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Sample records for metal ion additives

  1. Low coefficient of thermal expansion polyimides containing metal ion additives

    Science.gov (United States)

    Stoakley, D. M.; St. Clair, A. K.

    1992-01-01

    Polyimides have become widely used as high performance polymers as a result of their excellent thermal stability and toughness. However, lowering their coefficient of thermal expansion (CTE) would increase their usefulness for aerospace and electronic applications where dimensional stability is a requirement. The incorporation of metal ion-containing additives into polyimides, resulting in significantly lowered CTE's, has been studied. Various metal ion additives have been added to both polyamic acid resins and soluble polyimide solutions in the concentration range of 4-23 weight percent. The incorporation of these metal ions has resulted in reductions in the CTE's of the control polyimides of 12 percent to over 100 percent depending on the choice of additive and its concentration.

  2. Metal-Ion Additives Reduce Thermal Expansion Of Polyimides

    Science.gov (United States)

    Stoakley, Diane M.; St. Clair, Anne K.; Emerson, Burt R., Jr.; Willis, George L.

    1994-01-01

    Polyimides widely used as high-performance polymers because of their excellent thermal stability and toughness. However, their coefficients of thermal expansion (CTE's) greater than those of metals, ceramics, and glasses. Decreasing CTE's of polyimides increase usefulness for aerospace and electronics applications in which dimensional stability required. Additives containing metal ions reduce coefficients of thermal expansion of polyimides. Reductions range from 11 to over 100 percent.

  3. 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.

  4. Influence of additives on the retention of metal ions in a soil of Bangalore, India

    Directory of Open Access Journals (Sweden)

    Dr Maya Naik

    2009-04-01

    Full Text Available Liners play an important role in minimizing migration of contaminants and are frequently constructed with natural materials serving as the primary barrier to contain chemicals and potentially harmful pollutants from municipal toxic waste leachates. To improve the performance of liners, additives like lime and cement at low percentages were added to Red Soil of Bangalore. Heavy metals like hexavalent chromium, copper and zinc and alkali metals like sodium and potassium were taken as contaminants. Batch leaching tests on 50 samples were performed according to ASTM D 3987 – 85 for soil and soil mixtures with contaminants. The heavy metals were potentiometrically monitored using ion selective mercury and platinum electrodes. The alkali metals were determined using a Flame Photometry. It has been observed that the retention of heavy metals elements followed the order copper> zinc>chromium over a period of 7 to 28 days. Chromium, zinc and copper attained equilibrium in this period as confirmed based on conductivity and pH data. Cement and lime had significant effect on copper and zinc. Specific adsorption of Cu onto CaCO3 surfaces may control Cu concentration in solution. Zn adsorption increases with pH; Zinc hydrolysed at pH > 7.7 and these hydrolyzed species are strongly adsorbed to soil surfaces. Cr was retained only by 50% and additives did not have much effect as it is subjected to nonspecific adsorption (temporary. Cr was found to be highly mobile in alkaline soils. It was observed that the retention of alkali metals follows the order: K > Na. Cement and lime had positive effect on the retention of Na and K. Sodium ion retarded immediately due to the removal of exchangeable cations, whereas potassium retarded more than sodium due to the lower hydrated radius of potassium. Scanning Electron Microscopy (SEM characterization tests were performed to understand the soil mineral structure. Regular porous, sponge like, particles were detected in

  5. Controlling Enantioselectivity in Additions to Cyclic Oxocarbenium Ions via Transition Metal Catalysis.

    Science.gov (United States)

    Watson, Mary P; Maity, Prantik

    2012-01-01

    Controlling enantioselectivity in additions to oxocarbenium ions remains a challenge in asymmetric catalysis. By catalytically generating a chiral organometallic intermediate, a copper acetylide, we have developed a novel approach for additions of carbon nucleophiles to cyclic oxocarbenium ions in high enantioselectivities and yields.

  6. Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

    Directory of Open Access Journals (Sweden)

    Matthias Leven

    2013-01-01

    Full Text Available Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components.

  7. The effect of Nb addition on mechanical properties, corrosion behavior, and metal-ion release of ZrAlCuNi bulk metallic glasses in artificial body fluid.

    Science.gov (United States)

    Qiu, C L; Liu, L; Sun, M; Zhang, S M

    2005-12-15

    Bulk metallic glasses (BMGs) of Zr(65 - x)Nb(x)- Cu(17.5)Ni(10)Al(7.5) with Nb = 0, 2, and 5 at % were prepared by copper mold casting. Compression tests reveal that the two BMGs containing Nb exhibited superior strength and plasticity to the base alloy. The corrosion behavior of the alloys obtained was investigated in artificial body fluid by electrochemical measurements. It was found that the addition of Nb significantly enhanced the corrosion resistance of the Zr-based BMG, as indicated by a remarkable increase in corrosion potential and pitting potential. XPS analysis revealed that the passive film formed after anodic polarization was enriched in aluminum oxide and depleted in phosphate ions for the BMGs containing Nb, which accounts for the improvement of corrosion resistance. On the other hand, metal-ion release of different BMGs were determined in PPb (ng/mL) level with inductively coupled plasma mass spectrometry (ICP-MS) after being immersed in artificial body fluid at 37 degrees C for 20 days. It was found that the addition of Nb considerably reduced the ion release of all kinds of metals of the base system. This is probably attributed to the promoting effect of Nb on a rapid formation of highly protective film.

  8. Metal and pharmaceutical mixtures: Is ion loss the mechanism underlying acute toxicity and widespread additive toxicity in zebrafish?

    Energy Technology Data Exchange (ETDEWEB)

    Alsop, Derek, E-mail: alsopde@mcmaster.ca; Wood, Chris M.

    2013-09-15

    Highlights: •Zebrafish larvae were used to test the acute toxicity of contaminant mixtures. •Interactions were observed between metals, ammonia and pharmaceuticals. •Larval Na{sup +} loss was observed with exposure to all acutely toxic contaminants tested. •Water quality criteria should recognize the toxic interactions between contaminants. -- Abstract: The acute toxicities and mechanisms of action of a variety of environmental contaminants were examined using zebrafish larvae (Danio rerio; 4–8 days post fertilization). Toxic interactions were observed between metals. For example, the addition of a sublethal level of nickel (15% of the LC{sub 50}, one third of the LC{sub 01}) to all copper treatments decreased the copper 96 h LC{sub 50} by 58%, while sublethal copper exposure (6% of the copper LC{sub 50}, 13% of the LC{sub 01}) decreased the cadmium 96 h LC{sub 50} by 47%. Two predictive models were assessed, the concentration addition (CA) model, which assumes similar mechanisms of action, and the independent action (IA) model, which assumes different mechanisms of action. Quantitative comparisons indicated the CA model performed better than the IA model; the latter tended to underestimate combined toxicity to a greater extent. The effects of mixtures with nickel or ammonia were typically additive, while mixtures with copper or cadmium were typically greater than additive. Larvae exposed to cadmium, copper or nickel experienced whole body ion loss. Decreases were greatest for Na{sup +} followed by K{sup +} (as high as 19% and 9%, respectively, in 24 h). Additive toxicity between copper and other pharmaceutical compounds such as fluoxetine (Prozac™), β-naphthoflavone, estrogen and 17α-ethinylestradiol were also observed. Similar to metals, acutely toxic concentrations of fluoxetine, β-naphthoflavone and ammonia all decreased whole body Na{sup +} and K{sup +}. Overall, whole body Na{sup +} loss showed the greatest correlation with mortality across a

  9. Metal Ions in Unusual Valency States.

    Science.gov (United States)

    Sellers, Robin M.

    1981-01-01

    Discusses reactivity of metal ions with the primary products of water radiolysis, hyper-reduced metal ions, zero-valent metal ions, unstable divalent ions from the reduction of bivalent ions, hyper-oxidized metal ions, and metal complexes. (CS)

  10. Investigations on the electrochemical decomposition of the electrolyte additive vinylene carbonate in Li metal half cells and lithium ion full cells

    Science.gov (United States)

    Qian, Yunxian; Schultz, Carola; Niehoff, Philip; Schwieters, Timo; Nowak, Sascha; Schappacher, Falko M.; Winter, Martin

    2016-11-01

    In this study, the decomposition of vinylene carbonate (VC) additive and its effect on the aging behavior is investigated in Li metal half cells and lithium ion full cells. Four electrolyte systems, the reference electrolyte with three VC additive amounts, i.e., 1, 5 and 10 vol% are examined with commercial LiNi1/3Mn1/3Co1/3O2 (NMC 111) cathode material and mesophase carbon microbeads (MCMB) anode material. The thickness changes of the cathode electrolyte interphase (CEI) and of the solid electrolyte interphase (SEI) after 5 constant current cycles at 0.1C and 200 constant current/constant voltage (potential) cycles at 1C are investigated for cells containing different amounts of VC. With the help of X-ray photoelectron spectroscopy (XPS) and high-performance liquid chromatography (HPLC), a correlation between CEI thickness change and electrolyte decomposition is figured out. The addition of VC leads to a thin CEI layer and a high capacity retention in a lithium metal half cell. A strong dependence of the performance on the VC concentration is found for half cells that results from the continuous consumption of electrolyte and the electrolyte additive at the Li metal counter electrode. In contrast, for full cells, even 1 vol% of VC helps to form both a stable CEI and SEI, while a larger amount of VC increases the CEI thickness, electric contact loss and the internal resistance.

  11. Metal Additive Manufacturing: A Review

    Science.gov (United States)

    Frazier, William E.

    2014-06-01

    This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

  12. [Development of metal ions analysis by ion chromatography].

    Science.gov (United States)

    Yu, Hong; Wang, Yuxin

    2007-05-01

    Analysis of metal ions by ion chromatography, including cation-exchange ion chromatography, anion-exchange ion chromatography and chelation ion chromatography, is reviewed. The cation-exchange ion chromatography is a main method for the determination of metal ions. Stationary phases in cation-exchange ion chromatography are strong acid cation exchanger (sulfonic) and weak acid cation exchanger (carboxylic). Alkali metal ions, alkaline earth metal ions, transition metal ions, rare earth metal ions, ammonium ions and amines can be analyzed by cation-exchange ion chromatography with a suitable detector. The anion-exchange ion chromatography is suitable for the separation and analysis of alkaline earth metal ions, transition metal ions and rare earth metal ions. The selectivity for analysis of metal ions with anion-exchange ion chromatography is good. Simultaneous determination of metal ions and inorganic anions can be achieved using anion-exchange ion chromatography. Chelation ion chromatography is suitable for the determination of trace metal ions in complex matrices. A total of 125 references are cited.

  13. Additive Manufacturing of Ion Thruster Optics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Plasma Controls will manufacture and test a set of ion optics for electric propulsion ion thrusters using additive manufacturing technology, also known as 3D...

  14. 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.)

  15. Systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, Robert Graham; Li, Anyin; Luo, Qingjie

    2017-08-01

    The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

  16. Systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, Robert Graham; Li, Anyin; Luo, Qingjie

    2017-01-24

    The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

  17. Bacterial antimicrobial metal ion resistance.

    Science.gov (United States)

    Hobman, Jon L; Crossman, Lisa C

    2015-05-01

    Metals such as mercury, arsenic, copper and silver have been used in various forms as antimicrobials for thousands of years with until recently, little understanding of their mode of action. The discovery of antibiotics and new organic antimicrobial compounds during the twentieth century saw a general decline in the clinical use of antimicrobial metal compounds, with the exception of the rediscovery of the use of silver for burns treatments and niche uses for other metal compounds. Antibiotics and new antimicrobials were regarded as being safer for the patient and more effective than the metal-based compounds they supplanted. Bacterial metal ion resistances were first discovered in the second half of the twentieth century. The detailed mechanisms of resistance have now been characterized in a wide range of bacteria. As the use of antimicrobial metals is limited, it is legitimate to ask: are antimicrobial metal resistances in pathogenic and commensal bacteria important now? This review details the new, rediscovered and 'never went away' uses of antimicrobial metals; examines the prevalence and linkage of antimicrobial metal resistance genes to other antimicrobial resistance genes; and examines the evidence for horizontal transfer of these genes between bacteria. Finally, we discuss the possible implications of the widespread dissemination of these resistances on re-emergent uses of antimicrobial metals and how this could impact upon the antibiotic resistance problem. © 2014 The Authors.

  18. Fully additive copper metallization on BCB

    Energy Technology Data Exchange (ETDEWEB)

    Stolle, T. [FhG-IZM Berlin (Germany); Schwencke, B.; Reichl, H.

    2000-07-01

    A fully additive copper metallization process on benzocyclobutene cyclotene trademark (BCB) has been investigated for application in MCM-D technology. The process consists of surface pretreatment of the BCB basic layer by reactive ion etching (RIE), spin-coating and photopatterning of an organic seed layer by broad-band I-line photolithography followed by developing and activation steps. The metallization of the seed patterns is performed by a 2-step process by means of electroless copper baths. A height of about 5 {mu}m selectively deposited copper can be achieved. The electrical conductivity of patterns is in the range of 80% - 85% of the bulk conductivity of pure copper. Adhesive strength tests during accelerated aging show good adhesion of copper to the BCB surface, which is influenced by RIE pretreatment, exposure dose and thermal load. Shear experiments performed with optimal treated 200 x 200 {mu}m bumps show shear forces > 150 cN. Design rules have to take into account the lateral growth of copper patterns, which is nearly equal to the vertical growth. Real spaces of {>=} 30 {mu}m between copper lines are possible. The process is considered as a low cost technology because of replacing of sputter technique, few process steps and waste reduction. (orig.)

  19. Rational Design of Metal Ion Sequestering Agents

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, Kenneth N.; Xu, Jide; Gramer, Christine

    1999-06-01

    This project addresses the fundamental issues and requirements for developing hazardous metal ion separation technologies applicable to the treatment and disposal of radioactive waste. Our research encompasses the following areas: the design and synthesis of metal ion specific sequestering ligands, structural and thermodynamic investigations of these ligand and the complexes formed with targeted metal ions, and the development and incorporation of these ligands into applied separation technologies as highly effective materials for hazardous metal ion decontamination.

  20. Additive Manufacturing of Porous Metal

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kirka, Michael M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Currently, helium is obtained through separation from natural gas. The current industrial process incurs significant costs and requires large energy resources to successfully achieve separation. Through utilizing Additive Manufacturing (AM) technologies it is possible to reduce both of these burdens when refining helium gas. The ability to engineer porosity levels within Inconel 718 discs for controlled separation of helium from natural gas was investigated. Arrays of samples fabricated using the electron beam melting process were analyzed for their relative porosity density. Based upon the measurements, full scale discs were fabricated, and subsequently tested to determine their effectiveness in separating helium from liquefied natural gas.

  1. Behavior of metal ions in bioelectrochemical systems: A review

    Science.gov (United States)

    Lu, Zhihao; Chang, Dingming; Ma, Jingxing; Huang, Guangtuan; Cai, Lankun; Zhang, Lehua

    2015-02-01

    Bioelectrochemical systems (BESs) have been focused on by many researchers to treat wastewater and recover energy or valuable chemicals from wastes. In BESs, metal ions play an important role in the conductivity of solution, reactors' internal resistance, power generation, chemical production and activity of microorganisms. Additionally, the metal ions are also involved in anodic or cathodic reaction processes directly or indirectly in BESs. This paper reviews the behavior of metal ions in BESs, including (1) increase of the conductivity of electrolyte and decrease of internal resistance, (2) transfer for desalination, (3) enhancement or inhibition of the biocatalysis in anode, (4) improvement of cathodic performance by metal ions through electron acceptance or catalysis in cathodic process and (5) behavior of metal ions on membranes. Moreover, the perspectives of BESs removing heavy metal ions in wastewater or solid waste are discussed to realize recovery, reduction and detoxification simultaneously.

  2. Large Scale Metal Additive Techniques Review

    Energy Technology Data Exchange (ETDEWEB)

    Nycz, Andrzej [ORNL; Adediran, Adeola I [ORNL; Noakes, Mark W [ORNL; Love, Lonnie J [ORNL

    2016-01-01

    In recent years additive manufacturing made long strides toward becoming a main stream production technology. Particularly strong progress has been made in large-scale polymer deposition. However, large scale metal additive has not yet reached parity with large scale polymer. This paper is a review study of the metal additive techniques in the context of building large structures. Current commercial devices are capable of printing metal parts on the order of several cubic feet compared to hundreds of cubic feet for the polymer side. In order to follow the polymer progress path several factors are considered: potential to scale, economy, environment friendliness, material properties, feedstock availability, robustness of the process, quality and accuracy, potential for defects, and post processing as well as potential applications. This paper focuses on current state of art of large scale metal additive technology with a focus on expanding the geometric limits.

  3. Laser-based additive manufacturing of metals

    CSIR Research Space (South Africa)

    Kumar, S

    2010-11-01

    Full Text Available For making metallic products through Additive Manufacturing (AM) processes, laser-based systems play very significant roles. Laser-based processes such as Selective Laser Melting (SLM) and Laser Engineered Net Shaping (LENS) are dominating processes...

  4. Metal ions, Alzheimer's disease and chelation therapy.

    Science.gov (United States)

    Budimir, Ana

    2011-03-01

    In the last few years, various studies have been providing evidence that metal ions are critically involved in the pathogenesis of major neurological diseases (Alzheimer, Parkinson). Metal ion chelators have been suggested as potential therapies for diseases involving metal ion imbalance. Neurodegeneration is an excellent target for exploiting the metal chelator approach to therapeutics. In contrast to the direct chelation approach in metal ion overload disorders, in neurodegeneration the goal seems to be a better and subtle modulation of metal ion homeostasis, aimed at restoring ionic balance. Thus, moderate chelators able to coordinate deleterious metals without disturbing metal homeostasis are needed. To date, several chelating agents have been investigated for their potential to treat neurodegeneration, and a series of 8-hydroxyquinoline analogues showed the greatest potential for the treatment of neurodegenerative diseases.

  5. Additive manufacturing technologies of porous metal implants

    Directory of Open Access Journals (Sweden)

    Yang Quanzhan

    2014-06-01

    Full Text Available Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the significant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM and electron beam melting technology (EBM are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and fine structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  6. Additive manufacturing technologies of porous metal implants

    Institute of Scientific and Technical Information of China (English)

    Zhou Linxi; Yang Quanzhan; Zhang Guirong; Zhao Fangxin; Shen Gang; Yu Bo

    2014-01-01

    Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the signiifcant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM) and electron beam melting technology (EBM) are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and ifne structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  7. Fluorescence enhancement of photoswitchable metal ion sensors

    Science.gov (United States)

    Sylvia, Georgina; Heng, Sabrina; Abell, Andrew D.

    2016-12-01

    Spiropyran-based fluorescence sensors are an ideal target for intracellular metal ion sensing, due to their biocompatibility, red emission frequency and photo-controlled reversible analyte binding for continuous signal monitoring. However, increasing the brightness of spiropyran-based sensors would extend their sensing capability for live-cell imaging. In this work we look to enhance the fluorescence of spiropyran-based sensors, by incorporating an additional fluorophore into the sensor design. We report a 5-membered monoazacrown bearing spiropyran with metal ion specificity, modified to incorporate the pyrene fluorophore. The effect of N-indole pyrene modification on the behavior of the spiropyran molecule is explored, with absorbance and fluorescence emission characterization. This first generation sensor provides an insight into fluorescence-enhancement of spiropyran molecules.

  8. Metal hydrides for lithium-ion batteries.

    Science.gov (United States)

    Oumellal, Y; Rougier, A; Nazri, G A; Tarascon, J-M; Aymard, L

    2008-11-01

    Classical electrodes for Li-ion technology operate via an insertion/de-insertion process. Recently, conversion electrodes have shown the capability of greater capacity, but have so far suffered from a marked hysteresis in voltage between charge and discharge, leading to poor energy efficiency and voltages. Here, we present the electrochemical reactivity of MgH(2) with Li that constitutes the first use of a metal-hydride electrode for Li-ion batteries. The MgH(2) electrode shows a large, reversible capacity of 1,480 mAh g(-1) at an average voltage of 0.5 V versus Li(+)/Li(o) which is suitable for the negative electrode. In addition, it shows the lowest polarization for conversion electrodes. The electrochemical reaction results in formation of a composite containing Mg embedded in a LiH matrix, which on charging converts back to MgH(2). Furthermore, the reaction is not specific to MgH(2), as other metal or intermetallic hydrides show similar reactivity towards Li. Equally promising, the reaction produces nanosized Mg and MgH(2), which show enhanced hydrogen sorption/desorption kinetics. We hope that such findings can pave the way for designing nanoscale active metal elements with applications in hydrogen storage and lithium-ion batteries.

  9. DNA as sensors and imaging agents for metal ions.

    Science.gov (United States)

    Xiang, Yu; Lu, Yi

    2014-02-17

    Increasing interest in detecting metal ions in many chemical and biomedical fields has created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal-ion-dependent DNAzymes and metal-ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attachment of these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detection. These sensors are highly sensitive (with a detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of "dipstick tests", portable fluorometers, computer-readable disks, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal-ion sensing and imaging in many fields of applications.

  10. Metal Ion Controlled Polymorphism of a Peptide

    DEFF Research Database (Denmark)

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

    2011-01-01

    , …) 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...

  11. OPERATOR BURDEN IN METAL ADDITIVE MANUFACTURING

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Amy M [ORNL; Love, Lonnie J [ORNL

    2016-01-01

    Additive manufacturing (AM) is an emerging manufacturing process that creates usable machine parts via layer-by-layer joining of a stock material. With this layer-wise approach, high-performance geometries can be created which are impossible with traditional manufacturing methods. Metal AM technology has the potential to significantly reduce the manufacturing burden of developing custom hardware; however, a major consideration in choosing a metal AM system is the required amount of operator involvement (i.e., operator burden) in the manufacturing process. The operator burden not only determines the amount of operator training and specialization required but also the usability of the system in a facility. As operators of several metal AM processes, the Manufacturing Demonstration Facility (MDF) at Oak Ridge National Labs is uniquely poised to provide insight into requirements for operator involvement in each of the three major metal AM processes. The paper covers an overview of each of the three metal AM technologies, focusing on the burden on the operator to complete the build cycle, process the part for final use, and reset the AM equipment for future builds.

  12. Recovery of metal ions by microfungal filters.

    Science.gov (United States)

    Wales, D S; Sagar, B F

    1990-01-01

    Many microfungi contain chitin/chitosan as an integral part of the cell wall structure. The binding of toxic and heavy metal ions by chitosan or partly deacetylated chitin is a direct consequence of the base strength of the primary amine group and is most effective for those metals that form complexes with ammonia. Of the microfungi studied, hyphae from Mucor mucedo and Rhizomucor miehei, after treatment with hydroxide to expose the chitin/chitosan, were found to be most effective in the capture of metal ions. Chemically treated mycelia have so far been shown to bind silver, zinc, lead, copper, nickel, cobalt, cadmium, iron and chromium, with the efficiency of metal-ion binding apparently being inversely proportional to the valency state of the metal ions to be bound. Wet-laid papers produced from mixed slurries of treated mycelia and various conventional paper-making and textile fibres have exceptionally good tensile- and bursting-strength properties, particularly in the wet state. Papers containing 1 g treated mycelia removed up to 90% of various metal ions in solution (50 cm3, 1.5 mmol dm-3) with flow rates of 0.5 cm3 cm-2 min-1. However, the total metal-ion binding capacities of single-thickness microfungal papers are limited under constant flow conditions. The total volume flowing through the system before metal-ion breakthrough occurs increases in direct proportion to the number of sheets of microfungal paper but the concomitant reduction in flow rates becomes a limiting factor. Mycelia-containing structures that allow efficient metal-ion binding at commercially acceptable flow rates are currently being investigated.

  13. Metal Ion Modeling Using Classical Mechanics.

    Science.gov (United States)

    Li, Pengfei; Merz, Kenneth M

    2017-02-08

    Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.

  14. Metal Ion Modeling Using Classical Mechanics

    Science.gov (United States)

    2017-01-01

    Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems. PMID:28045509

  15. Gas and metal ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Oaks, E. [High Current Electronics Institute, Tomsk (Russian Federation)]|[State Academy of Control System and Radioelectronics, Tomsk (Russian Federation); Yushkov, G. [High Current Electronics Institute, Tomsk (Russian Federation)

    1996-08-01

    The positive ion sources are now of interest owing to both their conventional use, e.g., as injectors in charged-particle accelerators and the promising capabilities of intense ion beams in the processes related to the action of ions on various solid surfaces. For industrial use, the sources of intense ion beams and their power supplies should meet the specific requirements as follows: They should be simple, technologically effective, reliable, and relatively low-cost. Since the scanning of an intense ion beam is a complicated problem, broad ion beams hold the greatest promise. For the best use of such beams it is desirable that the ion current density be uniformly distributed over the beam cross section. The ion beam current density should be high enough for the treatment process be accomplished for an acceptable time. Thus, the ion sources used for high-current, high-dose metallurgical implantation should provide for gaining an exposure dose of {approximately} 10{sup 17} cm{sup {minus}2} in some tens of minutes. So the average ion current density at the surface under treatment should be over 10{sup {minus}5} A/cm{sup 2}. The upper limit of the current density depends on the admissible heating of the surface under treatment. The accelerating voltage of an ion source is dictated by its specific use; it seems to lie in the range from {approximately}1 kV (for the ion source used for surface sputtering) to {approximately}100 kV and over (for the ion sources used for high-current, high-dose metallurgical implantation).

  16. 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.

  17. Capacity-controllable nanocarriers for metal ions

    NARCIS (Netherlands)

    Yan, Y.; Keizer, de A.; Cohen Stuart, M.A.; Besseling, N.A.M.

    2009-01-01

    We report on capacity-controllable nanocarrier system for metal ions based on a novel kind of polymeric microemulsion. These microemulsions are formed in mixed systems of negatively charged metal-bisligand coordination polymers (cp), positively charged homopolyelectrolyte (hp), and positive-neutral

  18. 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.

  19. Computational Design of Metal Ion Sequestering Agents

    Energy Technology Data Exchange (ETDEWEB)

    Hay, Benjamin P.; Rapko, Brian M.

    2006-06-01

    Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach for discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort.

  20. Separation of metal ions in nitrate solution by ultrasonic atomization

    Science.gov (United States)

    Sato, Masanori; Ikeno, Masayuki; Fujii, Toshitaka

    2004-11-01

    In the ultrasonic atomization of metal nitrate solutions, the molar ratio of metal ions is changed between solution and mist. Small molar metal ions tend to be transferred to mist by ultrasonic wave acceleration, while large molar ions tend to remain in solution. As a result, metal ions can be separated by ultrasonic atomization. We show experimental data and propose a conceptual mechanism for the ultrasonic separation of metal ions.

  1. Radical Addition to Iminium Ions and Cationic Heterocycles

    Directory of Open Access Journals (Sweden)

    Johannes Tauber

    2014-10-01

    Full Text Available Carbon-centered radicals represent highly useful reactive intermediates in organic synthesis. Their nucleophilic character is reflected by fast additions to electron deficient C=X double bonds as present in iminium ions or cationic heterocycles. This review covers diverse reactions of preformed or in situ-generated cationic substrates with various types of C-radicals, including alkyl, alkoxyalkyl, trifluoromethyl, aryl, acyl, carbamoyl, and alkoxycarbonyl species. Despite its high reactivity, the strong interaction of the radical’s SOMO with the LUMO of the cation frequently results in a high regioselectivity. Intra- and intermolecular processes such as the Minisci reaction, the Porta reaction, and the Knabe rearrangement will be discussed along with transition metal and photoredox catalysis or electrochemical methods to generate the odd-electron species.

  2. Metal Additive Manufacturing: A Review of Mechanical Properties (Postprint)

    Science.gov (United States)

    2016-04-21

    Metal additive manufacturing processes Direct metal laser sintering (DMLS), EOS Selective laser melting...6Al-4V AM tensile properties. Abbreviations: DMD, direct metal deposition; DMLS, direct metal laser sintering ; EBM, electron beam melting; HT, heat...100:1405–13 56. Khaing MW, Fuh JYH, Lu L. 2001. Direct metal laser sintering for rapid tooling: processing and characterisation of EOS parts. J.

  3. Chemical Shuttle Additives in Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Mary

    2013-03-31

    The goals of this program were to discover and implement a redox shuttle that is compatible with large format lithium ion cells utilizing LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} (NMC) cathode material and to understand the mechanism of redox shuttle action. Many redox shuttles, both commercially available and experimental, were tested and much fundamental information regarding the mechanism of redox shuttle action was discovered. In particular, studies surrounding the mechanism of the reduction of the oxidized redox shuttle at the carbon anode surface were particularly revealing. The initial redox shuttle candidate, namely 2-(pentafluorophenyl)-tetrafluoro-1,3,2-benzodioxaborole (BDB) supplied by Argonne National Laboratory (ANL, Lemont, Illinois), did not effectively protect cells containing NMC cathodes from overcharge. The ANL-RS2 redox shuttle molecule, namely 1,4-bis(2-methoxyethoxy)-2,5-di-tert-butyl-benzene, which is a derivative of the commercially successful redox shuttle 2,5-di-tert-butyl-1,4-dimethoxybenzene (DDB, 3M, St. Paul, Minnesota), is an effective redox shuttle for cells employing LiFePO{sub 4} (LFP) cathode material. The main advantage of ANL-RS2 over DDB is its larger solubility in electrolyte; however, ANL-RS2 is not as stable as DDB. This shuttle also may be effectively used to rebalance cells in strings that utilize LFP cathodes. The shuttle is compatible with both LTO and graphite anode materials although the cell with graphite degrades faster than the cell with LTO, possibly because of a reaction with the SEI layer. The degradation products of redox shuttle ANL-RS2 were positively identified. Commercially available redox shuttles Li{sub 2}B{sub 12}F{sub 12} (Air Products, Allentown, Pennsylvania and Showa Denko, Japan) and DDB were evaluated and were found to be stable and effective redox shuttles at low C-rates. The Li{sub 2}B{sub 12}F{sub 12} is suitable for lithium ion cells utilizing a high voltage cathode (potential that is higher

  4. 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.

  5. [Development of trace metal ion analysis].

    Science.gov (United States)

    Kobayashi, J

    2000-09-01

    Analyses of trace biologically essential or toxic ionic compounds found in the environment are very important. However, the lack of sensitivity and interference caused by coexisting components are often serious problems. To determine trace levels of metal ions without the above problems, new preconcentration and analytical methods have been developed. Firstly, three methods for the selective preconcentration of metal ions are shown below: 1) 3-Chloropyridazine-6-carbohydrazide was immobilized on glass beads supports to be used as a column packing material. Multi-metal ions were concentrated on the column and eluted selectively with several buffers and hydrochloric acid. The eluate was analyzed off-line by flame atomized-atomic absorption spectrometry (AAS). This method was able to determine sub-ppb levels of cupper- and cadmium-ions in environmental samples. 2) Salicylideneamino-2-thiophenol was immobilized on the supports. Aluminum ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed off-line by flameless-AAS or on-line by flow injection analysis using pyrocatechol violet for a post-column colorimetric reagent. These methods were able to determine ppb-ppt levels of aluminium in environmental samples and were suitable for its state-analysis. 3) Bathocuproinesulfonic acid was immobilized on the supports. Copper ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed on-line by flow injection analysis using bathocuproinesulfonic acid. This method was able to determine sub-ppb levels of copper in environmental samples. On the other hand, to analyze simultaneously trace metal ions and anions, capillary electrophoresis was performed using ethylenediaminetetraacetic acid as an electrolyte component. Simultaneous determination of several ions in mineral waters was achieved by the system.

  6. Chitosan Hydrogel Structure Modulated by Metal Ions

    Science.gov (United States)

    Nie, Jingyi; Wang, Zhengke; Hu, Qiaoling

    2016-10-01

    As one of the most important polysaccharide, chitosan (CS) has generated a great deal of interest for its desirable properties and wide applications. In the utilization of CS materials, hydrogel is a major and vital branch. CS has the ability to coordinate with many metal ions by a chelation mechanism. While most researchers focused on the applications of complexes between CS and metal ions, the complexes can also influence gelation process and structure of CS hydrogel. In the present work, such influence was studied with different metal ions, revealing two different kinds of mechanisms. Strong affinity between CS and metal ions leads to structural transition from orientation to multi-layers, while weak affinity leads to composite gel with in-situ formed inorganic particles. The study gave a better understanding of the gelation mechanism and provided strategies for the modulation of hydrogel morphology, which benefited the design of new CS-based materials with hierarchical structure and facilitated the utilization of polysaccharide resources.

  7. A metal ion regulated artificial metalloenzyme

    NARCIS (Netherlands)

    Bersellini, Manuela; Roelfes, Gerard

    2017-01-01

    Regulation of enzyme activity is essential in living cells. The rapidly increasing number of designer enzymes with new-to-nature activities makes it necessary to develop novel strategies for controlling their catalytic activity. Here we present the development of a metal ion regulated artificial met

  8. Metal-air cell with performance enhancing additive

    Energy Technology Data Exchange (ETDEWEB)

    Friesen, Cody A; Buttry, Daniel

    2015-11-10

    Systems and methods drawn to an electrochemical cell comprising a low temperature ionic liquid comprising positive ions and negative ions and a performance enhancing additive added to the low temperature ionic liquid. The additive dissolves in the ionic liquid to form cations, which are coordinated with one or more negative ions forming ion complexes. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. The ion complexes improve oxygen reduction thermodynamics and/or kinetics relative to the ionic liquid without the additive.

  9. Additive Manufacturing: Reproducibility of Metallic Parts

    Directory of Open Access Journals (Sweden)

    Konda Gokuldoss Prashanth

    2017-02-01

    Full Text Available The present study deals with the properties of five different metals/alloys (Al-12Si, Cu-10Sn and 316L—face centered cubic structure, CoCrMo and commercially pure Ti (CP-Ti—hexagonal closed packed structure fabricated by selective laser melting. The room temperature tensile properties of Al-12Si samples show good consistency in results within the experimental errors. Similar reproducible results were observed for sliding wear and corrosion experiments. The other metal/alloy systems also show repeatable tensile properties, with the tensile curves overlapping until the yield point. The curves may then follow the same path or show a marginal deviation (~10 MPa until they reach the ultimate tensile strength and a negligible difference in ductility levels (of ~0.3% is observed between the samples. The results show that selective laser melting is a reliable fabrication method to produce metallic materials with consistent and reproducible properties.

  10. Material Removes Heavy Metal Ions From Water

    Science.gov (United States)

    Philipp, Warren H., Jr.; Street, Kenneth W.; Hill, Carol; Savino, Joseph M.

    1995-01-01

    New high capacity ion-exchange polymer material removes toxic metal cations from contaminated water. Offers several advantages. High sensitivities for such heavy metals as lead, cadmium, and copper and capable of reducing concentrations in aqueous solutions to parts-per-billion range. Removes cations even when calcium present. Material made into variety of forms, such as thin films, coatings, pellets, and fibers. As result, adapted to many applications to purify contaminated water, usually hard wherever found, whether in wastewater-treatment systems, lakes, ponds, industrial plants, or homes. Another important feature that adsorbed metals easily reclaimed by either destructive or nondestructive process. Other tests show ion-exchange polymer made inexpensively; easy to use; strong, flexible, not easily torn; and chemically stable in storage, in aqueous solutions, and in acidic or basic solution.

  11. EFFECTS OF METAL IONS ON THE CONFORMATIONAL CHANGES OF DNA

    Institute of Scientific and Technical Information of China (English)

    G. Q. Liu; Y.Y. Meng; S.H. Liu; Y.H. Hu

    2005-01-01

    DNA takes on multi-different conformations such as A-, B-, C-, D- and Z-form. These conformations can transit to one another when DNA deposited in some metal ions solutions or when changing the concentrations of the same metal ions. Here, several major conformational transitions of DNA induced by metal ions under different environment were introduced and the mechanism of the interaction of metal ions with DNA was discuss in detail.

  12. 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.

  13. Additive Manufacturing of Metal Structures at the Micrometer Scale.

    Science.gov (United States)

    Hirt, Luca; Reiser, Alain; Spolenak, Ralph; Zambelli, Tomaso

    2017-01-04

    Currently, the focus of additive manufacturing (AM) is shifting from simple prototyping to actual production. One driving factor of this process is the ability of AM to build geometries that are not accessible by subtractive fabrication techniques. While these techniques often call for a geometry that is easiest to manufacture, AM enables the geometry required for best performance to be built by freeing the design process from restrictions imposed by traditional machining. At the micrometer scale, the design limitations of standard fabrication techniques are even more severe. Microscale AM thus holds great potential, as confirmed by the rapid success of commercial micro-stereolithography tools as an enabling technology for a broad range of scientific applications. For metals, however, there is still no established AM solution at small scales. To tackle the limited resolution of standard metal AM methods (a few tens of micrometers at best), various new techniques aimed at the micrometer scale and below are presently under development. Here, we review these recent efforts. Specifically, we feature the techniques of direct ink writing, electrohydrodynamic printing, laser-assisted electrophoretic deposition, laser-induced forward transfer, local electroplating methods, laser-induced photoreduction and focused electron or ion beam induced deposition. Although these methods have proven to facilitate the AM of metals with feature sizes in the range of 0.1-10 µm, they are still in a prototype stage and their potential is not fully explored yet. For instance, comprehensive studies of material availability and material properties are often lacking, yet compulsory for actual applications. We address these items while critically discussing and comparing the potential of current microscale metal AM techniques.

  14. Ion irradiation effects on metallic nanocrystals

    Science.gov (United States)

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C. S.; Foran, G. J.; Cookson, D. J.; Byrne, A. P.; Ridgway, M. C.

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO2. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO2 interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  15. Ohmic model for electrodeposition of metallic ions

    Energy Technology Data Exchange (ETDEWEB)

    Gliozzi, A.S. [Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 29, 10129 Torino (Italy); Alexe-Ionescu, A.L. [Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 29, 10129 Torino (Italy); Department of Physics, University Politehnica of Bucharest, Splaiul Independentei 313, 060042 Bucharest (Romania); Barbero, G., E-mail: giovanni.barbero@polito.it [Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 29, 10129 Torino (Italy)

    2015-10-23

    An ohmic model to describe the electrodeposition of metallic ions on the electrodes is proposed. We assume that the ionic distribution is homogeneous across the electrolytic cell, and that the ionic current is due to the bulk electric field. The nucleation in the electrodeposition is supposed to be well described by a kinetic equation at the electrode, taking into account the neutralization of metallic ions on the electrodes. Two cases are considered. In the first case the characteristic time describing the neutralization of the ions is supposed to be negligible with respect to the flight time of the ions across the cell. In this framework the bulk electric field coincides with the external electric field, and our analysis gives analytical formulae for the surface density of deposited ions and for the electric current in the external circuit. The case where the two characteristic times are comparable, and the effective electric field in the bulk depends on the surface deposition, is considered too. In this case the ordinary differential equations describing the ionic distribution and the adsorption phenomenon have to be solved numerically. The agreement between the presented model and the experimental results published by several groups is reasonably good.

  16. Effects of metal ion adduction on the gas-phase conformations of protein ions.

    Science.gov (United States)

    Flick, Tawnya G; Merenbloom, Samuel I; Williams, Evan R

    2013-11-01

    Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of α-lactalbumin, which specifically binds one Ca(2+), is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution.

  17. Liquid metal ion source analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, P.

    1986-06-14

    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 preliminary on-axis energy distribution measurements of a gallium source operating between 0.26 and 30.0 ..mu..A have been made. These results closely agree with measurements reported by other workers, confirming the unusual FWHM behaviour of gallium sources below approx. 2 ..mu..A.

  18. Liquid metal ion source assembly for external ion injection into an electron string ion source (ESIS)

    Energy Technology Data Exchange (ETDEWEB)

    Segal, M. J., E-mail: mattiti@gmail.com [iThemba LABS, P.O. Box 722, Somerset West 7130 (South Africa); University of Cape Town, Rondebosch, Cape Town 7700 (South Africa); Bark, R. A.; Thomae, R. [iThemba LABS, P.O. Box 722, Somerset West 7130 (South Africa); Donets, E. E.; Donets, E. D.; Boytsov, A.; Ponkin, D.; Ramsdorf, A. [Joint Institute for Nuclear Research, Joloit-Curie 6, 141980 Dubna, Moscow Region (Russian Federation)

    2016-02-15

    An assembly for a commercial Ga{sup +} liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)—JINR (Dubna, Russia) collaboration. First, results on Ga{sup +} ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga{sup +} and Au{sup +} ion beams will be reported as well.

  19. Solution NMR refinement of a metal ion bound protein using metal ion inclusive restrained molecular dynamics methods

    Energy Technology Data Exchange (ETDEWEB)

    Chakravorty, Dhruva K.; Wang Bing [University of Florida, Department of Chemistry and the Quantum Theory Project (United States); Lee, Chul Won [Chonnam National University, Department of Chemistry (Korea, Republic of); Guerra, Alfredo J.; Giedroc, David P., E-mail: giedroc@indiana.edu [Indiana University, Department of Chemistry (United States); Merz, Kenneth M., E-mail: kmerz1@gmail.com [University of Florida, Department of Chemistry and the Quantum Theory Project (United States)

    2013-06-15

    Correctly calculating the structure of metal coordination sites in a protein during the process of nuclear magnetic resonance (NMR) structure determination and refinement continues to be a challenging task. In this study, we present an accurate and convenient means by which to include metal ions in the NMR structure determination process using molecular dynamics (MD) simulations constrained by NMR-derived data to obtain a realistic and physically viable description of the metal binding site(s). This method provides the framework to accurately portray the metal ions and its binding residues in a pseudo-bond or dummy-cation like approach, and is validated by quantum mechanical/molecular mechanical (QM/MM) MD calculations constrained by NMR-derived data. To illustrate this approach, we refine the zinc coordination complex structure of the zinc sensing transcriptional repressor protein Staphylococcus aureus CzrA, generating over 130 ns of MD and QM/MM MD NMR-data compliant sampling. In addition to refining the first coordination shell structure of the Zn(II) ion, this protocol benefits from being performed in a periodically replicated solvation environment including long-range electrostatics. We determine that unrestrained (not based on NMR data) MD simulations correlated to the NMR data in a time-averaged ensemble. The accurate solution structure ensemble of the metal-bound protein accurately describes the role of conformational sampling in allosteric regulation of DNA binding by zinc and serves to validate our previous unrestrained MD simulations of CzrA. This methodology has potentially broad applicability in the structure determination of metal ion bound proteins, protein folding and metal template protein-design studies.

  20. Liquid metal alloy ion sources—An alternative for focussed ion beam technology

    Science.gov (United States)

    Bischoff, Lothar; Mazarov, Paul; Bruchhaus, Lars; Gierak, Jacques

    2016-06-01

    Today, Focused Ion Beam (FIB) processing is nearly exclusively based on gallium Liquid Metal Ion Sources (LMIS). But, many applications in the μm- or nm range could benefit from ion species other than gallium: local ion implantation, ion beam mixing, ion beam synthesis, or Focused Ion Beam Lithography (IBL). Therefore, Liquid Metal Alloy Ion Sources (LMAIS) represent a promising alternative to expand the remarkable application fields for FIB. Especially, the IBL process shows potential advantages over, e.g., electron beam or other lithography techniques: direct, resistless, and three-dimensional patterning, enabling a simultaneous in-situ process control by cross-sectioning and inspection. Taking additionally into account that the used ion species influences significantly the physical and chemical nature of the resulting nanostructures—in particular, the electrical, optical, magnetic, and mechanic properties leading to a large potential application area which can be tuned by choosing a well suited LMAIS. Nearly half of the elements of the periodic table are recently available in the FIB technology as a result of continuous research in this area during the last forty years. Key features of a LMAIS are long life-time, high brightness, and stable ion current. Recent developments could make these sources feasible for nano patterning issues as an alternative technology more in research than in industry. The authors will review existing LMAIS, LMIS other than Ga, and binary and ternary alloys. These physical properties as well as the fabrication technology and prospective domains for modern FIB applications will similarly be reviewed. Other emerging ion sources will be also presented and their performances discussed.

  1. Rational Design of Metal Ion Sequestering Agents

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, Kenneth N.

    2000-09-30

    The discriminate bonding of metal ions is a challenge to the synthetic chemist and a phenomenon of considerable practical importance.1 An important feature of many technical applications is the specific or preferential binding of a single metal ion in the presence of many metals. Examples range from large-volume uses (e.g. ferric EDTA as a plant food, calcium complexing agents as water softeners or anticaking formulations) to very high technology applications (technetium complexation in radiopharmaceuticals, synthetic metalloenzymes). We are interested in efficient and discriminate binding of actinides for waste stream remediation. Actinides represent a major and long-lived contaminant in nuclear waste. While the separation of actinides from other radioactive components of waste, such as Sr and Cs, is relatively well established, the separation of actinides from each other and in complex solutions (e.g. those found in tank wastes) is not as well resolved. The challenge of designing metal-specific (actinide) ligands is facilitated by examples from nature. Bacteria synthesize Fe(III)-specific ligands, called siderophores, to sequester Fe(III) from the environment and return it to the cell. The similarities between Fe(III) and Pu(IV) (their charge-to-size ratios and acidity), make the siderophores prototypical for designing actinide-specific ligands. The chelating groups present in siderophores are usually hydroxamic acids and catecholamides. We have developed derivatives of these natural products which have improved properties. The catechol derivatives are the 2,3-dihydroxyterephthalamides (TAMs), and 3,4-dihydroxysulfonamides (SFAMs), and the hydroxamic acid derivatives are three isomers of hydroxypyridinones, 1,2- HOPO, 3,2-HOPO, and 3,4-HOPO. All of these ligands are attached to molecular backbones by amides and a very important feature of HOPO and CAM ligands is a strong hydrogen bonds formed between the amide proton and the adjacent phenolic oxygen in the metal

  2. Laser materials based on transition metal ions

    Science.gov (United States)

    Moncorgé, Richard

    2017-01-01

    The purpose of this presentation is to review the spectroscopic properties of the main laser materials based on transition metal ions which lead to noticeable laser performance at room temperature and, for very few cases, because of unique properties, when they are operated at cryogenic temperatures. The description also includes the materials which are currently being used as saturable absorbers for passive-Q-switching of a variety of other near- and mid-infrared solid state lasers. A substantial part of the article is devoted first to the description of the energy levels and of the absorption and emission transitions of the transition metal ions in various types of environments by using the well-known Tanabe-Sugano diagrams. It is shown in particular how these diagrams can be used along with other theoretical considerations to understand and describe the spectroscopic properties of ions sitting in crystal field environments of near-octahedral or near-tetrahedral symmetry. The second part is then dedicated to the description (positions and intensities) of the main absorption and emission features which characterize the different types of materials.

  3. Silane as Electrolyte Additives for Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    Q.Xia; Y.P.Wu

    2007-01-01

    1 Results In order to overcome the inherent incompatibility of PC with graphite in the lithium ion battery system, improve their electrochemical performance at low temperature,phenyl tris-2-methoxydiethoxy silane (PTMS) has been studied as an additive to the PC-based electrolyte of lithium ion batteries with graphite anode. From the cyclic voltammogram for the graphite anode in the PC-based electrolyte,we find that in the case of the electrolyte without the additive,there is a large irreversible peak ne...

  4. 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.

  5. Metal ions potentiate microglia responsiveness to endotoxin.

    Science.gov (United States)

    Rachmawati, Dessy; Peferoen, Laura A N; Vogel, Daphne Y S; Alsalem, Inás W A; Amor, Sandra; Bontkes, Hetty J; von Blomberg, B Mary E; Scheper, Rik J; van Hoogstraten, Ingrid M W

    2016-02-15

    Oral metal exposure has been associated with diverse adverse reactions, including neurotoxicity. We showed previously that dentally applied metals activate dendritic cells (MoDC) via TLR4 (Ni, Co, Pd) and TLR3 (Au). It is still unknown whether the low levels of dental metals reaching the brain can trigger local innate cells or prime them to become more responsive. Here we tested whether dentally applied metals (Cr, Fe, Co, Ni, Cu, Zn, Au, Hg) activate primary human microglia in vitro and, as a model, monocytic THP-1-cells, in high non-toxic as well as near-physiological concentrations. In addition the effects of 'near-physiological' metal exposure on endotoxin (LPS) responsiveness of these cells were evaluated. IL-8 and IL-6 production after 24h was used as read out. In high, non-toxic concentrations all transition metals except Cr induced IL-8 and IL-6 production in microglia, with Ni and Co providing the strongest stimulation. When using near-physiological doses (up to 10× the normal plasma concentration), only Zn and Cu induced significant IL-8 production. Of note, the latter metals also markedly potentiated LPS responsiveness of microglia and THP-1 cells. In conclusion, transition metals activate microglia similar to MoDCs. In near-physiological concentrations Zn and Cu are the most effective mediators of innate immune activation. A clear synergism between innate responses to Zn/Cu and LPS was observed, shedding new light on the possible relation between oral metal exposure and neurotoxicity.

  6. Metal is not inert: role of metal ions released by biocorrosion in aseptic loosening--current concepts.

    Science.gov (United States)

    Cadosch, Dieter; Chan, Erwin; Gautschi, Oliver P; Filgueira, Luis

    2009-12-15

    Metal implants are essential therapeutic tools for the treatment of bone fractures and joint replacements. The metals and metal alloys used in contemporary orthopedic and trauma surgery are well tolerated by the majority of patients. However, complications resulting from inflammatory and immune reactions to metal implants have been well documented. This review briefly discusses the different mechanisms of metal implant corrosion in the human body, which lead to the release of significant levels of metal ions into the peri-implant tissues and the systemic blood circulation. Additionally, this article reviews the effects of the released ions on bone metabolism and the immune system and discusses their involvement in the pathophysiological mechanisms of aseptic loosening and metal hypersensitivity in patients with metal implants.

  7. Metal-ion rescue revisited: biochemical detection of site-bound metal ions important for RNA folding.

    Science.gov (United States)

    Frederiksen, John K; Li, Nan-Sheng; Das, Rhiju; Herschlag, Daniel; Piccirilli, Joseph A

    2012-06-01

    Within the three-dimensional architectures of RNA molecules, divalent metal ions populate specific locations, shedding their water molecules to form chelates. These interactions help the RNA adopt and maintain specific conformations and frequently make essential contributions to function. Defining the locations of these site-bound metal ions remains challenging despite the growing database of RNA structures. Metal-ion rescue experiments have provided a powerful approach to identify and distinguish catalytic metal ions within RNA active sites, but the ability of such experiments to identify metal ions that contribute to tertiary structure acquisition and structural stability is less developed and has been challenged. Herein, we use the well-defined P4-P6 RNA domain of the Tetrahymena group I intron to reevaluate prior evidence against the discriminatory power of metal-ion rescue experiments and to advance thermodynamic descriptions necessary for interpreting these experiments. The approach successfully identifies ligands within the RNA that occupy the inner coordination sphere of divalent metal ions and distinguishes them from ligands that occupy the outer coordination sphere. Our results underscore the importance of obtaining complete folding isotherms and establishing and evaluating thermodynamic models in order to draw conclusions from metal-ion rescue experiments. These results establish metal-ion rescue as a rigorous tool for identifying and dissecting energetically important metal-ion interactions in RNAs that are noncatalytic but critical for RNA tertiary structure.

  8. Interaction of lactic acid bacteria with metal ions: opportunities for improving food safety and quality.

    Science.gov (United States)

    Mrvčić, Jasna; Stanzer, Damir; Solić, Ema; Stehlik-Tomas, Vesna

    2012-09-01

    Certain species of lactic acid bacteria (LAB), as well as other microorganisms, can bind metal ions to their cells surface or transport and store them inside the cell. Due to this fact, over the past few years interactions of metal ions with LAB have been intensively investigated in order to develop the usage of these bacteria in new biotechnology processes in addition to their health and probiotic aspects. Preliminary studies in model aqueous solutions yielded LAB with high absorption potential for toxic and essential metal ions, which can be used for improving food safety and quality. This paper provides an overview of results obtained by LAB application in toxic metal ions removing from drinking water, food and human body, as well as production of functional foods and nutraceutics. The biosorption abilities of LAB towards metal ions are emphasized. The binding mechanisms, as well as the parameters influencing the passive and active uptake are analyzed.

  9. Experiments and Researches on Production of Highly Charged Metallic Ions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To satisfy the requirements of HIRFL (Heavy Ion Research Facility in Lanzhou), series of experiments have been done to produce metallic ion beams on the 14.5 GHz ECR ion source. By now, numerous methods have been tested, in which oven heating and MIVOC (Metallic Ion from Volatile Compounds) are both included.According to the experiments, the results show that oven heating is much better than MIVOC. In most of our

  10. Effects of metal ions on recombinant calcineurin A subunit

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Effects of metal ions on activities and solution conformations of calcineurin A subunit have been examined.The ability of several metal ions to activate calcineurin A has been tested with Ni2+>Mn2+>Mg2+/Ca2+.The corresponding CD spectra and intrinsic fluorescent emission spectra show that calcineurin A exists in different metal ion-dependent conformation states.Effects of the different concentritions of Ni2+ on activities and solution conformations of calcineurin A have been tested too.Results indicate that effects of these metal ions to activate calcineurin are due to their conformational changes.

  11. Plasma immersion ion implantation for reducing metal ion release

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, C.; Garcia, J. A.; Maendl, S.; Pereiro, R.; Fernandez, B.; Rodriguez, R. J. [Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain); Leibniz-Institut fuer Oberflaechenmodifizierung, 04318 Leipzig (Germany); Universidad de Oviedo, Departamento Quimica Fisica y Analitica (Spain); Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain)

    2012-11-06

    Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

  12. A novel high-efficiency methodology for metal additive manufacturing

    Science.gov (United States)

    Du, Jun; Wei, Zhengying; Wang, Xin; Fang, Xuewei; Zhao, Guangxi

    2016-11-01

    Metal additive manufacturing (AM) offers unrivalled design freedom with the ability to manufacture complex parts. However, the high capital costs and slow throughput printing have severely restricted its application. In this paper, a new metal AM process, referred to as the "metal fused-coating additive manufacturing (MFCAM)", was developed for highly efficient metal parts production. This new process is the combination of metal fused-coating process and laser surface melting process. A two-dimensional numerical model was established to provide an insight into the primary thermo-physical phenomena occurring in the MFCAM process. Experiments of single-track formation were conducted using MFCAM to validate the feasibility of the proposed process. The good agreement between experimental and simulated results demonstrated the reasonableness of the established models.

  13. Studies on the Interaction between Catechin and Metal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Jieun; Yang, Ikjun; Park, Okhyun; Park, Hyoungryun [Chonnam National Univ., Gwangju (Korea, Republic of); Bark, Kimin [Gyeongsang National Univ., Chinju (Korea, Republic of); Park, Chulho [Nambu Univ., Gwangju (Korea, Republic of)

    2012-12-15

    In conclusion, the UV-vis absorption spectra of the deaerated methanolic solution reacted with metal ions such as Cu{sup 2+}, Zn{sup 2+}, Co{sup 2+}, and Fe{sup 3+} were changed as time passed after adding catechin followed by addition of catechin to methanol. This is strongly dependent not only on the presence of metal ion but on the storage time of the solution. The change has relevance to the oxidation of catechin. Oxidation of catechin is first initiated by the dissociation of -OH part of the catechol moiety in methanol and then the ionized anion forms are converted into their oxidized forms called quinones. The higher the standard reduction potential for metal-ion, the faster the oxidation occurs. The steady-state fluorescence emission spectra of catechin changed depending on the storage time of the solution. This finding indicates that oxidation of catechin is undergone by a sequence of multistep reactions in deaerated methanol solution.

  14. Conformational thermodynamics of metal-ion binding to a protein

    Science.gov (United States)

    Das, Amit; Chakrabarti, J.; Ghosh, Mahua

    2013-08-01

    Conformational changes in proteins induced by metal-ions play extremely important role in various cellular processes and technological applications. Dihedral angles are suitable conformational variables to describe microscopic conformations of a biomacromolecule. Here, we use the histograms of the dihedral angles to study the thermodynamics of conformational changes of a protein upon metal-ion binding. Our method applied to Ca2+ ion binding to an important metalloprotein, Calmodulin, reveals different thermodynamic changes in different metal-binding sites. The ligands coordinating to Ca2+ ions also play different roles in stabilizing the metal-ion coordinated protein-structure. Metal-ion binding induce remarkable thermodynamic changes in distant part of the protein via modification of secondary structural elements.

  15. Epitaxy and Microstructure Evolution in Metal Additive Manufacturing

    Science.gov (United States)

    Basak, Amrita; Das, Suman

    2016-07-01

    Metal additive manufacturing (AM) works on the principle of incremental layer-by-layer material consolidation, facilitating the fabrication of objects of arbitrary complexity through the controlled melting and resolidification of feedstock materials by using high-power energy sources. The focus of metal AM is to produce complex-shaped components made of metals and alloys to meet demands from various industrial sectors such as defense, aerospace, automotive, and biomedicine. Metal AM involves a complex interplay between multiple modes of energy and mass transfer, fluid flow, phase change, and microstructural evolution. Understanding the fundamental physics of these phenomena is a key requirement for metal AM process development and optimization. The effects of material characteristics and processing conditions on the resulting epitaxy and microstructure are of critical interest in metal AM. This article reviews various metal AM processes in the context of fabricating metal and alloy parts through epitaxial solidification, with material systems ranging from pure-metal and prealloyed to multicomponent materials. The aim is to cover the relationships between various AM processes and the resulting microstructures in these material systems.

  16. The kinetics of bivalent metal ion dissociation from myosin subfragments.

    Science.gov (United States)

    Bennett, A J; Bagshaw, C R

    1986-01-01

    Bivalent metal ions have multiple roles in subunit association and ATPase regulation in scallop adductor-muscle myosin. To help elucidate these functions, the rates of Ca2+ and Mg2+ dissociation from the non-specific high-affinity sites on the regulatory light chains were measured and compared with those of rabbit skeletal-muscle myosin subfragments. Ca2+ dissociation had a rate constant of about 0.7 s-1 in both species, as measured by the time course of the pH change on EDTA addition. Mg2+ dissociation had a rate constant of 0.05 s-1, as monitored by its displacement with the paramagnetic Mn2+ ion. It is concluded that the exchange between Ca2+ and Mg2+ at the non-specific site, on excitation of both skeletal and adductor muscles, is too slow to contribute to the activation itself. The release of bivalent metal ions from the non-specific site is, however, the first step in release of the scallop regulatory light chain (Bennett & Bagshaw (1986) Biochem. J. 233, 179-186). In scallop myosin additional specific sites are present, which can bind Ca2+ rapidly, to effect activation of the ATPase. In the course of this work, Ca2+ dissociation from EGTA was studied as a model system. This gave rates of 1 s-1 and 0.3 s-1 at pH 7.0 and pH 8.0 respectively.

  17. Applications of Metal Additive Manufacturing in Veterinary Orthopedic Surgery

    Science.gov (United States)

    Harrysson, Ola L. A.; Marcellin-Little, Denis J.; Horn, Timothy J.

    2015-03-01

    Veterinary medicine has undergone a rapid increase in specialization over the last three decades. Veterinarians now routinely perform joint replacement, neurosurgery, limb-sparing surgery, interventional radiology, radiation therapy, and other complex medical procedures. Many procedures involve advanced imaging and surgical planning. Evidence-based medicine has also become part of the modus operandi of veterinary clinicians. Modeling and additive manufacturing can provide individualized or customized therapeutic solutions to support the management of companion animals with complex medical problems. The use of metal additive manufacturing is increasing in veterinary orthopedic surgery. This review describes and discusses current and potential applications of metal additive manufacturing in veterinary orthopedic surgery.

  18. Porosity Measurements and Analysis for Metal Additive Manufacturing Process Control

    OpenAIRE

    Slotwinski, John A; Garboczi, Edward J.; Hebenstreit, Keith M

    2014-01-01

    Additive manufacturing techniques can produce complex, high-value metal parts, with potential applications as critical metal components such as those found in aerospace engines and as customized biomedical implants. Material porosity in these parts is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants - since surface-breaking pores allows for better integration with biological tissue. Changes in a part’s porosity durin...

  19. In vitro cytotoxicity of metallic ions released from dental alloys

    NARCIS (Netherlands)

    Milheiro, A.; Nozaki, K.; Kleverlaan, C.J.; Muris, J.; Miura, H.; Feilzer, A.J.

    2016-01-01

    The cytotoxicity of a dental alloy depends on, but is not limited to, the extent of its corrosion behavior. Individual ions may have effects on cell viability that are different from metals interacting within the alloy structure. We aimed to investigate the cytotoxicity of individual metal ions in c

  20. Metal ion binding to peptides: Oxygen or nitrogen sites?

    NARCIS (Netherlands)

    Dunbar, R. C.; Polfer, N. C.; G. Berden,; Oomens, J.

    2012-01-01

    Infrared multiple-photon dissociation (IRMPD) spectroscopy was used to probe the conformations of gas-phase metal-ion complexes between a series of five metal ions and six small peptide ligands. This report is presented in recognition and tribute for the Armentrout group's long and hugely produ

  1. Metal ion binding to peptides: oxygen or nitrogen sites?

    NARCIS (Netherlands)

    R.C. Dunbar; N.C. Polfer; G. Berden; J. Oomens

    2012-01-01

    Infrared multiple-photon dissociation (IRMPD) spectroscopy was used to probe the conformations of gas-phase metal-ion complexes between a series of five metal ions and six small peptide ligands. This report is presented in recognition and tribute for the Armentrout group's long and hugely productive

  2. In vitro cytotoxicity of metallic ions released from dental alloys

    NARCIS (Netherlands)

    Milheiro, A.; Nozaki, K.; Kleverlaan, C.J.; Muris, J.; Miura, H.; Feilzer, A.J.

    2016-01-01

    The cytotoxicity of a dental alloy depends on, but is not limited to, the extent of its corrosion behavior. Individual ions may have effects on cell viability that are different from metals interacting within the alloy structure. We aimed to investigate the cytotoxicity of individual metal ions in

  3. Cognate and noncognate metal ion coordination in metal-specific metallothioneins: the Helix pomatia system as a model.

    Science.gov (United States)

    Palacios, Oscar; Pérez-Rafael, Sílvia; Pagani, Ayelen; Dallinger, Reinhard; Atrian, Sílvia; Capdevila, Mercè

    2014-08-01

    The Helix pomatia metallothionein (MT) system, namely, its two highly specific forms, HpCdMT and HpCuMT, has offered once again an optimum model to study metal-protein specificity. The present work investigates the most unexplored aspect of the coordination behavior of MT polypeptides with respect to either cognate or noncognate metal ions, as opposed to the standard studies of cognate metal ion coordination. To this end, we analyzed the in vivo synthesis of the corresponding complexes with their noncognate metals, and we performed a detailed spectroscopic and spectrometric study of the Zn(2+)/Cd(2+) and Zn(2+)/Cu(+) in vitro replacement reactions on the initial Zn-HpMT species. An HpCuMTAla site-directed mutant, exhibiting differential Cu(+)-binding abilities in vivo, was also included in this study. We demonstrate that when an MT binds its cognate metal, it yields well-folded complexes of limited stoichiometry, representative of minimal-energy conformations. In contrast, the incorporation of noncognate metal ions is better attributed to an unspecific reaction of cysteinic thiolate groups with metal ions, which is dependent on their concentration in the surrounding milieu, where no minimal-energy structure is reached, and otherwise, the MT peptide acts as a multidentate ligand that will bind metal ions until its capacity has been saturated. Additionally, we suggest that previous binding of an MT polypeptide with its noncognate metal ion (e.g., binding of Zn(2+) to the HpCuMT isoform) may preclude the correct folding of the complex with its cognate metal ion.

  4. 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.

  5. EFFECT OF METAL IONS ON THE LACCASE ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    XiwenWang; HuaiyuZhan; WeiHe

    2004-01-01

    The effects of five metal ions(Fe-'~,Ca-~*,Mg2*,Mn-'-"Cu2") on ABTS oxidation catalyzed by laccase werestudied under condition of pH=4.5 byspectrophotometer. The results show that Fe2+ ionhas obvious effect on the activity and the nature ofinhibition is competitive type. It is found that theinhibition is realized through the reduction ofABTS.by Fe2+ ion. Other metal ions have slight influence onlaccase activity.

  6. Phosphate Esters, Thiophosphate Esters and Metal Thiophosphates as Lubricant Additives

    Directory of Open Access Journals (Sweden)

    David W. Johnson

    2013-12-01

    Full Text Available Phosphate esters, thiophosphate esters and metal thiophosphates have been used as lubricant additives for over 50 years. While their use has been extensive, a detailed knowledge of how they work has been a much more recent development. In this paper, the use of phosphate esters and thiophosphate esters as anti-wear or extreme pressure additives is reviewed with an emphasis on their mechanism of action. The review includes the use of alkyl phosphates, triaryl phosphates and metal containing thiophosphate esters. The mechanisms of these materials interacting with a range of iron and steel based bearing material are examined.

  7. Controlled charge exchange between alkaline earth metals and their ions

    Science.gov (United States)

    Gacesa, Marko; Côté, Robin

    2015-05-01

    We theoretically investigate the prospects of realizing controlled charge exchange via magnetic Feshbach resonances in cold and ultracold collisions of atoms and ions. In particular, we focus on near-resonant charge exchange in heteroisotopic combinations of alkaline earth metals, such as 9Be++10 Be9 Be+10Be+ , which exhibit favorable electronic and hyperfine structure. The quantum scattering calculations are performed for a range of initial states and experimentally attainable magnetic fields in standard coupled-channel Feshbach projection formalism, where higher-order corrections such as the mass-polarization term are explicitely included. In addition, we predict a number of magnetic Feshbach resonances for different heteronuclear isotopic combinations of the listed and related alkaline earth elements. Our results imply that near-resonant charge-exchange could be used to realize atom-ion quantum gates, as well as controlled charge transfer in optically trapped cold quantum gases. This work is partially supported by ARO.

  8. DNA strand breakage by bivalent metal ions and ionizing radiation.

    Science.gov (United States)

    Ayene, Iraimoudi S; Koch, Cameron J; Krisch, Robert E

    2007-03-01

    To investigate mechanisms of DNA breakage via the interaction of bivalent metal ion, thiol reducing agent and ionizing radiation, in *OH scavenging abilities comparable to those in cells. We measured the effects of 10 min exposure to 200 microM Fe2+ vs. Fe3+ on the induction of single (SSB) and double (DSB) strand breaks in unirradiated and oxically irradiated SV40 DNA, in aqueous solution containing 75 or 750 mM glycerol and/or 5 mM glutathione (GSH). Fe2+ or GSH alone produced little DNA damage. However, their combination produced a dramatic increase in the production of both SSB and DSB. Experiments with ferric ion suggest that it produces DNA damage only after partial reduction to ferrous by GSH. Induction efficiencies for SSB in the presence of Fe2+/GSH showed additivity of the effects of radiation alone with those from Fe2+/GSH. However, the corresponding induction efficiencies for DSB demonstrated a 2.5-fold enhancement. Our results are consistent with a model in which reduced bivalent metal ions plus thiols, in the presence of O2, produce DSB in DNA primarily via local clusters of hydroxyl radicals arising from site specific Fenton reactions. The synergism observed between DSB production by Fe/GSH and by ionizing radiation, also believed to occur via local clusters of hydroxyl radicals, is consistent with this model. Our results suggest that both normally present intracellular iron and ionizing radiation may be important sources of oxidative stress in cells.

  9. The two distinctive metal ion binding domains of the wheat metallothionein Ec-1.

    Science.gov (United States)

    Peroza, Estevão A; Kaabi, Ali Al; Meyer-Klaucke, Wolfram; Wellenreuther, Gerd; Freisinger, Eva

    2009-03-01

    Metallothioneins are small cysteine-rich proteins believed to play a role, among others, in the homeostasis of essential metal ions such as Zn(II) and Cu(I). Recently, we could show that wheat E(c)-1 is coordinating its six Zn(II) ions in form of metal-thiolate clusters analogously to the vertebrate metallothioneins. Specifically, two Zn(II) ions are bound in the N-terminal and four in the C-terminal domain. In the following, we will present evidence for the relative independence of the two domains from each other with respect to their metal ion binding abilities, and uncover three intriguing peculiarities of the protein. Firstly, one Zn(II) ion of the N-terminal domain is relative resistant to complete replacement with Cd(II) indicating the presence of a Zn(II)-binding site with increased stability. Secondly, the C-terminal domain is able to coordinate an additional fifth metal ion, though with reduced affinity, which went undetected so far. Finally, reconstitution of apoE(c)-1 with an excess of Zn(II) shows a certain amount of sub-stoichiometrically metal-loaded species. The possible relevance of these finding for the proposed biological functions of wheat E(c)-1 will be discussed. In addition, extended X-ray absorption fine structure (EXAFS) measurements on both, the full-length and the truncated protein, provide final evidence for His participation in metal ion binding.

  10. 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.

  11. 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.

  12. Catalysis using hydrous metal oxide ion exchanges

    Science.gov (United States)

    Dosch, Robert G.; Stephens, Howard P.; Stohl, Frances V.

    1985-01-01

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  13. Catalysis using hydrous metal oxide ion exchangers

    Science.gov (United States)

    Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

    1983-07-21

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  14. Competing binding of metal ions with protein studied by microdialysis

    Institute of Scientific and Technical Information of China (English)

    GUO; Ming(郭明); KONG; Liang(孔亮); MAO; Xiqin(毛希琴); LI; Xin(历欣); ZOU; Hanfa(邹汉法)

    2002-01-01

    A method has been established to study the competing binding of metal ions with protein by a combined technique of microdialysis with high performance liquid chromatography (HPLC). Ni2+, Cd2+, Zn2+, Cu2+ and human serum albumin (HSA) were chosen as model metal ions and protein. The experimental results show that Ni2+ and Cu2+ share a common primary binding site on HSA, and Zn2+ and Cd2+ share a different common primary binding site from them, but there is a common multi-metal binding site for all of those four metal ions. This method show advantages of fast sampling, easily to be operated and especially to be useful when ideal spectroscopic probes are not available for the study of interaction between protein and metal ions.

  15. Accelerating Industrial Adoption of Metal Additive Manufacturing Technology

    Science.gov (United States)

    Vartanian, Kenneth; McDonald, Tom

    2016-03-01

    While metal additive manufacturing (AM) technology has clear benefits, there are still factors preventing its adoption by industry. These factors include the high cost of metal AM systems, the difficulty for machinists to learn and operate metal AM machines, the long approval process for part qualification/certification, and the need for better process controls; however, the high AM system cost is the main barrier deterring adoption. In this paper, we will discuss an America Makes-funded program to reduce AM system cost by combining metal AM technology with conventional computerized numerical controlled (CNC) machine tools. Information will be provided on how an Optomec-led team retrofitted a legacy CNC vertical mill with laser engineered net shaping (LENS®—LENS is a registered trademark of Sandia National Labs) AM technology, dramatically lowering deployment cost. The upgraded system, dubbed LENS Hybrid Vertical Mill, enables metal additive and subtractive operations to be performed on the same machine tool and even on the same part. Information on the LENS Hybrid system architecture, learnings from initial system deployment and continuing development work will also be provided to help guide further development activities within the materials community.

  16. Porosity Measurements and Analysis for Metal Additive Manufacturing Process Control.

    Science.gov (United States)

    Slotwinski, John A; Garboczi, Edward J; Hebenstreit, Keith M

    2014-01-01

    Additive manufacturing techniques can produce complex, high-value metal parts, with potential applications as critical metal components such as those found in aerospace engines and as customized biomedical implants. Material porosity in these parts is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants - since surface-breaking pores allows for better integration with biological tissue. Changes in a part's porosity during an additive manufacturing build may also be an indication of an undesired change in the build process. Here, we present efforts to develop an ultrasonic sensor for monitoring changes in the porosity in metal parts during fabrication on a metal powder bed fusion system. The development of well-characterized reference samples, measurements of the porosity of these samples with multiple techniques, and correlation of ultrasonic measurements with the degree of porosity are presented. A proposed sensor design, measurement strategy, and future experimental plans on a metal powder bed fusion system are also presented.

  17. 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

  18. Characterization of Metal Powders Used for Additive Manufacturing.

    Science.gov (United States)

    Slotwinski, J A; Garboczi, E J; Stutzman, P E; Ferraris, C F; Watson, S S; Peltz, M A

    2014-01-01

    Additive manufacturing (AM) techniques can produce complex, high-value metal parts, with potential applications as critical parts, such as those found in aerospace components. The production of AM parts with consistent and predictable properties requires input materials (e.g., metal powders) with known and repeatable characteristics, which in turn requires standardized measurement methods for powder properties. First, based on our previous work, we assess the applicability of current standardized methods for powder characterization for metal AM powders. Then we present the results of systematic studies carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to structure and chemistry, including X-ray diffraction, energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, and X-Ray photoelectron spectroscopy were also employed. The results of these analyses show how virgin powder changes after being exposed to and recycled from one or more Direct Metal Laser Sintering (DMLS) additive manufacturing build cycles. In addition, these findings can give insight into the actual additive manufacturing process.

  19. Bioinorganic Chemistry of the Alkali Metal Ions.

    Science.gov (United States)

    Kim, Youngsam; Nguyen, Thuy-Tien T; Churchill, David G

    2016-01-01

    The common Group 1 alkali metals are indeed ubiquitous on earth, in the oceans and in biological systems. In this introductory chapter, concepts involving aqueous chemistry and aspects of general coordination chemistry and oxygen atom donor chemistry are introduced. Also, there are nuclear isotopes of importance. A general discussion of Group 1 begins from the prevalence of the ions, and from a comparison of their ionic radii and ionization energies. While oxygen and water molecule binding have the most relevance to biology and in forming a detailed understanding between the elements, there is a wide range of basic chemistry that is potentially important, especially with respect to biological chelation and synthetic multi-dentate ligand design. The elements are widely distributed in life forms, in the terrestrial environment and in the oceans. The details about the workings in animal, as well as plant life are presented in this volume. Important biometallic aspects of human health and medicine are introduced as well. Seeing as the elements are widely present in biology, various particular endogenous molecules and enzymatic systems can be studied. Sodium and potassium are by far the most important and central elements for consideration. Aspects of lithium, rubidium, cesium and francium chemistry are also included; they help in making important comparisons related to the coordination chemistry of Na(+) and K(+). Physical methods are also introduced.

  20. Adsorption of rare earth metal ion by algae. Sorui ni yoru kidorui ion no kyuchaku

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, T.; Yazawa, A. (Miyagi National College of Technology, Miyagi (Japan))

    1994-02-25

    This paper reports the result of investigations on adsorption of rare earth metal ion by using algae, and adsorption of different metal ions by using egg white and soy bean protein. Rare earth metal ion is adsorbed at a considerably high rate with alga powder of different kinds. The adsorption has been judged to be cation exchange reactive adsorption, while with use of spirulina and chlorella a maximum value of adsorption rate has been observed at pH from 3 to 4.5. Therefore, selective adsorption and separation of metal ions other than rare earth metal ion has become possible. When the blue pigment extracted from spirulina, the spirulina blue, is used, the rare earth metal ion had its selective adsorption and separation performance improved higher than using spirulina itself at pH from 3 to 4.5. As a result of adsorption experiment using egg white and soy bean protein, it has been found that the metal ion adsorption behavior of the spirulina blue depends on coagulative action of protein structure to some extent. However, the sharp selective adsorption performance on rare earth metal ion due to particular pH strength has been found because of actions unique to the pigment structure of phycocyanin, a major component in the spirulina blue. 7 refs., 19 figs.

  1. Synthesis of Novel Metal Ion Sensors Based on DNA-Metal Interactions

    Institute of Scientific and Technical Information of China (English)

    Akira Ono; Shiqi Cao; Humika Togashi; Yoko Miyake

    2005-01-01

    @@ 1Introduction The interactions of metal ions with nucleic acids, nucleosides, and nucleo-bases have been extensively investigated[1,2]. We have reported that thymine-thymine (T-T) and cytosine-cytosine (C- C) miss base pairs in DNA duplexes highly selectively capture HgⅡ ion and Ag Ⅰ ion, which result in formations of metal-mediated base pairs, T-HgⅡ -T and C-AgⅠ -C, in duplexes[3]. The phenomenon is expected to be useful for a variety of studies such as synthesis of nano-wires containing metal ions, developing metal-ion sensing methods, etc.Here, we report novel oligodeoxyribonucleotide (ODN)-based sensors that detect HgⅡ ions and AgⅠ ions in aqueous solutions.

  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. 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.

  4. EFFECT OF METAL IONS ON THE LACCASE ACTIVITY

    Institute of Scientific and Technical Information of China (English)

    Xiwen Wang; Huaiyu Zhan; Wei He

    2004-01-01

    The effects of five metal ions(Fe2+、Ca2+、Mg2+、Mn2+、Cu2+) on ABTS oxidation catalyzed by laccase were studied under condition of pH=4.5 by spectrophotometer. The results show that Fe2+ ion has obvious effect on the activity and the nature of inhibition is competitive type. It is found that the inhibition is realized through the reduction ofABTS.by Fe2+ ion. Other metal ions have slight influence on laccase activity.

  5. Developing Gradient Metal Alloys through Radial Deposition Additive Manufacturing

    Science.gov (United States)

    Hofmann, Douglas C.; Roberts, Scott; Otis, Richard; Kolodziejska, Joanna; Dillon, R. Peter; Suh, Jong-ook; Shapiro, Andrew A.; Liu, Zi-Kui; Borgonia, John-Paul

    2014-01-01

    Interest in additive manufacturing (AM) has dramatically expanded in the last several years, owing to the paradigm shift that the process provides over conventional manufacturing. Although the vast majority of recent work in AM has focused on three-dimensional printing in polymers, AM techniques for fabricating metal alloys have been available for more than a decade. Here, laser deposition (LD) is used to fabricate multifunctional metal alloys that have a strategically graded composition to alter their mechanical and physical properties. Using the technique in combination with rotational deposition enables fabrication of compositional gradients radially from the center of a sample. A roadmap for developing gradient alloys is presented that uses multi-component phase diagrams as maps for composition selection so as to avoid unwanted phases. Practical applications for the new technology are demonstrated in low-coefficient of thermal expansion radially graded metal inserts for carbon-fiber spacecraft panels. PMID:24942329

  6. Developing gradient metal alloys through radial deposition additive manufacturing.

    Science.gov (United States)

    Hofmann, Douglas C; Roberts, Scott; Otis, Richard; Kolodziejska, Joanna; Dillon, R Peter; Suh, Jong-ook; Shapiro, Andrew A; Liu, Zi-Kui; Borgonia, John-Paul

    2014-06-19

    Interest in additive manufacturing (AM) has dramatically expanded in the last several years, owing to the paradigm shift that the process provides over conventional manufacturing. Although the vast majority of recent work in AM has focused on three-dimensional printing in polymers, AM techniques for fabricating metal alloys have been available for more than a decade. Here, laser deposition (LD) is used to fabricate multifunctional metal alloys that have a strategically graded composition to alter their mechanical and physical properties. Using the technique in combination with rotational deposition enables fabrication of compositional gradients radially from the center of a sample. A roadmap for developing gradient alloys is presented that uses multi-component phase diagrams as maps for composition selection so as to avoid unwanted phases. Practical applications for the new technology are demonstrated in low-coefficient of thermal expansion radially graded metal inserts for carbon-fiber spacecraft panels.

  7. 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.

  8. Importance of diffuse metal ion binding to RNA.

    Science.gov (United States)

    Tan, Zhi-Jie; Chen, Shi-Jie

    2011-01-01

    RNAs are highly charged polyanionic molecules. RNA structure and function are strongly correlated with the ionic condition of the solution. The primary focus of this article is on the role of diffusive ions in RNA folding. Due to the long-range nature of electrostatic interactions, the diffuse ions can contribute significantly to RNA structural stability and folding kinetics. We present an overview of the experimental findings as well as the theoretical developments on the diffuse ion effects in RNA folding. This review places heavy emphasis on the effect of magnesium ions. Magnesium ions play a highly efficient role in stabilizing RNA tertiary structures and promoting tertiary structural folding. The highly efficient role goes beyond the mean-field effect such as the ionic strength. In addition to the effects of specific ion binding and ion dehydration, ion-ion correlation for the diffuse ions can contribute to the efficient role of the multivalent ions such as the magnesium ions in RNA folding.

  9. METAL ION SORPTION TO BIRCH AND SPRUCE WOOD

    Directory of Open Access Journals (Sweden)

    Pingping Su,

    2012-02-01

    Full Text Available Sorption of metal ions from aqueous solutions to birch wood and spruce heartwood and sapwood has been studied. Functional groups in wood were determined by acid-base titrations. The sorption of metal ions to wood of the different tree species was investigated by a column chromatographic technique. The mechanism of sorption is mainly ion exchange by complexation of metal ions to the functional groups, e.g. carboxyl groups and phenolic hydroxyl groups, in the wood phase. By combination of the sorption experiments with four different metal ion mixtures, the following affinity order was established for spruce sapwood particles: Fe3+>>Pb2+>>Cu2+>>Fe2+>Cd2+>Zn2+>Ni2+>Mn2+≥Ca2+≥Sr2+≥Ba2+>>Mg2+>>K+>Na+≈Li+. For all three types of stemwood studied, the affinity orders were almost the same. The ion exchange properties of wood were comparable to those of a weakly acid cation exchanger. The affinity order obtained for the synthetic resin was quite similar to the order given above for wood. The metal sorption properties of wood materials imply that they could be a potential material for removal of metal ions from aqueous solutions.

  10. 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.

  11. 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.

  12. Antimicrobial Effect of Metal Ions Substitution to HAp, Zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. J.; Kim, S. B.; Cho, S. B; Cho, K. J.; Lee, T. H. [Pai Chai University, Taejeon (Korea); Kim, T. N. [Korea Institute of Geoscience and Mineral Resources, Taejeon (Korea)

    2001-02-01

    Generally, hydroxyapatite(HAp), zeolite, carbon molecular sieve, activated carbon and alumina are used as heavy metal ions adsorption materials. Among those adsorption materials, HAp which has good positive ion-exchange ability with metal ion, and zeolite are utilized in wastewater treatment. Most of water pollutions are caused by hazardous heavy metals ions as well as bacteria in waste water. In this study, a adsorption materials (HAp and zeolite) are ion-exchanged with a well known antimicrobial metal ions, such as Ag{sup +}, Cu{sup 2+}, and Zn{sup 2+}, in order to give a adsorption of heavy metal ions and a killing effects of bacteria. The antimicrobial effects of adsorption materials are observed using by E. Coli. The results show that there is a complete antimicrobial effect in the adsorption materials with Ag{sup +} at the concentration of 1x10{sup -4}cell/ml of E. Coli until 24 hours. However, there is not good antimicrobial effects in the adsorption materials with Cu{sup 2+} and Zn{sup 2+} substitution. Feng et. al. showed the denaturation effects of silver ions which induces the condensed DNA molecules and losing their replication abilities. (author). 13 refs., 6 figs., 2 tabs.

  13. 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.

  14. A Study of Metal-Cement Composites with Additives

    Directory of Open Access Journals (Sweden)

    Mironov Victor

    2014-12-01

    Full Text Available The application of small-sized metal fillers (SMF provides a combination of high bulk density, increased durability and ferromagnetic properties of composite materials on the cement basis. However, the total strength of the composite can be compromised by poor adhesion of metal particles with the cement matrix. The use of versatile additives like microsilica and metakaolin is able to improve the structural integrity and mechanical properties of heavy concretes. The paper considers the results of a study using specimens of heavy concretes with SMF aiming to estimate its strength, structural features and ultrasonic parameters. It was found that the contact of SMF particles with the cement was not perfect, since the voids appeared between them and the cement matrix during the cement hydration process (exothermal reaction. Due to the border porosity, the specimens with the metal fillers have lower compressive strength, lower ultrasound velocity and increased frequency slope of attenuation. Microsilica and metakaolin additives facilitate better contact zone between the cement matrix and metal fillers.

  15. Experimental Study on Surface Reactions of Heavy Metal Ions With Quartz—Aqueous Ion Concentration Dependence

    Institute of Scientific and Technical Information of China (English)

    吴宏海; 吴大清; 等

    1999-01-01

    Adsorption of divalent metal ions,including Cu2+,Pb2+,Zn2+,Cd2+ and Ni2+,on quartz surface was measured as a function of metal ion concentration at 30℃under condi tions of solution pH=6.5 and ion strength I=0.1mol/L.Results of the experimental measuements can be described very well by adsorption isoterm dquations of Freudlich.The correlation coefficients(r)of adsorption isotherm lines are>0.96.Moreover,the exprimental data were interpreted on the basis of surface complexation model.Te experimental results showed that the monodentate-coordinated metal ion surface complex species(SOM+)are predominant over the bidentate-coordinated metal ion surface complex species[(SO)2M]formed only by the ions Cu2+,Zn2+ and Ni2+,And the relevant apparent surface complexation constants are lgKM=2.2-3.3 in order of KCd≥KPb>KZn>KNi≥KCu,and lgβM=5.8-6.8 in oder of βNi>βZn>βCu.Therefore,the reactive ability of the ions onto mineral surface of quartz follows the order of Cd>Pb>Zn>Ni>Cu under the above-mentioned solution conditions.The apparent surface complexation constants,influenced by the surface potential,surface species and hydrolysis of metal ions,depend mainly on the Born solvation coefficeient of the metal ions.

  16. Heavy ion time-of-flight ERDA of high dose metal implanted germanium

    Energy Technology Data Exchange (ETDEWEB)

    Dytlewski, N.; Evans, P.J.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Bunder, J. [New South Wales Univ., Wollongong, NSW (Australia). Wollongong Univ. Coll

    1996-12-31

    With the thick Ge substrates used in ion implantation, RBS can have difficulty in resolving the mass-depth ambiguities when analysing materials composed of mixtures of elements with nearly equal masses. Additional, and complimentary techniques are thus required. This paper reports the use of heavy ion time-of-flight elastic recoil detection analysis (ToF- ERDA), and conventional RBS in the analysis of Ge(100) implanted with high dose Ti and Cu ions from a MEWA ion source . Heavy ion ToF ERDA has been used to resolve, and profile the implanted transition metal species, and also to study any oxygen incorporation into the sample resulting from the implantation, or subsequential reactions with air or moisture. This work is part of a study on high dose metal ion implantation of medium atomic weight semiconductor materials. 13 refs., 6 figs.

  17. Kinetic Analysis of Metal Ions: An Undergraduate Laboratory Experiment.

    Science.gov (United States)

    Williams, Kathryn R.

    1985-01-01

    Reports on the adaptation of a kinetic method of analysis of metal ions for use in an undergraduate teaching laboratory. Background information, procedures used, and analysis of typical results obtained are provided. (JN)

  18. Electron Capture Dissociation of Trivalent Metal Ion-Peptide Complexes

    National Research Council Canada - National Science Library

    Flick, Tawnya G; Donald, William A; Williams, Evan R

    2013-01-01

    .... ECD of these doubly charged complexes containing MT results in significantly higher electron capture efficiency and sequence coverage than peptide-divalent metal ion complexes that have the same net charge...

  19. COORDINATION OF CASSAVA STARCH TO METAL IONS AND ...

    African Journals Online (AJOL)

    a

    Soc. Ethiop. 2003, 17(2), 155-165. ISSN 1011-3924 ... Cassava starch formed Werner-type complexes with ions of metals from the transition groups. This was proven by conductivity and electron paramagnetic resonance measurements.

  20. Applications for Gradient Metal Alloys Fabricated Using Additive Manufacturing

    Science.gov (United States)

    Hofmann, Douglas C.; Borgonia, John Paul C.; Dillon, Robert P.; Suh, Eric J.; Mulder, jerry L.; Gardner, Paul B.

    2013-01-01

    Recently, additive manufacturing (AM) techniques have been developed that may shift the paradigm of traditional metal production by allowing complex net-shaped hardware to be built up layer-by-layer, rather than being machined from a billet. The AM process is ubiquitous with polymers due to their low melting temperatures, fast curing, and controllable viscosity, and 3D printers are widely available as commercial or consumer products. 3D printing with metals is inherently more complicated than with polymers due to their higher melting temperatures and reactivity with air, particularly when heated or molten. The process generally requires a high-power laser or other focused heat source, like an electron beam, for precise melting and deposition. Several promising metal AM techniques have been developed, including laser deposition (also called laser engineered net shaping or LENS® and laser deposition technology (LDT)), direct metal laser sintering (DMLS), and electron beam free-form (EBF). These machines typically use powders or wire feedstock that are melted and deposited using a laser or electron beam. Complex net-shape parts have been widely demonstrated using these (and other) AM techniques and the process appears to be a promising alternative to machining in some cases. Rather than simply competing with traditional machining for cost and time savings, the true advantage of AM involves the fabrication of hardware that cannot be produced using other techniques. This could include parts with "blind" features (like foams or trusses), parts that are difficult to machine conventionally, or parts made from materials that do not exist in bulk forms. In this work, the inventors identify that several AM techniques can be used to develop metal parts that change composition from one location in the part to another, allowing for complete control over the mechanical or physical properties. This changes the paradigm for conventional metal fabrication, which relies on an

  1. Metal Ion Selectivity of Kojate Complexes: A Theoretical Study

    Directory of Open Access Journals (Sweden)

    Sarita Singh

    2013-01-01

    Full Text Available Density functional calculations have been performed on four-coordinate kojate complexes of selected divalent metal ions in order to determine the affinity of the metal ions for the kojate ion. The complexation reactions are characterized by high energies, showing that they are highly exothermic. It is found that Ni(II exhibits the highest affinity for the kojate ion, and this is attributed to the largest amount of charge transfer from the ligand to the metal ion. The Ni(II complex has distorted square planar structure. The HOMOs and LUMOs of the complexes are also discussed. All complexes display a strong band at ~1500 cm−1 corresponding to the stretching frequency of the weakened carbonyl bond. Comparison of the complexation energies for the two steps shows that most of the complexation energy is realized in the first step. The energy released in the second step is about one-third that of the first step.

  2. Smart textile device using ion polymer metal compound.

    Science.gov (United States)

    Nakamura, Taro; Ihara, Tadashi

    2013-01-01

    We have developed a smart textile device that detects angular displacement of attached surface using ion polymer metal compound. The device was composed of ion polymer metal compound (IPMC) which was fabricated from Nafion resin by heat-press and chemical gold plating. The generated voltage from IPMC was measured as a function of bending angle. Fabricated IPMC device was weaved into a cotton cloth and multidirectional movements were detected.

  3. Isothermal Titration Calorimetry Measurements of Metal Ions Binding to Proteins.

    Science.gov (United States)

    Quinn, Colette F; Carpenter, Margaret C; Croteau, Molly L; Wilcox, Dean E

    2016-01-01

    ITC measurements involving metal ions are susceptible to a number of competing reactions (oxidation, precipitation, and hydrolysis) and coupled reactions involving the buffer and protons. Stabilization and delivery of the metal ion as a well-defined and well-characterized complex with the buffer, or a specific ligand, can suppress undesired solution chemistry and, depending on the stability of the metal complex, allow accurate measurements of higher affinity protein-binding sites. This requires, however, knowledge of the thermodynamics of formation of the metal complex and accounting for its contribution to the experimentally measured values (KITC and ΔHITC) through a post hoc analysis that provides the condition-independent binding thermodynamics (K, ΔG(o), ΔH, ΔS, and ΔCP). This analysis also quantifies the number of protons that are displaced when the metal ion binds to the protein. © 2016 Elsevier Inc. All rights reserved.

  4. Erosion yield of metal surface under ion pulsed irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Krivobokov, Valery; Stepanova, Olga, E-mail: omsa@tpu.ru; Yuryeva, Alena

    2013-11-15

    The paper is devoted to the study of erosion processes on a metal surface (Ag, Ni, Cu, W) under argon ion bombardment. The erosion yields including the sputtered and evaporated particles have been calculated for a wide range of the initial ion energy (1–1000 keV). They are revealed to reach the values from units to 10{sup 4} atom/ion under a pulsed ion beam with the power density of 10{sup 2}–10{sup 10} W/cm{sup 2}. The ion beam and target parameters are shown to influence on the erosion intensity.

  5. Functional identification of catalytic metal ion binding sites within RNA.

    Directory of Open Access Journals (Sweden)

    James L Hougland

    2005-09-01

    Full Text Available The viability of living systems depends inextricably on enzymes that catalyze phosphoryl transfer reactions. For many enzymes in this class, including several ribozymes, divalent metal ions serve as obligate cofactors. Understanding how metal ions mediate catalysis requires elucidation of metal ion interactions with both the enzyme and the substrate(s. In the Tetrahymena group I intron, previous work using atomic mutagenesis and quantitative analysis of metal ion rescue behavior identified three metal ions (MA, MB, and MC that make five interactions with the ribozyme substrates in the reaction's transition state. Here, we combine substrate atomic mutagenesis with site-specific phosphorothioate substitutions in the ribozyme backbone to develop a powerful, general strategy for defining the ligands of catalytic metal ions within RNA. In applying this strategy to the Tetrahymena group I intron, we have identified the pro-SP phosphoryl oxygen at nucleotide C262 as a ribozyme ligand for MC. Our findings establish a direct connection between the ribozyme core and the functionally defined model of the chemical transition state, thereby extending the known set of transition-state interactions and providing information critical for the application of the recent group I intron crystallographic structures to the understanding of catalysis.

  6. Metal Additive Manufacturing: A Review of Mechanical Properties

    Science.gov (United States)

    Lewandowski, John J.; Seifi, Mohsen

    2016-07-01

    This article reviews published data on the mechanical properties of additively manufactured metallic materials. The additive manufacturing techniques utilized to generate samples covered in this review include powder bed fusion (e.g., EBM, SLM, DMLS) and directed energy deposition (e.g., LENS, EBF3). Although only a limited number of metallic alloy systems are currently available for additive manufacturing (e.g., Ti-6Al-4V, TiAl, stainless steel, Inconel 625/718, and Al-Si-10Mg), the bulk of the published mechanical properties information has been generated on Ti-6Al-4V. However, summary tables for published mechanical properties and/or key figures are included for each of the alloys listed above, grouped by the additive technique used to generate the data. Published values for mechanical properties obtained from hardness, tension/compression, fracture toughness, fatigue crack growth, and high cycle fatigue are included for as-built, heat-treated, and/or HIP conditions, when available. The effects of test orientation/build direction on properties, when available, are also provided, along with discussion of the potential source(s) (e.g., texture, microstructure changes, defects) of anisotropy in properties. Recommendations for additional work are also provided.

  7. 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 ... nickel(lI) ion whose chemistry is a reasonable substitute for many of the common environmentally .... certain soil bacteria secrete powerful.

  8. Polaronic Transport in Phosphate Glasses Containing Transition Metal Ions

    Science.gov (United States)

    Henderson, Mark

    The goal of this dissertation is to characterize the basic transport properties of phosphate glasses containing various amounts of TIs and to identify and explain any electronic phase transitions which may occur. The P2 O5-V2O5-WO3 (PVW) glass system will be analyzed to find the effect of TI concentration on conduction. In addition, the effect of the relative concentrations of network forming ions (SiO2 and P2O5) on transport will be studied in the P2O5-SiO2-Fe2O 3 (PSF) system. Also presented is a numerical study on a tight-binding model adapted for the purposes of modelling Gaussian traps, mimicking TI's, which are arranged in an extended network. The results of this project will contribute to the development of fundamental theories on the electronic transport in glasses containing mixtures of transition oxides as well as those containing multiple network formers without discernible phase separation. The present study on the PVW follows up on previous investigation into the effect on mixed transition ions in oxide glasses. Past research has focused on glasses containing transition metal ions from the 3d row. The inclusion of tungsten, a 5d transition metal, adds a layer of complexity through the mismatch of the energies of the orbitals contributing to localized states. The data have indicated that a transition reminiscent of a metal-insulator transition (MIT) occurs in this system as the concentration of tungsten increases. As opposed to some other MIT-like transitions found in phosphate glass systems, there seems to be no polaron to bipolaron conversion. Instead, the individual localization parameter for tungsten noticeably decreases dramatically at the transition point as well as the adiabaticity. Another distinctive feature of this project is the study of the PSF system, which contains two true network formers, phosphorous pentoxide (P2O 5) and silicon dioxide (SiO2). It is not usually possible to do a reliable investigation of the conduction properties of

  9. ADDITION OF ELECTRIC ARC FURNACE DUST IN HOT METAL

    Directory of Open Access Journals (Sweden)

    Felipe Fardin Grillo

    2013-03-01

    Full Text Available This research aims to study the process of incorporation of the mass in final hot metal and volatilization mass contained in the electric arc furnace dust (EAFD, by addition in hot metal at a temperature of 1,400°C; 1,450°C and 1,500°C altering experimental conditions such as the percentage of EAFD to be added and the percentage of silicon in hot metal. Previously, the EAFD was characterized using techniques of chemical analysis and size analysis. After characterization, the EAFD to be added to the hot metal was agglomerated in the form of briquettes. The achievement of fusion experiments in laboratory scale was placed in a vertical tubular furnace with temperature control. A flow of inert gas (argon was maintained inside the furnace during the experiments. The result of the sample EAFD volatilized shows that there is an increase in the zinc concentration when compared with the concentration of zinc present in EAFD “as received”.

  10. The use of ion flotation for detoxification of metal-contaminated waters and process effluents

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, F.M.; Duyvesteyn, S.; Sreenivasarao, K. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1995-12-31

    Toxic metals entering surface or ground water from sources such as metal finishing shop spills and abandoned mines can pose a significant threat to public health and the environment. Ion flotation and similar foam separation techniques show great promise for treating dilute, metal-contaminated solutions, and could also be used to treat effluents from many minerals and metallurgical processing operations prior to discharge. In ion flotation, an appropriate collector is added to the solution to form hydrophobic complexes with the metal ions. These metal-bearing species are then removed by flotation, usually with trace addition of a frother to stabilize the foam. In an effort to better understand the underlying scientific and engineering principles that determine the performance of ion flotation, the removal of Cu(II), Pb(II), Cd(II), Cr(III) and Cr(VI) has been studied using laboratory scale flotation columns in batch mode. The effects of the superficial air velocity, solution and froth height, nature of the collector, collector:metal-ion ratio, ionic strength and several frothers at low concentrations on the flotation kinetics are reported. Finally, results are presented on methods that might allow regeneration of collector and recovery of by-product metal from the foam product.

  11. 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.

  12. Towards metals analysis using corona discharge ionization ion mobility spectrometry.

    Science.gov (United States)

    Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

    2016-02-25

    For the first time, the capability of corona discharge ionization ion mobility spectrometry (CD-IMS) in the determination of metal complex was evaluated. The extreme simplicity of dispersive liquid-liquid microextraction (DLLME) coupled to the high sensitivity of CD-IMS measurement could make this combination really useful for simple, rapid, and sensitive determination of metals in different samples. In this regard, mercury, as a model metal, was complexed with diethyldithiocarbamate (DEDTC), and then extracted into the carbon tetrachloride using DLLME. Some parameters affecting the extraction efficiency, including the type and volume of the extraction solvent, the type and volume of the disperser solvent, the concentration of the chelating agent, salt addition and, pH were exhaustively investigated. Under the optimized condition, the enrichment factor was obtained to be 142. The linear range of 0.035-10.0 μg mL(-1) with r(2) = 0.997 and the detection limit of 0.010 μg mL(-1) were obtained. The relative standard deviation values were calculated to be lower than 4% and 8% for intra-day and inter-day, respectively. Finally, the developed method was successfully applied for the extraction and determination of mercury in various real samples. The satisfactory results revealed the capability of the proposed method in trace analysis without tedious derivatization or hydride generation.

  13. Structure of metal matrix composites with an addition of tuff

    Directory of Open Access Journals (Sweden)

    M. Łach

    2010-07-01

    Full Text Available The article presents preliminary results of tests of metal matrix composites structure which was modified by an addition of powderedvolcanic tuff. Distribution and shape of ceramic particles as well as the quality of the bonding along the tuff- metal matrix interface werestudied. Depth of tuff element diffusion in the matrix as well as diffusion in tuff particles were checked. Micro-hardness and porosity of the composites were also tested. The tuff from Filipowice near the town of Krzeszowice was used for the tests. Powder metallurgy wasapplied to obtain the composites and the matrix materials were copper and 316L steel powders. The tuff was introduced in 2, 5 and 10 %by weight. To remove water from the channels of aluminosilicates, the tuff was baked at 850 oC for 4 hours and then cooled together withthe oven. The tests revealed good quality of the bonding of the tuff particles and the matrix and their even distribution. The addition of tuff improved the hardness of the composites and reduced their porosity which has great significance because of possible applications of this kind of materials in general and copper composites in particular. This gives grounds for further studies on volcanic tuff use in metal composites

  14. The influence of primary ion bombardment conditions on the secondary ion emission behavior of polymer additives

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, R.; Hagenhoff, B.; Pijpers, P.; Verlaek, R

    2003-01-15

    The secondary ion (SI) emission behavior of pure polymer systems is meanwhile well understood. However, common plastics not only consist of the polymer host material but also contain a variety of additives normally present in low concentrations only. In order to better understand the parameters governing the SI emission of these trace compounds we performed a systematic study on the influence of the analysis parameters (primary ion (PI) type, PI energy, electron bombardment for charge compensation, etc.) using model systems. Samples were prepared by spin coating (sub)monolayers of Irganox 1010 onto additive-free low density polyethylene (LDPE). The SI parameters yield, disappearance cross-section and efficiency (yield per damaged area) were determined for PI bombardment with Ga{sup +}, Cs{sup +}, and SF{sub 5}{sup +}. Furthermore the damaging influence of electron bombardment for charge compensation on the organic surface layers was investigated.

  15. The influence of primary ion bombardment conditions on the secondary ion emission behavior of polymer additives

    Science.gov (United States)

    Kersting, R.; Hagenhoff, B.; Pijpers, P.; Verlaek, R.

    2003-01-01

    The secondary ion (SI) emission behavior of pure polymer systems is meanwhile well understood. However, common plastics not only consist of the polymer host material but also contain a variety of additives normally present in low concentrations only. In order to better understand the parameters governing the SI emission of these trace compounds we performed a systematic study on the influence of the analysis parameters (primary ion (PI) type, PI energy, electron bombardment for charge compensation, etc.) using model systems. Samples were prepared by spin coating (sub)monolayers of Irganox 1010 onto additive-free low density polyethylene (LDPE). The SI parameters yield, disappearance cross-section and efficiency (yield per damaged area) were determined for PI bombardment with Ga +, Cs +, and SF 5+. Furthermore the damaging influence of electron bombardment for charge compensation on the organic surface layers was investigated.

  16. Metal ion trend may be more predictive for malfunctioning metal-on-metal implants than a single measurement

    NARCIS (Netherlands)

    Smolders, J.M.; Hol, A.; Susante, J.L.C. van

    2013-01-01

    Forty-eight unilateral hip resurfacing arthroplasty patients were evaluated for cobalt and chromium levels. The metal ion trend of 42 well-functioning patients was compared with six sub-optimal functioning patients. Median metal ion levels were significantly higher for the sub-optimal group. For the

  17. Laser Assisted Additively Manufactured Transition Metal Coating on Aluminum

    Science.gov (United States)

    Vora, Hitesh D.; Rajamure, Ravi Shanker; Roy, Anurag; Srinivasan, S. G.; Sundararajan, G.; Banerjee, Rajarshi; Dahotre, Narendra B.

    2016-07-01

    Various physical and chemical properties of surface and subsurface regions of Al can be improved by the formation of transition metal intermetallic phases (Al x TM y ) via coating of the transition metal (TM). The lower equilibrium solid solubility of TM in Al (laser-aided additive manufacturing approach can effectively synthesize TM intermetallic coatings on the surface of Al. The focus of the present work included the development of process control to achieve thermodynamic and kinetic conditions necessary for desirable physical, microstructural and compositional attributes. A multiphysics finite element model was developed to predict the temperature profile, cooling rate, melt depth, dilution of W in Al matrix and corresponding micro-hardness in the coating, and the interface between the coating and the base material and the base material.

  18. Complex metallic alloys as new materials for additive manufacturing.

    Science.gov (United States)

    Kenzari, Samuel; Bonina, David; Marie Dubois, Jean; Fournée, Vincent

    2014-04-01

    Additive manufacturing processes allow freeform fabrication of the physical representation of a three-dimensional computer-aided design (CAD) data model. This area has been expanding rapidly over the last 20 years. It includes several techniques such as selective laser sintering and stereolithography. The range of materials used today is quite restricted while there is a real demand for manufacturing lighter functional parts or parts with improved functional properties. In this article, we summarize recent work performed in this field, introducing new composite materials containing complex metallic alloys. These are mainly Al-based quasicrystalline alloys whose properties differ from those of conventional alloys. The use of these materials allows us to produce light-weight parts consisting of either metal-matrix composites or of polymer-matrix composites with improved properties. Functional parts using these alloys are now commercialized.

  19. Additive manufacturing of metals the technology, materials, design and production

    CERN Document Server

    Yang, Li; Baughman, Brian; Godfrey, Donald; Medina, Francisco; Menon, Mamballykalathil; Wiener, Soeren

    2017-01-01

    This book offers a unique guide to the three-dimensional (3D) printing of metals. It covers various aspects of additive, subtractive, and joining processes used to form three-dimensional parts with applications ranging from prototyping to production. Examining a variety of manufacturing technologies and their ability to produce both prototypes and functional production-quality parts, the individual chapters address metal components and discuss some of the important research challenges associated with the use of these technologies. As well as exploring the latest technologies currently under development, the book features unique sections on electron beam melting technology, material lifting, and the importance this science has in the engineering context. Presenting unique real-life case studies from industry, this book is also the first to offer the perspective of engineers who work in the field of aerospace and transportation systems, and who design components and manufacturing networks. Written by the leadin...

  20. In Vivo Metal Ion Imaging Using Fluorescent Sensors.

    Science.gov (United States)

    Van de Bittner, Genevieve C; Hirayama, Tasuku

    2016-01-01

    In vivo imaging in living animals provides the ability to monitor alterations of signaling molecules, ions, and other biological components during various life stages and in disease. The data gained from in vivo imaging can be used for biological discovery or to determine elements of disease progression and can inform the development and translation of therapeutics. Herein, we present theories behind small-molecule, fluorescent, metal ion sensors as well as the methods for their successful application to in vivo metal ion imaging, including ex vivo validation.

  1. 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.

  2. Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

    Science.gov (United States)

    Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

    2016-06-01

    Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials.

  3. THE THEORETICAL STUDY OF ADSORPTION OF METAL IONS ON CHITOSAN

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The interactions between metal ions such as Zn2+, Pb2+, Mn2+, Hg2+, Cd2+, Ni2+ and chitosan have been investigated using the model cluster model method and density functional method. Full optimization and frequency analysis of all cluster models have been performed employing B3LYP hybrid method at 3-21G basis set level except metal ions which were invoked to use effective core potential (ECP) method. The energy changes, and the main structural parameters have been obtained during the theoretical study of the adsorption of metal ions on the chitosan. The calculations showed that the coordination modes of metal ions with chitosan models were different, the geometries of Mn2+, Zn2+, Cd2+, Hg2+, Pb2+ ions coordinated with two nitrogen atoms and two oxygen atoms were distorted tetrahedral, while the square planar structure of Ni2+ coordinated two nitrogen atoms and two oxygen atoms was observed. The heat of reaction between six metal ions and chitosan models showed the order: Mn2+ >Ni2+ >Zn2+ >Pb2+ >Hg2+ >Cd2+, this suggested that the coordination strength of Mn2+ >Ni2+ >Zn2+ >Pb2+ >Hg2+ >Cd2+.

  4. Hall transport of divalent metal ion modified DNA lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dugasani, Sreekantha Reddy; Lee, Keun Woo; Yoo, Sanghyun; Gnapareddy, Bramaramba; Bashar, Saima; Park, Sung Ha, E-mail: sunghapark@skku.edu [Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Si Joon; Jung, Joohye; Jung, Tae Soo; Kim, Hyun Jae, E-mail: hjk3@yonsei.ac.kr [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2015-06-29

    We investigate the Hall transport characteristics of double-crossover divalent metal ion (Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+})-modified DNA (M-DNA) lattices grown on silica via substrate-assisted growth. The electronic characteristics of the M-DNA lattices are investigated by varying the concentration of the metal ions and then conducting Hall measurements, including resistivity, Hall mobility, carrier concentration, and magneto resistance. The tendency of the resistivity and Hall mobility was to initially decrease as the ion concentration increased, until reaching the saturation concentration (C{sub s}) of each metal ion, and then to increase as the ion concentration increased further. On the other hand, the carrier concentration revealed the opposite tendency as the resistivity and Hall mobility. The specific binding (≤C{sub s}) and the nonspecific aggregates (>C{sub s}) of the ions into the DNA lattices were significantly affected by the Hall characteristics. The numerical ranges of the Hall parameters revealed that the M-DNA lattices with metal ions had semiconductor-like characteristics. Consequently, the distinct characteristics of the electrical transport through M-DNA lattices will provide useful information on the practical use of such structures in physical devices and chemical sensors.

  5. A vacuum spark ion source: High charge state metal ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Nikolaev, A. G.; Frolova, V. P. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Oks, E. M. [High Current Electronics Institute, Siberian Branch of the Russian Academy of Science, Tomsk 634055 (Russian Federation); Tomsk State University of Control System and Radioelectronics, Tomsk 634050 (Russian Federation)

    2016-02-15

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  6. A vacuum spark ion source: High charge state metal ion beams

    Science.gov (United States)

    Yushkov, G. Yu.; Nikolaev, A. G.; Oks, E. M.; Frolova, V. P.

    2016-02-01

    High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less than 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.

  7. Synthesis and Characteristics of A Novel Heavy Metal Ions Chelator

    Institute of Scientific and Technical Information of China (English)

    LIU Zhuannian; SONG Yejing; HAN Xiaogang

    2012-01-01

    Polyacrylamide-urea-sulfanilamide(PUS) was prepared as a novel heavy metal ions chelator and successfully used to simultaneously remove heavy metals from wastewater effluents.The effects of reaction parameters (sodium hydroxide,material ratio,temprature and contact time) were monitored to specify the best synthesis conditions.PUS was chemically characterized by means of infrared spectroscopy (FTIR) and ultraviolet-visible (UV-Vis).The simultaneous chelation performance of PUS towards selected heavy metals ions,Ni2+,Cu2+,Pb2+,Zn2+,Cd2+ was discussed,showing that Ni2+,Cu2+,Pb2+,Zn2+ could be better chelated.It is indicated that the synthesized PUS is a potential remediation material when used for the treatment of wastewater containing metal ions.

  8. 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.

  9. Additively manufactured metallic porous biomaterials based on minimal surfaces

    DEFF Research Database (Denmark)

    Bobbert, F. S. L.; Lietaert, K.; Eftekhari, Ali Akbar

    2017-01-01

    Porous biomaterials that simultaneously mimic the topological, mechanical, and mass transport properties of bone are in great demand but are rarely found in the literature. In this study, we rationally designed and additively manufactured (AM) porous metallic biomaterials based on four different...... transport properties. The topology of the developed biomaterials resembles that of trabecular bone including a mean curvature close to zero. Moreover, the developed biomaterials show an unusual combination of low elastic modulus to avoid stress shielding and high strength to provide mechanical support...

  10. Effect of Copper Addition on Electromigration Behavior of Silver Metallization

    Science.gov (United States)

    Bhagat, Shekhar; Theodore, N. David; Chenna, Santhosh; Alford, Terry

    2009-09-01

    This study investigates the effect of Cu alloying on electromigration behavior of Ag metallization. Electromigration tests are performed on pure Ag and Ag (1.5% Cu) samples deposited by e-beam evaporation. The experiments show that Ag (Cu) alloy interconnect has superior elctromigration resistance compared to pure Ag interconnect. X-ray diffraction, four point probe measurements and electron microscopy were used to investigate the test structures and corresponding thin film samples. The Cu improves the lifetime of interconnect test structures by hindering Ag diffusion and increasing 111 texture of Ag. Also, Cu addition seemingly reduces the agglomeration in Ag.

  11. Property enchancement of polyimide films by way of the incorporation of lanthanide metal ions

    Science.gov (United States)

    Thompson, David W.

    1993-01-01

    Lanthanide metal ions were incorporated into the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 1,3-bis(aminophenoxy) benzene (APB) in an attempt to produce molecular level metal-polymer composites. The lanthanide series of metal ions (including aluminum, scandium, and yttrium) provide discrete and stable metal ions in the 3+ oxidation state. Throughout the series there is a uniform variation in ionic size ranging from 50 pm for aluminum to a maximum of 103.4 pm for cerium and gradually decreasing again to 84.8 pm for lutetium. The high charge-to-size ratio for these ions as well as the ability to obtain large coordination numbers makes them excellent candidates for interacting with the polymer substructure. The distinct lack of solubility of simple lanthanide salts such as the acetates and halides has made it difficult to obtain metal ions distributed in the polymer framework as discrete ions or metal complexes rather than microcomposites of metal clusters. (Lanthanum nitrates are quite soluble, but the presence of the strongly oxidizing nitrate ion leads to serious degradation of the polymer upon thermal curing. This work was successful at extending the range of soluble metals salts by using chelating agents derived from the beta-diketones dipivaloylmethane, dibenzoylmethane, trifluoroacetylacetone, and hexafluoroacetylacetone. Metal acetates which are insoluble in dimethylacetamide dissolve readily in the presence of the diketones. Addition of the polyimide yields a homogeneous resin which is then cast into a clear film. Upon curing clear films were obtained with the dibenzoylmethane and trifluoroacetylacetone ligands. The dipavaloylmethane precipitates the metal during the film casting process, and hexafluoroacetylacetone gives cured films which are deformed and brittle. These clear films are being evaluated for the effect of the metal ions on the coefficient of thermal expansion, resistance to atomic oxygen, and on

  12. Therapeutic redistribution of metal ions to treat Alzheimer's disease.

    Science.gov (United States)

    Crouch, Peter J; Barnham, Kevin J

    2012-09-18

    Currently, therapeutics that modify Alzheimer's disease (AD)are not available. Increasing age is the primary risk factor for AD and due to an aging global population the urgent need for effective therapeutics increases every year. This Account presents the development of an AD treatment strategy that incorporates diverse compounds with a common characteristic: the ability to redistribute metal ions within the brain. Central to cognitive decline in AD is the amyloid-β peptide (Aβ) that accumulates in the AD brain. A range of therapeutic strategies have been developed based on the premise that decreasing the brain Aβ burden will attenuate the severity of the disease symptoms. Unfortunately these treatments have failed to show any positive outcomes in large-scale clinical trials, raising many questions regarding whether therapeutics for AD can rely solely on decreasing Aβ levels. An alternate strategy is to target the interaction between Aβ and metal ions using compounds with the potential to redistribute metal ions within the brain. The original rationale for this strategy came from studies showing that metal ions promote Aβ toxicity and aggregation. In initial studies using the prototype metal-chelating compound clioquinol (CQ), CQ prevented Aβ toxicity in vitro, out-competed Aβ for metal ions without affecting the activity of metal-dependent enzymes, and attenuated the rate of cognitive decline in AD subjects in a small phase II clinical trial. All these outcomes were consistent with the original hypothesized mechanism of action for CQ where prevention or reversal of the extracellular Aβ-metal interactions could prevent Aβ toxicity. Soon after the completion of these studies, a new body of work began to suggest that this hypothesized mechanism of action for CQ was simplistic and that other factors were also important for the positive therapeutic outcomes. Perhaps most significantly, it was shown that after CQ sequesters metal ions the neutral CQ-metal

  13. Auger neutralization rates of multiply charged ions near metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Nedeljkovic, N.N.; Janev, R.K.; Lazur, V.Y.

    1988-08-15

    Transition rates for the Auger neutralization processes of multiply charged ions on metal surfaces are calculated in closed analytical form. The core potential of a multiply charged ion is represented by a pseudopotential, which accounts for the electron screening effects and allows transition to the pure Coulomb case (fully stripped ions). The relative importance of various neutralization channels in slow-ion--surface collisions is discussed for the examples of He/sup 2+/+Mo(100) and C/sup 3+/+Mo(100) collisional systems.

  14. Inhibition of hot salt corrosion by metallic additives

    Science.gov (United States)

    Deadmore, D. L.; Lowell, C. E.

    1978-01-01

    The effectiveness of several potential fuel additives in reducing the effects of sodium sulfate-induced hot corrosion was evaluated in a cyclic Mach 0.3 burner rig. The potential inhibitors examined were salts of Al, Si, Cr, Fe, Zn, Mg, Ca, and Ba. The alloys tested were IN-100, U-700, IN-738, IN-792, Mar M-509, and 304 stainless steel. Each alloy was exposed for 100 cycles of 1 hour each at 900 C in combustion gases doped with the corrodant and inhibitor salts and the extent of attack was determined by measuring maximum metal thickness loss. The most effective and consistent inhibitor additive was Ba (NO3)2 which reduced the hot corrosion attack to nearly that of simple oxidation.

  15. Metal ion interpretation in resurfacing versus conventional hip arthroplasty and in whole blood versus serum. How should we interpret metal ion data

    NARCIS (Netherlands)

    Smolders, J.M.; Bisseling, P.; Hol, A.; Straeten, C. Van Der; Schreurs, B.W.; Susante, J.L.C. van

    2011-01-01

    Metal ions generated from joint replacements are a cause for concern. There is no consensus on the best surrogate measure of metal ion exposure, and both serum and whole blood measurements are used in clinical practice. This study provides a guideline for interpretation of metal ion analysis in clin

  16. Metal ion interpretation in resurfacing versus conventional hip arthroplasty and in whole blood versus serum. How should we interpret metal ion data

    NARCIS (Netherlands)

    Smolders, J.M.; Bisseling, P.; Hol, A.; Straeten, C. Van Der; Schreurs, B.W.; Susante, J.L.C. van

    2011-01-01

    Metal ions generated from joint replacements are a cause for concern. There is no consensus on the best surrogate measure of metal ion exposure, and both serum and whole blood measurements are used in clinical practice. This study provides a guideline for interpretation of metal ion analysis in clin

  17. 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.

  18. Chromosomal antioxidant genes have metal ion-specific roles as determinants of bacterial metal tolerance.

    Science.gov (United States)

    Harrison, Joe J; Tremaroli, Valentina; Stan, Michelle A; Chan, Catherine S; Vacchi-Suzzi, Caterina; Heyne, Belinda J; Parsek, Matthew R; Ceri, Howard; Turner, Raymond J

    2009-10-01

    Microbiological metal toxicity involves redox reactions between metal species and cellular molecules, and therefore, we hypothesized that antioxidant systems might be chromosomal determinants affecting the susceptibility of bacteria to metal toxicity. Here, survival was quantified in metal ion-exposed planktonic cultures of several Escherichia coli strains, each bearing a mutation in a gene important for redox homeostasis. This characterized approximately 250 gene-metal combinations and identified that sodA, sodB, gor, trxA, gshA, grxA and marR have distinct roles in safeguarding or sensitizing cells to different toxic metal ions (Cr(2)O(7)(2-), Co(2+), Cu(2+), Ag(+), Zn(2+), AsO(2)(-), SeO(3)(2-) or TeO(3)(2-)). To shed light on these observations, fluorescent sensors for reactive oxygen species (ROS) and reduced thiol (RSH) quantification were used to ascertain that different metal ions exert oxidative toxicity through disparate modes-of-action. These oxidative mechanisms of metal toxicity were categorized as involving ROS and thiol-disulfide chemistry together (AsO(2)(-), SeO(3)(2-)), ROS predominantly (Cu(2+), Cr(2)O(7)(2-)) or thiol-disulfide chemistry predominantly (Ag(+), Co(2+), Zn(2+), TeO(3)(2-)). Corresponding to this, promoter-luxCDABE fusions showed that toxic doses of different metal ions up- or downregulate the transcription of gene sets marking distinct pathways of cellular oxidative stress. Altogether, our findings suggest that different metal ions are lethal to cells through discrete pathways of oxidative biochemistry, and moreover, indicate that chromosomally encoded antioxidant systems may have metal ion-specific physiological roles as determinants of bacterial metal tolerance.

  19. Ion conducting fluoropolymer carbonates for alkali metal ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Balsara, Nitash P.; Thelen, Jacob; Devaux, Didier

    2017-09-05

    Liquid or solid electrolyte compositions are described that comprise a homogeneous solvent system and an alkali metal salt dissolved in said solvent system. The solvent system may comprise a fluoropolymer, having one or two terminal carbonate groups covalently coupled thereto. Batteries containing such electrolyte compositions are also described.

  20. Rat liver mitochondrial dysfunction by addition of copper(II) or iron(III) ions.

    Science.gov (United States)

    Saporito-Magriñá, Christian; Musacco-Sebio, Rosario; Acosta, Juan M; Bajicoff, Sofía; Paredes-Fleitas, Paola; Boveris, Alberto; Repetto, Marisa G

    2017-01-01

    Increased copper (Cu) and iron (Fe) levels in liver and brain are associated to oxidative stress and damage with increased phospholipid oxidation process. The aim of this work was to assess the toxic effects of Cu(2+) and Fe(3+) addition to rat liver mitochondria by determining mitochondrial respiration in states 3 (active respiration) and 4 (resting respiration), and phospholipid peroxidation. Both, Cu(2+) and Fe(3+) produced decreases in O2 consumption in a concentration-dependent manner in active state 3: both ions by 42% with malate-glutamate as complex I substrate (concentration for half maximal response (C50) 60μM Cu(2+) and 1.25mM Fe(3+)), and with succinate as complex II substrate: 64-69% with C50 of 50μM Cu(2+) and with C50 of 1.25mM of Fe(3+). Respiratory control decreased with Cu(2+) (C50 50μM) and Fe(3+) (C50 1.25-1-75mM) with both substrates. Cu(2+) produced a 2-fold increase and Fe(3+) a 5-fold increase of thiobarbituric acid-reactive substances (TBARS) content from 25μM Cu(2+) (C50 40μM) and from 100μM Fe(3+) (C50 1.75mM). Supplementations with Cu(2+) and Fe(3+) ions induce mitochondrial dysfunction with phospholipid peroxidation in rat liver mitochondria. Although is proved that a Fenton/Haber Weiss mechanism of oxidative damage occurs in metal-ion induced mitochondrial toxicity, slightly different responses to the metal ions suggest some differences in the mechanism of intracellular toxicity. The decreased rates of mitochondrial respiration and the alteration of mitochondrial function by phospholipid and protein oxidations lead to mitochondrial dysfunction, cellular dyshomeostasis and cell death.

  1. Characterization of duplex hard coatings with additional ion implantation

    Directory of Open Access Journals (Sweden)

    B. Škorić

    2012-01-01

    Full Text Available In this paper, we present the results of a study of TiN thin fi lms which are deposited by a Physical Vapour Deposition (PVD and Ion Beam Assisted Deposition (IBAD. In the present investigation the subsequent ion implantation was provided with N+2 ions. The ion implantation was applied to enhance the mechanical properties of surface. The thin film deposition process exerts a number of eff ects such as crystallographic orientation, morphology, topography, densifi cation of the fi lms. The evolution of the microstructure from porous and columnar grains to densel packed grains is accompanied by changes in mechanical and physical properties. A variety of analytic techniques were used for characterization, such as scratch test, calo test, Scanning electron microscopy (SEM, Atomic Force Microscope (AFM, X-ray diff raction (XRD and Energy Dispersive X-ray analysis (EDAX.

  2. A new strategy to stabilize oxytocin in aqueous solutions: I. The effects of divalent metal ions and citrate buffer.

    Science.gov (United States)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J M; Hinrichs, Wouter L J; Frijlink, Henderik W

    2011-06-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na(+) and K(+)) and divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of aqueous oxytocin solutions was determined by RP-HPLC and HP-SEC after 4 weeks of storage at either 4°C or 55°C. Addition of sodium or potassium ions to acetate- or citrate-buffered solutions did not increase stability, nor did the addition of divalent metal ions to acetate buffer. However, the stability of aqueous oxytocin in aqueous formulations was improved in the presence of 5 and 10 mM citrate buffer in combination with at least 2 mM CaCl(2), MgCl(2), or ZnCl(2) and depended on the divalent metal ion concentration. Isothermal titration calorimetric measurements were predictive for the stabilization effects observed during the stability study. Formulations in citrate buffer that had an improved stability displayed a strong interaction between oxytocin and Ca(2+), Mg(2+), or Zn(2+), while formulations in acetate buffer did not. In conclusion, our study shows that divalent metal ions in combination with citrate buffer strongly improved the stability of oxytocin in aqueous solutions.

  3. Interactions Between Metal Ions and Carbohydrates: Coordination Behavior of D-Ribose to Lanthanide Ions

    Institute of Scientific and Technical Information of China (English)

    苏允兰; 杨丽敏; 翁诗甫; 吴瑾光

    2002-01-01

    Lanthanum chloride α-D-ribopyranose pentahydrate complex was prepared and speculated its structure from the similar IR spectra of corresponding praseodymium and neodymium-D-ribose complexes, which reveal the coordination behavior of D-ribose to lanthanide ions and give us a model of the interactions between metal ions and carbohydrates.

  4. Ab Initio Molecular Dynamics Study on the Interactions between Carboxylate Ions and Metal Ions in Water.

    Science.gov (United States)

    Mehandzhiyski, Aleksandar Y; Riccardi, Enrico; van Erp, Titus S; Trinh, Thuat T; Grimes, Brian A

    2015-08-20

    The interaction between a carboxylate anion (deprotonated propanoic acid) and the divalent Mg(2+), Ca(2+), Sr(2+), Ba(2+) metal ions is studied via ab initio molecular dynamics. The main focus of the study is the selectivity of the carboxylate-metal ion interaction in aqueous solution. The interaction is modeled by explicitly accounting for the solvent molecules on a DFT level. The hydration energies of the metal ions along with their diffusion and mobility coefficients are determined and a trend correlated with their ionic radius is found. Subsequently, a series of 16 constrained molecular dynamics simulations for every ion is performed, and the interaction free energy is obtained from thermodynamic integration of the forces between the metal ion and the carboxylate ion. The results indicate that the magnesium ion interacts most strongly with the carboxylate, followed by calcium, strontium, and barium. Because the interaction free energy is not enough to explain the selectivity of the reaction observed experimentally, more detailed analysis is performed on the simulation trajectories to understand the steric changes in the reaction complex during dissociation. The solvent dynamics appear to play an important role during the dissociation of the complex and also in the observed selectivity behavior of the divalent ions.

  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. Reducing hazardous heavy metal ions using mangium bark waste.

    Science.gov (United States)

    Khabibi, Jauhar; Syafii, Wasrin; Sari, Rita Kartika

    2016-08-01

    The objective of this study was to evaluate the characteristics of mangium bark and its biosorbent ability to reduce heavy metal ions in standard solutions and wastewater and to assess changes in bark characteristics after heavy metal absorption. The experiments were conducted to determine heavy metal absorption from solutions of heavy metals alone and in mixtures as well as from wastewater. The results show that mangium bark can absorb heavy metals. Absorption percentages and capacities from single heavy metal solutions showed that Cu(2+) > Ni(2+) > Pb(2+) > Hg(2+), while those from mixture solutions showed that Hg(2+) > Cu(2+) > Pb(2+) > Ni(2+). Wastewater from gold mining only contained Cu, with an absorption percentage and capacity of 42.87 % and 0.75 mg/g, respectively. The highest absorption percentage and capacity of 92.77 % and 5.18 mg/g, respectively, were found for Hg(2+) in a mixture solution and Cu(2+) in single-metal solution. The Cu(2+) absorption process in a single-metal solution changed the biosorbent characteristics of the mangium bark, yielding a decreased crystalline fraction; changed transmittance on hydroxyl, carboxyl, and carbonyl groups; and increased the presence of Cu. In conclusion, mangium bark biosorbent can reduce hazardous heavy metal ions in both standard solutions and wastewater.

  7. Sensitive Determination of DNA by RLS Enhancement of Metal Ions

    Institute of Scientific and Technical Information of China (English)

    Huang Jian-ping; Chen Fang; Ai Xin-ping; He Zhi-ke

    2004-01-01

    The interactions between metal ions and DNA have been studied by the resonance light scattering (RLS) spectra. In the acidic condition, the RLS signals of metal ions, especially the transition metal ions in group ⅠB and ⅡB, were increased by DNA. And it is found that the enhancement of RLS signals is linear to the concentration of DNA, so the RLS method for DNA determination was proposed in the presence of Cu2+. On the optimum conditions, the linear range and the detect limit of ctDNA is 4×10-8-4×10-6 g·5mL-1 and 1.13×10-8 g·5mL-1, respectively. The proposed method is successfully applied to determine the extracted plasmid DNA of Bacillus subtilis DB104.

  8. The effect of metal ions on the photophysical and photochemical property of phenylthio bromo metal phthalocyanines

    Science.gov (United States)

    Pan, Sujuan; Shen, Pingping; Ma, Dongdong; Wang, Yuhua; Zhang, Tiantian; Chen, Kuizhi; Yang, Hongqin; Xie, Shusen; Peng, Yiru

    2016-10-01

    Phthalocyanines have attracted great attention because of their applications in material science including electro-optical devices, electrochromic display, and photodynamic therapy (PDT) of cancer. In addition, the Pcs exhibit great flexibility of chemical structure modification enabled by either peripheral substituents or metal ions co-ordination to central cavity of highly conjugated tetrapyrrolic macrocycles. However, because of the hydrophobic nature of the phthalocyanine ring, Pcs have strong tendency to aggregate in solution, which limited their applications. To overcome this problem, the introduction of dendritic wedge to peripheral positions of phthalocyanines can prevent the formation of aggregation to some extent. The preparation procedure involved the modification of the zinc (II) and magnesium (II) phthalocyanines with peripherally dendritic substitutions. The photophysical and photochemical properties of dendritic phthalocyanines were studied by UV/Vis and fluorescence spectroscopic methods. Compared with the magnesium (II) phthalocyanine, the intensity of Q band of zinc (II) phthalocyanine was increased but no obviously position changes was observed. Furthermore, the zinc (II) phthalocyanine exhibited relatively higher fluorescence intensity than the magnesium (II) phthalocyanine. The fluorescence quantum yield and lifetimes of magnesium (II) phthalocyanine was clearly longer than that of zinc (II) phthalocyanine. As the better photosensitizer, the zinc (II) phthalocyanine has higher singlet oxygen quantum yield owning superior performance. This results indicated that the singlet oxygen quantum yield would be effected by the nature of metal ions.

  9. Metal Big Area Additive Manufacturing: Process Modeling and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, Srdjan [ORNL; Nycz, Andrzej [ORNL; Noakes, Mark W [ORNL; Chin, Charlie [Dassault Systemes; Oancea, Victor [Dassault Systemes

    2017-01-01

    Metal Big Area Additive Manufacturing (mBAAM) is a new additive manufacturing (AM) technology for printing large-scale 3D objects. mBAAM is based on the gas metal arc welding process and uses a continuous feed of welding wire to manufacture an object. An electric arc forms between the wire and the substrate, which melts the wire and deposits a bead of molten metal along the predetermined path. In general, the welding process parameters and local conditions determine the shape of the deposited bead. The sequence of the bead deposition and the corresponding thermal history of the manufactured object determine the long range effects, such as thermal-induced distortions and residual stresses. Therefore, the resulting performance or final properties of the manufactured object are dependent on its geometry and the deposition path, in addition to depending on the basic welding process parameters. Physical testing is critical for gaining the necessary knowledge for quality prints, but traversing the process parameter space in order to develop an optimized build strategy for each new design is impractical by pure experimental means. Computational modeling and optimization may accelerate development of a build process strategy and saves time and resources. Because computational modeling provides these opportunities, we have developed a physics-based Finite Element Method (FEM) simulation framework and numerical models to support the mBAAM process s development and design. In this paper, we performed a sequentially coupled heat transfer and stress analysis for predicting the final deformation of a small rectangular structure printed using the mild steel welding wire. Using the new simulation technologies, material was progressively added into the FEM simulation as the arc weld traversed the build path. In the sequentially coupled heat transfer and stress analysis, the heat transfer was performed to calculate the temperature evolution, which was used in a stress analysis to

  10. Determination of Some Heavy-metal-ions Using a Sulfur Ion Modified BZ Oscillating System

    Institute of Scientific and Technical Information of China (English)

    Hua CHEN; Wu YANG; Hong Xia DAI; Xiao Xia WEI; Jie QU; Jin Zhang GAO

    2006-01-01

    A highly sensitive method is developed for the determination of trace amounts of some heavy metal ions in aqueous solution based on the classical Belousov-Zhabotinskii (BZ) oscillating chemical system. Introducing of S2- ion makes the new oscillating system Ce(SO4)2 - KBrO3-CH2(COOH)2 - Na2S - H2SO4 have to a high sensitivity for some heavy metal ions such as Ag+,pb2+, Hg2+, Cd2+, Cu2+and Bi3+ with detection limits down to 10-12 mol. L-1.

  11. Binding of alkali metal ions by cyclic polyethers: significance in ion transport processes.

    Science.gov (United States)

    Izatt, R M; Rytting, J H; Nelson, D P; Haymore, B L; Christensen, J J

    1969-04-25

    Values for the formation constant (log K), the change in enthalpy (triangle upH degrees ), and the change in entropy (triangle upS degrees ) have been determined for the interaction of lithium, sodium, potassium, rubidium, and cesium ions with the two isomers of the cyclic polyether, 2,5,8,15,18,21-hexaoxatricyclo[20.4.0.0(9,14)] hexacosane. The stability order of these metal ions with either isomer is identical to the permeability order for these same metal ions with the structurally related antibiotics, valinomycin and monactin.

  12. Application of atomic and molecular primary ions for TOF SIMS analysis of additive containing polymer surfaces

    Science.gov (United States)

    Stapel, D.; Benninghoven, A.

    2001-04-01

    The influence of primary ion mass and composition on secondary ion emission of the additive Irganox 1010 ( m=1176 u) in polyethylene was investigated. O +, Ar +, Xe +, O 2+, CO 2+, SF 5+, C 7H 7+, C 10H 8+, C 6F 6+, and C 10F 8+ with a total energy of 11 keV were used as primary ions under static secondary ion mass spectrometry (SIMS) conditions. Positive and negative molecular secondary ions characterizing the additive were determined and their yields were evaluated. For all characteristic secondary ions we found a strong yield enhancement with increasing mass for atomic primary ions and increasing number of constituents for molecular primary ions. This yield enhancement is saturated once the molecular primary ion is made of more than six heavy atoms. In addition this yield increase depends on the mass and structure of the considered secondary ion. We did not find any evidence for an influence of the chemical composition of the applied molecular primary ions on the secondary ion emission when static SIMS conditions were met. The improved imaging capabilities of molecular primary ions was demonstrated by comparing focused Ar + and SF 5+ primary ion beams when mapping characteristic secondary ion emission from a structured additive containing polypropylene surface.

  13. Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted $^{163}$Ho ions

    CERN Document Server

    Gastaldo, L; von Seggern, F; Porst, J P; Schäfer, S; Pies, C; Kempf, S; Wolf, T; Fleischmann, A; Enss, C; Herlert, A; Johnston, K

    2013-01-01

    For the first time we have investigated the behavior of fully micro-fabricated low temperature metallic magnetic calorimeters (MMCs) after undergoing an ion-implantation process. This experiment had the aim to show the possibility to perform a high precision calorimetric measurement of the energy spectrum following the electron capture of $^{163}$Ho using MMCs having the radioactive $^{163}$Ho ions implanted in the absorber. The implantation of $^{163}$Ho ions was performed at ISOLDE-CERN. The performance of a detector that underwent an ion-implantation process is compared to the one of a detector without implanted ions. The results show that the implantation dose of ions used in this experiment does not compromise the properties of the detector. In addition an optimized detector design for future $^{163}$Ho experiments is presented.

  14. Metal Ions Extraction with Glucose Derivatives as Chelating Reagents in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Guo Chen YANG; Hai Jian YANG

    2006-01-01

    A series of glucose derivatives have been used as chelating reagents to extract metal ions in supercritical carbon dioxide. With perfluoro-1-octanesulfonic acid tetraethylammonium salt as additive, glucose derivatives were selective for Sr2+ and Pb2+ extraction in supercritical carbon dioxide.

  15. Metal ion coordination, conditional stability constants, and solution behavior of chelating surfactant metal complexes.

    Science.gov (United States)

    Svanedal, Ida; Boija, Susanne; Almesåker, Ann; Persson, Gerd; Andersson, Fredrik; Hedenström, Erik; Bylund, Dan; Norgren, Magnus; Edlund, Håkan

    2014-04-29

    Coordination complexes of some divalent metal ions with the DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) have been examined in terms of chelation and solution behavior. The headgroup of 4-C12-DTPA contains eight donor atoms that can participate in the coordination of a metal ion. Conditional stability constants for five transition metal complexes with 4-C12-DTPA were determined by competition measurements between 4-C12-DTPA and DTPA, using electrospray ionization mass spectrometry (ESI-MS). Small differences in the relative strength between the coordination complexes of DTPA and 4-C12-DTPA indicated that the hydrocarbon tail only affected the chelating ability of the headgroup to a limited extent. The coordination of Cu(2+) ions was investigated in particular, using UV-visible spectroscopy. By constructing Job's plots, it was found that 4-C12-DTPA could coordinate up to two Cu(2+) ions. Surface tension measurements and NMR diffusometry showed that the coordination of metal ions affected the solution behavior of 4-C12-DTPA, but there were no specific trends between the studied divalent metal complexes. Generally, the effects of the metal ion coordination could be linked to the neutralization of the headgroup charge of 4-C12-DTPA, and the resulting reduced electrostatic repulsions between adjacent surfactants in micelles and monolayers. The pH vs concentration plots, on the other hand, showed a distinct difference between 4-C12-DTPA complexes of the alkaline earth metals and the transition metals. This was explained by the difference in coordination between the two groups of metal ions, as predicted by the hard and soft acid and base (HSAB) theory.

  16. De novo design of peptide scaffolds as novel preorganized ligands for metal-ion coordination.

    Science.gov (United States)

    Gamble, Aimee J; Peacock, Anna F A

    2014-01-01

    This chapter describes how de novo designed peptides can be used as novel preorganized ligands for metal ion coordination. The focus is on the design of peptides which are programmed to spontaneously self-assemble into α-helical coiled coils in aqueous solution, and how metal ion binding sites can be engineered onto and into these structures. In addition to describing the various design principles, some key examples are covered illustrating the success of this approach, including a more detailed example in the case study.

  17. Nano sized carbonized waste biomass for heavy metal ion remediation

    Directory of Open Access Journals (Sweden)

    Mahajan Garima

    2014-12-01

    Full Text Available Utilization of agricultural waste material with approach to enhance the heavy metal remediation properties by carbonizing the biomass at nano size particles has been explored in present investigation from aqueous solutions. In this study the lignocellulosic, nitrogenous agricultural waste biomass Delbergia sissoo pods (DSP has been tried for sequestering of Cd (II, Pb (II and Ni (II metal ions from aqueous solutions. Batch experiments were performed for removal of targeted metal ions keeping in consideration the preliminary affecting parameters such as effect of adsorption dose, pH, initial metal ion concentration, stirring speed and contact time. The sorption studies were analyzed by using, Freundlic isotherm and Langmuir isotherm models. The kinetics of the process was evaluated by pseudo pseudo-first order and pseudo second order kinetic models. Studies reveal that the equilibrium was achieved with in 30 min of the contact time at optimized parameters. Analytical studies of biosorbent were done by means of FT-IR, SEM and XRD. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

  18. 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

    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-melanocortin stimulat......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...... of the metal ion appeared to be additive, because the maximal cAMP response for alpha-MSH in the presence of Zn(II) was 60% above the maximal response for the peptide alone. The affinity of Zn(II) could be increased through binding of the metal ion in complex with small hydrophobic chelators. The binding...... 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...

  19. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fish, D. [Lawrence Berkeley National Lab., CA (United States)

    1996-10-01

    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.

  1. Metal ions and RNA folding: a highly charged topic with a dynamic future.

    Science.gov (United States)

    Woodson, Sarah A

    2005-04-01

    Metal ions are required to stabilize RNA tertiary structure and to begin the folding process. How different metal ions enable RNAs to fold depends on the electrostatic potential of the RNA and correlated fluctuations in the positions of the ions themselves. Theoretical models, fluorescence spectroscopy, small angle scattering and structural biology reveal that metal ions alter the RNA dynamics and folding transition states. Specifically coordinated divalent metal ions mediate conformational rearrangements within ribozyme active sites.

  2. Process for improving moisture resistance of epoxy resins by addition of chromium ions

    Science.gov (United States)

    St.clair, A. K.; Stoakley, D. M.; St.clair, T. L.; Singh, J. J. (Inventor)

    1985-01-01

    A process for improving the moisture resistance properties of epoxidized TGMDA and DGEBA resin system by chemically incorporating chromium ions is described. The addition of chromium ions is believed to prevent the absorption of water molecules.

  3. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils

    Energy Technology Data Exchange (ETDEWEB)

    Li Yongtao [College of Natural Resources and Environment, South China Agricultural University, 510642 Guangzhou (China); Laboratoire de Geochimie des Eaux, Universite Paris-Diderot - IPGP, Case 7052, Batiment Lamarck, 75205 Paris Cedex 13 (France); Becquer, Thierry [UMR 137 Biodiversite et Fonctionnement des Sols, IRD/Universites Paris VI and XII, SupAgro - Bat. 12, 2 Place Viala, 34060 Montpellier Cedex 2 (France); Dai Jun [College of Natural Resources and Environment, South China Agricultural University, 510642 Guangzhou (China); Quantin, Cecile [UMR 8148 IDES, Universite Paris Sud XI - CNRS, Bat. 504, 91405 Orsay Cedex (France); Benedetti, Marc F. [Laboratoire de Geochimie des Eaux, Universite Paris-Diderot - IPGP, Case 7052, Batiment Lamarck, 75205 Paris Cedex 13 (France)], E-mail: benedetti@ipgp.fr

    2009-04-15

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils. - First evidence of the real free metal ion concentrations in acid mine drainage context in tropical systems.

  4. Roxarsone desorption from the surface of goethite by competitive anions, phosphate and hydroxide ions: Significance of the presence of metal ions.

    Science.gov (United States)

    Wang, Ling-Yuan; Wang, Shao-Wei; Chen, Wan-Ru

    2016-06-01

    Aromatic organoarsenical roxarsone (ROX) is a common additive for livestock feed. This arsenic containing pollutant could be discharged into the environment through agricultural application of animal manure, and pose potential threats to both humans and the wider environment. In this study, the influence of pH, competing anions and metal ions on the adsorption and desorption of ROX on goethite were investigated in order to understand their mobility in the environment. Both hydroxide ions and phosphate are common substances in the environment, and both are potential competing anions for ROX. Our results showed the addition of phosphate desorbed more ROX than the addition of hydroxide ions. As pH increased, the effect of phosphate did not show much difference to that of hydroxide ion. The results indicate that the presence of phosphate will greatly increase the mobility of ROX at low pH. Six common metal ions, including Zn(2+), Cu(2+), Fe(3+), Mn(2+), Mg(2+), and Ca(2+), were tested and all spiked metal ions enhanced the stability of ROX adsorption on the surface of goethite, and led to less desorption when phosphate was added. The results demonstrate that metal ions may form complex/surface precipitation with ROX to enhance its adsorption. The effect from Fe(3+), Zn(2+) and Cu(2+) was more pronounced than other metal ions, which might result from the fact that these three metal ions tend to associate with hydroxide ions and decrease the pH. The results of this research may shed light on the environmental fate and transportation of aromatic organoarsenicals in soil.

  5. Interatomic interaction of additive elements and their influence on the processes in the double metal solutions

    Directory of Open Access Journals (Sweden)

    Марина Анатоліівна Рябікіна

    2016-07-01

    Full Text Available Modern industry uses a lot of elements as additives to improve the service characteristics of metal products that are to be used for various purposes. These elements can be divided into two groups: the first group includes the elements interacting with iron and improving its characteristics (alloying elements, and the second group includes the elements, that modify the characteristics of the structure and properties in an undesirable direction. These are trace elements: S, P, O, As, and others in steel. The negative impact of these elements shows itself as banding, the formation of non-metallic inclusions, flakes, grain boundary segregations et al. The influence of the elements of the both groups on the properties of steel depends on the nature and level of interatomic interaction in the alloy. Computational and analytical study of the major impurity elements in steel impact on the interatomic bond strength and the probability of forming complexes, clusters, and chemical compounds with the basic alloying elements in the steel has been carried out in the work. The theoretical parameter which defines the strength of the ion-covalent bond of two atoms: non-metallicmetallic is the electronegativity of elements. The electronegativity difference of the metal and non-metallic elements increasing, the ionic bonding and thermodynamic stability of these compounds  increase. On the other hand, concentration of valent electrons is a universal characteristic of an atomic element which determines many of its properties, and especially the energy of interatomic interaction. Energy calculations of pairwise interatomic impurity elements: H, C, N, S, P, As interaction with Fe and major alloying elements in steel: Mn, Cr, Si, V, Al, Ti, W, Cu, Mo, Nb were made. It has been stated that all the impurity elements except phosphorus, hydrogen and arsenic have sufficient high adhesion with the majority of the metal elements in the modern steels. Phosphorus does

  6. Determination of metal ion content of beverages and estimation of target hazard quotients: a comparative study

    Directory of Open Access Journals (Sweden)

    Barker James

    2008-06-01

    Full Text Available Abstract Background Considerable research has been directed towards the roles of metal ions in nutrition with metal ion toxicity attracting particular attention. The aim of this study is to measure the levels of metal ions found in selected beverages (red wine, stout and apple juice and to determine their potential detrimental effects via calculation of the Target Hazard Quotients (THQ for 250 mL daily consumption. Results The levels (mean ± SEM and diversity of metals determined by ICP-MS were highest for red wine samples (30 metals totalling 5620.54 ± 123.86 ppb followed by apple juice (15 metals totalling 1339.87 ± 10.84 ppb and stout (14 metals totalling 464.85 ± 46.74 ppb. The combined THQ values were determined based upon levels of V, Cr, Mn, Ni, Cu, Zn and Pb which gave red wine samples the highest value (5100.96 ± 118.93 ppb followed by apple juice (666.44 ± 7.67 ppb and stout (328.41 ± 42.36 ppb. The THQ values were as follows: apple juice (male 3.11, female 3.87, stout (male 1.84, female 2.19, red wine (male 126.52, female 157.22 and ultra-filtered red wine (male 110.48, female 137.29. Conclusion This study reports relatively high levels of metal ions in red wine, which give a very high THQ value suggesting potential hazardous exposure over a lifetime for those who consume at least 250 mL daily. In addition to the known hazardous metals (e.g. Pb, many metals (e.g. Rb have not had their biological effects systematically investigated and hence the impact of sustained ingestion is not known.

  7. Formation of Metal-Related Ions in Matrix-Assisted Laser Desorption Ionization

    Science.gov (United States)

    Lee, Chuping; Lu, I.-Chung; Hsu, Hsu Chen; Lin, Hou-Yu; Liang, Sheng-Ping; Lee, Yuan-Tseh; Ni, Chi-Kung

    2016-09-01

    In a study of the metal-related ion generation mechanism in matrix-assisted laser desorption ionization (MALDI), crystals of matrix used in MALDI were grown from matrix- and salt-containing solutions. The intensities of metal ion and metal adducts of the matrix ion obtained from unwashed crystals were higher than those from crystals washed with deionized water, indicating that metal ions and metal adducts of the matrix ions are mainly generated from the surface of crystals. The contributions of preformed metal ions and metal adducts of the matrix ions inside the matrix crystals were minor. Metal adducts of the matrix and analyte ion intensities generated from a mixture of dried matrix, salt, and analyte powders were similar to or higher than those generated from the powder of dried droplet crystals, indicating that the contributions of the preformed metal adducts of the matrix and analyte ions were insignificant. Correlation between metal-related ion intensity fluctuation and protonated ion intensity fluctuation was observed, indicating that the generation mechanism of the metal-related ions is similar to that of the protonated ions. Because the thermally induced proton transfer model effectively describes the generation of the protonated ions, we suggest that metal-related ions are mainly generated from the salt dissolution in the matrix melted by the laser.

  8. Metal ion release from electric guitar strings in artificial sweat

    Energy Technology Data Exchange (ETDEWEB)

    Rezic, Iva [Department of Applied Chemistry, Faculty of Textile Technology, University of Zagreb, Prilaz Baruna Filipovica 28a, 10000 Zagreb (Croatia)], E-mail: iva_rezic@net.hr; Curkovic, Lidija [Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb (Croatia); Ujevic, Magdalena [Croatian Institute of Public Health, Zagreb, Croatia (Croatia)

    2009-09-15

    The aim of this study was to monitor the dissolution of metal ions from electric guitar strings. For characterization of investigated strings, two independent methods of analysis were chosen: ICP-OES and AAS. Electric guitar strings consisted of two separate parts: Sn-plated steel core wire which was hexagonal in cross section and Ni-plated steel wrap which was round in cross section. Dissolution of Ni{sup 2+}, Mn{sup 2+}, Si{sup 4+}, Sn{sup 2+} and Fe{sup 3+} ions from electric guitar strings E6 and D4 were measured as a function of time in artificial sweat solution, at temperature of 37 deg. C according to the EN 1811:1999 standard test procedure. The determination of the amount of the metal ions released in the corrosive solutions was carried out by means of inductively coupled plasma-optical emission spectroscopy (ICP-OES). The mechanism of metal ions eluted in artificial sweat is discussed. The concentrations of dissolved metal ions in corrosive solution from E6 and D4 strings are decreasing in the following order: Fe{sup 3+} > Sn{sup 2+} > Mn{sup 2+} > Si{sup 4+} > Ni{sup 2+}. Among all investigated metal ions, nickel is far the most allergenic. Since the amounts of the eluted Ni{sup 2+} did not exceed 0.5 {mu}g cm{sup -2} week{sup -1}, the investigated electric guitar strings should not induce contact dermatitis.

  9. Novel kinetic model of the removal of divalent heavy metal ions from aqueous solutions by natural clinoptilolite.

    Science.gov (United States)

    Jovanovic, Mina; Rajic, Nevenka; Obradovic, Bojana

    2012-09-30

    Removal of heavy metal ions from aqueous solutions using zeolites is widely described by pseudo-second order kinetics although this model may not be valid under all conditions. In this work, we have extended approaches used for derivation of this model in order to develop a novel kinetic model that is related to the ion exchange mechanism underlying sorption of metal ions in zeolites. The novel model assumed two reversible steps, i.e. release of sodium ions from the zeolite lattice followed by bonding of the metal ion. The model was applied to experimental results of Cu(II) sorption by natural clinoptilolite-rich zeolitic tuff at different initial concentrations and temperatures and then validated by predictions of ion exchange kinetics of other divalent heavy metal ions (i.e. Mn(II), Zn(II) and Pb(II)). Model predictions were in excellent agreements with experimental data for all investigated systems. In regard to the proposed mechanism, modeling results implied that the sodium ion release rate was constant for all investigated metals while the overall rate was mainly determined by the rate of heavy metal ion bonding to the lattice. In addition, prediction capabilities of the novel model were demonstrated requiring one experimentally determined parameter, only.

  10. Characterization of charge and kinetic energy distribution of ions emitted during nanosecond pulsed laser ablation of several metals

    Science.gov (United States)

    Dogar, A. H.; Ullah, S.; Qayyum, H.; Rehman, Z. U.; Qayyum, A.

    2017-09-01

    The ion flux from various metals (Al, Ti, Cu, Sn and W) ablated with 20 ns Nd:YAG laser radiation at a wavelength of 1064 nm was investigated by an ion collector operating in time-of-flight (TOF) configuration. The laser irradiance at the target was varied in the range of 1.7  ×  108–5.73  ×  108 W cm‑2. Ion yield from various metals showed a linearly increasing trend with increasing laser irradiance, whereas ion yield was found to decrease with an increasing atomic mass of the target. Our results clearly indicate that ion yield is not a function of the volatility of the metal. TOF ion spectra showed at least two groups of low intensity peaks due to fast ions. The first group of ion peaks, which was present in the spectra of all five metals, was due to surface contamination. The additional fast ion structures in the spectra of Sn and W can be related to the ion acceleration due to the prompt electron emission from these high-Z metals. The ion velocity follows the anticipated inverse square root dependence on the ion mass. For the range of laser irradiance investigated here, the most probable energy of the Cu ions increases from about 100–600 eV. The fast increase in ion energy above ~3  ×  108 W cm‑2 is related to the increase of the Columb part of the ion energy due to the production of multiply charged ions.

  11. Selective fluorescence sensors for detection of nitroaniline and metal Ions based on ligand-based luminescent metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zongchao [College of Environment and Chemical Engineering & Key Lab of Hollow Fiber Membrane Materials & Membrane Process, Tianjin Polytechnic University, Tianjin 300387 (China); Wang, Fengqin, E-mail: wangfengqin@tjpu.edu.cn [College of Environment and Chemical Engineering & Key Lab of Hollow Fiber Membrane Materials & Membrane Process, Tianjin Polytechnic University, Tianjin 300387 (China); Lin, Xiangyi [Suzhou Huihe Pharmaceutical Limited Company, Suzhou 215200 (China); Wang, Chengmiao; Fu, Yiyuan; Wang, Xiaojun [College of Environment and Chemical Engineering & Key Lab of Hollow Fiber Membrane Materials & Membrane Process, Tianjin Polytechnic University, Tianjin 300387 (China); Zhao, Yongnan [College of Materials and Engineering & Key Lab of Hollow Fiber Membrane Materials & Membrane Process, Tianjin Polytechnic University, Tianjin 300387 (China); Li, Guodong [The State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China)

    2015-12-15

    Metal-organic frameworks (MOFs) are porous crystalline materials with high potential for applications in fluorescence sensors. In this work, two solvent-induced Zn(II)–based metal-organic frameworks, Zn{sub 3}L{sub 3}(DMF){sub 2} (1) and Zn{sub 3}L{sub 3}(DMA){sub 2}(H{sub 2}O){sub 3} (2) (L=4,4′-stilbenedicarboxylic acid), were investigated as selective sensing materials for detection of nitroaromatic compounds and metal ions. The sensing experiments show that 1 and 2 both exhibit selective fluorescence quenching toward nitroaniline with a low detection limit. In addition, 1 exhibits high selectivity for detection of Fe{sup 3+} and Al{sup 3+} by significant fluorescence quenching or enhancement effect. While for 2, it only exhibits significant fluorescence quenching effect for Fe{sup 3+}. The results indicate that 1 and 2 are both promising fluorescence sensors for detecting and recognizing nitroaniline and metal ions with high sensitivity and selectivity. - Graphical abstract: Two MOFs have been selected as the fluorescence sensing materials for selectively sensing mitroaromatic compounds and metal ions. The high selectivity makes them promising fluorescence sensors for detecting and recognizing nitroaniline and Fe{sup 3+} or Al{sup 3+}.

  12. Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties

    DEFF Research Database (Denmark)

    Jantzen, Christopher; Jørgensen, Henrik L; Duus, Benn R

    2013-01-01

    Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties.......Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties....

  13. 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.

  14. Metal ion levels and revision rates in metal-on-metal hip resurfacing arthroplasty: a comparative study.

    Science.gov (United States)

    Robinson, Patrick G; Wilkinson, Andrew J; Meek, Robert M D

    2014-01-01

    Metal-on-metal (MoM) bearings in hip surgery are related to increased blood levels of metal ions. The nature of the relationship between ion levels and failure is still not fully understood. This study compares three cohorts of patients, 120 patients in each cohort, treated with a hip resurfacing arthroplasty, grouped by brand and diameter of femoral component on average four years postoperatively: Birmingham Hip Resurfacing ≥50 mm, Durom resurfacing ≥50 mm and Durom resurfacing resurfacing than the other two cohorts (P<0.05). The large BHR and large Durom HRA had revision rates of 3.3%. The small Durom HRA had a revision rate of 8.3%. Elevated blood ion levels can indicate a failing MoM bearing. The large BHR and large Durom HRA have similar revision rates yet the large Durom HRA had significantly lower metal ion levels. When similar ion levels were reported for BHR and small Durom the latter had significantly higher revision rates. This suggests ion levels do not absolutely predict the rate of HRA failure. Since MoM generation of metal ions is not the sole reason of failure, regular clinical and radiographic follow-up should also be in place for patients with these joints.

  15. Molecular design of the microbial cell surface toward the recovery of metal ions.

    Science.gov (United States)

    Kuroda, Kouichi; Ueda, Mitsuyoshi

    2011-06-01

    The genetic engineering of microorganisms to adsorb metal ions is an attractive method to facilitate the environmental cleanup of metal pollution and to enrich the recovery of metal ions such as rare metal ions. For the recovery of metal ions by microorganisms, cell surface design is an effective strategy for the molecular breeding of bioadsorbents as an alternative to intracellular accumulation. The cell surface display of known metal-binding proteins/peptides and the molecular design of novel metal-binding proteins/peptides have been performed using a cell surface engineering approach. The adsorption of specific metal ions is the important challenge for the practical recovery of metal ions. In this paper, we discuss the recent progress in surface-engineered bioadsorbents for the recovery of metal ions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Stripping chronopotentiometry for metal ion speciation analysis at a microelectrode

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.

    2002-01-01

    The features of metal ion speciation determination by stripping chronopotentiometry (SCP) at a microelectrode are examined and compared with those of DP-SV. SCP measurements are essentially of a steady-state nature under experimentally achievable conditions and correspond to practically complete

  17. 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 tra

  18. Stripping chronopotentiometry for metal ion speciation analysis at a microelectrode

    NARCIS (Netherlands)

    Leeuwen, van H.P.; Town, R.

    2002-01-01

    The features of metal ion speciation determination by stripping chronopotentiometry (SCP) at a microelectrode are examined and compared with those of DP-SV. SCP measurements are essentially of a steady-state nature under experimentally achievable conditions and correspond to practically complete dep

  19. Separation of metalloproteins using a novel metal ion contaminant sweeping technique and detection of protein-bound copper by a metal ion probe in polyacrylamide gel electrophoresis: distribution of copper in human serum.

    Science.gov (United States)

    Saito, Shingo; Kawashima, Mitsuyoshi; Ohshima, Hiroki; Enomoto, Kazuki; Sato, Makoto; Yoshimura, Hajime; Yoshimoto, Keitaro; Maeda, Mizuo; Shibukawa, Masami

    2013-10-21

    A polyacrylamide gel electrophoresis (PAGE)-based method has been developed, consisting of two types of gel electrophoresis, to obtain an accurate distribution of protein-bound metal ions in biological samples. First, proteins are separated by PAGE without the uptake of contaminant metal ions in the separation field and dissociation of metal ions from the proteins. This is followed by another PAGE for the separation and detection of protein-bound metal ions in small volume samples with high sensitivity in the ppt range using a fluorescent metal probe. The former is a new technique using blue-native (BN) PAGE to electrophoretically sweep all metal contaminants by employing two kinds of chelating agents. These agents form complexes with contaminants in the gel and the separation buffer solution, which migrate towards opposite pole directions, thus lowering the contaminants to below the ppt level during separation. This is termed "Metal Ion Contaminant Sweeping BN-PAGE (MICS-BN-PAGE)". After the separation of proteins under these first metal-free conditions, the metal ions in the gel fractions are eluted, followed by derivatization of copper ions into the metal probe complexes to be separated and determined by fluorescence detection in the second PAGE. In this PAGE-based method, the copper ions bound to ceruloplasmin and superoxide dismutase were quantitatively determined, in addition to the exchangeable albumin-bound copper ions. This system successfully provided distribution maps of protein-copper in human serum. The precise distribution of copper in human serum was investigated, and found to be different from that which is widely accepted.

  20. Advanced Electrolyte/Additive for Lithium-Ion Batteries with Silicon Anode

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuo; He, Meinan; Su, Chi-Cheung; Zhang, Zhengcheng

    2016-07-01

    State-of-the-art lithium-ion batteries (LIBs) are based on a lithium transition metal oxide cathode, a graphite anode and a nonaqueous carbonate electrolyte. To further increase the energy and power density of LIBs, silicon anodes have been intensively explored due to their high theoretical capacity, low operation potential, and low cost. However, the main challenges for Si anode are the large volume change during lithiation/delithiation process and the instability of the solid-electrolyte-interphase associated with this process. Recently, significant progress has been achieved via advanced material fabrication technologies and rational electrolyte design in terms of improving the Coulombic efficiency and capacity retention. In this paper, new developments in advanced electrolyte and additive for LIBs with Si anode were systematically reviewed, and perspectives over future research were suggested.

  1. Removal of toxic metal ions with magnetic hydrogels.

    Science.gov (United States)

    Ozay, Ozgur; Ekici, Sema; Baran, Yakup; Aktas, Nahit; Sahiner, Nurettin

    2009-09-01

    Hydrogels, based on 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) were synthesized via photopolymerization technique and used for the preparation of magnetic responsive composite hydrogels. These composite hydrogels with magnetic properties were further utilized for the removal of toxic metal ions such as Cd(II), Co(II), Fe(II), Pb(II), Ni(II), Cu(II) and Cr(III) from aqueous environments. It was revealed that hydrogel networks with magnetic properties can effectively be utilized in the removal of pollutants. The results verified that magnetic iron particle containing p(AMPS) hydrogel networks provide advantageous over conventional techniques. Langmuir and Freundlich adsorption isotherms were applied for toxic metal removal and both isotherms were fit reasonably well for the metal ion absorptions.

  2. Chitosan removes toxic heavy metal ions from cigarette mainstream smoke

    Science.gov (United States)

    Zhou, Wen; Xu, Ying; Wang, Dongfeng; Zhou, Shilu

    2013-09-01

    This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.

  3. Chitosan Removes Toxic Heavy Metal Ions from Cigarette Mainstream Smoke

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wen; XU Ying; WANG Dongfeng; ZHOU Shilu

    2013-01-01

    This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan.Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages.The mainstream smoke particulate matter was collected by a Cambridge filter pad,digested by a microwave digestor,and then analyzed for contents of heavy metal ions,including As(Ⅲ/Ⅴ),Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),by graphite furnace atomic absorption spectrometry (GFAAS).The results showed that chitosan had a removal effect on Pb(Ⅱ),Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ).Of these,the percent removal of Ni(Ⅱ) was elevated with an increasing dosage of chitosan.Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ),though with poor efficiency for Pb(Ⅱ).Except As(Ⅲ/Ⅴ),all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight.Nonetheless,the percent removal of Cr(Ⅲ/Ⅵ) peaked with a chitosan molecular weight of 200 kDa,followed by a dramatic decrease with an increasing chitosan molecular weight.Generally,chitosan had different removal effects on four out of five tested metal ions,and the percent removal of Cd(Ⅱ),Pb(Ⅱ),Cr(Ⅲ/Ⅵ) and Ni(Ⅱ) was approximately 55%,45%,50%,and 16%,respectively.In a word,chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke,improve cigarette safety,and reduce the harm to smokers.

  4. Electrolyte additive enabled fast charging and stable cycling lithium metal batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Engelhard, Mark H.; Mei, Donghai; Jiao, Shuhong; Polzin, Bryant J.; Zhang, Ji-Guang; Xu, Wu

    2017-03-01

    Batteries using lithium (Li) metal as anodes are considered promising energy storage systems because of their high energy densities. However, safety concerns associated with dendrite growth along with limited cycle life, especially at high charge current densities, hinder their practical uses. Here we report that an optimal amount (0.05 M) of LiPF6 as an additive in LiTFSI-LiBOB dual-salt/carbonate-solvent-based electrolytes significantly enhances the charging capability and cycling stability of Li metal batteries. In a Li metal battery using a 4-V Li-ion cathode at a moderately high loading of 1.75mAh cm(-2), a cyclability of 97.1% capacity retention after 500 cycles along with very limited increase in electrode overpotential is accomplished at a charge/discharge current density up to 1.75 mA cm(-2). The fast charging and stable cycling performances are ascribed to the generation of a robust and conductive solid electrolyte interphase at the Li metal surface and stabilization of the Al cathode current collector.

  5. Rational composition control of mixed-lanthanide metal-organic frameworks by an interfacial reaction with metal ion-doped polymer substrates

    Science.gov (United States)

    Tsuruoka, Takaaki; Miyanaga, Ayumi; Ohhashi, Takashi; Hata, Manami; Takashima, Yohei; Akamatsu, Kensuke

    2017-09-01

    A simple composition control route to mixed-lanthanide metal-organic frameworks (MOFs) was developed based on an interfacial reaction with mixed-lanthanide metal ion-doped polymer substrates. By controlling the composition of lanthanide ion (Eu3+ and Tb3+) dopants in polymer substrates to be used as metal ion precursors and scaffolding for the formation of MOFs, [EuxTb2-x(bdc)3(H2O)4]n crystals with a tunable metal composition could be routinely prepared on polymer substrates. Inductively coupled plasma (ICP) measurements revealed that the composition of the obtained frameworks was almost the same as that of the initial polymer substrates. In addition, the resulting [EuxTb2-x(bdc)3(H2O)4]n crystals showed strong phosphorescence because of Eu3+ transitions, indicating that the energy transfer from Tb3+ to Eu3+ ions in the frameworks could be achieved with high efficiency.

  6. Metal ion levels and lymphocyte counts

    DEFF Research Database (Denmark)

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

    2013-01-01

    . 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...... of cobalt ions in particular on T-cells with 2-year whole-blood cobalt regression coefficients for CD3+ of -0.10 (95% CI: -0.16 to -0.04) × 10(9) cells/parts per billion (ppb), for CD3+CD4+ of -0.06 (-0.09 to -0.03) × 10(9) cells/ppb, and for CD3(+)CD8(+) of -0.02 (-0.03 to -0.00) × 10(9) cells/ppb...

  7. 9-Benzylidene-9H-fluorene Derivatives Linked to Monoaza- 15-crown-5: Synthesis and Metal Ion Sensing

    Institute of Scientific and Technical Information of China (English)

    曹靖; 李阳; 冯俊香

    2012-01-01

    Two kinds of novel styryl chemosensory 2-FMNC and 3-FMNC, were designed and synthesized by an apporiate introduction of 9-benzylidene-9H-fluorene group as fluorophore with the aim at avoiding photoisomerisation. These 9-benzylidene-9H-fluorene derivatives showed the similar selectivity and sensitivity upon addition of metal ions. The sensitivity of FMNC to alkaline earth metal ions was Ba2+〉 Sr2+〉Ca2+≈Mg2+.

  8. Flow characteristics of metallic powder grains for additive manufacturing

    Science.gov (United States)

    Peters, Bernhard; Pozzetti, Gabriele

    2017-06-01

    Directed energy deposition technologies for additive manufacturing such as laser selective melting (SLM) or electron beam melting (EBM) is a fast growing technique mainly due to its flexibility in product design. However, the process is a complex interaction of multi-physics on multiple length scales that are still not entirely understood. A particular challenging task are the flow characteristics of metallic powder ejected as jets from a nozzle and shielded by an inert turbulent gas flow. Therefore, the objective is to describe numerically the complex interaction between turbulent flow and powder grains. In order to include both several physical processes and length scales an Euler-Lagrange technology is applied. Within this framework powder is treated by the Discrete-Element-Method, while gas flow is described by Euler approaches as found in classical Computational Fluid Dynamics (CFD). The described method succeeded in delivering more accuracy and consistency than a standard approach based on the volume averaging technique and therefore, is suited for the solution of problems within an engineering framework.

  9. Flow characteristics of metallic powder grains for additive manufacturing

    Directory of Open Access Journals (Sweden)

    Peters Bernhard

    2017-01-01

    Full Text Available Directed energy deposition technologies for additive manufacturing such as laser selective melting (SLM or electron beam melting (EBM is a fast growing technique mainly due to its flexibility in product design. However, the process is a complex interaction of multi-physics on multiple length scales that are still not entirely understood. A particular challenging task are the flow characteristics of metallic powder ejected as jets from a nozzle and shielded by an inert turbulent gas flow. Therefore, the objective is to describe numerically the complex interaction between turbulent flow and powder grains. In order to include both several physical processes and length scales an Euler-Lagrange technology is applied. Within this framework powder is treated by the Discrete-Element-Method, while gas flow is described by Euler approaches as found in classical Computational Fluid Dynamics (CFD. The described method succeeded in delivering more accuracy and consistency than a standard approach based on the volume averaging technique and therefore, is suited for the solution of problems within an engineering framework.

  10. 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.

  11. 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.

  12. Workshop Report on Additive Manufacturing for Large-Scale Metal Components - Development and Deployment of Metal Big-Area-Additive-Manufacturing (Large-Scale Metals AM) System

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Sudarsanam Suresh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Love, Lonnie J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility; Dehoff, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Manufacturing Demonstration Facility

    2016-05-01

    Additive manufacturing (AM) is considered an emerging technology that is expected to transform the way industry can make low-volume, high value complex structures. This disruptive technology promises to replace legacy manufacturing methods for the fabrication of existing components in addition to bringing new innovation for new components with increased functional and mechanical properties. This report outlines the outcome of a workshop on large-scale metal additive manufacturing held at Oak Ridge National Laboratory (ORNL) on March 11, 2016. The charter for the workshop was outlined by the Department of Energy (DOE) Advanced Manufacturing Office program manager. The status and impact of the Big Area Additive Manufacturing (BAAM) for polymer matrix composites was presented as the background motivation for the workshop. Following, the extension of underlying technology to low-cost metals was proposed with the following goals: (i) High deposition rates (approaching 100 lbs/h); (ii) Low cost (<$10/lbs) for steel, iron, aluminum, nickel, as well as, higher cost titanium, (iii) large components (major axis greater than 6 ft) and (iv) compliance of property requirements. The above concept was discussed in depth by representatives from different industrial sectors including welding, metal fabrication machinery, energy, construction, aerospace and heavy manufacturing. In addition, DOE’s newly launched High Performance Computing for Manufacturing (HPC4MFG) program was reviewed. This program will apply thermo-mechanical models to elucidate deeper understanding of the interactions between design, process, and materials during additive manufacturing. Following these presentations, all the attendees took part in a brainstorming session where everyone identified the top 10 challenges in large-scale metal AM from their own perspective. The feedback was analyzed and grouped in different categories including, (i) CAD to PART software, (ii) selection of energy source, (iii

  13. 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.

  14. Contiguous metal-mediated base pairs comprising two Ag(I) ions.

    Science.gov (United States)

    Megger, Dominik A; Guerra, Célia Fonseca; Hoffmann, Jan; Brutschy, Bernhard; Bickelhaupt, F Matthias; Müller, Jens

    2011-05-27

    The incorporation of transition-metal ions into nucleic acids by using metal-mediated base pairs has proved to be a promising strategy for the site-specific functionalization of these biomolecules. We report herein the formation of Ag(+)-mediated Hoogsteen-type base pairs comprising 1,3-dideaza-2'-deoxyadenosine and thymidine. By defunctionalizing the Watson-Crick edge of adenine, the formation of regular base pairs is prohibited. The additional substitution of the N3 nitrogen atom of adenine by a methine moiety increases the basicity of the exocyclic amino group. Hence, 1,3-dideazaadenine and thymine are able to incorporate two Ag(+) ions into their Hoogsteen-type base pair (as compared with one Ag(+) ion in base pairs with 1-deazaadenine and thymine). We show by using a combination of experimental techniques (UV and circular dichroism (CD) spectroscopies, dynamic light scattering, and mass spectrometry) that this type of base pair is compatible with different sequence contexts and can be used contiguously in DNA double helices. The most stable duplexes were observed when using a sequence containing alternating purine and pyrimidine nucleosides. Dispersion-corrected density functional theory calculations have been performed to provide insight into the structure, formation and stabilization of the twofold metalated base pair. They revealed that the metal ions within a base pair are separated by an Ag···Ag distance of about 2.88 Å. The Ag-Ag interaction contributes some 16 kcal mol(-1) to the overall stability of the doubly metal-mediated base pair, with the dominant contribution to the Ag-Ag bonding resulting from a donor-acceptor interaction between silver 4d-type and 4s orbitals. These Hoogsteen-type base pairs enable a higher functionalization of nucleic acids with metal ions than previously reported metal-mediated base pairs, thereby increasing the potential of DNA-based nanotechnology.

  15. Ion conducting polymers and polymer blends for alkali metal ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. A novel Schiff base: Synthesis, structural characterisation and comparative sensor studies for metal ion detections.

    Science.gov (United States)

    Köse, Muhammet; Purtas, Savas; Güngör, Seyit Ali; Ceyhan, Gökhan; Akgün, Eyup; McKee, Vickie

    2015-02-05

    A novel Schiff base ligand was synthesized by the condensation reaction of 2,6-diformylpyridine and 4-aminoantipyrine in MeOH and characterised by its melting point, elemental analysis, FT-IR, (1)H, (13)C NMR and mass spectroscopic studies. Molecular structure of the ligand was determined by single crystal X-ray diffraction technique. The electrochemical properties of the Schiff base ligand were studied in different solvents at various scan rates. Sensor ability of the Schiff base ligand was investigated by colorimetric and fluorometric methods. Visual colour change of the ligand was investigated in MeOH solvent in presence of various metal ions Na(+), Mg(2+), Al(3+), K(+), Cr(3+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Pb(2+). Upon addition of Al(3+) ion into a MeOH solution of the ligand, an orange colour developed which is detectable by naked eye. Fluorescence emission studies showed that the ligand showed single emission band at 630-665nm upon excitation at 560nm. Addition of metal ions Na(+), Mg(2+), K(+), Cr(3+), Mn(2+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Pb(2+) (1:1M ratio) cause fluorescence quenching, however addition of Al(+3) resulted in an increase in fluorescence intensity. No significant variation was observed in the fluorescence intensity caused by Al(3+) in presence of other metal ions. Therefore, the Schiff base ligand can be used for selective detection of Al(3+) ions in the presence of the other metal ions studied.

  17. Ion beam mixing isotopic metal bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Fell, C.J. [Newcastle Univ., NSW (Australia). Dept. of Physics; Kenny, M.J. [CSIRO, Lindfield, NSW (Australia). Div. of Applied Physics

    1993-12-31

    In order to obtain an insight into the mechanisms of ion-solid interactions, bilayer targets can be prepared from two different isotopes. A mixing study SIMS is to be carried out using specially grown monocrystalline bilayers of {sup 58}Ni / {sup 60}Ni. An important aspect of the work is the preparation of high quality single-crystal thin films. The Ni layers will be grown on the (110) surface of pure Ni and verified for crystallinity using Reflection High-Energy Electron Diffraction and Rutherford Backscattering channelling analysis. The Pd bilayers will be grown on a Pd (100) surface. RHEED will be used to confirm the two-dimensional crystallinity of the surface before and after deposition of each layer, and channelling used to confirm bulk film crystallinity. Single crystal substrates are currently being prepared. Analysis of the Ni (110) surface using RHEED at 9 kV shows a streak spacing which corresponds to a lattice spacing of 2.47 {+-} 0.09 Angstroms. 9 refs., 1 fig.

  18. Optical studies of ion-beam synthesized metal alloy nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Magudapathy, P., E-mail: pmp@igcar.gov.in; Srivatsava, S. K.; Gangopadhyay, P.; Amirthapandian, S.; Sairam, T. N.; Panigrahi, B. K. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603 102 India (India)

    2015-06-24

    Au{sub x}Ag{sub 1-x} alloy nanoparticles with tunable surface plasmon resonance (SPR) have been synthesized on a silica glass substrate. A small Au foil on an Ag foil is irradiated as target substrates such that ion beam falls on both Ag foil and Au foils. Silica slides are kept at an angle ∼45° with respect to the metallic foils. While irradiating the metallic foils with 100 keV Ar{sup +} ions, sputtered Au and Ag atoms get deposited on the silica-glass. In this configuration the foils have been irradiated by Ar{sup +} ions to various fluences at room temperature and the sputtered species are collected on silica slides. Formation of Au{sub x}Ag{sub 1-x} nanoparticles has been confirmed from the optical absorption measurements. With respect to the exposure area of Au and Ag foils to the ion beam, the SPR peak position varies from 450 to 500 nm. Green photoluminescence has been observed from these alloy metal nanoparticles.

  19. Peptide immobilisation on porous silicon surface for metal ions detection.

    Science.gov (United States)

    Sam, Sabrina S; Chazalviel, Jean-Noël Jn; Gouget-Laemmel, Anne Chantal Ac; Ozanam, François F; Etcheberry, Arnaud A; Gabouze, Nour-Eddine N

    2011-01-01

    In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis) peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl-N'-(3-dimethylaminopropyl)-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization.The property of peptides to form stable complexes with metal ions is exploited to achieve metal-ion recognition by the peptide-modified PSi-based biosensor. An electrochemical study of the GlyHisGlyHis-modified PSi electrode is achieved in the presence of copper ions. The recorded cyclic voltammograms show a quasi-irreversible process corresponding to the Cu(II)/Cu(I) couple. The kinetic factors (the heterogeneous rate constant and the transfer coefficient) and the stability constant of the complex formed on the porous silicon surface are determined. These results demonstrate the potential role of peptides grafted on porous silicon in developing strategies for simple and fast detection of metal ions in solution.

  20. Peptide immobilisation on porous silicon surface for metal ions detection

    Directory of Open Access Journals (Sweden)

    Chazalviel Jean-Noël

    2011-01-01

    Full Text Available Abstract In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl-N'-(3-dimethylaminopropyl-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization. The property of peptides to form stable complexes with metal ions is exploited to achieve metal-ion recognition by the peptide-modified PSi-based biosensor. An electrochemical study of the GlyHisGlyHis-modified PSi electrode is achieved in the presence of copper ions. The recorded cyclic voltammograms show a quasi-irreversible process corresponding to the Cu(II/Cu(I couple. The kinetic factors (the heterogeneous rate constant and the transfer coefficient and the stability constant of the complex formed on the porous silicon surface are determined. These results demonstrate the potential role of peptides grafted on porous silicon in developing strategies for simple and fast detection of metal ions in solution.

  1. Peptide immobilisation on porous silicon surface for metal ions detection

    Science.gov (United States)

    Sam, Sabrina S.; Chazalviel, Jean-Noël Jn; Gouget-Laemmel, Anne Chantal Ac; Ozanam, François F.; Etcheberry, Arnaud A.; Gabouze, Nour-Eddine N.

    2011-06-01

    In this work, a Glycyl-Histidyl-Glycyl-Histidine (GlyHisGlyHis) peptide is covalently anchored to the porous silicon PSi surface using a multi-step reaction scheme compatible with the mild conditions required for preserving the probe activity. In a first step, alkene precursors are grafted onto the hydrogenated PSi surface using the hydrosilylation route, allowing for the formation of a carboxyl-terminated monolayer which is activated by reaction with N-hydroxysuccinimide in the presence of a peptide-coupling carbodiimide N-ethyl- N'-(3-dimethylaminopropyl)-carbodiimide and subsequently reacted with the amino linker of the peptide to form a covalent amide bond. Infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy are used to investigate the different steps of functionalization. The property of peptides to form stable complexes with metal ions is exploited to achieve metal-ion recognition by the peptide-modified PSi-based biosensor. An electrochemical study of the GlyHisGlyHis-modified PSi electrode is achieved in the presence of copper ions. The recorded cyclic voltammograms show a quasi-irreversible process corresponding to the Cu(II)/Cu(I) couple. The kinetic factors (the heterogeneous rate constant and the transfer coefficient) and the stability constant of the complex formed on the porous silicon surface are determined. These results demonstrate the potential role of peptides grafted on porous silicon in developing strategies for simple and fast detection of metal ions in solution.

  2. [Applications of metal ions and their complexes in medicine I].

    Science.gov (United States)

    Nagy, László; Csintalan, Gabriella; Kálmán, Eszter; Sipos, Pál; Szvetnik, Attila

    2003-01-01

    The "inorganic medical chemistry" is a rapidly developing field with enormous potential for applications, which offers new possibilities to the pharmaceutical industry. For example, the titanocene dichloride is already in clinical use, and antimetastatic activity of a range of Ru(III) complexes is also well established. There are ways to minimize the toxicity of Gd(III) complexes and therefore they can be safely injected as MRI contrast agents. The so called "ligand design" allows paramagnetic ions to be targeted to specific organs. Such designed ligands also enable the targeting of radiodiagnostic (99mTc) and radiotherapeutic (186Re) isotopes. There is a significant progress in understanding the coordination chemistry and biochemistry of metal ion(s) containing complexes such as Au antiarthritic and Bi antiulcer drugs. Further, currently developing areas include Mn (SOD mimics), V (insulin mimics), Ru (NO scavengers), Ln-based photosensitizers, metal-targeted organic agents and the Fe overload. The expanding knowledge of the role of metals in biochemistry is expected to provide scope for the design of new drugs in many other areas too, for example neuropharmaceutical and antiaffective agents. Progress in coordination chemistry is strongly dependent on understanding not only the thermodynamics of reactions, but also the kinetics of metal complexes under biologically relevant conditions.

  3. New Catalytic DNA Biosensors for Radionuclides and Metal ion

    Energy Technology Data Exchange (ETDEWEB)

    Yi Lu

    2008-03-01

    We aim to develop new DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides, such as uranium, technetium, and plutonium, and metal contaminants, such as lead, chromium, and mercury. The sensors will be highly sensitive and selective. They will be applied to on-site, real-time assessment of concentration, speciation, and stability of the individual contaminants before and during bioremediation, and for long-term monitoring of DOE contaminated sites. To achieve this goal, we have employed a combinatorial method called “in vitro selection” to search from a large DNA library (~ 1015 different molecules) for catalytic DNA molecules that are highly specific for radionuclides or other metal ions through intricate 3-dimensional interactions as in metalloproteins. Comprehensive biochemical and biophysical studies have been performed on the selected DNA molecules. The findings from these studies have helped to elucidate fundamental principles for designing effective sensors for radionuclides and metal ions. Based on the study, the DNA have been converted to fluorescent or colorimetric sensors by attaching to it fluorescent donor/acceptor pairs or gold nanoparticles, with 11 part-per-trillion detection limit (for uranium) and over million fold selectivity (over other radionuclides and metal ions tested). Practical application of the biosensors for samples from the Environmental Remediation Sciences Program (ERSP) Field Research Center (FRC) at Oak Ridge has also been demonstrated.

  4. Additive Manufacturing of Functional Elements on Sheet Metal

    Science.gov (United States)

    Schaub, Adam; Ahuja, Bhrigu; Butzhammer, Lorenz; Osterziel, Johannes; Schmidt, Michael; Merklein, Marion

    Laser Beam Melting (LBM) process with its advantages of high design flexibility and free form manufacturing methodology is often applied limitedly due to its low productivity and unsuitability for mass production compared to conventional manufacturing processes. In order to overcome these limitations, a hybrid manufacturing methodology is developed combining the additive manufacturing process of laser beam melting with sheet forming processes. With an interest towards aerospace and medical industry, the material in focus is Ti-6Al-4V. Although Ti-6Al-4V is a commercially established material and its application for LBM process has been extensively investigated, the combination of LBM of Ti-6Al-4V with sheet metal still needs to be researched. Process dynamics such as high temperature gradients and thermally induced stresses lead to complex stress states at the interaction zone between the sheet and LBM structure. Within the presented paper mechanical characterization of hybrid parts will be performed by shear testing. The association of shear strength with process parameters is further investigated by analyzing the internal structure of the hybrid geometry at varying energy inputs during the LBM process. In order to compare the hybrid manufacturing methodology with conventional fabrication, the conventional methodologies subtractive machining and state of the art Laser Beam Melting is evaluated within this work. These processes will be analyzed for their mechanical characteristics and productivity by determining the build time and raw material consumption for each case. The paper is concluded by presenting the characteristics of the hybrid manufacturing methodology compared to alternative manufacturing technologies.

  5. Low energy ion beam assisted growth of metal multilayers

    Science.gov (United States)

    Quan, Junjie

    Vapor deposited metal multilayers have attracted a great deal of interest in recent years because they offer extraordinary strength, hardness, heat resistance, and unexpected new properties like high reflectivity and spin-dependent conductivity. The giant magnetoresistance effects discovered in Fe/Cr artificial superstructures in 1988 stimulated a large number of studies on the electronic transport properties of spintronic materials because of their important applications in highly sensitive magnetic sensors, nonvolatile random access memories, and the data storage industry in general. Magnetic multilayers allow exploitation of unique micromagnetic, magnetooptic, and magnetoelectronic phenomena that cannot be realized using conventional materials. For example, if ferromagnetic layers (such as CoFe) with a thicknesses of 5-7 nm are separated by a non-magnetic spacer (such as Cu or AlOx) of an appropriate thickness (1-3 nm), they can exhibit large changes in their electrical resistance when a magnetic field is applied. These changes are caused mainly by spin-dependent conduction electron scattering at magnetic multilayer interfaces. Many experimental and theoretical works have sought to promote a basic understanding of the effect of atomic structure in thin film multilayers upon spin dependent transport. It has been found that interfacial imperfections, such as interfacial roughness and interlayer mixing, dramatically reduce the properties exploited for spintronic applications. A combination of computer modeling and experiments has been used to discover more effective ways to control the interfacial structures of metal multilayers. Earlier atomic simulations had indicated that it is very important to control adatom energy during deposition in order to improve interface properties. Based on these ideas, this dissertation has investigated the effects of low energy ion assistance during metal multilayer deposition. Using molecular dynamics modeling, the effects of ion

  6. Cubic nitrides of the sixth group of transition metals formed by nitrogen ion irradiation during metal condensation

    Energy Technology Data Exchange (ETDEWEB)

    Ensinger, W. [Augsburg Univ. (Germany). Inst. fuer Physik; Kiuchi, M. [Osaka National Research Institute, Midorigaoka 1-8-31, Ikeda, Osaka 563 (Japan)

    1996-10-01

    Nitrogen-containing phases of chromium, molybdenum and tungsten were formed by evaporation of the metal under simultaneous nitrogen ion irradiation. With gradually increasing ion irradiation intensity, chromium forms initially Cr and Cr{sub 2}N phase mixtures, then additionally CrN appears, and at the highest intensities pure CrN films are formed. Molybdenum also forms pure nitride MoN under intense ion bombardment. However, in this case two different crystal structures are found, the stable hexagonal phase and the metastable cubic high-temperature phase. The latter is favoured under intense ion irradiation. In the case of tungsten, even at the highest intensities, only phase mixtures of W and W{sub 2}N were formed. These observed differences can be explained by the low reactivity of these metals towards nitrogen and the low chemical stability of the nitrides, particularly of WN. The metastable high-temperature structure of MoN is formed under the particular conditions of ion bombardment with rapid energy dissipation. (orig.)

  7. A novel dithiourea and its response to metal ions

    Institute of Scientific and Technical Information of China (English)

    Lu Yuan; Hong Zhong; Li Oing Li; Jing Jing Xiao

    2012-01-01

    The synthesis,characterization,and its response to metal ions of a novel thiourea N,N'-diethoxycarbonyl-N'',N'''-(1,2-ethylidene) dithiourea was reported.The results show that this dithiourea with new structure can react with Cu2+ and Ni2+ separately,and has a best selectivity to Fe3+ ions.Bench-scale flotation tests were also carried out,verifying it has higher copper flotation recovery and better selectivity to sulfide ores containing Cu compared with universal collectors.

  8. Peripheral collisions of highly charged ions with metal clusters

    Institute of Scientific and Technical Information of China (English)

    Zhang Cheng-Jun; Hu Bi-Tao; Luo Xian-Wen

    2012-01-01

    Within the framework of the dynamical classical over-barrier model,the soft collisions between slow highly charged ions(SHCIs)Ar17+ and the large copper clusters under large impact parameters have been studied in this paper.We present the dominant mechanism of the electron transfer between SHCls and a large metal cluster by computational simulation.The evolution of the occupation of projectile ions,KLχ satellite lines,X-ray yields,Auger electron spectrum and scattering angles are provided.

  9. Solid-liquid solvent extraction of metal ions

    Institute of Scientific and Technical Information of China (English)

    Bo Peng; Haiyan Fan; Jinzhang Gao

    2003-01-01

    An overview of extraction of some trace metal ions using molten solvent (low melting substance) during last two decadesis presented. The development of this technique since its inception is briefly traced. The comparison of extraction efficiency, thermo-dynamics and kinetics mainly involving extraction of rare earth ions between molten solvent extraction at high temperature and usualliquid-liquid extraction at room temperature are discussed in detail. The various parameters obtained from the previous and presentstudies such as equilibrium extraction constant Kex, pH1/2, thermodynamic and kinetic data are displayed in tabular form. Finally, thecurrent demands, disadvantages and future prospects are also evaluated.

  10. Removal of Heavy Metal Ions From Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    maziar noei

    2014-12-01

    Full Text Available The removal of Zn(II, V(II,  by  silica aerogel has been found to be concentration, , contact time, adsorbent dose and temperature dependent. ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on silica aerogel  was satisfied. The applicability of the Lagergren kinetic model has also been investigated. Thermodynamic constant (Kad , standard free energy ( ∆G0 ,enthalpy (∆H0 and entropy (∆S0 were calculated for predicting the nature of adsorption

  11. Reducing of internal resistance lithium ion battery using glucose addition

    Energy Technology Data Exchange (ETDEWEB)

    Salim, Andri Pratama; Hafidlullah, Noor; Purwanto, Agus, E-mail: aguspurw@gmail.com [Research Group of Battery & Advanced Material, Department of Chemical Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta Indonesia 57126 (Indonesia)

    2016-02-08

    There are two indicators of battery performance, i.e : capacity and the internal resistance of battery. In this research, the affect of glucose addition to decrease the internal resistance of lithium battery was investigated. The ratio of glucose addition were varied at weight ratio 1%, 3%, and 5% and one mixtures without glucose addition. Lithium ferri phosphate (LiFePO{sub 4}), polyvinylidene fluoride (PVDF), acetylene black (AB) and glucose were materials that used in this study. Both of mixtures were mixed in the vacuum mixer until became homogeneous. The slurry was coated on an aluminium foil sheet and the coated thickness was 200 µm. The performance of battery lithium was examined by Eight Channel Battery Analyzer and the Internal resistance was examined by Internal Resistance of Battery Meter. The result from all analyzer were showed that the internal resistance reduced as well as the battery capacity. The best internal resistance value is owned by mixtures with 3wt% ratio glucose addition. It has an internal resistance value about 64 miliohm.

  12. Statistical evaluation of biogeochemical variables affecting spatiotemporal distributions of multiple free metal ion concentrationsin an urban estuary

    Science.gov (United States)

    Free metal ion concentrations have been recognized as a better indicator of metal bioavailability in aquatic environments than total dissolved metal concentrations. However, our understanding of the determinants of free ion concentrations, especially in a metal mixture, is limite...

  13. MRI probes for sensing biologically relevant metal ions.

    Science.gov (United States)

    Bonnet, Célia S; Tóth, Eva

    2010-03-01

    Given the important role of metal ions in fundamental biological processes, the visualization of their concentration in living animals by repeatable, noninvasive imaging techniques, such as MRI, would be highly desirable. A large number of metal-responsive MRI contrast agents, the majority based on Gd(3+) complexes, have been reported in recent years. The contrast-enhancing properties (relaxivity) of a Gd(3+) complex can be most conveniently modulated by interaction with the sensed metal cation via changes in the number of water molecules bound directly to Gd(3+) or changes in the size of the complex, which represent the two major strategies to develop metal sensitive MRI probes. Here, we survey paramagnetic lanthanide complexes involving Gd(3+) agents and paramagnetic chemical exchange saturation transfer probes designed to detect the most important endogenous metal ions: calcium, zinc, iron and copper. Future work will likely focus on extending applications of these agents to living animals, as well as on exploring new ways of creating molecular MRI probes in order to meet requirements such as higher specificity or lower detection limits.

  14. 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.

  15. Luminescence enhancement of rare earth ions by metal nanostructures

    Institute of Scientific and Technical Information of China (English)

    G.A.Denisenko

    2009-01-01

    Well-ordered metal structures,i.e.arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used.These arrays were prepared by the metal evaporation on track membranes.Calculations of resonance frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips.They were used to discuss experimental results for media with Eu(NO3)3·6H2O salt basing on data for bulk silver dielectric function.

  16. The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

    Science.gov (United States)

    Danford, M. D.

    1993-01-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  17. Polydopamine-mediated surface-functionalization of graphene oxide for heavy metal ions removal

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Zhihui [Nano-Bionics Division and i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Feng; Wang, Dong; Liu, Xia [Nano-Bionics Division and i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Jin, Jian, E-mail: jjin2009@sinano.ac.cn [Nano-Bionics Division and i-LAB, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2015-04-15

    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{sup 2+}, Cd{sup 2+}, Pb{sup 2+}, Hg{sup 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{sup 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{sup 2+}, Cd{sup 2+}, Pb{sup 2+}, and Hg{sup 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.

  18. Selective retention of basic compounds by metal aquo-ion affinity chromatography.

    Science.gov (United States)

    Asakawa, Yoshiki; Yamamoto, Eiichi; Asakawa, Naoki

    2014-10-01

    A novel metal aquo-ion affinity chromatography has been developed for the analysis of basic compounds using heat-treated silica gel containing hydrated metal cations (metal aquo-ions) as the packing material. The packing materials of the metal aquo-ion affinity chromatography were prepared by the immobilization of a single metal component such as Fe(III), Al(III), Ag(I), and Ni(II) on silica gel followed by extensive heat treatment. The immobilized metals form aquo-ions to present cation-exchange ability for basic analytes and the cation-exchange ability for basic analytes depends on pKa of the immobilized metal species. In the present study, to evaluate the retention characteristics of metal aquo-ion affinity chromatography, the on-line solid-phase extraction of drugs was investigated. Obtained data clearly evidence the selective retention capability of metal aquo-ion affinity chromatography for basic analytes with sufficient capacity.

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

    NARCIS (Netherlands)

    Janssen, R.P.T.

    1995-01-01

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

  20. Metal-assisted secondary ion mass spectrometry using atomic (Ga+, In+) and fullerene projectiles.

    Science.gov (United States)

    Delcorte, A; Yunus, S; Wehbe, N; Nieuwjaer, N; Poleunis, C; Felten, A; Houssiau, L; Pireaux, J-J; Bertrand, P

    2007-05-15

    The advantages and drawbacks of using either monatomic or buckminsterfullerene primary ions for metal-assisted secondary ion mass spectrometry (MetA-SIMS) are investigated using a series of organic samples including additive molecules, polyolefins, and small peptides. Gold deposition is mostly performed by sputter-coating, and in some cases, the results are compared to those of thermal evaporation (already used in a previous article: Delcorte, A.; Médard, N.; Bertrand, P. Anal. Chem. 2002, 74, 4955). The microstructure of the gold-covered sample surfaces is assessed by scanning and transmission electron microscopies. The merits of the different sets of experimental conditions are established via the analysis of fragment and parent-like ion yields. For most of the analyzed samples, the highest yields of fragment and parent-like ions are already reached with the sole use of C60+ projectiles. Metallization of the sample does not lead to a significant additional enhancement. For polyethylene and polypropylene, however, gold metallization associated with Ga+/In+ projectiles appears to be the only way to observe large cationized, sample-specific chain segments (m/z approximately 1000-2000). A detailed study of the polypropylene mass spectra as a function of gold coverage shows that the dynamics of yield enhancement by metal nanoparticles is strongly dependent on the choice of the projectile, e.g., a pronounced increase with Ga+ and a slow decay with C60+. The cases of Irganox 1010, a polymer antioxidant, and leucine enkephalin, a small peptide, allow us to investigate the specific influence of the experimental conditions on the emission of parent(like) ions such as M+, (M + Na)+, and (M + Au)+. The results show a dependence on both the type of sample and the considered secondary ion. Using theoretical and experimental arguments, the discussion identifies some of the mechanisms underlying the general trends observed in the results. Guidelines concerning the choice of the

  1. Infrared Spectroscopy of Metal Ion Complexes: Models for Metal Ligand Interactions and Solvation

    Science.gov (United States)

    Duncan, Michael

    2006-03-01

    Weakly bound complexes of the form M^+-Lx (M=Fe, Ni, Co, etc.; L=CO2, C2H2, H2O, benzene, N2) are prepared in supersonic molecular beams by laser vaporization in a pulsed-nozzle cluster source. These species are mass analyzed and size-selected in a reflectron time-of-flight mass spectrometer. Clusters are photodissociated at infrared wavelengths with a Nd:YAG pumped infrared optical parametric oscillator/amplifier (OPO/OPA) laser or with a tunable infrared free-electron laser. M^+-(CO2)x complexes absorb near the free CO2 asymmetric stretch near 2349 cm-1 but with an interesting size dependent variation in the resonances. Small clusters have blue-shifted resonances, while larger complexes have additional bands due to surface CO2 molecules not attached to the metal. M^+(C2H2)n complexes absorb near the C-H stretches in acetylene, but resonances in metal complexes are red-shifted with repect to the isolated molecule. Ni^+ and Co^+ complexes with acetylene undergo intracluster cyclization reactions to form cyclobutadiene. Transition metal water complexes are studied in the O-H stretch region, and partial rotational structure can be measured. M^+(benzene) and M^+(benzene)2 ions (M=V, Ti, Al) represent half-sandwich and sandwich species, whose spectra are measured near the free benzene modes. These new IR spectra and their assignments will be discussed as well as other new IR spectra for similar complexes.

  2. Synthesis of metallic glasses and metallic glass based composites in the Cu-Mo-Hf system by ion beam mixing

    Institute of Scientific and Technical Information of China (English)

    BAI Xue; WANG TongLe; CUI YuanYuan; DING Ning; LI JiaHao; LIU BaiXin

    2012-01-01

    Single-phase and dual-phase metallic glasses as well as metallic glass based composites were synthesized in the Cu-Mo-Hf ternary metal system by 200 keV xenon ion beam mixing of far-from-equilibrium.It was found that Mo-Hf-based and Cu-Mo-based single-phase metallic glasses could be obtained at compositions around Cu17Mo20Hf63 and Cu34Mo57Hf9,respectively.Interestingly,at the nearly equal-atomic stoichiometry of Cu38Mo31Hf31,a dual-phase Cu-Mo-Hf metallic glass,consisting both of the Mo-Hf-based and Cu-Mo-based phases,was first obtained at relatively low irradiation doses ranging from (1-5)×1015 Xe+/cm2,and a single-phase metallic glass was eventually obtained at a dose of 7×1015 Xe+/cm2.In addition,two glass-based composites were obtained at the compositions of Cu14Mo62Hf24 and Cu77Mo14Hf9,and they consisted of the Mo-Hf based and Cu-Mo based metallic glasses,dissolved with some uniformly distributed BCC Mo-based and FCC Cu-based crystalline solid solutions,respectively.The formation mechanism of the above described non-equilibrium alloy phases was also discussed in terms of the atomic collision theory.

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This article deals with the determination of the adsorption properties of metal ions and humic acid in water 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 carried out by the batch method at room temperature. Adsorption of heavy metal ions (such as Cu2+, Cd2+) 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 Cu2+, Cd2+,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.

  4. Lithium metal doped electrodes for lithium-ion rechargeable chemistry

    Science.gov (United States)

    Liu, Gao; Battaglia, Vince; Wang, Lei

    2016-09-13

    An embodiment of the invention combines the superior performance of a polyvinylidene difluoride (PVDF) or polyethyleneoxide (POE) binder, the strong binding force of a styrene-butadiene (SBR) binder, and a source of lithium ions in the form of solid lithium metal powder (SLMP) to form an electrode system that has improved performance as compared to PVDF/SBR binder based electrodes. This invention will provide a new way to achieve improved results at a much reduced cost.

  5. Metal ions: supporting actors in the playbook of small ribozymes.

    Science.gov (United States)

    Johnson-Buck, Alexander E; McDowell, Sarah E; Walter, Nils G

    2011-01-01

    Since the 1980s, several small RNA motifs capable of chemical catalysis have been discovered. These small ribozymes, composed of between approximately 40 and 200 nucleotides, have been found to play vital roles in the replication of subviral and viral pathogens, as well as in gene regulation in prokaryotes, and have recently been discovered in noncoding eukaryotic RNAs. All of the known natural small ribozymes - the hairpin, hammerhead, hepatitis delta virus, Varkud satellite, and glmS ribozymes--catalyze the same self-cleavage reaction as RNase A, resulting in two products, one bearing a 2'-3' cyclic phosphate and the other a 5'-hydroxyl group. Although originally thought to be obligate metalloenzymes like the group I and II self-splicing introns, the small ribozymes are now known to support catalysis in a wide variety of cations that appear to be only indirectly involved in catalysis. Nevertheless, under physiologic conditions, metal ions are essential for the proper folding and function of the small ribozymes, the most effective of these being magnesium. Metal ions contribute to catalysis in the small ribozymes primarily by stabilizing the catalytically active conformation, but in some cases also by activating RNA functional groups for catalysis, directly participating in catalytic acid-base chemistry, and perhaps by neutralizing the developing negative charge of the transition state. Although interactions between the small ribozymes and cations are relatively nonspecific, ribozyme activity is quite sensitive to the types and concentrations of metal ions present in solution, suggesting a close evolutionary relationship between cellular metal ion homeostasis and cation requirements of catalytic RNAs, and perhaps RNA in general.

  6. Systems and Methods for Fabricating Objects Including Amorphous Metal Using Techniques Akin to Additive Manufacturing

    Science.gov (United States)

    Hofmann, Douglas (Inventor)

    2017-01-01

    Systems and methods in accordance with embodiments of the invention fabricate objects including amorphous metals using techniques akin to additive manufacturing. In one embodiment, a method of fabricating an object that includes an amorphous metal includes: applying a first layer of molten metallic alloy to a surface; cooling the first layer of molten metallic alloy such that it solidifies and thereby forms a first layer including amorphous metal; subsequently applying at least one layer of molten metallic alloy onto a layer including amorphous metal; cooling each subsequently applied layer of molten metallic alloy such that it solidifies and thereby forms a layer including amorphous metal prior to the application of any adjacent layer of molten metallic alloy; where the aggregate of the solidified layers including amorphous metal forms a desired shape in the object to be fabricated; and removing at least the first layer including amorphous metal from the surface.

  7. Magnetic field effect in photodetachment from negative ion in electric field near metal surface

    Institute of Scientific and Technical Information of China (English)

    Tang Tian-Tian; Wang De-Hua; Huang Kai-Yun; Wang Shan-Shan

    2011-01-01

    Based on the closed-orbit theory, the magnetic field effect in the photodetachment of negative ion in the electric field near a metal surface is studied for the first time. The results show that the magnetic field can produce a significant effect on the photodetachment of negative ion near a metal surface. Besides the closed orbits previously found by Du et al. for the H-in the electric field near a metal surface (J. Phys. B 43 035002 (2010)), some additional closed orbits are produced due to the effect of magnetic field. For a given ion-surface distance and an electric field strength, the cross section depends sensitively on the magnetic field strength. As the magnetic field strength is very small, its influence can be neglected. With the increase of the magnetic field strength, the number of the closed orbits increases greatly and the oscillation in the cross section becomes much more complex. Therefore we can control the photodetachment cross section of the negative ion by changing the magnetic field strength. We hope that our results may guide future experimental studies for the photodetachment process of negative ion in the presence of external fields and surfaces.

  8. Delineating ion-ion interactions by electrostatic modeling for predicting rhizotoxicity of metal mixtures to lettuce Lactuca sativa.

    Science.gov (United States)

    Le, T T Yen; Wang, Peng; Vijver, Martina G; Kinraide, Thomas B; Hendriks, A Jan; Peijnenburg, Willie J G M

    2014-09-01

    Effects of ion-ion interactions on metal toxicity to lettuce Lactuca sativa were studied based on the electrical potential at the plasma membrane surface (ψ0 ). Surface interactions at the proximate outside of the membrane influenced ion activities at the plasma membrane surface ({M(n+)}0). At a given free Cu(2+) activity in the bulk medium ({Cu(2+)}b), additions of Na(+), K(+), Ca(2+), and Mg(2+) resulted in substantial decreases in {Cu(2+)}0. Additions of Zn(2+) led to declines in {Cu(2+)}0, but Cu(2+) and Ag(+) at the exposure levels tested had negligible effects on the plasma membrane surface activity of each other. Metal toxicity was expressed by the {M(n+)}0 -based strength coefficient, indicating a decrease of toxicity in the order: Ag(+)  > Cu(2+)  > Zn(2+). Adsorbed Na(+), K(+), Ca(2+), and Mg(2+) had significant and dose-dependent effects on Cu(2+) toxicity in terms of osmolarity. Internal interactions between Cu(2+) and Zn(2+) and between Cu(2+) and Ag(+) were modeled by expanding the strength coefficients in concentration addition and response multiplication models. These extended models consistently indicated that Zn(2+) significantly alleviated Cu(2+) toxicity. According to the extended concentration addition model, Ag(+) significantly enhanced Cu(2+) toxicity whereas Cu(2+) reduced Ag(+) toxicity. By contrast, the response multiplication model predicted insignificant effects of adsorbed Cu(2+) and Ag(+) on the toxicity of each other. These interactions were interpreted using ψ0, demonstrating its influence on metal toxicity.

  9. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils.

    Science.gov (United States)

    Li, Yong-Tao; Becquer, Thierry; Dai, Jun; Quantin, Cécile; Benedetti, Marc F

    2009-04-01

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils.

  10. Potential release of in vivo trace metals from metallic medical implants in the human body: from ions to nanoparticles--a systematic analytical review.

    Science.gov (United States)

    Matusiewicz, Henryk

    2014-06-01

    Metal ion release from metallic materials, e.g. metallic alloys and pure metals, implanted into the human body in dental and orthopedic surgery is becoming a major cause for concern. This review briefly provides an overview of both metallic alloys and pure metals used in implant materials in dental and orthopedic surgery. Additionally, a short section is dedicated to important biomaterials and their corrosive behavior in both real solutions and various types of media that model human biological fluids and tissues. The present review gives an overview of analytical methods, techniques and different approaches applied to the measurement of in vivo trace metals released into body fluids and tissues from patients carrying metal-on-metal prostheses and metal dental implants. Reference levels of ion concentrations in body fluids and tissues that have been determined by a host of studies are compiled, reviewed and presented in this paper. Finally, a collection of published clinical data on in vivo released trace metals from metallic medical implants is included. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  11. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    DEFF Research Database (Denmark)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouther L.J.

    2013-01-01

    is improved by the addition of divalent metal ions (unpublished results). The stabilizing effect of Zn2+ was by far superior compared to that of Mg2+. In addition, it was found that stabilization correlated well with the ability of the divalent metal ions to interact with oxytocin in aspartate buffer...... favorable. These interactions may explain the protection of the disulfide bridge against intermolecular reactions that lead to dimerization.Mg or Zn, using 2D NOESY, TOCSY, H-C HSQC and H- N HSQC NMR spectroscopy. Almost all H, C and N resonances of oxytocin could be assigned using HSQC spectroscopy...... that the carboxylate group of aspartate neutralizes the positive charge of the N-terminus of Cys, allowing the interactions with Zn to become more favorable. These interactions may explain the protection of the disulfide bridge against intermolecular reactions that lead to dimerization....

  12. Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Nicholas B. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln11]-amyloid β-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will

  13. Enhancement of Platinum Cathode Catalysis by Addition of Transition Metals

    Science.gov (United States)

    Duong, Hung Tuan

    2009-01-01

    The sluggish kinetics of oxygen reduction reaction (ORR) contributes significantly to the loss of cathode overpotential in fuel cells, thus requiring high loadings of platinum (Pt), which is an expensive metal with limited supply. However, Pt and Pt-based alloys are still the best available electrocatalysts for ORR thus far. The research presented…

  14. Laser ion acceleration from a double-layer metal foil

    Energy Technology Data Exchange (ETDEWEB)

    Lecz, Zsolt

    2013-11-12

    -temperature plasma and the consequent proton acceleration in one dimension. We omit the detailed dynamics of the laser-plasma interaction by assuming a preheated electron distribution. With our 1D electrostatic simulations we investigate the influence of the proton layer thickness on the TNSA energy spectrum. Additionally we investigate the divergence of the protons using 2D simulations: In these we simulate the heating of the electrons by the laser pulse. Numerical studies in this work were carried out using a Particle-in-Cell (PIC) plasma simulation code (VORPAL). The target is defined as a single-ionized plasma with a doublelayer structure: a bulk layer of heavy ions, which represents the metal foil itself and a much thinner proton layer, which serves as the contamination layer. The layer is considered thin if it is thinner compared to the skin depth of the accelerating electric field. For a thin proton layer the quasi-static acceleration is the governing mechanism. When the proton layer is larger than skin depth the process can be described as plasma expansion. I found that the energy and phase-space distribution of the protons strongly depends on the layer thickness. In the QSA regime the proton spectrum shows a nearly monoenergetic feature, but the maximum energy is typically low compared to the plasma expansion regime, where the protons have a broad exponential energy spectrum. For the plasma expansion we observe a cut-off energy that logarithmically depends on the acceleration time. The simulation results in these two extreme cases for one- and two-temperature plasmas have been extensively compared to analytical predictions showing an overall good agreement. In the intermediate regime an analytical expression could be obtained for the energy conversion from electrons to protons as a function of electron parameters and layer thickness. By changing the layer thickness a smooth transition between the two extreme cases could be identified. The proton layer thickness also has an

  15. Metal-nanocluster composites made by ion implantation: A novel third-order nonlinear material

    Energy Technology Data Exchange (ETDEWEB)

    Haglund, R.F. Jr.; Yang, L.; Magruder, R.H. III; Becker, K.; Wittig, J.E. [Vanderbilt Univ., Nashville, TN (United States); White, C.W.; Zhur, R.A. [Oak Ridge National Lab., TN (United States); Yang, L.; Dorsinville, R.; Alfano, R.R. [City Univ. of New York, NY (United States)

    1993-03-01

    We describe our recent studies of metal-insulator nanocluster composites made by ion implantation in such substrates as glass and sapphire. The metal clusters have diameters ranging from 3 to 30 nm. The composites exhibit an electronic nonlinear optical response which is fast on the picosecond time scale. In addition to possibilities for technological application, these materials also offer a way of studying unusual properties of composite materials, such as the quantum confinement of conduction-band electrons and the transverse relaxation time T{sub 2} as a function of cluster size.

  16. Metal-nanocluster composites made by ion implantation: A novel third-order nonlinear material

    Energy Technology Data Exchange (ETDEWEB)

    Haglund, R.F. Jr.; Yang, L.; Magruder, R.H. III; Becker, K.; Wittig, J.E. (Vanderbilt Univ., Nashville, TN (United States)); White, C.W.; Zhur, R.A. (Oak Ridge National Lab., TN (United States)); Yang, L.; Dorsinville, R.; Alfano, R.R. (City Univ. of New York, NY (United States))

    1993-03-01

    We describe our recent studies of metal-insulator nanocluster composites made by ion implantation in such substrates as glass and sapphire. The metal clusters have diameters ranging from 3 to 30 nm. The composites exhibit an electronic nonlinear optical response which is fast on the picosecond time scale. In addition to possibilities for technological application, these materials also offer a way of studying unusual properties of composite materials, such as the quantum confinement of conduction-band electrons and the transverse relaxation time T[sub 2] as a function of cluster size.

  17. Flue gas desulfurization/denitrification using metal-chelate additives

    Science.gov (United States)

    Harkness, John B. L.; Doctor, Richard D.; Wingender, Ronald J.

    1986-01-01

    A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

  18. Angular resolved energy analysis of /sup 69/Ga/sup +/ions from a gallium liquid metal ion source

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, P.

    1987-11-01

    An analysis system has been designed and built to characterise liquid metal ion source beams. Both mass and angular resolved energy distribution measurements can be made, from which both FWHM energy spreads and energy deficits can be obtained. This paper briefly describes the system and presents and discusses the first off-axis results taken with a gallium liquid metal ion source.

  19. Headgroup interactions and ion flotation efficiency in mixtures of a chelating surfactant, different foaming agents, and divalent metal ions.

    Science.gov (United States)

    Svanedal, Ida; Boija, Susanne; Norgren, Magnus; Edlund, Håkan

    2014-06-10

    The correlation between interaction parameters and ion flotation efficiency in mixtures of chelating surfactant metal complexes and different foaming agents was investigated. We have recently shown that chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) forms strong coordination complexes with divalent metal ions, and this can be utilized in ion flotation. Interaction parameters for mixed micelles and mixed monolayer formation for Mg(2+) and Ni(2+) complexes with the chelating surfactant 4-C12-DTPA and different foaming agents were calculated by Rubingh's regular solution theory. Parameters for the calculations were extracted from surface tension measurements and NMR diffusometry. The effects of metal ion coordination on the interactions between 4-C12-DTPA and the foaming agents could be linked to a previously established difference in coordination chemistry between the examined metal ions. As can be expected from mixtures of amphoteric surfactants, the interactions were strongly pH-dependent. Strong correlation was found between interaction parameter β(σ) for mixed monolayer formation and the phase-transfer efficiency of Ni(2+) complexes with 4-C12-DTPA during flotation in a customized flotation cell. In a mixture of Cu(2+) and Zn(2+), the significant difference in conditional stability constants (log K) between the metal complexes was utilized to selectively recover the metal complex with the highest log K (Cu(2+)) by ion flotation. Flotation experiments in an excess concentration of metal ions confirmed the coordination of more than one metal ion to the headgroup of 4-C12-DTPA.

  20. Recovery of toxic metal ions from washing effluent containing excess aminopolycarboxylate chelant in solution.

    Science.gov (United States)

    Hasegawa, Hiroshi; Rahman, Ismail M M; Nakano, Masayoshi; Begum, Zinnat A; Egawa, Yuji; Maki, Teruya; Furusho, Yoshiaki; Mizutani, Satoshi

    2011-10-15

    Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatment of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2 mL min(-1). The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants

  1. Metal ion complexation by ionizable crown ethers. Final report, January 1, 1988--June 30, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, R.A.

    1994-12-31

    During the report period a variety of new lipophilic ionizable crown ethers with pendent proton-ionizable groups has been synthesized. The ligands possess one or more ionizable group (carboxylic acid, phosphonic acid monoethyl ester, para-nitrophenol, phosphonic acid) attached to crown ether, monoazacrown ether or diazacrown ether frameworks. These novel chelating agents have either pendent or inward-facing proton-ionizable groups. Such lipophilic proton-ionizable crown ethers are designed for use in multiphase metal ion separations (solvent extraction, liquid membrane transport). In addition a series of proton-ionizable crown ethers without lipophilic groups was prepared to study how structural variations within the ligand influence metal ion complexation in homogeneous media as assessed by NMR spectroscopy or titration calorimetry. A third class of new metal ion-complexing agents is a series of lipophilic acyclic polyether dicarboxylic acids. Competitive solvent extractions of alkali metal and alkaline earth cations and of the mixed species have been conducted to reveal the influence of ring size, nature and attachment site of the lipophilic group, sidearm length, and proton-ionizable group identity and location upon the selectivity and efficiency of metal ion complexation. In addition to such studies of structural variation within the lipophilic proton-ionizable crown ether, the effect of changing the organic solvent and variation of the stripping conditions have been assessed. The influence of structural variations within lipophilic acyclic polyether dicarboxylic acids upon competitive solvent extraction of alkaline earth cations has been probed. Also a new chromogenic, di-ionizable crown ether with extremely high selectivity for Hg{sup 2+} has been discovered.

  2. The electron-transfer based interaction between transition metal ions and photoluminescent graphene quantum dots (GQDs): a platform for metal ion sensing.

    Science.gov (United States)

    Huang, Hongduan; Liao, Lei; Xu, Xiao; Zou, Mingjian; Liu, Feng; Li, Na

    2013-12-15

    The electron-transfer based quenching effect of commonly encountered transition metal ions on the photoluminescence of grapheme quantum dots (GQDs) was for the first time investigated, and was found to be associated with electron configuration of the individual metal ion. Ethylene diamine tetraacetic acid (EDTA), the metal ion chelator, can competitively interact with metal ions to recover the quenched photoluminescence of GQDs. Basically, metal ions with empty or completely filled d orbits could not quench the photoluminescence of GQDs, but this quenching effect was observed for the metal ions with partly filled d orbits. Based on the quenching-recovering strategy, a simple optical metal sensing platform was established by taking Ni(2+) as an example. Using the nickel ion-specific chelating reagent, dimethylglyoxime (DMG), to replace EDTA, a detection limit of 4.1 μM was obtained in standard solution. This proposed strategy does not need further functionalization of GQDs, facilitating the application for simple, fast and cost-effective screening of metal ions.

  3. Quantify the loss of major ions induced by CO2 enrichment and nitrogen addition in subtropical model forest ecosystems

    Science.gov (United States)

    Liu, Juxiu; Zhang, Deqiang; Huang, Wenjuan; Zhou, Guoyi; Li, Yuelin; Liu, Shizhong

    2014-04-01

    Previous studies have reported that atmospheric CO2 enrichment would increase the ion concentrations in the soil water. However, none of these studies could exactly quantify the amount of ion changes in the soil water induced by elevated CO2 and all of these experiments were carried out only in the temperate areas. Using an open-top chamber design, we studied the effects of CO2 enrichment alone and together with nitrogen (N) addition on soil water chemistry in the subtropics. Three years of exposure to an atmospheric CO2 concentration of 700 ppm resulted in accelerated base cation loss via leaching water below the 70 cm soil profile. The total of base cation (K+ + Na+ + Ca2+ + Mg2+) loss in the elevated CO2 treatment was higher than that of the control by 220%, 115%, and 106% in 2006, 2007, and 2008, respectively. The N treatment decreased the effect of high CO2 treatment on the base cation loss in the leachates. Compared to the control, N addition induced greater metal cation (Al3+ and Mn2+) leaching loss in 2008 and net Al3+ and Mn2+ loss in the high N treatment increased by 100% and 67%, respectively. However, the CO2 treatment decreased the effect of high N treatment on the metal cation loss. Changes of ion export followed by the exposure to the elevated CO2, and N treatments were related to both ion concentrations and leached water amount. We hypothesize that forests in subtropical China might suffer from nutrient limitation and some poisonous metal activation in plant biomass under future global change.

  4. Metal ion enhanced binding of AMD3100 to Asp262 in the CXCR4 receptor

    DEFF Research Database (Denmark)

    Gerlach, Lars Ole; Jakobsen, Janus S; Jensen, Kasper P;

    2003-01-01

    +), Zn(2+), or Ni(2+) into the cyclam rings of the compound. The rank order of the transition metal ions correlated with the calculated binding energy between free acetate and the metal ions coordinated in a cyclam ring. Construction of AMD3100 substituted with only a single Cu(2+) or Ni(2+) ion...... demonstrated that the increase in binding affinity of the metal ion substituted bicyclam is achieved through an enhanced interaction of just one of the ring systems. Mutational analysis of potential metal ion binding residues in the main ligand binding crevice of the CXCR4 receptor showed that although binding...... of the bicyclam is dependent on both Asp(171) and Asp(262), the enhancing effect of the metal ion was selectively eliminated by substitution of Asp(262) located at the extracellular end of TM-VI. It is concluded that the increased binding affinity of the metal ion substituted AMD3100 is obtained through enhanced...

  5. Microbial manganese oxide formation and interaction with toxic metal ions.

    Science.gov (United States)

    Miyata, Naoyuki; Tani, Yukinori; Sakata, Masahiro; Iwahori, Keisuke

    2007-07-01

    Diverse bacteria and fungi oxidize Mn(II) enzymatically and produce insoluble Mn(III, IV) oxides, and these organisms are considered to be the primal agents for the occurrence of natural Mn oxide phases in most environments. Biogenic Mn oxides have a high sorption capacity for metal cations and an ability to oxidize numerous inorganic and organic compounds, owing to their structural and redox features. Thus, the microbial process is of significance in both biogeochemical and biotechnological contexts. In this article we summarize the enzymatic Mn(II) oxidation and interactions of biogenic Mn oxides with toxic metal and metalloid ions. Although Mn oxide formation by fungi has not been fully characterized yet, recent researches with ascomycetes emphasize the similarity between the bacterial and fungal Mn(II) oxidation with respect to the involved catalyst (i.e., multicopper oxidase-type enzymes) and the reaction product [i.e., layer-type Mn(IV) oxides]. Laboratory cultures of bacterial and fungal Mn oxidizers are expected to provide fundamental knowledge in their potential use for remediation of environments and effluents contaminated with toxic metal(loid) ions.

  6. The influence of metal ions on malic enzyme activity and lipid synthesis in Aspergillus niger.

    Science.gov (United States)

    Jernejc, Katarina; Legisa, Matic

    2002-12-17

    In the presence of copper significant induction of citric acid overflow was observed, while concomitantly lower levels of total lipids were detected in the cells. Its effect was more obvious in a medium with magnesium as sole divalent metal ions, while in a medium with magnesium and manganese the addition of copper had a less pronounced effect. Since the malic enzyme was recognised as a supplier of reducing power in the form of reduced nicotinamide adenine dinucleotide phosphate for lipid biosynthesis, its kinetic parameters with regard to different concentrations of metal ions were investigated. Some inhibition was found with Fe(2+) and Zn(2+), while Cu(2+) ions in a concentration of 0.1 mM completely abolished malic enzyme activity. The same metal ions proportionally reduced the levels of total lipids in Aspergillus niger cells. A strong competitive inhibition of the enzyme by Cu(2+) was observed. It seemed that copper competes with Mg(2+) and Mn(2+) for the same binding site on the protein.

  7. The Effects of Non—Metal Additives on Hydration Reisitance of MgO—C Bricks

    Institute of Scientific and Technical Information of China (English)

    OUYAGNG; WANGRuikun; 等

    2000-01-01

    The general method of solving the problem of hydration of MgO-C brick is by adding with metal Si,Mg or compround metal additives,but metal additives have bad effect on the MgO-C brick,The test tried adding non-metal additives to matrix material.The results showed that a suitable amount of this kind of additives not only inhibits hydration of MgO-C brick and does not affect corrosion resistance and avoids thermal expansion,but also can improve oxidation resistance.

  8. 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...

  9. The Effect of Complex Formation upon the Redox Potentials of Metallic Ions. Cyclic Voltammetry Experiments.

    Science.gov (United States)

    Ibanez, Jorge G.; And Others

    1988-01-01

    Describes experiments in which students prepare in situ soluble complexes of metal ions with different ligands and observe and estimate the change in formal potential that the ion undergoes upon complexation. Discusses student formation and analysis of soluble complexes of two different metal ions with the same ligand. (CW)

  10. Hydration number of alkali metal ions determined by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2008-01-01

    . 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...

  11. The Effect of Complex Formation upon the Redox Potentials of Metallic Ions. Cyclic Voltammetry Experiments.

    Science.gov (United States)

    Ibanez, Jorge G.; And Others

    1988-01-01

    Describes experiments in which students prepare in situ soluble complexes of metal ions with different ligands and observe and estimate the change in formal potential that the ion undergoes upon complexation. Discusses student formation and analysis of soluble complexes of two different metal ions with the same ligand. (CW)

  12. Stability of Conductive Carbon Additives for High-voltage Li-ion Battery Cathodes

    OpenAIRE

    Nilssen, Benedicte Eikeland

    2014-01-01

    Conductive carbon additives are important constituents of the current state-of-the-art Li-ion battery cathodes, as the traditional active cathode materials are characterized by too low electronic conductivities. In high-voltage Li-ion batteries, these additives are subject for anion intercalation and electrolyte oxidation, which might cause changes in the conductive carbon network in the cathode, and hence the overall cycling performance of the electrode. This thesis has focused on study the ...

  13. Lanthanide metal-organic frameworks as selective microporous materials for adsorption of heavy metal ions.

    Science.gov (United States)

    Jamali, Abbas; Tehrani, Alireza Azhdari; Shemirani, Farzaneh; Morsali, Ali

    2016-06-14

    Four microporous lanthanide metal-organic frameworks (MOFs), namely Ln(BTC)(H2O)(DMF)1.1 (Ln = Tb, Dy, Er and Yb, DMF = dimethylformamide, H3BTC = benzene-1,3,5-tricarboxylic acid), have been used for selective adsorption of Pb(ii) and Cu(ii). Among these MOFs, the Dy-based MOF shows better adsorption property and selectivity toward Pb(ii) and Cu(ii) ions. Adsorption isotherms indicate that sorption of Pb(ii) and Cu(ii) on MOFs is via monolayer coverage. Preconcentration is based on solid-phase extraction in which MOFs were rapidly injected into water samples and adsorption of metal ions was rapid because of good contact with analyte; then adsorbed Pb(ii) and Cu(ii) ions were analyzed by FAAS. The optimized methodology represents good linearity between 1 and 120 μg L(-1) and detection limit of 0.4 and 0.26 μg L(-1) for Pb(ii) and Cu(ii), respectively. Subsequently the method was evaluated for preconcentration of target metal ions in some environmental water samples.

  14. Phenomenological understanding of dewetting and embedding of noble metal nanoparticles in thin films induced by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Jai, E-mail: jai.gupta1983@gmail.com [Department of Chemistry, MMH College (Ch. Charan Singh University Meerut), Ghaiziabad 201001 (India); Chemical Physics of Materials, Université Libre de Bruxelles, Campus de la Plaine, CP 243, B-1050 Bruxelles (Belgium); Tripathi, A. [Inter University Accelerator Centre, Aruna Asif Ali Marg, New Delhi 110067 (India); Gautam, Sanjeev; Chae, K.H.; Song, Jonghan [Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136–791 (Korea, Republic of); Rigato, V. [INFN Laboratori Nazionali di Legnaro, Via Romea. 4, 35020 Legnaro, Padova (Italy); Tripathi, Jalaj [Department of Chemistry, MMH College (Ch. Charan Singh University Meerut), Ghaiziabad 201001 (India); Asokan, K. [Inter University Accelerator Centre, Aruna Asif Ali Marg, New Delhi 110067 (India)

    2014-10-15

    The present experimental work provides the phenomenological approach to understand the dewetting in thin noble metal films with subsequent formation of nanoparticles (NPs) and embedding of NPs induced by ion irradiation. Au/polyethyleneterepthlate (PET) bilayers were irradiated with 150 keV Ar ions at varying fluences and were studied using scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (X-TEM). Thin Au film begins to dewet from the substrate after irradiation and subsequent irradiation results in spherical nanoparticles on the surface that at a fluence of 5 × 10{sup 16} ions/cm{sup 2} become embedded into the substrate. In addition to dewetting in thin films, synthesis and embedding of metal NPs by ion irradiation, the present article explores fundamental thermodynamic principles that govern these events systematically under the effect of irradiation. The results are explained on the basis of ion induced sputtering, thermal spike inducing local melting and of thermodynamic driving forces by minimization of the system free energy where contributions of surface and interfacial energies are considered with subsequent ion induced viscous flow in substrate. - Highlights: • Phenomenological interpretation of dewetting and embedding of metal NPs in thin film. • Exploring fundamental thermodynamic principles under influence of ion irradiation. • Ion induced surface/interface microstructural changes using SEM/X-TEM. • Ion induced sputtering, thermal spike induced local melting. • Thermodynamic driving forces relate to surface and interfacial energies.

  15. The use of Electrolyte Additives to Improve the High Temperature Resilience of Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall C.; Lucht, B. L.; Ratnakumar, Bugga V.

    2007-01-01

    This viewgraph presentation reviews the use of electrolyte additves to improve the resillience of Lithium ion cells. The objective of this work is to identify lithium-ion electrolytes, which will lead to Li-ion cells with a wide operational temperature range (+60 to -60 C), and to develop Li-ion electrolytes which result in cells that display improved high temperature resilience. Significant improvement in the high temperature resilience of Li-ion cells containing these additives was observed, with the most dramatic benefit being displayed by addition of DMAc. When the electrochemical properties of the individual electrodes were analyzed, the degradation of the anode kinetics was slowed most dramatically by the incorporation of DMAc into the electrolytes. Whereas, the greatest retention in the cathode kinetics was observed in the cell containing the electrolyte with VC added.

  16. Ultrasonic Additive Manufacturing for Lightweight Metallic Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this program is to demonstrate the use of UAM to additively build reinforcement structures to reinforce cut outs in larger aluminum structural...

  17. Alloying of metal nanoparticles by ion-beam induced sputtering

    Science.gov (United States)

    Magudapathy, P.; Srivastava, S. K.; Gangopadhyay, P.; Amirthapandian, S.; Saravanan, K.; Das, A.; Panigrahi, B. K.

    2017-01-01

    Ion-beam sputtering technique has been utilized for controlled synthesis of metal alloy nanoparticles of compositions that can be tuned. Analysis of various experimental results reveals the formation of Ag-Cu alloy nanoparticles on a silica substrate. Surface-plasmon optical resonance positions and observed shifts of Ag Bragg angles in X-ray diffraction pattern particularly confirm formation of alloy nanoparticles on glass samples. Sputtering induced nano-alloying mechanism has been discussed and compared with thermal mixing of Ag and Cu thin films on glass substrates. Compositions and sizes of alloy nanoparticles formed during ion-beam induced sputtering are found to exceed far from the values of thermal mixing.

  18. Metal-organic frameworks for lithium ion batteries and supercapacitors

    Science.gov (United States)

    Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang

    2015-03-01

    Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100-1000 m2 g-1) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m2 g-1), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs.

  19. Metal-organic frameworks for lithium ion batteries and supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Fu-Sheng; Wu, Yu-Shan; Deng, Hexiang, E-mail: hdeng@whu.edu.cn

    2015-03-15

    Porous materials have been widely used in batteries and supercapacitors attribute to their large internal surface area (usually 100–1000 m{sup 2} g{sup −1}) and porosity that can favor the electrochemical reaction, interfacial charge transport, and provide short diffusion paths for ions. As a new type of porous crystalline materials, metal-organic frameworks (MOFs) have received huge attention in the past decade due to their unique properties, i.e. huge surface area (up to 7000 m{sup 2} g{sup −1}), high porosity, low density, controllable structure and tunable pore size. A wide range of applications including gas separation, storage, catalysis, and drug delivery benefit from the recent fast development of MOFs. However, their potential in electrochemical energy storage has not been fully revealed. Herein, the present mini review appraises recent and significant development of MOFs and MOF-derived materials for rechargeable lithium ion batteries and supercapacitors, to give a glimpse into these potential applications of MOFs. - Graphical abstract: MOFs with large surface area and high porosity can offer more reaction sites and charge carriers diffusion path. Thus MOFs are used as cathode, anode, electrolyte, matrix and precursor materials for lithium ion battery, and also as electrode and precursor materials for supercapacitors. - Highlights: • MOFs have potential in electrochemical area due to their high porosity and diversity. • We summarized and compared works on MOFs for lithium ion battery and supercapacitor. • We pointed out critical challenges and provided possible solutions for future study.

  20. Clusters distributions on charges and dimensions at ion metal sputtering

    CERN Document Server

    Matveev, V I

    2001-01-01

    The theory on the metal sputtering in form of large (with the atoms number N >= 5) neutral and charged clusters under the impact of the ion bombardment is considered. The probability of the cluster emission, consisting of the N atoms, is calculated on the basis of the Einstein model. The charge state of the cluster, consisting of the N atoms, is determined. The obtained formulae agree well with the experimental results. It is noted, that the mass-spectra of the neutral clusters slightly depend on the target temperature, whereas the mass-spectra of the single charge clusters essentially depend on the target temperature

  1. 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......-terminus. CueR has a high selectivity for Cu+, Ag+ and Au+, but exhibits no transcriptional activity for the divalent ions Hg2+ and Zn2+.2 The two Cys- residues of the metal binding loop were shown to settle M+ ions into a linear coordination environment but other factors may also play a role in the recognition...... 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....

  2. 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.

  3. Supplementation of soft drinks with metallic ions reduces dissolution of bovine enamel

    Science.gov (United States)

    PEREIRA, Heloisa Aparecida Barbosa da Silva; LEITE, Aline de Lima; ITALIANI, Flávia de Moraes; KATO, Melissa Thiemi; PESSAN, Juliano Pelim; BUZALAF, Marília Afonso Rabelo

    2013-01-01

    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. PMID:24037077

  4. Acetabular bone density and metal ions after metal-on-metal versus metal-on-polyethylene total hip arthroplasty; short-term results

    NARCIS (Netherlands)

    Zijlstra, Wierd P.; van der Veen, Hugo C.; van den Akker-Scheek, Inge; Zee, Mark J. M.; Bulstra, Sjoerd K.; van Raay, Jos J. A. M.

    2014-01-01

    Information on periprosthetic acetabular bone density is lacking for metal-on-metal total hip arthroplasties. These bearings use cobalt-chromium instead of titanium acetabular components, which could lead to stress shielding and hence periprosthetic bone loss. Cobalt and chromium ions have detriment

  5. Effect of metal ions on some pharmacologically relevant interactions involving fluoroquinolone antibiotics.

    Science.gov (United States)

    Seedher, Neelam; Agarwal, Pooja

    2010-01-01

    Complexation of five metal cations, Fe(3+), Al(3+), Zn(2+), Cu(2+) and Mg(2+) with four fluoroquinolones, levofloxacin, sparfloxacin, ciprofloxacin hydrochloride and enrofloxacin and human serum albumin (HSA) has been studied for better understanding of bioavailability of drugs interacting with metals and proteins. The binding parameters have been determined using fluorescence and ultraviolet absorption spectroscopic techniques. The effect of metal cations on the interaction of fluoroquinolones with HSA has also been investigated. The association constants were of the order of 10(2)-10(4) for the fluoroquinolone-metal ion interaction. For a given drug, the chelation potential of Al(3+) was highest, whereas that of Mg(2+) was lowest. At a metal ion/drug ratio of 1:1, approximately 50%-73% of metal ion was bound per mole drug in most cases. In the case of HSA-metal ion interaction, for Fe(3+) and Zn(2+) ions, there was only one class of binding site, whereas for Al(3+) and Cu(2+) ions, two types of binding sites were found. The relative affinity of various metal ions was found to vary as Al(3+)>Cu(2+)>Zn(2+)>Fe(3+). The extent of binding was found to be independent of the charge on the ion. Owing to very weak quenching of fluorescence, the association constant for the interaction of Mg(2+) ion could not be determined by this technique. The binding affinity of all the fluoroquinolones to HSA was found to increase in the presence of Cu(2+) ions, whereas all other metal ions decreased the binding -affinity with the exception of levofloxacin in the presence of Zn(2+) and Al(3+) ions. Increase in the binding affinity indicated that the metal ions facilitate HSA-fluoroquinolone interaction and fluoroquinolones probably interact with HSA via a metal ion bridge. Decrease in the binding affinity, by contrast, can either be due to the fact that fluoroquinolone-metal ion complex inhibits fluoroquinolone-HSA interaction or metal ions produce conformational changes in the HSA

  6. Preorganized and Immobilized Ligands for Metal Ion Separations

    Energy Technology Data Exchange (ETDEWEB)

    Paine, Robert T. [Univ. of New Mexico, Albuquerque, NM (United States)

    2015-07-01

    The research project, in the period 2003-2015, was focused on the discovery of fundamental new principles in f-element ion coordination chemistry and the application of the new knowledge to the development of advanced detection/separations reagents and methods for these ions. The findings relate to the Nation's efforts to safely and efficiently process nuclear materials. In addition, the project provided training for young scientists needed to maintain the Nation's preeminence in nuclear science.

  7. The Coupled Photothermal Reaction and Transport in a Laser Additive Metal Nanolayer Simultaneous Synthesis and Pattering for Flexible Electronics

    Directory of Open Access Journals (Sweden)

    Song-Ling Tsai

    2016-01-01

    Full Text Available The Laser Direct Synthesis and Patterning (LDSP technology has advantages in terms of processing time and cost compared to nanomaterials-based laser additive microfabrication processes. In LDSP, a scanning laser on the substrate surface induces chemical reactions in the reactive liquid solution and selectively deposits target material in a preselected pattern on the substrate. In this study, we experimentally investigated the effect of the processing parameters and type and concentration of the additive solvent on the properties and growth rate of the resulting metal film fabricated by this LDSP technology. It was shown that reactive metal ion solutions with substantial viscosity yield metal films with superior physical properties. A numerical analysis was also carried out the first time to investigate the coupled opto-thermo-fluidic transport phenomena and the effects on the metal film growth rate. To complete the simulation, the optical properties of the LDSP deposited metal film with a variety of thicknesses were measured. The characteristics of the temperature field and the thermally induced flow associated with the moving heat source are discussed. It was shown that the processing temperature range of the LDSP is from 330 to 390 K. A semi-empirical model for estimating the metal film growth rate using this process was developed based on these results. From the experimental and numerical results, it is seen that, owing to the increased reflectivity of the silver film as its thickness increases, the growth rate decreases gradually from about 40 nm at initial to 10 nm per laser scan after ten scans. This self-controlling effect of LDSP process controls the thickness and improves the uniformity of the fabricated metal film. The growth rate and resulting thickness of the metal film can also be regulated by adjustment of the processing parameters, and thus can be utilized for controllable additive nano/microfabrication.

  8. Amperometric detection of heavy metal ions in ion pair chromatography at an array of water/nitrobenzene micro interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wilke, S. [Martin-Luther-Univ. Halle-Wittenberg, Merseburg (Germany). Fachbereich Chemie; Wang, H. [Martin-Luther-Univ. Halle-Wittenberg, Merseburg (Germany). Fachbereich Chemie; Muraczewska, M. [Martin-Luther-Univ. Halle-Wittenberg, Merseburg (Germany). Fachbereich Chemie; Mueller, H. [Martin-Luther-Univ. Halle-Wittenberg, Merseburg (Germany). Fachbereich Chemie

    1996-10-01

    A novel amperometric detector for heavy metal ions has been developed and successfully applied for ion pair chromatography. The detector is based on the electrochemical transfer of the metal ions across an array of water/nitrobenzene micro interfaces. The ion transfer is facilitated by the neutral ionophores methylenebis(diphenylphosphineoxide) and methylenebis(di- phenylphosphinesulfide). More than eight metals are separated in less than 15 min on an RP18 column using octyl sulfonate as ion pair reagent. For the heavy metals, the limits of decision are 19(Pb{sup 2+}), 9(Zn{sup 2+}), 9l (Co{sup 2+}), 8(Cd{sup 2+}) and 1.6(Mn{sup 2+}) {mu}g/L. The applicability of the new method for water samples is demonstrated. (orig.). With 3 figs., 2 tabs.

  9. Part height control of laser metal additive manufacturing process

    Science.gov (United States)

    Pan, Yu-Herng

    Laser Metal Deposition (LMD) has been used to not only make but also repair damaged parts in a layer-by-layer fashion. Parts made in this manner may produce less waste than those made through conventional machining processes. However, a common issue of LMD involves controlling the deposition's layer thickness. Accuracy is important, and as it increases, both the time required to produce the part and the material wasted during the material removal process (e.g., milling, lathe) decrease. The deposition rate is affected by multiple parameters, such as the powder feed rate, laser input power, axis feed rate, material type, and part design, the values of each of which may change during the LMD process. Using a mathematical model to build a generic equation that predicts the deposition's layer thickness is difficult due to these complex parameters. In this thesis, we propose a simple method that utilizes a single device. This device uses a pyrometer to monitor the current build height, thereby allowing the layer thickness to be controlled during the LMD process. This method also helps the LMD system to build parts even with complex parameters and to increase material efficiency.

  10. 3D metal droplet printing development and advanced materials additive manufacturing

    Directory of Open Access Journals (Sweden)

    Lawrence E. Murr

    2017-01-01

    Full Text Available While commercial additive manufacturing processes involving direct metal wire or powder deposition along with powder bed fusion technologies using laser and electron beam melting have proliferated over the past decade, inkjet printing using molten metal droplets for direct, 3D printing has been elusive. In this paper we review the more than three decades of development of metal droplet generation for precision additive manufacturing applications utilizing advanced, high-temperature metals and alloys. Issues concerning process optimization, including product structure and properties affected by oxidation are discussed and some comparisons of related additive manufactured microstructures are presented.

  11. Overview of Materials Qualification Needs for Metal Additive Manufacturing

    Science.gov (United States)

    Seifi, Mohsen; Salem, Ayman; Beuth, Jack; Harrysson, Ola; Lewandowski, John J.

    2016-03-01

    This overview highlights some of the key aspects regarding materials qualification needs across the additive manufacturing (AM) spectrum. AM technology has experienced considerable publicity and growth in the past few years with many successful insertions for non-mission-critical applications. However, to meet the full potential that AM has to offer, especially for flight-critical components (e.g., rotating parts, fracture-critical parts, etc.), qualification and certification efforts are necessary. While development of qualification standards will address some of these needs, this overview outlines some of the other key areas that will need to be considered in the qualification path, including various process-, microstructure-, and fracture-modeling activities in addition to integrating these with lifing activities targeting specific components. Ongoing work in the Advanced Manufacturing and Mechanical Reliability Center at Case Western Reserve University is focusing on fracture and fatigue testing to rapidly assess critical mechanical properties of some titanium alloys before and after post-processing, in addition to conducting nondestructive testing/evaluation using micro-computerized tomography at General Electric. Process mapping studies are being conducted at Carnegie Mellon University while large area microstructure characterization and informatics (EBSD and BSE) analyses are being conducted at Materials Resources LLC to enable future integration of these efforts via an Integrated Computational Materials Engineering approach to AM. Possible future pathways for materials qualification are provided.

  12. Most spin-1/2 transition-metal ions do have single ion anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jia; Whangbo, Myung-Hwan, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695 (United States); Koo, Hyun-Joo [Department of Chemistry and Research Institute for Basic Sciences, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Xiang, Hongjun, E-mail: hxiang@fudan.edu.cn, E-mail: mike-whangbo@ncsu.edu [Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433 (China); Kremer, Reinhard K. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2014-09-28

    The cause for the preferred spin orientation in magnetic systems containing spin-1/2 transition-metal ions was explored by studying the origin of the easy-plane anisotropy of the spin-1/2 Cu{sup 2+} ions in CuCl{sub 2}·2H{sub 2}O, LiCuVO{sub 4}, CuCl{sub 2}, and CuBr{sub 2} on the basis of density functional theory and magnetic dipole-dipole energy calculations as well as a perturbation theory treatment of the spin-orbit coupling. We find that the spin orientation observed for these spin-1/2 ions is not caused by their anisotropic spin exchange interactions, nor by their magnetic dipole-dipole interactions, but by the spin-orbit coupling associated with their crystal-field split d-states. Our study also predicts in-plane anisotropy for the Cu{sup 2+} ions of Bi{sub 2}CuO{sub 4} and Li{sub 2}CuO{sub 2}. The results of our investigations dispel the mistaken belief that magnetic systems with spin-1/2 ions have no magnetic anisotropy induced by spin-orbit coupling.

  13. Metal ion binding with dehydroannulenes - Plausible two-dimensional molecular sieves

    Indian Academy of Sciences (India)

    B Sateesh; Y Soujanya; G Narahari Sastry

    2007-09-01

    Theoretical investigations have been carried out at B3LYP/6-311++G∗∗ level of theory to study the binding interaction of various metal ions, Li+, Na+ and K+ with dehydroannulene systems. The present study reveals that alkali metal ions bind strongly to dehydroannulenes and the passage through the central cavity is controlled by the size of metal ion and dimension of dehydroannulene cavity.

  14. Triboelectrification-Enabled Self-Powered Detection and Removal of Heavy Metal Ions in Wastewater.

    Science.gov (United States)

    Li, Zhaoling; Chen, Jun; Guo, Hengyu; Fan, Xing; Wen, Zhen; Yeh, Min-Hsin; Yu, Chongwen; Cao, Xia; Wang, Zhong Lin

    2016-04-20

    A fundamentally new working principle into the field of self-powered heavy-metal-ion detection and removal using the triboelectrification effect is introduced. The as-developed tribo-nanosensors can selectively detect common heavy metal ions. The water-driven triboelectric nanogenerator is taken as a sustainable power source for heavy-metal-ion removal by recycling the kinetic energy from flowing wastewater.

  15. Liquid-liquid extraction of metal ions by the 6-membered N-containing macrocycle hexacyclen.

    Science.gov (United States)

    Arpadjan, S; Mitewa, M; Bontchev, P R

    1987-11-01

    The nitrogen-containing analogue of 18-crown-6, 1,4,7,10,13,16-hexa-azaoctadecane (hexacyclen)] was studied as a reagent for complexation and extraction of some metal ions. It was found that with this reagent and methyl isobutyl ketone, metal ions such as silver(I), mercury(II), copper(II), platinum(II) and palladium(II) can be quantitatively extracted and separated from iron(III) and some other metal ions.

  16. The reactivity study of peptide A3-capped gold and silver nanoparticles with heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hongyu [New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Tang, Zhenghua, E-mail: zhht@scut.edu.cn [New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Wang, Likai; Zhou, Weijia; Li, Ligui [New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Zhang, Yongqing [Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Chen, Shaowei, E-mail: shaowei@ucsc.edu [New Energy Research Institute, School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2016-08-15

    Highlights: • Apparent color change upon the addition of Hg{sup 2+} or As{sup 3+} ions into A3-AuNPs solution. • Distinct color change of A3-AgNPs solution only in the presence of Hg{sup 2+} ions. • The Hg{sup 2+} concentration limit of A3-AgNPs about 40 times lower than A3-AuNPs. • Based on the DLS, TEM and XPS results, two reaction mechanisms have been proposed. - Abstract: Peptide A3-capped gold and silver nanoparticles were prepared by chemical reduction of metal salt precursors. The nanoparticles exhibited apparent but distinctly different color changes upon the addition of selected heavy metal ions. For gold nanoparticles, the solution color was found to change from red to blue in the presence of Hg{sup 2+} or As{sup 3+} ions, accompanied with broadening and a red-shift of the surface plasmon resonance peak. In contrast, silver nanoparticles showed an apparent color change from yellow to colorless only in the presence of Hg{sup 2+}, along with a blue-shift and diminishment of the surface plasmon resonance peak. The Hg{sup 2+} reaction concentration limit of silver nanoparticle was about 40 times lower than that of gold nanoparticle. Based on the dynamic light scattering, transmission electron microscopy and X-ray photoelectron spectroscopic results, the reaction mechanism has been proposed. Such a sensitive variation of the nanoparticle optical properties to selective ions might be exploited for ion detection for potential applications.

  17. 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.

  18. Metal ion sorption by untreated and chemically treated biomass

    Energy Technology Data Exchange (ETDEWEB)

    Kilbane, J.J.; Xie, J.

    1992-12-31

    The metal-binding ability of biosorbents is well known; however, in comparison with commercial ion-exchange resins the capacity of biosorbents is low. The purpose of this research was to examine chemically modified biosorbents and biosorbents prepared from microorganisms isolated from extreme environments to determine if significant improvements in metal-binding capacity or biosorbents with unique capabilities could be produced. Chemical treatments examined included acid, alkali, carbon disulfide, phosphorus oxychloride, anhydrous formamide, sodium thiosulfate, sodium chloroacetic acid, and phenylsulfonate. Biosorbents were prepared from microorganisms isolated from pristine and acid mine drainage impacted sites and included heterotrophs, methanotrophs, algae, and sulfate reducers. Chemical modification with carbon disulfide, phosphorous oxychloride, and sodium thiosulfate yielded biosorbents with such as much as 74%, 133%, and 155% improvements, respectively, in metal-binding capacity, but the performance of these chemically modified biosorbents deteriorated upon repeated use. A culture isolated from an acid mine drainage impacted site, IGTM17, exhibits about 3-fold higher metal-binding capacity in comparison with other biosorbents examined in this study. IGTM17 also exhibits superior metal-binding ability at decreased pH or in the presence of interfering common cations in comparison with other biosorbents or some commercially available cation exchange resins. Some biosorbents, such as IGTM5, can bind anions. To our knowledge this is the first demonstration of the ability of biosorbents to bind anions. Moreover, preliminary data indicate that the chemical modification of biosorbents may be capable of imparting the ability to selectively bind certain anions. Further research is needed to optimize conditions for the chemical modification and stabilization of biosorbents.

  19. Properties of Hydrated Alkali Metals Aimed at the Ion Channel Selectivity

    Institute of Scientific and Technical Information of China (English)

    AN Hai-Long; LIU Yu-Zhi; ZHANG Su-Hua; ZHAN Yong; ZHANG Hai-Lin

    2008-01-01

    The hydration structure properties of different alkali metal ions with eight water molecules and potassium ions with different numbers of water molecules are studied using the mixed density functional theory, B3LYP, with 6-311G basis set. The hydration structures are obtained from structure optimization and the optimum numbers of water molecules in the innermost hydration shell for the alkali metal ions are found. Some useful information about the ion channel selectivity is presented.

  20. Fe-based bulk metallic glasses with Y addition

    Energy Technology Data Exchange (ETDEWEB)

    Baser, Tanya Aycan [Dipartimento di Chimica IFM and NIS, Universita di Torino, Via P.Giuria, 9-10125 Torino (Italy); Baricco, Marcello [Dipartimento di Chimica IFM and NIS, Universita di Torino, Via P.Giuria, 9-10125 Torino (Italy)]. E-mail: marcello.baricco@unito.it

    2007-05-31

    This paper aims to study the role of residual vacuum during sample preparation and of quenching rate on glass formation in Fe{sub 50-x}Cr{sub 15}Mo{sub 14}Y {sub x}C{sub 15}B{sub 6} (x = 0, 2) alloys. The equilibrium phase mixture has been clarified for both alloys, combining X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements. The beneficial effects of minor addition of Y on the glass formation are evidenced. A high residual vacuum during sample preparation promotes glass formation. Glass transition temperature for amorphous sample containing 2 at.% Y is 881 K and the onset crystallization temperature is 904 K. The melting behavior for both as-cast alloys were measured with high temperature differential scanning calorimeter (HTDSC). Melting starts at 1384 K, ends at 1506 and 1470 K as liquidus temperatures for Fe{sub 50}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6} and Fe{sub 48}Cr{sub 15}Mo{sub 14}Y{sub 2}C{sub 15}B{sub 6} alloys, respectively. The addition of Y leads to a melting behavior of as-cast sample close to eutectic, which enhances glass formation.

  1. Nanoparticles reduce nickel allergy by capturing metal ions

    Science.gov (United States)

    Vemula, Praveen Kumar; Anderson, R. Rox; Karp, Jeffrey M.

    2011-05-01

    Approximately 10% of the population in the USA suffer from nickel allergy, and many are unable to wear jewellery or handle coins and other objects that contain nickel. Many agents have been developed to reduce the penetration of nickel through skin, but few formulations are safe and effective. Here, we show that applying a thin layer of glycerine emollient containing nanoparticles of either calcium carbonate or calcium phosphate on an isolated piece of pig skin (in vitro) and on the skin of mice (in vivo) prevents the penetration of nickel ions into the skin. The nanoparticles capture nickel ions by cation exchange, and remain on the surface of the skin, allowing them to be removed by simple washing with water. Approximately 11-fold fewer nanoparticles by mass are required to achieve the same efficacy as the chelating agent ethylenediamine tetraacetic acid. Using nanoparticles with diameters smaller than 500 nm in topical creams may be an effective way to limit the exposure to metal ions that can cause skin irritation.

  2. 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.

  3. 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, Michael A.; Kajdacsy-Balla, A.

    2011-01-01

    BACKGROUND There 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. METHODS We 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. RESULTS Patients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 ??g/g vs. 111 ??g/g; P = 0.04) and 21% lower zinc (279 ??g/g vs. 346 ??g/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 ??g/g vs. 0.439 ??g/g; 4% higher) and selenium (1.68 ??g/g vs. 1.58 ??g/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively). CONCLUSIONS There 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. Copyright ?? 2011 Wiley-Liss, Inc.

  4. Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity.

    Science.gov (United States)

    Devi, Jai; Batra, Nisha; Malhotra, Rajesh

    2012-11-01

    New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL(1) and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL(2) derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML((1-2)2) have been synthesized, where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mnantibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu>Mn>Ni>Co>Zn.

  5. Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity

    Science.gov (United States)

    Devi, Jai; Batra, Nisha; Malhotra, Rajesh

    2012-11-01

    New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL1 and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL2 derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML(1-2)2 have been synthesized, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate ? coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu > Mn > Ni > Co > Zn.

  6. Adhesion and interfacial characteristics of metal/PI composite film modified by O{sub 2} ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.J. [Advanced Functional Materials Research Center, Korea Institute of Science and Technology, 39-1 Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of); Kim, Yoon B. [Advanced Functional Materials Research Center, Korea Institute of Science and Technology, 39-1 Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of)], E-mail: ybkim@kist.re.kr

    2008-12-01

    In this study, the adhesion and interface characteristics of NiCr/Cu metal film on PI film modified by O{sub 2} ion beam were investigated. The surface modification of PI film by O{sub 2} ion beam enabled a significant decrease of contact angles of water from 68 deg. to 4.4 deg. at an ion dose of 1 x 10{sup 18} ions/cm{sup 2}, which resulted in an increase of surface energy by a factor of two. The XPS (X-ray Photoelectron Spectroscopy) spectrum showed that the functional groups of C-O and C=O bonding on PI surface were increased by the interaction between scissored unstable chains and reactive ions. The peel strength between PI and NiCr/Cu metal film increased with an increase of ion dose and the highest peel strength of 0.70 N/mm was obtained at an ion dose of 1 x 10{sup 18} ions/cm{sup 2}. According to the XPS depth profile from NiCr metal layer into modified PI film, the O1s peak was broadened at near-interface region with an increase of depth from NiCr layer, which indicates that the new chemical bonding state was formed. In addition to C-O and C=O bonding, the newly formed chemical bonding at the interface between NiCr metal film and PI film was identified as metal-oxide compounds such as NiO, Cr{sub 2}O{sub 3}, and Cr-O by XPS curve fitting. Consequently, the improvement of adhesion is primarily attributed to the strong chemical bonding caused by the chemical interaction between NiCr and newly formed functional group by O{sub 2} ion beam.

  7. Polydopamine-mediated surface-functionalization of graphene oxide for heavy metal ions removal

    Science.gov (United States)

    Dong, Zhihui; Zhang, Feng; Wang, Dong; Liu, Xia; Jin, Jian

    2015-04-01

    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 Cu2+, Cd2+, Pb2+, Hg2+ 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 m2/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 Cu2+, Cd2+, Pb2+, and Hg2+, respectively), it could be recycled several times in a simple way by releasing adsorbed metal ions, indicating its potential application for cleaning wastewater.

  8. Metal ion and inter-domain interactions as functional networks in E. coli topoisomerase I.

    Science.gov (United States)

    Sissi, Claudia; Cheng, Bokun; Lombardo, Valentina; Tse-Dinh, Yuk-Ching; Palumbo, Manlio

    2013-07-25

    Escherichia coli topoisomerase I (EcTopoI) is a type IA bacterial topoisomerase which is receiving large attention due to its potential application as novel target for antibacterial therapeutics. Nevertheless, a detailed knowledge of its mechanism of action at molecular level is to some extent lacking. This is partly due to the requirement of several factors (metal ions, nucleic acid) to the proper progress of the enzyme catalytic cycle. Additionally, each of them can differently affect the protein structure. Here we assess the role of the different components (DNA, metal ions, protein domains) in a dynamic environment as in solution by monitoring the catalytic as well as the structural properties of EcTopoI. Our results clearly indicated the interaction among these components as functionally relevant and underlined their mutual involvement. Some similarities with other enzymes of the same family emerged (for example DNA prevents divalent metal ions coordination at non selective binding sites). Interestingly, same interactions (C- and N-terminal domain interaction) appear to be peculiar of this bacterial topoisomerase which suggest they could be favorably exploited to the design of selective inhibitors for this class of enzyme.

  9. Rice straw modified by click reaction for selective extraction of noble metal ions.

    Science.gov (United States)

    Wang, Jingjing; Wei, Jun; Li, Juan

    2015-02-01

    Rice straw was modified by azide-alkyne click reaction in order to realize selective extraction of noble metal ions. The ability of the modified straw to adsorb Pd(2+) and Pt(4+) was assessed using a batch adsorption technique. It was found that the sorption equilibrium could be reached within 1h and the adsorption capacity increased with temperature for both Pd(2+) and Pt(4+). The maximum sorption capacities for Pd(2+) and Pt(4+) were respectively attained in 1.0 and 0.1 mol/L HCl. The modified straw showed excellent selectivity for noble metal ions in comparison to the pristine straw. In addition, the modified straw was examined as a column packing material for extraction of noble metal ions. It was indicated that 1.0 mL/min was the best flow rate for Pd(2+) and Pt(4+). The modified straw could be repeatedly used for 10 times without any significant loss in the initial binding affinity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Photodetachment microscopy of a hydrogen negative ion in an electric field near a metal surface

    Institute of Scientific and Technical Information of China (English)

    Tang Tian-Tian; Wang De-Hua; Wang Shan-Shan

    2012-01-01

    According to the semi-classical theory,we study the photodetachment microscopy of H- in the electric field near a metal surface.During the photodetachment,the electron is photo-detached by a laser and the electron is drawn toward a position-sensitive detector.The electron flux distribution is measured as a function of position.Two classical paths lead the ion to any point in the classically allowed region on the detector,and waves traveling along these paths produce an interference pattern.If the metal surface perpendicular to the electric field is added,we find that the interference pattern is related not only to the electron energy and the electric-field strength,but also to the ion-surface distance.In addition,the laser polarization also has a great influence on the electron flux distribution.We present calculations predicting the interference pattern that may be seen in experiment.We hope that our study can provide a new nnderstanding of the electron flux distribution of negative ions in an external field and surface,and can guide future experimental research on negative ion photo-detachment microscopy.

  11. Strategy for Texture Management in Metals Additive Manufacturing

    Science.gov (United States)

    Kirka, M. M.; Lee, Y.; Greeley, D. A.; Okello, A.; Goin, M. J.; Pearce, M. T.; Dehoff, R. R.

    2017-03-01

    Additive manufacturing (AM) technologies have long been recognized for their ability to fabricate complex geometric components directly from models conceptualized through computers, allowing for complicated designs and assemblies to be fabricated at lower costs, with shorter time to market, and improved function. Lacking behind the design complexity aspect is the ability to fully exploit AM processes for control over texture within AM components. Currently, standard heat-fill strategies utilized in AM processes result in largely columnar grain structures. Proposed in this work is a point heat source fill for the electron beam melting (EBM) process through which the texture in AM materials can be controlled. Through this point heat source strategy, the ability to form either columnar or equiaxed grain structures upon solidification through changes in the process parameters associated with the point heat source fill is demonstrated for the nickel-base superalloy, Inconel 718. Mechanically, the material is demonstrated to exhibit either anisotropic properties for the columnar-grained material fabricated through using the standard raster scan of the EBM process or isotropic properties for the equiaxed material fabricated using the point heat source fill.

  12. Transition Metal Ions at the Crossroads of Mucosal Immunity and Microbial Pathogenesis

    Directory of Open Access Journals (Sweden)

    Vladimir eDiaz-Ochoa

    2014-01-01

    Full Text Available Transition metal ions are essential micronutrients for all living organisms. In mammals, these ions are often protein-bound and sequestered within cells, limiting their availability to microbes. Moreover, in response to infection, mammalian hosts further reduce the availability of metal nutrients by activating epithelial cells and recruiting neutrophils, both of which release metal-binding proteins with antimicrobial function. Microorganisms, in turn, have evolved sophisticated systems to overcome these limitations and acquire the metal ions essential for their growth. Here we review some of the mechanisms employed by the host and by pathogenic microorganisms to compete for transition metal ions, with a discussion of how evading nutritional immunity benefits pathogens. Furthermore, we provide new insights on the mechanisms of host-microbe competition for metal ions in the mucosa, particularly in the inflamed gut.

  13. Rational design of metal ion sequestering agents. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, K.N.

    1998-06-01

    'This project addresses fundamental issues and requirements in developing hazardous metal ion separation technologies needed in the treatment and disposal of radioactive and chemical toxic waste. It encompasses the synthesis of new agents, followed by their characterization and evaluation, with the aim to optimize their metal ion sequestering properties for use in applied technologies. This research is focused on the following key areas: (1) basic design and synthesis of new metal ion specific sequestering ligands; (2) structural and thermodynamic investigations of these ligands and their complexes formed with the targeted metal ions; and (3) development of sequestering agents and their incorporation into systems designed to be prototypes of inexpensive and highly effective materials for hazardous metal ion decontamination. Basic studies of the sequestration of relevant toxic metals are required in order to develop processes that will treat effluents sufficiently well to allow direct release into the environment and minimize the production of secondary wastes.'

  14. 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.

  15. N-phenylmaleimide as a New Ploymerizable Additive for Overcharge Protection of Lithium-ion Batteries

    Institute of Scientific and Technical Information of China (English)

    B.Wang; Q.Xia; Y.P.Wu

    2007-01-01

    1 Results In persuit of better safety controls of lithium batteries,much efforts has been focused on the development of the internal and self-actuating overcharge protection additives.We report a novel electropolymerizable electrolyte additive for overcharge protection of lithium batteries. Electrochemical properties and overcharge behavior of NPM as a new polymerizable electrolyte additive for overcharge protection of lithium ion batteries are studied by cyclic voltammetry,charge-discharge measurements...

  16. Lithium-Ion Electrolytes Containing Flame Retardant Additives for Increased Safety Characteristics

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Smith, Kiah A. (Inventor); Bugga, Ratnakumar V. (Inventor); Prakash, Surya G. (Inventor); Krause, Frederick Charles (Inventor)

    2014-01-01

    The invention discloses various embodiments of Li-ion electrolytes containing flame retardant additives that have delivered good performance over a wide temperature range, good cycle life characteristics, and improved safety characteristics, namely, reduced flammability. In one embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a fluorinated co-solvent, a flame retardant additive, and a lithium salt. In another embodiment of the invention there is provided an electrolyte for use in a lithium-ion electrochemical cell, the electrolyte comprising a mixture of an ethylene carbonate (EC), an ethyl methyl carbonate (EMC), a flame retardant additive, a solid electrolyte interface (SEI) film forming agent, and a lithium salt.

  17. 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......-terminus. CueR has a high selectivity for Cu+, Ag+ and Au+, but exhibits no transcriptional activity for the divalent ions Hg2+ and Zn2+.2 The two Cys- residues of the metal binding loop were shown to settle M+ ions into a linear coordination environment but other factors may also play a role in the recognition...

  18. Metal ions, not metal-catalyzed oxidative stress, cause clay leachate antibacterial activity.

    Directory of Open Access Journals (Sweden)

    Caitlin C Otto

    Full Text Available Aqueous leachates prepared from natural antibacterial clays, arbitrarily designated CB-L, release metal ions into suspension, have a low pH (3.4-5, generate reactive oxygen species (ROS and H2O2, and have a high oxidation-reduction potential. To isolate the role of pH in the antibacterial activity of CB clay mixtures, we exposed three different strains of Escherichia coli O157:H7 to 10% clay suspensions. The clay suspension completely killed acid-sensitive and acid-tolerant E. coli O157:H7 strains, whereas incubation in a low-pH buffer resulted in a minimal decrease in viability, demonstrating that low pH alone does not mediate antibacterial activity. The prevailing hypothesis is that metal ions participate in redox cycling and produce ROS, leading to oxidative damage to macromolecules and resulting in cellular death. However, E. coli cells showed no increase in DNA or protein oxidative lesions and a slight increase in lipid peroxidation following exposure to the antibacterial leachate. Further, supplementation with numerous ROS scavengers eliminated lipid peroxidation, but did not rescue the cells from CB-L-mediated killing. In contrast, supplementing CB-L with EDTA, a broad-spectrum metal chelator, reduced killing. Finally, CB-L was equally lethal to cells in an anoxic environment as compared to the aerobic environment. Thus, ROS were not required for lethal activity and did not contribute to toxicity of CB-L. We conclude that clay-mediated killing was not due to oxidative damage, but rather, was due to toxicity associated directly with released metal ions.

  19. Metal Ion Dependence of Cooperative Collapse Transitions in RNA

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, Sarvin; Caliskan, Gokhan; Chauhan, Seema; Hyeon, Changbong; Briber, R.M.; Thirumalai, D.; Woodson, Sarah A.; (Chung-Ang); (JHU); (Maryland)

    2010-10-12

    Positively charged counterions drive RNA molecules into compact configurations that lead to their biologically active structures. To understand how the valence and size of the cations influences the collapse transition in RNA, small-angle X-ray scattering was used to follow the decrease in the radius of gyration (R{sub g}) of the Azoarcus and Tetrahymena ribozymes in different cations. Small, multivalent cations induced the collapse of both ribozymes more efficiently than did monovalent ions. Thus, the cooperativity of the collapse transition depends on the counterion charge density. Singular value decomposition of the scattering curves showed that folding of the smaller and more thermostable Azoarcus ribozyme is well described by two components, whereas collapse of the larger Tetrahymena ribozyme involves at least one intermediate. The ion-dependent persistence length, extracted from the distance distribution of the scattering vectors, shows that the Azoarcus ribozyme is less flexible at the midpoint of transition in low-charge-density ions than in high-charge-density ions. We conclude that the formation of sequence-specific tertiary interactions in the Azoarcus ribozyme overlaps with neutralization of the phosphate charge, while tertiary folding of the Tetrahymena ribozyme requires additional counterions. Thus, the stability of the RNA structure determines its sensitivity to the valence and size of the counterions.

  20. Localization of dislocation-related luminescence centers in self-ion implanted silicon and effect of additional boron ion doping

    Energy Technology Data Exchange (ETDEWEB)

    Tetelbaum, D.I.; Mikhaylov, A.N.; Belov, A.I.; Korolev, D.S.; Shushunov, A.N.; Bobrov, A.I.; Pavlov, D.A. [Lobachevsky State University of Nizhni Novgorod (Russian Federation); Shek, E.I.; Sobolev, N.A. [Ioffe Physical Technical Institute, St. Petersburg (Russian Federation)

    2015-01-01

    The depth distribution of light-emitting centers of the D1 dislocation-related photoluminescence line (∝ 1.5 μm) in silicon implanted with Si{sup +} ions and annealed at 1100 C in the oxidizing chlorine-containing atmosphere has been investigated by means of the layer-by-layer chemical etching. It is established with the application of cross-sectional transmission electron microscopy that the main contribution to the D1 line is made by the centers located at the depths of up to ∝ 150 nm, i.e. in the region of Si{sup +} ion ranges, whereas the dislocations produced by Si{sup +} implantation and annealing at 1100 C penetrate to the depth of ∝ 1000 nm. Additional boron ion doping with subsequent annealing at 800 C in N{sub 2} atmosphere improves the emission in comparison with the undoped but annealed reference sample, however the additional annealing at 800 C per se results in the photoluminescence weakening. The dependence of the D1 line intensity on boron ion dose is found to be nonmonotonous. The interpretation of the obtained results is given in relation to the key role of selfinterstitials and boron impurity in the formation of radiative and nonradiative centers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. MeRNA: a Database of Metal Ion Binding Sites in RNAStructures

    Energy Technology Data Exchange (ETDEWEB)

    Stefan, Liliana R.; Zhang, Rui; Levitan, Aaron G.; Hendrix, DonnaF.; Brenner, Steven E.; Holbrook, Stephen R.

    2005-10-05

    Metal ions are essential for the folding of RNA into stable tertiary structures and for the catalytic activity of some RNA enzymes. To aid in the study of the roles of metal ions in RNA structural biology, we have created MeRNA (Metals in RNA), a comprehensive compilation of all metal binding sites identified in RNA three-dimensional structures available from the Protein Data Bank (PDB) and Nucleic Acid Database (NDB). Currently, our database contains information relating to binding of 9764 metal ions corresponding to 23 distinct elements; in 256 RNA structures. The metal ion locations were confirmed and ligands characterized using original literature references. MeRNA includes eight manually identified metal-ion binding motifs, which are described in the literature. MeRNA is searchable by PDB identifier, metal ion, method of structure determination, resolution and R-values for X-ray structure, and distance from metal to any RNA atom or to water. New structures with their respective binding motifs will be added to the database as they become available. The MeRNA database will further our understanding of the roles of metal ions in RNA folding and catalysis and have applications in structural and functional analysis, RNA design and engineering.

  2. Process for the displacement of cyanide ions from metal-cyanide complexes

    Science.gov (United States)

    Smith, Barbara F.; Robinson, Thomas W.

    1997-01-01

    The present invention relates to water-soluble polymers and the use of such water-soluble polymers in a process for the displacement of the cyanide ions from the metal ions within metal-cyanide complexes. The process waste streams can include metal-cyanide containing electroplating waste streams, mining leach waste streams, mineral processing waste streams, and related metal-cyanide containing waste streams. The metal ions of interest are metals that give very strong complexes with cyanide, mostly iron, nickel, and copper. The physical separation of the water-soluble polymer-metal complex from the cyanide ions can be accomplished through the use of ultrafiltration. Once the metal-cyanide complex is disrupted, the freed cyanide ions can be recovered for reuse or destroyed using available oxidative processes rendering the cyanide nonhazardous. The metal ions are released from the polymer, using dilute acid, metal ion oxidation state adjustment, or competing chelating agents, and collected and recovered or disposed of by appropriate waste management techniques. The water-soluble polymer can then be recycled. Preferred water-soluble polymers include polyethyleneimine and polyethyleneimine having a catechol or hydroxamate group.

  3. The Relationship of Culture Media Composition and Chemical Composition on Spirulina sp for Metal Ion Adsorbent

    Directory of Open Access Journals (Sweden)

    Hilda Zulkifli

    2016-12-01

    Full Text Available The analysis relationship of Spirulina sp medium with chemical composition has been conducted. Chemical analysis was performed using X-Ray Fluorescence analysis. Furthermore, potention of Spirulina sp as adsorbent of metal ions was analyzed using FTIR spectroscopy. The results showed that metals such as Zn, Fe, Mn, Ca, Cu, and Mo were mainly metals in Spirulina sp. These metals were not correlated with cultivated medium of Spirulina sp. Analysis of potention Spirulina sp as metal ions adsorbent showed that Spirulina sp has functional groups –C=O and –OH as ligand. Intercation of metal ions Cu(II and Cr(III with Spirulina sp indicated that metal ions bond to –C=O functional group.

  4. Xylene as a New Polymerizable Additive for Overcharge Protection of Lithium Ion Batteries

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qianyu; QIU Chenchen; FU Yanbao; MA Xiaohua

    2009-01-01

    The electrochemical properties and overcharge protection mechanism of xylene as a new polymerizable electrolyte additive for overcharge protection of lithium ion batteries were studied by cyclic voltammetry tests,chargedischarge performance and battery power capacity measurements.It was found that when the battery was overcharged,xylene could electrochemically polymerize at the overcharge potential of 4.3-4.7 V (vs.Li/Li+) to form a thin polymer film on the surface of the cathode,thus preventing voltage runaway.On the other hand,the use of xylene as an overcharge protection electrolyte additive did not influence the normal performance of lithium ion batteries.

  5. Heterogeneous behavior of metalloproteins toward metal ion binding and selectivity: insights from molecular dynamics studies.

    Science.gov (United States)

    Gogoi, Prerana; Chandravanshi, Monika; Mandal, Suraj Kumar; Srivastava, Ambuj; Kanaujia, Shankar Prasad

    2016-07-01

    About one-third of the existing proteins require metal ions as cofactors for their catalytic activities and structural complexities. While many of them bind only to a specific metal, others bind to multiple (different) metal ions. However, the exact mechanism of their metal preference has not been deduced to clarity. In this study, we used molecular dynamics (MD) simulations to investigate whether a cognate metal (bound to the structure) can be replaced with other similar metal ions. We have chosen seven different proteins (phospholipase A2, sucrose phosphatase, pyrazinamidase, cysteine dioxygenase (CDO), plastocyanin, monoclonal anti-CD4 antibody Q425, and synaptotagmin 1 C2B domain) bound to seven different divalent metal ions (Ca(2+), Mg(2+), Zn(2+), Fe(2+), Cu(2+), Ba(2+), and Sr(2+), respectively). In total, 49 MD simulations each of 50 ns were performed and each trajectory was analyzed independently. Results demonstrate that in some cases, cognate metal ions can be exchanged with similar metal ions. On the contrary, some proteins show binding affinity specifically to their cognate metal ions. Surprisingly, two proteins CDO and plastocyanin which are known to bind Fe(2+) and Cu(2+), respectively, do not exhibit binding affinity to any metal ion. Furthermore, the study reveals that in some cases, the active site topology remains rigid even without cognate metals, whereas, some require them for their active site stability. Thus, it will be interesting to experimentally verify the accuracy of these observations obtained computationally. Moreover, the study can help in designing novel active sites for proteins to sequester metal ions particularly of toxic nature.

  6. 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

  7. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Suryanti, Venty, E-mail: venty@mipa.uns.ac.id; Hastuti, Sri; Pujiastuti, Dwi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Sebelas Maret University Jl. Ir. Sutami 36A, Surakarta, Central Java 57126 (Indonesia)

    2016-02-08

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  8. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Science.gov (United States)

    Suryanti, Venty; Hastuti, Sri; Pujiastuti, Dwi

    2016-02-01

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  9. Competitive adsorption of heavy metal ions on peat

    Institute of Scientific and Technical Information of China (English)

    LIU Zhi-rong; ZHOU Li-min; WEI Peng; ZENG Kai; WEN Chuan-xi; LAN Hui-hua

    2008-01-01

    The uptake capacities, and the adsorption kinetics, of copper, Cu(Ⅱ), nickel, Ni(Ⅱ), and cadmium, Cd(Ⅱ), on peat have been studied under static conditions. The results show that the adsorption rates are rapid: equilibrium is reached in twenty minutes. The adsorption of copper, nickel and cadmium is pH dependent over the pH range from 2 to 6. The adsorption kinetics can be excellently described by the Elovich kinetic equation. The adsorption isotherm fits a Langmuir model very well. The adsorption capacifies follow the order Cu2+>Ni2+>Cd2+ in single-component systems and the competitive adsorption capacities fall in the decreasing order Cu2+> Ni2+>Cd2+ in multi-component systems. The adsorption capacities of these three heavy metal ions on peat are consistent with their observed competitive adsorption capacities.

  10. Surface modification by metal ion implantation forming metallic nanoparticles in an insulating matrix

    Science.gov (United States)

    Salvadori, M. C.; Teixeira, F. S.; Sgubin, L. G.; Cattani, M.; Brown, I. G.

    2014-08-01

    There is special interest in the incorporation of metallic nanoparticles in a surrounding dielectric matrix for obtaining composites with desirable characteristics such as for surface plasmon resonance, which can be used in photonics and sensing, and controlled surface electrical conductivity. We have investigated nanocomposites produced by metal ion implantation into insulating substrates, where the implanted metal self-assembles into nanoparticles. The nanoparticles nucleate near the maximum of the implantation depth profile (projected range), which can be estimated by computer simulation using the TRIDYN code. TRIDYN is a Monte Carlo simulation program based on the TRIM (Transport and Range of Ions in Matter) code that takes into account compositional changes in the substrate due to two factors: previously implanted dopant atoms, and sputtering of the substrate surface. Our study show that the nanoparticles form a bidimentional array buried a few nanometers below the substrate surface. We have studied Au/PMMA (polymethylmethacrylate), Pt/PMMA, Ti/alumina and Au/alumina systems. Transmission electron microscopy of the implanted samples show that metallic nanoparticles form in the insulating matrix. These nanocomposites have been characterized by measuring the resistivity of the composite layer as a function of the implantation dose. The experimental results are compared with a model based on percolation theory, in which electron transport through the composite is explained by conduction through a random resistor network formed by the metallic nanoparticles. Excellent agreement is found between the experimental results and the predictions of the theory. We conclude in that the conductivity process is due only to percolation (when the conducting elements are in geometric contact) and that the contribution from tunneling conduction is negligible.

  11. Metals Additive ManufacturingGreat Promise in Mitigating Shortages but Some Risks Remain

    Science.gov (United States)

    2016-12-01

    metals AM such as Selective Laser Melting, Laser Cutting, Direct Metal Laser Sintering and Electron Beam Melting (EBM) and collectively refers to...welding approach during which a computer-controlled laser or electron beam is moved over a bed of powder, fusing or sintering the powder selec- tively to...Group Figure 1. The Powder Bed Metal Fusion Additive Manufacturing Process Laser Unsintered material in previous layers Roller Laser

  12. Ion mobility studies of carbohydrates as group I adducts: isomer specific collisional cross section dependence on metal ion radius.

    Science.gov (United States)

    Huang, Yuting; Dodds, Eric D

    2013-10-15

    Carbohydrates play numerous critical roles in biological systems. Characterization of oligosaccharide structures is essential to a complete understanding of their functions in biological processes; nevertheless, their structural determination remains challenging in part due to isomerism. Ion mobility spectrometry provides the means to resolve gas phase ions on the basis of their shape-to-charge ratios, thus providing significant potential for separation and differentiation of carbohydrate isomers. Here, we report on the determination of collisional cross sections for four groups of isomeric carbohydrates (including five isomeric disaccharides, four isomeric trisaccharides, two isomeric pentasaccharides, and two isomeric hexasaccharides) as their group I metal ion adducts (i.e., [M + Li](+), [M + Na](+), [M + K](+), [M + Rb](+), and [M + Cs](+)). In all, 65 collisional cross sections were measured, the great majority of which have not been previously reported. As anticipated, the collisional cross sections of the carbohydrate metal ion adducts generally increase with increasing metal ion radius; however, the collisional cross sections were found to scale with the group I cation size in isomer specific manners. Such measurements are of substantial analytical value, as they illustrate how the selection of charge carrier influences carbohydrate ion mobility determinations. For example, certain pairs of isomeric carbohydrates assume unique collisional cross sections upon binding one metal ion, but not another. On the whole, these data suggest a role for the charge carrier as a probe of carbohydrate structure and thus have significant implications for the continued development and application of ion mobility spectrometry for the distinction and resolution of isomeric carbohydrates.

  13. The involvement of transition metal ions on iron-dependent lipid peroxidation.

    Science.gov (United States)

    Repetto, Marisa G; Ferrarotti, Nidia F; Boveris, Alberto

    2010-04-01

    The metals iron (Fe) and copper (Cu) are considered trace elements, and the metals cobalt (Co) and nickel (Ni) are known as ultra-trace elements, considering their presence in low to very low quantity in humans. The biologic activity of these transition metals is associated with the presence of unpaired electrons that favor their participation in redox reactions. They are part of important enzymes involved in vital biologic processes. However, these transition metals become toxic to cells when they reach elevated tissue concentrations and produce cellular oxidative damage. Phospholipid liposomes (0.5 mg/ml, phosphatidylcholine (PC)/phosphatidylserine (PS), 60/40) were incubated for 60 min at 37 degrees C with 25 microM of Fe2+ in the absence and in the presence of Cu2+, Co2+, and Ni2+ (0-100 microM) with and without the addition of hydrogen peroxide (H2O2, 5-50 microM). Iron-dependent lipid peroxidation in PC/PS liposomes was assessed by thiobarbituric acid-reactive substances (TBARS) production. Metal transition ions promoted lipid peroxidation by H2O2 decomposition and direct homolysis of endogenous hydroperoxides. The Fe2+-H2O2-mediated lipid peroxidation takes place by a pseudo-second order process, and the Cu2+-mediated process by a pseudo-first order reaction. Co2+ and Ni2+ alone do not induce lipid peroxidation. Nevertheless, when they are combined with Fe2+, Fe2+-H2O2-mediated lipid peroxidation was stimulated in the presence of Ni2+ and was inhibited in the presence of Co2+. The understanding of the effects of transition metal ions on phospholipids is relevant to the prevention of oxidative damage in biologic systems.

  14. Towards a model of non-equilibrium binding of metal ions in biological systems.

    Science.gov (United States)

    Beardmore, James; Exley, Christopher

    2009-02-01

    We have used a systems biology approach to address the hitherto insoluble problem of the quantitative analysis of non-equilibrium binding of aqueous metal ions by competitive ligands in heterogeneous media. To-date, the relative proportions of different metal complexes in aqueous media has only been modelled at chemical equilibrium and there are no quantitative analyses of the approach to equilibrium. While these models have improved our understanding of how metals are used in biological systems they cannot account for the influence of kinetic factors in metal binding, transport and fate. Here we have modelled the binding of aluminium, Al(III), in blood serum by the iron transport protein transferrin (Tf) as it is widely accepted that the biological fate of this non-essential metal is not adequately described by experiments, invitro and insilico, which have consistently demonstrated that at equilibrium 90% of serum Al(III) is bound by Tf. We have coined this paradox 'the blood-aluminium problem' and herein applied a systems biology approach which utilised well-found assumptions to pare away the complexities of the problem such that it was defined by a comparatively simple set of computational rules and, importantly, its solution assumed significant predictive capabilities. Here we show that our novel computational model successfully described the binding of Al(III) by Tf both at equilibrium and as equilibrium for Al(Tf) was approached. The model predicted significant non-equilibrium binding of Al by ligands in competition with Tf and, thereby, provided an explanation of why the distribution of Al(III) in the body cannot be adequately described by its binding and transport by Tf alone. Generically the model highlighted the significance of kinetic in addition to thermodynamic constraints in defining the fate of metal ions in biological systems.

  15. Solvent and metal ion effects on the conformation of cyclosporin

    Science.gov (United States)

    Shaw, R. A.; Mantsch, Henry H.; Chowdhry, Babur Z.

    1994-01-01

    Infrared spectra of cyclosporin A (CsA) and three analogues CsC, CsD, and CsH have been measured (1) in a variety of organic solvents, and (2) in acetonitrile in the presence of lithium, sodium, magnesium, and calcium ions. The amide I (CequalsO stretching) absorption pattern shows a systematic trend with increasing solvent polarity. The spectral changes indicate that polar solvents disrupt two of the four intramolecular hydrogen bonds, leaving the first two hydrogen bonds of the (beta) -sheet structure intact. Interaction of CsA, CsC, or CsD with the monovalent cations Li+ and Na+ in acetonitrile yields spectra that are virtually identical to one another. The spectra suggest that several carbonyl groups bind simultaneously to the metal ion. In contrast the spectra suggest strong binding by Ca2+ and Mg2+ to one or two specific CequalsO groups, as evidenced by very low frequency CequalsO stretching bands observed at ca. 1600 cm-1.

  16. 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

    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 ion...

  17. "Anion clamp" allows flexible protein to impose coordination geometry on metal ions.

    Science.gov (United States)

    Wang, Minji; Lai, Tsz Pui; Wang, Li; Zhang, Hongmin; Yang, Nan; Sadler, Peter J; Sun, Hongzhe

    2015-05-01

    X-ray crystal structures of human serum transferrin (77 kDa) with Yb(III) or Fe(III) bound to the C-lobe and malonate as the synergistic anion show that the large Yb(III) ion causes the expansion of the metal binding pocket while octahedral metal coordination geometry is preserved, an unusual geometry for a lanthanide ion.

  18. Effects of Lability of Metal Complex on Free Ion Measurement Using DMT

    NARCIS (Netherlands)

    Weng, L.P.; Riemsdijk, van W.H.; Temminghoff, E.J.M.

    2010-01-01

    Very low concentrations of free metal ion in natural samples can be measured using the Donnan membrane technique (DMT) based on ion transport kinetics. In this paper, the possible effects of slow dissociation of metal complexes on the interpretation of kinetic DMT are investigated both theoretically

  19. Measuring free metal ion concentrations in multicomponent solutions using Donnan Membrane Technique

    NARCIS (Netherlands)

    Kalis, E.J.J.; Temminghoff, E.J.M.; Weng, L.P.; Riemsdijk, van W.H.

    2007-01-01

    Among speciation techniques that are able to measure free metal ion concentrations, the Donnan membrane technique (DMT) has the advantage that it can measure many different free metal ion concentrations simultaneously in a multicomponent sample. Even though the DMT has been applied to several system

  20. Theoretical study on hydrogenation catalysts containing a metal hydride as additional hydrogen supply

    NARCIS (Netherlands)

    Snijder, E.D.; Versteeg, G.F.; Swaaij, W.P.M. van

    1992-01-01

    A hypothetical hydrogenation catalyst consisting of porous, catalytically active particles embedded with metal hydride powder was evaluated. The metal hydride provides temporarily additional hydrogen if the mass transfer rate of the hydrogen to the internal of the particle is not sufficient. A numer

  1. Metal Ions Removal Using Nano Oxide Pyrolox™ Material

    Science.gov (United States)

    Gładysz-Płaska, A.; Skwarek, E.; Budnyak, T. M.; Kołodyńska, D.

    2017-02-01

    The paper presents the use of Pyrolox™ containing manganese nano oxides used for the removal of Cu(II), Zn(II), Cd(II), and Pb(II) as well as U(VI) ions. Their concentrations were analyzed using the atomic absorption spectrometer SpectrAA 240 FS (Varian) as well as UV-vis method. For this purpose the static kinetic and equilibrium studies were carried out using the batch technique. The effect of solution pH, shaking time, initial metal ion concentrations, sorbent dosage, and temperature was investigated. The equilibrium data were analyzed using the sorption isotherm models proposed by Freundlich, Langmuir-Freundlich, Temkin, and Dubinin-Radushkevich. The kinetic results showed that the pseudo second order kinetic model was found to correlate the experimental data well. The results indicate that adsorption of Cu(II), Zn(II), Cd(II), and Pb(II) as well as U(VI) ions is strongly dependent on pH. The value of pH 4-7 was optimal adsorption. The time to reach the equilibrium was found to be 24 h, and after this time, the sorption percentage reached about 70%. Kinetics of Cu(II), Zn(II), Cd(II), Pb(II), and U(VI) adsorption on the adsorbent can be described by the pseudo second order rate equation. Nitrogen adsorption/desorption, infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) measurements for adsorbent characterization were performed. Characteristic points of the double layer determined for the studied Pyrolox™ sample in 0.001 mol/dm3 NaCl solution are pHPZC = 4 and pHIEP < 2.

  2. Reactions of metal ions at surfaces of hydrous iron oxide

    Science.gov (United States)

    Hem, J.D.

    1977-01-01

    Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10-8.00 or 10-9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn3O4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10-9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems. ?? 1977.

  3. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

    Picart, S.; Parant, P.; Caisso, M.; Remy, E.; Mokhtari, H.; Jobelin, I.; Bayle, J. P.; Martin, C. L.; Blanchart, P.; Ayral, A.; Delahaye, T.

    2015-07-01

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of flowability for the filling of compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 °C and temperature rate lower than 2 °C/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density (TD) and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner.

  4. Polyazulene based materials for heavy metal ions detection

    Science.gov (United States)

    Oprisanu, A.; Ungureanu, E. M.; Isopescu, R.; Birzan, L.; Mihai, M.; Vasiliu, C.

    2017-06-01

    Azulene is a special monomer used to functionalize electrodes, due to its spontaneous electron drift from the seven-membered ring to the five-membered ring. The seven-membered ring of the molecule may act as electron acceptor, while the five-membered ring - as electron donor. This leads to very attractive properties for the synthesis of functional advanced materials like: materials with nonlinear optical and photorefractive properties, cathode materials for lithium batteries, or light emitting diodes based on organic materials. Azulene derivatives have been used rarely to the metal ions electroanalysis. Our study concerns the synthesis and electrochemical characterization of a new azulene based monomer 4-(azulen-1-yl)-2,6-bis((E)-2-(thiophen-3-yl)vinyl)pyridine (L). L has been used to obtain modified electrodes by electrochemical polymerization. PolyL films modified electrodes have been characterized by cyclic voltammetry in ferrocene solutions. The complexing properties of polyL based functional materials have been investigated towards heavy metals (Pb, Cd Hg, Cu) by preconcentration - anodic stripping technique in order to analyze the content of these cations from water samples.

  5. Alkyl Pyrocarbonate Electrolyte Additives for Performance Enhancement of Li Ion Cells

    Science.gov (United States)

    Smart, M. C.; Ratnakumar, B. V.; Surampudi, S.

    2000-01-01

    Lithium ion rechargeable batteries are being developed for various aerospace applications under a NASA-DoD Interagency program. These applications require further improvements in several areas, specifically in the cycle life for LEO and GEO satellites and in the low temperature performance for the Mars Lander and Rover missions. Accordingly, we have been pursuing research studies to achieve improvement in the low temperature performance, long cycle life and active life of Li ion cells. The studies are mainly focused on electrolytes, to identify newer formulations of new electrolyte additives to enhance Li permeability (at low temperatures) and stability towards the electrode. The latter approach is particularly aimed at the formation suitable SEI (solid electrolyte interphase) on carbon electrodes. In this paper, we report the beneficial effect of using alkyl pyrocarbonates as electrolyte additives to improve the low temperature performance of Li ion cells.

  6. Feasibility Study on 3-D Printing of Metallic Structural Materials with Robotized Laser-Based Metal Additive Manufacturing

    Science.gov (United States)

    Ding, Yaoyu; Kovacevic, Radovan

    2016-07-01

    Metallic structural materials continue to open new avenues in achieving exotic mechanical properties that are naturally unavailable. They hold great potential in developing novel products in diverse industries such as the automotive, aerospace, biomedical, oil and gas, and defense. Currently, the use of metallic structural materials in industry is still limited because of difficulties in their manufacturing. This article studied the feasibility of printing metallic structural materials with robotized laser-based metal additive manufacturing (RLMAM). In this study, two metallic structural materials characterized by an enlarged positive Poisson's ratio and a negative Poisson's ratio were designed and simulated, respectively. An RLMAM system developed at the Research Center for Advanced Manufacturing of Southern Methodist University was used to print them. The results of the tensile tests indicated that the printed samples successfully achieved the corresponding mechanical properties.

  7. Functional Mesoporous Metal-Organic Frameworks for the Capture of Heavy Metal Ions and Size-Selective Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Qian-Rong; Yuan, Daqiang; Sculley, Julian; Li, Jian-Rong; Han, Zheng-Bo; Zhou, Hong-Cai

    2010-12-20

    By using Zn₄O(CO₂)₆ as secondary building units (SBUs) and two extended ligands containing amino functional groups, TATAB and BTATB (TATAB = 4,4',4''-s-triazine-1,3,5-triyltri-p-aminobenzoate and BTATB = 4,4',4''-(benzene-1,3,5-triyltris(azanediyl))tribenzoate), two isostructural mesoporous metal–organic frameworks (MOFs) with cavities up to 2.73 nm, designated as PCN-100 and PCN-101 (PCN represents porous coordination network), have been synthesized. N₂ sorption isotherms of both PCN-100 and -101 showed typical type IV behavior, indicating their mesoporous nature. The TATAB ligand that comprises PCN-100 was employed to capture heavy metal ions (Cd(II) and Hg(II)) by constructing complexes within the pores with a possible coordination mode similar to that found in aminopyridinato complexes. This reveals that mesoporous materials such as PCN-100 can be applied in the elimination of heavy metal ions from waste liquid. In addition, both PCNs-100 and -101 exhibit size-selective catalytic activity toward the Knoevenagel condensation reaction.

  8. Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Soriano, Maria C., E-mail: maria.HernandezSoriano@ees.kuleuven.be [Department of Soil Science, College of Agriculture and Life Sciences, North Carolina State University, Campus Box 7619, 101 Derieux Street, 2232 Williams Hall, Raleigh, NC 27695 (United States); Jimenez-Lopez, Jose C. [Department of Biological Sciences, College of Science, Purdue University, 201 S. University Street, West Lafayette, IN 47907 (United States)

    2012-04-15

    The mobility and bioavailability of cadmium, copper, lead and zinc were evaluated in three soils amended with different organic materials for two moisture regimes. Agricultural and reclamation activities impose fresh inputs of organic matter on soil while intensive irrigation and rainstorm increase soil waterlogging incidence. Moreover, scarcity of irrigation water has prompted the use of greywater, which contain variable concentrations of organic compounds such as anionic surfactants. Soils added with hay, maize straw or peat at 1% w/w were irrigated, at field capacity (FC) or saturated (S), with an aqueous solution of the anionic surfactant Aerosol 22 (A22), corresponding to an addition of 200 mg C/kg soil/day. Soil solution was extracted after one month and analysed for total soluble metals, dissolved soil organic matter and UV absorbance at 254 nm. Speciation analyses were performed with WHAM VI for Cd, Cu, Pb, and Zn. For selected scenarios, metal uptake by barley was determined. Metal mobility increased for all treatments and soils (Pb > Cu > Cd {>=} Zn) compared to control assays. The increase was significantly correlated (p < 0.05) with soil organic matter solubilisation for Cd (R = 0.68), Cu (R = 0.73) and Zn (R = 0.86). Otherwise, Pb release was related to aluminium solubilisation (R = 0.75), which suggests that Pb was originally co-precipitated with Al-DOC complexes in the solid phase. The effect of A22 in metal bioavailability, determined as free ion activities (FIA), was mainly controlled by soil moisture regime. For soil 3, metal bioavailability was up to 20 times lower for soil amended with hay, peat or maize compared to soil treated only with A22. When soil was treated with A22 at FC barley yield significantly decreased (p < 0.05) for the increase of Pb (R = 0.71) and Zn (R = 0.79) concentrations in shoot, while for saturated conditions such uptake was up to 3 times lower. Overall, metal bioavailability was controlled by solubilisation of soil

  9. 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)

  10. Protein-responsive assemblies from catechol-metal ion supramolecular coordination.

    Science.gov (United States)

    Yuan, C; Chen, J; Yu, S; Chang, Y; Mao, J; Xu, Y; Luo, W; Zeng, B; Dai, L

    2015-03-21

    Supramolecular self-assembly driven by catechol-metal ion coordination has gained great success in the fabrication of functional materials including adhesives, capsules, coatings and hydrogels. However, this route has encountered a great challenge in the construction of nanoarchitectures in the absence of removable templates, because of the uncontrollable crosslinking of catechol-metal ion coordination. Herein, we show that a supramolecular approach, combining both catechol-metal ion coordination and polymer self-assembly together, can organize polymers into hybrid nanoassemblies ranging from solid particles, homogeneous vesicles to Janus vesicles. Without the introduction of a specific binding ligand or complicated molecular design, these assemblies can totally disassemble in response to proteins. UV/vis absorption, fluorescence quenching and recovery investigations have confirmed that proteins can seize metal ions from the hybrid nanoassemblies, thus causing the degradation of catechol-metal ion coordination networks.

  11. Electrochemical Metal Ion Sensors. Exploiting Amino Acids and Peptides as Recognition Elements

    Directory of Open Access Journals (Sweden)

    Wenrong Yang

    2001-08-01

    Full Text Available Amino acids and peptides are known to bind metal ions, in some cases very strongly. There are only a few examples of exploiting this binding in sensors. The review covers the current literature on the interaction of peptides and metals and the electrochemistry of bound metal ions. Peptides may be covalently attached to surfaces. Of particular interest is the attachment to gold via sulfur linkages. Sulfur-containing peptides (eg cysteine may be adsorbed directly, while any amino group can be covalently attached to a carboxylic acid-terminated thiol. Once at a surface, the possibility for using the attached peptide as a sensor for metal ions becomes realised. Results from the authors’ laboratory and elsewhere have shown the potential for selective monitoring of metal ions at ppt levels. Examples of the use of poly-aspartic acid and the copper binding peptide Gly-Gly-His for detecting copper ions are given.

  12. 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

  13. Interacion of Heavy Metal Ions with C-Phycocyanin: Binding Isotherms and Cooperative Effects

    CERN Document Server

    Gelagutashvili, Eteri

    2007-01-01

    The binding constant of copper(II) ions to C-PC were determined at different ionic strengths from binding isotherms by equilibrium dialysis and flame atomic absorption spectroscopy. Fluorescence and absorbtion spectroscopy provides insight of metal-C-phycocyanin interactions. Fluorescence measurements demonstrate C-PC quenching of heavy metal ions emission intensities. Stern-Volmer quenching constants were obtained from the linear quenching plots. Blue shifts in the fluorescence spectra were observed during metal binding to C-PC. It was shown, that between bound metal ions in C-PC there exists positive cooperativity.

  14. Sunflower stalks as adsorbents for the removal of metal ions from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Sun, G.; Shi, W. [Univ. of California, Davis, CA (United States). Div. of Textiles and Clothing

    1998-04-01

    Sunflower stalks as adsorbents for the removal of metal ions such as copper, cadmium, zinc, and chromium ions in aqueous solutions were studied with equilibrium isotherms and kinetic adsorptions. The maximum adsorptions of four heavy metals are 29.3 mg/g (Cu{sup 2+}), 30.73 mg/g (Zn{sup 2+}), 42.18 mg/g (Cd{sup 2+}), and 25.07 mg/g (Cr{sup 3+}), respectively. Particle sizes of sunflower stalks affected the adsorption of metal ions; the finer size of particles showed better adsorption to the ions. Temperature also plays an interesting role in the adsorption of different metal ions. Copper, zinc, and cadmium exhibited lower adsorption on sunflower stalks at higher temperature, while chromium showed the opposite phenomenon. The adsorption rates of copper, cadmium, and chromium are quite rapid. Within 60 min of operation about 60--80% of these ions were removed from the solutions.

  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

    in the mutant receptors not by normal catecholamine ligands but instead either by free zinc ions or by zinc or copper ions in complex with small hydrophobic metal-ion chelators. Chelation of the metal ions by small hydrophobic chelators such as phenanthroline or bipyridine protected the cells from the toxic......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. Role of ATP-bound divalent metal ion in the conformation and function of actin. Comparison of Mg-ATP, Ca-ATP, and metal ion-free ATP-actin.

    Science.gov (United States)

    Valentin-Ranc, C; Carlier, M F

    1991-04-25

    The fluorescence of N-acetyl-N'-(sulfo-1-naphthyl)ethylenediamine (AEDANS) covalently bound to Cys-374 of actin is used as a probe for different conformational states of G-actin according to whether Ca-ATP, Mg-ATP, or unchelated ATP is bound to the nucleotide site. Upon addition of large amounts (greater than 10(2)-fold molar excess) of EDTA to G-actin, metal ion-free ATP-G-actin is obtained with EDTA bound. Metal ion free ATP-G-actin is characterized by a higher AEDANS fluorescence than Mg-ATP-G-actin, which itself has a higher fluorescence than Ca-ATP-G-actin. Evidence for EDTA binding to G-actin is shown using difference spectrophotometry. Upon binding of EDTA, the rate of dissociation of the divalent metal ion from G-actin is increased (2-fold for Ca2+, 10-fold for Mg2+) in a range of pH from 7.0 to 8.0. A model is proposed that quantitatively accounts for the kinetic data. The affinity of ATP is weakened 10(6)-fold upon removal of the metal ion. Metal ion-free ATP-G-actin is in a partially open conformation, as indicated by the greater accessibility of -SH residues, yet it retains functional properties of polymerization and ATP hydrolysis that appear almost identical to those of Ca-ATP-actin, therefore different from those of Mg-ATP-actin. These results are discussed in terms of the role of the ATP-bound metal ion in actin structure and function.

  17. A scale of metal ion binding strengths correlating with ionic charge, Pauling electronegativity, toxicity, and other physiological effects.

    Science.gov (United States)

    Kinraide, Thomas B; Yermiyahu, Uri

    2007-09-01

    Equilibrium constants for binding to plant plasma membranes have been reported for several metal ions, based upon adsorption studies and zeta-potential measurements. LogK values for the ions are these: Al(3+), 4.30; La(3+), 3.34; Cu(2+), 2.60; Ca(2+) and Mg(2+), 1.48; Na(+) and K(+), 0 M(-1). These values correlate well with logK values for ion binding to many organic and inorganic ligands. LogK values for metal ion binding to 12 ligands were normalized and averaged to produce a scale for the binding of 49 ions. The scale correlates well with the values presented above (R(2)=0.998) and with ion binding to cell walls and other biomass. The scale is closely related to the charge (Z) and Pauling electronegativity (PE) of 48 ions (all but Hg(2+)); R(2)=0.969 for the equation (Scale values)=-1.68+Z(1.22+0.444PE). Minimum rhizotoxicity of metal ions appears to be determined by binding strengths: log a(PM,M)=1.60-2.41exp[0.238(Scale values)] determines the value of ion activities at the plasma membrane surface (a(PM,M)) that will ensure inhibition of root elongation. Additional toxicity appears to be related to softness, accounting for the great toxicity of Ag(+), for example. These binding-strength values correlate with additional physiological effects and are suitable for the computation of cell-surface electrical potentials.

  18. Thermal and fragility aspects of microwave synthesized glasses containing transition metal ions and heavy metal ions

    Science.gov (United States)

    Renuka, C.; Viswanatha, R.; Reddy, C. Narayana

    2017-02-01

    A simple, clean and energy efficient microwave heating route is used to prepare glasses in the systems xMnO-33(0.09PbCl2:0.91PbO)-(67-x) NaPO3 and xPbCl2-33PbO-(67-x) NaPO3 where 0.1 ≤ x ≤ 4 (mol%). Thermal data extracted from differential scanning calorimetry (DSC) thermograms are used to study the composition dependence of glass transition temperature (Tg), heat capacity, thermal stability and fragility. The decrease in glass transition temperature with modifier oxide (Na2O + MnO) content can be ascribed to network degradation and the volume increasing effect caused by PbCl2. The change in heat capacity of MnPb glass being greater than that of PbNP glass, suggests that MnPb glasses are more covalent than PbNP glasses. DSC thermograms taken at different heating rates (φ) reveal the dependence of Tg on φ, and the thermal stability of the glass increases due to MnO addition. Fragility aspects have also been studied by calculating the fragility functions ( {{Δ {{C}}_{{p}} }/{{{C}_{{pl}} }}{{and}}{[ {{NBO}} ]}/{{{V}_{{m}}3 {{T}}_{{g}} }}} ). Results obtained from both the fragility functions compare well and reveal the dependence of fragility functions on modifier content and PbCl2 mol%. Further, the decrease in Tg and Hv are suggested to be due to the increase in the number of non-bridging oxygens, which results in the lowering of stiffness and rigidity of the glass network. Analysis of the infrared spectra confirms that the glassy matrix is composed of P-O-P, P-O-Pb, P=O and P-O- bonding.

  19. Synthesis of amino-functionalized mesoporous silica sheets and their application for metal ion capture

    Directory of Open Access Journals (Sweden)

    Kazuma Nakanishi

    2015-03-01

    Full Text Available Novel mesoporous silica sheets with surface amino-functional groups (sheet-NH2 were prepared for the efficient adsorption of aqueous metal ions. The sheet-NH2 were synthesized by a dual-templating process using Pluronic P123 and N-palmitoyl-l-alanine as templates. Two silicone regents were used to form the silica framework: tetraethoxysilane and 3-aminopropyltriethoxysilane. In the synthetic process, the as-prepared silicate was refluxed in ethanol to remove the organic templates remaining from the surface amino groups derived from APTES. The prepared sheet-NH2 showed widths of several micrometres and small thicknesses of approximately 50 nm. The pore diameter, pore volume and BET surface area of sheet-NH2 were determined by nitrogen adsorption–desorption isotherms to be 3.1 nm, 0.73 cm3 g−1 and 189.9 m2 g−1, respectively. TEM, XRD, FT-IR and TG–DTA analysis demonstrated that the sheet material had a disordered mesoporous structure and contained organic chains. The adsorptions of aqueous zinc(II and copper(II metal ions were examined and compared with amino-functionalized conventional mesoporous silica (MCM-NH2, calcined mesoporous silica sheets and silica beads with no porous structures. Notably, the sheet-NH2 exhibited the highest adsorption of both zinc and copper ions among the examined materials. In addition, the metal ion sorption equilibrium data of sheet-NH2 were fitted to the Langmuir isotherm model.

  20. Metal ion binding and function in natural and artificial small RNA enzymes from a structural perspective.

    Science.gov (United States)

    Wedekind, Joseph E

    2011-01-01

    Ribozymes are often perceived as part of an antiquated catalytic arsenal hearkening back to a pre-biotic RNA World that was eventually supplanted by proteins. However, recent genome-wide searches have revealed a plethora of new catalytic RNA motifs that appear to be variations on well-known themes. This suggests that ribozymes have continued to evolve in order to fulfill specific, RNA-essential biological niches. Although such ribozymes are small and catalyze one-step phosphodiester-bond scission reactions, ongoing structure and function analyses at the lab bench have demonstrated that RNA has the capacity for a diverse number of reactions such as carbon-carbon bond formation, and tRNA aminoacylation. Here we describe the fundamental structure and metal binding properties of four naturally occurring RNA enzymes: the hammerhead, hairpin, hepatitis delta virus, and glmS metabolite sensing ribozyme. In addition, we discuss the fold and ion coordination of three artificial ribozymes developed to probe the boundaries of RNA catalysis; these include the leadzyme, the flexizyme, and the Diels-Alder ribozyme. Our approach is to relate structure to function with the knowledge of ideal metal-ion coordination geometry that we have derived herein from surveys of high-resolution small molecule structures. An emergent theme is that natural and artificial ribozymes that catalyze single-step reactions often possess a pre-formed active site. Multivalent ions facilitate RNA active site formation, but can also provide Lewis acid functionality that is necessary for catalysis. When metal ion binding isn't possible, ribozymes make due by ionizing their bases, or by recruiting cofactors that augment their chemical functionality.

  1. Metal salts for molecular ion yield enhancement in organic secondary ion mass spectrometry: a critical assessment.

    Science.gov (United States)

    Delcorte, A; Bertrand, P

    2005-04-01

    In a search for molecular ion signal enhancement in organic SIMS, the efficiency of a series of organic and inorganic salts for molecular cationization has been tested using a panel of nonvolatile molecules with very different chemical characteristics (leucine enkephalin, Irganox 1010, tetraphenylnaphthalene, polystyrene). The compounds used for cationization include alkali bromide and group Ib metal salts (XBr with X = Li, Na, K; CF3CO2Ag; AgNO3; [CH3COCH=C(O-)CH3]2Cu; AuCl3). Alkali ions, very good for polar molecule cationization, prove to be of limited interest for nonpolar molecules such as polystyrene. Silver trifluoroacetate displays excellent results for all the considered molecules, except for leucine enkephalin (which might be due to the use of different solvents for the analyte and the salt). Instead, silver nitrate mixed with leucine enkephalin in an ethanol solution provides intense molecular signals. The influence of the respective concentrations of analyte and salt in solution, of the silver trifluoroacetate solution stability, and of the sample microstructure on the secondary ion intensities are also investigated. The results of other combinations of analyte and salts are reported. Finally, the use of salts is critically compared to other sample preparation procedures previously proposed for SIMS analysis of large organic molecules.

  2. Novel additives for the separation of organic acids by ion-pair chromatography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper proposes the use of novel surfactant additives for the separation of organic acids by ion-pair chromatography and studies the influences of surfactants on the chromatographic separation behaviors.Researches have been carried out on both silica gel matrix and polymer supporters in order to compare the two ordinary kinds of stationary phases,and the phenomenon is similar. Separation is based on differences in the stabilities of analyte-additive complexes in solution.Retention times of analytes c...

  3. Multidiagnostics analysis of ion dynamics in ultrafast laser ablation of metals over a large fluence range

    Energy Technology Data Exchange (ETDEWEB)

    Anoop, K. K.; Polek, M. P.; Bruzzese, R.; Amoruso, S.; Harilal, Sivanandan S.

    2015-02-28

    The ions dynamics in ultrafast laser ablation of metals is studied over a fluence range spanning from the ablation threshold up to ~75 J/cm2 by means of three established diagnostic techniques. Langmuir probe, Faraday cup and spectrally resolved ICCD imaging simultaneously monitor the laser-produced plasma ions produced during ultrafast laser ablation of a copper target. The fluence dependence of ion yield is analyzed observing the occurrence of three different regimes. Moreover, the specific ion yield shows a maximum at about 4-5 J/cm2, followed by a gradual reduction and a transition to a high-fluence regime above ~50 J/cm2. The fluence variation of the copper ions angular distribution is also analyzed, observing a gradual increase of forward peaking of Cu ions for fluences up to ~10 J/cm2. Then, a broader ion component is observed at larger angles for fluences larger than ~10 J/cm2. Finally, an experimental characterization of the ions angular distribution for several metallic targets (Mg, Al, Cr, Fe, Cu, and W) is carried out at a relatively high fluence of ~66 J/cm2. Interestingly, the ion emission from the volatile metals show a narrow forward peaked distribution and a high peak ion yield compared to the refractory metals. Moreover, the width of ion angular distributions presents a striking correlation with the peak ion yield.

  4. 3D Metal Printing - Additive Manufacturing Technologies for Frameworks of Implant-Borne Fixed Dental Prosthesis.

    Science.gov (United States)

    Revilla León, M; Klemm, I M; García-Arranz, J; Özcan, M

    2017-09-01

    An edentulous patient was rehabilitated with maxillary metal-ceramic and mandibular metal-resin implant-supported fixed dental prosthesis (FDP). Metal frameworks of the FDPs were fabricated using 3D additive manufacturing technologies utilizing selective laser melting (SLM) and electron beam melting (EBM) processes. Both SLM and EBM technologies were employed in combination with computer numerical control (CNC) post-machining at the implant interface. This report highlights the technical and clinical protocol for fabrication of FDPs using SLM and EBM additive technologies. Copyright© 2017 Dennis Barber Ltd.

  5. Ion-selective electrodes with solid contact for heavy metals determination

    Directory of Open Access Journals (Sweden)

    Wardak C.

    2013-04-01

    Full Text Available Potentiometric properties of ion-selective electrodes with solid contact for lead, cadmium and zinc determination were investigated. The ionic liquids (ILs alkyl methyl imidazolium chlorides are used as lipophilic ionic additive to the membrane phase and as transducer media. The basic analytical parameters of the studied electrodes, such as the slope characteristic, the detection limit, response time, lifetime, selectivity coefficients against various inorganic cations as well as the dependence of the electrodes potential on pH were determined. The obtained electrode are characterized by good analytical parameters: theoretical characteristic slope, low detection limit, short response time and very long lifetime. The electrodes was successfully applied to the direct determination of lead, cadmium and zinc ions in waste water samples. The results obtained indicate that the electrodes provide a good alternative for the determination of these heavy metals in real samples.

  6. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    Science.gov (United States)

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  7. Nanometer structure and conductor mechanism of polymer modified by metal ion implantation

    Institute of Scientific and Technical Information of China (English)

    吴瑜光; 张通和; 张燕文; 张荟星; 张孝吉; 周固

    2001-01-01

    Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implanta-tion with a dose ranging from 1 × l016 to 2 x 1017 ions/cm2 using a metal vapor vacuum arc (MEVVA)source. The electrical properties of PET have been improved by metal ion implantation. The resistivityof implanted PET decreased obviously with an increase in ion dose. The results show that the conduc-tive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to un-derstant the mechanism of electrical conduction, the structures of implanted layer were observed in de-tail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallicparticles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 x 1017 ions/cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 x 1017ions/cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealedconducting mechanism evolution, lt is believed that the change would result in an improvement of theconductive properties. The conducting mechanism will be changed with increasing metal ion dose.

  8. Heterocyclic ring based colorimetric and fluorescent chemosensor for transition metal ions in an aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Boobalan, Maria susai [Department of Chemistry, St. Joseph' s College (Autonomous), Tiruchirappalli 620002 (India); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2015-02-15

    Heterocyclic ring based R1–R3 have been synthesized from the simple condensation method. R1–R3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R1–R3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R1–R3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R1 and R2 were also successfully demonstrated as a fluorescent probe for detecting Cu{sup 2+} ions in living cells. - highlights: • R1–R3 act as colorimetric and fluorescent sensors for metal ions. • Receptors (R1–R3) detect Cu{sup 2+} ions in aqueous solution at nanomolar levels. • R1 and R2 act as a fluorescent probe for detecting Cu{sup 2+} ions in living cells.

  9. Redox-inactive metal ions promoted the catalytic reactivity of non-heme manganese complexes towards oxygen atom transfer.

    Science.gov (United States)

    Choe, Cholho; Yang, Ling; Lv, Zhanao; Mo, Wanling; Chen, Zhuqi; Li, Guangxin; Yin, Guochuan

    2015-05-21

    Redox-inactive metal ions can modulate the reactivity of redox-active metal ions in a variety of biological and chemical oxidations. Many synthetic models have been developed to help address the elusive roles of these redox-inactive metal ions. Using a non-heme manganese(II) complex as the model, the influence of redox-inactive metal ions as a Lewis acid on its catalytic efficiency in oxygen atom transfer was investigated. In the absence of redox-inactive metal ions, the manganese(II) catalyst is very sluggish, for example, in cyclooctene epoxidation, providing only 9.9% conversion with 4.1% yield of epoxide. However, addition of 2 equiv. of Al(3+) to the manganese(II) catalyst sharply improves the epoxidation, providing up to 97.8% conversion with 91.4% yield of epoxide. EPR studies of the manganese(II) catalyst in the presence of an oxidant reveal a 16-line hyperfine structure centered at g = 2.0, clearly indicating the formation of a mixed valent di-μ-oxo-bridged diamond core, Mn(III)-(μ-O)2-Mn(IV). The presence of a Lewis acid like Al(3+) causes the dissociation of this diamond Mn(III)-(μ-O)2-Mn(IV) core to form monomeric manganese(iv) species which is responsible for improved epoxidation efficiency. This promotional effect has also been observed in other manganese complexes bearing various non-heme ligands. The findings presented here have provided a promising strategy to explore the catalytic reactivity of some di-μ-oxo-bridged complexes by adding non-redox metal ions to in situ dissociate those dimeric cores and may also provide clues to understand the mechanism of methane monooxygenase which has a similar diiron diamond core as the intermediate.

  10. Bioleaching of valuable metals from spent lithium-ion mobile phone batteries using Aspergillus niger

    Science.gov (United States)

    Horeh, N. Bahaloo; Mousavi, S. M.; Shojaosadati, S. A.

    2016-07-01

    In this paper, a bio-hydrometallurgical route based on fungal activity of Aspergillus niger was evaluated for the detoxification and recovery of Cu, Li, Mn, Al, Co and Ni metals from spent lithium-ion phone mobile batteries under various conditions (one-step, two-step and spent medium bioleaching). The maximum recovery efficiency of 100% for Cu, 95% for Li, 70% for Mn, 65% for Al, 45% for Co, and 38% for Ni was obtained at a pulp density of 1% in spent medium bioleaching. The HPLC results indicated that citric acid in comparison with other detected organic acids (gluconic, oxalic and malic acid) had an important role in the effectiveness of bioleaching using A. niger. The results of FTIR, XRD and FE-SEM analysis of battery powder before and after bioleaching process confirmed that the fungal activities were quite effective. In addition, bioleaching achieved higher removal efficiency for heavy metals than the chemical leaching. This research demonstrated the great potential of bio-hydrometallurgical route to recover heavy metals from spent lithium-ion mobile phone batteries.

  11. Enhanced Mixture Separations of Metal Adducted Tetrasaccharides Using Frequency Encoded Ion Mobility Separations and Tandem Mass Spectrometry

    Science.gov (United States)

    Morrison, Kelsey A.; Bendiak, Brad K.; Clowers, Brian H.

    2016-10-01

    Using five isomeric tetrasaccharides in combination with seven multivalent metals, the impact on mobility separations and resulting CID spectra were examined using a hybrid ion mobility atmospheric pressure drift tube system coupled with a linear ion trap. By enhancing the duty cycle of the drift tube system using a linearly chirped frequency, the collision-induced dissociation spectra were encoded in the mobility domain according to the drift times of each glycan isomer precursor. Differential fragmentation patterns correlated with precursor drift times ensured direct assignment of fragments with precursor structure whether as individual standards or in a mixture of isomers. In addition to certain metal ions providing higher degrees of separation than others, in select cases more than one arrival time distribution was observed for a single pure carbohydrate isomer. These observations suggest the existence of alternative coordination sites within a single monomeric species, but more interesting was the observation of different fragmentation ion yields for carbohydrate dimers formed through metal adduction. Positive-ion data were also compared with negative-ion species, where dimer formation did not occur and single peaks were observed for each isomeric tetrasaccharide-alditol. This enhanced analytical power has implications not only for carbohydrate molecules but also for a wide variety of complex mixtures of molecules where dissociation spectra may potentially be derived from combinations of monomeric, homodimeric, and heterodimeric species having identical nominal m/z values.

  12. Metal hydrides used as negative electrode materials for Li-ion batteries

    Science.gov (United States)

    Sartori, Sabrina; Cuevas, Fermin; Latroche, Michel

    2016-02-01

    Energy is a key issue for future generation. Researches are conducted worldwide to develop new efficient means for energy conversion and storage. Electrochemical storage is foreseen as an efficient way to handle intermittent renewable energy production. The most advanced batteries are nowadays based on lithium-ion technology though their specific capacities should be significantly increased to bring solution to mass storage. Conversion reactions are one way to step forward larger capacities at the anode. We here review the possibility to use metallic or complex hydrides as negative electrode using conversion reaction of hydride with lithium. Moreover, promising alloying of lithium with the metallic species might provide additional reversible capacities. Both binary and ternary systems are reviewed and results are compared in the frame of the electrochemical application.

  13. Photochromic Terbium Phosphonates with Photomodulated Luminescence and Metal Ion Sensitive Detection.

    Science.gov (United States)

    Yang, Weiting; Tian, Hong-Rui; Li, Jian-Ping; Hui, Yuan-Feng; He, Xiang; Li, Jiyang; Dang, Song; Xie, Zhigang; Sun, Zhong-Ming

    2016-10-17

    Rational selection and modification of rare earth metal centers and photoactive organic linkers enables designable multiphotofunctionality to come to fruition in new hybrid coordination polymer materials. By using a viologen-functionalized diphosphonate linker, two terbium phosphonate compounds (Tb-1 and Tb-2) have been constructed, which display reversible photochromic reactions in response to UV light and soft X-ray irradiation. In addition, the photo-induced electron-transfer reaction can modulate the luminescent emission to thus realize photoluminescence switching behavior. Furthermore, both terbium phosphonates can serve as highly sensitive sensors to probe Cu(2+) in solution through their luminescence. Thus, they represent the first photochromic examples of lanthanide phosphonate-based materials with photomodulated luminescence and sensitive detection of metal ions.

  14. Effect of Some Metal Ion Dopants on Electrochemical Properties of Ni(OH)2 Film Electrode

    Institute of Scientific and Technical Information of China (English)

    ZHANG Heng-bin; LIU Han-san; CAO Xue-jing; SUN Chia-chung

    2003-01-01

    The Ni(OH)2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition. The electrode reaction reversibility, the difficult extent of oxygen evolution, the proton diffusion coefficient, the discharge potential of middle value and the active material utilization of the Ni(OH)2 film electrode were compared with those of the ones doped with the metal ions by means of cyclic voltammetry, potential step and constant current charge-discharge experiments. It was found that Ca2+, Co2+, Cd2+, Al3+ etc. have obviously positive effect.

  15. Measurement of free heavy metal ion concentrations in soils using Donnan membrane technique

    Institute of Scientific and Technical Information of China (English)

    YI Li; HONG Yetang; WENG Liping; ZHU Yongxuan

    2005-01-01

    In natural systems heavy metals are present in very low concentrations (less than micro-molar), so precise measurement of the free metal ions is difficult. Recently, a new method has been developed called the Donnan membrane technique (DMT). Several heavy metals could be measured simultaneously using this method. Furthermore, all the metals did not interfere with each other, and the balance between the measured system and the surrounding condition could not be disturbed. Improvements were made according to the internal condition. The free heavy metal ion concentrations were measured in different systems using the improved method, and satisfied results have been obtained.

  16. Benchmarking a computational design method for the incorporation of metal ion-binding sites at symmetric protein interfaces.

    Science.gov (United States)

    Hansen, William A; Khare, Sagar D

    2017-08-01

    The design of novel metal-ion binding sites along symmetric axes in protein oligomers could provide new avenues for metalloenzyme design, construction of protein-based nanomaterials and novel ion transport systems. Here, we describe a computational design method, symmetric protein recursive ion-cofactor sampling (SyPRIS), for locating constellations of backbone positions within oligomeric protein structures that are capable of supporting desired symmetrically coordinated metal ion(s) chelated by sidechains (chelant model). Using SyPRIS on a curated benchmark set of protein structures with symmetric metal binding sites, we found high recovery of native metal coordinating rotamers: in 65 of the 67 (97.0%) cases, native rotamers featured in the best scoring model while in the remaining cases native rotamers were found within the top three scoring models. In a second test, chelant models were crossmatched against protein structures with identical cyclic symmetry. In addition to recovering all native placements, 10.4% (8939/86013) of the non-native placements, had acceptable geometric compatibility scores. Discrimination between native and non-native metal site placements was further enhanced upon constrained energy minimization using the Rosetta energy function. Upon sequence design of the surrounding first-shell residues, we found further stabilization of native placements and a small but significant (1.7%) number of non-native placement-based sites with favorable Rosetta energies, indicating their designability in existing protein interfaces. The generality of the SyPRIS approach allows design of novel symmetric metal sites including with non-natural amino acid sidechains, and should enable the predictive incorporation of a variety of metal-containing cofactors at symmetric protein interfaces. © 2017 The Protein Society.

  17. Metal-on-metal bearings in total hip arthroplasties : Influence of cobalt chromium ions on bacterial growth and biofilm formation

    NARCIS (Netherlands)

    Hosman, Anton H.; van der Mei, Henny C.; Bulstra, Sjoerd K.; Busscher, Henk J.; Neut, Danielle

    2009-01-01

    Metal-on-metal (MOM) bearings involving cobalt-chromium (Co-Cr) alloys in total hip arthroplasties are becoming more and more popular due to their low wear. Consequences of corrosion products of Co-Cr alloys are for the most part unclear, and the influence of cobalt and chromium ions on biofilm form

  18. Effect of vermicomposting on concentration and speciation of heavy metals in sewage sludge with additive materials.

    Science.gov (United States)

    He, Xin; Zhang, Yaxin; Shen, Maocai; Zeng, Guangming; Zhou, Mucen; Li, Meirong

    2016-10-01

    The aim of this work was to evaluate the total content and speciation of heavy metals (As, Cr, Cd, Cu, Fe, Mn, Ni, Pb and Zn) during vermicomposting of sewage sludge by Eisenia fetida earthworm with different additive materials (soil, straw, fly ash and sawdust). Results showed that the pH, total organic carbon were reduced, while the electric conductivity and germination index increased after a combined composting - vermicomposting process. The addition of bulking agents accelerated the stabilization of sludge and eliminated its toxicity. The total heavy metals after vermicomposting in 10 scenarios were lowered as compared with the initial values and the control without amendment. BCR sequential extraction indicated that vermicomposting significantly decreased the mobility of all heavy metals by increasing the residual fractions. The activity of earthworms and appropriate addition of amendment materials played a positive role in sequestering heavy metals during the treatment of sewage sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Phosphazene Based Additives for Improvement of Safety and Battery Lifetimes in Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Mason K Harrup; Kevin L Gering; Harry W Rollins; Sergiy V Sazhin; Michael T Benson; David K Jamison; Christopher J Michelbacher

    2011-10-01

    There need to be significant improvements made in lithium-ion battery technology, principally in the areas of safety and useful lifetimes to truly enable widespread adoption of large format batteries for the electrification of the light transportation fleet. In order to effect the transition to lithium ion technology in a timely fashion, one promising next step is through improvements to the electrolyte in the form of novel additives that simultaneously improve safety and useful lifetimes without impairing performance characteristics over wide temperature and cycle duty ranges. Recent efforts in our laboratory have been focused on the development of such additives with all the requisite properties enumerated above. We present the results of the study of novel phosphazene based electrolytes additives.

  20. Catalytic potential of selected metal ions for bioleaching, and potential techno-economic and environmental issues: A critical review.

    Science.gov (United States)

    Pathak, Ashish; Morrison, Liam; Healy, Mark Gerard

    2017-04-01

    Bioleaching is considered to be a low-cost, eco-friendly technique for leaching valuable metals from a variety of matrixes. However, the inherent slow dissolution kinetics and low metal leaching yields have restricted its wider commercial applicability. Recent advancements in bio-hydrometallurgy have suggested that these critical issues can be successfully alleviated through the addition of a catalyst. The catalyzing properties of a variety of metals ions (Ag(+), Hg(++), Bi(+++), Cu(++), Co(++) etc.) during bioleaching have been successfully demonstrated. In this article, the role and mechanisms of these metal species in catalyzing bioleaching from different minerals (chalcopyrite, complex sulfides, etc.) and waste materials (spent batteries) are reviewed, techno-economic and environmental challenges associated with the use of metals ions as catalysts are identified, and future prospectives are discussed. Based on the analysis, it is suggested that metal ion-catalyzed bioleaching will play a key role in the development of future industrial bio-hydrometallurgical processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Study of argon additive in a beam injection type negative ion source using VUV emission spectroscopy

    OpenAIRE

    Nakada, Naoki; Fukumasa, Osamu

    2006-01-01

    Effects of Ar addition are studied by using a beam injection type negative ion source. With adding Ar, I_ increases at low base H_2 pressure. At high base H_2 pressure, however, I_ decreases. VUV emission intensities also decrease at high base pressure. In other words, Ar addition is adverse effect for production of H_2 (v''). Therefore, decrease in I_ is caused by decrease in H_2 (v''). In D_2 plasmas, variation patterns of plasma parameters and VUV intensities by Ar addition are nearly the ...

  2. New electrolytes and electrolyte additives to improve the low temperature performance of lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiao-Qing

    2008-08-31

    In this program, two different approaches were undertaken to improve the role of electrolyte at low temperature performance - through the improvement in (i) ionic conductivity and (ii) interfacial behavior. Several different types of electrolytes were prepared to examine the feasibil.ity of using these new electrolytes in rechargeable lithium-ion cells in the temperature range of +40°C to -40°C. The feasibility studies include (a) conductivity measurements of the electrolytes, (b) impedance measurements of lithium-ion cells using the screened electrolytes with di.fferent electrochemical history such as [(i) fresh cells prior to formation cycles, (ii) after first charge, and (iii) after first discharge], (c) electrical performance of the cells at room temperatures, and (d) charge discharge behavior at various low temperatures. Among the different types of electrolytes investigated in Phase I and Phase II of this SBIR project, carbonate-based LiPF6 electrolytes with the proposed additives and the low viscous ester as a third component to the carbonate-based LiPF6 electrolytes show promising results at low temperatures. The latter electrolytes deliver over 80% of room temperature capacity at -20{degrees}C when the lithium-ion cells containing these electrolytes were charged at -20 °C. Also, there was no lithium plating when the lithium­-ion cells using C-C composite anode and LiPF{sub 6} in EC/EMC/MP electrolyte were charged at -20{degrees}C at C/5 rate. The studies of ionic conductivity and AC impedance of these new electrolytes, as well as the charge discharge characteristics of lithium-ion cells using these new electrolytes at various low temperatures provide new findings: The reduced capacity and power capability, as well as the problem of lithium plating at low temperatures charging of lithium-ion cells are primarily due to slow the lithium-ion intercalation/de-intercalation kinetics in the carbon structure.

  3. Metal ions removal from polluted waters by sorption onto exhausted coffee waste. Application to metal finishing industries wastewater treatment

    OpenAIRE

    Liu, Chang

    2014-01-01

    A new technology for Cr(VI) and divalent metal ions removal based on metal sorption onto exhausted coffee waste has been developed. Physical and chemical characterization of exhausted coffee waste was explored as well as the role of structural and non structural compounds of the waste in metal ions sorption. Kinetics of Cr(VI) sorption from binary mixtures containing different Cr(VI) and Cu(II) molar ratios were carried out in a batch reactor. A synergistic effect of Cu(II) in Cr(VI) reductio...

  4. A new strategy to stabilize oxytocin in aqueous solutions : I. The effects of divalent metal ions and citrate buffer

    NARCIS (Netherlands)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J. M.; Hinrichs, Wouter L. J.; Frijlink, Henderik W.

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The

  5. A new strategy to stabilize oxytocin in aqueous solutions : I. The effects of divalent metal ions and citrate buffer

    NARCIS (Netherlands)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J. M.; Hinrichs, Wouter L. J.; Frijlink, Henderik W.

    2011-01-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The effec

  6. Effects of lability of metal complex on free ion measurement using DMT.

    Science.gov (United States)

    Weng, Liping; Van Riemsdijk, Willem H; Temminghoff, Erwin J M

    2010-04-01

    Very low concentrations of free metal ion in natural samples can be measured using the Donnan membrane technique (DMT) based on ion transport kinetics. In this paper, the possible effects of slow dissociation of metal complexes on the interpretation of kinetic DMT are investigated both theoretically and experimentally. The expressions of the lability parameter, Lgrangian , were derived for DMT. Analysis of new experimental studies using synthetic solution containing NTA as the ligand and Cu(2+) ions shows that when the ionic strength is low (DMT measurement. In natural waters, dissolved organic matter (DOM) is the most important source of ligands that complex metals. By comparing the fraction of labile species measured using other dynamic sensors (DGT, GIME) in several freshwaters, it is concluded that in most waters ion transport in DMT is controlled by diffusion in the membrane. Only in very soft waters (DMT. In this case, neglecting this effect may lead to an underestimation of the free metal ion concentration measured.

  7. 4-Vinyl-1,3-Dioxolane-2-One as an Additive for Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall; Bugga, Ratnakumar

    2006-01-01

    Electrolyte additive 4-vinyl-1,3-dioxolane-2-one has been found to be promising for rechargeable lithium-ion electrochemical cells. This and other additives, along with advanced electrolytes comprising solutions of LiPF6 in various mixtures of carbonate solvents, have been investigated in a continuing effort to improve the performances of rechargeable lithium-ion electrochemical cells, especially at low temperatures. In contrast to work by other researchers who have investigated the use of this additive to improve the high-temperature resilience of Li-ion cells, the current work involves the incorporation of 4-vinyl-1,3-dioxolane-2-one into quaternary carbonate electrolyte mixtures, previously optimized for low-temperature applications, resulting in improved low-temperature performance. The benefit afforded by 4-vinyl-1,3- dioxolane-2-one can be better understood in the light of relevant information from a number of prior NASA Tech Briefs articles about electrolytes and additives for such cells. To recapitulate: The loss of performance with decreasing temperature is attributable largely to a decrease of ionic conductivity and the increase in viscosity of the electrolyte. What is needed to extend the lower limit of operating temperature is a stable electrolyte solution with relatively small lowtemperature viscosity, a large electric permittivity, adequate coordination behavior, and appropriate ranges of solubilities of liquid and salt constituents. Whether the anode is made of graphitic or non-graphitic carbon, a film on the surface of the anode acts as a solid/electrolyte interface (SEI), the nature of which is critical to low-temperature performance. Desirably, the surface film should exert a chemically protective (passivating) effect on both the anode and the electrolyte, yet should remain conductive to lithium ions to facilitate intercalation and de-intercalation of the ions into and out of the carbon during discharging and charging, respectively. The additives

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

    Science.gov (United States)

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

    2013-11-18

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

  9. Heavy-Ion-Induced Electronic Desorption of Gas from Metals

    CERN Document Server

    Molvik, A W; Mahner, E; Kireeff Covo, M; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Krämer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2007-01-01

    During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dEe/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  10. Heavy-ion induced electronic desorption of gas from metals

    Energy Technology Data Exchange (ETDEWEB)

    Molvik, A W; Kollmus, H; Mahner, E; Covo, M K; Bellachioma, M C; Bender, M; Bieniosek, F M; Hedlund, E; Kramer, A; Kwan, J; Malyshev, O B; Prost, L; Seidl, P A; Westenskow, G; Westerberg, L

    2006-12-19

    During heavy ion operation in several particle accelerators world-wide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion induced gas desorption scales with the electronic energy loss (dE{sub e}/d/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

  11. Metal-ion effects on the polarization of metal-bound water and infrared vibrational modes of the coordinated metal center of Mycobacterium tuberculosis pyrazinamidase via quantum mechanical calculations.

    Science.gov (United States)

    Salazar-Salinas, Karim; Baldera-Aguayo, Pedro A; Encomendero-Risco, Jimy J; Orihuela, Melvin; Sheen, Patricia; Seminario, Jorge M; Zimic, Mirko

    2014-08-28

    Mycobacterium tuberculosis pyrazinamidase (PZAse) is a key enzyme to activate the pro-drug pyrazinamide (PZA). PZAse is a metalloenzyme that coordinates in vitro different divalent metal cofactors in the metal coordination site (MCS). Several metals including Co(2+), Mn(2+), and Zn(2+) are able to reactivate the metal-depleted PZAse in vitro. We use quantum mechanical calculations to investigate the Zn(2+), Fe(2+), and Mn(2+) metal cofactor effects on the local MCS structure, metal-ligand or metal-residue binding energy, and charge distribution. Results suggest that the major metal-dependent changes occur in the metal-ligand binding energy and charge distribution. Zn(2+) shows the highest binding energy to the ligands (residues). In addition, Zn(2+) and Mn(2+) within the PZAse MCS highly polarize the O-H bond of coordinated water molecules in comparison with Fe(2+). This suggests that the coordination of Zn(2+) or Mn(2+) to the PZAse protein facilitates the deprotonation of coordinated water to generate a nucleophile for catalysis as in carboxypeptidase A. Because metal ion binding is relevant to enzymatic reaction, identification of the metal binding event is important. The infrared vibrational mode shift of the C═Nε (His) bond from the M. tuberculosis MCS is the best IR probe to metal complexation.

  12. Heavy metal ion uptake properties of polystyrene-supported chelating polymer resins

    Indian Academy of Sciences (India)

    A Ravikumar Reddy; K Hussain Reddy

    2003-06-01

    Metal ion uptake properties of polystyrene-supported chelating polymer resins functionalized with (i) glycine, (ii) hydroxy benzoic acid, (iii) Schiff base and (iv) diethanol amine have been investigated. The effects of pH, time and initial concentration on the uptake of metal ions have been studied. The uptake of metal ion depends on pH. The resins are more selective at pH 10 for Pb(II) and Hg(II), whereas at pH 6 they are found to be Cd(II) and Cr(VI) selective. Metal ion uptake properties of resins follow Freundlich’s equation. The resins are recyclable and are therefore employed for the removal of heavy metal pollutants from industrial waste water.

  13. Electrochemical, optical and metal ion sensing properties of dithizone derivatised electrodes

    CERN Document Server

    Mirkhalaf, F

    1998-01-01

    studied. Possible applications of these modified electrodes with potential control in metal ion detection are described. The electrochemical and SPR responses for the metal ion sensing by the monolayer films were compared with those of polymer films containing the same ligand. Derivatisation of electrode surfaces with ultra-thin films of organic molecules has been extensively studied for many applications in recent years. The present study is based on a new approach in the preparation and use of these electrodes for metal ion sensing. Modification of electrode surfaces with a ligand specific to heavy metal ions has been described. A new derivative of dithizone (DDz) and its secondary metal complexes have been synthesised and attached onto indium tin oxide (ITO) and gold electrodes. This was achieved by covalent bonding between carboxyl groups in DDz and terminal amine groups of molecules self-assembled on the electrode surfaces. These monolayer films were characterised by cyclic voltammetry, by in situ and ex...

  14. Adsorption Mechanisms of Heavy Metal Ions from Drinking Water by Weakly Basic Anion Exchange Resins

    Institute of Scientific and Technical Information of China (English)

    赵璇; 何仕均; 杨磊

    2002-01-01

    Heavy metal micro-contaminants can be removed from water sources technologies. Weakly basic anion exchange resins offer the best ability to remove trace amounts of heavy metals with high selectivity. This paper discusses how weakly basic resins adsorb heavy metals using two different approaches. The removal of mercury, cadmium, and lead ions is based on the fundamental theory of coordination chemistry. The mechanism is not ion exchange but extractive adsorption of heavy metal salts. However, the marked preferential adsorption of chromate by weakly basic anion exchange can be explained using the traditional theory of ion exchange. A lab-scale study produced positive results for the removal of trace amounts of heavy metal ions from drinking water.

  15. Studies on the Transition Metal Ion Induced Fluorescence Enhancement of 1,8-Naphthalimide Derivatives

    Institute of Scientific and Technical Information of China (English)

    WEN,Guo-Tao; ZHU,Man-Zhou; WANG,Zhuo; MENG,Xiang-Ming; HU,Hui-Yuan; GUO,Qing-Xiang

    2006-01-01

    Two fluorosensor systems have been designed and synthesized with their photophysical properties and fluorescence responses toward the transition metal ions studied. The fluorosensor was composed of 1,8-naphthalimide and 4-chloro-1,8-naphthalimide as fluorophore respectively, an amino moiety as the receptor and a hydrocarbon chain as the spacer to link the fluorophore and receptor. Fluorescence intensity of these systems is very weak due to the process of the efficient intramolecular photoinduced electron transfer (PET) in the absence of metal ions. Titration of the transition metal ions can switch on the fluorescence immediately. The intensity of released fluorescence is even higher than the expected from the consideration of the PET in these systems. It may be rationalized that the receptor bound to transition metal ions and the solvation of the fluorophore by the water molecules from the hydrated transition metal salts, may significantly cause fluorescence enhancement.

  16. Metal-Ion Metathesis and Properties of Triarylboron-Functionalized Metal-Organic Frameworks.

    Science.gov (United States)

    Wang, Xiaoqing; Zhang, Liangliang; Yang, Jie; Dai, Fangna; Wang, Rongming; Sun, Daofeng

    2015-07-01

    An anionic metal-organic framework, H3[(Mn4Cl)3L8]⋅30H2O⋅2.5 DMF⋅5 Diox (UPC-15), was successfully prepared by the reaction of MnCl2 with tris(p-carboxylic acid)tridurylborane (H3 L) under solvothermal conditions. UPC-15 with wide-open pores (∼18.8 Å) is constructed by packing of octahedral and cuboctahedral cages, and exhibits high gas-sorption capabilities. Notably, UPC-15 shows selective adsorption of cationic dyes due to the anion framework. Moreover, the catalytic and magnetic properties were investigated, and UPC-15 can highly catalyze the cyanosilylation of aromatic aldehydes. UPC-15 exhibits the exchange of metal ions from Mn to Cu in a single-crystal-to-single-crystal manner to generate UPC-16, which could not be obtained by the direct solvothermal reaction of CuCl2 and H3L. UPC-16 exhibits similar properties for gas sorption, dye separation, and catalytic activity. However, the magnetic behaviors for UPC-15 and UPC-16 are distinct due to the metal-specific properties. Below 47 K, UPC-15 exhibits a ferromagnetic coupling but UPC-16 shows a dominant antiferromagnetic behavior.

  17. Possible Immune Regulation of Natural Killer T Cells in a Murine Model of Metal Ion-Induced Allergic Contact Dermatitis.

    Science.gov (United States)

    Kumagai, Kenichi; Horikawa, Tatsuya; Shigematsu, Hiroaki; Matsubara, Ryota; Kitaura, Kazutaka; Eguchi, Takanori; Kobayashi, Hiroshi; Nakasone, Yasunari; Sato, Koichiro; Yamada, Hiroyuki; Suzuki, Satsuki; Hamada, Yoshiki; Suzuki, Ryuji

    2016-01-12

    Metal often causes delayed-type hypersensitivity reactions, which are possibly mediated by accumulating T cells in the inflamed skin, called irritant or allergic contact dermatitis. However, accumulating T cells during development of a metal allergy are poorly characterized because a suitable animal model is unavailable. We have previously established novel murine models of metal allergy and found accumulation of both metal-specific T cells and natural killer (NK) T cells in the inflamed skin. In our novel models of metal allergy, skin hypersensitivity responses were induced through repeated sensitizations by administration of metal chloride and lipopolysaccharide into the mouse groin followed by metal chloride challenge in the footpad. These models enabled us to investigate the precise mechanisms of the immune responses of metal allergy in the inflamed skin. In this review, we summarize the immune responses in several murine models of metal allergy and describe which antigen-specific responses occur in the inflamed skin during allergic contact dermatitis in terms of the T cell receptor. In addition, we consider the immune regulation of accumulated NK T cells in metal ion-induced allergic contact dermatitis.

  18. Interaction between ATP, metal ions, glycine, and several minerals

    Science.gov (United States)

    Rishpon, J.; Ohara, P. J.; Lawless, J. G.; Lahav, N.

    1982-01-01

    Interactions between ATP, glycine and montmorillonite and kaolinite clay minerals in the presence of various metal cations are investigated. The adsorption of adenine nucleotides on clays and Al(OH)3 was measured as a function of pH, and glycine condensation was followed in the presence of ATP, ZnCl2, MgCl2 and either kaolinite or montmorillonite. The amounts of ATP and ADP adsorbed are found to decrease with increasing Ph, and to be considerably enhanced in experiments with Mg(2+)- and Zn(2+)-montmorillonite with respect to Na(+)-montmorillonite. The effects of divalent cations are less marked in kaolinite. Results for Al(OH)3 show the importance of adsorption at clay platelet edges at high pH. The decomposition of ATP during drying at high temperature is observed to be inhibited by small amounts of clay, vacuum, or Mg(2+) or Zn(2+) ions, and to be accompanied by peptide formation in the presence of glycine. Results suggest the importance of Zn(2+) and Mg(2+) in chemical evolution.

  19. Photoluminescence of ZnO in metal ion exchanged zeolite Y.

    Science.gov (United States)

    So, Soo Jeong; Kim, Hee Jin; Cha, Du Hwan; Han, Chong Soo

    2011-01-01

    The photoluminescence of nano-sized ZnO in metal-ion-exchanged zeolite Y (ZnO/M-FAU, M = Na, Ca, Er) was investigated. ZnO/M-FAU was prepared by exposing Er(3+)- or Ca(2+)-exchanged Na-FAU to Zn vapor and to air at 723 K. The ZnO formation in the M-FAU showed a change in intensity in the (220), (311) and (331) lines, but no indication of ZnO peaks. In the EDXS and ICPAES analyses, it was found that the molar ratio of Zn/Si was linearly related to the exchanged amount of metal ions, and that the slope of the Zn/Si to the metal/Si was in the order of ZnO/Na-FAU FAU FAU. In the photoluminescence spectra of all the ZnO/M-FAU samples, peaks were observed at around 380 nm (3.2 eV) and 530 nm (2.5 eV) of ZnO. In ZnO/ErNa-FAU sample, the reabsorption of Er3+ at 520 nm and its emission at 650 nm were observed at the 530 nm peak of ZnO, which can be explained in terms of the interaction of ZnO with Er3+ in the FAU. In the case of ZnO/CaNa-FAU, the peak at around 380 nm was broaden to a longer wavelength, which is supposed to have been caused by emission peak of (CaO)x(ZnO)y. In addition, there were some indications of interaction between Na+ ZnO in ZnO/Na-FAU and the ZnO that was doped with Na+. From the result, it is suggested that ZnO particles were formed in the cavities that interacted with the ions in the zeolites.

  20. Determination of metal ions by fluorescence anisotropy exhibits a broad dynamic range

    Science.gov (United States)

    Thompson, Richard B.; Maliwal, Badri P.; Fierke, Carol A.

    1998-05-01

    Recently, we have shown that metal ions free in solution may be determined at low levels by fluorescence anisotropy (polarization) measurements. Anisotropy measurements enjoy the advantages of wavelength ratiometric techniques for determining metal ions such as calcium, because anisotropy measurements are ratiometric as well. Furthermore, fluorescence anisotropy may be imaged in the microscope. An advantage of anisotropy not demonstrated for wavelength ratiometric approaches using indicators such as Fura-2 and Indo-1 is that under favorable circumstances anisotropy-based determinations exhibit a much broader dynamic range in metal ion concentration. Determinations of free Zn(II) in the picomolar range are demonstrated.

  1. Metal ion binding with carbon nanotubes and graphene: Effect of chirality and curvature

    Science.gov (United States)

    Umadevi, Deivasigamani; Sastry, G. Narahari

    2012-10-01

    First principles calculations have been used to comprehensively study the binding of a series alkali (Li+, Na+, K+) and alkaline earth (Be2+, Mg2+, Ca2+) metal ions with carbon nanotubes (CNTs) and graphene. It is interesting to note that the mono-cationic systems prefer binding to armchair CNTs over zigzag CNTs, while the preference for the di-cationic systems is exactly opposite. We have also observed significant changes in the HOMO-LUMO energy gap of the CNTs on metal ion binding and these results indicate that the fine tuning of energy gap of the CNTs can be effected through metal ion binding.

  2. In vitro corrosion behaviour and metallic ion release of different prosthodontic alloys.

    Science.gov (United States)

    Gil, F J; Sánchez, L A; Espías, A; Planell, J A

    1999-12-01

    The corrosion resistance for six metallic alloys often used in clinical dentistry, was evaluated by measuring their polarisation resistance in an artificial saliva environment. The critical current density (icr), the passive current density (ip), the corrosion potential (Ecorr) and the critical pitting potential (Ecp), were studied. Metallic ion release from the different alloys was analysed in a saliva environment at 37 degrees C. The nickel-chromium alloy exhibited important corrosion and a high quantity of ions was released. The titanium presented a low value of ion release and a good corrosion resistance due to the passive film on the metal surface. The high gold content alloy provided the best corrosion resistance.

  3. Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Albrecht Hartmann

    Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

  4. Sono-electrochemical recovery of metal ions from their aqueous solutions.

    Science.gov (United States)

    Dong, Bingfeng; Fishgold, Asher; Lee, Paul; Runge, Keith; Deymier, Pierre; Keswani, Manish

    2016-11-15

    Metal recovery from aqueous waste streams is an important goal for recycling, agriculture and mining industries. The development of more effective methods of recovery have been of increasing interest. The most common methods for metal recovery include precipitation, electrochemical, ion exchange, flocculation/coagulation and filtration. In the current work, a sono-electrochemical technique employing sound field at megasonic frequency (500kHz or 1MHz) in conjunction with electrochemistry is evaluated for enhanced recovery of selected metal ions (palladium, lead and gallium) with different redox potentials from their aqueous solutions. The surface morphology and elemental composition of the metal deposits were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The percent recovery was found to depend on the type of metal ion and the megasonic frequency used. Palladium was recovered in its metal form, while lead and gallium were oxidized during or after the recovery process.

  5. Metal and Oxide Additives as Agents for Munitions Self-Remediation

    Science.gov (United States)

    2010-07-01

    extraneous nails and metal fragments. In addition to the amount of Fe0 amended, several key variables that may influence magnetic recovery of explosives...Amonette, J. E., Szecsody, J. E., Istok, J. D., and Humphrey, M. D. (2000). Creation of a subsurface permeable treatment zone for aqueous chromate...152 pp.. 50 Tratnyek, P.G., M.M. Scherer, T.L. Johnson, L.J. Matheson (2003). Permeable reactive barriers of iron and other zero-valent metals, Chap

  6. Effects of soil water content and organic matter addition on the speciation and bioavailability of heavy metals.

    Science.gov (United States)

    Hernandez-Soriano, Maria C; Jimenez-Lopez, Jose C

    2012-04-15

    The mobility and bioavailability of cadmium, copper, lead and zinc were evaluated in three soils amended with different organic materials for two moisture regimes. Agricultural and reclamation activities impose fresh inputs of organic matter on soil while intensive irrigation and rainstorm increase soil waterlogging incidence. Moreover, scarcity of irrigation water has prompted the use of greywater, which contain variable concentrations of organic compounds such as anionic surfactants. Soils added with hay, maize straw or peat at 1% w/w were irrigated, at field capacity (FC) or saturated (S), with an aqueous solution of the anionic surfactant Aerosol 22 (A22), corresponding to an addition of 200 mgC/kgsoil/day. Soil solution was extracted after one month and analysed for total soluble metals, dissolved soil organic matter and UV absorbance at 254 nm. Speciation analyses were performed with WHAM VI for Cd, Cu, Pb, and Zn. For selected scenarios, metal uptake by barley was determined. Metal mobility increased for all treatments and soils (Pb>Cu>Cd≥Zn) compared to control assays. The increase was significantly correlated (psoil organic matter solubilisation for Cd (R=0.68), Cu (R=0.73) and Zn (R=0.86). Otherwise, Pb release was related to aluminium solubilisation (R=0.75), which suggests that Pb was originally co-precipitated with Al-DOC complexes in the solid phase. The effect of A22 in metal bioavailability, determined as free ion activities (FIA), was mainly controlled by soil moisture regime. For soil 3, metal bioavailability was up to 20 times lower for soil amended with hay, peat or maize compared to soil treated only with A22. When soil was treated with A22 at FC barley yield significantly decreased (psoil organic matter and formation of metal-organo complexes. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Effect of transition-metal additives on hydrogen desorption kinetics of MgH2

    Science.gov (United States)

    Roy, Anindya; Janotti, Anderson; Van de Walle, Chris G.

    2013-01-01

    Using first-principles calculations, we study the effect of transition-metal additives (Ti, Fe, Co, and Ni) on the rate of hydrogen desorption in MgH2. The presence of large concentrations of transition-metal impurities causes the Fermi level to shift according to the position of the transition-metal acceptor/donor levels in the band gap. This shift can lower the formation energy of native defects and increase their concentration. The resulting higher rates of hydrogen desorption enhance the prospect of MgH2 as a solid-state hydrogen-storage material.

  8. Catalysis by alkali and alkaline-earth metal ions in nucleophilic attack of methoxide ion on crown ethers bearing an intra-annular acetoxy group

    NARCIS (Netherlands)

    Cacciapaglia, Roberta; Lucente, Silvia; Mandolini, Luigi; Doorn, van Arie R.; Reinhoudt, David N.; Verboom, Willem

    1989-01-01

    Rates of reaction of methoxide ion with crown ethers bearing an intra-annular acetoxy group are markedly enhanced by alkali and alkaline-earth metal bromides as a result of much stronger interactions of the metal ions with transition states than with reactants. Rates of reactions of methoxide ion w

  9. Role of sodium ions in the vitrification process: glass matrix modification, slag structure depolymerization, and influence of metal immobilization.

    Science.gov (United States)

    Kuo, Yi-Ming

    2014-07-01

    This study investigates the role of Na ions, a common flux, in the vitrification process. Artificial glass systems composed of Al2O3, CaO, and SiO2 with various Na concentrations were melted at 1450 degrees C. The specimens were cooled by air cooling and water quenching and the metal mobility was evaluated using a sequential extraction procedure. The X-ray diffraction analysis and scanning electron microscopy observations showed that Na ions governed the air-cooled slag's structure. Na ions initially depolymerized CaSiO3-linked chains into CaSiO3 chains, and further cut them into shorter and nonuniform ones, making the slag structure amorphous. With even more Na ions, CaSiO3 chains were divided into single SiO4 tetrahedrons and formed Na-related crystals (Na2Ca3Si2O8 and NaAlSiO4). The phase distributions of Al, Cr, Cu Mn, and Ni showed that Na has a positive effect on the immobilization of heavy metals at suitable concentrations, but a negative effect when in excess amounts. Implications: Vitrification has been widely used to treat hazardous materials. The Na-bearing additives were often used as a flux to improve the melting process. This study described the role of Na played in the vitrification process. The Na ions acted as glass modifier and depolymerize the chain structure of slag. With adequate addition amount of Na ions, the immobilization of heavy metals was improved. The results provided much information about the crystalline phase variation, metal mobility, and surface characteristics while Na serves as a flux.

  10. Divalent metal ion differentially regulates the sequential nicking reactions of the GIY-YIG homing endonuclease I-BmoI.

    Directory of Open Access Journals (Sweden)

    Benjamin P Kleinstiver

    Full Text Available Homing endonucleases are site-specific DNA endonucleases that function as mobile genetic elements by introducing double-strand breaks or nicks at defined locations. Of the major families of homing endonucleases, the modular GIY-YIG endonucleases are least understood in terms of mechanism. The GIY-YIG homing endonuclease I-BmoI generates a double-strand break by sequential nicking reactions during which the single active site of the GIY-YIG nuclease domain must undergo a substantial reorganization. Here, we show that divalent metal ion plays a significant role in regulating the two independent nicking reactions by I-BmoI. Rate constant determination for each nicking reaction revealed that limiting divalent metal ion has a greater impact on the second strand than the first strand nicking reaction. We also show that substrate mutations within the I-BmoI cleavage site can modulate the first strand nicking reaction over a 314-fold range. Additionally, in-gel DNA footprinting with mutant substrates and modeling of an I-BmoI-substrate complex suggest that amino acid contacts to a critical GC-2 base pair are required to induce a bottom-strand distortion that likely directs conformational changes for reaction progress. Collectively, our data implies mechanistic roles for divalent metal ion and substrate bases, suggesting that divalent metal ion facilitates the re-positioning of the GIY-YIG nuclease domain between sequential nicking reactions.

  11. Recycling of red muds with the extraction of metals and special additions to cement

    Science.gov (United States)

    Zinoveev, D. V.; Diubanov, V. G.; Shutova, A. V.; Ziniaeva, M. V.

    2015-01-01

    The liquid-phase reduction of iron oxides from red mud is experimentally studied. It is shown that, in addition to a metal, a slag suitable for utilization in the construction industry can be produced as a result of pyrometallurgical processing of red mud. Portland cement is shown to be produced from this slag with mineral additions and a high-aluminate expansion addition to cement.

  12. A Study on the Fixed-bed Adsorption of Heavy Metal Ions over Chitosan Bead

    Energy Technology Data Exchange (ETDEWEB)

    Chung, K.H. [Department of Petrochemical Engineering, Hanlyo University, Chonnam (Korea)

    1999-02-01

    Fixed-bed adsorption of metal ions on chitosan bead was studied to remove heavy metal ions in waste water. Chitin was extracted from crab shell and chitosan was prepared by deacetylation of the chitin. The chitosan in bead was used as an adsorbent for heavy metal ions. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual metal ion (Cu{sup 2+}, Co{sup 2+}, Ni{sup 2+}) on chitosan bead. Adsorption strength of metal ions decreased in the order of Cu{sup 2+}>Co{sup 2+}>Ni{sup 2+} ion. Breakthrough curves of single and multicomponent adsorption for metal ions were obtained from the experimental results of fixed-bed adsorption. The breakthrough curves were analyzed by simulation with fixed-bed adsorption equation based on LDFA (linear driving force approximation) adopted LAS (ideal adsorbed solution) theory which can predict multi-component adsorption isotherm from individual adsorption isotherm. The behavior of fixed bed adsorption for single and multi-component system could be nicely simulated by the equation. 22 refs., 10 figs., 2 tabs.

  13. Improving resistance welding of aluminum sheets by addition of metal powder

    DEFF Research Database (Denmark)

    Al Naimi, Ihsan K.; Al-Saadi, Moneer H.; Daws, Kasim M.

    2015-01-01

    . The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA......2024 and AA7075) are investigated for the resistance spot welding of AA1050 aluminum sheets of three different thicknesses. Microstructural and mechanical analysis demonstrates that significant improvement in weld bead morphology and strength are obtained with the addition of metal powder...

  14. Electrochemical preparation of metal microstructures on large areas of etched ion track membranes

    Science.gov (United States)

    Dobrev, D.; Vetter, J.; Angert, N.

    1999-01-01

    A microgalvanic method for metal filling of etched ion tracks in organic foils on large areas is described. The method and the used galvanic cell permit the deposition of stable standing individual metal whiskers with high aspect ratio and a density of 10 5-10 8 per cm 2 on an area of 12.5 cm 2. The method was verified with copper and it is suitable also for various other metals. It can be applied for the replication of etched ion tracks and for the fabrication of microstructures containing large numbers of individual metal whiskers.

  15. Process for carbonaceous material conversion and recovery of alkali metal catalyst constituents held by ion exchange sites in conversion residue

    Science.gov (United States)

    Sharp, David W.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered for the particles by contacting or washing them with an aqueous solution containing calcium or magnesium ions in an alkali metal recovery zone at a low temperature, preferably below about 249.degree. F. During the washing or leaching process, the calcium or magnesium ions displace alkali metal ions held by ion exchange sites in the particles thereby liberating the ions and producing an aqueous effluent containing alkali metal constituents. The aqueous effluent from the alkali metal recovery zone is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  16. Effect of Metal Ions on the Formation of Trichloronitromethane during Chlorination of Catechol and Nitrite.

    Science.gov (United States)

    Gan, Guojuan; Mei, Rongwu; Qiu, Lin; Hong, Huachang; Wang, Qingjun; Mazumder, Asit; Wu, Shikai; Pan, Xiangliang; Liang, Yan

    2016-11-01

    Catechol, nitrite, and dissolved metals are ubiquitous in source drinking water. Catechol and nitrite have been identified as precursors for halonitromethanes (HNMs), but the effect of metal ions on HNM formation during chlorination remains unclear. The main objective of this study was to investigate the effect of metal ions (Fe, Ti, Al) on the formation of trichloronitromethane (TCNM) (the most representative HNM species in disinfected water) on chlorinating catechol and nitrite. Trichloronitromethane was extracted by methyl tert-butyl ether and detected by gas chromatography. The results show that metal ions promoted the formation of TCNM and that the enhancement efficiency followed the order of Fe > Ti > Al. Trichloronitromethane formation increased greatly within 2 h, and a basic condition (pH 8-9) favored TCNM formation more than acidic or neutral conditions. The conjoint effect of the metal-ion mixtures was shown to be similar to that of the single metal ion having the highest promoting effect on TCNM formation. Our results strongly suggest that metal ions play a significant role in enhancing TCNM formation.

  17. The Incorporation of Lithium Alloying Metals into Carbon Matrices for Lithium Ion Battery Anodes

    Science.gov (United States)

    Hays, Kevin A.

    arsenic particles that were synthesized on melt away carbon nanotubes by akalide reduction. The performance of these anodes proved sensitive to electrolyte composition, which was significantly improved by using fluorinated ethylene carbonate. Additionally, further gains in capacity retention can be made by limiting the loading voltage to 0.75 V vs lithium metal. The arsenic and melt away carbon nanotube composite was found to have excellent cycle life and capacity at high mass loading (80% arsenic) when the nanoparticles were directly synthesized on the melt away carbon nanotubes. Gallium arsenide is well known for its semiconducting properties, but its performance as in Li-ion battery anodes is first reported here. Gallium is a metal with a low melting point that has been touted as a possible self-healing material for lithium ion anodes. Alone, gallium proves to be unstable as a lithium ion battery anode, but when synthesized as gallium arsenide nanoparticles and mixed with melt away carbon nanotubes it can charge and discharge in a battery 100 times with approximately twice the capacity of graphite anodes. This first study of gallium arsenide shows dramatic cycle life improvements by using nanoscale rather that micron size gallium arsenide.

  18. Oxidation processes on conducting carbon additives for lithium-ion batteries

    KAUST Repository

    La Mantia, Fabio

    2012-11-21

    The oxidation processes at the interface between different types of typical carbon additives for lithium-ion batteries and carbonates electrolyte above 5 V versus Li/Li+ were investigated. Depending on the nature and surface area of the carbon additive, the irreversible capacity during galvanostatic cycling between 2.75 and 5.25 V versus Li/Li+ could be as high as 700 mAh g-1 (of carbon). In the potential region below 5 V versus Li/Li+, high surface carbon additives also showed irreversible plateaus at about 4.1-4.2 and 4.6 V versus Li/Li+. These plateaus disappeared after thermal treatments at or above 150 °C in inert gas. The influence of the irreversible capacity of carbon additives on the overall performances of positive electrodes was discussed. © 2012 Springer Science+Business Media Dordrecht.

  19. Effects of magnetic ion-exchange resin addition during coagulation on floc properties and membrane filtration.

    Science.gov (United States)

    Choi, Yang Hun; Kweon, Ji Hyang; Jeong, Young Mi; Kwon, Soonbuhm; Kim, Hyung-Soo

    2010-03-01

    The application of magnetic ion-exchange resin (MIEX) during chemical coagulation was investigated for the removal of organic matters responsible for fouling in membrane processes. Two different coagulants were used-polyaluminium chloride (PAC1) and polyaluminum chloride silicate (PACS). The MIEX addition during coagulation with both PAC1 and PACS considerably enhanced removal of dissolved organic carbon. Coagulation with MIEX treatment substantially removed all portions of natural organic matter (NOM), while the MIEX treatment alone effectively removed the hydrophobic and transphilic portions of NOM. The enhanced NOM removal by PAC1 coagulation with the addition of MIEX had positive effects on membrane flux at moderate transmembrane pressure conditions. However, the almost identical flux patterns were reported in the experiments of coagulation with PACS and PACS with MIEX addition. The results of the specific cake resistances indicated that the MIEX addition substantially decreased the resistances. The larger size distributions of PAC1 with MIEX corresponded well with the flux improvement.

  20. Metal ion-dependent, reversible, protein filament formation by designed beta-roll polypeptides

    Directory of Open Access Journals (Sweden)

    Campbell Robert L

    2007-10-01

    Full Text Available Abstract Background A right-handed, calcium-dependent β-roll structure found in secreted proteases and repeat-in-toxin proteins was used as a template for the design of minimal, soluble, monomeric polypeptides that would fold in the presence of Ca2+. Two polypeptides were synthesised to contain two and four metal-binding sites, respectively, and exploit stacked tryptophan pairs to stabilise the fold and report on the conformational state of the polypeptide. Results Initial analysis of the two polypeptides in the presence of calcium suggested the polypeptides were disordered. The addition of lanthanum to these peptides caused aggregation. Upon further study by right angle light scattering and electron microscopy, the aggregates were identified as ordered protein filaments that required lanthanum to polymerize. These filaments could be disassembled by the addition of a chelating agent. A simple head-to-tail model is proposed for filament formation that explains the metal ion-dependency. The model is supported by the capping of one of the polypeptides with biotin, which disrupts filament formation and provides the ability to control the average length of the filaments. Conclusion Metal ion-dependent, reversible protein filament formation is demonstrated for two designed polypeptides. The polypeptides form filaments that are approximately 3 nm in diameter and several hundred nm in length. They are not amyloid-like in nature as demonstrated by their behaviour in the presence of congo red and thioflavin T. A capping strategy allows for the control of filament length and for potential applications including the "decoration" of a protein filament with various functional moieties.

  1. Influence of redox mediators and metal ions on synthetic acid dye decolourization by crude laccase from Trametes hirsuta.

    Science.gov (United States)

    Rodríguez Couto, S; Sanromán, Ma; Gübitz, G M

    2005-01-01

    In this paper, the effect of redox mediators on synthetic acid dye decolourization (Sella Solid Red and Luganil Green) by laccase from Trametes hirsuta cultures has been investigated. All the redox mediators tested, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1-hydroxybenzotriazole (HBT) and Remazol Brilliant Blue R (RBBR), led to higher activities than those obtained without mediators addition showing the suitability of the laccase/mediator system (LMS) in the decolourization of acid dyes. HBT was by far the most effective mediator, showing a decolourization percentage of 88% in 10 min for Sella Solid Red and of 49% in 20 min for Luganil Green. On the other hand, the stability of laccase against several metal ions, normally found in textile wastewater, was assessed. Laccase was stable at a concentration of 1mM for 7d against all the metal ions tested except for Zn+2, CrO4(-2), Cd+2, Cr2O7(-2), Fe+2, Cu+2 and especially Hg+2. When the concentration was increased to 10mM laccase stability decreased against all the metals assayed, in particular against Fe+2. In addition, the effect of metal ions on the decolourization process was also studied. It was found that Hg+2 inhibited the dye decolourization process, being the presence of HBT absolutely required for dye decolourization.

  2. Hierarchical assembly of collagen peptide triple helices into curved disks and metal ion-promoted hollow spheres.

    Science.gov (United States)

    Przybyla, David E; Rubert Pérez, Charles M; Gleaton, Jeremy; Nandwana, Vikas; Chmielewski, Jean

    2013-03-06

    A 27 amino acid collagen-based peptide (Hbyp3) was designed to radially display nine hydrophobic bipyridine moieties from a triple helical scaffold. Self-assembly of such functionalized triple helices led to the formation of micrometer-scaled disks with a curved morphology, presumably mediated by aromatic interactions, with a height that is in the range of the length of the triple helical peptide. Higher order assembly of these curved disks into micrometer-sized hollow spheres was accomplished through metal-ligand interactions between bipyridine groups of the disks and metal ions such as Fe(II), Co(II), Zn(II) and Cu(II). The thickness of the shell of these hollow spheres corresponds well with the thickness of the collagen peptide-based triple helix and the corresponding self-assembled disks. Addition of a metal ion chelator was found to reverse the assembly of the hollow spheres back to the curved disk structures. These data support the formation of the hollow spheres from the self-assembled disks of Hbyp3 upon addition of metal ions.

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

    African Journals Online (AJOL)

    Administrator

    2011-09-26

    Sep 26, 2011 ... The effects of several metal ions on the cell growth, production of polysaccharides by ... in vegetarian diets and regarded as medicinal food that ... Many factors including nutrition ... in submerged fermentation is relatively poor.

  4. Non-centrosymmetric behavior of a clay film ion-exchanged with chiral metal complexes.

    Science.gov (United States)

    Suzuki, Yasutaka; Matsunaga, Ryoya; Sato, Hisako; Kogure, Toshihiro; Yamagishi, Akihiko; Kawamata, Jun

    2009-12-07

    SHG measurements on a highly transparent clay film ion-exchanged with chiral metal complexes revealed that the mono-molecular layer of the chiral complexes in an interlayer space acquired a non-centrosymmetric character.

  5. Photodetachment of negative ion in a gradient electric field near a metal surface

    Institute of Scientific and Technical Information of China (English)

    Liu Tian-Qi; Wang De-Hun; Han Cai; Liu Jiang; Liang Dong-Qi; Xie Si-Cheng

    2012-01-01

    Based on closed-orbit theory,the photodetachment of Hˉ in a gradient electric field near a metal surface is studied.It is demonstrated that the gradient electric field has a significant influence on the photodetachment of negative ions near a metal surface.With the increase of the gradient of the electric field,the oscillation in the photodetachment cross section becomes strengthened.Besides,in contrast to the photodetachment of Hˉ near a metal surface in a uniform electric field,the oscillating amplitude and the oscillating region in the cross section of a gradient electric field also become enlarged.Therefore,we can use the gradient electric field to control the photodetachment of negative ions near a metal surface.We hope that our results will be useful for understanding the photodetachment of negative ions in the vicinity of surfaces,cavities,and ion traps.

  6. Growth of cyanophage N-1 under the influence of heavy metal ions.

    Science.gov (United States)

    Sarma, T A; Kaur, Sukhrish P

    2005-01-01

    The growth of cyanophage N-1 in the cyanobacterium Nostoc muscorum under the influence of heavy metal ions, namely Co2+, Cr6+, Cu2+, Mn2+ and Ni2+ has been studied. One-step growth experiments revealed that heavy metal ions extended the latent period by 1-2 hrs with a concomitant decrease in the phage burst size. The latter was reduced in the order Cu2/Mn2+, Ni2+, Co2+ and Cr6+. The treatment of the phage-infected bacteria with heavy metal ions did not induce mutations affecting either the phage plaque morphology or burst size. The final phage titer after such a treatments was lowest with Co2+, Cu2+ and Cr6+. The inhibition of the phage growth under the influence of heavy metal ions is discussed in context with the interaction of cyanophage N-1 with the photosynthetic reactions in the host bacteria.

  7. Colorimetric chemosensor for multi-signaling detection of metal ions using pyrrole based Schiff bases.

    Science.gov (United States)

    Udhayakumari, Duraisamy; Velmathi, Sivan

    2014-03-25

    Pyrrole based Schiff bases act as a highly sensitive probe for metal ions in aqueous medium. Both receptors R1 and R2 are sensitive towards Fe(3+), Cu(2+), Hg(2+) and Cr(3+) among the other metal ions. The sensing ability of the receptors are investigated via colorimetric, optical and emission spectroscopic studies. The binding stoichiometries of R1 and R2 with metal ions have been determined as 2:1 by using Job's plot. The colorimetric receptors exhibited high sensitivity with a low detection limit of μM levels. In the presence of metal ions both receptors shows fluorescence quenching. This might be due to the photo induced electron transfer mechanism. The quenching constant was further determined using Stern-Volmer plot.

  8. Topological design and additive manufacturing of porous metals for bone scaffolds and orthopaedic implants: A review.

    Science.gov (United States)

    Wang, Xiaojian; Xu, Shanqing; Zhou, Shiwei; Xu, Wei; Leary, Martin; Choong, Peter; Qian, M; Brandt, Milan; Xie, Yi Min

    2016-03-01

    One of the critical issues in orthopaedic regenerative medicine is the design of bone scaffolds and implants that replicate the biomechanical properties of the host bones. Porous metals have found themselves to be suitable candidates for repairing or replacing the damaged bones since their stiffness and porosity can be adjusted on demands. Another advantage of porous metals lies in their open space for the in-growth of bone tissue, hence accelerating the osseointegration process. The fabrication of porous metals has been extensively explored over decades, however only limited controls over the internal architecture can be achieved by the conventional processes. Recent advances in additive manufacturing have provided unprecedented opportunities for producing complex structures to meet the increasing demands for implants with customized mechanical performance. At the same time, topology optimization techniques have been developed to enable the internal architecture of porous metals to be designed to achieve specified mechanical properties at will. Thus implants designed via the topology optimization approach and produced by additive manufacturing are of great interest. This paper reviews the state-of-the-art of topological design and manufacturing processes of various types of porous metals, in particular for titanium alloys, biodegradable metals and shape memory alloys. This review also identifies the limitations of current techniques and addresses the directions for future investigations.

  9. Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin.

    Science.gov (United States)

    Lee, I Hsien; Kuan, Yu-Chung; Chern, Jia-Ming

    2006-12-01

    Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 degrees C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results.

  10. Occurrence of metal ions in rice produced in Uruguay

    Directory of Open Access Journals (Sweden)

    Mario Rivero

    2011-04-01

    Full Text Available The United Nations General Assembly declared the year 2004 the International Year of Rice under the concept "Rice is Life". The largest nutritional problems occurring globally are protein-energy malnutrition, Ca, Fe, I, Zn and vitamin A deficiencies. Being rice the staple food more consumed worldwide, outstanding care is taken on its composition levels.Uruguay has emerged as medium-size rice producer and Latin America's major rice exporter, and is now amongst the world's top ten. Thus, the knowledge of toxic as well as micronutrient elements is very important. Here is reported the determination in forty nine samples of rice (Oryza sativa L. of As, Cd, Cr, and Pb by ET AAS in samples digested by dry ashing, and Ca, Co, Cu, Fe, K, Mg, Mo, Mn, Na, Ni and Zn by FAAS and Hg by CV AAS using microwave-assisted decomposition.The amount of all the metal ions studied in this work fall within the range typical of rice around the world. All the rice samples tested showed lower levels of As, Cd, Hg and Pb than the maximum limit permitted by governmental and international organizations.Potassium was the most abundant mineral followed by Mg and Ca and amongst microelements the presence of Cu, Fe, Mo, Mn, Na and Zn was outstanding.The milling process highly affects the contents of K, Mg, Mn, Na and Zn while little influence has on Ca, Co, Cu and Fe concentrations.Unexpected loss of Ca, Fe and Mn during parboiling process was detected. 

  11. Metal-carbon clusters: The origin of the delayed atomic ion

    Science.gov (United States)

    Davis, K. M.; Peppernick, S. J.; Castleman, A. W.

    2006-04-01

    Studies of the emission of electrons from excited metal-carbon cluster systems that include the Met-Car (M8C12, where M is Ti, Zr, and V) also have revealed the evolution of a delayed atomic ion. The source of the delayed atomic ion, which involves the emission of ionized atoms on the microsecond time scale, is the focus of this investigation. By studying the delayed ionization of mixed zirconium and titanium carbon complexes produced in a laser vaporization source coupled to a time-of-flight mass spectrometer, for the first time both the zirconium and titanium delayed atomic ions were observed to be emitted in the same experiment. These studies allowed a determination that the source of the delayed atomic ion is an excited metal dicarbide. A plausible mechanism involving the excitation of a high Rydberg state of the metal dicarbide prior to an excited ion pair separation is proposed.

  12. First-principles calculations on implanted TiO2 by 3d transition metal ions

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    3d transition metal (V, Cr and Fe) ions are implanted into TiO2 by the method of metal ion implantation. The electronic band structures of TiO2 films doped 3d transition metal ions have been analyzed by ab initio band calculations based on a self-consistent full-potential linearized augmented plane-wave method within the first-principle formalism. Influence of implantation on TiO2 films is examined by the method of UV-visible spectrometry. The results of experiment and calculation show that the optical band gap of TiO2 films is narrowed by ion implantation. The calculation shows that the 3d state of V, Cr and Fe ions plays a significant role in red shift of UV-Vis absorbance spectrum.

  13. Effect of Metal Additives on Performance of Low-Carbon Magnesia-Carbon Materials

    Institute of Scientific and Technical Information of China (English)

    PENG Xiaoyan; LI Lin; HE Zhiyong; LIU Kaiqi; WANG Bingjun

    2007-01-01

    In this paper, both oxidation and corrosion resistance of low-carbon magnesia-carbon materials containing 4.0wt% graphite with metallic Al and Mg-Al alloy powders as antioxidants were investigated. Meanwhile,the microstructures of samples corroded by slag were observed with optical microscope as well. The test results revealed the properties of oxidation and corrosion resistance of low-carbon magnesia-carbon materials could be improved obviously by adding metal Al powder and Mg-Al alloy powder. The rule of improving oxidation resistance was illegibility when metal Al powder and Mg-Al alloy powder were added together. It was harmful to corrosion resistance by mixed adding metal Al powder and Mg-Al alloy powder into the materials, at the same time, the corrosion resistance would decreased with the increasing of Mg-Al alloy content. The corrosion resistance of samples with 0.5wt% or 3.0wt% Mg-Al alloy was better. The oxidation resistance and corrosion resistance of materials with metal Al or Mg-Al alloy respectively were better than that with mixed metal Al and Mg-Al alloy. As a result, Mg-Al alloy was more suitable for low-carbon composite materials than metal Al as additives.

  14. 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 ...... ions, rubidium ions and caesium ions....

  15. Effect of metallic additives on in situ combustion of Huntington Beach crude experiments

    Energy Technology Data Exchange (ETDEWEB)

    Baena, C.J.; Castanier, L.M.; Brigham, W.E.

    1990-08-01

    The economics and applicability of an in-situ combustion process for the recovery of crude oil are dictated to a large extent by the nature and the amount of fuel formed during the process. The aim of this work is to use combustion tube studies to determine on a quantitative basis, how the nature and the amount of fuel formed could be changed by the presence of metallic additives. These experiments follow from the qualitative observations on the effect of metallic additives on the in-situ combustion of Huntington Beach crude oil made by De los Rios (1987) at SUPRI. He performed kinetic studies on the oxidation of Huntington Beach crude in porous media and showed that the nature of the fuel formed changed when metallic additives were present. Combustion tube runs were performed using the metallic additives: ferrous chloride (FeCl{sub 2{center dot}}4H{sub 2}O), zinc chloride (ZnCl{sub 2}) and stannic chloride (SnCl{sub 4{center dot}}5H{sub 2}O). Unconsolidated cores were prepared by mixing predetermined amounts of an aqueous solution of the metal salt, Huntington Beach crude oil, Ottawa sand and clay in order to achieve the desired fluid saturations. The mixture was then tamped into the combustion tube. Dry air combustion tube runs were performed keeping the conditions of saturation, air flux and injection pressure approximately the same during each run. The nature of the fuel formed and its impact on the combustion parameters were determined and compared with a control run -- an experiment performed with no metallic additive. 30 refs., 33 figs., 6 tabs.

  16. Syntheses and metal ions recognition of dendritic calix[n]arenes(n=6,8)amide derivative

    Institute of Scientific and Technical Information of China (English)

    WANG Yunyan; CAI Yahua; YAN Chaoguo

    2007-01-01

    Dendritic p-t'butylcalix[n]arene amide derivatives with terminal amino groups of the first and second generations were synthesized by using divergent methods from ammonolysis of ethyl calixarylacetate with 1,6-diaminohexane and Michael addition of methyl acrylate.Their structures were confirmed by IR,1H NMR.The recognition properties of these amide derivatives for several kinds of metal ions were studied with UV-Vis spectroscopy.The results showed a great affinity for soft Ag+ and UO22+ ions and formed 1:2 or 1:3 stoichiometric complexes.

  17. Heavy Metal Accumulation and Ecological Responses of Turfgrass to Rubbish Compost with EDTA Addition

    Institute of Scientific and Technical Information of China (English)

    Li-An DUO; Yu-Bao GAO; Shu-Lan ZHAO

    2005-01-01

    Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals,which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L.and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of1914.17 and 521.25 μg/g, respectively. When the EDTA level was < 20 mmol/kg, the accumulation of most heavy metals in F. arundinacea increased with increasing EDTA supply, but showed a tendency to decrease at EDTA concentrations >20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F.arundinacea reached 268.01, 110.94, 161.52 and 1 354.97 μg/g, respectively, following the addition of 20mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plantand metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49-fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration (596.02 μg/g) seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations <10mmol/kg increased seed germination and aboveground net primary production (ANP) of L. perenne and slightly inhibited those of F.arundinacea, but EDTA at

  18. Differential pulse voltammetry and additive differential pulse voltammetry with solvent polymeric membrane ion sensors.

    Science.gov (United States)

    Ortuño, J A; Serna, C; Molina, A; Gil, A

    2006-12-01

    The ion transfer across the water-solvent polymeric membrane interface is investigated by using a new device based on a modification of a commercial ion-selective electrode body that permits the accommodation of a platinum counter electrode inside the inner filling solution compartment and, therefore, use of a four-electrode potentiostat with ohmic drop compensation. This device is used here to apply two different double potential pulse techniques--differential pulse voltammetry and additive differential pulse voltammetry--which are more advantageous than other voltammetric techniques, such as normal pulse voltammetry or cyclic voltammetry, for the determination of the characteristic electrochemical parameters of the system. This is due to the concurrence of two factors in these double potential pulse techniques, the peak-shaped response together with a considerable reduction of undesirable current contributions.

  19. Removing adsorbed heavy metal ions from sand surfaces via applying interfacial properties of rhamnolipid.

    Science.gov (United States)

    Haryanto, Bode; Chang, Chien-Hsiang

    2015-01-01

    In this study, the interfacial properties of biosurfactant rhamnolipid were investigated and were applied to remove adsorbed heavy metal ions from sand surfaces with flushing operations. The surface tension-lowering activity, micelle charge characteristic, and foaming ability of rhamnolipid were identified first. For rhamnolipid in water, the negatively charged characteristic of micelles or aggregates was confirmed and the foaming ability at concentrations higher than 40 mg/L was evaluated. By using the rhamnolipid solutions in a batch washing approach, the potential of applying the interfacial properties of rhamnolipid to remove adsorbed copper ions from sand surfaces was then demonstrated. In rhamnolipid solution flushing operations for sand-packed medium, higher efficiency was found for the removal of adsorbed copper ions with residual type than with inner-sphere interaction type, implying the important role of interaction type between the copper ion and the sand surface in the removal efficiency. In addition, the channeling effect of rhamnolipid solution flow in the sand-packed medium was clearly observed in the solution flushing operations and was responsible for the low removal efficiency with low contact areas between solution and sand. By using rhamnolipid solution with foam to flush the sand-packed medium, one could find that the channeling effect of the solution flow was reduced and became less pronounced with the increase in the rhamnolipid concentration, or with the enhanced foaming ability. With the reduced channeling effect in the flushing operations, the removal efficiency for adsorbed copper ions was significantly improved. The results suggested that the foam-enhanced rhamnolipid solution flushing operation was efficient in terms of surfactant usage and operation time.

  20. THE TRANSFER OF ALKALINE EARTH-METAL ION AT W/NB INTERFACE FACILITATED BY JOSAMYCIN

    Institute of Scientific and Technical Information of China (English)

    范瑞溪; 狄俊伟

    1991-01-01

    This paper describes the invesligation of the transfer behaviour of the alkaline earth-metal cations across the water/nitrobenzene interface facilitated by josamycin in the nitrobenzene phase using semi-differential cyclic voltammetry .The peak height is directly proportional to the concentration of josaycin (nb) and to the potential scan rate.The complexes formed from alkaline earth-metal ions and josamycin at the w/nb interface are ML22+ ion.

  1. Study of application of hydrophobic fibrous sorbents for water purification from metal ions

    OpenAIRE

    Е. V. Petrova; Astashkina, А. P.; Filonenko, D. А.; Otmakhov, V. I.; Izaak, Т. I.; Volokitin, G. G.

    2007-01-01

    Sorption properties of hydrophobic fibrous sorbents on the basis of polypropylene and polyethylene terephthalate produced from thermoplastic polymer wastes to metal ion series in aqueous media has been studied. Based on the experimental data of extraction degree dependencies on fibre laying density, dispersity, presence of air in sorbent, volume of pass solution the mechanism of metal ion sorption from aqueous media with hydrophobic fibrous materials is suggested.

  2. Coordination of cassava starch to metal ions and thermolysis of resulting complexes

    Directory of Open Access Journals (Sweden)

    Piotr Tomasik

    2003-12-01

    Full Text Available 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 lower temperature than did starch. On the other hand, the decomposition proceeded at a lower rate than the decomposition of non-coordinated starch.

  3. 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).

  4. Metal ions as cofactors for aggregation of therapeutic peptide salmon calcitonin.

    Science.gov (United States)

    Rastogi, Neeraj; Mitra, Kalyan; Kumar, Dinesh; Roy, Raja

    2012-05-21

    The effects of multivalent metal ions (Cu(2+)/Zn(2+)/Al(3+)) on the aggregation of salmon calcitonin (sCT)--a therapeutic peptide used worldwide in the treatment of osteoporosis and Paget's disease--have been studied in vitro using NMR (both solution state and solid state), TEM, ThT-fluorescence, and FT-IR spectroscopy. Overall, the various results indicated that the metal-ions-induced conformational transitions in the peptide--mostly toward the β-sheet--facilitate the aggregation of sCT in solution. First, the solution NMR has been used to check the interaction between the peptide and the metal ions. Following this, the formation and characterization of calcitonin aggregates has been performed using TEM, solid state NMR, and FT-IR spectroscopy. The TEM and ThT-fluorescence results revealed that the sCT peptide incubated with Cu(2+) and Zn(2+) metal ions (in aqueous environment) forms globular aggregates, while that with Al(3+) ions forms fibrils. The solid state NMR and FT-IR studies revealed the presence of a substantial amount of β-sheet content in sCT aggregates (formed in the presence of these metal ions) compared to the monomeric sCT, indicating that the metal binding is concomitant with conformational changes. The present study becomes crucial while prescribing this drug peptide under physio-pathological conditions associated with an abnormal accumulation of metal ions (Cu(2+)/Zn(2+)/Al(3+)) in the body (i.e., abnormal metal ion homeostasis).

  5. Tuning the chemical selectivity of SWNT-FETs for detection of heavy-metal ions.

    Science.gov (United States)

    Forzani, Erica S; Li, Xiulan; Zhang, Peiming; Tao, Nongjian; Zhang, Ruth; Amlani, Islamshah; Tsui, Raymond; Nagahara, Larry A

    2006-11-01

    A method to functionalize single-walled carbon nanotubes (SWNTs) in a field-effect transistor (FET) device for the selective detection of heavy-metal ions is presented. In this method, peptide-modified polymers were electrochemically deposited onto SWNTs and the selective detection of metal ions was demonstrated by choosing appropriate peptide sequences. The signal transduction mechanism of the peptide-modified SWNT-FETs has also been studied.

  6. The role of metal ions in X-ray induced photochemistry

    CERN Document Server

    Stumpf, Vasili; Cederbaum, Lorenz S

    2015-01-01

    Metal ions play numerous important roles in biological systems being central to the function of biomolecules. In this letter we show that the absorption of X-rays by these ions leads to a complicated chain of ultrafast relaxation steps resulting in the complete degradation of their nearest environment. We conducted high quality ab initio studies on microsolvated Mg clusters demonstrating that ionisation of an 1s-electron of Mg leads to a complicated electronic cascade comprising both intra- and intermolecular steps and lasting only a few hundreds femtoseconds. The metal cation reverts to its original charge state at the end of the cascade, while the nearest solvation shell becomes multiply ionised and large concentrations of radical and slow electron species build up in the metal vicinity. We conclude that such cascades involving metal ions are essential for understanding the radiation chemistry of solutions and radiation damage to metal containing biomolecules.

  7. 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 within...... isolated I domains in regulating ligand binding has been reported, the relationship between metal ion binding affinity and ligand binding affinity has not been elucidated. Metal and ligand binding by several I domain mutants that are stabilized in different conformations are investigated using isothermal...... titration calorimetry and surface plasmon resonance studies. This work suggests an inverse relationship between metal ion affinity and ligand binding affinity (i.e. constructs with a high affinity for ligand exhibit a low affinity for metal). This trend is discussed in the context of structural studies...

  8. Stepwise assembly of mixed-metal coordination cages containing both kinetically inert and kinetically labile metal ions: introduction of metal-centred redox and photophysical activity at specific sites.

    Science.gov (United States)

    Wragg, Ashley B; Metherell, Alexander J; Cullen, William; Ward, Michael D

    2015-11-01

    Stepwise preparation of the heterometallic octanuclear coordination cages [(M(a))4(M(b))4L12](16+) is reported, in which M(a) = Ru or Os and M(b) = Cd or Co (all in their +2 oxidation state). This requires initial preparation of the kinetically inert mononuclear complexes [(M(a))L3](2+) in which L is a ditopic ligand with two bidentate chelating pyrazolyl-pyridine units: in the complexes [(M(a))L3](2+) one terminus of each ligand is bound to the metal ion, such that the complex has three pendant bidentate sites at which cage assembly can propagate by coordination to additional labile ions M(b) in a separate step. Thus, combination of four [(M(a))L3](2+) units and four [M(b)](2+) ions results in assembly of the complete cages [(M(a))4(M(b))4L12](16+) in which a metal ion lies at each of the eight vertices, and a bridging ligand spans each of the twelve edges, of a cube. The different types of metal ion necessarily alternate around the periphery with each bridging ligand bound to one metal ion of each type. All four cages have been structurally characterised: in the Ru(ii)/Cd(ii) cage (reported in a recent communication) the Ru(ii) and Cd(ii) ions are crystallographically distinct; in the other three cages [Ru(ii)/Co(ii), Os(ii)/Cd(ii) and Os(ii)/Co(ii), reported here] the ions are disordered around the periphery such that every metal site refines as a 50 : 50 mixture of the two metal atom types. The incorporation of Os(ii) units into the cages results in both redox activity [a reversible Os(ii)/Os(iii) couple for all four metal ions simultaneously, at a modest potential] and luminescence [the Os(ii) units have luminescent (3)MLCT excited states which will be good photo-electron donors] being incorporated into the cage superstructure.

  9. Preparation, investigation of metal ion removal and flocculation performances of grafted hydroxyethyl starch.

    Science.gov (United States)

    Kolya, Haradhan; Tripathy, Tridib

    2013-11-01

    Ceric ion induced graft copolymerization of N,N-dimethyl acrylamide (DMA) and acryl amide (AM) were carried out onto the hydroxyethyl starch (HES). These grafted copolymers were used for the removal of metal ions from their aqueous solutions. Flocculation performances of the synthesized graft copolymers were evaluated in 1.0 wt% silica suspensions. A comparative study of the flocculation performances of the synthetic graft copolymers was also made. The different factors affecting metal ion absorption, namely pH, treatment time, temperature and polymer dose were studied. A comparative study of the metal ion removal capacity of the two synthetic graft copolymers was also made in five metal ions namely Ni(II), Zn(II), Cu(II), Pb(II) and Hg(II). The metal ion removal capacity follows the order Hg(II)>Cu(II)>Zn(II)>Ni(II)>Pb(II) in both the two synthetic polymers. Between the two graft copolymers, graft copolymer based on AM shows better performance than that based on DMA in all the metal solutions. But the flocculation performance of DMA based graft copolymer showed better performances than that AM based graft copolymer. The former also performed best when compared to the commercial flocculants in the same suspension.

  10. Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

    Science.gov (United States)

    Erdogan, Ayse Tuygun; Nalbantgil, Didem; Ulkur, Feyza; Sahin, Fikrettin

    2015-07-01

    To compare metal ion release from samples welded with silver soldering and laser welding when immersed into mouthwashes with different ingredients. A total of 72 samples were prepared: 36 laser welded and 36 silver soldered. Four samples were chosen from each subgroup to study the morphologic changes on their surfaces via scanning electron microscopy (SEM). Each group was further divided into four groups where the samples were submerged into mouthwash containing sodium fluoride (NaF), mouthwash containing sodium fluoride + alcohol (NaF + alcohol), mouthwash containing chlorhexidine (CHX), or artificial saliva (AS) for 24 hours and removed thereafter. Subsequently, the metal ion release from the samples was measured with inductively coupled plasma mass spectrometry (ICP-MS). The metal ion release among the solutions and the welding methods were compared. The Kruskal-Wallis and analysis of variance (ANOVA) tests were used for the group comparisons, and post hoc Dunn multiple comparison test was utilized for the two group comparisons. The level of metal ion release from samples of silver soldering was higher than from samples of laser welding. Furthermore, greater amounts of nickel, chrome, and iron were released from silver soldering. With regard to the mouthwash solutions, the lowest amounts of metal ions were released in CHX, and the highest amounts of metal ions were released in NaF + alcohol. SEM images were in accord with these findings. The laser welding should be preferred over silver soldering. CHX can be recommended for patients who have welded appliances for orthodontic reasons.

  11. 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.

  12. A mechanistic model for depth-dependent hardness of ion irradiated metals

    Science.gov (United States)

    Xiao, Xiazi; Chen, Qianying; Yang, Hui; Duan, Huiling; Qu, Jianmin

    2017-03-01

    A mechanistic model was developed for modeling the depth-dependent hardness in ion irradiated metallic materials. The model is capable of capturing the indentation size effect, ion irradiation induced damage gradient effect, and effect of unirradiated region acting as a soft substrate. A procedure was developed and described in detail to parametrize the model based on experimentally obtained hardness vs. indentation depth curves. Very good agreement was observed between our model predictions and experimental data of several different stainless steels subjected to various ion irradiation conditions. In addition, two hardening mechanisms are revealed in the new model. One is the well-known indentation size effect arising from the creation of geometrically necessary dislocations as the indenter pierces into the materials. The other is the irradiation hardening due to the presence of irradiation-induced defects. As a function of indentation depth h, the hardening due to indentation size effect is described by hbar∗ / h , while the hardening due to irradiation first follows a power law form Phn , then changes to Z / h - Q /h3 , where hbar∗ , P, n, Z and Q > 0 are constants. This transition occurs at the indentation depth when the plastic zone reaches the end of the irradiated layer.

  13. Production of multicharged metal ion beams on the first stage of tandem-type ECRIS

    Energy Technology Data Exchange (ETDEWEB)

    Hagino, Shogo, E-mail: hagino@nf.eie.eng.osaka-u.ac.jp; Nagaya, Tomoki; Nishiokada, Takuya; Otsuka, Takuro; Sato, Fuminobu; Kato, Yushi [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita-shi, Osaka 565-0871 (Japan); Muramatsu, Masayuki; Kitagawa, Atsushi [National Institute of Radiological Sciences (NIRS), 4-9-1, Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

    2016-02-15

    Multicharged metal ion beams are required to be applied in a wide range of fields. We aim at synthesizing iron-endohedral fullerene by transporting iron ion beams from the first stage into the fullerene plasma in the second stage of the tandem-type electron cyclotron resonance ion source (ECRIS). We developed new evaporators by using a direct ohmic heating method and a radiation heating method from solid state pure metal materials. We investigate their properties in the test chamber and produce iron ions on the first stage of the tandem-type ECRIS. As a result, we were successful in extracting Fe{sup +} ion beams from the first stage and introducing Fe{sup +} ion beams to the second stage. We will try synthesizing iron-endohedral fullerene on the tandem-type ECRIS by using these evaporators.

  14. 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.

  15. Mitigation of Metal Ion Pollution from Industrial Waste Water Using Waste Wool

    Science.gov (United States)

    Prajapat, Garima; Purohit, Praveen

    A study on the adsorption of copper (II) ions from the aqueous solution on waste wool had been carried out to analyze the adsorption capacity of waste wool, thereby aiming towards mitigation of metal ion pollution in industrial waste water. The effect of varying concentration of copper ions and varying time period, was studied on fixed weight of waste wool. The initial and final concentration of copper ions was measured by conductometric and spectrophotometric methods. Adsorption data were modeled with the langmuir and freundlich adsorption isotherms. The isotherm and first order equation were found to be applicable. Removal of metal ions using industrial waste wool is found to be favourable. Thus the work can be extended to study various physico-chemical parameters for removal of copper (II) ions from industrial effluents using waste wool. A later work can be involved where the waste wool adsorption parameter can be further utilized for composite ceramic products.

  16. Production of multicharged metal ion beams on the first stage of tandem-type ECRIS

    Science.gov (United States)

    Hagino, Shogo; Nagaya, Tomoki; Nishiokada, Takuya; Otsuka, Takuro; Muramatsu, Masayuki; Kitagawa, Atsushi; Sato, Fuminobu; Kato, Yushi

    2016-02-01

    Multicharged metal ion beams are required to be applied in a wide range of fields. We aim at synthesizing iron-endohedral fullerene by transporting iron ion beams from the first stage into the fullerene plasma in the second stage of the tandem-type electron cyclotron resonance ion source (ECRIS). We developed new evaporators by using a direct ohmic heating method and a radiation heating method from solid state pure metal materials. We investigate their properties in the test chamber and produce iron ions on the first stage of the tandem-type ECRIS. As a result, we were successful in extracting Fe+ ion beams from the first stage and introducing Fe+ ion beams to the second stage. We will try synthesizing iron-endohedral fullerene on the tandem-type ECRIS by using these evaporators.

  17. Triethylborate as an electrolyte additive for high voltage layered lithium nickel cobalt manganese oxide cathode of lithium ion battery

    Science.gov (United States)

    Wang, Zaisheng; Xing, Lidan; Li, JianHui; Xu, Mengqing; Li, Weishan

    2016-03-01

    Triethylborate (TEB) is used as an electrolyte additive to improve the electrochemical performances of LiNi1/3Co1/3Mn1/3O2 (LNCM) upon cycling at 4.5 V vs. Li/Li+. Charge/discharge tests demonstrate that the cyclic stability of LNCM at room and elevated temperature can be improved effectively by TEB. With addition of 10 wt. % TEB into STD electrolyte (1.0 M LiPF6/EC:EMC:DEC), LNCM achieves a capacity retention of 99.8% after 150 cycles and 94.7% after 120 cycles at room and elevated temperature, respectively, comparing to that of 68.9% and 68.8% of STD electrolyte. In addition, 10 wt. % TEB also improves the rate capability of LNCM at room temperature. Physical and electrochemical characterizations from XRD, SEM, TEM, XPS, ICP-MS, LSV, CA, and EIS reveal that the preferential oxidative reaction of TEB generates a thin, uniform and low interfacial resistance film on the LNCM surface. This film not only suppresses the subsequent decomposition of STD electrolyte, but also prevents the dissolution of transition metal ions from LNCM, resulting in improved cyclic stability and rate capability of LNCM.

  18. Metal ions affecting the pulmonary and cardiovascular systems.

    Science.gov (United States)

    Corradi, Massimo; Mutti, Antonio

    2011-01-01

    Some metals, such as copper and manganese, are essential to life and play irreplaceable roles in, e.g., the functioning of important enzyme systems. Other metals are xenobiotics, i.e., they have no useful role in human physiology and, even worse, as in the case of lead, may be toxic even at trace levels of exposure. Even those metals that are essential, however, have the potential to turn harmful at very high levels of exposure, a reflection of a very basic tenet of toxicology--"the dose makes the poison." Toxic metal exposure may lead to serious risks to human health. As a result of the extensive use of toxic metals and their compounds in industry and consumer products, these agents have been widely disseminated in the environment. Because metals are not biodegradable, they can persist in the environment and produce a variety of adverse effects. Exposure to metals can lead to damage in a variety of organ systems and, in some cases, metals also have the potential to be carcinogenic. Even though the importance of metals as environmental health hazards is now widely appreciated, the specific mechanisms by which metals produce their adverse effects have yet to be fully elucidated. The unifying factor in determining toxicity and carcinogenicity for most metals is the generation of reactive oxygen and nitrogen species. Metal-mediated formation of free radicals causes various modifications to nucleic acids, enhanced lipid peroxidation, and altered calcium and sulfhydryl homeostasis. Whilst copper, chromium, and cobalt undergo redox-cycling reactions, for metals such as cadmium and nickel the primary route for their toxicity is depletion of glutathione and bonding to sulfhydryl groups of proteins. This chapter attempts to show that the toxic effects of different metallic compounds may be manifested in the pulmonary and cardiovascular systems. The knowledge of health effects due to metal exposure is necessary for practising physicians, and should be assessed by inquiring

  19. Study on the Flocculability of Metal Ions by Bacillus Mucilaginosus GY03 Strain

    Institute of Scientific and Technical Information of China (English)

    连宾; 陈烨; 袁生; 朱立军; 刘丛强

    2004-01-01

    This study deals with the flocculability of two types of metal ions by Bacillus mucilaginosus GY03 Strain, with an emphasis on the influence of pH conditions, volume and time of flocculants produced by GY03 Strain on the adsorption of metal irons such as Pb+2 and Mn+2 and the capabilities of flocculants to adsorb metal ions of different concentrations. The results showed that microbial flocculants produced by Bacillus mucilaginosus GY03 Strain are highly capable of flocculating metal ions, but show different effectiveness with respect to the adsorption of Pb+2 and Mn+2. In accordance with the experimental data and actual waste-water treatment conditions, the relevant regression equation of flocculation has been deduced, which has found some application in practice. The experimental results of this study demonstrated that microbial flocculants produced by Bacillus mucilaginosus can be used to treat metallic ion-containing waste water. In practical application the volume of microbial flocculants required and flocculation conditions should be taken into comprehensive consideration in accordance with the properties of metal ions, the composition of anions and the solubility of other metals, in combination with the cost and effectiveness of flocculants to be used. Flocculant used in this experiment has the advantages of being applied over a wide range of pH values, small flocculant volume, and rapid speed of flocculation. So this kind of flocculant is within excellent prospect of application.

  20. Interactions of atrazine with transition metal ions in aqueous media: experimental and computational approach.

    Science.gov (United States)

    Kumar, Vijay; Kumar, Virender; Upadhyay, Niraj; Sharma, Sitansh

    2015-10-01

    Transition metal ions have their own significances and utility. Externally applied pesticides may alter the bioavailability of these metal ions to plants through the coordinating ability of these pesticides with metal ions. In current study a series of metal complexes containing atrazine (Atr) group(s) attached to metal(II) (M) frame, with the formula; [M(Atr)n.xH2O.yCl] (where M = Mn, Fe, Co, Ni, Cu or Zn; n = 1 or 2; x = 1-4; y = 1-2), have been synthesized for the first time to check the interactions of atrazine with transition metal ions. More importantly, all the complexes were synthesized at neutral pH in aqueous medium. The major differences among the FTIR spectra were observed between 3,700-2,800 and 1,800-1,350 cm(-1). On the basis of FTIR, CHN and computational study, it was observed that Mn, Ni and Cu formed complexes in 1:2 and Fe, Co and Zn in 1:1. The obtained results were supported by 3D molecular modeling using GAMESS computations as a package of ChemBio3D Ultra14 program. The FTIR spectral analysis and 3D molecular modeling suggests that the Atr can show coordination through the nitrogen (in between two side chains) of ring as well as nitrogen (non steric amine) of side chain with different metal ions.

  1. GaBi alloy liquid metal ion source for microelectronics research.

    Science.gov (United States)

    Bischoff, L; Pilz, W; Ganetsos, Th; Forbes, R G; Akhmadaliev, Ch

    2007-09-01

    A GaBi alloy liquid metal ion source has been studied. From an analysis of the source mass spectra as a function of emission current, a mechanism is suggested for the production of single- and double-charged ions. There is good agreement with the results of Swanson's investigations of a pure Bi source.

  2. On the single-ion Magnetic Anisotropy of the Rare-Earth Metals

    DEFF Research Database (Denmark)

    Kolmakova, N.P.; Tishin, A.M.; Bohr, Jakob

    1996-01-01

    The temperature dependences of the single-ion magnetic anisotropy constants for Tb and Dy metals are calculated in terms of the multipole moments of the rare-earth ions utilizing the available crystal-field parameters. The results are compared with the existing experimental data....

  3. Metal ion induced FRET OFF-ON in tren/dansyl-appended rhodamine.

    Science.gov (United States)

    Lee, Min Hee; Kim, Hyun Jung; Yoon, Sangwoon; Park, Noejung; Kim, Jong Seung

    2008-01-17

    A series of new fluorescent probes bearing tren-spaced rhodamine B and dansyl groups have been synthesized. Compound 1 exhibits selective changes in the absorption and the emission spectra toward Cu2+ ion over miscellaneous metal cations. Among 1-3, 1 shows the best FRET efficiency through dansyl emission to rhodamine absorption for the Cu2+ ion.

  4. Metal Cation Binding to Gas-Phase Pentaalanine: Divalent Ions Restructure the Complex

    NARCIS (Netherlands)

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

    2013-01-01

    Ion-neutral complexes of pentaalalanine with several singly- and doubly charged metal ions are examined using conformation analysis by infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) computations. The infrared spectroscopy in the 1500-1800 cm(-1) region

  5. Metal Cation Binding to Gas-Phase Pentaalanine: Divalent Ions Restructure the Complex

    NARCIS (Netherlands)

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

    2013-01-01

    Ion-neutral complexes of pentaalalanine with several singly- and doubly charged metal ions are examined using conformation analysis by infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) computations. The infrared spectroscopy in the 1500-1800 cm(-1) region

  6. Femtosecond Laser Post-Processing of Metal Parts Produced by Laser Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Mingareev Ilya

    2013-11-01

    Full Text Available High-repetition rate femtosecond laser radiation was utilized to improve surface quality of metal parts manufactured by laser additive techniques. This novel approach can be used to postprocess parts made of heat-sensitive materials, and to attain the designed net shape with micrometer precision.

  7. Differentiation of cyclosporin A from isocyclosporin A by liquid chromatography/electrospray ionization mass spectrometry with post-column addition of divalent metal salt.

    Science.gov (United States)

    Cirigliano, Adriana M; Cabrera, Gabriela M

    2014-03-15

    Cyclosporin A (CsA) rearranges to its isomer isocyclosporin A (isoCsA) upon acid hydrolysis and also during ionization in the ion source of the mass spectrometer. It has been reported that both compounds could not be differentiated by tandem mass spectrometry (MS/MS) using atmospheric pressure ionization (API) sources and ambiguously differentiated by using other sources. In order to analyze these compounds which are common fungal metabolites, it is relevant to develop a simple method for their differentiation. CsA and isoCsA were analyzed by liquid chromatography/mass spectrometry (LC/MS) with post-column addition of metal ion solutions in a quadrupole time-of-flight instrument equipped with an electrospray ionization (ESI) source. Mass spectra of CsA obtained upon post-column addition of solutions of Ca(II), Cu(II) and Zn(II) showed complexes between cyclosporin and the metal, including [2CsA + Me](2+) and [CsA-H + Me](+). These complexes were not observed in the spectra of isoCsA. The same results were observed at different metal concentrations. Differentiation via metal complexation in positive ion mode LC/ESI-MS was performed to simultaneously distinguish CsA and its isomer isoCsA. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Recent Trend and Applications on Metal Additive Manufacturing Technology : A Review

    OpenAIRE

    京極, 秀樹

    2015-01-01

    In this paper, the recent trend and applications on metal additive manufacturing technologies are reviewed. Recently, additive manufacturing technologies are paid great attention especially in the aerospace, automotive, and medical industries because of the possibility to manufacture lighter structures to reduce weight, complex high-performance parts, and so on. Therefore, a national project was launched by the Japanese government in April 2014 to develop the innovative 3D printers with elect...

  9. Antibacterial, anthelmintic and antioxidant activity of Argyreia elliptica extracts: Activity enhancement by the addition of metal salts

    Directory of Open Access Journals (Sweden)

    M K Prashanth

    2013-05-01

    Full Text Available Summary. Argyreia elliptica extracts were prepared with solvents at different polarity (petroleum ether, chloroform, ethyl acetate and methanol and evaluate their antibacterial, anthelmintic and antioxidant properties first time. An antioxidant activity was analyzed using different in vitro tests namely 2,2-diphenyl-1-picrylhydrazyl (DPPH and superoxide radical scavenging methods. Quantitative determination of phenols was carried out using spectrophotometric methods. In addition, the extracts were screened for their biological activity in absence and in presence of metal salts [Fe(III and Zn(II] ions. Results indicate that, the tested bacterial strains were most sensitive to the chloroform (CE and methanol extract (ME. Ethyl acetate (EA, CE and ME extracts showed potent radical scavenging activity. CE and ME extracts showed the highest total phenolic content and its enhanced anthelmintic and antioxidant activities were found in Fe(III combination. The extracts-Zn(II ion combination showed enhanced antibacterial activity against tested bacterial strains compare to the extracts alone.Industrial relevance. Herbal medicines have gained increasing attention worldwide for the treatment of various diseases because of their effectiveness and small side effects as compared to synthetic drugs. In general, the essential trace elements have been found to possess a very important role in biological system and also therapeutic activity depends on some trace elements. The present research reports the phytochemical screening of Argyrea elliptica leaves extracts. The antibacterial, anthilmentic and in vitro antioxidant activity activity of extracts and its metal salt combination was studied. The results scientifically establish the efficacy of the plant extracts and its metal salt combination as antibacterial, anthilmentic and antioxidant agents.Keywords. Argyreia elliptica; Antioxidant; Antibacterial activity; Total phenolic content.

  10. The Characteristics Of The Direct Metal Ion Beam Source And Its Applications (indium Tin Oxide)

    CERN Document Server

    Kim, D

    2001-01-01

    It is well known that thin film properties depends on its microstructures and the surface mobility is most important parameters to consider microstructures and to obtain high quality thin films. Thus, currently ion beam based deposition which can control surface mobility with kinetic energy of auxiliary gas ion investigated intensively. Recently we developed the DMIBD system which can control ion beam energy precisely under 500Ev and also ion beam flux, independently. In this work, the optimum process parameters of DMIBD such as secondary ion yields, ion/atom arrival ratios, ion energy spread, and deposition rates for various metal targets were measured as functions of Cs+ ion bombarding energy, Cs+ ion dose, and secondary ion beam energy, respectively. From the results, the secondary ion yields for C,Al,Si,Cu,Ta, and W were about 20% and the ion energy spread also less than 10% regardless of the ion beam energy. In order to investigated the effect of secondary ion beam energy on the thin film properties such...

  11. No Giant Two-Ion Anisotropy in the Heavy-Rare-Earth Metals

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1976-01-01

    A new Bose-operator expansion of tensor operators is applied to the heavy-rare-earth metals. The Er data for the cone phase have been analyzed successfully with single-ion anisotropy and isotropic exchange interaction. The Tb data can be understood on the same basis. The previously found large two......-ion anisotropy was due to an inadequate treatment of the large single-ion anisotropy leading to an incorrect expression for the spin-wave energy....

  12. 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

  13. Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

    Science.gov (United States)

    Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

    2016-05-01

    Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic

  14. Improved thermal stability of lithium ion battery by using cresyl diphenyl phosphate as an electrolyte additive

    Science.gov (United States)

    Wang, Qingsong; Ping, Ping; Sun, Jinhua; Chen, Chunhua

    To enhance the safety of lithium ion battery, cresyl diphenyl phosphate (CDP) is explored as an additive in 1.0 M LiPF 6/ethylene carbonate (EC) + diethyl carbonate (DEC) (1:1 wt.). The electrochemical performances of LiCoO 2/CDP-electrolyte/C cells are tested. At the thermal aspect, the thermal stability of the electrolyte with CDP is detected firstly by using a C80 micro-calorimeter, and then the charged LiCoO 2/CDP-electrolyte/C cells are disassembled and wrapped to detect the thermal behaviors. The results indicate that CDP-containing electrolyte enhances the thermal stabilities of electrolyte and lithium ion battery, and the electrochemical performances of LiCoO 2/CDP-electrolyte/C cell become slightly worse by using CDP in the electrolyte. Furthermore, the cell with 10% (wt.) CDP-containing electrolyte shows better cycle efficiency than that of other CDP-containing electrolyte, such as containing 5% (wt.) CDP and 15% (wt.) CDP. This maybe because that the mass ratio between CDP and electrolyte is close to the reaction stoichiometric ratio in the 10% (wt.) CDP-containing electrolyte, where stable solid electrolyte interphase (SEI) is formed. Therefore, 10% CDP-containing electrolyte improves the safety of lithium ion battery and keeps its electrochemical performance.

  15. Removal of toxic heavy metal ions in runoffs by modified alfalfa and juniper

    Science.gov (United States)

    J.S. Han; J.K. Park; S.H. Min

    2000-01-01

    A series of batch isotherm tests was performed with alfalfa and juniper fibers to evaluate the effectiveness in filtering toxic heavy metals from stormwater. The adsorption of the heavy metal ions on the alfalfa and juniper fibers was strongly dependent on the equilibrium pH value of the solution. The change in sorption rate over time showed that two different sorption...

  16. Effect of surface modification of microfiltration membrane on capture of toxic heavy metal ions.

    Science.gov (United States)

    Madaeni, Sayed Siavash; Heidary, Farhad

    2012-01-01

    A novel complexing membrane containing 8-hydroxyquinoline groups was used for the removal of heavy metal ions (Cd2+ and Ni2+) from aqueous solution. The functionalized membranes were characterized by FTIR-ATR, SEM and EDAX for the presence of functional groups, the physical structure of the membranes and the analysis of the particles deposited on the membrane, respectively. The influence of 8-hydroxyquinoline concentration, feed concentration, pH and temperature of the solution on capture capability was studied. The modified membrane showed a higher affinity to Cd2+ cations than to Ni2+. The metal ion rejection was increased with an increase in concentration of 8-hydroxyquinoline from 0.5 to 2.0 wt%. However at a ligand concentration higher than 2.0 wt%, no significant change was observed in the metal rejection. The experimental results revealed that the metal rejection was decreased with an increase in metal ion concentration in the feed. Moreover the rejection depended on feed pH and is higher for elevated pH. By changing the temperature in the range of 23-28 degrees C, no considerable effect on metal rejection was observed. However, a higher temperature resulted in a decline in metal rejection. For filtration of a mixture of the two metal ions, the retention was similar to that of the single cations, i.e. Cd > Ni but with smaller absolute rejections.

  17. Interactions between metal ions and biogeo-surfaces in soil and water

    NARCIS (Netherlands)

    Weng, L.

    2002-01-01

    To provide the basis for an improved quantitative risk assessment of heavy metals in the environment, the interactions between the metal ions and the biogeo-surfaces in soil and water were studied using both experimental and modelling approaches.The Donnan membrane technique was developed and optimi

  18. A QICAR Model for Metal Ion Toxicity Established via PLS Method

    Institute of Scientific and Technical Information of China (English)

    LI Yu; JIANG Long; LI Xiao-li; HU Yan; WEN Jing-ya

    2013-01-01

    The partial least squares(PLS) method was employed to establish a quantitative ion characteristics-activity relationship(QICAR) model for metal ion toxicity(EC50 of 15 metal ions).The ion characteristics included AN(the atomic number),AIP(the change in ionization potential,eV),Xm(the electronegativity,eV),AW(the atomic weight),Xm2r(the covalent index),△E0(the absolute difference between electrochemical potential of the ion and that of its first stable reduced state,eV),│lgKoH│(the absolute value of the lg of the first hydrolysis constant),AR(the atomic radius,nm),AR/AW(the ratio between atomic radius and atomic weight) and σp(the softness index) selected based on relative correlation analysis.The simulated and tested(with the other four metals) efficiency coefficients of the model are 0.88 and 0.96,respectively.The information revealed from the QICAR model indicates that the value of the metal ion toxicity was positively correlated with variables AN,△IP,Xm,AW and Xm2r; negatively correlated with variables △E0,│lgKoH│,AR/AW,AR and σp,and ion characteristics AE0,Xm,σp and Xm2r were found to contribute more to the toxicity of metal ions via the accurate analysis method provided by PLS.The model could be used to predict the toxicity of the target metals and preliminary to assess combined pollution and environmental risk for heavy metals in the environments.

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

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Jeeshan; Tripathi, Bijay P.; Saxena, Arunima; Shahi, Vinod K. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujarat (India)

    2007-08-01

    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{sup -} 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{sup +} 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. (author)

  20. 18-Electron rule inspired Zintl-like ions composed of all transition metals.

    Science.gov (United States)

    Zhou, Jian; Giri, Santanab; Jena, Purusottam

    2014-10-07

    Zintl phase compounds constitute a unique class of compounds composed of metal cations and covalently bonded multiply charged cluster anions. Potential applications of these materials in solution chemistry and thermoelectric materials have given rise to renewed interest in the search for new Zintl ions. Up to now these ions have been mostly composed of group 13, 14, and 15 post-transition metal elements and no Zintl ions composed of all transition metal elements are known. Using gradient corrected density functional theory we show that the 18-electron rule can be applied to design a new class of Zintl-like ions composed of all transition metal atoms. We demonstrate this possibility by using Ti@Au12(2-) and Ni@Au6(2-) di-anions as examples of Zintl-like ions. Predictive capability of our approach is demonstrated by showing that FeH6(4-) in an already synthesized complex metal hydride, Mg2FeH6, is a Zintl-like ion, satisfying the 18-electron rule. We also show that novel Zintl phase compounds can be formed by using all transition metal Zintl-like ions as building blocks. For example, a two-dimensional periodic structure of Na2[Ti@Au12] is semiconducting and nonmagnetic while a one-dimensional periodic structure of Mg[Ti@Au12] is metallic and ferromagnetic. Our results open the door to the design and synthesis of a new class of Zintl-like ions and compounds with potential for applications.

  1. Electrolyte additive enabled fast charging and stable cycling lithium metal batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Engelhard, Mark H.; Mei, Donghai; Jiao, Shuhong; Polzin, Bryant J.; Zhang, Ji-Guang; Xu, Wu

    2017-03-01

    Lithium (Li) metal battery is an attractive energy storage system owing to the ultrahigh specific capacity and the lowest redox potential of Li metal anode. However, safety concern associated with dendrite growth and limited cycle life especially at a high charge current density are two critical challenges hindering the practical applications of rechargeable Li metal batteries. Here, we report for the first time that an optimal amount (0.05 M) of LiPF6 as additive in the LiTFSI-LiBOB dual-salt/carbonate-based electrolyte can significantly enhance the charging capability and the long-term cycle life of Li metal batteries with a moderately high cathode loading of 1.75 mAh cm-2. Unprecedented stable-cycling (97.1% capacity retention after 500 cycles) along with very limited increase in electrode over-potential has been achieved at a high current density of 1.75 mA cm-2. This unparalleled fast charging and stable cycling performance is contributed from both the stabilized Al cathode current collector, and, more importantly, the robust and conductive SEI layer formed on Li metal anode in the presence of the LiPF6 additive.

  2. Alkali Metal Halide Salts as Interface Additives to Fabricate Hysteresis-Free Hybrid Perovskite-Based Photovoltaic Devices.

    Science.gov (United States)

    Wang, Lili; Moghe, Dhanashree; Hafezian, Soroush; Chen, Pei; Young, Margaret; Elinski, Mark; Martinu, Ludvik; Kéna-Cohen, Stéphane; Lunt, Richard R

    2016-09-07

    A new method was developed for doping and fabricating hysteresis-free hybrid perovskite-based photovoltaic devices by using alkali metal halide salts as interface layer additives. Such salt layers introduced at the perovskite interface can provide excessive halide ions to fill vacancies formed during the deposition and annealing process. A range of solution-processed halide salts were investigated. The highest performance of methylammonium lead mixed-halide perovskite device was achieved with a NaI interlayer and showed a power conversion efficiency of 12.6% and a hysteresis of less than 2%. This represents a 90% improvement compared to control devices without this salt layer. Through depth-resolved mass spectrometry, optical modeling, and photoluminescence spectroscopy, this enhancement is attributed to the reduction of iodide vacancies, passivation of grain boundaries, and improved hole extraction. Our approach ultimately provides an alternative and facile route to high-performance and hysteresis-free perovskite solar cells.

  3. Crystal phase competition by addition of a second metal cation in solid solution metal-organic frameworks.

    Science.gov (United States)

    Castillo-Blas, C; Snejko, N; de la Peña-O'Shea, V A; Gallardo, J; Gutiérrez-Puebla, E; Monge, M A; Gándara, F

    2016-03-14

    Herein we report a synthetic study focused on the preparation of solid-solution metal-organic frameworks, MOFs, with the use of two kinds of linkers. In particular, we have explored the system composed by zinc, cobalt, 1,2,4-triazole and 4,4′-hexafluoroisopropylidenebisbenzoic acid (H2hfipbb). During this study, four new MOFs have been isolated, denoted TMPF-88 [M3(hfipbb)2(triazole)2(H2O)], TMPF-90 [M2(triazole)3(OCH2CH3)], TMPF-91 [M2(hfipbb)(triazole)2(H2O)] and TMPF-95 [M5(hfipbb)4(triazole)2(H2O)] (TMPF = transition metal polymeric framework, M = Zn, Co, or mixture of them). The study demonstrates that the addition of a second metal element during the MOF synthesis has a major effect in the formation of new phases, even at very high Zn/Co metal ratios. Furthermore, we show that during the MOF formation reaction, there is a competition among different crystal phases, where kinetically favoured phases of various compositions crystallize in short reaction times, precluding the formation of the pure solid-solution phases of other energetically more stable MOFs.

  4. Engineering Short Preorganized Peptide Sequences for Metal Ion Coordination: Copper(II) a Case Study.

    Science.gov (United States)

    Lima, L M P; Iranzo, O

    2016-01-01

    Peptides are multidentate chiral ligands capable of coordinating different metal ions. Nowadays, they can be obtained with high yield and purity, thanks to the advances on peptide/protein chemistry as well as in equipment (peptide synthesizers). Based on the identity and length of their amino acid sequences, peptides can present different degrees of flexibility and folding. Although short peptide sequences (ion coordination. Based on our experience, we present a general scheme for the design, synthesis, and characterization of these peptidic scaffolds and provide protocols for the study of their metal ion coordination properties.

  5. Photo-induced reduction of Noble metal ions to metal nanoparticles on tubular J-aggregates

    Directory of Open Access Journals (Sweden)

    Stefan Kirstein

    2006-01-01

    Full Text Available Palladium and silver nanoparticles are formed on the surface of tubular J-aggregates of an amphiphilic tetrachlorobenzimidacarbocyanine dye by reduction of the respective metal cations in aqueous solution. Upon addition of the palladium complex Na2PdCl4 to the aggregate solution, the absorption spectrum shows significant changes which is explained by partial destruction of the aggregates. Cryogenic transmission electron microscopy (cryo-TEM images show that the tubular J-aggregates are randomly covered by well-separated Pd nanoparticles of approximately 1–3 nm size. Larger particles and higher particle density along the aggregates are obtained when an auxiliary reducing agent is added to the solution. The presence of the metallic particles leads to efficient fluorescence quenching giving clear evidence for super quenching. In similar experiments using AgNO3, silver nanoparticles are grown which are larger in size but less dense distributed along the aggregates. At least in the case of the silver particles, the spontaneous formation of metal nanoparticles is assumed to be initiated by a photo-induced electron transfer process (PET.

  6. Fluid mechanics of additive manufacturing of metal objects by accretion of droplets – a survey

    Directory of Open Access Journals (Sweden)

    Tesař Václav

    2016-01-01

    Full Text Available Paper presents a survey of principles of additive manufacturing of metal objects by accretion of molten metal droplets, focusing on fluid-mechanical problems that deserve being investigated. The main problem is slowness of manufacturing due to necessarily small size of added droplets. Increase of droplet repetition rate calls for basic research of the phenomena that take place inside and around the droplets: ballistics of their flight, internal flowfield with heat and mass transfer, oscillation of surfaces, and the ways to elimination of satellite droplets.

  7. ADSORPTION SELECTIVITY FOR Cu2+,Ni2+,Co2+IONS USING CROSSLINKING CHITOSAN RESINS IMPRINTED BY METAL IONS

    Institute of Scientific and Technical Information of China (English)

    HUANGWenqiang; HANLijun; 等

    1999-01-01

    Metal ion-imprintedly crosslinked chitosan resin 1 and resin 2 were prepared by the use of Cu2+ and Ni2+ as template ions and glutaraldehyde as crosslinking agent,respectively,Through investigation on the adsorption capacties and binding constants for Cu2+,Ni2+ and Co2+ ions on chitosan resins,resin 1 and resin 2 exhibit the adsorption selectivity for the mixture solution of 1L1 Cu2+ and Ni2+ ions.The adsorption selectivity of metal ion-imprinted resins for their template ions in much higher than that of uncrosslinked chitosan resin.

  8. Experimental study of combustion characteristics of nanoscale metal and metal oxide additives in biofuel (ethanol

    Directory of Open Access Journals (Sweden)

    Peterson GP

    2011-01-01

    Full Text Available Abstract An experimental investigation of the combustion behavior of nano-aluminum (n-Al and nano-aluminum oxide (n-Al2O3 particles stably suspended in biofuel (ethanol as a secondary energy carrier was conducted. The heat of combustion (HoC was studied using a modified static bomb calorimeter system. Combustion element composition and surface morphology were evaluated using a SEM/EDS system. N-Al and n-Al2O3 particles of 50- and 36-nm diameters, respectively, were utilized in this investigation. Combustion experiments were performed with volume fractions of 1, 3, 5, 7, and 10% for n-Al, and 0.5, 1, 3, and 5% for n-Al2O3. The results indicate that the amount of heat released from ethanol combustion increases almost linearly with n-Al concentration. N-Al volume fractions of 1 and 3% did not show enhancement in the average volumetric HoC, but higher volume fractions of 5, 7, and 10% increased the volumetric HoC by 5.82, 8.65, and 15.31%, respectively. N-Al2O3 and heavily passivated n-Al additives did not participate in combustion reactively, and there was no contribution from Al2O3 to the HoC in the tests. A combustion model that utilized Chemical Equilibrium with Applications was conducted as well and was shown to be in good agreement with the experimental results.

  9. Removal of Heavy Metal Ions from Polluted Waters by Using of Low Cost Adsorbents: Review

    Directory of Open Access Journals (Sweden)

    M. Ghaedi

    2013-06-01

    Full Text Available Adsorption is a fundamental process in the physicochemical treatment of wastewaters which industries employ to reduce hazardous organic and inorganic wastes in effluents. In recent years the use of low-cost adsorbents has been widely investigated as a replacement for the currently costly methods of removing heavy metal ions from wastewater. It is well-known that cellulosic waste materials can be obtained and employed as cheap adsorbents and their performance to remove heavy metal ions can be affected upon chemical treatment. In this study, the use of some of low cost adsorbents for the removal of heavy metals from wastewater has been reviewed.

  10. Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate.

    Science.gov (United States)

    Rocha, J C; Toscano, I A; Burba, P

    1997-01-01

    Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich waters by ultrafiltration and a resin XAD 8 procedure. The HS-metal species studied were formed by complexation with Cd(II), Ni(II), Cu(II), Mn(II) and Pb(II) as a function of time and the ratio ions to HSs. The kinetics and reaction order of this exchange process were studied. At the beginning ( Pb > Mn > Ni > Cd. The required metal determinations were carried out by atomic absorption spectrometry.

  11. Synthesis, Characterization and Metal Ion Detection of Novel Fluoroionophores Based on Heterocyclic Substituted Alanines

    Directory of Open Access Journals (Sweden)

    M. Manuela M Raposo

    2007-10-01

    Full Text Available The synthesis of new fluorescent probes containing the thiophene andbenzoxazole moieties combined with an alanine residue is described. The resulting highlyfluorescent heterocyclic alanine derivatives respond via a quenching effect, withparamagnetic Cu(II and Ni(II metal ions and with diamagnetic Hg(II, as shown by theabsorption and steady-state fluorescence spectroscopy studies. The formation ofmononuclear or dinuclear metal complexes was postulated based on the presence of thefree carboxylic acid as binding site and also with the interaction with the donor atoms inthe chromophore. Interaction with other important biological metal ions such as Zn(II,Ca(II and Na(I was also explored.

  12. Sub-millimeter Spectroscopy of Astrophysically Important Molecules and Ions: Metal Hydrides, Halides, and Cyanides

    Science.gov (United States)

    Ziurys, L. M.; Flory, M. A.; Halfen, D. T.

    2006-01-01

    With the advent of SOFIA, Herschel, and SAFIR, new wavelength regions will become routinely accessible for astronomical spectroscopy, particularly at submm frequencies (0.5-1.1 THz). Molecular emission dominates the spectra of dense interstellar gas at these wavelengths. Because heterodyne detectors are major instruments of these missions, accurate knowledge of transition frequencies is crucial for their success. The Ziurys spectroscopy laboratory has been focusing on the measurement of the pure rotational transitions of astrophysically important molecules in the sub-mm regime. Of particular interest have been metal hydride species and their ions, as well as metal halides and cyanides. A new avenue of study has included metal bearing molecular ions.

  13. Removal of heavy metal ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2015-01-01

    Heavy metals are a common pollutant found in various industrial effluents. They are often encountered in mining operations and acid mine drainage. The heavy metals are highly toxic and are non-biodegradable, therefore they must be removed from the polluted streams in order to meet increasingly stringent environmental quality standards. Removal of heavy metals can be accomplished by a variety of techniques. Conventional methods typically involve the use of processes such as coag...

  14. Removal of heavy metal ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2015-01-01

    Heavy metals are a common pollutant found in various industrial effluents. They are often encountered in mining operations and acid mine drainage. The heavy metals are highly toxic and are non-biodegradable, therefore they must be removed from the polluted streams in order to meet increasingly stringent environmental quality standards. Removal of heavy metals can be accomplished by a variety of techniques. Conventional methods typically involve the use of processes such as coag...

  15. Heavy metal ions in wines: meta-analysis of target hazard quotients reveal health risks

    Directory of Open Access Journals (Sweden)

    Petróczi Andrea

    2008-10-01

    Full Text Available Abstract Background Metal ions such as iron and copper are among the key nutrients that must be provided by dietary sources. Numerous foodstuffs have been evaluated for their contributions to the recommended daily allowance both to guide for satisfactory intake and also to prevent over exposure. In the case of heavy metal ions, the focus is often on exposure to potentially toxic levels of ions such as lead and mercury. The aim of this study is to determine target hazard quotients (THQ from literature reports giving empirical levels of metal ions in table wines using the reference upper safe limit value. Contributions to the THQ value were calculated for seven metal ions along with total values for each wine. Results The THQ values were determined as ranges from previously reported ranges of metal ion concentrations and were frequently concerningly high. Apart from the wines selected from Italy, Brazil and Argentina, all other wines exhibited THQ values significantly greater than one indicating levels of risk. The levels of vanadium, copper and manganese had the highest impact on THQ measures. Typical potential maximum THQ values ranged from 50 to 200 with Hungarian and Slovakian wines reaching 300. THQ values for a sample of red and white wines were high for both having values ranging from 30 to 80 for females based on a 250 mL glass per day. Conclusion The THQ values calculated are concerning in that they are mainly above the safe level of THQ

  16. Characterization of surfactant effects on the visible spectroscopy of lanthanide metal ion-triphenylmethane dye complexes

    Energy Technology Data Exchange (ETDEWEB)

    Klopf, G.J.

    1985-01-01

    To better define the mechanism responsible for sensitization, the interactions of representative cationic, anionic, and nonionic surfactants with several lanthanide metal ion-triphenylmethane dye complexes, particularly the gadolinium (Gd/sup +3/)-Chromeazurol S (CAS) complex, were characterized. Only cationic surfactants induced sensitization when added to the Gd/sup +3/-CAS complex. Sensitization induced by cetylpyridinium chloride (CPC) occurred at submicellar concentrations and was attributed to the formation of a 1:2:4 Gd/sup +3/-CAS-CPC ternary complex. Additional ternary complexes evidently form if excess CAS is present. Mechanisms are proposed for the sensitization of the reaction by quaternary compounds and by anionic surfactants. Although both micellar and submicellar concentrations were considered, adding the nonionic surfactant Triton X-100 to the Gd/sup +3/-CAS complex had little effect.

  17. Antimicrobial effects of metal ions (Ag+, Cu2+, Zn2+) in hydroxyapatite.

    Science.gov (United States)

    Kim, T N; Feng, Q L; Kim, J O; Wu, J; Wang, H; Chen, G C; Cui, F Z

    1998-03-01

    The antimicrobial ceramics (AC) based on hydroxyapatite (HA) were made in a wet chemical process with additions of AgNO3, Cu(NO3)2. 3H2O and Zn(NO3)2. 6H2O. The ACs were composed of metal-ion substituted hydroxyapatite and nitrate-apatite, which was identified by X-ray diffraction. The viable count and turbidity measurement was adopted to observe the antimicrobial effects of the various ACs. The aerobic Escherichia coli was used in the study. An obvious antimicrobial effect against E. coli was observed in Ag+ AC. In contrast to Ag+ AC, it was difficult to ascertain any bactericidal effect in the case of Cu2+ and Zn2+ AC. The bactericidal effect of Ag+ was observed using a dialysis tube experiment. This suggests that Ag+ dissolved out and reacted with E. coli, thus inhibiting its growth.

  18. Aggregation and metal ion extraction properties of novel, silicon-substituted alkylenediphosphonic acids.

    Energy Technology Data Exchange (ETDEWEB)

    McAlister, D. R.; Dietz, M. L.; Chiarizia, R.; Herlinger, A. W.

    2001-05-10

    In conjunction with efforts to develop novel actinide extractants exhibiting solubility in supercritical carbon dioxide, the effect of adding silicon-based functionalities to diphosphonic acids has been investigated. Specifically, a series of silyl-substituted diphosphonic acids has been prepared and characterized, and their aggregation and metal ion extraction properties compared with alkyl-substituted diphosphonic acids, reagents previously demonstrated to be effective extractants of actinides from acidic aqueous media into various organic solvents. In addition, the influence of the number of methylene groups bridging the phosphorus atoms of the diphosphonic acids on their extraction behavior has been investigated. Variations in the extraction behavior of the compounds arising from differences in the number of bridging methylene groups have been shown to be attributable to a combination of factors, in particular, the aggregation state of the ligand, the size of the chelate rings formed upon complexation, the basicity of the phosphoryl group and the relative acidities of the ligands.

  19. Ultrahigh-current-density metal-ion implantation and diamondlike-hydrocarbon films for tribological applications

    Science.gov (United States)

    Wilbur, P. J.

    1993-09-01

    The metal-ion-implantation system used to implant metals into substrates are described. The metal vapor required for operation is supplied by drawing sufficient electron current from the plasma discharge to an anode-potential crucible so a solid, pure metal placed in the crucible will be heated to the point of vaporization. The ion-producing, plasma discharge is initiated within a graphite-ion-source body, which operates at high temperature, by using an argon flow that is turned off once the metal vapor is present. Extraction of ion beams several cm in diameter at current densities ranging to several hundred micro-A/sq cm on a target 50 cm downstream of the ion source were demonstrated using Mg, Ag, Cr, Cu, Si, Ti, V, B, and Zr. These metals were implanted into over 100 substrates (discs, pins, flats, wires). A model describing thermal stresses induced in materials (e.g. ceramic plates) during high-current-density implantation is presented. Tribological and microstructural characteristics of iron and 304-stainless-steel samples implanted with Ti or B are examined. Diamondlike-hydrocarbon coatings were applied to steel surfaces and found to exhibit good tribological performance.

  20. Structure simulation into a lamellar supramolecular network and calculation of the metal ions/ligands ratio

    Directory of Open Access Journals (Sweden)

    Visa Aurelia

    2012-08-01

    Full Text Available Abstract Background Research interest in phosphonates metal organic frameworks (MOF has increased extremely in the last two decades, because of theirs fascinating and complex topology and structural flexibility. In this paper we present a mathematical model for ligand/metal ion ratio of an octahedral (Oh network of cobalt vinylphosphonate (Co(vP·H2O. Results A recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (Oh network Co(vP·H2O, has been deducted by building the 3D network step by step using HyperChem 7.52 package. The mathematical relationship has been validated using X ray analysis, experimental thermogravimetric and elemental analysis data. Conclusions Based on deducted recurrence relationship, we can conclude prior to perform X ray analysis, that in the case of a thermogravimetric analysis pointing a ratio between the number of metal ions and ligands number around 1, the 3D network will have a central metal ion that corresponds to a single ligand. This relation is valid for every type of supramolecular network with divalent metal central ion Oh coordinated and bring valuable information with low effort and cost.