Antimicrobial and water-triggered release characteristics of a copper sulfate-polyvinyl acetate adhesive composite

NASA Astrophysics Data System (ADS)

De Jesus, A. P. O.; Roxas-Villanueva, R. M. L.; Herrera, M. U.

2017-05-01

Water-triggered release of antimicrobial solutions is advantageous in inhibiting the growth of bacteria and fungi in moist and wet environments. In this study, we fabricated a composite, by mixing polyvinyl acetate adhesive with copper sulfate solution, which exhibits antimicrobial activities against bacteria. Polyvinyl acetate adhesive serves as the binder and water soluble substance while copper sulfate serves as the antimicrobial agent. The composite was coated in an acetate film and air-dried. To monitor the rate of release of copper ions, the composite was submerged in water and the conductivity was measured. The conductivity saturation time was determined. The composite showed antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive).

Fragmentation of copper current collectors in Li-ion batteries during spherical indentation

NASA Astrophysics Data System (ADS)

Wang, Hsin; Watkins, Thomas R.; Simunovic, Srdjan; Bingham, Philip R.; Allu, Srikanth; Turner, John A.

2017-10-01

Large, areal, brittle fracture of copper current collector foils has been observed by 3D x-ray computed tomography (XCT) of a spherically indented Li-ion cell. This fracture is hidden and non-catastrophic to a degree because the graphite layers deform plastically, and hold the materials together so that the cracks in the foils cannot be seen under optical and electron microscopy. The cracking of copper foils could not be immediately confirmed when the cell is opened for post-mortem examination. However, 3D XCT on the indented cell reveals ;mud cracks; within the copper layer and an X-ray radiograph on a single foil of the Cu anode shows clearly that the copper foil has broken into multiple pieces. This failure mode of anodes in Li-ion cell has very important implications on the behavior of Li-ion cells under mechanical abuse conditions. The fragmentation of current collectors in the anode must be taken into consideration for the electrochemical responses which may lead to capacity loss and affect thermal runaway behavior of the cells.

Modeling MIC copper release from drinking water pipes.

PubMed

Pizarro, Gonzalo E; Vargas, Ignacio T; Pastén, Pablo A; Calle, Gustavo R

2014-06-01

Copper is used for household drinking water distribution systems given its physical and chemical properties that make it resistant to corrosion. However, there is evidence that, under certain conditions, it can corrode and release unsafe concentrations of copper to the water. Research on drinking water copper pipes has developed conceptual models that include several physical-chemical mechanisms. Nevertheless, there is still a necessity for the development of mathematical models of this phenomenon, which consider the interaction among physical-chemical processes at different spatial scales. We developed a conceptual and a mathematical model that reproduces the main processes in copper release from copper pipes subject to stagnation and flow cycles, and corrosion is associated with biofilm growth on the surface of the pipes. We discuss the influence of the reactive surface and the copper release curves observed. The modeling and experimental observations indicated that after 10h stagnation, the main concentration of copper is located close to the surface of the pipe. This copper is associated with the reactive surface, which acts as a reservoir of labile copper. Thus, for pipes with the presence of biofilm the complexation of copper with the biomass and the hydrodynamics are the main mechanisms for copper release. Copyright © 2013 Elsevier B.V. All rights reserved.

Fragmentation of copper current collectors in Li-ion batteries during spherical indentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hsin; Watkins, Thomas R.; Simunovic, Srdjan

Large, areal, brittle fracture of copper current collector foils was observed by 3D x-ray computed tomography (XCT) of a spherically indented Li-ion cell. This fracture was hidden and non-catastrophic to a degree because the graphite layers deformed plastically, and held the materials together so that the cracks in the foils could not be seen under optical and electron microscopy. 3D XCT on the indented cell showed “mud cracks” within the copper layer. The cracking of copper foils could not be immediately confirmed when the cell was opened for post-mortem examination. However, an X-ray radiograph on a single foil of themore » Cu anode showed clearly that the copper foil had broken into multiple pieces similar to the brittle cracking of a ceramic under indentation. This new failure mode of anodes on Li-ion cell has very important implications on the behavior of Li-ion cells under mechanical abuse conditions. Furthermore, the fragmentation of current collectors in the anode must be taken into consideration for the electrochemical responses which may lead to capacity loss and affect thermal runaway behavior of the cells.« less

Fragmentation of copper current collectors in Li-ion batteries during spherical indentation

DOE PAGES

Wang, Hsin; Watkins, Thomas R.; Simunovic, Srdjan; ...

2017-08-29

Large, areal, brittle fracture of copper current collector foils was observed by 3D x-ray computed tomography (XCT) of a spherically indented Li-ion cell. This fracture was hidden and non-catastrophic to a degree because the graphite layers deformed plastically, and held the materials together so that the cracks in the foils could not be seen under optical and electron microscopy. 3D XCT on the indented cell showed “mud cracks” within the copper layer. The cracking of copper foils could not be immediately confirmed when the cell was opened for post-mortem examination. However, an X-ray radiograph on a single foil of themore » Cu anode showed clearly that the copper foil had broken into multiple pieces similar to the brittle cracking of a ceramic under indentation. This new failure mode of anodes on Li-ion cell has very important implications on the behavior of Li-ion cells under mechanical abuse conditions. Furthermore, the fragmentation of current collectors in the anode must be taken into consideration for the electrochemical responses which may lead to capacity loss and affect thermal runaway behavior of the cells.« less

Nickel Ion Release from Three Types of Nickel-titanium-based Orthodontic Archwires in the As-received State and After Oral Simulation

PubMed Central

Ramazanzadeh, Barat Ali; Ahrari, Farzaneh; Sabzevari, Berahman; Habibi, Samaneh

2014-01-01

Background and aims. This study aimed to investigate release of nickel ion from three types of nickel-titanium-based wires in the as-received state and after immersion in a simulated oral environment. Materials and methods. Forty specimens from each of the single-strand NiTi (Rematitan "Lite"), multi-strand NiTi (SPEED Supercable) and Copper NiTi (Damon Copper NiTi) were selected. Twenty specimens from each type were used in the as-received state and the others were kept in deflected state at 37ºC for 2 months followed by autoclave sterilization. The as-received and recycled wire specimens were immersed in glass bottles containing 1.8 mL of artificial saliva for 28 days and the amount of nickel ion released into the electrolyte was determined using atomic absorption spectrophotometry. Results. The single-strand NiTi released the highest quantity of nickel ion in the as-received state and the multi-strand NiTi showed the highest ion release after oral simulation. The quantity of nickelion released from Damon Copper NiTi was the lowest in both conditions. Oral simulation followed by sterilization did not have a significant influence on nickel ion release from multi-strand NiTi and Damon Copper NiTi wires, but single-strand NiTi released statistically lower quantities of nickel ion after oral simulation. Conclusion. The multi-strand nature of Supercable did not enhance the potential of corrosion after immersion in the simulated oral environment. In vitro use of nickel-titanium-based archwires followed by sterilization did not significantly increase the amount of nickel ion released from these wires. PMID:25093049

Best Practices for Controlling Lead and Copper Release

EPA Science Inventory

Presentation draft, covering summary of current state-of-the-art knowledge for the best treatment strategies for minimizing lead release and controlling copper release. The presentation is intended to aid with compliance with the Lead and Copper Rule, but also provide a guide to...

Comparison and distribution of copper oxide nanoparticles and copper ions in activated sludge reactors.

PubMed

Zhang, Dongqing; Trzcinski, Antoine P; Oh, Hyun-Suk; Chew, Evelyn; Tan, Soon Keat; Ng, Wun Jern; Liu, Yu

2017-05-12

Copper oxide nanoparticles (CuO NPs) are being increasingly applied in the industry which results inevitably in the release of these materials into the hydrosphere. In this study, simulated waste-activated sludge experiments were conducted to investigate the effects of Copper Oxide NPs at concentrations of 0.1, 1, 10 and 50 mg/L and to compare it with its ionic counterpart (CuSO 4 ). It was found that 0.1 mg/L of CuO NPs had negligible effects on Chemical Oxygen Demand (COD) and ammonia removal. However, the presence of 1, 10 and 50 mg/L of CuO NPs decreased COD removal from 78.7% to 77%, 52.1% and 39.2%, respectively (P < 0.05). The corresponding effluent ammonium (NH 4 -N) concentration increased from 14.9 mg/L to 18, 25.1 and 30.8 mg/L, respectively. Under equal Cu concentration, copper ions were more toxic towards microorganisms compared to CuO NPs. CuO NPs were removed effectively (72-93.2%) from wastewater due to a greater biosorption capacity of CuO NPs onto activated sludge, compared to the copper ions (55.1-83.4%). The SEM images clearly showed the accumulation and adsorption of CuO NPs onto activated sludge. The decrease in Live/dead ratio after 5 h of exposure of CuO NPs and Cu 2+ indicated the loss of cell viability in sludge flocs.

Oxidation of nitroxyl anion to nitric oxide by copper ions

PubMed Central

Nelli, Silvia; Hillen, Mark; Buyukafsar, Kansu; Martin, William

2000-01-01

This study made use of a nitric oxide-sensitive electrode to examine possible means of generating nitric oxide from nitroxyl anion (NO−) released upon the decomposition of Angeli's salt. Our results show that copper ions (from CuSO4) catalyze the rapid and efficient oxidation of nitroxyl to nitric oxide. Indeed, the concentrations of copper required to do so (0.1–100 μM) are roughly 100-times lower than those required to generate equivalent amounts of nitric oxide from S-nitroso-N-acetyl-D,L-penicillamine (SNAP). Experiments with ascorbate (1 mM), which reduces Cu2+ ions to Cu+, and with the Cu2+ chelators, EDTA and cuprizone, and the Cu+ chelator, neocuproine, each at 1 mM, suggest that the oxidation is catalyzed by copper ions in both valency states. Some compounds containing other transition metals, i.e. methaemoglobin, ferricytochrome c and Mn(III)TMPyP, were much less efficient than CuSO4 in catalyzing the formation of nitric oxide from nitroxyl, while FeSO4, FeCl3, MnCl2, and ZnSO4 were inactive. Of the copper containing enzymes examined, Cu-Zn superoxide dismutase and ceruloplasmin were weak generators of nitric oxide from nitroxyl, even at concentrations (2500 and 30 u ml−1, respectively) vastly greater than are present endogenously. Two others, ascorbate oxidase (10 u ml−1) and tyrosinase (250 u ml−1) were inactive. Our findings suggest that a copper-containing enzyme may be responsible for the rapid oxidation of nitroxyl to nitric oxide by cells, but the identity of such an enzyme remains elusive. PMID:10991931

Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper-ion resistant bacteria

PubMed Central

Elguindi, Jutta; Moffitt, Stuart; Hasman, Henrik; Andrade, Cassandra; Raghavan, Srini; Rensing, Christopher

2013-01-01

The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by influx of copper ions into the cells but the exact mechanism is not fully understood. This study showed that the kinetics of contact-killing of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium used, and type of bacteria. We examined antibiotic- and copper-ion resistant strains of Escherichia coli and Enterococcus faecium isolated from pig farms following the use of copper sulfate as feed supplement. The results showed rapid killing of both copper-ion resistant E. coli and E. faecium strains when samples in rich medium were spread in a thin, moist layer on copper alloys with 85% or greater copper content. E. coli strains were rapidly killed under dry conditions while E. faecium strains were less affected. Electroplated copper surface corrosion rates were determined from electro-chemical polarization tests using the Stern-Geary method and revealed decreased corrosion rates with benzotriazole and thermal oxide coating. Copper-ion resistant E. coli and E. faecium cells suspended in 0.8% NaCl showed prolonged survival rates on electroplated copper surfaces with benzotriazole coating and thermal oxide coating compared to surfaces without anti-corrosion treatment. Control of surface corrosion affected the level of copper ion influx into bacterial cells which contributed directly to bacterial killing. PMID:21085951

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

PubMed

Mikulewicz, Marcin; Chojnacka, Katarzyna; Wołowiec, Paulina

2014-01-01

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

Decrease in cytotoxicity of copper-based intrauterine devices (IUD) pretreated with 6-mercaptopurine and pterin as biocompatible corrosion inhibitors.

PubMed

Alvarez, Florencia; Grillo, Claudiaa; Schilardi, Patricial; Rubert, Aldo; Benítez, Guillermo; Lorente, Carolina; de Mele, Mónica Fernández Lorenzo

2013-01-23

The copper intrauterine device (IUD) based its contraceptive action on the release of cupric ions from a copper wire. Immediately after the insertion, a burst release of copper ions occurs, which may be associated to a variety of side effects. 6-Mercaptopurine (6-MP) and pterin (PT) have been proposed as corrosion inhibitors to reduce this harmful release. Pretreatments with 1 × 10(-4) M 6-MP and 1 × 10(-4) M PT solutions with 1h and 3h immersion times were tested. Conventional electrochemical techniques, EDX and XPS analysis, and cytotoxicity assays with HeLa cell line were employed to investigate the corrosion behavior and biocompatibility of copper with and without treatments. Results showed that copper samples treated with PT and 6-MP solutions for 3 and 1 h, respectively, are more biocompatible than those without treatment. Besides, the treatment reduces the burst release effect of copper in simulated uterine solutions during the first week after the insertion. It was concluded that PT and 6-MP treatments are promising strategies able to reduce the side effects related to the "burst release" of copper-based IUD without altering the contraceptive action.

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

PubMed

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.

Release and detection of nanosized copper from a commercial antifouling paint.

PubMed

Adeleye, Adeyemi S; Oranu, Ekene A; Tao, Mengya; Keller, Arturo A

2016-10-01

One major concern with the use of antifouling paints is the release of its biocides (mainly copper and zinc) into natural waters, where they may exhibit toxicity to non-target organisms. While many studies have quantified the release of biocides from antifouling paints, very little is known about the physicochemical state of released copper. For proper risk assessment of antifouling paints, characterization of copper released into water is necessary because the physicochemical state determines the metal's environmental fate and effects. In this study, we monitored release of different fractions of copper (dissolved, nano, and bulk) from a commercial copper-based antifouling paint. Release from painted wood and aluminum mini-bars that were submerged in natural waters was monitored for 180 days. Leachates contained both dissolved and particulate copper species. X-ray diffraction and X-ray photoelectron spectroscopy were used to determine the chemical phase of particles in the leachate. The amount of copper released was strongly dependent on water salinity, painted surface, and paint drying time. The presence of nanosized Cu2O particles was confirmed in paint and its leachate using single-particle inductively coupled plasma-mass spectrometry and electron microscopy. Toxicity of paint leachate to a marine phytoplankton was also evaluated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessing the release of copper from nanocopper-treated and conventional copper-treated lumber into marine waters I: Concentrations and rates.

PubMed

Parks, Ashley N; Cantwell, Mark G; Katz, David R; Cashman, Michaela A; Luxton, Todd P; Ho, Kay T; Burgess, Robert M

2018-03-25

Little is known about the release of metal engineered nanomaterials (ENMs) from consumer goods, including lumber treated with micronized copper. Micronized copper is a recent form of antifouling wood preservative containing nanosized copper particles for use in pressure-treated lumber. The present study investigated the concentrations released and the release rate of total copper over the course of 133 d under freshwater, estuarine, and marine salinity conditions (0, 1, 10, and 30‰) for several commercially available pressure-treated lumbers: micronized copper azole (MCA) at 0.96 and 2.4 kg/m 3 , alkaline copper quaternary (ACQ) at 0.30 and 9.6 kg/m 3 , and chromated copper arsenate (CCA) at 40 kg/m 3 . Lumber was tested as blocks and as sawdust. Overall, copper was released from all treated lumber samples. Under leaching conditions, total release ranged from 2 to 55% of the measured copper originally in the lumber, with release rate constants from the blocks of 0.03 to 2.71 (units per day). Generally, measured release and modeled equilibrium concentrations were significantly higher in the estuarine conditions compared with freshwater or marine salinities, whereas rate constants showed very limited differences between salinities. Furthermore, organic carbon was released during the leaching and demonstrated a significant relationship with released copper concentrations as a function of salinity. The results indicate that copper is released into estuarine/marine waters from multiple wood treatments including lumber amended with nanoparticle-sized copper. Environ Toxicol Chem 2018;9999:1-13. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Release of copper-amended particles from micronized copper-pressure-treated wood during mechanical abrasion.

PubMed

Civardi, Chiara; Schlagenhauf, Lukas; Kaiser, Jean-Pierre; Hirsch, Cordula; Mucchino, Claudio; Wichser, Adrian; Wick, Peter; Schwarze, Francis W M R

2016-11-28

We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. Our results indicate that the abrasion of MCA-pressure-treated wood does not cause an additional release of nanoparticles from the unreacted copper (Cu) carbonate nanoparticles from of the MCA formulation. However, a small amount of released Cu was detected in the nanosized fraction of wood dust, which could penetrate the deep lungs. The acute cytotoxicity studies were performed on a human lung epithelial cell line and human macrophages derived from a monocytic cell line. These cell types are likely to encounter the released wood particles after inhalation. Our findings indicate that under the experimental conditions chosen, MCA does not pose a specific additional nano-risk, i.e. there is no additional release of nanoparticles and no specific nano-toxicity for lung epithelial cells and macrophages.

Ligand-Doped Copper Oxo-hydroxide Nanoparticles are Effective Antimicrobials

NASA Astrophysics Data System (ADS)

Bastos, Carlos A. P.; Faria, Nuno; Ivask, Angela; Bondarenko, Olesja M.; Kahru, Anne; Powell, Jonathan

2018-04-01

Bacterial resistance to antimicrobial therapies is an increasing clinical problem. This is as true for topical applications as it is for systemic therapy. Topically, copper ions may be effective and cheap antimicrobials that act through multiple pathways thereby limiting opportunities to bacteria for resistance. However, the chemistry of copper does not lend itself to facile formulations that will readily release copper ions at biologically compatible pHs. Here, we have developed nanoparticulate copper hydroxide adipate tartrate (CHAT) as a cheap, safe, and readily synthesised material that should enable antimicrobial copper ion release in an infected wound environment. First, we synthesised CHAT and showed that this had disperse aquated particle sizes of 2-5 nm and a mean zeta potential of - 40 mV. Next, when diluted into bacterial medium, CHAT demonstrated similar efficacy to copper chloride against Escherichia coli and Staphylococcus aureus, with dose-dependent activity occurring mostly around 12.5-50 mg/L of copper. Indeed, at these levels, CHAT very rapidly dissolved and, as confirmed by a bacterial copper biosensor, showed identical intracellular loading to copper ions derived from copper chloride. However, when formulated at 250 mg/L in a topically applied matrix, namely hydroxyethyl cellulose, the benefit of CHAT over copper chloride was apparent. The former yielded rapid sustained release of copper within the bactericidal range, but the copper chloride, which formed insoluble precipitates at such concentration and pH, achieved a maximum release of 10 ± 7 mg/L copper by 24 h. We provide a practical formulation for topical copper-based antimicrobial therapy. Further studies, especially in vivo, are merited.

Improved estimates of environmental copper release rates from antifouling products.

PubMed

Finnie, Alistair A

2006-01-01

The US Navy Dome method for measuring copper release rates from antifouling paint in-service on ships' hulls can be considered to be the most reliable indicator of environmental release rates. In this paper, the relationship between the apparent copper release rate and the environmental release rate is established for a number of antifouling coating types using data from a variety of available laboratory, field and calculation methods. Apart from a modified Dome method using panels, all laboratory, field and calculation methods significantly overestimate the environmental release rate of copper from antifouling coatings. The difference is greatest for self-polishing copolymer antifoulings (SPCs) and smallest for certain erodible/ablative antifoulings, where the ASTM/ISO standard and the CEPE calculation method are seen to typically overestimate environmental release rates by factors of about 10 and 4, respectively. Where ASTM/ISO or CEPE copper release rate data are used for environmental risk assessment or regulatory purposes, it is proposed that the release rate values should be divided by a correction factor to enable more reliable generic environmental risk assessments to be made. Using a conservative approach based on a realistic worst case and accounting for experimental uncertainty in the data that are currently available, proposed default correction factors for use with all paint types are 5.4 for the ASTM/ISO method and 2.9 for the CEPE calculation method. Further work is required to expand this data-set and refine the correction factors through correlation of laboratory measured and calculated copper release rates with the direct in situ environmental release rate for different antifouling paints under a range of environmental conditions.

ALKALINITY, PH, AND COPPER CORROSION BY-PRODUCT RELEASE

EPA Science Inventory

Contrary to expectations, higher bicarbonate concentrations exacerbate copper corrosion rates and by-product release. In fact, as illustrated by monitoring experiences of large utilities and by laboratory data, the concentration of copper corrosion by-products in drinking water i...

Biosorption of copper and lead ions by waste beer yeast.

PubMed

Han, Runping; Li, Hongkui; Li, Yanhu; Zhang, Jinghua; Xiao, Huijun; Shi, Jie

2006-10-11

Locally available waste beer yeast, a byproduct of brewing industry, was found to be a low cost and promising adsorbent for adsorbing copper and lead ions from wastewater. In this work, biosorption of copper and lead ions on waste beer yeast was investigated in batch mode. The equilibrium adsorptive quantity was determined to be a function of the solution pH, contact time, beer yeast concentration, salt concentration and initial concentration of copper and lead ions. The experimental results were fitted well to the Langmuir and Freundlich model isotherms. According to the parameters of Langmuir isotherm, the maximum biosorption capacities of copper and lead ions onto beer yeast were 0.0228 and 0.0277 mmol g(-1) at 293 K, respectively. The negative values of the standard free energy change (DeltaG degrees ) indicate spontaneous nature of the process. Competitive biosorption of two metal ions was investigated in terms of sorption quantity. The amount of one metal ion adsorbed onto unit weight of biosorbent (q(e)) decreased with increasing the competing metal ion concentration. The binding capacity for lead is more than for copper. Ion exchange is probably one of the main mechanism during adsorptive process.

Removal of Copper(II) Ions in Aqueous Solutions Using Tannin-Rich Plants as Natural Bio-Adsorbents

NASA Astrophysics Data System (ADS)

Paksamut, J.; Boonsong, P.

2018-03-01

In this study, the purpose of our interest is to investigatethe adsorption behavior of copper (II) ions in aqueous solution using some tannin-rich plants as natural bio-adsorbents such as mangosteen peels (Garciniamangostana L.), cassava leaves (Manihotesculenta Crantz) and Thai copper pod leaves (Sennasiamea (Lam.)) as powder form in different dosage of adsorbent plant materials.The adsorption capacities at different pH of solution and contact time were performed.All the experiments in this studywere chosen at room temperature by batch technique. From the experimental results showed that cassava leaves gave better adsorbent properties than mangosteen peels and Thai copper pod leaves. The increasing dosage of all adsorbents and contact time have been found to increase adsorption capacities. In this respect, the adsorption capacities depend crucially on the adsorbents and contact time. The optimum pH of copper (II) ions adsorption was pH4. According to this work, it was observed that bioadsorbent materials from tannin-rich plants could be used to remove copper (II) ions from aqueous solutions.

A Cooperative Copper Metal-Organic Framework-Hydrogel System Improves Wound Healing in Diabetes.

PubMed

Xiao, Jisheng; Chen, Siyu; Yi, Ji; Zhang, Hao; Ameer, Guillermo A

2017-01-05

Chronic non-healing wounds remain a major clinical challenge that would benefit from the development of advanced, regenerative dressings that promote wound closure within a clinically relevant time frame. The use of copper ions has shown promise in wound healing applications possibly by promoting angiogenesis. However, reported treatments that use copper ions require multiple applications of copper salts or oxides to the wound bed, exposing the patient to potentially toxic levels of copper ions and resulting in variable outcomes. Herein we set out to assess whether copper metal organic framework nanoparticles (HKUST-1 NPs) embedded within an antioxidant thermoresponsive citrate-based hydrogel would decrease copper ion toxicity and accelerate wound healing in diabetic mice. HKUST-1 and poly-(polyethyleneglycol citrate-co- N -isopropylacrylamide) (PPCN) were synthesized and characterized. HKUST-1 NP stability in a protein solution with and without embedding them in PPCN hydrogel was determined. Copper ion release, cytotoxicity, apoptosis, and in vitro migration processes were measured. Wound closure rates and wound blood perfusion were assessed in vivo using the splinted excisional dermal wound diabetic mouse model. HKUST-1 NP disintegrated in protein solution while HKUST-1 NPs embedded in PPCN (H-HKUST-1) were protected from degradation and copper ions were slowly released. Cytotoxicity and apoptosis due to copper ion release were significantly reduced while dermal cell migration in vitro and wound closure rates in vivo were significantly enhanced. In vivo , H-HKUST-1 induced angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice. These results suggest that a cooperatively stabilized, copper ion-releasing H-HKUST-1 hydrogel is a promising innovative dressing for the treatment of chronic wounds.

Localization and Specification of Copper Ions in Biofilms on Corroding Copper Surfaces.

DTIC Science & Technology

1994-01-01

WW~nhi~. OC ;mmS 1 . Agency use unay (L-mUv umia. IA. "O" ,.ie. $3. Report Type and Dates Covered. I 1994 Final - Proceedings 4. Title and Subtitle. S...structure (XANES) techniques can be used to differentiate Cu’ 1 and Cu+2 species within biofilms attached to surfaces. Copper ions , uld not be... 1 The organism with associated polymer has been shown to bind copper ions from solution. Geesey et al.2 demonstrated that exopolymers produced by

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

PubMed

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

2013-09-01

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

Multi-biofunctional polymer graphene composite for bone tissue regeneration that elutes copper ions to impart angiogenic, osteogenic and bactericidal properties.

PubMed

Jaidev, L R; Kumar, Sachin; Chatterjee, Kaushik

2017-11-01

Despite several recent advances, poor vascularization in implanted scaffolds impedes complete regeneration for clinical success of bone tissue engineering. The present study aims to develop a multi-biofunctional nanocomposite for bone tissue regeneration using copper nanoparticle decorated reduced graphene oxide (RGO_Cu) hybrid particles in polycaprolactone (PCL) matrix (PCL/RGO_Cu). X-ray photoelectron spectroscopy and X-ray diffraction confirmed the presence of copper oxides (CuO and Cu 2 O) on RGO. Thermogravimetric analysis showed that 11.8% of copper was decorated on RGO. PCL/RGO_Cu exhibited steady release of copper ions in contrast to burst release from the composite containing copper alone (PCL/Cu). PCL/RGO_Cu exhibited highest modulus due to enhanced filler exfoliation. Endothelial cells rapidly proliferated on PCL/RGO_Cu confirming cytocompatibility. The sustained release of ions from PCL/RGO_Cu composites augmented tube formation by endothelial cells evidenced enhanced angiogenic activity. Gene expression of angiogenic markers VEGF and ANG-2 was higher on PCL/RGO_Cu compared to PCL. The osteogenic activity of PCL/RGO_Cu was confirmed by the 87% increase in mineral deposition by pre-osteoblasts compared to PCL. The bactericidal activity of PCL/RGO_Cu showed 78% reduction in viability of Escherichia coli. Thus, the multi-biofunctional PCL/RGO_Cu composite exhibits angiogenic, osteogenic and bactericidal properties, a step towards addressing some of the critical challenges in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Kinetics of copper ion absorption by cross-linked calcium polyacrylate membranes

NASA Technical Reports Server (NTRS)

Philipp, W. H.; May, C. E.

1983-01-01

The absorption of copper ions from aqueous copper acetate solutions by cross-linked calcium acrylate membranes was found to obey parabolic kinetics similar to that found for oxidation of metals that form protective oxide layers. For pure calcium polyacrylate membranes the rate constant was essentially independent of copper acetate concentration and film thickness. For a cross-linked copolymer film of polyvinyl alcohol and calcium polyacrylate, the rate constant was much greater and dependent on the concentration of copper acetate. The proposed mechanism in each case involves the formation of a copper polyacrylate phase on the surface of the membrane. The diffusion of the copper ion through this phase appears to be the rate controlling step for the copolymer film. The diffusion of the calcium ion is apparently the rate controlling step for the calcium polyacrylate. At low pH, the copper polyacrylate phase consists of the normal copper salt; at higher pH, the phase appears to be the basic copper salt.

Comparative Proteomic Analysis of the Molecular Responses of Mouse Macrophages to Titanium Dioxide and Copper Oxide Nanoparticles Unravels Some Toxic Mechanisms for Copper Oxide Nanoparticles in Macrophages

PubMed Central

Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Collin-Faure, Véronique; Chevallet, Mireille; Diemer, Hélène; Gerdil, Adèle; Proamer, Fabienne; Strub, Jean-Marc; Habert, Aurélie; Herlin, Nathalie; Van Dorsselaer, Alain; Carrière, Marie; Rabilloud, Thierry

2015-01-01

Titanium dioxide and copper oxide nanoparticles are more and more widely used because of their catalytic properties, of their light absorbing properties (titanium dioxide) or of their biocidal properties (copper oxide), increasing the risk of adverse health effects. In this frame, the responses of mouse macrophages were studied. Both proteomic and targeted analyses were performed to investigate several parameters, such as phagocytic capacity, cytokine release, copper release, and response at sub toxic doses. Besides titanium dioxide and copper oxide nanoparticles, copper ions were used as controls. We also showed that the overall copper release in the cell does not explain per se the toxicity observed with copper oxide nanoparticles. In addition, both copper ion and copper oxide nanoparticles, but not titanium oxide, induced DNA strands breaks in macrophages. As to functional responses, the phagocytic capacity was not hampered by any of the treatments at non-toxic doses, while copper ion decreased the lipopolysaccharide-induced cytokine and nitric oxide productions. The proteomic analyses highlighted very few changes induced by titanium dioxide nanoparticles, but an induction of heme oxygenase, an increase of glutathione synthesis and a decrease of tetrahydrobiopterin in response to copper oxide nanoparticles. Subsequent targeted analyses demonstrated that the increase in glutathione biosynthesis and the induction of heme oxygenase (e.g. by lovastatin/monacolin K) are critical for macrophages to survive a copper challenge, and that the intermediates of the catecholamine pathway induce a strong cross toxicity with copper oxide nanoparticles and copper ions. PMID:25902355

Active screen cage pulsed dc discharge for implanting copper in polytetrafluoroethylene (PTFE)

NASA Astrophysics Data System (ADS)

Zaka-ul-Islam, Mujahid; Naeem, Muhammad; Shafiq, Muhammad; Sitara; Jabbar Al-Rajab, Abdul; Zakaullah, Muhammad

2017-07-01

Polymers such as polytetrafluoroethylene (PTFE) are widely used in artificial organs where long-term anti-bacterial properties are required to avoid bacterial proliferation. Copper or silver ion implantation on the polymer surface is known as a viable method to generate long-term anti-bacterial properties. Here, we have tested pulsed DC plasma with copper cathodic cage for the PTFE surface treatment. The surface analysis of the treated specimens suggests that the surface, structural properties, crystallinity and chemical structure of the PTFE have been changed, after the plasma treatment. The copper release tests show that copper ions are released from the polymer at a slow rate and quantity of the released copper increases with the plasma treatment time.

Metal lost and found: dissipative uses and releases of copper in the United States 1975-2000.

PubMed

Lifset, Reid J; Eckelman, Matthew J; Harper, E M; Hausfather, Zeke; Urbina, Gonzalo

2012-02-15

Metals are used in a variety of ways, many of which lead to dissipative releases to the environment. Such releases are relevant from both a resource use and an environmental impact perspective. We present a historical analysis of copper dissipative releases in the United States from 1975 to 2000. We situate all dissipative releases in copper's life cycle and introduce a conceptual framework by which copper dissipative releases may be categorized in terms of intentionality of use and release. We interpret our results in the context of larger trends in production and consumption and government policies that have served as drivers of intentional copper releases from the relevant sources. Intentional copper releases are found to be both significant in quantity and highly variable. In 1975, for example, the largest source of intentional releases was from the application of copper-based pesticides, and this decreased more than 50% over the next 25 years; all other sources of intentional releases increased during that period. Overall, intentional copper releases decreased by approximately 15% from 1975 to 2000. Intentional uses that are unintentionally released such as copper from roofing, increased by the same percentage. Trace contaminant sources such as fossil fuel combustion, i.e., sources where both the use and the release are unintended, increased by nearly 50%. Intentional dissipative uses are equivalent to 60% of unintentional copper dissipative releases and more than five times that from trace sources. Dissipative copper releases are revealed to be modest when compared to bulk copper flows in the economy, and we introduce a metric, the dissipation index, which may be considered an economy-wide measure of resource efficiency for a particular substance. We assess the importance of dissipative releases in the calculation of recycling rates, concluding that the inclusion of dissipation in recycling rate calculations has a small, but discernible, influence, and should

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in Caenorhabditis elegans

PubMed Central

Zanon, Tyler; Kappell, Anthony D.; Petrella, Lisa N.; Andersen, Erik C.; Hristova, Krassimira R.

2016-01-01

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits

A study of the effects of phosphates on copper corrosion in drinking water: Copper release, electrochemical, and surface analysis approach

NASA Astrophysics Data System (ADS)

Kang, Young C.

The following work is the study to evaluate the impact of corrosion inhibitors on the copper metal in drinking water and to investigate the corrosion mechanism in the presence and absence of inhibitors. Electrochemical experiments were conducted to understand the effect of specific corrosion inhibitors in synthetic drinking water which was prepared with controlled specific water quality parameters. Water chemistry was studied by Inductively Coupled Plasma--Atomic Emission Spectroscopy (ICP--AES) to investigate the copper leaching rate with time. Surface morphology, crystallinity of corrosion products, copper oxidation status, and surface composition were characterized by various solid surface analysis methods, such as Scanning Electron Microscopy/Energy--Dispersive Spectrometry (SEM/EDS), Grazing-Incidence-angle X-ray Diffraction (GIXRD), X-ray Photoelectron Spectroscopy (XPS), and Time-of-Flight Secondary Ions Mass Spectrometry (ToF-SIMS). The purpose of the first set of experiments was to test various electrochemical techniques for copper corrosion for short term before studying a long term loop system. Surface analysis techniques were carried out to identify and study the corrosion products that form on the fresh copper metal surface when copper coupons were exposed to test solutions for 2 days of experiments time. The second phase of experiments was conducted with a copper pipe loop system in a synthetic tap water over an extended period of time, i.e., 4 months. Copper release and electrochemically measured corrosion activity profiles were monitored carefully with and without corrosion inhibitor, polyphosphate. A correlation between the copper released into the solution and the electrochemically measured corrosion activities was also attempted. To investigate corrosion products on the copper pipe samples, various surface analysis techniques were applied in this study. Especially, static mass spectra acquisition and element distribution mapping were carried out

Experimental study of copper-alkali ion exchange in glass

NASA Astrophysics Data System (ADS)

Gonella, F.; Caccavale, F.; Bogomolova, L. D.; D'Acapito, F.; Quaranta, A.

1998-02-01

Copper-alkali ion exchange was performed by immersing different silicate glasses (soda-lime and BK7) in different molten eutectic salt baths (CuSO4:Na2SO4 and CuSO4:K2SO4). The obtained optical waveguides were characterized by m-lines spectroscopy for the determination of refractive index profiles, and by secondary ion mass spectrometry for the concentration profiles of the ion species involved in the exchange process. The different oxidation states of copper inside the glass structure were studied by electron paramagnetic resonance and x-ray absorption techniques. Interdiffusion copper coefficients were also determined. The Cu-alkali exchange was observed to give rise to local structural rearrangement of the atoms in the glass matrix. The Cu+ ion was found to mainly govern the exchange process, while competition between Cu-Na and K-Na exchanges occurred when a potassium sulfate bath was used. In this case, significant waveguide modal birefringence was observed.

UV spectroscopy determination of aqueous lead and copper ions in water

NASA Astrophysics Data System (ADS)

Tan, C. H.; Moo, Y. C.; Mat Jafri, M. Z.; Lim, H. S.

2014-05-01

Lead (Pb2+) and copper (Cu2+) ions are very common pollutants in water which have dangerous potential causing serious disease and health problems to human. The aim of this paper is to determine lead and copper ions in aqueous solution using direct UV detection without chemical reagent waste. This technique allow the determination of lead and copper ions from range 0.2 mg/L to 10 mg/L using UV wavelength from 205 nm to 225 nm. The method was successfully applied to synthetic sample with high performance.

Immobilization and release of copper species from a microstructured polypyrrole matrix.

PubMed

González, M B; Brugnoni, L I; Flamini, D O; Quinzani, L M; Saidman, S B

2017-01-01

Copper species immobilization in hollow rectangular-sectioned microtubes of polypyrrole (PPy) electrosynthesized on 316L stainless steel was carried out using two different methods. One of them involved the immobilization after the PPy electropolymerization and the other one during the electrosynthesis process. The electrodes modified with copper species were rotated at different speeds in well water under open-circuit potential conditions. The release of copper species from the PPy matrix and the antibacterial activity against Escherichia coli were analyzed. The obtained results demonstrate that the amount of copper species released as well as the bactericidal effects against E. coli increases with rotation speed. The PPy coating modified with copper species after the electropolymerization reaction exhibited the best performance in terms of antibacterial activity and corrosion protection. These electrodes were tested in a lab-scale continuous flow system for well water disinfection.

Removal of copper ions from aqueous solutions by means of micellar-enhanced ultrafiltration

NASA Astrophysics Data System (ADS)

Kowalska, Izabela; Klimonda, Aleksandra

2017-11-01

The aim of the study was to assess the usefulness of micellar-enhanced ultrafiltration (MEUF) for removal of copper ions from water solutions in comparison with classic ultrafiltration process. The tests were conducted in a semi-pilot membrane installation with the use of ultrafiltration module KOCH/ROMICON® at a transmembrane pressure of 0.05 MPa. The effect of concentration of copper ions on ultrafiltration process efficiency was investigated. The second part of the tests concerned the removal of copper ions by MEUF under wide range of anionic surfactant concentration (0.25, 1, and 5 CMC (critical micelle concentration)). Concentration of copper ions in model solutions was equal to 5, 20, and 50 mg Cu/L. Furthermore, the effect of surfactant leakage to the permeate side during filtration was evaluated. Conducted experiments confirmed effectiveness of MEUF in copper ions removal. For the highest copper concentration in the feed (i.e. 50 mg/L), the average concentration of copper ions in the permeate ranged from 1.2-4.7 mg Cu/L depending on surfactant concentration. During filtration experiments, UF module exhibited stable transport properties for model solutions containing copper. For the highest concentration of metal, the decrease of permeate flux did not exceed 11% after 60 minutes of filtration. In the presence of the surfactant, a slight deterioration of transport properties was observed.

Copper vs. Copper at the Relativistic Heavy Ion Collider (2005)

ScienceCinema

Brookhaven Lab - Fulvia Pilat

2017-12-09

To investigate a new form of matter not seen since the Big Bang, scientists are using a new experimental probe: collisions between two beams of copper ions. The use of intermediate size nuclei is expected to result in intermediate energy density - not as

Triplin, a small molecule, reveals copper ion transport in ethylene signaling from ATX1 to RAN1

PubMed Central

Li, Wenbo; Ye, Yajin; Lu, Juan; Yeh, Kuo-Chen; Xiao, Youli; Li, Laigeng; Binder, Brad M.

2017-01-01

Copper ions play an important role in ethylene receptor biogenesis and proper function. The copper transporter RESPONSIVE-TO-ANTAGONIST1 (RAN1) is essential for copper ion transport in Arabidopsis thaliana. However it is still unclear how copper ions are delivered to RAN1 and how copper ions affect ethylene receptors. There is not a specific copper chelator which could be used to explore these questions. Here, by chemical genetics, we identified a novel small molecule, triplin, which could cause a triple response phenotype on dark-grown Arabidopsis seedlings through ethylene signaling pathway. ran1-1 and ran1-2 are hypersensitive to triplin. Adding copper ions in growth medium could partially restore the phenotype on plant caused by triplin. Mass spectrometry analysis showed that triplin could bind copper ion. Compared to the known chelators, triplin acts more specifically to copper ion and it suppresses the toxic effects of excess copper ions on plant root growth. We further showed that mutants of ANTIOXIDANT PROTEIN1 (ATX1) are hypersensitive to tiplin, but with less sensitivity comparing with the ones of ran1-1 and ran1-2. Our study provided genetic evidence for the first time that, copper ions necessary for ethylene receptor biogenesis and signaling are transported from ATX1 to RAN1. Considering that triplin could chelate copper ions in Arabidopsis, and copper ions are essential for plant and animal, we believe that, triplin not only could be useful for studying copper ion transport of plants, but also could be useful for copper metabolism study in animal and human. PMID:28388654

Triplin, a small molecule, reveals copper ion transport in ethylene signaling from ATX1 to RAN1.

PubMed

Li, Wenbo; Lacey, Randy F; Ye, Yajin; Lu, Juan; Yeh, Kuo-Chen; Xiao, Youli; Li, Laigeng; Wen, Chi-Kuang; Binder, Brad M; Zhao, Yang

2017-04-01

Copper ions play an important role in ethylene receptor biogenesis and proper function. The copper transporter RESPONSIVE-TO-ANTAGONIST1 (RAN1) is essential for copper ion transport in Arabidopsis thaliana. However it is still unclear how copper ions are delivered to RAN1 and how copper ions affect ethylene receptors. There is not a specific copper chelator which could be used to explore these questions. Here, by chemical genetics, we identified a novel small molecule, triplin, which could cause a triple response phenotype on dark-grown Arabidopsis seedlings through ethylene signaling pathway. ran1-1 and ran1-2 are hypersensitive to triplin. Adding copper ions in growth medium could partially restore the phenotype on plant caused by triplin. Mass spectrometry analysis showed that triplin could bind copper ion. Compared to the known chelators, triplin acts more specifically to copper ion and it suppresses the toxic effects of excess copper ions on plant root growth. We further showed that mutants of ANTIOXIDANT PROTEIN1 (ATX1) are hypersensitive to tiplin, but with less sensitivity comparing with the ones of ran1-1 and ran1-2. Our study provided genetic evidence for the first time that, copper ions necessary for ethylene receptor biogenesis and signaling are transported from ATX1 to RAN1. Considering that triplin could chelate copper ions in Arabidopsis, and copper ions are essential for plant and animal, we believe that, triplin not only could be useful for studying copper ion transport of plants, but also could be useful for copper metabolism study in animal and human.

A novel copper/polydimethiylsiloxane nanocomposite for copper-containing intrauterine contraceptive devices.

PubMed

Xu, X X; Ding, M H; Zhang, J X; Zheng, W; Li, L; Zheng, Y F

2013-11-01

In this article, a novel composite of copper (Cu) nanoparticles and polydimethiylsiloxane (PDMS) has been prepared and investigated for the potential application in Cu-containing intrauterine device. The Cu/PDMS composite with various mass fraction of Cu nanoparticles was fabricated via the hot vulcanizing process. The chemical structures and surface morphologies of the Cu/PDMS composites were characterized confirming the physical interaction between Cu nanoparticles and PDMS. The surface morphology observation using scanning electron microscope and atomic force microscope showed the agglomeration of Cu nanoparticles in PDMS matrix and the distribution of the agglomerations was more uniform with increased amount of Cu nanoparticles. The cupric ion release behaviors of the Cu/PDMS composites with different amounts of Cu nanoparticles were investigated in simulated uterine fluid at 37°C for 150 days. The corrosion morphologies of the Cu/PDMS composites were also characterized. Both the burst release rate of the cupric ion in the first few days and the steady release rate after 30-day immersion were improved. The cytotoxicity test has been done for the Cu/PDMS composites. Copyright © 2013 Wiley Periodicals, Inc.

Preparation, characterization and antibacterial properties against E. coli K88 of chitosan nanoparticle loaded copper ions

NASA Astrophysics Data System (ADS)

Du, Wen-Li; Xu, Ying-Lei; Xu, Zi-Rong; Fan, Cheng-Li

2008-02-01

The present study was conducted to prepare and characterize chitosan nanoparticle loaded copper ions, and evaluate their antibacterial activity. Chitosan nanoparticles were prepared based on ionotropic gelation, and then the copper ions were loaded. The particle size, zeta potential and morphology were determined. Antibacterial activity was evaluated against E. coli K88 by determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in vitro. Results showed that the antibacterial activity was significantly enhanced by the loading of copper ions compared to those of chitosan nanoparticles and copper ions. The MIC and MBC of chitosan nanoparticle loaded copper ions were 21 times and 42 times lower than those of copper ions, respectively. To confirm the antibacterial mechanism, morphological changes of E. coli K88 treated by chitosan nanoparticle loaded copper ions were dynamically observed with an atomic force microscope (AFM). It was found that chitosan nanoparticle loaded copper ions killed E. coli K88 through damage to the cell membrane.

Effects of copper ions on the characteristics of egg white gel induced by strong alkali.

PubMed

Shao, Yaoyao; Zhao, Yan; Xu, Mingsheng; Chen, Zhangyi; Wang, Shuzhen; Tu, Yonggang

2017-09-01

This study investigated the effects of copper ions on egg white (EW) gel induced by strong alkali. Changes in gel characteristics were examined through texture profile analysis, scanning electron microscopy (SEM), and chemical methods. The value of gel strength reached its maximum when 0.1% copper ions was added. However, the lowest cohesiveness values were observed at 0.1%. The springiness of gel without copper ions was significantly greater than the gel with copper ions added. SEM results illustrated that the low concentration of copper ions contributes to a dense and uniform gel network, and an open matrix was formed at 0.4%. The free and total sulphhydryl group content in the egg white protein gel significantly decreased with the increased copper. The increase of copper ions left the contents of ionic and hydrogen bonds basically unchanged, hydrophobic interaction presented an increasing trend, and the disulfide bond exhibited a completely opposite change. The change of surface hydrophobicity proved that the main binding force of copper induced gel was hydrophobic interaction. However, copper ions had no effect on the protein component of the gels. Generally, a low level of copper ions facilitates protein-protein association, which is involved in the characteristics of gels. Instead, high ionic strength had a negative effect on gels induced by strong alkali. © 2017 Poultry Science Association Inc.

Role of copper oxides in contact killing of bacteria.

PubMed

Hans, Michael; Erbe, Andreas; Mathews, Salima; Chen, Ying; Solioz, Marc; Mücklich, Frank

2013-12-31

The potential of metallic copper as an intrinsically antibacterial material is gaining increasing attention in the face of growing antibiotics resistance of bacteria. However, the mechanism of the so-called "contact killing" of bacteria by copper surfaces is poorly understood and requires further investigation. In particular, the influences of bacteria-metal interaction, media composition, and copper surface chemistry on contact killing are not fully understood. In this study, copper oxide formation on copper during standard antimicrobial testing was measured in situ by spectroscopic ellipsometry. In parallel, contact killing under these conditions was assessed with bacteria in phosphate buffered saline (PBS) or Tris-Cl. For comparison, defined Cu2O and CuO layers were thermally generated and characterized by grazing incidence X-ray diffraction. The antibacterial properties of these copper oxides were tested under the conditions used above. Finally, copper ion release was recorded for both buffer systems by inductively coupled plasma atomic absorption spectroscopy, and exposed copper samples were analyzed for topographical surface alterations. It was found that there was a fairly even growth of CuO under wet plating conditions, reaching 4-10 nm in 300 min, but no measurable Cu2O was formed during this time. CuO was found to significantly inhibit contact killing, compared to pure copper. In contrast, thermally generated Cu2O was essentially as effective in contact killing as pure copper. Copper ion release from the different surfaces roughly correlated with their antibacterial efficacy and was highest for pure copper, followed by Cu2O and CuO. Tris-Cl induced a 10-50-fold faster copper ion release compared to PBS. Since the Cu2O that primarily forms on copper under ambient conditions is as active in contact killing as pure copper, antimicrobial objects will retain their antimicrobial properties even after oxide formation.

Biosorption of copper ions from dilute aqueous solutions on base treated rubber (Hevea brasiliensis) leaves powder: kinetics, isotherm, and biosorption mechanisms.

PubMed

Wan Ngah, W S; Hanafiah, M A K M

2008-01-01

The efficiency of sodium hydroxide treated rubber (Hevea brasiliensis) leaves powder (NHBL) for removing copper ions from aqueous solutions has been investigated. The effects of physicochemical parameters on biosorption capacities such as stirring speed, pH, biosorbent dose, initial concentrations of copper, and ionic strength were studied. The biosorption capacities of NHBL increased with increase in pH, stirring speed and copper concentration but decreased with increase in biosorbent dose and ionic strength. The isotherm study indicated that NHBL fitted well with Langmuir model compared to Freundlich and Dubinin-Radushkevich models. The maximum biosorption capacity determined from Langmuir isotherm was 14.97 mg/g at 27 degrees C. The kinetic study revealed that pseudosecond order model fitted well the kinetic data, while Boyd kinetic model indicated that film diffusion was the main rate determining step in biosorption process. Based on surface area analysis, NHBL has low surface area and categorized as macroporous. Fourier transform infrared (FT-IR) analyses revealed that hydroxyl, carboxyl, and amino are the main functional groups involved in the binding of copper ions. Complexation was one of the main mechanisms for the removal of copper ions as indicated by FT-IR spectra. Ion exchange was another possible mechanism since the ratio of adsorbed cations (Cu2+ and H+) to the released cations (Na+, Ca2+, and Mg2+) from NHBL was almost unity. Copper ions bound on NHBL were able to be desorbed at > 99% using 0.05 mol/L HCl, 0.01 mol/L HNO3, and 0.01 mol/L EDTA solutions.

Kinetics and Mechanisms of Chemical and Biological Agents Release from Biopolymeric Microcapsules.

PubMed

Vinceković, Marko; Jurić, Slaven; Đermić, Edyta; Topolovec-Pintarić, Snježana

2017-11-08

Kinetics and mechanisms of copper cations and Trichoderma viride spores release from uncoated and chitosan coated alginate microcapsules were investigated. The gelation of a fixed amount of sodium alginate at different concentrations of copper ion solutions resulted in distinct kinetics and release mechanisms. The increase in copper cation concentration promoted, but the presence of the chitosan layer on the microcapsule surface and the increase in microcapsule size reduced the rate of active agent release. Fitting to simple Korsmeyer-Peppas empirical model revealed that the underlying release mechanism (Fickian diffusion or a combination of the diffusion and erosion mechanisms) depends on the copper cation concentration and presence of T. viride spores. The investigation pointed out that the proper selection of formulation variables helps in designing microcapsules with the desirable release of copper ions and T. viride for plant protection and nutrition.

Characterization of Lactobacillus brevis L62 strain, highly tolerant to copper ions.

PubMed

Mrvčić, Jasna; Butorac, Ana; Solić, Ema; Stanzer, Damir; Bačun-Družina, Višnja; Cindrić, Mario; Stehlik-Tomas, Vesna

2013-01-01

Lactic acid bacteria (LAB) as starter culture in food industry must be suitable for large-scale industrial production and possess the ability to survive in unfavorable processes and storage conditions. Approaches taken to address these problems include the selection of stress-resistant strains. In food industry, LAB are often exposed to metal ions induced stress. The interactions between LAB and metal ions are very poorly investigated. Because of that, the influence of non-toxic, toxic and antioxidant metal ions (Zn, Cu, and Mn) on growth, acid production, metal ions binding capacity of wild and adapted species of Leuconostoc mesenteroides L3, Lactobacillus brevis L62 and Lactobacillus plantarum L73 were investigated. The proteomic approach was applied to clarify how the LAB cells, especially the adapted ones, protect themselves and tolerate high concentrations of toxic metal ions. Results have shown that Zn and Mn addition into MRS medium in the investigated concentrations did not have effect on the bacterial growth and acid production, while copper ions were highly toxic, especially in static conditions. Leuc. mesenteroides L3 was the most efficient in Zn binding processes among the chosen LAB species, while L. plantarum L73 accumulated the highest concentration of Mn. L. brevis L62 was the most copper resistant species. Adaptation had a positive effect on growth and acid production of all species in the presence of copper. However, the adapted species incorporated less metal ions than the wild species. The exception was adapted L. brevis L62 that accumulated high concentration of copper ions in static conditions. The obtained results showed that L. brevis L62 is highly tolerant to copper ions, which allows its use as starter culture in fermentative processes in media with high concentration of copper ions.

Determining the Amount of Copper(II) Ions in a Solution Using a Smartphone

ERIC Educational Resources Information Center

Montangero, Marc

2015-01-01

When dissolving copper in nitric acid, copper(II) ions produce a blue-colored solution. It is possible to determine the concentration of copper(II) ions, focusing on the hue of the color, using a smartphone camera. A free app can be used to measure the hue of the solution, and with the help of standard copper(II) solutions, one can graph a…

Measurement of electron-ion relaxation in warm dense copper

DOE PAGES

Cho, B. I.; Ogitsu, T.; Engelhorn, K.; ...

2016-01-06

Experimental investigation of electron-ion coupling and electron heat capacity of copper in warm and dense states are presented. From time-resolved x-ray absorption spectroscopy, the temporal evolution of electron temperature is obtained for non-equilibrium warm dense copper heated by an intense femtosecond laser pulse. Electron heat capacity and electron-ion coupling are inferred from the initial electron temperature and its decrease over 10 ps. As a result, data are compared with various theoretical models.

Effects of Excess Copper Ions on Decidualization of Human Endometrial Stromal Cells.

PubMed

Li, Ying; Kang, Zhen-Long; Qiao, Na; Hu, Lian-Mei; Ma, Yong-Jiang; Liang, Xiao-Huan; Liu, Ji-Long; Yang, Zeng-Ming

2017-05-01

The aim of this study was to investigate the effects of copper ions on decidualization of human endometrial stromal cells (HESCs) cultured in vitro. Firstly, non-toxic concentrations of copper D-gluconate were screened in HESCs based on cell activity. Then, the effects of non-toxic concentrations of copper ions (0~250 μM) were examined on decidualization of human endometrial stromal cells. Our data demonstrated that the mRNA expressions of insulin-like growth factor binding protein (IGFBP-1), prolactin (PRL), Mn-SOD, and FOXO1were down-regulated during decidualization following the treatments with 100 or 250 μM copper ions. Meanwhile, the amount of malonaldehyde (MDA) in the supernatant of HESCs was increased. These results showed that in vitro decidualization of HESCs was impaired by copper treatment.

Form and toxicity of copper released into aquatic systems from conventionally and nano-sized copper treated lumber

EPA Science Inventory

The fate and effects of pristine engineered nanomaterials (ENMs) in simplified systems have been widely studied; however, little is known about the potential release and impact of metal ENMs from consumer goods, such as lumber treated with micronized copper. Micronized copper tre...

Assessing the Release of Copper from Nanocopper-treated and Conventional Copper-treated Lumber into Marine Waters II: Forms and Bioavailability

EPA Science Inventory

One application of nanocopper is as a wood‐preserving pesticide in pressure‐treated lumber. Recent research has shown that pressure‐treated lumber amended with micronized copper azole (MCA), which contains nanosized copper, releases copper under estuarine and ma...

Assessing the Release of Copper from Nanocopper-treated and Conventional Copper-treated Lumber into Marine Waters I: Concentrations and Rates

EPA Science Inventory

Little is known about the release of metal engineered nanomaterials (ENMs) from consumer goods, including lumber treated with micronized copper. Micronized copper is a recent form of antifouling wood preservative containing nanosized copper particles for use in pressure‐tre...

Tuning silver ion release properties in reactively sputtered Ag/TiOx nanocomposites

NASA Astrophysics Data System (ADS)

Xiong, J.; Ghori, M. Z.; Henkel, B.; Strunskus, T.; Schürmann, U.; Deng, M.; Kienle, L.; Faupel, F.

2017-07-01

Silver/titania nanocomposites with strong bactericidal effects and good biocompatibility/environmental safety show a high potential for antibacterial applications. Tailoring the silver ion release is thus highly promising to optimize the antibacterial properties of such coatings and to preserve biocompatibility. Reactive sputtering is a fast and versatile method for the preparation of such Ag/TiOx nanocomposites coatings. The present work is concerned with the influence of sputter parameters on the surface morphology and silver ion release properties of reactively sputtered Ag/TiOx nanocomposites coatings showing a silver nanoparticle size distribution in the range from 1 to 20 nm. It is shown that the silver ion release rate strongly depends on the total pressure: the coatings prepared at lower pressure present a lower but long-lasting release behavior. The much denser structure produced under these conditions reduces the transport of water molecules into the coating. In addition, the influence of microstructure and thickness of titanium oxide barriers on the silver ion release were investigated intensively. Moreover, for the coatings prepared at high total pressure, it was demonstrated that stable and long-lasting silver release can be achieved by depositing a barrier with a high rate. Nanocomposites produced under these conditions show well controllable silver ion release properties for applications as antibacterial coatings.

Form and toxicity of copper released into marine systems from ...

EPA Pesticide Factsheets

The fate and effects of pristine engineered nanomaterials (ENMs) in simplified systems have been widely studied; however, little is known about the potential release and impact of ENMs from consumer goods, especially lumber that has been treated with micronized copper. Micronized copper solutions contain copper complexes predominately in the 10-700 nm size range, and are used in lumber to prevent microbial degradation and fouling. In this work, the goal was to determine the rate, concentration, and form of copper released from commercially available pressure treated lumber samples (blocks and sawdust) exposed to an aqueous system. Lumber tested included Southern Yellow Pine (SYP) treated with micronized copper azole (MCA) at 0.96 and 2.4 Kg/m3, alkaline copper quaternary (ACQ) at 0.30 and 9.6 Kg/m3, and chromated copper arsenate (CCA) at 40 Kg/m3. Of the different chemical treatments, only MCA included nano- and micro-sized copper complexes. The experimental system included wood cubes cut from the outer 2 cm surface of the lumber or the equivalent mass (4 g) of sawdust submerged in 250 mL of media (0, 1, 10, and 30 ppt filtered natural seawater) in polyethylene bottles, and mixed on a shaker table at 120 rpm. Water samples were taken at 8 hours, and on days 1, 2, 7, 14, and 28 for the blocks and days 1, 2, 3, 7, 17, and 28 for the sawdust. Subsamples included unfiltered water (defined as 0.45 µm - filtered water for the sawdust), and water filtered through a 0.

Copper Metallochaperones

PubMed Central

Robinson, Nigel J.; Winge, Dennis R.

2014-01-01

The current state of knowledge on how copper metallochaperones support the maturation of cuproproteins is reviewed. Copper is needed within mitochondria to supply the CuA and intramembrane CuB sites of cytochrome oxidase, within the trans-Golgi network to supply secreted cuproproteins and within the cytosol to supply superoxide dismutase 1 (Sod1). Subpopulations of copper-zinc superoxide dismutase also localize to mitochondria, the secretory system, the nucleus and, in plants, the chloroplast, which also requires copper for plastocyanin. Prokaryotic cuproproteins are found in the cell membrane and in the periplasm of gram-negative bacteria. Cu(I) and Cu(II) form tight complexes with organic molecules and drive redox chemistry, which unrestrained would be destructive. Copper metallochaperones assist copper in reaching vital destinations without inflicting damage or becoming trapped in adventitious binding sites. Copper ions are specifically released from copper metallochaperones upon contact with their cognate cuproproteins and metal transfer is thought to proceed by ligand substitution. PMID:20205585

Rechargeable calcium phosphate orthodontic cement with sustained ion release and re-release

NASA Astrophysics Data System (ADS)

Zhang, Ling; Weir, Michael D.; Chow, Laurence C.; Reynolds, Mark A.; Xu, Hockin H. K.

2016-11-01

White spot lesions (WSL) due to enamel demineralization are major complications for orthodontic treatments. Calcium phosphate (CaP) dental resins with Ca and P ion releases are promising for remineralization. However, previous Ca and P releases lasted for only weeks. Experimental orthodontic cements were developed using pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA) at mass ratio of 1:1 (PE); and PE plus 10% of 2-hydroxyethyl methacrylate (HEMA) and 5% of bisphenol A glycidyl dimethacrylate (BisGMA) (PEHB). Particles of amorphous calcium phosphate (ACP) were incorporated into PE and PEHB at 40% filler level. Specimens were tested for bracket-enamel shear bond strength, water sorption, CaP release, and ion recharge and re-release. PEHB+40ACP had higher bracket-enamel bond strength and ion release and rechargeability than PE+40ACP. ACP incorporation into the novel orthodontic cement did not adversely affect the bracket-enamel bond strength. Ion release and re-release from the novel ACP orthodontic cement indicated favorable release and re-release patterns. The recharged orthodontic cement could release CaP ions continuously for four weeks without further recharge. Novel rechargeable orthodontic cement containing ACP was developed with a high bracket-enamel bond strength and the ability to be repeatedly recharged to maintain long-term high levels of CaP ion releases.

Rechargeable calcium phosphate orthodontic cement with sustained ion release and re-release

PubMed Central

Zhang, Ling; Weir, Michael D.; Chow, Laurence C.; Reynolds, Mark A.; Xu, Hockin H. K.

2016-01-01

White spot lesions (WSL) due to enamel demineralization are major complications for orthodontic treatments. Calcium phosphate (CaP) dental resins with Ca and P ion releases are promising for remineralization. However, previous Ca and P releases lasted for only weeks. Experimental orthodontic cements were developed using pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA) at mass ratio of 1:1 (PE); and PE plus 10% of 2-hydroxyethyl methacrylate (HEMA) and 5% of bisphenol A glycidyl dimethacrylate (BisGMA) (PEHB). Particles of amorphous calcium phosphate (ACP) were incorporated into PE and PEHB at 40% filler level. Specimens were tested for bracket-enamel shear bond strength, water sorption, CaP release, and ion recharge and re-release. PEHB+40ACP had higher bracket-enamel bond strength and ion release and rechargeability than PE+40ACP. ACP incorporation into the novel orthodontic cement did not adversely affect the bracket-enamel bond strength. Ion release and re-release from the novel ACP orthodontic cement indicated favorable release and re-release patterns. The recharged orthodontic cement could release CaP ions continuously for four weeks without further recharge. Novel rechargeable orthodontic cement containing ACP was developed with a high bracket-enamel bond strength and the ability to be repeatedly recharged to maintain long-term high levels of CaP ion releases. PMID:27808251

Neurokinin B and serum albumin limit copper binding to mammalian gonadotropin releasing hormone.

PubMed

Gul, Ahmad Samir; Tran, Kevin K; Jones, Christopher E

2018-02-26

Gonadotropin releasing hormone (GnRH) triggers secretion of luteinizing hormone and follicle stimulating hormone from gonadotropic cells in the anterior pituitary gland. GnRH is able to bind copper, and both in vitro and in vivo studies have suggested that the copper-GnRH complex is more potent at triggering gonadotropin release than GnRH alone. However, it remains unclear whether copper-GnRH is the active species in vivo. To explore this we have estimated the GnRH-copper affinity and have examined whether GnRH remains copper-bound in the presence of serum albumin and the neuropeptide neurokinin B, both copper-binding proteins that GnRH will encounter in vivo. We show that GnRH has a copper dissociation constant of ∼0.9 × 10 -9  M, however serum albumin and neurokinin B can extract metal from the copper-GnRH complex. It is therefore unlikely that a copper-GnRH complex will survive transit through the pituitary portal circulation and that any effect of copper must occur outside the bloodstream in the absence of neurokinin B. Copyright © 2018 Elsevier Inc. All rights reserved.

Synergistic cytotoxic effects of ions released by zinc-aluminum bronze and the metallic salts on osteoblastic cells.

PubMed

Grillo, Claudia A; Morales, María L; Mirífico, María V; Fernández Lorenzo de Mele, Mónica A

2013-07-01

The use of copper-based alloys for fixed dental crowns and bridges is increasingly widespread in several countries. The aim of this work is to study the dissolution of a zinc-aluminum-bronze and the cytotoxic effects of the ions released on UMR-106 osteoblastic cell line. Two sources of ions were used: (1) ions released by the metal alloy immersed in the cell culture and (2) salts of the metal ions. Conventional electrochemical techniques, atomic absorption spectroscopy [to obtain the average concentration of ions (AC) in solution], and energy dispersive X-ray (EDX) spectroscopy analysis were used to study the corrosion process. Corrosion tests revealed a strong influence of the composition of the electrolyte medium and the immersion time on the electrochemical response. The cytotoxicity was evaluated with (a) individual ions, (b) combinations of two ions, and (c) the mixture of all the ions released by a metal disc of the alloy. Importantly, synergistic cytotoxic effects were found when Al-Zn ion combinations were used at concentration levels lower than the cytotoxic threshold values of the individual ions. Cytotoxic effects in cells in the vicinity of the metal disc were also found. These results were interpreted considering synergistic effects and a diffusion controlled mechanism that yields to concentration levels, in the metal surroundings, several times higher than the measured AC value. Copyright © 2013 Wiley Periodicals, Inc.

Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions.

PubMed

Chang, Yi Kuo; Chang, Juu En; Chiang, Li Choung

2003-08-01

Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS). Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex.

Separation of copper ions from iron ions using PVA-g-(acrylic acid/N-vinyl imidazole) membranes prepared by radiation-induced grafting.

PubMed

Ajji, Zaki; Ali, Ali M

2010-01-15

Acrylic acid (AAc), N-vinyl imidazole (Azol) and their binary mixtures were graft copolymerized onto poly(vinyl alcohol) membranes using gamma irradiation. The ability of the grafted membranes to separate Cu ions from Fe ions was investigated with respect to the grafting yield and the pH of the feed solution. The data showed that the diffusion of copper ions from the feed compartment to the receiver compartment depends on the grafting yield of the membranes and the pH of the feed solution. To the contrary, iron ions did not diffuse through the membranes of all grafting yields. However, a limited amount of iron ions diffused in strong acidic medium. This study shows that the prepared membranes could be considered for the separation of copper ions from iron ions. The temperature of thermal decomposition of pure PVA-g-AAc/Azol membrane, PVA-g-AAc/Azol membrane containing copper ions, and PVA-g-AAc/Azol membrane containing iron ions were determined using TGA analyzer. It was shown that the presence of Cu and Fe ions increases the decomposition temperature, and the membranes bonded with iron ions are more stable than those containing copper ions.

Examining mechanism of toxicity of copper oxide nanoparticles to Saccharomyces cerevisiae and Caenorhabditis elegans

NASA Astrophysics Data System (ADS)

Mashock, Michael J.

Copper oxide nanoparticles (CuO NPs) are an up and coming technology increasingly being used in industrial and consumer applications and thus may pose risk to humans and the environment. In the present study, the toxic effects of CuO NPs were studied with two model organisms Saccharomyces cerevisiae and Caenorhabditis elegans. The role of released Cu ions during dissolution of CuO NPs in growth media were studied with freshly suspended, aged NPs, and the released Cu 2+ fraction. Exposures to the different Cu treatments showed significant inhibition of S. cerevisiae cellular metabolic activity. Inhibition from the NPs was inversely proportional to size and was not fully explained by the released Cu ions. S. cerevisiae cultures grown under respiring conditions demonstrated greater metabolic sensitivity when exposed to CuO NPs compared to cultures undergoing fermentation. The cellular response to both CuO NPs and released Cu ions on gene expression was analyzed via microarray analysis after an acute exposure. It was observed that both copper exposures resulted in an increase in carbohydrate storage, a decrease in protein production, protein misfolding, increased membrane permeability, and cell cycle arrest. Cells exposed to NPs up-regulated genes related to oxidative phosphorylation but also may be inducing cell cycle arrest by a different mechanism than that observed with released Cu ions. The effect of CuO NPs on C. elegans was examined by using several toxicological endpoints. The CuO NPs displayed a more inhibitory effect, compared to copper sulfate, on nematode reproduction, feeding, and development. We investigated the effects of copper oxide nanoparticles and copper sulfate on neuronal health, a known tissue vulnerable to heavy metal toxicity. In transgenic C. eleganswith neurons expressing a green fluorescent protein reporter, neuronal degeneration was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, nematode

Incorporation of copper ions into crystals of T2 copper-depleted laccase from Botrytis aclada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osipov, E. M., E-mail: e.m.osipov@gmail.com; Polyakov, K. M.; Engelhardt Institute of Molecular Biology, Vavilova str. 32, Moscow 119991

2015-11-18

The restoration of the native form of laccase from B. aclada from the type 2 copper-depleted form of the enzyme was investigated. Copper ions were found to be incorporated into the active site after soaking the depleted enzyme in a Cu{sup +}-containing solution. Laccases belong to the class of multicopper oxidases catalyzing the oxidation of phenols accompanied by the reduction of molecular oxygen to water without the formation of hydrogen peroxide. The activity of laccases depends on the number of Cu atoms per enzyme molecule. The structure of type 2 copper-depleted laccase from Botrytis aclada has been solved previously. Withmore » the aim of obtaining the structure of the native form of the enzyme, crystals of the depleted laccase were soaked in Cu{sup +}- and Cu{sup 2+}-containing solutions. Copper ions were found to be incorporated into the active site only when Cu{sup +} was used. A comparative analysis of the native and depleted forms of the enzymes was performed.« less

Magnetic separation of heavy metal ions and evaluation based on surface-enhanced Raman spectroscopy: copper(II) ions as a case study.

PubMed

Yan, Xue; Zhang, Xue-Jiao; Yuan, Ya-Xian; Han, San-Yang; Xu, Min-Min; Gu, Ren'ao; Yao, Jian-Lin

2013-11-01

A new approach was developed for the magnetic separation of copper(II) ions with easy operation and high efficiency. p-Mercaptobenzoic acid served as the modified tag of Fe2O3@Au nanoparticles both for the chelation ligand and Raman reporter. Through the chelation between the copper(II) ions and carboxyl groups on the gold shell, the Fe2O3@Au nanoparticles aggregated to form networks that were enriched and separated from the solution by a magnet. A significant decrease in the concentration of copper(II) ions in the supernatant solution was observed. An extremely sensitive method based on surface-enhanced Raman spectroscopy was employed to detect free copper(II) ions that remained after the magnetic separation, and thus to evaluate the separation efficiency. The results indicated the intensities of the surface-enhanced Raman spectroscopy bands from p-mercaptobenzoic acid were dependent on the concentration of copper(II) ions, and the concentration was decreased by several orders of magnitude after the magnetic separation. The present protocol effectively decreased the total amount of heavy metal ions in the solution. This approach opens a potential application in the magnetic separation and highly sensitive detection of heavy metal ions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluoride release and recharge behavior of a nano-filled resin-modified glass ionomer compared with that of other fluoride releasing materials.

PubMed

Mitra, Sumita B; Oxman, Joe D; Falsafi, Afshin; Ton, Tiffany T

2011-12-01

To compare the long-term fluoride release kinetics of a novel nano-filled two-paste resin-modified glass-ionomer (RMGI), Ketac Nano (KN) with that of two powder-liquid resin-modified glass-ionomers, Fuji II LC (FLC) and Vitremer (VT) and one conventional glass-ionomer, Fuji IX (FIX). Fluoride release was measured in vitro using ion-selective electrodes. Kinetic analysis was done using regression analysis and compared with existing models for GIs and compomers. In a separate experiment the samples of KN and two conventional glass-ionomers, FIX and Ketac Molar (KM) were subjected to a treatment with external fluoride source (Oral-B Neutra-Foam) after 3 months of fluoride release and the recharge behavior studied for an additional 7-day period. The cumulative amount of fluoride released from KN, VT and FLC and the release profiles were statistically similar but greater than that for FIX at P < 0.05. All four materials, including KN, showed a burst of fluoride ions at shorter times (t) and an overall rate dependence on t1/2 typical for glass-ionomers. The coating of KN with its primer and of DY with its adhesive did not significantly alter the fluoride release behavior of the respective materials. The overall rate for KN was significantly higher than for the compomer DY. DY showed a linear rate of release vs. t and no burst effect as expected for compomers. The nanoionomer KN showed fluoride recharge behavior similar to the conventional glass ionomers FIX and KM. Thus, it was concluded that the new RMGI KN exhibits fluoride ion release behavior similar to typical conventional and RMGIs and that the primer does not impede the release of fluoride.

The Lumenal Loop Met672–Pro707 of Copper-transporting ATPase ATP7A Binds Metals and Facilitates Copper Release from the Intramembrane Sites*

PubMed Central

Barry, Amanda N.; Otoikhian, Adenike; Bhatt, Sujata; Shinde, Ujwal; Tsivkovskii, Ruslan; Blackburn, Ninian J.; Lutsenko, Svetlana

2011-01-01

The copper-transporting ATPase ATP7A has an essential role in human physiology. ATP7A transfers the copper cofactor to metalloenzymes within the secretory pathway; inactivation of ATP7A results in an untreatable neurodegenerative disorder, Menkes disease. Presently, the mechanism of ATP7A-mediated copper release into the secretory pathway is not understood. We demonstrate that the characteristic His/Met-rich segment Met672–Pro707 (HM-loop) that connects the first two transmembrane segments of ATP7A is important for copper release. Mutations within this loop do not prevent the ability of ATP7A to form a phosphorylated intermediate during ATP hydrolysis but inhibit subsequent dephosphorylation, a step associated with copper release. The HM-loop inserted into a scaffold protein forms two structurally distinct binding sites and coordinates copper in a mixed His-Met environment with an ∼2:1 stoichiometry. Binding of either copper or silver, a Cu(I) analog, induces structural changes in the loop. Mutations of 4 Met residues to Ile or two His-His pairs to Ala-Gly decrease affinity for copper. Altogether, the data suggest a two-step process, where copper released from the transport sites binds to the first His(Met)2 site, triggering a structural change and binding to a second 2-coordinate His-His or His-Met site. We also show that copper binding within the HM-loop stabilizes Cu(I) and protects it from oxidation, which may further aid the transfer of copper from ATP7A to acceptor proteins. The mechanism of copper entry into the secretory pathway is discussed. PMID:21646353

Visual Observation of Dissolution of Copper Ions from a Copper Electrode

ERIC Educational Resources Information Center

Ikemoto, Isao; Saitou, Kouichi

2013-01-01

During electrolysis, to visually observe the conversion of a metal to its cation, either the cation or its complex ion should have a distinct color while the electrolyte solution must be colorless and transparent. A demonstration is described in which copper is used as the electrodes and sodium polyacrylate (a superabsorbent polymer) solution is…

Plasma immersion ion implantation for reducing metal ion release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz, C.; Garcia, J. A.; Maendl, S.

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.more » 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.« less

Copper amplification of prostaglandin E/sub 2/ stimulation of the release of luteinizing hormone-releasing hormone is a postreceptor event

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnea, A.; Cho, G.

1987-01-01

The authors have shown that copper amplifies prostaglandin E/sub 2/ (PGE/sub 2/) stimulation of luteinizing hormone-releasing hormone (LH-RH) from explants of the median eminence area (MEA) and that this process is calcium-dependent. Since a Ca-cAMP pathway has been implicated in PGE/sub 2/ action on the LH-RH neuron, in this study the authors wished to ascertain if copper exerts its effect on the PGE/sub 2/ receptor or on a postreceptor component involved in PGE/sub 2/ action. MEA of adult male rats were incubated for 5 min with 200 ..mu..M Cu/histidine and then incubated for 15 min either with 10 ..mu..M PGE/submore » 2/ (Cu/PGE/sub 2/), 100 ..mu..M forskolin (Cu/forskolin), or 1 mM 8-bromoadenosine 3',5'-cyclic monophosphate (Cu/cAMP). Basal release of LH-RH was 4.6 +/- 0.45 pg/15 min per MEA determined by radioimmunoassay. Net stimulated release during the 15-min exposure to PGE/sub 2/, forskolin, or 8-bromoadenosine 3',5'-cyclic monophosphate was 3.6 +/- 0.52, 3.1 +/- 0.39, and 1.6 +/- 0.42 pg/15 min per MEA, respectively. Net stimulated release after exposure to Cu/PGE/sub 2/, Cu/forskolin, or Cu/cAMP indicated that copper amplifies the action of PGE/sub 2/ and forskolin but not cAMP action. When MEA were exposed to a mixture of PGE/sub 2/ and forskolin for 15 min, the effects of these two secretagogues on LH-RH release were not additive. In contrast to PGE/sub 2/ and forskolin, copper did not amplify K/sup +/ stimulation of OH-RH release. These results are supportive of the proposition that PGE/sub 2/ stimulation of OH-RH release is mediated by the Ca-cAMP pathway and that copper amplification of PGE/sub 2/ action is a postreceptor event.« less

Monitoring copper release in drinking water distribution systems.

PubMed

d'Antonio, L; Fabbricino, M; Panico, A

2008-01-01

A new procedure, recently proposed for on-line monitoring of copper released from metal pipes in household plumbing system for drinking water distribution during the development of corrosion processes, is tested experimentally. Experiments were carried out in laboratory controlled conditions, using synthetic water and varying the water alkalinity. The possibility of using the corrosion potential as a surrogate measure of copper concentration in stagnating water is shown, verifying, in the meantime, the effect of alkalinity on the development of passivation phenomena, which tend to protect the pipe from corrosion processes. Experimental data are discussed, highlighting the potentiality of the procedure, and recognizing its limitations. Copyright IWA Publishing 2008.

Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

NASA Astrophysics Data System (ADS)

Wang, Hui; Yang, Hongshuai; Liu, Jiahui; Li, Yanhong; Liu, Zhigang

2015-07-01

A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18-34°C) and copper ion concentration (0.1-1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant ( P<0.01), the quadratic effects of temperature were significant ( P<0.05), the linear effects of copper ion concentration were not significant ( P>0.05), and the quadratic effects of copper ion concentration were significant ( P<0.05). Additionally, the synergistic effects of temperature and copper ion concentration were not significant ( P>0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

Copper ion as a new leakage tracer.

PubMed

Modaresi, J; Baharizade, M; Shareghi, A; Ahmadi, M; Daneshkazemi, A

2013-12-01

Most failures of root canal treatments are caused by bacteria. Studies showed that the most common cause of endodontic failures were the incomplete obturation of the root canal and the lack of adequate apical seal. Some in-vitro methods are used to estimate sealing quality, generally by measuring microleakage that allows the tracer agent to penetrate the filled canal. Conventional methods of evaluating the seal of endodontically treated teeth are complicated and have some drawbacks. We used copper ion diffusion method to assess the leakage and the results were compared to dye penetration method. The crowns of 21 extracted teeth were cut off at the CEJ level. After preparing the canals, the teeth were placed in tubes containing saline. They were divided randomly into 15 experimental cases; 3 positive and 3 negative controls. Positive controls were filled by single cone without sealer while the experimental and the negative control groups were filled by lateral technique. The coronal portion of gutta was removed and 9mm was left. The external surface of each tooth was coated with nail polish. Two millimeters of apical portion was immersed into 9ml of distilled water and 0.3ml of CuSO4 solution was injected into the coronal portion. After 2 days, copper sulfate was measured by an atomic absorption spectrophotometer. The teeth were then immersed in 2% methylene blue for 24 hours, sectioned and the extent of dye penetration was measured by a stereomicroscope. The maximum and minimum recorded copper ion concentrations for the experimental group were 18.37 and 2.87ppm respectively. The maximum and minimum recorded dye penetrations for the experimental group were 8.5 and 3.5mm respectively. The statistical analysis, adopting paired samples test, showed poor correlation between average recorded results of two methods. Based on our results, there was no significant correlation between the dye penetration and the copper ion diffusion methods.

Cell density dependence of Microcystis aeruginosa responses to copper algaecide concentrations: Implications for microcystin-LR release.

PubMed

Kinley, Ciera M; Iwinski, Kyla J; Hendrikse, Maas; Geer, Tyler D; Rodgers, John H

2017-11-01

Along with mechanistic models, predictions of exposure-response relationships for copper are often derived from laboratory toxicity experiments with standardized experimental exposures and conditions. For predictions of copper toxicity to algae, cell density is a critical factor often overlooked. For pulse exposures of copper-based algaecides in aquatic systems, cell density can significantly influence copper sorbed by the algal population, and consequent responses. A cyanobacterium, Microcystis aeruginosa, was exposed to a copper-based algaecide over a range of cell densities to model the density-dependence of exposures, and effects on microcystin-LR (MC-LR) release. Copper exposure concentrations were arrayed to result in a gradient of MC-LR release, and masses of copper sorbed to algal populations were measured following exposures. While copper exposure concentrations eliciting comparable MC-LR release ranged an order of magnitude (24-h EC50s 0.03-0.3mg Cu/L) among cell densities of 10 6 through 10 7 cells/mL, copper doses (mg Cu/mg algae) were similar (24-h EC50s 0.005-0.006mg Cu/mg algae). Comparisons of MC-LR release as a function of copper exposure concentrations and doses provided a metric of the density dependence of algal responses in the context of copper-based algaecide applications. Combined with estimates of other site-specific factors (e.g. water characteristics) and fate processes (e.g. dilution and dispersion, sorption to organic matter and sediments), measuring exposure-response relationships for specific cell densities can refine predictions for in situ exposures and algal responses. These measurements can in turn decrease the likelihood of amending unnecessary copper concentrations to aquatic systems, and minimize risks for non-target aquatic organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties

NASA Astrophysics Data System (ADS)

Kim, Young-Hwan; Choi, Yu-ri; Kim, Kwang-Mahn; Choi, Se-Young

2012-02-01

Antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori of copper ion was researched. Also, additional effects of copper ion coating on optical and mechanical properties were researched as well. Copper ion was coated on glass substrate as a thin film to prevent bacteria from growing. Cupric nitrate was used as precursors for copper ion. The copper ion contained sol was deposited by spin coating process on glass substrate. Then, the deposited substrates were heat treated at the temperature range between 200 °C and 250 °C. The thickness of deposited copper layer on the surface was 63 nm. The antibacterial effect of copper ion coated glass on P. aeruginosa, S. typhimurium and H. pylori demonstrated excellent effect compared with parent glass. Copper ion contained layer on glass showed a similar value of transmittance compared with value of parent glass. The 3-point bending strength and Vickers hardness were 209.2 MPa, 540.9 kg/mm2 which were about 1.5% and 1.3% higher than the value of parent glass. From these findings, it is clear that copper ion coating on glass substrate showed outstanding effect not only in antibacterial activity but also in optical and mechanical properties as well.

Colorimetric assay of copper ions based on the inhibition of peroxidase-like activity of MoS2 nanosheets

NASA Astrophysics Data System (ADS)

Chen, Huan; Li, Zhihong; Liu, Xueting; Zhong, Jianhai; Lin, Tianran; Guo, Liangqia; Fu, Fengfu

2017-10-01

The peroxidase-like catalytic activity of MoS2 nanomaterials has been utilized for colorimetric bioassays and medical diagnostics. However, the application of peroxidase-like catalytic activity of MoS2 nanomaterials in environmental analysis was seldom explored. Herein, copper ions were found to inhibit the peroxidase-like catalytic activity of MoS2 nanosheets, which can catalyze the oxidation of 3, 3‧, 5, 5‧-tetramethylbenzidine by H2O2 to produce a colorimetric product. Based on this finding, a simple sensitive colorimetric method for the detection of copper ions was developed. In the presence of copper ions, the absorbance and color of the solution decreased with the increasing concentration of copper ions. The color of the solution can be used to semi-quantitative on-site assay of copper ions by naked eyes. A linear relationship between the absorbance and the concentration of copper ions was observed in the range of 0.4-4.0 μmol L- 1 with a detection limit of 92 nmol L- 1, which was much lower than the maximum contaminant level of copper in drinking water legislated by the Environmental Protection Agency of USA and the World Health Organization. The method was applied to detect copper ions in environmental water samples with satisfactory results.

Stabilization of the Thermal Decomposition of Poly(Propylene Carbonate) Through Copper Ion Incorporation and Use in Self-Patterning

NASA Astrophysics Data System (ADS)

Spencer, Todd J.; Chen, Yu-Chun; Saha, Rajarshi; Kohl, Paul A.

2011-06-01

Incorporation of copper ions into poly(propylene carbonate) (PPC) films cast from γ-butyrolactone (GBL), trichloroethylene (TCE) or methylene chloride (MeCl) solutions containing a photo-acid generator is shown to stabilize the PPC from thermal decomposition. Copper ions were introduced into the PPC mixtures by bringing the polymer mixture into contact with copper metal. The metal was oxidized and dissolved into the PPC mixture. The dissolved copper interferes with the decomposition mechanism of PPC, raising its decomposition temperature. Thermogravimetric analysis shows that copper ions make PPC more stable by up to 50°C. Spectroscopic analysis indicates that copper ions may stabilize terminal carboxylic acid groups, inhibiting PPC decomposition. The change in thermal stability based on PPC exposure to patterned copper substrates was used to provide a self-aligned patterning method for PPC on copper traces without the need for an additional photopatterning registration step. Thermal decomposition of PPC is then used to create air isolation regions around the copper traces. The spatial resolution of the self-patterning PPC process is limited by the lateral diffusion of the copper ions within the PPC. The concentration profiles of copper within the PPC, patterning resolution, and temperature effects on the PPC decomposition have been studied.

Precise method to determine points on isentropic release curve on copper

NASA Astrophysics Data System (ADS)

Remiot, C.; Mexmain, J. M.; Bonnet, L.

1996-05-01

When a higher shock impedance foil (with several hundreds of μm in thickness) is set on the studied material surface, the release phase occurs by steps, whose duration of each plateau corresponds to a go and return of the shock wave in the foil. Step velocity levels can be easily measured by D.L.I. technique. The intermediate velocity values, connected with the knowledge of the foil Hugoniot, allow us to determine a few points on the isentropic release curve. The experiments have been achieved on a two stage light gas gun with a projectile velocity varying from 1400 to 3000 m/s. The caliber of the launcher is 30 mm. For this study concerning copper, the target is composed of a 2 mm thickness copper transmitter on which the sample is mechanically held. The tungsten (W) thick foil is, under pressure, sticked on the sample with UV stick-cord. The free surface velocity measurement accuracy of the tungsten foil is 0.4% for values between 1500 to 3500 m/s. The first shock in the sample is varying from 40 to 120 GPa and the mass velocity from 800 to 2000 m/s. By impedance matching between the copper sample and the tungsten thick foil, we deduce for each experiment three points on the copper isentropic release curve and the final free surface velocity. The accuracy we obtain is in order of 0.4 GPa for the pressure and 10 m/s for the mass velocity.

Antimicrobial and bone-forming activity of a copper coated implant in a rabbit model.

PubMed

Prinz, Cornelia; Elhensheri, Mohamed; Rychly, Joachim; Neumann, Hans-Georg

2017-08-01

Current strategies in implant technology are directed to generate bioactive implants that are capable to activate the regenerative potential of the surrounding tissue. On the other hand, implant-related infections are a common problem in orthopaedic trauma patients. To meet both challenges, i.e. to generate a bone implant with regenerative and antimicrobial characteristics, we tested the use of copper coated nails for surgical fixation in a rabbit model. Copper acetate was galvanically deposited with a copper load of 1 µg/mm 2 onto a porous oxide layer of Ti6Al4V nails, which were used for the fixation of a tibia fracture, inoculated with bacteria. After implantation of the nail the concentration of copper ions did not increase in blood which indicates that copper released from the implant was locally restricted to the fracture site. After four weeks, analyses of the extracted implants revealed a distinct antimicrobial effect of copper, because copper completely prevented both a weak adhesion and firm attachment of biofilm-forming bacteria on the titanium implant. To evaluate fracture healing, radiographic examination demonstrated an increased callus index in animals with copper coated nails. This result indicates a stimulated bone formation by releasing copper ions. We conclude that the use of implants with a defined load of copper ions enables both prevention of bacterial infection and the stimulation of regenerative processes.

Removal of copper ions from aqueous solutions by a steel-making by-product.

PubMed

López, F A; Martín, M I; Pérez, C; López-Delgado, A; Alguacil, F J

2003-09-01

A study is made of the use of a steel-making by-product (rolling mill scale) as a material for removing Cu(2+) ions from aqueous solutions. The influence of contact time, initial copper ion concentration and temperature on removal capability is considered. The removal of Cu(2+) ions from an aqueous solution involves two processes: on the one hand, the adsorption of Cu(2+) ions on the surface of mill scale due to the iron oxides present in the latter; and on the other hand, the cementation of Cu(2+) onto metallic iron contained in the mill scale. Rolling mill scale is seen to be an effective material for the removal of copper ions from aqueous solutions.

Effects of blending of desalinated water with treated surface drinking water on copper and lead release.

PubMed

Liu, Haizhou; Schonberger, Kenneth D; Korshin, Gregory V; Ferguson, John F; Meyerhofer, Paul; Desormeaux, Erik; Luckenbach, Heidi

2010-07-01

This study examined effects of desalinated water on the corrosion of and metal release from copper and lead-containing materials. A jar test protocol was employed to examine metal release from copper and lead-tin coupons exposed to water chemistries with varying blending ratios of desalinated water, alkalinities, pHs and orthophosphate levels. Increasing fractions of desalinated water in the blends resulted in non-monotonic changes of copper and lead release, with generally lower metal concentrations in the presence of desalinated water, especially when its contribution increased from 80% to 100%. SEM examination showed that the increased fractions of desalinated water were associated with pronounced changes of the morphology of the corrosion scales, likely due to the influence of natural organic matter. This hypothesis was corroborated by the existence of correlations between changes of the zeta-potential of representative minerals (malachite and hydrocerussite) and metal release. For practical applications, maintaining pH at 7.8 and adding 1 mg/L orthophosphate as PO(4) were concluded to be adequate to decrease copper and lead release. Lower alkalinity of desalinated water was beneficial for blends containing 50% or more desalinated water. Copyright 2010 Elsevier Ltd. All rights reserved.

Surface Modification of NiTi Alloy via Cathodic Plasma Electrolytic Deposition and its Effect on Ni Ion Release and Osteoblast Behaviors

NASA Astrophysics Data System (ADS)

Yan, Ying; Cai, Kaiyong; Yang, Weihu; Liu, Peng

2013-07-01

To reduce Ni ion release and improve biocompatibility of NiTi alloy, the cathodic plasma electrolytic deposition (CPED) technique was used to fabricate ceramic coating onto a NiTi alloy surface. The formation of a coating with a rough and micro-textured surface was confirmed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, respectively. An inductively coupled plasma mass spectrometry test showed that the formed coating significantly reduced the release of Ni ions from the NiTi alloy in simulated body fluid. The influence of CPED treated NiTi substrates on the biological behaviors of osteoblasts, including cell adhesion, cell viability, and osteogenic differentiation function (alkaline phosphatase), was investigated in vitro. Immunofluorescence staining of nuclei revealed that the CPED treated NiTi alloy was favorable for cell growth. Osteoblasts on CPED modified NiTi alloy showed greater cell viability than those for the native NiTi substrate after 4 and 7 days cultures. More importantly, osteoblasts cultured onto a modified NiTi sample displayed significantly higher differentiation levels of alkaline phosphatase. The results suggested that surface functionalization of NiTi alloy with ceramic coating via the CPED technique was beneficial for cell proliferation and differentiation. The approach presented here is useful for NiTi implants to enhance bone osseointegration and reduce Ni ion release in vitro.

Copper Metal-Organic Framework Nanoparticles Stabilized with Folic Acid Improve Wound Healing in Diabetes.

PubMed

Xiao, Jisheng; Zhu, Yunxiao; Huddleston, Samantha; Li, Peng; Xiao, Baixue; Farha, Omar K; Ameer, Guillermo A

2018-02-27

The successful treatment of chronic nonhealing wounds requires strategies that promote angiogenesis, collagen deposition, and re-epithelialization of the wound. Copper ions have been reported to stimulate angiogenesis; however, several applications of copper salts or oxides to the wound bed are required, leading to variable outcomes and raising toxicity concerns. We hypothesized that copper-based metal-organic framework nanoparticles (Cu-MOF NPs), referred to as HKUST-1, which are rapidly degraded in protein solutions, can be modified to slowly release Cu 2+ , resulting in reduced toxicity and improved wound healing rates. Folic acid was added during HKUST-1 synthesis to generate folic-acid-modified HKUST-1 (F-HKUST-1). The effect of folic acid incorporation on NP stability, size, hydrophobicity, surface area, and copper ion release profile was measured. In addition, cytotoxicity and in vitro cell migration processes due to F-HKUST-1 and HKUST-1 were evaluated. Wound closure rates were assessed using the splinted excisional dermal wound model in diabetic mice. The incorporation of folic acid into HKUST-1 enabled the slow release of copper ions, which reduced cytotoxicity and enhanced cell migration in vitro. In vivo, F-HKUST-1 induced angiogenesis, promoted collagen deposition and re-epithelialization, and increased wound closure rates. These results demonstrate that folic acid incorporation into HKUST-1 NPs is a simple, safe, and promising approach to control Cu 2+ release, thus enabling the direct application of Cu-MOF NPs to wounds.

Metal ions in macrophage antimicrobial pathways: emerging roles for zinc and copper

PubMed Central

Stafford, Sian L.; Bokil, Nilesh J.; Achard, Maud E. S.; Kapetanovic, Ronan; Schembri, Mark A.; McEwan, Alastair G.; Sweet, Matthew J.

2013-01-01

The immunomodulatory and antimicrobial properties of zinc and copper have long been appreciated. In addition, these metal ions are also essential for microbial growth and survival. This presents opportunities for the host to either harness their antimicrobial properties or limit their availability as defence strategies. Recent studies have shed some light on mechanisms by which copper and zinc regulation contribute to host defence, but there remain many unanswered questions at the cellular and molecular levels. Here we review the roles of these two metal ions in providing protection against infectious diseases in vivo, and in regulating innate immune responses. In particular, we focus on studies implicating zinc and copper in macrophage antimicrobial pathways, as well as the specific host genes encoding zinc transporters (SLC30A, SLC39A family members) and CTRs (copper transporters, ATP7 family members) that may contribute to pathogen control by these cells. PMID:23738776

Reagent precipitation of copper ions from wastewater of machine-building factories

NASA Astrophysics Data System (ADS)

Porozhnyuk, L. A.; Lupandina, N. S.; Porozhnyuk, E. V.

2018-03-01

The article presents the results of reagent removal of copper ions from wastewater of machine-building factories. The urgency of the study is conditioned by the widening of the range of effective reagents through the implementation of industrial waste. The investigation covers mineralogical and fractional composition of chalk enrichment waste. In the work, the conditions of thermal activation of chalk enrichment waste used for reagent removal of copper ions from wastewater were elaborated. It was shown that the thermal activation of waste facilitates the increased treatment efficacy up to the set sanitation, hygiene and technological standards.

Copper Reduction and Contact Killing of Bacteria by Iron Surfaces

PubMed Central

Mathews, Salima; Kumar, Ranjeet

2015-01-01

The well-established killing of bacteria by copper surfaces, also called contact killing, is currently believed to be a combined effect of bacterial contact with the copper surface and the dissolution of copper, resulting in lethal bacterial damage. Iron can similarly be released in ionic form from iron surfaces and would thus be expected to also exhibit contact killing, although essentially no contact killing is observed by iron surfaces. However, we show here that the exposure of bacteria to iron surfaces in the presence of copper ions results in efficient contact killing. The process involves reduction of Cu2+ to Cu+ by iron; Cu+ has been shown to be considerably more toxic to cells than Cu2+. The specific Cu+ chelator, bicinchoninic acid, suppresses contact killing by chelating the Cu+ ions. These findings underline the importance of Cu+ ions in the contact killing process and infer that iron-based alloys containing copper could provide novel antimicrobial materials. PMID:26150470

Secondary electron emission characteristics of ion-textured copper and high-purity isotropic graphite surfaces

NASA Technical Reports Server (NTRS)

Curren, A. N.; Jensen, K. A.

1984-01-01

Experimentally determined values of true secondary electron emission and relative values of reflected primary electron yield for untreated and ion textured oxygen free high conductivity copper and untreated and ion textured high purity isotropic graphite surfaces are presented for a range of primary electron beam energies and beam impingement angles. This investigation was conducted to provide information that would improve the efficiency of multistage depressed collectors (MDC's) for microwave amplifier traveling wave tubes in space communications and aircraft applications. For high efficiency, MDC electrode surfaces must have low secondary electron emission characteristics. Although copper is a commonly used material for MDC electrodes, it exhibits relatively high levels of secondary electron emission if its surface is not treated for emission control. Recent studies demonstrated that high purity isotropic graphite is a promising material for MDC electrodes, particularly with ion textured surfaces. The materials were tested at primary electron beam energies of 200 to 2000 eV and at direct (0 deg) to near grazing (85 deg) beam impingement angles. True secondary electron emission and relative reflected primary electron yield characteristics of the ion textured surfaces were compared with each other and with those of untreated surfaces of the same materials. Both the untreated and ion textured graphite surfaces and the ion treated copper surface exhibited sharply reduced secondary electron emission characteristics relative to those of untreated copper. The ion treated graphite surface yielded the lowest emission levels.

Form and toxicity of copper released into marine systems from conventionally and nano-sized copper treated lumber

EPA Science Inventory

The fate and effects of pristine engineered nanomaterials (ENMs) in simplified systems have been widely studied; however, little is known about the potential release and impact of ENMs from consumer goods, especially lumber that has been treated with micronized copper. Micronized...

Characteristics and antimicrobial activity of copper-based materials

NASA Astrophysics Data System (ADS)

Li, Bowen

In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger

Copper ion sensing with fluorescent electrospun nanofibers.

PubMed

Ongun, Merve Zeyrek; Ertekin, Kadriye; Gocmenturk, Mustafa; Ergun, Yavuz; Suslu, Aslıhan

2012-05-01

In this work, the use of electrospun nanofibrous materials as highly responsive fluorescence quenching-based copper sensitive chemosensor is reported. Poly(methyl methacrylate) and ethyl cellulose were used as polymeric support materials. Sensing slides were fabricated by electrospinning technique. Copper sensors based on the change in the fluorescence signal intensity of fluoroionophore; N'-3-(4-(dimethylamino phenly)allylidene)isonicotinohydrazide. The sensor slides exhibited high sensitivities due to the high surface area of the nanofibrous membrane structures. The preliminary results of Stern-Volmer analysis show that the sensitivities of electrospun nanofibrous membranes to detect Cu(II) ions are 6-20-fold higher than those of the continuous thin films. By this way we obtained linear calibration plots for Cu(II) ions in the concentration range of 10(-12)-10(-5)M. The response times of the sensing slides were less than 1 min. Stability of the employed ionophore in the matrix materials was excellent and when stored in the ambient air of the laboratory there was no significant drift in signal intensity after 6 months. Our stability tests are still in progress. Copyright © 2012 Elsevier B.V. All rights reserved.

Rapid assessment of human amylin aggregation and its inhibition by copper(II) ions by laser ablation electrospray ionization mass spectrometry with ion mobility separation

DOE PAGES

Li, Hang; Ha, Emmeline; Donaldson, Robert P.; ...

2015-09-09

Native electrospray ionization (ESI) mass spectrometry (MS) is often used to monitor noncovalent complex formation between peptides and ligands. The relatively low throughput of this technique, however, is not compatible with extensive screening. Laser ablation electrospray ionization (LAESI) MS combined with ion mobility separation (IMS) can analyze complex formation and provide conformation information within a matter of seconds. Islet amyloid polypeptide (IAPP) or amylin, a 37-amino acid residue peptide, is produced in pancreatic beta-cells through proteolytic cleavage of its prohormone. Both amylin and its precursor can aggregate and produce toxic oligomers and fibrils leading to cell death in the pancreasmore » that can eventually contribute to the development of type 2 diabetes mellitus. The inhibitory effect of the copper(II) ion on amylin aggregation has been recently discovered, but details of the interaction remain unknown. Finding other more physiologically tolerated approaches requires large scale screening of potential inhibitors. In this paper, we demonstrate that LAESI-IMS-MS can reveal the binding stoichiometry, copper oxidation state, and the dissociation constant of human amylin–copper(II) complex. The conformations of hIAPP in the presence of copper(II) ions were also analyzed by IMS, and preferential association between the β-hairpin amylin monomer and the metal ion was found. The copper(II) ion exhibited strong association with the —HSSNN– residues of the amylin. In the absence of copper(II), amylin dimers were detected with collision cross sections consistent with monomers of β-hairpin conformation. When copper(II) was present in the solution, no dimers were detected. Thus, the copper(II) ions disrupt the association pathway to the formation of β-sheet rich amylin fibrils. Using LAESI-IMS-MS for the assessment of amylin–copper(II) interactions demonstrates the utility of this technique for the high-throughput screening of

Copper Complexation Screen Reveals Compounds with Potent Antibiotic Properties against Methicillin-Resistant Staphylococcus aureus

PubMed Central

Haeili, Mehri; Moore, Casey; Davis, Christopher J. C.; Cochran, James B.; Shah, Santosh; Shrestha, Tej B.; Zhang, Yaofang; Bossmann, Stefan H.; Benjamin, William H.

2014-01-01

Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface. PMID:24752262

Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash.

PubMed

Tahmasbi, Soodeh; Ghorbani, Mohammad; Masudrad, Mahdis

2015-01-01

Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022" Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0.016", round) were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0.05). Corrosion rate of brackets coupled with NiTi wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them.

Galvanic Corrosion of and Ion Release from Various Orthodontic Brackets and Wires in a Fluoride-containing Mouthwash

PubMed Central

Tahmasbi, Soodeh; Ghorbani, Mohammad; Masudrad, Mahdis

2015-01-01

Background and aims. This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. Materials and methods. This study was conducted on 24 lower central incisor 0.022" Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0.016", round) were immersed in Oral-B mouthwash containing 0.05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte weremeasured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. Results. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0.05). Corrosion rate of brackets coupled with NiTi wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. Conclusion. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them. PMID:26697148

Copper ions removal from water using functionalized carbon nanotubes–mullite composite as adsorbent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tofighy, Maryam Ahmadzadeh; Mohammadi, Toraj, E-mail: torajmohammadi@iust.ac.ir

Highlights: • CNTs–mullite composite was prepared via chemical vapor deposition (CVD) method. • The prepared composite was modified with concentrated nitric acid and chitosan. • The modified CNTs–mullite composites were used as novel adsorbents. • Copper ion removal from water by the prepared adsorbents was performed. • Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. - Abstract: Carbon nanotubes–mullite composite was synthesized by direct growth of carbon nanotubes on mullite particles via chemical vapor deposition method using cyclohexanol and ferrocene as carbon precursor and catalyst, respectively. The carbon nanotubes–mullite composite was oxidized withmore » concentrated nitric acid and functionalized with chitosan and then used as a novel adsorbent for copper ions removal from water. The results demonstrated that modification with concentrated nitric acid and chitosan improves copper ions adsorption capacity of the prepared composite, significantly. Langmuir and Freundlich isotherms and two kinetic models were applied to fit the experimental data. The carbon nanotubes growth on mullite particles to form the carbon nanotubes–mullite composite with further modification is an inherently safe approach for many promising environmental applications to avoid some concerns regarding environment, health and safety. It was found that the modified carbon nanotubes–mullite composite can be considered as an excellent adsorbent for copper ions removal from water.« less

Antibacterial Behavior of Additively Manufactured Porous Titanium with Nanotubular Surfaces Releasing Silver Ions.

PubMed

Amin Yavari, S; Loozen, L; Paganelli, F L; Bakhshandeh, S; Lietaert, K; Groot, J A; Fluit, A C; Boel, C H E; Alblas, J; Vogely, H C; Weinans, H; Zadpoor, A A

2016-07-13

Additive manufacturing (3D printing) has enabled fabrication of geometrically complex and fully interconnected porous biomaterials with huge surface areas that could be used for biofunctionalization to achieve multifunctional biomaterials. Covering the huge surface area of such porous titanium with nanotubes has been already shown to result in improved bone regeneration performance and implant fixation. In this study, we loaded TiO2 nanotubes with silver antimicrobial agents to equip them with an additional biofunctionality, i.e., antimicrobial behavior. An optimized anodizing protocol was used to create nanotubes on the entire surface area of direct metal printed porous titanium scaffolds. The nanotubes were then loaded by soaking them in three different concentrations (i.e., 0.02, 0.1, and 0.5 M) of AgNO3 solution. The antimicrobial behavior and cell viability of the developed biomaterials were assessed. As far as the early time points (i.e., up to 1 day) are concerned, the biomaterials were found to be extremely effective in preventing biofilm formation and decreasing the number of planktonic bacteria particularly for the middle and high concentrations of silver ions. Interestingly, nanotubes not loaded with antimicrobial agents also showed significantly smaller numbers of adherent bacteria at day 1, which may be attributed to the bactericidal effect of high aspect ratio nanotopographies. The specimens with the highest concentrations of antimicrobial agents adversely affected cell viability at day 1, but this effect is expected to decrease or disappear in the following days as the rate of release of silver ions was observed to markedly decrease within the next few days. The antimicrobial effects of the biomaterials, particularly the ones with the middle and high concentrations of antimicrobial agents, continued until 2 weeks. The potency of the developed biomaterials in decreasing the number of planktonic bacteria and hindering the formation of biofilms make

The importance of extracellular speciation and corrosion of copper nanoparticles on lung cell membrane integrity.

PubMed

Hedberg, Jonas; Karlsson, Hanna L; Hedberg, Yolanda; Blomberg, Eva; Odnevall Wallinder, Inger

2016-05-01

Copper nanoparticles (Cu NPs) are increasingly used in various biologically relevant applications and products, e.g., due to their antimicrobial and catalytic properties. This inevitably demands for an improved understanding on their interactions and potential toxic effects on humans. The aim of this study was to investigate the corrosion of copper nanoparticles in various biological media and to elucidate the speciation of released copper in solution. Furthermore, reactive oxygen species (ROS) generation and lung cell (A549 type II) membrane damage induced by Cu NPs in the various media were studied. The used biological media of different complexity are of relevance for nanotoxicological studies: Dulbecco's modified eagle medium (DMEM), DMEM(+) (includes fetal bovine serum), phosphate buffered saline (PBS), and PBS+histidine. The results show that both copper release and corrosion are enhanced in DMEM(+), DMEM, and PBS+histidine compared with PBS alone. Speciation results show that essentially no free copper ions are present in the released fraction of Cu NPs in neither DMEM(+), DMEM nor histidine, while labile Cu complexes form in PBS. The Cu NPs were substantially more membrane reactive in PBS compared to the other media and the NPs caused larger effects compared to the same mass of Cu ions. Similarly, the Cu NPs caused much more ROS generation compared to the released fraction only. Taken together, the results suggest that membrane damage and ROS formation are stronger induced by Cu NPs and by free or labile Cu ions/complexes compared with Cu bound to biomolecules. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

THE ROLE OF PIPE AGEING IN COPPER CORROSION BY-PRODUCT RELEASE

EPA Science Inventory

The presence of sulphate, bicarbonate and orthophosphate can change the type of solid present in systems containing cupric ion or cupric hydroxide solids. In some cases, a short-term reduction in copper solubility is realized, but over longer periods of time formation of basic c...

Copper complexation screen reveals compounds with potent antibiotic properties against methicillin-resistant Staphylococcus aureus.

PubMed

Haeili, Mehri; Moore, Casey; Davis, Christopher J C; Cochran, James B; Shah, Santosh; Shrestha, Tej B; Zhang, Yaofang; Bossmann, Stefan H; Benjamin, William H; Kutsch, Olaf; Wolschendorf, Frank

2014-07-01

Macrophages take advantage of the antibacterial properties of copper ions in the killing of bacterial intruders. However, despite the importance of copper for innate immune functions, coordinated efforts to exploit copper ions for therapeutic interventions against bacterial infections are not yet in place. Here we report a novel high-throughput screening platform specifically developed for the discovery and characterization of compounds with copper-dependent antibacterial properties toward methicillin-resistant Staphylococcus aureus (MRSA). We detail how one of the identified compounds, glyoxal-bis(N4-methylthiosemicarbazone) (GTSM), exerts its potent strictly copper-dependent antibacterial properties on MRSA. Our data indicate that the activity of the GTSM-copper complex goes beyond the general antibacterial effects of accumulated copper ions and suggest that, in contrast to prevailing opinion, copper complexes can indeed exhibit species- and target-specific activities. Based on experimental evidence, we propose that copper ions impose structural changes upon binding to the otherwise inactive GTSM ligand and transfer antibacterial properties to the chelate. In turn, GTSM determines target specificity and utilizes a redox-sensitive release mechanism through which copper ions are deployed at or in close proximity to a putative target. According to our proof-of-concept screen, copper activation is not a rare event and even extends to already established drugs. Thus, copper-activated compounds could define a novel class of anti-MRSA agents that amplify copper-dependent innate immune functions of the host. To this end, we provide a blueprint for a high-throughput drug screening campaign which considers the antibacterial properties of copper ions at the host-pathogen interface. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Impact on sediments and water by release of copper from chalcopyrite bearing rock due to acidic mine drainage

NASA Astrophysics Data System (ADS)

Shukla, Anoop Kant; Pradhan, Manoj; Tiwari, Onkar Nath

2018-04-01

Mining activity causes transition of rock-mass from its original position in earth into open environment. The action of environmental elements such air, water, microorganisms leads to oxidation of minerals which constitute the rock. The oxidation of sulphide minerals in presence of moisture releases acidic mine discharge (AMD). The acidic nature of AMD causes leaching of metals from rock minerals. Dissolution of other minerals may occur upon reaction with AMD. Chalcopyrite (CuFeS2) undergoes oxidation in acidic condition releasing copper among other products. This study reveals contamination of copper in sediment samples and seepage water from the tailing dam of a large copper project in located in central India. Elevation was studied using GIS to ascertain to the topographic elevation of tailing dam area. It was located at relatively high altitude causing seepage to flow away from tailing dam. The seepage water from tailing dam was found to be acidic with mean pH value of 4.0 and elevated copper content. Similarly, sediments from seepage water flow displayed elevated copper concentration. The copper concentration in seepage water was found with a mean value of 10.73 mg/l. The sediments from seepage water flow also displayed elevated copper concentration with mean value of 26.92 g/kg. This indicates impact on sediments by release of copper due to acidic mine drainage.

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences.

PubMed

Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

2014-01-01

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug-fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug-fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid.

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences

PubMed Central

Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

2014-01-01

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. PMID:25114504

Laser cladding of stainless steel with a copper-silver alloy to generate surfaces of high antimicrobial activity

NASA Astrophysics Data System (ADS)

Hans, Michael; Támara, Juan Carlos; Mathews, Salima; Bax, Benjamin; Hegetschweiler, Andreas; Kautenburger, Ralf; Solioz, Marc; Mücklich, Frank

2014-11-01

Copper and silver are used as antimicrobial agents in the healthcare sector in an effort to curb infections caused by bacteria resistant to multiple antibiotics. While the bactericidal potential of copper and silver alone are well documented, not much is known about the antimicrobial properties of copper-silver alloys. This study focuses on the antibacterial activity and material aspects of a copper-silver model alloy with 10 wt% Ag. The alloy was generated as a coating with controlled intermixing of copper and silver on stainless steel by a laser cladding process. The microstructure of the clad was found to be two-phased and in thermal equilibrium with minor Cu2O inclusions. Ion release and killing of Escherichia coli under wet conditions were assessed with the alloy, pure silver, pure copper and stainless steel. It was found that the copper-silver alloy, compared to the pure elements, exhibited enhanced killing of E. coli, which correlated with an up to 28-fold increased release of copper ions. The results show that laser cladding with copper and silver allows the generation of surfaces with enhanced antimicrobial properties. The process is particularly attractive since it can be applied to existing surfaces.

Solid state solubility of copper oxides in hydroxyapatite

NASA Astrophysics Data System (ADS)

Zykin, Mikhail A.; Vasiliev, Alexander V.; Trusov, Lev A.; Dinnebier, Robert E.; Jansen, Martin; Kazin, Pavel E.

2018-06-01

Samples containing copper oxide doped hydroxyapatite with the composition Ca10(PO4)6(CuxOH1-x-δ)2, x = 0.054 - 0.582, in the mixture with CuO/Cu2O were prepared by a solid-state high-temperature treatment at varying annealing temperatures and at different partial water vapor and oxygen pressures. The crystal structures of the apatite compounds were refined using powder X-ray diffraction patterns and the content of copper ions x in the apatite was determined. Copper ions enter exclusively into the apatite trigonal channels formally substituting protons of OH-groups and the hexagonal cell parameters grow approximately linearly with x, the channel volume mostly expanding while the remaining volume of the crystal lattice changing only slightly. The equilibrium copper content in the apatite increases drastically, by almost a factor of 10 with the annealing temperature rising from 800° to 1200°C. The reduction of the water partial pressure leads to a further increase of x, while the dependence of x on the oxygen partial pressure exhibits a maximum. The observed relations are consistent with the proposed chemical reactions implying the copper introduction is followed by the release of a considerable quantity of gaseous products - water and oxygen. The analysis of interatomic distances suggests that the maximum content of copper ions in the channel cannot exceed 2/3.

Insufficiency of copper ion homeostasis causes freeze-thaw injury of yeast cells as revealed by indirect gene expression analysis.

PubMed

Takahashi, Shunsuke; Ando, Akira; Takagi, Hiroshi; Shima, Jun

2009-11-01

Saccharomyces cerevisiae is exposed to freeze-thaw stress in commercial processes, including frozen dough baking. Cell viability and fermentation activity after a freeze-thaw cycle were dramatically decreased due to freeze-thaw injury. Because this type of injury involves complex phenomena, the injury mechanisms are not fully understood. We examined freeze-thaw injury by indirect gene expression analysis during postthaw incubation after freeze-thaw treatment using DNA microarray profiling. The results showed that genes involved in the homeostasis of metal ions were frequently contained in genes that were upregulated, depending on the freezing period. We assessed the phenotype of deletion mutants of the metal ion homeostasis genes that exhibited freezing period-dependent upregulation and found that the strains with deletion of the MAC1 and CTR1 genes involved in copper ion homeostasis exhibited freeze-thaw sensitivity, suggesting that copper ion homeostasis is required for freeze-thaw tolerance. We found that supplementation with copper ions during postthaw incubation increased intracellular superoxide dismutase activity and intracellular levels of reactive oxygen species were decreased. Moreover, cell viability was increased by supplementation with copper ions. These results suggest that insufficiency of copper ion homeostasis may be one of the causes of freeze-thaw injury.

Spectator Ions ARE Important! A Kinetic Study of the Copper-Aluminum Displacement Reaction

ERIC Educational Resources Information Center

Sobel, Sabrina G.; Cohen, Skyler

2010-01-01

Surprisingly, spectator ions are responsible for unexpected kinetics in the biphasic copper(II)-aluminum displacement reaction, with the rate of reaction dependent on the identity of the otherwise ignored spectator ions. Application of a published kinetic analysis developed for a reaction between a rotating Al disk and a Cu(II) ion solution to the…

Precursor Ion Scan Mode-Based Strategy for Fast Screening of Polyether Ionophores by Copper-Induced Gas-Phase Radical Fragmentation Reactions.

PubMed

Crevelin, Eduardo J; Possato, Bruna; Lopes, João L C; Lopes, Norberto P; Crotti, Antônio E M

2017-04-04

The potential of copper(II) to induce gas-phase fragmentation reactions in macrotetrolides, a class of polyether ionophores produced by Streptomyces species, was investigated by accurate-mass electrospray tandem mass spectrometry (ESI-MS/MS). Copper(II)/copper(I) transition directly induced production of diagnostic acylium ions with m/z 199, 185, 181, and 167 from α-cleavages of [macrotetrolides + Cu] 2+ . A UPLC-ESI-MS/MS methodology based on the precursor ion scan of these acylium ions was developed and successfully used to identify isodinactin (1), trinactin (2), and tetranactin (3) in a crude extract of Streptomyces sp. AMC 23 in the precursor ion scan mode. In addition, copper(II) was also used to induce radical fragmentation reactions in the carboxylic acid polyether ionophore nigericin. The resulting product ions with m/z 755 and 585 helped to identify nigericin in a crude extract of Streptomyces sp. Eucal-26 by means of precursor ion scan experiments, demonstrating that copper-induced fragmentation reactions can potentially identify different classes of polyether ionophores rapidly and selectively.

ELECTROLYSIS AND ION EXCHANGE FOR THE IN PROCESS RECYCLING OF COPPER FROM SEMI-CONDUCTOR PROCESSING SOLUTIONS

EPA Science Inventory

The objectives of the study are to develop an understanding of the electrodeposition of copper onto extended-area electrodes, and of the adsorption/desorption of copper onto ion exchange resins with a high affinity for copper. The principles elucidated in this work will pave the ...

IDM release behavior and surface characteristics of the novel Cu/IDM/LDPE nanocomposite for intrauterine device.

PubMed

Yang, Zhihong; Xie, Changsheng; Xiang, Hua; Feng, Jinqing; Xia, Xianping; Cai, Shuizhou

2009-03-01

Copper/indomethacin/low-density polyethylene (Cu/IDM/LDPE) nanocomposite was prepared as a novel material for intra-uterine device (IUD). IDM release profile of the nanocomposite was investigated by using spectrophotometer. The results show that IDM release rate of Cu/IDM/LDPE nanocomposite is higher in simulated uterine solution than that in methanol, confirming that the release process of IDM is dominated mainly by pore diffusion. The decrease in copper particle size and the increase in copper mass content all accelerate IDM release, indicating that IDM release rate can be adjusted by changing copper loading or copper particle size. The surface of the incubated nanocomposite was characterized by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray microanalysis. A few deposits composed of P, Cl, Ca, Cu and O were observed on the nanocomposite surface, which may be related to the presence of IDM particles with large particle size.

Incorporation of copper nanoparticles into paper for point-of-use water purification

PubMed Central

Smith, James A.

2014-01-01

As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 minutes and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1 ppm). PMID:25014431

Regulation of copper and iron homeostasis by metal chelators: a possible chemotherapy for Alzheimer's disease.

PubMed

Robert, Anne; Liu, Yan; Nguyen, Michel; Meunier, Bernard

2015-05-19

With the increase of life expectancy of humans in more than two-thirds of the countries in the World, aging diseases are becoming the frontline health problems. Alzheimer's disease (AD) is now one of the major challenges in drug discovery, since, with the exception of memantine in 2003, all clinical trials with drug candidates failed over the past decade. If we consider that the loss of neurons is due to a high level of oxidative stress produced by nonregulated redox active metal ions like copper linked to amyloids of different sizes, regulation of metal homeostasis is a key target. The difficulty for large copper-carrier proteins to directly extract copper ions from metalated amyloids might be considered as being at the origin of the rupture of the copper homeostasis regulation in AD brains. So, there is an urgent need for new specific metal chelators that should be able to regulate the homeostasis of metal ions, specially copper and iron, in AD brains. As a consequence of that concept, chelators promoting metal excretion from brain are not desired. One should favor ligands able to extract copper ions from sinks (amyloids being the major one) and to transfer these redox-active metal ions to copper-carrier proteins or copper-containing enzymes. Obviously, the affinity of these chelators for the metal ion should not be a sufficient criterion, but the metal specificity and the ability of the chelators to release the metal under specific biological conditions should be considered. Such an approach is still largely unexplored. The requirements for the chelators are very high (ability to cross the brain-blood barrier, lack of toxicity, etc.), few chemical series were proposed, and, among them, biochemical or biological data are scarce. As a matter of fact, the bioinorganic pharmacology of AD represents less than 1% of all articles dedicated to AD drug research. The major part of these articles deals with an old and rather toxic drug, clioquinol and related analogs, that

Effects of light and copper ions on volatile aldehydes of milk and milk fractions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeno, W.; Bassette, R.; Crang, R.E.

1988-09-01

Raw, laboratory-pasteurized and plant-pasteurized homogenized milks were exposed to copper ions (5 ppm), to sunlight or fluorescent light and the effects determined on the composition of volatile aldehydes. The greatest change due to copper treatment was an increase in n-hexanal; acetaldehyde showed the least response in each of the sources of milk. The responses were similar from all three sources of milk with laboratory-pasteurized milk samples showing the greatest responses for each aldehyde analyzed. Similar milk samples exposed to sunlight also showed an increase in volatile aldehydes from all milk sources but with the greatest response being acetaldehyde and n-pentanalmore » components. The milk fraction most susceptible to changes in the presence of light was neutralized whey, whereas resuspended cream was most susceptible to copper exposure. Overall, dialyzed whey appeared to be influenced more than other milk fractions by both light and copper ions.« less

New biosensor for detection of copper ions in water based on immobilized genetically modified yeast cells.

PubMed

Vopálenská, Irena; Váchová, Libuše; Palková, Zdena

2015-10-15

Contamination of water by heavy metals represents a potential risk for both aquatic and terrestrial organisms, including humans. Heavy metals in water resources can come from various industrial activities, and drinking water can be ex-post contaminated by heavy metals such as Cu(2+) from house fittings (e.g., water reservoirs) and pipes. Here, we present a new copper biosensor capable of detecting copper ions at concentrations of 1-100 μM. This biosensor is based on cells of a specifically modified Saccharomyces cerevisiae strain immobilized in alginate beads. Depending on the concentration of copper, the biosensor beads change color from white, when copper is present in concentrations below the detection limit, to pink or red based on the increase in copper concentration. The biosensor was successfully tested in the determination of copper concentrations in real samples of water contaminated with copper ions. In contrast to analytical methods or other biosensors based on fluorescent proteins, the newly designed biosensor does not require specific equipment and allows the quick detection of copper in many parallel samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Economic booms and risky sexual behavior: evidence from Zambian copper mining cities.

PubMed

Wilson, Nicholas

2012-12-01

Existing studies suggest that individual and household level economic shocks affect the demand for and supply of risky sex. However, little evidence exists on the effects of an aggregate shock on equilibrium risky sexual behavior. This paper examines the effects of the early twenty-first century copper boom on risky sexual behavior in Zambian copper mining cities. The results suggest that the copper boom substantially reduced rates of transactional sex and multiple partnerships in copper mining cities. These effects were partly concentrated among young adults and copper boom induced in-migration to mining cities appears to have contributed to these reductions. Copyright © 2012. Published by Elsevier B.V.

Do soft drinks affect metal ions release from orthodontic appliances?

PubMed

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

2015-01-01

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

Investigating the role of ion-pair strategy in regulating nicotine release from patch: Mechanistic insights based on intermolecular interaction and mobility of pressure sensitive adhesive.

PubMed

Li, Qiaoyun; Wan, Xiaocao; Liu, Chao; Fang, Liang

2018-07-01

The aim of this study was to prepare a drug-in-adhesive patch of nicotine (NIC) and use ion-pair strategy to regulate drug delivery rate. Moreover, the mechanism of how ion-pair strategy regulated drug release was elucidated at molecular level. Formulation factors including pressure sensitive adhesives (PSAs), drug loading and counter ions (C 4 , C 6 , C 8 , C 10 , and C 12 ) were screened. In vitro release experiment and in vitro transdermal experiment were conducted to determine the rate-limiting step in drug delivery process. FT-IR and molecular modeling were used to characterize the interaction between drug and PSA. Thermal analysis and rheology study were conducted to investigate the mobility variation of PSA. The optimized patch prepared with NIC-C 8 had the transdermal profile fairly close to that of the commercial product (p > 0.05). The release rate constants (k) of NIC, NIC-C 4 and NIC-C 10 were 21.1, 14.4 and 32.4, respectively. Different release rates of NIC ion-pair complexes were attributed to the dual effect of ion-pair strategy on drug release. On one hand, ion-pair strategy enhanced the interaction between drug and PSA, which inhibited drug release. On the other hand, using ion-pair strategy improved the mobility of PSA, which facilitated drug release. Drug release behavior was determined by combined effect of two aspects above. These conclusions provided a new idea for us to regulate drug release behavior from patch. Copyright © 2018 Elsevier B.V. All rights reserved.

Copper Ion from Cu2O Crystal Induces AMPK-Mediated Autophagy via Superoxide in Endothelial Cells

PubMed Central

Seo, Youngsik; Cho, Young-Sik; Huh, Young-Duk; Park, Heonyong

2016-01-01

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions (Cu+ and Cu2+), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped Cu2O and CuO crystals were prepared to test the role of the two different ions, Cu+ and Cu2+, respectively. The Cu2O crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The Cu2O crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. Cu2O crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit Cu2O-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of Cu+ ions in the vascular system, where Cu+ induces autophagy while Cu2+ has no detected effect. PMID:26743904

A porous Cu/LDPE composite for copper-containing intrauterine contraceptive devices.

PubMed

Zhang, Weiwei; Xia, Xianping; Qi, Cheng; Xie, Changsheng; Cai, Shuizhou

2012-02-01

To improve the rates of both cupric ion release and the utilization of copper in non-porous copper/low-density polyethylene (Cu/LDPE) composite, a porous Cu/LDPE composite is proposed and developed in the present work. Here 2,5-di-tert-butylhydroquinone was chosen as the porogen, ethyl acetate was chosen as the solvent for extraction, and the porous Cu/LDPE composite was obtained by using injection molding and the particulate leaching method. After any residual ethyl acetate remaining inside the porous Cu/LDPE composite had been removed by vacuum drying, the composite was characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and absorption measurement. For comparison, a non-porous Cu/LDPE composite was also characterized in the same way. The results show that the porous structure was successfully introduced into the polymeric base of the non-porous Cu/LDPE composite, and the porous Cu/LDPE composite is a simple hybrid of copper particles and porous LDPE. The results also show that the introduction of a porous structure can improve the cupric ion release rate of the non-porous Cu/LDPE composite with a certain content of copper particles, indicating that the utilization rate of copper can be improved either the introduction of a porous structure, and that the porous Cu/LDPE composite is another promising material for copper-containing intrauterine devices. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect and interactions of commercial additives and chloride ion in copper electrowinning

NASA Astrophysics Data System (ADS)

Cui, Wenyuan

This thesis is to understand and compare the effects and interactions of modified polysaccharide (HydroStar), polyacrylamide (Cyquest N-900) and chloride ion on copper electrowinning. A study of the nucleation and growth was conducted in a synthetic electrolyte (40 g/L Cu, 160 g/L H2SO 4, 20 mg/L Cl-) with the addition of HydroStar or Cyquest N-900 using potential step measurements. The current responses generated were compared to theoretical models of nucleation and growth mechanisms. The nucleation and growth mechanism changed as function of potential and the presence of organic additives. The nucleation and growth mechanisms were confirmed using scanning electron microscopy (SEM). At low overpotentials, electrodeposition from the electrolyte without additives proceeded by progressive nucleation with three-dimensional (3-D) growth. The addition of HydroStar produced smaller nuclei and changed the mechanism to progressive nucleation and 2-D growth. Cyquest N-900 used there appeared to be progressive nucleation with 2-D growth and polarize the cathodes. In addition, instantaneous nucleation under diffusion control occurred at high overpotentials. Chloride ion and its interaction with HydroStar and Cyquest N-900 were further characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The trends observed from Nyquist plots and equivalent circuit models were consistent with the CV results. Chloride, on its own, depolarized copper electrodeposition, while chloride ion associated with Cyquest N-900 inhibited the reaction. It is proposed that Cl- acted as a bridging ligand between copper and Cyquest N-900. The addition of HydroStar depolarized copper deposition, but it did not interact with.

Glassy carbon electrode modified with polyanilne/ethylenediamine for detection of copper ions

NASA Astrophysics Data System (ADS)

Patil, Harshada K.; Deshmukh, Megha A.; Bodkhe, Gajanan A.; Shirsat, Mahendra D.

2018-05-01

Increasing water pollution is having high concern, since it creates the threats to all leaving organisms of existence. Industrial sewages have not only polluted the main stream lines of water, also the ground level water is having serious contaminations. Heavy metal ions are the pollutants which are not degradable and can be accumulated on living things ultimately the excess accumulation results into the serious concerns. Therefore, it is necessary to develop the sensors which can detect the heavy metal ions up to its maximum contamination limits. Conducting polymers are the materials which possess large application spectra. This investigation reports the electrochemically synthesized polyaniline (PANI) for modification of glassy carbon electrode (GCE). Ethylenediamine (EDA) - chelating ligand used for the modification of polyaniline so as to inculcate the selectivity toward copper ions Cu (II). The electrochemical cyclic voltammetry (CV) was used for the study of redox characteristics of PANI and influence of EDA modification. The result of CV has shown the reduced oxidation and reduction peak currents after modification indicating the domination of EDA. GCE modified with PANI/EDA was then employed for the detection of divalent copper ions and have shown the affinity toward Cu ions. The detection limit achieved was equal to 10mg/lit.

Chitosan/alginate multilayer film for controlled release of IDM on Cu/LDPE composite intrauterine devices.

PubMed

Tian, Kuan; Xie, Changsheng; Xia, Xianping

2013-09-01

To reduce such side effects as pain and bleeding caused by copper-containing intrauterine device (Cu-IUD), a novel medicated intrauterine device, which is coated with an indomethacin (IDM) delivery system on the surface of copper/low-density polyethylene (Cu/LDPE) composite intrauterine device, has been proposed and developed in the present work. The IDM delivery system is a polyelectrolyte multilayer film, which is composed of IDM containing chitosan and alginate layer by layer, is prepared by using self-assembled polyelectrolyte multilayer method, and the number of the layers of this IDM containing chitosan/alginate multilayer film can be tailored by controlling the cyclic repetition of the deposition process. After the IDM containing chitosan/alginate multilayer film is obtained on the surface of Cu/LDPE composite intrauterine device, its release behavior of both IDM and cupric ion has been studied in vitro. The results show that the release duration of IDM increase with the increasing of thickness of the IDM containing chitosan/alginate multilayer film, and the initial burst release of cupric ion cannot be found in this novel medicated Cu/LDPE composite IUD. These results can be applied to guide the design of novel medicated Cu-IUD with minimal side effects for the future clinical use. Copyright © 2013 Elsevier B.V. All rights reserved.

Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities

NASA Astrophysics Data System (ADS)

Hahn, C.; Hans, M.; Hein, C.; Mancinelli, R. L.; Mücklich, F.; Wirth, R.; Rettberg, P.; Hellweg, C. E.; Moeller, R.

2017-12-01

Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of

Incorporation of copper nanoparticles into paper for point-of-use water purification.

PubMed

Dankovich, Theresa A; Smith, James A

2014-10-15

As a cost-effective alternative to silver nanoparticles, we have investigated the use of copper nanoparticles in paper filters for point-of-use water purification. This work reports an environmentally benign method for the direct in situ preparation of copper nanoparticles (CuNPs) in paper by reducing sorbed copper ions with ascorbic acid. Copper nanoparticles were quickly formed in less than 10 min and were well distributed on the paper fiber surfaces. Paper sheets were characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and atomic absorption spectroscopy. Antibacterial activity of the CuNP sheets was assessed for by passing Escherichia coli bacteria suspensions through the papers. The effluent was analyzed for viable bacteria and copper release. The CuNP papers with higher copper content showed a high bacteria reduction of log 8.8 for E. coli. The paper sheets containing copper nanoparticles were effective in inactivating the test bacteria as they passed through the paper. The copper levels released in the effluent water were below the recommended limit for copper in drinking water (1 ppm). Copyright © 2014 Elsevier Ltd. All rights reserved.

The Extracellular Domain of Human High Affinity Copper Transporter (hNdCTR1), Synthesized by E. coli Cells, Chelates Silver and Copper Ions In Vivo.

PubMed

Sankova, Tatiana P; Orlov, Iurii A; Saveliev, Andrey N; Kirilenko, Demid A; Babich, Polina S; Brunkov, Pavel N; Puchkova, Ludmila V

2017-11-03

There is much interest in effective copper chelators to correct copper dyshomeostasis in neurodegenerative and oncological diseases. In this study, a recombinant fusion protein for expression in Escherichia coli cells was constructed from glutathione-S-transferase (GST) and the N-terminal domain (ectodomain) of human high affinity copper transporter CTR1 (hNdCTR1), which has three metal-bound motifs. Several biological properties of the GST-hNdCTR1 fusion protein were assessed. It was demonstrated that in cells, the protein was prone to oligomerization, formed inclusion bodies and displayed no toxicity. Treatment of E. coli cells with copper and silver ions reduced cell viability in a dose- and time-dependent manner. Cells expressing GST-hNdCTR1 protein demonstrated resistance to the metal treatments. These cells accumulated silver ions and formed nanoparticles that contained AgCl and metallic silver. In this bacterial population, filamentous bacteria with a length of about 10 µm were often observed. The possibility for the fusion protein carrying extracellular metal binding motifs to integrate into the cell's copper metabolism and its chelating properties are discussed.

Interactions of flavonoids with iron and copper ions: a mechanism for their antioxidant activity.

PubMed

Mira, Lurdes; Fernandez, M Tereza; Santos, Marta; Rocha, Rui; Florêncio, M Helena; Jennings, Keith R

2002-11-01

The metal chelating properties of flavonoids suggest that they may play a role in metal-overload diseases and in all oxidative stress conditions involving a transition metal ion. A detailed study has been made of the ability of flavonoids to chelate iron (including Fe3+) and copper ions and its dependence of structure and pH. The acid medium may be important in some pathological conditions. In addition, the ability of flavonoids to reduce iron and copper ions and their activity-structure relationships were also investigated. To fulfill these objectives, flavones (apigenin, luteolin, kaempferol, quercetin, myricetin and rutin), isoflavones (daidzein and genistein), flavanones (taxifolin, naringenin and naringin) and a flavanol (catechin) were investigated. All flavonoids studied show higher reducing capacity for copper ions than for iron ions. The flavonoids with better Fe3+ reducing activity are those with a 2,3-double bond and possessing both the catechol group in the B-ring and the 3-hydroxyl group. The copper reducing activity seems to depend largely on the number of hydroxyl groups. The chelation studies were carried out by means of ultraviolet spectroscopy and electrospray ionisation mass spectrometry. Only flavones and the flavanol catechin interact with metal ions. At pH 7.4 and pH 5.5 all flavones studied appear to chelate Cu2+ at the same site, probably between the 5-hydroxyl and the 4-oxo groups. Myricetin and quercetin, however, at pH 7.4, appear to chelate Cu2+ additionally at the ortho-catechol group, the chelating site for catechin with Cu2+ at pH 7.4. Chelation studies of Fe3+ to flavonoids were investigated only at pH 5.5. Only myricetin and quercetin interact strongly with Fe3+, complexation probably occurring again between the 5-hydroxyl and the 4-oxo groups. Their behaviour can be explained by their ability to reduce Fe3+ at pH 5.5, suggesting that flavonoids reduce Fe3+ to Fe2+ before association.

COPPER CORROSION RESEARCH UPDATE

EPA Science Inventory

Copper release and corrosion related issues continue to be important to many water systems. The objective of this presentation is to discuss the current state of copper research at the USEPA. Specifically, the role of aging on copper release, use of phosphates for copper corrosio...

Pure and Oxidized Copper Materials as Potential Antimicrobial Surfaces for Spaceflight Activities.

PubMed

Hahn, C; Hans, M; Hein, C; Mancinelli, R L; Mücklich, F; Wirth, R; Rettberg, P; Hellweg, C E; Moeller, R

2017-12-01

Microbial biofilms can lead to persistent infections and degrade a variety of materials, and they are notorious for their persistence and resistance to eradication. During long-duration space missions, microbial biofilms present a danger to crew health and spacecraft integrity. The use of antimicrobial surfaces provides an alternative strategy for inhibiting microbial growth and biofilm formation to conventional cleaning procedures and the use of disinfectants. Antimicrobial surfaces contain organic or inorganic compounds, such as antimicrobial peptides or copper and silver, that inhibit microbial growth. The efficacy of wetted oxidized copper layers and pure copper surfaces as antimicrobial agents was tested by applying cultures of Escherichia coli and Staphylococcus cohnii to these metallic surfaces. Stainless steel surfaces were used as non-inhibitory control surfaces. The production of reactive oxygen species and membrane damage increased rapidly within 1 h of exposure on pure copper surfaces, but the effect on cell survival was negligible even after 2 h of exposure. However, longer exposure times of up to 4 h led to a rapid decrease in cell survival, whereby the survival of cells was additionally dependent on the exposed cell density. Finally, the release of metal ions was determined to identify a possible correlation between copper ions in suspension and cell survival. These measurements indicated a steady increase of free copper ions, which were released indirectly by cells presumably through excreted complexing agents. These data indicate that the application of antimicrobial surfaces in spaceflight facilities could improve crew health and mitigate material damage caused by microbial contamination and biofilm formation. Furthermore, the results of this study indicate that cuprous oxide layers were superior to pure copper surfaces related to the antimicrobial effect and that cell density is a significant factor that influences the time dependence of

Enhancement in sensitivity of copper sulfide thin film ammonia gas sensor: Effect of swift heavy ion irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagade, Abhay Abhimanyu; Sharma, Ramphal; Department of Chemistry, Hanyang University, Sungdong-Ku, Haengdang-dong 17, Seoul 133-791

2009-02-15

The studies are carried out on the effect of swift heavy ion (SHI) irradiation on surface morphology and electrical properties of copper sulfide (Cu{sub x}S) thin films with three different chemical compositions (x values). The irradiation experiments have been carried out on Cu{sub x}S films with x=1.4, 1.8, and 2 by 100 MeV gold heavy ions at room temperature. These as-deposited and irradiated thin films have been used to detect ammonia gas at room temperature (300 K). The SHI irradiation treatment on x=1.4 and 1.8 copper sulfide films enhances the sensitivity of the gas sensor. The results are discussed consideringmore » high electronic energy deposition by 100 MeV gold heavy ions in a matrix of copper sulfide.« less

A copper ion-selective electrode with high selectivity prepared by sol-gel and coated wire techniques.

PubMed

Mazloum Ardakani, M; Salavati-Niasari, M; Khayat Kashani, M; Ghoreishi, S M

2004-03-01

A sol-gel electrode and a coated wire ion-selective poly(vinyl chloride) membrane, based on thiosemicarbazone as a neutral carrier, were successfully developed for the detection of Cu (II) in aqueous solutions. The sol-gel electrode and coated electrode exhibited linear response with Nernstian slopes of 29.2 and 28.1 mV per decade respectively, within the copper ion concentration ranges 1.0 x 10(-5) - 1.0 x 10(-1) M and 6.0 x 10(-6) - 1.0 x 10(-1) M for coated and sol-gel sensors. The coated and sol-gel electrodes show detection limits of 3.0 x 10(-6) and 6.0 x 10(-6) M respectively. The electrodes exhibited good selectivities for a number of alkali, alkaline earth, transition and heavy metal ions. The proposed electrodes have response times ranging from 10-50 s to achieve a 95% steady potential for Cu2+ concentration. The electrodes are suitable for use in aqueous solutions over a wide pH range (4-7.5). Applications of these electrodes for the determination of copper in real samples, and as an indicator electrode for potentiometric titration of Cu2+ ion using EDTA, are reported. The lifetimes of the electrodes were tested over a period of six months to investigate their stability. No significant change in the performance of the sol-gel electrode was observed over this period, but after two months the coated wire copper-selective electrode exhibited a gradual decrease in the slope. The selectivity of the sol-gel electrode was found to be better than that of the coated wire copper-selective electrode. Based on these results, a novel sol-gel copper-selective electrode is proposed for the determination of copper, and applied to real sample assays.

Copper import in Escherichia coli by the yersiniabactin metallophore system

PubMed Central

Koh, Eun-Ik; Robinson, Anne E.; Bandara, Nilantha; Rogers, Buck E.; Henderson, Jeffrey P.

2017-01-01

Copper plays a dual role as nutrient and toxin during bacterial infections. While uropathogenic Escherichia coli (UPEC) strains can use the copper-binding metallophore yersiniabactin (Ybt) to resist copper toxicity, Ybt also converts bioavailable copper to Cu(II)-Ybt in low copper conditions. Although E. coli have long been considered to lack a copper import pathway, we observed Ybt-mediated copper import in UPEC using canonical Fe(III)-Ybt transport proteins. UPEC removed copper from Cu(II)-Ybt with subsequent re-export of metal-free Ybt to the extracellular space. Copper released through this process became available to an E. coli cuproenzyme (the amine oxidase TynA), linking this import pathway to a nutrient acquisition function. Ybt-expressing E. coli thus engage in nutritional passivation, a strategy of minimizing a metal ion's toxicity while preserving its nutritional availability. Copper acquisition through this process may contribute to the marked virulence defect of Ybt transport-deficient UPEC. PMID:28759019

Rechargeable dental adhesive with calcium phosphate nanoparticles for long-term ion release

PubMed Central

Zhang, Ling; Weir, Michael D.; Hack, Gary; Fouad, Ashraf F.; Xu, Hockin H. K.

2015-01-01

Objectives The tooth-resin bond is the weak link of restoration, with secondary caries as a main reason for failure. Calcium phosphate-containing resins are promising for remineralization; however, calcium (Ca) and phosphate (P) ion releases last only a couple of months. The objectives of this study were to develop the first rechargeable CaP bonding agent and investigate the key factors that determine CaP ion recharge and re-release. Methods Nanoparticles of amorphous calcium phosphate (NACP) were synthesized. Pyromellitic glycerol dimethacrylate (PMGDM), ethoxylated bisphenol-A dimethacrylate (EBPADMA), 2-hydroxyethyl methacrylate (HEMA), and bisphenol-A glycidyl dimethacrylate (BisGMA) were used to synthesize three adhesives (denoted PE, PEH and PEHB). NACP were mixed into adhesive at 0–30% by mass. Dentin shear bond strengths were measured. Adhesive specimens were tested for Ca and P initial ion release. Then the ion-exhausted specimens were immersed in Ca and P solution to recharge the specimens, and the recharged specimens were then used to measure ion re-release for 7 days as one cycle. Then these specimens were again recharged and the re-release was measured for 7 days as the second cycle. Three recharge/re-release cycles were tested. Results PEHB had the highest dentin bond strength (p<0.05). Increasing NACP content from 0 to 30% did not affect dentin bond strength (p>0.1), but increased CaP release and re-release (p<0.05). PEHB-NACP had the greatest recharge/re-release, and PE-NACP had the least (p<0.05). Ion release remained high and did not decrease with increasing the number of recharge/re-release cycles (p>0.1). After the third cycle, specimens without further recharge had continuous CaP ion release for 2–3 weeks. Significance Rechargeable CaP bonding agents were developed for the first time to provide long-term Ca and P ions to promote remineralization and reduce caries. Incorporation of NACP into adhesive had no negative effect on dentin bond

Reactivity of food phenols with iron and copper ions: binding, dioxygen activation and oxidation mechanisms.

PubMed

Nkhili, Ezzohra; Loonis, Michèle; Mihai, Simona; El Hajji, Hakima; Dangles, Olivier

2014-06-01

In this work, the affinity of common dietary phenols (gallic acid, caffeic acid, catechin, and rutin) for iron and copper ions was quantitatively investigated in neutral phosphate buffer as well as the reactivity of the complexes toward dioxygen. Contrasting behaviors were observed: because of the competing phosphate ions, Fe(III) binding is much slower than Fe(II) binding, which is rapidly followed by autoxidation of Fe(II) into Fe(III). With both ions, O2 consumption and H2O2 production are modest and the phenolic ligands are only slowly oxidized. By contrast, metal-phenol binding is fast with both Cu(I) and Cu(II). With Cu(I), O2 consumption and H2O2 production are very significant and the phenolic ligands are rapidly oxidized into a complex mixture of oligomers. The corresponding mechanism with Cu(II) is hampered by the preliminary rate-determining step of Cu(II) reduction by the phenols. The consequences of these findings for the stability and antioxidant activity of plant phenols are discussed.

Identification of Two Conserved Residues Involved in Copper Release from Chloroplast PIB-1-ATPases*

PubMed Central

Sautron, Emeline; Giustini, Cécile; Dang, ThuyVan; Moyet, Lucas; Salvi, Daniel; Crouzy, Serge; Rolland, Norbert; Catty, Patrice; Seigneurin-Berny, Daphné

2016-01-01

Copper is an essential transition metal for living organisms. In the plant model Arabidopsis thaliana, half of the copper content is localized in the chloroplast, and as a cofactor of plastocyanin, copper is essential for photosynthesis. Within the chloroplast, copper delivery to plastocyanin involves two transporters of the PIB-1-ATPases subfamily: HMA6 at the chloroplast envelope and HMA8 in the thylakoid membranes. Both proteins are high affinity copper transporters but share distinct enzymatic properties. In the present work, the comparison of 140 sequences of PIB-1-ATPases revealed a conserved region unusually rich in histidine and cysteine residues in the TMA-L1 region of eukaryotic chloroplast copper ATPases. To evaluate the role of these residues, we mutated them in HMA6 and HMA8. Mutants of interest were selected from phenotypic tests in yeast and produced in Lactococcus lactis for further biochemical characterizations using phosphorylation assays from ATP and Pi. Combining functional and structural data, we highlight the importance of the cysteine and the first histidine of the CX3HX2H motif in the process of copper release from HMA6 and HMA8 and propose a copper pathway through the membrane domain of these transporters. Finally, our work suggests a more general role of the histidine residue in the transport of copper by PIB-1-ATPases. PMID:27493208

Microwave plasma torch mass spectrometry for the direct detection of copper and molybdenum ions in aqueous liquids.

PubMed

Xiong, Xiaohong; Jiang, Tao; Zhou, Runzhi; Wang, Shangxian; Zou, Wei; Zhu, Zhiqiang

2016-05-01

Microwave plasma torch (MPT) is a simple and low power-consumption ambient ion source. And the MPT Mass spectra of many metal elements usually exhibit some novel features different from their inductively coupled plasma (ICP) mass spectra, which may be helpful for metal element analysis. Here, we presented the results about the MPT mass spectra of copper and molybdenum elements by a linear ion trap mass spectrometer (LTQ). The generated copper or molybdenum contained ions in plasma were characterized further in collision-induced dissociated (CID) experiments. These researches built a novel, direct and sensitive method for the direct analysis of trace levels of copper and molybdenum in aqueous liquids. Quantitative results showed that the limit of detection (LOD) by using MS(2) procedure was estimated to be 0.265 µg/l (ppb) for copper and 0.497 µg/l for molybdenum. The linear dynamics ranges cover at least 2 orders of magnitude and the analysis of a single aqueous sample can be completed in 5-6 min with a reasonable semi-quantitative sense. Two practical aqueous samples, milk and urine, were also analyzed qualitatively with reasonable recovery rates and RSD. These experimental data demonstrated that the MPT MS is able to turn into a promising and hopeful tool in field analysis of copper and molybdenum ions in water and some aqueous media, and can be applied in many fields, such as environmental controlling, hydrogeology, and water quality inspection. Moreover, MPT MS could also be used as the supplement of ICP-MS for the rapid and in-situ analysis of metal ions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Sensitive detection of mercury and copper ions by fluorescent DNA/Ag nanoclusters in guanine-rich DNA hybridization

NASA Astrophysics Data System (ADS)

Peng, Jun; Ling, Jian; Zhang, Xiu-Qing; Bai, Hui-Ping; Zheng, Liyan; Cao, Qiu-E.; Ding, Zhong-Tao

2015-02-01

In this work, we designed a new fluorescent oligonucleotides-stabilized silver nanoclusters (DNA/AgNCs) probe for sensitive detection of mercury and copper ions. This probe contains two tailored DNA sequence. One is a signal probe contains a cytosine-rich sequence template for AgNCs synthesis and link sequence at both ends. The other is a guanine-rich sequence for signal enhancement and link sequence complementary to the link sequence of the signal probe. After hybridization, the fluorescence of hybridized double-strand DNA/AgNCs is 200-fold enhanced based on the fluorescence enhancement effect of DNA/AgNCs in proximity of guanine-rich DNA sequence. The double-strand DNA/AgNCs probe is brighter and stable than that of single-strand DNA/AgNCs, and more importantly, can be used as novel fluorescent probes for detecting mercury and copper ions. Mercury and copper ions in the range of 6.0-160.0 and 6-240 nM, can be linearly detected with the detection limits of 2.1 and 3.4 nM, respectively. Our results indicated that the analytical parameters of the method for mercury and copper ions detection are much better than which using a single-strand DNA/AgNCs.

Electrochemical determination of copper ions in spirit drinks using carbon paste electrode modified with biochar.

PubMed

Oliveira, Paulo Roberto; Lamy-Mendes, Alyne C; Rezende, Edivaltrys Inayve Pissinati; Mangrich, Antonio Sálvio; Marcolino, Luiz Humberto; Bergamini, Márcio F

2015-03-15

This work describes for first time the use of biochar as electrode modifier in combination with differential pulse adsorptive stripping voltammetric (DPAdSV) techniques for preconcentration and determination of copper (II) ions in spirit drinks samples (Cachaça, Vodka, Gin and Tequila). Using the best set of the experimental conditions a linear response for copper ions in the concentration range of 1.5 × 10(-6) to 3.1 × 10(-5) mol L(-1) with a Limit of Detection (LOD) of 4.0 × 10(-7) mol L(-1). The repeatability of the proposed sensor using the same electrode surface was measured as 3.6% and 6.6% using different electrodes. The effect of foreign species on the voltammetric response was also evaluated. Determination of copper ions content in different samples of spirit drinks samples was also realized adopting inductively coupled plasma optical emission spectroscopy (ICP-OES) and the results achieved are in agreement at a 95% of confidence level. Copyright © 2014 Elsevier Ltd. All rights reserved.

Scattered Ion Energetics for H atoms Impinging a Copper Surface

NASA Astrophysics Data System (ADS)

Defazio, J. N.; Stephen, T. M.; Peko, B. L.

2002-05-01

The energy loss and charge state of atomic hydrogen scattered from surfaces is important in a broad range of scientific endeavors. These include the charging of spacecraft, the detection of low energy neutrals in the space environment, energy transfer from magnetically confined plasmas and the modeling of low energy electric discharges. Measurements of scattered ions resulting from low energy (20 - 1000 eV) atomic hydrogen impacting a copper surface have been accomplished. Differential energy distributions and yields for H- and H+ resulting from these collisions are presented. The data show that the energy distributions develop a universal dependence, when scaled by the incident energy. These results are compared with studies involving incident hydrogen ions. For incident energies less than 100eV, there are obvious differences in the scattered ion energy distributions resulting from impacting atoms when compared to those resulting from ions.

Ca(2+) and OH(-) release of ceramsites containing anorthite and gehlenite prepared from waste lime mud.

PubMed

Qin, Juan; Yang, Chuanmeng; Cui, Chong; Huang, Jiantao; Hussain, Ahmad; Ma, Hailong

2016-09-01

Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca(2+) and OH(-) release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca(2+) and OH(-) were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca(2+) and OH(-) release compared with anorthite. The Ca(2+) release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca(2+) and OH(-) released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH=9.3-10.9) and the release of Ca(2+) was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy. Copyright © 2016. Published by Elsevier B.V.

Copper ions stimulate the proliferation of hepatic stellate cells via oxygen stress in vitro.

PubMed

Xu, San-qing; Zhu, Hui-yun; Lin, Jian-guo; Su, Tang-feng; Liu, Yan; Luo, Xiao-ping

2013-02-01

This study examined the effect of copper ions on the proliferation of hepatic stellate cells (HSCs) and the role of oxidative stress in this process in order to gain insight into the mechanism of hepatic fibrosis in Wilson's disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine (NAC) and buthionine sulfoximine (BSO) for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Western blotting were used to detect the mRNA and protein expression of platelet-derived growth factor receptor β subunit (PDGFβR), ELISA to determine the level of glutathione (GSH) and oxidized glutathione (GSSG), dichlorofluorescein assay to measure the level of reactive oxygen species (ROS), and lipid hydroperoxide assay to quantify the level of lipid peroxide (LPO). The results showed that copper sulfate over a certain concentration range could promote the proliferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 μmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGFβR was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenomenon could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

The Extracellular Domain of Human High Affinity Copper Transporter (hNdCTR1), Synthesized by E. coli Cells, Chelates Silver and Copper Ions In Vivo

PubMed Central

Sankova, Tatiana P.; Orlov, Iurii A.; Saveliev, Andrey N.; Kirilenko, Demid A.; Babich, Polina S.; Brunkov, Pavel N.; Puchkova, Ludmila V.

2017-01-01

There is much interest in effective copper chelators to correct copper dyshomeostasis in neurodegenerative and oncological diseases. In this study, a recombinant fusion protein for expression in Escherichia coli cells was constructed from glutathione-S-transferase (GST) and the N-terminal domain (ectodomain) of human high affinity copper transporter CTR1 (hNdCTR1), which has three metal-bound motifs. Several biological properties of the GST-hNdCTR1 fusion protein were assessed. It was demonstrated that in cells, the protein was prone to oligomerization, formed inclusion bodies and displayed no toxicity. Treatment of E. coli cells with copper and silver ions reduced cell viability in a dose- and time-dependent manner. Cells expressing GST-hNdCTR1 protein demonstrated resistance to the metal treatments. These cells accumulated silver ions and formed nanoparticles that contained AgCl and metallic silver. In this bacterial population, filamentous bacteria with a length of about 10 µm were often observed. The possibility for the fusion protein carrying extracellular metal binding motifs to integrate into the cell’s copper metabolism and its chelating properties are discussed. PMID:29099786

Synthesis and application of a highly selective copper ions fluorescent probe based on the coumarin group

NASA Astrophysics Data System (ADS)

He, Guangjie; Liu, Xiangli; Xu, Jinhe; Ji, Liguo; Yang, Linlin; Fan, Aiying; Wang, Songjun; Wang, Qingzhi

2018-02-01

A highly selective copper ions fluorescent probe based on the coumarin-type Schiff base derivative 1 (probe) was produced by condensation reaction between coumarin carbohydrazide and 1H-indazole-3-carbaldehyde. The UV-vis spectroscopy showed that the maximum absorption peak of compound 1 appeared at 439 nm. In the presence of Cu2 + ions, the maximum peak decreased remarkably compared with other physiological important metal ions and a new absorption peak at 500 nm appeared. The job's plot experiments showed that complexes of 1:2 binding mode were formed in CH3CN:HEPES (3:2, v/v) solution. Compound 1 exhibited a strong blue fluorescence. Upon addition of copper ions, the fluorescence gradually decreased and reached a plateau with the fluorescence quenching rate up to 98.73%. The detection limit for Cu2 + ions was estimated to 0.384 ppm. Fluorescent microscopy experiments demonstrated that probe 1 had potential to be used to investigate biological processes involving Cu2 + ions within living cells.

Zoledronate and Ion-releasing Resins Impair Dentin Collagen Degradation

PubMed Central

Tezvergil-Mutluay, A.; Seseogullari-Dirihan, R.; Feitosa, V.P.; Tay, F.R.; Watson, T.F.; Pashley, D.H.; Sauro, S.

2014-01-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. PMID:25074494

L-cysteine protected copper nanoparticles as colorimetric sensor for mercuric ions.

PubMed

Soomro, Razium A; Nafady, Ayman; Sirajuddin; Memon, Najma; Sherazi, Tufail H; Kalwar, Nazar H

2014-12-01

This report demonstrates a novel, simple and efficient protocol for the synthesis of copper nanoparticles in aqueous solution using L-cysteine as capping or protecting agent. UV-visible (UV-vis) spectroscopy was employed to monitor the LSPR band of L-cysteine functionalized copper nanoparticles (Cyst-Cu NPs) based on optimizing various reaction parameters. Fourier Transform Infrared (FTIR) spectroscopy provided information about the surface interaction between L-cysteine and Cu NPs. Transmission Electron Microscopy (TEM) confirmed the formation of fine spherical, uniformly distributed Cyst-Cu NPs with average size of 34 ± 2.1 nm. X-ray diffractometry (XRD) illustrated the formation of pure metallic phase crystalline Cyst-Cu NPs. As prepared Cyst-Cu NPs were tested as colorimetric sensor for determining mercuric (Hg(2+)) ions in an aqueous system. Cyst-Cu NPs demonstrated very sensitive and selective colorimetric detection of Hg(2+) ions in the range of 0.5 × 10(-6)-3.5 × 10(-6) mol L(-1) based on decrease in LSPR intensity as monitored by a UV-vis spectrophotometer. The developed sensor is simple, economic compared to those based on precious metal nanoparticles and sensitive to detect Hg(2+) ions with detection limit down to 4.3 × 10(-8) mol L(-1). The sensor developed in this work has a high potential for rapid and on-site detection of Hg(2+) ions. The sensor was successfully applied for assessment of Hg(2+) ions in real water samples collected from various locations of the Sindh River. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of citric acid modification of aspen wood on sorption of copper ion

Treesearch

James D. McSweeny; Roger M. Rowell; Soo Hong Min

2006-01-01

Milled aspen wood was thermochemically modified with citric acid for the purpose of improving the copper (Cu2+) ion sorption capacity of the wood when tested in 24-hour equilibrium batch tests. The wood-citric acid adducts provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ ion uptake of the modified wood compared with that...

Release of major ions during rigor mortis development in kid Longissimus dorsi muscle.

PubMed

Feidt, C; Brun-Bellut, J

1999-01-01

Ionic strength plays an important role in post mortem muscle changes. Its increase is due to ion release during the development of rigor mortis. Twelve alpine kids were used to study the effects of chilling and meat pH on ion release. Free ions were measured in Longissimus dorsi muscle by capillary electrophoresis after water extraction. All free ion concentrations increased after death, but there were differences between ions. Temperature was not a factor affecting ion release in contrast to ultimate pH value. Three release mechanisms are believed to coexist: a passive binding to proteins, which stops as pH decreases, an active segregation which stops as ATP disappears and the production of metabolites due to anaerobic glycolysis.

The Bone Building Blues: Self-hardening copper-doped calcium phosphate cement and its in vitro assessment against mammalian cells and bacteria.

PubMed

Rau, Julietta V; Wu, Victoria M; Graziani, Valerio; Fadeeva, Inna V; Fomin, Alexander S; Fosca, Marco; Uskoković, Vuk

2017-10-01

A blue calcium phosphate cement with optimal self-hardening properties was synthesized by doping whitlockite (β-TCP) with copper ions. The mechanism and the kinetics of the cement solidification process were studied using energy dispersive X-ray diffraction and it was found out that hardening was accompanied by the phase transition from TCP to brushite. Reduced lattice parameters in all crystallographic directions resulting from the rather low (1:180) substitution rate of copper for calcium was consistent with the higher ionic radius of the latter. The lower cationic hydration resulting from the partial Ca→Cu substitution facilitated the release of constitutive hydroxyls and lowered the energy of formation of TCP from the apatite precursor at elevated temperatures. Addition of copper thus effectively inhibited the formation of apatite as the secondary phase. The copper-doped cement exhibited an antibacterial effect, though exclusively against Gram-negative bacteria, including E. coli, P. aeruginosa and S. enteritidis. This antibacterial effect was due to copper ions, as demonstrated by an almost negligible antibacterial effect of the pure, copper-free cement. Also, the antibacterial activity of the copper-containing cement was significantly higher than that of its precursor powder. Since there was no significant difference between the kinetics of the release of copper from the precursor TCP powder and from the final, brushite phase of the hardened cement, this has suggested that the antibacterial effect was not solely due to copper ions, but due to the synergy between cationic copper and a particular phase and aggregation state of calcium phosphate. Though inhibitory to bacteria, the copper-doped cement increased the viability of human glial E297 cells, murine osteoblastic K7M2 cells and especially human primary lung fibroblasts. That this effect was also due to copper ions was evidenced by the null effect on viability increase exhibited by the copper

Removal of copper ions from aqueous solution by adsorption onto novel polyelectrolyte film-coated nanofibrous silk fibroin non-wovens

NASA Astrophysics Data System (ADS)

Zhou, Weitao; Huang, Haitao; Du, Shan; Huo, Yingdong; He, Jianxin; Cui, Shizhong

2015-08-01

In this approach, polyelectrolyte film-coated nanofibrous silk fibroin (SF) nonwovens were prepared from the alternate deposition of positively charged polyethylenimine (PEI) and negatively charged SF using electrostatic layer-by-layer (LBL) self-assembled technology. The composite membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometer. The SF-PEI multilayer-assembled nanofibers (less than five layers) were fine and uniform with the fiber diameter from 400 nm to 600 nm, and had very large surface area and high porosity (more than 70%). The amino groups of PEI were proved to be deposited onto SF nonwovens, which granted the coated nonwovens with potential applicability for copper ions adsorption. The PEI films coated SF substrate showed much higher copper ions adsorption capacity than that of ethanol treated SF nanofibers. Adding the number of PEI coated could enhance the Cu2+ adsorption capacity significantly. The maximum milligrams per gram of copper ions adsorbed reached 59.7 mg/g when the SF substrate was coated with 5 bilayers of SF-PEI. However, the copper ions adsorption capacity had no obvious change as the number of PEI continued to increase. These results suggest potential for PEL film-coated nanofibrous nonwovens as a new adsorbent for metal ions.

Zoledronate and ion-releasing resins impair dentin collagen degradation.

PubMed

Tezvergil-Mutluay, A; Seseogullari-Dirihan, R; Feitosa, V P; Tay, F R; Watson, T F; Pashley, D H; Sauro, S

2014-10-01

This study analyzed the amounts of solubilized telopeptides cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and C-terminal crosslinked telopeptide of type I collagen (CTX) derived from matrix-metalloproteinases (MMPs) and cysteine cathepsins (CTPs) subsequent to application of a filler-free (Res.A) or an ion-releasing resin (Res.B) to ethylenediaminetetraacetic acid (EDTA)-demineralized dentin with or without zoledronate-containing primer (Zol-primer) pre-treatment. The chemical modification induced following treatments and artificial saliva (AS) storage was also analyzed through attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Totally EDTA-demineralized specimens were infiltrated with Res.A or Res.B with or without Zol-primer pre-treatment, light-cured, and immersed in AS for up to 4 wk. ICTP release was reduced following infiltration with Res.B and further reduced when Res.B was used with Zol-primer; remarkable phosphate mineral uptake was attained after AS storage. CTX release was increased in Res.A- and Res.B-treated dentin. However, when Zol-primer was used with Res.A, the CTX release fell significantly compared to the other tested resin-infiltration methods. In conclusion, zoledronate offers an additional inhibitory effect to the ion-releasing resins in MMP-mediated collagen degradation. However, Zol-primer induces a modest reduction in CTX release only when used with resin-based systems containing no ion-releasing fillers. © International & American Associations for Dental Research.

Analysis of spectra of 3s-3p and 3p-3d transitions of highly-charged copper ions

NASA Astrophysics Data System (ADS)

Su, M. G.; Min, Q.; He, S. Q.; Wu, L.; Sun, R.; Ding, X. B.; Sun, D. X.

2017-08-01

Beam-foil excited spectra in the range of 160-360 Å from highly charged copper ions were identified with the aid of the National Institute of Standards and Technology Atomic Spectra Database and theoretical calculations with Cowan and Flexible Atomic Code (FAC) calculations. Spectra arising from 3s-3p and 3p-3d transitions of Cu13+-Cu22+ ions were considered. The ion fraction at an ion beam energy of 110 MeV was estimated from the equilibrium charge distribution of the fast ion beams after passing through the solid. The corresponding simulated spectra were in good agreement with the experimental result. Our Cowan and FAC calculation results should be useful for further spectral identification and lifetime measurements of highly charged copper ions.

Formation of copper precipitates in silicon

NASA Astrophysics Data System (ADS)

Flink, Christoph; Feick, Henning; McHugo, Scott A.; Mohammed, Amna; Seifert, Winfried; Hieslmair, Henry; Heiser, Thomas; Istratov, Andrei A.; Weber, Eicke R.

1999-12-01

The formation of copper precipitates in silicon was studied after high-temperature intentional contamination of p- and n-type FZ and Cz-grown silicon and quench to room temperature. With the Transient Ion Drift (TID) technique on p-type silicon a critical Fermi level position at EC-0.2 eV was found. Only if the Fermi level position, which is determined by the concentrations of the acceptors and the copper donors, surpasses this critical value precipitation takes place. If the Fermi level is below this level the supersaturated interstitial copper diffuses out. An electrostatic precipitation model is introduced that correlates the observed precipitation behavior with the electrical activity of the copper precipitates as detected with Deep Level Transient Spectroscopy (DLTS) on n-type and with Minority Carrier Transient Spectroscopy (MCTS) on p-type silicon.

Cyanide and Copper Recovery from Barren Solution of the Merrill Crowe Process

NASA Astrophysics Data System (ADS)

Parga, José R.; Valenzuela, Jesús L.; Díaz, J. A.

This paper is a brief overview of the role of inducing the nucleated precipitation of copper and cyanide in a flashtube serpentine reactor, using sodium sulfide as the precipitate and sulfuric acid as pH control. The results showed that pH had a great effect on copper cyanide removal efficiency and the optimum pH was about 3 to 3.5. At this pH value copper cyanide removal efficiency could be achieved above 97 and 99 %, when influent copper concentration ions were 650 and 900 ppm respectively. In this process the cyanide associated with the copper, zinc, iron cyanide complexes are released as HCN gas under strong acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide.

Home Plumbing Simulator for the Study of Copper and Lead Corrosion and Release, Disinfectant Demand, and Biofilm Activity - abstract

EPA Science Inventory

The corrosion of household or premise plumbing materials (such as copper, brass, and solder) and the metal release that results from that corrosion can cause numerous problems, ranging from “blue” water to copper pinhole leaks. If left untreated, these problems can lead to health...

Influence of copper ions on the viability and cytotoxicity of Pseudomonas aeruginosa under conditions relevant to drinking water environments.

PubMed

Dwidjosiswojo, Zenyta; Richard, Jessica; Moritz, Miriam M; Dopp, Elke; Flemming, Hans-Curt; Wingender, Jost

2011-11-01

Copper plumbing materials can be the source of copper ions in drinking water supplies. The aim of the current study was to investigate the influence of copper ions on the viability and cytotoxicity of the potential pathogen Pseudomonas aeruginosa that presents a health hazard when occurring in building plumbing systems. In batch experiments, exposure of P. aeruginosa (10(6)cells/mL) for 24h at 20°C to copper-containing drinking water from domestic plumbing systems resulted in a loss of culturability, while total cell numbers determined microscopically did not decrease. Addition of the chelator diethyldithiocarbamate (DDTC) to copper-containing water prevented the loss of culturability. When suspended in deionized water with added copper sulfate (10 μM), the culturability of P. aeruginosa decreased by more than 6 log units, while total cell counts, the concentration of cells with intact cytoplasmic membranes, determined with the LIVE/DEAD BacLight kit, and the number of cells with intact 16S ribosomal RNA, determined by fluorescent in situ hybridization, remained unchanged. When the chelator DDTC was added to copper-stressed bacteria, complete restoration of culturability was observed to occur within 14 d. Copper-stressed bacteria were not cytotoxic towards Chinese hamster ovary (CHO-9) cells, while untreated and resuscitated bacteria caused an almost complete decrease of the concentration of viable CHO-9 cells within 24 h. Thus, copper ions in concentrations relevant to drinking water in plumbing systems seem to induce a viable but non-culturable (VBNC) state in P. aeruginosa accompanied by a loss of culturability and cytotoxicity, and VBNC cells can regain both culturability and cytotoxicity, when copper stress is abolished. Copyright © 2011 Elsevier GmbH. All rights reserved.

Optical properties of ion beam textured metals. [using copper, silicon, aluminum, titanium and stainless steels

NASA Technical Reports Server (NTRS)

Hudson, W. R.; Weigand, A. J.; Mirtich, M. J.

1977-01-01

Copper, silicon, aluminum, titanium and 316 stainless steel were textured by 1000 eV xenon ions from an 8 cm diameter electron bombardment ion source. Simultaneously sputter-deposited tantalum was used to facilitate the development of the surface microstructure. Scanning electron microscopy of the ion textured surfaces revealed two types of microstructure. Copper, silicon, and aluminum developed a cone structure with an average peak-to-peak distance ranging from 1 micron for silicon to 6 microns for aluminum. Titanium and 316 stainless steel developed a serpentine ridge structure. The average peak-to-peak distance for both of these materials was 0.5 micron. Spectral reflectance was measured using an integrating sphere and a holraum reflectometer. Total reflectance for air mass 0 and 2, solar absorptance and total emittance normalized for a 425 K black body were calculated from the reflectance measurements.

Electrochemical Behavior of Pure Copper in Phosphate Buffer Solutions: A Comparison Between Micro- and Nano-Grained Copper

NASA Astrophysics Data System (ADS)

Imantalab, O.; Fattah-alhosseini, A.; Keshavarz, M. K.; Mazaheri, Y.

2016-02-01

In this work, electrochemical behavior of annealed (micro-) and nano-grained pure copper (fabricated by accumulative roll bonding process) in phosphate buffer solutions of various pH values ranging from 10.69 to 12.59 has been studied. Before any electrochemical measurements, evaluation of microstructure was obtained by optical microscope and transmission electron microscopy. To investigate the electrochemical behavior of the samples, the potentiodynamic polarization, Mott-Schottky analysis, and electrochemical impedance spectroscopy (EIS) were carried out. Potentiodynamic polarization plots and EIS measurements revealed that as a result of grain refinement, the passive behavior of the nano-grained sample was improved compared to that of annealed pure copper. Also, Mott-Schottky analysis indicated that the passive films behaved as p-type semiconductors and grain refinement did not change the semiconductor type of passive films.

Investigation of Industrial Polyurethane Foams Modified with Antimicrobial Copper Nanoparticles

PubMed Central

Sportelli, Maria Chiara; Picca, Rosaria Anna; Ronco, Roberto; Bonerba, Elisabetta; Tantillo, Giuseppina; Pollini, Mauro; Sannino, Alessandro; Valentini, Antonio; Cataldi, Tommaso R.I.; Cioffi, Nicola

2016-01-01

Antimicrobial copper nanoparticles (CuNPs) were electrosynthetized and applied to the controlled impregnation of industrial polyurethane foams used as padding in the textile production or as filters for air conditioning systems. CuNP-modified materials were investigated and characterized morphologically and spectroscopically, by means of Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). The release of copper ions in solution was studied by Electro-Thermal Atomic Absorption Spectroscopy (ETAAS). Finally, the antimicrobial activity of freshly prepared, as well as aged samples—stored for two months—was demonstrated towards different target microorganisms. PMID:28773665

Disulfiram and Copper Ions Kill Mycobacterium tuberculosis in a Synergistic Manner

PubMed Central

Dalecki, Alex G.; Haeili, Mehri; Shah, Santosh; Speer, Alexander; Niederweis, Michael; Kutsch, Olaf

2015-01-01

Tuberculosis is a severe disease affecting millions worldwide. Unfortunately, treatment strategies are hampered both by the prohibitively long treatment regimen and the rise of drug-resistant strains. Significant effort has been expended in the search for new treatments, but few options have successfully emerged, and new treatment modalities are desperately needed. Recently, there has been growing interest in the synergistic antibacterial effects of copper ions (CuII/I) in combination with certain small molecular compounds, and we have previously reported development of a drug screening strategy to harness the intrinsic bactericidal properties of CuII/I. Here, we describe the copper-dependent antimycobacterial properties of disulfiram, an FDA-approved and well-tolerated sobriety aid. Disulfiram was inhibitory to mycobacteria only in the presence of CuII/I and exerted its bactericidal activity well below the active concentration of CuII/I or disulfiram alone. No other physiologically relevant bivalent transition metals (e.g., FeII, NiII, MnII, and CoII) exhibited this effect. We demonstrate that the movement of the disulfiram-copper complex across the cell envelope is porin independent and can inhibit intracellular protein functions. Additionally, the complex is able to synergistically induce intracellular copper stress responses significantly more than CuII/I alone. Our data suggest that by complexing with disulfiram, CuII/I is likely allowed unfettered access to vulnerable intracellular components, bypassing the normally sufficient copper homeostatic machinery. Overall, the synergistic antibacterial activity of CuII/I and disulfiram reveals the susceptibility of the copper homeostasis system of Mycobacterium tuberculosis to chemical attacks and establishes compounds that act in concert with copper as a new class of bacterial inhibitors. PMID:26033731

Flotation of traces of silver and copper(II) ions with a methyl cellosolve solution of dithizone.

PubMed

Hiraide, M; Mizuike, A

1975-06-01

Microgram quantities of silver and copper(II) ions in aqueous solutions are collected on dithizone precipitates, which are then floated with the aid of small nitrogen bubbles. This separation technique has been successfully applied to the atomic-absorption spectrophotometric determination of down to a tenth ppm of silver and copper in high-purity lead and zinc metals.

Synthesis of silver nanoparticles stabilized with C-phycocyanin and for fluorimetric detection of copper ions

NASA Astrophysics Data System (ADS)

Wei, Nana; Hou, Yanhua; Lu, Zongbao; Yu, Huatong; Wang, Quanfu

2018-01-01

In this study, C-phycocyanin as protective agent, AgNO3 as raw material and NaBH4 as reducing agent synthesized C-phycocyanin-Ag nanoparticles (PC-AgNPs). The synthesis conditions of PC-AgNPs were determined by optimization. The maximum UV absorption peak of PC-AgNPs at 400 nm. The fluorescence excitation wavelength was 580 nm and the emission wavelength was 625 nm. PC-AgNPs was spherical in transmission electron microscope and the particles sizes were about 10-25 nm. In addition, fluorescence quenching was observed after adding copper ions to PC-AgNPs, which indicated that PC-AgNPs has potential applications in the detection of copper ions in diverse water environment.

Iron, Manganese and Copper Release from Synthetic Hydroxyapatite

NASA Technical Reports Server (NTRS)

Sutter, B.; Hossner, L. R.; Ming, Douglas W.

1999-01-01

Kinetic stir-flow dissolution experiments were performed on iron- (Fe-SHA), manganese- (Mn-SHA), and copper- (Cu-SHA) containing synthetic hydroxyapatites. Solution treatments consisted of de-ionized water, citric acid and DTPA. Initially, Mn concentrations were higher than Cu concentrations and Fe concentrations were the lowest in all treatments. At later times Mn and Cu concentrations dropped in the DTPA treatment while Fe rose to the concentration similar to Mn and Cu. At all times, metal release concentrations in the water and citric acid treatments followed the trend of Mn>Cu>Fe. Rietveld analysis of x-ray diffraction data and ^31P NMR indicated that the metals substituted for Ca in the SHA structure. However, EPR data suggested that a metal (hydr)oxide phase existed either on the SHA surface or between the SHA crystallites. The metal concentration trend of Mn>Cu>Fe suggested that the initial solution metal concentrations are dependent on the dissolution of (hydr)oxides from SHA surfaces or between SHA crystallites. Similar metal concentrations at later times in the DTPA experiments suggests that metal concentrations were controlled by the release of Mn, Cu, or Fe from the SHA structure.

High sensitive detection of copper II ions using D-penicillamine-coated gold nanorods based on localized surface plasmon resonance.

PubMed

Hong, Yoochan; Jo, Seongjae; Park, Joohyung; Park, Jinsung; Yang, Jaemoon

2018-05-25

In this paper, we describe the development of a nanoplasmonic biosensor based on the localized surface plasmon resonance (LSPR) effect that enables a sensitive and selective recognition of copper II ions. First, we fabricated the nanoplasmonics as LSPR substrates using gold nanorods (GNR) and the nano-adsorption method. The LSPR sensitivity of the nanoplasmonics was evaluated using various solvents with different refractive indexes. Subsequently, D-penicillamine (DPA)-a chelating agent of copper II ions-was conjugated to the surface of the GNR. The limit of detection (LOD) for the DPA-conjugated nanoplasmonics was 100 pM. Furthermore, selectivity tests were conducted using various divalent cations, and sensitivity tests were conducted on the nanoplasmonics under blood-like environments. Finally, the developed nanoplasmonic biosensor based on GNR shows great potential for the effective recognition of copper II ions, even in human blood conditions.

Ion release and cytotoxicity of stainless steel wires.

PubMed

Oh, Keun-Taek; Kim, Kyoung-Nam

2005-12-01

Heat treatment is generally applied to orthodontic stainless steel (SS) wires to relieve the stresses that result from their manipulation by orthodontists. The quality and thickness of the oxide films formed on the surface of heat-treated wires can vary, and it is believed that these oxide films can influence the properties of heat-treated wires. The aim of this study was to investigate the influence of heat treatment and cooling methods on the amount of metal ions released and to examine the cytotoxicity of heat-treated wires. In this study, four types of SS wires (Remanium, Permachrome, Colboloy and Orthos) with a cross-sectional area of 0.41 x 0.56 mm were investigated. These wires were heat-treated in a vacuum, air, or argon environment, and were cooled in either a furnace or a water bath. Four control groups and 24 experimental groups were classified according to the type of wires, heat treatment conditions and cooling methods. In each group, the amount of nickel released as well as its cytotoxicity was investigated. The concentration of dissolved nickel ions in artificial saliva was measured for a period of up to 12 weeks. In all groups, the concentration of dissolved nickel ions in artificial saliva was lowest for the vacuum heat treatment-furnace cooling group and a significant difference was shown compared with the other experimental groups. The concentration of dissolved nickel ions in artificial saliva was highest in the groups heat-treated in air (P < 0.05), while the amount of nickel released was highest in the Remanium and Colboloy (P < 0.05). The cytotoxicity was mild in all the experimental groups but the response index of the air groups was slightly higher than in the other groups. According to these results, SS wires retain their high corrosion resistance and low ion release rate when heat-treated in a vacuum and cooled in a furnace.

Redox Sorption of Oxygen Dissolved in Water on Copper Nanoparticles in an Ion Exchange Matrix

NASA Astrophysics Data System (ADS)

Vakhnin, D. D.; Pridorogina, V. E.; Polyanskii, L. N.; Kravchenko, T. A.; Gorshkov, V. S.

2018-01-01

The redox sorption of molecular oxygen from water by a thin granular layer of a copper-ion exchanger nanocomposite in the currentless mode and under cathodic polarization is studied. The speed of propagation of the boundaries of the chemical reaction of stepwise oxidation of copper nanoparticles under the conditions of polarization slows considerably. At the same time, the amount of electrochemically regenerated copper from the resulting oxides that is capable of interacting with oxygen again grows. The stationarity of the redox sorption of oxygen is due to the equality of the rates of oxidation and reduction of the metallic component of the composite.

Cytotoxicity and genotoxicity of nano - and microparticulate copper oxide: role of solubility and intracellular bioavailability.

PubMed

Semisch, Annetta; Ohle, Julia; Witt, Barbara; Hartwig, Andrea

2014-02-13

Nano- or microscale copper oxide particles (CuO NP, CuO MP) are increasingly applied as catalysts or antimicrobial additives. This increases the risk of adverse health effects, since copper ions are cytotoxic under overload conditions. The extra- and intracellular bioavailability of CuO NP and CuO MP were explored. In addition, different endpoints related to cytotoxicity as well as direct and indirect genotoxicity of the copper oxides and copper chloride (CuCl2) were compared. Comprehensively characterized CuO NP and CuO MP were analysed regarding their copper ion release in model fluids. In all media investigated, CuO NP released far more copper ions than CuO MP, with most pronounced dissolution in artificial lysosomal fluid. CuO NP and CuCl2 caused a pronounced and dose dependent decrease of colony forming ability (CFA) in A549 and HeLa S3 cells, whereas CuO MP exerted no cytotoxicity at concentrations up to 50 μg/mL. Cell death induced by CuO NP was at least in part due to apoptosis, as determined by subdiploid DNA as well as via translocation of the apoptosis inducing factor (AIF) into the cell nucleus. Similarly, only CuO NP induced significant amounts of DNA strand breaks in HeLa S3 cells, whereas all three compounds elevated the level of H2O2-induced DNA strand breaks. Finally, all copper compounds diminished the H2O2-induced poly(ADP-ribosyl)ation, catalysed predominantly by poly(ADP-ribose)polymerase-1 (PARP-1); here, again, CuO NP exerted the strongest effect. Copper derived from CuO NP, CuO MP and CuCl2 accumulated in the soluble cytoplasmic and nuclear fractions of A549 cells, yielding similar concentrations in the cytoplasm but highest concentrations in the nucleus in case of CuO NP. The results support the high cytotoxicity of CuO NP and CuCl2 and the missing cytotoxicity of CuO MP under the conditions applied. For these differences in cytotoxicity, extracellular copper ion levels due to dissolution of particles as well as differences in

Cytotoxicity and genotoxicity of nano - and microparticulate copper oxide: role of solubility and intracellular bioavailability

PubMed Central

2014-01-01

Background Nano- or microscale copper oxide particles (CuO NP, CuO MP) are increasingly applied as catalysts or antimicrobial additives. This increases the risk of adverse health effects, since copper ions are cytotoxic under overload conditions. Methods The extra- and intracellular bioavailability of CuO NP and CuO MP were explored. In addition, different endpoints related to cytotoxicity as well as direct and indirect genotoxicity of the copper oxides and copper chloride (CuCl2) were compared. Results Comprehensively characterized CuO NP and CuO MP were analysed regarding their copper ion release in model fluids. In all media investigated, CuO NP released far more copper ions than CuO MP, with most pronounced dissolution in artificial lysosomal fluid. CuO NP and CuCl2 caused a pronounced and dose dependent decrease of colony forming ability (CFA) in A549 and HeLa S3 cells, whereas CuO MP exerted no cytotoxicity at concentrations up to 50 μg/mL. Cell death induced by CuO NP was at least in part due to apoptosis, as determined by subdiploid DNA as well as via translocation of the apoptosis inducing factor (AIF) into the cell nucleus. Similarly, only CuO NP induced significant amounts of DNA strand breaks in HeLa S3 cells, whereas all three compounds elevated the level of H2O2-induced DNA strand breaks. Finally, all copper compounds diminished the H2O2-induced poly(ADP-ribosyl)ation, catalysed predominantly by poly(ADP-ribose)polymerase-1 (PARP-1); here, again, CuO NP exerted the strongest effect. Copper derived from CuO NP, CuO MP and CuCl2 accumulated in the soluble cytoplasmic and nuclear fractions of A549 cells, yielding similar concentrations in the cytoplasm but highest concentrations in the nucleus in case of CuO NP. Conclusions The results support the high cytotoxicity of CuO NP and CuCl2 and the missing cytotoxicity of CuO MP under the conditions applied. For these differences in cytotoxicity, extracellular copper ion levels due to dissolution of

Biological and Environmental Transformations of Copper-Based Nanomaterials

PubMed Central

Wang, Zhongying; Von Dem Bussche, Annette; Kabadi, Pranita K.; Kane, Agnes B.; Hurt, Robert H.

2013-01-01

Copper-based nanoparticles are an important class of materials with applications as catalysts, conductive inks, and antimicrobial agents. Environmental and safety issues are particularly important for copper-based nanomaterials because of their potential large-scale use and their high redox activity and toxicity reported from in vitro studies. Elemental nanocopper oxidizes readily upon atmospheric exposure during storage and use, so copper oxides are highly relevant phases to consider in studies of environmental and health impacts. Here we show that copper oxide nanoparticles undergo profound chemical transformations under conditions relevant to living systems and the natural environment. Copper oxide nanoparticle (CuO-NP) dissolution occurs at lysosomal pH (4-5), but not at neutral pH in pure water. Despite the near-neutral pH of cell culture medium, CuO-NPs undergo significant dissolution in media over time scales relevant to toxicity testing due to ligand-assisted ion release, in which amino acid complexation is an important contributor. Electron paramagnetic resonance (EPR) spectroscopy shows that dissolved copper in association with CuO-NPs are the primary redox-active species. CuO-NPs also undergo sulfidation by a dissolution-reprecipitation mechanism, and the new sulfide surfaces act as catalysts for sulfide oxidation. Copper sulfide NPs are found to be much less cytotoxic than CuO NPs, which is consistent with the very low solubility of CuS. Despite this low solubility of CuS, EPR studies show that sulfidated CuO continues to generate some ROS activity due to the release of free copper by H2O2 oxidation during the Fenton-chemistry-based EPR assay. While sulfidation can serve as a natural detoxification process for nanosilver and other chalcophile metals, our results suggest that sulfidation may not fully and permanently detoxify copper in biological or environmental compartments that contain reactive oxygen species. PMID:24032665

Comparative contraceptive effectiveness of levonorgestrel-releasing and copper intrauterine devices: the European Active Surveillance Study for Intrauterine Devices.

PubMed

Heinemann, Klaas; Reed, Suzanne; Moehner, Sabine; Minh, Thai Do

2015-04-01

The objective was to measure the rate of unintended pregnancies in women using levonorgestrel-releasing intrauterine systems (LNG IUSs, releasing 20 mcg LNG daily) and copper intrauterine devices (IUDs) in a typical population of IUD users and to describe associated complications. A multinational, prospective, non-interventional cohort study of new users of LNG IUS and copper IUDs was performed. Following a baseline survey, study participants and their physicians completed one follow-up questionnaire after 12 months. A multifaceted four-level follow-up procedure minimized loss to follow-up. Patient-reported outcomes were validated by the treating physicians. A total of 61,448 women with a newly inserted IUD were enrolled in six European countries between 2006 and 2012. The copper IUD cohort contained more than 30 different types. Validated 1-year follow-up information for 58,324 users between 18 and 50 years of age (70% using LNG IUS, 30% using copper IUDs) was collected. A total of 118 contraceptive failures occurred (26 LNG, 92 copper). Both types of IUD were highly effective, with overall Pearl indices of 0.06 [95% confidence interval (CI): 0.04-0.09] and 0.52 (95% CI: 0.42-0.64) for LNG IUS and copper IUDs, respectively. The adjusted hazard ratio for LNG IUS vs. copper IUDs was 0.16 (95% CI: 0.10-0.25). Tenty-one pregnancies (7 LNG IUS, 14 copper IUD) were ectopic, yielding an adjusted hazard ratio for ectopic pregnancy of 0.26 (95% CI: 0.10-0.66). The contraceptive failure rate was low with both IUDs. However, the LNG IUS was associated with a significantly lower risk of pregnancy, including ectopic pregnancy, than the copper IUDs. To our knowledge, this is the first large-scale, multinational, prospective epidemiological study to measure and compare the contraceptive effectiveness of LNG IUSs and copper IUDs during routine clinical practice. Clinicians and patients should be aware of differences in rates of unintended pregnancies and associated complications

Effect of sliding velocity on the tribological behavior of copper and associated nanostructure development

NASA Astrophysics Data System (ADS)

Emge, Andrew

The unlubricated sliding of metals is important in many mechanical devices covering a wide range of sliding velocities. However, the effect of sliding velocity on the tribological behavior of unlubricated metals has not been widely studied. Similarly, the relationship between microstructures developed at high sliding velocities and tribological behavior has not been studied in depth. Microstructures produced at low sliding velocities have been studied extensively and commonly include nanocrystalline or fine grained material near the sliding surface with heavily deformed microstructures further from the surface. The current research relates two aspects of the sliding friction of ductile metals, the effect of sliding velocity and the production of nanocrystalline tribomaterial. The project focused on the effects of sliding velocity on the frictional behavior of oxygen free high conductivity (OFHC) copper sliding against 440C stainless steel, Nitronic 40 stainless steel, and copper. Low velocity tests were performed with a pin on disk tribometer. High velocity tests were performed with a rotating barrel gas gun (RBGG) which combined impact with sliding. The RBGG provides sliding velocities as high as 5.5 m/s and impact velocities as high as 12 m/s while maintaining sliding times on the order of tens of microseconds. Changes in the coefficient of friction, microstructure, and composition were studied. Surface and subsurface microstructures of the worn samples were characterized with a range of instruments including scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), focused ion beam (FIB) milling and imaging, transmission electron microscopy (TEM) with EDS, orientation imaging microscopy (OIM), and nanoindentation. In the case of self-mated copper the sliding velocity had little effect on the coefficient of friction for both experimental apparatuses. For the case of copper sliding against 440C stainless steel on the pin on disk system

Copper stimulation of LHRH release from median eminence explants. III. A process dependent on extracellular sodium.

PubMed

Colombani-Vidal, M; Barnea, A

1986-01-01

Copper, complexed to histidine (CuHis), stimulates LHRH release from explants of the median eminence area (MEA). To gain further understanding of the mechanism of copper action, in this study, we assessed the Na+ and energy requirements for CuHis stimulation of LHRH release. MEA explants, obtained from adult male rats, were incubated at 37 degrees C for 15 min with 100 microM CuHis and then for 45 min in CuHis-free medium (Krebs-Ringer-phosphate buffer, pH 7.4). LHRH released into the medium was evaluated by RIA. When the incubation buffer contained 143 mM Na+, CuHis stimulated the release of LHRH from a basal level of 17.2 +/- 1.26 (mean +/- SEM, n = 7) to 74.5 +/- 6.2 pg/60 min per MEA. When [Na+] was reduced to 16 mM Na+ (by substituting with Li+), CuHis-stimulated LHRH release was inhibited by 80% (p less than 0.001); indicating a requirement for Na+. In addition, we found that CuHis-stimulated LHRH release was a saturable function of Na+ concentration; saturation achieved with about 100 mM Na+. To assess the requirement for Na+ transport, we evaluated the effect of 1 mM ouabain, 10 microM tetrodotoxin (TTX), or 100 microM amiloride on CuHis stimulation of LHRH release. Ouabain inhibited CuHis stimulation of LHRH release by 80%, whereas TTX and amiloride were ineffective. In addition, we observed that CuHis did not stimulate LHRH release when incubation was carried out at 4 degrees C or at 37 degrees C in the presence of 5 mM KCN.(ABSTRACT TRUNCATED AT 250 WORDS)

Storm water runoff measurements of copper from a naturally patinated roof and from a parking space. Aspects on environmental fate and chemical speciation.

PubMed

Odnevall Wallinder, I; Hedberg, Y; Dromberg, P

2009-12-01

Release of copper from a naturally aged copper roof on a shopping centre building in a suburban site of Stockholm has been measured during different rain events after its interaction with the internal drainage system and storm drains made of cast iron and concrete. Concentrations of copper removed by means of urban storm water from a nearby parking space have been determined for comparison. Predictions and measurements of the chemical speciation of released copper are discussed compared to the total concentration, and to threshold values for freshwater and drinking water. The results clearly illustrate that the major part of the released copper from the roof is readily retained already during transport through the internal drainage system of the building, a pathway that also changes the chemical speciation of released copper and its bioavailable fraction. Most copper, not retained by cast iron and concrete surfaces, was strongly complexed to organic matter. The median concentration of free cupric ions and weak copper complexes was less than, or within the range of reported no effect concentrations, NOECs, of copper in surface waters. The parking space contributed with significantly higher and time-dependent concentrations of total copper compared to measured concentrations of copper from the roof after the interaction with the drainage system. Most copper in the surface runoff water was strongly complexed with organic matter, hence reducing the bioavailable fraction significantly to concentrations within the NOEC range. Dilution with other sources of urban storm water will reduce the released concentration of copper even further. The results illustrate that already the internal drainage system and the storm drains made of cast iron and concrete act as efficient sinks for released copper which means that any installation of additional infiltration devices is redundant.

[Effect of Cu2+ and Zn2+ ions in Ca-ATPase activity isolated from Pachymerus nucleorum (Fabricius) (Coleoptera: Chrysomelidae, Bruchinae) larvae].

PubMed

Dias, Decivaldo S; Coelho, Milton V

2007-01-01

ATPases, an important target of insecticides, are enzymes that hydrolyze ATP and use the energy released in that process to accomplish some type of cellular work. Pachymerus nucleorum (Fabricius) larvae possess an ATPase, that presents high Ca-ATPase activity, but no Mg-ATPase activity. In the present study, the effect of zinc and copper ions in the activity Ca-ATPase of that enzyme was tested. More than 90% of the Ca-ATPase activity was inhibited in 0.5 mM of copper ions or 0.25 mM of zinc ions. In the presence of EDTA, but not in the absence, the inhibition by zinc was reverted with the increase of calcium concentration. The inhibition by copper ions was not reverted in the presence or absence of EDTA. The Ca-ATPase was not inhibited by treatment of the ATPase fraction with copper, suggesting that the copper ion does not bind directly to the enzyme. The results suggest that zinc and copper ions form a complex with ATP and bind to the enzyme inhibiting its Ca-ATPase activity.

Porins Increase Copper Susceptibility of Mycobacterium tuberculosis

PubMed Central

Speer, Alexander; Rowland, Jennifer L.; Haeili, Mehri; Niederweis, Michael

2013-01-01

Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increases tolerance for copper at elevated concentrations, indicating that porins mediate copper uptake across the outer membrane. Heterologous expression of the mycobacterial porin gene mspA reduced growth of M. tuberculosis in the presence of 2.5 μM copper by 40% and completely suppressed growth at 15 μM copper, while wild-type M. tuberculosis reached its normal cell density at that copper concentration. Moreover, the polyamine spermine, a known inhibitor of porin activity in Gram-negative bacteria, enhanced tolerance of M. tuberculosis for copper, suggesting that copper ions utilize endogenous outer membrane channel proteins of M. tuberculosis to gain access to interior cellular compartments. In summary, these findings highlight the outer membrane as the first barrier against copper ions and the role of porins in mediating copper uptake in M. smegmatis and M. tuberculosis. PMID:24013632

Three-dimensional, two-species magnetohydrodynamic studies of the early time behaviors of the Combined Release and Radiation Effects Satellite G2 barium release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Lianghai, E-mail: xielh@nssc.ac.cn; Li, Lei; Wang, Jingdong

2014-04-15

We present a three-dimensional, two-species (Ba{sup +} and H{sup +}) MHD model to study the early time behaviors of a barium release at about 1 R{sub E} like Combined Release and Radiation Effects Satellite G2, with emphasis placed on the three-dimensional evolution of the barium cloud and its effects on the ambient plasma environment. We find that the perturbations caused by the cloud are the combined results of the initial injection, the radial expansion, and the diamagnetic effect and propagate as fast MHD waves in the magnetosphere. In return, the transverse expansion and the cross-B motion of barium ions aremore » constrained by the magnetic force, which lead to a field-aligned striation of ions and the decoupling of these ions from the neutrals. Our simulation shows the formation and collapse of the diamagnetic cavity in the barium cloud. The estimated time scale for the cavity evolution might be much shorter if photoionization time scale and field aligned expansion of barium ions are considered. In addition, our two species MHD simulation also finds the snowplow effect resulting from the momentum coupling between barium ions and background H{sup +}, which creates density hole and bumps in the background H{sup +} when barium ions expanding along the magnetic field lines.« less

Development and tests of molybdenum armored copper components for MITICA ion source

NASA Astrophysics Data System (ADS)

Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

2016-02-01

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

Development and tests of molybdenum armored copper components for MITICA ion source.

PubMed

Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

2016-02-01

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

Nanoscale Zero-Valent Iron Decorated on Bentonite/Graphene Oxide for Removal of Copper Ions from Aqueous Solution.

PubMed

Shao, Jicheng; Yu, Xiaoniu; Zhou, Min; Cai, Xiaoqing; Yu, Chuang

2018-06-04

The removal efficiency of Cu(II) in aqueous solution by bentonite, graphene oxide (GO), and nanoscale iron decorated on bentonite (B-nZVI) and nanoscale iron decorated on bentonite/graphene oxide (GO-B-nZVI) was investigated. The results indicated that GO-B-nZVI had the best removal efficiency in different experimental environments (with time, pH, concentration of copper ions, and temperature). For 16 hours, the removal efficiency of copper ions was 82% in GO-B-nZVI, however, it was 71% in B-nZVI, 26% in bentonite, and 18% in GO. Bentonite, GO, B-nZVI, and GO-B-nZVI showed an increased removal efficiency of copper ions with the increase of pH under a certain pH range. The removal efficiency of copper ions by GO-B-nZVI first increased and then fluctuated slightly with the increase of temperature, while B-nZVI and bentonite increased and GO decreased slightly with the increase of temperature. Lorentz-Transmission Electron Microscope (TEM) images showed the nZVI particles of GO-B-nZVI dispersed evenly with diameters ranging from 10 to 86.93 nm. Scanning electron microscope (SEM) images indicated that the nanoscale iron particles were dispersed evenly on bentonite and GO with no obvious agglomeration. The q e,cal (73.37 mg·g -1 and 83.89 mg·g -1 ) was closer to the experimental value q e,exp according to the pseudo-second-order kinetic model. The q m of B-nZVI and GO-B-nZVI were 130.7 mg·g -1 and 184.5 mg·g -1 according to the Langmuir model.

Catalytic therapy of cancer by ascorbic acid involves redox cycling of exogenous/endogenous copper ions and generation of reactive oxygen species.

PubMed

Hadi, S M; Ullah, M F; Shamim, U; Bhatt, S H; Azmi, A S

2010-01-01

Catalytic therapy is a cancer treatment modality based on the generation of reactive oxygen species (ROS) through administration of ascorbate/medicinal herbal extracts and copper. It is known that antioxidants such as ascorbate also exhibit prooxidant activity in the presence of transition metals such as copper. Based on our work and that in the literature, in this review we propose a mechanism for the cytotoxic action of ascorbate against cancer cells. It involves redox cycling of exogenous/endogenous copper ions and the consequent generation of ROS leading to oxidative DNA breakage. Using human peripheral lymphocytes and the Comet assay, we have shown that ascorbic acid is able to cause oxidative breakage in cellular DNA. Such DNA degradation is inhibited by neocuproine (a Cu(I) sequestering agent) and scavengers of ROS indicating that the cellular DNA breakage involves the generation of Cu(I) and formation of ROS. Similar results are also obtained with plant polyphenol antioxidants that are important constituents of medicinal herbal extracts. Copper is an essential component of chromatin and can take part in redox reactions. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Therefore, cancer cells may be more subject to electron transfer between copper ions and ascorbate/plant polyphenols to generate ROS. In this review we cite evidence to indicate that in catalytic therapy cytotoxic action against cancer cells involves redox cycling of exogenous/endogenous copper ions. Copyright © 2010 S. Karger AG, Basel.

A cytosolic copper storage protein provides a second level of copper tolerance in Streptomyces lividans.

PubMed

Straw, Megan L; Chaplin, Amanda K; Hough, Michael A; Paps, Jordi; Bavro, Vassiliy N; Wilson, Michael T; Vijgenboom, Erik; Worrall, Jonathan A R

2018-01-24

Streptomyces lividans has a distinct dependence on the bioavailability of copper for its morphological development. A cytosolic copper resistance system is operative in S. lividans that serves to preclude deleterious copper levels. This system comprises of several CopZ-like copper chaperones and P 1 -type ATPases, predominantly under the transcriptional control of a metalloregulator from the copper sensitive operon repressor (CsoR) family. In the present study, we discover a new layer of cytosolic copper resistance in S. lividans that involves a protein belonging to the newly discovered family of copper storage proteins, which we have named Ccsp (cytosolic copper storage protein). From an evolutionary perspective, we find Ccsp homologues to be widespread in Bacteria and extend through into Archaea and Eukaryota. Under copper stress Ccsp is upregulated and consists of a homotetramer assembly capable of binding up to 80 cuprous ions (20 per protomer). X-ray crystallography reveals 18 cysteines, 3 histidines and 1 aspartate are involved in cuprous ion coordination. Loading of cuprous ions to Ccsp is a cooperative process with a Hill coefficient of 1.9 and a CopZ-like copper chaperone can transfer copper to Ccsp. A Δccsp mutant strain indicates that Ccsp is not required under initial copper stress in S. lividans, but as the CsoR/CopZ/ATPase efflux system becomes saturated, Ccsp facilitates a second level of copper tolerance.

Excitation functions of heavy ion induced nuclear reactions between 16O ion beam and natural copper: Measurements, analysis and its applicability in TLA study

NASA Astrophysics Data System (ADS)

Chowdhury, D. P.; Guin, R.; Saha, S. K.; Sudersanan, M.

2003-11-01

Experimental cross sections of a number of reaction channels of 16O ion induced reactions on natural copper target have been determined at different energies in the range of 50-110 MeV of 16O projectile by stacked foil activation technique. The cross sections have been compared with theoretical calculations using the computer code ALICE-91. The experimental values compared reasonably well with the corresponding theoretical estimates. The results indicate no significant role of incomplete fusion process in the 16O induced reactions on natural copper in the energy range of ⩽7 MeV/nucleon. As heavy ion beam produces an extremely narrow layer of activities in the surface of a material, these reactions could be useful for thin layer activation (TLA) study. The purpose of this work is to apply heavy ion activation in TLA technique for the study of surface wear with increased sensitivity.

The effects of silver ions on copper metabolism in rats.

PubMed

Ilyechova, E Yu; Saveliev, A N; Skvortsov, A N; Babich, P S; Zatulovskaia, Yu A; Pliss, M G; Korzhevskii, D E; Tsymbalenko, N V; Puchkova, L V

2014-10-01

The influence of short and prolonged diet containing silver ions (Ag-diet) on copper metabolism was studied. Two groups of animals were used: one group of adult rats received a Ag-diet for one month (Ag-A1) and another group received a Ag-diet for 6 months from birth (Ag-N6). In Ag-A1 rats, the Ag-diet caused a dramatic decrease of copper status indexes that was manifested as ceruloplasmin-associated copper deficiency. In Ag-N6 rats, copper status indexes decreased only 2-fold as compared to control rats. In rats of both groups, silver entered the bloodstream and accumulated in the liver. Silver was incorporated into ceruloplasmin (Cp), but not SOD1. In the liver, a prolonged Ag-diet caused a decrease of the expression level of genes, associated with copper metabolism. Comparative spectrophotometric analysis of partially purified Cp fractions has shown that Cp from Ag-N6 rats was closer to holo-Cp by specific enzymatic activities and tertiary structure than Cp from Ag-A1 rats. However, Cp of Ag-N6 differs from control holo-Cp and Cp of Ag-A1 in its affinity to DEAE-Sepharose and in its binding properties to lectins. In the bloodstream of Ag-N6, two Cp forms are present as shown in pulse-experiments on rats with the liver isolated from circulation. One of the Cp isoforms is of hepatic origin, and the other is of extrahepatic origin; the latter is characterized by a faster rate of secretion than hepatic Cp. These data allowed us to suggest that the disturbance of holo-Cp formation in the liver was compensated by induction of extrahepatic Cp synthesis. The possible biological importance of these effects is discussed.

Changes in the structure and wear resistance of the surface layer of copper under treatment by nitrogen ion beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sergeev, Victor P., E-mail: vserg@mail.tomsknet.ru, E-mail: kmp1980@mail.ru; Kalashnikov, Mark P., E-mail: vserg@mail.tomsknet.ru, E-mail: kmp1980@mail.ru; Rybalko, Evgeniya V., E-mail: evgeniaribka@yandex.com, E-mail: alfred-1972@mail.ru, E-mail: tehnovak@ispms.tsc.ru, E-mail: zhastas@mail.ru

2014-11-14

The structural-phase state of the treated sample surface was investigated by TEM. It was shown by the TEM and VIMS method that the improvement of tribological properties of the copper samples can be associated with an increase of relaxation ability due to a significant increase of the nitrogen concentration in it, which is accompanied by the refinement of fcc-Cu main phase grain structure and the formation of nanopores or gas bubbles in the ion-modified surface layer. A high-dose implantation of nitrogen ions and copper samples increases the wear resistance in 1.5-4.5 times together with a counterbody from the same materialmore » in the argon environment. The microhardness of the copper samples also increases.« less

Immobilization of Magnetic Nanoparticles onto Amine-Modified Nano-Silica Gel for Copper Ions Remediation

PubMed Central

Elkady, Marwa; Hassan, Hassan Shokry; Hashim, Aly

2016-01-01

A novel nano-hybrid was synthesized through immobilization of amine-functionalized silica gel nanoparticles with nanomagnetite via a co-precipitation technique. The parameters, such as reagent concentrations, reaction temperature and time, were optimized to accomplish the nano-silica gel chelating matrix. The most proper amine-modified silica gel nanoparticles were immobilized with magnetic nanoparticles. The synthesized magnetic amine nano-silica gel (MANSG) was established and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and vibrating sample magnetometry (VSM). The feasibility of MANSG for copper ions’ remediation from wastewater was examined. MANSG achieves a 98% copper decontamination from polluted water within 90 min. Equilibrium sorption of copper ions onto MANSG nanoparticles obeyed the Langmuir equation compared to the Freundlich, Temkin, Elovich and Dubinin-Radushkevich (D-R) equilibrium isotherm models. The pseudo-second-order rate kinetics is appropriate to describe the copper sorption process onto the fabricated MANSG. PMID:28773583

The interaction of copper ions with Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli: an X-ray absorption near-edge structure (XANES) spectroscopy study.

PubMed

Zanzen, Ulrike; Bovenkamp-Langlois, Lisa; Klysubun, Wantana; Hormes, Josef; Prange, Alexander

2018-04-01

The antimicrobial properties of copper ions have been known for a long time. However, the exact mechanism of action of the transition metal on microorganisms has long been unclear. X-ray absorption near-edge structure (XANES) spectroscopy at the Cu K edge allows the determination of copper speciation in Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa that have been treated with Cu(II) and Cu(I) solutions. The death/inactivation of the bacteria was observed using plate counting and light microscopy. The Cu K-XANES spectra of the two Gram-negative bacteria are different than those of the Gram-positive strain. The results clearly show that the Cu + -S bond contributes to the antibacterial activity of copper, as in the case of silver. The detailed evaluation of the differentiated absorption spectra shows that Cu + (not Cu 2+ ) is the dominant ion that binds to the bacteria. Because Cu + is not the most common copper ion, copper is not as effective an antibacterial agent as silver, whose common valency is actually + 1. Any reaction of copper with phosphorus from the bacteria can be excluded after the evaluation of the absorption spectra.

Background Characterization for Thermal Ion Release Experiments with 224Ra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwong, H.; /Stanford U., Phys. Dept.; Rowson, P.

The Enriched Xenon Observatory for neutrinoless double beta decay uses {sup 136}Ba identification as a means for verifying the decay's occurrence in {sup 136}Xe. A current challenge is the release of Ba ions from the Ba extraction probe, and one possible solution is to heat the probe to high temperatures to release the ions. The investigation of this method requires a characterization of the alpha decay background in our test apparatus, which uses a {sup 228}Th source that produces {sup 224}Ra daughters, the ionization energies of which are similar to those of Ba. For this purpose, we ran a backgroundmore » count with our apparatus maintained at a vacuum, and then three counts with the apparatus filled with Xe gas. We were able to match up our alpha spectrum in vacuum with the known decay scheme of {sup 228}Th, while the spectrum in xenon gas had too many unresolved ambiguities for an accurate characterization. We also found that the alpha decays occurred at a near-zero rate both in vacuum and in xenon gas, which indicates that the rate was determined by {sup 228}Th decays. With these background measurements, we can in the future make a more accurate measurement of the temperature dependency of the ratio of ions to neutral atoms released from the hot surface of the probe, which may lead to a successful method of Ba ion release.« less

High temperature fatigue behavior of tungsten copper composites

NASA Technical Reports Server (NTRS)

Verrilli, Michael J.; Kim, Yong-Suk; Gabb, Timothy P.

1989-01-01

The high temperature fatigue behavior of a 9 vol percent, tungsten fiber reinforced copper matrix composite was investigated. Load-controlled isothermal fatigue experiments at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in phase and out of phase between 260 and 560 C, were performed. The stress-strain response displayed considerable inelasticity under all conditions. Also, strain ratcheting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratcheting was always in a tensile direction, continuing until failure. The ratcheting during the out-of-phase TMF test shifted from a tensile direction to a compressive direction. This behavior was thought to be associated with the observed bulging and the extensive cracking of the out-of-phase specimen. For all cases, the fatigue lives were found to be controlled by damage to the copper matrix. Grain boundary cavitation was the dominant damage mechanism of the matrix. On a stress basis, TMF loading reduced lives substantially, relative to isothermal cycling. In-phase cycling resulted in the shortest lives, and isothermal fatigue at 260 C, the longest.

Copper Corrosion and Biocorrosion Events in Premise Plumbing

PubMed Central

Fischer, Diego A.; Alsina, Marco A.; Pastén, Pablo A.

2017-01-01

Corrosion of copper pipes may release high amounts of copper into the water, exceeding the maximum concentration of copper for drinking water standards. Typically, the events with the highest release of copper into drinking water are related to the presence of biofilms. This article reviews this phenomenon, focusing on copper ingestion and its health impacts, the physicochemical mechanisms and the microbial involvement on copper release, the techniques used to describe and understand this phenomenon, and the hydrodynamic effects. A conceptual model is proposed and the mathematical models are reviewed. PMID:28872628

Copper Corrosion and Biocorrosion Events in Premise Plumbing.

PubMed

Vargas, Ignacio T; Fischer, Diego A; Alsina, Marco A; Pavissich, Juan P; Pastén, Pablo A; Pizarro, Gonzalo E

2017-09-05

Corrosion of copper pipes may release high amounts of copper into the water, exceeding the maximum concentration of copper for drinking water standards. Typically, the events with the highest release of copper into drinking water are related to the presence of biofilms. This article reviews this phenomenon, focusing on copper ingestion and its health impacts, the physicochemical mechanisms and the microbial involvement on copper release, the techniques used to describe and understand this phenomenon, and the hydrodynamic effects. A conceptual model is proposed and the mathematical models are reviewed.

Morphology of gold and copper ion-plated coatings

NASA Technical Reports Server (NTRS)

Spalvins, T.

1978-01-01

Copper and gold films (0.2 to 2 microns thick) were ion plated onto polished 304-stainless-steel, glass, mica surfaces. These coatings were examined by SEM for defects in their morphological growth. Three types of defects were distinguished: nodular growth, abnormal or runaway growth, and spits. The cause for each type of defect was investigated. Nodular growth is due to inherent substrate microdefects, abnormal or runaway growth is due to external surface inclusions, and spits are due to nonuniform evaporation (ejection of droplets). All these defects induce stresses and produce porosity in the coatings and thus weaken their mechanical properties. During surface rubbing, large nodules are pulled out, leaving vacancies in the coatings.

The effect of copper on eumelanin photophysics and morphology

NASA Astrophysics Data System (ADS)

Birch, David J. S.; Sutter, Jens U.

2013-02-01

Despite being an important pigment in skin, hair, the eye and the brain, melanin remains one of the most enigmatic of pigments. Although the main constituents of melanin are known to be dihydroxyindoles, its photophysics is complex and its detailed structure remains unknown. In this work we have arrested prior to completion the usual synthesis of eumelanin formed via auto-oxidation of 3, 4-dihydroxy-L-phenylalanine (L-DOPA), by the addition of copper ions. Using fluorescence techniques we report how copper modifies the self assembly of eumelanin by reducing the time to the onset of aggregation at pH 10 and yet produces simplified photophysics in terms of a clearly-defined fluorescence spectrum and a fluorescence decay that is described well by a dominant single lifetime of ~ 6ns. This behavior is consistent with copper inducing an enhanced abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). Metal ion binding to melanin is of particular importance to neurology and has potential applications in optoelectronics.

Development and tests of molybdenum armored copper components for MITICA ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavei, Mauro, E-mail: mauro.pavei@igi.cnr.it; Marcuzzi, Diego; Rizzolo, Andrea

2016-02-15

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analysesmore » of the prototypes simulating the test conditions in GLADIS as well as the experimental results.« less

Evaluation of ion release, cytotoxicity, and platelet adhesion of electrochemical anodized 316 L stainless steel cardiovascular stents.

PubMed

Díaz, M; Sevilla, P; Galán, A M; Escolar, G; Engel, E; Gil, F J

2008-11-01

316L Stainless steel is one of the most used metallic material in orthopedical prosthesis, osteosinthesis plates, and cardiovascular stents. One of the main problems this material presents is the nickel and chromium release, specially the Ni ion release that provokes allergy in a high number of patients. Recently, experimental applications in vitro and in vivo seem to indicate that the thickness of the nature oxide of the stainless steel results in very strong reinforcement of the biological response and reduce the ion release due to the thicker surface oxide. It is possible to grow the natural chromium oxide layer by electrolytic method such anodization. In this study, two main anodization methods to grow chromium oxide on the 316L stainless steel have been evaluated. Nickel and Chromium ions release in human blood at 37 degrees C were detected at times of 1, 6, 11, and 15 days by means of atomic absorption in a graphite furnace (GAAF). Moreover, cytocompatibility tests were carried out. Perfusion experiments were performed to evaluate morphometrically platelet interaction with the material and to explore the potential thrombogenicity. The results showed a good cytocompatibility between the material and the osteoblast-like cells. However, these anodization methods released between 2 and 10 times more nickel and chromium than the original stainless steel, depending on the method used. Besides, anodized samples shown an increase of the percentage of surface covered by platelets. Consequently, the anodization methods studied do not improve the long-term behavior of the stainless steel for its application as cardiovascular stents.

Advantages and challenges of increased antimicrobial copper use and copper mining.

PubMed

Elguindi, Jutta; Hao, Xiuli; Lin, Yanbing; Alwathnani, Hend A; Wei, Gehong; Rensing, Christopher

2011-07-01

Copper is a highly utilized metal for electrical, automotive, household objects, and more recently as an effective antimicrobial surface. Copper-containing solutions applied to fruits and vegetables can prevent bacterial and fungal infections. Bacteria, such as Salmonellae and Cronobacter sakazakii, often found in food contamination, are rapidly killed on contact with copper alloys. The antimicrobial effectiveness of copper alloys in the healthcare environment against bacteria causing hospital-acquired infections such as methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli O157:H7, and Clostridium difficile has been described recently. The use of copper and copper-containing materials will continue to expand and may lead to an increase in copper mining and production. However, the copper mining and manufacturing industry and the consumer do not necessarily enjoy a favorable relationship. Open pit mining, copper mine tailings, leaching products, and deposits of toxic metals in the environment often raises concerns and sometimes public outrage. In addition, consumers may fear that copper alloys utilized as antimicrobial surfaces in food production will lead to copper toxicity in humans. Therefore, there is a need to mitigate some of the negative effects of increased copper use and copper mining. More thermo-tolerant, copper ion-resistant microorganisms could improve copper leaching and lessen copper groundwater contamination. Copper ion-resistant bacteria associated with plants might be useful in biostabilization and phytoremediation of copper-contaminated environments. In this review, recent progress in microbiological and biotechnological aspects of microorganisms in contact with copper will be presented and discussed, exploring their role in the improvement for the industries involved as well as providing better environmental outcomes.

Influences of Au ion radiation on microstructure and surface-enhanced Raman scattering of nanoporous copper

NASA Astrophysics Data System (ADS)

Wang, Jing; Hu, Zhaoyi; Li, Rui; Liu, Xiongjun; Xu, Chuan; Wang, Hui; Wu, Yuan; Fu, Engang; Lu, Zhaoping

2018-05-01

In this work, effects of Au ion irradiation on microstructure and surface-enhanced Raman scattering (SERS) performance of nanoporous copper (NPC) were investigated. It is found that the microstructure of NPC could be tailored by the ion irradiation dose, i.e., the pore size decreases while the ligament size significantly coarsens with the increase of the irradiation dose. In addition, the SERS enhancement for rhodamine 6G molecules was improved by Au ions irradiation at an appropriate dose. The underlying mechanism of the increase of SERS enhancement resulted from ion irradiation was discussed. Our findings could provide a new way to tune nanoporosity of nanoporous metals and improve their SERS performance.

Influences of Au ion radiation on microstructure and surface-enhanced Raman scattering of nanoporous copper.

PubMed

Wang, Jing; Hu, Zhaoyi; Li, Rui; Liu, Xiongjun; Xu, Chuan; Wang, Hui; Wu, Yuan; Fu, Engang; Lu, Zhaoping

2018-05-04

In this work, effects of Au ion irradiation on microstructure and surface-enhanced Raman scattering (SERS) performance of nanoporous copper (NPC) were investigated. It is found that the microstructure of NPC could be tailored by the ion irradiation dose, i.e., the pore size decreases while the ligament size significantly coarsens with the increase of the irradiation dose. In addition, the SERS enhancement for rhodamine 6G molecules was improved by Au ions irradiation at an appropriate dose. The underlying mechanism of the increase of SERS enhancement resulted from ion irradiation was discussed. Our findings could provide a new way to tune nanoporosity of nanoporous metals and improve their SERS performance.

A ligation DNAzyme-induced magnetic nanoparticles assembly for ultrasensitive detection of copper ions.

PubMed

Yin, Honghong; Kuang, Hua; Liu, Liqiang; Xu, Liguang; Ma, Wei; Wang, Libing; Xu, Chuanlai

2014-04-09

A novel biosensor for ultrasensitive detection of copper (Cu(2+)) was established based on the assembly of magnetic nanoparticles induced by the Cu(2+)-dependent ligation DNAzyme. With a low limit of detection of 2.8 nM and high specificity, this method has the potential to serve as a general platform for the detection of heavy metal ions.

A novel high performance nano chemosensor for copper (II) ion based on an ultrasound-assisted synthesized diphenylamine-based Schiff base: Design, fabrication and density functional theory calculations.

PubMed

Parsaee, Zohreh; Haratipour, Pouya; Lariche, Milad Janghorban; Vojood, Arash

2018-03-01

A novel high selective colorimetric chemosensor was introduced based on a nano diphenyl-based Schiff base (H 2 L), 2,2'-((1E,1'E)-(((hexylazanediyl)bis(4,1-phenylene))bis(methanylylidene))bis(azanylylidene))bis(4-methylphenol) that synthesized using sonochemical method. H 2 L was characterized by FT-IR, MS, TGA, 1 H NMR, 13 C NMR, SEM and elemental analysis techniques, then fabricated as the portable strips for sensing copper (II) ions in aqueous media. The binding interaction between H 2 L and various metal ions was investigated by UV-Vis spectroscopic that showed favorable coordination toward Cu 2+ ion. H 2 L exhibited binding-induced color changes from yellow to pink and practically no interference in the presence of other metal ions, i.e., Cr 2+ , Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Hg 2+ , Pb 2+ , Mg 2+ and Ca 2+ . The chemsensor showd the color change from yellow to pink in presence of copper (II) ion in aqueous media due to binging of H 2 L and Cu (II). This sensor can determine the copper (II) at in the rang of 7.5 × 10 -8 -1.8 × 10 -5  mol L -1 with a correlation equation: Absorbance = 0.0450[Cu 2+ ] × 10 -6  + 0.71 and R 2  = 0.975 and low detection limit of 1.89 × 10 -8  mol L -1 . Density functional theory (DFT) calculations were carried out at the B3LYP levels of theory with B3LYP/6-311+G(d,p) and LANL2DZ/6-311+G(d,p) basis sets for chemosensor and its copper complex respectively. The optimized geometry, harmonic vibrational frequencies, 1 H NMR and 13 C NMR chemical, Molecular orbital (M.O.), Mulliken population analysis (MPA), contour of Electrostatic Potential (ESP) and Molecular Electrostatic Potential (MEP) map of H 2 L were calculated which show good agreement with behavior of sensor for detection of Cu 2+ ion. Copyright © 2017 Elsevier B.V. All rights reserved.

Nickel and chromium ion release from stainless steel bracket on immersion various types of mouthwashes

NASA Astrophysics Data System (ADS)

Mihardjanti, M.; Ismah, N.; Purwanegara, M. K.

2017-08-01

The stainless steel bracket is widely used in orthodontics because of its mechanical properties, strength, and good biocompatibility. However, under certain conditions, it can be susceptible to corrosion. Studies have reported that the release of nickel and chromium ions because of corrosion can cause allergic reactions in some individuals and are mutagenic. The condition of the oral environment can lead to corrosion, and one factor that can alter the oral environment is mouthwash. The aim of this study was to measure the nickel and chromium ions released from stainless steel brackets when immersed in mouthwash and aquadest. The objects consisted of four groups of 17 maxillary premolar brackets with .022 slots. Each group was immersed in a different mouthwash and aquadest and incubated at 37 °C for 30 days. After 30 days of immersion, the released ions were measured using the ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). For statistical analysis, both the Kruskal-Wallis and Mann-Whitney tests were used. The results showed differences among the four groups in the nickel ions released (p < 0.05) and the chromium ions released (p < 0.5). In conclusion, the ions released as a result of mouthwash immersion have a small value that is below the limit of daily intake recommended by the World Health Organization.

Estimating Dermal Transfer of Copper Particles from the ...

EPA Pesticide Factsheets

Lumber pressure-treated with micronized copper was examined for the release of copper and copper micro/nanoparticles using a surface wipe method to simulate dermal transfer. In 2003, the wood industry began replacing CCA treated lumber products for residential use with copper based formulations. Micronized copper (nano to micron sized particles) has become the preferred treatment formulation. There is a lack of information on the release of copper, the fate of the particles during dermal contact, and the copper exposure level to children from hand-to-mouth transfer. For the current study, three treated lumber products, two micronized copper and one ionic copper, were purchased from commercial retailers. The boards were left to weather outdoors for approximately 1 year. Over the year time period, hand wipe samples were collected periodically to determine copper transfer from the wood surfaces. The two micronized formulations and the ionic formulation released similar levels of total copper. The amount of copper released was high initially, but decreased to a constant level (~1.5 mg m-2) after the first month of outdoor exposure. Copper particles were identified on the sampling cloths during the first two months of the experiment, after which the levels of copper were insufficient to collect interpretable data. After 1 month, the particles exhibited minimal changes in shape and size. At the end of 2-months, significant deterioration of the particles was

Programmable Payload Release from Transient Polymer Microcapsules Triggered by a Specific Ion Coactivation Effect.

PubMed

Tang, Shijia; Tang, Liuyan; Lu, Xiaocun; Liu, Huiying; Moore, Jeffrey S

2018-01-10

Stimuli-responsive materials activated by a pair of molecular or ionic species are of interest in the design of chemical logic gates and signal amplification schemes. There are relatively few materials whose coactivated response has been well-characterized. Here, we demonstrate a specific ion coactivation (SICA) effect at the interfaces of transient polymer solids and liquid solutions. We found that depolymerization of the transient polymer, cyclic poly(phthalaldehyde) (cPPA), exhibited a SICA effect when the cPPA core-shell microcapsules were suspended in ion-containing acidic methanol solutions. Significant acceleration in cPPA depolymerization rate is triggered by the combination of acid and ion coactivators. Intriguingly, the SICA effect is related to the Hofmeister behavior. The SICA effect is primarily determined by anions, and cations exhibit a secondary effect that modulates the coactivation strength. Based on these observations, we developed cPPA programmable microcapsules whose payload release rates depend on the composition and concentration of the salt/acidic-methanol solutions.

High sensitive detection of copper II ions using D-penicillamine-coated gold nanorods based on localized surface plasmon resonance

NASA Astrophysics Data System (ADS)

Hong, Yoochan; Jo, Seongjae; Park, Joohyung; Park, Jinsung; Yang, Jaemoon

2018-05-01

In this paper, we describe the development of a nanoplasmonic biosensor based on the localized surface plasmon resonance (LSPR) effect that enables a sensitive and selective recognition of copper II ions. First, we fabricated the nanoplasmonics as LSPR substrates using gold nanorods (GNR) and the nano-adsorption method. The LSPR sensitivity of the nanoplasmonics was evaluated using various solvents with different refractive indexes. Subsequently, D-penicillamine (DPA)—a chelating agent of copper II ions—was conjugated to the surface of the GNR. The limit of detection (LOD) for the DPA-conjugated nanoplasmonics was 100 pM. Furthermore, selectivity tests were conducted using various divalent cations, and sensitivity tests were conducted on the nanoplasmonics under blood-like environments. Finally, the developed nanoplasmonic biosensor based on GNR shows great potential for the effective recognition of copper II ions, even in human blood conditions.

Concentration and form of copper released into aquatic systems from commercial liquid and micronized pressure treated lumber.

EPA Science Inventory

The fate and effects of pristine engineered metal nanomaterials (ENMs) in simplified systems have been widely studied; however, little is known about the potential release and impact of metal ENMs from consumer goods, especially lumber that has been treated with micronized copper...

Flavonoids-induced redox cycling of copper ions leads to generation of reactive oxygen species: A potential role in cancer chemoprevention.

PubMed

Arif, Hussain; Sohail, Aamir; Farhan, Mohd; Rehman, Ahmed Abdur; Ahmad, Aamir; Hadi, S M

2018-01-01

Flavonoids, a class of polyphenols are known to be effective inducers of apoptosis and cytotoxicity in cancer cells. It is believed that antioxidant activity of polyphenols cannot fully account for induction of apoptosis and chemotherapeutic prevention in various cancers. In this article, by employing single cell alkaline gel electrophoresis (comet assay), we established that antioxidants, flavonoids such as (myricetin=MN, fisetin=FN, quercetin=QN, kaempferol=KL and galangin=GN) can cause cellular DNA breakage, also act as pro-oxidant in presence of transition metal ion such as copper. It was observed that the extent of cellular DNA breakage was found significantly higher in presence of copper. Hydroxyl radicals are generated as a sign of flavonoids' pro-oxidant nature through redox recycling of copper ions. Further, a dose-dependent inhibition of proliferation of breast cancer cells MDA-MB-231 by MN was found leading to pro-oxidant cell death, as assessed by MTT assay. Since levels of copper are considerably elevated in tissue, cell and serum during various malignancies, suggesting that cancer cells would be more subject to copper induced oxidative DNA breakage. Such a copper dependent pro-oxidant cytotoxic mechanism better explains the anticancer activity and preferential cytotoxicity of dietary phytochemicals against cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Copper(II) ions and the Alzheimer's amyloid-β peptide: Affinity and stoichiometry of binding

NASA Astrophysics Data System (ADS)

Tõugu, Vello; Friedemann, Merlin; Tiiman, Ann; Palumaa, Peep

2014-10-01

Deposition of amyloid beta (Aβ) peptides into amyloid plaques is the hallmark of Alzheimer's disease. According to the amyloid cascade hypothesis this deposition is an early event and primary cause of the disease, however, the mechanisms that cause this deposition remain elusive. An increasing amount of evidence shows that the interactions of biometals can contribute to the fibrillization and amyloid formation by amyloidogenic peptides. From different anions the copper ions deserve the most attention since it can contribute not only toamyloid formation but also to its toxicity due to the generation of ROS. In this thesis we focus on the affinity and stoichiometry of copper(II) binding to the Aβ molecule.

Release of nickel and chromium ions from orthodontic wires following the use of teeth whitening mouthwashes.

PubMed

Mirhashemi, AmirHossein; Jahangiri, Sahar; Kharrazifard, MohammadJavad

2018-02-05

Corrosion resistance is an important requirement for orthodontic appliances. Nickel and chromium may be released from orthodontic wires and can cause allergic reactions and cytotoxicity when patients use various mouthwashes to whiten their teeth. Our study aimed to assess the release of nickel and chromium ions from nickel titanium (NiTi) and stainless steel (SS) orthodontic wires following the use of four common mouthwashes available on the market. This in vitro, experimental study was conducted on 120 orthodontic appliances for one maxillary quadrant including five brackets, one band and half of the required length of SS, and NiTi wires. The samples were immersed in Oral B, Oral B 3D White Luxe, Listerine, and Listerine Advance White for 1, 6, 24, and 168 h. The samples immersed in distilled water served as the control group. Atomic absorption spectroscopy served to quantify the amount of released ions. Nickel ions were released from both wires at all time-points; the highest amount was in Listerine and the lowest in Oral B mouthwashes. The remaining two solutions were in-between this range. The process of release of chromium from the SS wire was the same as that of nickel. However, the release trend in NiTi wires was not uniform. Listerine caused the highest release of ions. Listerine Advance White, Oral B 3D White Luxe, and distilled water were the same in terms of ion release. Oral B showed the lowest amount of ion release.

Antibacterial activity and ion release of bonding agent containing amorphous calcium phosphate nanoparticles

PubMed Central

Chen, Chen; Weir, Michael D.; Cheng, Lei; Lin, Nancy; Lin-Gibson, Sheng; Chow, Laurence C.; Zhou, Xuedong; Xu, Hockin H. K.

2015-01-01

Objectives Recurrent caries at the margins is a primary reason for restoration failure. The objectives of this study were to develop bonding agent with the double benefits of antibacterial and remineralizing capabilities, to investigate the effects of NACP filler level and solution pH on Ca and P ion release from adhesive, and to examine the antibacterial and dentin bond properties. Methods Nanoparticles of amorphous calcium phosphate (NACP) and a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM) were synthesized. Scotchbond Multi-Purpose (SBMP) primer and adhesive served as control. DMADDM was incorporated into primer and adhesive at 5% by mass. NACP was incorporated into adhesive at filler mass fractions of 10%, 20%, 30% and 40%. A dental plaque microcosm biofilm model was used to test the antibacterial bonding agents. Calcium (Ca) and phosphate (P) ion releases from the cured adhesive samples were measured vs. filler level and solution pH of 7, 5.5 and 4. Results Adding 5% DMADDM and 10–40% NACP into bonding agent, and water-aging for 28 days, did not affect dentin bond strength, compared to SBMP control at 1 day (p > 0.1). Adding DMADDM into bonding agent substantially decreased the biofilm metabolic activity and lactic acid production. Total microorganisms, total streptococci, and mutans streptococci were greatly reduced for bonding agents containing DMADDM. Increasing NACP filler level from 10% to 40% in adhesive increased the Ca and P ion release by an order of magnitude. Decreasing solution pH from 7 to 4 increased the ion release from adhesive by 6–10 folds. Significance Bonding agents containing antibacterial DMADDM and remineralizer NACP were formulated to have Ca and P ion release, which increased with NACP filler level from 10% to 40% in adhesive. NACP adhesive was “smart” and dramatically increased the ion release at cariogenic pH 4, when these ions would be most-needed to inhibit caries. Therefore, bonding agent

Wound healing effect of bioactive ion released from Mg-smectite.

PubMed

Sasaki, Yu; Sathi, Gulsan Ara; Yamamoto, Osamu

2017-08-01

Bioactive ions like Mg 2+ and Si 4+ have been known as promotion factors of tissue regeneration. In the present work, Mg-smectite, consisting of Mg 2+ and Si 4+ ions, was synthesized by a solution process, and evaluated for the efficiency of the powder on wound healing in rats. White precipitates were obtained by mixing a magnesium chloride hexahydrate solution and a sodium silicate hexahydrate solution at room temperature. The precipitates mixed with a NaOH aqueous solution were subjected to hydrothermal reaction, and finally crystalline Mg-smectite powder was obtained. The crystal and molecular structure of Mg-smectite was identified by X-ray diffractometry (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The synthesized material was determined to be crystalline Mg-smectite. The amount of Mg 2+ and Si 4+ ions released from Mg-smectite in physiological saline was analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). The total amount of Si 4+ ion released from Mg-smectite was greater than that of Mg 2+ ion. To evaluate the wound healing effect of Mg-smectite, Mg-smectite powder was applied to a full-thickness surgical wound reaching the subcutaneous tissue in the rat's abdomen. At 1 and 2weeks, skin tissue was collected and subjected to histological analysis. The results for skin regeneration showed no significant difference in wound size between the control and Mg-smectite group. However, it was found that the neovascularization, collagen deposition, and maturation were notedly accelerated by applying Mg-smectite powder in comparison with the control. Mg-smectite can then be hypothesized to stimulate the regeneration of skin tissue by releasing Mg 2+ and Si 4+ ions. These results suggested that Mg-smectite could offer great potential as a wound dressing material. Copyright © 2017 Elsevier B.V. All rights reserved.

Glucose release in mantle tissue of Mytilus: regulation by calcium ions.

PubMed

Crespo, C A; Espinosa, J

1990-09-01

Glucose release activity in mantle tissue of Mytilus galloprovincialis was studied. Mantle tissue shows a basal glucose releasing activity. The external Ca2+ absence increases 2 to 3-fold the basal glucose release, and when A23187 (10 microM) was simultaneously present the release doubled that obtained in Ca2(+)-absence. EGTA (2 mM), chlorpromazine (200 microM) and lanthanum (3 mM) decreased the glucose release promoted by external Ca2+ absence. This and other data suggest that glucose release activity in mantle tissue might be controlled by Ca2+ ions.

Triggered metal ion release and oxidation: Ferrocene as new mechanophore in polymers.

PubMed

Di Giannantonio, Michela; Ayer, Mathieu A; Verde-Sesto, Ester; Lattuada, Marco; Weder, Christoph; Fromm, Katharina M

2018-06-13

The introduction of mechanophores into polymers allows transducing mechanical forces into chemical reactions for e.g. self-healing, catalytic activity, or mechanochromic response. Here, the first example of mechanically induced metal ion release from a polymer is reported. Ferrocene (Fc) was incorporated as an Fe-ion releasing mechanophore into poly(methyl acrylate)s (PMAs) and polyurethanes (PUs). Sonication triggered the preferential cleavage of the polymers at the Fc units over other bonds, as shown by a kinetic study of the molar mass distribution of the cleaved Fc-containing and Fc-free reference polymers. The released and oxidized Fe2+ ions can be detected with KSCN to generate the red-colored [Fe(SCN)n(H2O)6-n)](3-n)+ or reacted with K4[Fe(CN)6] to afford Prussian blue. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical Migration Behavior of Copper-Clad Laminate and Electroless Nickel/Immersion Gold Printed Circuit Boards under Thin Electrolyte Layers

PubMed Central

Yi, Pan; Xiao, Kui; Ding, Kangkang; Dong, Chaofang; Li, Xiaogang

2017-01-01

The electrochemical migration (ECM) behavior of copper-clad laminate (PCB-Cu) and electroless nickel/immersion gold printed circuit boards (PCB-ENIG) under thin electrolyte layers of different thicknesses containing 0.1 M Na2SO4 was studied. Results showed that, under the bias voltage of 12 V, the reverse migration of ions occurred. For PCB-Cu, both copper dendrites and sulfate precipitates were found on the surface of FR-4 (board material) between two plates. Moreover, the Cu dendrite was produced between the two plates and migrated toward cathode. Compared to PCB-Cu, PCB-ENIG exhibited a higher tendency of ECM failure and suffered from seriously short circuit failure under high relative humidity (RH) environment. SKP results demonstrated that surface potentials of the anode plates were greater than those of the cathode plates, and those potentials of the two plates exhibited a descending trend as the RH increased. At the end of the paper, an electrochemical migration corrosion failure model of PCB was proposed. PMID:28772497

Effect of surface modification by nitrogen ion implantation on the electrochemical and cellular behaviors of super-elastic NiTi shape memory alloy.

PubMed

Maleki-Ghaleh, H; Khalil-Allafi, J; Sadeghpour-Motlagh, M; Shakeri, M S; Masoudfar, S; Farrokhi, A; Beygi Khosrowshahi, Y; Nadernezhad, A; Siadati, M H; Javidi, M; Shakiba, M; Aghaie, E

2014-12-01

The aim of this investigation was to enhance the biological behavior of NiTi shape memory alloy while preserving its super-elastic behavior in order to facilitate its compatibility for application in human body. The surfaces of NiTi samples were bombarded by three different nitrogen doses. Small-angle X-ray diffraction was employed for evaluating the generated phases on the bombarded surfaces. The electrochemical behaviors of the bare and surface-modified NiTi samples were studied in simulated body fluid (SBF) using electrochemical impedance and potentio-dynamic polarization tests. Ni ion release during a 2-month period of service in the SBF environment was evaluated using atomic absorption spectrometry. The cellular behavior of nitrogen-modified samples was studied using fibroblast cells. Furthermore, the effect of surface modification on super-elasticity was investigated by tensile test. The results showed the improvement of both corrosion and biological behaviors of the modified NiTi samples. However, no significant change in the super-elasticity was observed. Samples modified at 1.4E18 ion cm(-2) showed the highest corrosion resistance and the lowest Ni ion release.

Evaluation of the possible role of copper ions in drinking water in the pathogenesis of oral submucous fibrosis: a pilot study.

PubMed

Arakeri, Gururaj; Patil, Shekhar Gowda; Ramesh, D N S V; Hunasgi, Santosh; Brennan, Peter A

2014-01-01

We aimed to investigate the concentration of copper ions in drinking water and to assess whether copper has a role in the pathogenesis of oral submucous fibrosis (OSMF). We studied 50 patients with clinically and histologically diagnosed OSMF from the Yadgir district of Karnataka in India. Fifty healthy people matched for age and sex were used as controls. In both groups concentrations of copper ions in serum, saliva, and home drinking water were measured using atomic absorption spectroscopy and intelligent nephelometry technology. Serum ceruloplasmin concentrations were also estimated in both groups. The mean (SD) concentration of copper in the home drinking water of patients with OSMF was significantly higher (764.3 (445.9)μmol/L) than in the controls (305.7 (318.5)μmol/L) (p<0.001). Patients with OSMF also had a significantly higher copper concentrations in serum and saliva, and serum ceruloplasmin than controls (p<0.001). For the first time these data have shown a positive association between copper concentrations in home drinking water and OSMF. It raises the possibility that increased copper in drinking water contributes to the development of OSMF, and adds to that ingested when areca nut is chewed. Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Metal ion release from silver soldering and laser welding caused by different types of mouthwash.

PubMed

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.

Shock loading and release behavior of silicon nitride

NASA Astrophysics Data System (ADS)

Kawai, Nobuaki; Tsuru, Taiki; Hidaka, Naoto; Liu, Xun; Mashimo, Tsutomu

2015-06-01

Shock-reshock and shock-release experiments were performed on silicon nitride ceramics above and below its phase transition pressure. Experimental results clearly show the occurrence of elastic-plastic transition and phase transition during initial shock loading. The HEL and phase transition stress are determined as 11.6 GPa and 34.5 GPa, respectively. Below the phase transition point, the reshock profile consists of the single shock with short rise time, while the release profile shows the gradual release followed by more rapid one. Above the phase transition point, reshock and release behavior varies with the initial shock stress. In the case of reshock and release from about 40 GPa, the reshock structure is considerably dispersed, while the release structure shows rapid release. In the reshock profile from about 50 GPa, the formation of the shock wave with the small ramped precursor is observed. And, the release response from same condition shows initial gradual release and subsequent quite rapid one. These results would provide the information about how phase transformation kinetics effects on the reshock and release behavior.

Shock loading and release behavior of silicon nitride

NASA Astrophysics Data System (ADS)

Kawai, N.; Tsuru, T.; Hidaka, N.; Liu, X.; Mashimo, T.

2017-01-01

Shock-reshock and shock-release experiments were performed on silicon nitride ceramics above and below its phase transition pressure. Experimental results clearly show the occurrence of elastic-plastic transition and phase transition during initial shock loading. The HEL and phase transition stress are determined as 11.6 and 34.5 GPa, respectively. Below the phase transition stress, the reshock profile consists of the single shock with short rise time, while the release profile shows the gradual release followed by rapid one. Above phase transition stress, reshock and release behavior varies with the initial shock stress. In the case of reshock and release from about 40 GPa, the reshock structure is considerably dispersed, while the release structure shows rapid release. In the reshock profile from about 50 GPa, the formation of the shock wave with the small ramped precursor is observed. And, the release response from same shocked condition shows initial gradual release and subsequent quite rapid one. These results would provide the information about how phase transformation kinetics effects on the reshock and release behavior.

Periodate and hypobromite modification of Southern pine wood to improve sorption of copper ion

Treesearch

James D. McSweeny; Roger M. Rowell; George C. Chen; Thomas L. Eberhardt; Min Soo-Hong

2008-01-01

Milled southern pine wood was modified with sequential treatments of sodium periodate and sodium hypobromite for the purpose of improving copper ion (Cu2+) sorption capacity of the wood when tested in 24-h equilibrium batch tests. The modified wood provided additional carboxyl groups to those in the native wood and substantially increased Cu2+ uptake over that of...

Ion release and mechanical properties of calcium silicate and calcium hydroxide materials used for pulp capping.

PubMed

Natale, L C; Rodrigues, M C; Xavier, T A; Simões, A; de Souza, D N; Braga, R R

2015-01-01

To compare the ion release and mechanical properties of a calcium hydroxide (Dycal) and two calcium silicate (MTA Angelus and Biodentine) cements. Calcium and hydroxyl ion release in water from 24-h set cements were calculated from titration with HCl (n = 3). Calcium release after 7, 14, 21 and 28 days at pH 5.5 and 7.0 was measured using ICP-OES (n = 6). Flexural strength (FS) and modulus (E) were tested after 48-h storage, and compressive strength (CS) was tested after 48 h and 7 days (n = 10). Ion release and mechanical data were subjected to anova/Tukey and Kruskal-Wallis/Mann-Whitney tests, respectively (α = 0.05). Titration curves revealed that Dycal released significantly fewer ions in solution than calcium silicates (P < 0.001). Calcium release remained constant at pH 7.0, whilst at pH 5.5, it dropped significantly by 24% after 21 days (P < 0.05). At pH 5.5, MTA Angelus released significantly more calcium than Dycal (P < 0.01), whilst Biodentine had superior ion release than Dycal at pH 7.0 (P < 0.01). Biodentine had superior flexural strength, flexural modulus and compressive strength than the other cements, whilst MTA Angelus had higher modulus than Dycal (P < 0.001). Immediate calcium and hydroxyl ion release in solution was significantly lower for Dycal. In general, all materials released constant calcium levels over 28 days, but release from Dycal was significantly lower than Biodentine and MTA Angelus depending on pH conditions. Biodentine had substantially higher strength and modulus than MTA Angelus and Dycal, both of which demonstrated low stress-bearing capabilities. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Crystallization Behavior of Copper Smelter Slag During Molten Oxidation

NASA Astrophysics Data System (ADS)

Fan, Yong; Shibata, Etsuro; Iizuka, Atsushi; Nakamura, Takashi

2015-10-01

Copper slag is composed of iron silicate obtained by smelting copper concentrate and silica flux. One of the most important criteria for the utilization of this secondary resource is the recovery of iron from the slag matrix to decrease the volume of dumped slag. The molten oxidation process with crushing magnetic separation appears to be a more sustainable approach and is based on directly blowing oxidizing gas onto molten slag after the copper smelting process. In the current study, using an infrared furnace, the crystallization behavior of the slag during molten oxidation was studied to better understand the trade-off between magnetite and hematite precipitations, as assessed by X-ray diffraction (using an internal standard). Furthermore, the crystal morphology was examined using a laser microscope and Raman imaging system to understand the iron oxide transformation, and the distribution of impurities such as Cu, Zn, As, Cr, and Pb were complemented with scanning electron microscopy and energy dispersive spectroscopy. In addition, the reaction mechanism was investigated with a focus on the oxidation processes.

Some effects of gas adsorption on the high temperature volatile release behavior of a terrestrial basalt, tektite and lunar soil

NASA Technical Reports Server (NTRS)

Graham, D. G.; Muenow, D. W.; Gibson, E. K., Jr.

1979-01-01

Mass pyrograms obtained from high-temperature, mass psectrometric pyrolysis of a glassy theoleiitic submarine basalt and a tektite, ground in air to less than 64 microns, have shown N2 and SO release patterns very similar to those from the pyrolysis of mature lunar soil fines. The N2 and CO release behavior from the terrestrial samples reproduces the biomodal, high-temperature (approximately 700 and 1050 C) features from the lunar samples. Unground portions of the basalt and tektite show no release of N2 and CO during pyrolysis. Grinding also alters the release behavior and absolute amounts of H2O and CO2. It is suggested that adsorption of atmospheric gases in addition to solar wind implantation of ions may account for the wide range of values in previously reported concentrations of carbon and nitrogen from lunar fines.

Anti-cancer activity of ZnO chips by sustained zinc ion release.

PubMed

Moon, Seong-Hee; Choi, Won Jin; Choi, Sik-Won; Kim, Eun Hye; Kim, Jiyeon; Lee, Jeong-O; Kim, Seong Hwan

2016-01-01

We report anti-cancer activity of ZnO thin-film-coated chips by sustained release of zinc ions. ZnO chips were fabricated by precisely tuning ZnO thickness using atomic layer deposition, and their potential to release zinc ions relative to the number of deposition cycles was evaluated. ZnO chips exhibited selective cytotoxicity in human B lymphocyte Raji cells while having no effect on human peripheral blood mononuclear cells. Of importance, the half-maximal inhibitory concentration of the ZnO chip on the viability of Raji cells was 121.5 cycles, which was comparable to 65.7 nM of daunorubicin, an anti-cancer drug for leukemia. Molecular analysis of cells treated with ZnO chips revealed that zinc ions released from the chips increased cellular levels of reactive oxygen species, including hydrogen peroxide, which led to the down-regulation of anti-apoptotic molecules (such as HIF-1α, survivin, cIAP-2, claspin, p-53, and XIAP) and caspase-dependent apoptosis. Because the anti-cancer activity of ZnO chips and the mode of action were comparable to those of daunorubicin, the development and optimization of ZnO chips that gradually release zinc ions might have clinical anti-cancer potential. A further understanding of the biological action of ZnO-related products is crucial for designing safe biomaterials with applications in disease treatment.

Dispersive liquid-liquid microextraction of copper ions as neocuproine complex in environmental aqueous samples.

PubMed

Shariati, Shahab; Golshekan, Mostafa

2011-06-01

In the present study, a simple and efficient extraction method based on dispersive liquid-liquid microextraction prior to UV-Vis spectrophotometry was developed for the preconcentration and determination of copper ions in environmental samples. Briefly, cupric ions (Cu II) were reduced to cuprous (Cu I) with addition of hydroxyl amine hydrochloride and formed hydrophobic chelates with neocuproine. Then, a proper mixture of acetonitrile (as dispersive solvent) and choloroform (as extraction solvent) was rapidly injected into the solution and a cloudy solution was formed. After centrifuging, choloroform was sedimented at the bottom of a conical tube and diluted with 100 µL of methanol for further UV-Vis spectrophotometry measurement. An orthogonal array design (OAD) was employed to study the effects of different parameters on the extraction efficiency. Under the optimum experimental conditions, a preconcentration factor up to 63.6 was achieved for extraction from 5.0 mL of sample solution. The limit of detection (LOD) based on S/N = 3 was 0.33 µg L-1 and the calibration curve was linear in the range of 1-200 µg L-1 with reasonable linearity (r2 > 0.997). Finally, the accuracy of the proposed method was successfully evaluated by determination of trace amounts of copper ions in different water samples and satisfactory results were obtained.

Zinc stress induces copper depletion in Acinetobacter baumannii.

PubMed

Hassan, Karl A; Pederick, Victoria G; Elbourne, Liam D H; Paulsen, Ian T; Paton, James C; McDevitt, Christopher A; Eijkelkamp, Bart A

2017-03-11

The first row transition metal ions zinc and copper are essential to the survival of many organisms, although in excess these ions are associated with significant toxicity. Here, we examined the impact of zinc and copper stress on Acinetobacter baumannii, a common opportunistic pathogen. We show that extracellular zinc stress induces a copper-specific depletion phenotype in A. baumannii ATCC 17978. Supplementation with copper not only fails to rescue this phenotype, but further exacerbates the copper depletion. Extensive analysis of the A. baumannii ATCC 17978 genome identified 13 putative zinc/copper resistance efflux pumps. Transcriptional analyses show that four of these transporters are responsive to zinc stress, five to copper stress and seven to the combination of zinc and copper stress, thereby revealing a likely foundation for the zinc-induced copper starvation in A. baumannii. In addition, we show that zinc and copper play crucial roles in management of oxidative stress and the membrane composition of A. baumannii. Further, we reveal that zinc and copper play distinct roles in macrophage-mediated killing of this pathogen. Collectively, this study supports the targeting of metal ion homeostatic mechanisms as an effective antimicrobial strategy against multi-drug resistant bacterial pathogens.

Antibacterial activity and ion release of bonding agent containing amorphous calcium phosphate nanoparticles.

PubMed

Chen, Chen; Weir, Michael D; Cheng, Lei; Lin, Nancy J; Lin-Gibson, Sheng; Chow, Laurence C; Zhou, Xuedong; Xu, Hockin H K

2014-08-01

Recurrent caries at the margins is a primary reason for restoration failure. The objectives of this study were to develop bonding agent with the double benefits of antibacterial and remineralizing capabilities, to investigate the effects of NACP filler level and solution pH on Ca and P ion release from adhesive, and to examine the antibacterial and dentin bond properties. Nanoparticles of amorphous calcium phosphate (NACP) and a quaternary ammonium monomer (dimethylaminododecyl methacrylate, DMADDM) were synthesized. Scotchbond Multi-Purpose (SBMP) primer and adhesive served as control. DMADDM was incorporated into primer and adhesive at 5% by mass. NACP was incorporated into adhesive at filler mass fractions of 10%, 20%, 30% and 40%. A dental plaque microcosm biofilm model was used to test the antibacterial bonding agents. Calcium (Ca) and phosphate (P) ion releases from the cured adhesive samples were measured vs. filler level and solution pH of 7, 5.5 and 4. Adding 5% DMADDM and 10-40% NACP into bonding agent, and water-aging for 28 days, did not affect dentin bond strength, compared to SBMP control at 1 day (p>0.1). Adding DMADDM into bonding agent substantially decreased the biofilm metabolic activity and lactic acid production. Total microorganisms, total streptococci, and mutans streptococci were greatly reduced for bonding agents containing DMADDM. Increasing NACP filler level from 10% to 40% in adhesive increased the Ca and P ion release by an order of magnitude. Decreasing solution pH from 7 to 4 increased the ion release from adhesive by 6-10 folds. Bonding agents containing antibacterial DMADDM and remineralizer NACP were formulated to have Ca and P ion release, which increased with NACP filler level from 10% to 40% in adhesive. NACP adhesive was "smart" and dramatically increased the ion release at cariogenic pH 4, when these ions would be most-needed to inhibit caries. Therefore, bonding agent containing DMADDM and NACP may be promising to inhibit

Enhancing the Electrochemical Behavior of Pure Copper by Cyclic Potentiodynamic Passivation: A Comparison between Coarse- and Nano-Grained Pure Copper

NASA Astrophysics Data System (ADS)

Fattah-alhosseini, Arash; Imantalab, Omid; Attarzadeh, Farid Reza

2016-10-01

Electrochemical behavior of coarse- and nano-grained pure copper were modified and improved to a large extent by the application of cyclic potentiodynamic passivation. The efficacy of this method was evaluated on the basis of grain size which is of great importance in corrosion studies. In this study, the eight passes of accumulative roll bonding process at room temperature were successfully performed to produce nano-grained pure copper. Transmission electron microscopy image indicated that the average grain size reached below 100 nm after eight passes. On the basis of cyclic voltammetry and also the electrochemical tests performed after that, it was revealed that cyclic potentiodynamic passivation had a significant improving effect on the passive behavior of both coarse- and nano-grained samples. In addition, a superior behavior of nano-grained sample in comparison to coarse-grained one was distinguished by its smaller cyclic voltammogram loops, nobler free potentials, larger capacitive arcs in the Nyquist plots, and less charge carrier densities within the passive film.

New insights into single-compound and binary adsorption of copper and lead ions on a treated sea mango shell: experimental and theoretical studies.

PubMed

Sellaoui, Lotfi; Edi Soetaredjo, Felycia; Ismadji, Suryadi; Cláudio Lima, Éder; Dotto, Guilherme L; Ben Lamine, Abdelmottaleb; Erto, Alessandro

2017-10-04

Herein, adsorption isotherms of Pb(ii) and Cu(ii) ions on treated sea mango fruit in both single-compound and binary systems were experimentally realized at different temperatures in the range of 30-50 °C. Experimental results show that adsorption of Pb(ii) was more as compared to that of Cu(ii) ions; however, for both ions, a significant reduction in the adsorption capacity was observed in the binary system as compared to that in the single-compound systems. Moreover, under all the investigated conditions, adsorption seems to be promoted by an increase in temperature. To understand and interpret the experimental evidences, the Hill and competitive Hill models developed on the basis of the grand canonical ensemble were applied for the analysis of adsorption equilibrium data. These models contain some physicochemical parameters that allow an exhaustive analysis of the dynamics of single-compound and binary adsorptions. Based on the fitting results, in particular, through the evaluation of the number of ions bonded per site (n and n i ), it was found that lead and copper ions interacted by inclined and horizontal positions on treated sea mango in single-compound and binary systems, respectively. In addition, based on the same parameters, a significant interaction between ions was retrieved. A study focused on the saturation adsorption capacity in single-compound and binary systems affirmed that the adsorbent was more selective for lead than for copper. The reduction of the adsorbed capacity ratio between the binary and single-compound systems (i.e. Q b /Q s ) explained and confirmed that an inhibition effect between copper and lead ions at the same receptor site occurred. Finally, based on the energetic investigations, it was deduced that the adsorption energy represented the dominant factor promoting the greater adsorption of lead than that of copper in both systems.

COPPER RESEARCH UPDATE

EPA Science Inventory

This presentation provides an update and overview of new research results and remaining research needs with respect to copper corrosion control issues. The topics to be covered include: occurrence of elevated copper release in systems that meet the Action Level; impact of water c...

Combined copper/zinc attachment to prion protein

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Bernholc, Jerry

2013-03-01

Misfolding of prion protein (PrP) is responsible for diseases such as ``mad-cow disease'' in cattle and Creutzfeldt-Jacob in humans. Extensive experimental investigation has established that this protein strongly interacts with copper ions, and this ability has been linked to its still unknown function. Attachment of other metal ions (zinc, iron, manganese) have been demonstrated as well, but none of them could outcompete copper. Recent finding, however, indicates that at intermediate concentrations both copper and zinc ions can attach to the PrP at the octarepeat region, which contains high affinity metal binding sites. Based on this evidence, we have performed density functional theory simulations to investigate the combined Cu/Zn attachment. We consider all previously reported binding modes of copper at the octarepeat region and examine a possibility simultaneous Cu/Zn attachment. We find that this can indeed occur for only one of the known binding sites, when copper changes its coordination mode to allow for attachment of zinc ion. The implications of the simultaneous attachment on neural function remain to be explored.

Developmental toxicity of Japanese medaka embryos by silver nanoparticles and released ions in the presence of humic acid.

PubMed

Kim, Jun Y; Kim, Ki-Tae; Lee, Byeong G; Lim, Byung J; Kim, Sang D

2013-06-01

The final destination point of nanoparticles is the environment, where they remain a long period; therefore, a deep understanding of the relationship between nanoparticles and the environmental factors is required. Japanese medaka embryos were exposed to two differently prepared AgNPs: freshly prepared AgNPs and aged AgNPs. With these two AgNP preparations, we studied the impacts of humic acid in terms of embryonic toxicity, as well as the behavior of AgNPs. Aged AgNPs exhibited a lower lethal concentration (LC50) value (1.44mg/L) compared to fresh AgNPs (3.53mg/L) through 96h acute toxicity tests, due to the release of silver ions, as confirmed by kinetic analysis. The presence of humic acids considerably reduced the toxicity of aged AgNPs due to complexation with silver ions. Agglomeration, induced by interactions with humic acid, might reduce the bioavailability of AgNPs to Japanese medaka embryos. This study demonstrates that aged AgNPs releasing more silver ions are more toxic than fresh AgNPs, and humic acids play a role in reducing the toxicity of aged AgNPs. Copyright © 2013 Elsevier Inc. All rights reserved.

Copper and Copper Proteins in Parkinson's Disease

PubMed Central

Rivera-Mancia, Susana; Diaz-Ruiz, Araceli; Tristan-Lopez, Luis; Rios, Camilo

2014-01-01

Copper is a transition metal that has been linked to pathological and beneficial effects in neurodegenerative diseases. In Parkinson's disease, free copper is related to increased oxidative stress, alpha-synuclein oligomerization, and Lewy body formation. Decreased copper along with increased iron has been found in substantia nigra and caudate nucleus of Parkinson's disease patients. Copper influences iron content in the brain through ferroxidase ceruloplasmin activity; therefore decreased protein-bound copper in brain may enhance iron accumulation and the associated oxidative stress. The function of other copper-binding proteins such as Cu/Zn-SOD and metallothioneins is also beneficial to prevent neurodegeneration. Copper may regulate neurotransmission since it is released after neuronal stimulus and the metal is able to modulate the function of NMDA and GABA A receptors. Some of the proteins involved in copper transport are the transporters CTR1, ATP7A, and ATP7B and the chaperone ATOX1. There is limited information about the role of those biomolecules in the pathophysiology of Parkinson's disease; for instance, it is known that CTR1 is decreased in substantia nigra pars compacta in Parkinson's disease and that a mutation in ATP7B could be associated with Parkinson's disease. Regarding copper-related therapies, copper supplementation can represent a plausible alternative, while copper chelation may even aggravate the pathology. PMID:24672633

Statistical Characterization of Commercial 18650-Format Lithium-Ion Cell Thermal Runaway Behavior Based on Calorimetric Testing Results

NASA Technical Reports Server (NTRS)

Walker, William; Darst, John; Finegan, Donal; Bayles, Gary; Johnson, Kenneth; Darcy, Eric; Rickman, Steven

2018-01-01

Effective thermal management systems, designed to handle the impacts of thermal runaway (TR) and to prevent cell-to-cell propagation, are key to safe operation of lithium-ion (Li-ion) battery assemblies. Critical factors for optimizing these systems include the total energy released during a single cell TR event and the fraction of the total energy that is released through the cell casing vs. through the ejecta material. A unique calorimeter was utilized to examine the TR behavior of a statistically significant number of 18650-format Li-ion cells with varying manufacturers, chemistries, and capacities. The calorimeter was designed to contain the TR energy in a format conducive to discerning the fractions of energy released through the cell casing vs. through the ejecta material. Other benefits of this calorimeter included the ability to rapidly test of large quantities of cells and the intentional minimization of secondary combustion effects. High energy (270 Wh kg-1) and moderate energy (200 Wh kg-1) 18650 cells were tested. Some of the cells had an imbedded short circuit (ISC) device installed to aid in the examination of TR mechanisms under more realistic conditions. Other variations included cells with bottom vent (BV) features and cells with thin casings (0.22 l(1/4)m). After combining the data gathered with the calorimeter, a statistical approach was used to examine the probability of certain TR behavior, and the associated energy distributions, as a function of capacity, venting features, cell casing thickness and temperature.?

Experimental Studies of the Effects of Anode Composition and Process Parameters on Anode Slime Adhesion and Cathode Copper Purity by Performing Copper Electrorefining in a Pilot-Scale Cell

NASA Astrophysics Data System (ADS)

Zeng, Weizhi; Wang, Shijie; Free, Michael L.

2016-10-01

Copper electrorefining tests were conducted in a pilot-scale cell under commercial tankhouse environment to study the effects of anode compositions, current density, cathode blank width, and flow rate on anode slime behavior and cathode copper purity. Three different types of anodes (high, mid, and low impurity levels) were used in the tests and were analyzed under SEM/EDS. The harvested copper cathodes were weighed and analyzed for impurities concentrations using DC Arc. The adhered slimes and released slimes were collected, weighed, and analyzed for compositions using ICP. It was shown that the lead-to-arsenic ratio in the anodes affects the sintering and coalescence of slime particles. High current density condition can improve anode slime adhesion and cathode purity by intensifying slime particles' coalescence and dissolving part of the particles. Wide cathode blanks can raise the anodic current densities significantly and result in massive release of large slime particle aggregates, which are not likely to contaminate the cathode copper. Low flow rate can cause anode passivation and increase local temperatures in front of the anode, which leads to very intense sintering and coalescence of slime particles. The results and analyses of the tests present potential solutions for industrial copper electrorefining process.

Influence of oxygen, albumin and pH on copper dissolution in a simulated uterine fluid.

PubMed

Bastidas, D M; Cano, E; Mora, E M

2005-06-01

The aim of this paper is to study the influence of albumin content, from 5 to 45 g/L, on copper dissolution and compounds composition in a simulated uterine solution. Experiments were performed in atmospheric pressure conditions and with an additional oxygen pressure of 0.2 atmospheres, at 6.3 and 8.0 pH values, and at a temperature of 37 +/- 0.1 degrees C for 1, 3, 7, and 30 days experimentation time. The copper dissolution rate has been determined using absorbance measurements, finding the highest value for pH 8.0, 35 g/L albumin, and with an additional oxygen pressure of 0.2 atmospheres: 674 microg/day for 1 day, and 301 microg/day for 30 days. X-ray photoelectron spectroscopy (XPS) results show copper(II) as the main copper oxidation state at pH 8.0; and copper(I) and metallic copper at pH 6.3. The presence of albumin up to 35 g/L, accelerates copper dissolution. For high albumin content a stabilisation on the copper dissolution takes place. Corrosion product layer morphology is poorly protective, showing paths through which copper ions can release.

The effect of platform switching on the levels of metal ion release from different implant–abutment couples

PubMed Central

Alrabeah, Ghada O; Knowles, Jonathan C; Petridis, Haralampos

2016-01-01

The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (P<0.05). Titanium was the highest element to be released regardless of abutment size or connection (P<0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples. PMID:27357323

Study of coagulation processes of selected humic acids under copper ions influence*

NASA Astrophysics Data System (ADS)

Boguta, Patrycja; Sokolowska, Zofia

2013-04-01

Humic acids have limited sorption capacity and big dose of metal or other mineral component which can be sorbed on humic acids, can cause saturation of negative, surface charge of humic acids leading to destabilization of dissolved humic acids compounds. Destabilisation can be observed as coagulation and floculation proces of humic acids. However there are a lot of mechanisms which causing precipitation of humic acids. Thereby, in order to full description of coagulation process, different methods should be applied. Ordinarily, humic acids coagulation is studied by measurement of absorbance, transmittance or carbon loss in solution. Meanwhile, very significant information is also variation of metal content in soil solution and information whether metal goes to precipitate together with humic acids or stays in dissolved form in solution. So, that, from one side, processes of stronger accumulation of metal can lead to soil degradation and micronutrient deficiency for plants. However, there is also possibility to stay metal in solution in toxic and bioavailable form for plants. Main aim of this paper was to study coagulation process of different humic acids extracted from mucking peats under copper ions influence at adjusted pH to 5. In order to this, four peaty-muck soils were taken from selected places in east part of Poland (meadows and river valleys). These soils differed by humification degree, secondary transformation, density and pH. At next step, humic acids were extracted from soils using sodium hydroxide (NaOH) extractant. After exact purification by washing with HF-HCl mixture and water, humic acids were liofilized. Solutions of humic acids were prepared at concentration 40 mg/dm3 with addition of different amount of copper ions to obtain final concentration of Cu(II) ranged from 0-40mg/dm3. After 24 hours solutions were investigated using measurements of absorbance at 470nm (UV-VIS spectrometer Jasco V-530), measurements of organic carbon in solution

Photolytic Release of Dissolved Vanadium and Copper from Resuspended Coastal Marine Sediments

NASA Astrophysics Data System (ADS)

Skrabal, S. A.; Hammaker, S. N.; McBurney, A. W.; Avery, G. B., Jr.; Kieber, R. J.; Mead, R. N.

2016-02-01

Sunlight photolysis engenders release of dissolved vanadium (V), copper (Cu), and dissolved organic carbon (DOC) from a wide variety of resuspendable coastal marine sediments. Net photoreleases after 6 h of simulated sunlight were as high as 12 nM for Cu and as high as 15 nM for V. Release of Cu significantly correlated with sediment Cu. Photoreleased Cu (but not V) correlated with sediment Fe content, suggesting that photoreduction of Fe oxide carrier phases may be an important photoproduction mechanism for Cu. Longer term experiments showed continued release of metals that were not immediately readsorbed back onto sediments after 24 h of irradiation suggesting that photoproduced metals persist in the dissolved phase and are not immediately scavenged onto particles. Experiments utilizing differing total suspended sediment (TSS) levels show that, although higher TSS causes more photoproduction of Cu and V, the amount produced per mass of sediment is greatest at the lowest TSS. Vanadium photoproduction increased in Macondo oil-amended sediments compared to controls after a one-month incubation period suggesting that the oil may be a source of this metal to the water column. These results imply that photoproduction is an unrecognized source of the micronutrient metals Cu and V to coastal waters.

Developing on-site paper colorimetric monitoring technique for quick evaluating copper ion concentration in mineral wastewater

NASA Astrophysics Data System (ADS)

Liu, Guokun; Peng, Jingji; Zheng, Hong; Yuan, Dongxing

2018-05-01

With the reinforce of the copper mining, the on-site monitoring of the accompanied effluent discharge is highly demanded for the emergency response to minimize the negative effect of the effluent on the surrounding ecosystem. On the basis of the specific interaction between Cu2+ and L-Cysteine (L-Cys), which was modified on gold nanoparticles (Au NPs), and the aggregation dependent surface plasmon resonance (SPR) of Au NPs, we developed an easy-on-going paper colorimetric method for the quick evaluating the copper ion concentration in the waste water excreted from the copper mine. The color change of L-Cys modified Au NPs (L-Cys-Au NPs)immobilized on a filter paper was very sensitive to the Cu2+ concentration and free of interference from other metal ions typically in waste water. The proposed paper colorimetry has the LOD of 0.09 mg/L and the linear range of 0.1-10 mg/L, respectively, with the RSD (n = 5) was 6.6% for 1 mg/L Cu2+ and 3.5% for 5 mg/L Cu2+. The quantitative analysis results for the mineral wastewater is in good agreement the China National Environmental Protection Standards HJ485-2009, which indicates the current method could be developed to the on-site detection technique for the emergency response in monitoring Cu2+ in industrial wastewater or polluted water.

Release of Micronized Copper Particles from Pressure Treated Wood Products.

EPA Science Inventory

Micronized copper pressure treated lumber (PTL) has recently been introduced to the consumer market as a replacement for ionized copper PTL. The presence of particulate rather than aqueous copper raises concerns about possible human or environmental exposure. Two common pathways ...

Ion release, fluoride charge of and adhesion of an orthodontic cement paste containing microcapsules.

PubMed

Burbank, Brant D; Slater, Michael; Kava, Alyssa; Doyle, James; McHale, William A; Latta, Mark A; Gross, Stephen M

2016-02-01

Dental materials capable of releasing calcium, phosphate and fluoride are of great interest for remineralization. Microencapsulated aqueous solutions of these ions in orthodontic cement demonstrate slow, sustained release by passive diffusion through a permeable membrane without the need for dissolution or etching of fillers. The potential to charge a dental material formulated with microencapsulated water with fluoride by toothbrushing with over the counter toothpaste and the effect of microcapsules on cement adhesion to enamel was determined. Orthodontic cements that contained microcapsules with water and controls without microcapsules were brushed with over-the-counter toothpaste and fluoride release was measured. Adhesion measurements were performed loading orthodontic brackets to failure. Cements that contained microencapsulated solutions of 5.0M Ca(NO3)2, 0.8M NaF, 6.0MK2HPO4 or a mixture of all three were prepared. Ion release profiles were measured as a function of time. A greater fluoride charge and re-release from toothbrushing was demonstrated compared to a control with no microcapsules. Adhesion of an orthodontic cement that contained microencapsulated remineralizing agents was 8.5±2.5MPa compared to the control without microcapsules which was of 8.3±1.7MPa. Sustained release of fluoride, calcium and phosphate ions from cement formulated with microencapsulated remineralizing agents was demonstrated. Orthodontic cements with microcapsules show a release of bioavailable fluoride, calcium, and phosphate ions near the tooth surface while having the ability to charge with fluoride and not effect the adhesion of the material to enamel. Incorporation of microcapsules in dental materials is promising for promoting remineralization. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of N-acetyl-L-cysteine capped Mn:doped CdS quantum dots for quantitative detection of copper ions

NASA Astrophysics Data System (ADS)

Yang, Xiupei; Jia, Zhihui; Cheng, Xiumei; Luo, Na; Choi, Martin M. F.

2018-06-01

In this work, a new assembled copper ions sensor based on the Mn metal-enhanced fluorescence of N-acetyl-L-cysteine protected CdS quantum dots (NAC-Mn:CdS QDs) was developed. The NAC and Mn:CdS QDs nanoparticles were assembled into NAC-Mn:CdS QDs complexes through the formation of Cdsbnd S and Mnsbnd S bonds. As compared to NAC capped CdS QDs, higher fluorescence quantum yields of NAC-Mn:CdS QDs was observed, which is attributed to the surface plasmon resonance of Mn metal. In addition, the fluorescence intensity of as-formed complexes weakened in the presence of copper ions. The decrease in fluorescence intensity presented a linear relationship with copper ions concentration in the range from 0.16-3.36 μM with a detection limit of 0.041 μM . The characterization of as-formed QDs was analyzed by photoluminescence (PL), ultra violet-visible (UV-vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) respectively. Furthermore, the recoveries and relative standard deviations of Cu2+ spiked in real water samples for the intra-day and inter-day analyses were 88.20-117.90, 95.20-109.90, 0.80-5.80 and 1.20-3.20%, respectively. Such a metal-enhanced QDs fluorescence system may have promising application in chemical and biological sensors.

Adsorption of Copper Ion using Acrylic Acid-g-Polyaniline in Aqueous Solution

NASA Astrophysics Data System (ADS)

Kamarudin, Sabariah; Mohammad, Masita

2018-04-01

A conductive polymer, polyaniline (PANI) has unique electrical behaviour, stable in the environment, easy synthesis and have wide application in various fields. Modification of PANI in order to improve its adsorption capacity has been done. In this study, the polyaniline-grafted acrylic acid has been prepared and followed by adsorption of copper ion in aqueous solution. Acrylic acid, PANI and acrylic acid-g-polyaniline (Aag-PANI) were characterized by FTIR and SEM to determine its characteristic. The adsorption capacity was investigated to study the removal capacity of Cu ion from aqueous solution. Two parameters were selected which are pH (2, 4 and 6) and initial metal ion concentration (50 mg/L, 100 mg/L and 200 mg/L). The maximum adsorption capacity for PANI and Aag-PANI are 1.7 mg/g and 64.6 mg/g, respectively, at an initial concentration of 100 mg/L. The Langmuir adsorption isotherm model and Freundlich adsorption isotherm model have been used and showed that it is heterolayer adsorption by follows the Freundlich isotherm model.

Swift heavy ion irradiation of interstellar dust analogues. Small carbonaceous species released by cosmic rays

NASA Astrophysics Data System (ADS)

Dartois, E.; Chabot, M.; Pino, T.; Béroff, K.; Godard, M.; Severin, D.; Bender, M.; Trautmann, C.

2017-03-01

Context. Interstellar dust grain particles are immersed in vacuum ultraviolet (VUV) and cosmic ray radiation environments influencing their physicochemical composition. Owing to the energetic ionizing interactions, carbonaceous dust particles release fragments that have direct impact on the gas phase chemistry. Aims: The exposure of carbonaceous dust analogues to cosmic rays is simulated in the laboratory by irradiating films of hydrogenated amorphous carbon interstellar analogues with energetic ions. New species formed and released into the gas phase are explored. Methods: Thin carbonaceous interstellar dust analogues were irradiated with gold (950 MeV), xenon (630 MeV), and carbon (43 MeV) ions at the GSI UNILAC accelerator. The evolution of the dust analogues is monitored in situ as a function of fluence at 40, 100, and 300 K. Effects on the solid phase are studied by means of infrared spectroscopy complemented by simultaneously recording mass spectrometry of species released into the gas phase. Results: Specific species produced and released under the ion beam are analyzed. Cross sections derived from ion-solid interaction processes are implemented in an astrophysical context.

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

PubMed

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

2008-04-01

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

Release of Micronized Copper Particles from Pressure Treated Wood Products

EPA Science Inventory

Micronized copper pressure treated lumber (PTL) has recently been introduced to the consumer market as a replacement for ionized copper PTL. The presence of particulate rather than aqueous copper raises concerns about the exposure of humans as well as the environment to the parti...

The delivery of copper for thylakoid import observed by NMR

PubMed Central

Banci, Lucia; Bertini, Ivano; Ciofi-Baffoni, Simone; Kandias, Nikolaos G.; Robinson, Nigel J.; Spyroulias, Georgios A.; Su, Xun-Cheng; Tottey, Stephen; Vanarotti, Murugendra

2006-01-01

The thylakoid compartments of plant chloroplasts are a vital destination for copper. Copper is needed to form holo-plastocyanin, which must shuttle electrons between photosystems to convert light into biologically useful chemical energy. Copper can bind tightly to proteins, so it has been hypothesized that copper partitions onto ligand-exchange pathways to reach intracellular locations without inflicting damage en route. The copper metallochaperone Atx1 of chloroplast-related cyanobacteria (ScAtx1) engages in bacterial two-hybrid interactions with N-terminal domains of copper-transporting ATPases CtaA (cell import) and PacS (thylakoid import). Here we visualize copper delivery. The N-terminal domain PacSN has a ferredoxin-like fold that forms copper-dependent heterodimers with ScAtx1. Removal of copper, by the addition of the cuprous-ion chelator bathocuproine disulfonate, disrupts this heterodimer, as shown from a reduction of the overall tumbling rate of the protein mixture. The NMR spectral changes of the heterodimer versus the separate proteins reveal that loops 1, 3, and 5 (the carboxyl tail) of the ScAtx1 Cu(I) site switch to an apo-like configuration in the heterodimer. NMR data (2JNH couplings in the imidazole ring of 15N ScAtx1 His-61) also show that His-61, bound to copper(I) in [Cu(I)ScAtx1]2, is not coordinated to copper in the heterodimer. A model for the PacSN/Cu(I)/ScAtx1 complex is presented. Contact with PacSN induces change to the ScAtx1 copper-coordination sphere that drives copper release for thylakoid import. These data also elaborate on the mechanism to keep copper(I) out of the ZiaAN ATPase zinc sites. PMID:16707580

Metallic ions released from stainless steel, nickel-free, and titanium orthodontic alloys: toxicity and DNA damage.

PubMed

Ortiz, Antonio José; Fernández, Esther; Vicente, Ascensión; Calvo, José L; Ortiz, Clara

2011-09-01

The aims of this study were to determine the amounts of metallic ions that stainless steel, nickel-free, and titanium alloys release to a culture medium, and to evaluate the cellular viability and DNA damage of cultivated human fibroblasts with those mediums. The metals were extracted from 10 samples (each consisting of 4 buccal tubes and 20 brackets) of the 3 orthodontic alloys that were submerged for 30 days in minimum essential medium. Next, the determination of metals was performed by using inductively coupled plasma mass spectrometry, cellular viability was assessed by using the tetrazolium reduction assay (MTT assay) (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide), and DNA damage was determined with the Comet assay. The metals measured in all the samples were Ti(47), Cr(52), Mn(55), Co(59), Ni(60), Mo(92), Fe(56), Cu(63), Zn(66), As(75), Se(78), Cd(111), and Pb(208). The cellular viability of the cultured fibroblasts incubated for 7 days with minimum essential medium, with the stainless steel alloy submerged, was close to 0%. Moreover, high concentrations of titanium, chromium, manganese, cobalt, nickel, molybdenum, iron, copper, and zinc were detected. The nickel-free alloy released lower amounts of ions to the medium. The greatest damage in the cellular DNA, measured as the olive moment, was also produced by the stainless steel alloy followed by the nickel-free alloy. Conversely, the titanium alloy had an increased cellular viability and did not damage the cellular DNA, as compared with the control values. The titanium brackets and tubes are the most biocompatible of the 3 alloys studied. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Effects of Ion-Releasing Tooth-Coating Material on Demineralization of Bovine Tooth Enamel

PubMed Central

Kawasaki, Koji; Kambara, Masaki

2014-01-01

We compared the effect of a novel ion-releasing tooth-coating material that contained S-PRG (surface-reaction type prereacted glass-ionomer) filler to that of non-S-PRG filler and nail varnish on the demineralization of bovine enamel subsurface lesions. The demineralization process of bovine enamel was examined using quantitative light-induced fluorescence (QLF) and electron probe microanalyzer (EPMA) measurement. Ion concentrations in demineralizing solution were measured using inductively coupled plasma atomic (ICP) emission spectrometry and an ion electrode. The nail varnish group and the non-S-PRG filler group showed linear demineralization. Although the nail varnish group and the non-S-PRG filler group showed linear demineralization, the S-PRG filler group did not. Further, plane-scanning by EPMA analysis in the S-PRG filler group showed no changes in Ca ion distribution, and F ions showed peak levels on the surface of enamel specimens. Most ions in the demineralizing solution were present at higher concentrations in the S-PRG filler group than in the other two groups. In conclusion, only the S-PRG filler-containing tooth-coating material released ions and inhibited demineralization around the coating. PMID:24578706

Preparation of 3D nanoporous copper-supported cuprous oxide for high-performance lithium ion battery anodes.

PubMed

Liu, Dequan; Yang, Zhibo; Wang, Peng; Li, Fei; Wang, Desheng; He, Deyan

2013-03-07

Three-dimensional (3D) nanoporous architectures can provide efficient and rapid pathways for Li-ion and electron transport as well as short solid-state diffusion lengths in lithium ion batteries (LIBs). In this work, 3D nanoporous copper-supported cuprous oxide was successfully fabricated by low-cost selective etching of an electron-beam melted Cu(50)Al(50) alloy and subsequent in situ thermal oxidation. The architecture was used as an anode in lithium ion batteries. In the first cycle, the sample delivered an extremely high lithium storage capacity of about 2.35 mA h cm(-2). A high reversible capacity of 1.45 mA h cm(-2) was achieved after 120 cycles. This work develops a promising approach to building reliable 3D nanostructured electrodes for high-performance lithium ion batteries.

Graphene sponge decorated with copper nanoparticles as a novel bactericidal filter for inactivation of Escherichia coli.

PubMed

Deng, Can-Hui; Gong, Ji-Lai; Zeng, Guang-Ming; Zhang, Peng; Song, Biao; Zhang, Xue-Gang; Liu, Hong-Yu; Huan, Shuang-Yan

2017-10-01

Nanotechnology has great potential in water purification. However, the limitations such as aggregation and toxicity of nanomaterials have blocked their practical application. In this work, a novel copper nanoparticles-decorated graphene sponge (Cu-GS) was synthesized using a facile hydrothermal method. Cu-GS consisting of three-dimensional (3D) porous graphene network and well-dispersed Cu nanoparticles exhibited high antibacterial efficiency against Esherichia coli when used as a bactericidal filter. The morphological changes determined by scanning electron microscope and fluorescence images measured by flow cytometry confirmed the involvement of membrane damage induced by Cu-GS in their antibacterial process. The oxidative ability of Cu-GS and intercellular reactive oxygen species (ROS) were also determined to elucidate the possible antibacterial mechanism of Cu-GS. Moreover, the concentration of released copper ions from Cu-GS was far below the drinking water standard, and the copper ions also have an effect on the antibacterial activity of Cu-GS. Results suggested that Cu-GS as a novel bactericidal filter possessed a potential application of water disinfection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Silver-Ion-Exchanged Nanostructured Zeolite X as Antibacterial Agent with Superior Ion Release Kinetics and Efficacy against Methicillin-Resistant Staphylococcus aureus.

PubMed

Chen, Shaojiang; Popovich, John; Iannuzo, Natalie; Haydel, Shelley E; Seo, Dong-Kyun

2017-11-15

As antibiotic resistance continues to be a major public health problem, antimicrobial alternatives have become critically important. Nanostructured zeolites have been considered as an ideal host for improving popular antimicrobial silver-ion-exchanged zeolites, because with very short diffusion path lengths they offer advantages in ion diffusion and release over their conventional microsized zeolite counterparts. Herein, comprehensive studies are reported on materials characteristics, silver-ion release kinetics, and antibacterial properties of silver-ion-exchanged nanostructured zeolite X with comparisons to conventional microsized silver-ion-exchanged zeolite (∼2 μm) as a reference. The nanostructured zeolites are submicrometer-sized aggregates (100-700 nm) made up of primary zeolite particles with an average primary particle size of 24 nm. The silver-ion-exchanged nanostructured zeolite released twice the concentration of silver ions at a rate approximately three times faster than the reference. The material exhibited rapid antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) with minimum inhibitory concentration (MIC) values ranging from 4 to 16 μg/mL after 24 h exposure in various growth media and a minimum bactericidal concentration (MBC; >99.9% population reduction) of 1 μg/mL after 2 h in water. While high concentrations of silver-ion-exchanged nanostructured zeolite X were ineffective at reducing MRSA biofilm cell viability, efficacy increased at lower concentrations. In consideration of potential medical applications, cytotoxicity of the silver-ion-exchanged nanostructured zeolite X was also investigated. After 4 days of incubation, significant reduction in eukaryotic cell viability was observed only at concentrations 4-16-fold greater than the 24 h MIC, indicating low cytotoxicity of the material. Our results establish silver-ion-exchanged nanostructured zeolites as an effective antibacterial material against dangerous

Human cytoplasmic copper chaperones Atox1 and CCS exchange copper ions in vitro.

PubMed

Petzoldt, Svenja; Kahra, Dana; Kovermann, Michael; Dingeldein, Artur P G; Niemiec, Moritz S; Ådén, Jörgen; Wittung-Stafshede, Pernilla

2015-06-01

After Ctr1-mediated copper ion (Cu) entry into the human cytoplasm, chaperones Atox1 and CCS deliver Cu to P1B-type ATPases and to superoxide dismutase, respectively, via direct protein-protein interactions. Although the two Cu chaperones are presumed to work along independent pathways, we here assessed cross-reactivity between Atox1 and the first domain of CCS (CCS1) using biochemical and biophysical methods in vitro. By NMR we show that CCS1 is monomeric although it elutes differently from Atox1 in size exclusion chromatography (SEC). This property allows separation of Atox1 and CCS1 by SEC and, combined with the 254/280 nm ratio as an indicator of Cu loading, we demonstrate that Cu can be transferred from one protein to the other. Cu exchange also occurs with full-length CCS and, as expected, the interaction involves the metal binding sites since mutation of Cu-binding cysteine in Atox1 eliminates Cu transfer from CCS1. Cross-reactivity between CCS and Atox1 may aid in regulation of Cu distribution in the cytoplasm.

Roles of Copper-Binding Proteins in Breast Cancer.

PubMed

Blockhuys, Stéphanie; Wittung-Stafshede, Pernilla

2017-04-20

Copper ions are needed in several steps of cancer progression. However, the underlying mechanisms, and involved copper-binding proteins, are mainly elusive. Since most copper ions in the body (in and outside cells) are protein-bound, it is important to investigate what copper-binding proteins participate and, for these, how they are loaded with copper by copper transport proteins. Mechanistic information for how some copper-binding proteins, such as extracellular lysyl oxidase (LOX), play roles in cancer have been elucidated but there is still much to learn from a biophysical molecular viewpoint. Here we provide a summary of copper-binding proteins and discuss ones reported to have roles in cancer. We specifically focus on how copper-binding proteins such as mediator of cell motility 1 (MEMO1), LOX, LOX-like proteins, and secreted protein acidic and rich in cysteine (SPARC) modulate breast cancer from molecular and clinical aspects. Because of the importance of copper for invasion/migration processes, which are key components of cancer metastasis, further insights into the actions of copper-binding proteins may provide new targets to combat cancer.

Effect of flow rate and lead/copper pipe sequence on lead release from service lines.

PubMed

Cartier, Clément; Arnold, Roger B; Triantafyllidou, Simoni; Prévost, Michèle; Edwards, Marc

2012-09-01

A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antibacterial activity of agricultural waste derived wollastonite doped with copper for bone tissue engineering.

PubMed

Azeena, S; Subhapradha, N; Selvamurugan, N; Narayan, S; Srinivasan, N; Murugesan, R; Chung, T W; Moorthi, A

2017-02-01

Bioactive ceramic materials with metal ions generation brought great attention in the class of biomaterials development and widely employed as a filler material for bone tissue regeneration. The present study aimed to fabricate calcium silicate based ceramic material doped with copper metal particles by sol-gel method. Rice straw of agricultural waste was utilized as a source material to synthesize wollastonite, then wollastonite was doped with copper to fabricate copper doped wollastonite (Cu-Ws) particles. The synthesized materials were subjected to physio-chemical characterization by TEM, DLS, FTIR, XRD and DSC analysis. It was found that the sizes of the WS particles was around 900nm, while adding copper the size was increased upto 1184nm and the addition of copper to the material sharpening the peak. The release of Cu ions was estimated by ICP analysis. The anti-bacterial potentiality of the particles suggested that better microbial growth inhibition against E. coli (Gram negative) and S. aureus (Gram positive) strains from ATCC, in which the growth inhibition was more significant against S. aureus. The biocompatibility in mouse Mesenchymal Stem cells (mMSC) showed the non-toxic effect up to 0.05mg/ml concentration while the increase in concentration was found to be toxic to the cells. So the particles may have better potential application with the challenging prevention of post implantation infection in the field of bone tissue engineering (BTE). Copyright © 2016. Published by Elsevier B.V.

Fixation effects on the release of copper, chromium and arsenic from CCA-C treated marine piles

Treesearch

Stan Lebow

1999-01-01

This study sought to determine the effect of fixation time and temperature on the release of copper, chromium and arsenic from treated marine piles immersed in seawater under "worst case" conditions. Sections of piles were CCA-C treated to a target retention of 2.5 lbs/ft3) (40 kg/m3) and then allowed to Condition at 36°F (2°C) for either 3, 7 or 20 days. As...

A novel XRF method to measure environmental release of copper and zinc from antifouling paints.

PubMed

Ytreberg, Erik; Lagerström, Maria; Holmqvist, Albin; Eklund, Britta; Elwing, Hans; Dahlström, Magnus; Dahl, Peter; Dahlström, Mia

2017-06-01

The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF K α net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Release of copper from embedded solid copper bullets into muscle and fat tissues of fallow deer (Dama dama), roe deer (Capreolus capreolus), and wild boar (Sus scrofa) and effect of copper content on oxidative stability of heat-processed meat.

PubMed

Schuhmann-Irschik, I; Sager, M; Paulsen, P; Tichy, A; Bauer, F

2015-10-01

When venison with embedded copper bullets was subjected to different culinary processing procedures, the amount of copper released from the embedded bullet was affected more by the retention period of the bullet in the meat during cool storage, than by the different heating protocols. The presence of copper fragments had no significant effect on levels of thiobarbituric acid reactive substances (TBARS). Conversely, TBARS in lean meat (fallow deer, wild boar, roe deer) were significantly affected by culinary treatment (higher TBARS in boiled and boiled-stored meat than in meat barbecued or boiled in brine). In pork-beef patties doped with up to 28mg/kg Cu, TBARS increased after dry-heating and subsequently storing the meat patties. The amount of copper doping had no effect on TBARS for 0 and 7days of storage, but a significant effect at day 14 (fat oxidation retarded at higher Cu doses). Evidence is presented that wild boar meat may be more sensitive to fat oxidation than pork-beef. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the Ni-Ion release rate from surfaces of binary NiTi shape memory alloys

NASA Astrophysics Data System (ADS)

Ševčíková, Jana; Bártková, Denisa; Goldbergová, Monika; Kuběnová, Monika; Čermák, Jiří; Frenzel, Jan; Weiser, Adam; Dlouhý, Antonín

2018-01-01

The study is focused on Ni-ion release rates from NiTi surfaces exposed in the cell culture media and human vascular endothelial cell (HUVEC) culture environments. The NiTi surface layers situated in the depth of 70 μm below a NiTi oxide scale are affected by interactions between the NiTi alloys and the bio-environments. The finding was proved with use of inductively coupled plasma mass spectrometry and electron microscopy experiments. As the exclusive factor controlling the Ni-ion release rates was not only thicknesses of the oxide scale, but also the passivation depth, which was two-fold larger. Our experimental data strongly suggested that some other factors, in addition to the Ni concentration in the oxide scale, admittedly hydrogen soaking deep below the oxide scale, must be taken into account in order to rationalize the concentrations of Ni-ions released into the bio-environments. The suggested role of hydrogen as the surface passivation agent is also in line with the fact that the Ni-ion release rates considerably decrease in NiTi samples that were annealed in controlled hydrogen atmospheres prior to bio-environmental exposures.

Determination of factors responsible for the bioweathering of copper minerals from organic-rich copper-bearing Kupferschiefer black shale.

PubMed

Włodarczyk, Agnieszka; Szymańska, Agata; Skłodowska, Aleksandra; Matlakowska, Renata

2016-04-01

The aim of this study was to investigate the bioweathering of copper minerals present in the alkaline, copper-bearing and organic-rich Kupferschiefer black shale through the action of a consortium of indigenous lithobiontic, heterotrophic, neutrophilic bacteria isolated from this sedimentary rock. The involvement of microorganisms in the direct/enzymatic bioweathering of fossil organic matter of the rock was confirmed. As a result of bacterial activity, a spectrum of various organic compounds such as urea and phosphoric acid tributyl ester were released from the rock. These compounds indirectly act on the copper minerals occurring in the rock and cause them to weather. This process was reflected in the mobilization of copper, iron and sulfur and in changes in the appearance of copper minerals observed under reflected light. The potential role of identified enzymes in biodegradation of fossil organic matter and role of organic compounds released from black shale as a result of this process in copper minerals weathering was discussed. The presented results provide a new insight into the role of chemical compounds released by bacteria during fossil organic matter bioweathering potentially important in the cycling of copper and iron deposited in the sedimentary rock. The originality of the described phenomenon lies in the fact that the bioweathering of fossil organic matter and, consequently, of copper minerals occur simultaneously in the same environment, without any additional sources of energy, electrons and carbon. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of Ions released from Three Types of Orthodontic Brackets immersed in Different Mouthwashes: An in vitro Study.

PubMed

Nahidh, Mohammed; Garma, Noor Mh; Jasim, Esraa S

2018-01-01

Herbs are used widely in medicine. The purpose of the present study was to assess the ion release from gold-plated orthodontic bracket compared with other stainless steel brackets, and based on the findings of the study, the orthodontists can choose the most biocompatible brackets and mouthwashes useful in the clinical practice. A total of 150 orthodontic brackets from Orthotechnology™ Company, USA (50 stainless steel one-piece brackets, 50 stainless steel two-piece brackets, and 50 gold brackets) were immersed in four mouthwashes in addition to distilled water. Ten of each type of brackets in every media were immersed under 37°C for 45 days. Ions released in these mouthwashes were measured, and comparisons among different bracket types and among various mouthwashes were done by one-way analysis of variance (ANOVA) and then with Games-Howell tests. Increased amounts of ions released in herbal mouth-washes were recorded in gold and two-piece brackets in comparison with one-piece stainless steel brackets. Herbal mouthwashes must be used with caution as they showed an increased amount of ions released in comparison with chlorhexidine. One-piece stainless steel bracket system is the most compatible bracket type, as they released the least amount of ions. One-piece stainless steel brackets are better than two-piece brackets in terms of ions released.

Antimicrobial Activity of Silver Ions Released from Zeolites Immobilized on Cellulose Nanofiber Mats.

PubMed

Rieger, Katrina A; Cho, Hong Je; Yeung, Hiu Fai; Fan, Wei; Schiffman, Jessica D

2016-02-10

In this study, we exploit the high silver ion exchange capability of Linde Type A (LTA) zeolites and present, for the first time, electrospun nanofiber mats decorated with in-house synthesized silver (Ag(+)) ion exchanged zeolites that function as molecular delivery vehicles. LTA-Large zeolites with a particle size of 6.0 μm were grown on the surface of the cellulose nanofiber mats, whereas LTA-Small zeolites (0.2 μm) and three-dimensionally ordered mesoporous-imprinted (LTA-Meso) zeolites (0.5 μm) were attached to the surface of the cellulose nanofiber mats postsynthesis. After the three zeolite/nanofiber mat assemblies were ion-exchanged with Ag(+) ions, their ion release profiles and ability to inactivate Escherichia coli (E. coli) K12 were evaluated as a function of time. LTA-Large zeolites immobilized on the nanofiber mats displayed more than an 11 times greater E. coli K12 inactivation than the Ag-LTA-Large zeolites that were not immobilized on the nanofiber mats. This study demonstrates that by decorating nanometer to micrometer scale Ag(+) ion-exchanged zeolites on the surface of high porosity, hydrophilic cellulose nanofiber mats, we can achieve a tunable release of Ag(+) ions that inactivate bacteria faster and are more practical to use in applications over powder zeolites.

Assessment of the Bioaccessibility of Micronized Copper Wood on Simulated Stomach Fluid

EPA Pesticide Factsheets

The widespread use of copper-treated lumber has increased the potential for human exposure. Moreover, there is a lack of information on the fate and behavior of copper-treated wood particles following oral ingestion. In this study, the in vitro bioaccessibility of copper from copper-treated wood dust in simulated stomach fluid and DI water was determined. Three copper-treated wood products, liquid alkali copper quaternary and two micronized copper quarternary from different manufacturers, were incubated in the extraction media then fractionated by centrifugation and filtration through 0.45 ?m and 10 kDa filters. The copper concentrations from isolated fractions were measured using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Total amounts of copper from each wood product were also determined using microwave-assisted acid digestion of dried wood samples and quantification using ICP-OES. The percent in vitro bioaccessible copper was between 83 and 90 % for all treated wood types. However, the percent of copper released in DI water was between 14 and 25 % for all wood products. This data suggests that copper is highly bioaccessible at low pH and may pose a potential human exposure risk upon ingestion. This dataset is associated with the following publication:Santiago-Rodrigues, L., J.L. Griggs, K. Bradham , C. Nelson , T. Luxton , W. Platten , and K. Rogers. Assessment of the bioaccessibility of micronized copper wood in synthetic stomach flu

Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva.

PubMed

Tahmasbi, Soodeh; Sheikh, Tahereh; Hemmati, Yasamin B

2017-03-01

To investigate the galvanic corrosion of brackets manufactured by four different companies coupled with stainless steel (SS) or nickel-titanium (NiTi) wires in an artificial saliva solution. A total of 24 mandibular central incisor Roth brackets of four different manufacturers (American Orthodontics, Dentaurum, Shinye, ORJ) were used in this experimental study. These brackets were immersed in artificial saliva along with SS or NiTi orthodontic wires (0.016'', round) for 28 days. The electric potential difference of each bracket/ wire coupled with a saturated calomel reference electrode was measured via a voltmeter and recorded constantly. Corrosion rate (CR) was calculated, and release of ions was measured with an atomic absorption spectrometer. Stereomicroscope was used to evaluate all samples. Then, samples with corrosion were further assessed by scanning electron microscope and energy-dispersive X-ray spectroscopy. Two-way analysis of variance was used to analyze data. Among ions evaluated, release of nickel ions from Shinye brackets was significantly higher than that of other brackets. The mean potential difference was significantly lower in specimens containing a couple of Shinye brackets and SS wire compared with other specimens. No significant difference was observed in the mean CR of various groups (p > 0.05). Microscopic evaluation showed corrosion in two samples only: Shinye bracket coupled with SS wire and American Orthodontics bracket coupled with NiTi wire. Shinye brackets coupled with SS wire showed more susceptibility to galvanic corrosion. There were no significant differences among specimens in terms of the CR or released ions except the release of Ni ions, which was higher in Shinye brackets.

Ion release from, and fluoride recharge of a composite with a fluoride-containing bioactive glass.

PubMed

Davis, Harry B; Gwinner, Fernanda; Mitchell, John C; Ferracane, Jack L

2014-10-01

Materials that are capable of releasing ions such as calcium and fluoride, that are necessary for remineralization of dentin and enamel, have been the topic of intensive research for many years. The source of calcium has most often been some form of calcium phosphate, and that for fluoride has been one of several metal fluoride or hexafluorophosphate salts. Fluoride-containing bioactive glass (BAG) prepared by the sol-gel method acts as a single source of both calcium and fluoride ions in aqueous solutions. The objective of this investigation was to determine if BAG, when added to a composite formulation, can be used as a single source for calcium and fluoride ion release over an extended time period, and to determine if the BAG-containing composite can be recharged upon exposure to a solution of 5000ppm fluoride. BAG 61 (61% Si; 31% Ca; 4% P; 3% F; 1% B) and BAG 81 (81% Si; 11% Ca; 4% P; 3% F; 1% B) were synthesized by the sol-gel method. The composite used was composed of 50/50 Bis-GMA/TEGDMA, 0.8% EDMAB, 0.4% CQ, and 0.05% BHT, combined with a mixture of BAG (15%) and strontium glass (85%) to a total filler load of 72% by weight. Disks were prepared, allowed to age for 24h, abraded, then placed into DI water. Calcium and fluoride release was measured by atomic absorption spectroscopy and fluoride ion selective electrode methods, respectively, after 2, 22, and 222h. The composite samples were then soaked for 5min in an aqueous 5000ppm fluoride solution, after which calcium and fluoride release was again measured at 2, 22, and 222h time points. Prior to fluoride recharge, release of fluoride ions was similar for the BAG 61 and BAG 81 composites after 2h, and also similar after 22h. At the four subsequent time points, one prior to, and three following fluoride recharge, the BAG 81 composite released significantly more fluoride ions (p<0.05). Both composites were recharged by exposure to 5000ppm fluoride, although the BAG 81 composite was recharged more than the BAG

Study on the mechanism of copper-ammonia complex decomposition in struvite formation process and enhanced ammonia and copper removal.

PubMed

Peng, Cong; Chai, Liyuan; Tang, Chongjian; Min, Xiaobo; Song, Yuxia; Duan, Chengshan; Yu, Cheng

2017-01-01

Heavy metals and ammonia are difficult to remove from wastewater, as they easily combine into refractory complexes. The struvite formation method (SFM) was applied for the complex decomposition and simultaneous removal of heavy metal and ammonia. The results indicated that ammonia deprivation by SFM was the key factor leading to the decomposition of the copper-ammonia complex ion. Ammonia was separated from solution as crystalline struvite, and the copper mainly co-precipitated as copper hydroxide together with struvite. Hydrogen bonding and electrostatic attraction were considered to be the main surface interactions between struvite and copper hydroxide. Hydrogen bonding was concluded to be the key factor leading to the co-precipitation. In addition, incorporation of copper ions into the struvite crystal also occurred during the treatment process. Copyright © 2016. Published by Elsevier B.V.

Factors affecting catalysis of copper corrosion products in NDMA formation from DMA in simulated premise plumbing.

PubMed

Zhang, Hong; Andrews, Susan A

2013-11-01

This study investigated the effects of corrosion products of copper, a metal commonly employed in household plumbing systems, on N-nitrosodimethylamine (NDMA) formation from a known NDMA precursor, dimethylamine (DMA). Copper-catalyzed NDMA formation increased with increasing copper concentrations, DMA concentrations, alkalinity and hardness, but decreased with increasing natural organic matter (NOM) concentration. pH influenced the speciation of chloramine and the interactions of copper with DMA. The transformation of monochloramine (NH2Cl) to dichloramine and complexation of copper with DMA were involved in elevating the formation of NDMA by copper at pH 7.0. The inhibiting effect of NOM on copper catalysis was attributed to the rapid consumption of NH2Cl by NOM and/or the competitive complexation of NOM with copper to limit the formation of DMA-copper complexes. Hardness ions, as represented by Ca(2+), also competed with copper for binding sites on NOM, thereby weakening the inhibitory effect of NOM on NDMA formation. Common copper corrosion products also participated in these reactions but in different ways. Aqueous copper released from malachite [Cu2CO3(OH)2] was shown to promote NDMA formation while NDMA formation decreased in the presence of CuO, most likely due to the adsorption of DMA. Copyright © 2013 Elsevier Ltd. All rights reserved.

A selective potentiometric copper (II) ion sensor based on the functionalized ZnO nanorods.

PubMed

Khun, K; Ibupoto, Z H; Liu, X; Nur, O; Willander, M; Danielsson, B

2014-09-01

In this work, ZnO nanorods were hydrothermally grown on the gold-coated glass substrate and characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. The ZnO nanorods were functionalized by two different approaches and performance of the sensor electrode was monitored. Fourier transform infrared spectroscopy (FTIR) was carried out for the confirmation of interaction between the ionophore molecules and ZnO nanorods. In addition to this, the surface of the electrode was characterized by X-ray photoelectron spectroscopy (XPS) showing the chemical and electronic state of the ionophore and ZnO nanorod components. The ionophore solution was prepared in the stabilizer, poly vinyl chloride (PVC) and additives, and then functionalized on the ZnO nanorods that have shown the Nernstian response with the slope of 31 mV/decade. However, the Cu2+ ion sensor was fabricated only by immobilizing the selective copper ion ionophore membrane without the use of PVC, plasticizers, additives and stabilizers and the sensor electrode showed a linear potentiometric response with a slope of 56.4 mV/decade within a large dynamic concentration range (from 1.0 x 10(-6) to 1.0 x 10(-1) M) of copper (II) nitrate solutions. The sensor showed excellent repeatability and reproducibility with response time of less than 10 s. The negligible response to potentially interfering metal ions such as calcium (Ca2+), magnesium (Mg2+), potassium (K+), iron (Fe3+), zinc (Zn2+), and sodium (Na+) allows this sensor to be used in biological studies. It may also be used as an indicator electrode in the potentiometric titration.

THE IMPACT OF HEXAMETAPHOSPHATE ON COPPER CORROSION AND RELEASE

EPA Science Inventory

In 1991, U.S. Environmental Protection Agency (U.S. EPA) promulgated the Lead and Copper Rule, which established a copper action level of 1.3 mg/L in a 1-liter, first-draw sample collected from the consumer’s tap (Federal Register, 1991a, 1991b, 1992). The rule was established d...

Target-specific copper hybrid T7 phage particles.

PubMed

Dasa, Siva Sai Krishna; Jin, Qiaoling; Chen, Chin-Tu; Chen, Liaohai

2012-12-18

Target-specific nanoparticles have attracted significant attention recently, and have greatly impacted life and physical sciences as new agents for imaging, diagnosis, and therapy, as well as building blocks for the assembly of novel complex materials. While most of these particles are synthesized by chemical conjugation of an affinity reagent to polymer or inorganic nanoparticles, we are promoting the use of phage particles as a carrier to host organic or inorganic functional components, as well as to display the affinity reagent on the phage surface, taking advantage of the fact that some phages host well-established vectors for protein expression. An affinity reagent can be structured in a desired geometry on the surface of phage particles, and more importantly, the number of the affinity reagent molecules per phage particle can be precisely controlled. We previously have reported the use of the T7 phage capsid as a template for synthesizing target-specific metal nanoparticles. In this study herein, we reported the synthesis of nanoparticles using an intact T7 phage as a scaffold from which to extend 415 copies of a peptide that contains a hexahistidine (6His) motif for capture of copper ions and staging the conversion of copper ions to copper metal, and a cyclic Arginine-Glycine-Aspartic Acid (RGD4C) motif for targeting integrin and cancer cells. We demonstrated that the recombinant phage could load copper ions under low bulk copper concentrations without interfering with its target specificity. Further reduction of copper ions to copper metal rendered a very stable copper hybrid T7 phage, which prevents the detachment of copper from phage particles and maintains the phage structural integrity even under harsh conditions. Cancer cells (MCF-7) can selectively uptake copper hybrid T7 phage particles through ligand-mediated transmembrane transportation, whereas normal control cells (MCF-12F) uptake 1000-fold less. We further demonstrated that copper hybrid T7

Ion release from magnesium materials in physiological solutions under different oxygen tensions.

PubMed

Feyerabend, Frank; Drücker, Heiko; Laipple, Daniel; Vogt, Carla; Stekker, Michael; Hort, Norbert; Willumeit, Regine

2012-01-01

Although magnesium as degradable biomaterial already showed clinical proof of concepts, the design of new alloys requires predictive in vitro methods, which are still lacking. Incubation under cell culture conditions to obtain "physiological" corrosion may be a solution. The aim of this study was to analyse the influence of different solutions, addition of proteins and of oxygen availability on the corrosion of different magnesium materials (pure Mg, WE43, and E11) with different surface finishing. Oxygen content in solution, pH, osmolality and ion release were determined. Corrosion led to a reduction of oxygen in solution. The influence of oxygen on pH was enhanced by proteins, while osmolality was not influenced. Magnesium ion release was solution-dependent and enhanced in the initial phase by proteins with delayed release of alloying elements. The main corrosion product formed was magnesium carbonate. Therefore, cell culture conditions are proposed as first step toward physiological corrosion.

Transition-metal prion protein attachment: Competition with copper

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Bernholc, Jerry

2012-02-01

Prion protein, PrP, is a protein capable of binding copper ions in multiple modes depending on their concentration. Misfolded PrP is implicated in a group of neurodegenerative diseases, which include ``mad cow disease'' and its human form, variant Creutzfeld-Jacob disease. An increasing amount of evidence suggests that attachment of non-copper metal ions to PrP triggers transformations to abnormal forms similar to those observed in prion diseases. In this work, we use hybrid Kohn-Sham/orbital-free density functional theory simulations to investigate copper replacement by other transition metals that bind to PrP, including zinc, iron and manganese. We consider all known copper binding modes in the N-terminal domain of PrP. Our calculations identify modes most susceptible to copper replacement and reveal metals that can successfully compete with copper for attachment to PrP.

Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

PubMed Central

Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

2011-01-01

Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

Loading and release of amine drugs by ion-exchange fibers: role of amine type.

PubMed

Gao, Yanan; Liu, Hongzhuo; Yuan, Jing; Yang, Yang; Che, Xin; Hou, Yanlong; Li, Sanming

2014-04-01

With more production and application of ion-exchange fibers (IEFs), it becomes necessary to understand the interaction between IEFs and amine compounds, an important group of organic drugs and structural components of large organic molecules in biological systems. However, so far few experimental studies have been conducted to systematically investigate the exchanging mechanism of amine compounds to IEFs. Therefore, 15 amine drugs were selected to investigate the effect of amine type on the loading and release of them from the related IEFs. Loading affinity of these drugs by IEFs decreased in the order of secondary, tertiary, and primary. The following items: basicity, aromaticity, molar volume, rotatability, and so on, were emphatically discussed to address the underlying mechanism of drug loading and releasing extent and rate of IEFs. It was evident that strong alkaline drugs strengthened the ionic bond between the amine groups and IEFs, and thus the loading affinity. These results will advance the understanding of the exchanging behavior of IEFs in the drug delivery system. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Lead and Copper Control 101

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

Copper removal using electrosterically stabilized nanocrystalline cellulose.

PubMed

Sheikhi, Amir; Safari, Salman; Yang, Han; van de Ven, Theo G M

2015-06-03

Removal of heavy metal ions such as copper using an efficient and low-cost method with low ecological footprint is a critical process in wastewater treatment, which can be achieved in a liquid phase using nanoadsorbents such as inorganic nanoparticles. Recently, attention has turned toward developing sustainable and environmentally friendly nanoadsorbents to remove heavy metal ions from aqueous media. Electrosterically stabilized nanocrystalline cellulose (ENCC), which can be prepared from wood fibers through periodate/chlorite oxidation, has been shown to have a high charge content and colloidal stability. Here, we show that ENCC scavenges copper ions by different mechanisms depending on the ion concentration. When the Cu(II) concentration is low (C0≲200 ppm), agglomerates of starlike ENCC particles appear, which are broken into individual starlike entities by shear and Brownian motion, as evidenced by photometric dispersion analysis, dynamic light scattering, and transmission electron microscopy. On the other hand, at higher copper concentrations, the aggregate morphology changes from starlike to raftlike, which is probably due to the collapse of protruding dicarboxylic cellulose (DCC) chains and ENCC charge neutralization by copper adsorption. Such raftlike structures result from head-to-head and lateral aggregation of neutralized ENCCs as confirmed by transmission electron microscopy. As opposed to starlike aggregates, the raftlike structures grow gradually and are prone to sedimentation at copper concentrations C0≳500 ppm, which eliminates a costly separation step in wastewater treatment processes. Moreover, a copper removal capacity of ∼185 mg g(-1) was achieved thanks to the highly charged DCC polyanions protruding from ENCC. These properties along with the biorenewability make ENCC a promising candidate for wastewater treatment, in which fast, facile, and low-cost removal of heavy metal ions is desired most.

Preparation of novel multi-walled carbon nanotubes nanocomposite adsorbent via RAFT technique for the adsorption of toxic copper ions.

PubMed

Hosseinzadeh, Hossein; Pashaei, Shahryar; Hosseinzadeh, Soleyman; Khodaparast, Zahra; Ramin, Sonia; Saadat, Younes

2018-05-31

In the present work, polymer-coated multiwalled carbon nanotube (MWCNT) was prepared via RAFT method. First, a novel trithiocarbonate-based RAFT agent was prepared attached chemically into the surface of MWCNT. In addition, the RAFT co-polymerization of acrylic acid and acrylamide monomers was conducted through the prepared RAFT agent. In the next age, the surface morphology and chemical properties of the prepared components were fully examined by using FTIR, 1 HNMR, SEM, TEM, XRD and TGA/DTG techniques. Finally, the modified MWCNT composite was employed as an excellent adsorbent for the adsorption of copper (II) ions. The results indicated that ion adsorption basically relies on adsorbing time, solution pH, initial copper concentration, and adsorbent dosage. Further, the adsorption kinetics and isotherm analysis demonstrated that the adsorption mode was fitted with the pseudo-second-order and Langmuir isotherm models, respectively. Based on the results of thermodynamic study, the ion adsorption process was endothermic and spontaneous. Finally, based on the experimental results, the surface functionalized MWCNT with hydrophilic groups could be successfully used as a promising selective adsorbent material in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

[Effects of copper on biodegradation mechanism of trichloroethylene by mixed microorganisms].

PubMed

Gao, Yanhui; Zhao, Tiantao; Xing, Zhilin; He, Zhi; Zhang, Lijie; Peng, Xuya

2016-05-25

We isolated and enriched mixed microorganisms SWA1 from landfill cover soils supplemented with trichloroethylene (TCE). The microbial mixture could degrade TCE effectively under aerobic conditions. Then, we investigated the effect of copper ion (0 to 15 μmol/L) on TCE biodegradation. Results show that the maximum TCE degradation speed was 29.60 nmol/min with 95.75% degradation when copper ion was at 0.03 μmol/L. In addition, genes encoding key enzymes during biodegradation were analyzed by Real-time quantitative reverse transcription PCR (RT-qPCR). The relative expression abundance of pmoA gene (4.22E-03) and mmoX gene (9.30E-06) was the highest when copper ion was at 0.03 μmol/L. Finally, we also used MiSeq pyrosequencing to investigate the diversity of microbial community. Methylocystaceae that can co-metabolic degrade TCE were the dominant microorganisms; other microorganisms with the function of direct oxidation of TCE were also included in SWA1 and the microbial diversity decreased significantly along with increasing of copper ion concentration. Based on the above results, variation of copper ion concentration affected the composition of SWA1 and degradation mechanism of TCE. The degradation mechanism of TCE included co-metabolism degradation of methanotrophs and oxidation metabolism directly at copper ion of 0.03 μmol/L. When copper ion at 5 μmol/L (biodegradation was 84.75%), the degradation mechanism of TCE included direct-degradation and co-metabolism degradation of methanotrophs and microorganisms containing phenol hydroxylase. Therefore, biodegradation of TCE by microorganisms was a complicated process, the degradation mechanism included co-metabolism degradation of methanotrophs and bio-oxidation of non-methanotrophs.

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

PubMed

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.

Quantifying fish swimming behavior in response to acute exposure of aqueous copper using computer assisted video and digital image analysis

USGS Publications Warehouse

Calfee, Robin D.; Puglis, Holly J.; Little, Edward E.; Brumbaugh, William G.; Mebane, Christopher A.

2016-01-01

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors.

Quantifying Fish Swimming Behavior in Response to Acute Exposure of Aqueous Copper Using Computer Assisted Video and Digital Image Analysis

PubMed Central

Calfee, Robin D.; Puglis, Holly J.; Little, Edward E.; Brumbaugh, William G.; Mebane, Christopher A.

2016-01-01

Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors. PMID:26967350

Effects of caffeine on behavioral and inflammatory changes elicited by copper in zebrafish larvae: Role of adenosine receptors.

PubMed

Cruz, Fernanda Fernandes; Leite, Carlos Eduardo; Kist, Luiza Wilges; de Oliveira, Giovanna Medeiros; Bogo, Maurício Reis; Bonan, Carla Denise; Campos, Maria Martha; Morrone, Fernanda Bueno

2017-04-01

This study investigated the effects of caffeine in the behavioral and inflammatory alterations caused by copper in zebrafish larvae, attempting to correlate these changes with the modulation of adenosine receptors. To perform a survival curve, 7dpf larvae were exposed to 10μM CuSO 4 , combined to different concentrations of caffeine (100μM, 500μM and 1mM) for up to 24h. The treatment with copper showed lower survival rates only when combined with 500μM and 1mM of caffeine. We selected 4 and 24h as treatment time-points. The behavior evaluation was done by analyzing the traveled distance, the number of entries in the center, and the length of permanence in the center and the periphery of the well. The exposure to 10μM CuSO 4 plus 500μM caffeine at 4 and 24h changed the behavioral parameters. To study the inflammatory effects of caffeine, we assessed the PGE 2 levels by using UHPLC-MS/MS, and TNF, COX-2, IL-6 and IL-10 gene expression by RT-qPCR. The expression of adenosine receptors was also evaluated with RT-qPCR. When combined to copper, caffeine altered inflammatory markers depending on the time of exposure. Adenosine receptors expression was significantly increased, especially after 4h exposure to copper and caffeine together or separately. Our results demonstrated that caffeine enhances the inflammation induced by copper by decreasing animal survival, altering inflammatory markers and promoting behavioral changes in zebrafish larvae. We also conclude that alterations in adenosine receptors are related to those effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Cu-Click Compatible Triazabutadienes To Expand the Scope of Aryl Diazonium Ion Chemistry.

PubMed

Cornali, Brandon M; Kimani, Flora W; Jewett, John C

2016-10-07

Triazabutadienes can be used to readily generate reactive aryl diazonium ions under mild, physiologically relevant conditions. These conditions are compatible with a range of functionalities that do not tolerate traditional aryl diazonium ion generation. To increase the utility of this aryl diazonium ion releasing chemistry an alkyne-containing triazabutadiene was synthesized. The copper-catalyzed azide-alkyne cycloaddition ("Cu-click") reaction was utilized to modify the alkyne-containing triazabutadiene and shown to be compatible with the nitrogen-rich triazabutadiene. One of the triazole products was tethered to a fluorophore, thus enabling the direct fluorescent labeling of a model protein.

Tandem mass spectrometry of nitric oxide and hydrogen sulfide releasing aspirins: a hint into activity behavior.

PubMed

Crestoni, Maria Elisa; Chiavarino, Barbara; Guglielmo, Stefano; Lilla, Valentina; Fornarini, Simonetta

2013-01-01

Aspirin (acetylsalicylic acid, ASA) is the most popular non-steroidal anti-inflammatory drug. However, due to its action on cyclooxygenase and its acid nature, aspirin is associated with adverse gastrointestinal effects. In an effort to minimize these side effects, NO-donor and H2S-donor ASA co-drugs have been designed and tested. Their mass spectrometric behavior is now analyzed and reported. Positive ions were obtained by electrospray ionization involving protonation or alkali metal attachment. Their dissociation processes have been studied by collision induced dissociation in a triple quadrupole instrument. High mass accuracy measurements have been recorded on a Fourier transform ion cyclotron resonance mass spectrometer. The protonated molecules dissociate by an exclusive or largely prevailing path leading to acetyloxy-substituted benzoyl cation, namely an ASA unit. The process is reminiscent of the enzymatic hydrolysis, releasing intact ASA to a large extent. Only at higher collision energy does the formal ketene loss disrupt the ASA moiety. The gas phase chemistry of protonated ASA-releasing drugs develops along elementary dissociation steps analogous to the reactive processes in complex biological environments. This notion may provide a tool for preliminary testing of new compounds.

[Retrieval of Copper Pollution Information from Hyperspectral Satellite Data in a Vegetation Cover Mining Area].

PubMed

Qu, Yong-hua; Jiao, Si-hong; Liu, Su-hong; Zhu, Ye-qing

2015-11-01

Heavy metal mining activities have caused the complex influence on the ecological environment of the mining regions. For example, a large amount of acidic waste water containing heavy metal ions have be produced in the process of copper mining which can bring serious pollution to the ecological environment of the region. In the previous research work, bare soil is mainly taken as the research target when monitoring environmental pollution, and thus the effects of land surface vegetation have been ignored. It is well known that vegetation condition is one of the most important indictors to reflect the ecological change in a certain region and there is a significant linkage between the vegetation spectral characteristics and the heavy metal when the vegetation is effected by the heavy metal pollution. It means the vegetation is sensitive to heavy metal pollution by their physiological behaviors in response to the physiological ecology change of their growing environment. The conventional methods, which often rely on large amounts of field survey data and laboratorial chemical analysis, are time consuming and costing a lot of material resources. The spectrum analysis method using remote sensing technology can acquire the information of the heavy mental content in the vegetation without touching it. However, the retrieval of that information from the hyperspectral data is not an easy job due to the difficulty in figuring out the specific band, which is sensitive to the specific heavy metal, from a huge number of hyperspectral bands. Thus the selection of the sensitive band is the key of the spectrum analysis method. This paper proposed a statistical analysis method to find the feature band sensitive to heavy metal ion from the hyperspectral data and to then retrieve the metal content using the field survey data and the hyperspectral images from China Environment Satellite HJ-1. This method selected copper ion content in the leaves as the indicator of copper pollution

Analytical application of solid contact ion-selective electrodes for determination of copper and nitrate in various food products and drinking water.

PubMed

Wardak, Cecylia; Grabarczyk, Malgorzata

2016-08-02

A simple, fast and cheap method for monitoring copper and nitrate in drinking water and food products using newly developed solid contact ion-selective electrodes is proposed. Determination of copper and nitrate was performed by application of multiple standard additions technique. The reliability of the obtained results was assessed by comparing them using the anodic stripping voltammetry or spectrophotometry for the same samples. In each case, satisfactory agreement of the results was obtained, which confirms the analytical usefulness of the constructed electrodes.

Post-ion beam induced degradation of copper layers in transmission electron microscopy specimens

NASA Astrophysics Data System (ADS)

Seidel, F.; Richard, O.; Bender, H.; Vandervorst, W.

2015-11-01

Copper containing transmission electron microscopy (TEM) specimens frequently show corrosion after focused ion beam (FIB) preparation. This paper reveals that the corrosion product is a Cu-S phase growing over the specimen surface. The layer is identified by energy-dispersive x-ray spectroscopy, and lattice spacing indexing of power spectra patterns. The corrosion process is further studied by TEM on cone-shaped specimens, which are intentionally stored after FIB preparation with S flakes for short time. Furthermore, a protective method against corrosion is developed by varying the time in the FIB vacuum and the duration of a subsequent plasma cleaning.

Thermal behavior of copper processed by ECAP at elevated temperatures

NASA Astrophysics Data System (ADS)

Gonda, Viktor

2018-05-01

Large amount of strengthening can be achieved by equal channel angular pressing (ECAP), by the applied severe plastic deformation during the processing. For pure metals, this high strength is accompanied with low thermal stability due to the large activation energy for recrystallization. In the present paper, the chosen technological route was elevated temperature single pass ECAP processing of copper, and its effect on the thermal behavior during the restoration processes of the deformed samples was studied.

Micronized Copper Wood Preservatives: Efficacy of Ion, Nano, and Bulk Copper against the Brown Rot Fungus Rhodonia placenta

PubMed Central

Civardi, Chiara; Schubert, Mark; Fey, Angelika; Wick, Peter; Schwarze, Francis W. M. R.

2015-01-01

Recently introduced micronized copper (MC) formulations, consisting of a nanosized fraction of basic copper (Cu) carbonate (CuCO3·Cu(OH)2) nanoparticles (NPs), were introduced to the market for wood protection. Cu NPs may presumably be more effective against wood-destroying fungi than bulk or ionic Cu compounds. In particular, Cu- tolerant wood-destroying fungi may not recognize NPs, which may penetrate into fungal cell walls and membranes and exert their impact. The objective of this study was to assess if MC wood preservative formulations have a superior efficacy against Cu-tolerant wood-destroying fungi due to nano effects than conventional Cu biocides. After screening a range of wood-destroying fungi for their resistance to Cu, we investigated fungal growth of the Cu-tolerant fungus Rhodonia placenta in solid and liquid media and on wood treated with MC azole (MCA). In liquid cultures we evaluated the fungal response to ion, nano and bulk Cu distinguishing the ionic and particle effects by means of the Cu2+ chelator ammonium tetrathiomolybdate (TTM) and measuring fungal biomass, oxalic acid production and laccase activity of R. placenta. Our results do not support the presence of particular nano effects of MCA against R. placenta that would account for an increased antifungal efficacy, but provide evidence that attribute the main effectiveness of MCA to azoles. PMID:26554706

Micronized Copper Wood Preservatives: Efficacy of Ion, Nano, and Bulk Copper against the Brown Rot Fungus Rhodonia placenta.

PubMed

Civardi, Chiara; Schubert, Mark; Fey, Angelika; Wick, Peter; Schwarze, Francis W M R

2015-01-01

Recently introduced micronized copper (MC) formulations, consisting of a nanosized fraction of basic copper (Cu) carbonate (CuCO3·Cu(OH)2) nanoparticles (NPs), were introduced to the market for wood protection. Cu NPs may presumably be more effective against wood-destroying fungi than bulk or ionic Cu compounds. In particular, Cu- tolerant wood-destroying fungi may not recognize NPs, which may penetrate into fungal cell walls and membranes and exert their impact. The objective of this study was to assess if MC wood preservative formulations have a superior efficacy against Cu-tolerant wood-destroying fungi due to nano effects than conventional Cu biocides. After screening a range of wood-destroying fungi for their resistance to Cu, we investigated fungal growth of the Cu-tolerant fungus Rhodonia placenta in solid and liquid media and on wood treated with MC azole (MCA). In liquid cultures we evaluated the fungal response to ion, nano and bulk Cu distinguishing the ionic and particle effects by means of the Cu2+ chelator ammonium tetrathiomolybdate (TTM) and measuring fungal biomass, oxalic acid production and laccase activity of R. placenta. Our results do not support the presence of particular nano effects of MCA against R. placenta that would account for an increased antifungal efficacy, but provide evidence that attribute the main effectiveness of MCA to azoles.

Bone Cell–materials Interactions and Ni Ion Release of Anodized Equiatomic NiTi Alloy

PubMed Central

Bernard, Sheldon A.; Balla, Vamsi Krishna; Davies, Neal M.; Bose, Susmita; Bandyopadhyay, Amit

2011-01-01

Laser processed NiTi alloy was anodized for different durations in H2SO4 electrolyte with varying pH to create biocompatible surfaces with low Ni ion release as well as bioactive surfaces to enhance biocompatibility and bone cell-materials interactions. The anodized surfaces were assessed for their in vitro cell-materials interactions using human fetal osteoblast (hFOB) cells for 3, 7 and 11 days, and Ni ion release up to 8 weeks in simulated body fluids. The results were correlated with surface morphologies of anodized surfaces characterized using field-emission scanning electron microscopy (FESEM). The results show that the anodization creates a surface with nano/micro roughness depending on anodization conditions. The hydrophilicity of NiTi surface was found to improve after anodization due to lower contact angles in cell media, which dropped from 32° to < 5°. The improved wettability of anodized surfaces is further corroborated by their high surface energy comparable to that of cp Ti. Relatively high surface energy, especially polar component, and nano/micro surface features of anodized surfaces significantly increased the number of living cells and their adherence and growth on these surfaces. Finally, a significant drop in Ni ion release from 268 ± 11 to 136 ± 15 ppb was observed for NiTi surfaces after anodization. This work indicates that anodization of NiTi alloy has a positive influence on the surface energy and surface morphology, which in turn improve bone cell-materials interactions and reduce Ni ion release in vitro. PMID:21232641

Electrochemical and Passive Behaviors of Pure Copper Fabricated by Accumulative Roll-Bonding (ARB) Process

NASA Astrophysics Data System (ADS)

Imantalab, O.; Fattah-alhosseini, A.

2015-07-01

In the present work, electrochemical and passive behaviors of pure copper fabricated by accumulative roll-bonding (ARB) process in 0.01 M borax solution (pH = 9.1) have been studied. Before any electrochemical measurements, evaluation of microstructure was obtained by Vickers microhardness, x-ray diffraction (XRD), and transmission electron microscopy. The results of microhardness tests revealed that microhardness values increased with the increasing number of ARB cycles. Also a sharp increase was seen in microhardness after the first ARB cycle, whereas mediocre additional increases were observed afterward up to the seven cycles. Moreover, XRD patterns showed that the mean crystallite size values decrease with the increasing number of ARB cycles. To investigate the electrochemical and passive behaviors of the samples, the potentiodynamic polarization, Mott-Schottky analysis and electrochemical impedance spectroscopy (EIS) were carried out. Polarization plots revealed that as a result of ARB, the corrosion behavior of the specimens improves compared with the annealed pure copper. Also, the Mott-Schottky analysis and EIS measurements showed that the increasing number of ARB cycles offer better conditions for forming the passive films with higher protection behavior, due to the growth of less-defective films.

[Copper recovery from artificial bioleaching lixivium of waste printed circuit boards].

PubMed

Cheng, Dan; Zhu, Neng-Wu; Wu, Ping-Xiao; Zou, Ding-Hui; Xing, Yi-Jia

2014-04-01

The key step to realize metal recovery from bioleaching solutions is the recovery of copper from bioleaching lixivium of waste printed circuit boards in high-grade form. The influences of cathode material, current density, initial pH and initial copper ion concentration on the efficiency and energy consumption of copper recovery from artificial bioleaching lixivium under condition of constant current were investigated using an electro-deposition approach. The results showed that the larger specific surface area of the cathode material (carbon felt) led to the higher copper recovery efficiency (the recovery efficiencies of the anode and the cathode chambers were 96.56% and 99.25%, respectively) and the smaller the total and unit mass product energy consumption (the total and unit mass product energy consumptions were 0.022 kW x h and 15.71 kW x h x kg(-1), respectively). The copper recovery efficiency and energy consumption increased with the increase of current density. When the current density was 155.56 mA x cm(-2), the highest copper recovery efficiencies in the anode and cathode chambers reached 98.51% and 99.37%, respectively. Accordingly, the highest total and unit mass product energy consumptions were 0.037 kW x h and 24.34 kW x h x kg(-1), respectively. The copper recovery efficiency was also significantly affected by the initial copper ion concentration. The increase of the initial copper ion concentration would lead to faster decrease of copper ion concentration, higher total energy consumption, and lower unit mass product consumption. However, the initial pH had no significant effect on the copper recovery efficiency. Under the optimal conditions (carbon felt for cathode materials, current density of 111.11 mA x cm(-2), initial pH of 2.0, and initial copper ion concentration of 10 g x L(-1)), the copper recovery efficiencies of the anode and cathode chambers were 96.75% and 99.35%, and the total and unit mass product energy consumptions were 0.021 kW x h

The Copper Active Site of CBM33 Polysaccharide Oxygenases

PubMed Central

2013-01-01

The capacity of metal-dependent fungal and bacterial polysaccharide oxygenases, termed GH61 and CBM33, respectively, to potentiate the enzymatic degradation of cellulose opens new possibilities for the conversion of recalcitrant biomass to biofuels. GH61s have already been shown to be unique metalloenzymes containing an active site with a mononuclear copper ion coordinated by two histidines, one of which is an unusual τ-N-methylated N-terminal histidine. We now report the structural and spectroscopic characterization of the corresponding copper CBM33 enzymes. CBM33 binds copper with high affinity at a mononuclear site, significantly stabilizing the enzyme. X-band EPR spectroscopy of Cu(II)-CBM33 shows a mononuclear type 2 copper site with the copper ion in a distorted axial coordination sphere, into which azide will coordinate as evidenced by the concomitant formation of a new absorption band in the UV/vis spectrum at 390 nm. The enzyme’s three-dimensional structure contains copper, which has been photoreduced to Cu(I) by the incident X-rays, confirmed by X-ray absorption/fluorescence studies of both aqueous solution and intact crystals of Cu-CBM33. The single copper(I) ion is ligated in a T-shaped configuration by three nitrogen atoms from two histidine side chains and the amino terminus, similar to the endogenous copper coordination geometry found in fungal GH61. PMID:23540833

Biocompatibility and bond degradation of poly-acrylic acid coated copper iodide-adhesives.

PubMed

ALGhanem, Adi; Fernandes, Gabriela; Visser, Michelle; Dziak, Rosemary; Renné, Walter G; Sabatini, Camila

2017-09-01

To investigate the effect of poly-acrylic acid (PAA) copper iodide (CuI) adhesives on bond degradation, tensile strength, and biocompatibility. PAA-CuI particles were incorporated into Optibond XTR, Optibond Solo and XP Bond in 0.1 and 0.5mg/ml. Clearfil SE Protect, an MDPB-containing adhesive, was used as control. The adhesives were applied to human dentin, polymerized and restored with composite in 2mm-increments. Resin-dentin beams (0.9±0.1mm 2 ) were evaluated for micro-tensile bond strength after 24h, 6 months and 1year. Hourglass specimens (10×2×1mm) were evaluated for ultimate tensile strength (UTS). Cell metabolic function of human gingival fibroblast cells exposed to adhesive discs (8×1mm) was assessed with MTT assay. Copper release from adhesive discs (5×1mm) was evaluated with UV-vis spectrophotometer after immersion in 0.9% NaCl for 1, 3, 5, 7, 10, 14, 21 and 30 days. SEM, EDX and XRF were conducted for microstructure characterization. XTR and Solo did not show degradation when modified with PAA-CuI regardless of the concentration. The UTS for adhesives containing PAA-CuI remained unaltered relative to the controls. The percent viable cells were reduced for Solo 0.5mg/ml and XP 0.1 or 0.5mg/ml PAA-CuI. XP demonstrated the highest ion release. For all groups, the highest release was observed at days 1 and 14. PAA-CuI particles prevented the bond degradation of XTR and Solo after 1year without an effect on the UTS for any adhesive. Cell viability was affected for some adhesives. A similar pattern of copper release was demonstrated for all adhesives. Copyright © 2017. Published by Elsevier Ltd.

Plastic behavior of polycrystalline copper at optical scales of deformation

NASA Astrophysics Data System (ADS)

Domber, Jeanette Leah

Microplasticity is permanent deformation that occurs below the proportional limit of a material. For precision deployable optical spacecraft, it is unknown how microplasticity will affect the performance of the precision structure. An examination of the rolling of thin film optical reflectors indicates a strong dependence of the post-deployed shape on the strain hardening exponent of the material. However, confirmation of the valid extension of the constitutive model used to predict the deployed shape to microscopic strain regimes is necessary. The primary objective of this thesis is threefold: determine the relationship between stress and strain at nano to microstrain levels for representative materials; determine if the relationship between microscopic and macroscopic plastic behavior can be accurately characterized by the Ramberg-Osgood strain hardening constitutive model with a single set of material parameters; and determine if dislocation motion is the root cause of microplastic behavior at room temperature. The test apparatus, with a dynamic force range of 40,000 to 1, measures strains from 0.01 to 1000 parts per million (ppm) of cylindrical amorphous quartz and cold-worked and annealed tempered polycrystalline copper specimen. Elastic behavior in all three materials was consistent with typical values. However, plastic responses were larger than expected. Stresses on the order of 10 to 10,000 kPa (1.45 to 1450 psi) produced permanent strain in all three types of materials ranging from 0.01 to 1 ppm, some of which was attributable to a systematic error in the measurement. Extrapolating macroplastic behavior to lower stress and strain values underestimates the amount of microplasticity observed in the material. Therefore, material property characterization is required at all strain levels that are of concern for a particular application. The similarity in the levels of measured permanent strain for a given stress level between the as-drawn and annealed copper

Development and Evaluation of Oral Controlled Release Chlorpheniramine-Ion Exchange Resinate Suspension

PubMed Central

Kadam, A. U.; Sakarkar, D. M.; Kawtikwar, P. S.

2008-01-01

An oral controlled release suspension of chlorpheniramine maleate was prepared using ion-exchange resin technology. A strong cation exchange resin Indion 244 was utilized for the sorption of the drug and the drug resinates was evaluated for various physical and chemical parameters. The drug-resinate complex was microencapsulated with a polymer Eudragit RS 100 to further retard the release characteristics. Both the drug-resinate complex and microencapsulated drug resinate were suspended in a palatable aqueous suspension base and were evaluated for controlled release characteristic. Stability study indicated that elevated temperature did not alter the sustained release nature of the dosage form indicating that polymer membrane surrounding the core material remained intact throughout the storage period. PMID:20046790

Glucose deprivation stimulates Cu(2+) toxicity in cultured cerebellar granule neurons and Cu(2+)-dependent zinc release.

PubMed

Isaev, Nickolay K; Genrikhs, Elisaveta E; Aleksandrova, Olga P; Zelenova, Elena A; Stelmashook, Elena V

2016-05-27

Copper chloride (0.01mM, 2h) did not have significant influence on the survival of cerebellar granule neurons (CGNs) incubated in balanced salt solution. However, CuCl2 caused severe neuronal damage by glucose deprivation (GD). The glutamate NMDA-receptors blocker MK-801 partially and antioxidant N-acetyl-l-cysteine (NAC) or Zn(2+) chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) almost entirely protected CGNs from this toxic effect. Measurements of intracellular calcium ions using Fluo-4 AM, or zinc ions with FluoZin-3 AM demonstrated that 1 h-exposure to GD induced intensive increase of Fluo-4 but not FluoZin-3 fluorescence in neurons. The supplementation of solution with CuCl2 caused an increase of FluoZin-3, Fluo-4 and CellROX Green (reactive oxygen species probe) fluorescence by GD. The stimulation of Fluo-4 but not FluoZin-3 fluorescence by copper could be prevented partially by MK-801 and as well as CellROX Green fluorescence by NAC at GD. This data imply that during GD copper ions induce intense displacement zinc ions from intracellular stores, in addition free radical production, glutamate release and Ca(2+) overload of CGNs, that causes death of neurons as a result. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Stress Corrosion Cracking Control Plans. 3. Copper Alloys

DTIC Science & Technology

1975-06-01

convenience intended to include amines and all other species which can react with copper to produce the cupric -ammonium complex ion or perhap...capability of forming complexes even resembling the cupric -ammonium complex should be considered as potentially causative of SCC as ammonia unless...nitrate, acetate, tartrate , or citrate which also contain copper ions. There is some evidence that oxides of nitrogen (generating ammoniacal species

Lead and Copper Control 101-slides

EPA Science Inventory

This presentation is an overview of the most important water treatment strategies for the control of lead and copper release from drinking water corrosion. In addition to the sections specifically on lead and copper treatment, sections are included that cover sampling to find le...

Zerovalent Copper Intercalated Birnessite as a Cathode for Lithium Ion Batteries: Extending Cycle Life

DOE PAGES

Li, Yue Ru; Poyraz, Altug S.; Hu, Xiaobing; ...

2017-01-01

Birnessite type layered manganese dioxides (δ-MnO 2) have attracted considerable attention in recent years as 2D intercalation cathodes for rechargeable Li +, Na +, and Mg 2+ batteries due to fast ion diffusion through their negatively charged δ-MnO 2 sheets separated by interlayer cations and a stable Mn 3+/4+ redox couple. Here we report the preparation and electrochemistry of zero and divalent copper co-intercalated birnessite type manganese dioxide (Cu 0 0.03Cu 2+ 0.21Na 0.12MnO 2·0.9H 2O). The copper intercalated birnessite materials were fully characterized utilizing powder X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-OES), transmission electron microscopy (TEM).more » The mixed valent nature of intercalated Cu 0 and Cu 2+ was confirmed by X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS). Electrochemical evaluation results show that zero valent copper intercalated birnessite exhibits higher discharge capability, improved cyclability, and lower impedance compared to the Cu 2+ only intercalated (Cu 0.26MnO 2·1.0H 2O) and Cu free Na birnessite (Na 0.40MnO 2·1.0H 2O) materials. Remarkably, zero valent copper birnessite shows almost no fade after 10 cycles at 0.1 mV/s. Electrochemical impedance spectroscopy results suggest that charge transfer resistivity of Cu 0 modified samples was much lower than that of Cu 2+ and Cu free birnessite, indicating that the presence of a small amount of Cu 0 improves the conductivity of birnessite and results in better electrochemical cyclability, rate capability, and lower impedance.« less

Research on subsurface deformed layer in ultra-precision cutting of single crystal copper by focused ion beam etching method

NASA Astrophysics Data System (ADS)

Chen, Y.; Huang, X. J.; Kong, J. X.

2018-03-01

In this paper, the focused ion beam was used to study the subsurface deformed layer of single crystal copper caused by the nanoscale single-point diamond fly cutting, and the possibility of using nanometer ultra-precision cutting to remove the larger deformation layer caused by traditional rough cutting process was explored. The maximum cutting thickness of single-point diamond cutting was about 146 nm, and the surface of the single-crystal copper after cutting was etched and observed by using the focused ion beam method. It was found that the morphology of the near-surface layer and the intermediate layer of the copper material were larger differences: the near-surface of the material was smaller and more compact, and the intermediate material layer of the material was more coarse sparse. The results showed that the traditional precision cutting would residual significant subsurface deformed layer and the thickness was on micron level. Even more, the subsurface deformed layer was obviously removed from about 12μm to 5μm after single-point diamond fly cutting in this paper. This paper proved that the large-scale subsurface deformed layer caused by traditional cutting process could be removed by nanometer ultra-precision cutting. It was of great significance to further establish the method that control of the deformation of weak rigid components by reducing the depth of the subsurface deformed layers.

Regulation of extracellular copper-binding proteins in copper-resistant and copper-sensitive mutants of Vibrio alginolyticus.

PubMed Central

Harwood, V J; Gordon, A S

1994-01-01

Extracellular proteins of wild-type Vibrio alginolyticus were compared with those of copper-resistant and copper-sensitive mutants. One copper-resistant mutant (Cu40B3) constitutively produced an extracellular protein with the same apparent molecular mass (21 kDa) and chromatographic behavior as copper-binding protein (CuBP), a copper-induced supernatant protein which has been implicated in copper detoxification in wild-type V. alginolyticus. Copper-sensitive V. alginolyticus mutants displayed a range of alterations in supernatant protein profiles. CuBP was not detected in supernatants of one copper-sensitive mutant after cultures had been stressed with 50 microM copper. Increased resistance to copper was not induced by preincubation with subinhibitory levels of copper in the wild type or in the copper-resistant mutant Cu40B3. Copper-resistant mutants maintained the ability to grow on copper-amended agar after 10 or more subcultures on nonselective agar, demonstrating the stability of the phenotype. A derivative of Cu40B3 with wild-type sensitivity to copper which no longer constitutively expressed CuBP was isolated. The simultaneous loss of both constitutive CuBP production and copper resistance in Cu40B3 indicates that constitutive CuBP production is necessary for copper resistance in this mutant. These data support the hypothesis that the extracellular, ca. 20-kDa protein(s) of V. alginolyticus is an important factor in survival and growth of the organism at elevated copper concentrations. The range of phenotypes observed in copper-resistant and copper-sensitive V. alginolyticus indicate that altered sensitivity to copper was mediated by a variety of physiological changes. Images PMID:8031076

Bone cell-materials interactions and Ni ion release of anodized equiatomic NiTi alloy.

PubMed

Bernard, Sheldon A; Balla, Vamsi Krishna; Davies, Neal M; Bose, Susmita; Bandyopadhyay, Amit

2011-04-01

A laser processed NiTi alloy was anodized for different times in H(2)SO(4) electrolyte with varying pH to create biocompatible surfaces with low Ni ion release as well as bioactive surfaces to enhance biocompatibility and bone cell-material interactions. The anodized surfaces were assessed for their in vitro cell-material interactions using human fetal osteoblast (hFOB) cells for 3, 7 and 11 days, and Ni ion release up to 8 weeks in simulated body fluids. The results were correlated with the surface morphologies of anodized surfaces characterized using field-emission scanning electron microscopy (FESEM). The results show that anodization creates a surface with nano/micro-roughness depending on the anodization conditions. The hydrophilicity of the NiTi surface was found to improve after anodization, as shown by the lower contact angles in cell medium, which dropped from 32° to <5°. The improved wettability of anodized surfaces is further corroborated by their high surface energy, comparable with that of commercially pure Ti. Relatively high surface energies, especially the polar component, and nano/micro surface features of anodized surfaces significantly increased the number of living cells and their adherence and growth on these surfaces. Finally, a significant drop in Ni ion release from 268±11 to 136±15 ppb was observed for NiTi surfaces after anodization. This work indicates that anodization of a NiTi alloy has a positive influence on the surface energy and surface morphology, which in turn improves bone cell-material interactions and reduces Ni ion release in vitro. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Putting copper into action: copper-impregnated products with potent biocidal activities.

PubMed

Borkow, Gadi; Gabbay, Jeffrey

2004-11-01

Copper ions, either alone or in copper complexes, have been used for centuries to disinfect liquids, solids, and human tissue. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and antibacterial and antifouling agent. Copper also displays potent antiviral activity. We hypothesized that introducing copper into clothing, bedding, and other articles would provide them with biocidal properties. A durable platform technology has been developed that introduces copper into cotton fibers, latex, and other polymeric materials. This study demonstrates the broad-spectrum antimicrobial (antibacterial, antiviral, antifungal) and antimite activities of copper-impregnated fibers and polyester products. This technology enabled the production of antiviral gloves and filters (which deactivate HIV-1 and other viruses), antibacterial self-sterilizing fabrics (which kill antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci), antifungal socks (which alleviate symptoms of athlete's foot), and anti-dust mite mattress covers (which reduce mite-related allergies). These products did not have skin-sensitizing properties, as determined by guine pig maximization and rabbit skin irritation tests. Our study demonstrates the potential use of copper in new applications. These applications address medical issues of the greatest importance, such as viral transmissions; nosocomial, or healthcare-associated, infections; and the spread of antibiotic-resistant bacteria.

Preferential colonization and release of Legionella pneumophila from mature drinking water biofilms grown on copper versus unplasticized polyvinylchloride coupons

EPA Science Inventory

Legionella persistence and amplification in premise drinking water systems is a known contributor to legionellosis outbreaks, especially in the presence of suitable eukaryotic hosts. Here we examined Legionella pneumophila behavior within drinking water biofilms grown on copper ...

EFFECTS OF COPPER ON COMMUNITY, FUNCTIONAL, AND BEHAVIORAL ENDPOINTS IN AN ARTIFICIAL STREAM STUDY

EPA Science Inventory

A study of the effects of copper on biota and behavioral endpoints was carried out at the U.S. EPA's Experimental Stream Facility (ESF), Milford OH. The objective of the study was to identify relationships between structural (macrobenthos and periphyton indices), functional (inte...

The Impact of Hexametaphosphate, Orthophosphate, and Temperature on Copper Corrosion and Release

EPA Science Inventory

Excessive corrosion of copper plumbing can lead to elevated copper levels at consumer’s tap or pinhole leaks. Corrosion control solutions include pH adjustment or phosphate addition. Orthophosphate has been shown to reduce copper levels in some cases while the role of polyphosp...

Dental glass-reinforced composite for caries inhibition: Calcium phosphate ion release and mechanical properties

PubMed Central

Xu, Hockin H. K.; Moreau, Jennifer L.

2010-01-01

The two main challenges facing dental composite restorations are secondary caries and bulk fracture. Previous studies developed whisker-reinforced Ca-PO4 composites that were relatively opaque. The objective of this study was to develop an esthetic glass particle-reinforced, photo-cured calcium phosphate composite. Tetracalcium phosphate (TTCP) particles were incorporated into a resin for Ca and PO4 release, while glass particles provided reinforcement. Ion release and mechanical properties were measured after immersion in solutions with pH of 7, 5.5, and 4. For the composite containing 40% mass fraction of TTCP, incorporating glass fillers increased the strength (p < 0.05). Flexural strength (mean ± sd; n = 6) at 30% glass was (99 ± 18) MPa, higher than (54 ± 20) MPa at 0% glass (p < 0.05). Elastic modulus was 11 GPa at 30% glass, compared to 2 GPa without glass. At 28 d, the released Ca ion concentration was (4.61 ± 0.18) mmol/L at pH of 4, much higher than (1.14 ± 0.07) at pH of 5.5, and (0.27 ± 0.01) at pH of 7 (p < 0.05). PO4 release was also dramatically increased at cariogenic, acidic pH. The TTCP-glass composite had strength 2-3 fold that of a resin-modified glass ionomer control. In conclusion, the photo-cured TTCP-glass composite was “smart” and substantially increased the Ca and PO4 release when the pH was reduced from neutral to a cariogenic pH of 4, when these ions are most needed to inhibit tooth caries. Its mechanical properties were significantly higher than previous Ca, PO4 and fluoride releasing restoratives. Hence, the photo-cured TTCP-glass composite may have potential to provide the necessary combination of load-bearing and caries-inhibiting capabilities. PMID:19810118

The Effect of Some Key Changes in the Chemistry of Water in Relation to Copper and Brass Corrosion Control

NASA Astrophysics Data System (ADS)

Gorovei, M. C.; Benea, L.

2018-06-01

Corrosion means the degradation of the metals or their alloys, under the action of chemical or electrochemical agents from the environment. The complex corrosion phenomenon has a destructive action, generating undesirable economic consequences: metals and labor losses, appreciable reduction in the lifetime of various metal constructions, insecurity in the operation of industrial machinery. Under the current conditions of accelerated growth in the production of material goods, one of the most important issues is the economy of raw materials and materials, energy and labor force. Copper, having a purity of over 99%, is used in the manufacture of gas and water pipes, roofing materials, utensils and ornamental objects. Brass is used in the manufacture of flexible tubes, pipes, coils, cartridges, various electrochemical parts, jewelry, etc. The aim of this research work was to evaluate the corrosion resistance of copper and brass in various solutions: with different chloride ions as 35 g/L NaCl, waste water and tap water. The corrosion behavior of copper and brass was analyzed by electrochemical methods, such as: open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Pure copper exhibits more noble potential values than its alloy (brass), according to the evolution of free potential in all tested solutions. After performing the electrochemical assays, ex-situ investigations, by optical microscopy, were made and the results confirm that the chloride ions affect the corrosion behavior of copper and brass. Corrosion of materials is a very important process to consider when choosing a material that has to operate in a specific environment.

Surface ligand controls silver ion release of nanosilver and its antibacterial activity against Escherichia coli.

PubMed

Long, Yan-Min; Hu, Li-Gang; Yan, Xue-Ting; Zhao, Xing-Chen; Zhou, Qun-Fang; Cai, Yong; Jiang, Gui-Bin

2017-01-01

Understanding the mechanism of nanosilver-dependent antibacterial activity against microorganisms helps optimize the design and usage of the related nanomaterials. In this study, we prepared four kinds of 10 nm-sized silver nanoparticles (AgNPs) with dictated surface chemistry by capping different ligands, including citrate, mercaptopropionic acid, mercaptohexanoic acid, and mercaptopropionic sulfonic acid. Their surface-dependent chemistry and antibacterial activities were investigated. Owing to the weak bond to surface Ag, short carbon chain, and low silver ion attraction, citrate-coated AgNPs caused the highest silver ion release and the strongest antibacterial activity against Escherichia coli , when compared to the other tested AgNPs. The study on the underlying antibacterial mechanisms indicated that cellular membrane uptake of Ag, NAD + /NADH ratio increase, and intracellular reactive oxygen species (ROS) generation were significantly induced in both AgNP and silver ion exposure groups. The released silver ions from AgNPs inside cells through a Trojan-horse-type mechanism were suggested to interact with respiratory chain proteins on the membrane, interrupt intracellular O 2 reduction, and induce ROS production. The further oxidative damages of lipid peroxidation and membrane breakdown caused the lethal effect on E. coli . Altogether, this study demonstrated that AgNPs exerted antibacterial activity through the release of silver ions and the subsequent induction of intracellular ROS generation by interacting with the cell membrane. The findings are helpful in guiding the controllable synthesis through the regulation of surface coating for medical care purpose.

Biodynamics of copper oxide nanoparticles and copper ions in an oligochaete - Part II: Subcellular distribution following sediment exposure

USGS Publications Warehouse

Thit, Amalie; Ramskov, Tina; Croteau, Marie-Noele; Selck, Henriette

2016-01-01

The use and likely incidental release of metal nanoparticles (NPs) is steadily increasing. Despite the increasing amount of published literature on metal NP toxicity in the aquatic environment, very little is known about the biological fate of NPs after sediment exposures. Here, we compare the bioavailability and subcellular distribution of copper oxide (CuO) NPs and aqueous Cu (Cu-Aq) in the sediment-dwelling worm Lumbriculus variegatus. Ten days (d) sediment exposure resulted in marginal Cu bioaccumulation in L. variegatus for both forms of Cu. Bioaccumulation was detected because isotopically enriched 65Cu was used as a tracer. Neither burrowing behavior or survival was affected by the exposure. Once incorporated into tissue, Cu loss was negligible over 10 d of elimination in clean sediment (Cu elimination rate constants were not different from zero). With the exception of day 10, differences in bioaccumulation and subcellular distribution between Cu forms were either not detectable or marginal. After 10 d of exposure to Cu-Aq, the accumulated Cu was primarily partitioned in the subcellular fraction containing metallothionein-like proteins (MTLP, ≈40%) and cellular debris (CD, ≈30%). Cu concentrations in these fractions were significantly higher than in controls. For worms exposed to CuO NPs for 10 d, most of the accumulated Cu was partitioned in the CD fraction (≈40%), which was the only subcellular fraction where the Cu concentration was significantly higher than for the control group. Our results indicate that L. variegatus handle the two Cu forms differently. However, longer-term exposures are suggested in order to clearly highlight differences in the subcellular distribution of these two Cu forms.

The effects of copper proximity on oxalate production in Fibroporia radiculosa

Treesearch

Katie M. Jenkins; Carol A. Clausen; Frederick Green III

2014-01-01

Copper remains a key component used in wood preservatives available today. However, the observed tolerance of several critical wood rotting organisms continues to be problematic. Tolerance to copper has been linked to the production and accumulation of oxalate, which precipitates copper into insoluble copper-oxalate crystals, thus inactivating copper ions. The purpose...

Mechanisms of Contact-Mediated Killing of Yeast Cells on Dry Metallic Copper Surfaces▿

PubMed Central

Quaranta, Davide; Krans, Travis; Santo, Christophe Espírito; Elowsky, Christian G.; Domaille, Dylan W.; Chang, Christopher J.; Grass, Gregor

2011-01-01

Surfaces made of copper or its alloys have strong antimicrobial properties against a wide variety of microorganisms. However, the molecular mode of action responsible for the antimicrobial efficacy of metallic copper is not known. Here, we show that dry copper surfaces inactivate Candida albicans and Saccharomyces cerevisiae within minutes in a process called contact-mediated killing. Cellular copper ion homeostasis systems influenced the kinetics of contact-mediated killing in both organisms. Deregulated copper ion uptake through a hyperactive S. cerevisiae Ctr1p (ScCtr1p) copper uptake transporter in Saccharomyces resulted in faster inactivation of mutant cells than of wild-type cells. Similarly, lack of the C. albicans Crp1p (CaCrp1p) copper-efflux P-type ATPase or the metallothionein CaCup1p caused more-rapid killing of Candida mutant cells than of wild-type cells. Candida and Saccharomyces took up large quantities of copper ions as soon as they were in contact with copper surfaces, as indicated by inductively coupled plasma mass spectroscopy (ICP-MS) analysis and by the intracellular copper ion-reporting dye coppersensor-1. Exposure to metallic copper did not cause lethality through genotoxicity, deleterious action on a cell's genetic material, as indicated by a mutation assay with Saccharomyces. Instead, toxicity mediated by metallic copper surfaces targeted membranes in both yeast species. With the use of Live/Dead staining, onset of rapid and extensive cytoplasmic membrane damage was observed in cells from copper surfaces. Fluorescence microscopy using the indicator dye DiSBaC2(3) indicated that cell membranes were depolarized. Also, during contact-mediated killing, vacuoles first became enlarged and then disappeared from the cells. Lastly, in metallic copper-stressed yeasts, oxidative stress in the cytoplasm and in mitochondria was elevated. PMID:21097600

Sustained release of antibiotic complexed by multivalent ion: in vitro and in vivo study for the treatment of peritonitis.

PubMed

Na, Seung Yeon; Oh, Se Heang; Kim, Tae Ho; Yoon, Jin A; Lee, In Soo; Lee, Jin Ho

2014-12-10

The main aims of this study are (i) the development of an antibiotic complexed with multivalent ion, which can allow sustained release of the antibiotic without any additional matrix or difficult process and (ii) the feasibility study of the ion-complexed antibiotic as a therapeutic technique for peritonitis treatment. An ion-complexed antibiotic is prepared by simple mixing of two aqueous solutions containing an ionized (water-soluble) drug (tetracycline) and a multivalent counter ionic compound. The ion-complexed antibiotic shows a continuous release of the antibiotic up to 21 days, and thus prolonged anti-bacterial effect by gradual ionic exchange between the multivalent ions in the complex and same-charged monovalent ions in surrounding medium. From the in vivo animal study using a cecum perforated peritonitis mouse model, the ion-complexed antibiotic group shows sufficient anti-bacterial effect and thus effectively treat the peritonitis because of the extermination of the contaminated enteric bacteria in the peritoneum during wound healing of injury cecum (by the sustained release of antibiotic from the ion complex). These results suggest that the ion-complexed antibiotic system may be promising for the effective treatment of the peritonitis caused by frequent gastrointestinal defect in clinical fields. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of trace labile copper in environmental waters by magnetic nanoparticle solid phase extraction and high-performance chelation ion chromatography.

PubMed

Wei, Z; Sandron, S; Townsend, A T; Nesterenko, P N; Paull, B

2015-04-01

Cobalt magnetic nanoparticles surface functionalised with iminodiacetic acid were evaluated as a nano-particulate solid phase extraction absorbent for copper ions (Cu(2+)) from environmental water samples. Using an external magnetic field, the collector nanoparticles could be separated from the aqueous phase, and adsorbed ions simply decomplexed using dilute HNO3. Effects of pH, buffer concentration, sample and sorbent volume, extraction equilibrium time, and interfering ion concentration on extraction efficiency were investigated. Optimal conditions were then applied to the extraction of Cu(2+) ions from natural water samples, prior to their quantitation using high-performance chelation ion chromatography. The limits of detection (LOD) of the combined extraction and chromatographic method were ~0.1 ng ml(-1), based upon a 100-fold preconcentration factor (chromatographic performance; LOD=9.2 ng ml(-1) Cu(2+)), analytical linear range from 20 to 5000 ng mL(-1), and relative standard deviations=4.9% (c=1000 ng ml(-1), n=7). Accuracy and precision of the combined approach was verified using a certified reference standard estuarine water sample (SLEW-2) and comparison of sample determinations with sector field inductively coupled plasma mass spectrometry. Recoveries from the addition of Cu(2+) to impacted estuarine and rain water samples were 103.5% and 108.5%, respectively. Coastal seawater samples, both with and without prior UV irradiation and dissolved organic matter removal were also investigated using the new methodology. The effect of DOM concentration on copper availability was demonstrated. Copyright © 2015. Published by Elsevier B.V.

Biosorption of copper ions from aqueous solution using rape straw powders: Optimization, equilibrium and kinetic studies.

PubMed

Liu, Xin; Chen, Zhao-Qiong; Han, Bin; Su, Chun-Li; Han, Qin; Chen, Wei-Zhong

2018-04-15

In this paper, the adsorption behaviors of Cu(II) from the aqueous solution using rape straw powders were studied. The effects of initial Cu(II) concentration, pH range and absorbent dosage on the adsorption efficiency of Cu(II) by rape straw powder were investigated by Box-Behnken Design based on response surface methodology. The values of coefficient constant of the nonlinear models were 0.9997, 0.9984 and 0.9944 for removal Cu(II) from aqueous solution using rape straw shell, seed pods and straw pith core, respectively, which could navigate the design space for various factors on effects of biosorption Cu(II) from aqueous solution. The various factors of pH and biosorbents dosage were the key factors that affecting the removal efficiency of Cu(II) from aqueous solution. The biosorption equilibrium data presented its favorable monolayer adsorption Cu(II) onto shell, seed pods and straw pith core, respectively. The pseudo-second order kinetic model was the proper approach to determine the adsorption kinetics. The biosorption of Cu(II) onto surfaces of rape straw powders were confirmed and ion-exchanged in the adsorption process by energy dispersive spectrometer. The critical groups, -OH, -CH, -NH 3 + , -CH 3 , -NH and -C-O, exhibited by the infrared spectra results, changed to suggest that these groups played critical roles, especially -CH 3 in the adsorption of copper ions onto rape straw powders. The study provided evidences that rape straw powders can be used for removing Cu(II) from aqueous water. Copyright © 2017 Elsevier Inc. All rights reserved.

Diffusion paths formation for Cu + ions in superionic Cu 6PS 5I single crystals studied in terms of structural phase transition

NASA Astrophysics Data System (ADS)

Gągor, A.; Pietraszko, A.; Kaynts, D.

2005-11-01

In order to understand the structural transformations leading to high ionic conductivity of Cu + ions in Cu 6PS 5I argyrodite compound, the detailed structure analysis based on single-crystal X-ray diffraction has been performed. Below the phase transition at T=(144-169) K Cu 6PS 5I belongs to monoclinic, ferroelastic phase (space group Cc) with ordered copper sublattice. Above Tc delocalization of copper ions begins and crystal changes the symmetry to cubic superstructure with space group F-43 c ( a'=19.528 Å, z=32). Finally, above T1=274 K increasing disordering of the Cu + ions heightens the symmetry to F-43 m ( a=9.794 Å, z=4). In this work, the final structural model of two cubic phases is presented including the detailed temperature evolution of positions and site occupation factors of copper ions ( R1=0.0397 for F-43 c phase, and 0.0245 for F-43 m phase). Possible diffusion paths for the copper ions are represented by means of the atomic displacement factors and split model. The structural results coincide well with the previously reported non-Arrhenius behavior of conductivity and indicate significant change in conduction mechanism.

Treatment of model and galvanic waste solutions of copper(II) ions using a lignin/inorganic oxide hybrid as an effective sorbent.

PubMed

Ciesielczyk, Filip; Bartczak, Przemysław; Klapiszewski, Łukasz; Jesionowski, Teofil

2017-04-15

A study was made concerning the removal of copper(II) ions from model and galvanic waste solutions using a new sorption material consisting of lignin in combination with an inorganic oxide system. Specific physicochemical properties of the material resulted from combining the activity of the functional groups present in the structure of lignin with the high surface area of the synthesized oxide system (585m 2 /g). Analysis of the porous structure parameters, particle size and morphology, elemental composition and characteristic functional groups confirmed the effective synthesis of the new type of sorbent. A key element of the study was a series of tests of adsorption of copper(II) ions from model solutions. It was determined how the efficiency of the adsorption process was affected by the process time, mass of sorbent, concentration of adsorbate, pH and temperature. Potential regeneration of adsorbent, which provides the possibility of its reusing and recovering the adsorbed copper, was also analyzed. The sorption capacity of the material was measured (83.98mg/g), and the entire process was described using appropriate kinetic models. The results were applied to the design of a further series of adsorption tests, carried out on solutions of real sewage from a galvanizing plant. Copyright © 2017 Elsevier B.V. All rights reserved.

Chitosan/halloysite beads fabricated by ultrasonic-assisted extrusion-dripping and a case study application for copper ion removal.

PubMed

Choo, Cheng Keong; Kong, Xin Ying; Goh, Tze Lim; Ngoh, Gek Cheng; Horri, Bahman Amini; Salamatinia, Babak

2016-03-15

Development of new materials for different applications especially as bio-composites has received great attention. This study concentrates on development of a biopolymer based on chitosan (CT) and halloysite nanotubes (HNT) and evaluates the copper removal intake as a potential application of this bio-composite. In this study, CT/HNT beads were prepared by ultrasonic-assisted extrusion-dripping method for the first time. Two sources of HNTs (i.e. Dragonite and Matauri Bay) were added into a chitosan solution (2wt.%) at various loading fractions (25, 50, 75wt.%). The effect of ultrasound as a mixing device was also studied by varying the amplitude at constant frequency of 25%, 50% and 75%. Characteristics and physical properties of the prepared CT/HNT beads were also analyzed by SEM, FTIR, TGA and BET the results show that introducing HNT to chitosan increases the adsorption capacity toward copper ions; however HNT loading fraction above 50wt.% resulted in a decrease in adsorption capacity attributed to limited accessibility of the amino groups. The adsorption capacity of the CT/HNT beads prepared from Dragonite source had a larger adsorption capacity of 14.2mg/g as compared to that of Matauri Bay, 10.55mg/g. It was observed that the adsorption capacity of the beads toward copper ions decreased when the loading fraction of HNT is increased at constant ultrasound amplitude. The result of this study helps to understand the links between the characteristics and adsorption abilities of CT/HNT beads. Copyright © 2015 Elsevier Ltd. All rights reserved.

Copper: Its Environmental Impacts. AIO Red Paper #22.

ERIC Educational Resources Information Center

Boutis, Elizabeth; Jantzen, Jonathan Landis, Ed.

Although copper is a widespread and useful metal, the process of mining and refining copper can have severe detrimental impacts on humans, plants, and animals. The most serious impacts from copper production are the release of sulphur dioxide and other air pollutants and the poisoning of water supplies. These impacts occur in both the mining and…

Critical review: Copper runoff from outdoor copper surfaces at atmospheric conditions.

PubMed

Hedberg, Yolanda S; Hedberg, Jonas F; Herting, Gunilla; Goidanich, Sara; Odnevall Wallinder, Inger

2014-01-01

This review on copper runoff dispersed from unsheltered naturally patinated copper used for roofing and facades summarizes and discusses influencing factors, available literature, and predictive models, and the importance of fate and speciation for environmental risk assessment. Copper runoff from outdoor surfaces is predominantly governed by electrochemical and chemical reactions and is highly dependent on given exposure conditions (size, inclination, geometry, degree of sheltering, and orientation), surface parameters (age, patina composition, and thickness), and site-specific environmental conditions (gaseous pollutants, chlorides, rainfall characteristics (amount, intensity, pH), wind direction, temperature, time of wetness, season). The corrosion rate cannot be used to assess the runoff rate. The extent of released copper varies largely between different rain events and is related to dry and wet periods, dry deposition prior to the rain event and prevailing rain and patina characteristics. Interpretation and use of copper runoff data for environmental risk assessment and management need therefore to consider site-specific factors and focus on average data of long-term studies (several years). Risk assessments require furthermore that changes in copper speciation, bioavailability aspects, and potential irreversible retention on solid surfaces are considered, factors that determine the environmental fate of copper runoff from outdoor surfaces.

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract.

PubMed

DeAlba-Montero, I; Guajardo-Pacheco, Jesús; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene; Loredo-Becerra, G M; Martínez-Castañón, Gabriel-Alejandro; Ruiz, Facundo; Compeán Jasso, M E

2017-01-01

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli , Staphylococcus aureus , and Enterococcus faecalis . These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis . Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used.

Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract

PubMed Central

DeAlba-Montero, I.; Morales-Sánchez, Elpidio; Araujo-Martínez, Rene

2017-01-01

This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates over E. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used. PMID:28286459

Copper cladding on polymer surfaces by ionization-assisted deposition

NASA Astrophysics Data System (ADS)

Kohno, Tomoki; Tanaka, Kuniaki; Usui, Hiroaki

2018-03-01

Copper thin films were prepared on poly(ethylene terephthalate) (PET) and polyimide (PI) substrates by an ionization-assisted vapor deposition method. The films had a polycrystalline structure, and their crystallite size decreased with increasing ion acceleration voltage V a. Ion acceleration was effective in reducing the surface roughness of the films. Cross-sectional transmission electron microscopy revealed that the copper/polymer interface showed increased corrugation with increasing V a. The increase in V a also induced the chemical modification of polymer chains of the PET substrate, but the PI substrate underwent smaller modification after ion bombardment. Most importantly, the adhesion strength between the copper film and the PET substrate increased with increasing V a. It was concluded that ionization-assisted deposition is a promising technique for preparing metal clad layers on flexible polymer substrates.

Biochemical characterization of P-type copper ATPases

PubMed Central

Inesi, Giuseppe; Pilankatta, Rajendra; Tadini-Buoninsegni, Francesco

2014-01-01

Copper ATPases, in analogy with other members of the P-ATPase superfamily, contain a catalytic headpiece including an aspartate residue reacting with ATP to form a phosphoenzyme intermediate, and transmembrane helices containing cation-binding sites [TMBS (transmembrane metal-binding sites)] for catalytic activation and cation translocation. Following phosphoenzyme formation by utilization of ATP, bound copper undergoes displacement from the TMBS to the lumenal membrane surface, with no H+ exchange. Although PII-type ATPases sustain active transport of alkali/alkali-earth ions (i.e. Na+, Ca2+) against electrochemical gradients across defined membranes, PIB-type ATPases transfer transition metal ions (i.e. Cu+) from delivery to acceptor proteins and, prominently in mammalian cells, undergo trafficking from/to various membrane compartments. A specific component of copper ATPases is the NMBD (N-terminal metal-binding domain), containing up to six copper-binding sites in mammalian (ATP7A and ATP7B) enzymes. Copper occupancy of NMBD sites and interaction with the ATPase headpiece are required for catalytic activation. Furthermore, in the presence of copper, the NMBD allows interaction with protein kinase D, yielding phosphorylation of serine residues, ATP7B trafficking and protection from proteasome degradation. A specific feature of ATP7A is glycosylation and stabilization on plasma membranes. Cisplatin, a platinum-containing anti-cancer drug, binds to copper sites of ATP7A and ATP7B, and undergoes vectorial displacement in analogy with copper. PMID:25242165

Crystal structures of copper(II) chloride, copper(II) bromide, and copper(II) nitrate complexes with pyridine-2-carbaldehyde thiosemicarbazone

NASA Astrophysics Data System (ADS)

Chumakov, Yu. M.; Tsapkov, V. I.; Jeanneau, E.; Bairac, N. N.; Bocelli, G.; Poirier, D.; Roy, J.; Gulea, A. P.

2008-09-01

The crystal structures of chloro-(2-formylpyridinethiosemicarbazono)copper dimethyl sulfoxide solvate ( I), bromo-(2-formylpyridinethiosemicarbazono)copper ( II), and (2-formylpyridinethiosemicarbazono)copper(II) nitrate dimethyl sulfoxide solvate ( III) are determined using X-ray diffraction. In the crystals, complexes I and II form centrosymmetric dimers in which the thiosemicarbazone sulfur atom serves as a bridge and occupies the fifth coordination site of the copper atom of the neighboring complex related to the initial complex through the center of symmetry. In both cases, the coordination polyhedron of the complexing ion is a distorted tetragonal bipyramid. Complex III in the crystal structure forms polymer chains in which the copper atom of one complex forms the coordination bond with the thicarbamide nitrogen atom of the neighboring complex. In this structure, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid. It is established that complexes I III at a concentration of 10-5 mol/l selectively inhibit the growth of 60 to 90 percent of the cancer tumor cells of the human myeloid leukemia (HL-60).

Synthesis, spectroscopic and thermal studies of the copper(II) aspartame chloride complex

NASA Astrophysics Data System (ADS)

Çakır, S.; Coşkun, E.; Naumov, P.; Biçer, E.; Bulut, İ.; İçbudak, H.; Çakır, O.

2002-08-01

Aspartame adduct of copper(II) chloride Cu(Asp) 2Cl 2·2H 2O (Asp=aspartame) is synthesized and characterized by elemental analysis, FT IR, UV/vis, ESR spectroscopies, TG, DTG, DTA measurements and molecular mechanics calculations. Aqueous solution of the green solid absorbs strongly at 774 and 367 nm. According to the FT IR spectra, the aspartame moiety coordinates to the copper(II) ion via its carboxylate ends, whereas the ammonium terminal groups give rise to hydrogen bonding network with the water, the chloride ions or neighboring carboxylate groups. The results suggest tetragonally distorted octahedral environment of the copper ions.

Constitutive Behavior and Processing Map of T2 Pure Copper Deformed from 293 to 1073 K

NASA Astrophysics Data System (ADS)

Liu, Ying; Xiong, Wei; Yang, Qing; Zeng, Ji-Wei; Zhu, Wen; Sunkulp, Goel

2018-02-01

The deformation behavior of T2 pure copper compressed from 293 to 1073 K with strain rates from 0.01 to 10 s-1 was investigated. The constitutive equations were established by the Arrhenius constitutive model, which can be expressed as a piecewise function of temperature with two sections, in the ranges 293-723 K and 723-1073 K. The processing maps were established according to the dynamic material model for strains of 0.2, 0.4, 0.6, and 0.8, and the optimal processing parameters of T2 copper were determined accordingly. In order to obtain a better understanding of the deformation behavior, the microstructures of the compressed samples were studied by electron back-scattered diffraction. The grains tend to be more refined with decreases in temperature and increases in strain rate.

Copper Regulates Cyclic AMP-Dependent Lipolysis

PubMed Central

Krishnamoorthy, Lakshmi; Cotruvo, Joseph A.; Chan, Jefferson; Kaluarachchi, Harini; Muchenditsi, Abigael; Pendyala, Venkata S.; Jia, Shang; Aron, Allegra T.; Ackerman, Cheri M.; Vander Wal, Mark N.; Guan, Timothy; Smaga, Lukas P.; Farhi, Samouil L.; New, Elizabeth J.; Lutsenko, Svetlana; Chang, Christopher J.

2016-01-01

Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium, and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining the body's weight and energy stores. Utilizing a murine model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we demonstrate that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue within a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype. PMID:27272565

Rate and Regulation of Copper Transport by Human Copper Transporter 1 (hCTR1)*

PubMed Central

Maryon, Edward B.; Molloy, Shannon A.; Ivy, Kristin; Yu, Huijun; Kaplan, Jack H.

2013-01-01

Human copper transporter 1 (hCTR1) is a homotrimer of a 190-amino acid monomer having three transmembrane domains believed to form a pore for copper permeation through the plasma membrane. The hCTR1-mediated copper transport mechanism is not well understood, nor has any measurement been made of the rate at which copper ions are transported by hCTR1. In this study, we estimated the rate of copper transport by the hCTR1 trimer in cultured cells using 64Cu uptake assays and quantification of plasma membrane hCTR1. For endogenous hCTR1, we estimated a turnover number of about 10 ions/trimer/s. When overexpressed in HEK293 cells, a second transmembrane domain mutant of hCTR1 (H139R) had a 3-fold higher Km value and a 4-fold higher turnover number than WT. Truncations of the intracellular C-terminal tail and an AAA substitution of the putative metal-binding HCH C-terminal tripeptide (thought to be required for transport) also exhibited elevated transport rates and Km values when compared with WT hCTR1. Unlike WT hCTR1, H139R and the C-terminal mutants did not undergo regulatory endocytosis in elevated copper. hCTR1 mutants combining methionine substitutions that block transport (M150L,M154L) on the extracellular side of the pore and the high transport H139R or AAA intracellular side mutations exhibited the blocked transport of M150L,M154L, confirming that Cu+ first interacts with the methionines during permeation. Our results show that hCTR1 elements on the intracellular side of the hCTR1 pore, including the carboxyl tail, are not essential for permeation, but serve to regulate the rate of copper entry. PMID:23658018

Systemic levels of metallic ions released from orthodontic mini-implants.

PubMed

de Morais, Liliane Siqueira; Serra, Glaucio Guimarães; Albuquerque Palermo, Elisabete Fernandes; Andrade, Leonardo Rodrigues; Müller, Carlos Alberto; Meyers, Marc André; Elias, Carlos Nelson

2009-04-01

Orthodontic mini-implants are a potential source of metallic ions to the human body because of the corrosion of titanium (Ti) alloy in body fluids. The purpose of this study was to gauge the concentration of Ti, aluminum (Al), and vanadium (V), as a function of time, in the kidneys, livers, and lungs of rabbits that had Ti-6Al-4V alloy orthodontic mini-implants placed in their tibia. Twenty-three New Zealand rabbits were randomly divided into 4 groups: control, 1 week, 4 weeks, and 12 weeks. Four orthodontic mini-implants were placed in the left proximal tibia of 18 rabbits. Five control rabbits had no orthodontic mini-implants. After 1, 4, and 12 weeks, the rabbits were killed, and the selected tissues were extracted and prepared for analysis by graphite furnace atomic absorption spectrophotometry. Low amounts of Ti, Al, and V were detectable in the 1-week, 4-weeks, and 12-weeks groups, confirming that release of these metals from the mini-implants occurs, with diffusion and accumulation in remote organs. Despite the tendency of ion release when using the Ti alloy as orthodontic mini-implants, the amounts of metals detected were significantly below the average intake of these elements through food and drink and did not reach toxic concentrations.

Using Copper Nanoparticle Additive to Improve the Performance of Silicon Anodes in Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Bachand, Gabrielle

In the foreseeable future, global energy demand is expected to rapidly increase as a result of the swelling population and higher standards of living. Current energy generation and transportation methods predominantly involve the combustion of non-renewable fossil fuels, and greenhouse gas emissions from these processes have been shown to contribute to global climate change and to be detrimental to human and environmental health. To satisfy future energy needs and to reduce greenhouse gas emissions, the advancement of renewable energy generation and electric vehicles is important. The proliferation of intermittent renewable energy sources (such as solar and wind) and electric vehicles depends upon reliable, high-capacity energy storage to serve the practical needs of society. The present-day lithium-ion battery offers excellent qualities for this purpose; however, improvements in the capacity and cost-effectiveness of these batteries are needed for further growth. As an anode material, silicon has exceptionally high theoretical capacity and is an earth-abundant, low-cost option. However, silicon also suffers from poor conductivity and long-term stability, prompting many studies to investigate the use of additive materials to mitigate these issues. This thesis focuses on the improvement of silicon anode performance by using a nanoparticulate copper additive to increase material conductivity and an inexpensive, industry-compatible anode fabrication process. Three main fabrication processes were explored using differing materials and heat treatment techniques for comparison. Anodes were tested using CR2032 type coin cells. The final anodes with the most-improved characteristics were fabricated using a high-temperature heating step for the anode material, and an additional batch was formed to test the viability of the copper additive functioning as a full substitute for carbon black, which is the traditional choice of conductive additive for electrode materials. Anodes

Molecular Mediators Governing Iron-Copper Interactions

PubMed Central

Gulec, Sukru; Collins, James F.

2015-01-01

Given their similar physiochemical properties, it is a logical postulate that iron and copper metabolism are intertwined. Indeed, iron-copper interactions were first documented over a century ago, but the homeostatic effects of one on the other has not been elucidated at a molecular level to date. Recent experimental work has, however, begun to provide mechanistic insight into how copper influences iron metabolism. During iron deficiency, elevated copper levels are observed in the intestinal mucosa, liver, and blood. Copper accumulation and/or redistribution within enterocytes may influence iron transport, and high hepatic copper may enhance biosynthesis of a circulating ferroxidase, which potentiates iron release from stores. Moreover, emerging evidence has documented direct effects of copper on the expression and activity of the iron-regulatory hormone hepcidin. This review summarizes current experimental work in this field, with a focus on molecular aspects of iron-copper interplay and how these interactions relate to various disease states. PMID:24995690

Integrated miniature fluorescent probe to leverage the sensing potential of ZnO quantum dots for the detection of copper (II) ions.

PubMed

Ng, Sing Muk; Wong, Derrick Sing Nguong; Phung, Jane Hui Chiun; Chin, Suk Fun; Chua, Hong Siang

2013-11-15

Quantum dots are fluorescent semiconductor nanoparticles that can be utilised for sensing applications. This paper evaluates the ability to leverage their analytical potential using an integrated fluorescent sensing probe that is portable, cost effective and simple to handle. ZnO quantum dots were prepared using the simple sol-gel hydrolysis method at ambient conditions and found to be significantly and specifically quenched by copper (II) ions. This ZnO quantum dots system has been incorporated into an in-house developed miniature fluorescent probe for the detection of copper (II) ions in aqueous medium. The probe was developed using a low power handheld black light as excitation source and three photo-detectors as sensor. The sensing chamber placed between the light source and detectors was made of 4-sided clear quartz windows. The chamber was housed within a dark compartment to avoid stray light interference. The probe was operated using a microcontroller (Arduino Uno Revision 3) that has been programmed with the analytical response and the working algorithm of the electronics. The probe was sourced with a 12 V rechargeable battery pack and the analytical readouts were given directly using a LCD display panel. Analytical optimisations of the ZnO quantum dots system and the probe have been performed and further described. The probe was found to have a linear response range up to 0.45 mM (R(2)=0.9930) towards copper (II) ion with a limit of detection of 7.68×10(-7) M. The probe has high repeatable and reliable performance. Copyright © 2013 Elsevier B.V. All rights reserved.

Encapsulation of anticancer drug copper bis(8-hydroxyquinoline) in hydroxyapatite for pH-sensitive targeted delivery and slow release.

PubMed

Weerasuriya, D R K; Wijesinghe, W P S L; Rajapakse, R M G

2017-02-01

There is a conspicuous progress in increasing anticancer drug delivery through the utilization of nanoparticles (NPs) as drug delivery agents. Hydroxyapatite (HA) gives improved clinical effectiveness of drugs by reducing systemic toxicity and broadening the spectrum of drug delivery since it is biocompatible and it can be targeted towards tumor cells. Herein, investigation of the potential of enhancing controlled drug release of the template model drug, copper bis-(8-hydroxyquinoline), by encapsulating it in hollow hydroxyapatite nano-carriers, is presented. Hydroxyapatite nanoparticles are synthesized by following four different routes to optimize its efficacy of drug loading. Copper bis-(8-hydroxyquinoline) is encapsulated by Method (a) which was effected by stirring the model drug and porous HA NPs in colloidal solution and Method (b) which was done during synthesis of hydroxyapatite nanoparticles in a solution of the model drug. In synthesizing nanoporous HA NPs, calcium carbonate is used as a template to create voids in HA. In each method, Ca/P ratio was ensured to be kept at 1.67:1. Appealing results are reported for the encapsulated product which was prepared by Method (a2). Method (a) was done at three different molar ratios of PO 4 3- :CO 3 2- and best result was obtained for that utilized 2.003:1 molar ratio (Method (a2).). It produced 98.67% of encapsulation efficiency and 2.9522mg/g of drug loading capacity. Release kinetics was studied at a range of pH values; the lower the pH of the medium the higher is the drug release. For instance, when considering the product which exhibited high encapsulation efficiency and high drug loading capacity, at pH3.5 during the first 8h it elicited about 13% of release, at pH5.0 about 8% release while at pH6.0 it was just 2.5%. During the 24-hour span, pH3.5 exhibited about 23.8%, at pH5.0 approximately 9% with an increasing trend of release and at pH6.0 showed a value just above 2.5%. As such, acidity of the cancerous

Interactive Effects of Corrosion, Copper, and Chloramines on Legionella and Mycobacteria in Hot Water Plumbing.

PubMed

Rhoads, William J; Pruden, Amy; Edwards, Marc A

2017-06-20

Complexities associated with drinking water plumbing systems can result in undesirable interactions among plumbing components that undermine engineering controls for opportunistic pathogens (OPs). In this study, we examine the effects of plumbing system materials and two commonly applied disinfectants, copper and chloramines, on water chemistry and the growth of Legionella and mycobacteria across a transect of bench- and pilot-scale hot water experiments carried out with the same municipal water supply. We discovered that copper released from corrosion of plumbing materials can initiate evolution of >1100 times more hydrogen (H 2 ) from water heater sacrificial anode rods than does presence of copper dosed as soluble cupric ions. H 2 is a favorable electron donor for autotrophs and causes fixation of organic carbon that could serve as a nutrient for OPs. Dosed cupric ions acted as a disinfectant in stratified stagnant pipes, inhibiting culturable Legionella and biofilm formation, but promoted Legionella growth in pipes subject to convective mixing. This difference was presumably due to continuous delivery of nutrients to biofilm on the pipes under convective mixing conditions. Chloramines eliminated culturable Legionella and prevented L. pneumophila from recolonizing biofilms, but M. avium gene numbers increased by 0.14-0.76 logs in the bulk water and were unaffected in the biofilm. This study provides practical confirmation of past discrepancies in the literature regarding the variable effects of copper on Legionella growth, and confirms prior reports of trade-offs between Legionella and mycobacteria if chloramines are applied as secondary disinfectant residual.

Release behavior of tanshinone IIA sustained-release pellets based on crack formation theory.

PubMed

Liu, Pan; Li, Jin; Liu, Jianping; Yang, Jikun; Fan, Yongqing

2012-08-01

The objective of this study was to investigate the drug release mechanism and in vivo performance of Tanshinone IIA sustained-release pellets, coated with blends of polyvinyl acetate (PVAc) and poly(vinyl alcohol)-poly(ethylene glycol) (PVA-PEG) graft copolymer. A formulation screening study showed that pellets coated with PVAc-PVA-PEG at a ratio of 70:30 (w/w) succeeded in achieving a 24 h sustained release, irrespective of the coating weight (from 2% to 10%). Both the microscopic observation and mathematical model gave further insight into the underlying release mechanism, indicating that diffusion through water-filled cracks was dominant for the control of drug release. In vivo test showed that the maximum plasma concentration of sustained-release pellets was decreased from 82.13 ± 17.05 to 40.50 ± 11.72 ng mL as that of quick-release pellets. The time of maximum concentration, half time, and mean residence time were all prolonged from 3.80 ± 0.40 to 8.02 ± 0.81 h, 4.28 ± 1.21 to 8.18 ± 2.06 h, and 8.60 ± 1.59 to 17.50 ± 2.78 h, compared with uncoated preparations. A good in vitro-in vivo correlation was characterized by a high coefficient of determination (r = 0.9772). In conclusion, pellets coated with PVAc-PVA-PEG could achieve a satisfactory sustained-release behavior based on crack formation theory. Copyright © 2012 Wiley Periodicals, Inc.

The grinding behavior of ground copper powder for Cu/CNT nanocomposite fabrication by using the dry grinding process with a high-speed planetary ball mill

NASA Astrophysics Data System (ADS)

Choi, Heekyu; Bor, Amgalan; Sakuragi, Shiori; Lee, Jehyun; Lim, Hyung-Tae

2016-01-01

The behavior of ground copper powder for copper-carbon nanotube (copper-CNT) nanocomposite fabrication during high-speed planetary ball milling was investigated because the study of the behavior characteristics of copper powder has recently gained scientific interest. Also, studies of Cu/CNT composites have widely been done due to their useful applications to enhanced, advanced nano materials and components, which would significantly improve the properties of new mechatronics-integrated materials and components. This study varied experimental conditions such as the rotation speed and the grinding time with and without CNTs, and the particle size distribution, median diameter, crystal structure and size, and particle morphology were monitored for a given grinding time. We observed that pure copper powders agglomerated and that the morphology changed with changing rotation speed. The particle agglomerations were observed with maximum experiment conditions (700 rpm, 60 min) in this study of the grinding process for mechanical alloys in the case of pure copper powders because the grinding behavior of Cu/CNT agglomerations was affected by the addition of CNTs. Indeed, the powder morphology and the crystal size of the composite powder could be changed by increasing the grinding time and the rotation speed.

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements.

PubMed

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-13

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter ( n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA ( p < 0.05) while maximum calcium ion release was dependent on Vol of TSC ( p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution ( p < 0.05).

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements

PubMed Central

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-01

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter (n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA (p < 0.05) while maximum calcium ion release was dependent on Vol of TSC (p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution (p < 0.05). PMID:29342837

Copper-Exchanged Zeolite L Traps Oxygen

NASA Technical Reports Server (NTRS)

Sharma, Pramod K.; Seshan, Panchalam K.

1991-01-01

Brief series of simple chemical treatments found to enhance ability of zeolite to remove oxygen from mixture of gases. Thermally stable up to 700 degrees C and has high specific surface area which provides high capacity for adsorption of gases. To increase ability to adsorb oxygen selectively, copper added by ion exchange, and copper-exchanged zeolite reduced with hydrogen. As result, copper dispersed atomically on inner surfaces of zeolite, making it highly reactive to oxygen, even at room temperature. Reactivity to oxygen even greater at higher temperatures.

Porous magnesium loaded with gentamicin sulphate and in vitro release behavior.

PubMed

Li, Qiuyan; Jiang, Guofeng; Wang, Dong; Wang, Huang; Ding, Liang; He, Guo

2016-12-01

Our aim was to develop a biocompatible bone repair material that has the advantage of preventing postoperative infections. Finally, the porous magnesium (p-Mg) loaded with gentamicin sulphate (GS-loaded Mg-G) was fabricated. The GS release behavior of the GS-loaded Mg-G in phosphate buffer saline (PBS) was investigated. The effective release time of GS reached to 14days. In addition, the effects of porosity and pore diameter of p-Mg on the GS release behavior of the GS-loaded Mg-G were studied. In the initial burst release stage, the GS release rate of the GS-loaded Mg-G increased with the increasing porosity or the increasing pore diameter of p-Mg. The GS-loaded Mg-G with larger original pore diameter has higher burst release of GS. Moreover, the in vitro antibacterial test of the GS-loaded Mg-G indicated that this biomaterial has obvious antibacterial effect. This study can provide information for p-Mg loaded with drug(s) as functional bone repair materials with drug-delivery capabilities. Copyright © 2016 Elsevier B.V. All rights reserved.

Biosorption of metal ions from aqueous solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jiaping; Yiacoumi, Sotira

1997-01-01

Copper biosorption from aqueous solutions by calcium alginate is reported in this paper. The experimental section includes potentiometric titrations of biosorbents, batch equilibrium and kinetic studies of copper biosorption, as well as fixed-bed biosorption experiments. The potentiometric titration results show that the surface charge increases with decreasing pH. The biosorption of copper strongly depends on solution pH; the metal ion binding increases from 0 to 90 percent in pH ranging from 1.5 to 5.0. In addition, a decrease in ionic strength results in an increase of copper ion removal. Kinetic studies indicate that mass transfer plays an important role inmore » the biosorption rate. Furthermore, a fixed-bed biosorption experiment shows that calcium alginate has a significant capacity for copper ion removal. The two-pK Basic Stem model successfully represents the surface charge and equilibrium biosorption experimental data. The calculation results demonstrate that the copper removal may result from the binding of free copper and its hydroxide with surface functional groups of the biosorbents.« less

Controlled release behaviors of chitosan/α, β-glycerophosphate thermo-sensitive hydrogels

NASA Astrophysics Data System (ADS)