functionalized supports, solvents and ligands, could influence their activities and reuse performances greatly. These immobilized catalysts also offer the industrial advantages such as easy separation.

  2. Phosphopeptide enrichment by immobilized metal affinity chromatography

    DEFF Research Database (Denmark)

    Thingholm, Tine E.; Larsen, Martin R.

    2016-01-01

    Immobilized metal affinity chromatography (IMAC) has been the method of choice for phosphopeptide enrichment prior to mass spectrometric analysis for many years and it is still used extensively in many laboratories. Using the affinity of negatively charged phosphate groups towards positively...

  3. Immobilization of horseradish peroxidase onto kaolin.

    Science.gov (United States)

    Šekuljica, Nataša Ž; Prlainović, Nevena Ž; Jovanović, Jelena R; Stefanović, Andrea B; Djokić, Veljko R; Mijin, Dušan Ž; Knežević-Jugović, Zorica D

    2016-03-01

    Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.

  4. Immobilization: A Revolution in Traditional Brewing

    Science.gov (United States)

    Virkajärvi, Ilkka; Linko, Matti

    In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

  5. PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.

    2010-09-22

    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  6. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    Science.gov (United States)

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  7. Preparation of Iminodiacetic Acid-Polyethylene Glycol for Immobilized Metal Ion Affinity Partitioning

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The synthesis route was investigated and optimized for the preparation of iminodiacetic acid polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phaze systems. IDA PEG was synthesized from PEG in two steps by the reaction of iminodiacetic acid with a monosubetituted derivative of epichlorohydrin-activated PEG. The Cu2+ content combined with IDA-PEG was determined by atomic absorp tion spectrometry as 0.5 mol.mol-1 (PEG). Furthermore, the affinity partitioning behavior of lactate dehydrogenase in polyethylene glycol/hydroxypropyl starch aqueous two-phaze systems was studied to clarify the affinity effect of the Cu(Ⅱ)-IDA-PEG.

  8. Preparation of Layered Double Hydroxide-Immobilized Lipase for High Yield and Optically Active (-)-Menthyl butyrate

    Institute of Scientific and Technical Information of China (English)

    Siti; Salhah; Othman; Mahiran; Basri; Mohd.Zobir; Hussein; Mohd; Basyaruddin; Abdul; Rahman; Raja; Noor; Zaliha; Raja; Abdul; Rahman; Abu; Bakar; Salleh; Salina; Mat; Radzi; Azwani; Sofia; Ahmad; Khiar

    2007-01-01

    1 Results Layered Double Hydroxide (LDH) finds extensive usage in the areas of pharmaceutical sciences and catalysis. In this study, a member of the LDH family, Mg/Al-hydrotalcite (HT), or the so-called anionic clay, was prepared at ratio 4 (HT) by co-precipitating through continuous agitation. X-ray diffraction pattern and thermogravimetric analysis of the material indicated that a pure HT had been successfully synthesized. This matrix was then used as support in the immobilization of lipase from Cand...

  9. Synthesis of SrTiO3 for immobilization of simulated HLW by SHS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Strontium titanate synroc samples were synthesized by self-propagating high-temperature synthesis (SHS). Sr directly took part in the synthesis process. As a result, the loading content issue is basically resolved. The products were characterized by density, microhardness X-ray diffraction, and scanning electron microscopy (SEM/EDS). The leaching rate was measured by the method of PCT (product consistency test). The results indicate that the Sr2+-SrTiO3 compound is of high density, low leach rate and high stability and the synthesis process is feasible in technology and economy. It can be concluded that the strontium titanate synroc is a perfect material to immobilize HLW.

  10. A study of mechanisms responsible for incorporation of cesium and radiocesium into fruitbodies of king oyster mushroom (Pleurotus eryngii)

    Energy Technology Data Exchange (ETDEWEB)

    Bystrzejewska-Piotrowska, Grazyna [Isotope Laboratory, Faculty of Biology, Warsaw University, 02-096 Warsaw, Miecznikowa 1 (Poland)], E-mail: byst@biol.uw.edu.pl; Bazala, Michal A. [Isotope Laboratory, Faculty of Biology, Warsaw University, 02-096 Warsaw, Miecznikowa 1 (Poland)

    2008-07-15

    Ex vitro cultures of Pleurotus eryngii were carried out under controlled conditions using sterile medium composed of barley seeds. The influence of alkali and alkaline earth element salts (CsCl, KCl, NaCl, RbCl, and CaCl{sub 2}) and tetraethylammonium chloride on incorporation of cesium, potassium, sodium, rubidium and calcium, and their distribution within fruitbodies, was examined. The results show that incorporation of cesium into fruitbodies was not suppressed by Na{sup +} and Rb{sup +} or tetraethylammonium chloride. However, it was inhibited by Ca{sup 2+} and stimulated by high concentrations of K{sup +}. The inhibition of cesium incorporation by Ca{sup 2+}, lack of influence of tetraethylammonium chloride and stimulation by high K{sup +} concentrations suggest that there may exist two pathways of passive transport of cesium in mycelium: (i) uptake mediated by a non-specific potassium channel localised in plasmalemma (similar to voltage-insensitive cation channel, VICC) followed by diffusive transport inside hyphae and (ii) extracellular transport from the medium through inter-hyphal cavities into fruitbodies. The results highlight distinctiveness of mechanisms responsible for the uptake and incorporation of cesium in mushrooms and plants.

  11. Reactions of nitroxides 15. Cinnamates bearing a nitroxyl moiety synthesized using a Mizoroki–Heck cross-coupling reaction

    Directory of Open Access Journals (Sweden)

    Jerzy Zakrzewski

    2015-07-01

    Full Text Available Cinnamic acid derivatives bearing a nitroxyl moiety (2,2,6,6-tetramethyl-1-oxyl-4-piperidyl 3-E-aryl acrylates were synthesized in 30–100% yield using a Mizoroki–Heck cross-coupling reaction between 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl and iodobenzene derivatives in the presence of palladium(II acetate coordinated with a tri(o-tolylphosphine ligand immobilized in a polyurea matrix.

  12. Synthese de champs sonores adaptative

    Science.gov (United States)

    Gauthier, Philippe-Aubert

    La reproduction de champs acoustiques est une approche physique au probleme technologique de la spatialisation sonore. Cette these concerne l'aspect physique de la reproduction de champs acoustiques. L'objectif principal est l'amelioration de la reproduction de champs acoustiques par "synthese de champs acoustiques" ("Wave Field Synthesis", WFS), une approche connue, basee sur des hypotheses de champ libre, a l'aide du controle actif par l'ajout de capteurs de l'erreur de reproduction et d'une boucle fermee. Un premier chapitre technique (chapitre 4) expose les resultats d'appreciation objective de la WFS par simulations et mesures experimentales. L'effet indesirable de la salle de reproduction sur les qualites objectives de la WFS fut illustre. Une premiere question de recherche fut ensuite abordee (chapitre 5), a savoir s'il est possible de reproduire des champs progressifs en salle dans un paradigme physique de controle actif: cette possibilite fut prouvee. L'approche technique privilegiee, "synthese de champs adaptative" ("Adaptive Wave Field Synthesis" [AWFS]), fut definie, puis simulee (chapitre 6). Cette approche d'AWFS comporte une originalite en controle actif et en reproduction de champs acoustiques: la fonction cout quadratique representant la minimisation des erreurs de reproduction inclut une regularisation de Tikhonov avec solution a priori qui vient de la WFS. L'etude de l'AWFS a l'aide de la decomposition en valeurs singulieres (chapitre 7) a permis de comprendre les mecanismes propres a l'AWFS. C'est la deuxieme principale originalite de la these. L'algorithme FXLMS (LMS et reference filtree) est modifie pour l'AWFS (chapitre 8). Le decouplage du systeme par decomposition en valeurs singulieres est illustre dans le domaine du traitement de signal et l'AWFS basee sur le controle independant des modes de rayonnement est simulee (chapitre 8). Ce qui constitue la troisieme originalite principale de cette these. Ces simulations du traitement de signal

  13. Development of sealed radioactive sources immobilized in epoxy resin for verification of detectors used in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Tiezzi, Rodrigo; Rostelato, Maria Elisa C.M.; Nagatomi, Helio R.; Zeituni, Calos A.; Benega, Marcos A.G.; Souza, Daiane B. de; Costa, Osvaldo L. da; Souza, Carla D.; Rodrigues, Bruna T.; Souza, Anderson S. de; Peleias Junior, Fernando S.; Santos, Rafael Melo dos; Melo, Emerson Ronaldo de, E-mail: rktiezzi@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Karan Junior, Dib [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

    2015-07-01

    The radioactive sealed sources are used in verification ionization chamber detectors, which measure the activity of radioisotopes used in several areas, such as in nuclear medicine. The measurement of the activity of radioisotopes must be made with accuracy, because it is administered to a patient. To ensure the proper functioning of the ionization chamber detectors, standardized tests are set by the International Atomic Energy Agency (IAEA) and the National Nuclear Energy Commission using sealed radioactive sources of Barium-133, Cesium-137 and Cobalt-57. The tests assess the accuracy, precision, reproducibility and linearity of response of the equipment. The focus of this work was the study and the development of these radioactive sources with standard Barium-133, Cesium-137 and Cobalt-57,using a polymer, in case commercial epoxy resin of diglycidyl ether of bisphenol A (DGEBA) and a curing agent based on modified polyamine diethylenetriamine (DETA), to immobilize the radioactive material. The polymeric matrix has the main function of fix and immobilize the radioactive contents not allowing them to leak within the technical limits required by the standards of radiological protection in the category of characteristics of a sealed source and additionally have the ability to retain the emanation of any gases that may be formed during the manufacture process and the useful life of this artifact. The manufacturing process of a sealed source standard consists of the potting ,into bottle standardized geometry, in fixed volume of a quantity of a polymeric matrix within which is added and dispersed homogeneously to need and exact amount in activity of the radioactive materials standards. Accordingly, a study was conducted for the choice of epoxy resin, analyzing its characteristics and properties. Studies and tests were performed, examining the maximum solubility of the resin in water (acidic solution, simulating the conditions of radioactive solution), loss of mechanical

  14. Removal of phosphate from aqueous solution by zeolite synthesized from fly ash.

    Science.gov (United States)

    Chen, Jiangang; Kong, Hainan; Wu, Deyi; Hu, Zhanbo; Wang, Zaosheng; Wang, Yanhua

    2006-08-15

    Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.6 times) following the synthesis process. Fractionation of immobilized phosphorus indicated that Fe+Al-P increased most significantly and consistently among all the phosphorus fractions following the conversion of fly ash to zeolite. The PIC and Ca+Mg-P were closely related to Ca content (with r values of 0.9683 and 0.9651, respectively) rather than Mg content (with r values of 0.3920 and 0.3212, respectively). The r values of PIC and Fe+Al-P with Fe content (with r values of 0.4686 and 0.6385, respectively) were higher than those with Al content (with r values of -0.7857 and -0.3770, respectively). Although calcium and iron components were mainly involved in phosphate immobilization, there was no significant change of Ca and Fe content following the conversion of fly ash to zeolite. Increase in dissociated Fe(2)O(3) and specific surface area probably accounted for the enhancement in PIC of synthesized zeolites compared with corresponding fly ashes. The PIC value of zeolites showed a significant correlation with dissociated Fe(2)O(3) (r=0.6186). The specific surface area increased 26.0-89.4 times as a result of the conversion of fly ash to zeolite. The maximum removal of phosphate occurred within different pH ranges for zeolites which were synthesized from high, medium and low calcium fly ashes and this behavior was explained by the reaction of phosphate with calcium and iron components.

  15. Cesium accumulation by bacterium Thermus sp.TibetanG7: hints for biomineralization of cesiumbearing geyserite in hot springs in Tibet, China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, China, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K+, Na+ and K+-regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K+ and Na+, the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41 μmol Cesium/g cell dry weight in Na+ and K+ inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K+-deficient cells showed a much higher capacity of cesium accumulation compared with K+-sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.

  16. Principles, techniques, and applications of biocatalyst immobilization for industrial application.

    Science.gov (United States)

    Eş, Ismail; Vieira, José Daniel Gonçalves; Amaral, André Corrêa

    2015-03-01

    Immobilization is one of the most effective and powerful tools used in industry, which has been studied and improved since the last century. Various immobilization techniques and support materials have been used on both laboratory and industrial scale. Each immobilization technique is applicable for a specific production mostly depending on the cost and sensibility of process. Compared to free biocatalyst systems, immobilization techniques often offer better stability, increased activity and selectivity, higher resistance, improved separation and purification, reuse of enzymes, and consequently more efficient process. Recently, many reviews have been published about immobilization systems; however, most of them have focused on a specific application or not emphasized in details. This review focuses on most commonly used techniques in industry with many recent applications including using bioreactor systems for industrial production. It is also aimed to emphasize the advantages and disadvantages of the immobilization techniques and how these systems improve process productivity compared to non-immobilized systems.

  17. Screening of supports for immobilization of commercial porcine pancreatic lipase

    Directory of Open Access Journals (Sweden)

    Robison Scherer

    2011-12-01

    Full Text Available The aim of this work is to report the performance of different supports for the immobilization of commercial porcine pancreatic lipase. The immobilization tests were carried out in several types of Accurel, activated alumina, kaolin, montmorillonite, ion exchange resins and zeolites. The characterization of the supports showed differences in terms of specific area and morphology. The characteristics of the supports influenced the amount of enzyme adsorbed, yield of immobilization and esterification activity of the resulting immobilized catalyst. The clays KSF and natural and pillared montmorillonites presented potential for use as support for lipase immobilization in terms of yield and esterification activity. Yields of immobilization of 76.32 and 52.01% were achieved for clays KSF and natural montmorillonite, respectively. Esterification activities of 754.03, 595.51, 591.88 and 515.71 U.g-1 were obtained for lipases immobilized in Accurel MP-100, Amberlite XAD-2, mordenite and pillared montmorillonite, respectively.

  18. FUNCTIONAL POLYHYDROXYALKANOATES SYNTHESIZED BY MICROORGANISMS

    Institute of Scientific and Technical Information of China (English)

    Guo-qiang Chen; Qiong Wu; Kai Zhao; Peter H.Yu

    2000-01-01

    Many bacteria have been found to synthesize a family of polyesters termed polyhydroxyalkanoate, abbreviated as PHA. Some interesting physical properties of PHAs such as piezoelectricity, non-linear optical activity, biocompatibility and biodegradability offer promising applications in areas such as degradable packaging, tissue engineering and drug delivery.Over 90 PHAs with various structure variations have been reported and the number is still increasing. The mechanical property of PHAs changes from brittle to flexible to elastic, depending on the side-chainlength of PHA. Many attempts have been made to produce PHAs as biodegradable plastics using various microorganisms obtained from screening natural environments, genetic engineering and mutation. Due to the high production cost, PHAs still can not compete with the nondegradable plastics, such as polyethylene and polypropylene. Various processes have been developed using low cost raw materials for fermentation and an inorganic extraction process for PHA purification. However, a super PHA production strain may play the most critical role for any large-scale PHA production. Our recent study showed that PHA synthesis is a common phenomenon among bacteria inhabiting various locations, especially oil-contaminated soils. This is very important for finding a suitable bacterial strain for PHA production. In fact, PHA production strains capable of rapid growth and rapid PHA synthesis on cheap molasses substrate have been found on molasses contaminated soils. A combination of novel properties and lower cost will allow easier commercialization of PHA for many applications.

  19. Immobilized silver nanoparticles enhance contact killing and show highest efficacy: elucidation of the mechanism of bactericidal action of silver

    Science.gov (United States)

    Agnihotri, Shekhar; Mukherji, Soumyo; Mukherji, Suparna

    2013-07-01

    NPs, as well as a higher concentration of silver ions in solution. In addition, the AgNP immobilized substrate was used multiple times with good efficacy, indicating this immobilization protocol is effective for retaining AgNPs while maintaining their disinfection potential. The antibacterial surface was found to be extremely stable in aqueous medium and no significant leaching (~1.15% of total silver deposited) of the AgNPs was observed. Thus, immobilization of AgNPs on a surface may promote reuse, reduce environmental risks associated with leaching of AgNPs and enhance cost effectiveness. Electronic supplementary information (ESI) available: Photographic image of silanization chamber; FEG-TEM image to show particle distribution of as-synthesized silver nanoparticles; photographic image of pristine amino-silanized glass and AgNPs immobilized glass; batch reactor fabrication for disinfection and silver release studies; surface coverage of silver nanoparticle immobilized glass substrate; and EDX analysis of the treated bacterial (E. coli) cells. See DOI: 10.1039/c3nr00024a

  20. Cesium Platinide Hydride 4Cs 2 Pt-CsH: An Intermetallic Double Salt Featuring Metal Anions

    Energy Technology Data Exchange (ETDEWEB)

    Smetana, Volodymyr [Ames Laboratory, US Department of Energy, and Critical Materials Institute, Ames Iowa 50011-3020 USA; Mudring, Anja-Verena [Ames Laboratory, US Department of Energy, and Critical Materials Institute, Ames Iowa 50011-3020 USA; Department of Materials Sciences and Engineering, Iowa State University, Ames Iowa 50011-3111 USA

    2016-10-24

    With Cs9Pt4H a new representative of ionic compounds featuring metal anions can be added to this rare-membered family. Cs9Pt4H exhibits a complex crystal structure containing Cs+ cations, Pt2- and H- anions. Being a red, transparent compound its band gap is in the visible range of the electromagnetic spectrum and the ionic type of bonding is confirmed by quantum chemical calculations. This cesium platinide hydride can formally be considered as a double salt of the “alloy” cesium–platinum, or better cesium platinide, Cs2Pt, and the salt cesium hydride CsH according to Cs9Pt4H≡4 Cs2Pt∙CsH.

  1. Prussian blue caged in alginate/calcium beads as adsorbents for removal of cesium ions from contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Vipin, Adavan Kiliyankil; Hu, Baiyang; Fugetsu, Bunshi, E-mail: hu@ees.hokudai.ac.jp

    2013-08-15

    Highlights: • Prussian blue was encapsulated in calcium/alginate beads. •The Prussian blue encapsulated beads were reinforced using carbon nanotubes. • Adsorption behaviors toward cesium were studied with the aid of appropriate mathematical models. • The beads showed high efficiency over a wide range of pH, potassium and sodium ion concentrations. • Continuous column analysis proved that the beads are suitable for large-scale water treatments. -- Abstract: Prussian blue encapsulated in alginate beads reinforced with highly dispersed carbon nanotubes were prepared for the safe removal of cesium ions from aqueous solutions. Equilibrium and kinetic studies were conducted using different models and the goodness of mathematical fitting of the experimental data on the adsorption isotherms was in the order Langmuir > Freundlich, and that of the kinetic models were in the order of pseudo second order > pseudo first order. Fixed bed adsorption column analysis indicated that the beads can be used for large scale treatment of cesium contaminated water.

  2. The role of cesium suboxides in low-work-function surface layers studied by X-ray photoelectron spectroscopy - Ag-O-Cs

    Science.gov (United States)

    Yang, S.-J.; Bates, C. W., Jr.

    1980-01-01

    The oxidation of cesium on silver substrates has been studied using photoyield measurements and X-ray photoelectron spectroscopy. The occurrence of two O1s peaks in the core-level spectrum at 527.5 and 531.5-eV binding energy for cesium and oxygen exposures giving the optimum photoyield proves that two oxides of cesium exist in high-photoyield surfaces, and not Cs2O alone as previously thought. From the shape and position of the cesium peaks and the Auger parameter, the assignment of the O1s peaks at 527.5- and 531.5-eV binding energies to oxygen in Cs2O and Cs11O3, respectively, can be made. Hence the total cesium-oxygen layer is a mixed phase consisting of Cs2O + Cs11O3, approximately 20-40 A thick.

  3. Effect of surface modification of low cost mesoporous SiO2 carriers on the properties of immobilized lipase.

    Science.gov (United States)

    Zou, Bin; Hu, Yi; Cui, Fengjie; Jiang, Ling; Yu, Dinghua; Huang, He

    2014-03-01

    To investigate the surface effects of low cost mesoporous SiO2 on the properties of lipase, a series of modified mesoporous SiO2 was synthesized through various alkoxysilanes reacted with hydroxyl of SiO2 (C1-SiO2, C8-SiO2, C16-SiO2, SH-SiO2, Ph-SiO2, NH2-SiO2). Particularly, ionic liquids as novel alkoxysilane were synthesized and subjected to modify the low cost mesoporous SiO2 (CH3IL-SiO2 and COOHIL-SiO2). The porcine pancreas lipase (PPL) was immobilized on the prepared materials. The activity assay indicated that the activation of enzymatic activity site was benefit from the longer alkyl chain of alkoxysilane because of the growing hydrophobic nature. Nevertheless, the loading of lipase decreased from 69% for PPL-C1-SiO2 to 59% for PPL-C16-SiO2, reflecting the growing hydrophobic property limited the immobilization yield. The characteristic of alkoxysilane group (SH-SiO2, Ph-SiO2, NH2-SiO2) was another important factor to influence immobilization efficiency and enzymatic performance besides the alkyl chain length. The immobilization efficiency of PPL-SH-SiO2, PPL-Ph-SiO2 and PPL-NH2-SiO2 maintained at least 93%. Compared with conventional alkoxysilane, the activity of PPL-CH3IL-SiO2 improved to 2.60 folds of PPL-SiO2. The immobilization efficiency of PPL-COOHIL-SiO2 was up to 97% and the relative activity was above 62% after five recycles.

  4. Preparation of photoreactive phospholipid polymer nanoparticles to immobilize and release protein by photoirradiation.

    Science.gov (United States)

    Chen, Weixin; Inoue, Yuuki; Ishihara, Kazuhiko

    2015-11-01

    Photoreactive and cytocompatible polymer nanoparticles for immobilizing and releasing proteins were prepared. A water-soluble and amphiphilic phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)-co-4-(4-(1-methacryloyloxyethyl)-2-methoxy-5-nitrophenoxy) butyric acid (PL)) (PMB-PL) was synthesized. The PMB-PL underwent a cleavage reaction at the PL unit with photoirradiation at a wavelength of 365 nm. Additionally, the PMB-PL took polymer aggregate in aqueous medium and was used to modify the surface of biodegradable poly(L-lactic acid) (PLA) nanoparticle as an emulsifier. The morphology of the PMB-PL/PLA nanoparticle was spherical and approximately 130 nm in diameter. The carboxylic acid group in the PL unit could immobilize proteins by covalent bonding. The bound proteins were released by a photoinduced cleavage reaction. Within 60s, up to 90% of the immobilized proteins was released by photoirradiation. From these results and with an understanding of the fundamental properties of MPC polymers, we concluded that PMB-PL/PLA nanoparticles have the potential to be used as smart carriers to deliver proteins to biological systems, such as the inside of living cells.

  5. Hydrophilic polydopamine-coated magnetic graphene nanocomposites for highly efficient tryptic immobilization.

    Science.gov (United States)

    Shi, Chenyi; Deng, Chunhui; Li, Yan; Zhang, Xiangmin; Yang, Pengyuan

    2014-06-01

    In this work, polydopamine-coated magnetic graphene (MG@PDA) nanocomposites were synthesized by a facile method. Trypsin was then directly immobilized on the surface of the nanocomposites through simple PDA chemistry with no need for introducing any other coupling groups. The as-made MG@PDA nanocomposites inherit not only the large surface area of graphene which makes them capable of immobilizing high amount of trypsin (up to 0.175 mg/mg), but also the good hydrophilicity of PDA which greatly improves their biocompatibility. Moreover, the strong magnetic responsibility makes them easy to be separated from the digested peptide solution when applying a magnetic field. The feasibility of the trypsin-immobilized MG@PDA (MG@PDA-trypsin) nanocomposites for protein digestion was investigated and the results indicated their high digestion efficiency in a short digestion time (10 min). In addition, the reusability and stability of the MG@PDA-trypsin nanocomposites were also tested in our work. To further confirm the efficiency of MG@PDA-trypsin nanocomposites for proteome analysis, they were applied to digest proteins extracted from skimmed milk, followed by nano RPLC-ESI-MS/MS analysis, and a total of 321 proteins were identified, much more than those obtained by 16-h in-solution digestion (264 proteins), indicating the great potential of MG@PDA-trypsin nanocomposites as the supports for high-throughput proteome study.

  6. Improved Performance of Lipase Immobilized on Tannic Acid-Templated Mesoporous Silica Nanoparticles.

    Science.gov (United States)

    Jiang, Yanjun; Sun, Wenya; Zhou, Liya; Ma, Li; He, Ying; Gao, Jing

    2016-08-01

    Mesoporous silica nanoparticles were synthesized by using tannic acid as a pore-forming agent, which is an environmentally friendly, cheap, and non-surfactant template. SEM and TEM images indicated that the tannic acid-templated mesoporous silica nanoparticles (TA-MSNs) are monodisperse spherical-like particles with an average diameter of 195 ± 16 nm. The Brunauer-Emmett-Teller (BET) results showed that the TA-MSNs had a relatively high surface area (447 m(2)/g) and large pore volume (0.91 cm(3)/g), and the mean pore size was ca. 10.1 nm. Burkholderia cepacia lipase was immobilized on the TA-MSNs by physical adsorption for the first time, and the properties of immobilized lipase (BCL@TA-MSNs) were investigated. The BCL@TA-MSNs exhibited satisfactory thermal stability; strong tolerance to organic solvents such as methanol, ethanol, isooctane, n-hexane, and tetrahydrofuran; and high operational reusability when BCL@TA-MSNs were applied in esterification and transesterification reactions. After recycling 15 times in the transesterification reaction for biodiesel production, over 85 % of biodiesel yield can be maintained. With these desired characteristics, the TA-MSNs may provide excellent candidates for enzyme immobilization.

  7. Immobilization of Lipase on Silver Nanoparticles via Adhesive Polydopamine for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Kanchana Dumri

    2014-01-01

    Full Text Available Biodiesel production technology is competitive in terms of low cost and alternative source of energy which should be not only sustainable but also environmentally friendly. Designing of the lipase immobilization for biodiesel production has a remarkable impact and is still challenging. In this work, biodiesel production from soybean oil was enhanced and facilitated by using a novel biocatalyst consisting of commercial lipase (EC 3.1.1.3, silver nanoparticles, and polydopamine. Silver nanoparticles (AgNPs were synthesized with a size range of 10–20 nm. Polydopamine (PD was delivered by the self-polymerization of dopamine in 10 mM Tris-HCl pH 8.5 and simultaneously coated the AgNPs to form a PD/AgNPs complex. Lipase was immobilized on the PD/AgNPs complex surface via covalent bonds to form a tailor-made biocatalyst consisting of immobilized lipase/PD/AgNPs complex (LPA. The formation and morphology of each composition were characterized by UV-Vis spectroscopy and scanning electron microscope (SEM. Significantly, gas chromatography analysis showed a remarkable biodiesel production yield of 95% by using the LPA complex at 40°C for 6-hours reaction time, whereas the yield was 86% when using free lyophilized lipase. The LPA complex was apparently reusable after 7 batches and the latter conversion rate of soybean oil was decreased by only 27%.

  8. A new nanosensor composed of laminated samarium borate and immobilized laccase for phenol determination

    Science.gov (United States)

    Hu, Ping; Zhou, Xinlin; Wu, Qingsheng

    2014-02-01

    A new nanosensor composed of laminated samarium borate and immobilized laccase was developed for phenol determination. The laminated samarium borate was synthesized by a mild solid-state-hydrothermal (S-S-H) method without any surfactant or Template. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to characterize the samples. The morphology of the as-prepared materials was characterized by SEM, which shows that laminated samarium borate are uniform nanosheets with a layer-by-layer self-assembled single-crystal structure. These laminated samarium borate have typical diameters of 3 ~ 5 μm and the thickness of each layer is in the range of 10 ~ 80 nm. And then, these SmBO3 multilayers were used to immobilize the laccase. The proposed nanosensor composed of laminated samarium borate and immobilized laccase was successfully developed for phenol determination. Cyclic voltammetry were used to study the nanosensor. The proposed nanosensor displayed high sensitivity toward phenolic compounds. The linearity of the nanosensor for the detection of hydroquinone was obtained from 1 to 50 μM with a detection limit of 3 × 10-7 M (based on the S/N = 3).

  9. Universal biomimetic preparation and immobilization of layered double hydroxide films and adsorption behavior

    Science.gov (United States)

    Zhou, Wei; Zhang, Wenpeng; Chen, Zilin

    2017-01-01

    Preparation and immobilization of layered double hydroxides (LDHs) film onto multiple substrates is important and challenging in functional materials fields by date. In this work, a simple and universal polydopamine (PD)-based layer-by-layer assembly strategy was developed for the immobilization of LDHs film onto surfaces such as polypropylene chip, glass slides and metal coins. The surface of substrates was firstly modified by polydopamine functionalization, and then LDHs film was synthesized via urea method and directly immobilized on the PD layer by in situ growing strategy in one step. The PD layer as well as the final LDHs film was characterized by energy dispersive X-ray spectroscopy, scanning electron microscope, infrared spectroscopy, X-ray diffraction pattern and X-ray photoelectron spectra. It has been demonstrated the formation of the dense and homogeneous nanoscaled LDHs film with 400 nm thickness. Adsorption behavior of the fabricated NiAl-LDHs film toward anionic dyes and pharmaceuticals was further assessed. To demonstrate their extensive application, fast and high efficient adsorption of anionic dyes and pharmaceuticals was achieved by NiAl-LDHs-modified polypropylene centrifugal tube.

  10. Comparison of amino and epoxy functionalized SBA-15 used for carbonic anhydrase immobilization.

    Science.gov (United States)

    Fei, Xiaoyao; Chen, Shaoyun; Liu, Dai; Huang, Chunjie; Zhang, Yongchun

    2016-09-01

    Two functionalized SBA-15 [amine-functionalized SBA-15 (AFS) and epoxy-functionalized SBA-15 (GFS)] with different types of functional groups were synthesized by a hydrothermal process and post functionalized with 3-aminopropyltriethoxysilane (APTES) and 3-glycidyloxypropyltrimethoxysilane (GPTMS), respectively. They were used for the immobilization of carbonic anhydrase (CA). The physicochemical properties of the functionalized SBA-15 were characterized by X-ray powder diffraction (XRD), N2 adsorption-desorption, (13)C, (29)Si solid-state nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM). Before and after CA was immobilized on AFS and GFS, the effects of temperature and pH value on the enzyme activity, storage stability, and reusability were investigated using para-nitrophenyl acetate (p-NPA) assay. CA/GFS showed a better performance with respect to storage stability and reusability than CA/AFS. Moreover, the amount of CaCO3 precipitated over CA/AFS was less than that precipitated over CA/GFS, which was almost equal to that precipitated over the free CA. The results indicate that the epoxy group is a more suitable functional group for covalent bonding with CA than the amino group, and GFS is a promising support for CA immobilization.

  11. IMMOBILIZED CIBACRON BLUE F3G-A ON CROSSLINKED POLY (VINYL ALCOHOL) FOR AFFINITY CHROMATOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    YUAN Jing; YAN Husheng; CHENG Xiaohui; HE Binglin

    2001-01-01

    Immobilized triazine dye affinity chromatography has been widely used for protein purification. In this paper, cibacron Blue F3G-A was immobilized,through a spacer arm, onto a rigid hydrophilic porous polymer by reacting an epoxy-group-containing poly(vinyl alcohol) with 6-aminohexyl-N'-Cibacron Blue F3G-A,which was obtained by reacting Cibacron Blue F3G-A with excess of 1,6-diaminohexane, in a pH 8.6 buffer. The epoxy-group-containing poly(vinyl alcohol) was prepared by hydrolysis of macroporous crosslinded poly(vinyl acetate),which was synthesized by suspension copolymerization of vinyl acetate and triallyl isocyanurate in the presence of butyl acetate and n-heptane as diluents. The cibacron Blue F3G-A-immobilized poly(vinyl alcohol)was packed in a stainless steel column (250×5 mm I. D.) and the chromatographic behaviors of several proteins (cytochrome c, lysozyme, bovine serum albumin, insulin, and lactate dehydrogenase) were determined.

  12. Study on immobilization of yeast alcohol dehydrogenase on nanocrystalline Ni-Co ferrites as magnetic support.

    Science.gov (United States)

    Shakir, Mohammad; Nasir, Zeba; Khan, Mohd Shoeb; Lutfullah; Alam, Md Fazle; Younus, Hina; Al-Resayes, Saud Ibrahim

    2015-01-01

    The covalent binding of yeast alcohol dehydrogenase (YADH) enzyme complex in a series of magnetic crystalline Ni-Co nanoferrites, synthesized via sol-gel auto combustion technique was investigated. The structural analysis, morphology and magnetic properties of Ni-Co nanoferrites were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating-sample magnetometer (VSM), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The comparative analysis of the HRTEM micrographs of bare magnetic nanoferrite particles and particles immobilized with enzyme revealed an uniform distribution of the particles in both the cases without undergoing change in the size which was found to be in the range 20-30 nm. The binding of YADH to Ni-Co nanoferrites and the possible binding mechanism have been suggested by comparing the FTIR results. The binding properties of the immobilized YADH enzyme were also studied by kinetic parameters, optimum operational pH, temperature, thermal stability and reusability. The immobilized YADH exhibits enhanced thermal stability as compared to the free enzyme over a wide range of temperature and pH, and showed good durability after recovery by magnetic separation for repeated use.

  13. Solvent-Free Synthesis of Flavour Esters through Immobilized Lipase Mediated Transesterification.

    Science.gov (United States)

    Garlapati, Vijay Kumar; Banerjee, Rintu

    2013-01-01

    The synthesis of methyl butyrate and octyl acetate through immobilized Rhizopus oryzae NRRL 3562 lipase mediated transesterification was studied under solvent-free conditions. The effect of different transesterification variables, namely, molarity of alcohol, reaction time, temperature, agitation, addition of water, and enzyme amount on molar conversion (%) was investigated. A maximum molar conversion of 70.42% and 92.35% was obtained in a reaction time of 14 and 12 h with the transesterification variables of 0.6 M methanol in vinyl butyrate and 2 M octanol in vinyl acetate using 80 U and 60 U immobilized lipase with the agitation speed of 200 rpm and 0.2% water addition at 32°C and 36°C for methyl butyrate and octyl acetate, respectively. The immobilized enzyme has retained good relative activity (more than 95%) up to five and six recycles for methyl butyrate and octyl acetate, respectively. Hence, the present investigation makes a great impingement in natural flavour industry by introducing products synthesized under solvent-free conditions to the flavour market.

  14. Solvent-Free Synthesis of Flavour Esters through Immobilized Lipase Mediated Transesterification

    Directory of Open Access Journals (Sweden)

    Vijay Kumar Garlapati

    2013-01-01

    Full Text Available The synthesis of methyl butyrate and octyl acetate through immobilized Rhizopus oryzae NRRL 3562 lipase mediated transesterification was studied under solvent-free conditions. The effect of different transesterification variables, namely, molarity of alcohol, reaction time, temperature, agitation, addition of water, and enzyme amount on molar conversion (% was investigated. A maximum molar conversion of 70.42% and 92.35% was obtained in a reaction time of 14 and 12 h with the transesterification variables of 0.6 M methanol in vinyl butyrate and 2 M octanol in vinyl acetate using 80 U and 60 U immobilized lipase with the agitation speed of 200 rpm and 0.2% water addition at 32°C and 36°C for methyl butyrate and octyl acetate, respectively. The immobilized enzyme has retained good relative activity (more than 95% up to five and six recycles for methyl butyrate and octyl acetate, respectively. Hence, the present investigation makes a great impingement in natural flavour industry by introducing products synthesized under solvent-free conditions to the flavour market.

  15. Fabrication of Calix[4]arene Derivative Monolayers to Control Orientation of Antibody Immobilization

    Directory of Open Access Journals (Sweden)

    Hongxia Chen

    2014-03-01

    Full Text Available Three calix[4]arene (Cal-4 derivatives which separately contain ethylester (1, carboxylic acid (2, and crownether (3 at the lower rim with a common reactive thiol at the upper rim were synthesized and constructed to self-assembled monolayers (SAMs on Au films. After spectroscopic characterization of the monolayers, surface coverage and orientation of antibody immobilized on the Cal-4 derivative SAMs were studied by surface plasmon resonance (SPR technique. Experimental results revealed that the antibody could be immobilized on the Cal-4 derivatives spontaneously. The orientation of absorbed antibody on the Cal-4 derivative SAMs is related to the SAM’s dipole moment. The possible orientations of the antibody immobilized on the Cal-4 derivative 1 SAM are lying-on or side-on, while on the Cal-4 derivative 2 and Cal-4 derivative 3 head-on and end-on respectively. These experimental results demonstrate the surface dipole moment of Cal-4 derivative appears to be an important factor to antibody orientation. Cal-4 derivatives are useful in developing site direct protein chips.

  16. Use of cesium-137 methodology in the evaluation of superficial erosive processes

    Directory of Open Access Journals (Sweden)

    Avacir Casanova Andrello

    2003-06-01

    Full Text Available Superficial erosion is one of the main soil degradation agents and erosion rates estimations for different edaphicclimate conditions for the conventional models, as USLE and RUSLE, are expensive and time-consuming. The use of cesium-137 antrophogenic radionuclide is a new methodology that has been much studied and its application in the erosion soil evaluation has grown in countries as USA, UK, Australia and others. A brief narration of this methodology is being presented, as the development of the equations utilized for the erosion rates quantification through the cesium-137 measurements. Two watersheds studied in Brazil have shown that the cesium-137 methodology was practicable and coherent with the survey in field for applications in erosion studies.A erosão superficial é um dos principais agentes de degradação dos solos e estimativas das taxas de erosão para diferentes condições edafoclimáticas pelos modelos tradicionais como USLE, RUSLE, são onerosos e demorados. Uma metodologia que tem sido muito estudada e sua aplicação no estudo da erosão vem crescendo em países como EUA, Reino Unido, Austrália, e outros, é a do uso do radionuclídeo antropogênico césio-137. Um resumo da história desta metodologia é apresentado, assim como a evolução das equações utilizadas para quantificar as taxas de erosão através da medida do césio-137. Duas bacias estudadas no Brasil mostraram que a metodologia do césio-137 é viável e coerente com as observações em campo para aplicação no estudo da erosão.

  17. Al-free active region laser diodes at 894 nm for compact Cesium atomic clocks

    Science.gov (United States)

    Von Bandel, N.; Bébé Manga Lobé, J.; Garcia, M.; Larrue, A.; Robert, Y.; Vinet, E.; Lecomte, M.; Drisse, O.; Parillaud, O.; Krakowski, M.

    2015-03-01

    Time-frequency applications are in need of high accuracy and high stability clocks. Compact industrial Cesium atomic clocks optically pumped is a promising area that could satisfy these demands. However, the stability of these clocks relies, among others, on the performances of laser diodes that are used for atomic pumping. This issue has led the III-V Lab to commit to the European Euripides-LAMA project that aims to provide competitive compact optical Cesium clocks for earth applications. This work will provide key experience for further space technology qualification. We are in charge of the design, fabrication and reliability of Distributed-Feedback diodes (DFB) at 894nm (D1 line of Cesium) and 852nm (D2 line). The use of D1 line for pumping will provide simplified clock architecture compared to D2 line pumping thanks to simpler atomic transitions and larger spectral separation between lines in the 894nm case. Also, D1 line pumping overcomes the issue of unpumped "dark states" that occur with D2 line. The modules should provide narrow linewidth (<1MHz), very good reliability in time and, crucially, be insensitive to optical feedback. The development of the 894nm wavelength is grounded on our previous results for 852nm DFB. Thus, we show our first results from Al-free active region with InGaAsP quantum well broad-area lasers (100μm width, with lengths ranging from 2mm to 4mm), for further DFB operation at 894nm. We obtained low internal losses below 2cm-1, the external differential efficiency is 0.49W/A with uncoated facets and a low threshold current density of 190A/cm², for 2mm lasers at 20°C.

  18. Distribution of global fallouts cesium-137 in taiga and tundra catenae at the Ob River basin

    Science.gov (United States)

    Semenkov, I. N.; Usacheva, A. A.; Miroshnikov, A. Yu.

    2015-03-01

    The classification of soil catenae at the Ob River basin is developed and applied. This classification reflects the diverse geochemical conditions that led to the formation of certain soil bodies, their combinations and the migration fields of chemical elements. The soil and geochemical diversity of the Ob River basin catenae was analyzed. The vertical and lateral distribution of global fallouts cesium-137 was studied using the example of the four most common catenae types in Western Siberia tundra and taiga. In landscapes of dwarf birches and dark coniferous forests on gleysols, cryosols, podzols, and cryic-stagnosols, the highest 137Cs activity density and specific activity are characteristic of the upper soil layer of over 30% ash, while the moss-grass-shrub cover is characterized by low 137Cs activity density and specific activity. In landscapes of dwarf birches and pine woods on podzols, the maximum specific activity of cesium-137 is typical for moss-grass-shrub cover, while the maximum reserves are concentrated in the upper soil layer of over 30% ash. Bog landscapes and moss-grass-shrub cover are characterized by a minimum activity of 137Cs, and its reserves in soil generally decrease exponentially with depth. The cesium-137 penetration depth increases in oligotrophic histosols from northern to middle taiga landscapes from 10-15 to 40 cm. 137Cs is accumulated in oligotrophic histosols for increases in pH from 3.3 to 4.0 and in concretionary interlayers of pisoplinthic-cryic-histic-stagnosols. Cryogenic movement, on the one hand, leads to burying organic layers enriched in 137Cs and, on the other hand, to deducing specific activity when mixed with low-active material from lower soil layers.

  19. The chemical durability of glass and graphite-glass composite doped with cesium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hamodi, Nasir H., E-mail: nasirhamodi@yahoo.co.uk [School of Mechanical, Aerospace and Civil Engineering (MACE)/University of Manchester, Pariser Building, F-floor, Manchester M13 9PL (United Kingdom); Abram, Timothy J. [School of Mechanical, Aerospace and Civil Engineering (MACE)/University of Manchester, Pariser Building, F-floor, Manchester M13 9PL (United Kingdom); Lowe, Tristan; Cernik, Robert J. [Henry Mosley Imaging Facility, Material Science Centre, University of Manchester, Manchester M13 9PL (United Kingdom); Lopez-Honorato, Eddie [Centro de Investigacion y Estudios Avanzados del IPN (CINVESTAV), Unidad Saltillo. Carretera Saltillo-Monterrey km 13.5, 25900 Ramos Arizpe, Coahuila (Mexico)

    2013-01-15

    The role of temperature in determining the chemical stability of a waste form, as well as its leach rate, is very complex. This is because the dissolution kinetics is dependent both on temperature and possibility of different rate-controlling mechanisms that appear at different temperature regions. The chemical durability of Alumina-Borosilicate Glass (ABG) and Glass-Graphite Composite (GGC), bearing Tristructural Isotropic (TRISO) fuel particles impregnated with cesium oxide, were compared using a static leach test. The purpose of this study is to examine the chemical durability of glass-graphite composite to encapsulate coated fuel particles, and as a possible alternative for recycling of irradiated graphite. The test was based on the ASTM C1220-98 methodology, where the leaching condition was set at a temperature varying from 298 K to 363 K for 28 days. The release of cesium from ABG was in the permissible limit and followed the Arrhenius's law of a surface controlled reaction; its activation energy (E{sub a}) was 65.6 {+-} 0.5 kJ/mol. Similar values of Ea were obtained for Boron (64.3 {+-} 0.5) and Silicon (69.6 {+-} 0.5 kJ/mol) as the main glass network formers. In contrast, the dissolution mechanism of cesium from GGC was a rapid release, with increasing temperature, and the activation energy of Cs (91.0 {+-} 5 kJ/mol) did not follow any model related to carbon kinetic dissolution in water. Microstructure analysis confirmed the formation of Crystobalite SiO{sub 2} as a gel layer and Cs{sup +1} valence state on the ABG surface.

  20. Estimation of retention factor of cesium in sodium pool under fuel pin failure scenario in SFR

    Energy Technology Data Exchange (ETDEWEB)

    Pradeep, Arjun [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Rao, P. Mangarjuna, E-mail: pmr@igcar.gov.in [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Nashine, B.K.; Chellapandi, P. [Computational Simulation Section, Safety Engineering Division, Nuclear and Safety Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer We model retention factor of cesium in infinite dilute solution of sodium pool. Black-Right-Pointing-Pointer We study variation in retention factor with cover gas temperature gradient. Black-Right-Pointing-Pointer Increasing height and temperature difference decreases the retention factor. Black-Right-Pointing-Pointer In infinite dilution regime retention factor is independent of cesium inventory. Black-Right-Pointing-Pointer The retention factor is useful in estimating source term in cover gas region. - Abstract: Radioactive source term in argon (Ar) cover gas region of the primary vessel due to cesium (Cs) leaked from the failed fuel pins into the primary coolant of Sodium cooled Fast Reactor (SFR) depends on its thermodynamic and kinetic behavior with the coolant sodium. Evaluation of this source term requires detailed knowledge on the distribution of Cs between large volume of the liquid sodium, and the inert Ar cover gas. Solute-solvent combination like liquid Cs and sodium, with relative volatility greater than unity, is an important system to be analyzed in the context of SFR safety. Distribution of Cs between Ar cover gas and liquid sodium pool is complicated by the imposition of temperature difference across the cover gas region and its resultant enrichment of the more volatile solute. An analytical model has been developed to obtain the geometry dependent Retention Factor (RF) of Cs in the sodium pool as a function of the height of cover gas, initial mass inventory of Cs, the temperature difference across the cover gas region (between the sodium pool surface and top roof bottom plate) for an infinite dilute solution of Cs in the sodium pool. The model predicted results are validated with available experimental results in the literature and found that they are fairly in good agreement. In the infinite dilute solution (IDS) regime sodium pool is having the retention capacity to keep the Cs from being released into

  1. Research on the treatment of liquid waste containing cesium by an adsorption-microfiltration process with potassium zinc hexacyanoferrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Changping, E-mail: melindazhang@yahoo.com.cn [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China); Gu Ping, E-mail: guping@tju.edu.cn [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China); Zhao Jun; Zhang Dong; Deng Yue [Institute of Nuclear Physics and Chemistry, Chinese Academy of Engineering Physics, Mianyang 621900 (China)

    2009-08-15

    The removal of cesium from an aqueous solution by an adsorption-microfiltration (AMF) process was investigated in jar tests and lab-scale tests. The adsorbent was K{sub 2}Zn{sub 3}[Fe(CN){sub 6}]{sub 2}. The obtained cesium data in the jar test fit a Freundlich-type isotherm well. In the lab-scale test, the mean cesium concentration of the raw water and the effluent were 106.87 {mu}g/L and 0.59 {mu}g/L, respectively, the mean removal of cesium was 99.44%, and the mean decontamination factors (DF) and concentration factors (CF) were 208 and 539, respectively. The removal of cesium in the lab-scale test was better than that in the jar test because the old adsorbents remaining in the reactor still had adsorption capacity with the premise of no significant desorption being observed, and the continuous renewal of the adsorbent surface improved the adsorption capacity of the adsorbent. Some of the suspended solids were deposited on the bottom of the reactor, which would affect the mixing of adsorbents with the raw water and the renewing of the adsorbent surface. Membrane fouling was the main physical fouling mechanism, and the cake layer was the main filtration resistance. Specific flux (SF) decreased step by step during the whole period of operation due to membrane fouling and concentration polarization. The quality of the effluent was good and the turbidity remained lower than 0.1 NTU, and the toxic anion, CN{sup -}, could not be detected because of its low concentration, this indicated that the effluent was safe. The AMF process was feasible for practical application in the treatment of liquid waste containing cesium.

  2. Targeted Delivery of Hyaluronan-Immobilized Magnetic Ceramic Nanocrystals.

    Science.gov (United States)

    Wu, Hsi-Chin; Wang, Tzu-Wei; Hsieh, Shun-Yu; Sun, Jui-Sheng; Kang, Pei-Leun

    2016-01-01

    Effective cancer therapy relies on delivering the therapeutic agent precisely to the target site to improve the treatment outcome and to minimize side effects. Although surgery, chemotherapy, and radiotherapy are the standard methods commonly used in clinics, hyperthermia has been developed as a new and promising strategy for cancer therapy. In this study, magnetic bioceramic hydroxyapatite (mHAP) nanocrystals have been developed as heat mediator for intracellular hyperthermia. Hyaluronic acid (HA) modified mHAP nanocrystals are synthesized by a wet chemical precipitation process to achieve active targeting. The results demonstrate that the HA targeting moiety conjugated by a poly(ethylene glycol) (PEG) spacer arm is successfully immobilized on the surface of mHAP. The HA-modified mHAP possesses relatively good biocompatibility, an adequate biodegradation rate and superparamagnetic properties. The HA-modified mHAP could be localized and internalized into HA receptor-overexpressed malignant cells (e.g., MDA-MB-231 cell) and used as the heat generating agent for intracellular hyperthermia. The results from this study indicate that biocompatible HA-modified mHAP shows promise as a novel heat mediator and a specific targeting nanoagent for intracellular hyperthermia cancer therapy.

  3. Immobilization of amphiphilic polycations by catechol functionality for antimicrobial coatings.

    Science.gov (United States)

    Han, Hua; Wu, Jianfeng; Avery, Christopher W; Mizutani, Masato; Jiang, Xiaoming; Kamigaito, Masami; Chen, Zhan; Xi, Chuanwu; Kuroda, Kenichi

    2011-04-05

    A new strategy for preparing antimicrobial surfaces by a simple dip-coating procedure is reported. Amphiphilic polycations with different mole ratios of monomers containing dodecyl quaternary ammonium, methoxyethyl, and catechol groups were synthesized by free-radical polymerization. The polymer coatings were prepared by immersing glass slides into a polymer solution and subsequent drying and heating. The quaternary ammonium side chains endow the coatings with potent antibacterial activity, the methoxyethyl side chains enable tuning the hydrophobic/hydrophilic balance, and the catachol groups promote immobilization of the polymers into films. The polymer-coated surfaces displayed bactericidal activity against Escherichia coli and Staphylococcus aureus in a dynamic contact assay and prevented the accumulation of viable E. coli, S. aureus, and Acinetobacter baumannii for up to 96 h. Atomic force microscopy (AFM) images of coating surfaces indicated that the surfaces exhibit virtually the same smoothness for all polymers except the most hydrophobic. The hydrophobic polymer without methoxyethyl side chains showed clear structuring into polymer domains, causing high surface roughness. Sum-frequency generation (SFG) vibrational spectroscopy characterization of the surface structures demonstrated that the dodecyl chains are predominantly localized at the surface-air interface of the coatings. SFG also showed that the phenyl groups of the catechols are oriented on the substrate surface. These results support our hypothesis that the adhesive or cross-linking functionality of catechol groups discourages polymer leaching, allowing the tuning of the amphiphilic balance by incorporating hydrophilic components into the polymer chains to gain potent biocidal activity.

  4. Nanocrystals of Cesium Lead Halide Perovskites (CsPbX₃, X = Cl, Br, and I): Novel Optoelectronic Materials Showing Bright Emission with Wide Color Gamut.

    Science.gov (United States)

    Protesescu, Loredana; Yakunin, Sergii; Bodnarchuk, Maryna I; Krieg, Franziska; Caputo, Riccarda; Hendon, Christopher H; Yang, Ruo Xi; Walsh, Aron; Kovalenko, Maksym V

    2015-06-10

    Metal halides perovskites, such as hybrid organic-inorganic CH3NH3PbI3, are newcomer optoelectronic materials that have attracted enormous attention as solution-deposited absorbing layers in solar cells with power conversion efficiencies reaching 20%. Herein we demonstrate a new avenue for halide perovskites by designing highly luminescent perovskite-based colloidal quantum dot materials. We have synthesized monodisperse colloidal nanocubes (4-15 nm edge lengths) of fully inorganic cesium lead halide perovskites (CsPbX3, X = Cl, Br, and I or mixed halide systems Cl/Br and Br/I) using inexpensive commercial precursors. Through compositional modulations and quantum size-effects, the bandgap energies and emission spectra are readily tunable over the entire visible spectral region of 410-700 nm. The photoluminescence of CsPbX3 nanocrystals is characterized by narrow emission line-widths of 12-42 nm, wide color gamut covering up to 140% of the NTSC color standard, high quantum yields of up to 90%, and radiative lifetimes in the range of 1-29 ns. The compelling combination of enhanced optical properties and chemical robustness makes CsPbX3 nanocrystals appealing for optoelectronic applications, particularly for blue and green spectral regions (410-530 nm), where typical metal chalcogenide-based quantum dots suffer from photodegradation.

  5. Glucose oxidase immobilization onto carbon nanotube networking

    CERN Document Server

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  6. Enzyme-immobilized microfluidic process reactors.

    Science.gov (United States)

    Asanomi, Yuya; Yamaguchi, Hiroshi; Miyazaki, Masaya; Maeda, Hideaki

    2011-07-19

    Microreaction technology, which is an interdisciplinary science and engineering area, has been the focus of different fields of research in the past few years. Several microreactors have been developed. Enzymes are a type of catalyst, which are useful in the production of substance in an environmentally friendly way, and they also have high potential for analytical applications. However, not many enzymatic processes have been commercialized, because of problems in stability of the enzymes, cost, and efficiency of the reactions. Thus, there have been demands for innovation in process engineering, particularly for enzymatic reactions, and microreaction devices represent important tools for the development of enzyme processes. In this review, we summarize the recent advances of microchannel reaction technologies especially for enzyme immobilized microreactors. We discuss the manufacturing process of microreaction devices and the advantages of microreactors compared to conventional reaction devices. Fundamental techniques for enzyme immobilized microreactors and important applications of this multidisciplinary technology are also included in our topics.

  7. Enzyme-Immobilized Microfluidic Process Reactors

    Directory of Open Access Journals (Sweden)

    Hideaki Maeda

    2011-07-01

    Full Text Available Microreaction technology, which is an interdisciplinary science and engineering area, has been the focus of different fields of research in the past few years. Several microreactors have been developed. Enzymes are a type of catalyst, which are useful in the production of substance in an environmentally friendly way, and they also have high potential for analytical applications. However, not many enzymatic processes have been commercialized, because of problems in stability of the enzymes, cost, and efficiency of the reactions. Thus, there have been demands for innovation in process engineering, particularly for enzymatic reactions, and microreaction devices represent important tools for the development of enzyme processes. In this review, we summarize the recent advances of microchannel reaction technologies especially for enzyme immobilized microreactors. We discuss the manufacturing process of microreaction devices and the advantages of microreactors compared to conventional reaction devices. Fundamental techniques for enzyme immobilized microreactors and important applications of this multidisciplinary technology are also included in our topics.

  8. Design of a Carousel Process for Removing Cesium from SRS Waste Using Crystalline Silicotitanate Ion Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    1999-01-15

    Designs of a three-column carousel process based on crystalline silicotitanate (CST) ion exchanger have been developed for removing radioactive 137Cs+ from Savannah River Site's (SRS) nuclear wastes. A multicomponent ion exchange equilibrium model (Zheng et al., 1997) from Texas A&M University, which is based on batch data obtained from CST powder, is used to generate cesium loading data at different cesium concentrations for various types of SRS wastes. These loading data are fit to the Langmuir equation to obtain effective single-component cesium isotherm parameters. The predictions are in reasonable agreement with batch test data obtained from CST powder, an early CST pellet batch (38B), and a later batch (IE911) using two SRS waste simulants. The ratios between experimental cesium distribution coefficients and predicted values are between 0.56 and 1.0. The variation appears to be due to inadequate equilibration time in some of the batches. Mass transfer parameters are estimated by analyzing column data of a simulated SRS waste and Melton Valley Storage Tank W29 (MVST-W29) waste. The intraparticle diffusivity estimated for the two wastes can be well correlated by means of the Stokes-Einstein equation.Simulations are performed to determine the length of the mass transfer zone for given feed compositions, Cs+ concentrations, and linear velocities. In order to ensure high column utilization during both the transient and cyclic steady state periods, the length of a single segment in the carousel process is chosen to be the mass transfer zone length after the concentration wave achieves a constant pattern. Analysis of the dimensionless groups in the differential mass balance equations reveals that the normalized mass transfer zone length is linearly proportional to the particle Peclet number. The proportionality constant is a function of the waste composition and the Cs+ concentration in the waste. The higher the effective Cs+ capacity and the higher the Cs

  9. Optical and evaporative cooling of cesium atoms in the gravito-optical surface trap

    CERN Document Server

    Hammes, M; Druzhinina, V; Moslener, U; Manek-Hönninger, I; Grimm, R

    2000-01-01

    We report on cooling of an atomic cesium gas closely above an evanescent-wave atom mirror. At high densitities, optical cooling based on inelastic reflections is found to be limited by a density-dependent excess temperature and trap loss due to ultracold collisions involving repulsive molecular states. Nevertheless, very good starting conditions for subsequent evaporative cooling are obtained. Our first evaporation experiments show a temperature reduction from 10muK down to 300nK along with a gain in phase-space density of almost two orders of magnitude.

  10. Enhanced four-wave mixing via crossover resonance in cesium vapor

    CERN Document Server

    de Silans, T Passerat; Felinto, D; Tabosa, J W R

    2011-01-01

    We report on the observation of enhanced four-wave mixing via crossover resonance in a Doppler broadened cesium vapor. Using a single laser frequency, a resonant parametric process in a double-$\\Lambda$ level configuration is directly excited for a specific velocity class. We investigate this process in different saturation regimes and demonstrate the possibility of generating intensity correlation and anti-correlation between the probe and conjugate beams. A simple theoretical model is developed that accounts qualitatively well to the observed results.

  11. Theoretical analysis of parity violation induced by neutral currents in atomic cesium

    Energy Technology Data Exchange (ETDEWEB)

    Bouchiat, C.; Piketty, C.A.; Pignon, D. (Ecole Normale Superieure, 75 - Paris (France). Lab. de Physique Theorique)

    1983-07-04

    In this paper we give a theoretical analysis of the parity violation phenomena in nS-n'S transitions in atomic cesium induced by the electron-nucleus neutral-current interaction. The actual observation of parity violation consists in the measurement of an interference between the p.v. electric dipole amplitude E/sub 1/sup(pv) with the electric amplitude induced by a static electric field. Our theoretical work must then include a calculation of the diagonal and non-diagonal polarizabilities of the states of atomic cesium. We have used a one-electron model proposed by Norcross which incorporates some many-body effects like the electric screening induced by the core polarization in a semi-empirical way. Our calculated values of the diagonal and non-diagonal polarizabilities of the nS states are in good agreement with the existing measurements; this confirms the already well-established success of the model in predicting the radiative transitions in cesium. We present theoretical arguments supported by detailed numerical computations showing that the one-particle matrix element of the parity-violating electron-nucleus interaction and the parity-violating electric dipole amplitude E/sub 1/sup(pv) itself weakly depend on the shape of the one-electron potential provided the binding energies of the valence states are reproduced accurately. Furthermore it turns out that because of a compensation mechanism, the parity-violating transition is induced by the radiation field outside the ion core region where the screening can be described simply in terms of the measurable cesium ion polarizability. Our results are then used to extract, from the Ecole Normale Superieure experiment, a value of the weak charge Qsub(w)= -57.1+-9.4 (r.m.s. statistical deviation) +-4.7 (systematic uncertainty). This number is to be compared with the prediction of the Weinberg-Salam model with electro-weak radiative corrections: Qsub(w)=-68.6+-3.0.

  12. Parity violation in atomic cesium and alternatives to the standard model of electroweak interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bouchiat, C.; Piketty, C.A. (Ecole Normale Superieure, 75 - Paris (France). Lab. de Physique Theorique)

    1983-08-18

    We study the implications of the recent observation of a parity violation in atomic cesium. After a discussion of the uncertainties associated with the atomic physics calculations we derive conservative bounds for the weak charge Qsub(W). These bounds are used to put constraints on alternatives to the standard electroweak model, involving an 'extra U(1)' gauge group. We analyze the possibility that the extra gauge boson might be very light and give, as a by-product, the typical range of momentum transfer explored in atomic parity violation experiments.

  13. A theoretical analysis of parity violation induced by neutral currents in atomic cesium

    Science.gov (United States)

    Bouchiat, C.; Piketty, C. A.; Pignon, D.

    1983-07-01

    In this paper we give a theoretical analysis of the parity violation phenomena in nS - n'S transitions in atomic cesium induced by the electron-nucleus neutral-current interaction. The actual observation of parity violation consists in the measurement of an interference between the p.v. electric dipole amplitude Elpv with the electric amplitude induced by a static electric field. Our theoretical work must then include a calculation of the diagonal and non-diagonal polarizabilities of the states of atomic cesium. We have used a one-electron model proposed by Norcross which incorporates some many-body effects like the electric screening induced by the core polarization in a semi-empirical way. Our calculated values of the diagonal and non-diagonal polarizabilities of the nS states are in good agreement with the existing measurements; this confirms the already well-established success of the model in predicting the radiative transitions in cesium. We present theoretical arguments supported by detailed numerical computations showing that the one-particle matrix element of the parity-violating electron-nucleus interaction and the parity-violating electric dipole amplitude Elpv itself weakly depend on the shape of the one-electron potential provided the binding energies of the valence states are reproduced accurately. Furthermore it turns out that because of a compensation mechanism, the parity-violating transition is induced by the radiation field outside the ion core region where the screening can be described simply in terms of the measurable cesium ion polarizability. Our results are then used to extract, from the Ecole Normale Supérieure experiment, a value of the weak charge Qw = -57.1 ± 9.4 (r.m.s. statistical deviation) ± 4.7 (systematic uncertainty). This number is to be compared with the prediction of the Weinberg-Salam model with electro-weak radiative corrections: Qw = -68.6 ± 3.0. A general discussion of the uncertainties of the atomic physics

  14. Universality of the three-body parameter for Efimov states in ultracold cesium.

    Science.gov (United States)

    Berninger, M; Zenesini, A; Huang, B; Harm, W; Nägerl, H-C; Ferlaino, F; Grimm, R; Julienne, P S; Hutson, J M

    2011-09-16

    We report on the observation of triatomic Efimov resonances in an ultracold gas of cesium atoms. Exploiting the wide tunability of interactions resulting from three broad Feshbach resonances in the same spin channel, we measure magnetic-field dependent three-body recombination loss. The positions of the loss resonances yield corresponding values for the three-body parameter, which in universal few-body physics is required to describe three-body phenomena and, in particular, to fix the spectrum of Efimov states. Our observations show a robust universal behavior with a three-body parameter that stays essentially constant.

  15. Microcrystalline hexagonal tungsten bronze. 1. Basis of ion exchange selectivity for cesium and strontium.

    Science.gov (United States)

    Griffith, Christopher S; Luca, Vittorio; Hanna, John V; Pike, Kevin J; Smith, Mark E; Thorogood, Gordon S

    2009-07-06

    The structural basis of selectivity for cesium and strontium of microcrystalline hexagonal tungsten bronze (HTB) phase Na(x)WO(3+x/2).zH(2)O has been studied using X-ray and neutron diffraction techniques, 1D and 2D (23)Na magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and radiochemical ion exchange investigations. For the HTB system, this study has shown that scattering techniques alone provide an incomplete description of the disorder and rapid exchange of water (with tunnel cations) occurring in this system. However, 1D and 2D (23)Na MAS NMR has identified three sodium species within the HTB tunnels-species A, which is located at the center of the hexagonal window and is devoid of coordinated water, and species B and C, which are the di- and monohydrated variants, respectively, of species A. Although species B accords with the traditional crystallographic model of the HTB phase, this work is the first to propose and identify the anhydrous species A and monohydrate species C. The population (total) of species B and C decreases in comparison to that of species A with increasing exchange of either cesium or strontium; that is, species B and C appear more exchangeable than species A. Moreover, a significant proportion of tunnel water is redistributed by these cations. Multiple ion exchange investigations with radiotracers (137)Cs and (85)Sr have shown that for strontium there is a definite advantage in ensuring that any easily exchanged sodium is removed from the HTB tunnels prior to exchange. The decrease in selectivity (wrt cesium) is most probably due to the slightly smaller effective size of Sr(2+); namely, it is less of a good fit for the hexagonal window, ion exchange site. The selectivity of the HTB framework for cesium has been shown unequivocally to be defined by the structure of the hexagonal window, ion exchange site. Compromising the geometry of this window even in the slightest way by either (1) varying the cell volume through

  16. TMI-2 core debris-cesium release/settling test. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D W; Johnson, D A

    1984-12-01

    Cesium release, turbidity and airborne potential tests were conducted on 50 grams of TMI-2 core debris materials. The tests were performed on the debris in two conditions: on the as-received core debris specimen, and after crushing the debris to alter the particle size distribution. The crushing was intended to simulate the breakup of TMI-2 core material that may occur during reactor defueling. These tests are intended to assist GPU Nuclear in predicting the effect of defueling on the reactor environment.

  17. Accumulation of uranium, cesium, and radium by microbial cells: bench-scale studies

    Energy Technology Data Exchange (ETDEWEB)

    Strandberg, G.W.; Shumate, S.E. II

    1982-07-01

    This report describes bench-scale studies on the utilization of microbial cells for the concentration and removal of uranium, radium, and cesium from nuclear processing waste streams. Included are studies aimed at elucidating the basic mechanism of uranium uptake, process development efforts for the use of a combined denitrification-uranium removal process to treat a specific nuclear processing waste stream, and a preliminary investigation of the applicability of microorganisms for the removal of /sup 137/Cs and /sup 226/Ra from existing waste solutions.

  18. Sulfated fucan as support for antibiotic immobilization.

    Science.gov (United States)

    Araújo, P M; Oliveira, G B; Córdula, C R; Leite, E L; Carvalho Jr, L B; Silva, M P C

    2004-03-01

    Xylofucoglucuronan from Spatoglossum schröederi algae was tested as a support for antibiotic immobilization. The polysaccharide (20 mg in 6 ml) was first activated using carbodiimide, 1-ethyl-3-(3-dimethylamino-propyl)carbodiimide methiodide (20 mg in 2 ml), under stirring for 1 h at 25 masculine C and pH from 4.5 to 5.0. After adjusting the pH to 8.0, either gentamicin or amikacin (62.5 mg in 1.25 ml) was then immobilized on this chemically modified polysaccharide with shaking for 24 h in a cold room. Infrared spectra of the activated carbodiimide xylofucoglucuronan showed two bands to carbonyl (C=O at 1647.9 and 1700.7 cm(-1)) and to amide (C-NH2) groups (1662.8 and 1714.0 cm(-1)). Microbial characterization of the derivatives was carried out by the disk diffusion method using Staphylococcus aureus or Klebsiella pneumoniae incorporated in Müller Hinton medium. Inhibition halos of bacterial growth were observed for the antibiotics immobilized on this sulfated heteropolysaccharide before and after dialysis. However, the halos resulting from the samples after dialysis were much smaller, suggesting that dialysis removed either non-covalently bound antibiotic or other small molecules. In contrast, bacterial growth was not inhibited by either xylofucoglucuronan or its activated form or by gentamicin or amikacin after dialysis. An additional experiment was carried out which demonstrated that the sulfated heteropolysaccharide was hydrolyzed by the microorganism. Therefore, the antibiotic immobilized on xylofucoglucuronan can be proposed as a controlled drug delivery system. Furthermore, this sulfated heteropolysaccharide can be extracted easily from sea algae Spatoglossum schröederi.

  19. Combustion synthesis of radioactive waste immobilization

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ruizhu; GUO Zhimeng; LU Xin; JIA Chengchang; LIN Tao

    2005-01-01

    Using chromium oxide (CrO3) as an oxidant, the immobilization of simulating radioactive waste in perovskite (CaTiO3) structure by a combustion synthesis (CS) method was tested. The products were characterized by Archimedes liquid displacement technique, microhardness technique, X-ray diffraction, and scanning electron microscopy. The leaching rate was measured by the method of MCC-1 or MCC-2.The primary results show that the CS method can be used to solidify the immobilizate waste effectively.

  20. Sulfated fucan as support for antibiotic immobilization

    Directory of Open Access Journals (Sweden)

    Araújo P.M.

    2004-01-01

    Full Text Available Xylofucoglucuronan from Spatoglossum schröederi algae was tested as a support for antibiotic immobilization. The polysaccharide (20 mg in 6 ml was first activated using carbodiimide, 1-ethyl-3-(3-dimethylamino-propylcarbodiimide methiodide (20 mg in 2 ml, under stirring for 1 h at 25ºC and pH from 4.5 to 5.0. After adjusting the pH to 8.0, either gentamicin or amikacin (62.5 mg in 1.25 ml was then immobilized on this chemically modified polysaccharide with shaking for 24 h in a cold room. Infrared spectra of the activated carbodiimide xylofucoglucuronan showed two bands to carbonyl (C = O at 1647.9 and 1700.7 cm-1 and to amide (CÝ-NH2 groups (1662.8 and 1714.0 cm-1. Microbial characterization of the derivatives was carried out by the disk diffusion method using Staphylococcus aureus or Klebsiella pneumoniae incorporated in Müller Hinton medium. Inhibition halos of bacterial growth were observed for the antibiotics immobilized on this sulfated heteropolysaccharide before and after dialysis. However, the halos resulting from the samples after dialysis were much smaller, suggesting that dialysis removed either non-covalently bound antibiotic or other small molecules. In contrast, bacterial growth was not inhibited by either xylofucoglucuronan or its activated form or by gentamicin or amikacin after dialysis. An additional experiment was carried out which demonstrated that the sulfated heteropolysaccharide was hydrolyzed by the microorganism. Therefore, the antibiotic immobilized on xylofucoglucuronan can be proposed as a controlled drug delivery system. Furthermore, this sulfated heteropolysaccharide can be extracted easily from sea algae Spatoglossum schröederi.

  1. The Effect of Carbonate, Oxalate and Peroxide on the Cesium Loading of Ionsiv IE-910 and IE-911

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.F.

    2000-12-19

    The Savannah River Site (SRS) continues to examine three processes for the removal of radiocesium from high-level waste. One option involves the use of crystalline silicotitanate (CST) as a non-elutable ion exchange medium. The process uses CST in its engineered form - IONSIV IE-911 made by UOP, LLC. - in a column to contact the liquid waste. Cesium exchanges with sodium ions residing inside the CST particles. The design disposes of the cesium-loaded CST by vitrification within the Defense Waste Processing Facility.

  2. Graft linker immobilization for spatial control of protein immobilization inside fused microchips.

    Science.gov (United States)

    Shirai, Kentaro; Renberg, Björn; Sato, Kae; Mawatari, Kazuma; Konno, Tomohiro; Ishihara, Kazuhiko; Kitamori, Takehiko

    2009-12-01

    Fused silica glass microchips have several attractive features for lab-on-a-chip applications; they can be machined with excellent precision down to nanospace; are stable; transparent and can be modified with a range of silanization agents to change channel surface properties. For immobilization, however, ligands must be added after bonding, since the harsh bonding conditions using heat or hydrofluoric acid would remove all prior immobilized ligands. For spatial control over immobilization, UV-mediated immobilization offers several advantages; spots can be created in parallel, the feature size can be made small, and spatial control over patterns and positions is excellent. However, UV sensitive groups are often based on hydrophobic chemical moieties, which unfortunately result in greater non-specific binding of biomolecules, especially proteins. Here, we present techniques in which any -CH(x) (x=1,2,3) containing surface coating can be used as foundation for grafting a hydrophilic linker with a chemical anchor, a carboxyl group, to which proteins and amine containing molecules can be covalently coupled. Hence, the attractive features of many well-known protein and biomolecule repelling polymer coatings can be utilized while achieving site-specific immobilization only to pre-determined areas within the bonded microchips.

  3. Sufentanil citrate immobilization of Alaskan moose calves.

    Science.gov (United States)

    Kreeger, Terry J; Kellie, Kalin A

    2012-10-01

    Free-ranging Alaskan moose calves (Alces alces gigas) were immobilized with 0.12 mg/kg sufentanil (S; n=16), 0.12 mg/kg sufentanil plus 0.27 mg/kg xylazine (SX; n=11), or 0.007 mg/kg carfentanil plus 0.36 mg/kg xylazine (CX; n=13). Immobilants were antagonized with 1.2 mg/kg naltrexone (S) or 1.2 mg/kg naltrexone plus 2.4 mg/kg tolazoline (SX, CX). There were no differences in induction (P ≥ 0.29) or processing (P ≥ 0.44) times between groups. Moose given either S or SX had significantly shorter recovery times than moose given CX (P=0.001) and recovery times from S were shorter than from SX (P=0.02). Oxygen saturation values for all groups averaged 85 ± 8%, but were significantly higher (P=0.048) for CX (89 ± 7%) than for S (82 ± 8%). Based on these data, sufentanil at 0.1 mg/kg or sufentanil at 0.1 mg/kg plus xylazine at 0.25 mg/kg could provide effective remote immobilization for Alaskan moose calves and could be substituted for carfentanil or thiafentanil should the need arise.

  4. IMMOBILIZATION OF LYSOZYME IN POLYVINYL ALCOHOL CRYOGEL

    Directory of Open Access Journals (Sweden)

    S. S. Dekina

    2014-06-01

    Full Text Available The lysozyme immobilization in cryogel of polyvinyl alcohol and physico-chemical properties of obtained preparation was investigated. Hydrolytic activity of lysozyme was determined by bacteriolytic method, using Micrococcus lysodeikticus cells acetone powder as substrate. Protein content was determined by the Lowry–Hartree method. Immobilization of lysozyme was conducted by entrapment in polyvinyl alcohol gel with subsequent cycles of freezing-thawing. Antimicrobial activity was studied by standard disk-diffusional method. The hydrogel filmic coatings with antimicrobial action, insoluble at physiological conditions, with quantitative retaining of protein and hydrolytic activity of lysozyme were obtained. The product is characterized by the widened pH-profile of activity at acidic pH values, stability in acidic medium (pH 5.5 and at storage. Its antimicrobial action against Staphylococcus aureus ATCC 25923 F-49, Pseudomonas aeruginosa 415, Escherichia coli 055 K 59912/4 and Candida albicans ATCC 885-653 was noted. The proposed method of lysozyme immobilization allows to obtain stable, highly effective product with antimicrobial activity, prospective for usage in biomedical investigations.

  5. Production of ribitol by alginate-immobilized

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, E.C.; Molina, M.C.; Pedrosa, M.M.; Solas, M.T.; vicente, C.; Legaz, M.E. [Laboratorio de Fisiologia, Facultad de Biologia, Madrid (Spain)

    1995-12-01

    Cells of the lichen Cladonia verticillatis have been immobilized in calcium alginate and incubated for 15 days in light on different con centrations of sodium bicarbonate in order to produce lichen polyols. Sugars and polyols secreted to the medium were extracted and analyzed by HPLC. Production and secretion of both ribitol and glucose were very high by entrapped cells incubated on 10 mM sodium bicarbonate but the replacement of calcium by sodium in the alginate matrix produced the disorganization of the immobilized system in a period no longer tan 5 days. however, incubation of the entrapped cells on 1 mM sodium bicarbonate preserved the structure of the innert matrix although only ribitol was produced and secreted to the medium. Entrapment in sodium alginate maintained cell vitality although chloroplast disorganization of the phycobiont became evident. Moreover, contact between myco- and phycobiont has also been altered during immobilization since algal ribitol was not converted into mannitol by the fungal partner. 19 refs.

  6. Hydrophilic porous magnetic poly(GMA-MBAA-NVP) composite microspheres containing oxirane groups: An efficient carrier for immobilizing penicillin G acylase

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Ping; Su, Weiguang, E-mail: weiguangsu@nxu.edu.cn; Gu, Yaohua; Liu, Haifeng; Wang, Julan

    2015-03-15

    Magnetic hydrophilic polymeric microspheres containing oxirane groups were prepared by inverse suspension polymerization of glycidyl methacrylate (GMA), N, N′-methylene bisacrylamide (MBAA) and N-vinyl pyrrolidone (NVP) in the existence of formamide, which were denoted as magnetic poly(GMA-MBAA-NVP) microspheres. The magnetic poly(GMA-MBAA-NVP) microspheres were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy, X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and so on. The results showed that poly(GMA-MBAA-NVP) microspheres possessed well spherical shape, narrow size distribution, abundant porous structure, reactive oxirane groups and superparamagnetic properties. Formamide used in the present work served as a modifier, a dispersant and a porogen to form final porous polymer microspheres. The penicillin G acylase (PGA) was covalently immobilized onto the magnetic microspheres through the reaction between the amino groups of enzyme and the oxirane groups on the microspheres for producing 6-aminopenicillanic acid (6-APA). The effects of GMA/NVP ratio and crosslink density on the activity of immobilized PGA were investigated. The highest apparent activity, enzyme loading and coupling yield of immobilized PGA were 821 IU/g, 65.3 mg/g and 42.3% respectively when the mass ratio of GMA/NVP was 1:1 and crosslink density was 60%. Compared with the free PGA, immobilized PGA showed a wider range of pH value and reaction temperature. The relative activity and reaction rate of immobilized PGA remained almost constant after 20 recycles. The magnetic poly(GMA-MBAA-NVP) microspheres would be very promising carriers for immobilizing enzymes in industrial application. - Highlights: • The magnetic poly(GMA-MBAA-NVP) microspheres were successfully synthesized. • Formamide served as a modifier, a dispersant and a porogen to form microspheres. • The magnetic microspheres were highly efficient carriers for immobilizing PGA. • Immobilized PGA

  7. Immobilization of Magnetic Nanoparticles onto Amine-Modified Nano-Silica Gel for Copper Ions Remediation

    Directory of Open Access Journals (Sweden)

    Marwa Elkady

    2016-06-01

    Full Text Available A novel nano-hybrid was synthesized through immobilization of amine-functionalized silica gel nanoparticles with nanomagnetite via a co-precipitation technique. The parameters, such as reagent concentrations, reaction temperature and time, were optimized to accomplish the nano-silica gel chelating matrix. The most proper amine-modified silica gel nanoparticles were immobilized with magnetic nanoparticles. The synthesized magnetic amine nano-silica gel (MANSG was established and characterized using X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, Fourier transform infrared (FTIR, thermal gravimetric analysis (TGA, differential scanning calorimetry (DSC and vibrating sample magnetometry (VSM. The feasibility of MANSG for copper ions’ remediation from wastewater was examined. MANSG achieves a 98% copper decontamination from polluted water within 90 min. Equilibrium sorption of copper ions onto MANSG nanoparticles obeyed the Langmuir equation compared to the Freundlich, Temkin, Elovich and Dubinin-Radushkevich (D-R equilibrium isotherm models. The pseudo-second-order rate kinetics is appropriate to describe the copper sorption process onto the fabricated MANSG.

  8. Separation, Concentration, and Immobilization of Technetium and Iodine from Alkaline Supernate Waste

    Energy Technology Data Exchange (ETDEWEB)

    James Harvey; Michael Gula

    1998-12-07

    Development of remediation technologies for the characterization, retrieval, treatment, concentration, and final disposal of radioactive and chemical tank waste stored within the Department of Energy (DOE) complex represents an enormous scientific and technological challenge. A combined total of over 90 million gallons of high-level waste (HLW) and low-level waste (LLW) are stored in 335 underground storage tanks at four different DOE sites. Roughly 98% of this waste is highly alkaline in nature and contains high concentrations of nitrate and nitrite salts along with lesser concentrations of other salts. The primary waste forms are sludge, saltcake, and liquid supernatant with the bulk of the radioactivity contained in the sludge, making it the largest source of HLW. The saltcake (liquid waste with most of the water removed) and liquid supernatant consist mainly of sodium nitrate and sodium hydroxide salts. The main radioactive constituent in the alkaline supernatant is cesium-137, but strontium-90, technetium-99, and transuranic nuclides are also present in varying concentrations. Reduction of the radioactivity below Nuclear Regulatory Commission (NRC) limits would allow the bulk of the waste to be disposed of as LLW. Because of the long half-life of technetium-99 (2.1 x 10 5 y) and the mobility of the pertechnetate ion (TcO 4 - ) in the environment, it is expected that technetium will have to be removed from the Hanford wastes prior to disposal as LLW. Also, for some of the wastes, some level of technetium removal will be required to meet LLW criteria for radioactive content. Therefore, DOE has identified a need to develop technologies for the separation and concentration of technetium-99 from LLW streams. Eichrom has responded to this DOE-identified need by demonstrating a complete flowsheet for the separation, concentration, and immobilization of technetium (and iodine) from alkaline supernatant waste.

  9. Nanophotonic hybridization of narrow atomic cesium resonances and photonic stop gaps of opaline nanostructures

    CERN Document Server

    Harding, Philip J; Mosk, Allard P; Vos, Willem L

    2014-01-01

    We study a hybrid system consisting of a narrowband atomic optical resonance and the long-range periodic order of an opaline photonic nanostructure. To this end, we have infiltrated atomic cesium vapor in a thin silica opal photonic crystal. With increasing temperature, the frequencies of the opal's reflectivity peaks shift down by >20% due to chemical reduction of the silica. Simultaneously, the photonic bands and gaps shift relative to the fixed near-infrared cesium D1 transitions. As a result the narrow atomic resonances with high finesse (f/df=8E5) dramatically change shape from a usual dispersive shape at the blue edge of a stop gap, to an inverted dispersion lineshape at the red edge of a stop gap. The lineshape, amplitude, and off-resonance reflectivity are well modeled with a transfer-matrix model that includes the dispersion and absorption of Cs hyperfine transitions and the chemically-reduced opal. An ensemble of atoms in a photonic crystal is an intriguing hybrid system that features narrow defect-...

  10. Research on ultracold cesium molecule long-range states by high-resolution photoassociative spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WANG LiRong; MA Jie; JI WeiBang; WANG GuiPing; XIAO LianTuan; JIA SuoTang

    2008-01-01

    In this paper, an ultra-high resolution photoassociation spectroscopy study on photoassociation of cesium atoms is reported. The cold cesium gas in the mag-neto-optical trap is illuminated by a photoassociation laser with red-tuning as large as 40 cm-1 below the 6S1/2 + 6P3/2 dissociation limit, and the photoassoclation to the excited state ultracold molecule is detected. High signal-to-noise ratio is obtained by using the lock-in detection of the fluorescence from the modulated cold Cs at-oms. The O-g, and O+u, long-range states which correspond to 6S1/2 + 6P3/2 diSsocia-tion limit are present in the photoassociation spectrum. The effective coefficients of leading long-range interactions and the corresponding vibrational quantum num-ber are obtained using LeRoy-Bernstein Law. It is found that photoassociation process creates rotating molecules and the high J value is a hint that higher partial waves participate in the PA process in the presence of trapping laser.

  11. Effect of electrode materials on a negative ion production in a cesium seeded negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Takashi; Morishita, Takutoshi; Kashiwagi, Mieko; Hanada, Masaya; Iga, Takashi; Inoue, Takashi; Watanabe, Kazuhiro; Imai, Tsuyoshi [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Wada, Motoi [Doshisha Univ., Kyoto (Japan)

    2003-03-01

    Effects of plasma grid materials on the negative ion production efficiency in a cesium seeded ion source have been experimentally studied. Grid materials of Au, Ag, Cu, Ni, and Mo were examined. A 2.45 GHz microwave ion source was utilized in the experiment to avoid contamination of tungsten from filament cathode. Relations between the negative ion currents and work functions of the grid were measured for these materials. Influence of the contamination by tungsten on the grid was also investigated. If was clarified that the negative ion production efficiency was determined only by the work function of the grid. The efficiency did not depend on the material itself. The lowest work function of 1.42 eV was obtained for Au grid with Cs, and a high H{sup -} production efficiency of 20.7 mA/kW was measured. This efficiency is about 1.3 times larger than that of Cs/Mo and Cs/Cu. Further improvement of the production efficiency was observed by covering the plasma grid with tungsten and cesium simultaneously. Such co-deposition of W and Cs on the plasma grid produced the negative ion production efficiency of 1.7 times higher than that from the tungsten grid simply covered with Cs. (author)

  12. Experimental approaches to assessing the impact of a cesium chloride radiological dispersal device

    Science.gov (United States)

    Lee, S.; Gibb, Snyder E.; Barzyk, J.; McGee, J.; Koenig, A.

    2008-01-01

    The US EPA, as a part of the Chemical, Biological, Radiological-Nuclear, and Explosives (CBRNE) Research and Technology Initiative (CRTI) project team, is currently working to assess the impacts of an urban radiological dispersion device (RDD) and to develop containment and decontamination strategies. Three efforts in this area are currently underway: development of a laboratory-scale cesium chloride deposition method to mimic a RDD; assessment of cesium (Cs) penetration depth and pathways in urban materials using two dimensional (2-D) mapping laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS); and experimental determination of distribution coefficients (kd) for Cs in water-building material systems. It is critical that, when performing laboratory-scale experiments to assess the fate of Cs from an RDD, the Cs particle deposition method mimics the RDD deposition. Once Cs particles are deposited onto urban surfaces, 2-D mapping of Cs concentrations using LA-ICP-MS is a critical tool for determining Cs transport pathways through these materials. Lastly, distribution coefficients are critical for understanding the transport of Cs in urban settings when direct measurements of its penetration depth are unavailable. An assessment of the newly developed deposition method along with preliminary results from the penetration experiments are presented in this paper.

  13. Phase noise analysis of voltage controlled oscillator used in cesium atomic clock

    Science.gov (United States)

    Zhi, Menghui; Tang, Liang; Qiao, Donghai

    2017-03-01

    Coherent population trapping (CPT) cesium frequency standard plays a significant role in precision guidance of missile and global positioning system (GPS). Low noise 4.596 GHz voltage controlled oscillator (VCO) is an indispensable part of microwave signal source in cesium frequency standard. Low-phase noise is also the most important and difficult performance indicator of VCO. Starting from phase noise analysis method proposed by Leeson, the formulas about the relationship between phase noise of output signal of oscillator feedback model and phase fluctuation spectrum of amplifier, phase noise of oscillator are derived in this paper. Finally, the asymptote model of microwave oscillator is proposed based on the formula derivation. The experiment shows that when the reverse bias voltage of variode is 1.8 V, the designed oscillation frequency of VCO is 4.596 GHz, the power is ‑1 dBm and the DC power consumption is 19.6 mW. The tendency of phase noise simulation curve and actual test curve conform to asymptote model. The phase noise in 1 and 10 kHz is, respectively, ‑60.86 and ‑86.58 dBc/Hz. The significance of the paper lies in determining the main factors influencing oscillator phase noise and providing guiding direction for the design of low-phase noise VCO.

  14. Invertase immobilization onto radiation-induced graft copolymerized polyethylene pellets

    Science.gov (United States)

    de Queiroz, Alvaro Antonio Alencar; Vitolo, Michele; de Oliveira, Rômulo Cesar; Higa, Olga Zazuco

    1996-06-01

    The graft copolymer poly(ethylene-g-acrylic acid) (LDPE-g-AA) was prepared by radiation-induced graft copolymerization of acrylic acid onto low density polyethylene (LDPE) pellets, and characterized by infrared photoacoustic spectroscopy and scanning electron microscopy (SEM). The presence of the grafted poly(acrylic acid) (PAA) was established. Invertase was immobilized onto the graft polymer and the thermodynamic parameters of the soluble and immobilized enzyme were determined. The Michaelis constant, Km, and the maximum reaction velocity, Vmax, were determined for the free and the immobilized invertase. The Michaelis constant, Km was larger for the immobilized invertase than for the free enzyme, whereas Vmax was smaller for the immobilized invertase. The thermal stability of the immobilized invertase was higher than that of the free enzyme.

  15. The immobilization of lipase on PVDF-co-HFP membrane

    Science.gov (United States)

    Kayhan, Naciye; Eyüpoǧlu, Volkan; Adem, Şevki

    2016-04-01

    Lipase is an enzyme having a lot of different industrial applications such as biodiesel production, biopolymer synthesis, enantiopure pharmaceutical productions, agrochemicals, etc. Its immobilized form on different substances is more conventional and useful than its free form. Supporting material was prepared using PVDF-co-HFP in laboratory conditions and attached 1,4-diaminobutane (DA) and epichlorohydrin (EPI) ligands to the membrane to immobilize lipase enzyme. The immobilization conditions such as enzyme amount, pH, the concentration of salt, thermal stability and activity were stabilized for our experimental setup. Then, biochemical characterizations were performed on immobilized lipase PVDF-co-HFP regarding optimal pH activity, temperature and thermal stability. Also, the desorption ratios of immobilized enzyme in two different pathway were investigated to confirm immobilization stability for 24 hours.

  16. Byssus thread: a novel support material for urease immobilization.

    Science.gov (United States)

    Mishra, Neelam; Pithawala, Kespi; Bahadur, Anita

    2011-12-01

    Byssus threads are tough biopolymer produced by mussels (Mytilus viridis) to attach themselves to rocks. These were collected from mussels in their natural habitat (N) and from animals maintained in laboratory condition (L) as a novel support. Byssus thread surfaces were characterized by SEM analysis, chemically modified and used for adsorption of urease. The efficiency of the immobilization was calculated by examining the relative enzyme activity of free and the immobilized urease. The pH stabilities of immobilized urease were higher (0.5 unit) than free enzyme. Immobilized enzymes on byssus (both N and L) when stored at 6 °C retained 50% of its activity after 30 days, but they were more stable in dry condition. The optimum temperature of immobilized enzymes was found to increase (25 °C). A Michaelis-Menten constant (K (m)) value for immobilized urease was also elevated (2.08 mol).

  17. Covalent immobilization of Pseudomonas cepacia lipase on semiconducting materials

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Renny Edwin [Microelectronics and MEMS Laboratory, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai (India)], E-mail: rennyedwin@gmail.com; Bhattacharya, Enakshi [Microelectronics and MEMS Laboratory, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai (India)], E-mail: enakshi@ee.iitm.ac.in; Chadha, Anju [Department of Biotechnology, National Centre for Catalysis Research, Indian Institute of Technology Madras, Chennai (India)], E-mail: anjuc@iitm.ac.in

    2008-05-30

    Lipase from Pseudomonas cepacia was covalently immobilized on crystalline silicon, porous silicon and silicon nitride surfaces. The various stages of immobilization were characterized using FTIR (Fourier transform infrared) spectroscopy. The surface topography of the enzyme immobilized surfaces was investigated using scanning electron microscopy (SEM). The quantity of the immobilized active enzyme was estimated by the para-nitrophenyl palmitate (pNPP) assay. The immobilized lipase was used for triglyceride hydrolysis and the acid produced was detected by a pH sensitive silicon nitride surface as a shift in the C-V (capacitance-voltage) characteristics of an electrolyte-insulator-semiconductor capacitor (EISCAP) thus validating the immobilization method for use as a biosensor.

  18. Aroma formation by immobilized yeast cells in fermentation processes.

    Science.gov (United States)

    Nedović, V; Gibson, B; Mantzouridou, T F; Bugarski, B; Djordjević, V; Kalušević, A; Paraskevopoulou, A; Sandell, M; Šmogrovičová, D; Yilmaztekin, M

    2015-01-01

    Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale-up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes.

  19. Immobilization of activated sludge using improved polyvinyl alcohol (PVA) gel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microbial immobilization method using polyvinyl alcohol (PVA) gel as an immobilizing material was improved and used for entrapment of activated sludge. The OUR (oxygen uptake rate) was used to characterize the biological activity of immobilized activated sludge. Three kinds of PVA-immobilized particles of activated sludge, that is, PVA-boric acid beads, PVA-sodium nitrate beads and PVA-orthophosphate beads was prepared, and their biological activity was compared by measuring the OUR value. The bioactivity of both autotrophic and heterotrophic microorganisms of activated sludge was determined using different synthetic wastewater media (containing 250 mg/L COD and 25 mg/L NH4+-N). The experimental results showed that the bioactivity and stability of the three kinds of immobilized activated sludge was greatly improved after activation. With respect of the bioactivity and the mechanical stability, the PVA-orthophosphate method may be a promising and economical technique for microbial immobilization.

  20. Cystamine immobilization on TiO 2 film surfaces and the influence on inhibition of collagen-induced platelet activation

    Science.gov (United States)

    Zhou, Yujuan; Weng, Yajun; Zhang, Liping; Jing, Fengjuan; Huang, Nan; Chen, Junying

    2011-12-01

    Poor haemocompatibility is a main issue of artificial cardiovascular materials in clinical application. Nitric oxide (NO), produced by vascular endothelial cells, is a well known inhibitor of platelet adhesion and activation. Thus, NO-releasing biomaterials are beneficial for improving haemocompatibility of blood-contacting biomedical devices. In this paper, a novel method was developed for enhancement of haemocompatibility by exploiting endogenous NO donors. TiO 2 films were firstly synthesized on Si (1 0 0) wafers via unbalanced magnetron sputtering technology, and then polydopamine was grafted on TiO 2 films and used as a linker for further immobilization of cystamine. The obtained surfaces were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. NO generation is evaluated by saville-griess reagents, and it shows that cystamine immobilized samples are able to catalytically generate NO by decomposing endogenous S-nitrosothiols (RSNO). In vitro platelet adhesion results reveal that cystamine modified surfaces can inhibit collagen-induced platelet activation. ELISA analysis reveals that cGMP in platelets obviously increases on cystamine immobilized surface, which suggests the reducing of platelet activation is through NO/cGMP signal channel. It can be concluded that cystamine immobilized surface shows better blood compatibility by catalyzing NO release from the endogenous NO donor. It may be a promising method for improvement of haemocompatibility of blood-contacting implants.