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Sample records for metal-ion affinity chromatography

  1. Comparison of different transition metal ions for immobilized metal affinity chromatography of selenoprotein P from human plasma

    DEFF Research Database (Denmark)

    Sidenius, U; Farver, O; Jøns, O

    1999-01-01

    Cu2+, Ni2+, Zn2+, Co2+ and Cd2+ were evaluated in metal ion affinity chromatography for enrichment of selenoprotein P, and immobilized Co2+ affinity chromatography was found to be the most selective chromatographic method. The chromatography was performed by fast protein liquid chromatography...

  2. Adsorption of endotoxins on Ca2+ -iminodiacetic acid by metal ion affinity chromatography.

    Science.gov (United States)

    Lopes, André Moreni; Romeu, Jorge Sánchez; Meireles, Rolando Páez; Perera, Gabriel Marquez; Morales, Rolando Perdomo; Pessoa, Adalberto; Cárdenas, Lourdes Zumalacárregui

    2012-11-01

    Endotoxins (also known as lipopolysaccharides (LPS)) are undesirable by-products of recombinant proteins, purified from Escherichia coli. LPS can be considered stable under a wide range of temperature and pH, making their removal one of the most difficult tasks in downstream processes during protein purification. The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration. Immobilized metal affinity chromatography (IMAC) enables the affinity interactions between the metal ions (immobilized on the support through the chelating compound) and the target molecules, thus enabling high-efficiency separation of the target molecules from other components present in a mixture. Affinity chromatography is applied with Ca2+ -iminodiacetic acid (IDA) to remove most of the LPS contaminants from the end product (more than 90%). In this study, the adsorption of LPS on an IDA-Ca2+ was investigated. The adsorption Freundlich isotherm of LPS-IDA-Ca2+ provides a theoretical basis for LPS removal. It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ ligands on the beads. The factors such as pH (4.0 or 5.5) and ionic strength (1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin' concentration values less than 100 EU/mL and 100 000 EU/mL. This new protocol represents a substantial advantage in time, effort, and production costs.

  3. Immobilised metal-ion affinity chromatography purification of histidine-tagged recombinant proteins : a wash step with a low concentration of EDTA

    NARCIS (Netherlands)

    Westra, DF; Welling, GW; Koedijk, DGAM; Scheffer, AJ; The, TH; Welling-Wester, S

    2001-01-01

    Immobilised metal-ion affinity chromatography (IMAC) is widely used for the purification of recombinant proteins in which a poly-histidine tag is introduced. However, other proteins may also bind to IMAC columns. We describe the use of a washing buffer with a low concentration of EDTA (0.5 mM) for

  4. Two-step purification of His-tagged Nef protein in native condition using heparin and immobilized metal ion affinity chromatographies.

    Science.gov (United States)

    Finzi, Andrés; Cloutier, Jonathan; Cohen, Eric A

    2003-07-01

    The Nef protein encoded by human immunodeficiency virus type 1 (HIV-1) has been shown to be an important factor of progression of viral growth and pathogenesis in both in vitro and in vivo. The lack of a simple procedure to purify Nef in its native conformation has limited molecular studies on Nef function. A two-step procedure that includes heparin and immobilized metal ion affinity chromatographies (IMACs) was developed to purify His-tagged Nef (His(6)-Nef) expressed in bacteria in native condition. During the elaboration of this purification procedure, we identified two closely SDS-PAGE-migrating contaminating bacterial proteins, SlyD and GCHI, that co-eluted with His(6)-Nef in IMAC in denaturing condition and developed purification steps to eliminate these contaminants in native condition. Overall, this study describes a protocol that allows rapid purification of His(6)-Nef protein expressed in bacteria in native condition and that removes metal affinity resin-binding bacterial proteins that can contaminate recombinant His-tagged protein preparation.

  5. Large-scale analysis of in Vivo phosphorylated membrane proteins by immobilized metal ion affinity chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Nühse, Thomas S; Stensballe, Allan; Jensen, Ole N

    2003-01-01

    specificity. We investigated the potential of IMAC in combination with capillary liquid chromatography coupled to tandem mass spectrometry for the identification of plasma membrane phosphoproteins of Arabidopsis. Without chemical modification of peptides, over 75% pure phosphopeptides were isolated from...... plasma membrane digests and detected and sequenced by mass spectrometry. We present a scheme for two-dimensional peptide separation using strong anion exchange chromatography prior to IMAC that both decreases the complexity of IMAC-purified phosphopeptides and yields a far greater coverage...... of monophosphorylated peptides. Among the identified sequences, six originated from different isoforms of the plasma membrane H(+)-ATPase and defined two previously unknown phosphorylation sites at the regulatory C terminus. The potential for large-scale identification of phosphorylation sites on plasma membrane...

  6. Chromatography Of Metal Ions On Wood Cellulose Impregnated ...

    African Journals Online (AJOL)

    Adsorption chromatography of some heavy metal ions on wood cellulose of saw dust (wood waste dust) modified with hydrochloric acid, urea and thiourea was studied. Atomic absorption spectrophotometry (AAS) was used to determine the initial concentration of solutions of Zn2+, Cu2+, Ni2+, Pb2+, and Fe3+ metal ions.

  7. Report: Affinity Chromatography.

    Science.gov (United States)

    Walters, Rodney R.

    1985-01-01

    Supports, affinity ligands, immobilization, elution methods, and a number of applications are among the topics considered in this discussion of affinity chromatography. An outline of the basic principles of affinity chromatography is included. (JN)

  8. 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...... charged metal ions such as Fe3+, Ga3+, Al3+, Zr4+, and Ti4+ has made it possible to enrich phosphorylated peptides from peptide samples. However, the selectivity of most of the metal ions is limited, when working with highly complex samples, e.g., whole-cell extracts, resulting in contamination from...

  9. The connection between metal ion affinity and ligand affinity in integrin I domains

    DEFF Research Database (Denmark)

    Vorup-Jensen, Thomas; Waldron, TT; Astrof, N

    2007-01-01

    Integrins are cell-surface heterodimeric proteins that mediate cell-cell, cell-matrix, and cell-pathogen interactions. Half of the known integrin alpha subunits contain inserted domains (I domains) that coordinate ligand through a metal ion. Although the importance of conformational changes withi...

  10. Chromatography of metal ions with a triazine chelating resin

    International Nuclear Information System (INIS)

    Wang, W.N.

    1979-05-01

    The synthesis, characterization, and some analytical applications of a new triazine resin are described. Separation of group IB, IIB, VIB, and VIIB metal ions from group VIII metal ions is achieved by this PDT-4 resin. Calcium(II) and magnesium(II) are taken up at pH = 6, 0.1 M acetate and are eluted at pH = 6, 0.1 M sodium nitrate. Copper(II) is retained at pH = 6, 0.1 M acetate and pH = 1 hydrochloric acid and is eluted subsequently by 5 M perchloric acid. Molybdenum(VI) is sorbed selectively from 0.1 N sulfuric acid or hydrochloric acid and is eluted in a tight band by 0.1 N sodium hydroxide. Numerous rapid column chromatographic separations are reported using this new resin, including analysis of NBS standard samples

  11. New polymer-supported ion-complexing agents: Design, preparation and metal ion affinities of immobilized ligands

    International Nuclear Information System (INIS)

    Alexandratos, Spiro D.

    2007-01-01

    Polymer-supported reagents are comprised of crosslinked polymer networks that have been modified with ligands capable of selective metal ion complexation. Applications of these polymers are in environmental remediation, ion chromatography, sensor technology, and hydrometallurgy. Bifunctional polymers with diphosphonate/sulfonate ligands have a high selectivity for actinide ions. The distribution coefficient for the uranyl ion from 1 M nitric acid is 70,000, compared to 900 for the monophosphonate/sulfonate polymer and 200 for the sulfonic acid ion-exchange resin. A bifunctional trihexyl/triethylammonium polymer has a high affinity and selectivity for pertechnetate and perchlorate anions from groundwater. In one example, its distribution coefficient for perchlorate ions in the presence of competing anions is 3,300,000, compared to 203,180 for a commercially available anion-exchange resin. Polystyrene modified with N-methyl-D-glucamine ligands is capable of selectively complexing arsenate from groundwater. It complexes 99% of the arsenate present in a solution of 100 mg/L arsenate with 560 mg/L sulfate ions. Its selectivity is retained even in the presence of 400 mg/L phosphate. There is no affinity for arsenate above pH 9, allowing for the polymer to be regenerated with moderate alkali solution. In studies aimed at developing a Hg(II)-selective resin, simple amine resins were found to have a high Hg(II) affinity and that affinity is dependent upon the solution pH and the counterion

  12. PHARMACEUTICAL AND BIOMEDICAL APPLICATIONS OF AFFINITY CHROMATOGRAPHY: RECENT TRENDS AND DEVELOPMENTS

    Science.gov (United States)

    Hage, David S.; Anguizola, Jeanethe A.; Bi, Cong; Li, Rong; Matsuda, Ryan; Papastavros, Efthimia; Pfaunmiller, Erika; Vargas, John; Zheng, Xiwei

    2012-01-01

    Affinity chromatography is a separation technique that has become increasingly important in work with biological samples and pharmaceutical agents. This method is based on the use of a biologically-related agent as a stationary phase to selectively retain analytes or to study biological interactions. This review discusses the basic principles behind affinity chromatography and examines recent developments that have occurred in the use of this method for biomedical and pharmaceutical analysis. Techniques based on traditional affinity supports are discussed, but an emphasis is placed on methods in which affinity columns are used as part of HPLC systems or in combination with other analytical methods. General formats for affinity chromatography that are considered include step elution schemes, weak affinity chromatography, affinity extraction and affinity depletion. Specific separation techniques that are examined include lectin affinity chromatography, boronate affinity chromatography, immunoaffinity chromatography, and immobilized metal ion affinity chromatography. Approaches for the study of biological interactions by affinity chromatography are also presented, such as the measurement of equilibrium constants, rate constants, or competition and displacement effects. In addition, related developments in the use of immobilized enzyme reactors, molecularly imprinted polymers, dye ligands and aptamers are briefly considered. PMID:22305083

  13. Enrichment and characterization of phosphopeptides by immobilized metal affinity chromatography (IMAC) and mass spectrometry

    DEFF Research Database (Denmark)

    Thingholm, Tine E; Jensen, Ole N

    2009-01-01

    The combination of immobilized metal affinity chromatography (IMAC) and mass spectrometry is a widely used technique for enrichment and sequencing of phosphopeptides. In the IMAC method, negatively charged phosphate groups interact with positively charged metal ions (Fe3+, Ga3+, and Al3...

  14. Affinity monolith chromatography: A review of general principles and applications.

    Science.gov (United States)

    Li, Zhao; Rodriguez, Elliott; Azaria, Shiden; Pekarek, Allegra; Hage, David S

    2017-11-01

    Affinity monolith chromatography, or AMC, is a liquid chromatographic method in which the support is a monolith and the stationary phase is a biological-binding agent or related mimic. AMC has become popular for the isolation of biochemicals, for the measurement of various analytes, and for studying biological interactions. This review will examine the principles and applications of AMC. The materials that have been used to prepare AMC columns will be discussed, which have included various organic polymers, silica, agarose, and cryogels. Immobilization schemes that have been used in AMC will also be considered. Various binding agents and applications that have been reported for AMC will then be described. These applications will include the use of AMC for bioaffinity chromatography, immunoaffinity chromatography, dye-ligand affinity chromatography, and immobilized metal-ion affinity chromatography. The use of AMC with chiral stationary phases and as a tool to characterize biological interactions will also be examined. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Selection of imprinted nanoparticles by affinity chromatography.

    Science.gov (United States)

    Guerreiro, António R; Chianella, Iva; Piletska, Elena; Whitcombe, Michael J; Piletsky, Sergey A

    2009-04-15

    Soluble molecularly imprinted nanoparticles were synthesised via iniferter initiated polymerisation and separated by size via gel permeation chromatography. Subsequent fractionation of these particles by affinity chromatography allowed the separation of high affinity fractions from the mixture of nanoparticles. Fractions selected this way possess affinity similar to that of natural antibodies (K(d) 6.6x10(-8)) M and were also able to discriminate between related functional analogues of the template.

  16. Thin-layer chromatography of 49 metal ions on stannic antimonate in aqueous and mixed solvent systems containing dimethylsulfoxide: quantitative separation of uranium from numerous metal ions

    International Nuclear Information System (INIS)

    Qureshi, M.; Varshney, K.G.; Rajput, R.P.S.

    1976-01-01

    Thin-layer chromatography of 40 metal ions in 31 aqueous and mixed solvent systems has been performed on stannic antimonate ion-exchange material. Dimethylsulfoxide has been utilized to resolve such binary mixtures as La 3+ and Ce 3+ from Pr 3+ , Nd 3+ , and Sm 3+ ; VO 2+ from Ti 4+ , Nb 5+ , and Ta 5+ ; Ga 3+ from In 3+ , Tl + , and Y 3+ ; Fe 3+ from VO 2+ ; and Mg 2+ from Al 3+ . Quantitative separation of 200 to 800 μg U from its binary mixtures and from the synthetic mixtures containing Mg 2+ , Bi 3+ , Fe 3+ , Th 4+ , Ce 4+ , Cr 3+ , Zr 4+ , Hf 4+ , Ti 4+ Mn 2+ , Cu 2+ , Ce 3+ , In 3+ , Y 3+ , Ca 2+ , Co 2+ , Tl + , Nb 5+ , and Ag + has been obtained

  17. Affinity monolith chromatography: A review of principles and recent analytical applications

    Science.gov (United States)

    Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

    2012-01-01

    Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

  18. Metal ion-improved complexation countercurrent chromatography for enantioseparation of dihydroflavone enantiomers.

    Science.gov (United States)

    Han, Chao; Wang, Wenli; Xue, Guimin; Xu, Dingqiao; Zhu, Tianyu; Wang, Shanshan; Cai, Pei; Luo, Jianguang; Kong, Lingyi

    2018-01-12

    Cu(II) ion was selected as an additive to improve the enantioseparation efficiency of three dihydroflavone enantiomers in high-speed counter-current chromatography (HSCCC), using hydroxypropyl-β-cyclodextrin (HP-β-CyD) as the chiral selector. The influences of important parameters, including the metal ion, the concentrations of HP-β-CyD and the Cu(II) ion, and the sample size were investigated. Under optimal conditions, three dihydroflavone enantiomers, including (±)-hesperetin, (±)-naringenin, and (±)-farrerol, were successfully enantioseparated. The chiral recognition mechanism was investigated. The enantioseparation was attributed to the different thermodynamic stabilities of the binary complexes of HP-β-CyD and (±)-hesperetin, and Cu(II) ion could enhance this difference by forming ternary complexes with the binary complexes. This Cu(II) ion-improved complexation HSCCC system exhibited improved performance for chiral separation, and therefore it has great application potential in the preparative enantioseparation of other compounds with similar skeletons. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Compound immobilization and drug-affinity chromatography.

    Science.gov (United States)

    Rix, Uwe; Gridling, Manuela; Superti-Furga, Giulio

    2012-01-01

    Bioactive small molecules act through modulating a yet unpredictable number of targets. It is therefore of critical importance to define the cellular target proteins of a compound as an entry point to understanding its mechanism of action. Often, this can be achieved in a direct fashion by chemical proteomics. As with any affinity chromatography, immobilization of the bait to a solid support is one of the earliest and most crucial steps in the process. Interfering with structural features that are important for identification of a target protein will be detrimental to binding affinity. Also, many molecules are sensitive to heat or to certain chemicals, such as acid or base, and might be destroyed during the process of immobilization, which therefore needs to be not only efficient, but also mild. The subsequent affinity chromatography step needs to preserve molecular and conformational integrity of both bait compound and proteins in order to result in the desired specific enrichment while ensuring a high level of compatibility with downstream analysis by mass spectrometry. Thus, the right choice of detergent, buffer, and protease inhibitors is also essential. This chapter describes a widely applicable procedure for the immobilization of small molecule drugs and for drug-affinity chromatography with subsequent protein identification by mass spectrometry.

  20. Affinity of Smectite and Divalent Metal Ions (Mg(2+), Ca(2+), Cu(2+)) with L-leucine: An Experimental and Theoretical Approach Relevant to Astrobiology.

    Science.gov (United States)

    Pandey, Pramod; Pant, Chandra Kala; Gururani, Kavita; Arora, Priyanka; Pandey, Neetu; Bhatt, Preeti; Sharma, Yogesh; Negi, Jagmohan Singh; Mehata, Mohan Singh

    2015-12-01

    Earth is the only known planet bestowed with life. Several attempts have been made to explore the pathways of the origin of life on planet Earth. The search for the chemistry which gave rise to life has given answers related to the formation of biomonomers, and their adsorption on solid surfaces has gained much attention for the catalysis and stabilization processes related to the abiotic chemical evolution of the complex molecules of life. In this communication, surface interactions of L-leucine (Leu) on smectite (SMT) group of clay (viz. bentonite and montmorillonite) and their divalent metal ion (Mg(2+), Ca(2+) and Cu(2+)) incorporated on SMT has been studied to find the optimal conditions of time, pH, and concentration at ambient temperature (298 K). The progress of adsorption was followed spectrophotometrically and further characterized by FTIR, SEM/EDS and XRD. Leu, a neutral/non polar amino acid, was found to have more affinity in its zwitterionic form towards Cu(2+)- exchanged SMT and minimal affinity for Mg(2+)- exchanged SMT. The vibrational frequency shifts of -NH3 (+) and -COO(-) favor Van der Waal's forces during the course of surface interaction. Quantum calculations using density functional theory (DFT) have been applied to investigate the absolute value of metal ion affinities of Leu (Leu-M(2+) complex, M = Mg(2+), Ca(2+), Cu(2+)) with the help of their physico-chemical parameters. The hydration effect on the relative stability and geometry of the individual species of Leu-M(2+) × (H2O)n, (n =2 and 4) has also been evaluated within the supermolecule approach. Evidence gathered from investigations of surface interactions, divalent metal ions affinities and hydration effects with biomolecules may be important for better understanding of chemical evolution, the stabilization of biomolecules on solid surfaces and biomolecular-metal interactions. These results may have implications for understanding the origin of life and the preservation of

  1. Affinity capillary electrophoresis and density functional theory employed for the characterization of hexaarylbenzene-based receptor complexation with alkali metal ions

    Czech Academy of Sciences Publication Activity Database

    Ehala, Sille; Toman, Petr; Rathore, R.; Makrlík, E.; Kašička, Václav

    2011-01-01

    Roč. 32, č. 9 (2011), s. 981-987 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA203/08/1428; GA ČR(CZ) GA203/09/0675; GA ČR(CZ) GAP205/10/2280; GA AV ČR 1ET400500402 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40500505 Keywords : affinity capillary electrophoresis * alkali metal ions * binding constant Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.303, year: 2011

  2. Pseudo-affinity chromatography of rumen microbial cellulase on ...

    African Journals Online (AJOL)

    Pseudo-affinity chromatography of rumen microbial cellulase on Sepharose- Cibacron Blue F3GA. ... African Journal of Biotechnology ... Pseudo affinity adsorption of bioproducts on Sepharose-cibacron blue F3-GA was subjected to rumen microbial enzyme evaluation through batch binding and column chromatography of ...

  3. The application of transition metal ion chromatography to the determination of elemental and radiochemical species in PWR primary coolant

    International Nuclear Information System (INIS)

    Bridle, D.A.; Brown, G.R.; Johnson, P.A.V.

    1992-01-01

    The accurate determination of both elemental and radiochemical transition metal corrosion products, particularly cobalt and nickel, in PWR coolants is necessary if the transport mechanisms and their role in the development of out-of-core radiation fields are to be fully understood. AEA Technology, Winfrith, has collaborated for several years with a number of PWR utilities in Europe, developing advanced sampling and analytical techniques for the determination of both soluble and insoluble corrosion products in primary coolant. The design and installation of continuously flowing isokinetic capillary modifications to the existing sampling systems has been shown to be an effective method of providing a low, but representative, sample flow from high pressure systems for on-line determination of corrosion product species. Transition metal ion chromatography coupled with gamma-spectrometry has been used to determine both insoluble and soluble elemental and radiochemical species in reactor coolant, with particular attention being given to the determination of soluble elemental cobalt at levels as low as 1 ng per kg. Soluble species were determined directly following their concentration from up to 1 litre of coolant. Insoluble species collected on 0.45 micron filter membranes, following filtration of up to 1500 litres of coolant, were solubilised by fusion with potassium hydrogen sulphate before the application of ion chromatography. In each case the eluant from the chromatographic column was collected and the radionuclides determined by gamma-spectrometry

  4. Efficient fabrication of high-capacity immobilized metal ion affinity chromatographic media: The role of the dextran-grafting process and its manipulation.

    Science.gov (United States)

    Zhao, Lan; Zhang, Jingfei; Huang, Yongdong; Li, Qiang; Zhang, Rongyue; Zhu, Kai; Suo, Jia; Su, Zhiguo; Zhang, Zhigang; Ma, Guanghui

    2016-03-01

    Novel high-capacity Ni(2+) immobilized metal ion affinity chromatographic media were prepared through the dextran-grafting process. Dextran was grafted to an allyl-activated agarose-based matrix followed by functionalization for the immobilized metal ion affinity chromatographic media. With elaborate regulation of the allylation degree, dextran was completely or partly grafted to agarose microspheres, namely, completely dextran-grafted agarose microspheres and partly dextran-grafted ones, respectively. Confocal laser scanning microscope results demonstrated that a good adjustment of dextran-grafting degree was achieved, and dextran was distributed uniformly in whole completely dextran-grafted microspheres, while just distributed around the outside of the partly dextran-grafted ones. Flow hydrodynamic properties were improved greatly after the dextran-grafting process, and the flow velocity increased by about 30% compared with that of a commercial chromatographic medium (Ni Sepharose FF). A significant improvement of protein binding performance was also achieved by the dextran-grafting process, and partly dextran-grafted Ni(2+) chelating medium had a maximum binding capacity for His-tagged lactate dehydrogenase about 2.5 times higher than that of Ni Sepharose FF. The results indicated that this novel chromatographic medium is promising for applications in high-efficiency and large-scale protein purification. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. [Separation of osteoclasts by lectin affinity chromatography].

    Science.gov (United States)

    Itokazu, M; Tan, A; Tanaka, S

    1991-09-01

    Newborn rat calvaria bone cells obtained by digestion were fractionated on columns of wheat-germ agglutinin (WGA) sepharose 6MB for osteoclast isolation. The initial nonspecific binding cells which were passed through the WGA sepharose column by a buffer acquired a high enzyme activity of alkaline phosphatase, but not that of acid phosphatase. However, elution of cells using a buffer with the addition of N-acetyl-D-glucosamine resulted in a high acid phosphatase activity but no alkaline phosphatase activity. The former WGA binding negative fraction enriched osteoblasts averaging 30 microns in size. The latter WGA binding positive fraction enriched osteoclasts ranging from 20 microns to 60 microns in size. The electron-microscope clearly demonstrated the cellular details of osteoclasts. Isolated cell counts showed a ratio of six to four. These results indicate that our method of osteoclast isolation is simple and useful in lectin affinity chromatography because all cells have sugar moieties on their surface and the binding of osteoclasts can be reversed by the addition of specific lectin-binding sugars to the eluting buffer.

  6. Variation in one residue associated with the metal ion-dependent adhesion site regulates αIIbβ3 integrin ligand binding affinity.

    Directory of Open Access Journals (Sweden)

    Joel Raborn

    Full Text Available The Asp of the RGD motif of the ligand coordinates with the β I domain metal ion dependent adhesion site (MIDAS divalent cation, emphasizing the importance of the MIDAS in ligand binding. There appears to be two distinct groups of integrins that differ in their ligand binding affinity and adhesion ability. These differences may be due to a specific residue associated with the MIDAS, particularly the β3 residue Ala(252 and corresponding Ala in the β1 integrin compared to the analogous Asp residue in the β2 and β7 integrins. Interestingly, mutations in the adjacent to MIDAS (ADMIDAS of integrins α4β7 and αLβ2 increased the binding and adhesion abilities compared to the wild-type, while the same mutations in the α2β1, α5β1, αVβ3, and αIIbβ3 integrins demonstrated decreased ligand binding and adhesion. We introduced a mutation in the αIIbβ3 to convert this MIDAS associated Ala(252 to Asp. By combination of this mutant with mutations of one or two ADMIDAS residues, we studied the effects of this residue on ligand binding and adhesion. Then, we performed molecular dynamics simulations on the wild-type and mutant αIIbβ3 integrin β I domains, and investigated the dynamics of metal ion binding sites in different integrin-RGD complexes. We found that the tendency of calculated binding free energies was in excellent agreement with the experimental results, suggesting that the variation in this MIDAS associated residue accounts for the differences in ligand binding and adhesion among different integrins, and it accounts for the conflicting results of ADMIDAS mutations within different integrins. This study sheds more light on the role of the MIDAS associated residue pertaining to ligand binding and adhesion and suggests that this residue may play a pivotal role in integrin-mediated cell rolling and firm adhesion.

  7. Complexation ion-exchange chromatography of some metal ions on papers impregnated with Ti(IV)-based inorganic ion exchangers.

    Science.gov (United States)

    Sharma, S D; Gupta, R

    2000-02-01

    The chromatographic behavior of 40 metal ions is studied on titanium (IV) arsenate, titanium (IV) phosphate-, titanium (IV) molybdate-, titanium(IV) tungstate-, and titanium(IV) selenite-impregnated papers in 0.1M oxalic, citric, and tartaric acid as mobile phases. Similar studies are carried out on Whatman No. 1 papers for comparison. The ion-exchange capacity of these papers is determined, and their selectivity for different cations is discussed. The mechanism of migration is explained in terms of ion-exchange, precipitation, and adsorption. The prediction of elution sequence from RF values is also checked. The average Ri is found to be almost linearly dependent on the charge of the metal ions. The effect of the pKa of complexing acids on average RF values of 3d series metal ions is explained. A number of binary and ternary separations are achieved.

  8. Validation of ion chromatography for the determination of transition metal ions along with alkali, alkaline earth metal elements for uranium oxide fuel

    International Nuclear Information System (INIS)

    Kelkar, Anoop; Prakash, Amrit; Afzal, Mohd.; Panakkal, J.P.

    2009-02-01

    The present report describes the use of Ion chromatography (IC) methods with spectrophotometric and direct conductivity detection for the determination of transition metal elements and alkali alkaline earth metal ions in UO 2 pellets. Transmet analytical column and Metrosep- cation 1-2 column were used for the separation of transition metal elements and alkali and alkaline earth metal elements respectively. Oxalic acid and mixture of pyridine 2,6-dicarboxylic acid (PDCA), Na 2 SO 4 and NaCl were used as mobile phase for the separation of transition metal ions and monitored after post - column reaction with 4,2-pyridylazo resorcinol (PAR) at 520nm spectrophotometrically. In the determination of alkali and alkaline earth metal ions the interference of transition metals are removed by complexing them with PDCA. Mixture of tartaric acid and PDCA employed in the separation of alkali and alkaline earth metal ions and monitored on direct conductivity detector. Mobile phase composition was optimised for the base line separation. Calibration plots of Fe 3+ , Cu 2+ , Ni 2+ , Co 2+ , Cd 2+ , Mn 2+ , Li + , Na + , K + , Mg 2+ , Ca 2+ and Sr 2+ were linear over a wide dynamic range with regression coefficient better than 0.999. Detection limit of above ions were between 5-30ppb. To prevent the overloading of the cation exchange column, uranium matrix was removed from UO 2 sample by solvent extraction with 30% TBP - TOPO/CCl 4 . Ten sintered UO2 pellets of same lot were analysed and R.S.D. ±10% was obtained. These methods were validated by analysis of ILCE standards of UO 2 . (author)

  9. Indirect ultraviolet detection of alkaline earth metal ions using an imidazolium ionic liquid as an ultraviolet absorption reagent in ion chromatography.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2017-04-01

    A convenient and versatile method was developed for the separation and detection of alkaline earth metal ions by ion chromatography with indirect UV detection. The chromatographic separation of Mg 2+ , Ca 2+ , and Sr 2+ was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid as the mobile phase, in which the imidazolium ionic liquid acted as an UV-absorption reagent. The effects of imidazolium ionic liquids, detection wavelength, acids in the mobile phase, and column temperature on the retention of Mg 2+ , Ca 2+ , and Sr 2+ were investigated. The main factors influencing the separation and detection were the background UV absorption reagent and the concentration of hydrogen ion in ion chromatography with indirect UV detection. The successful separation and detection of Mg 2+ , Ca 2+ , and Sr 2+ within 14 min were achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.06, 0.12, and 0.23 mg/L, respectively. A new separation and detection method of alkaline earth metal ions by ion chromatography with indirect UV detection was developed, and the application range of ionic liquids was expanded. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Specific capture of uranyl protein targets by metal affinity chromatography

    International Nuclear Information System (INIS)

    Basset, C.; Dedieu, A.; Guerin, P.; Quemeneur, E.; Meyer, D.; Vidaud, C.

    2008-01-01

    To improve general understanding of biochemical mechanisms in the field of uranium toxicology, the identification of protein targets needs to be intensified. Immobilized metal affinity chromatography (IMAC) has been widely developed as a powerful tool for capturing metal binding proteins from biological extracts. However uranyl cations (UO 2 2+ ) have particular physico-chemical characteristics which prevent them from being immobilized on classical metal chelating supports. We report here on the first development of an immobilized uranyl affinity chromatography method, based on the cation-exchange properties of amino-phosphonate groups for uranyl binding. The cation distribution coefficient and loading capacity on the support were determined. Then the stability of the uranyl-bonded phase under our chromatographic conditions was optimized to promote affinity mechanisms. The successful enrichment of uranyl binding proteins from human serum was then proven using proteomic and mass spectral analysis. (authors)

  11. The Purification of a Blood Group A Glycoprotein: An Affinity Chromatography Experiment.

    Science.gov (United States)

    Estelrich, J.; Pouplana, R.

    1988-01-01

    Describes a purification process through affinity chromatography necessary to obtain specific blood group glycoproteins from erythrocytic membranes. Discusses the preparation of erythrocytic membranes, extraction of glycoprotein from membranes, affinity chromatography purification, determination of glycoproteins, and results. (CW)

  12. Chromatography of 49 metal ions on stannic antimonate papers in dimethylsulfoxide: nitric acid systems and aqueous nitric acid systems

    International Nuclear Information System (INIS)

    Qureshi, M.; Varshney, K.G.; Rajput, R.P.S.

    1975-01-01

    Chromatographic separations of 49 metal ions on stannic antimonate papers have been performed using mixed solvent systems containing DMSO. Aqueous HNO 3 systems have also been used. The utility of the papers has been demonstrated by achieving various difficult separations. Some of the important separations (R/sub f/ values given in parentheses) are: Cs + (0.20)-K + (0.30) and Sm 3+ (0.00)-Pr 3+ (0.72) in pure DMSO; Nb 5+ (0.14)-VO 2+ (0.95) in DMSO-6M HNO 3 (1:1); Ti 4+ (0.00)-VO 2 (0.97) in DMSO-0.5M HNO 3 (1:1); and Ba 2+ (0.06)-K + (0.52)-Sr 2+ (0.95), Ba 2+ (0.04)-Cs + (0.41)-Mg 2+ (0.93), and Ca 2+ (0.10)-Sr 2+ (0.94) in DMSO-0.1M HNO 3 (1:1). The time of development in each case is two hours. A discussion is presented on the dependence of Ri, log R/sub f/, and R/sub M/ on pH of the solvent to understand the mechanism of the movement of metal ions on papers impregnated with inorganic materials. (U.S.)

  13. Affinity chromatography: A versatile technique for antibody purification.

    Science.gov (United States)

    Arora, Sushrut; Saxena, Vikas; Ayyar, B Vijayalakshmi

    2017-03-01

    Antibodies continue to be extremely utilized entities in myriad applications including basic research, imaging, targeted delivery, chromatography, diagnostics, and therapeutics. At production stage, antibodies are generally present in complex matrices and most of their intended applications necessitate purification. Antibody purification has always been a major bottleneck in downstream processing of antibodies, due to the need of high quality products and associated high costs. Over the years, extensive research has focused on finding better purification methodologies to overcome this holdup. Among a plethora of different techniques, affinity chromatography is one of the most selective, rapid and easy method for antibody purification. This review aims to provide a detailed overview on affinity chromatography and the components involved in purification. An array of support matrices along with various classes of affinity ligands detailing their underlying working principles, together with the advantages and limitations of each system in purifying different types of antibodies, accompanying recent developments and important practical methodological considerations to optimize purification procedure are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Fatty acid and drug binding to a low-affinity component of human serum albumin, purified by affinity chromatography

    DEFF Research Database (Denmark)

    Vorum, H; Pedersen, A O; Honoré, B

    1992-01-01

    Binding equilibria for decanoate to a defatted, commercially available human serum albumin preparation were investigated by dialysis exchange rate determinations. The binding isotherm could not be fitted by the general binding equation. It was necessary to assume that the preparation was a mixture...... of two albumin components about 40% of the albumin having high affinity and about 60% having low affinity. By affinity chromatography we succeeded in purifying the low-affinity component from the mixture. The high-affinity component, however, could not be isolated. We further analyzed the fatty acid...... and drug binding abilities of the low-affinity component. The fatty acids decanoate, laurate, myristate and palmitate were bound with higher affinity to the mixture than to the low-affinity component. Diazepam was bound with nearly the same affinity to the low-affinity component as to the albumin mixture...

  15. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Immobilized palladium(II) ion affinity chromatography for recovery of recombinant proteins with peptide tags containing histidine and cysteine.

    Science.gov (United States)

    Kikot, Pamela; Polat, Aise; Achilli, Estefania; Fernandez Lahore, Marcelo; Grasselli, Mariano

    2014-11-01

    Fusion of peptide-based tags to recombinant proteins is currently one of the most used tools for protein production. Also, immobilized metal ion affinity chromatography (IMAC) has a huge application in protein purification, especially in research labs. The combination of expression systems of recombinant tagged proteins with this robust chromatographic system has become an efficient and rapid tool to produce milligram-range amounts of proteins. IMAC-Ni(II) columns have become the natural partners of 6xHis-tagged proteins. The Ni(II) ion is considered as the best compromise of selectivity and affinity for purification of a recombinant His-tagged protein. The palladium(II) ion is also able to bind to side chains of amino acids and form ternary complexes with iminodiacetic acid and free amino acids and other sulfur-containing molecules. In this work, we evaluated two different cysteine- and histidine-containing six amino acid tags linked to the N-terminal group of green fluorescent protein (GFP) and studied the adsorption and elution conditions using novel eluents. Both cysteine-containing tagged GFPs were able to bind to IMAC-Pd(II) matrices and eluted successfully using a low concentration of thiourea solution. The IMAC-Ni(II) system reaches less than 20% recovery of the cysteine-containing tagged GFP from a crude homogenate of recombinant Escherichia coli, meanwhile the IMAC-Pd(II) yields a recovery of 45% with a purification factor of 13. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Fundamental and practical studies on high-performance liquid affinity chromatography of biopolymers with novel stationary phases

    Energy Technology Data Exchange (ETDEWEB)

    Bacolod, M.D.

    1992-01-01

    Rigid microparticulate stationary phases having surface-bound metal chelating functions were developed and evaluated in high performance metal chelate affinity chromatography of proteins. Silica- and polystyrene-divinylbenzene-based metal chelate sorbents were produced in wide pore and in non-porous type of column packings. A major effort has been placed on development of non-porous highly crosslinked polystyrene-divinylbenzene (PSDVB). These PSDVB microparticles were produced by a two-step swelling polymerization, and exhibited excellent mechanical strength over a wide range of flow-rates and composition used in high performance liquid chromatography (HPLC). Simple and reproducible hydrophilic coatings were developed for the surface modification of hydrophobic PSDVB supports. A tetradentate metal chelating ligand, ethylenediamine-N, N[prime]-diacetic acid (EDDA), was covalently bound to the surface of the various supports. Sorbents having iminodiacetic acid (IDA) metal chelating functions were also evaluated. The hydrophilic character and surface coverage of various stationary phases were assessed chromatographically. Studies concerning the effects of eluent pH as well as the nature and concentration of salts on retention and selectivity with different metal chelate stationary phases having various immobilized metal ions were carried out. Elution schemes were developed for rapid separation of proteins in metal chelate affinity chromatography. EDDA stationary phases in metal forms can be viewed as complementary to IDA stationary phases since they afforded different selectivity and retentivity toward proteins. Hydrophilic PSDVB could be functionalized with IDA or EDDA metal chelating ligands or lectins. The non-porous metal chelate stationary phases afforded rapid separation of proteins by the development of multiple gradient systems, which permitted higher column peak capacity, enabling the separation of a greater number of proteins in a single chromatographic run.

  18. The Binding of Biotin to Sepharose-Avidin Column: Demonstration of the Affinity Chromatography Technique

    Science.gov (United States)

    Landman, A. D.; Landman, N. N.

    1976-01-01

    Describes a biochemistry experiment that illustrates the methodology of affinity chromatography by attaching avidin, a glycoprotein in egg white, to a Sepharose matrix in order to bind biotin-containing proteins. (MLH)

  19. Weak affinity chromatography for evaluation of stereoisomers in early drug discovery.

    Science.gov (United States)

    Duong-Thi, Minh-Dao; Bergström, Maria; Fex, Tomas; Svensson, Susanne; Ohlson, Sten; Isaksson, Roland

    2013-07-01

    In early drug discovery (e.g., in fragment screening), recognition of stereoisomeric structures is valuable and guides medicinal chemists to focus only on useful configurations. In this work, we concurrently screened mixtures of stereoisomers and estimated their affinities to a protein target (thrombin) using weak affinity chromatography-mass spectrometry (WAC-MS). Affinity determinations by WAC showed that minor changes in stereoisomeric configuration could have a major impact on affinity. The ability of WAC-MS to provide instant information about stereoselectivity and binding affinities directly from analyte mixtures is a great advantage in fragment library screening and drug lead development.

  20. Interaction of Hydroxyproline with Bivalent Metal Ions in Chemical ...

    African Journals Online (AJOL)

    NICO

    The stability constants of the ML and ML2 complex species of some metal ions, namely beryllium(II) and cobalt(II), with hydroxyproline were ... metal ions have several significant applications in biological systems.3–20 Beryllium is one ... 1 filter paper for chromatography was used for the purpose of electrophoresis. An Elico ...

  1. Mathematical analysis of frontal affinity chromatography in particle and membrane configurations.

    Science.gov (United States)

    Tejeda-Mansir, A; Montesinos, R M; Guzmán, R

    2001-10-30

    The scaleup and optimization of large-scale affinity-chromatographic operations in the recovery, separation and purification of biochemical components is of major industrial importance. The development of mathematical models to describe affinity-chromatographic processes, and the use of these models in computer programs to predict column performance is an engineering approach that can help to attain these bioprocess engineering tasks successfully. Most affinity-chromatographic separations are operated in the frontal mode, using fixed-bed columns. Purely diffusive and perfusion particles and membrane-based affinity chromatography are among the main commercially available technologies for these separations. For a particular application, a basic understanding of the main similarities and differences between particle and membrane frontal affinity chromatography and how these characteristics are reflected in the transport models is of fundamental relevance. This review presents the basic theoretical considerations used in the development of particle and membrane affinity chromatography models that can be applied in the design and operation of large-scale affinity separations in fixed-bed columns. A transport model for column affinity chromatography that considers column dispersion, particle internal convection, external film resistance, finite kinetic rate, plus macropore and micropore resistances is analyzed as a framework for exploring further the mathematical analysis. Such models provide a general realistic description of almost all practical systems. Specific mathematical models that take into account geometric considerations and transport effects have been developed for both particle and membrane affinity chromatography systems. Some of the most common simplified models, based on linear driving-force (LDF) and equilibrium assumptions, are emphasized. Analytical solutions of the corresponding simplified dimensionless affinity models are presented. Particular

  2. Frontal affinity chromatography: A unique research tool for biospecific interaction that promotes glycobiology

    Science.gov (United States)

    KASAI, Kenichi

    2014-01-01

    Combination of bioaffinity and chromatography gave birth to affinity chromatography. A further combination with frontal analysis resulted in creation of frontal affinity chromatography (FAC). This new versatile research tool enabled detailed analysis of weak interactions that play essential roles in living systems, especially those between complex saccharides and saccharide-binding proteins. FAC now becomes the best method for the investigation of saccharide-binding proteins (lectins) from viewpoints of sensitivity, accuracy, and efficiency, and is contributing greatly to the development of glycobiology. It opened a door leading to deeper understanding of the significance of saccharide recognition in life. The theory is also concisely described. PMID:25169774

  3. Metal ion transporters and homeostasis.

    OpenAIRE

    Nelson, N

    1999-01-01

    Transition metals are essential for many metabolic processes and their homeostasis is crucial for life. Aberrations in the cellular metal ion concentrations may lead to cell death and severe diseases. Metal ion transporters play a major role in maintaining the correct concentrations of the various metal ions in the different cellular compartments. Recent studies of yeast mutants revealed key elements in metal ion homeostasis, including novel transport systems. Several of the proteins discover...

  4. Cereal n-glycoproteins enrichment by lectin affinity monolithic chromatography

    Czech Academy of Sciences Publication Activity Database

    Flodrová, Dana; Bobálová, Janette; Laštovičková, Markéta

    2016-01-01

    Roč. 44, č. 2 (2016), s. 286-297 ISSN 0133-3720 R&D Projects: GA ČR(CZ) GPP503/12/P395 Institutional support: RVO:68081715 Keywords : barley * wheat * glycoprotein * mass spectrometry * lectin chromatography Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.496, year: 2016

  5. Supramolecular Affinity Chromatography for Methylation-Targeted Proteomics.

    Science.gov (United States)

    Garnett, Graham A E; Starke, Melissa J; Shaurya, Alok; Li, Janessa; Hof, Fraser

    2016-04-05

    Proteome-wide studies of post-translationally methylated species using mass spectrometry are complicated by high sample diversity, competition for ionization among peptides, and mass redundancies. Antibody-based enrichment has powered methylation proteomics until now, but the reliability, pan-specificity, polyclonal nature, and stability of the available pan-specific antibodies are problematic and do not provide a standard, reliable platform for investigators. We have invented an anionic supramolecular host that can form host-guest complexes selectively with methyllysine-containing peptides and used it to create a methylysine-affinity column. The column resolves peptides on the basis of methylation-a feat impossible with a comparable commercial cation-exchange column. A proteolyzed nuclear extract was separated on the methyl-affinity column prior to standard proteomics analysis. This experiment demonstrates that such chemical methyl-affinity columns are capable of enriching and improving the analysis of methyllysine residues from complex protein mixtures. We discuss the importance of this advance in the context of biomolecule-driven enrichment methods.

  6. Analysis of Biological Interactions by Affinity Chromatography: Clinical and Pharmaceutical Applications.

    Science.gov (United States)

    Hage, David S

    2017-06-01

    The interactions between biochemical and chemical agents in the body are important in many clinical processes. Affinity chromatography and high-performance affinity chromatography (HPAC), in which a column contains an immobilized biologically related binding agent, are 2 methods that can be used to study these interactions. This review presents various approaches that can be used in affinity chromatography and HPAC to characterize the strength or rate of a biological interaction, the number and types of sites that are involved in this process, and the interactions between multiple solutes for the same binding agent. A number of applications for these methods are examined, with an emphasis on recent developments and high-performance affinity methods. These applications include the use of these techniques for fundamental studies of biological interactions, high-throughput screening of drugs, work with modified proteins, tools for personalized medicine, and studies of drug-drug competition for a common binding agent. The wide range of formats and detection methods that can be used with affinity chromatography and HPAC for examining biological interactions makes these tools attractive for various clinical and pharmaceutical applications. Future directions in the development of small-scale columns and the coupling of these methods with other techniques, such as mass spectrometry or other separation methods, should continue to increase the flexibility and ease with which these approaches can be used in work involving clinical or pharmaceutical samples. © 2016 American Association for Clinical Chemistry.

  7. Fungitoxicity of metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Somers, E

    1961-01-01

    The in vitro fungistatic activity of some twenty-four metal cations has been determine against Alternaria tenuis and Botrytis fabae. The metal salts, mainly nitrates, were tested in aqueous solution without added spore germination stimulant. The logarithm of the metal ion concentration at the ED 50 value has been found to conform to the exponenttial relationship with electronegativity proposed by Danielli and Davies (1951). These results are discussed in relation to the site of action of metal cations on the fungal cell.

  8. APPLICATION OF IMMUNOGLOBULIN-BINDING PROTEINS A, G, L IN THE AFFINITY CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    О. V. Sviatenko

    2014-04-01

    Full Text Available Proteins A, G and L are native or recombinant proteins of microbial origin that bind to mammalian immunoglobulins. Preferably recombinant variants of proteins A, G, L are used in biotechnology for affinity sorbents production. Сomparative characteristics of proteins A, G, L and affinity sorbents on the basis of them, advantages and disadvantages of these proteins application as ligands in the affinity chromatography are done. Analysis of proteins A, G, L properties is presented. Binding specificities and affinities of these proteins differ between species and antibody subclass. Protein А has high affinity to human IgG1, IgG2, IgG4, mouse IgG2a, IgG2b, IgG3, goat and sheep IgG2, dog, cat, guinea pig, rabbit IgG. Protein G binds strongly to human, mouse, cow, goat, sheep and rabbit IgG. Protein L has ability of strong binding to immunoglobulin kappa-chains of human, mouse, rat and pig. Expediency of application of affinity chromatography with usage of sorbents on the basis of immobilized proteins A, G, L are shown for isolation and purification of antibodies different classes. Previously mentioned method is used as an alternative to conventional methods of protein purification, such as ion-exchange, hydrophobic interactions, metal affinity chromatography, ethanol precipitation due to simplicity in usage, possibility of one-step purification process, obtaining of proteins high level purity, multiuse at maintenance of proper storage and usage conditions. Affinity sorbents on the basis of immobilized proteins A, G, L are used not only for antibodies purification, but also for extraction of different antibodies fractions from blood serum.

  9. Application of coupled affinity-sizing chromatography for the detection of proteolyzed HSA-tagged proteins.

    Science.gov (United States)

    London, Anne Serdakowski; Patel, Kunal; Quinn, Lisa; Lemmerer, Martin

    2015-04-01

    Coupled affinity liquid chromatography and size exclusion chromatography (ALC-SEC) is a technique that has been shown to successfully report product quality of proteins during cell expression and prior to the commencement of downstream processing chromatography steps. This method was applied to monitoring the degradation and subsequent partial remediation of a HSA-tagged protein which showed proteolysis, allowing for rapid cell line development to address this product quality dilemma. This paper outlines the novel application of this method for measuring and addressing protease-induced proteolysis. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Purification of infectious canine parvovirus from cell culture by affinity chromatography with monoclonal antibodies.

    NARCIS (Netherlands)

    J. Groen (Jan); N. Juntti; J.S. Teppema; F.G.C.M. Uytdehaag (Fons); A.D.M.E. Osterhaus (Albert); G.F. Rimmelzwaan (Guus)

    1987-01-01

    textabstractImmuno affinity chromatography with virus neutralizing monoclonal antibodies, directed to the haemagglutinating protein of canine parvovirus (CPV) was used to purify and concentrate CPV from infected cell culture. The procedure was monitored by testing the respective fractions in an

  11. Characterization of the human cerebrospinal fluid phosphoproteome by titanium dioxide affinity chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Bahl, Justyna Maria Czarna; Jensen, Søren Skov; Larsen, Martin R

    2008-01-01

    of phosphorylation aberrations in health and disease. Toward that goal we here describe a method for a comprehensive isolation and identification of phosphorylated tryptic peptides derived from CSF proteins using a simple sample preparation step and titanium dioxide-affinity chromatography followed by MALDI...

  12. Displacement affinity chromatography of protein phosphatase one (PP1 complexes

    Directory of Open Access Journals (Sweden)

    Gourlay Robert

    2008-11-01

    Full Text Available Abstract Background Protein phosphatase one (PP1 is a ubiquitously expressed, highly conserved protein phosphatase that dephosphorylates target protein serine and threonine residues. PP1 is localized to its site of action by interacting with targeting or regulatory proteins, a majority of which contains a primary docking site referred to as the RVXF/W motif. Results We demonstrate that a peptide based on the RVXF/W motif can effectively displace PP1 bound proteins from PP1 retained on the phosphatase affinity matrix microcystin-Sepharose. Subsequent co-immunoprecipitation experiments confirmed that each identified binding protein was either a direct PP1 interactor or was in a complex that contains PP1. Our results have linked PP1 to numerous new nuclear functions and proteins, including Ki-67, Rif-1, topoisomerase IIα, several nuclear helicases, NUP153 and the TRRAP complex. Conclusion This modification of the microcystin-Sepharose technique offers an effective means of purifying novel PP1 regulatory subunits and associated proteins and provides a simple method to uncover a link between PP1 and additional cellular processes.

  13. High Performance Affinity Chromatography of Antithrombin III Based on Monodisperse Poly (glycidyl methacrylate) Beads

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new approach for the separation of antithrombin III with high performance affinity chromatography (HPAC) was described. A novel monodisperse,non-porous,cross-linked poly (glycidyl methacrylate) beads (PGMA) were used as the affinity support. With the water-soluble carbodiimide,heparin was linked covalently to amino-PGMA-beads,which was prepared by amination of PGMA. The adsorbent obtained exhibits high binding activity to antithrombin III (ATIII),good resolution and excellent mechanical properties and can be used under high flow rate.

  14. Glycoproteins of axonal transport: affinity chromatography on fucose-specific lectins

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, S.; Ohlson, C.; Karlsson, J.O.

    1982-03-01

    Rapidly transported fucose-labeled glycoproteins from axons of rabbit retinal ganglion cells were solubilized with nonionic detergents. The solubilized components were subjected to affinity chromatography on three different fucose-specific lectins. A recently characterized fucose-specific lectin from Aleuria aurantia bound reversibly approximately 60% of the applied protein-bound radioactivity. The lectins from Lotus tetragonolobus and Ulex europaeus bound are very small proportions of the labeled rapidly transported glycoproteins.

  15. Optimising the design and operation of semi-continuous affinity chromatography for clinical and commercial manufacture.

    Science.gov (United States)

    Pollock, James; Bolton, Glen; Coffman, Jon; Ho, Sa V; Bracewell, Daniel G; Farid, Suzanne S

    2013-04-05

    This paper presents an integrated experimental and modelling approach to evaluate the potential of semi-continuous chromatography for the capture of monoclonal antibodies (mAb) in clinical and commercial manufacture. Small-scale single-column experimental breakthrough studies were used to derive design equations for the semi-continuous affinity chromatography system. Verification runs with the semi-continuous 3-column and 4-column periodic counter current (PCC) chromatography system indicated the robustness of the design approach. The product quality profiles and step yields (after wash step optimisation) achieved were comparable to the standard batch process. The experimentally-derived design equations were incorporated into a decisional tool comprising dynamic simulation, process economics and sizing optimisation. The decisional tool was used to evaluate the economic and operational feasibility of whole mAb bioprocesses employing PCC affinity capture chromatography versus standard batch chromatography across a product's lifecycle from clinical to commercial manufacture. The tool predicted that PCC capture chromatography would offer more significant savings in direct costs for early-stage clinical manufacture (proof-of-concept) (∼30%) than for late-stage clinical (∼10-15%) or commercial (∼5%) manufacture. The evaluation also highlighted the potential facility fit issues that could arise with a capture resin (MabSelect) that experiences losses in binding capacity when operated in continuous mode over lengthy commercial campaigns. Consequently, the analysis explored the scenario of adopting the PCC system for clinical manufacture and switching to the standard batch process following product launch. The tool determined the PCC system design required to operate at commercial scale without facility fit issues and with similar costs to the standard batch process whilst pursuing a process change application. A retrofitting analysis established that the direct cost

  16. Analytical FcRn affinity chromatography for functional characterization of monoclonal antibodies

    Science.gov (United States)

    Schlothauer, Tilman; Rueger, Petra; Stracke, Jan Olaf; Hertenberger, Hubert; Fingas, Felix; Kling, Lothar; Emrich, Thomas; Drabner, Georg; Seeber, Stefan; Auer, Johannes; Koch, Stefan; Papadimitriou, Apollon

    2013-01-01

    The neonatal Fc receptor (FcRn) is important for the metabolic fate of IgG antibodies in vivo. Analysis of the interaction between FcRn and IgG in vitro might provide insight into the structural and functional integrity of therapeutic IgG that may affect pharmacokinetics (PK) in vivo. We developed a standardized pH gradient FcRn affinity liquid chromatography method with conditions closely resembling the physiological mechanism of interaction between IgG and FcRn. This method allows the separation of molecular IgG isoforms, degradation products and engineered molecules based on their affinity to FcRn. Human FcRn was immobilized on the column and a linear pH gradient from pH 5.5 to 8.8 was applied. FcRn chromatography was used in comparison to surface plasmon resonance to characterize different monoclonal IgG preparations, e.g., oxidized or aggregated species. Wild-type and engineered IgGs were compared in vitro by FcRn chromatography and in vivo by PK studies in huFcRn transgenic mice. Analytical FcRn chromatography allows differentiation of IgG samples and variants by peak pattern and retention time profile. The method can distinguish: 1) IgGs with different Fabs, 2) oxidized from native IgG, 3) aggregates from monomer and 4) antibodies with mutations in the Fc part from wild-type IgGs. Changes in the FcRn chromatographic behavior of mutant IgGs relative to the wild-type IgG correlate to changes in the PK profile in the FcRn transgenic mice. These results demonstrate that FcRn affinity chromatography is a useful new method for the assessment of IgG integrity. PMID:23765230

  17. A new biotechnology for recovering heavy metal ions from wastewater

    International Nuclear Information System (INIS)

    Darnall, D.W.; Gabel, A.

    1989-01-01

    This paper reports that bio-recovery systems has developed a new sorption process for removing toxic metal ions from water. This process is based upon the natural, very strong affinity for biological materials, such as the cell walls of plants and microorganisms, for heavy metal ions such as uranium, cadmium, cobalt, nickel, etc.. Biological materials, primarily algae, have been immobilized in a polymer to produce a biological ion exchange resin, AlgaSORB. The material has a remarkable affinity for heavy metal ions and is capable of concentrating these ions by a factor of may thousand-fold. Additionally, the bound metals can be stripped and recovered from the algal material in a manner similar to conventional resins

  18. Characteristics of the interaction of calcium with casein submicelles as determined by analytical affinity chromatography

    International Nuclear Information System (INIS)

    Jang, H.D.; Swaisgood, H.E.

    1990-01-01

    Interaction of calcium with casein submicelles was investigated in CaCl2 and calcium phosphate buffers and with synthetic milk salt solutions using the technique of analytical affinity chromatography. Micelles that had been prepared by size exclusion chromatography with glycerolpropyl controlled-pore glass from fresh raw skim milk that had never been cooled, were dialyzed at room temperature against calcium-free imidazole buffer, pH 6.7. Resulting submicelles were covalently immobilized on succinamidopropyl controlled-pore glass (300-nm pore size). Using 45Ca to monitor the elution retardation, the affinity of free Ca2+ and calcium salt species was determined at temperatures of 20 to 40 degrees C and pH 6.0 to 7.5. Increasing the pH in this range or increasing the temperature strengthened the binding of calcium to submicelles, similar to previous observations with individual caseins. However, the enthalpy change obtained from the temperature dependence was considerably greater than that reported for alpha s1- and beta-caseins. Furthermore, the elution profiles for 45Ca in milk salt solutions were decidedly different from those in CaCl2 or calcium phosphate buffers and the affinities were also greater. For example, at pH 6.7 and 30 degrees C the average dissociation constant for the submicelle-calcium complex is 0.074 mM for CaCl2 and calcium phosphate buffers, vs 0.016 mM for the milk salt solution. The asymmetric frontal boundaries and higher average affinities observed with milk salts may be due to binding of calcium salts with greater affinity in addition to the binding of free Ca2+ in these solutions

  19. Aflatoxin metabolism in humans: detection of metabolites and nucleic acid adducts in urine by affinity chromatography

    International Nuclear Information System (INIS)

    Groopman, J.D.; Donahue, P.R.; Zhu, J.Q.; Chen, J.S.; Wogan, G.N.

    1985-01-01

    A high-affinity IgM monoclonal antibody specific for aflatoxins was covalently bound to Sepharose 4B and used as a preparative column to isolate aflatoxin derivatives from the urine of people and experimental animals who had been exposed to the carcinogen environmentally or under laboratory conditions. Aflatoxin levels were quantified by radioimmunoassay and high-performance liquid chromatography after elution from the affinity column. In studies on rats injected with [ 14 C]aflatoxin B1, the authors identified the major aflatoxin-DNA adduct, 2,3-dihydro-2-(N7-guanyl)-3-hydroxy-aflatoxin B1 (AFB1-N7-Gua), and the oxidative metabolites M1 and P1 as the major aflatoxin species present in the urine. When this methodology was applied to human urine samples obtained from people from the Guangxi Province of China exposed to aflatoxin B1 through dietary contamination, the aflatoxin metabolites detected were also AFB1-N7-Gua and aflatoxins M1 and P1. Therefore, affinity chromatography using a monoclonal antibody represents a useful and rapid technique with which to isolate this carcinogen and its metabolites in biochemical epidemiology and for subsequent quantitative measurements, providing exposure information that can be used for risk assessment

  20. Fractionation of Aspergillus niger cellulases by combined ion exchange affinity chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, R.F.; Allen, T.L.; Dykema, P.A.

    1987-02-05

    Eight chemically modified cellulose supports were tested for their ability to adsorb components of the Aspergillus niger cellulase system. At least two of the most effective adsorbents, aminoethyl cellulose and carboxymethyl cellulose, were shown to be useful for the fractionation of cellulases. These supports apparently owe their resolving capacity to both ion exchange and biospecific binding effects; however, the relative importance of each effect is unknown. These observations form the basis for a new cellulase fractionation technique, combined ion exchange-affinity chromatography. 22 references.

  1. Determination of residual fluoroquinolones in honey by liquid chromatography using metal chelate affinity chromatography.

    Science.gov (United States)

    Yatsukawa, Yoh-Ichi; Ito, Hironobu; Matsuda, Takahiro; Nakamura, Munetomo; Watai, Masatoshi; Fujita, Kazuhiro

    2011-01-01

    A new analytical method for the simultaneous determination of seven fluoroquinolones, namely, norfloxacin, ciprofloxacin, danofloxacin, enrofloxacin, orbifloxacin, sarafloxacin, and difloxacin, especially in dark-colored honey, has been developed. Fluoroquinolone antibiotics were extracted from samples with MacIlvaine buffer solution (pH 4.0) containing EDTA disodium salt dihydrate. The extracts were treated with both a polymeric cartridge and a metal chelate affinity column preloaded with ferric ion (Fe3+). LC separation with fluorescence detection was performed at 40 degrees C using an Inertsil ODS-4 analytical column (150 x 4.6 mm, 3 microm). The mobile phase was composed of 20 mM/L citrate buffer solution (pH 3.1)-acetonitrile mixture (70 + 30, v/v) containing 1 mM/L sodium dodecyl sulfate. Lomefloxacin was used as an internal standard. The developed method was validated according to the criteria of European Commission Decision 2002/657/EC. Decision limits and detection capabilities were below 2.9 and 4.4 microg/kg, respectively.

  2. Hydrophilic Nb{sup 5+}-immobilized magnetic core–shell microsphere – A novel immobilized metal ion affinity chromatography material for highly selective enrichment of phosphopeptides

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xueni; Liu, Xiaodan; Feng, Jianan [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China); Li, Yan, E-mail: yanli@fudan.edu.cn [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China); Deng, Chunhui [Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433 (China); Duan, Gengli [Pharmaceutical Analysis Department, School of Pharmacy, Fudan University, Shanghai 201203 (China)

    2015-06-23

    Highlights: • A new IMAC material (Fe{sub 3}O{sub 4}@PD-Nb{sup 5+}) was synthesized. • The strong magnetic behaviors of the microspheres ensure fast and easy separation. • The enrichment ability was tested by human serum and nonfat milk. • The results were compared with other IMAC materials including the commercial kits. • All results proved the good enrichment ability, especially for multiphosphopeptides. - Abstract: Rapid and selective enrichment of phosphopeptides from complex biological samples is essential and challenging in phosphorylated proteomics. In this work, for the first time, niobium ions were directly immobilized on the surface of polydopamine-coated magnetic microspheres through a facile and effective synthetic route. The Fe{sub 3}O{sub 4}@polydopamine-Nb{sup 5+} (denoted as Fe{sub 3}O{sub 4}@PD-Nb{sup 5+}) microspheres possess merits of high hydrophilicity and good biological compatibility, and demonstrated low limit of detection (2 fmol). The selectivity was also basically satisfactory (β-casein:BSA = 1:500) to capture phosphopeptides. They were also successfully applied for enrichment of phosphopeptides from real biological samples such as human serum and nonfat milk. Compared with Fe{sub 3}O{sub 4}@PD-Ti{sup 4+} microspheres, the Fe{sub 3}O{sub 4}@PD-Nb{sup 5+} microspheres exhibit superior selectivity to multi-phosphorylated peptides, and thus may be complementary to the conventional IMAC materials.

  3. In-column ATR-FTIR spectroscopy to monitor affinity chromatography purification of monoclonal antibodies

    Science.gov (United States)

    Boulet-Audet, Maxime; Kazarian, Sergei G.; Byrne, Bernadette

    2016-01-01

    In recent years many monoclonal antibodies (mAb) have entered the biotherapeutics market, offering new treatments for chronic and life-threatening diseases. Protein A resin captures monoclonal antibody (mAb) effectively, but the binding capacity decays over repeated purification cycles. On an industrial scale, replacing fouled Protein A affinity chromatography resin accounts for a large proportion of the raw material cost. Cleaning-in-place (CIP) procedures were developed to extend Protein A resin lifespan, but chromatograms cannot reliably quantify any remaining contaminants over repeated cycles. To study resin fouling in situ, we coupled affinity chromatography and Fourier transform infrared (FTIR) spectroscopy for the first time, by embedding an attenuated total reflection (ATR) sensor inside a micro-scale column while measuring the UV 280 nm and conductivity. Our approach quantified the in-column protein concentration in the resin bed and determined protein conformation. Our results show that Protein A ligand leached during CIP. We also found that host cell proteins bound to the Protein A resin even more strongly than mAbs and that typical CIP conditions do not remove all fouling contaminants. The insights derived from in-column ATR-FTIR spectroscopic monitoring could contribute to mAb purification quality assurance as well as guide the development of more effective CIP conditions to optimise resin lifespan. PMID:27470880

  4. In-column ATR-FTIR spectroscopy to monitor affinity chromatography purification of monoclonal antibodies

    Science.gov (United States)

    Boulet-Audet, Maxime; Kazarian, Sergei G.; Byrne, Bernadette

    2016-07-01

    In recent years many monoclonal antibodies (mAb) have entered the biotherapeutics market, offering new treatments for chronic and life-threatening diseases. Protein A resin captures monoclonal antibody (mAb) effectively, but the binding capacity decays over repeated purification cycles. On an industrial scale, replacing fouled Protein A affinity chromatography resin accounts for a large proportion of the raw material cost. Cleaning-in-place (CIP) procedures were developed to extend Protein A resin lifespan, but chromatograms cannot reliably quantify any remaining contaminants over repeated cycles. To study resin fouling in situ, we coupled affinity chromatography and Fourier transform infrared (FTIR) spectroscopy for the first time, by embedding an attenuated total reflection (ATR) sensor inside a micro-scale column while measuring the UV 280 nm and conductivity. Our approach quantified the in-column protein concentration in the resin bed and determined protein conformation. Our results show that Protein A ligand leached during CIP. We also found that host cell proteins bound to the Protein A resin even more strongly than mAbs and that typical CIP conditions do not remove all fouling contaminants. The insights derived from in-column ATR-FTIR spectroscopic monitoring could contribute to mAb purification quality assurance as well as guide the development of more effective CIP conditions to optimise resin lifespan.

  5. Heavy metal ion adsorption onto polypyrrole-impregnated porous carbon.

    Science.gov (United States)

    Choi, Moonjung; Jang, Jyongsik

    2008-09-01

    Polypyrrole-impregnated porous carbon was readily synthesized using vapor infiltration polymerization of pyrrole monomers. The results show that the functionalized polymer layer was successfully coated onto the pore surface of carbon without collapse of mesoporous structure. The modified porous carbon exhibited an improved complexation affinity for heavy metal ions such as mercury, lead, and silver ions due to the amine group of polypyrrole. The introduced polypyrrole layer could provide the surface modification to be applied for heavy metal ion adsorbents. Especially, polymer-impregnated porous carbon has an enhanced heavy metal ion uptake, which is 20 times higher than that of adsorbents with amine functional groups. Furthermore, the relationship between the coated polymer amount and surface area was also investigated in regard to adsorption capacity.

  6. Heavy metal ions are potent inhibitors of protein folding

    International Nuclear Information System (INIS)

    Sharma, Sandeep K.; Goloubinoff, Pierre; Christen, Philipp

    2008-01-01

    Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd 2+ , Hg 2+ and Pb 2+ proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC 50 in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far

  7. Fragment screening for drug leads by weak affinity chromatography (WAC-MS).

    Science.gov (United States)

    Ohlson, Sten; Duong-Thi, Minh-Dao

    2018-02-23

    Fragment-based drug discovery is an important tool for design of small molecule hit-to-lead compounds against various biological targets. Several approved drugs have been derived from an initial fragment screen and many such candidates are in various stages of clinical trials. Finding fragment hits, that are suitable for optimisation by medicinal chemists, is still a challenge as the binding between the small fragment and its target is weak in the range of mM to µM of K d and irrelevant non-specific interactions are abundant in this area of transient interactions. Fortunately, there are methods that can study weak interactions quite efficiently of which NMR, surface plasmon resonance (SPR) and X-ray crystallography are the most prominent. Now, a new technology based on zonal affinity chromatography, weak affinity chromatography (WAC), has been introduced which has remedied many of the problems with other technologies. By combining WAC with mass spectrometry (WAC-MS), it is a powerful tool to identify binders quantitatively in terms of affinity and kinetics either from fragment libraries or from complex mixtures of biological extracts. As WAC-MS can be multiplexed by analysing mixtures of fragments (20-100 fragments) in one sample, this approach yields high throughput, where a whole library of e.g. >2000 fragments can be analysed quantitatively within a day. WAC-MS is easy to perform, where the robustness and quality of HPLC is fully utilized. This review will highlight the rationale behind the application of WAC-MS for fragment screening in drug discovery. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Fragment screening of cyclin G-associated kinase by weak affinity chromatography.

    Science.gov (United States)

    Meiby, Elinor; Knapp, Stefan; Elkins, Jonathan M; Ohlson, Sten

    2012-11-01

    Fragment-based drug discovery (FBDD) has become a new strategy for drug discovery where lead compounds are evolved from small molecules. These fragments form low affinity interactions (dissociation constant (K(D)) = mM - μM) with protein targets, which require fragment screening methods of sufficient sensitivity. Weak affinity chromatography (WAC) is a promising new technology for fragment screening based on selective retention of fragments by a drug target. Kinases are a major pharmaceutical target, and FBDD has been successfully applied to several of these targets. In this work, we have demonstrated the potential to use WAC in combination with mass spectrometry (MS) detection for fragment screening of a kinase target-cyclin G-associated kinase (GAK). One hundred seventy fragments were selected for WAC screening by virtual screening of a commercial fragment library against the ATP-binding site of five different proteins. GAK protein was immobilized on a capillary HPLC column, and compound binding was characterized by frontal affinity chromatography. Compounds were screened in sets of 13 or 14, in combination with MS detection for enhanced throughput. Seventy-eight fragments (46 %) with K(D) < 200 μM were detected, including a few highly efficient GAK binders (K(D) of 2 μM; ligand efficiency = 0.51). Of special interest is that chiral screening by WAC may be possible, as two stereoisomeric fragments, which both contained one chiral center, demonstrated twin peaks. This ability, in combination with the robustness, sensitivity, and simplicity of WAC makes it a new method for fragment screening of considerable potential.

  9. CMPO-functionalized C{sub 3}-symmetric tripodal ligands in liquid/liquid extractions : efficient, selective recognition of Pu(IV) with low affinity for 3+ metal ions.

    Energy Technology Data Exchange (ETDEWEB)

    Matloka, K.; Sah, A. K.; Peters, M. W.; Srinivasan, P.; Gelis, A. V.; Regalbuto, M.; Scott, M. J.; Univ. of Florida

    2007-12-10

    Structural modifications of carbamoylmethylphosphine oxide (CPMO)-functionalized triphenoxymethane platforms are described, and the influence of these changes on the ability of the ligand to extract actinides from simulated acidic nuclear waste streams has been evaluated. The ligand system has been shown to have excellent binding efficiency and a selectivity for An(IV) in comparison to the a simple monomeric CMPO ligand under analogous conditions. Both the extraction efficiency and selectivity are strongly dependent on the flexibility and electronic properties of the ligating units in the triphenoxymethane construct. The Tb(III) and Bi(III) nitrate complexes of tris-CMPO derivatives have been isolated, and their structures were elucidated by NMR, ESI FT-ICR MS, and X-ray analysis, providing information on the interactions between metal ions and the tris-CMPO molecules.

  10. PVA-Glutaraldehyde as support for lectin immobilization and affinity chromatography

    Directory of Open Access Journals (Sweden)

    Moacyr Jesus Barreto de Melo Rêgo

    2016-12-01

    Full Text Available Immobilized lectins are a powerful biotechnological tool for separation and isolation of glycoconjugates. In the present study, polyvinyl alcohol (PVA and glutaraldehyde (GA were used as a support for Concanavalin A (Con A covalent immobilization and for entrapment of Parkia pendula seed gum (PpeG. Con A immobilization yielded approximately 30% and 0.6 M glucose solution was the minimum concentration able to elute fetuin from column. PVA-GA-PpeG column was efficiently recognized by pure P. pendula lectin (PpeL. These findings indicate that PVA-GA interpenetrated network showed to be an efficient support for lectin covalent immobilization and as affinity chromatography matrix after trapping of PpeG.

  11. Purification and characterization of a new type lactose-binding Ulex europaeus lectin by affinity chromatography.

    Science.gov (United States)

    Konami, Y; Yamamoto, K; Osawa, T

    1991-02-01

    A new type lactose-binding lectin was purified from extracts of Ulex europaeus seeds by affinity chromatography on a column of galactose-Sepharose 4B, followed by gel filtration on Sephacryl S-300. This lectin, designated as Ulex europaeus lectin III (UEA-III), was found to be inhibited by lactose. The dimeric lectin is a glycoprotein with a molecular mass of 70,000 Da; it consists of two apparently identical subunits of a molecular mass of 34,000 Da. Compositional analysis showed that this lectin contains 30% carbohydrate and a large amount of aspartic acid, serine and valine, but no sulfur-containing amino acids. The N-terminal amino-acid sequences of L-fucose-binding Ulex europaeus lectin I (UEA-I) and di-N-acetylchitobiose-binding Ulex europaeus lectin II (UEA-II), both of which we have already purified and characterized, and that of UEA-III were determined and compared.

  12. Immobilized metal-affinity chromatography protein-recovery screening is predictive of crystallographic structure success

    International Nuclear Information System (INIS)

    Choi, Ryan; Kelley, Angela; Leibly, David; Nakazawa Hewitt, Stephen; Napuli, Alberto; Van Voorhis, Wesley

    2011-01-01

    An overview of the methods used for high-throughput cloning and protein-expression screening of SSGCID hexahistidine recombinant proteins is provided. It is demonstrated that screening for recombinant proteins that are highly recoverable from immobilized metal-affinity chromatography improves the likelihood that a protein will produce a structure. The recombinant expression of soluble proteins in Escherichia coli continues to be a major bottleneck in structural genomics. The establishment of reliable protocols for the performance of small-scale expression and solubility testing is an essential component of structural genomic pipelines. The SSGCID Protein Production Group at the University of Washington (UW-PPG) has developed a high-throughput screening (HTS) protocol for the measurement of protein recovery from immobilized metal-affinity chromatography (IMAC) which predicts successful purification of hexahistidine-tagged proteins. The protocol is based on manual transfer of samples using multichannel pipettors and 96-well plates and does not depend on the use of robotic platforms. This protocol has been applied to evaluate the expression and solubility of more than 4000 proteins expressed in E. coli. The UW-PPG also screens large-scale preparations for recovery from IMAC prior to purification. Analysis of these results show that our low-cost non-automated approach is a reliable method for the HTS demands typical of large structural genomic projects. This paper provides a detailed description of these protocols and statistical analysis of the SSGCID screening results. The results demonstrate that screening for proteins that yield high recovery after IMAC, both after small-scale and large-scale expression, improves the selection of proteins that can be successfully purified and will yield a crystal structure

  13. Removal of PCR error products and unincorporated primers by metal-chelate affinity chromatography.

    Directory of Open Access Journals (Sweden)

    Indhu Kanakaraj

    Full Text Available Immobilized Metal Affinity Chromatography (IMAC has been used for decades to purify proteins on the basis of amino acid content, especially surface-exposed histidines and "histidine tags" genetically added to recombinant proteins. We and others have extended the use of IMAC to purification of nucleic acids via interactions with the nucleotide bases, especially purines, of single-stranded RNA and DNA. We also have demonstrated the purification of plasmid DNA from contaminating genomic DNA by IMAC capture of selectively-denatured genomic DNA. Here we describe an efficient method of purifying PCR products by specifically removing error products, excess primers, and unincorporated dNTPs from PCR product mixtures using flow-through metal-chelate affinity adsorption. By flowing a PCR product mixture through a Cu(2+-iminodiacetic acid (IDA agarose spin column, 94-99% of the dNTPs and nearly all the primers can be removed. Many of the error products commonly formed by Taq polymerase also are removed. Sequencing of the IMAC-processed PCR product gave base-calling accuracy comparable to that obtained with a commercial PCR product purification method. The results show that IMAC matrices (specifically Cu(2+-IDA agarose can be used for the purification of PCR products. Due to the generality of the base-specific mechanism of adsorption, IMAC matrices may also be used in the purification of oligonucleotides, cDNA, mRNA and micro RNAs.

  14. Phospholipid bilayer affinities and solvation characteristics by electrokinetic chromatography with a nanodisc pseudostationary phase.

    Science.gov (United States)

    Penny, William M; Steele, Harmen B; Ross, J B Alexander; Palmer, Christopher P

    2017-03-01

    Phospholipid bilayer nanodiscs composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and synthetic maleic acid-styrene copolymer belts have been introduced as a pseudostationary phase (PSP) in electrokinetic chromatography and demonstrated good performance. The nanodiscs provide a suitable migration range and high theoretical plate counts. Using this nanodisc pseudostationary phase, the affinity of the bilayer structure for probe solutes was determined and characterized. Good correlation is observed between retention factors and octanol water partition coefficients for particular categories of solutes, but the general correlation is weak primarily because the nanodiscs show stronger affinity than octanol for hydrogen bond donors. This suggests that a more appropriate application of this technology is to measure and characterize interactions between solutes and lipid bilayers directly. Linear solvation energy relationship analysis of the nanodisc-solute interactions in this study demonstrates that the nanodiscs provide a solvation environment with low cohesivity and weak hydrogen bond donating ability, and provide relatively strong hydrogen bond acceptor strength. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Purification of CD47-streptavidin fusion protein from bacterial lysate using biotin-agarose affinity chromatography.

    Science.gov (United States)

    Salehi, Nasrin; Peng, Ching-An

    2016-07-08

    CD47 is a widely expressed transmembrane glycoprotein that modulates the activity of a plethora of immune cells via its extracellular domain. Therefore, CD47 plays important roles in the regulation of immune responses and may serve as targets for the development of immunotherapeutic agents. To make sure CD47 functionality is intact under the process of protein conjugation, CD47-streptavidin fusion protein was expressed and purified because it can easily bind to biotin-tagged materials via the unique biotin-streptavidin affinity. In this study, gene sequences of CD47 extracellular domain (CD47ECD) and core streptavidin (coreSA) with a total 834 bp were inserted into pET20b plasmid to construct recombinant plasmid encoding CD47-SA fusion gene. After bacteria transformation, the CD47-SA fusion protein was expressed by isopropyl-β-d-thiogalactopyranoside (IPTG) induction. The collected bacteria lysate was loaded on biotinylated agarose to proceed the purification of CD47-SA fusion protein. Due to the unexpected high affinity between biotin and coreSA, standard washing and elution approaches (e.g., varying pH, using biotin, and applying guanidine hydrochloride) reported for biotin-streptavidin affinity chromatography were not able to separate the target fusion protein. Instead, using low concentration of the non-ionic detergent Triton X-100 followed with alkaline buffer could efficiently weaken the binding between biotin and coreSA, thereby eluting out CD47-SA fusion protein from the biotin agarose column. The purified CD47-SA fusion protein was further characterized by molecular biology methods and its antiphagocytic functionality was confirmed by the phagocytosis assay. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:949-958, 2016. © 2016 American Institute of Chemical Engineers.

  16. Metal Ion Controlled Polymorphism of a Peptide

    DEFF Research Database (Denmark)

    Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel

    2011-01-01

    ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu......In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal......, …) in the peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...

  17. Determine equilibrium dissociation constant of drug-membrane receptor affinity using the cell membrane chromatography relative standard method.

    Science.gov (United States)

    Ma, Weina; Yang, Liu; Lv, Yanni; Fu, Jia; Zhang, Yanmin; He, Langchong

    2017-06-23

    The equilibrium dissociation constant (K D ) of drug-membrane receptor affinity is the basic parameter that reflects the strength of interaction. The cell membrane chromatography (CMC) method is an effective technique to study the characteristics of drug-membrane receptor affinity. In this study, the K D value of CMC relative standard method for the determination of drug-membrane receptor affinity was established to analyze the relative K D values of drugs binding to the membrane receptors (Epidermal growth factor receptor and angiotensin II receptor). The K D values obtained by the CMC relative standard method had a strong correlation with those obtained by the frontal analysis method. Additionally, the K D values obtained by CMC relative standard method correlated with pharmacological activity of the drug being evaluated. The CMC relative standard method is a convenient and effective method to evaluate drug-membrane receptor affinity. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Recombinant Passenger Proteins Can Be Conveniently Purified by One-Step Affinity Chromatography.

    Science.gov (United States)

    Wang, Hua-zhen; Chu, Zhi-zhan; Chen, Chang-chao; Cao, Ao-cheng; Tong, Xin; Ouyang, Can-bin; Yuan, Qi-hang; Wang, Mi-nan; Wu, Zhong-kun; Wang, Hai-hong; Wang, Sheng-bin

    2015-01-01

    Fusion tag is one of the best available tools to date for enhancement of the solubility or improvement of the expression level of recombinant proteins in Escherichia coli. Typically, two consecutive affinity purification steps are often necessitated for the purification of passenger proteins. As a fusion tag, acyl carrier protein (ACP) could greatly increase the soluble expression level of Glucokinase (GlcK), α-Amylase (Amy) and GFP. When fusion protein ACP-G2-GlcK-Histag and ACP-G2-Amy-Histag, in which a protease TEV recognition site was inserted between the fusion tag and passenger protein, were coexpressed with protease TEV respectively in E. coli, the efficient intracellular processing of fusion proteins was achieved. The resulting passenger protein GlcK-Histag and Amy-Histag accumulated predominantly in a soluble form, and could be conveniently purified by one-step Ni-chelating chromatography. However, the fusion protein ACP-GFP-Histag was processed incompletely by the protease TEV coexpressed in vivo, and a large portion of the resulting target protein GFP-Histag aggregated in insoluble form, indicating that the intracellular processing may affect the solubility of cleaved passenger protein. In this context, the soluble fusion protein ACP-GFP-Histag, contained in the supernatant of E. coli cell lysate, was directly subjected to cleavage in vitro by mixing it with the clarified cell lysate of E. coli overexpressing protease TEV. Consequently, the resulting target protein GFP-Histag could accumulate predominantly in a soluble form, and be purified conveniently by one-step Ni-chelating chromatography. The approaches presented here greatly simplify the purification process of passenger proteins, and eliminate the use of large amounts of pure site-specific proteases.

  19. Accumulation of metal ions by pectinates

    Science.gov (United States)

    Deiana, S.; Deiana, L.; Palma, A.; Premoli, A.; Senette, C.

    2009-04-01

    The knowledge of the mechanisms which regulate the interactions of metal ions with partially methyl esterified linear polymers of α-1,4 linked D-galacturonic acid units (pectinates), well represented in the root inner and outer apoplasm, is of great relevance to understand the processes which control their accumulation at the soil-root interface as well as their mobilization by plant metabolites. Accumulation of a metal by pectinates can be affected by the presence of other metals so that competition or distribution could be expected depending on the similar or different affinity of the metal ions towards the binding sites, mainly represented by the carboxylate groups. In order to better understand the mechanism of accumulation in the apoplasm of several metal ions, the sorption of Cd(II), Zn(II), Cu(II), Pb(II) and Cr(III) by a Ca-polygalacturonate gel, used as model of the soil-root interface, with a degree of esterification of 18% (PGAE1) and 65% (PGAE2) was studied at pH 3.0, 4.0, 5.0 and 6.0 in the presence of CaCl2 2.5 mM.. The results show that sorption increases with increasing both the initial metal concentration and pH. A similar sorption trend was evidenced for Cu(II) and Pb(II) and for Zn(II) and Cd(II), indicating that the mechanism of sorption for these two ionic couples is quite different. As an example, at pH 6.0 and an initial metal concentration equal to 2.0 mM, the amount of Cu(II) and Pb(II) sorbed was about 1.98 mg-1 of PGAE1 while that of Cd(II) and Zn(II) was about 1.2 mg-1. Cr(III) showed a rather different sorption trend and a much higher amount (2.8 mg-1of PGAE1 at pH 6.0) was recorded. The higher affinity of Cr(III) for the polysaccharidic matrix is attributable to the formation of Cr(III) polynuclear species in solution, as shown by the distribution diagrams obtained through the MEDUSA software. On the basis of these findings, the following affinity towards the PGAE1 can be assessed: Cr(III) > Cu(II) ? Pb(II) > Zn (II) ? Cd

  20. Dynamic affinity chromatography in the separation of sulfated lignins binding to thrombin

    Science.gov (United States)

    Liang, Aiye; Thakkar, Jay N.; Hindle, Michael; Desai, Umesh R.

    2013-01-01

    Sulfated low molecular weight lignins (LMWLs), a mixture of chemo-enzymatically prepared oligomers, have been found to be potent antagonists of coagulation. However, structures that induce anticoagulation remain unidentified. The highly polar sulfate groups on these molecules and the thousands of different structures present in these mixtures make traditional chromatographic resolution of sulfated LMWLs difficult. We performed dynamic thrombin affinity chromatography monitored using chromogenic substrate hydrolysis assay to isolate sulfated LMWL fractions that differed significantly in their biophysical and biochemical properties. Three fractions, I35, I55 and Peak II, were isolated from the starting complex mixture. Independent plasma clotting assays suggested that I35 possessed good anticoagulation potential (APTT = 4.2 μM; PT = 6.8 μM), while I55 and Peak II were approximately 10- and 100-fold less potent. The ESI-MS spectrum of this oligomeric fraction showed multiple peaks at 684.8, 610.6, 557.4, 541.4, 536.5, and 519.4 m/z, which most probably arise from variably functionalized (β-O4—β-β-linked trimers and/or a β-O4—β-O4-linked dimers. The first direct observation of these structures in sulfated LMWLs will greatly assist in the discovery of more potent sulfated LMWL-based anticoagulants. PMID:23122400

  1. Biomonitoring of selenoprotein P in human serum by fast affinity chromatography coupled to ICP-MS.

    Science.gov (United States)

    Heitland, Peter; Köster, Helmut D

    2018-04-01

    Most of the Se in human serum is bound to selenoprotein P (SEPP1) in which Se is present in form of selenocysteine. The SEPP1 is a new possible biomarker for the Se status and for this reason we developed a fast, simple and reliable method for the quantitative determination of SEPP1 in serum by affinity chromatography coupled to ICP-MS. It is possible to separate SEPP1 from other selenoproteins in serum in only 5 min, which allows high sample throughput in clinical laboratories. Measured and certified concentrations of total Se and Se(SEPP1) are in good agreement for the reference material SRM 1950. The SEPP1 concentration was stable in serum samples of 3 persons for a minimum of 2 weeks. Further results of method validation were described including internal and external quality assurance. The analytical method was applied for a biomonitoring study of the SEPP1 and total Se concentration in human serum of 50 occupationally non-exposed persons living in northern Germany. Concentration ranges and mean concentrations for Se(SEPP1) are 31.1-59.7 and 46.2 μg/L, respectively. The corresponding values for total Se are 62-120 and 83.5 μg/L. The mean percentage of total Se in serum present as SEPP1 is 58%. Copyright © 2018 Elsevier GmbH. All rights reserved.

  2. Effects of metal ions on the catalytic degradation of dicofol by cellulase.

    Science.gov (United States)

    Zhai, Zihan; Yang, Ting; Zhang, Boya; Zhang, Jianbo

    2015-07-01

    A new technique whereby cellulase immobilized on aminated silica was applied to catalyze the degradation of dicofol, an organochlorine pesticide. In order to evaluate the performance of free and immobilized cellulase, experiments were carried out to measure the degradation efficiency. The Michaelis constant, Km, of the reaction catalyzed by immobilized cellulase was 9.16 mg/L, and the maximum reaction rate, Vmax, was 0.40 mg/L/min, while that of free cellulase was Km=8.18 mg/L, and Vmax=0.79 mg/L/min, respectively. The kinetic constants of catalytic degradation were calculated to estimate substrate affinity. Considering that metal ions may affect enzyme activity, the effects of different metal ions on the catalytic degradation efficiency were explored. The results showed that the substrate affinity decreased after immobilization. Monovalent metal ions had no effect on the reaction, while divalent metal ions had either positive or inhibitory effects, including activation by Mn2+, reversible competition with Cd2+, and irreversible inhibition by Pb2+. Ca2+ promoted the catalytic degradation of dicofol at low concentrations, but inhibited it at high concentrations. Compared with free cellulase, immobilized cellulase was affected less by metal ions. This work provided a basis for further studies on the co-occurrence of endocrine-disrupting chemicals and heavy metal ions in the environment. Copyright © 2015. Published by Elsevier B.V.

  3. Multiheteromacrocycles that Complex Metal Ions. Sixth Progress Report, 1 May 1979-30 April 1980

    Science.gov (United States)

    Cram, D. J.

    1980-01-15

    Objective is to design synthesize, and evaluate cyclic and polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions, their complexes, and their clusters. Host organic compounds consist of strategically placed solvating, coordinating, and ion-pairing sites tied together by covalent bonds through hydrocarbon units around cavities shaped to be occupied by guest metal ions or by metal ions plus their ligands. Specificity in complexation is sought by matching the following properties of host and guest: cavity and metal ion sizes; geometric arrangements of binding sites; number of binding sites; character of binding sites; and valences. During this period, hemispherands based on an aryloxy or cyclic urea unit, spherands based on aryloxyl units only, and their complexes with alkali metals and alkaline earths were investigated. An attempt to separate {sup 6}Li and {sup 7}Li by gel permeation chromatography of lithiospherium chloride failed. (DLC)

  4. Evaluation of complexing agents and column temperature in ion chromatographic separation of alkali metals, alkaline earth metals and transition metals ion

    International Nuclear Information System (INIS)

    Kelkar, Anoop; Pandey, Ashish; Name, Anil B.; Das, D.K.; Behere, P.G.; Mohd Afzal

    2015-01-01

    The aim of ion chromatography method development is the resolution of all metal ions of interests. Resolution can be improved by changing the selectivity. Selectivity in chromatography can be altered by changes in mobile phase (eg eluent type, eluent strength) or through changes in stationary phase. Temperature has been used in altering the selectivity of particularly in reversed phase liquid chromatography and ion exchange chromatography. Present paper describe the retention behaviour of alkali metals, alkaline earth metals and transition metal ions on a silica based carboxylate function group containing analyte column. Alkali metals, alkaline earth metals and transition metal ions were detected by ion conductivity and UV-VIS detectors respectively

  5. Spectrophotometric study of some metal ions using some Schiff's bases

    International Nuclear Information System (INIS)

    Elnager, Nawal Mohomed Ibrahim

    2000-05-01

    In this work two schiff bases namely N,N Bis(benzoyl acetone)-o-phenylene diamine (NNBBPD) and N,N Bis(benzoyl acetone)-isopropylene diamine (NNBBAID) were prepared by direct coupling of benzoyl acetone with o-phenylene and isopropylene diamine respectively. The two reagents were identified by IR spectra, thin layer chromatography (TLC) and determination of the percentage of nitrogen contents (N%). It is found that the two reagents form coloured chelates with Fe (II), Fe (III), Cu (II), U (VI), Ni (II) and Co (II). The two reagents were used for the determination of Fe (II), Fe (III) and U (VI). The formulate of these metal ion complexes were obtained using continuous variations, mole ratio and slope ratio methods. Effect of two micelles, namely sodium n-dodecyl sulphate (SDS) and hexadecyl pyridinum broinide monohydrate (HPB) on metal ion complexes were studied. It is found that both of them increase the solubility and the absorbances of the metal ion complexes with variable effects of the absorption maxima. Calibration curves for Fe (II), Fe (II) and U (VI) were obtained in optimum conditions of pH and micelles solutions. (Author)

  6. Expression of a prokaryotic P-type ATPase in E. coli Plasma Membranes and Purification by Ni2+-affinity chromatography

    Directory of Open Access Journals (Sweden)

    Geisler Markus

    1998-01-01

    Full Text Available In order to characterize the P-type ATPase from Synechocystis 6803 [Geisler (1993 et al. J. Mol. Biol. 234, 1284] and to facilitate its purification, we expressed an N-terminal 6xHis-tagged version of the ATPase in an ATPase deficient E. coli strain. The expressed ATPase was immunodetected as a dominant band of about 97 kDa localized to the E. coli plasma membranes representing about 20-25% of the membrane protein. The purification of the Synecho-cystis 6xHis-ATPase by single-step Ni-affinity chromatography under native and denaturating conditions is described. ATPase activity and the formation of phosphointermediates verify the full function of the enzyme: the ATPase is inhibited by vanadate (IC50= 119 &mgr;M and the formation of phosphorylated enzyme intermediates shown by acidic PAGE depends on calcium, indicating that the Synechocystis P-ATPase functions as a calcium pump.

  7. Separation of Binding Protein of Celangulin V from the Midgut of Mythimna separata Walker by Affinity Chromatography

    Directory of Open Access Journals (Sweden)

    Lina Lu

    2015-05-01

    Full Text Available Celangulin V, an insecticidal compound isolated from the root bark of Chinese bittersweet, can affect the digestive system of insects. However, the mechanism of how Celangulin V induces a series of symptoms is still unknown. In this study, affinity chromatography was conducted through coupling of Celangulin V-6-aminoacetic acid ester to the CNBr-activated Sepharose 4B. SDS-PAGE was used to analyze the collected fraction eluted by Celangulin V. Eight binding proteins (Zinc finger protein, Thioredoxin peroxidase (TPx, Glyceraldehyde 3-phosphate dehydrogenase (GAPDH, SUMO E3 ligase RanBP2, Transmembrane protein 1, Actin, APN and V-ATPase were obtained and identified by LC/Q-TOF-MS from the midgut of Mythimna separata larvae. The potential of these proteins to serve as target proteins involved in the insecticidal activity of Celangulin V is discussed.

  8. ANALYSIS OF DRUG-PROTEIN BINDING BY ULTRAFAST AFFINITY CHROMATOGRAPHY USING IMMOBILIZED HUMAN SERUM ALBUMIN

    Science.gov (United States)

    Mallik, Rangan; Yoo, Michelle J.; Briscoe, Chad J.; Hage, David S.

    2010-01-01

    Human serum albumin (HSA) was explored for use as a stationary phase and ligand in affinity microcolumns for the ultrafast extraction of free drug fractions and the use of this information for the analysis of drug-protein binding. Warfarin, imipramine, and ibuprofen were used as model analytes in this study. It was found that greater than 95% extraction of all these drugs could be achieved in as little as 250 ms on HSA microcolumns. The retained drug fraction was then eluted from the same column under isocratic conditions, giving elution in less than 40 s when working at 4.5 mL/min. The chromatographic behavior of this system gave a good fit with that predicted by computer simulations based on a reversible, saturable model for the binding of an injected drug with immobilized HSA. The free fractions measured by this method were found to be comparable to those determined by ultrafiltration, and equilibrium constants estimated by this approach gave good agreement with literature values. Advantages of this method include its speed and the relatively low cost of microcolumns that contain HSA. The ability of HSA to bind many types of drugs also creates the possibility of using the same affinity microcolumn to study and measure the free fractions for a variety of pharmaceutical agents. These properties make this technique appealing for use in drug binding studies and in the high-throughput screening of new drug candidates. PMID:20227701

  9. Affinity-based screening of combinatorial libraries using automated, serial-column chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Evans, D.M.; Williams, K.P.; McGuinness, B. [PerSeptive Biosystems, Framingham, MA (United States)] [and others

    1996-04-01

    The authors have developed an automated serial chromatographic technique for screening a library of compounds based upon their relative affinity for a target molecule. A {open_quotes}target{close_quotes} column containing the immobilized target molecule is set in tandem with a reversed-phase column. A combinatorial peptide library is injected onto the target column. The target-bound peptides are eluted from the first column and transferred automatically to the reversed-phase column. The target-specific peptide peaks from the reversed-phase column are identified and sequenced. Using a monoclonal antibody (3E-7) against {beta}-endorphin as a target, we selected a single peptide with sequence YGGFL from approximately 5800 peptides present in a combinatorial library. We demonstrated the applicability of the technology towards selection of peptides with predetermined affinity for bacterial lipopolysaccharide (LPS, endotoxin). We expect that this technology will have broad applications for high throughput screening of chemical libraries or natural product extracts. 21 refs., 4 figs.

  10. Facile synthesis of Fe3O4@PDA core-shell microspheres functionalized with various metal ions: A systematic comparison of commonly-used metal ions for IMAC enrichment.

    Science.gov (United States)

    Jiang, Jiebing; Sun, Xueni; Li, Yan; Deng, Chunhui; Duan, Gengli

    2018-02-01

    Metal ions differed greatly in affinity towards phosphopeptides, and thus it is essential to systematically compare the phosphopeptides enrichment ability of different metal ions usually used in the IMAC techniques. In this work, for the first time, eight metal ions, including Nb 5+ , Ti 4+ , Zr 4+ , Ga 3+ , Y 3+ , In 3+ , Ce 4+ , Fe 3+ , were immobilized on the polydopamine (PDA)-coated Fe 3 O 4 (denoted as Fe 3 O 4 @PDA-M n+ ), and systematically compared by the real biosamples, in addition to standard phosphopeptides. Fe 3 O 4 microspheres were synthesized via the solvothermal reaction, followed by self-polymerization of dopamine on the surface. Then through taking advantage of the hydroxyl and amino group of PDA, the eight metal ions were easily adhered to the surface of Fe 3 O 4 @PDA. After characterization, the resultant Fe 3 O 4 @PDA-M n+ microspheres were applied to phosphopeptides enrichment based on the binding affinity between metal ions and phosphopeptides. According to the results, different metal ions presented diverse phosphopeptides enrichment efficiency in terms of selectivity, sensitivity and the enrichment ability from real complex samples, and Fe 3 O 4 @PDA-Nb 5+ and Fe 3 O 4 @PDA-Ti 4+ showed obvious advantages of the phosphopeptides enrichment effect after the comparison. This systematic comparison may provide certain reference for the use and development of IMAC materials in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Affinity chromatography of tetanus toxin, tetanus toxoid, and botulinum A toxin on synaptosomes, and differentiation of their acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Habermann, E [Giessen Univ. (Germany, F.R.). Pharmakologisches Inst.

    1976-01-01

    /sup 125/I-labelled tetanus toxin and /sup 125/I-labelled botulinum A neurotoxin are known to be specifically bound to brain synaptosomes. In order to discriminate between active toxin and inactive admixtures present in the starting material or arising during iodination, synaptosome columns were prepared using bromacetylcellulose and/or kieselgur (Celite) as carriers. Both types of columns adsorb the toxins from low ionic strength medium and release them if the pH and ionic strength are raised. Botulinum toxin was eluted with lower ionic strength than tetanus toxin, and could be freed from nontoxic admixtures. Analysis by affinity chromatography disclosed partially toxoided tetanus toxin in both labelled and unlabelled toxin samples. High concentrations of formaldehyde (0.5%) destroyed both toxicity and affinity to the synaptosomes of tetanus toxin. Low concentrations of formaldehyde (0.05%) yielded a derivative of low toxicity which was still, however less firmly, bound to synaptosomes. Tetanus and botulinum toxin differ by their acceptors. Whereas unlabelled botulinum toxin is unable to compete with labelled tetanus toxin, unlabelled tetanus toxin slightly competes with botulinum toxin. Both labelled toxins display anomalous binding behaviour in that they cannot be displaced completely even with a large excess of unlabelled toxin.

  12. Affinity chromatography of tetanus toxin, tetanus toxoid, and botulinum A toxin on synaptosomes, and differentiation of their acceptors

    International Nuclear Information System (INIS)

    Habermann, E.

    1976-01-01

    125 I-labelled tetanus toxin and 125 I-labelled botulinum A neurotoxin are known to be specifically bound to brain synaptosomes. In order to discriminate between active toxin and inactive admixtures present in the starting material or arising during iodination, synaptosome columns were prepared using bromacetylcellulose and/or kieselgur (Celite) as carriers. Both types of columns adsorb the toxins from low ionic strength medium and release them if the pH and ionic strength are raised. Botulinum toxin was eluted with lower ionic strength than tetanus toxin, and could be freed from nontoxic admixtures. Analysis by affinity chromatography disclosed partially toxoided tetanus toxin in both labelled and unlabelled toxin samples. High concentrations of formaldehyde (0.5%) destroyed both toxicity and affinity to the synaptosomes of tetanus toxin. Low concentrations of formaldehyde (0.05%) yielded a derivative of low toxicity which was still, however less firmly, bound to synaptosomes. Tetanus and botulinum toxin differ by their acceptors. Whereas unlabelled botulinum toxin is unable to compete with labelled tetanus toxin, unlabelled tetanus toxin slightly competes with botulinum toxin. Both labelled toxins display anomalous binding behaviour in that they cannot be displaced completely even with a large excess of unlabelled toxin. (orig.) [de

  13. Bioavailability of Metal Ions and Evolutionary Adaptation

    Directory of Open Access Journals (Sweden)

    Rolando P. Hong Enriquez

    2012-10-01

    Full Text Available The evolution of life on earth has been a long process that began nearly 3,5 x 109 years ago. In their initial moments, evolution was mainly influenced by anaerobic environments; with the rise of O2 and the corresponding change in bioavailability of metal ions, new mechanisms of survival were created. Here we review the relationships between ancient atmospheric conditions, metal ion bioavailability and adaptation of metals homeostasis during early evolution. A general picture linking geochemistry, biochemistry and homeostasis is supported by the reviewed literature and is further illustrated in this report using simple database searches.

  14. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  15. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Yuxiao; Zhang, Jianming; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2012-01-01

    Highlights: ► Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. ► MPCS was covalently modified by cysteine (MPCS–CO–Cys). ► MPCS–CO–Cys was first time used in electrochemical detection of heavy metal ions. ► Heavy metal ions such as Pb 2+ and Cd 2+ can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  16. Metallic ions in the upper atmosphere

    International Nuclear Information System (INIS)

    Kumar, S.

    1979-01-01

    During the past 20 years considerable progress has been made in establishing the presence of metallic ions in the sporadic E layers at mid latitudes and as discrete patches at high altitudes in the equatorial ionosphere. The E-region observations have been based on rocket flights, which represent local conditions faithfully. But the global distribution of metallic ions and variations relating to changes in season, local time, magnetic activity, etc., which require satellite data, have been largely unexamined. This work presents a few aspects of this missing global distribution over an altitude range of 100 to 1000 km, using the data from AE-C, AE-D, and OGO-6 satellites and the rocket flights 18.117 and 18.118 from Wallops Island on July 12 and 13, 1971. The rocket data provide a day-night pair of vertical profiles that include altitudes not covered by the satellites. Results are presented for Mg + , Al + , Si + and Fe + ions in terms of their detection probabilities, median concentrations and relative abundances with respect to Mg + ions as a function of significant geophysical parameters. Na + and K + ions have been excluded from this study because alkali metal ions driven off the spacecraft hamper the measurement of ambient Na + and K + ions. This study has indicated that in general different metallic ions appear together in comparable concentrations except for Al + , which is an order of magnitude smaller than the others

  17. Hepatitis C virus expressing flag-tagged envelope protein 2 has unaltered infectivity and density, is specifically neutralized by flag antibodies and can be purified by affinity chromatography

    DEFF Research Database (Denmark)

    Prentø, Jannick Cornelius; Bukh, Jens

    2011-01-01

    to the original virus. Flag-tagged virus was susceptible to flag-specific antibody neutralization, and infected cells could be immuno-stained by anti-flag antibodies. Using affinity chromatography with anti-flag resin we repeatedly obtained ~30% recovery of infectious particles. The full viability and unaltered...

  18. Mechanism of Metal Ion Activation of the Diphtheria Toxin Repressor DtxR

    Energy Technology Data Exchange (ETDEWEB)

    D' Aquino,J.; Tetenbaum-Novatt, J.; White, A.; Berkovitch, F.; Ringe, D.

    2005-01-01

    The diphtheria toxin repressor (DtxR) is a metal ion-activated transcriptional regulator that has been linked to the virulence of Corynebacterium diphtheriae. Structure determination has shown that there are two metal ion binding sites per repressor monomer, and site-directed mutagenesis has demonstrated that binding site 2 (primary) is essential for recognition of the target DNA repressor, leaving the role of binding site 1 (ancillary) unclear. Calorimetric techniques have demonstrated that although binding site 1 (ancillary) has high affinity for metal ion with a binding constant of 2 x 10{sup -7}, binding site 2 (primary) is a low-affinity binding site with a binding constant of 6.3 x 10{sup -4}. These two binding sites act in an independent fashion, and their contribution can be easily dissected by traditional mutational analysis. Our results clearly demonstrate that binding site 1 (ancillary) is the first one to be occupied during metal ion activation, playing a critical role in stabilization of the repressor. In addition, structural data obtained for the mutants Ni-DtxR(H79A, C102D), reported here, and the previously reported DtxR(H79A) have allowed us to propose a mechanism of metal activation for DtxR.

  19. Template-directed synthesis of oligoguanylic acids - Metal ion catalysis

    Science.gov (United States)

    Bridson, P. K.; Fakhrai, H.; Lohrmann, R.; Orgel, L. E.; Van Roode, M.

    1981-01-01

    The effects of Zn(2+), Pb(2+) and other metal ions on the efficiency and stereo-selectivity of the template-directed oligomerization of guanosine 5'-phosphorimidazolide are investigated. Reactions were run in the presence of a polyC template in a 2,6-lutidine buffer, and products analyzed by high-performance liquid chromatography on an RPC-5 column. The presence of the Pb(2+) ion is found to lead to the formation of 2'-5' linked oligomers up to the 40-mer, while Zn(2+) favors the formation of predominantly 3'-5' linked oligomers up to the 35-mer. When amounts of uracil, cytidine or adenosine 5'-phosphorimidazole equal to those of the guanosine derivative are included in the reaction mixture, the incorrect base is incorporated into the oligomer about 10% of the time with a Pb(2+) catalyst, but less than 0.5% of the time with Zn(2+). The Sn(2+), Sb(3+) and Bi(3+) ions are also found to promote the formation of 2'-5' oligomers, although not as effectively as Pb(2+), while no metal ions other than Zn(2+) promote the formation of the 3'-5' oligomers. The results may be important for the understanding of the evolution of nucleic acid replication in the absence of enzymes.

  20. Poisoning of liquid membrane carriers in extraction of metal ions

    International Nuclear Information System (INIS)

    Wang, Yuchun; Wang, Dexian

    1992-01-01

    As means of effective separation and preconcentration, emulsion liquid membranes (ELMs) have found application in many fields including biochemical separation, wastewater treatment, hydrometallurgy, and preconcentration in analytical chemistry. In the extraction of desired metal (scandium, mixed rare earths) ions using chelating extractants (TTA, HDEHP) as liquid membrane carriers, the carriers will become poisoned owing to the presence of even minute quantity of certain high ionic potential ions in the feed solution. The reason for the poisoning of carriers is that those ions have so much greater affinity than the desired ions for the membrane carrier that the ion-carrier coordination compound cannot be stripped at the interior interface of the membrane and gradually no more free carrier transports any metal ions across the membrane. The calculated results are in agreement with the experiments, and methods to avoid the poisoning are given in the paper

  1. Chromatography.

    Science.gov (United States)

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  2. Versatile high current metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1992-01-01

    A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. (orig)

  3. Novel metal ion surface modification technique

    International Nuclear Information System (INIS)

    Brown, I.G.; Godechot, X.; Yu, K.M.

    1990-10-01

    We describe a method for applying metal ions to the near-surface region of solid materials. The added species can be energetically implanted below the surface or built up as a surface film with an atomically mixed interface with the substrate; the metal ion species can be the same as the substrate species or different from it, and more than one kind of metal species can be applied, either simultaneously or sequentially. Surface structures can be fabricated, including coatings and thin films of single metals, tailored alloys, or metallic multilayers, and they can be implanted or added onto the surface and ion beam mixed. We report two simple demonstrations of the method: implantation of yttrium into a silicon substrate at a mean energy of 70 keV and a dose of 1 x 10 16 atoms/cm 2 , and the formation of a titanium-yttrium multilayer structure with ion beam mixing to the substrate. 17 refs., 3 figs

  4. Pseudo ribbon metal ion beam source

    International Nuclear Information System (INIS)

    Stepanov, Igor B.; Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-01-01

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface

  5. Pseudo ribbon metal ion beam source.

    Science.gov (United States)

    Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

    2014-02-01

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  6. Serodiagnosis of human neurocysticercosis using antigenic components of Taenia solium metacestodes derived from the unbound fraction from jacalin affinity chromatography

    Directory of Open Access Journals (Sweden)

    Gleyce Alves Machado

    2013-05-01

    Full Text Available The aim of the present study was to analyse Taenia solium metacestode antigens that were derived from the unbound fraction of jacalin affinity chromatography and subsequent tert-octylphenoxy poly (oxyethylene ethanol Triton X-114 (TX-114 partitioning in the diagnosis of human neurocysticercosis (NCC. Immunoassays were designed to detect T. solium-specific IgG antibodies by ELISA and immunoblot. Serum samples were collected from 132 individuals who were categorised as follows: 40 had NCC, 62 presented Taenia spp or other parasitic diseases and 30 were healthy individuals. The jacalin-unbound (J unbound fraction presented higher sensitivity and specificity rates than the jacalin-bound fraction and only this fraction was subjected to subsequent TX-114 partitioning, resulting in detergent (DJ unbound and aqueous (AJ unbound fractions. The ELISA sensitivity and specificity were 85% and 84.8% for J unbound , 92.5% and 93.5% for DJ unbound and 82.5% and 82.6% for AJ unbound . By immunoblot, the DJ unbound fraction showed 100% sensitivity and specificity and only serum samples from patients with NCC recognised the 50-70 kDa T. solium-specific components. We conclude that the DJ unbound fraction can serve as a useful tool for the differential immunodiagnosis of NCC by immunoblot.

  7. Metal ion implantation: Conventional versus immersion

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.

    1994-01-01

    Vacuum-arc-produced metal plasma can be used as the ion feedstock material in an ion source for doing conventional metal ion implantation, or as the immersing plasma for doing plasma immersion ion implantation. The basic plasma production method is the same in both cases; it is simple and efficient and can be used with a wide range of metals. Vacuum arc ion sources of different kinds have been developed by the authors and others and their suitability as a metal ion implantation tool has been well established. Metal plasma immersion surface processing is an emerging tool whose characteristics and applications are the subject of present research. There are a number of differences between the two techniques, both in the procedures used and in the modified surfaces created. For example, the condensibility of metal plasma results in thin film formation and subsequent energetic implantation is thus done through the deposited layer; in the usual scenario, this recoil implantation and the intermixing it produces is a feature of metal plasma immersion but not of conventional energetic ion implantation. Metal plasma immersion is more suited (but not limited) to higher doses (>10 17 cm -2 ) and lower energies (E i < tens of keV) than the usual ranges of conventional metal ion implantation. These and other differences provide these vacuum-arc-based surface modification tools with a versatility that enhances the overall technological attractiveness of both

  8. Engineering of microorganisms towards recovery of rare metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Kouichi; Ueda, Mitsuyoshi [Kyoto Univ. (Japan). Div. of Applied Life Sciences

    2010-06-15

    The bioadsorption of metal ions using microorganisms is an attractive technology for the recovery of rare metal ions as well as removal of toxic heavy metal ions from aqueous solution. In initial attempts, microorganisms with the ability to accumulate metal ions were isolated from nature and intracellular accumulation was enhanced by the overproduction of metal-binding proteins in the cytoplasm. As an alternative, the cell surface design of microorganisms by cell surface engineering is an emerging strategy for bioadsorption and recovery of metal ions. Cell surface engineering was firstly applied to the construction of a bioadsorbent to adsorb heavy metal ions for bioremediation. Cell surface adsorption of metal ions is rapid and reversible. Therefore, adsorbed metal ions can be easily recovered without cell breakage, and the bioadsorbent can be reused or regenerated. These advantages are suitable for the recovery of rare metal ions. Actually, the cell surface display of a molybdate-binding protein on yeast led to the enhanced adsorption of molybdate, one of the rare metal ions. An additional advantage is that the cell surface display system allows high-throughput screening of protein/peptide libraries owing to the direct evaluation of the displayed protein/peptide without purification and concentration. Therefore, the creation of novel metal-binding protein/ peptide and engineering of microorganisms towards the recovery of rare metal ions could be simultaneously achieved. (orig.)

  9. Poultry litter-based activated carbon for removing heavy metal ions in water.

    Science.gov (United States)

    Guo, Mingxin; Qiu, Guannan; Song, Weiping

    2010-02-01

    Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

  10. Combining metal oxide affinity chromatography (MOAC and selective mass spectrometry for robust identification of in vivo protein phosphorylation sites

    Directory of Open Access Journals (Sweden)

    Weckwerth Wolfram

    2005-11-01

    Full Text Available Abstract Background Protein phosphorylation is accepted as a major regulatory pathway in plants. More than 1000 protein kinases are predicted in the Arabidopsis proteome, however, only a few studies look systematically for in vivo protein phosphorylation sites. Owing to the low stoichiometry and low abundance of phosphorylated proteins, phosphorylation site identification using mass spectrometry imposes difficulties. Moreover, the often observed poor quality of mass spectra derived from phosphopeptides results frequently in uncertain database hits. Thus, several lines of evidence have to be combined for a precise phosphorylation site identification strategy. Results Here, a strategy is presented that combines enrichment of phosphoproteins using a technique termed metaloxide affinity chromatography (MOAC and selective ion trap mass spectrometry. The complete approach involves (i enrichment of proteins with low phosphorylation stoichiometry out of complex mixtures using MOAC, (ii gel separation and detection of phosphorylation using specific fluorescence staining (confirmation of enrichment, (iii identification of phosphoprotein candidates out of the SDS-PAGE using liquid chromatography coupled to mass spectrometry, and (iv identification of phosphorylation sites of these enriched proteins using automatic detection of H3PO4 neutral loss peaks and data-dependent MS3-fragmentation of the corresponding MS2-fragment. The utility of this approach is demonstrated by the identification of phosphorylation sites in Arabidopsis thaliana seed proteins. Regulatory importance of the identified sites is indicated by conservation of the detected sites in gene families such as ribosomal proteins and sterol dehydrogenases. To demonstrate further the wide applicability of MOAC, phosphoproteins were enriched from Chlamydomonas reinhardtii cell cultures. Conclusion A novel phosphoprotein enrichment procedure MOAC was applied to seed proteins of A. thaliana and to

  11. Immobilized Metal Affinity Chromatography Co-Purifies TGF-β1 with Histidine-Tagged Recombinant Extracellular Proteins

    Science.gov (United States)

    Kaur, Jasvir; Reinhardt, Dieter P.

    2012-01-01

    Extracellular recombinant proteins are commonly produced using HEK293 cells as histidine-tagged proteins facilitating purification by immobilized metal affinity chromatography (IMAC). Based on gel analyses, this one-step purification typically produces proteins of high purity. Here, we analyzed the presence of TGF-β1 in such IMAC purifications using recombinant extracellular fibrillin-1 fragments as examples. Analysis of various purified recombinant fibrillin-1 fragments by ELISA consistently revealed the presence of picomolar concentrations of active and latent TGF-β1, but not of BMP-2. These quantities of TGF-β1 were not detectable by Western blotting and mass spectrometry. However, the amounts of TGF-β1 were sufficient to consistently trigger Smad2 phosphorylation in fibroblasts. The purification mechanism was analyzed to determine whether the presence of TGF-β1 in these protein preparations represents a specific or non-specific co-purification of TGF-β1 with fibrillin-1 fragments. Control purifications using conditioned medium from non-transfected 293 cells yielded similar amounts of TGF-β1 after IMAC. IMAC of purified TGF-β1 and the latency associated peptide showed that these proteins bound to the immobilized nickel ions. These data clearly demonstrate that TGF-β1 was co-purified by specific interactions with nickel, and not by specific interactions with fibrillin-1 fragments. Among various chromatographic methods tested for their ability to eliminate TGF-β1 from fibrillin-1 preparations, gel filtration under high salt conditions was highly effective. As various recombinant extracellular proteins purified in this fashion are frequently used for experiments that can be influenced by the presence of TGF-β1, these findings have far-reaching implications for the required chromatographic schemes and quality controls. PMID:23119075

  12. Ultraviolet spectroscopy and metal ions detection

    International Nuclear Information System (INIS)

    Chaudry, M.A.

    1995-01-01

    The spectrochemical analysis is based on the interaction of radiation with the chemical species and depends on their nature, having pi, sigma or electrons, or d and f electrons, UV. Visible spectrophotometry has been used extensively in the detection and determination of both organics and inorganics. In UV detection the sensitivity is proportional to the bath length and the excitation coefficient of the given sample. It may be insensitive to many species unless these are converted to UV, absorbing derivatives. The technique has been applied for the monitoring of the effluents from HPLC, as chlorides or other complexes of various elements in this article the utility of HCl as reagent for the spectrophotometric determination of the metal ions like Al(III), As(III,IV), Ba(II), Cd(II), Ca(II) Ce(III), Cs(i), Cr(III,VI), Co(II), Cu(II), Dy(III), Eu(III), Gd(III), Au(III), Hf(IV), Ho(III), In(III), Fe(III), La(III), Pb(II), Lu (III), Mg(II), Mn(II), Hg(II), Mo(VI), Ni(II), Pd(II), Pt(IV), K(I), Pr(III), Re(VII), Ru(IV), Sm(III), Sc(III), Ag(I), Sr(II) Te(III), Th(IV), Sn(II,IV), Ti(III,IV), W(VI), U(VI), V(IV,V), Yb(III), Zn(II) AND Zr(IV) Ions i.e. for meta ions from d of the most of these metal ions has been found sufficient permit their detection in HPLC. Their molar absorptive have also been reported. Reference has also been provided to post column derivatization of some metal ions from d and f block elements for their detection in HPLC. (author) 12 figs.; 6 tabs.; 27 refs

  13. Metal ion binding to iron oxides

    Science.gov (United States)

    Ponthieu, M.; Juillot, F.; Hiemstra, T.; van Riemsdijk, W. H.; Benedetti, M. F.

    2006-06-01

    The biogeochemistry of trace elements (TE) is largely dependent upon their interaction with heterogeneous ligands including metal oxides and hydrous oxides of iron. The modeling of TE interactions with iron oxides has been pursued using a variety of chemical models. The objective of this work is to show that it is possible to model the adsorption of protons and TE on a crystallized oxide (i.e., goethite) and on an amorphous oxide (HFO) in an identical way. Here, we use the CD-MUSIC approach in combination with valuable and reliable surface spectroscopy information about the nature of surface complexes of the TE. The other objective of this work is to obtain generic parameters to describe the binding of the following elements (Cd, Co, Cu, Ni, Pb, and Zn) onto both iron oxides for the CD-MUSIC approach. The results show that a consistent description of proton and metal ion binding is possible for goethite and HFO with the same set of model parameters. In general a good prediction of almost all the collected experimental data sets corresponding to metal ion binding to HFO is obtained. Moreover, dominant surface species are in agreement with the recently published surface complexes derived from X-ray absorption spectroscopy (XAS) data. Until more detailed information on the structure of the two iron oxides is available, the present option seems a reasonable approximation and can be used to describe complex geochemical systems. To improve our understanding and modeling of multi-component systems we need more data obtained at much lower metal ion to iron oxide ratios in order to be able to account eventually for sites that are not always characterized in spectroscopic studies.

  14. Potentiometric titration of metal ions in ethanol.

    Science.gov (United States)

    Gibson, Graham T T; Mohamed, Mark F; Neverov, Alexei A; Brown, R S

    2006-09-18

    The potentiometric titrations of Zn2+, Cu2+ and 12 Ln3+ metal ions were obtained in ethanol to determine the titration constants (defined as the at which the [-OEt]/[Mx+]t ratios are 0.5, 1.5, and 2.5) and in two cases (La3+ and Zn2+) a complete speciation diagram. Several simple monobasic acids and aminium ions were also titrated to test the validity of experimental titration measurements and to establish new constants in this medium that will be useful for the preparation of buffers and standard solutions. The dependence of the titration constants on the concentration and type of metal ion and specific counterion effects is discussed. In selected cases, the titration profiles were analyzed using a commercially available fitting program to obtain information about the species present in solution, including La3+ for which a dimer model is proposed. The fitting provides the microscopic values for deprotonation of one to four metal-bound ethanol molecules. Kinetics for the La3+-catalyzed ethanolysis of paraoxon as a function of are presented and analyzed in terms of La3+ speciation as determined by the analysis of potentiometric titration curves. The stability constants for the formation of Zn2+ and Cu2+ complexes with 1,5,9-triazacyclododecane as determined by potentiometric titration are presented.

  15. Ionic Liquids as Extraction Media for Metal Ions

    Science.gov (United States)

    Hirayama, Naoki

    In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

  16. Extraction of alginate biopolymer present in marine alga sargassum filipendula and bioadsorption of metallic ions

    Directory of Open Access Journals (Sweden)

    Sirlei Jaiana Kleinübing

    2013-04-01

    Full Text Available This paper studies the bioadsorption of Pb2+, Cu2+, Cd2+ and Zn2+ ions by marine alga Sargassum filipendula and by the alginate biopolymer extracted from this alga. The objective is to evaluate the importance of this biopolymer in removing different metallic ions by the marine alga S. filipendula. In the equilibrium study, the same affinity order was observed for both bioadsorbents: Pb2+ > Cu2+ > Zn2+ > Cd2+. For Pb2+ and Cu2+ ions when the alginate is isolated and acting as bioadsorbents, adsorption capacities greater than those found for the alga were observed, indicating that it is the main component responsible for the removal of metallic ions. For Zn2+ and Cd2+ ions, greater bioadsorption capacities were observed for the alga, indicating that other functional groups of the alga, such as sulfates and amino, are also important in the bioadsorption of these ions.

  17. Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold.

    Science.gov (United States)

    Petoral, Rodrigo M; Björefors, Fredrik; Uvdal, Kajsa

    2006-11-23

    Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

  18. Isolation of a new ssDNA aptamer against staphylococcal enterotoxin B based on CNBr-activated sepharose-4B affinity chromatography.

    Science.gov (United States)

    Hedayati Ch, Mojtaba; Amani, Jafar; Sedighian, Hamid; Amin, Mohsen; Salimian, Jafar; Halabian, Raheleh; Imani Fooladi, Abbas Ali

    2016-09-01

    Staphylococcus aureus are potent human pathogens possessing arsenal of virulence factors. Staphylococcal food poisoning (SFP) and respiratory infections mediated by staphylococcal enterotoxin B (SEB) are common clinical manifestations. Many diagnostic techniques are based on serological detection and quantification of SEB in different food and clinical samples. Aptamers are known as new therapeutic and detection tools which are available in different ssDNA, dsDNA and protein structures. In this study, we used a new set of ssDNA aptamers against SEB. The methods used included preparation of a dsDNA library using standard SEB protein as the target analyte, affinity chromatography matrix in microfuge tubes, SELEX procedures to isolate specific ssDNA-aptamer as an affinity ligand, aptamer purification using ethanol precipitation method, affinity binding assay using ELISA, aptamer cloning and specificity test. Among 12 readable sequences, three of them were selected as the most appropriate aptamer because of their affinity and specificity to SEB. This study presents a new set of ssDNA aptamer with favorable selectivity to SEB through 12 rounds of SELEX. Selected aptamers were used to detect SEB in infected serum samples. Results showed that SEB c1 aptamer (2 µg SEB/100 nM aptamer) had favorable specificity to SEB (kd  = 2.3 × 10(-11) ). In conclusion, aptamers can be considered as useful tools for detecting and evaluating SEB. The results showed that affinity chromatography was an affordable assay with acceptable accuracy to isolate sensitive and selective novel aptamers. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Metal ion-assisted self-assembly of complexes for controlled and sustained release of minocycline for biomedical applications

    International Nuclear Information System (INIS)

    Zhang, Zhiling; Wang, Zhicheng; Nong, Jia; Nix, Camilla A; Zhong, Yinghui; Ji, Hai-Feng

    2015-01-01

    This study reports the development of novel drug delivery complexes self-assembled by divalent metal ion-assisted coacervation for controlled and sustained release of a hydrophilic small drug molecule minocycline hydrochloride (MH). MH is a multifaceted agent that has demonstrated therapeutic effects in infection, inflammation, tumor, as well as cardiovascular, renal, and neurological disorders due to its anti-microbial, anti-inflammatory, and cytoprotective properties. However, the inability to translate the high doses used in experimental animals to tolerable doses in human patients limits its clinical application. Localized delivery can potentially expose the diseased tissue to high concentrations of MH that systemic delivery cannot achieve, while minimizing the side effects from systemic exposure. The strong metal ion binding-assisted interaction enabled high drug entrapment and loading efficiency, and stable long term release for more than 71 d. Released MH demonstrated potent anti-biofilm, anti-inflammatory, and neuroprotective activities. Furthermore, MH release from the complexes is pH-sensitive as the chelation between minocycline and metal ions decreases with pH, allowing ‘smart’ drug release in response to the severity of pathology-induced tissue acidosis. This novel metal ion binding-mediated drug delivery mechanism can potentially be applied to other drugs that have high binding affinity for metal ions and may lead to the development of new delivery systems for a variety of drugs. (paper)

  20. Fluorescence signalling of the transition metal ions: Design strategy ...

    Indian Academy of Sciences (India)

    Unknown

    strategy based on the choice of the fluorophore component. N B SANKARAN, S ... skill for the development of fluorosensors of this kind. Further, the ... salts of the transition metal ions have been used for studying the influence of the metal ions.

  1. Metal ion sequestration: An exciting dimension for molecularly ...

    African Journals Online (AJOL)

    The use of a tight binding macrocyclic ligand to complex a metal ion so that this serves as receptee on the Molecularly Imprinted Polymer (MIP) receptor as described here affords a sequestration route for a targeted metal ion, with potential for environmental remediation and restoration applications. Ethylene glycol ...

  2. A biosystem for removal of metal ions from water

    Energy Technology Data Exchange (ETDEWEB)

    Kilbane, J.J. II.

    1990-01-01

    The presence of heavy metal ions in ground and surface waters constitutes a potential health risk and is an environmental concern. Moreover, processes for the recovery of valuable metal ions are of interest. Bioaccumulation or biosorption is not only a factor in assessing the environmental risk posed by metal ions; it can also be used as a means of decontamination. A biological system for the removal and recovery of metal ions from contaminated water is reported here. Exopolysaccharide-producing microorganisms, including a methanotrophic culture, are demonstrated to have superior metal binding ability, compared with other microbial cultures. This paper describes a biosorption process in which dried biomass obtained from exopolysaccharide-producing microorganisms is encapsulated in porous plastic beads and is used for metal ion binding and recovery. 22 refs., 13 figs.

  3. Nanostructured Block Polymer Membranes as High Capacity Adsorbers for the Capture of Metal Ions from Water

    Science.gov (United States)

    Boudouris, Bryan; Weidman, Jacob; Mulvenna, Ryan; Phillip, William

    The efficient removal of metal ions from aqueous streams is of significant import in applications ranging from industrial waste treatment to the purification of drinking water. An emerging paradigm associated with this separation is one that utilizes membrane adsorbers as a means by which to bind metal salt contaminants. Here, we demonstrate that the casting of an A-B-C triblock polymer using the self-assembly and non-solvent induced phase separation (SNIPS) methodology results in a nanoporous membrane geometry. The nature of the triblock polymer affords an extremely high density of binding sites within the membrane. As such, we demonstrate that the membranes with binding capacities equal to that of state-of-the-art packed bed columns. Moreover, because the affinity of the C moiety can be tuned, highly selective binding events can occur based solely on the chemistry of the block polymer and the metal ions in solution (i.e., in a manner that is independent of the size of the metal ions). Due to these combined facts, these membranes efficiently remove heavy metal (e.g., lead- and cadmium-based) salts from contaminated water streams with greater than 95% efficiency. Finally, we show that the membranes can be regenerated through a simple treatment in order to provide long-lasting adsorber systems as well. Thus, it is anticipated that these nanostructured triblock polymer membranes are a platform by which to obtain next-generation water purification processes.

  4. The sorption of metal ions on nanoscale zero-valent iron

    Directory of Open Access Journals (Sweden)

    Suponik Tomasz

    2017-01-01

    Full Text Available The injection of the colloidal suspensions of nano-iron (nZVI into an aquifer is a novel method of removing metal ions from acidic water. In the batch tests, the equilibrium study of the sorption of metal ions, Cu(II and Zn(II, on Green Tea nanoscale Zero-Valent Ion (GT-nZVI was carried out. The sorption of metal ions on this reactive material was described using the Langmuir, Freundlich and Sips models. This last model described in a better way the sorption equilibrium in the tested range of concentrations and temperature. The value of determination coefficient (R2 for the Sips model, for copper and zinc, was 0.9735 to 0.9995, respectively. GT-nZVI has very good properties in removing Cu(II and Zn(II from acidic water. The high values of qmaxS, the maximum adsorption capacity in the Sips model, amounting to 348.0 and 267.3 mg/g for Cu(II and Zn(II, indicate the high adsorption capacity of GT-nZVI. The analyzed metals have good or very good affinity with GT-nZVI.

  5. Metal ion-dependent DNAzymes and their applications as biosensors.

    Science.gov (United States)

    Lan, Tian; Lu, Yi

    2012-01-01

    Long considered to serve solely as the genetic information carrier, DNA has been shown in 1994 to be able to act as DNA catalysts capable of catalyzing a trans-esterification reaction similar to the action of ribozymes and protein enzymes. Although not yet found in nature, numerous DNAzymes have been isolated through in vitro selection for catalyzing many different types of reactions in the presence of different metal ions and thus become a new class of metalloenzymes. What remains unclear is how DNA can carry out catalysis with simpler building blocks and fewer functional groups than ribozymes and protein enzymes and how DNA can bind metal ions specifically to perform these functions. In the past two decades, many biochemical and biophysical studies have been carried out on DNAzymes, especially RNA-cleaving DNAzymes. Important insights have been gained regarding their metal-dependent activity, global folding, metal binding sites, and catalytic mechanisms for these DNAzymes. Because of their high metal ion selectivity, one of the most important practical applications for DNAzymes is metal ion detection, resulting in highly sensitive and selective fluorescent, colorimetric, and electrochemical sensors for a wide range of metal ions such as Pb(2+), UO2 2 +,[Formula: see text] including paramagnetic metal ions such as Cu(2+). This chapter summarizes recent progresses in in vitro selection of metal ion-selective DNAzymes, their biochemical and biophysical studies and sensing applications.

  6. Interaction of d(10) metal ions with thioether ligands: a thermodynamic and theoretical study.

    Science.gov (United States)

    Melchior, Andrea; Peralta, Elena; Valiente, Manuel; Tavagnacco, Claudio; Endrizzi, Francesco; Tolazzi, Marilena

    2013-05-07

    Thermodynamic parameters of complex formation between d(10) metal ions, such as Zn(2+), Cd(2+), Hg(2+) and Ag(+), and the macrocyclic thioether 1,4,7-trithiacyclononane ([9]AneS3) or the monodentate diethylsulfide (Et(2)S), in acetonitrile (AN) at 298.15 K, were studied by a systematic methodology including potentiometry, calorimetry and polarography. [9]AneS3 is able to form complexes with all the target cations, Et(2)S only reacts with Hg(2+) and Ag(+). Mononuclear ML(j) (j = 1, 2) complexes are formed with all the metal ions investigated, where the affinity order is Hg(2+) > Ag(+) > Cd(2+) ≈ Zn(2+) when L = [9]AneS3 and Hg(2+) > Ag(+) when L = Et(2)S. Enthalpy and entropy values are generally negative, as a consequence of both metal ion interactions with neutral ligands, the reagents' loss of degrees of freedom and the release of solvating molecules. DFT calculations on the complexes formed with [9]AneS3 in vacuum and in AN are also carried out, to correlate experimental and theoretical thermodynamic values and to highlight the interplay between the direct metal-thioether interaction and the solvation effects. Trends obtained for the stability constants and enthalpies of the 1 : 1 and 1 : 2 complexes in solvent well reproduce the experimental ones for all the divalent metal ion complexes with [9]AneS3 and indicate the release of 3 AN molecules in the formation of each consecutive octahedral complex. In addition, calculated and experimental values for Ag(+) complex formation in solution suggest that in AgL(2) species [9]AneS3 ligands are not both tridentate.

  7. Metal ion release from metallothioneins: proteolysis as an alternative to oxidation.

    Science.gov (United States)

    Peroza, Estevão A; dos Santos Cabral, Augusto; Wan, Xiaoqiong; Freisinger, Eva

    2013-09-01

    Metallothioneins (MTs) are among others involved in the cellular regulation of essential Zn(II) and Cu(I) ions. However, the high binding affinity of these proteins requires additional factors to promote metal ion release under physiological conditions. The mechanisms and efficiencies of these processes leave many open questions. We report here a comprehensive analysis of the Zn(II)-release properties of various MTs with special focus on members of the four main subfamilies of plant MTs. Zn(II) competition experiments with the metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) in the presence of the cellular redox pair glutathione (GSH)/glutathione disulfide (GSSG) show that plant MTs from the subfamilies MT1, MT2, and MT3 are remarkably more affected by oxidative stress than those from the Ec subfamily and the well-characterized human MT2 form. In addition, we evaluated proteolytic digestion with trypsin and proteinase K as an alternative mechanism for selective promotion of metal ion release from MTs. Also here the observed percentage of liberated metal ions depends strongly on the MT form evaluated. Closer evaluation of the data additionally allowed deducing the thermodynamic and kinetic properties of the Zn(II) release processes. The Cu(I)-form of chickpea MT2 was used to exemplify that both oxidation and proteolysis are also effective ways to increase the transfer of copper ions to other molecules. Zn(II) release experiments with the individual metal-binding domains of Ec-1 from wheat grain reveal distinct differences from the full-length protein. This triggers the question about the roles of the long cysteine-free peptide stretches typical for plant MTs.

  8. Non-Native Metal Ion Reveals the Role of Electrostatics in Synaptotagmin 1-Membrane Interactions.

    Science.gov (United States)

    Katti, Sachin; Nyenhuis, Sarah B; Her, Bin; Srivastava, Atul K; Taylor, Alexander B; Hart, P John; Cafiso, David S; Igumenova, Tatyana I

    2017-06-27

    C2 domains are independently folded modules that often target their host proteins to anionic membranes in a Ca 2+ -dependent manner. In these cases, membrane association is triggered by Ca 2+ binding to the negatively charged loop region of the C2 domain. Here, we used a non-native metal ion, Cd 2+ , in lieu of Ca 2+ to gain insight into the contributions made by long-range Coulombic interactions and direct metal ion-lipid bridging to membrane binding. Using X-ray crystallography, NMR, Förster resonance energy transfer, and vesicle cosedimentation assays, we demonstrate that, although Cd 2+ binds to the loop region of C2A/B domains of synaptotagmin 1 with high affinity, long-range Coulombic interactions are too weak to support membrane binding of individual domains. We attribute this behavior to two factors: the stoichiometry of Cd 2+ binding to the loop regions of the C2A and C2B domains and the impaired ability of Cd 2+ to directly coordinate the lipids. In contrast, electron paramagnetic resonance experiments revealed that Cd 2+ does support membrane binding of the C2 domains in full-length synaptotagmin 1, where the high local lipid concentrations that result from membrane tethering can partially compensate for lack of a full complement of divalent metal ions and specific lipid coordination in Cd 2+ -complexed C2A/B domains. Our data suggest that long-range Coulombic interactions alone can drive the initial association of C2A/B with anionic membranes and that Ca 2+ further augments membrane binding by the formation of metal ion-lipid coordination bonds and additional Ca 2+ ion binding to the C2 domain loop regions.

  9. Metal ion levels and lymphocyte counts

    DEFF Research Database (Denmark)

    Penny, Jeannette Ø; Varmarken, Jens-Erik; Ovesen, Ole

    2013-01-01

    BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) an....../ppb. INTERPRETATION: Circulating T-lymphocyte levels may decline after surgery, regardless of implant type. Metal ions-particularly cobalt-may have a general depressive effect on T- and B-lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762.......BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA....... RESULTS: The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect...

  10. Progress in metal ion separation and preconcentration : an overview.

    Energy Technology Data Exchange (ETDEWEB)

    Bond, A. H.

    1998-05-19

    A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented.

  11. Progress in metal ion separation and preconcentration: an overview

    International Nuclear Information System (INIS)

    Bond, A. H.

    1998-01-01

    A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented

  12. Affinity chromatography with pseudobiospecific ligands on high-performance supports for purification of proteins of biotechnological interest

    Directory of Open Access Journals (Sweden)

    N.B. Iannucci

    2003-03-01

    Full Text Available High-performance affinity matrices were obtained by attaching pseudobiospecific ligands to hollow-fibre membranes. The neutral protease contained in FlavourzymeTM was purified to homogeneity with Yellow 4R-HE affinity hollow-fibre membranes. Immobilisation of Red HE-3B allowed purification of a milk-clotting enzyme obtained by solid-state culture of Mucor bacilliformis. Copper immobilisation through iminodiacetic acid allowed fractionation of Biocon Bioconcentrated PlusTM to separate the pectinesterase-containing fraction. The productivity of the developed processes - 1900, 94 and 750 U/ml.min, respectively - was 10- to 15-fold higher than that achieved with the same ligands immobilised on agarose-based soft gels, mainly due to the shortening of the purification processes.

  13. Sorption of Heavy Metal Ions from Mine Wastewater by Activated ...

    African Journals Online (AJOL)

    Michael

    2016-12-02

    Dec 2, 2016 ... assess their heavy metal ions adsorption potential. The results show that the .... De-ionised water obtained from the Mineral. Engineering Laboratory of ... Batch adsorption experiment for each of the derived activated carbons ...

  14. Synthesis and characterization of metal ion-imprinted polymers

    Indian Academy of Sciences (India)

    2018-03-29

    Mar 29, 2018 ... polymers (CPs) were synthesized through the same method without using metal ion. Characterization of the ... tizanidine obtained from MMIP-NPs showed that signifi- .... C=C vari- able alkene stretching band at 1636 cm. −1.

  15. Preparation of Dithizone Functionalized Polystyrene for Detecting Heavy Metal Ion

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeon Ho; Kim, Younghun [Kwangwoon University, Seoul (Korea, Republic of)

    2015-04-15

    Colorimetric sensors were usually used to detect specific metal ions using selective color change of solutions. While almost organic dye in colorimetric sensors detected single molecule, dithizone (DTZ) solution could be separately detected above 5 kinds of heavy metal ions by the change of clear color. Namely, DTZ could be used as multicolorimetric sensors. However, DTZ was generally used as aqueous type and paper/pellet-type DTZ was not reported yet. Therefore, in this work, polystyrene (PS) was prepared to composite with DTZ and then DTZ/PS pellet was obtained, which was used to selectively detect 10 kinds of heavy metal ions. When 10 ppm of Hg and Co ions was exposed in DTZ/PS pellets, clear color change was revealed. It is noted that DTZ/PS pellet could be used in detecting of heavy metal ion as dry type.

  16. Metal ion binding with dehydroannulenes – Plausible two ...

    Indian Academy of Sciences (India)

    WINTEC

    Theoretical investigations have been carried out at B3LYP/6-311++G** level of theory to study the binding ... Alkali metals; dehydroannulenes; binding energy; penetration barrier. 1. .... can be discriminated from larger metal ions by running.

  17. Extracting metal ions with diphosphonic acid, or derivative thereof

    Science.gov (United States)

    Horwitz, Earl P.; Gatrone, Ralph C.; Nash, Kenneth L.

    1994-01-01

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

  18. Extracting metal ions with diphosphonic acid, or derivative thereof

    Science.gov (United States)

    Horwitz, E.P.; Gatrone, R.C.; Nash, K.L.

    1994-07-26

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulfur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described. 1 fig.

  19. Synthesis, photophysical and metal ion signalling behaviour of mono

    Indian Academy of Sciences (India)

    Unknown

    component systems, ... tion and heavy metal ions, is of considerable interest for various ... cause of the macrocyclic effect, expect to show ... whose chloride salt, mercuric chloride, was used. ... filtered, concentrated, washed with water and ex-.

  20. Metal ion separations using reactive membranes

    International Nuclear Information System (INIS)

    Way, J.D.

    1993-01-01

    A membrane is a barrier between two phases. If one component of a mixture moves through the membrane faster than another mixture component, a separation can be accomplished. Membranes are used commercially for many applications including gas separations, water purification, particle filtration, and macromolecule separations (Abelson). There are two points to note concerning this definition. First, a membrane is defined based on its function, not the material used to make the membrane. Secondly, a membrane separation is a rate process. The separation is accomplished by a driving force, not by equilibrium between phases. Liquids that are immiscible with the feed and product streams can also be used as membrane materials. Different solutes will have different solubilities and diffusion coefficients in a liquid. The product of the diffusivity and the solubility is known as the permeability coefficient, which is proportional to the solute flux. Differences in permeability coefficient will produce a separation between solutes at constant driving force. Because the diffusion coefficients in liquids are typically orders of magnitude higher than in polymers, a larger flux can be obtained. Further enhancements can be accomplished by adding a nonvolatile complexation agent to the liquid membrane. One can then have either coupled or facilitated transport of metal ions through a liquid membrane. The author describes two implementations of this concept, one involving a liquid membrane supported on a microporous membrane, and the other an emulsion liquid membrane, where separation occurs to internal receiving phases. Applications and costing studies for this technology are reviewed, and a brief summary of some of the problems with liquid membranes is presented

  1. Yeast enolase: mechanism of activation by metal ions.

    Science.gov (United States)

    Brewer, J M

    1981-01-01

    Yeast enolase as prepared by current procedures is inherently chemically homogeneous, though deamidation and partial denaturation can produce electrophoretically distinct forms. A true isozyme of the enzyme exists but does not survive the purification procedure. The chemical sequence for both has been established. The enzyme behaves in solution like a compact, nearly spherical molecule of moderate hydration. Strong intramolecular forces maintain the structure of the individual subunits. The enzyme as isolated is dimeric. If dissociated in the presence of magnesium ions and substrate, then the subunits are active, but if the dissociation occurs in the absence of metal ions, they are inactive until they have reassociated and undergone a first order "annealing" process. Magnesium (II) enhances association. The interaction between the subunits is hydrophobic in character. The enzyme can bind up to 2 mol of most metal ions in "conformational" sites which then allows up to 2 mol of substrate or some substrate analogue to bind. This is not sufficient for catalysis, but conformational metal ions do more than just allow substrate binding. A change in the environment of the metal ions occurs on substrate or substrate analogue binding. There is an absolute correlation between the occurrence of a structural change undergone by the 3-amino analogue of phosphoenolpyruvate and whether the metal ions produce any level of enzymatic activity. For catalysis, two more moles of metal ions, called "catalytic", must bind. There is evidence that the enzymatic reaction involves a carbanion mechanism. It is likely that two more moles of metal ion can bind which inhibit the reaction. The requirement for 2 mol of metal ion per subunit which contribute in different ways to catalysis is exhibited by a number of other enzymes.

  2. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  3. Metal ion removal from aqueous solution using physic seed hull.

    Science.gov (United States)

    Mohammad, Masita; Maitra, Saikat; Ahmad, Naveed; Bustam, Azmi; Sen, T K; Dutta, Binay K

    2010-07-15

    The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd(2+) and Zn(2+) metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd(2+) and Zn(2+) increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages-a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms-Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn(2+) and Cd(2+) was found to be comparable with other available adsorbents. About 36-47% of the adsorbed metal could be leached out of the loaded PSH using 0.1M HCl as the eluting medium. 2010 Elsevier B.V. All rights reserved.

  4. Oxidation of cyclohexane catalyzed by metal-ion-exchanged zeolites.

    Science.gov (United States)

    Sökmen, Ilkay; Sevin, Fatma

    2003-08-01

    The ion-exchange rates and capacities of the zeolite NaY for the Cu(II), Co(II), and Pb(II) metal ions were investigated. Ion-exchange equilibria were achieved in approximately 72 h for all the metal ions. The maximum ion exchange of metal ions into the zeolite was found to be 120 mg Pb(II), 110 mg Cu(II), and 100 mg Co(II) per gram of zeolite NaY. It is observed that the exchange capacity of a zeolite varies with the exchanged metal ion and the amount of metal ions exchanged into zeolite decreases in the sequence Pb(II) > Cu(II) > Co(II). Application of the metal-ion-exchanged zeolites in oxidation of cyclohexane in liquid phase with visible light was examined and it is observed that the order of reactivity of the zeolites for the conversion of cyclohexane to cyclohexanone and cyclohexanol is CuY > CoY > PbY. It is found that conversion increases by increase of the empty active sites of a zeolite and the formation of cyclohexanol is favored initially, but the cyclohexanol is subsequently converted to cyclohexanone.

  5. Coprecipitation of alkali metal ions with calcium carbonate

    International Nuclear Information System (INIS)

    Okumura, Minoru; Kitano, Yasushi

    1986-01-01

    The coprecipitation of alkali metal ions Li + , Na + , K + and Rb + with calcium carbonate has been studied experimentally and the following results have been obtained: (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite and their ionic radii shows a parabolic curve with a peak located at Na + which has approximately the same ionic radius as Ca 2+ . (3) However, the amounts of alkali metal ions coprecipitated with calcite decrease with increasing ionic radius of alkali metals. (4) Our results support the hypothesis that (a) alkali metals are in interstitial positions in the crystal structure of calcite and do not substitute for Ca 2+ in the lattice, but (b) in aragonite, alkali metals substitute for Ca 2+ in the crystal structure. (5) Magnesium ions in the parent solution increase the amounts of alkali metal ions (Li + , Na + , K + and Rb + ) coprecipitated with calcite but decrease those with aragonite. (6) Sodium-bearing aragonite decreases the incorporation of other alkali metal ions (Li + , K + and Rb + ) into the aragonite. (author)

  6. Protein selectivity with immobilized metal ion-tacn sorbents: chromatographic studies with human serum proteins and several other globular proteins.

    Science.gov (United States)

    Jiang, W; Graham, B; Spiccia, L; Hearn, M T

    1998-01-01

    The chromatographic selectivity of the immobilized chelate system, 1,4,7-triazocyclononane (tacn), complexed with the borderline metal ions Cu2+, Cr3+, Mn2+, Co2+, Zn2+, and Ni2+ has been investigated with hen egg white lysozyme, horse heart cytochrome c, and horse skeletal muscle myoglobin, as well as proteins present in partially fractionated preparations of human plasma. The effects of ionic strength and pH of the loading and elution buffers on protein selectivities of these new immobilized metal ion affinity chromatographic (IMAC) systems have been examined. The results confirm that immobilized Mn;pl-tacn sorbents exhibit a novel type of IMAC behavior with proteins. In particular, the chromatographic properties of these immobilized M(n+)-tacn ligand systems were significantly different compared to the IMAC behavior observed with other types of immobilized tri- and tetradentate chelating ligands, such as iminodiacetic acid, O-phosphoserine, or nitrilotriacetic acid, when complexed with borderline metal ions. The experimental results have consequently been evaluated in terms of the additional contributions to the interactive processes mediated by effects other than solely the conventional lone pair Lewis soft acid-Lewis soft base coordination interactions, typically found for the IMAC of proteins with borderline and soft metal ions, such as Cu2+ or Ni2+.

  7. Investigation of the potential of silica-bonded macrocyclic ligands for separation of metal ions from nuclear waste

    International Nuclear Information System (INIS)

    Camaioni, D.M.; Colton, N.G.; Bruening, R.L.

    1992-01-01

    This report describes the testing of some novel separations materials known as SuperLig trademark materials for their ability to separate efficiently and selectively certain metal ions from a synthetic, nonradioactive nuclear waste solution. The materials, developed and patented by IBC Advanced Technologies, are highly selective macrocyclic ligands that have been covalently bonded to silica gel. The SuperLig trademark materials that were tested are: (1) SuperLig trademark 601 for barium (Ba 2+ ) and strontium (Sr 2+ ) separation, (2) SuperLig trademark 602 for cesium (Cs + ) and rubidium (Rb + ) separation, (3) SuperLig trademark 27 for palladium (Pd 2+ ) separation, and (4) SuperLig trademark II for silver (Ag + ) and ruthenium (Ru 3+ ) separation. Our observations show that the technology for separating metal ions using silica-bonded macrocycles is essentially sound and workable to varying degrees of success that mainly depend on the affinity of the macrocycle for the metal ion of interest. It is expected that ligands will be discovered or synthesized that are amenable to separating metal ions of interest using this technology. Certainly more development, testing, and evaluation is warranted. 3 figs., 11 tabs

  8. Selective removal of heavy metal ions by disulfide linked polymer networks

    DEFF Research Database (Denmark)

    Ko, Dongah; Sung Lee, Joo; Patel, Hasmukh A.

    2017-01-01

    Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has...... a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal...... sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions―copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water....

  9. Purification of HBsAg produced by the human hepatoma cell line PLC/PRE/5 by affinity chromatography using monoclonal antibodies and application for ELISA diagnostic.

    Science.gov (United States)

    Merten, O W; Reiter, S; Scheirer, W; Katinger, H

    1983-01-01

    The human cell line PLC/PRF/5 (5) was used for the production of hepatitis B surface antigen subtype ad (HBsAg ad) and purified by affinity chromatography (AC) with monoclonal antibodies (mAb). mAb to HBsAg from mouse ascites have been purified by Protein A - AC prior coupling to AH-Sepharose 4B (Pharmacia). The combined procedure of ammonium-sulphate-precipitation of HBsAg from culture supernatants and immunosorbent-AC leads to approx. 700-fold purification. ELISA results using the mAb and the HBsAg for diagnostics of human serum, positive for anti-HBsAg-antibodies correlate with the RIA (AUSAB, Abbott).

  10. N-terminal processing of affinity-tagged recombinant proteins purified by IMAC procedures.

    Science.gov (United States)

    Mooney, Jane T; Fredericks, Dale P; Christensen, Thorkild; Bruun Schiødt, Christine; Hearn, Milton T W

    2015-07-01

    The ability of a new class of metal binding tags to facilitate the purification of recombinant proteins, exemplified by the tagged glutathione S-transferase and human growth hormone, from Escherichia coli fermentation broths and lysates has been further investigated. These histidine-containing tags exhibit high affinity for borderline metal ions chelated to the immobilised ligand, 1,4,7-triazacyclononane (tacn). The use of this tag-tacn immobilised metal ion affinity chromatography (IMAC) system engenders high selectivity with regard to host cell protein removal and permits facile tag removal from the E. coli-expressed recombinant protein. In particular, these tags were specifically designed to enable their efficient removal by the dipeptidyl aminopeptidase 1 (DAP-1), thus capturing the advantages of high substrate specificity and rates of cleavage. MALDI-TOF MS analysis of the cleaved products from the DAP-1 digestion of the recombinant N-terminally tagged proteins confirmed the complete removal of the tag within 4-12 h under mild experimental conditions. Overall, this study demonstrates that the use of tags specifically designed to target tacn-based IMAC resins offers a comprehensive and flexible approach for the purification of E. coli-expressed recombinant proteins, where complete removal of the tag is an essential prerequisite for subsequent application of the purified native proteins in studies aimed at delineating the molecular and cellular basis of specific biological processes. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Activities of lectins and their immobilized derivatives in detergent solutions. Implications on the use of lectin affinity chromatography for the purification of membrane glycoproteins.

    Science.gov (United States)

    Lotan, R; Beattie, G; Hubbell, W; Nicolson, G L

    1977-05-03

    The effects of several commonly used detergents on the saccharide-binding activities of lectins were investigated using lectin-mediated agglutination of formalin-fixed erythrocytes and affinity chromatography of glycoproteins on columns of lectins immobilized on polyacrylic hydrazide-Sepharose. In the hemagglutination assays, Ricinus communis I (RCA1) and II (RCAII), concanavalin A (Con A), and the agglutinins from peanut (PNA), soybean (SBA), wheat germ (WGA), and Limulus polyphemus (LPA) were tested with several concentrations of switterionic, cationic, anionic, and nonionic detergents. It was found that increasing detergent concentrations eventually affected hemagglutination titers in both test and control samples, and the highest detergent concentrations not affecting lectin hemagglutinating activities were determined. The effects of detergents on specific binding of [3H]fetuin and asialo[3H]fetuin to and elution from columns of immobilized lectins were less severe when compared with lectins in solution, suggesting that the lectins are stabilized by covalent attachment to agarose beads. Nonionic detergents did not affect the binding efficiency of the immobilized lectins tested at concentrations used for membrane solubilization while cationic and zwitterionic detergents caused significant inhibition of Con A- and SBA-Sepharose activities. In sodium deoxycholate (greater than 1%) only RCAI-Sepharose retained its activity, whereas the activities of the other lectins were reduced dramatically. Low concentrations of sodium dodecyl sulfate (0.05%) inhibited only the activity of immobilized SBA, but at higher concentration (0.1%) and prolonged periods of incubation (16 h, 23 degrees C) most of the lectins were inactivated. These data are compared with previous reports on the use of detergents in lectin affinity chromatography, and the conditions for the optimal use of detergents are detailed.

  12. Online micro-solid-phase extraction based on boronate affinity monolithic column coupled with high-performance liquid chromatography for the determination of monoamine neurotransmitters in human urine.

    Science.gov (United States)

    Yang, Xiaoting; Hu, Yufei; Li, Gongke

    2014-05-16

    Quantification of monoamine neurotransmitters is very important in diagnosing and monitoring of patients with neurological disorders. We developed an online analytical method to selectively determine urinary monoamine neurotransmitters, which coupled the boronate affinity monolithic column micro-solid-phase extraction with high-performance liquid chromatography (HPLC). The boronate affinity monolithic column was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and N,N'-methylenebisacrylamide (MBAA) in a stainless capillary column. The prepared monolithic column showed good permeability, high extraction selectivity and capacity. The column-to-column reproducibility was satisfactory and the enrichment factors were 17-243 for four monoamine neurotransmitters. Parameters that influence the online extraction efficiency, including pH of sample solution, flow rate of extraction and desorption, extraction volume and desorption volume were investigated. Under the optimized conditions, the developed method exhibited low limit of detection (0.06-0.80μg/L), good linearity (with R(2) between 0.9979 and 0.9993). The recoveries in urine samples were 81.0-105.5% for four monoamine neurotransmitters with intra- and inter-day RSDs of 2.1-8.2% and 3.7-10.6%, respectively. The online analytical method was sensitive, accurate, selective, reliable and applicable to analysis of trace monoamine neurotransmitters in human urine sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Adsorption of heavy metal ions on different clays

    International Nuclear Information System (INIS)

    Kruse, K.

    1992-01-01

    The aim of the present dissertation is to study the adsorption of heavy metal ions (Cd 2+ , Cu 2+ , Pb 2+ , Zn 2+ ) and their mixtures on clays. Different clays and bentonites (Ca 2+ -bentonite, activated Na + -bentonite, special heavy metal adsorber bentonite, two organophilic bentonites and a mixed layer clay) were used. The adsorbed metal ions were desorbed by appropriate solutions of HCl, EDTA and dioctadecyl dimethylammonium bromide. High concentrations of the heavy metal ions in the solutions can be reached. The desorption guarantees economical recycling. After desorption the clays were used (up to three times) for purification of contaminated water. The best experimental conditions, i.e. the highest adsorption of heavy metal ions from aqueous solutions was found for the greatest ratio of adsorbent/adsorbate. The adsorption was very fast. Calcium, sodium bentonites and the heavy metal adsorber bentonite attained the highest adsorption and desorption for Cu 2+, Zn 2+ and Pb 2+ ions. Cd 2+ ions were only absorbed by Silitonit, a special heavy metal absorber bentonite. The mixed layer clay (Opalit) ranges in adsorption and desorption properties below the unmodified Ca 2+ -bentonite (Montigel) or the activated Na + -bentonite. Only Tixosorb and Tixogel (organophilic bentonites) reach the lowest value of heavy metal adsorption. Only lead cations which are characterised by good polarizability were adsorbed at higher rates, therefore the organophilic bentonites are not appropriate for adsorption of heavy metal ions from aqueous solutions. Mixing of the metal ions generally decreases the adsorption of Pb 2+ and increases the adsorption of Cd 2+ . From mixtures if heavy metal ions adsorption and desorption of Cu 2+ ions reached a maximum for all clays. (author) figs., tabs., 56 refs

  14. Isolation of the Binding Protein of Periplocoside E from BBMVs in Midgut of the Oriental Amyworm Mythimna separata Walker (Lepidoptera: Noctuidae through Affinity Chromatography

    Directory of Open Access Journals (Sweden)

    Mingxing Feng

    2016-05-01

    Full Text Available Periplocosides, which are insecticidal compounds isolated from the root bark of Periploca sepium Bunge, can affect the digestive system of insects. However, the mechanism though which periplocosides induces a series of symptoms remains unknown. In this study, affinity chromatography was conducted by coupling periplocoside E-semi-succinic acid ester with epoxy amino hexyl (EAH sepharose 4B. Sodium dodecyl sulfonate-polyacrylamide gelelectrophoresis (SDS-PAGE was performed to analyze the fraction eluted by periplocoside E. Eight binding proteins (luciferin 4-monooxygenase, aminopeptidase N, aminopeptidase N3, nicotinamide adenine dinucleotide health (NADH dehydrogenase subunit 5, phosphatidylinositol 3-phosphate 3-phosphatase myotubularin, actin, uncharacterized family 31 glucosidase KIAA1161, and 2OG-Fe(2 oxygenase superfamily protein were obtained and identified through liquid chromatography/quadrupole-time of flight-mass spectrometry (LC/Q-TOF-MS analysis of the midgut epithelium cells of Mythimna separata larvae. Aminopeptidase N and N3 are potential putative targets of periplocosides. This study establishes the foundation for further research on the mechanism of action and target localization of periplocosides in agricultural pests.

  15. Purification of nitrate reductase from Nicotiana plumbaginifolia by affinity chromatography using 5'AMP-sepharose and monoclonal antibodies.

    Science.gov (United States)

    Moureaux, T; Leydecker, M T; Meyer, C

    1989-02-15

    Nitrate reductase was purified from leaves of Nicotiana plumbaginifolia using either 5'AMP-Sepharose chromatography or two steps of immunoaffinity chromatography involving monoclonal antibodies directed against nitrate reductase from maize and against ribulose-1,5-bisphosphate carboxylase from N. plumbaginifolia. Nitrate reductase obtained by the first method was purified 1000-fold to a specific activity of 9 units/mg protein. The second method produced an homogenous enzyme, purified 21,000-fold to a specific activity of 80 units/mg protein. SDS/PAGE of nitrate reductase always resulted in two bands of 107 and 99.5 kDa. The 107-kDa band was the nitrate reductase subunit of N. plumbaginifolia; the smaller one of 99.5 kDa is thought, as commonly reported, to result from proteolysis of the larger protein. The molecular mass of 107 kDa is close to the values calculated from the coding sequences of the two nitrate reductase genes recently cloned from tobacco (Nicotiana tabacum cv Xanthi).

  16. Metallic ion release from biocompatible cobalt-based alloy

    Directory of Open Access Journals (Sweden)

    Dimić Ivana D.

    2014-01-01

    Full Text Available Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5. After a certain immersion period (1, 3 and 6 weeks the concentrations of released ions were determined using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS. The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy. [Projekat Ministarstva nauke Republike Srbije, br. III 46010 i br. ON 174004

  17. Solution chemistry and separation of metal ions in leached solution

    International Nuclear Information System (INIS)

    Shibata, J.

    1991-01-01

    The method to presume a dissolved state of metal ions in an aqueous solution and the technology to separate and concentrate metal ions in a leached solution are described in this paper. It is very important for the separation of metal ions to know the dissolved state of metal ions. If we know the composition of an aqueous solution and the stability constants of metal-ligand complexes, we can calculate and estimate the concentration of each species in the solution. Then, we can decide the policy to separate and concentrate metal ions. There are several methods for separation and purification; hydroxide precipitation method, sulfide precipitation method, solvent extraction method and ion exchange resin method. Solvent extraction has been used in purification processes of copper refinery, uranium refinery, platinum metal refinery and rare earth metal refinery. Fundamental process of solvent extraction, a kind of commercial extractants, a way of determining a suitable extractant and an equipment are discussed. Finally, it will be emphasized how the separation of rare earths is improved in solvent extraction. (author) 21 figs., 8 tabs., 8 refs

  18. Use and optimization of a dual-flowrate loading strategy to maximize throughput in protein-a affinity chromatography.

    Science.gov (United States)

    Ghose, Sanchayita; Nagrath, Deepak; Hubbard, Brian; Brooks, Clayton; Cramer, Steven M

    2004-01-01

    The effect of an alternate strategy employing two different flowrates during loading was explored as a means of increasing system productivity in Protein-A chromatography. The effect of such a loading strategy was evaluated using a chromatographic model that was able to accurately predict experimental breakthrough curves for this Protein-A system. A gradient-based optimization routine is carried out to establish the optimal loading conditions (initial and final flowrates and switching time). The two-step loading strategy (using a higher flowrate during the initial stages followed by a lower flowrate) was evaluated for an Fc-fusion protein and was found to result in significant improvements in process throughput. In an extension of this optimization routine, dynamic loading capacity and productivity were simultaneously optimized using a weighted objective function, and this result was compared to that obtained with the single flowrate. Again, the dual-flowrate strategy was found to be superior.

  19. Heme-binding plasma membrane proteins of K562 erythroleukemia cells: Adsorption to heme-microbeads, isolation with affinity chromatography

    International Nuclear Information System (INIS)

    Majuri, R.

    1989-01-01

    Heme-microbeads attached themselves to the surface of viable K562 cells in a manner inhibitable by free hemin, indicating heme-recptor interaction. The microbeads were at first evenly distributed, but after prolonged incubation at 37 deg. C they formed a cap on one pole of the cells indicating clustering of the membrane heme receptors. Membrane proteins were labeled by culturing the cells in the presence of 35 S-methionine and were then solubilized with Triton X-114. The hydrophobic proteins contained about 20% of the total bound label. The solubilized membrane proteins were subsequently adsorbed to a heme-Sepharose affinity gel. According to SDS-electrophorsis and subsequent autoradiography, the immobilized heme captures two proteins or a protein with two polypeptides of 20 000 and 32 000 daltons. The larger of these was only wekly labeled with 35 S. The same two bands were observed if the cell surface proteins were labeled with 125 I by the lactoperoxidase method and the subsequently solubilized membrane proteins were isolated with heme-Sepharose. (author)

  20. Analysis of metal ion release from biomedical implants

    Directory of Open Access Journals (Sweden)

    Ivana Dimić

    2013-06-01

    Full Text Available Metallic biomaterials are commonly used for fixation or replacement of damaged bones in the human body due to their good combination of mechanical properties. The disadvantage of metals as implant materials is their susceptibility to corrosion and metal ion release, which can cause serious health problems. In certain concentrations metals and metal ions are toxic and their presence can cause diverse inflammatory reactions, genetic mutations or even cancer. In this paper, different approaches to metal ion release examination, from biometallic materials sample preparation to research results interpretation, will be presented. An overview of the analytical techniques, used for determination of the type and concentration of released ions from implants in simulated biofluids, is also given in the paper.

  1. Ionic liquids used in extraction and separation of metal ions

    International Nuclear Information System (INIS)

    Shen Xinghai; Xu Chao; Liu Xinqi; Chu Taiwei

    2006-01-01

    Ionic liquids as green solvents now have become a research hotspot in the field of separation of metal ions by solvent extraction. Experimental results of extraction of various metal ions with ionic liquids as solvents, including that of alkali metals, alkaline earths, transition metals rare earths and actinides are introduced. The extraction of uranium, plutonium and fission products that are involved in spent nuclear fuel reprocessing is also reviewed. The possible extraction mechanisms are discussed. Finally, the prospect of replacement of volatile and/or toxic organic solvents with environmentally benign ionic liquids for solvent extraction and the potency of applications of ionic liquids in solvent extraction are also commented. (authors)

  2. Designer ligands: The search for metal ion selectivity

    Directory of Open Access Journals (Sweden)

    Perry T. Kaye

    2011-03-01

    Full Text Available The paper reviews research conducted at Rhodes University towards the development of metal-selective ligands. The research has focused on the rational design, synthesis and evaluation of novel ligands for use in the formation of copper complexes as biomimetic models of the metalloenzyme, tyrosinase, and for the selective extraction of silver, nickel and platinum group metal ions in the presence of contaminating metal ions. Attention has also been given to the development of efficient, metal-selective molecular imprinted polymers.

  3. Hydrolysis of metal ions. Vol. 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Paul L. [Geochem Australia, Kiama, NSW (Australia); Ekberg, Christian [Chalmers Univ. of Technology, Goeteborg (Sweden). Nuclear Chemistry/Industrial Materials Recycling

    2016-07-01

    Filling the need for a comprehensive treatment that covers the theory, methods and the different types of metal ion complexes with water (hydrolysis), this handbook and ready reference is authored by a nuclear chemist from academia and an industrial geochemist. The book includes both cation and anion complexes, and approaches the topic of metal ion hydrolysis by first covering the background, before proceeding with an overview of the dissociation of water and then all different metal-water hydrolysis complexes and compounds. A must-have for scientists in academia and industry working on this interdisciplinary topic.

  4. Purification of camel liver catalase by zinc chelate affinity chromatography and pH gradient elution: An enzyme with interesting properties.

    Science.gov (United States)

    Chafik, Abdelbasset; Essamadi, Abdelkhalid; Çelik, Safinur Yildirim; Mavi, Ahmet

    2017-12-01

    Climate change and increasing temperatures are global concerns. Camel (Camelus dromedarius) lives most of its life under high environmental stress in the desert and represent ideal model for studying desert adaptation among mammals. Catalase plays a key role in protecting cells against oxidative stress. For the first time, catalase from camel liver was purified to homogeneity by zinc chelate affinity chromatography using pH gradient elution, a better separation was obtained. A purification fold of 201.81 with 1.17% yield and a high specific activity of 1132539.37U/mg were obtained. The native enzyme had a molecular weight of 268kDa and was composed of four subunits of equal size (65kDa). The enzyme showed optimal activity at a temperature of 45°C and pH 7.2. Thiol reagents, β-Mercaptoethanol and D,L-Dithiothreitol, inhibited the enzyme activity. The enzyme was inhibited by Al 3+ , Cd 2+ and Mg 2+ , whereas Ca 2+ , Co 2+ and Ni 2+ stimulated the catalase activity. Reduced glutathione has no effect on catalase activity. The K m and V max of the enzyme for hydrogen peroxide were 37.31mM and 6185157U/mg, respectively. Sodium azide inhibited the enzyme noncompetitively with K i value of 14.43μM, the IC 50 was found to be 16.71μM. The properties of camel catalase were different comparing to those of mammalian species. Relatively higher molecular weight, higher optimum temperature, protection of reduced glutathione from hydrogen peroxide oxidation and higher affinity for hydrogen peroxide and sodium azide, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Effects of metal-ion replacement on pyrazinamidase activity: A quantum mechanical study.

    Science.gov (United States)

    Khadem-Maaref, Mahmoud; Mehrnejad, Faramarz; Phirouznia, Arash

    2017-05-01

    Pyrazinamidase (PZase), a metalloenzyme, is responsible for acidic modification of pyrazinamide (PZA), a drug used in tuberculosis treatment. The metal coordination site of the enzyme is able to coordinate various divalent metal cofactors. Previous experimental studies have demonstrated that metal ions, such as Co 2+ , Mn 2+ , and Zn 2+ , are able to reactivate metal-depleted PZase, while others including Cu 2+ , Fe 2+ , and Mg 2+ , cannot restore activity. In this study, we investigated binding of various metal ions to the metal coordination site (MCS) of the enzyme using quantum mechanical calculations. We calculated the metal-ligand (residue) binding energy and the atomic partial charges in the presence of various ions. The results indicated that the tendency of alkaline earth metals to bind to PZase MCS is very low and not suitable for enzyme structural and catalytic function. In contrast, Co 2+ and Ni 2+ ions have very high binding affinity and are favorable to the structural and functional properties of the enzyme. Furthermore, we observed that the rate at which Ni 2+ , Co 2+ and Fe 2+ ions in PZase MCS polarize the OH bond of coordinated water molecules is much higher than the polarization rate created by other ions. This finding suggests that the coordination of Ni 2+ , Co 2+ , or Fe 2+ to PZase facilitates the deprotonation of coordinated water molecules to generate a nucleophile that catalyzes the enzymatic reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Metal ion-mediated agonism and agonist enhancement in melanocortin MC1 and MC4 receptors

    DEFF Research Database (Denmark)

    Holst, Birgitte; Elling, Christian E; Schwartz, Thue W

    2002-01-01

    -melanocortin stimulating hormone (alpha-MSH) in the MC1 and MC4 receptors, respectively. In the presence of peptide agonist, Zn(II) acted as an enhancer on both receptors, because it shifted the dose-response curves to the left: most pronounced was a 6-fold increase in alpha-MSH potency on the MC1 receptor. The effect......An endogenous metal-ion site in the melanocortin MC1 and MC4 receptors was characterized mainly in transiently transfected COS-7 cells. ZnCl(2) alone stimulated signaling through the Gs pathway with a potency of 11 and 13 microm and an efficacy of 50 and 20% of that of alpha...... affinities and profiles were similar for a number of the 2,2'-bipyridine and 1,10-phenanthroline analogs in complex with Zn(II) in the MC1 and MC4 receptors. However, the potencies and efficacies of the metal-ion complexes were very different in the two receptors, and close to full agonism was obtained...

  7. Simple method for Shiga toxin 2e purification by affinity chromatography via binding to the divinyl sulfone group.

    Directory of Open Access Journals (Sweden)

    Hideyuki Arimitsu

    Full Text Available Here we describe a simple affinity purification method for Shiga toxin 2e (Stx2e, a major causative factor of edema disease in swine. Escherichia coli strain MV1184 transformed with the expression plasmid pBSK-Stx2e produced Stx2e when cultivated in CAYE broth containing lincomycin. Stx2e bound to commercial D-galactose gel, containing α-D-galactose immobilized on agarose resin via a divinyl sulfone linker, and was eluted with phosphate-buffered saline containing 4.5 M MgCl2. A small amount of Stx2e bound to another commercial α-galactose-immobilized agarose resin, but not to β-galactose-immobilized resin. In addition, Stx2e bound to thiophilic adsorbent resin containing β-mercaptoethanol immobilized on agarose resin via a divinyl sulfone, and was purified in the same manner as from D-galactose gel, but the Stx2e sample contained some contamination. These results indicate that Stx2e bound to D-galactose gel mainly through the divinyl sulfone group on the resin and to a lesser extent through α-D-galactose. With these methods, the yields of Stx2e and attenuated mutant Stx2e (mStx2e from 1 L of culture were approximately 36 mg and 27.7 mg, respectively, and the binding capacity of the D-galactose gel and thiophilic adsorbent resin for Stx2e was at least 20 mg per 1 ml of resin. In addition, using chimeric toxins with prototype Stx2 which did not bind to thiophilic adsorbent resin and some types of mutant Stx2e and Stx2 which contained inserted mutations in the B subunits, we found that, at the least, asparagine (amino acid 17 of the B subunits was associated with Stx2e binding to the divinyl sulfone group. The mStx2e that was isolated exhibited vaccine effects in ICR mice, indicating that these methods are beneficial for large-scale preparation of Stx2e toxoid, which protects swine from edema disease.

  8. Coordination of cassava starch to metal ions and thermolysis of ...

    African Journals Online (AJOL)

    Cassava starch formed Werner-type complexes with ions of metals from the transition groups. This was proven by conductivity and electron paramagnetic resonance measurements. The coordination of starch to central metal ions influenced the thermal decomposition of starch. As a rule complexes started to decompose at ...

  9. Equilibrium and kinetics studies of metal ion adsorption on dyed ...

    African Journals Online (AJOL)

    GREGO

    2007-04-02

    Apr 2, 2007 ... Initial concentration of Cu(II) ions = 20 mg/l, adsorbent dose = 1.0 g. Table 2 Experiment Data of ... diffusivity of the metal ion would be independent of the extent of sorption .... exchange and adsorption. Equilibrium parameter.

  10. Heavy metal ion uptake properties of polystyrene-supported ...

    Indian Academy of Sciences (India)

    Unknown

    concentration on the uptake of metal ions have been studied. The uptake ... employed for the removal of heavy metal pollutants from industrial waste water. ... nitrate, mercuric chloride, cadmium nitrate and potassium dichromate salts. ... polymer resin was determined by reacting 50, 100, 150, 200, 250 and 300 ppm of metal.

  11. The kinetics and thermodynamics of adsorption of heavy metal ions ...

    African Journals Online (AJOL)

    Titanium-Pillared and Un-Pillared bentonite clays were studied in order to evaluate the thermodynamics and kinetics of heavy metal ion removal from aqueous solutions. The results showed that the maximum sorption of Cu, Cd, Hg and Pb ions occurred within 30 minutes. A pseudo-second order kinetic model was used to ...

  12. Equilibrium and kinetics studies of metal ion adsorption on dyed ...

    African Journals Online (AJOL)

    Batch equilibration studies were conducted to determine the nature of adsorption of Zn (II) and Cu (II) onto dyed coconut pollens. The nature of adsorption of metal ions was explained using the Langmuir equation. The calculated values of equilibrium parameter indicated favourable adsorption by the adsorbents. Also the ...

  13. Dimeric Complexes of Tryptophan with M2+ Metal Ions

    NARCIS (Netherlands)

    Dunbar, R. C.; Steill, J. D.; Polfer, N. C.; Oomens, J.

    2009-01-01

    IRMPD spectroscopy using the FELIX free electron laser and a Fourier transform ICR mass spectrometer was used to characterize the structures of electrosprayed dimer complexes M(2+)Trp(2) of tryptophan with a series of eight doubly charged metal ions, including alkaline earths Ca, Sr, and Ba, and

  14. Electrochemical reduction of metal ions in dilute solution using hydrogen

    NARCIS (Netherlands)

    Portegies Zwart, I.; Wijnbelt, E.C.W.; Janssen, L.J.J.

    1995-01-01

    Reduction of metal ions in dilute solutions is of great interest for purification of waste waters and process liquids. A new electrochemical cell has been introduced. This cell - a GBC-cell - is a combination of a gasdiffusion electrode in direct contact with a packed bed of carbon particles.

  15. Determination of Heavy Metal Ions in Tobacco and Tobacco Additives

    African Journals Online (AJOL)

    NJD

    This paper describes a new method for the simultaneous determination of heavy metal ions in tobacco and tobacco additives by ... The HPLC system consisted of a Waters 2690 Alliance separation ..... 1 Z.H. Shi and C.G. Fu, Talanta, 1997, 44, 593. ... 5 Q.F. Hu, G.Y. Yang, J.Y. Yin and Y. Yao, Talanta, 2002, 57, 751.

  16. Sorption of Molecular Oxygen by Metal-Ion Exchanger Nanocomposites

    Science.gov (United States)

    Krysanov, V. A.; Plotnikova, N. V.; Kravchenko, T. A.

    2018-03-01

    Kinetic features are studied of the chemisorption and reduction of molecular oxygen from water by metal-ion exchanger nanocomposites that differ in the nature of the dispersed metal and state of oxidation. In the Pd equilibrium sorption coefficient for oxygen dissolved in water ranges from 20 to 50, depending on the nature and oxidation state of the metal component.

  17. Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

    Science.gov (United States)

    Ma, Liyun; Li, Jing; Zhao, Juan; Liao, Han; Xu, Li; Shi, Zhi-guo

    2016-01-01

    In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

  18. Serial lectin affinity chromatography with concavalin A and wheat germ agglutinin demonstrates altered asparagine-linked sugar-chain structures of prostatic acid phosphatase in human prostate carcinoma.

    Science.gov (United States)

    Yoshida, K I; Honda, M; Arai, K; Hosoya, Y; Moriguchi, H; Sumi, S; Ueda, Y; Kitahara, S

    1997-08-01

    Differences between human prostate carcinoma (PCA, five cases) and benign prostatic hyperplasia (BPH, five cases) in asparagine-linked (Asn) sugar-chain structure of prostatic acid phosphatase (PAP) were investigated using lectin affinity chromatography with concanavalin A (Con A) and wheat germ agglutinin (WGA). PAP activities were significantly decreased in PCA-derived PAP, while no significant differences between the two PAP preparations were observed in the enzymatic properties (Michaelis-Menten value, optimal pH, thermal stability, and inhibition study). In these PAP preparations, all activities were found only in the fractions which bound strongly to the Con A column and were undetectable in the Con A unbound fractions and in the fractions which bound weakly to the Con A column. The relative amounts of PAP which bound strongly to the Con A column but passed through the WGA column, were significantly greater in BPH-derived PAP than in PCA-derived PAP. In contrast, the relative amounts of PAP which bound strongly to the Con A column and bound to the WGA column, were significantly greater in PCA-derived PAP than in BPH-derived PAP. The findings suggest that Asn-linked sugar-chain structures are altered during oncogenesis in human prostate and also suggest that studies of qualitative differences of sugar-chain structures of PAP might lead to a useful diagnostic tool for PCA.

  19. Cellulose Nanocrystals Obtained from Rice By-Products and Their Binding Potential to Metallic Ions

    Directory of Open Access Journals (Sweden)

    Vanessa L. Albernaz

    2015-01-01

    Full Text Available The present study aimed to develop and optimize a method to obtain cellulose nanocrystals from the agricultural by-products rice husk and straw and to evaluate their electrostructural modifications in the presence of metallic ions. First, different particle formation conditions and routes were tested and analyzed by spectrophotometry, dynamic light scattering (DLS, and Zeta potential measurements. Then, electrostructural effects of ions Na(I, Cd(II, and Al(III on the optimized nanoparticles were analyzed by atomic force microscopy (AFM, scanning electron microscopy (SEM, and electrical conductivity (EC assessments. The produced cellulose nanocrystals adopted a rod-like shape. AFM height distribution and EC data indicated that the nanocrystals have more affinity in binding with Na(I > Al(III > Cd(II. These data suggest that the use of these cellulose nanocrystals in the bioremediation field is promising, both in metal sorption from wastewater and as an alternative for water desalination.

  20. Obtaining sorbents of metal ions based on yeast cells Rhodotorula glutinis

    Directory of Open Access Journals (Sweden)

    Zh. Tattibayeva

    2013-05-01

    Full Text Available Ability to separate Cu2+ and Pb2+ ions from solution using yeast cells Rhodotorulа glutinis were considered. The degree of water purification in this case is of 60-70%. To increase the degree of binding of metal ions with cells and facilitate separation processes of water sorbents their immobilization on the surface of the water in the presence of polyethyleneimine was carried out. It is shown that under optimal conditions on the surface of 1 g diatomite 18 ∙ 106 cells is adsorbed. The high sorption capacity of diatomite justified its porosity. IR spectroscopic study of the interaction of the ions Cu2+ and Pb2+ with cell surface showed that high affinity Pb2 + ions to the surface of yeast cells is connected with form of slightly soluble compounds with the phosphate ions.

  1. Poly(2-FurylMethylenesulfide as a Resin to Uptake of Metal Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Damasceno J.

    2002-01-01

    Full Text Available The polymerization of poly (2- furyl methylenesulfide -- POLYTHIOFURFURAL -- was performed in an 0.36 mol/L aqueous solution of furfuraldehyde, saturated by bubbling hydrogen sulfide for 2 h at different temperatures. The reaction product was thoroughly washed and dried at 40 °C under vacuum. Poly (2-furyl methylenesulfyde is a yellow powder with a rather unpleasant odor. The polythiofurfural obtained [ -CH(C4H3O-S-] is a furan with thiols end groups. These are active adsorption centers for metal ions. The polythiofurfural was soluble in acetone and chloroform and its yields attained 80%. Morphological analysis by Scanning Eletronic Microscopy indicates a regular and dense surface in an interesting spacial arrangement. Preliminary isotherms adsorption studies indicate specific affinity forNi (II and Co (II and different capacity adsorption, 0.022 and 0.045 mmol per gram, respectively.

  2. Rechargeable dual-metal-ion batteries for advanced energy storage.

    Science.gov (United States)

    Yao, Hu-Rong; You, Ya; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

    2016-04-14

    Energy storage devices are more important today than any time before in human history due to the increasing demand for clean and sustainable energy. Rechargeable batteries are emerging as the most efficient energy storage technology for a wide range of portable devices, grids and electronic vehicles. Future generations of batteries are required to have high gravimetric and volumetric energy, high power density, low price, long cycle life, high safety and low self-discharge properties. However, it is quite challenging to achieve the above properties simultaneously in state-of-the-art single metal ion batteries (e.g. Li-ion batteries, Na-ion batteries and Mg-ion batteries). In this contribution, hybrid-ion batteries in which various metal ions simultaneously engage to store energy are shown to provide a new perspective towards advanced energy storage: by connecting the respective advantages of different metal ion batteries they have recently attracted widespread attention due to their novel performances. The properties of hybrid-ion batteries are not simply the superposition of the performances of single ion batteries. To enable a distinct description, we only focus on dual-metal-ion batteries in this article, for which the design and the benefits are briefly discussed. We enumerate some new results about dual-metal-ion batteries and demonstrate the mechanism for improving performance based on knowledge from the literature and experiments. Although the search for hybrid-ion batteries is still at an early age, we believe that this strategy would be an excellent choice for breaking the inherent disadvantages of single ion batteries in the near future.

  3. Selective removal of heavy metal ions by disulfide linked polymer networks

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Dongah [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark); Lee, Joo Sung [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Patel, Hasmukh A. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States); Jakobsen, Mogens H. [Department of Micro and Nano technology, Technical University of Denmark, Ørsteds Plads, 345B, 2800 Kgs. Lyngby (Denmark); Hwang, Yuhoon [Department of Environmental Engineering, Seoul National University of Science and Technology, 232 Gongreung-ro, Nowon-gu, Seoul 01811 (Korea, Republic of); Yavuz, Cafer T. [Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141 (Korea, Republic of); Hansen, Hans Chr. Bruun [Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Andersen, Henrik R., E-mail: henrik@ndersen.net [Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby (Denmark)

    2017-06-15

    Highlights: • Disulfide/thiol polymer networks are promising as sorbent for heavy metals. • Rapid sorption and high Langmuir affinity constant (a{sub L}) for stormwater treatment. • Selective sorption for copper, cadmium, and zinc in the presence of calcium. • Reusability likely due to structure stability of disulfide linked polymer networks. - Abstract: Heavy metal contaminated surface water is one of the oldest pollution problems, which is critical to ecosystems and human health. We devised disulfide linked polymer networks and employed as a sorbent for removing heavy metal ions from contaminated water. Although the polymer network material has a moderate surface area, it demonstrated cadmium removal efficiency equivalent to highly porous activated carbon while it showed 16 times faster sorption kinetics compared to activated carbon, owing to the high affinity of cadmium towards disulfide and thiol functionality in the polymer network. The metal sorption mechanism on polymer network was studied by sorption kinetics, effect of pH, and metal complexation. We observed that the metal ions–copper, cadmium, and zinc showed high binding affinity in polymer network, even in the presence of competing cations like calcium in water.

  4. Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

    International Nuclear Information System (INIS)

    Fish, D.

    1996-01-01

    The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished

  5. [PHEMA/PEI]–Cu(II) based immobilized metal affinity chromatography cryogels: Application on the separation of IgG from human plasma

    Energy Technology Data Exchange (ETDEWEB)

    Bakhshpour, Monireh; Derazshamshir, Ali; Bereli, Nilay [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey); Elkak, Assem [Laboratory of “Valorisation des Ressources Naturelles et Produits de Santé (VRNPS)”, Doctoral School of Sciences and Technology, Lebanese University, Rafic Hariri University Campus, Hadath (Lebanon); Denizli, Adil, E-mail: denizli@hacettepe.edu [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)

    2016-04-01

    The immobilized metal-affinity chromatography (IMAC) has gained significant interest as a widespread separation and purification tool for therapeutic proteins, nucleic acids and other biological molecules. The enormous potential of IMAC for proteins with natural surface exposed-histidine residues and for recombinant proteins with histidine clusters. Cryogels as monolithic materials have recently been proposed as promising chromatographic adsorbents for the separation of biomolecules in downstream processing. In the present study, IMAC cryogels have been synthesized and utilized for the adsorption and separation of immunoglobulin G (IgG) from IgG solution and whole human plasma. For this purpose, Cu(II)-ions were coupled to poly(hydroxyethyl methacrylate) PHEMA using poly(ethylene imine) (PEI) as the chelating ligand. In this study the cryogels formation optimized by the varied proportion of PEI from 1% to 15% along with different amounts of Cu (II) as chelating metal. The prepared cryogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The [PHEMA/PEI]–Cu(II) cryogels were assayed for their capability to bind the human IgG from aqueous solutions. The IMAC cryogels were found to have high affinity toward human IgG. The adsorption of human IgG was investigated onto the PHEMA/PEI cryogels with (10% PEI) and the concentration of Cu (II) varied as 10, 50, 100 and 150 mg/L. The separation of human IgG was achieved in one purification step at pH 7.4. The maximum adsorption capacity was observed at the [PHEMA/PEI]–Cu(II) (10% PEI) with 72.28 mg/g of human IgG. The purification efficiency and human IgG purity were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). - Highlights: • Cu(II)-ions were coupled to PHEMA using PEI as the chelating ligand. • Cu(II) chelated [PHEMA/PEI] cryogels for IgG separation were produced. • Maximum IgG adsorption capacity

  6. [PHEMA/PEI]–Cu(II) based immobilized metal affinity chromatography cryogels: Application on the separation of IgG from human plasma

    International Nuclear Information System (INIS)

    Bakhshpour, Monireh; Derazshamshir, Ali; Bereli, Nilay; Elkak, Assem; Denizli, Adil

    2016-01-01

    The immobilized metal-affinity chromatography (IMAC) has gained significant interest as a widespread separation and purification tool for therapeutic proteins, nucleic acids and other biological molecules. The enormous potential of IMAC for proteins with natural surface exposed-histidine residues and for recombinant proteins with histidine clusters. Cryogels as monolithic materials have recently been proposed as promising chromatographic adsorbents for the separation of biomolecules in downstream processing. In the present study, IMAC cryogels have been synthesized and utilized for the adsorption and separation of immunoglobulin G (IgG) from IgG solution and whole human plasma. For this purpose, Cu(II)-ions were coupled to poly(hydroxyethyl methacrylate) PHEMA using poly(ethylene imine) (PEI) as the chelating ligand. In this study the cryogels formation optimized by the varied proportion of PEI from 1% to 15% along with different amounts of Cu (II) as chelating metal. The prepared cryogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The [PHEMA/PEI]–Cu(II) cryogels were assayed for their capability to bind the human IgG from aqueous solutions. The IMAC cryogels were found to have high affinity toward human IgG. The adsorption of human IgG was investigated onto the PHEMA/PEI cryogels with (10% PEI) and the concentration of Cu (II) varied as 10, 50, 100 and 150 mg/L. The separation of human IgG was achieved in one purification step at pH 7.4. The maximum adsorption capacity was observed at the [PHEMA/PEI]–Cu(II) (10% PEI) with 72.28 mg/g of human IgG. The purification efficiency and human IgG purity were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). - Highlights: • Cu(II)-ions were coupled to PHEMA using PEI as the chelating ligand. • Cu(II) chelated [PHEMA/PEI] cryogels for IgG separation were produced. • Maximum IgG adsorption capacity

  7. Lipid vesicle-mediated affinity chromatography using magnetic activated cell sorting (LIMACS): a novel method to analyze protein-lipid interaction.

    Science.gov (United States)

    Bieberich, Erhard

    2011-04-26

    The analysis of lipid protein interaction is difficult because lipids are embedded in cell membranes and therefore, inaccessible to most purification procedures. As an alternative, lipids can be coated on flat surfaces as used for lipid ELISA and Plasmon resonance spectroscopy. However, surface coating lipids do not form microdomain structures, which may be important for the lipid binding properties. Further, these methods do not allow for the purification of larger amounts of proteins binding to their target lipids. To overcome these limitations of testing lipid protein interaction and to purify lipid binding proteins we developed a novel method termed lipid vesicle-mediated affinity chromatography using magnetic-activated cell sorting (LIMACS). In this method, lipid vesicles are prepared with the target lipid and phosphatidylserine as the anchor lipid for Annexin V MACS. Phosphatidylserine is a ubiquitous cell membrane phospholipid that shows high affinity to the protein Annexin V. Using magnetic beads conjugated to Annexin V the phosphatidylserine-containing lipid vesicles will bind to the magnetic beads. When the lipid vesicles are incubated with a cell lysate the protein binding to the target lipid will also be bound to the beads and can be co-purified using MACS. This method can also be used to test if recombinant proteins reconstitute a protein complex binding to the target lipid. We have used this method to show the interaction of atypical PKC (aPKC) with the sphingolipid ceramide and to co-purify prostate apoptosis response 4 (PAR-4), a protein binding to ceramide-associated aPKC. We have also used this method for the reconstitution of a ceramide-associated complex of recombinant aPKC with the cell polarity-related proteins Par6 and Cdc42. Since lipid vesicles can be prepared with a variety of sphingo- or phospholipids, LIMACS offers a versatile test for lipid-protein interaction in a lipid environment that resembles closely that of the cell membrane

  8. Metals in proteins: correlation between the metal-ion type, coordination number and the amino-acid residues involved in the coordination.

    Science.gov (United States)

    Dokmanić, Ivan; Sikić, Mile; Tomić, Sanja

    2008-03-01

    Metal ions are constituents of many metalloproteins, in which they have either catalytic (metalloenzymes) or structural functions. In this work, the characteristics of various metals were studied (Cu, Zn, Mg, Mn, Fe, Co, Ni, Cd and Ca in proteins with known crystal structure) as well as the specificity of their environments. The analysis was performed on two data sets: the set of protein structures in the Protein Data Bank (PDB) determined with resolution metal ion and its electron donors and the latter was used to assess the preferred coordination numbers and common combinations of amino-acid residues in the neighbourhood of each metal. Although the metal ions considered predominantly had a valence of two, their preferred coordination number and the type of amino-acid residues that participate in the coordination differed significantly from one metal ion to the next. This study concentrates on finding the specificities of a metal-ion environment, namely the distribution of coordination numbers and the amino-acid residue types that frequently take part in coordination. Furthermore, the correlation between the coordination number and the occurrence of certain amino-acid residues (quartets and triplets) in a metal-ion coordination sphere was analysed. The results obtained are of particular value for the identification and modelling of metal-binding sites in protein structures derived by homology modelling. Knowledge of the geometry and characteristics of the metal-binding sites in metalloproteins of known function can help to more closely determine the biological activity of proteins of unknown function and to aid in design of proteins with specific affinity for certain metals.

  9. Metal ion complex formation in small lakes of the Western Siberian Arctic zone

    Science.gov (United States)

    Kremleva, Tatiana; Dinu, Marina

    2017-04-01

    The paper is based on joint investigation of the Tyumen State University (Russia, Tyumen) and the Geochemistry and Analytical Chemistry Vernadsky Institute of Russian Academy of Sciences (Moscow, Russia) during 2012-2014 period. It presents the results of research of chemical composition of about 70 small lakes located in the area of tundra and northern taiga of West Siberia (Russia, Yamal-Nenets and Khanty-Mansi Autonomous Districts of the Tyumen region). The investigation includes determination of different parameters of natural water samples: • content of trace elements (Al, Fe, Mn, Cr, Cu, Ni, Zn, Cd, Co, Pb, etc., total more than 60 elements) by emission method with an inductively coupled plasma (ICP-MS) using mass spektrometrometre Element 2 equipment; • content of inorganic and total carbon (TIC and TC) by elemental analysis and the difference between the total and inorganic carbon gives the organic carbon content (TOC); • pH value by potentiometric method; • content of basic ions (Na+, Ca2+, K+, Mg2+, NH4+, Cl-, SO42-, NO3-, PO43-) by ion chromatography. Determination of the chemical composition of samples was conducted in the accredited laboratory according to standard procedures with regular quality control of results. Heavy metals in natural waters can exist in various forms: free (hydrated) ions bound in complexes with organic or inorganic ligands, as well as in the form of suspensions. The form of metal existence has a significant influence on their availability to transport in aquatic organisms. Metal ions associated in stable complexes with organic substances are considered less toxic. From the previous investigations state that the most stable complexes are ligands with organic ions Fe3+, Al3+. The main conclusion of the present research states that if the total content of aluminum, iron and manganese ions (meq/dm3) is equal to or greater than the concentration of dissolved organic carbon (TOC, mg/dm3) in lakes water other heavy metals will

  10. Protein A affinity chromatography of Chinese hamster ovary (CHO) cell culture broths containing biopharmaceutical monoclonal antibody (mAb): Experiments and mechanistic transport, binding and equilibrium modeling.

    Science.gov (United States)

    Grom, Matic; Kozorog, Mirijam; Caserman, Simon; Pohar, Andrej; Likozar, Blaž

    2018-04-15

    Protein A-based affinity chromatography is a highly-efficient separation method to capture, purify and isolate biosimilar monoclonal antibodies (mAb) - an important medical product of biopharmaceutical industrial manufacturing. It is considered the most expensive step in purification downstream operations; therefore, its performance optimization offers a great cost saving in the overall production expenditure. The biochemical mixture-separating specific interaction experiments with Chinese hamster ovary (CHO) cell culture harvest, containing glycosylated extracellular immunoglobulins (Ig), were made using five different state-of-the-art commercial resins. Packing breakthrough curves were recorded at an array of prolonged residence times. A mathematical simulation model was developed, applied and validated in combination with non-linear regression algorithms on bed effluent concentrations to determine the previously-unknown binding properties of stationary phase materials. Apart from the columns' differential partitioning, the whole external system was also integrated. It was confirmed that internal pore diffusion is the global rate-limiting resistance of the compound retention process. Immobilizing substrate characteristics, obtained in this engineering study, are indispensable for the scale-up of the periodic counter-current control with mechanistic load, elution and wash reduction. Furthermore, unit's volumetric flow screening measurements revealed dynamic effect correlation to eluate quality parameters, like the presence of aggregates, the host cell-related impurities at supernatant's extended feeding, and titre. Numerical sensitivity outputs demonstrated the impacts of fluidics (e.g. axial dispersion coefficient), thermodynamics (Langmuir adsorption) and mass transfer fluxes. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Identification of Litopenaeus vannamei BiP as a novel cellular attachment protein for white spot syndrome virus by using a biotinylation based affinity chromatography method.

    Science.gov (United States)

    Yuan, Zengzhi; Chen, Meng; Wang, Jingting; Li, Zhuoyu; Geng, Xuyun; Sun, Jinsheng

    2018-05-05

    White spot syndrome virus (WSSV) is a dangerous threat to shrimp farming that also attacks a wide range of crustaceans. Knowledge of the surface protein-protein interactions between the pathogen and host is very crucial to unraveling the molecular pathogenesis mechanisms of WSSV. In this study, LvBiP (Litopenaeus vannamei immunoglobulin heavy-chain-binding protein) was identified as a novel WSSV binding protein of L. vannamei by a biotinylation based affinity chromatography method. By using pull-down and ELISA assays, the binding of recombinant LvBiP to WSSV was proved to be specific and ATP- dependent. The interaction was also confirmed by the result of co-immunoprecipitation assay. Immunofluorescence studies revealed the co-localization of LvBiP with WSSV on the cell surface of shrimp haemocytes. Additionally, LvBiP is likely to play an important role in WSSV infection. Treatment of gill cellular membrane proteins (CMPs) with purified rLvBiP and antibody that specifically recognizes LvBiP, led to a significant reduction in the binding of WSSV to gill CMPs. In the in vivo neutralization assay, rLvBiP and anti-LvBiP polyclonal antibody partially blocked the infection of WSSV. Taken together, the results indicate that LvBiP, a molecular chaperon of the HSP70 family, is a novel host factor involved at the step of attachment of the WSSV to the host cells and a potential candidate of therapeutic target. Copyright © 2018. Published by Elsevier Ltd.

  12. Mutations induced by the action of metal ions in Pisum

    Energy Technology Data Exchange (ETDEWEB)

    von Rosen, G

    1957-01-01

    Simple metal ions may induce both radiomimetic effects and genuine gene mutations of the same type which occurs from ionizing radiation and from treatment with some chemical agencies as e.g., mustard gas. The main material during the experiments has been species of Pisum. The biochemical principle which lies behind these reactions is the complex-forming ability among those reactive bivalent metal elements. The author assumes that interruptions of the chelate formation in the cell synthesis form the real background to the observed activity of the metal ions. The possible role in the evolution of the plant- and animal kingdom and the probable value for plant-breeding of the mutation activity observed are suggested. A new field for mutation experiments may here be opened and the results must hitherto be judged as interesting and promising. 13 references, 7 figures, 4 tables.

  13. Accumulation of some metal ions on Bacillus licheniformis

    International Nuclear Information System (INIS)

    Hafez, M.B.; El-Desouky, W.; Fouad, A.

    2001-01-01

    Pure species of Bacillus licheniformis was used to remove ions from aqueous and simulated waste solutions. Metal ion accumulation on B. licheniformis was fast. Maximum uptake occurred at pH 4± 0.5 and at 25 ± 3 deg C. One gram of dry B. licheniformis was found to accumulate 115 mg cerium, 34 mg copper and 11 mg cobalt from aqueous solutions. The presence of certain foreign ions such as calcium, sodium and potassium decreased the uptake of ions by B. licheniformis, while citrate and EDTA prevent the uptake. Electron microscopic investigations showed that cerium (III), copper (II) and cobalt (II) accumulated extracellulary around the surface wall of B. licheniformis cells. A bio-adsorption mechanism between the metal ions and B. licheniformis cell wall was proposed. (author)

  14. Colored cool colorants based on rare earth metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Sreeram, Kalarical Janardhanan; Aby, Cheruvathoor Poulose; Nair, Balachandran Unni; Ramasami, Thirumalachari [Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020 (India)

    2008-11-15

    Colored pigments with high near infrared reflectance and not based on toxic metal ions like cadmium, lead and cobalt are being sought as cool colorants. Through appropriate doping two pigments Ce-Pr-Mo and Ce-Pr-Fe have been developed to offer a reddish brown and reddish orange color, respectively. These pigments have been characterized and found to be highly crystalline with an average size of 300 nm. A shift in band gap energy from 2.21 to 2.18 eV has been observed when Li{sub 2}CO{sub 3} was used as a mineralizer. Scanning electron microscope-energy dispersive X-ray analysis (SEM-EDAX) measurement indicate a uniform grind shape and distribution of metal ion, with over 65% reflectance in the NIR region, these pigments can well serve as cool colorants. (author)

  15. Investigation of metal ions sorption of brown peat moss powder

    Science.gov (United States)

    Kelus, Nadezhda; Blokhina, Elena; Novikov, Dmitry; Novikova, Yaroslavna; Chuchalin, Vladimir

    2017-11-01

    For regularities research of sorptive extraction of heavy metal ions by cellulose and its derivates from aquatic solution of electrolytes it is necessary to find possible mechanism of sorption process and to choice a model describing this process. The present article investigates the regularities of aliovalent metals sorption on brown peat moss powder. The results show that sorption isotherm of Al3+ ions is described by Freundlich isotherm and sorption isotherms of Na+ i Ni2+ are described by Langmuir isotherm. To identify the mechanisms of brown peat moss powder sorption the IR-spectra of the initial brown peat moss powder samples and brown peat moss powder samples after Ni (II) sorption were studied. Metal ion binding mechanisms by brown peat moss powder points to ion exchange, physical adsorption, and complex formation with hydroxyl and carboxyl groups.

  16. Protein isolation using affinity chromatography

    NARCIS (Netherlands)

    Besselink, T.

    2012-01-01

    Many product or even waste streams in the food industry contain components that may have potential for e.g. functional foods. These streams are typically large in volume and the components of interest are only present at low concentrations. A robust and highly selective separation process should

  17. Smart responsive microcapsules capable of recognizing heavy metal ions.

    Science.gov (United States)

    Pi, Shuo-Wei; Ju, Xiao-Jie; Wu, Han-Guang; Xie, Rui; Chu, Liang-Yin

    2010-09-15

    Smart responsive microcapsules capable of recognizing heavy metal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavy metal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavy metal ions. Copyright 2010 Elsevier Inc. All rights reserved.

  18. Electrical properties of polymer modified by metal ion implantation

    International Nuclear Information System (INIS)

    Wu Yuguang; Zhang Tonghe; Zhang Huixing; Zhang Xiaoji; Deng Zhiwei; Zhou Gu

    2000-01-01

    Polyethylene terephthalate (PET) has been modified by Ag, Cr, Cu and Si ion implantation with a dose range from 1x10 16 to 2x10 17 ions cm -2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been changed after metal ion implantation. The resistivity of implanted PET decreased obviously with an increase of ion dose. When metal ion dose of 2x10 17 cm -2 was selected, the resistivity of PET could be less than 10 Ω cm, but when Si ions are implanted, the resistivity of PET would be up to several hundred Ω cm. The results show that the conductive behavior of a metal ion implanted sample is obviously different from Si implantation one. The changes of the structure and composition have been observed with transmission electron microscope (TEM) and X-ray diffraction (XRD). The surface structure is varying after ion implantation and it is believed that the change would cause the improvement of the conductive properties. The mechanism of electrical conduction will be discussed

  19. Spectrophotometric determination of some metal ions using hydrazones

    International Nuclear Information System (INIS)

    Mohammed, M. S.

    2000-05-01

    In this research many starting materials were prepared, like methyl salicylate and salicylic acid hydrazide from which different derivatives of hydrazones were synthesized by coupling with carbonyl compounds like benzil monoxime and benzil mono hydrazone which are prepared and others like salicylaldehyde and benzoin. The hydrazones that were synthesized are salicylaldehyde salicylic acid hydrazone, benzoin salicylic acid hydrazone, benzil mono hydrazone salicylic acid hydrazone and benzil monoxime salicylic acid hydrazone. These reagents were determined by different methods, IR spectrophotometric determination, the nitrogen content method and melting point determination. These hydrazones act as ligands for determination of some metal ions by making different coloured complexes that were prepared for eight hydrazones with eight metal ions U (VI), Fe (II), Fe (III), Co (II), V (II), Mo (VI), Ni (II) and Cu (II). These complexes were determined by ultraviolet and visible spectrophotometer (UV/VIS) to detect their absorbance and wavelengths (λ max). The two hydrazones salicylaldehyde salicylic acid-hydrazone and benzoin salicylic acid hydrazone, were selected for determination of five metal ions (Fe (II), Fe (III), U (VI), Ni (II) and Cu (II)), using two micelles sodium n-dodecyl sulphate and pyridinium hexa decyl bromide mono hydrate. Their absorbance and wavelengths were detected using UV/VIS spectrophotometer. (Author)

  20. Do soft drinks affect metal ions release from orthodontic appliances?

    Science.gov (United States)

    Mikulewicz, Marcin; Wołowiec, Paulina; Loster, Bartłomiej W; Chojnacka, Katarzyna

    2015-01-01

    The effect of orange juice and Coca Cola(®) on the release of metal ions from fixed orthodontic appliances. A continuous flow system designed for in vitro testing of orthodontic appliances was used. Orange juice/Coca Cola(®) was flowing through the system alternately with artificial saliva for 5.5 and 18.5h, respectively. The collected samples underwent a multielemental ICP-OES analysis in order to determine the metal ions release pattern in time. The total mass of ions released from the appliance into orange juice and Coca Cola(®) (respectively) during the experiment was calculated (μg): Ni (15.33; 37.75), Cr (3.604; 1.052), Fe (48.42; ≥ 156.1), Cu (57.87, 32.91), Mn (9.164; 41.16), Mo (9.999; 30.12), and Cd (0.5967; 2.173). It was found that orange juice did not intensify the release of metal ions from orthodontic appliances, whereas Coca Cola(®) caused increased release of Ni ions. Copyright © 2015 Elsevier GmbH. All rights reserved.

  1. Complexation-induced supramolecular assembly drives metal-ion extraction.

    Science.gov (United States)

    Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

    2014-09-26

    Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Polymer Catalysts Imprinted with Metal Ions as Biomimics of Metalloenzymes

    Directory of Open Access Journals (Sweden)

    Joanna Czulak

    2013-01-01

    Full Text Available This work presents the preparation and properties of molecularly imprinted polymers (MIPs with catalytic centers that mimic the active sites of metalloenzymes. The MIP synthesis was based on suspension polymerization of functional monomers (4-vinylpyridine and acrylonitrile with trimethylolpropane trimethacrylate as a crosslinker in the presence of transition metal ions and 4-methoxybenzyl alcohol as a template. Four metal ions have been chosen for imprinting from among the microelements that are the most essential in the native enzymes: Cu2+, Co2+, Mn2+, and Zn2+. To prepare catalysts, the required loading of metal ions was obtained during sorption process. The catalysts imprinted with Cu2+, Co2+, and Zn2+ were successfully used for hydroquinone oxidation in the presence of hydrogen peroxide. The Mn2+-imprinted catalyst showed no activity due to the insufficient metal loading. Cu2+ MIP showed the highest efficiency. In case of Cu- and Co-MIP catalysts, their activity was additionally increased by the use of surface imprinting technique.

  3. A bis(3-hydroxy-4-pyridinone)-EDTA derivative as a strong chelator for M3+ hard metal ions: complexation ability and selectivity.

    Science.gov (United States)

    Gama, Sofia; Dron, Paul; Chaves, Silvia; Farkas, Etelka; Santos, M Amélia

    2009-08-21

    The study of chelating compounds is very important to solve problems related to human metal overload. 3-Hydroxy-3-pyridinones (HP), namely deferiprone, have been clinically used for chelating therapy of Fe and Al over the last decade. A multi-disciplinary search for alternative molecules led us to develop poly-(3-hydroxy-4-pyridinones) to increase metal chelation efficacy. We present herein a complexation study of a new bis-(3-hydroxy-4-pyridinone)-EDTA derivative with a set of M(3+) hard metal ions (M = Fe, Al, Ga), as well as Zn(2+), a biologically relevant metal ion. Thus a systematic aqueous solution equilibrium study was performed using potentiometric and spectroscopic techniques (UV-Vis, NMR methods). These set of results enables the establishment of specific models as well as the determination of thermodynamic stability constants and coordination modes of the metal complexes. The results indicate that this ligand has a higher affinity for chelating to these hard metal ions than deferiprone, and that the coordination occurs mostly through the HP moieties. Furthermore, it was also found that this ligand has a higher selectivity for chelating to M(3+) hard metal ions (M = Fe, Al, Ga) than Zn(2+).

  4. Mussel inspired preparation of amine-functionalized Kaolin for effective removal of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qiang; Liu, Meiying; Deng, Fengjie [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wang, Ke [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China); Huang, Hongye; Xu, Dazhuang; Zeng, Guangjian [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang, 330031 (China); Wei, Yen [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing, 100084 (China)

    2016-09-15

    Adsorption has been well regarded as a promising and efficient method for the removal of low concentration heavy metal ions in aqueous solutions. And kaolin has been considered as a kind of low cost and environment-friendly adsorbent for its abundant in nature. But the low adsorption capacity to heavy metal ions and severe aggregation in solution restrains its application. In this work, an environment-friendly adsorbent (denoted as Kaolin-PDA-PEI) was prepared based on mussel inspired chemistry and Michael addition reaction between high reaction activity of polydopamine (PDA) and polyethyleneimine (PEI), which was possesses a number of amine groups. The amine groups have displayed strong adsorption affinity towards copper ions. The successful modification of Kaolin by PDA and PEI was confirmed by a series of analyses, such as Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetry analysis and X-ray photoelectron spectroscopy. The effects of various parameters such as contact time, pH, initial concentrations of copper ions and temperature on copper ion adsorption by Kaolin-PDA-PEI were investigated. Kaolin-PDA-PEI shows higher adsorption capacity as compared with the raw Kaolin. The kinetic adsorption data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The Langmuir isotherm and Freundlich isotherm equilibrium model were applied to adsorption isotherm data to find the better fit isotherm. The results showed that adsorption process was well fitted by Langmuir isotherm model. The values of thermodynamics constants such as entropy change (ΔS{sup 0}), enthalpy change (ΔH{sup 0}) and Gibbs free energy (ΔG{sup 0}) were also calculated. The results indicated that the adsorption process of Kaolin-PDA-PEI were endothermic and spontaneous. - Graphical abstract: Amino groups functionalized Kaolin was facilely prepared via mussel inspired chemistry. The modified Kaolin exhibited much

  5. Mussel inspired preparation of amine-functionalized Kaolin for effective removal of heavy metal ions

    International Nuclear Information System (INIS)

    Huang, Qiang; Liu, Meiying; Deng, Fengjie; Wang, Ke; Huang, Hongye; Xu, Dazhuang; Zeng, Guangjian; Zhang, Xiaoyong; Wei, Yen

    2016-01-01

    Adsorption has been well regarded as a promising and efficient method for the removal of low concentration heavy metal ions in aqueous solutions. And kaolin has been considered as a kind of low cost and environment-friendly adsorbent for its abundant in nature. But the low adsorption capacity to heavy metal ions and severe aggregation in solution restrains its application. In this work, an environment-friendly adsorbent (denoted as Kaolin-PDA-PEI) was prepared based on mussel inspired chemistry and Michael addition reaction between high reaction activity of polydopamine (PDA) and polyethyleneimine (PEI), which was possesses a number of amine groups. The amine groups have displayed strong adsorption affinity towards copper ions. The successful modification of Kaolin by PDA and PEI was confirmed by a series of analyses, such as Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetry analysis and X-ray photoelectron spectroscopy. The effects of various parameters such as contact time, pH, initial concentrations of copper ions and temperature on copper ion adsorption by Kaolin-PDA-PEI were investigated. Kaolin-PDA-PEI shows higher adsorption capacity as compared with the raw Kaolin. The kinetic adsorption data were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The Langmuir isotherm and Freundlich isotherm equilibrium model were applied to adsorption isotherm data to find the better fit isotherm. The results showed that adsorption process was well fitted by Langmuir isotherm model. The values of thermodynamics constants such as entropy change (ΔS"0), enthalpy change (ΔH"0) and Gibbs free energy (ΔG"0) were also calculated. The results indicated that the adsorption process of Kaolin-PDA-PEI were endothermic and spontaneous. - Graphical abstract: Amino groups functionalized Kaolin was facilely prepared via mussel inspired chemistry. The modified Kaolin exhibited much enhanced adsorption

  6. Simultaneous high-throughput determination of interaction kinetics for drugs and cyclodextrins by high performance affinity chromatography with mass spectrometry detection.

    Science.gov (United States)

    Wang, Caifen; Wang, Xiaobo; Xu, Xiaonan; Liu, Botao; Xu, Xu; Sun, Lixin; Li, Haiyan; Zhang, Jiwen

    2016-02-25

    The individual determination of the apparent dissociation rate constant (kd,app) using high performance affinity chromatography (HPAC) is a tedious process requiring numerous separate tests and massive data fitting, unable to provide the apparent association rate constant (ka) and equilibrium binding constant (Ka). In this study, a HPAC with mass spectrometry detection (HPAC-MS/MS) was employed to determine the drug-cyclodextrin (CD) interaction kinetics with low sample loading quantity (drugs determined in one injection. The kd,app measured by HPAC-MS/MS approach were 0.89 ± 0.07, 4.34 ± 0.01, 1.48 ± 0.01 and 7.77 ± 0.04 s(-1) for ketoprofen, trimethoprim, indapamide and acetaminophen, with kd,app for acetaminophen consistent with that from the HPAC method with UV detector in our previous studies. For twenty drugs with diverse structures and chemical properties, good correlationship was found between kd,app measured by single compound analysis method and high-throughput HPAC-MS/MS approach, with the correlation coefficient of 0.987 and the significance F less than 0.001. Comprehensive quantification of ka,app, kd,app and Ka values was further performed based on the measurement of kd,app by peak profiling method and Ka by the peak fitting method. And the investigation of the drug-CD interaction kinetics under different conditions indicated that the column temperature and mobile phase composition significantly affected the determination of ka,app, kd,app and Ka while also dependent on the acidity and basicity of drugs. In summary, the high-throughput HPAC-MS/MS approach has been demonstrated high efficiency in determination of the drug-CD primary interaction kinetic parameter, especially, kd,app, being proven as a novel tool in screening the right CD for the solubilization of the right drug. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Local coordination of polyvalent metal ions in molten halide mixtures

    International Nuclear Information System (INIS)

    Akdeniz, Z.; Tosi, M.P.

    1989-07-01

    Ample experimental evidence is available in the literature on the geometry and the stability of local coordination for polyvalent metal ions in molten mixtures of their halides with alkali halides. Recent schemes for classifying this evidence are discussed. Dissociation of tetrahedral halocomplexes in good ionic systems can be viewed as a classical Mott problem of bound-state stability in a conducting matrix. More generally, structural coordinates can be constructed from properties of the component elements, to separate out systems with long-lived fourfold or sixfold coordination and to distinguish between these. (author). 11 refs, 1 fig

  8. Studies on the dryolysis reactions of metal ions

    International Nuclear Information System (INIS)

    Baes, C.F. Jr.

    1977-01-01

    Research is reported on metallic ions produced in solutions at low concentrations as mononuclear hydrolysis products. The method for studying the mononuclear species is to measure the solubility of the oxide or hydroxide solid phase that is stable under the conditions of interest. Column solubility measurements of Al(OH) 3 (Gibbsite) in NaCl solution as a function of pH, temperature, and ionic strength are being conducted in order to better establish the stability of the intermediate species Al(OH) 2 + and Al(OH) 3 (aq)

  9. Adsorption of heavy metals ions on portulaca oleracea plants

    International Nuclear Information System (INIS)

    Naqvi, R.R.

    2005-01-01

    The aim of this study is to report the ability of portulaca oleracea (Fershi in Urdu) biomass grown in uncontaminated soils to adsorb or uptake lead, cadmium, arsenic, cobalt and copper from aqueous solutions. In order to help understand the metal binding mechanism, laboratory experiments performance to determine optimal binding, and binding capacity for each of the above mentioned metals. These experiments were carried out for the mass of crushed portulaca stems. Portulaca is a plant that grows abundantly in temperature climate in the area of Quetta Balochistan. It has reddish stem and thick succulent leaves. This plant has been found to be good adsorbent for heavy metals ions. (author)

  10. High-current pulsed ion source for metallic ions

    International Nuclear Information System (INIS)

    Gavin, B.; Abbott, S.; MacGill, R.; Sorensen, R.; Staples, J.; Thatcher, R.

    1981-03-01

    A new sputter-ion PIG source and magnet system, optimized for intermediate charge states, q/A of 0.02 to 0.03, is described. This source will be used with the new Wideroe-based injector for the SuperHILAC. Pulsed electrical currents of several emA of heavy metal ions have been produced in a normalized emittance area of .05π cm-mr. The source system is comprised of two electrically separate anode chambers, one in operation and one spare, which can be selected by remote control. The entire source head is small and quickly removable

  11. Ion beam analysis of metal ion implanted surfaces

    International Nuclear Information System (INIS)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T.; Sood, D.K.

    1993-01-01

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs

  12. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P J; Chu, J W; Johnson, E P; Noorman, J T [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D K [Royal Melbourne Inst. of Tech., VIC (Australia)

    1994-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  13. Solution thermodynamics of rare-earth metal ions - physicochemical study-

    Energy Technology Data Exchange (ETDEWEB)

    Amerkhanova, Sh K; Shlyapov, R M; Uali, A S [Buketov Karaganda state university, University str., 28, Karaganda, 100028 (Kazakhstan)], E-mail: amerkhanova_sh@mail.ru

    2009-02-01

    The results of the studying of interactions in multicomponent systems 'polyvinyl alcohol (PVA) - rare-earth element ion - nitrate of sodium - water' are represented. It is established that for rubidium (I) ions temperature and ionic strength is render destroying action, and for yttrium (III) ions the influence of these factors has return character which is connected with features of an electronic structure of metal ion. It is revealed that a dominating role of non-electrostatic formation composed, hence, the formation of donor-acceptor connection of 'metal - ligand' occurs through atom of oxygen.

  14. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  15. Neutralization by metal ions of the toxicity of sodium selenide.

    Directory of Open Access Journals (Sweden)

    Marc Dauplais

    Full Text Available Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag⁺, Cd²⁺, Cu²⁺, Hg²⁺, Pb²⁺ and Zn²⁺, (ii metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co²⁺ and Ni²⁺ and, finally, (iii metal ions which do not afford protection and do not interact (Ca²⁺, Mg²⁺, Mn²⁺ or weakly interact (Fe²⁺ with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid (DTNB, the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds.

  16. Recent progress of task-specific ionic liquids in chiral resolution and extraction of biological samples and metal ions.

    Science.gov (United States)

    Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Kong, Yong; Pan, Yuanjiang

    2018-01-01

    Ionic liquids have been functionalized for modern applications. The functional ionic liquids are also called task-specific ionic liquids. Various task-specific ionic liquids with certain groups have been constructed and exploited widely in the field of separation. To take advantage of their properties in separation science, task-specific ionic liquids are generally used in techniques such as liquid-liquid extraction, solid-phase extraction, gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. This review mainly covers original research papers published in the last five years, and we will focus on task-specific ionic liquids as the chiral selectors in chiral resolution and as extractant or sensor for biological samples and metal ion purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Investigation of metal ions in fusion plasmas using emission spectroscopy

    International Nuclear Information System (INIS)

    Tale, I.

    2005-01-01

    Full text: The Latvian and Portugal Associations are performing development of advanced plasma - facing system using the liquid metal limiter. The objectives of this project require study of the influence of the liquid metal limiter on the main plasma parameters, including concentration of evaporated metal atoms in plasma. The fusion plasmas are related to the dense hot plasmas. The required average ion temperature according to the ITER project (International Thermonuclear Experimental Reactor) is 8,0 keV (9,3 x 10 7 0 K), the average electron temperature - 8,9 keV (1,04 x 10 8 0 K). Plasma temperature operated in the research tokamak ISSTOK, involved in testing of liquid metal limiter concept is considerably less, being of order of 10 50 K. The ionization degree of metal atoms considerably depends on the plasma ion temperature. Density of metal vapours in plasma can be estimated using the following two spectroscopic methods: The fluorescence of the multiple ionised metal ions in steady state concentration; The charge exchange emission during ionisation of evaporated metal ions. In the first step of development of testing system of metal vapours the equipment and instrumentation for charge exchange spectroscopy of Ga and In has been elaborated taking into account the following features of plasma emission. The Ga emission lines occur on the background high temperature plasma black body emission and stray light. Radial distribution of Ga in plasma in the facing plane of Ga flux is desirable

  18. Portable Multispectral Colorimeter for Metallic Ion Detection and Classification.

    Science.gov (United States)

    Braga, Mauro S; Jaimes, Ruth F V V; Borysow, Walter; Gomes, Osmar F; Salcedo, Walter J

    2017-07-28

    This work deals with a portable device system applied to detect and classify different metallic ions as proposed and developed, aiming its application for hydrological monitoring systems such as rivers, lakes and groundwater. Considering the system features, a portable colorimetric system was developed by using a multispectral optoelectronic sensor. All the technology of quantification and classification of metallic ions using optoelectronic multispectral sensors was fully integrated in the embedded hardware FPGA ( Field Programmable Gate Array) technology and software based on virtual instrumentation (NI LabView ® ). The system draws on an indicative colorimeter by using the chromogen reagent of 1-(2-pyridylazo)-2-naphthol (PAN). The results obtained with the signal processing and pattern analysis using the method of the linear discriminant analysis, allows excellent results during detection and classification of Pb(II), Cd(II), Zn(II), Cu(II), Fe(III) and Ni(II) ions, with almost the same level of performance as for those obtained from the Ultravioled and visible (UV-VIS) spectrophotometers of high spectral resolution.

  19. Portable Multispectral Colorimeter for Metallic Ion Detection and Classification

    Directory of Open Access Journals (Sweden)

    Mauro S. Braga

    2017-07-01

    Full Text Available This work deals with a portable device system applied to detect and classify different metallic ions as proposed and developed, aiming its application for hydrological monitoring systems such as rivers, lakes and groundwater. Considering the system features, a portable colorimetric system was developed by using a multispectral optoelectronic sensor. All the technology of quantification and classification of metallic ions using optoelectronic multispectral sensors was fully integrated in the embedded hardware FPGA ( Field Programmable Gate Array technology and software based on virtual instrumentation (NI LabView®. The system draws on an indicative colorimeter by using the chromogen reagent of 1-(2-pyridylazo-2-naphthol (PAN. The results obtained with the signal processing and pattern analysis using the method of the linear discriminant analysis, allows excellent results during detection and classification of Pb(II, Cd(II, Zn(II, Cu(II, Fe(III and Ni(II ions, with almost the same level of performance as for those obtained from the Ultravioled and visible (UV-VIS spectrophotometers of high spectral resolution.

  20. Phytoremediation: an overview of metallic ion decontamination from soil

    Energy Technology Data Exchange (ETDEWEB)

    Singh, O.V.; Labana, S.; Pandey, G.; Budhiraja, R.; Jain, R.K. [Inst. of Microbial Technology, Chandigarh (India)

    2003-07-01

    In recent years, phytoremediation has emerged as a promising ecoremediation technology, particularly for soil and water cleanup of large volumes of contaminated sites. The exploitation of plants to remediate soils contaminated with trace elements could provide a cheap and sustainable technology for bioremediation. Many modern tools and analytical devices have provided insight into the selection and optimization of the remediation process by plant species. This review describes certain factors for the phytoremediation of metal ion decontamination and various aspects of plant metabolism during metallic decontamination. Metal-hyperaccumulating plants, desirable for heavily polluted environments, can be developed by the introduction of novel traits into high biomass plants in a transgenic approach, which is a promising strategy for the development of effective phytoremediation technology. The genetic manipulation of a phytoremediator plant needs a number of optimization processes, including mobilization of trace elements/metal ions, their uptake into the root, stem and other viable parts of the plant and their detoxification and allocation within the plant. This upcoming science is expanding as technology continues to offer new, low-cost remediation options. (orig.)

  1. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    International Nuclear Information System (INIS)

    Lu, Yi

    2003-01-01

    The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize

  2. Adsorption of heavy metal ions by sawdust of deciduous trees

    International Nuclear Information System (INIS)

    Bozic, D.; Stankovic, V.; Gorgievski, M.; Bogdanovic, G.; Kovacevic, R.

    2009-01-01

    The adsorption of heavy metal ions from synthetic solutions was performed using sawdust of beech, linden and poplar trees. The adsorption depends on the process time, pH of the solution, type of ions, initial concentration of metals and the sawdust concentration in suspension. The kinetics of adsorption was relatively fast, reaching equilibrium for less than 20 min. The adsorption equilibrium follows Langmuir adsorption model. The ion exchange mechanism was confirmed assuming that the alkali-earth metals from the adsorbent are substituted by heavy metal ions and protons. On lowering the initial pH, the adsorption capacity decreased, achieving a zero value at a pH close to unity. The maximum adsorption capacity (7-8 mg g -1 of sawdust) was achieved at a pH between 3.5 and 5 for all the studied kinds of sawdust. The initial concentration of the adsorbate and the concentration of sawdust strongly affect the process. No influence of particles size was evidenced. A degree of adsorption higher than 80% can be achieved for Cu 2+ ions but it is very low for Fe 2+ ions, not exceeding 10%.

  3. Metal ion toxins and brain aquaporin-4 expression: an overview

    Directory of Open Access Journals (Sweden)

    Adriana eXimenes-Da-Silva

    2016-06-01

    Full Text Available Metal ions such as iron, zinc, and manganese are essential to metabolic functions, protein synthesis, neurotransmission, and antioxidant neuroprotective mechanisms. Conversely, non-essential metals such as mercury and lead are sources of human intoxication due to occupational activities or environmental contamination. Essential or non-essential metal accumulation in the central nervous system (CNS results in changes in blood-brain barrier (BBB permeability, as well as triggering microglia activation and astrocyte reactivity and changing water transport through the cells, which could result in brain swelling. Aquaporin-4 is the main water channel in the CNS, is expressed in astrocyte foot processes in brain capillaries and along the circumventricular epithelium in the ventricles, and has important physiological functions in maintaining brain osmotic homeostasis and supporting brain excitability through regulation of the extracellular space. Some evidence has pointed to a role of AQP4 during metal intoxication in the brain, where it may act in a dual form as a neuroprotector or a mediator of the development of oxidative stress in neurons and astrocytes, resulting in brain swelling and neuronal damage. This mini-review presents the way some metal ions affect changes in AQP4 expression in the CNS and discuss the ways in which water transport in brain cells can be involved in brain damage.

  4. Removal of heavy-metal ions from dilute waste streams using membrane-based hybrid systems

    International Nuclear Information System (INIS)

    Friesen, D.T.; Edlund, D.J.

    1993-01-01

    At Bend research, the authors have developed hybrid systems that couple a process that removes solvent (water) and a process that removes solute (metal ions) such that toxic heavy-metal ions can be efficiently and selectively removed to very low levels while simultaneously concentrating the heavy-metal ions in relatively pure form. Although this technology is broadly applicable, the authors are focusing on the development of a system to treat groundwater that is contaminated with heavy-metal ions. The process utilizes coupled transport and reverse osmosis to reduce chromium and uranium concentration down to parts-per-billion levels

  5. Application of monocarboxylic acids for the extraction of metal ions-literature survey

    International Nuclear Information System (INIS)

    Brzozka, Z.; Rozycki, C.

    1980-01-01

    In the paper there is presented a literature review concerning the application of monocarboxylic acids for extraction of metal ions. The following problems are discussed: characteristic of monocarboxylic acids and their mixtures, the equilibria between the acid solution in organic solvent and aqueous phase, the mechanism of acid partition, complexes of carboxylic acids and metal ions in aqueous phase, mechanism of extraction by means of carboxylic acids as well as the problems concerning the extraction of individual metal ions. Data about the extraction of metal ions are presented in table. The 138 references are given. (author)

  6. Modeling the adsorption of metal ions (Cu 2+, Ni 2+, Pb 2+) onto ACCs using surface complexation models

    Science.gov (United States)

    Faur-Brasquet, Catherine; Reddad, Zacaria; Kadirvelu, Krishna; Le Cloirec, Pierre

    2002-08-01

    Activated carbon cloths (ACCs), whose efficiency has been demonstrated for microorganics adsorption from water, were here studied in the removal of metal ions from aqueous solution. Two ACCs are investigated, they are characterized in terms of porosity parameters (BET specific surface area, percentage of microporosity) and chemical characteristics (acidic surface groups, acidity constants, point of zero charge). A first part consists in the experimental study of three metal ions removal (Cu 2+, Ni 2+ and Pb 2+) in a batch reactor. Isotherms modeling by Freundlich and Brunauer-Emmett-Teller (BET) equations enables the following adsorption order: Cu 2+>Ni 2+>Pb 2+ to be determined for adsorption capacities on a molar basis. It may be related to adsorbates characteristics in terms of electronegativity and ionic radius. The influence of adsorbent's microporosity is also shown. Adsorption experiments carried out for pH values ranging from 2 to 10 demonstrate: (i) an adsorption occurring below the precipitation pH; (ii) the strong influence of pH, with a decrease of electrostatic repulsion due to the formation of less charged hydrolyzed species coupled with a decrease of activated carbon surface charge as pH increases. The second part focuses on the modeling of adsorption versus the pH experimental data by the diffuse layer model (DLM) using Fiteql software. The model is efficient to describe the system behavior in the pH range considered. Regarding complexation constants, they show the following affinity for ACC: Pb 2+>Cu 2+>Ni 2+. They are related to initial concentrations used for the three metal ions.

  7. Complexation of metal ions with humic acid: charge neutralization model

    International Nuclear Information System (INIS)

    Kim, J.I.; Czerwinski, K.R.

    1995-01-01

    A number of different approaches are being used for describing the complexation equilibrium of actinide ions with humic or fulvic acid. The approach chosen and verified experimentally by Tu Muenchen will be discussed with notable examples from experiment. This approach is based on the conception that a given actinide ion is neutralized upon complexation with functional groups of humic or fulvic acid, e.g. carboxylic and phenolic groups, which are known as heterogeneously cross-linked polyelectrolytes. The photon energy transfer experiment with laser light excitation has shown that the actinide ion binding with the functional groups is certainly a chelation process accompanied by metal ion charge neutralization. This fact is in accordance with the experimental evidence of the postulated thermodynamic equilibrium reaction. The experimental results are found to be independent of origin of humic or fulvic acid and applicable for a broad range of pH. (authors). 23 refs., 7 figs., 1 tab

  8. Heating effects in a liquid metal ion source

    International Nuclear Information System (INIS)

    Mair, G.L.R.; Aitken, K.L.

    1984-01-01

    A reassessment is made of the heating occurring at the anode of a liquid metal ion source, in the light of new microscopic observations. The apex region of the cones is in the form of a cusp, or jet, even at very low currents. The calculation for ohmic heating is conclusive for low currents; no heating occurs at the anode; for high currents (approx. 50-100 μA), substantial heating is conceivable, if a long, very thin, cylindrical jet exists at the apex of the anode. The answer to the problem of external heating, in the form of electrons bombarding the anode, is not quite conclusive; this is because of the impossibility of correctly assessing the electron flux entering the anode. However, it would appear to be a definite conclusion that for reasons of self-consistency field-ionisation of thermally released atoms cannot be a significant ion emission mechanism. (author)

  9. Plasma immersion surface modification with metal ion plasma

    International Nuclear Information System (INIS)

    Brown, I.G.; Yu, K.M.; Godechot, X.

    1991-04-01

    We describe here a novel technique for surface modification in which metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including' conventional' high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way. 22 refs., 4 figs

  10. Extraction of metal ions by neutral β-diphosphoramides

    International Nuclear Information System (INIS)

    Madic, C.

    1990-01-01

    The extracting ability of β-diphosphoramides of the type R-N[P(O)(NMe 2 ) 2 ] 2 with R=-CH 3 (NIPA), -C 12 H 25 (ODIPA), or -C 16 H 33 (OHDIPA) for metal ions such as lanthanides, uranyl, and the transuranium elements Am(III) and Pu(IV) has been studied. Extraction yields depend on the nature of the ligand, the organic diluent (nitromethane, kerosene, tert-butylbenzene), the concentration of nitric acid in the aqueous phase, and the ligand-to-metal ratio, Q. The results show that the bidentate phosphoramides are very efficient extractants for all of the metals studied, even at low ratios Q. The presence of nitric acid generally enhances the extraction yields. On the other hand, selectivity is rather poor with these ligands. A particular effort has been made to determine the nature of extracted species by NMR spectroscopy

  11. Upgraded vacuum arc ion source for metal ion implantation

    International Nuclear Information System (INIS)

    Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu.; Brown, I. G.

    2012-01-01

    Vacuum arc ion sources have been made and used by a large number of research groups around the world over the past twenty years. The first generation of vacuum arc ion sources (dubbed ''Mevva,'' for metal vapor vacuum arc) was developed at Lawrence Berkeley National Laboratory in the 1980s. This paper considers the design, performance parameters, and some applications of a new modified version of this kind of source which we have called Mevva-V.Ru. The source produces broad beams of metal ions at an extraction voltage of up to 60 kV and a time-averaged ion beam current in the milliampere range. Here, we describe the Mevva-V.Ru vacuum arc ion source that we have developed at Tomsk and summarize its beam characteristics along with some of the applications to which we have put it. We also describe the source performance using compound cathodes.

  12. Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

    International Nuclear Information System (INIS)

    Mizuguchi, Hitoshi; Atsumi, Hiroshi; Hashimoto, Keigo; Shimada, Yasuhiro; Kudo, Yuki; Endo, Masatoshi; Yokota, Fumihiko; Shida, Junichi; Yotsuyanagi, Takao

    2004-01-01

    A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M 2 L) about a ligand in a narrow range of the total metal ion concentration (M T ) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M 2 L; and (iii) the absorption spectrum of M 2 L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M T would be readily controlled by the total ligand concentration (L T ). Based on this theory, the proposed model was verified with the 3,3'-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine

  13. Adsorption of heavy metal ions on activated carbon, (5)

    International Nuclear Information System (INIS)

    Yoshida, Hisayoshi; Kamegawa, Katsumi; Arita, Seiji

    1978-01-01

    The adsorption effect of heavy metal ions Cd 2+ , Zn 2+ and Hg 2+ on activated carbon by adding EDTA is reported, utilizing the experimental data. The activated carbons used for the experiment are mostly D, and B, C and F partly. As for the experimental procedure, the solutions of 100 ml which are composed of activated carbon, pH adjusting liquid, EDTA solution and solutions of heavy metals Cd, Zn and Hg, are shaken for 24 hours at 20 deg C, and after the activated carbon is centrifuged and separated for 15 minutes at 3000 rpm, the remaining heavy metal concentrations and pH in the supernatant are measured. The experimental results showed the useful effect on the adsorption of heavy metal ions of Cd, Zn and Hg by adding about 1 mol ratio of (EDTA/heavy metals). The individual experimental results are presented in detail. Concerning the adsorption quantity, 83% of Cd ions remained in the supernatant without addition of EDTA, but less than 1% with addition of about 1 to 5 mol ratio of (EDTA/Cd), and this adsorption effect was almost similar to Zn and Hg, i.e. 100% to 1% in Zn and 70% to 2 or 3% in Hg, under the condition written above. As for the influence of pH on Cd adsorption, the remaining Cd ratio is less than 10%, when pH is 7 to 10.5 at the mol ratio of 1 and 5.5 to 9 at the mol ratio of 10. The adsorption effect was different according to the kinds of activated carbon. The influencing factors for adsorption effect are the concentration of coexisting cations in the solution and the mixing time, etc. The effects of pH on Zn and Hg adsorption were almost similar to Cd. (Nakai, Y.)

  14. On the possibility of removing of transition metal ions from sewage using polymeric complexes

    International Nuclear Information System (INIS)

    Tazhibaeva, S.M.; Abilov, Zh.A.; Musabekov, K.V.

    1997-01-01

    The possibility of using of complexation in the system polyethylene-imine transition metal ions (Cu 2+ , Ni 2+ , Co 2+ )-surface active substance for removing of metal ions from solution and sewage has been investigated. It is shown, that pH of medium, hydro-fugitive of system and ratio between component of the triply complex effect on purification of solution. (author)

  15. Effect of transition metal ions on the conductivity and stability of stabilized zirconia

    DEFF Research Database (Denmark)

    Lybye, D.; Mogensen, Mogens Bjerg

    2007-01-01

    the effect of co-doping with smaller transition metal ions such as Ti-, Fe- and Mn-ions. Many of the ionic radii of the transition metal ions are too small compared to the host lattice ionic radius of zirconium. Here we explore the effect of a) the small ionic radii compared to the large ionic radii...

  16. New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Richard A.

    2012-06-04

    The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be performed. A unifying feature of the ligand structures is the presence of one (or more) side arm with a pendent acidic function. When a metal ion is complexed within the central cavity of the ligand, ionization of the side arm(s) produces the requisite anion(s) for formation of an overall electroneutral complex. This markedly enhances extraction/transport efficiency for separations in which movement of aqueous phase anions of chloride, nitrate, or sulfate into an organic medium would be required. Through systematic structural variations, new ligands have been developed for efficient and selective separations of monovalent metal ions (e.g., alkali metal, silver, and thallium cations) and of divalent metal ion species (e.g., alkaline earth metal, lead, and mercury cations). Research results obtained in these fundamental investigations provide important insight for the design and development of ligands suitable for practical metal ion separation applications.

  17. Effect of metal ions on the growth and metabolites production of ...

    African Journals Online (AJOL)

    Effect of metal ions on the growth and metabolites production of Ganoderma lucidum in submerged culture. YH Cui, KC Zhang. Abstract. The effects of several metal ions on the cell growth, production of polysaccharides by Ganoderma lucidum in submerged fermentation were studied. The results showed that 50 ppm Se2+ ...

  18. Effects of urea, metal ions and surfactants on the binding of baicalein with bovine serum albumin

    Directory of Open Access Journals (Sweden)

    Atanu Singha Roy

    2016-08-01

    Full Text Available The interaction of baicalein with bovine serum albumin (BSA was investigated with the help of spectroscopic and molecular docking studies. The binding affinity of baicalein towards BSA was estimated to be in order of 105 M−1 from fluorescence quenching studies. Negative ΔH° (−5.66±0.14 kJ/mol and positive (ΔS° (+79.96±0.65 J/mol K indicate the presence of electrostatic interactions along with the hydrophobic forces that result in a positive ΔS°. The hydrophobic association of baicalein with BSA diminishes in the presence of sodium dodecyl sulfate (SDS due to probable hydrophobic association of baicalein with SDS, resulting in a negative ΔS° (−40.65±0.87 J/mol K. Matrix-assisted laser desorption ionization/time of flight (MALDI--TOF experiments indicate a 1:1 complexation between baicalein and BSA. The unfolding and refolding phenomena of BSA were investigated in the absence and presence of baicalein using steady-state and fluorescence lifetime measurements. It was observed that the presence of urea ruptured the non-covalent interaction between baicalein and BSA. The presence of metal ions (Ag+, Mg2+, Ni2+, Mn2+, Co2+and Zn2+ increased the binding affinity of ligand towards BSA. The changes in conformational aspects of BSA after ligand binding were also investigated using circular dichroism (CD and Fourier transform infrared (FT-IR spectroscopic techniques. Site selectivity studies following molecular docking analyses indicated the binding of baicalein to site 1 (subdomain IIA of BSA.

  19. Selective transport of metal ions through cation exchange membrane in the presence of a complexing agent

    Energy Technology Data Exchange (ETDEWEB)

    Tingchia Huang; Jaukai Wang (National Cheng Kung Univ., Tainan (Taiwan, Province of China))

    1993-01-01

    Selective transport of metal ions through a cation exchange membrane was studied in stirred batch dialyzer for the systems Ni[sup 2+]-Cu[sup 2+] and Cu[sup 2+]-Fe[sup 3+]. Oxalic acid, malonic acid, citric acid, glycine, and ethylenediaminetetraacetic acid were employed as the complexing agents added in the feed solution in order to increase the permselectivity of metal ions. The experimental results show that the selective transport behavior of metal ions depends on the valence and the concentration of metal ions, the stoichiometric ratio of complexing agent to metal ions, and the pH value of the feed solution, but is independent of the concentration of counterion in the stripping phase. A theoretical approach was formulated on the basis of the Nernst-Planck equation and interface quasi-equilibrium. Theoretical solutions obtained from numerical calculation were in agreement with the experimental data.

  20. Adsorption of Heavy Metal Ions from Aqueous Solutions by Bentonite Nanocomposites.

    Science.gov (United States)

    Ma, Jing; Su, Guojun; Zhang, Xueping; Huang, Wen

    2016-08-01

    A series of bentonite nanocomposites have been synthesized by modifying bentonite with hexadecyltrimethylammonium bromide (CTMAB) and the common complexing agents, complexone (ethylene diamine tetraacetic acid, EDTA) or mercaptocomplexant (2-Mercaptobenzothiazole, MBT). These adsorbents are used to remove heavy metal ions (Cu(2+), Zn(2+), Mn(2+),Co(2+)). The Bent-CTMAB-MBT adsorbed metal ions are higher than Bent-CTMAB-EDTA under the same ion concentration in AAS. Compared with the single ion system, the adsorption of the mixed ion system of Cu(2+), Zn(2+), Mn(2+), Co(2+) had decreased differently. In the mixed system, the adsorption of Mn(2+) is significantly lower, but the adsorption of Cu(2+) was highest. The adsorption sequence of these four metal ions was Cu(2+) > Zn(2+) > Co(2+) > Mn(2+), and the selective adsorption was closely related to the hydration energy of heavy metal ions. We could remove more metal ions in different stages with the adsorption sequence.

  1. Effect of Heavy Metal Ions and Carbohydrates on the Activity of Cauliflower (Brassica oleracea Var. botrytis Myrosinase

    Directory of Open Access Journals (Sweden)

    Prakash, Om

    2013-04-01

    Full Text Available Myrosinase is an enzyme of cruciferous vegetables, hydrolyse glucosinolates. The breakdown products are involved in plant defence against insect and also have anti-fungal property. Myrosinase has been purified to apparent homogeneity from 5 days old germinated cauliflower seedlings having a specific activity of 12.71 units/mg proteins with 54.6 % recovery, using ammonium sulfate fractionation followed by gel filtration chromatography on Sephadex G-100. Effect of some metal ions and carbohydrates on the activity of partially purified cauliflower myrosinase was studied. Sr+2 at 4 mM concentration exhibited marked activating effect on the activity up to 2.7 fold while Fe+2 significantly inhibited. However, Sn+2 and Ba+2 increased the activity to a certain extent and then suppressed. On the other hand, some metal ions [Fe+2, Fe+3, Cu+2 and Zn+2] strongly inhibited the activity even at lower concentrations. Several carbohydrates viz., glucose, fructose, sucrose, maltose and sorbitol even at comparatively higher concentrations had little detectable inhibitory effects. Activation kinetics of myrosinase in presence of Sn+2 and Sr+2 were studied between 0- 20min. The rate of reaction was almost constant till 15 min and then slight deactivation was recorded at various concentrations used.

  2. Covalent modifications of the amyloid beta peptide by hydroxynonenal: Effects on metal ion binding by monomers and insights into the fibril topology.

    Science.gov (United States)

    Grasso, G; Komatsu, H; Axelsen, P H

    2017-09-01

    Amyloid β peptides (Aβ) and metal ions are associated with oxidative stress in Alzheimer's disease (AD). Oxidative stress, acting on ω-6 polyunsaturated fatty acyl chains, produces diverse products, including 4-hydroxy-2-nonenal (HNE), which can covalently modify the Aβ that helped to produce it. To examine possible feedback mechanisms involving Aβ, metal ions and HNE production, the effects of HNE modification and fibril formation on metal ion binding was investigated. Results indicate that copper(II) generally inhibits the modification of His side chains in Aβ by HNE, but that once modified, copper(II) still binds to Aβ with high affinity. Fibril formation protects only one of the three His residues in Aβ from HNE modification, and this protection is consistent with proposed models of fibril structure. These results provide insight into a network of biochemical reactions that may be operating as a consequence of oxidative stress in AD, or as part of the pathogenic process. Copyright © 2016. Published by Elsevier Inc.

  3. Protein scaffolds for selective enrichment of metal ions

    Science.gov (United States)

    He, Chuan; Zhou, Lu; Bosscher, Michael

    2016-02-09

    Polypeptides comprising high affinity for the uranyl ion are provided. Methods for binding uranyl using such proteins are likewise provided and can be used, for example, in methods for uranium purification or removal.

  4. Single step purification of recombinant proteins using the metal ion-inducible autocleavage (MIIA) domain as linker for tag removal.

    Science.gov (United States)

    Ibe, Susan; Schirrmeister, Jana; Zehner, Susanne

    2015-08-20

    For fast and easy purification, proteins are typically fused with an affinity tag, which often needs to be removed after purification. Here, we present a method for the removal of the affinity tag from the target protein in a single step protocol. The protein VIC_001052 of the coral pathogen Vibrio coralliilyticus ATCC BAA-450 contains a metal ion-inducible autocatalytic cleavage (MIIA) domain. Its coding sequence was inserted into an expression vector for the production of recombinant fusion proteins. Following, the target proteins MalE and mCherry were produced as MIIA-Strep fusion proteins in Escherichia coli. The target proteins could be separated from the MIIA-Strep part simply by the addition of calcium or manganese(II) ions within minutes. The cleavage is not affected in the pH range from 5.0 to 9.0 or at low temperatures (6°C). Autocleavage was also observed with immobilized protein on an affinity column. The protein yield was similar to that achieved with a conventional purification protocol. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Adsorption of heavy metal ions by activated charcoal

    International Nuclear Information System (INIS)

    Fujikawa, Mitsuo

    1978-01-01

    The adsorption effect was measured for several kinds of heavy metal ions, Pb 2+ , Cd 2+ , Cu 2+ and Zn 2+ by passing them through activated charcoal beds and changing the pH values of solutions. The test procedure is to keep the pH value of solution more than 10 at first, filter heavy metal hydroxide deposit, measure the remaining ion concentration in filtrate, and also test the influence of the addition of alkali to each kind of ions. The individual test procedure for each kind of ions is explained. As for the Cd ions, after the detailed experimental procedure is explained, the adsorption characteristic line is shown as the relation between the adsorption quantity and the equilibrium concentration of Cd 2+ . The similar test procedure and the adsorption characteristic lines are shown and evaluated about Pb 2+ , Cu 2+ and Zn 2+ . These lines are all linear, but have different adsorption quantity and inclination in relation to heavy metal ion concentration. Concerning the influence of pH to adsorption, the characteristics of pH increase are presented, when alkali is added by various quantities to Zn 2+ , Cu 2+ , Pb 2+ and Cd 2+ . The pH of Pb 2+ increased to about 10 by adding 0.4 cc alkali and saturates, but the pH of the other ions did not saturate by adding less than 1.5 cc alkali. When the water containing heavy metals are treated, Cd 2+ , Pb 2+ , Cu 2+ and Zn 2+ are removed almost satisfactorily by passing them through active charcoal filters and keeping pH at 10. The experimental concentrations are 0.05 ppm at pH 10 in Cd, 0.86 ppm at 10.3 in Pb, 0 ppm at pH 9.6 in Cu, 0.06 ppm at pH 8.8 and 12.4 ppm at pH 9.8 in Zn. (Nakai, Y.)

  6. Metal ion protection of DNA to fast neutron irradiation

    International Nuclear Information System (INIS)

    Constantinescu, B.; Bugoi, R.; Radulescu, I.; Radu, L.

    1998-01-01

    The most important effects of the ionising radiation are the single and double strand breaks (SSB and DBS), modifications of the DNA bases and deoxyribose, as well as the occurrence of alkali and heat labile sites (revealed as strand breaks after alkaline or thermic treatment of irradiated DNA). The ionising particles can have either direct effects on the DNA constituents or indirect effects, mediated by the OH - radicals, produced by water radiolysis. The occurrence of SSB and DSB in the chromatin DNA strands is supposed to hinder the DNA-dye complex formation. Usually, the dyes present different fluorescence parameters in the two possible states, so one can correlate the lifetime or the quantum yield with the extent of the damage. We took into account the protective effect offered both by histones, which behave as 'scavenger molecules' for OH - radicals and by the high compactness of DNA chromatin. Similar protective effects might be the results of the metallic ion addition which triggers some conformational transitions of the chromatin DNA towards a highly compacted structure. In this paper we present a study of the complexes of fast neutron irradiated chromatin with proflavine. Fluorimetric and time resolved spectroscopic determinations (single photon counting method) of chromatin-Pr complexes were realised. Information regarding the chromatin protein damage were obtained by monitoring the fluorescence of Trp. The chromatin was irradiated (20-100 Gy) with fast neutrons, obtained by the reaction of 13.5 MeV deuterons on a thick beryllium target at the IFIN-HH U-120 Cyclotron. The dose mean lineal energy in water at the point of interest was 50 keV/m and the mean dose rate was 1.5 Gy/min. By fluorescence determinations, changes of the Pr intercalation parameters in fast neutron irradiated chromatin DNA have been observed. Fluorescence techniques provide valuable information on the binding equilibrium by considering the radiation deexcitation of the complex. The

  7. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

    2015-01-01

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

  8. Development of sensitive holographic devices for physiological metal ion detection

    Science.gov (United States)

    Sabad-e.-Gul; Martin, Suzanne; Cassidy, John; Naydenova, Izabela

    2017-08-01

    The development of selective alkali metal ions sensors in particular is a subject of significant interest. In this respect, the level of blood electrolytes, particularly H+, Na+, K+ and Cl- , is widely used to monitor aberrant physiologies associated with pulmonary emphysema, acute and chronic renal failure, heart failure, diabetes. The sensors reported in this paper are created by holographic recording of surface relief structures in a self-processing photopolymer material. The structures are functionalized by ionophores dibenzo-18-crown-6 (DC) and tetraethyl 4-tert-butylcalix[4]arene (TBC) in plasticised polyvinyl chloride (PVC) matrix. Interrogation of these structures by light allows indirect measurements of chemical analytes' concentration in real time. We present results on the optimisation and testing of the holographic sensor. A self-processing acrylamide-based photopolymer was used to fabricate the required photonic structures. The performance of the sensors for detection of K+ and Na+ was investigated. It was observed that the functionalisation with DC provides a selective response of the devices to K+ over Na+ and TBC coated surface structures are selectively sensitive to Na+. The sensor responds to Na+ within the physiological ranges. Normal levels of Na+ and K+ in human serum lie within the ranges 135-148mM and 3.5-5.3 mM respectively.

  9. Broad-beam, high current, metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1990-07-01

    We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the 'seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs

  10. Heavy metal ion removal by adsorption on to biological materials

    International Nuclear Information System (INIS)

    Jansson-Charrier, M.; Guibal, E.; Le Cloirec, P.; Surjous, R.

    1994-01-01

    The development of regulations constraints in the industrial waste-waters management leads to the study of new treatment processes, using raw or functionalized biological materials. These processes show competitive performances in metal ion sorption efficiency for the low metal content effluents. Uptake capacities of Uranium as high as 400 mg.g -1 chitosan, equivalent to the double of the uptake capacity of fungal origin biomass, can be reached. The application of these processes to real mine wastewaters gives efficiency coefficient upper to 90%, the residual concentrations are compatible to a direct injection into the environment. The grafting of functional groups onto the chitosan scales up the sorption performances to uptake capacity upper than 600 mg.g -1 polymer. pH, metal concentration are cited as major parameters, particle size influences both uptake kinetics and sorption equilibrium, in the case of the uranium accumulation by chitosan. The desorption of uranium from the sorbent allows the valorization of uranium and the re-use of the sorbent. (authors). 21 refs., 10 figs

  11. Partitioning-separation of metal ions using heterocyclic ligands

    International Nuclear Information System (INIS)

    Hudson, M.J.; Drew, M.G.B.; Iveson, P.B.; Russell, M.L.

    2001-01-01

    Some guidelines are proposed for the effective design of heterocyclic ligands for partitioning because there is no doubt that the correct design of a molecular extractant is required for the effective separation of metal ions such as actinides(III) from lanthanides(III). Heterocyclic ligands with aromatic ring systems have a rich chemistry, which is only now becoming sufficiently well understood in relation to the partitioning process. The synthesis, characterisation and structures of some chosen molecules will be introduced in order to illustrate some important features. For example, the molecule N-carboxy-butyl-2-amino-4,6-di (2-pyridyl)-1,3,5-triazine (BADPTZ), which is an effective solvent extraction reagent for actinides and lanthanides, has been synthesised, characterised and its interaction with lanthanide ions studied. The interesting and important features of this molecule will be compared with those of other heterocyclic molecules such as 2,6-bis(5-butyl-1,2,4-triazole-3-yl) pyridine (DBTZP), which is a candidate molecule for the commercial separation of actinides and lanthanide elements. (author)

  12. Organodioxygen complexes of some group 4B metal ions

    International Nuclear Information System (INIS)

    Tarafder, M.T.H.; Akhter Hossain; Gino Mariotto

    2003-09-01

    Organodioxygen complexes of some group 4B metal ions, viz., zirconium(IV), tin(IV) and lead(II) containing monodentate, bidentate and tridentate ligands were synthesized and characterized. The complexes have the compositions of [Zr(O)(O 2 )2C 5 H 5 N.H 2 O], [Zr(O)(O 2 - ) 2 .2OPPh 3 ], [Sn(O 2 )(C 9 H 6 NO) 2 ], [Sn(0 2 ) 2 .(CH 2 ) 2 (NH 2 ) 2 ], [Pb(O 2 - )(C 5 H 5 N) 2 NO 3 ], [Pb(O 2 )(C 8 H 6 NOH)], [Pb(O 2 - )(det)NO 3 ] and [PbO 2 - ) (C 5 H 4 NCOOH)NO 3 .H 2 O]. Because of apparent linearity of M- O 2 grouping, the V 1 (O-O) stretching modes were only Raman active, giving bands at 810- 841 cm 1 for the peroxo complexes (1, 3, ,4 and 6), while the bands in the superoxo complexes (2, 5, 7 and 8) appeared at 1020- 1100 cm -1 . The peroxo complex of Zr(IV) containing monodentate ligands were found to oxidize trans-stilbene to trans-stilbene oxide under stoichiometric conditions. The organoperoxo complexes of tin and lead were insensitive to oxidative processes. (author)

  13. Multi stage electrodialysis for separation of two metal ion species

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, K.; Sakurai, H.; Nii, S.; Sugiura, K. [Nagoya Univ., Nagoya (Japan)

    1995-04-20

    In this article, separation of two metal ions by electrodialysis with a cation exchange membrane has been investigated. In other words, separation of potassium ion and sodium ion has been investigated by using batch dialysis with and without an electric field and continuous electrodialysis with a four-stage dialyzer. As a result, the difference in the permselectivity between the dialysis with and without an electric field has not been appreciable for the system of potassium and sodium ions with the cation exchange membrane. Concerning the continuous electrodialysis, the concentration ratio between potassium and sodium ions in the outlet solution from the recovery side of the dialyzer has increased with the reflux flow rate and the number of stages. In case when the reflux flow rate has been zero, the concentration ratio with the four-stage dialyzer has become 1.5 which is almost the same as with that with a two-stage dialyzer consisting of a simple membrane. When the reflux flow ratio has been 0.7, the concentration ratio has reached 3.6. 20 refs., 8 figs.

  14. A theoretical model of a liquid metal ion source

    International Nuclear Information System (INIS)

    Kingham, D.R.; Swanson, L.W.

    1984-01-01

    A model of liquid metal ion source (LMIS) operation has been developed which gives a consistent picture of three different aspects of LMI sources: (i) the shape and size of the ion emitting region; (ii) the mechanism of ion formation; (iii) properties of the ion beam such as angular intensity and energy spread. It was found that the emitting region takes the shape of a jet-like protrusion on the end of a Taylor cone with ion emission from an area only a few tens of A across, in agreement with recent TEM pictures by Sudraud. This is consistent with ion formation predominantly by field evaporation. Calculated angular intensities and current-voltage characteristics based on our fluid dynamic jet-like protrusion model agree well with experiment. The formation of doubly charged ions is attributed to post-ionization of field evaporated singly charged ions and an apex field strength of about 2.0 V A -1 was calculated for a Ga source. The ion energy spread is mainly due to space charge effects, it is known to be reduced for doubly charged ions in agreement with this post-ionization mechanism. (author)

  15. The effects of heavy metal ions on the chlorophyll content and cell membrane permeability of charophytes

    International Nuclear Information System (INIS)

    Fu Hualong; Chen Hao; Dong Bin; Qing Renwei

    2001-01-01

    The authors studied the effects of several heavy metal ions in different concentrations (Cd 2+ , Hg 2+ , Pb 2+ , Cr 6+ ) on the chlorophyll content and cell membrane permeability of Chara vulgaris L. It was discovered that the effects of heavy metal ions on the chlorophyll content and cell membrane permeability of Chara vulgaris L. changed with their different concentration. The trend was that the chlorophyll content and cell membrane permeability were decreased with the increase of the heavy metal ions. The degree of chlorophyll content affected was Cr 6+ , Cd 2+ , Hg 2+ , Pb 2+ , and that of cell membrane permeability affected was Cd 2+ , Cr 6+ , Hg 2+ , Pb 2+

  16. Removal and recovery of metal ions from process and waste streams using polymer filtration

    International Nuclear Information System (INIS)

    Jarvinen, G.D.; Smith, B.F.; Robison, T.W.; Kraus, K.M.; Thompson, J.A.

    1999-01-01

    Polymer Filtration (PF) is an innovative, selective metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to aqueous streams from nuclear materials processing and electroplating operations will be described

  17. Accelerated electron exchange between U4+ and UO22+ by foreign metal ions

    International Nuclear Information System (INIS)

    Obanawa, Heiichiro; Onitsuka, Hatsuki; Takeda, Kunihiko

    1990-01-01

    The rate constant of U 4+ -UO 2 2+ electron exchange (k et ) was increased by more than 100 times in the presence of various metal ions. The larger rate constant was observed for the smaller difference of the standard reduction potential strength between metal ion and UO 2 2+ ion (Δμ θ e ). Detailed investigation of the electron exchange reaction in the presence of Mo 5+ suggested that the mechanism of the electron transfer reaction catalyzed by metal ions is the outer-sphere type independent of U-Clcomplex ions. (author)

  18. Ultra-fast liquid chromatography with tandem mass spectrometry determination of ochratoxin A in traditional Chinese medicines based on vortex-assisted solid-liquid microextraction and aptamer-affinity column clean-up.

    Science.gov (United States)

    Yang, Xihui; Hu, Yichen; Kong, Weijun; Chu, Xianfeng; Yang, Meihua; Zhao, Ming; Ouyang, Zhen

    2014-11-01

    A rapid, selective, and sensitive ultra-fast liquid chromatography with tandem mass spectrometry method was developed for the determination of ochratoxin A in traditional Chinese medicines based on vortex-assisted solid-liquid microextraction and aptamer-affinity column clean-up. Through optimizing the sample pretreatment procedures and chromatographic conditions, good linearity (r(2) ≥ 0.9993), low limit of detection (0.5-0.8 μg/kg), and satisfactory recovery (83.54-94.44%) expressed the good reliability and applicability of the established method in various traditional Chinese medicines. Moreover, the aptamer-affinity column, prepared in-house, showed an excellent feasibility owing to its specific identification of ochratoxin A in various kinds of selected traditional Chinese medicines. The maximum adsorption amount and applicability value were 188.96 ± 10.56 ng and 72.3%, respectively. The matrix effects were effectively eliminated, especially for m/z 404.2→358.0 of ochratoxin A. The application of the developed method for screening the natural contamination levels of ochratoxin A in 25 random traditional Chinese medicines on the market in China indicated that only eight samples were contaminated with low levels below the legal limit (5.0 μg/kg) set by the European Union. This study provided a preferred choice for the rapid and accurate monitoring of ochratoxin A in complex matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A highly selective dispersive liquid-liquid microextraction approach based on the unique fluorous affinity for the extraction and detection of per- and polyfluoroalkyl substances coupled with high performance liquid chromatography tandem-mass spectrometry.

    Science.gov (United States)

    Wang, Juan; Shi, Yali; Cai, Yaqi

    2018-04-06

    In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF 2  > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF 2  > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere

    Science.gov (United States)

    Mathews, J. D.

    1987-01-01

    The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed.

  1. Development of a method employing chitosan to remove metallic ions from wastewater

    International Nuclear Information System (INIS)

    Janegitz, Bruno Campos; Lourencao, Bruna Claudia; Lupetti, Karina Omuro; Fatibello-Filho, Orlando

    2007-01-01

    In this work a method was developed for removing metallic ions from wastewaters by co-precipitation of Cu 2+ , Pb 2+ , Cd 2+ , Cr 3+ and Hg 2+ with chitosan and sodium hydroxide solution. Solutions of these metallic ions in the range from 0.55 to 2160 mg L -1 were added to chitosan dissolved in 0.05 mol L -1 HCl. For the co-precipitation of metal-chitosan-hydroxide a 0.17 mol L -1 NaOH solution was added until pH 8.5-9.5. A parallel study was carried out applying a 0.17 mol L -1 NaOH solution to precipitate those metallic ions. Also, a chitosan solid phase column was used for removing those metallic ions from wastewaters. (author)

  2. A computational study of adsorption of divalent metal ions on graphene oxide

    Directory of Open Access Journals (Sweden)

    Somphob Thompho

    2017-12-01

    Full Text Available Adsorption of divalent metal ions (Pb2+,Cd2+, Zn2+,Cu2+ on graphene oxide (GO was studied using density functional theory (DFT. Adsorption geometries and energies, as well as the nature of the binding energy, were calculated for the interaction of divalent metal ions with oxygen-containing groups on the surface of GO. The configurations of the complexes were modeled by placing the divalent metal ions above the center and perpendicular to the surface. Binding of Cu2+ to the GO sheet was predicted to be much stronger than that for other divalent metal ions. Calculated results show good agreement with experimental observations and provide useful information for environmental pollution cleanup.

  3. Multiheteromacrocycles that complex metal ions. Third progress report, 1 May 1976--30 April 1977

    International Nuclear Information System (INIS)

    Cram, D.J.

    1977-01-01

    The overall objective of this research is to design, synthesize and evaluate cyclic and polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions, their complexes and clusters. Host organic compounds consist of strategically placed solvating, coordinating and ion-pairing sites tied together by covalent bonds through hydrocarbon units around cavities shaped to be occupied by guest metal ions, or metal ions plus their ligands. Specificity in complexation is sought by matching the following properties of host and guest: cavity and metal ion sizes; geometric arrangements of binding sites; numbers of binding sites; characters of binding sites; and valences. The specific compounds synthesized and their complexing and lipophilizing properties are summarized

  4. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue; Ge, Qingchun; Liu, Xiangyang; Chung, Neal Tai-Shung

    2014-01-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  5. Prostate cancer outcome and tissue levels of metal ions

    Science.gov (United States)

    Sarafanov, A.G.; Todorov, T.I.; Centeno, J.A.; MacIas, V.; Gao, W.; Liang, W.-M.; Beam, C.; Gray, Marion A.; Kajdacsy-Balla, A.

    2011-01-01

    BACKGROUNDThere are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome.METHODSWe obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case–control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se.RESULTSPatients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 µg/g vs. 111 µg/g; P = 0.04) and 21% lower zinc (279 µg/g vs. 346 µg/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 µg/g vs. 0.439 µg/g; 4% higher) and selenium (1.68 µg/g vs. 1.58 µg/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively).CONCLUSIONSThere is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. 

  6. Novel forward osmosis process to effectively remove heavy metal ions

    KAUST Repository

    Cui, Yue

    2014-10-01

    In this study, a novel forward osmosis (FO) process for the removal of heavy metal ions from wastewater was demonstrated for the first time. The proposed FO process consists of a thin-film composite (TFC) FO membrane made from interfacial polymerization on a macrovoid-free polyimide support and a novel bulky hydroacid complex Na4[Co(C6H4O7)2]·r2H2O (Na-Co-CA) as the draw solute to minimize the reverse solute flux. The removal of six heavy metal solutions, i.e., Na2Cr2O7, Na2HAsO4, Pb(NO3)2, CdCl2, CuSO4, Hg(NO3)2, were successfully demonstrated. Water fluxes around 11L/m2/h (LMH) were harvested with heavy metals rejections of more than 99.5% when employing 1M Na-Co-CA as the draw solution to process 2000ppm(1 ppm=1 mg/L) heavy metal solutions at room temperature. This FO performance outperforms most nanofiltration (NF) processes. In addition, the high rejections were maintained at 99.5% when a more concentrated draw solution (1.5M) or feed solution (5000ppm) was utilized. Furthermore, rejections greater than 99.7% were still achieved with an enhanced water flux of 16.5LMH by operating the FO process at 60°C. The impressive heavy metal rejections and satisfactory water flux under various conditions suggest great potential of the newly developed FO system for the treatment of heavy metal wastewater. © 2014 Elsevier B.V.

  7. thermodynamic and kinetic evaluations of some heavy metal ions

    African Journals Online (AJOL)

    CHIDEXCOM

    The adsorption isotherm fitted well with Langmuir equation model for the acid – modified than the .... aqueous phase in mg l-1, qm is the qe for a complete monolayer in mg g-1, kL is a constant related to the affinity of the binding sites and ...

  8. Understanding interaction of curcumin and metal ions on electrode surfaces using EDXRF

    Science.gov (United States)

    Joseph, Daisy; Kumar, K. Krishna; Narayanan, S. Sriman

    2018-04-01

    A chemically modified electrode was developed for determination of metal ions (Cd, Pb, Zn, Co, Hg). The modifier used for the study was Curcumin. Curcumin acts as a complexing agent at the surface of the electrode for preconcentration of metal ions from electrolyte to electrode surface and stripped back to electrolyte during analysis. EDXRF was used to analyze these electrodes and it was concluded that the PCR modified electrode favored effective chelation for lead and mercury.

  9. Metal ion separations with proton-ionizable Lariat Ethers and their polymers

    International Nuclear Information System (INIS)

    Bartsch, R.A.

    1993-01-01

    The preparation of novel and specific organic complexing agents may lead to the development of new separation systems for aqueous metal ions. Thus the introduction of highly lipophilic oximes led to the current utilization of these compounds as commercial extractants for the hydrometallurgy of nonferrous metals. Crown ethers (macrocyclic polyethers) have been employed in the laboratory-scale solvent extraction of alkali-metal, alkaline-earth, and other metal cations into organic phases. Attachment of side arms to crown ethers gives lariat ethers. The presence of one or more potential coordination sites in the side arm of the lariat ether may produce substantial changes in the selectivity and efficiency of metal ion complexation. It has been demonstrated that concomitant transfer of an aqueous phase anion into the organic medium is not required for metal ion extraction. This factor is of immense importance to potential practical applications of these proton-ionizable crown ethers in which the common, hard, aqueous phase anions would be involved. Another advantage of proton-ionizable lariat ethers is the ease with which extracted metal ions may be stripped from the organic phase by shaking with aqueous mineral acid. Thus both metal ion extraction and stripping are facilitated by pendent proton-ionizable groups. Most of the hazardous metal ion species in the Hanford Site tank wastes are members of the alkali-metal, alkaline-earth, lanthanide, and actinide families. These hard metal ion species prefer association with hard donor atoms, such as oxygens. Therefore, crown and lariat ethers are well-suited for complexation with such metal ion species

  10. Linen Fire as Biosorbent to Remove Heavy Metal Ions From Wastewater Modeling

    OpenAIRE

    Ildar G. Shaikhiev

    2014-01-01

    The possibility of using linen fires – lnopererabotk i waste as a sorption material for the extraction of heavy metal ions from wastewater modeling. It is shown that treatment with acid solutions linen fires a low concentration increases the surface area of linen fires and thus sorption capacity for heavy metal ions. The values of the maximum sorption capacity ions Fe (III), Co (II), Ni (II) and Zn (II) under static and dynamic conditions. IR spectroscopy...

  11. Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

    CERN Document Server

    Dash, Monika

    2013-01-01

    Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

  12. Development of complexation ion chromatography for the determination of metal ions

    OpenAIRE

    Bashir, Wasim

    2002-01-01

    A simple ion chromatographic method was developed for the determination of Pb(II) in river and polluted water samples. The method was based upon the use of a colourforming complexing eluent and direct visible detection of the eluting Pb(II) complex. Using the combination of a strong cation exchange column and an eluent consisting of 20 mM sodium acetate-acetic acid buffer and 0.2 mM xylenol orange (XO) (~pH = 4.2), Pb(II) was detected at 572 nm eluting in under 6.5 min. The developed method p...

  13. Synthesis, vibrational spectrometry and thermal characterizations of coordination polymers derived from divalent metal ions and hydroxyl terminated polyurethane as ligand

    Science.gov (United States)

    Laxmi; Khan, Shabnam; Kareem, Abdul; Zafar, Fahmina; Nishat, Nahid

    2018-01-01

    A series of novel coordination polyurethanes [HTPU-M, where M = Mn(II) 'd5', Ni(II) 'd8', and Zn(II) 'd10'] have been synthesized to investigate the effect of divalent metal ions coordination on structure, thermal and adsorption properties of low molecular weight hydroxyl terminated polyurethane (HTPU). HTPU-M have been synthesized in situ where, sbnd OH group of HTPU (synthesized by the condensation polymerization reaction of ethylene glycol (EG) and toluene diisocyanate (TDI) in presence of catalyst) on condensation polymerization with metal acetate in presence of acid catalyst synthesized HTPU-M followed by coordination of metal ions with hetero atoms. The structure, composition and geometry of HTPU-M have been confirmed by vibrational spectrometry (FTIR), 1H NMR, elemental analysis and UV-Visible spectroscopy. Morphological structures of HTPU-M were analyzed by X-Ray Diffraction analysis (XRD), Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray spectroscopy (EDX) and High Resolution Transmission Electron Microscope (HR-TEM) techniques. The thermal degradation pattern and thermal stability of HTPU-M in comparison to HTPU was investigated by thermal-gravimetric (TG)/differential thermal (DT), analyses along with Integral procedure decomposition temperature (IPDT) by Doyle method. The molecular weight of HTPU was determined by gel permeation chromatography (GPC). The preliminary adsorption/desorption studies of HTPU-M for Congo red (CR) was studied by batch adsorption techniques. The results indicated that HTPU-M have amorphous, layered morphology with higher number of nano-sized grooves in comparison to HTPU. Coordination of metal to HTPU plays a key role in enhancing the thermal stability [HTPU-Ni(II) > HTPU-Mn(II) > HTPU-Zn(II) > HTPU]. The HTPU-M can be utilized for industrial waste water treatment by removing environmental pollutants.

  14. Role of DNA Repair Factor Xeroderma Pigmentosum Protein Group C in Response to Replication Stress As Revealed by DNA Fragile Site Affinity Chromatography and Quantitative Proteomics.

    Science.gov (United States)

    Beresova, Lucie; Vesela, Eva; Chamrad, Ivo; Voller, Jiri; Yamada, Masayuki; Furst, Tomas; Lenobel, Rene; Chroma, Katarina; Gursky, Jan; Krizova, Katerina; Mistrik, Martin; Bartek, Jiri

    2016-12-02

    Replication stress (RS) fuels genomic instability and cancer development and may contribute to aging, raising the need to identify factors involved in cellular responses to such stress. Here, we present a strategy for identification of factors affecting the maintenance of common fragile sites (CFSs), which are genomic loci that are particularly sensitive to RS and suffer from increased breakage and rearrangements in tumors. A DNA probe designed to match the high flexibility island sequence typical for the commonly expressed CFS (FRA16D) was used as specific DNA affinity bait. Proteins significantly enriched at the FRA16D fragment under normal and replication stress conditions were identified using stable isotope labeling of amino acids in cell culture-based quantitative mass spectrometry. The identified proteins interacting with the FRA16D fragment included some known CFS stabilizers, thereby validating this screening approach. Among the hits from our screen so far not implicated in CFS maintenance, we chose Xeroderma pigmentosum protein group C (XPC) for further characterization. XPC is a key factor in the DNA repair pathway known as global genomic nucleotide excision repair (GG-NER), a mechanism whose several components were enriched at the FRA16D fragment in our screen. Functional experiments revealed defective checkpoint signaling and escape of DNA replication intermediates into mitosis and the next generation of XPC-depleted cells exposed to RS. Overall, our results provide insights into an unexpected biological role of XPC in response to replication stress and document the power of proteomics-based screening strategies to elucidate mechanisms of pathophysiological significance.

  15. Two Divalent Metal Ions and Conformational Changes Play Roles in the Hammerhead Ribozyme Cleavage Reaction

    Science.gov (United States)

    Mir, Aamir; Chen, Ji; Robinson, Kyle; Lendy, Emma; Goodman, Jaclyn; Neau, David; Golden, Barbara L.

    2016-01-01

    The hammerhead ribozyme is a self-cleaving RNA broadly dispersed across all kingdoms of life. Although it was the first of the small, nucleolytic ribozymes discovered, the mechanism by which it catalyzes its reaction remains elusive. The nucleobase of G12 is well positioned to be a general base, but it is unclear if or how this guanine base becomes activated for proton transfer. Metal ions have been implicated in the chemical mechanism, but no interactions between divalent metal ions and the cleavage site have been observed crystallographically. To better understand how this ribozyme functions, we have solved crystal structures of wild-type and G12A mutant ribozymes. We observe a pH-dependent conformational change centered around G12, consistent with this nucleotide becoming deprotonated. Crystallographic and kinetic analysis of the G12A mutant reveals a Zn2+ specificity switch suggesting a direct interaction between a divalent metal ion and the purine at position 12. The metal ion specificity switch and the pH–rate profile of the G12A mutant suggest that the minor imino tautomer of A12 serves as the general base in the mutant ribozyme. We propose a model in which the hammerhead ribozyme rearranges prior to the cleavage reaction, positioning two divalent metal ions in the process. The first metal ion, positioned near G12, becomes directly coordinated to the O6 keto oxygen, to lower the pKa of the general base and organize the active site. The second metal ion, positioned near G10.1, bridges the N7 of G10.1 and the scissile phosphate and may participate directly in the cleavage reaction. PMID:26398724

  16. Real-time detection of metal ions using conjugated polymer composite papers.

    Science.gov (United States)

    Lee, Ji Eun; Shim, Hyeon Woo; Kwon, Oh Seok; Huh, Yang-Il; Yoon, Hyeonseok

    2014-09-21

    Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, -0.5, and -1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices.

  17. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  18. Effects of metal ions on growth, β-oxidation system, and thioesterase activity of Lactococcus lactis.

    Science.gov (United States)

    Li, Liang; Ma, Ying

    2014-10-01

    The effects of divalent metal ions (Ca(2+), Mg(2+), Fe(2+), and Cu(2+)) on the growth, β-oxidation system, and thioesterase activity of Lactococcus lactis were investigated. Different metal ions significantly influenced the growth of L. lactis: Ca(2+) and Fe(2+) accelerated growth, whereas Cu(2+) inhibited growth. Furthermore, Mg(2+) inhibited growth of L. lactis at a low concentration but stimulated growth of L. lactis at a high concentration. The divalent metal ions had significant effects on activity of the 4 key enzymes of the β-oxidation system (acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and thiolase) and thioesterase of L. lactis. The activity of acyl-CoA dehydrogenases increased markedly in the presence of Ca(2+) and Mg(2+), whereas it decreased with 1 mmol/L Fe(2+) or 12 mmol/L Mg(2+). All the metal ions could induce activity of enoyl-CoA hydratase. In addition, 12 mmol/L Mg(2+) significantly stimulated activity of L-3-hydroxyacyl-CoA dehydrogenase, and all metal ions could induce activity of thiolase, although thiolase activity decreased significantly when 0.05 mmol/L Cu(2+) was added into M17 broth. Inhibition of thioesterase activity by all 4 metal ions could be reversed by 2 mmol/L Ca(2+). These results help us understand the effect of metal ions on the β-oxidation system and thioesterase activity of Lactococcus lactis. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Density functional study of isoguanine tetrad and pentad sandwich complexes with alkali metal ions.

    Science.gov (United States)

    Meyer, Michael; Steinke, Thomas; Sühnel, Jürgen

    2007-02-01

    Isoguanine tetraplexes and pentaplexes contain two or more stacked polyads with intercalating metal ions. We report here the results of a density functional study of sandwiched isoguanine tetrad and pentad complexes consisting of two polyads with Na(+), K(+) and Rb(+) ions at the B3LYP level. In comparison to single polyad metal ion complexes, there is a trend towards increased non-planarity of the polyads in the sandwich complexes. In general, the pentad sandwiches have relatively planar polyad structures, whereas the tetrad complexes contain highly non-planar polyad building blocks. As in other sandwich complexes and in metal ion complexes with single polyads, the metal ion-base interaction energy plays an essential role. In iG sandwich structures, this interaction energy is slightly larger than in the corresponding guanine sandwich complexes. Because the base-base interaction energy is even more increased in passing from guanine to isoguanine, the isoguanine sandwiches are thus far the only examples where the base-base interaction energy is larger than the base-metal ion interaction energy. Stacking interactions have been studied in smaller models consisting of two bases, retaining the geometry from the complete complex structures. From the data obtained at the B3LYP and BH&H levels and with Møller-Plesset perturbation theory, one can conclude that the B3LYP method overestimates the repulsion in stacked base dimers. For the complexes studied in this work, this is only of minor importance because the direct inter-tetrad or inter-pentad interaction is supplemented by a strong metal ion-base interaction. Using a microsolvation model, the metal ion preference K(+) approximately Rb(+) > Na(+) is found for tetrad complexes. On the other hand, for pentads the ordering is Rb(+) > K(+) > Na(+). In the latter case experimental data are available that agree with this prediction.

  20. PSEUDOAFFINITY CHROMATOGRAPHY ENRICHMENT OF GLYCATED PEPTIDES FOR MONITORING ADVANCED GLYCATION END PRODUCTS (AGES IN METABOLIC DISORDERS

    Directory of Open Access Journals (Sweden)

    Rajasekar R. Prasanna

    2016-09-01

    Full Text Available Advanced Glycation End (AGE products are produced due to diabetic progression and they are responsible for many complications in the diabetic disorder. The diabetic progression is measured, particularly following glycated hemoglobin using specific antibodies. However, the most abundant protein in blood, human serum albumin, is also found to be glycated which has a much shorter half life and gives information on short term glycemic control. In addition, glycated albumins are considered as markers of diabetic complications such as nephropathy, peripheral vascular calcification and also in Alzheimer’s disease. The glycation proceeds from the interaction between aldehyde group of sugar and the free amino group of the protein, resulting in the formation of Schiff’s base, which undergoes a series of modifications leading to generation of imidazoyl derivatives of amino acids known as Amadori rearrangement products. The imidazoyl derivatives from arginine and lysine are the most prominent modifications observed in proteins in the presence of reducing sugar and these imidazoyl derivatives have an affinity towards certain transition metal ions. Based on our earlier exhaustive work on trapping the histidine peptides using transition metal ion, Cu(II linked to imino-diacetate complex, we explored Cu(II immobilized metal affinity chromatography (IMAC as a potential tool for specific detection of glycated peptides of human serum albumin. Our results clearly demonstrate that Cu(II IMAC is able to detect glycated peptides very efficiently while the non-glycated forms were not retained on the Cu (II column as confirmed by LC-MS/MS analysis. We further discuss the utility of IMAC technology to enrich the detection of AGE products in plasma. We anticipate that these studies may provide valuable information on understanding disease pathologies and the potential of AGE products as biomarkers of various diseases including neurodegenerative, renal and

  1. Effect of metal ions on the enzymatic hydrolysis of hemp seed oil by lipase Candida sp. 99-125.

    Science.gov (United States)

    Lu, Jike; Wang, Pei; Ke, Zhaodi; Liu, Xin; Kang, Qiaozhen; Hao, Limin

    2018-07-15

    In order to study the effect of metal ions on the enzymatic hydrolysis of hemp seed oil by Candida sp. 99-125, the spectroscopy, stability and hydrolytic activity of the biocatalyst were investigated in presence of Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Cu 2+ , Sn 2+ , Pb 2+ , Zn 2+ and Ba 2+ metal ions, respectively. The UV spectroscopy showed that all the metal ions enhanced the absorbance but the decrease of fluorescence intensity was observed. All the metal ions could improve the lipase thermal stability except Cu 2+ and Ba 2+ . Hydrolysis of hemp seed oil proved that Ca 2+ , Fe 3+ , Pb 2+ and Ba 2+ could significantly improve the hydrolytic rate, and metal ions could influence lipase selectivity. The study revealed that metal ions could improve lipase stability, hydrolysis activity in the hydrolytic process of hemp seed oil by Candida sp. 99-125. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

    Science.gov (United States)

    Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

    2017-08-15

    Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Adsorption of heavy metal ions on molybdenum and molybdenum trioxide from dilute aqueous solution

    International Nuclear Information System (INIS)

    Utsunomiya, Taizo; Hoshino, Yoshio; Sakabe, Ken-ichi

    1984-01-01

    The adsorption of heavy metal ions such as Co(II), Cu(II) and Pb(II) on molybdenum powder has been investigated by the batch technique as a function of soaking time, concentration of heavy metal ions and coexisting salts, pH etc. Molybdenum trioxide was also used as an adsorbent for a comparison to discuss the adsorption mechanism. The amount of these heavy metal ions adsorbed was highly pH and coexisting salts dependent. These adsorbents have features of selective adsorption for Pb(II) and large adsorption rate. The adsorption of heavy metal ions on these adsorbents proceeds independently or concurrently by following complex mechanism; (1) cation exchange reaction by hydroxyl radical on the surface of Mo and MoO 3 is predominant for most of heavy metal ions except Pb(II) [Co(II), Mn(II), Fe(III), Ni(II), Zn(II), Cd(II) and Sr(II)], (2) reduction (electron exchange reaction) to low ionic or metallic state after cation exchange reaction [Cu(II) and Ag(I) on Mo] and (3) formation of a compound [Pb(II) on both Mo and MoO 3 ]. (author)

  4. Cooperative adsorption of critical metal ions using archaeal poly-γ-glutamate.

    Science.gov (United States)

    Hakumai, Yuichi; Oike, Shota; Shibata, Yuka; Ashiuchi, Makoto

    2016-06-01

    Antimony, beryllium, chromium, cobalt (Co), gallium (Ga), germanium, indium (In), lithium, niobium, tantalum, the platinoids, the rare-earth elements (including dysprosium, Dy), and tungsten are generally regarded to be critical (rare) metals, and the ions of some of these metals are stabilized in acidic solutions. We examined the adsorption capacities of three water-soluble functional polymers, namely archaeal poly-γ-glutamate (L-PGA), polyacrylate (PAC), and polyvinyl alcohol (PVA), for six valuable metal ions (Co(2+), Ni(2+), Mn(2+), Ga(3+), In(3+), and Dy(3+)). All three polymers showed apparently little or no capacity for divalent cations, whereas L-PGA and PAC showed the potential to adsorb trivalent cations, implying the beneficial valence-dependent selectivity of anionic polyelectrolytes with multiple carboxylates for metal ions. PVA did not adsorb metal ions, indicating that the crucial role played by carboxyl groups in the adsorption of crucial metal ions cannot be replaced by hydroxyl groups under the conditions. In addition, equilibrium studies using the non-ideal competitive adsorption model indicated that the potential for L-PGA to be used for the removal (or collection) of water-soluble critical metal ions (e.g., Ga(3+), In(3+), and Dy(3+)) was far superior to that of any other industrially-versatile PAC materials.

  5. Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls.

    Science.gov (United States)

    Rao, M Madhava; Ramana, D K; Seshaiah, K; Wang, M C; Chien, S W Chang

    2009-07-30

    Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g(-1) for Pb(II), 21.2 mg g(-1) for Zn(II), 19.5 mg g(-1) for Cu(II), and 15.7 mg g(-1) for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

  6. Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls

    International Nuclear Information System (INIS)

    Rao, M. Madhava; Ramana, D.K.; Seshaiah, K.; Wang, M.C.; Chien, S.W. Chang

    2009-01-01

    Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g -1 for Pb(II), 21.2 mg g -1 for Zn(II), 19.5 mg g -1 for Cu(II), and 15.7 mg g -1 for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

  7. Biosorption of heavy metal ions from aqueous solution by red macroalgae.

    Science.gov (United States)

    Ibrahim, Wael M

    2011-09-15

    Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Decreased Sensitivity to Changes in the Concentration of Metal Ions as the Basis for the Hyperactivity of DtxR(E175K)

    Energy Technology Data Exchange (ETDEWEB)

    D’Aquino, J. Alejandro; Denninger, Andrew R.; Moulin, Aaron G.; D’Aquino, Katharine E.; Ringe, Dagmar; (Harvard-Med); (Brandeis)

    2010-01-12

    The metal-ion-activated diphtheria toxin repressor (DtxR) is responsible for the regulation of virulence and other genes in Corynebacterium diphtheriae. A single point mutation in DtxR, DtxR(E175K), causes this mutant repressor to have a hyperactive phenotype. Mice infected with Mycobacterium tuberculosis transformed with plasmids carrying this mutant gene show reduced signs of the tuberculosis infection. Corynebacterial DtxR is able to complement mycobacterial IdeR and vice versa. To date, an explanation for the hyperactivity of DtxR(E175K) has remained elusive. In an attempt to address this issue, we have solved the first crystal structure of DtxR(E175K) and characterized this mutant using circular dichroism, isothermal titration calorimetry, and other biochemical techniques. The results show that although DtxR(E175K) and the wild type have similar secondary structures, DtxR(E175K) gains additional thermostability upon activation with metal ions, which may lead to this mutant requiring a lower concentration of metal ions to reach the same levels of thermostability as the wild-type protein. The E175K mutation causes binding site 1 to retain metal ion bound at all times, which can only be removed by incubation with an ion chelator. The crystal structure of DtxR(E175K) shows an empty binding site 2 without evidence of oxidation of Cys102. The association constant for this low-affinity binding site of DtxR(E175K) obtained from calorimetric titration with Ni(II) is K{sub a} = 7.6 {+-} 0.5 x 10{sup 4}, which is very similar to the reported value for the wild-type repressor, K{sub a} = 6.3 x 10{sup 4}. Both the wild type and DtxR(E175K) require the same amount of metal ion to produce a shift in the electrophoretic mobility shift assay, but unlike the wild type, DtxR(E175K) binding to its cognate DNA [tox promoter-operator (toxPO)] does not require metal-ion supplementation in the running buffer. In the timescale of these experiments, the Mn(II)-DtxR(E175K)-toxPO complex

  9. Adsorption of Cd(II) Metal Ion on Adsorbent beads from Biomass Saccharomycess cereviceae - Chitosan

    Science.gov (United States)

    Hasri; Mudasir

    2018-01-01

    The adsorbent beads that was preparation from Saccharomycess cereviceae culture strain FN CC 3012 and shrimp shells waste and its application for adsorption of Cd (II) metal ion has been studied. The study start with combination of Saccharomycess cereviceae biomass to chitosan (Sc-Chi), contact time, pH of solution and initial concentration of cations. Total Cd(II) metal ion adsorbed was calculated from the difference of metal ion concentration before and after adsorption by AAS. The results showed that optimum condition for adsorption of Cd(II) ions by Sc-Chi beads was achieved with solution pH of 4, contact time of 60 minutes and initial concentration adsorption 100mg/L. The hydroxyl (-OH) and amino (-NH2) functional groups were believed to be responsible for the adsorption of Cd(II) ions.

  10. Separation of some metal ions using coupled transport supported liquid membranes

    International Nuclear Information System (INIS)

    Chaudhary, M.A.

    1993-01-01

    Liquid membrane extraction processes has become very popular due to their superiority in many ways over other separation techniques. In coupled transport membranes the metal ions can be transported across the membrane against their concentration gradient under the influence of chemical potential difference. Liquid membranes consisting of a carrier-cum-diluent, supported in microporous polymeric hydrophobic films have been studied for transport of metal ions like U(VI), Cr(VI), Be(II), V(V), Ti(IV), Zn(II), Cd(II), Hf(IV), W(VI), and Co(II). The present paper presents basic data with respect to flux and permeabilities of these metal ions across membranes based on experimental results and theoretical equations, using different carriers and diluents and provides a brief reference to possibility of such membranes for large scale applications. (author)

  11. Uptake of metal ions by a silica-based tetraphenylporphyrin sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Pyrzynska, K.; Sadowska, M.; Trojanowicz, M.

    1999-09-01

    The [5-p-carboxyphenyl-10,15,20-triphenyl]porphyrin (TPP) covalently attached to aminopropyl silica gel was examined with respect to the sorption of transition metal ions. The distribution coefficients (K{sub d}) are reported for some metal ions with this new sorbent as a function of pH. It was found that in optimum pH conditions the sorption of Cu(II) and Fe(III) is much faster than that of Co(II) and Cr(III). The binding of metal ions is strongly affected by the presence of various species accelerating the complex formation. The application of porphyrin ligands for preconcentration and metal-matrix separation was also examined using complex formation in solution coupled with an anion exchange resin and column chelation procedure, e.g. sorption of metal on an anion exchanger previously loaded with tetra(4-carboxyphenyl)porphyrin.

  12. Effect of metal ions on de novo aggregation of full-length prion protein

    International Nuclear Information System (INIS)

    Giese, Armin; Levin, Johannes; Bertsch, Uwe; Kretzschmar, Hans

    2004-01-01

    It is well established that the prion protein (PrP) contains metal ion binding sites with specificity for copper. Changes in copper levels have been suggested to influence incubation time in experimental prion disease. Therefore, we studied the effect of heavy metal ions (Cu 2+ , Mn 2+ , Ni 2+ , Co 2+ , and Zn 2+ ) in vitro in a model system that utilizes changes in the concentration of SDS to induce structural conversion and aggregation of recombinant PrP. To quantify and characterize PrP aggregates, we used fluorescently labelled PrP and cross-correlation analysis as well as scanning for intensely fluorescent targets in a confocal single molecule detection system. We found a specific strong pro-aggregatory effect of Mn 2+ at low micromolar concentrations that could be blocked by nanomolar concentration of Cu 2+ . These findings suggest that metal ions such as copper and manganese may also affect PrP conversion in vivo

  13. Bio-functionalized silver nanoparticles for selective colorimetric sensing of toxic metal ions and antimicrobial studies

    Science.gov (United States)

    Vinod Kumar, V.; Anbarasan, S.; Christena, Lawrence Rene; SaiSubramanian, Nagarajan; Philip Anthony, Savarimuthu

    2014-08-01

    Hibiscus Sabdariffa (Gongura) plant extracts (leaves (HL) and stem (HS) were used for the first time in the green synthesis of bio-functionalized silver nanoparticles (AgNPs). The bio-functionality of AgNPs has been successfully utilized for selective colorimetric sensing of potentially health and environmentally hazardous Hg2+, Cd2+ and Pb2+ metal ions at ppm level in aqueous solution. Importantly, clearly distinguishable colour for all three metal ions was observed. The influence of extract preparation condition and pH were also explored on the formation of AgNPs. Both selectivity and sensitivity differed for AgNPs synthesized from different parts of the plant. Direct correlation between the stability of green synthesized AgNPs at different pH and its antibacterial effects has been established. The selective colorimetric sensing of toxic metal ions and antimicrobial effect of green synthesized AgNPs demonstrated the multifunctional applications of green nanotechnology.

  14. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng; Wang, Yong; Lee, On On; Tian, Renmao; Cao, Huiluo; Gao, Zhaoming; Li, Yongxin; Yu, Li; Xu, Ying; Qian, Pei-Yuan

    2013-01-01

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  15. Metal-ion catalyzed polymerization in the eutectic phase in water-ice

    DEFF Research Database (Denmark)

    Monnard, Pierre-Alain; Szostak, Jack W.

    2008-01-01

    The emergence of an RNA world requires among other processes the non-enzymatic, template-directed replication of genetic polymers such as RNA or related nucleic acids, possibly catalyzed by metal ions. The absence of uridilate derivative polymerization on adenine containing templates has been...... the main issue preventing an efficient template-directed RNA polymerization. We report here the investigation of template-directed RNA polymerization in the eutectic phase in water-ice. In particular, it was found that activated Uridilate monomers in the presence of metal-ion catalysts could efficiently......-pairing opportunities. These results suggest that a template-directed RNA polymerization catalyzed by metal-ions could be carried out under eutectic phase in water-ice conditions....

  16. Alzheimer’s disease: How metal ions define β-amyloid function

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2017-01-01

    focuses on the essential coordination chemistry and biochemistry that relate transition metal ions iron, copper, and zinc to β-amyloid (Aβ) and most likely define the peptide's roles in neurons. The metal-Aβ interactions have elements of both gain of toxic function, as usually considered, but also loss......Alzheimer’s disease is increasingly recognized to be linked to the function and status of metal ions, and recently, the amyloid hypothesis has been strongly intertwined with the metal ion hypothesis; in fact, these two hypotheses fit well together and are not mutually contradictory. This review...... of natural functions, as emphasized in this review. Both these aspects and their relationships are discussed and their implications for future therapeutic strategies are outlined....

  17. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng

    2013-11-11

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  18. Angular and mass resolved energy distribution measurements with a gallium liquid metal ion source

    International Nuclear Information System (INIS)

    Marriott, Philip

    1987-06-01

    Ionisation and energy broadening mechanisms relevant to liquid metal ion sources are discussed. A review of experimental results giving a picture of source operation and a discussion of the emission mechanisms thought to occur for the ionic species and droplets emitted is presented. Further work is suggested by this review and an analysis system for angular and mass resolved energy distribution measurements of liquid metal ion source beams has been constructed. The energy analyser has been calibrated and a series of measurements, both on and off the beam axis, of 69 Ga + , Ga ++ and Ga 2 + ions emitted at various currents from a gallium source has been performed. A comparison is made between these results and published work where possible, and the results are discussed with the aim of determining the emission and energy spread mechanisms operating in the gallium liquid metal ion source. (author)

  19. Electrochemical membrane reactor: In situ separation and recovery of chromic acid and metal ions

    International Nuclear Information System (INIS)

    Khan, Jeeshan; Tripathi, Bijay P.; Saxena, Arunima; Shahi, Vinod K.

    2007-01-01

    An electrochemical membrane reactor with three compartments (anolyte, catholyte and central compartment) based on in-house-prepared cation- and anion-exchange membrane was developed to achieve in situ separation and recovery of chromic acid and metal ions. The physicochemical and electrochemical properties of the ion-exchange membrane under standard operating conditions reveal its suitability for the proposed reactor. Experiments using synthetic solutions of chromate and dichromate of different concentrations were carried out to study the feasibility of the process. Electrochemical reactions occurring at the cathode and anode under operating conditions are proposed. It was observed that metal ion migrated through the cation-exchange membrane from central compartment to catholyte and OH - formation at the cathode leads to the formation of metal hydroxide. Simultaneously, chromate ion migrated through the anion-exchange membrane from central compartment to the anolyte and formed chromic acid by combining H + produced their by oxidative water splitting. Thus a continuous decay in the concentration of chromate and metal ion was observed in the central compartment, which was recovered separately in the anolyte and catholyte, respectively, from their mixed solution. This process was completely optimized in terms of operating conditions such as initial concentration of chromate and metal ions in the central compartment, the applied cell voltage, chromate and metal ion flux, recovery percentage, energy consumption, and current efficiency. It was concluded that chromic acid and metal ions can be recovered efficiently from their mixed solution leaving behind the uncharged organics and can be reused as their corresponding acid and base apart from the purifying water for further applications

  20. Studies on regularities of metal ion sorption from seawater by clinoptilolytes of different origin

    International Nuclear Information System (INIS)

    Khamizov, R.Kh.; Butenko, T.Yu.; Bronov, L.V.; Skovyra, V.V.; Novikova, V.A.; AN SSSR, Vladivostok

    1988-01-01

    The regularities of metal ion sorption from sea water by different clinoptilolyte (CP) samples are studied with the purpose of choosing the most prospective sorbents to extract strontium and rubidium. It is shown that the internal diffusion is the sorption rate determining stage. The dependence of effective coefficients of internal diffusion on the exchange level is determined. The distribution coefficients and those of single metal ion separation are determined, the series of sorption selectivity are determined. All CP studied can be used for initial Rb concentration from sea water, and to extract strontium it is advisable to use zeolites of Dzegvi and Tedzami deposits

  1. Highly sensitive heavy metal ion detection using AlQ3 microwire functionalized QCM

    Science.gov (United States)

    Can, Nursel; Aǧar, Meltem; Altındal, Ahmet

    2016-03-01

    Tris(8-hydroxyquinoline) aluminum (Alq3) microwires was successfully synthesized for the fabrication of Alq3 microwires-coated QCM sensors to detect the heavy metal ions in aqueous solution. AT-cut quartz crystal microbalance (QCM) of 10 MHz fundamental resonance frequency having gold electrodes were used as transducers. Typical measuring cycle consisted of repeated flow of target measurands through the flow cell and subsequent washing to return the baseline. The QCM results indicated that the Alq3 microwires exhibit excellent sensitivity, stability and short response-recovery time, which are much attractive for the development of portable and highly sensitive heavy metal ion sensors in water samples.

  2. Nanodiamonds act as Trojan horse for intracellular delivery of metal ions to trigger cytotoxicity.

    Science.gov (United States)

    Zhu, Ying; Zhang, Yu; Shi, Guosheng; Yang, Jinrong; Zhang, Jichao; Li, Wenxin; Li, Aiguo; Tai, Renzhong; Fang, Haiping; Fan, Chunhai; Huang, Qing

    2015-02-05

    Nanomaterials hold great promise for applications in the delivery of various molecules with poor cell penetration, yet its potential for delivery of metal ions is rarely considered. Particularly, there is limited insight about the cytotoxicity triggered by nanoparticle-ion interactions. Oxidative stress is one of the major toxicological mechanisms for nanomaterials, and we propose that it may also contribute to nanoparticle-ion complexes induced cytotoxicity. To explore the potential of nanodiamonds (NDs) as vehicles for metal ion delivery, we used a broad range of experimental techniques that aimed at getting a comprehensive assessment of cell responses after exposure of NDs, metal ions, or ND-ion mixture: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Trypan blue exclusion text, optical microscope observation, synchrotron-based scanning transmission X-ray microscopy (STXM) and micro X-ray fluorescence (μXRF) microscopy, inductively coupled plasma-mass spectrometry (ICP-MS), reactive oxygen species (ROS) assay and transmission electron microscopy (TEM) observation. In addition, theoretical calculation and molecular dynamics (MD) computation were used to illustrate the adsorption properties of different metal ion on NDs as well as release profile of ion from ND-ion complexes at different pH values. The adsorption capacity of NDs for different metal ions was different, and the adsorption for Cu2+ was the most strong among divalent metal ions. These different ND-ion complexes then had different cytotoxicity by influencing the subsequent cellular responses. Detailed investigation of ND-Cu2+ interaction showed that the amount of released Cu2+ from ND-Cu2+ complexes at acidic lysosomal conditions was much higher than that at neutral conditions, leading to the elevation of intracellular ROS level, which triggered cytotoxicity. By theoretical approaches, we demonstrated that the functional carbon surface and cluster structures of NDs made them

  3. Interaction of Cr (III), Ni (II), Pb (II) with DTPA complexes of essential metal ions

    International Nuclear Information System (INIS)

    Gulzar, S.; Zahida; Maqsood, T.; Naqvi, R.R.

    2002-01-01

    With the increase of anthropogenic activities in the environment, heavy metal toxicity (Chromium, Nickel and Lead) is more common now. DTPA (diethylene triamine pentaacetic acid) a polyamino carboxylic acid is widely used to form hydrophilic and stable complexes with most of the metal ions. In this spectrophotometric study, concentration of Cr(III), Ni(II) and Pb(II) (toxic metal ions) exchanged with Fe(III), Zn(II) and Ca(II) from their DTPA complexes were estimated at pH 4,7 and 9. Concentration of added metal was varied from 1-4 times to that of complexed metal. (author)

  4. Effects of site substitution and metal ion addition on doped manganites

    CERN Document Server

    Pradhan, A K; Roul, B K; Sahu, D R; Muralidhar, M

    2002-01-01

    We report transport, magnetization and transmission electron microscopy studies of the effects of A-and B-site substitution, and the addition of metal ions such as Pt, Ag and Sr, on doped ABO sub 3 perovskites, where A = La, Pr etc and B = Mn. Disorder induced by such substitution changes the behaviour of the charge-ordered (CO) state significantly. A-and B-site substitution suppresses the CO phase due to size mismatch and disorder produced by inhomogeneity. On the other hand, addition of metal ions such as Pt and Ag improves several colossal-magnetoresistance properties significantly due to microstructural effects and enhanced current percolation through grain boundaries.

  5. Metal ion transport quantified by ICP-MS in intact cells

    Science.gov (United States)

    Figueroa, Julio A. Landero; Stiner, Cory A.; Radzyukevich, Tatiana L.; Heiny, Judith A.

    2016-01-01

    The use of ICP-MS to measure metal ion content in biological tissues offers a highly sensitive means to study metal-dependent physiological processes. Here we describe the application of ICP-MS to measure membrane transport of Rb and K ions by the Na,K-ATPase in mouse skeletal muscles and human red blood cells. The ICP-MS method provides greater precision and statistical power than possible with conventional tracer flux methods. The method is widely applicable to studies of other metal ion transporters and metal-dependent processes in a range of cell types and conditions. PMID:26838181

  6. Providing affinity

    DEFF Research Database (Denmark)

    Guglielmi, Michel; Johannesen, Hl

    2004-01-01

    , Essex, Hertfordshire, Norfolk and Suffolk. Research found that there was a lack of identity or sense of belonging and nothing anchoring people to the region as a whole. Common affinity is somehow forced to the people of East England and thereby we came to the conclusion that a single landmark...... and potential situations but also virtual events that calls for an undeterminated process of resolution. This process is activated by the user who co-produces the actualisation as an answer to a virtual reality that we defined at the first place. The potential situations or the possible it is a fantomatic real....... The possible is like the real. It is determinated and it only lakes existence. While the possible is already made, the virtual is like a problematic which needs to be resolved and actualized. Our installations are based on high tech interactivity where we use sensors and remote communication to offer a sense...

  7. Separation of metal ions using an o-hydroxypropiophenoxime resin

    International Nuclear Information System (INIS)

    King, J.N.

    1977-12-01

    A chelating ion-exchange resin incorporating an o-hydroxypropiophenoxime functional group onto an XAD-4 polymer matrix has been synthesized. This resin has been used for the separation and quantitative determination of both copper and molybdenum by high-speed liquid chromatography. Iron, uranium, citrate, and fluoride were found to interfere in the determination of copper. Of the ions tested, none were found to interfere with the determination of molybdenum. Several NBS Standard samples were successfully analyzed for copper and molybdenum. The new method is both accurate and fast. Most samples can be analyzed in less than ten minutes. Bis(2-hydroxyethyl) dithiocarbamate was shown to be superior to PAR as a color-forming reagent for the continuous spectrophotometric detection of copper. Thiolactic acid was shown to be adaptable to the continuous spectrophotometric detection of molybdenum. Both dyes gave linear responses when peak height was plotted against micrograms of metal

  8. Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis

    International Nuclear Information System (INIS)

    Khozhaenko, Elena; Kovalev, Valeri; Podkorytova, Elena; Khotimchenko, Maksim

    2016-01-01

    Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems. - Highlights: • Low molecular nanoscaled pectin was obtained using original hydrolysis method • Metal binding activity of pectin compounds was studied in a batch sorption system • Pectins exert highest metal binding activity at pH 6.0 • Metal binding isotherms of all pectins are best described by the Langmuir equation • Low molecular pectin from seagrasses is more effective than high-molecular pectins

  9. Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis

    Energy Technology Data Exchange (ETDEWEB)

    Khozhaenko, Elena [Far Eastern Federal University, School of Biomedicine, 8, Sukhanova str., Vladivostok 690091 (Russian Federation); A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation); Kovalev, Valeri; Podkorytova, Elena [A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation); Khotimchenko, Maksim, E-mail: maxkhot@yandex.ru [Far Eastern Federal University, School of Biomedicine, 8, Sukhanova str., Vladivostok 690091 (Russian Federation); A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation)

    2016-09-15

    Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems. - Highlights: • Low molecular nanoscaled pectin was obtained using original hydrolysis method • Metal binding activity of pectin compounds was studied in a batch sorption system • Pectins exert highest metal binding activity at pH 6.0 • Metal binding isotherms of all pectins are best described by the Langmuir equation • Low molecular pectin from seagrasses is more effective than high-molecular pectins.

  10. Metal ion induced room temperature phase transformation and stimulated infrared spectroscopy on TiO{sub 2}-based surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gole, James L. [Schools of Physics and Mechanical Engineering, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332-0430 (United States)], E-mail: jim.gole@physics.gatech.edu; Prokes, S.M. [Code 6876, NRL, Washington, DC 20375 (United States)], E-mail: prokes@estd.nrl.navy.mil; White, Mark G. [Dave C. Swalm School of Chemical Engineering, James Worth Bagley College of Engineering, Box 959, MS 39762 (United States)], E-mail: white@che.msstate.edu

    2008-11-30

    Raman and infrared spectroscopy are used to demonstrate (1) the high spin metal ion induced room temperature transformation of anatase to rutile TiO{sub 2} and (2) the phenomena of stimulated IR spectroscopy induced by simultaneous nitrogen doping and high spin metal ion seeding of a TiO{sub 2} nanocolloid lattice.

  11. Metal ion induced room temperature phase transformation and stimulated infrared spectroscopy on TiO2-based surfaces

    International Nuclear Information System (INIS)

    Gole, James L.; Prokes, S.M.; White, Mark G.

    2008-01-01

    Raman and infrared spectroscopy are used to demonstrate (1) the high spin metal ion induced room temperature transformation of anatase to rutile TiO 2 and (2) the phenomena of stimulated IR spectroscopy induced by simultaneous nitrogen doping and high spin metal ion seeding of a TiO 2 nanocolloid lattice

  12. The Gellyfish: an in-situ equilibrium-based sampler for determining multiple free metal ion concentrations in marine ecosystems

    Science.gov (United States)

    Free metal ions are usually the most bioavailable and toxic metal species to aquatic organisms, but they are difficult to measure because of their extremely low concentrations in the marine environment. Many of the current methods for determining free metal ions are complicated a...

  13. Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water.

    Science.gov (United States)

    Rajfur, Małgorzata; Kłos, Andrzej; Wacławek, Maria

    2010-11-01

    Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions--Mn(2+), Cu(2+), Zn(2+) and Cd(2+)--were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30 min, with 90-95% of metal ions sorbed in first 10 min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30 min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Divalent metal ion removal from aqueous solution by acid-treated ...

    African Journals Online (AJOL)

    ions determined from the Langmuir isotherm showed that C. indica had the largest sorption capacity for Pb2+ ions and the least sorption for Ni2+. The results also showed that garlic-treatment of C. indica biomass enhanced its sorption capacity for the divalent metal ions, with the enhancement factor varying from 1.22 to 1.44 ...

  15. Conversion of agonist site to metal-ion chelator site in the beta(2)-adrenergic receptor

    DEFF Research Database (Denmark)

    Elling, C E; Thirstrup, K; Holst, Birgitte

    1999-01-01

    Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor,...... as generic, pharmacologic tools to switch 7TM receptors with engineered metal-ion sites on or off at will.......Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor......, in this paper we construct an activating metal-ion site between the amine-binding Asp-113 in TM-III-or a His residue introduced at this position-and a Cys residue substituted for Asn-312 in TM-VII. No increase in constitutive activity was observed in the mutant receptors. Signal transduction was activated...

  16. Specificity of the metalloregulator CueR for monovalent metal ions

    DEFF Research Database (Denmark)

    Szunyogh, Dániel; Szokolai, Hajnalka; Thulstrup, Peter Waaben

    2015-01-01

    (II) , and Hg(II) binding to model systems encompassing the metal-ion-binding loop of CueR from E. coli and V. cholerae. In the presence of Ag(I) , a conserved cysteine residue displays a pKa value for deprotonation of the thiol that is close to the physiological pH value. This property is only observed...

  17. Predicting the stability constants of metal-ion complexes from first principles

    Czech Academy of Sciences Publication Activity Database

    Gutten, Ondrej; Rulíšek, Lubomír

    2013-01-01

    Roč. 52, č. 18 (2013), s. 10347-10355 ISSN 0020-1669 Institutional support: RVO:61388963 Keywords : stability constants * solvation energy * metal-ion complexation * theoretical calculations * DFT methods Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.794, year: 2013

  18. Impact of metal-ion contaminated silica particles on gate oxide integrity

    NARCIS (Netherlands)

    Rink, Ingrid; Wali, F.; Knotter, D.M.

    2009-01-01

    The impact of metal-ion contamination (present on wafer surface before oxidation) on gate oxide integrity (GOI) is well known in literature, which is not the case for clean silica particles [1, 2]. However, it is known that particles present in ultra-pure water (UPW) decrease the random yield in

  19. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    KAUST Repository

    Kaur, Sukhmanpreet

    2017-07-04

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4 ± 0.05, 7 ± 0.05 and 9 ± 0.05) and three different temperatures (15 ± 0.5°C, 30 ± 0.5°C and 45 ± 0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  20. Transition metal ions mediated tyrosine based short peptide amphiphile nanostructures inhibit bacterial growth.

    Science.gov (United States)

    Joshi, Khashti Ballabh; Singh, Ramesh; Mishra, Narendra Kumar; Kumar, Vikas; Vinayak, Vandana

    2018-05-17

    We report the design and synthesis of biocompatible small peptide based molecule for the controlled and targeted delivery of the encapsulated bioactive metal ions via transforming their internal nanostructures. Tyrosine based short peptide amphiphile (sPA) was synthesized which self-assembled into β-sheet like secondary structures. The self assembly of the designed sPA was modulated by using different bioactive transition metal ions which is confirmed by spectroscopic and microscopic techniques. These bioactive metal ions conjugated sPA hybrid structures are further used to develop antibacterial materials. It is due to the excellent antibacterial activity of zinc ions that the growth of clinically relevant bacteria such as E. Coli was inhibited in the presence of zinc-sPA conjugate. The bacterial test demonstrated that owing to high biocompatibility with bacterial cell, the designed sPA worked as metal ions delivery agent and therefore it can show great potential in locally addressing bacterial infections. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

    International Nuclear Information System (INIS)

    Burke, Aoife M.; Hanrahan, John P.; Healy, David A.; Sodeau, John R.; Holmes, Justin D.; Morris, Michael A.

    2009-01-01

    Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 μmol g -1 for Cr, 340 μmol g -1 for Ni, 358 μmol g -1 for Fe, 364 μmol g -1 for Mn and 188 μmol g -1 for Pd

  2. Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Aoife M.; Hanrahan, John P. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Healy, David A.; Sodeau, John R. [Department of Chemistry, Centre of Research in Atmospheric Chemistry, University College Cork, Cork (Ireland); Holmes, Justin D. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Morris, Michael A. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)], E-mail: m.morris@ucc.ie

    2009-05-15

    Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 {mu}mol g{sup -1} for Cr, 340 {mu}mol g{sup -1} for Ni, 358 {mu}mol g{sup -1} for Fe, 364 {mu}mol g{sup -1} for Mn and 188 {mu}mol g{sup -1} for Pd.

  3. Release of metal ions from fixed orthodontic appliance: an in vitro study in continuous flow system.

    Science.gov (United States)

    Mikulewicz, Marcin; Chojnacka, Katarzyna; Wołowiec, Paulina

    2014-01-01

    To evaluate the release of metal ions from fixed orthodontic appliances. A new system for in vitro testing of dental materials was constructed and consisted of a thermostatic glass reactor that enabled immersion of the studied material. Experimental conditions reflected the human oral cavity, with a temperature of 37°C and a saliva flow rate of 0.5mL/min. The simulated fixed orthodontic appliance made of stainless steel was evaluated. Sampling was performed at several time points during the 28-day study, and the metal ion concentration was determined by inductively coupled plasma optical emission spectrometry. The total mass of released metal ions from the appliance during 4 weeks of the experiment was as follows nickel 18.7 μg, chromium 5.47 μg, copper 31.3 μg. The estimated doses of nickel, chromium, and copper determined by extrapolation of experimental data released during the treatment period were far below the toxic dose to humans. This shows that orthodontic treatment might not be a significant source of exposure to these metal ions.

  4. Selective Decontamination Effect of Metal Ions in Soil Using Supercritical CO2 and TBP Complex

    International Nuclear Information System (INIS)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung

    2014-01-01

    Decontamination of soil pollution is difficult because the type of contamination largely depends on the characteristics of the pollutant and the area. Also, existing soil decontamination methods generate large quantities of secondary waste and additional process costs. For this reason, new decontamination methods are always under active investigation. A method involving the use of supercritical carbon dioxide with excellent permeability in place of chemical solvents is currently being studied. Unlike other heavy metals in fission products, uranium is used as fuel, and must be handled carefully. Therefore, in this paper, we studied a supercritical carbon dioxide method for decontaminating heavy metal ions in soil using tri-n-butyl phosphate(TBP), which is well known as a ligand for the extraction of metal ions of actinium. We investigated the decontamination effect of heavy metal ions in the soil using TBP-HNO 3 Complex and supercritical carbon dioxide. The study results showed that when heavy metals in soil are extracted using supercritical carbon dioxide, the extraction efficiency is different according to the type of pollutant metal ions in the soil. When TBP-HNO 3 Complex is used with an extractant, uranium extraction is very effective, but lithium, strontium, and cesium extraction is not effective. Therefore, in the case of a mixture of uranium and other metals such as lithium, strontium, cesium, and so on in soil contaminated by fission product leaks from nuclear power plants, we can selectively decontaminate uranium with supercritical carbon dioxide and TBP-HNO 3 Complex

  5. Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

    Science.gov (United States)

    Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

    2015-10-01

    Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

  6. The effect of hydrogen peroxide concentration on metal ion release from dental casting alloys.

    Science.gov (United States)

    Al-Salehi, S K; Hatton, P V; Johnson, A; Cox, A G; McLeod, C

    2008-04-01

    There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a typical porcelain-firing cycle. Discs (n = 7) of each alloy were immersed in either 0%, 3%, 10% or 30% (w/v) HP solutions for 24 h at 37 degrees C. Samples were taken for metal ion release determination using inductively coupled plasma-mass spectrometry and the data analysed using a two-way anova followed by a one-way anova. The surface roughness of each disc was measured using a Talysurf contact profilometer before and after bleaching and the data analysed using a paired t-test. With the exception of gold, the differences in metal ion concentration after treatment with 0% (control) and each of 3%, 10% and 30% HP (w/v) were statistically significant (P alloys increased with increasing HP concentrations (over 3000% increase in Ni and 1400% increase in Pd ions were recorded when HP concentration increased from 0% to 30%). Surface roughness values of the samples before and after bleaching were not significantly different (P > 0.05) Exposure of the two dental casting alloys to HP solutions increased metal ion release of all the elements except gold.

  7. MCTBI: a web server for predicting metal ion effects in RNA structures.

    Science.gov (United States)

    Sun, Li-Zhen; Zhang, Jing-Xiang; Chen, Shi-Jie

    2017-08-01

    Metal ions play critical roles in RNA structure and function. However, web servers and software packages for predicting ion effects in RNA structures are notably scarce. Furthermore, the existing web servers and software packages mainly neglect ion correlation and fluctuation effects, which are potentially important for RNAs. We here report a new web server, the MCTBI server (http://rna.physics.missouri.edu/MCTBI), for the prediction of ion effects for RNA structures. This server is based on the recently developed MCTBI, a model that can account for ion correlation and fluctuation effects for nucleic acid structures and can provide improved predictions for the effects of metal ions, especially for multivalent ions such as Mg 2+ effects, as shown by extensive theory-experiment test results. The MCTBI web server predicts metal ion binding fractions, the most probable bound ion distribution, the electrostatic free energy of the system, and the free energy components. The results provide mechanistic insights into the role of metal ions in RNA structure formation and folding stability, which is important for understanding RNA functions and the rational design of RNA structures. © 2017 Sun et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  8. Electrospray droplet exposure to organic vapors: metal ion removal from proteins and protein complexes.

    Science.gov (United States)

    DeMuth, J Corinne; McLuckey, Scott A

    2015-01-20

    The exposure of aqueous nanoelectrospray droplets to various organic vapors can dramatically reduce sodium adduction on protein ions in positive ion mass spectra. Volatile alcohols, such as methanol, ethanol, and isopropanol lead to a significant reduction in sodium ion adduction but are not as effective as acetonitrile, acetone, and ethyl acetate. Organic vapor exposure in the negative ion mode, on the other hand, has essentially no effect on alkali ion adduction. Evidence is presented to suggest that the mechanism by which organic vapor exposure reduces alkali ion adduction in the positive mode involves the depletion of alkali metal ions via ion evaporation of metal ions solvated with organic molecules. The early generation of metal/organic cluster ions during the droplet desolvation process results in fewer metal ions available to condense on the protein ions formed via the charged residue mechanism. These effects are demonstrated with holomyoglobin ions to illustrate that the metal ion reduction takes place without detectable protein denaturation, which might be revealed by heme loss or an increase in charge state distribution. No evidence is observed for denaturation with exposure to any of the organic vapors evaluated in this work.

  9. Effect of metal ion concentration on the biosorption of Pb2+ and ...

    African Journals Online (AJOL)

    The influence of initial metal ion concentration of the batch sorption of Pb2+ and Cd2+ onto a low-cost biosorbent was investigated. The experimental results were analysed in terms of Langmuir and Freundlich isotherms. According to the evaluation using Langmuir equation, the monolayer sorption capacity obtained were ...

  10. FTIR spectroscopy structural analysis of the interaction between Lactobacillus kefir S-layers and metal ions

    Science.gov (United States)

    Gerbino, E.; Mobili, P.; Tymczyszyn, E.; Fausto, R.; Gómez-Zavaglia, A.

    2011-02-01

    FTIR spectroscopy was used to structurally characterize the interaction of S-layer proteins extracted from two strains of Lactobacillus kefir (the aggregating CIDCA 8348 and the non-aggregating JCM 5818) with metal ions (Cd +2, Zn +2, Pb +2 and Ni +2). The infrared spectra indicate that the metal/protein interaction occurs mainly through the carboxylate groups of the side chains of Asp and Glut residues, with some contribution of the NH groups belonging to the peptide backbone. The frequency separation between the νCOO - anti-symmetric and symmetric stretching vibrations in the spectra of the S-layers in presence of the metal ions was found to be ca. 190 cm -1 for S-layer CIDCA 8348 and ca. 170 cm -1 for JCM 5818, denoting an unidentate coordination in both cases. Changes in the secondary structures of the S-layers induced by the interaction with the metal ions were also noticed: a general trend to increase the amount of β-sheet structures and to reduce the amount of α-helices was observed. These changes allow the proteins to adjust their structure to the presence of the metal ions at minimum energy expense, and accordingly, these adjustments were found to be more important for the bigger ions.

  11. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    Science.gov (United States)

    Kaur, Sukhmanpreet; Kumar, Vijay; Chawla, Mohit; Cavallo, Luigi; Poater, Albert; Upadhyay, Niraj

    2017-07-01

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4±0.05, 7±0.05 and 9±0.05) and three different temperatures (15±0.5°C, 30±0.5°C and 45±0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  12. The removal of heavy metal ions from aqueous solutions using sour ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... quacy of our conventional methods of river dumping was further exposed by ... essential in order to make a positive impact on our environmental hygiene. The discharge of metallic ions in industrial effluent is of great concern ...

  13. Metal-ion complexes of functionalised 1,10-Phenanthrolines as hydrolytic synzymes

    NARCIS (Netherlands)

    Weijnen, J.G.J.

    1993-01-01

    In this thesis metal-ion complexes of functionalised 1,10-phenanthroline derivatives have been studied as model systems for hydrolytic metallo-enzymes. Amphiphilic metallo- complexes incorporated into micelles or vesicles and water-soluble complexes in pure aqueous buffer solutions, have

  14. Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

    International Nuclear Information System (INIS)

    Giraudi, G.; Baggiani, C.; Giovannoli, C.; Marletto, C.; Vanni, A.

    1999-01-01

    A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. Preparation and characterization of gum karaya hydrogel nanocomposite flocculant for metal ions removal from mine effluents

    CSIR Research Space (South Africa)

    Fosso-Kankeu, E

    2016-02-01

    Full Text Available This research paper reports the removal of heavy metal ions from mine effluents using the gum karaya (GK)-grafted poly(acrylamide-co-acrylic acid) incorporated iron oxide magnetic nanoparticles (Fe3O4 MNPs) hydrogel nanocomposite [i.e., GK...

  16. Effects of metal ions on biomass and 5-aminolevulinic acid production in Rhodopseudomonas palustris wastewater treatment.

    Science.gov (United States)

    Liu, Shuli; Zhang, Guangming; Li, Jianzheng; Li, Xiangkun; Zhang, Jie

    2016-01-01

    This work investigated the effects of eight metal ions on Rhodopseudomonas palustris growth and 5-aminolevulinic acid (ALA) yield in wastewater treatment. Results show that metal ions (Mg(2+) of 15 mmol/L, Fe(2+) of 400 μmol/L, Co(2+) of 4 μmol/L, Ni(2+) of 8 μmol/L and Zn(2+) of 4 μmol/L) could effectively improve the chemical oxygen demand (COD) removal, Rp. palustris biomass and ALA yield. The highest ALA yield of 13.1 mg/g-biomass was achieved with Fe(2+) of 400 μmol/L. ALA yields were differentially increased under different metal ions in the following order: Fe(2+) group > Mg(2+) group > Co(2+) group = Ni(2+) group > Zn(2+) group = Mo(2+) group > control. Cu(2+) and Mn(2+) inhibited Rp. palustris growth and ALA production. Mechanism analysis revealed that metal ions changed ALA yields by influencing the activities of ALA synthetase and ALA dehydratase.

  17. Preparation and adsorption behavior for metal ions and humic acid of chitosan derivatives crosslinked by irradiation

    International Nuclear Information System (INIS)

    Zhao Long; Wasikiewicz, J.M.; Mitomo, H.; Nagasawa, N.; Yoshii, F.

    2007-01-01

    This article deals with the determination of the adsorption properties of metal ions and humic acid in wa- ter on crosslinked chitosan derivatives (carboxymethylchitosan) which were formed using the irradiation technique without any additives. The solubility test of these crosslinked materials were investigated in acidic, alkaline media, distilled water, and certain organic solvents. Scanning electron microscopic (SEM) images showed that the crosslinked chitosan derivatives possessed a porous morphological structure. Charged characteristic analyses demonstrated typically pH-dependent properties of the crosslinked materials. The adsorption studies were carded out by the batch method at room temperature. Adsorption of heavy metal ions (such as Cu 2+ , Cd 2+ ) and humic acid onto crosslinked samples was found to be strongly pH-dependent. Adsorption kinetic studies indicated the rapid removal of metal ions, and humic acid from the aqueous solutions. Moreover, isothermal adsorption data revealed that Cu 2+ , Cd 2+ , and humic acid were removed by these crosslinked materials with high efficiency. Adsorption isothermal data were interpreted well by the Langmuir equation. These crosslinked carboxymethylated chitosan derivatives indicate favorable adsorption of metal ions and humic acid. (authors)

  18. Animal experimental investigations of the problem of the decorporation of radioactive metal ions

    International Nuclear Information System (INIS)

    Berner, W.

    1973-01-01

    Basically, it is possible to reduce the radiation exposure by excretion intensification of incorporated radioactive materials. Chelate agents have proved to be particularly effective for the accelerated elimination of radioactive metal ions. The kinetics of the distribution and excretion of 57 CoCl 2 , 65 ZnCl 2 and 203 HgCl 2 on the rat under the influence of the chelating agent penicillamin (D-ββ-dimethylcystein) was investigated and the reduction of the radiation exposure in man was calculated from the animal-experimentally gained data. At various times after the incorporation of metal ions, the whole body radioactivity and, after killing the animals, the radioactivity of the organs liver, kidney, spleen, skeleton, muscles and blood, were measured. From the course of the measured radioactivities with time, the biokinetic data of the radioactive metal ions (effective half-lives, selection factors and their components) were determined by means of regression analyses. The chelating agent was applied at different times before or after incorporation of the radioactive metal ions. (EK/LH) [de

  19. Effect Of Metal Ions On Triphenylmethane Dye Decolorization By Laccase From Trametes Versicolor

    Directory of Open Access Journals (Sweden)

    Chmelová Daniela

    2015-12-01

    Full Text Available The aim of this study was investigate the influence of different metal ions on laccase activity and triphenylmethane dye decolorization by laccase from white-rot fungus Trametes versicolor. Laccase activity was inhibited by monovalent ions (Li+, Na+, K+ and Ag+ but the presence of divalent ions increased laccase activity at the concentration of 10 mmol/l. The effect of metal ions on decolorization of triphenylmethane dyes with different structures namely Bromochlorophenol Blue, Bromophenol Blue, Bromocresol Blue and Phenol Red was tested. The presence of metal ions (Na+, K+, Mg2+, Ca2+, Ba2+, Mn2+, Zn2+ slightly decreased triphenylmethane dye decolorization by laccase from T. versicolor except Na+ and Mg2+, which caused the increase of decolorization for all tested dyes. Decolorization of selected dyes showed that the presence of low-molecular-weight compounds is necessary for effective decolorization. Hydroxybenzotriazole (HBT is the most frequently used. Although HBT belongs to most frequently used redox mediator and generally increase decolorization efficiency, so its presence decreased decolorization percentage of Bromophenol Blue and Bromochlorophenol Blue, the influence of metal ions to dye decolorization by laccase has the similar course with or without presence of redox mediator HBT.

  20. Enhancement of autofluorescence of the brown-rot fungus Piptoporus betulinus by metal ions

    Czech Academy of Sciences Publication Activity Database

    Žižka, Zdeněk; Větrovský, Tomáš; Gabriel, Jiří

    2010-01-01

    Roč. 55, č. 6 (2010), s. 625-628 ISSN 0015-5632 R&D Projects: GA ČR GA526/07/0620; GA MŠk LC06066 Institutional research plan: CEZ:AV0Z50200510 Keywords : Piptoporus betulinus * autofluorescenc * metal ions Subject RIV: EE - Microbiology, Virology Impact factor: 0.977, year: 2010

  1. Piezoelectric sensor for sensitive determination of metal ions based on the phosphate-modified dendrimer

    Science.gov (United States)

    Wang, S. H.; Shen, C. Y.; Lin, Y. M.; Du, J. C.

    2016-08-01

    Heavy metal ions arising from human activities are retained strongly in water; therefore public water supplies must be monitored regularly to ensure the timely detection of potential problems. A phosphate-modified dendrimer film was investigated on a quartz crystal microbalance (QCM) for sensing metal ions in water at room temperature in this study. The chemical structures and sensing properties were characterized by Fourier transform infrared spectroscopy and QCM measurement, respectively. This phosphate-modified dendrimer sensor can directly detect metal ions in aqueous solutions. This novel sensor was evaluated for its capacity to sense various metal ions. The sensor exhibited a higher sensitivity level and shorter response time to copper(II) ions than other sensors. The linear detection range of the prepared QCM based on the phosphate-modified dendrimer was 0.0001 ∼ 1 μM Cu(II) ions (R2 = 0.98). The detection properties, including sensitivity, response time, selectivity, reusability, maximum adsorption capacity, and adsorption equilibrium constants, were also investigated.

  2. Metal ion site engineering indicates a global toggle switch model for seven-transmembrane receptor activation

    DEFF Research Database (Denmark)

    Elling, Christian E; Frimurer, Thomas M; Gerlach, Lars-Ole

    2006-01-01

    for monoamine binding in TM-III, was used as the starting point to engineer activating metal ion sites between the extracellular segments of the beta2-adrenergic receptor. Cu(II) and Zn(II) alone and in complex with aromatic chelators acted as potent (EC50 decreased to 0.5 microm) and efficacious agonists...

  3. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    KAUST Repository

    Kaur, Sukhmanpreet; Kumar, Vijay; Chawla, Mohit; Cavallo, Luigi; Poater, Albert; Upadhyay, Niraj

    2017-01-01

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4 ± 0.05, 7 ± 0.05 and 9 ± 0.05) and three different temperatures (15 ± 0.5°C, 30 ± 0.5°C and 45 ± 0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  4. The use of natural and industrial aluminosilicates in the process of adsorption of heavy metals ions

    OpenAIRE

    Tsvetkova, A.; Akayev, O.

    2010-01-01

    The analysis of periodic scientific publications and patent literature was made, in which the possibilities of using natural and industrial silicon-containing compounds as adsorbents of ions of heavy metals are generalized. The conditions of adsorption, as well as the numerical values of the adsorption capacity of the studied materials are described Key words: adsorption, natural and industrial aluminosilicates, heavy metals ions.

  5. Interactions between humic acid and hematite and their effects on metal ion speciation

    NARCIS (Netherlands)

    Vermeer, A.W.P.

    1996-01-01


    The impact of toxic chemicals (like metal ions) on the environment is a phenomenon that has been recognised as a mayor problem over the last decades. The speciation of these chemicals determines whether or not a contaminated site has to be regarded as dangerous. The fate of the

  6. Multiheteromacrocycles that complex metal ions. Fourth progress report, 1 May 1977--30 April 1978

    International Nuclear Information System (INIS)

    Cram, D.J.

    1978-01-01

    Results are reported in a program to design, synthesize, and evaluate polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions. Work during the reporting period was devoted to synthesis and study of cyclohexametaphenylenes and cyclic phosphine oxides

  7. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  8. Some ENDOR studies of 3d transition metal ions in semiconductors

    International Nuclear Information System (INIS)

    Engelen, P.P.J.

    1980-01-01

    The author considers 3d transition metal ions substituted in covalent semiconducting crystals. The magnitude of the contact hyperfine field at the 59 Co nucleus in cobalt doped CdS is determined. The results of an ENDOR study of supertransferred hyperfine interactions with nearest neighbour Ga ions in Mn doped GaP are presented. (G.T.H.)

  9. Asparagus cochinchinensis Extract Alleviates Metal Ion-Induced Gut Injury in Drosophila: An In Silico Analysis of Potential Active Constituents

    Directory of Open Access Journals (Sweden)

    Weiyu Zhang

    2016-01-01

    Full Text Available Metal ions and sulfate are components of atmospheric pollutants that have diverse ways of entering the human body. We used Drosophila as a model to investigate the effect of Asparagus cochinchinensis (A. cochinchinensis extracts on the gut and characterized gut homeostasis following the ingestion of metal ions (copper, zinc, and aluminum. In this study, we found that the aqueous A. cochinchinensis extract increased the survival rate, decreased epithelial cell death, and attenuated metal ion-induced gut morphological changes in flies following chronic exposure to metal ions. In addition, we screened out, by network pharmacology, six natural products (NPs that could serve as putative active components of A. cochinchinensis that prevented gut injury. Altogether, the results of our study provide evidence that A. cochinchinensis might be an effective phytomedicine for the treatment of metal ion-induced gut injury.

  10. Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis.

    Science.gov (United States)

    Krokhin, O V; Kuzina, O V; Hoshino, H; Shpigun, O A; Yotsuyanagi, T

    2000-08-25

    Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal-HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40,000-400,000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(H), Fe(II) ions in reaction with HBED have been discussed.

  11. [Applications of atomic emission spectrum from liquid electrode discharge to metal ion detection].

    Science.gov (United States)

    Mao, Xiu-Ling; Wu, Jian; Ying, Yi-Bin

    2010-02-01

    The fast and precise detection of metal ion is an important research project concerning studies in diverse academic fields and different kinds of detecting technologies. In the present paper, the authors review the research on atomic emission spectrum based on liquid electrode discharge and its applications in the detection of metal ion. In the first part of this paper the principles and characteristics of the methods based on electrochemistry and spectroscopy were introduced. The methods of ion-selective electrode (ISE), anodic stripping voltammetry, atomic emission spectrum and atomic absorption spectrum were included in this part and discussed comparatively. Then the principles and characteristics of liquid electrode spectra for metal ion detection were introduced. The mechanism of the plasma production and the characteristics of the plasma spectrum as well as its advantages compared with other methods were discussed. Secondly, the authors divided the discharge system into two types and named them single liquid-electrode discharge and double-liquid electrode respectively, according to the number of the liquid electrode and the configuration of the discharge system, and the development as well as the present research status of each type was illustrated. Then the characteristics and configurations of the discharge systems including ECGD, SCGD, LS-APGD and capillary discharge were discussed in detail as examples of the two types. By taking advantage of the technology of atomic emission spectrum based on liquid electrode discharge, the detecting limit of heavy metals such as copper, mercury and argent as well as active metal ions including sodium, potass and magnesium can achieve microg x L(-1). Finally, the advantages and problems of the liquid-electrode discharge applied in detection of metal ion were discussed. And the applications of the atomic emission spectrum based on liquid electrode discharge were prospected.

  12. Polymer-supported reagents with enhanced metal ion recognition: Application to separations science

    International Nuclear Information System (INIS)

    Alexandratos, S.D.

    1993-01-01

    The design and development of polymer-supported reagents with ever-increasing specificities for targeted metal ions remains an important areas of research. The need for efficient separation schemes for both ions and molecules has been outlined in a report by the National Research Council (King) and will gain increased emphasis as environmental restoration is pursued. Polymer-supported reagents are unique in their ability to be applied in an environmentally benign manner to a host of challenges. Such reagents, in the form of beads, can be applied to continuous separation processes ranging from the removal of metal ions in water to the recovery of medicinal drugs produced through biotechnological means. The application of polymer-supported reagents to metal ion separations still requires developing a fundamental understanding of ligand-metal interactions, the role of the polymer in those interactions, and the methods of synthesizing such polymeric reagents in a readily applicable form. Ion exchange resins with sulfonic acid ligands are the prototypical polymer-supported reagents, and their properties have been exhaustively studied (Helfferich). The high acidity of the sulfonic acid group, however, precludes much selectivity, and it displays a very limited range of reaction free energy values with different metal ions (Boyd et al.). The carboxylic acid ligand, present in the acrylate resins, is more selective, though its weak acidity requires relatively high pH solutions for it to be effective. Research has thus been focused on the preparation of polymer-supported reagents with high levels of specificity for targeted metal ions

  13. Inhibition of cellulase-catalyzed lignocellulosic hydrolysis by iron and oxidative metal ions and complexes.

    Science.gov (United States)

    Tejirian, Ani; Xu, Feng

    2010-12-01

    Enzymatic lignocellulose hydrolysis plays a key role in microbially driven carbon cycling and energy conversion and holds promise for bio-based energy and chemical industries. Cellulases (key lignocellulose-active enzymes) are prone to interference from various noncellulosic substances (e.g., metal ions). During natural cellulolysis, these substances may arise from other microbial activities or abiotic events, and during industrial cellulolysis, they may be derived from biomass feedstocks or upstream treatments. Knowledge about cellulolysis-inhibiting reactions is of importance for the microbiology of natural biomass degradation and the development of biomass conversion technology. Different metal ions, including those native to microbial activity or employed for biomass pretreatments, are often tested for enzymatic cellulolysis. Only a few metal ions act as inhibitors of cellulases, which include ferrous and ferric ions as well as cupric ion. In this study, we showed inhibition by ferrous/ferric ions as part of a more general effect from oxidative (or redox-active) metal ions and their complexes. The correlation between inhibition and oxidation potential indicated the oxidative nature of the inhibition, and the dependence on air established the catalytic role that iron ions played in mediating the dioxygen inhibition of cellulolysis. Individual cellulases showed different susceptibilities to inhibition. It is likely that the inhibition exerted its effect more on cellulose than on cellulase. Strong iron ion chelators and polyethylene glycols could mitigate the inhibition. Potential microbiological and industrial implications of the observed effect of redox-active metal ions on enzymatic cellulolysis, as well as the prevention and mitigation of this effect in industrial biomass conversion, are discussed.

  14. Polydopamine-mediated surface-functionalization of graphene oxide for heavy metal ions removal

    International Nuclear Information System (INIS)

    Dong, Zhihui; Zhang, Feng; Wang, Dong; Liu, Xia; Jin, Jian

    2015-01-01

    By utilizing polydopamine (PD) nano-thick interlayer as mediator, polyethylenimine (PEI) brushes with abundant amine groups were grafted onto the surface of PD coated graphene oxide (GO) uniformly via a Michael-Addition reaction and produced a PEI–PD/GO composite nanosheets. The PEI–PD/GO composite exhibited an improved performance for adsorption of heavy metal ions as compared to PEI-coated GO and pure GO. The adsorption capacities for Cu 2+ , Cd 2+ , Pb 2+ , Hg 2+ are up to 87, 106, 197, and 110 mg/g, respectively. To further make the GO based composite operable, PEI–PD/RGO aerogel was prepared through hydrothermal and achieved a high surface area up to 373 m 2 /g. Although the adsorption capacity of PEI–PD/RGO aerogel for heavy metal ions decreases a little as compared to PEI–PD/GO composite dispersion (38, 32, 95, 113 mg/g corresponding to Cu 2+ , Cd 2+ , Pb 2+ , and Hg 2+ , respectively), it could be recycled several times in a simple way by releasing adsorbed metal ions, indicating its potential application for cleaning wastewater. - Graphical abstract: Polyethylenimine (PEI) brushes were grafted onto the surface of graphene oxide (GO) uniformly via a Michael-Addition reaction between the PEI and polydopamine interlayer coated on GO surface. The PEI–PD/GO composite exhibited an improved performance for adsorption of heavy metal ions compared to PEI-coated GO and pure GO. - Highlights: • We prepared polyethylenimine grafted polydopamine-mediated graphene oxide composites. • Introduction of PD layer increases metal ions adsorption capacity. • PEI–PD/RGO aerogel exhibited a superior adsorption performance. • PEI–PD/RGO aerogel can be recycled several times in a simple way

  15. Effects of complexing compounds on sorption of metal ions to cement

    Energy Technology Data Exchange (ETDEWEB)

    Loevgren, Lars [Umeaa Univ. (Sweden). Inorganic chemistry

    2005-12-15

    This present report is a literature review addressing the effects of complexing ligands on the sorption of radionuclides to solid materials of importance for repositories of radioactive waste. Focus is put on laboratory studies of metal ion adsorption to cement in presence of chelating agents under strongly alkaline conditions. As background information, metal sorption to different mineral and cement phases in ligand free systems is described. Furthermore, surface complexation model (SCM) theories are introduced. According to surface complexation theories these interactions occur at specific binding sites at the particle/water interface. Adsorption of cationic metals is stronger at high pH, and the adsorption of anions occurs preferentially at low pH. The adsorption of ions to mineral surfaces is a result of both chemical bonding and electrostatic attraction between the ions and charged mineral surfaces. By combining uptake data with spectroscopic information the sorption can be explained on a molecular level by structurally sound surface complexation models. Most of the metal sorption studies reviewed are dealing with minerals exhibiting oxygen atoms at their surfaces, mainly oxides of Fe(II,III) and Al(III), and aluminosilicates. Investigations of radionuclides are focused on clay minerals, above all montmorillonite and illite. Which mechanism that is governing the metal ion adsorption to a given mineral is to a large extent depending on the metal adsorbed. For instance, sorption of Ni to montmorillonite can occur by formation of inner-sphere mononuclear surface complexes located at the edges of montmorillonite platelets and by formation of a Ni phyllosilicate phase parallel to montmorillonite layers. Also metal uptake to cement materials can occur by different mechanisms. Cationic metals can both be attached to cement (calcium silicate hydrate, CSH) and hardened cement paste (HCP) by formation of inner-sphere complexes at specific surface sites and by

  16. Novel Glucose-1-Phosphatase with High Phytase Activity and Unusual Metal Ion Activation from Soil Bacterium Pantoea sp. Strain 3.5.1.

    Science.gov (United States)

    Suleimanova, Aliya D; Beinhauer, Astrid; Valeeva, Liia R; Chastukhina, Inna B; Balaban, Nelly P; Shakirov, Eugene V; Greiner, Ralf; Sharipova, Margarita R

    2015-10-01

    Phosphorus is an important macronutrient, but its availability in soil is limited. Many soil microorganisms improve the bioavailability of phosphate by releasing it from various organic compounds, including phytate. To investigate the diversity of phytate-hydrolyzing bacteria in soil, we sampled soils of various ecological habitats, including forest, private homesteads, large agricultural complexes, and urban landscapes. Bacterial isolate Pantoea sp. strain 3.5.1 with the highest level of phytase activity was isolated from forest soil and investigated further. The Pantoea sp. 3.5.1 agpP gene encoding a novel glucose-1-phosphatase with high phytase activity was identified, and the corresponding protein was purified to apparent homogeneity, sequenced by mass spectroscopy, and biochemically characterized. The AgpP enzyme exhibits maximum activity and stability at pH 4.5 and at 37°C. The enzyme belongs to a group of histidine acid phosphatases and has the lowest Km values toward phytate, glucose-6-phosphate, and glucose-1-phosphate. Unexpectedly, stimulation of enzymatic activity by several divalent metal ions was observed for the AgpP enzyme. High-performance liquid chromatography (HPLC) and high-performance ion chromatography (HPIC) analyses of phytate hydrolysis products identify dl-myo-inositol 1,2,4,5,6-pentakisphosphate as the final product of the reaction, indicating that the Pantoea sp. AgpP glucose-1-phosphatase can be classified as a 3-phytase. The identification of the Pantoea sp. AgpP phytase and its unusual regulation by metal ions highlight the remarkable diversity of phosphorus metabolism regulation in soil bacteria. Furthermore, our data indicate that natural forest soils harbor rich reservoirs of novel phytate-hydrolyzing enzymes with unique biochemical features. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Studies on the biofilm produced by Pseudomonas aeruginosa grown in different metal fatty acid salt media and its application in biodegradation of fatty acids and bioremediation of heavy metal ions.

    Science.gov (United States)

    Abinaya Sindu, P; Gautam, Pennathur

    2017-01-01

    Metal fatty acid salts (MFAS) in untreated industrial effluents cause environmental pollution. The use of biocompatible agents for remediation may help in reducing the harm caused to the ambient aquatic organism. Pseudomonas aeruginosa is a ubiquitous organism that thrives under harsh conditions and is resistant to toxic metal ions. The present study shows a proof-of-concept of using this organism in the biodegradation of MFAS. MFAS were prepared and we studied their effect on the growth of the planktonic form and the formation of biofilm by P. aeruginosa. We observed biofilm formation in the presence of all the MFAS when used as the sole carbon source, albeit the quantity of biofilm formed in the presence of cadmium and copper was less. There was no effect on the planktonic form of the organism but the formation of biofilm increased in the presence of magnesium palmitate. This study shows that metal ions play a pivotal role in the formation of biofilm. HPLC (high-performance liquid chromatography) analysis of the biofilm polysaccharide showed that hexose sugar was a major component when compared with pentose sugar. The structure of biofilm polysaccharide and the coordination of the metal ion with the biofilm polysaccharide were confirmed by FTIR (Fourier transform infrared spectroscopy) and Raman spectroscopy.

  18. Mutational analysis of divalent metal ion binding in the active site of class II α-mannosidase from sulfolobus solfataricus

    DEFF Research Database (Denmark)

    Hansen, Dennis K.; Webb, Helen; Nielsen, Jonas Willum

    2015-01-01

    Mutational analysis of Sulfolobus solfataricus class II α-mannosidase was focused on side chains that interact with the hydroxyls of the-1 mannosyl of the substrate (Asp-534) or form ligands to the active site divalent metal ion (His-228 and His-533) judged from crystal structures of homologous e......, although less dramatically with some activating metal ions. No major differences in the pH dependence between wild-type and mutant enzymes were found in the presence of different metal ions. The pH optimum was 5, but enzyme instability was observed at pH...

  19. Metal ion interaction of an oligopeptide fragment representing the regulatory metal binding site of a CueR protein

    DEFF Research Database (Denmark)

    Jancsó, Attila; Szokolai, Hajnalka; Roszahegyi, Livia

    2013-01-01

    Metalloregulatory proteins of the MerR family are transcriptional activators that sense/control the concentration of various metal ions inside bacteria.1 The Cu+ efflux regulator CueR, similarly to other MerR proteins, possesses a short multiple Cys-containing metal binding loop close to the C...... of cognate metal ions.2 Nevertheless, it is an interesting question whether the same sequence, when removed from the protein, shows a flexibility to adopt different coordination environments and may efficiently bind metal ions having preferences for larger coordination numbers....

  20. Hydration number of alkali metal ions determined by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2008-01-01

    of all other water molecules whose properties are still influenced significantly by the cation. Knowing the hydration number is important when considering, for instance, the transport of Na+ and K+ in biological cell membranes, since their different behavior may depend on the details of ion hydration....... The solvation of alkali metal ions has been discussed for many years without a clear consensus. This work presents a systematic study of the hydration numbers of the 5 alkali metal ions, using the electrochemical insertion of the ions in a conducting polymer (polypyrrole containing the large immobile anion DBS...... direct calculation of the number of M+ ions entering the film, and therefore the inserted M+ mass. The mass of the water molecules is calculated as a difference. The results yield the following primary hydration numbers: Li+: 5.5-5.6; Na+: 4.0-4.1; K+: 2.0-2.5; Rb+: 0.6-1.2; Cs+: ~0. The most important...

  1. Determination of membrane hydration numbers of alkali metal ions by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen; Junaid Mohamed Jafeen, Mohamed; Careem, M.A.

    2010-01-01

    , and a secondary (or outer) solvation shell, consisting of all other water molecules whose properties are still influenced significantly by the cation. Knowing the hydration number is important when considering, for instance, the transport of Na+ and K+ in biological cell membranes, since their different behavior...... may depend on the details of ion hydration. Although the solvation of alkali metal ions in aqueous solution has been discussed for many years, there is still no clear consensus. Part of the discrepancy is simply that different methods measure over different time scales, and therefore do...... not necessarily define the same hydration shell. This work presents a systematic study of one special variant of the hydration numbers of the 5 alkali metal ions, using the electrochemical insertion of the ions in a conducting polymer (polypyrrole containing the large immobile anion DBS-). The technique...

  2. Study on the adsorption of heavy metal ions from aqueous solution on modified SBA-15

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2013-01-01

    Full Text Available Amino-functionalized SBA-15 mesoporous silica was prepared, characterized, and used as an adsorbent for heavy metal ions. The organic - inorganic hybrid material was obtained by a grafting procedure using SBA-15 silica with 3-aminopropyl-triethoxysilane and bis(2,4,4-trimethylpentyl phosphinic acid (Cyanex 272, respectively. The structure and physicochemical properties of the materials were characterized by means of elemental analysis, X-ray diffraction (XRD, nitrogen adsorption - desorption, thermogravimetric analysis, FTIR spectroscopy and immersion calorimetry. The organic functional groups were successfully grafted onto the SBA-15 surface and the ordering of the support was not affected by the chemical modification. The behavior of the grafted solids was investigated for the adsorption of heavy metal ions from aqueous solutions. The hybrid materials showed high adsorption capacity and high selectivity for zinc ions. Other ions, such as cooper and cobalt were absorbed by the modified SBA-15 material.

  3. Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihe; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

    2015-05-15

    Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases.

  4. Detection of metal ions by atomic emission spectroscopy from liquid-electrode discharge plasma

    International Nuclear Information System (INIS)

    Wu Jian; Yu Jing; Li Jun; Wang Jianping; Ying Yibin

    2007-01-01

    In this paper, the discharge ignited in a capillary connecting two beakers filled with electrolyte solution is investigated. During the experiment, an external electrical voltage is applied through two platinum electrodes dipped in the beakers. A gas bubble forms inside the capillary when the applied voltage is higher than 1000 V. Since the beakers are tilted slightly, after generation, the bubble moves slowly to the uphill outlet of the capillary due to buoyancy. When the bubble reaches the end of the capillary, it cracks and a bright discharge is ignited. The emission spectra of the discharge plasma are related to the metal ions dissolved in the solution and thus can be used for metal ion detection. An application of the system to measurement of water hardness is shown

  5. Sensing of heavy metal ions by intrinsic TMV coat protein fluorescence

    Science.gov (United States)

    Bayram, Serene S.; Green, Philippe; Blum, Amy Szuchmacher

    2018-04-01

    We propose the use of a cysteine mutant of TMV coat protein as a signal transducer for the selective sensing and quantification of the heavy metal ions, Cd2+, Pb2+, Zn2+ and Ni2+ based on intrinsic tryptophan quenching. TMV coat protein is inexpensive, can be mass-produced since it is expressed and extracted from E-coli. It also displays several different functional groups, enabling a wide repertoire of bioconjugation chemistries; thus it can be easily integrated into functional devices. In addition, TMV-ion interactions have been widely reported and utilized for metallization to generate organic-inorganic hybrid composite novel materials. Building on these previous observations, we herein determine, for the first time, the TMV-ion binding constants assuming the static fluorescence quenching model. We also show that by comparing TMV-ion interactions between native and denatured coat protein, we can distinguish between chemically similar heavy metal ions such as cadmium and zinc ions.

  6. Metal-Ion-Mediated Supramolecular Chirality of l-Phenylalanine Based Hydrogels.

    Science.gov (United States)

    Wang, Fang; Feng, Chuan-Liang

    2018-05-14

    For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l-phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Screen-printed electrodes for environmental monitoring of heavy metal ions: a review

    International Nuclear Information System (INIS)

    Barton, John; González García, María Begoña; Hernández Santos, David; Fanjul-Bolado, Pablo; Ribotti, Alberto; Magni, Paolo; McCaul, Margaret; Diamond, Dermot

    2016-01-01

    Heavy metals such as lead, mercury, cadmium, zinc and copper are among the most important pollutants because of their non-biodegradability and toxicity above certain thresholds. Here, we review methods for sensing heavy metal ions (HMI) in water samples using screen-printed electrodes (SPEs) as transducers. The review (with 107 refs.) starts with an introduction into the topic, and this is followed by sections on (a) mercury-coated SPEs, (b) bismuth-coated SPEs, (c) gold-coated SPEs (d) chemically modified and non-modified carbon SPEs, (e) enzyme inhibition-based SPEs, and (f) an overview of commercially available electrochemical portable heavy metal analyzers. The review reveals the significance of SPEs in terms of decentralized and of in situ analysis of heavy metal ions in environmental monitoring. (author)

  8. Separation and Extraction of Some Heavy and Toxic Metal Ions from Their Wastes by Ionic Membranes

    International Nuclear Information System (INIS)

    El-Sayed Hegazy, A.; Kamal, H.; Mahmoud, Gh. A.; Khalifa, N.A.

    1999-01-01

    Preparation and characterisation of a series of ion-exchange membranes for the purpose of separation and extraction of some heavy and toxic metal ions from their wastes have been studied. Such ion exchange membranes prepared by γ-radiation grafting of acrylonitrile (AN) and vinyl acetate (VAc) in a binary monomers mixture onto low density polyethylene (LDPE) using direct technique of grafting. The reaction conditions at which grafting process proceeds successfully have been determined. Many modification treatments have been attempted for the prepared membranes to improve their ion-exchange properties. The possibility of their practical use in waste water treatment from some heavy and toxic metal ions such as Pb 2+ , Cd 2+ ,Cu 2+ ,Fe 3+ ,Sr 2+ and Li + have been investigated. These grafted membranes showed great promise for its use in the field of extraction and removal of some heavy and toxic metals from their wastes

  9. Competition of dipositive metal ions for Fe (III) binding sites in chelation therapy of Iron Load

    International Nuclear Information System (INIS)

    Rehmani, Fouzia S.

    2005-01-01

    Iron overload is a condition in which excessive iron deposited in the liver, kidney and spleen of human beings in the patients of beta thalassemia and sickle cell anemia. Instead of its importance iron could be toxic when in excess, it damages the tissues. For the treatment of iron overload, a drug desferrioxamine mesylate has been used. It is linear trihydroxamic acid, a natural siderophore produced by streptomyces which removes the extra iron from body. Salicylhydroxamate type siderphore. In present research salicylhydroxamate was used for the complexation with dipositive metal ions which are available in biological environments such as Mn (II), Co (II), Ni (II) and Cu (II). The aim of our work was to study the competition reactions between Fe (III) and other dipositive ions; to calculate the thermodynamic data of chelation of these metal ions complexes with hydroxamate by computer program and comparison with hydroxamate complexes. (author)

  10. Decontamination of Metal Ions in Soil by Supercritical CO2 Extraction with Crown Ether

    International Nuclear Information System (INIS)

    Park, Jihe; Park, Kwangheon

    2015-01-01

    Previous decontamination methods have shortcomings in that they produce additional waste due to the usage of solutions with chemical toxicity. Hence, demand is strong for new decontamination methods that can guarantee effective decontamination while decreasing the chemical solution. In particular, methods using supercritical CO2 as a means of decontamination are currently in progress. This study examines the method of decontaminating metallic ions inside soil using supercritical CO2. This paper examined the effects of extracting metallic ions inside soil using supercritical CO2 and crown ether as the ligand. It was confirmed that extraction effectiveness increases following greater usage of ligand and co-ligand, with a drastic increase in extraction effectiveness when using extracts over a certain dose. Moreover, it was shown that if the usage of ligand and additive decreases, the extraction ratio also decreases

  11. Preparation of poly(acrylic acid)-chitosan hydrogels by gamma irradiation for metal ions sorption

    International Nuclear Information System (INIS)

    Tran Thu Hong; Le Hai; Nguyen Tan Man; Tran Thi Tam; Pham Thi Le Ha; Pham Thi Sam; Nguyen Duy Hang; Le Huu Tu; Le Van Toan

    2013-01-01

    Acid acrylic (AAc) was grafted onto crosslinked chitosan to make Chitosan-g-AAc copolymer with concentration of AAc from 0.5 to 15% by gamma irradiation. The optimal dose for grafting of 15% AAc onto chitosan was 5 kGy. Physical and chemical properties of irradiated samples such as SEM images, FTIR spectroscopy, TGA and swelling behavior at different pHs were evaluated. The grafting yield increased with the increase in dose, it reached 52% at 7 kGy irradiation dose. The application were grafted materials to adsorb metals ion from aqueous solutions was also investigated with both ungrafted and grafted chitosan beads under changing pH from 3 to 6. Grafted chitosan presented higher sorption capacity for most of metal ions than unmodified chitosan. (author)

  12. Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

    International Nuclear Information System (INIS)

    Resta, V.; Quarta, G.; Farella, I.; Maruccio, L.; Cola, A.; Calcagnile, L.

    2014-01-01

    The implantation of 1 MeV metal ( 63 Cu + , 107 Ag + , 197 Au + ) and non-metal ( 4 He + , 12 C + ) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10 13 ions cm −2 , the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10 17 ions cm −2 , the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C 0x clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C 0x cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10 7 Ω/sq has been measured for implantation with metals at doses higher than 5 × 10 16 ions cm −2 , being 10 17 Ω/sq the corresponding sheet resistance for pristine PC

  13. Synthesis of Zeolite from Fly Ash and Removal of Heavy Metal Ions from Newly Synthesized Zeolite

    OpenAIRE

    Solanki, Parag; Gupta, Vikal; Kulshrestha, Ruchi

    2010-01-01

    Coal fly ash was used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. Characteristics of the various Fly ash samples were carried out. Coal proximate analysis was done. Batch experiment was carried out for the adsorption of some heavy metal ions on to synthesized Zeolite. The cost of synthesized zeolite was estimated to be almost one-fifth of that of commercial 13X zeolite available in the market.

  14. Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Resta, V., E-mail: vincenzo.resta@le.infn.it [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Quarta, G. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Farella, I. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Maruccio, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Cola, A. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Calcagnile, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy)

    2014-07-15

    The implantation of 1 MeV metal ({sup 63}Cu{sup +}, {sup 107}Ag{sup +}, {sup 197}Au{sup +}) and non-metal ({sup 4}He{sup +}, {sup 12}C{sup +}) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10{sup 13} ions cm{sup −2}, the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10{sup 17} ions cm{sup −2}, the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C{sub 0x} clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C{sub 0x} cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10{sup 7} Ω/sq has been measured for implantation with metals at doses higher than 5 × 10{sup 16} ions cm{sup −2}, being 10{sup 17} Ω/sq the corresponding sheet resistance for pristine PC.

  15. Chromatographic separation of metal ions by means of paper treated with trioctyl - phosphate, Annex 7

    Energy Technology Data Exchange (ETDEWEB)

    Cvjeticanin, N M; Cvoric, J D; Obrenovic-Paligoric, I D [Institute of Nuclear Sciences Boris Kidric, Laboratorija za visoku aktivnost, Vinca, Beograd (Serbia and Montenegro)

    1963-12-15

    This chromatographic behaviour of uranium, thorium and some other metal ions and long-lived fission products was investigated on paper treated with trioctyl-phosphate. Hydrochloric, nitric, sulphuric and perchloric acids in concentrations of 0.1-10 N were used as the elution agents. The R{sub f} values of the ions investigated, which show the possibility of the inter separation of some cations, are given as a function of the concentration of acids (author)

  16. EFFECT OF HEAVY METAL IONS ON THE NUMBER AND ACTIVITY OF Azotobacter AND MELANINSYNTHESIZING MICROMYCETES

    OpenAIRE

    Malynovska I. M.

    2017-01-01

    The aim of the work was to determine the possibility of using the number and activity of Azotobacter cells and melanin-synthesizing micromycetes as indicators of gray forest soils of different types (fallow, extensive and intensive agrosoil) pollution with heavy metal ions. For this purpose, there were used laboratory-analytical, microbiological and statistical methods. As a result of research of increasing doses of heavy metals (zinc + lead) influence on the number of microorganisms in the g...

  17. Modulation of individual steps in group I intron catalysis by a peripheral metal ion.

    Science.gov (United States)

    Forconi, Marcello; Piccirilli, Joseph A; Herschlag, Daniel

    2007-10-01

    Enzymes are complex macromolecules that catalyze chemical reactions at their active sites. Important information about catalytic interactions is commonly gathered by perturbation or mutation of active site residues that directly contact substrates. However, active sites are engaged in intricate networks of interactions within the overall structure of the macromolecule, and there is a growing body of evidence about the importance of peripheral interactions in the precise structural organization of the active site. Here, we use functional studies, in conjunction with published structural information, to determine the effect of perturbation of a peripheral metal ion binding site on catalysis in a well-characterized catalytic RNA, the Tetrahymena thermophila group I ribozyme. We perturbed the metal ion binding site by site-specifically introducing a phosphorothioate substitution in the ribozyme's backbone, replacing the native ligands (the pro-R (P) oxygen atoms at positions 307 and 308) with sulfur atoms. Our data reveal that these perturbations affect several reaction steps, including the chemical step, despite the absence of direct contacts of this metal ion with the atoms involved in the chemical transformation. As structural probing with hydroxyl radicals did not reveal significant change in the three-dimensional structure upon phosphorothioate substitution, the effects are likely transmitted through local, rather subtle conformational rearrangements. Addition of Cd(2+), a thiophilic metal ion, rescues some reaction steps but has deleterious effects on other steps. These results suggest that native interactions in the active site may have been aligned by the naturally occurring peripheral residues and interactions to optimize the overall catalytic cycle.

  18. Integrated Microanalytical System for Simultaneous Voltammetric Measurements of Free Metal Ion Concentrations in Natural Waters

    OpenAIRE

    Noël, Stéphane; Tercier-Waeber, Mary-Lou; Lin, Lin; Buffle, Jacques; Guenat, Olivier; Koudelka-Hep, Milena

    2007-01-01

    A complexing gel integrated microelectrode (CGIME) for direct measurements of free metal ion concentrations in natural waters has been developed. It is prepared by the successive deposition of microlayers of a chelating resin, an antifouling agarose gel and Hg on a 100-interconnected Ir-based microelectrode array. The trace metals of interest are in a first step accumulated on the chelating resin in proportion to their free ion concentration in solution, then released in acidic solution and d...

  19. Elaboration and test of the method of separation of alkaline metals ions with tin phosphate

    International Nuclear Information System (INIS)

    Smirnov, G.I.; Chernyak, A.S.; Kostromina, O.N.; Kachur, N.Ya.; Shpeyzer, B.G.

    1986-01-01

    Present work is devoted to elaboration and test of the method of separation of alkaline metals ions with tin phosphate. Thus, the isotherms of sorption of lithium, sodium, potassium, rubidium and cesium ions with amorphous tin phosphate depending on their concentration, ph of solution, sorbent quantity are obtained. The parameters of extraction of potassium microquantities from sodium salts are defined. Ultra pure sodium chloride, sodium iodide, sodium sulphate, sodium nitrate, sodium nitrite, sodium phosphate are synthesized.

  20. Biosensor and chemical sensor probes for calcium and other metal ions

    Science.gov (United States)

    Vo-Dinh, Tuan; Viallet, Pierre

    1996-01-01

    The present invention relates to chemical sensor and biosensor probes for measuring low concentration of metals and metal ions in complex samples such as biological fluids, living cells, and environmental samples. More particularly the present invention relates to a gel-based Indo-1 and Fura-2 chemical sensor probes for the measurement of low concentrations of calcium, cadmium, magnesium and the like. Also disclosed is a detector device using the sensors of the present invention.

  1. Optical and electronic properties of polyvinyl alcohol doped with pairs of mixed valence metal ions

    International Nuclear Information System (INIS)

    Bulinski, Mircea; Kuncser, Victor; Plapcianu, Carmen; Krautwald, Stefan; Franke, Hilmar; Rotaru, P; Filoti, George

    2004-01-01

    The electronic mechanisms induced by the UV exposure of thin films of polyvinyl alcohol doped with pairs of mixed valence metal ions were studied in relation to their optical behaviour by Moessbauer spectroscopy and optical absorption. The results obtained definitely point to the role of each element from the pair in the electronic mechanism involved, with influence on the optical properties regarding applications in real-time holography and integrated optics

  2. Metal-ion interactions and the structural organization of Sepia eumelanin.

    Science.gov (United States)

    Liu, Yan; Simon, John D

    2005-02-01

    The structural organization of melanin granules isolated from ink sacs of Sepia officinalis was examined as a function of metal ion content by scanning electron microscopy and atomic force microscopy. Exposing Sepia melanin granules to ethelenediaminetetraacetic acid (EDTA) solution or to metal salt solutions changed the metal content in the melanin, but did not alter granular morphology. Thus ionic forces between the organic components and metal ions in melanin are not required to sustain the natural morphology once the granule is assembled. However, when aqueous suspensions of Sepia melanin granules of varying metal content are ultra-sonicated, EDTA-washed and Fe-saturated melanin samples lose material to the solution more readily than the corresponding Ca(II) and Mg(II)-loaded samples. The solubilized components are found to be 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-rich constituents. Associated with different metal ions, Na(I), Ca(II) and Mg(II) or Fe(III), these DHICA-rich entities form distinct two-dimensional aggregation structures when dried on the flat surface of mica. The data suggest multiply-charged ions play an important role in assisting or templating the assembly of the metal-free organic components to form the three-dimensional substructure distributed along the protein scaffold within the granule.

  3. Metal ion reactive thin films using spray electrostatic LbL assembly.

    Science.gov (United States)

    Krogman, Kevin C; Lyon, Katharine F; Hammond, Paula T

    2008-11-20

    By using the spray-layer-by-layer (Spray-LbL) technique, the number of metal counterions trapped within LbL coatings is significantly increased by kinetically freezing the film short of equilibrium, potentially limiting interchain penetration and forcing chains to remain extrinsically compensated to a much greater degree than observed in the traditional dipped LbL technique. The basis for the enhanced entrapment of metal ions such as Cu2+, Fe2+, and Ag+ is addressed, including the equilibrium driving force for extrinsic compensation by soft versus hard metal ions and the impact of Spray-LbL on the kinetics of polymer-ion complexation. These polymer-bound metal-ion coatings are also demonstrated to be effective treatments for air filtration, functionalizing existing filters with the ability to strongly bind toxic industrial compounds such as ammonia or cyanide gases, as well as chemical warfare agent simulants such as chloroethyl ethyl sulfide. On the basis of results reported here, future work could extend this method to include other toxic soft-base ligands such as carbon monoxide, benzene, or organophosphate nerve agents.

  4. Selective recovery of gold and other metal ions from an algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Darnall, D.W.; Greene, B.; Henzl, M.T.; Hosea, J.M.; McPherson, R.A.; Sneddon, J.; Alexander, M.D.

    1986-02-01

    The authors observed that the pH dependence of the binding of Au/sup 3 +/, Ag/sup +/, and Hg/sup 2 +/ to the algae Chlorella vulgaris is different than the binding of other metal ions. Between pH 5 and 7, a variety of metal ions bind strongly to the cell surface. Most of these algal-bound metal ions can be selectively desorbed by lowering the pH to 2; however, Au/sup 3 +/, Hg/sup 2 +/, and Ag/sup +/ are all bound strongly at pH 2. Addition of a strong ligand at different pHs is required to elute these ions from the algal surface. Algal-bound gold and mercury can be selectively eluted by using mercaptoethanol. An elution scheme is demonstrated for the binding and selective recovery of Cu/sup 2 +/, Zn/sup 2 +/, Au/sup 3 +/, and Hg/sup 2 +/ from an equimolar mixture. 20 references, 2 figures.

  5. Investigation of metal ion extraction and aggregate formation combining acidic and neutral organophosphorous reagents

    Energy Technology Data Exchange (ETDEWEB)

    Braatz, A.D.; Nilsson, M. [Department of Chemical Engineering and Materials Science, 916 Engineering Tower, University of California-Irvine, Irvine, CA 92697-2575 (United States); Ellis, R.; Antonio, M. [Chemical Science and Engineering Division, Argonne National Laboratory, Building 200 9700 South Cass Ave, Argonne, IL 60439-4831 (United States)

    2013-07-01

    In the present study, we investigate how varying mixtures of tri-n-butyl phosphate (TBP) and dibutyl phosphate (HDBP) results in enhanced extraction of lanthanum(III), La{sup 3+}, and dysprosium(III), Dy{sup 3+}. Water and metal ion extraction were carefully monitored as a function of TBP:HDBP mole ratio.In addition to these techniques, EXAFS was used to determine the coordination environment of the metal ion in this system. To produce the necessary signal, a concentration of 1.25*10{sup -3} M La{sup 3+} and Dy{sup 3+} was used. Although previous studies of synergistic extraction of metal cations using combinations of neutral and acidic reagents explain the enhanced extraction by increased dehydration of the metal ion and the formation of mixed extractant complexes, our evidence for the increased water extraction coupled with the aggregate formation suggests a reverse micellar aspect to synergism in the system containing TBP and HDBP. It is quite possible that both of these phenomena contribute to our system behavior. The EXAFS data shows that, based on coordination numbers alone, several possible structures may exist. From this study, we cannot provide a definitive answer as to the nature of extraction in this system or the exact complex formed during extraction.

  6. Selective recognition by novel calix system: ICT based chemosensor for metal ions

    International Nuclear Information System (INIS)

    Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K.

    2014-01-01

    A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant

  7. Removal of heavy metal ions from wastewaters using dendrimer-functionalized multi-walled carbon nanotubes.

    Science.gov (United States)

    Iannazzo, Daniela; Pistone, Alessandro; Ziccarelli, Ida; Espro, Claudia; Galvagno, Signorino; Giofré, Salvatore V; Romeo, Roberto; Cicero, Nicola; Bua, Giuseppe D; Lanza, Giuseppe; Legnani, Laura; Chiacchio, Maria A

    2017-06-01

    Dendrimer-functionalized multi-walled carbon nanotubes (MWCNT) for heavy metal ion removal from wastewaters were developed. Triazole dendrimers (TD) were built directly onto the carbon nanotube surface by successive click chemistry reactions affording the zero- and first-generation dendrimer-functionalized MWCNT (MWCNT-TD1 and MWCNT-TD2). The Moedritzer-Irani reaction carried out on the amino groups present on the MWCNT-TD2 sample gave the corresponding α-aminophosphonate nanosystem MWCNT-TD2P. Both MWCNT-TD2 and MWCNT-TD2P nanosystems have been characterized by physical, chemical, and morphological analyses. Their chelating abilities towards the toxic metal ions Pb 2+ , Hg 2+ , and Ni 2+ and the harmless Ca 2+ ion have been experimentally evaluated in the two different sets of experiments and at the salt concentrations of 1 mg/mL or 1 μg/mL by inductively coupled plasma mass spectrometry (ICP-MS). The results of these studies pointed out the interesting chelating behavior for the phosphonated nanosystem towards the Hg 2+ ion. The complexation mode of the best chelating system MWCNT-TD2P with mercury was investigated through density functional theory (DFT) calculations, suggesting a chelation mechanism involving the two oxygen atoms of the phosphate group. The synthesized dendrimers, supported on the multi-walled carbon nanotubes, have shown the potential to be used for the selective toxic metal ion removal and recovery.

  8. Selective recognition by novel calix system: ICT based chemosensor for metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K., E-mail: drvkjain@hotmail.com

    2014-02-15

    A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant.

  9. Kinetic study of heavy metal ions removal by ion exchange in batch conical air spouted bed

    Directory of Open Access Journals (Sweden)

    T.M. Zewail

    2015-03-01

    Full Text Available Spouted bed contactor is a hybrid of fixed and fluidized bed contactors, which retains the advantages of each with good hydrodynamic conditions. The aim of the present study is to investigate the performance of a batch conical air spouted vessel for heavy metal removal by strong cation exchange resins (AMBERJET 1200 Na. The effect of various parameters such as type of heavy metal ions (Ni+2 and Pb+2, contact time, superficial air velocity and initial heavy metal ion concentration on % heavy metal ion removal has been investigated. It has been found that under optimum conditions 98% and 99% removal of Ni+2 and Pb+2 were achieved respectively. Several kinetic models were used to test the experimental data and to examine the controlling mechanism of the sorption process. The present results of Ni+2 and Pb+2 well fit pseudo second order kinetic model with a high correlation coefficient. Both film diffusion and intra-particle diffusion contribute to the ion exchange process. The present study revealed that spouted bed vessel may provide an effective alternative for conducting ion exchange reactions.

  10. Identification of metal ion binding sites based on amino acid sequences.

    Science.gov (United States)

    Cao, Xiaoyong; Hu, Xiuzhen; Zhang, Xiaojin; Gao, Sujuan; Ding, Changjiang; Feng, Yonge; Bao, Weihua

    2017-01-01

    The identification of metal ion binding sites is important for protein function annotation and the design of new drug molecules. This study presents an effective method of analyzing and identifying the binding residues of metal ions based solely on sequence information. Ten metal ions were extracted from the BioLip database: Zn2+, Cu2+, Fe2+, Fe3+, Ca2+, Mg2+, Mn2+, Na+, K+ and Co2+. The analysis showed that Zn2+, Cu2+, Fe2+, Fe3+, and Co2+ were sensitive to the conservation of amino acids at binding sites, and promising results can be achieved using the Position Weight Scoring Matrix algorithm, with an accuracy of over 79.9% and a Matthews correlation coefficient of over 0.6. The binding sites of other metals can also be accurately identified using the Support Vector Machine algorithm with multifeature parameters as input. In addition, we found that Ca2+ was insensitive to hydrophobicity and hydrophilicity information and Mn2+ was insensitive to polarization charge information. An online server was constructed based on the framework of the proposed method and is freely available at http://60.31.198.140:8081/metal/HomePage/HomePage.html.

  11. Polyrhodanine modified anodic aluminum oxide membrane for heavy metal ions removal.

    Science.gov (United States)

    Song, Jooyoung; Oh, Hyuntaek; Kong, Hyeyoung; Jang, Jyongsik

    2011-03-15

    Polyrhodanine was immobilized onto the inner surface of anodic aluminum oxide (AAO) membrane via vapor deposition polymerization method. The polyrhodanine modified membrane was applied to remove heavy metal ions from aqueous solution because polyrhodanine could be coordinated with specific metal ions. Several parameters such as initial metal concentration, contact time and metal species were evaluated systematically for uptake efficiencies of the fabricated membrane under continuous flow condition. Adsorption isotherms of Hg(II) ion on the AAO-polyrhodanine membrane were analyzed with Langmuir and Freundlich isotherm models. The adsorption rate of Hg(II) ion on the membrane was obeyed by a pseudo-second order equation, indicating the chemical adsorption. The maximum removal capacity of Hg(II) ion onto the fabricated membrane was measured to be 4.2 mmol/g polymer. The AAO-polyrhodanine membrane had also remarkable uptake performance toward Ag(I) and Pb(II) ions. Furthermore, the polyrhodanine modified membrane could be recycled after recovery process. These results demonstrated that the polyrhodanine modified AAO membrane provided potential applications for removing the hazardous heavy metal ions from wastewater. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

    Directory of Open Access Journals (Sweden)

    Erica Ciotta

    2017-11-01

    Full Text Available A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu2+, Pb2+ and As(III was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements and transmission electron microscope (TEM images we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III and the formation of precipitate with Pb2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor.

  13. A Mononuclear Non-Heme Manganese(IV)-Oxo Complex Binding Redox-Inactive Metal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Junying; Lee, Yong-Min; Davis, Katherine M.; Wu, Xiujuan; Seo, Mi Sook; Cho, Kyung-Bin; Yoon, Heejung; Park, Young Jun; Fukuzumi, Shunichi; Pushkar, Yulia N.; Nam, Wonwoo [Ewha; (Purdue); (Osaka)

    2013-05-29

    Redox-inactive metal ions play pivotal roles in regulating the reactivities of high-valent metal–oxo species in a variety of enzymatic and chemical reactions. A mononuclear non-heme Mn(IV)–oxo complex bearing a pentadentate N5 ligand has been synthesized and used in the synthesis of a Mn(IV)–oxo complex binding scandium ions. The Mn(IV)–oxo complexes were characterized with various spectroscopic methods. The reactivities of the Mn(IV)–oxo complex are markedly influenced by binding of Sc3+ ions in oxidation reactions, such as a ~2200-fold increase in the rate of oxidation of thioanisole (i.e., oxygen atom transfer) but a ~180-fold decrease in the rate of C–H bond activation of 1,4-cyclohexadiene (i.e., hydrogen atom transfer). The present results provide the first example of a non-heme Mn(IV)–oxo complex binding redox-inactive metal ions that shows a contrasting effect of the redox-inactive metal ions on the reactivities of metal–oxo species in the oxygen atom transfer and hydrogen atom transfer reactions.

  14. Titania-Coated Silica Alone and Modified by Sodium Alginate as Sorbents for Heavy Metal Ions

    Science.gov (United States)

    Kołodyńska, D.; Gęca, M.; Skwarek, E.; Goncharuk, O.

    2018-04-01

    The novel organic-inorganic biohybrid composite adsorbent was synthesized based on nanosized silica-titania modified with alginate within the development of effective adsorbent for heavy metal ions. Effects of metal species Cu(II), Zn(II), Cd(II), and Pb(II); concentrations; pH; temperature; and adsorption onto titania-coated silica (ST20) initial or modified by sodium alginate (ST20-ALG) were studied. The equilibrium and kinetic data of metal ions adsorption were analyzed using Langmuir and Freundlich adsorption models and kinetic models: pseudo first order, pseudo second order, intraparticle kinetic model, and Elovich. The maximum sorption capacities observed were higher for the ST20-ALG composite compared to the initial ST20 oxide for all studied metal ions, namely their values for ST20-ALG were 22.44 mg g- 1 for Cu(II) adsorption, 19.95 mg g- 1 for Zn(II), 18.85 mg g- 1 for Cd(II), and 32.49 mg g- 1 for Pb(II). Structure and properties of initial silica-titania ST20 and modified by sodium alginate ST20-ALG adsorbents were analyzed using nitrogen adsorption/desorption isotherms, ATR-FTIR, SEM-EDS, and pHpzc techniques.

  15. Determination of the total concentration and speciation of metal ions in river, estuarine and seawater samples.

    Science.gov (United States)

    Alberti, Giancarla; Biesuz, Raffaela; Pesavento, Maria

    2008-12-01

    Different natural water samples were investigated to determine the total concentration and the distribution of species for Cu(II), Pb(II), Al(III) and U(VI). The proposed method, named resin titration (RT), was developed in our laboratory to investigate the distribution of species for metal ions in complex matrices. It is a competition method, in which a complexing resin competes with natural ligands present in the sample to combine with the metal ions. In the present paper, river, estuarine and seawater samples, collected during a cruise in Adriatic Sea, were investigated. For each sample, two RTs were performed, using different complexing resins: the iminodiacetic Chelex 100 and the carboxylic Amberlite CG50. In this way, it was possible to detect different class of ligands. Satisfactory results have been obtained and are commented on critically. They were summarized by principal component analysis (PCA) and the correlations with physicochemical parameters allowed one to follow the evolution of the metals along the considered transect. It should be pointed out that, according to our findings, the ligands responsible for metal ions complexation are not the major components of the water system, since they form considerably weaker complexes.

  16. Source of Global Scale Variations in the Midday Vertical Content of Ionospheric Metal Ions

    Science.gov (United States)

    Joiner, J.; Grebowsky, J. M.; Pesnell, W. D.; Aikin, A. C.; Goldberg, Richard A.

    1999-01-01

    An analysis of long baseline NIMBUS 7 SBUV (Solar Backscatter UV Spectrometer) observations of the latitudinal variation of the noontime vertical Mg' content above approx. 70 km have revealed seasonal, solar activity and magnetic activity dependencies in the Mg+ content. The distributions were categorized in terms of magnetic coordinates partially because transport processes lifting metallic ions from the main meteor ionization layer below 100 km up into the F- region and down again are controlled by electrodynamical processes. Alternatively, the Nimbus Mg+ distributions may simply be a result of ion/neutral chemistry changes resulting from atmospheric changes and not dynamics. In such a case magnetic control would not dominate the distributions. Using in situ satellite measurements of metal ions from the Atmosphere Explorer satellites in the region above the main meteor layer and published sounding rocket measurements of the main metallic ion layers, the effects of the dynamics on the vertical content are delineated. The consequences of atmospheric changes on the vertical content are explored by separating the Nimbus measurements in a geodetic frame of reference.

  17. Semi-Interpenetrating Polymer Networks with Predefined Architecture for Metal Ion Fluorescence Monitoring

    Directory of Open Access Journals (Sweden)

    Kyriakos Christodoulou

    2016-11-01

    Full Text Available The development of new synthetic approaches for the preparation of efficient 3D luminescent chemosensors for transition metal ions receives considerable attention nowadays, owing to the key role of the latter as elements in biological systems and their harmful environmental effects when present in aquatic media. In this work, we describe an easy and versatile synthetic methodology that leads to the generation of nonconjugated 3D luminescent semi-interpenetrating amphiphilic networks (semi-IPN with structure-defined characteristics. More precisely, the synthesis involves the encapsulation of well-defined poly(9-anthrylmethyl methacrylate (pAnMMA (hydrophobic, luminescent linear polymer chains within a covalent poly(2-(dimethylaminoethyl methacrylate (pDMAEMA hydrophilic polymer network, derived via the 1,2-bis-(2-iodoethoxyethane (BIEE-induced crosslinking process of well-defined pDMAEMA linear chains. Characterization of their fluorescence properties demonstrated that these materials act as strong blue emitters when exposed to UV irradiation. This, combined with the presence of the metal-binding tertiary amino functionalities of the pDMAEMA segments, allowed for their applicability as sorbents and fluorescence chemosensors for transition metal ions (Fe3+, Cu2+ in solution via a chelation-enhanced fluorescence-quenching effect promoted within the semi-IPN network architecture. Ethylenediaminetetraacetic acid (EDTA-induced metal ion desorption and thus material recyclability has been also demonstrated.

  18. Detection of heavy metal ions in drinking water using a high-resolution differential surface plasmon resonance sensor.

    Science.gov (United States)

    Forzani, Erica S; Zhang, Haiqian; Chen, Wilfred; Tao, Nongjian

    2005-03-01

    We have built a high-resolution differential surface plasmon resonance (SPR) sensor for heavy metal ion detection. The sensor surface is divided into a reference and sensing areas, and the difference in the SPR angles from the two areas is detected with a quadrant cell photodetector as a differential signal. In the presence of metal ions, the differential signal changes due to specific binding of the metal ions onto the sensing area coated with properly selected peptides, which provides an accurate real-time measurement and quantification of the metal ions. Selective detection of Cu2+ and Ni2+ in the ppt-ppb range was achieved by coating the sensing surface with peptides NH2-Gly-Gly-His-COOH and NH2-(His)6-COOH. Cu2+ in drinking water was tested using this sensor.

  19. Versatile nature of hetero-chitosan based derivatives as biodegradable adsorbent for heavy metal ions; a review.

    Science.gov (United States)

    Ahmad, Mudasir; Manzoor, Kaiser; Ikram, Saiqa

    2017-12-01

    The polyfunctional chitosan can act as the biological macromolecule ligand not only for the adsorption and the recovery of metal ions from an aqueous media, but also for the fabrication of novel adsorbents which shows selectivity and better adsorption properties. The unmodified chitosan itself, a single cationic polysaccharide, has hydroxyl and amine groups carrying complex properties with the metal ions. In addition, the selectivity of metal ions, the adsorption efficiency and adsorption capacity of the adsorbent can be modified chemically. This review covers the synthetic strategies of chitosan towards the synthesis of hetero-chitosan based adsorbents via chemical modifications in past two decades. It also includes how chemical modification influences the metal adsorption with N, O, S and P containing chitosan derivatives. Hope this review article provides an opportunity for researchers in the future to explore the potential of chitosan as an adsorbent for removal of metal ions from wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. The mechanism of diffusion and ionic transport of alkali metal ions in the particles of tin(IV) antimonate

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; El-Absy, M.A.; Aly, S.I.; Atomic Energy Establishment, Cairo

    1992-01-01

    The kinetics of exchange Li + , Na + , K + and Cs + ions of tin(IV) antimonate with H + form was studied under particle-diffusion-control conditions at different temperatures. The value of activation energy, diffusion coefficient and entropy of activation increase with the ionic mobilities and radii, and decrease with the hydration energy of the alkali metal ions. On the basis of the kinetic parameters, the exchange of alkali metal ions occurs in the unhydrated form. (author). 29 refs.; 4 figs.; 2 tabs

  1. Estimation of Moisture Content & Metal Ions in White Flowers of Bougainvillea spectabilis and Purple Flowers of Bougainvillea glabra in Pakistan

    OpenAIRE

    *S. A. Rashid; F. S. Rehmani; 1M. Arman; M. Ibrahim; 2S. Shafique

    2011-01-01

    Bougainvillea consists of 18 shrubby species, growing in different parts of Pakistan and is being used as Anti-ulcer, Anti-diarrheal, Anti-microbial, Anti- diabetic, Amylase Inhibition and as for low blood pressure but none of the studies on Bougainvillea focused on the estimation of metal ion concentration. The focus of the present study was to estimation of moisture content and comparative analysis of trace metal ions in white flowers of Bougainvillea spectabilis Willd and Purple flowers of...

  2. Optimization of the Nonaqueous Capillary Electrophoresis Separation of Metal Ions Using Mixture Design and Response Surface Methods

    OpenAIRE

    DEMİR, Cevdet; YÜCEL, Yasin

    2014-01-01

    Mixture experimental design was used to enhance the separation selectivity of metal ions in nonaqueous capillary electrophoresis. The separation of cations (Ag, Fe, Cr, Mn, Cd, Co, Pb, Ni, Zn and Cu) was achieved using imidazole as UV co-ion for indirect detection. Acetic acid was chosen as an electrolyte because its cathodic electroosmotic flow permits faster separation. The composition of organic solvents is important to achieve the best separation of all metal ions. Simplex latt...

  3. The effect of platform switching on the levels of metal ion release from different implant–abutment couples

    Science.gov (United States)

    Alrabeah, Ghada O; Knowles, Jonathan C; Petridis, Haralampos

    2016-01-01

    The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (Pabutment size or connection (Pabutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples. PMID:27357323

  4. Adsorption performances and mechanisms of the newly synthesized N,N'-di (carboxymethyl) dithiocarbamate chelating resin toward divalent heavy metal ions from aqueous media

    International Nuclear Information System (INIS)

    Jing Xiaosheng; Liu Fuqiang; Yang Xin; Ling Panpan; Li Lanjuan; Long Chao; Li Aimin

    2009-01-01

    N,N'-di (carboxymethyl) dithiocarbamate chelating resin (PSDC) was synthesized by anchoring the chelating agent of N,N'-di (carboxymethyl) dithiocarbamate to the chloromethylated PS-DVB (Cl-PS-DVB) matrix, as a new adsorbent for removing divalent heavy metal ions from waste-stream. The physicochemical structures of Cl-PS-DVB and PSDC were elaborately characterized using Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and were further morphologically characterized using BET and BJH methods. The adsorption performances of PSDC towards heavy metals such as Cu(II), Pb(II) and Ni(II) were systematically investigated, based upon which the adsorption mechanisms were deeply exploited. For the above target, the classic batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal processes with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with Lagergren-second-order equation and Langmuir model respectively. The strong affinity of PSDC toward these target soft acids could be well demonstrated with the electrostatic attraction and chelating interaction caused by IDA moiety and sulphur which were namely soft bases on the concept of hard and soft acids and bases (HASB). Thermodynamic parameters, involving ΔH o , ΔS o and ΔG o were also calculated from graphical interpretation of the experimental data. The standard heats of adsorption (ΔH o ) were found to be endothermic and the entropy change values (ΔS o ) were calculated to be positive for the adsorption of Cu(II), Pb(II) and Ni(II) ions onto the tested adsorbents. Negative values of ΔG o indicated that adsorption processes for all tested metal ions onto PSDC were spontaneous.

  5. Architectural design criteria for f-block metal ion sequestering agents. 1998 annual progress report

    International Nuclear Information System (INIS)

    Dixon, D.A.; Hay, B.P.; Paine, R.T.; Raymond, K.N.; Rogers, R.D.; Roundhill, D.M.

    1998-01-01

    'The objective of this project is to provide a means to optimize ligand architecture for f-block metal recognition. The authors strategy builds on an innovative and successful molecular modeling approach in developing polyether ligand design criteria for the alkali and alkaline earth cations. The hypothesis underlying this proposal is that differences in metal ion binding with multidentate ligands bearing the same number and type of donor groups are primarily attributable to intramolecular steric factors. They propose quantifying these steric factors through the application of molecular mechanics models. The research involves close integration of theoretical and experimental chemistry. The experimental work entails synthesizing novel ligands and experimentally determining structures and binding constants for metal ion complexation by series of ligands in which architecture is systematically varied. The theoretical work entails using electronic structure calculations to parameterize a molecular mechanics force field for a range of metal ions and ligand types. The resulting molecular mechanics force field will be used to predict low energy structures for unidentate, bidentate, and multidentate ligands and their metal complexes through conformational searches. Results will be analyzed to assess the relative importance of several steric factors including optimal M-L length, optimal geometry at the metal center, optimal geometry at the donor atoms (complementarity), and conformation prior to binding (preorganization). An accurate set of criteria for the design of ligand architecture will be obtained from these results. These criteria will enable researchers to target ligand structures for synthesis and thereby dramatically reduce the time and cost associated with metal-specific ligand development.'

  6. Very broad beam metal ion source for large area ion implantation application

    International Nuclear Information System (INIS)

    Brown, I.; Anders, S.; Dickinson, M.R.; MacGill, R.A.; Yao, X.

    1993-01-01

    The authors have made and operated a very broad beam version of vacuum arc ion source and used it to carry out high energy metal ion implantation of a particularly large substrate. A multiple-cathode vacuum arc plasma source was coupled to a 50 cm diameter beam extractor (multiple aperture, accel-decel configuration) operated at a net extraction voltage of up to 50 kV. The metal ion species chosen were Ni and Ta. The mean ion charge state for Ni and Ta vacuum arc plasmas is 1.8 and 2.9, respectively, and so the mean ion energies were up to about 90 and 145 keV, respectively. The ion source was operated in a repetitively pulsed mode with pulse length 250 μs and repetition rate several pulses per second. The extracted beam had a gaussian profile with FWHM about 35 cm, giving a nominal beam area of about 1,000 cm 2 . The current of Ni or Ta metal ions in the beam was up to several amperes. The targets for the ion implantation were a number of 24-inch long, highly polished Cu rails from an electromagnetic rail gun. The rails were located about 80 cm away from the ion source extractor grids, and were moved across a diameter of the vessel in such a way as to maximize the uniformity of the implant along the rail. The saturation retained dose for Ta was limited to about 4 x 10 16 cm -2 because of the rather severe sputtering, in accordance with the theoretical expectations for these implantation conditions. Here they describe the ion source, the implantation procedure, and the kinds of implants that can be produced in this way

  7. Cardiac Light Chain Amyloidosis: The Role of Metal Ions in Oxidative Stress and Mitochondrial Damage.

    Science.gov (United States)

    Diomede, Luisa; Romeo, Margherita; Rognoni, Paola; Beeg, Marten; Foray, Claudia; Ghibaudi, Elena; Palladini, Giovanni; Cherny, Robert A; Verga, Laura; Capello, Gian Luca; Perfetti, Vittorio; Fiordaliso, Fabio; Merlini, Giampaolo; Salmona, Mario

    2017-09-20

    The knowledge of the mechanism underlying the cardiac damage in immunoglobulin light chain (LC) amyloidosis (AL) is essential to develop novel therapies and improve patients' outcome. Although an active role of reactive oxygen species (ROS) in LC-induced cardiotoxicity has already been envisaged, the actual mechanisms behind their generation remain elusive. This study was aimed at further dissecting the action of ROS generated by cardiotoxic LC in vivo and investigating whether transition metal ions are involved in this process. In the absence of reliable vertebrate model of AL, we used the nematode Caenorhabditis elegans, whose pharynx is an "ancestral heart." LC purified from patients with severe cardiac involvement intrinsically generated high levels of ROS and when administered to C. elegans induced ROS production, activation of the DAF-16/forkhead transcription factor (FOXO) pathway, and expression of proteins involved in stress resistance and survival. Profound functional and structural ROS-mediated mitochondrial damage, similar to that observed in amyloid-affected hearts from AL patients, was observed. All these effects were entirely dependent on the presence of metal ions since addition of metal chelator or metal-binding 8-hydroxyquinoline compounds (chelex, PBT2, and clioquinol) permanently blocked the ROS production and prevented the cardiotoxic effects of amyloid LC. Innovation and Conclusion: Our findings identify the key role of metal ions in driving the ROS-mediated toxic effects of LC. This is a novel conceptual advance that paves the way for new pharmacological strategies aimed at not only counteracting but also totally inhibiting the vicious cycle of redox damage. Antioxid. Redox Signal. 27, 567-582.

  8. Adsorption preference for divalent metal ions by Lactobacillus casei JCM1134.

    Science.gov (United States)

    Endo, Rin; Aoyagi, Hideki

    2018-05-09

    The removal of harmful metals from the intestinal environment can be inhibited by various ions which can interfere with the adsorption of target metal ions. Therefore, it is important to understand the ion selectivity and adsorption mechanism of the adsorbent. In this study, we estimated the adsorption properties of Lactobacillus casei JCM1134 by analyzing the correlation between its maximum adsorption level (q max ) for seven metals and their ion characteristics. Some metal ions showed altered adsorption levels by L. casei JCM1134 as culture growth time increased. Although it was impossible to identify specific adsorption components, adsorption of Sr and Ba may depend on capsular polysaccharide levels. The maximum adsorption of L. casei JCM1134 (9 h of growth in culture) for divalent metal ions was in the following order: Cu 2+  > Ba 2+  > Sr 2+  > Cd 2+  > Co 2+  > Mg 2+  > Ni 2+ . The q max showed a high positive correlation with the ionic radius. Because this tendency is similar to adsorption occurring through an ion exchange mechanism, it was inferred that an ion exchange mechanism contributed greatly to adsorption by L. casei JCM1134. Because the decrease in the amount of adsorption due to prolonged culture time was remarkable for metals with a large ion radius, it is likely that the adsorption components involved in the ion exchange mechanism decomposed over time. These results and analytical concept may be helpful for designing means to remove harmful metals from the intestinal tract.

  9. Bibliographies on radiation chemistry. 9. Metal ions and complexes. Part A: Cobalt, rhodium, iridium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, M Z; Ross, A B

    1986-01-01

    The one-electron oxidation and reduction of metal ions and complexes can yield species in unusual oxidation states, and ligand-radicals coordinated to the central metal. These often unstable species can be mechanistically important intermediates in thermal, photochemical, and electrochemical reactions involving metal-containing substances. Their generation via radiolysis provides an alternate means of characterizing them using kinetic and spectroscopic techniques. We hope these bibliographies on the radiation chemistry of metal ions and complexes, presented according to periodic groups, will prove useful to researchers in metallo-redox chemistry. These bibliographies contain only primary literature sources; reviews are not included. However, a list of general review articles on the radiation chemistry of metal ions and complexes is presented here in the first section which covers cobalt, rhodium and iridium, Group 9 in the new IUPAC notation. Additional parts of the bibliography are planned, covering other periodic groups. Part A of the bibliography was prepared by a search of the Radiation Chemistry Data Center Bibliographic Data Base (RCDCbib) through January 1986 for papers on rhodium, iridium and cobalt compounds, and radiolysis (both continuous and pulsed). Papers in which the use of metal compounds was incidental to the primary objective of the study were excluded. Excluded also were publications in unrefereed and obscure sources such as meeting proceedings, internal reports, dissertations, and patents. The majority of the studies in the resultant compilation deal with experiments performed on solutions, mainly aqueous, although a substantial fraction is devoted to solid-state esr measurements. The references are listed in separate sections for each of the metals, and are presented in approximate chronological order.

  10. Magnetite–hematite nanoparticles prepared by green methods for heavy metal ions removal from water

    International Nuclear Information System (INIS)

    Ahmed, M.A.; Ali, S.M.; El-Dek, S.I.; Galal, A.

    2013-01-01

    Graphical abstract: The negatively charged cubic magnetite nanoparticles, prepared by the coprecipitation method in N 2 atmosphere, can adsorb up to 99% of the positively charged toxic heavy metal ions at a proper pH value. -- Highlights: • Mixed magnetite–hematite nanoparticles were synthesized via different routes. • Prepared samples were characterized by XRD, HRTEM, BET and magnetic hysteresis. • The material was employed as a sorbent for removal of some heavy metal ions from water. • The effects of pH and the contact time on the adsorption process were studied and optimized. -- Abstract: Mixed magnetite–hematite nanoparticles were synthesized via different routes such as, coprecipitation in air and N 2 atmosphere, citrate–nitrate, glycine–nitrate and microwave-assisted citrate methods. The prepared samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), BET measurements and magnetic hysteresis. XRD data showed the formation of magnetite–hematite mixture with different compositions according to the synthesis method. The particle size was in the range of 4–52 nm for all the prepared samples. From HRTEM micrographs, it was found that, the synthesis method affects the moropholgy of the prepared samples in terms of crystallinity and porosity. The magnetite–hematite mixture was employed as a sorbent material for removal of some heavy metal ions from water such as lead(II), cadmium(II) and chromium(III). The effects of pH value and the contact time on the adsorption process were studied and optimized in order to obtain the highest possible adsorption efficiency of the magnetite–hematite mixture. The effect of the synthesis method of the magnetite–hematite mixture on the adsorption process was also investigated. It was found that samples prepared by the coprecipitation method had better adsorption efficiency than those prepared by other combustion methods

  11. The effect of magnetite nanoparticles synthesis conditions on their ability to separate heavy metal ions

    Directory of Open Access Journals (Sweden)

    Bobik Magdalena

    2017-06-01

    Full Text Available Magnetite nanoparticles have become a promising material for scientific research. Among numerous technologies of their synthesis, co-precipitation seems to be the most convenient, less time-consuming and cheap method which produces fine and pure iron oxide particles applicable to environmental issues. The aim of the work was to investigate how the co-precipitation synthesis parameters, such as temperature and base volume, influence the magnetite nanoparticles ability to separate heavy metal ions. The synthesis were conducted at nine combinations of different ammonia volumes - 8 cm3, 10 cm3, 15 cm3 and temperatures - 30°C, 60°C, 90°C for each ammonia volume. Iron oxides synthesized at each combination were examined as an adsorbent of seven heavy metals: Cr(VI, Pb(II, Cr(III, Cu(II, Zn(II, Ni(II and Cd(II. The representative sample of magnetite was characterized using XRD, SEM and BET methods. It was observed that more effective sorbent for majority of ions was produced at 30°C using 10 cm3 of ammonia. The characterization of the sample produced at these reaction conditions indicate that pure magnetite with an average crystallite size of 23.2 nm was obtained (XRD, the nanosized crystallites in the sample were agglomerated (SEM and the specific surface area of the aggregates was estimated to be 55.64 m2·g-1 (BET. The general conclusion of the work is the evidence that magnetite nanoparticles have the ability to adsorb heavy metal ions from the aqueous solutions. The effectiveness of the process depends on many factors such as kind of heavy metal ion or the synthesis parameters of the sorbent.

  12. Heavy metal ion adsorption behavior in nitrogen-doped magnetic carbon nanoparticles: Isotherms and kinetic study

    International Nuclear Information System (INIS)

    Shin, Keun-Young; Hong, Jin-Yong; Jang, Jyongsik

    2011-01-01

    Graphical abstract: Display Omitted Research highlights: → The monodisperse and multigram-scale N-MCNPs are fabricated by carbonization of polypyrrole as a carbon precursor. → The synthesized N-MCNPs provide an enhanced adsorption uptake for various heavy metal ions. → The N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. → The iron-impregnated N-MCNPs are reused up to 5 times with no loss of removal efficiency. - Abstract: To clarify the heavy metal adsorption mechanism of nitrogen-doped magnetic carbon nanoparticles (N-MCNPs), adsorption capacity was investigated from the adsorption isotherms, kinetics and thermodynamics points of view. The obtained results showed that the equilibrium adsorption behavior of Cr 3+ ion onto the N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. It indicated that the fabricated N-MCNPs had the homogenous surface for adsorption and all adsorption sites had equal adsorption energies. Furthermore, the adsorption onto N-MCNPs taken place through a chemical process involving the valence forces. According to the thermodynamics, the adsorption process is spontaneous and endothermic in nature which means that the adsorption capacity increases with increasing temperature due to the enhanced mobility of adsorbate molecules. The effects of the solution pH and the species of heavy metal ion on the adsorption uptake were also studied. The synthesized N-MCNPs exhibited an enhanced adsorption capacity for the heavy metal ions due to the high surface area and large amount of nitrogen contents.

  13. Electrochemical and visco metric studies on some copolymer/ homopolymer poly electrolytes and transition metal ion interaction

    International Nuclear Information System (INIS)

    Rajabi, F. H.; Frahani, B. V.

    2003-01-01

    Some random three-component copolymers have been prepared by condensing of formaldehyde with various aromatic amines. The compositions of the copolymers have been determined by known methods. selective complexation of copolymers have been carried out with PAA, PEI, PVP and some transition metal ions (e.g., Cu 2+ )by adding the components in various sequences. The relative complexation ability of different -NH 2 groups, associated with the various comonomer units, has been interpreted in terms of the these complexes has been studied by conductometry. potentiometry and viscometry techniques. A scheme has presented to explain the mode of interaction of the various components

  14. Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged Y zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sciyama, T; Arakawa, T; Matsuda, T; Yamazoe, N; Takita, Y

    1975-01-01

    The catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. The reaction products are nitrogen, nitrous oxide, and water in all cases. Selectivities to N/sub 2/ are 60 to 80% on all the cation exchanged zeolite catalysts exhibiting a relatively minor variation with the cationic species exchanged. The copper (II)-Y catalyst exhibits low temperature activity and has an unusual catalytic activity-temperature profile with a maximum at 120/sup 0/C. The catalytic activity is enhanced considerably when a second cation, especially cobalt (II) or iron (III) is coexchanged together with Cu (II) in Y zeolite.

  15. Divalent Metal Ions Induced Osteogenic Differentiation of MC3T3E1

    Science.gov (United States)

    Wang, Guoshou; Su, Wenta; Chen, Pohung; Huang, Teyang

    2017-12-01

    Biomaterial scaffolds blended with biochemical signal molecules with adequate osteoinductive and osteoconductive properties have attracted significant interest in bone tissue engineering regeneration. The divalent metal ions can gradually release from the scaffold into the culture medium and then induced osteoblastic differentiation of MC3T3E1. These MC3T3E1 cells expressed high activity of alkaline phosphatase, bone-related gene expression of collagen type I, Runx2, osteopontin, osteocalcin, and significantly enhanced deposited minerals on scaffold after 21 days of culture. This experiment provided a useful inducer for osteogenic differentiation in bone repair.

  16. Separation of strontium ions from other alkaline earth metal ions using masking reagent

    International Nuclear Information System (INIS)

    Komatsu, Y.

    1996-01-01

    Cs + and Sr 2+ have been well known as serious elements in high level radioactive waste. Separation of Cs + has already been successful when using an ion-exchange method from solution in the presence of other alkali metal ions. The separation of Sr 2+ is, however, not so easy by any known separation method such as solvent-extraction and ion-exchange methods. This is because Sr 2+ is in the middle of the selectivity series, which is Mg 2+ > Ca 2+ > Sr 2+ > Ba 2+ for the solvent-extraction method and Ba 2+ > Sr 2+ > Ca 2+ > Mg 2+ for the ion- exchange method. In the present study, separation of strontium from other alkaline earth metal ions was studied by a combined use of three types of separation methods at 298 K: the solvent-extraction method was applied for the first separation, in which thenoyltrifluoroacetone (TTA, extractant) and trioctylphosphine oxide ( TOPO, adduct forming ligand) were used for the organic phase of the system. The separation factors for each combination of four alkaline earth metal ions were determined by the values of the distribution ratio. The Mg 2+ was well separated from Sr 2+ by the TTA-TOPO system. However, the separation of the combinations of Ca 2+ -Sr 2+ and Sr 2+ -Ba 2+ was not complete by the above solvent-extraction system. The second separation method, an ion-exchange method was applied using dihydrogen tetratitanate hydrate fibers (H 2 Ti 4 O 9 nH 2 O) as an ion exchanger to separate Sr 2+ and Ba 2+ . The separation factors for each combination of four alkaline earth metal ions were calculated by the values of the distribution coefficients. Ba 2+ was well separated from Sr 2+ by the ion-exchange method. To separate Ca 2+ and Sr 2+ , however, a modified solvent-extraction method was finally used in which H 2 Ti 4 O 9 nH 2 O was used as a masking reagent of Sr 2+ . After the dihydrogen tetratitanate hydrate fibers were contacted with the aqueous solution containing Ca 2+ and Sr 2+ , the organic solution containing TTA and TOPO

  17. Removal of Cu(II) metal ions from aqueous solution by amine functionalized magnetic nanoparticles

    Science.gov (United States)

    Kothavale, V. P.; Karade, V. C.; Waifalkar, P. P.; Sahoo, Subasa C.; Patil, P. S.; Patil, P. B.

    2018-04-01

    The adsorption behavior of Cu(II) metal cations was investigated on the amine functionalized magnetic nanoparticles (MNPs). TheMNPs were synthesized by thesolvothermal method and functionalized with (3-Aminopropyl)triethoxysilane (APTES). MNPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM). The MNPs have pure magnetite phase with particle size around 10-12 nm. MNPs exhibits superparamagnetic behavior with asaturation magnetization of 68 emu/g. The maximum 38 % removal efficiency was obtained for Cu(II) metal ions from the aqueous solution.

  18. On matrix stabilisation of d- and f-transition metal ions in unstable oxidation states

    Energy Technology Data Exchange (ETDEWEB)

    Kiselev, Yurii M [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2009-01-31

    The state-of-the-art in matrix stabilisation of d- and f-transition metal ions in unstable oxidation states is analysed. Main aspects of this problem concerning the genealogy of appropriate matrix systems are classified. Relevant examples are given and the data that contradict the scheme proposed are discussed. The thermodynamics of the matrix stabilisation effect is considered using the concept of isomorphic miscibility. The influence of defects and non-equilibrium on the matrix stabilisation effect is discussed. The problem of identification of the oxidation states in matrix systems is examined and various types of matrix systems are considered.

  19. Application of Some Synthesized Polymeric Composite Resins for Removal of Some Metal Ions

    International Nuclear Information System (INIS)

    El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

    2005-01-01

    The ion-exchange and sorption characteristic of new polymeric composite resins, prepared by gamma radiation were experimentally studied. The composite resins shows high uptake for Co(II) and Eu(III) ions in aqueous solutions in wide range of ph. The selectivity of the resins to Co (II) or Eu (III) species in the presence of some competing ions and complexing agents (as Na + , Fe 3+ , EDTA Na 2 , etc.) was compared. Various factors that could affect the sorption behaviors of metal ions (Co (II) and Eu (III)) on the prepared polymeric composite resins were studied such as ionic strength, Contact time, volume mass ratio

  20. N-Dansyl-N`-ethylthiourea for the fluorometric detection of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, M.; Sandor, M. [Technische Univ. Muenchen, Garching (Germany). Anorganisch-Chemisches Inst.

    1996-11-01

    N-Dansyl-N`-ethylthiourea (DET) forms fluorescent chelates with a large number of heavy metal ions. The influence of the pH-value on the luminescence of DET and its metal chelates was investigated. The addition of Cu(II) to DET causes a bathochromic shift of the emission maximum, which is linearly dependent on the Cu(II) concentration. Low detection limits and a wide linear range of detection are achieved by HPLC using RP 18 columns as stationary phase. Also presented are first measurements of fluorescence decay times of the ligand as well as some complexes. (orig.) With 5 figs., 3 tabs.

  1. Dansyl - Substituted Aza Crown Ethers: Complexation with Alkali, Alkaline Earth Metal Ions and Ammonium

    Science.gov (United States)

    Deiab, Shihab; Archibong, Edikan; Tasheva, Donka; Mochona, Bereket; Gangapuram, Madhavi; Redda, Kinfe

    2011-01-01

    The present study investigates the binding properties of four dansyl substituted aza-crown ethers with alkali, alkaline earth metal ions and ammonium. The influence of the solvent polarity and protonation on the photophysical properties of the compounds was studied by UV/Vis and fluorescence methods. The host species caused only slight changes on the absorption spectra of the ligands. The fluorescence changes were more pronounced and concentration dependent thus allowing to calculate the binding constants of the process. The most stable complex under our working conditions was the one between Ba2+ and DNS18C6. PMID:21738561

  2. Nuclear quantum effects on adsorption of H2 and isotopologues on metal ions

    Science.gov (United States)

    Savchenko, Ievgeniia; Gu, Bing; Heine, Thomas; Jakowski, Jacek; Garashchuk, Sophya

    2017-02-01

    The nuclear quantum effects on the zero-point energy (ZPE), influencing adsorption of H2 and isotopologues on metal ions, are examined using normal mode analysis of ab initio electronic structure results for complexes with 17 metal cations. The lightest metallic nuclei, Li and Be, are found to be the most 'quantum'. The largest selectivity in adsorption is predicted for Cu, Ni and Co ions. Analysis of the nuclear wavepacket dynamics on the ground state electronic potential energy surfaces (PES) performed for complexes of Li+ and Cu+2 with H2/D2/HD shows that the PES anharmonicity changes the ZPE by up to 9%.

  3. On matrix stabilisation of d- and f-transition metal ions in unstable oxidation states

    International Nuclear Information System (INIS)

    Kiselev, Yurii M

    2009-01-01

    The state-of-the-art in matrix stabilisation of d- and f-transition metal ions in unstable oxidation states is analysed. Main aspects of this problem concerning the genealogy of appropriate matrix systems are classified. Relevant examples are given and the data that contradict the scheme proposed are discussed. The thermodynamics of the matrix stabilisation effect is considered using the concept of isomorphic miscibility. The influence of defects and non-equilibrium on the matrix stabilisation effect is discussed. The problem of identification of the oxidation states in matrix systems is examined and various types of matrix systems are considered.

  4. Ion conducting polymers and polymer blends for alkali metal ion batteries

    Science.gov (United States)

    DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Vitale, Alessandra

    2017-08-29

    Electrolyte compositions for batteries such as lithium ion and lithium air batteries are described. In some embodiments the compositions are liquid compositions comprising (a) a homogeneous solvent system, said solvent system comprising a perfluropolyether (PFPE) and polyethylene oxide (PEO); and (b) an alkali metal salt dissolved in said solvent system. In other embodiments the compositions are solid electrolyte compositions comprising: (a) a solid polymer, said polymer comprising a crosslinked product of a crosslinkable perfluropolyether (PFPE) and a crosslinkable polyethylene oxide (PEO); and (b) an alkali metal ion salt dissolved in said polymer. Batteries containing such compositions as electrolytes are also described.

  5. The main mechanisms of flotation extraction of heavy metal ions out of water solutions

    International Nuclear Information System (INIS)

    Zubareva, G.I.

    2002-01-01

    Flotation extraction of heavy metal ions out of water solutions using reagent EMKO (sodium soaps of vat residues of C grade) is presented. It is established that it is related to hydration energy and stability of sublates being formed. These two parameters affect contrariwise. A difference of molar ratios [EMKO]:[Me] in the course of extracting metals into froth can be explained by their different aggregative state, and a proportion of ionic form of metals and hydroxides being formed. Metal flotation rate is different for each of metal cations to be floated and is dependant on hydrogen ion concentrations [ru

  6. Metal ion extractant in microemulsions: where solvent extraction and surfactant science meet

    International Nuclear Information System (INIS)

    Bauer, C.

    2011-01-01

    The presented work describes the supramolecular structure of mixtures of a hydrophilic surfactant n-octyl-beta-glucoside (C8G1), and the hydrophobic metal ion extractant tributylphosphate (TBP) in n-dodecane/water as well as in the presence of salts. In the first part, basic solvent extraction system, composed of water, oil and extractant, will be introduced. The focus, however, lies on the extraction of multivalent metal ions from the aqueous phase. During this extraction process and in the following thermodynamic equilibrium, aggregation and phase transition in supramolecular assemblies occur, which are already described in literature. Notably, these reports rest on individual studies and specific conclusions, while a general concept is still missing. We therefore suggest the use of generalized phase diagrams to present the physico-chemical behaviour of (amphiphilic) extractant systems. These phase diagrams facilitated the development of a thermodynamic model based on molecular geometry and packing of the extractant molecules in the oil phase. As a result, we are now in the position to predict size and water content of extractant aggregates and, thus, verify the experimental results by calculation.Consequently, the second part presents a systematic study of the aqueous and organic phase of water/C8G1 and water/oil/TBP mixtures. The focus lies on understanding the interaction between metal ions and both amphiphilic molecules by means of small angle x-ray scattering (SAXS), dynamic light scattering (DLS) and UV-Vis spectroscopy. We confirmed the assumption that extraction of metal ions is driven by TBP, while C8G1 remains passive. In the third and last part, microemulsions of C8G1, TBP, water (and salt) and n-dodecane are characterized by small angle neutron scattering (SANS), and chemical analytics (Karl Fischer, total organic carbon, ICP-OES,...). The co-surfactant behaviour of TBP was highlighted by comparison to the classical n-alcohol (4≤n≤8) co

  7. Preparation and adsorption behavior for metal ions and humic acid of chitosan derivatives crosslinked by irradiation

    International Nuclear Information System (INIS)

    Zhao Long; Mitomo, H.; Yoshii, F.

    2006-01-01

    Introduction: Removing metal ions and humic acid from water in water treatment has attracted much environment and health interests. Adsorbents, derived from a nature polymer, are desired in the viewpoints of environment-conscious technologies. Recently, some nature materials such as chitin, chitosan and their derivatives have been identified as an attractive option due to their distinctive properties. For an insoluble adsorbent based on these polymers to be obtained over a broad pH range, modification through crosslinking is required. Crosslinking agents such as glutaric dialdehyde and ethylene glycol diglycidyl ether are frequently used for modification. However, these crosslinking agents are not preferred because of their physiological toxicity. Radiation-crosslinking without any additive in the fabrication process results in a high-purity product. In a previous work, we applied ionizing radiation to induce the crosslinking of carboxymethylchitosan under highly concentrated paste-like conditions. The aim of this study is to investigate the adsorption behavior of metal ions, humic acid on irradiation-crosslinked carboxymethylchitosan. Experimental: Irradiation of chitosan samples at paste-like state was done with an electron beam. The solubility test of these crosslinked materials were investigated in acidic, alkaline media, and some organic solvents. Swelling and charged characteristic analyses demonstrated typically pH-sensitive properties of these crosslinked materials. Scanning electron microscopic images showed that the crosslinked samples possessed porous morphological structure. The adsorption studies were carried out by the batch method at room temperature. Adsorption of heavy metal ions (such as Cu 2+ , Cd 2+ ) and humic acid onto crosslinked samples was found to be strongly pH-dependent. Adsorption kinetic studies indicated the rapid removal of metal ions, and humic acid from the aqueous solutions. Also, isothermal adsorption data revealed that Cu 2

  8. Development of an Electrochemical Metal-Ion Biosensor Using Self-Assembled Peptide Nanofibrils

    DEFF Research Database (Denmark)

    Viguier, Bruno; Zor, Kinga; Kasotakis, Emmanouil

    2011-01-01

    . These nanofibrils were obtained under aqueous conditions, at room temperature and outside the clean room. The functionalized gold electrode was evaluated by cyclic voltammetry, impedance spectroscopy, energy dispersive X-ray and atomic force microscopy. The obtained results displayed a layer of nanofibrils able......This article describes the combination of self-assembled peptide nanofibrils with metal electrodes for the development of an electrochemical metal-ion biosensor. The biological nanofibrils were immobilized on gold electrodes and used as biorecognition elements for the complexation with copper ions...

  9. A control on hydrophobic and hydrophilic interactions between HEWL and metal Schiff-base complexes comprising of different metal ions and ligands

    Energy Technology Data Exchange (ETDEWEB)

    Koley Seth, Banabithi; Ray, Aurkie; Basu, Samita, E-mail: samita.basu@saha.ac.in

    2015-05-15

    The structural effects of different copper(II) and nickel(II) Schiff base complexes on hen egg white lysozyme (HEWL) have been investigated through steady state and time resolved absorption and fluorescence, and circular dichroism spectroscopy. The Schiff base ligands with N{sub 4} donor atoms show both hydrophobic and hydrophilic interactions, however hydrophilic interaction prevails with ligands having N{sub 2}O{sub 2} donor atoms. Variation of metal ions from Cu{sup 2+} to Ni{sup 2+} with each type of Schiff base ligand increases the probability of hydrophilic over hydrophobic interactions, which supports their significance in regulating the binding affinity between HEWL and metal complexes. On photo-excitation the complexes comprising of Cu{sup 2+} ion instead of Ni{sup 2+} ion and ligands with N{sub 4} donor system rather than N{sub 2}O{sub 2} donor system, increases the probability of intersystem crossing to populate the corresponding triplet state as observed from laser flash photolysis study. The better binding affinity of nickel complexes with different selectivities compared to copper complexes towards HEWL emphasizes the potentiality of less explored nickel complexes in drug–protein interactions. - Highlights: • Ni{sup II} and Cu{sup II} -Schiff base complexes bind hen egg white lysozyme spontaneously. • Both hydrophobic and hydrophilic interactions are effective for N{sub 4} ligands. • For N{sub 2}O{sub 2} ligands the hydrophilic is predominant over hydrophobic interaction. • Binding affinity and selectivity of Ni{sup II}-complexes are better than Cu{sup II}-complexes. • Replacement of Cu{sup 2+} by Ni{sup 2+} in a ligand enhances chance of hydrophilic interaction.

  10. Reactions of metal ions and their clusters in the gas phase using laser ionization: ion cyclotron resonance spectroscopy

    International Nuclear Information System (INIS)

    Freiser, B.S.

    1981-04-01

    Two subjects are discussed in this report: advances in proposed studies on metal ion chemistry and expansion of laboratory facilities. The development of a combined pulsed laser source-ion cyclotron resonance spectrometer has proven to be a convenient and powerful method for generating metal ions and for studying their subsequent chemistry in the gas phase. The main emphasis of this research has been on the application of metal ions as a selective chemical ionization reagents and progress in this area are discussed. The goal is to identify trends in reactivity i.e. mechanisms useful in interpreting the chemical ionization spectra of unknown compounds and to test for the functional group selectivity of the various metal ions. The feasibility of these goals have been demonstrated in extensive studies on Cu + with esters and ketones, on Fe + with ethers, ketones, and hydrocarbons, and on Ti + with hydrocarbons. In addition, preliminary results on sulfur containing compounds and on a variety of other metallic ions have been obtained. Laboratory facilities were expanded from one ion cyclotron resonance (ICR) spectrometer to two, plus a third instrument the Fourier Transform Ion Cyclotron Resonance (FTICR) spectrometer

  11. The Cutting Edge of Affinity Electrophoresis Technology

    Science.gov (United States)

    Kinoshita, Eiji; Kinoshita-Kikuta, Emiko; Koike, Tohru

    2015-01-01

    Affinity electrophoresis is an important technique that is widely used to separate and analyze biomolecules in the fields of biology and medicine. Both quantitative and qualitative information can be gained through affinity electrophoresis. Affinity electrophoresis can be applied through a variety of strategies, such as mobility shift electrophoresis, charge shift electrophoresis or capillary affinity electrophoresis. These strategies are based on changes in the electrophoretic patterns of biological macromolecules that result from interactions or complex-formation processes that induce changes in the size or total charge of the molecules. Nucleic acid fragments can be characterized through their affinity to other molecules, for example transcriptional factor proteins. Hydrophobic membrane proteins can be identified by means of a shift in the mobility induced by a charged detergent. The various strategies have also been used in the estimation of association/disassociation constants. Some of these strategies have similarities to affinity chromatography, in that they use a probe or ligand immobilized on a supported matrix for electrophoresis. Such methods have recently contributed to profiling of major posttranslational modifications of proteins, such as glycosylation or phosphorylation. Here, we describe advances in analytical techniques involving affinity electrophoresis that have appeared during the last five years. PMID:28248262

  12. The Cutting Edge of Affinity Electrophoresis Technology.

    Science.gov (United States)

    Kinoshita, Eiji; Kinoshita-Kikuta, Emiko; Koike, Tohru

    2015-03-18

    Affinity electrophoresis is an important technique that is widely used to separate and analyze biomolecules in the fields of biology and medicine. Both quantitative and qualitative information can be gained through affinity electrophoresis. Affinity electrophoresis can be applied through a variety of strategies, such as mobility shift electrophoresis, charge shift electrophoresis or capillary affinity electrophoresis. These strategies are based on changes in the electrophoretic patterns of biological macromolecules that result from interactions or complex-formation processes that induce changes in the size or total charge of the molecules. Nucleic acid fragments can be characterized through their affinity to other molecules, for example transcriptional factor proteins. Hydrophobic membrane proteins can be identified by means of a shift in the mobility induced by a charged detergent. The various strategies have also been used in the estimation of association/disassociation constants. Some of these strategies have similarities to affinity chromatography, in that they use a probe or ligand immobilized on a supported matrix for electrophoresis. Such methods have recently contributed to profiling of major posttranslational modifications of proteins, such as glycosylation or phosphorylation. Here, we describe advances in analytical techniques involving affinity electrophoresis that have appeared during the last five years.

  13. Tracking metal ions with polypyrrole thin films adhesively bonded to diazonium-modified flexible ITO electrodes.

    Science.gov (United States)

    Lo, Momath; Diaw, Abdou K D; Gningue-Sall, Diariatou; Aaron, Jean-Jacques; Oturan, Mehmet A; Chehimi, Mohamed M

    2018-05-09

    Adhesively bonded polypyrrole thin films doped with benzene sulfonic acid (BSA) were electrodeposited on aminobenzenediazonium-modified flexible ITO electrodes and further employed for the detection of Pb 2+ , Cu 2+ , and Cd 2+ metal ions in aqueous medium. The aminophenyl (AP) adhesive layer was grafted to ITO by electroreduction of the in situ generated parent diazonium compound. Polypyrrole (PPy) thin films exhibited remarkable adhesion to aminophenyl (ITO-AP). The strongly adherent polypyrrole films exhibited excellent electroactivity in the doped state with BSA which itself served to chelate the metal ions in aqueous medium. The surface of the resulting, modified flexible electrode was characterized by XPS, SEM, and electrochemical methods. The ITO-AP-PPy electrodes were then used for the simultaneous detection of Cu 2+ , Cd 2+ , and Pb 2+ by differential pulse voltammetry (DPV). The detection limits were 11.1, 8.95, and 0.99 nM for Cu 2+ , Cd 2+ , and Pb 2+ , respectively. In addition, the modified electrodes displayed a good reproducibility, making them suitable for the determination of heavy metals in real wastewater samples.

  14. Improving Passivation Process of Si Nanocrystals Embedded in SiO2 Using Metal Ion Implantation

    Directory of Open Access Journals (Sweden)

    Jhovani Bornacelli

    2013-01-01

    Full Text Available We studied the photoluminescence (PL of Si nanocrystals (Si-NCs embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au, and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  15. Metal ions released from fixed orthodontic appliance affect hair mineral content.

    Science.gov (United States)

    Mikulewicz, Marcin; Wołowiec, Paulina; Loster, Bartłomiej; Chojnacka, Katarzyna

    2015-02-01

    The objective was to evaluate metal ion accumulation in hair of patients undergoing orthodontic treatment with fixed appliances in time. The patients (N = 47) participated in a questionnaire survey. Hair sampling was performed at the beginning and in the 4th, 8th, and 12th month of the treatment. The content of metals (Cr, Ni, Fe) in hair was analyzed by ICP-OES equipped with USN nebulizer. The peak release of Cr and Fe occurred after 4 months of the treatment, and the peak release of Ni gradually increased throughout the whole year of the therapy. During 1 year treatment, an average accumulation of metals in hair tissue was 7.42 ± 14.19 μg of Ni, 8.94 ± 13.1 μg of Cr, and 131 ± 279 μg of Fe. The mean content of Cr was higher than the 90th percentile value for this element. The upper limit of literature reference ranges for Cr, Ni, and Fe in hair was not exceeded. The value of exposure (kinetics and dose) of orthodontic patients to metal ions released from orthodontic appliances can be assessed by hair mineral analysis. The content of Cr was statistically significantly higher during the treatment than before the beginning of therapy.

  16. An Aqueous Metal-Ion Capacitor with Oxidized Carbon Nanotubes and Metallic Zinc Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Yuheng; Amal, Rose; Wang, Da-Wei, E-mail: da-wei.wang@unsw.edu.au [School of Chemical Engineering, The University of New South Wales (UNSW), Sydney, NSW (Australia)

    2016-10-03

    An aqueous metal ion capacitor comprising of a zinc anode, oxidized carbon nanotubes (oCNTs) cathode, and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn{sup 2+}, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC). The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy, and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm{sup −2} (corresponding to 53 F g{sup −1}) in the range of 0–1.8 V at 10 mV s{sup −1} and a stable cycling performance up to 5000 cycles.

  17. Simultaneous fluorescent detection of multiple metal ions based on the DNAzymes and graphene oxide.

    Science.gov (United States)

    Yun, Wen; Wu, Hong; Liu, Xingyan; Fu, Min; Jiang, Jiaolai; Du, Yunfeng; Yang, Lizhu; Huang, Yu

    2017-09-15

    A novel fluorescent detection strategy for simultaneous detection of Cu 2+ , Pb 2+ and Mg 2+ based on DNAzyme branched junction structure with three kinds of DNAzymes and graphene oxide (GO) was presented. Three fluorophores labeled DNA sequences consisted with enzyme-strand (E-DNA) and substrate strand (S-DNA) were annealed to form DNAzyme branched junction structure. In the presence of target metal ion, the DNAzyme was activated to cleave the fluorophore labeled S-DNA. The S-DNA fragments were released and adsorbed onto GO surface to quench the fluorescent signal. The detection limit was calculated to be 1 nM for Cu 2+ , 200 nM for Mg 2+ , and 0.3 nM for Pb 2+ , respectively. This strategy was successfully used for simultaneous detection of Cu 2+ , Mg 2+ and Pb 2+ in human serum. Moreover, it had potential application for simultaneous detection of multiple metal ions in environmental and biological samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Polymeric supported sorbents for decreasing hazardous metal ions content in wet process phosphoric acid

    International Nuclear Information System (INIS)

    El-Zahhar, A.A.; El-Naggar, H.A.; Ahmed, M.

    2005-01-01

    Procedure for preparation of polymeric supported silica, and their usage for decreasing hazardous metal ion content in wet process phosphoric acid was developed. The procedure is based firstly on extraction silica from rice straw by alkaline treatment , secondly supporting the produced silica on binding polyacrylonitrile (PAN). The produced polymer based sorbent was used for decreasing hazardous metal ions (especially iron) present as inorganic impurities in crud Egyptian phosphoric acid (green acid). Different factors affecting the sorption equilibrium ( contact time, temperature , sorbent mass and batch factor ) were studied. Studying the sorption isotherm revealed that the adsorption data could favorably fit the Langmuir adsorption isotherm. In the dynamic study , the sorption capacity at (Cξ/Cο = 50%) was found to be 28.5 mg/g and the loaded column could be regenerated using 50ml of 0.15 M HNO 3 . The regenerated column could undergo sorption regeneration cycles up to four cycles without significant decrease in the sorption capacity , weight loss or change in the physical properties of the sorbent

  19. Supplementation of soft drinks with metallic ions reduces dissolution of bovine enamel

    Directory of Open Access Journals (Sweden)

    Heloisa Aparecida Barbosa da Silva Pereira

    2013-07-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the effect of the addition of metallic ions to carbonated drinks on their erosive potential. MATERIAL AND METHODS: Powdered enamel was added to carbonated beverages (Coca-ColaTM or Sprite ZeroTM and shaken for 30 s. The samples were then immediately centrifuged and the supernatant removed. This procedure was repeated 5 times with the beverages containing Cu2+, Mg2+, Mn2+ or Zn2+ (1.25-60 mmol/L. For Coca-ColaTM, the concentration of each ion that exhibited the highest protection was also evaluated in combination with Fe2+. The phosphate or calcium released were analyzed spectrophotometrically. Data were analyzed using ANOVA and Tukey's test (p<0.05. RESULTS: For Coca-ColaTM, the best protective effect was observed for Zn2+ alone (10 mmol/L or in combination (1 mmol/L with other ions (12% and 27%, respectively, when compared with the control. Regarding Sprite ZeroTM, the best protective effect was observed for Cu2+ at 15 and 30 mmol/L, which decreased the dissolution by 22-23%. Zn2+ at 2.5 mmol/L also reduced the dissolution of powdered enamel by 8%. CONCLUSIONS: The results suggest that the combination of metallic ions can be an alternative to reduce the erosive potential of Coca-ColaTM. Regarding Sprite ZeroTM, the addition of Cu2+ seems to be the best alternative.

  20. Preparation of metal ion exchange resin by radiation-induced graft copolymerization

    International Nuclear Information System (INIS)

    Nakase, Yoshiaki; Akasaka, Nobuhiro.

    1982-06-01

    Radiation-induced graft copolymerization of 2-acrylamide-2-methyl propane sulfonic acid (AMPS) onto polyvinylchloride (PVC) and polyvinylidene chloride resin (PVD) was investigated in the water-acetone system and their adsorptive activities to metal ion were also examined. In the case of PVC, the degree of grafting increased with the increase of acetone content, but the adsorptive activity to metal ions (mainly lithic ion) became maximum in the system with water/acetone of 2/3. Grafted PVC prepared at about 35 0 C and at a higher concentration of AMPS showed higher adsorption activity than the other cases. In the case of PVD, a similar result was obtained with the case of PVC except the temperature dependence and effect of swelling agent. Polymerizations at temperatures of 35 and 50 0 C showed no effect on the degree of grafting, and the usage of a swelling agent was quite effective to the adsorptive activity. Glass transition temperature of the grafted copolymer was the same as that of original polymer, and their thermal stability was confirmed up to the temperature at which homopolymer of AMPS decomposed, about 180 0 C. (author)

  1. Urease from Staphylococcus saprophyticus. Some properties and inhibition by metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Glemzha, A A; Kovzan, V B; Yuodval' kite, D Yu

    1984-12-01

    Data concerning the molecular weight, the dependence of the enzymic rate of the pH and the concentration of the substrate, and the effect of metal ions on urease activity are presented and discussed. Precipitation with ethanol was used to isolate a urease preparation with a specific activity of 250-300 units/mg of protein from Staphylococcus saprophyticus cells. The molecular weight of the enzyme, determined by gel filtration on a Sephadex G-200 column is 250,000. Maximum activity of St. saprophyticus urease occurred at pH 6.8-7.0; the K/sub m/ value, at 30/sup 0/C (pH 6.8) equalled 7.36 x 10/sup -3/ M, V/sub max/ is 1.5 ..mu..mol NH/sub 3//min. The enzyme was reversibly inhibited by heavy metal ions. The sequence of inhibiting effect of the ions studied is: Ag/sup +/>Ni/sup 2 +/>Cd/sup 2 +/>Co/sup 2 +/>Hg/sup 2 +/>Cu/sup 2 +/>Zn/sup 2 +/>Pb/sup 2 +/ and pK of groups of the active center equal 5.0-5.25 and 8.25 and are near in value to those of the imidazole ring of histidine (0.5-7.0) and the Sh-group of cysteine (8.3-8.6). 19 references, 4 figures.

  2. Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Fazli Wahid

    2017-11-01

    Full Text Available Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag, gold (Au, zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO2 and magnesium oxide (MgO have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

  3. BIOSORBENTS – PROSPECTIVE MATERIALS FOR HEAVY METAL IONS EXTRACTION FROM WASTEWATER

    Directory of Open Access Journals (Sweden)

    О. Kovalenko

    2018-04-01

    Full Text Available The article deals with ecological safety, resource saving, economic efficienty in the technologies of wastewater purification from heavy metals ions. It is shown that modern technologies of wastewater purification from such substances need to be improved. А promising way to solve this problem is the production and wide use of carbon sorbents obtained from the waste of processing agricultural raw materials and waste generated at food enterprises. Scientific research is actively carried out in this area. This is due to the possibility of organizing the process of wastewater purification from heavy metal ions in a cheap and effective way. The development of biosorbent production is relevant for Ukraine, as the development of agriculture and food industry is of primary importance. The article presents the results of an analytical review of literary sources on various aspects of the scientific problem. In particular, possible sources of raw materials for the production of biosorbents, classical and modified technologies for their production, mechanisms of biosorption using raw materials with different chemical composition, sorption characteristics of biosorbents, and indicators of the economic efficiency of their production are considered.

  4. An Aqueous Metal-ion Capacitor with Oxidised Carbon Nanotubes and Metallic Zinc Electrodes

    Directory of Open Access Journals (Sweden)

    Yuheng Tian

    2016-10-01

    Full Text Available An aqueous metal ion capacitor comprising of a zinc anode, an oxidized carbon nanotubes (oCNTs cathode and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn2+, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC. The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm-2 (corresponding to 53 F g-1 in the range of 0-1.8 V at 10 mV s-1 and a stable cycling performance up to 5000 cycles.

  5. Designing antimicrobial bioactive glass materials with embedded metal ions synthesized by the sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Palza, Humberto, E-mail: hpalza@ing.uchile.cl [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile); Escobar, Blanca; Bejarano, Julian [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile); Bravo, Denisse [Departamento de Patología, Facultad de Odontología, Universidad de Chile, Santiago (Chile); Diaz-Dosque, Mario [Departamento de Ciencias Básicas y Comunitarias, Facultad de Odontología, Universidad de Chile, Santiago (Chile); Perez, Javier [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile)

    2013-10-15

    Bioactive glasses (SiO{sub 2}–P{sub 2}O{sub 5}–CaO) having tailored concentrations of different biocide metal ions (copper or silver) were produced by the sol–gel method. All the particles release phosphorous ions when immersed in water and simulated body fluid (SBF). Moreover, a surface layer of polycrystalline hydroxy-carbonate apatite was formed on the particle surfaces after 10 day immersion in SBF as confirmed by X-ray diffraction and scanning electron microscopy (SEM) showing the bioactive materials. Samples with embedded either copper or silver ions were able to further release the biocide ions with a release rate that depends on the metal embedded and the dissolution medium: water or SBF. This biocide ion release from the samples explains the antimicrobial effect of our active particles against Escherichia coli DH5α ampicillin-resistant (Gram-negative) and Streptococcus mutans (Gram-positive) as determined by the Minimum Bactericidal Concentration (MBC) method. The antimicrobial behavior of the particles depends on the bacteria and the biocide ion used. Noteworthy, although samples with copper are able to release more metal ion than samples with silver, they present higher MBC showing the high effect of silver against these bacteria. - Highlights: • Copper and silver act as antimicrobial additives in bioactive glass materials. • Silver is more toxic than copper ions in these bioactive materials. • Sol–gel method allows the synthesis of antimicrobial bioactive materials.

  6. Designing antimicrobial bioactive glass materials with embedded metal ions synthesized by the sol–gel method

    International Nuclear Information System (INIS)

    Palza, Humberto; Escobar, Blanca; Bejarano, Julian; Bravo, Denisse; Diaz-Dosque, Mario; Perez, Javier

    2013-01-01

    Bioactive glasses (SiO 2 –P 2 O 5 –CaO) having tailored concentrations of different biocide metal ions (copper or silver) were produced by the sol–gel method. All the particles release phosphorous ions when immersed in water and simulated body fluid (SBF). Moreover, a surface layer of polycrystalline hydroxy-carbonate apatite was formed on the particle surfaces after 10 day immersion in SBF as confirmed by X-ray diffraction and scanning electron microscopy (SEM) showing the bioactive materials. Samples with embedded either copper or silver ions were able to further release the biocide ions with a release rate that depends on the metal embedded and the dissolution medium: water or SBF. This biocide ion release from the samples explains the antimicrobial effect of our active particles against Escherichia coli DH5α ampicillin-resistant (Gram-negative) and Streptococcus mutans (Gram-positive) as determined by the Minimum Bactericidal Concentration (MBC) method. The antimicrobial behavior of the particles depends on the bacteria and the biocide ion used. Noteworthy, although samples with copper are able to release more metal ion than samples with silver, they present higher MBC showing the high effect of silver against these bacteria. - Highlights: • Copper and silver act as antimicrobial additives in bioactive glass materials. • Silver is more toxic than copper ions in these bioactive materials. • Sol–gel method allows the synthesis of antimicrobial bioactive materials

  7. The study on the ion exchange behavior of metal ions using composite ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kukki; Lee, Kunjai [Nuclear Engineering Department Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Youngkyun [Korea Institute of Nuclear Safety, Daejon (Korea, Republic of); Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2002-04-15

    In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated.

  8. Oxidative damage to collagen and related substrates by metal ion/hydrogen peroxide systems

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1997-01-01

    . In this study electron paramagnetic resonance spectroscopy with spin trapping has been used to identify radicals formed on collagen and related materials by metal ion-H2O2 mixtures. Attack of the hydroxyl radical, from a Fe(II)-H2O2 redox couple, on collagen peptides gave signals from both side chain (.CHR...... are similar to those from the alpha-carbon site of peptides and the side-chain of lysine. Enzymatic digestion of the large, protein-derived, species releases similar low-molecular-weight adducts. The metal ion employed has a dramatic effect on the species observed. With Cu(I)-H2O2 or Cu(II)-H2O2 instead of Fe(II)-H......2O2, evidence has been obtained for: i) altered sites of attack and fragmentation, ii) C-terminal decarboxylation, and iii) hydrogen abstraction at N-terminal alpha-carbon sites. This altered behaviour is believed to be due to the binding of copper ions to some substrates and hence site...

  9. Redox Active Transition Metal ions Make Melanin Susceptible to Chemical Degradation Induced by Organic Peroxide.

    Science.gov (United States)

    Zadlo, Andrzej; Pilat, Anna; Sarna, Michal; Pawlak, Anna; Sarna, Tadeusz

    2017-12-01

    With aging, retinal pigment epithelium melanosomes, by fusion with the age pigment lipofuscin, form complex granules called melanolipofuscin. Lipofuscin granules may contain oxidized proteins and lipid hydroperoxides, which in melanolipofuscin could chemically modify melanin polymer, while transition metal ions present in melanin can accelerate such oxidative modifications. The aim of this research was to examine the effect of selected transition metal ions on melanin susceptibility to chemical modification induced by the water-soluble tert-butyl hydroperoxide used as an oxidizing agent. Synthetic melanin obtained by DOPA autooxidation and melanosomes isolated from bovine retinal pigment epithelium were analyzed. To monitor tert-butyl hydroperoxide-induced oxidative changes of DMa and BMs, electron paramagnetic resonance spectroscopy, UV-vis absorption spectroscopy, dynamic light scattering, atomic force microscopy and electron paramagnetic resonance oximetry were employed. These measurements revealed that both copper and iron ions accelerated chemical degradation induced by tert-butyl hydroperoxide, while zinc ions had no effect. Strong prooxidant action was detected only in the case of melanosomes and melanin degraded in the presence of iron. It can be postulated that similar chemical processes, if they occur in situ in melanolipofuscin granules of the human retinal pigment epithelium, would modify antioxidant properties of melanin and its reactivity.

  10. Formation of Negative Metal Ions in a Field-Free Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, E

    1969-02-15

    A field-free and homogeneous plasma of a large volume is formed by neutron irradiation of {sup 3}He at a density corresponding to NTP and at gas temperatures in the range 300-1600 deg K. The accuracy and ease by which the source density of free electrons can be varied and controlled offers special possibilities to study recombination and attachment phenomena in the absence of diffusion. These possibilities are described and utilized for the study of the effects of mixing the helium gas with metal vapours. Attachment of electrons to neutral metal atoms is found to be the dominant cause of electron removal for metal concentrations above certain limits. Negative metal ions are formed and the rate of their formation was determined to be about 10{sup -13} cm{sup 3}/s. Evidence is also presented, that for such conditions where formation of negative metal ions does not occur, the electrons are lost in electron-ion recombinations, in which the third body is not an electron. No molecular helium spectrum is observed from the plasma when it is very close to spectroscopic purity. Instead, between 3,000-7,000 A only one atomic helium line at 5875 A is observed. The recombination of He{sup +}{sub 2} may therefore be dissociative. A difference in recombination behaviour between {sup 3}He and {sup 4}He at high pressures may therefore exist considering results from previous work on {sup 4}He.

  11. Chitin nanofibrils for rapid and efficient removal of metal ions from water system.

    Science.gov (United States)

    Liu, Dagang; Zhu, Yi; Li, Zehui; Tian, Donglin; Chen, Lei; Chen, Peng

    2013-10-15

    Joint mechanical defibrillation was successfully used to downsize chitin micro-particles (CMP) into nanofibrils without changing its chemical or crystalline structure. The fine chitin nanofibrils (CNF) bearing width of about 50 nm and length of more than 1 μm were then developed as heavy metal ion sorbents. The uptake performance of CNF dependent on pH, ionic concentration, time, and temperature was investigated. Results show that fixation amount of Cd(II), Ni(II), Cu(II), Zn(II), Pb(II), Cr(III) on CNF was up to 2.94, 2.30, 2.22, 2.06, 1.46, and 0.31 mmol/g, respectively, much higher than CMP due to high specific surface area and widely distributed pores of CNF. Adsorption kinetics of CMP and CNF followed pseudo-second-order model and Freundlich isotherm although CNF exhibited higher rate constant and sorption capacity than that of CMP. The defibrillated CNF is renewable, feasible, easily recyclable, and is thought as good candidate for heavy metal ion treatment due to their low sorption energy, rapid and efficient uptake capacity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Sulfide precipitation method of separating uranium from Group II and Group III metal ions

    International Nuclear Information System (INIS)

    Sundar, P.S.

    1977-01-01

    Uranium is separated from analytical Group II and Group III metal ions in an aqueous liquor containing uranyl ions. The liquor is extracted with a non-interfering, water-immiscible, organic solvent containing a reagent which will react with the uranyl ions to form a complex soluble in the solvent. If the liquor is acidic, the solvent is washed with water. Then to the solvent is added an aqueous solution containing about 0.5 to 1.0 mole per liter of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions and sufficient sulfide ions to precipitate the metal ions as sulfides. The solvent and the aqueous solution are separated and the sulfides filtered from the aqueous solution. The ammonium-uranyl-tricarbonate in the aqueous solution can then be precipitated by increasing the concentration of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions to about 1.5 to 2.5 moles per liter. The precipitate is filtered and calcined to obtain U 3 O 8 or UO 2 . 21 claims, 1 figure

  13. Solvent extraction of some metal ions by dithiocarbamate types of chemically modified lipophilic chitosan

    International Nuclear Information System (INIS)

    Inoue, K.; Nakagawa, H.; Naganawa, H.; Tachimori, S.

    2001-01-01

    Chitosan is a basic polysaccharide containing primary amino groups with high reactivity. we prepared O,O'-decanoyl chitosan and dithiocarbamate O,O'-decanoyl chitosan; the former was soluble in chloroform and toluene, while latter was soluble not only these diluents but also in some aliphatic diluents such as hexane and kerosene which are employed in commercial scale solvent extraction. Solvent extraction by dithiocarbamate O,O'-decanoyl chitosan in kerosene was tested for some base metal ions from sulfuric acid solution. The sequence of selectivity for these metal ions was found to be as follows: Cu(II) >> Ni(II) > Cd(II) ∼ Fe(III) > Co(II) ∼ Zn(II). Copper(II) was quantitatively extracted at pH > 1 and quantitatively stripped with 2 M sulfuric acid solution. Solvent extraction of silver(I) and gold(III) from hydrochloric acid as well as lanthanides and americium(III) from nitrate solution were also tested. Americium was selectively extracted over trivalent lanthanides, suggesting a high possibility for the final treatment of high level radioactive wastes. (authors)

  14. Formation of Negative Metal Ions in a Field-Free Plasma

    International Nuclear Information System (INIS)

    Larsson, E.

    1969-02-01

    A field-free and homogeneous plasma of a large volume is formed by neutron irradiation of 3 He at a density corresponding to NTP and at gas temperatures in the range 300-1600 deg K. The accuracy and ease by which the source density of free electrons can be varied and controlled offers special possibilities to study recombination and attachment phenomena in the absence of diffusion. These possibilities are described and utilized for the study of the effects of mixing the helium gas with metal vapours. Attachment of electrons to neutral metal atoms is found to be the dominant cause of electron removal for metal concentrations above certain limits. Negative metal ions are formed and the rate of their formation was determined to be about 10 -13 cm 3 /s. Evidence is also presented, that for such conditions where formation of negative metal ions does not occur, the electrons are lost in electron-ion recombinations, in which the third body is not an electron. No molecular helium spectrum is observed from the plasma when it is very close to spectroscopic purity. Instead, between 3,000-7,000 A only one atomic helium line at 5875 A is observed. The recombination of He + 2 may therefore be dissociative. A difference in recombination behaviour between 3 He and 4 He at high pressures may therefore exist considering results from previous work on 4 He

  15. The role of metallic ions in nano-bio hybrid catalysts from ab initio first principles

    Science.gov (United States)

    Behera, Sushant; Deb, Pritam

    We employ high-accuracy linear-scaling density functional theory calculations with a near-complete basis set and a minimal parameter implicit solvent model, within the self-consistent calculation, on silver ion assimilated on bacteriorhodopsin (bR) at specific binding sites. The geometry optimization indicates the formation of stable active sites at the interface of nano-bio hybrid and density of states reflects the metallic behavior of the active sites. Detailed kinetics of the catalytic reaction is revealed using ab initio electronic structure calculations. We observed that the metal ion incorporated active sites are more efficient in electrolytic splitting of water than pristine sites due to their less value of Gibbs free energy for hydrogen evolution reaction and strong synergistic effect. The volcano plot analysis and free energy diagram are considered to understan hydrogen evolution efficiency. Moreover, the essential role of metallic ion on catalytic efficiency is elucidated. DBT, Government of India, vide Grant No BT/357/NE/TBP/ 2012. DST, GoI for financial support under INSPIRE Fellowship(IF150325).

  16. UV-radiation curing of simultaneous interpenetrating polymer network hydrogels for enhanced heavy metal ion removal

    International Nuclear Information System (INIS)

    Wang, Jingjing; Liu, Fang

    2012-01-01

    Highlights: ► Simultaneous IPN hydrogels were prepared by hybrid photopolymerization of AM and DVE-3. ► The synergistic complexation was found in the adsorption studies. ► The simultaneous IPN hydrogels could be used as fast-responsive and renewable sorbent materials. - Abstract: Simultaneous interpenetrating polymer network (IPN) hydrogels have been prepared by UV-initiated polymerization of a mixture of acrylamide (AM) and triethylene glycol divinyl ether (DVE-3). The consumption of each monomer upon UV-irradiation was monitored in situ by real-time infrared (RTIR) spectroscopy. The acrylamide monomer AM was shown to polymerize faster and more extensively than the vinyl ether monomer DVE-3, which was further consumed upon storage of the sample in the dark, due to the living character of the cationic polymerization. The IPN hydrogels were used to remove heavy metal ions from aqueous solution under the non-competitive condition. The effects of pH values of the feed solution and the DVE-3 content in the formulation on the adsorption capacity were investigated. The results indicated that the adsorption capacity of the IPN hydrogels increased with the pH values and DVE-3 content in the formulation. Furthermore, the synergistic complexation of metal ions with two polymer networks in the IPN was found in the adsorption studies. Adsorption kinetics and regeneration studies suggested that the IPN hydrogels could be used as fast-responsive and renewable sorbent materials in heavy metal removing processes.

  17. The study on the ion exchange behavior of metal ions using composite ion exchange resin

    International Nuclear Information System (INIS)

    Kim, Kukki; Lee, Kunjai; Kim, Youngkyun; Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun

    2002-01-01

    In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated

  18. Effect of detergents, trypsin, and bivalent metal ions on interfacial activation and functioning of phospholipase D.

    Science.gov (United States)

    Madyarov, Sh R

    2014-07-01

    The effects of detergents, trypsin, and bivalent metal ions on production of phosphatidic and lysophosphatidic acids by the action of phospholipase D (PLD) on lecithin and lysolecithin were studied. It was found that these reaction products and dodecyl sulfate ions activate PLD, whereas other anionic detergents are less effective. A protective effect of the functioning enzyme against its hydrolytic inactivation by trypsin was found. Bivalent metal ions can be arranged in the following sequence by their ability to activate PLD in the hydrolysis of lecithin and lysolecithin: Ca2+>Sr2+>Ba2+>Mg2+. These results are considered in relation to a proposed mechanism of activation and functioning of PLD with the participation of clusters of phosphatidates and lysophosphatidates. Such Me2+-induced formation of rafts or microdomains from the products of hydrolysis of phospholipids can rationalize not only PLD activation and self-regulation, but also the action of this mechanism on other components and properties of biomembranes. PLD and other lipolytic enzymes can be classified as lateral vector enzymes.

  19. Effective adsorption of oil droplets from oil-in-water emulsion using metal ions encapsulated biopolymers: Role of metal ions and their mechanism in oil removal.

    Science.gov (United States)

    Elanchezhiyan, S Sd; Prabhu, Subbaiah Muthu; Meenakshi, Sankaran

    2018-06-01

    Herein, synthesized and compared the three different kinds of hybrid bio-polymeric composites viz., lanthanum embedded chitosan/gelatin (La@CS-GEL), zirconium embedded chitosan/gelatin (Zr@CS-GEL) and cerium embedded chitosan/gelatin (Ce@CS-GEL) in terms of their oil uptake efficiency. The adsorption efficiency was studied under various optimized parameters like contact time, pH, dose, initial oil concentration and temperature. The oil adsorption capacity was found to be 91, 82 and 45% for La@CS-GEL, Zr@CS-GEL and Ce@CS-GEL composites respectively. The metals were used as a bridging material to connect both CS and GEL using the hydrophilic groups to enhance the oil recovery by hydrophobic interaction. Also, the introduction of metal ions on the surface of biopolymers would modify the oil/water properties which in turn, decrease the interfacial tension between oil and water phases. The mechanism of oil uptake was explained using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), energy dispersive X-ray (EDAX) and heat of combustion. The experimental data confirmed Langmuir isotherm as the best fit for oil adsorption process. Thermodynamic parameters such as standard free energy (ΔG°), standard enthalpy (ΔH°) and standard entropy (ΔS°) indicated that the oil adsorption was spontaneous and endothermic. The oil adsorption mechanism was established based on isotherm and thermodynamic models. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Development of a four-zone carousel process packed with metal ion-imprinted polymer for continuous separation of copper ions from manganese ions, cobalt ions, and the constituent metal ions of the buffer solution used as eluent.

    Science.gov (United States)

    Jo, Se-Hee; Park, Chanhun; Yi, Sung Chul; Kim, Dukjoon; Mun, Sungyong

    2011-08-19

    A three-zone carousel process, in which Cu(II)-imprinted polymer (Cu-MIP) and a buffer solution were employed as adsorbent and eluent respectively, has been developed previously for continuous separation of Cu²⁺ (product) from Mn²⁺ and Co²⁺ (impurities). Although this process was reported to be successful in the aforementioned separation task, the way of using a buffer solution as eluent made it inevitable that the product stream included the buffer-related metal ions (i.e., the constituent metal ions of the buffer solution) as well as copper ions. For a more perfect recovery of copper ions, it would be necessary to improve the previous carousel process such that it can remove the buffer-related metal ions from copper ions while maintaining the previous function of separating copper ions from the other 2 impure heavy-metal ions. This improvement was made in this study by proposing a four-zone carousel process based on the following strategy: (1) the addition of one more zone for performing the two-step re-equilibration tasks and (2) the use of water as the eluent of the washing step in the separation zone. The operating conditions of such a proposed process were determined on the basis of the data from a series of single-column experiments. Under the determined operating conditions, 3 runs of carousel experiments were carried out. The results of these experiments revealed that the feed-loading time was a key parameter affecting the performance of the proposed process. Consequently, the continuous separation of copper ions from both the impure heavy-metal ions and the buffer-related metal ions could be achieved with a purity of 91.9% and a yield of 92.8% by using the proposed carousel process based on a properly chosen feed-loading time. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Characteristics of a continuous denitration by formic acid - electrolytic trimming of residual acid with accompanying the precipitation of metal ions

    International Nuclear Information System (INIS)

    Kim, G. W.; Kim, S. H.; Lim, J. G.; Lee, I. H.

    2003-01-01

    This work has studied the characteristics of destruction of nitric acid and precipitation of several metal ions in a continuous denitration process combining a denitration by formic acid and a residual acid-electrolytic trimming system. The metal ions of Zr, Mo, Fe, and Nd did not affect the electrodes at the step of electrolytic trimming of the residual acid after denitration by formic acid. The Mo ion in electrolytic solution enhanced the generation of nitrite ion during the electrolytic reaction. The mole ratio of formic acid to nitric acid fed into the continuous denitration reactor using formic acid affected much the final acidity, the precipitation yields of metal ions, the precipitate morphology. At the ratio of 1.65, the process had the lowest final acidity of less than 0.1 M, and the precipitation yields of Zr and Mo reached 95% and 83%, respectively as the highest values

  2. Molecular electron affinities

    International Nuclear Information System (INIS)

    Fukuda, E.K.

    1983-01-01

    Molecular electron affinities have historically been difficult quantities to measure accurately. These difficulties arise from differences in structure between the ion and neutral as well as the existence of excited negative ion states. To circumvent these problems, relative electron affinities were determined in this dissertation by studying equilibrium electron transfer reactions using a pulsed ion cyclotron resonance (ICR) spectrometer. Direct measurement of ion and neutral concentrations for reactions of the general type, A - + B = B - + A, allow calculation of the equilibrium constant and, therefore, the free energy change. The free energy difference is related to the difference in electron affinities between A and B. A relative electron affinity scale covering a range of about 45 kcal/mol was constructed with various substituted p-benzoquinones, nitrobenzenes, anhydrides, and benzophenones. To assign absolute electron affinities, various species with accurately known electron affinities are tied to the scale via ion-cyclotron double resonance bracketing techniques. After the relative scale is anchored to these species with well-known electron affinities, the scale is then used as a check on other electron affinity values as well as generating new electron affinity values. Many discrepancies were found between the electron affinities measured using the ICR technique and previous literature determinations

  3. Effect of organic acids produced by penicillium notatum on the extraction of metals ions from brown shale

    International Nuclear Information System (INIS)

    Bhatti, H.N.; Sarwar, S.; Ilyas, S.

    2012-01-01

    Preset study was undertaken to check the bio leaching feasibility of brown shale with Penicillium notatum by using different carbon sources. Large quantities of the metal ions are embodied in shales that can be recovered. Presently available techniques (pyrometallurgical and hydrometallurgical) are expensive or may have a negative impact on the environment. Penicillium notatum exhibited a good potential in generating varieties of organic acids effective for metal ions solubilization. Maximum leaching of Cu (91.55 %) and Mg (79.83 %) was obtained with glucose as substrate while maximum recovery of Mn (71.46 %) was obtained in medium having molasses as substrate. (author)

  4. Unambiguously identifying spin states of transition-metal ions in the Earth (Invited)

    Science.gov (United States)

    Hsu, H.

    2010-12-01

    The spin state of a transition-metal ion in crystalline solids, defined by the number of unpaired electrons in the ion’s incomplete 3d shell, may vary with many factors, such as temperature, pressure, strain, and the local atomic configuration, to name a few. Such a phenomenon, known as spin-state crossover, plays a crucial role in spintronic materials. Recently, the pressure-induced spin-state crossover in iron-bearing minerals has been recognized to affect the minerals’ structural and elastic properties. However, the detailed mechanism of such crossover in iron-bearing magnesium silicate perovskite, the most abundant mineral in the Earth, remains unclear. A significant part of this confusion arises from the difficulty in reliably extracting the spin state from experiments. For the same reason, the thermally-induced spin-state crossover in lanthanum cobaltite (LaCoO3) has been controversial for more than four decades. In this talk, I will discuss how first-principle calculations can help clarifying these long-standing controversies. In addition to the total energy, equation of state, and elastic properties of each spin state, first-principle calculations also predict the electric field gradient (EFG) at the nucleus of each transition-metal ion. Our calculations showed that the nuclear EFG, a quantity that can be measured via Mössbauer or nuclear magnetic resonance (NMR) spectroscopy, depends primarily on the spin state, irrespective of the concentration or configuration of transition-metal ions. Such robustness makes EFG a unique fingerprint to identify the spin state. The combination of first-principle calculations and Mössbauer/NMR spectroscopy can therefore be a reliable and efficient approach in tackling spin-state crossover problems in the Earth. This work was primarily supported by the MRSEC Program of NSF under Awards Number DMR-0212302 and DMR-0819885, and partially supported by NSF under ATM-0428774 (V-Lab), EAR-1019853, and EAR-0810272. The

  5. Dansyl-naphthalimide dyads as molecular probes: effect of spacer group on metal ion binding properties.

    Science.gov (United States)

    Shankar, Balaraman H; Ramaiah, Danaboyina

    2011-11-17

    Interaction of a few dansyl-naphthalimide conjugates 1a-e linked through polymethylene spacer groups with various metal ions was investigated through absorption, fluorescence, NMR, isothermal calorimetric (ITC), and laser flash photolysis techniques. The characteristic feature of these dyads is that they exhibit competing singlet-singlet energy transfer (SSET) and photoinduced electron transfer (PET) processes, both of which decrease with the increase in spacer length. Depending on the spacer group, these dyads interact selectively with divalent Cu(2+) and Zn(2+) ions, as compared to other mono- and divalent metal ions. Jobs plot analysis showed that these dyads form 2:3 complexes with Cu(2+) ions, while 1:1 complexes were observed with Zn(2+) ions. The association constants for the Zn(2+) and Cu(2+) complexes were determined and are found to be in the order 10(3)-10(5) M(-1). Irrespective of the length of the spacer group, these dyads interestingly act as fluorescence ratiometric molecular probes for Cu(2+) ions by altering the emission intensity of both dansyl and naphthalimide chromophores. In contrast, only the fluorescence intensity of the naphthalimide chromophore of the lower homologues (n = 1-3) was altered by Zn(2+) ions. (1)H NMR and ITC measurements confirmed the involvement of both sulfonamide and dimethylamine groups in the complexation with Cu(2+) ions, while only the latter group was involved with Zn(2+) ions. Laser excitation of the dyads 1a-e showed formation of a transient absorption which can be attributed to the radical cation of the naphthalimide chromophore, whereas only the triplet excited state of the dyads 1a-e was observed in the presence of Cu(2+) ions. Uniquely, the complexation of 1a-e with Cu(2+) ions affects both PET and SSET processes, while only the PET process was partially inhibited by Zn(2+) ions in the lower homologues (n = 1-3) and the higher homologues exhibited negligible changes in their emission properties. Our results

  6. Major signal suppression from metal ion clusters in SFC/ESI-MS - Cause and effects.

    Science.gov (United States)

    Haglind, Alfred; Hedeland, Mikael; Arvidsson, Torbjörn; Pettersson, Curt E

    2018-05-01

    The widening application area of SFC-MS with polar analytes and water-containing samples facilitates the use of quick and simple sample preparation techniques such as "dilute and shoot" and protein precipitation. This has also introduced new polar interfering components such as alkali metal ions naturally abundant in e.g. blood plasma and urine, which have shown to be retained using screening conditions in SFC/ESI-TOF-MS and causing areas of major ion suppression. Analytes co-eluting with these clusters will have a decreased signal intensity, which might have a major effect on both quantification and identification. When investigating the composition of the alkali metal clusters using accurate mass and isotopic pattern, it could be concluded that they were previously not described in the literature. Using NaCl and KCl standards and different chromatographic conditions, varying e.g. column and modifier, the clusters proved to be formed from the alkali metal ions in combination with the alcohol modifier and make-up solvent. Their compositions were [(XOCH 3 ) n  + X] + , [(XOH) n  + X] + , [(X 2 CO 3 ) n  + X] + and [(XOOCOCH 3 ) n  + X] + for X = Na + or K + in ESI+. In ESI-, the clusters depended more on modifier, with [(XCl) n  + Cl] - and [(XOCH 3 ) n  + OCH 3 ] - mainly formed in pure methanol and [(XOOCH) n  + OOCH] - when 20 mM NH 4 Fa was added. To prevent the formation of the clusters by avoiding methanol as modifier might be difficult, as this is a widely used modifier providing good solubility when analyzing polar compounds in SFC. A sample preparation with e.g. LLE would remove the alkali ions, however also introducing a time consuming and discriminating step into the method. Since the alkali metal ions were retained and affected by chromatographic adjustments as e.g. mobile phase modifications, a way to avoid them could therefore be chromatographic tuning, when analyzing samples containing them. Copyright © 2018 Elsevier

  7. Novel 6xHis tagged foot-and-mouth disease virus vaccine bound to nanolipoprotein adjuvant via metal ions provides antigenic distinction and effective protective immunity

    International Nuclear Information System (INIS)

    Rai, Devendra K.; Segundo, Fayna Diaz-San; Schafer, Elizabeth; Burrage, Thomas G.; Rodriguez, Luis L.; Santos, Teresa de los; Hoeprich, Paul D.; Rieder, Elizabeth

    2016-01-01

    Here, we engineered two FMD viruses with histidine residues inserted into or fused to the FMDV capsid. Both 6xHis viruses exhibited growth kinetics, plaque morphologies and antigenic characteristics similar to wild-type virus. The 6xHis tag allowed one-step purification of the mutant virions by Co"2"+ affinity columns. Electron microscopy and biochemical assays showed that the 6xHis FMDVs readily assembled into antigen: adjuvant complexes in solution, by conjugating with Ni"2"+-chelated nanolipoprotein and monophosphoryl lipid A adjuvant (MPLA:NiNLP). Animals Immunized with the inactivated 6xHis-FMDV:MPLA:NiNLP vaccine acquired enhanced protective immunity against FMDV challenge compared to virions alone. Induction of anti-6xHis and anti-FMDV neutralizing antibodies in the immunized animals could be exploited in the differentiation of vaccinated from infected animals needed for the improvement of FMD control measures. The novel marker vaccine/nanolipid technology described here has broad applications for the development of distinctive and effective immune responses to other pathogens of importance. - Highlights: • 6xHis-tags in A_2_4 FMDV enable purification and biding to adjuvants via metal ions. • 6xHis A_2_4 FMDV:MPLA:NiNLP vaccine enhanced protective immunity against FMDV. • Surface exposed capsid tags allow distinction of infected from vaccinated animals.

  8. Novel 6xHis tagged foot-and-mouth disease virus vaccine bound to nanolipoprotein adjuvant via metal ions provides antigenic distinction and effective protective immunity

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Devendra K.; Segundo, Fayna Diaz-San [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Department of Pathobiology and Veterinary Science, CANR, University of Connecticut, Storrs, CT 06269 (United States); Schafer, Elizabeth [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Burrage, Thomas G. [Department of Homeland Security, S & T, Targeted Advance Development, Virus, Cellular and Molecular Imaging Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Rodriguez, Luis L.; Santos, Teresa de los [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Hoeprich, Paul D. [Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA (United States); Rieder, Elizabeth, E-mail: Elizabeth.Rieder@ars.usda.gov [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States)

    2016-08-15

    Here, we engineered two FMD viruses with histidine residues inserted into or fused to the FMDV capsid. Both 6xHis viruses exhibited growth kinetics, plaque morphologies and antigenic characteristics similar to wild-type virus. The 6xHis tag allowed one-step purification of the mutant virions by Co{sup 2+} affinity columns. Electron microscopy and biochemical assays showed that the 6xHis FMDVs readily assembled into antigen: adjuvant complexes in solution, by conjugating with Ni{sup 2+}-chelated nanolipoprotein and monophosphoryl lipid A adjuvant (MPLA:NiNLP). Animals Immunized with the inactivated 6xHis-FMDV:MPLA:NiNLP vaccine acquired enhanced protective immunity against FMDV challenge compared to virions alone. Induction of anti-6xHis and anti-FMDV neutralizing antibodies in the immunized animals could be exploited in the differentiation of vaccinated from infected animals needed for the improvement of FMD control measures. The novel marker vaccine/nanolipid technology described here has broad applications for the development of distinctive and effective immune responses to other pathogens of importance. - Highlights: • 6xHis-tags in A{sub 24} FMDV enable purification and biding to adjuvants via metal ions. • 6xHis A{sub 24} FMDV:MPLA:NiNLP vaccine enhanced protective immunity against FMDV. • Surface exposed capsid tags allow distinction of infected from vaccinated animals.

  9. Tethering metal ions to photocatalyst particulate surfaces by bifunctional molecular linkers for efficient hydrogen evolution

    KAUST Repository

    Yu, Weili

    2014-08-19

    A simple and versatile method for the preparation of photocatalyst particulates modified with effective cocatalysts is presented; the method involves the sequential soaking of photocatalyst particulates in solutions containing bifunctional organic linkers and metal ions. The modification of the particulate surfaces is a universal and reproducible method because the molecular linkers utilize strong covalent bonds, which in turn result in modified monolayer with a small but controlled quantity of metals. The photocatalysis results indicated that the CdS with likely photochemically reduced Pd and Ni, which were initially immobilized via ethanedithiol (EDT) as a linker, were highly efficient for photocatalytic hydrogen evolution from Na2S-Na2SO3-containing aqueous solutions. The method developed in this study opens a new synthesis route for the preparation of effective photocatalysts with various combinations of bifunctional linkers, metals, and photocatalyst particulate materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Catalytic activity of γ-irradiated transition metal ions in the decomposition of hydrogen peroxide

    International Nuclear Information System (INIS)

    Arnikar, H.J.; Kapadi, A.H.; Gohad, A.S.; Bhosale, S.B.

    1988-01-01

    The catalystic decomposition of hydrogen peroxide by transition metal ions, Fe 2+ , Fe 3+ , Co 2+ and Cu 2+ , adsorbed on neutral α-alumina was studied over the temperature range of 295-313 K. γ-irradiation of the catalysts to a dose of 0.12 MGy enhanced markedly the first order decomposition rate. Negligible in the case of Cu 2+ , the radiation effect increased roughly in the order of the number of unpaired d electrons in these ions: Cu(II), Fe(II), Co(II) and Fe(III). Results are explained on the basis of Kremer's mechanism of electron induced heterogeneous decomposition of H 2 O 2 . The radiation effect is attributed to the initial excess of electrons released from traps in the beginning of the reaction

  11. Means for obtaining a metal ion beam from a heavy-ion cyclotron source

    Science.gov (United States)

    Hudson, E.D.; Mallory, M.L.

    1975-08-01

    A description is given of a modification to a cyclotron ion source used in producing a high intensity metal ion beam. A small amount of an inert support gas maintains the usual plasma arc, except that it is necessary for the support gas to have a heavy mass, e.g., xenon or krypton as opposed to neon. A plate, fabricated from the metal (or anything that can be sputtered) to be ionized, is mounted on the back wall of the ion source arc chamber and is bombarded by returning energetic low-charged gas ions that fail to cross the initial accelerating gap between the ion source and the accelerating electrode. Some of the atoms that are dislodged from the plate by the returning gas ions become ionized and are extracted as a useful beam of heavy ions. (auth)

  12. Influence of implantation of three metallic ions on the mechanical properties of two polymers

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.V. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Perry, A.J. [Australian National Univ., Canberra, ACT (Australia); Treglio, J.R.

    1996-12-31

    Ion implantation of poly ethylene terephthalate (PET) and polystyrene (PS) with various high energy metallic ions at 70 kV to dose of 3 x 10{sup 16} ions/cm 2 have been made. Measurements of the mechanical properties of the polymers before and after implantation have been made with an ultra microindentation system using both pointed and a small (2 nm) radiused spherical tipped indenter. Significant differences have been observed between the Ti-B dual implanted surfaces and those of the Au and W implanted surfaces. For both the PET and PS the resistance to indenter penetration at very low loads was much greater for the Ti-B dual implanted surfaces. The estimated hardness and modulus versus depth of penetration for both indenters shows that the spherical indenter produces more consistent and less controversial values that are somewhat lower than the optimistic estimates from pointed indenters. 8 refs., 2 fig.

  13. Influence of implantation of three metallic ions on the mechanical properties of two polymers

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M V [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Perry, A J [Australian National Univ., Canberra, ACT (Australia); Treglio, J R

    1997-12-31

    Ion implantation of poly ethylene terephthalate (PET) and polystyrene (PS) with various high energy metallic ions at 70 kV to dose of 3 x 10{sup 16} ions/cm 2 have been made. Measurements of the mechanical properties of the polymers before and after implantation have been made with an ultra microindentation system using both pointed and a small (2 nm) radiused spherical tipped indenter. Significant differences have been observed between the Ti-B dual implanted surfaces and those of the Au and W implanted surfaces. For both the PET and PS the resistance to indenter penetration at very low loads was much greater for the Ti-B dual implanted surfaces. The estimated hardness and modulus versus depth of penetration for both indenters shows that the spherical indenter produces more consistent and less controversial values that are somewhat lower than the optimistic estimates from pointed indenters. 8 refs., 2 fig.

  14. Tethering metal ions to photocatalyst particulate surfaces by bifunctional molecular linkers for efficient hydrogen evolution

    KAUST Repository

    Yu, Weili; Isimjan, Tayirjan T.; Del Gobbo, Silvano; Anjum, Dalaver Hussain; Abdel-Azeim, Safwat; Cavallo, Luigi; Garcia Esparza, Angel T.; Domen, Kazunari; Xu, Wei; Takanabe, Kazuhiro

    2014-01-01

    A simple and versatile method for the preparation of photocatalyst particulates modified with effective cocatalysts is presented; the method involves the sequential soaking of photocatalyst particulates in solutions containing bifunctional organic linkers and metal ions. The modification of the particulate surfaces is a universal and reproducible method because the molecular linkers utilize strong covalent bonds, which in turn result in modified monolayer with a small but controlled quantity of metals. The photocatalysis results indicated that the CdS with likely photochemically reduced Pd and Ni, which were initially immobilized via ethanedithiol (EDT) as a linker, were highly efficient for photocatalytic hydrogen evolution from Na2S-Na2SO3-containing aqueous solutions. The method developed in this study opens a new synthesis route for the preparation of effective photocatalysts with various combinations of bifunctional linkers, metals, and photocatalyst particulate materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Evaluation of metal ions in rice samples: extraction and direct determination by ICP OES

    International Nuclear Information System (INIS)

    Oliveira, Andrea; Cadore, Solange; Baccan, Nivaldo

    2012-01-01

    A method for extraction of metal ions present in rice samples using ammoniacal EDTA solution, pH = 10, as extractor agent is proposed under the following optimized conditions: 0.20 g of rice sample and 5.00 mL of ammoniacal EDTA (ethylenediaminetetraacetic acid) solution, with 5 min of ultrasound exposure time. Using robust ICP OES (inductively coupled plasma atomic emission spectrometry) conditions, direct analysis of the extraction solution was allowed, and the recovery values obtained were above 90% for most of the studied elements (P, K, Mg, Ca, Zn, Mn, Cu and Mo) with RSD -1 (Mn) - 48.68 mg kg -1 (K), showing adequate detectability for the determination of the analytes. The analysis of different samples indicated that Brazilian 'integral' rice contains higher contents of the constituents studied, followed by 'parboiled' rice, and the 'agulhinha' rice a long and thin grain type. (author)

  16. Nuclear quantum effects on adsorption of H_2 and isotopologues on metal ions

    International Nuclear Information System (INIS)

    Savchenko, Ievgeniia; Gu, Bing; Heine, Thomas; Jakowski, Jacek; Garashchuk, Sophya

    2017-01-01

    The nuclear quantum effects on the zero-point energy (ZPE), influencing adsorption of H_2 and isotopologues on metal ions, are examined in this study using normal mode analysis of ab initio electronic structure results for complexes with 17 metal cations. To estimate for the anharmonicity, a nuclear wavepacket dynamics on the ground state electronic potential energy surfaces (PES) have been employed for complexes of Li"+ and Cu"+"2 with H_2, D_2, HD. The dynamics analysis shows that incorporation of the PES anharmonicity changes the ZPE by up to 9%. Finally, the lightest metallic nuclei, Li and Be, are found to be the most 'quantum'. The largest selectivity in adsorption is predicted for Cu, Ni and Co ions.

  17. Observation of self-sputtering in energetic condensation of metal ions

    International Nuclear Information System (INIS)

    Anders, Andre

    2004-01-01

    The condensation of energetic metal ions on a surface may cause self-sputtering even in the absence of substrate bias. Charge-state-averaged self-sputtering yields were determined for both zirconium and gold ions generated by a cathodic vacuum arc. Films were deposited on differently biased substrates exposed to streaming Zr and Au vacuum arc plasma. The self-sputtering yields for both metals were estimated to be about 0.05 in the absence of bias, and exceeding 0.5 when bias reached-50 V. These surprisingly high values can be reconciled with binary collision theory and molecular dynamics calculations taking high the kinetic and potential energy of vacuum arc ions into account

  18. Extraction of metal ions using chemically modified silica gel: a PIXE analysis.

    Science.gov (United States)

    Jal, P K; Dutta, R K; Sudarshan, M; Saha, A; Bhattacharyya, S N; Chintalapudi, S N; K Mishra, B

    2001-08-30

    Organic ligand with carboxyhydrazide functional group was immobilised on the surface of silica gel and the metal binding capacity of the ligand-embedded silica was investigated. The functional group was covalently bonded to the silica matrix through a spacer of methylene groups by sequential reactions of silica gel with dibromobutane, malonic ester and hydrazine in different media. Surface area value of the modified silica was determined. The changes in surface area were correlated with the structural change of the silica surface due to chemical modifications. A mixture solution of metal ions [K(I),Cr(III),Co(II),Ni(II),Cu(II),Zn(II),Hg(II) and U(VI)] was treated with the ligand-embedded silica in 10(-3) M aqueous solution. The measurement of metal extraction capacity of the silica based ligand was done by multielemental analysis of the metal complexes thus formed by using Proton Induced X-ray Emission (PIXE) technique.

  19. Preparation of stable alginate microcapsules coated with chitosan or polyethyleneimine for extraction of heavy metal ions.

    Science.gov (United States)

    Outokesh, Mohammad; Mimura, Hitoshi; Niibori, Yuichi; Tanaka, Kouichi

    2006-05-01

    Stable alginate microcapsules in dried form containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (HA) were prepared by coating of fresh alginate microcapsules with chitosan or polyethyleneimine (PEI). The thickness of coatings was estimated by electron probe microanalysis (EPMA), along with electron microscopy (SEM), as well as comparison of uptake percentage of coated and uncoated hollow capsules. Characterization of microcapsules was carried out by Ag(+) uptake experiments, destructive chemical analyses and thermogravimetric methods (TG and DTA). Chemical stability tests in HNO(3) and NaNO(3) media indicated that the coating with 4-double layer chitosan or mono-layer PEI led to an appreciable enhancement of impermeability in the range of pH > 1 or [Na(+)] microcapsules nearly completely hold their extractant content. Stable extractive microcapsules have an appreciable potential for the selective removal of heavy metal ions.

  20. Role of metal ions in the cognitive decline of Down syndrome

    Directory of Open Access Journals (Sweden)

    Nakisa eMalakooti

    2014-06-01

    Full Text Available Down syndrome (DS, caused by trisomy of whole or part of chromosome 21 is the most common mental impairment. All Down syndrome (DS individuals suffer from cognitive decline and develop Alzheimer’s disease (AD by the age of forty. The appearance of enlarged early endosomes, followed by Amyloid β peptide deposition, the appearance of tau-containing neurofibrillary tangles and basal forebrain cholinergic neuron (BFCN degeneration are the neuropathological characteristics of this disease. In this review we will examine the role of metal ion dyshomeostasis and the genes which may be involved in these processes, and relate these back to the manifestation of age-dependant cognitive decline in DS.

  1. Oxidation of sulfur (IV by oxygen in aqueous solution: role of some metal ions

    Directory of Open Access Journals (Sweden)

    Martins Claudia R.

    1999-01-01

    Full Text Available Catalytic effect of metal ions: Cr(VI, Cr(III, Cd(II, V(V and chloride anion, on the oxidation of S(IV in aqueous solution, at concentrations of metal ions and S(IV usually found in urban atmospheres, were studied under controlled experimental conditions (pH (2.1 - 4,5, T (25.0 - 35.0 °C, air flow rate, concentration of reactants, etc.... The kinetic constant determined at 25.0 °C and pH range (2.1 - 4.5, using ultra pure water was 8.0 ± 0.5 x 10-4 s-1. This value was considered as a reference for the oxidation reaction rate. The kinetic constants determined in the presence of Cr(VI revealed that the oxidation reaction of S(IV is quite influenced by the acidity. At pH = 2.1 (K = 2.3 x 10-2 mg-1 L s-1 the reaction is carried out with a rate five times greater when compared to pH = 2.6 (K = 4.3 x 10-3 mg-1 L s-1 and thirty times greater when compared to pH = 3.4 (K= 8.0 x 10 -4 mg-1 L s-1. The following rate expression was obtained at pH = 2.6: -r(S(IV =K [Cr(VI] [S(IV] and the activation energy found was: Ea =70.3KJ/mol. No catalytic effects were observed for Cd(II or chloride ion, while inhibitory effects were observed for Cr(III and V(V ions.

  2. Change of microstructure of clays due to the presence of heavy metal ions in pore water

    Directory of Open Access Journals (Sweden)

    Saiyouri N.

    2010-06-01

    Full Text Available The compressibility of engineered barrier clays is, to a large extent, controlled by microstructure change due to the presence of chemical ions in clay-water system. This paper aims to investigate the change of microstructure of clays due to the presence of heavy metal ions in pore water. We use two pure clays (kaolinite and bentonite in the study. One-dimensional consolidation tests were performed on reconstituted samples, which are prepared with distilled water and three types of heavy metal solutions (Pb(NO32, Cu(NO32, Zn(NO32,. In order to better understand the impact of chemical pore fluid on microstructure of the two clays, following the consolidation test, scanning electron microscope (SEM observations and mercury intrusion pore size distribution measurements (MIP were conducted. Due to the measurement range of MIP, which is only allowed to measure the minimal pore size 20 Å, BET method by gas sorption, whose measurement pore size range is from 3.5 Å to 500 Å, is used to measure the micropore size distribution. By this method, specific surface area of the soils can be also determined. It can be employed to demonstrate the difference of creep performance between the soils. Furthermore, a series of batch equilibrium tests were conducted to better understand the physical-chemical interactions between the particles of soils and the heavy metal ions. With the further consideration of the interparticle electrical attractive and repulsive force, an attempt has been made to predict the creep behaviour by using the modified Gouy-Chapman double layer theory. The results of calculation were compared with that of tests. The comparison shows that the prediction of compressibility of the clays according to the modified double diffuse layer theory can be reasonably agreement with the experimental data.

  3. Electron paramagnetic resonance studies on conformation states and metal ion exchange properties of vanadium bromoperoxidase

    International Nuclear Information System (INIS)

    de Boer, E.; Boon, K.; Wever, R.

    1988-01-01

    An electron paramagnetic resonance (EPR) study was carried out to examine structural aspects of vanadium-containing bromoperoxidase from the brown seaweed Ascophyllum nodosum. At high pH, the reduced form of bromoperoxidase showed an apparently axially symmetric EPR signal with 16 hyperfine lines. When the pH was lowered, a new EPR spectrum was formed. When EPR spectra of the reduced enzyme were recorded in the pH range from 4.2 to 8.4, it appeared that these changes were linked to a functional group with an apparent pK/sub a/ of about 5.4. In D 2 O this value for the pK/sub a/ was 5.3. It is suggested that these effects arise from protonation of histidine or aspartate/glutamate residues near the metal ion. The values for the isotropic hyperfine coupling constant of the reduced enzyme at both high and low pH are also consistent with a ligand field containing nitrogen and/or oxygen donor atoms. When reduced bromoperoxidase was dissolved in D 2 O or H 2 17 O instead of H 2 16 O, vanadium (IV) hyperfine line widths were markedly affected, demonstrating that water is a ligand of the metal ion. Together with previous work these findings suggest that vanadium (IV) is not involved in catalytic turnover and confirm the model in which the vanadium (V) ion of the native enzyme only serves to bind both hydrogen peroxide and bromide. After excess vanadate was added to a homogeneous preparation of purified bromoperoxidase, the extent of vanadium bound to the protein increased from 0.5 to 1.1, with a concomitant enhancement of enzymic activity. Finally, it is demonstrated that both vanadate (VO 4 3- ) and molybdate (MoO 4 2- ) compete for the same site on apobromoperoxidase

  4. High charge state metal ion production in vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1994-01-01

    The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

  5. In Vitro Antioxidant versus Metal Ion Chelating Properties of Flavonoids: A Structure-Activity Investigation

    Science.gov (United States)

    Cherrak, Sabri Ahmed; Mokhtari-Soulimane, Nassima; Berroukeche, Farid; Bensenane, Bachir; Cherbonnel, Angéline; Merzouk, Hafida; Elhabiri, Mourad

    2016-01-01

    Natural flavonoids such as quercetin, (+)catechin and rutin as well as four methoxylated derivatives of quercetin used as models were investigated to elucidate their impact on the oxidant and antioxidant status of human red blood cells (RBCs). The impact of these compounds against metal toxicity was studied as well as their antiradical activities with DPPH assay. Antihemolytic experiments were conducted on quercetin, (+)catechin and rutin with excess of Fe, Cu and Zn (400 μM), and the oxidant (malondialdehyde, carbonyl proteins) and antioxidant (reduced glutathione, catalase activity) markers were evaluated. The results showed that Fe and Zn have the highest prooxidant effect (37 and 33% of hemolysis, respectively). Quercetin, rutin and (+)catechin exhibited strong antioxidant properties toward Fe, but this effect was decreased with respect to Zn ions. However, the Cu showed a weak antioxidant effect at the highest flavonoid concentration (200 μM), while a prooxidant effect was observed at the lowest flavonoid concentration (100 μM). These results are in agreement with the physico-chemical and antiradical data which demonstrated that binding of the metal ions (for FeNTA: (+)Catechin, KLFeNTA = 1.6(1) × 106 M-1 > Rutin, KLFeNTA = 2.0(9) × 105 M-1 > Quercetin, KLFeNTA = 1.0(7) × 105 M-1 > Q35OH, KLFeNTA = 6.3(8.7) × 104 M-1 > Quercetin3’4’OH and Quercetin 3OH, KLFeNTA ~ 2 × 104 M-1) reflects the (anti)oxidant status of the RBCs. This study reveals that flavonoids have both prooxidant and antioxidant activity depending on the nature and concentration of the flavonoids and metal ions. PMID:27788249

  6. Decontamination of Metal Ions in Soil by Supercritical CO{sub 2} Extraction with Catecholamine Ligand

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Kim, Hakwon; Park, Kwangheon [Kyunghee University, Yongin (Korea, Republic of)

    2015-10-15

    The role of fuel cladding and reactor vessels is to help prevent the leakage of radioactive materials, including the fission products. However, if these shielding materials are damaged by a severe disaster such as the Fukushima Accident, radioactive materials could leak outside of a power plant site. Indeed, after the Fukushima Accident, radioactive materials have been detected in air and water samples. The air and water pollution lead to soil pollution, which is particularly difficult to decontaminate, as soil pollution has several types that vary according to the characteristics of a pollutant or its area. The existing decontamination methods generate a secondary waste owing to use of chemical toxicity solvents. It is also disadvantageous due to the additional cost of handling them. Therefore, new effective decontamination methods that reduce the use of toxicity solvents are necessary. For example, using supercritical CO{sub 2} has been studied as a new decontamination method. This study examines the method of decontaminating metallic ions inside of the soil using supercritical CO{sub 2} and a catecholamine compound. This study examined the effects of extracting metallic ions inside the soil using supercritical CO{sub 2} and catecholamine as the ligand. Based on these results, it is evident that when only the extraction agent was used, there was no extraction effect and that only when the ligand, co-ligand, and additive were used together was there an extraction effect. Following this, the optimal extraction-agent ratio was confirmed using varying amounts of extraction agents. The most effective extraction ratio of ligand to co-ligand was 1:2 in E-9 when 0.3 ml of H{sub 2}O were added.

  7. Thermodynamic stability of binary systems involving metal ions and the 4-methoxy benzylidenepyruvate in aqueous solution

    International Nuclear Information System (INIS)

    Redigolo, H.

    1989-01-01

    A review on studies previously carried out in this laboratory involving metal ions and benzylidene-pyruvate, in aqueous solutions, is presented; emphasis is mainly placed on complexes comprising 4-Dimethyl-amino-benzylidene-pyruvate (DMBP, p K a 3.79) and 2-Chloro-4-Dimethyl-amino-benzylidene-pyruvate (2 Cl-DMBP, p k a = 3.08). In an endeavour to extend the previous work, the dissociation constant of 4-methoxy-benzylidene-pyruvic acid (H-4-Me O-BP) was determined spectrophotometrically at 25.0 +- 0.1 0 C and ionic strength 0.500 M, held with sodium perchlorate (p k a = 1.473). The complex formation equilibria in M-4-Me O-BP systems, where M = Cu(II), La(III), Pr(III), Sm(III), Lu(III), Sc (III), In(III), Ga(III) or Th(IV) were investigated, also spectrophotometrically, in the above mentioned experimental conditions. In addition, the system involving Sm(III) was reinvestigated at ionic strengths 0.100 and 2.00 M, the remaining experimental conditions being maintained. The study is mostly concerned with the determination of formation constants of 1:1 complex species (β 1 ) and spectrophotometric parameters associated with these species. The investigation of possible higher binary complexes (ML n , n > 1) was prevented by solubility limitations. For all considered metal ions, log β 1 (DMBP) > log β 1 (4-Me O-BP) indicating that the stability is governed, at least in part, by ligand basicity. (author). 121 refs, 36 figs, 20 tabs

  8. Effect of trivalent transition metal ion substitution in Dy2O3 system

    International Nuclear Information System (INIS)

    Dhilip, M.; Saravana Kumar, K.; Anbarasu, V.

    2015-01-01

    One of the very promising approaches to create novel materials is to combine different physical properties in one material to achieve rich functionality. Magnetoelectric multiferroics are attracting attention for fundamental physics due to their unique coupling behaviour between ferroelectricity, ferromagnetism and ferroelasticity and also because of their promising applications for devices in spintronics, information storage, sensing and actuation. The existence of spontaneous magnetization in the perovskite like phase (layer of perovskite) has encouraged exploring the possibility of fabrication of a multiferroic material for multifunctional devices using the concept of magnetoelectric effect. The rare earth orthoferrites (LnFeO 3 where, Ln = La, Sm, Gd, Dy, Er and Yb) are a class of materials having potential for various applications. These compounds and metal ion substituted ferrites crystallising in perovskite structure show promise as catalysts gas separators, cathodes in solid oxide fuel cells, sensor materials, magneto-optic materials and as spin valves. In this present work, Fe substituted in Dysprosium Oxide compounds were prepared by standard solid state reaction at a temperature of 1300℃. The structural analysis of the prepared samples was characterized with powder X-Ray Diffraction technique and the lattice parameters were calculated with PodwerX indexing software. The structural analysis reveals that the substitution of Fe in Dy 2 O 3 system leads to change of crystalline structure from Cubic to Tetragonal. Further, decreasing trend of volume of the unit cell confirms the occupation of smaller ionic radii element Fe in the Dy site of Dy 2 O 3 system. Hence the possibilities of incorporation of trivalent transition metal ion in to the host Dy 2 O 3 site were analyzed. (author)

  9. Studies on indigenous ion exchange resins: alkali metal ions-hydrogen ion exchange equilibria

    International Nuclear Information System (INIS)

    Shankar, S.; Kumar, Surender; Venkataramani, B.

    2001-01-01

    With a view to select a suitable ion exchange resin for the removal of radionuclides (such as cesium, strontium etc.) from low level radioactive effluents, alkali metal ion -H' exchanges on nine indigenous gel- and macroporous-type and nuclear grade resins have been studied at a total ionic strength of 0.1 mol dm .3 (in the case ofCs' -H' exchange it was 0.05 mol dm .3 ). The expected theoretical capacities were not attained by all the resins for the alkali metal ions. The water content (moles/equiv.) of the fully swollen resins for different alkali metal ionic forms do not follow the usual sequence of greater the tendency of the cation to hydrate the higher the water uptake, but a reverse trend. The ion exchange isotherms (plots of equivalent fractions of the ion in resin phase, N M1 to that in solution, N M ) were not satisfactory and sorption of cations, for most of the resins, was possible only when the acidity of the solution was lowered. The variations of the selectivity coefficient, K, with N M show that the resins are highly cross linked and the selectivity sequence: Cs + >K + >Na + >Li + , obtained for all the resins indicate that hydrated ions were involved in the exchange process. However, the increase in the selectivity was not accompanied by the release of water, but unusual uptake of water, during the exchange process. The characteristics of macroporous resins were not significantly different from those of the gel-type resins. The results are discussed in terms of heterogeneity in the polymer net work, improper sulphonation process resulting in the formation of functional groups at inaccessible sites with weak acidic character and the overall lack of control in the preparation of different resins. (author)

  10. PIGMENT CONTENT OF Chlorella vulgaris BEIJ. UNDER INFLUENCE OF THE SODIUM SELENITE AND METALS IONS

    Directory of Open Access Journals (Sweden)

    O. I.

    2016-02-01

    Full Text Available The aim of the research was to determine the conditions obtaining in the aquaculture of Chlorella vulgaris Beij. algosubstantion enriched with selenium and bioactive metals. For this purpose, the content of seaweed pigments studied by the action of sodium selenite in a concentration based on Se4+: 0.5, 5.0, 10.0 and 20.0 mg / dm3 for 1, 3 and 7 days and while exposed 10.0 mg Se4 +/dm3 and Zn2+, Mn2 +, Co2 +, Cu2 +, Fe3 + in concentrations of 5.0 mg/dm 3, 0.25, 0.002, 0.008 and 0.05 mg/dm3, respectively, within 7 days of culturing. The content of pigments was determined spectrophotometrically, the cellular walls were given off in the percoll gradient and investigated microscopically. The pigments content in Ch. vulgaris increase by 1,5–2,5 times in comparison with control sample under the influence of 10 mg Se(IV/dm3 with and without metal ions. In the same condition a ratio of chlorophylls a/b increased, that accompanied by the formation in cells of the second cell wall as the sign of successful adaptation process in the Chlorella cells under the influence of these factors. Thus, the cultivation of chlorella, enriched with selenium and bioactive metals, is possible within 7 days under the influence of 10 mg Se (IV/dm3 and mentioned concentration of these metal ions.

  11. Theory Meets Experiment: Metal Ion Effects in HCV Genomic RNA Kissing Complex Formation

    Directory of Open Access Journals (Sweden)

    Li-Zhen Sun

    2017-12-01

    Full Text Available The long-range base pairing between the 5BSL3. 2 and 3′X domains in hepatitis C virus (HCV genomic RNA is essential for viral replication. Experimental evidence points to the critical role of metal ions, especially Mg2+ ions, in the formation of the 5BSL3.2:3′X kissing complex. Furthermore, NMR studies suggested an important ion-dependent conformational switch in the kissing process. However, for a long time, mechanistic understanding of the ion effects for the process has been unclear. Recently, computational modeling based on the Vfold RNA folding model and the partial charge-based tightly bound ion (PCTBI model, in combination with the NMR data, revealed novel physical insights into the role of metal ions in the 5BSL3.2-3′X system. The use of the PCTBI model, which accounts for the ion correlation and fluctuation, gives reliable predictions for the ion-dependent electrostatic free energy landscape and ion-induced population shift of the 5BSL3.2:3′X kissing complex. Furthermore, the predicted ion binding sites offer insights about how ion-RNA interactions shift the conformational equilibrium. The integrated theory-experiment study shows that Mg2+ ions may be essential for HCV viral replication. Moreover, the observed Mg2+-dependent conformational equilibrium may be an adaptive property of the HCV genomic RNA such that the equilibrium is optimized to the intracellular Mg2+ concentration in liver cells for efficient viral replication.

  12. Structured nanoporous surfaces from hybrid block copolymer micelle films with metal ions

    International Nuclear Information System (INIS)

    Kim, Minsoo P; Yi, Gi-Ra; Kim, Hyeong Jun; Kim, Bumjoon J

    2015-01-01

    We present a novel method for producing structured nanoporous thin films using block copolymer (BCP) micelles loaded with metallic ions. The BCP micellar thin films containing gold (Au) ions were prepared by spin-coating poly(styrene-block-4-vinylpyridine) (PS-b-P4VP) micelle solutions in which Au precursors (AuCl 4 − ) were selectively loaded onto the P4VP core. When the micellar films were exposed to cetyltrimethylammonium bromide (CTAB) solutions, the Au precursors were selectively extracted from the P4VP domains due to their strong electrostatic interaction with CTAB, leading to the formation of pores in the micelles. Consequently, regularly patterned nanoporous surfaces were formed. By controlling the molecular weight (M n ) of PS-b-P4VP and the amount of Au precursors (λ) that were loaded in the P4VP domains, the pore size and depth could be tuned precisely. In particular, when a sufficient amount of Au precursors was loaded (λ  ≥ 0.3), the porous surface nanostructure was well developed. In addition, the pore size and depth of the nanostructure increased as the λ value increased. For instance, when the λ value increased from 0.3 to 1.0, the pore size increased from 22.8 nm to 28.8 nm, and the pore depth increased from 2.1 nm to 3.2 nm. Interestingly, the transition from the nonporous structures to the porous structures in the micellar film could be reversibly controlled by adding and removing the Au precursors in the film. Moreover, our method for the preparation of nanoporous films can be extended to micellar film by incorporating other metal ions such as silver (Ag) and iron (Fe). (paper)

  13. Interaction of divalent metal ions with Zn(2+)-glycerophosphocholine cholinephosphodiesterase from ox brain.

    Science.gov (United States)

    Lee, K J; Kim, M R; Kim, Y B; Myung, P K; Sok, D E

    1997-12-01

    The effect of divalent metal ions on the activity of glycerophosphocholine cholinephosphodiesterse from ox brain was examined. Zn(2+)- and Co(2+)-glycerophosphocholine cholinephosphodiesterases were prepared from the exposure of apoenzyme to Zn2+ and Co2+, respectively, and the properties of two metallo-phosphodiesterases were compared to those of native phosphodiesterase. Although two metallo-enzymes were similar in expressing Km value, optimum pH or sensitivity to Cu2+, they differed in the susceptibility to the inhibition by thiocholine or tellurite; while Co(2+)-phosphodiesterase was more sensitive to tellurites, Zn(2+)-phosphodiesterase was more susceptible to inhibition by thiocholine. In addition, Zn(2+)-phosphodiesterase was more thermo-stable than Co2+ enzyme. Separately, when properties of native phosphodiesterase were compared to those of each metallo-phosphodiesterase, native phosphodiesterase was found to be quite similar to Zn(2+)-phosphodiesterase in many respects. Even in thermo-stability, native enzyme resembled Zn(2+)-phosphodiesterase rather than Co(2+)-enzyme. Consistent with this, the stability of native phosphodiesterase was maintained in the presence of Zn2+, but not Co2+, Mn2+ was also as effective as Zn2+ in the stabilization of the enzyme. Noteworthy, the native enzyme was found to be inhibited competitively by Cu2+ with a Ki value of 20 microM, and its inhibitory action was antagonized effectively by Zn2+ or Co2+. Also, choline, another competitive inhibitor of the enzyme, appeared to antagonize the inhibitory action of Cu2+. Taken together, it is suggested that there may be multiple binding sites for divalent metal ions in the molecule of glycerophosphocholine cholinephosphodiesterase.

  14. Multiheteromacrocycles that Complex Metal Ions. Second Progress Report, 1 May 1975 -- 30 April 1976

    Science.gov (United States)

    Cram, D. J.

    1976-01-15

    Objective is to develop cyclic and polycyclic host organic compounds to complex and lipophilize metal ions. Macrorings were synthesized: (OCH{sub 2} CH{sub 2} O CH{sub 2}COCH{sub 2} COCH{sub 2}){sub 2} and (OCH{sub 2} CH{sub 2} O CH{sub 2} COCH{sub 2} COCH{sub 2}){sub 3}. The smaller ring complexes divalent metals 10{sup 1+9} times better than the open-chain model CH{sub 3} O CH{sub 2} CO CH{sub 2} COCH{sub 2} O CH{sub 3}, and the order in which metal ions are complexed is Cu{sup 2+}, UO{sub 2}{sup 2+} greater than Ni{sup 2+} greater than Fe{sup 2+}, Co{sup 2+}, Zn{sup 2+}, Cd{sup 2+} greater than Mn{sup 2+}. The UO{sub 2}{sup 2+} and Cu{sup 2+} complexes were isolated and characterized. The larger ring complexes trivalent metals 10{sup 0.9-1.7} times better than the open- chain model compound, and the order is La{sup 3+}, Ce{sup 3+} greater than Cr{sup 3+}. Five other macrocycles were also synthesized, and their binding constants with Na, K, NH{sub 4}, and Cs picrates were measured. Six compounds containing one macroring and two inward-pointing ArOH or ArOCH{sub 3} groups were also prepared and tested for binding of Li, Na, K, Rb, and NH{sub 4} picrates. Racemic compounds containing two binaphthyls and its sulfur analog were prepared. Cage-shaped multiheteromacrocycles containing ten O ligand sites or four S and six O ligand sites were prepared and the binding capability of the first compound for picrates studied. Two ring systems with phosphonate ester groups were also prepared. (DLC)

  15. DFT study of the interaction between DOTA chelator and competitive alkali metal ions.

    Science.gov (United States)

    Frimpong, E; Skelton, A A; Honarparvar, B

    2017-09-01

    1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetracetic acid (DOTA) is an important chelator for radiolabeling of pharmaceuticals. The ability of alkali metals found in the body to complex with DOTA and compete with radio metal ions can alter the radiolabeling process. Non-covalent interactions between DOTA complexed with alkali metals Li + , Na + , K + and Rb + , are investigated with density functional theory using B3LYP and ωB97XD functionals. Conformational possibilities of DOTA were explored with a varying number of carboxylic pendant arms of DOTA in close proximity to the ions. It is found that the case in which four arms of DOTA are interacting with ions is more stable than other conformations. The objective of this study is to explore the electronic structure properties upon complexation of alkali metals Li + Na + , K + and Rb + with a DOTA chelator. Interaction energies, relaxation energies, entropies, Gibbs free energies and enthalpies show that the stability of DOTA, complexed with alkali metals decreases down the group of the periodic table. Implicit water solvation affects the complexation of DOTA-ions leading to decreases in the stability of the complexes. NBO analysis through the natural population charges and the second order perturbation theory, revealed a charge transfer between DOTA and alkali metals. Conceptual DFT-based properties such as HOMO/LUMO energies, ΔE HOMO-LUMO and chemical hardness and softness indicated a decrease in the chemical stability of DOTA-alkali metal complexes down the alkali metal series. This study serves as a guide to researchers in the field of organometallic chelators, particularly, radiopharmaceuticals in finding the efficient optimal match between chelators and various metal ions. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Selective chelation-supercritical fluid extraction of metal ions from waste materials

    International Nuclear Information System (INIS)

    Wai, C.N.; Laintz, K.E.; Yonker, C.R.

    1993-01-01

    The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

  17. New developments in metal ion implantation by vacuum arc ion sources and metal plasma immersion

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1996-01-01

    Ion implantation by intense beams of metal ions can be accomplished using the dense metal plasma formed in a vacuum arc discharge embodied either in a vacuum arc ion source or in a metal plasma immersion configuration. In the former case high energy metal ion beams are formed and implantation is done in a more-or-less conventional way, and in the latter case the substrate is immersed in the plasma and repetitively pulse-biased so as to accelerate the ions at the high voltage plasma sheath formed at the substrate. A number of advances have been made in the last few years, both in plasma technology and in the surface modification procedures, that enhance the effectiveness and versatility of the methods, including for example: controlled increase of the in charge states produced; operation in a dual metal-gaseous ion species mode; very large area beam formation; macroparticle filtering; and the development of processing regimes for optimizing adhesion, morphology and structure. These complementary ion processing techniques provide the plasma tools for doing ion surface modification over a very wide parameter regime, from pure ion implantation at energies approaching the MeV level, through ion mixing at energies in the ∼1 to ∼100 keV range, to IBAD-like processing at energies from a few tens of eV to a few keV. Here the authors review the methods, describe a number of recent developments, and outline some of the surface modification applications to which the methods have been put. 54 refs., 9 figs

  18. High adsorptive γ-AlOOH(boehmite)@SiO2/Fe3O4 porous magnetic microspheres for detection of toxic metal ions in drinking water.

    Science.gov (United States)

    Wei, Yan; Yang, Ran; Zhang, Yong-Xing; Wang, Lun; Liu, Jin-Huai; Huang, Xing-Jiu

    2011-10-21

    γ-AlOOH(boehmite)@SiO(2)/Fe(3)O(4) porous magnetic microspheres with high adsorption capacity toward heavy metal ions were found to be useful for the simultaneous and selective electrochemical detection of five metal ions, such as ultratrace zinc(II), cadmium(II), lead(II), copper(II), and mercury(II), in drinking water.

  19. Process for the conversion of sugars to lactic acid and 2-hydroxy-3-butenoic acid or esters thereof comprising a metallo-silicate material and a metal ion

    DEFF Research Database (Denmark)

    2015-01-01

    A process for the preparation of lactic acid and 2-hydroxy- 3-butenoic acid or esters thereof from a sugar in the presence of a metallo-silicate material, a metal ion and a solvent, wherein the metal ion is selected from one or more of the group consisting of potassium ions, sodium ions, lithium...

  20. Selective Decontamination Effect of Metal Ions in Soil Using Supercritical CO{sub 2} and TBP Complex

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung [Kyunghee Univ., Yongin (Korea, Republic of)

    2014-10-15

    Decontamination of soil pollution is difficult because the type of contamination largely depends on the characteristics of the pollutant and the area. Also, existing soil decontamination methods generate large quantities of secondary waste and additional process costs. For this reason, new decontamination methods are always under active investigation. A method involving the use of supercritical carbon dioxide with excellent permeability in place of chemical solvents is currently being studied. Unlike other heavy metals in fission products, uranium is used as fuel, and must be handled carefully. Therefore, in this paper, we studied a supercritical carbon dioxide method for decontaminating heavy metal ions in soil using tri-n-butyl phosphate(TBP), which is well known as a ligand for the extraction of metal ions of actinium. We investigated the decontamination effect of heavy metal ions in the soil using TBP-HNO{sub 3} Complex and supercritical carbon dioxide. The study results showed that when heavy metals in soil are extracted using supercritical carbon dioxide, the extraction efficiency is different according to the type of pollutant metal ions in the soil. When TBP-HNO{sub 3} Complex is used with an extractant, uranium extraction is very effective, but lithium, strontium, and cesium extraction is not effective. Therefore, in the case of a mixture of uranium and other metals such as lithium, strontium, cesium, and so on in soil contaminated by fission product leaks from nuclear power plants, we can selectively decontaminate uranium with supercritical carbon dioxide and TBP-HNO{sub 3} Complex.