Copper-releasing, boron-containing bioactive glass-based scaffolds coated with alginate for bone tissue engineering.

PubMed

Erol, M M; Mouriňo, V; Newby, P; Chatzistavrou, X; Roether, J A; Hupa, L; Boccaccini, Aldo R

2012-02-01

The aim of this study was to synthesize and characterize new boron-containing bioactive glass-based scaffolds coated with alginate cross-linked with copper ions. A recently developed bioactive glass powder with nominal composition (wt.%) 65 SiO2, 15 CaO, 18.4 Na2O, 0.1 MgO and 1.5 B2O3 was fabricated as porous scaffolds by the foam replica method. Scaffolds were alginate coated by dipping them in alginate solution. Scanning electron microscopy investigations indicated that the alginate effectively attached on the surface of the three-dimensional scaffolds leading to a homogeneous coating. It was confirmed that the scaffold structure remained amorphous after the sintering process and that the alginate coating improved the scaffold bioactivity and mechanical properties. Copper release studies showed that the alginate-coated scaffolds allowed controlled release of copper ions. The novel copper-releasing composite scaffolds represent promising candidates for bone regeneration. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Contact Killing of Bacteria on Copper Is Suppressed if Bacterial-Metal Contact Is Prevented and Is Induced on Iron by Copper Ions

PubMed Central

Mathews, Salima; Hans, Michael

2013-01-01

Bacteria are rapidly killed on copper surfaces, and copper ions released from the surface have been proposed to play a major role in the killing process. However, it has remained unclear whether contact of the bacteria with the copper surface is also an important factor. Using laser interference lithography, we engineered copper surfaces which were covered with a grid of an inert polymer which prevented contact of the bacteria with the surface. Using Enterococcus hirae as a model organism, we showed that the release of ionic copper from these modified surfaces was not significantly reduced. In contrast, killing of bacteria was strongly attenuated. When E. hirae cells were exposed to a solid iron surface, the loss of cell viability was the same as on glass. However, exposing cells to iron in the presence of 4 mM CuSO4 led to complete killing in 100 min. These experiments suggest that contact killing proceeds by a mechanism whereby the metal-bacterial contact damages the cell envelope, which, in turn, makes the cells susceptible to further damage by copper ions. PMID:23396344

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.

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.

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.

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.

[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.

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.

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.

Copper-zinc superoxide dismutase is activated through a sulfenic acid intermediate at a copper ion entry site.

PubMed

Fetherolf, Morgan M; Boyd, Stefanie D; Taylor, Alexander B; Kim, Hee Jong; Wohlschlegel, James A; Blackburn, Ninian J; Hart, P John; Winge, Dennis R; Winkler, Duane D

2017-07-21

Metallochaperones are a diverse family of trafficking molecules that provide metal ions to protein targets for use as cofactors. The copper chaperone for superoxide dismutase (Ccs1) activates immature copper-zinc superoxide dismutase (Sod1) by delivering copper and facilitating the oxidation of the Sod1 intramolecular disulfide bond. Here, we present structural, spectroscopic, and cell-based data supporting a novel copper-induced mechanism for Sod1 activation. Ccs1 binding exposes an electropositive cavity and proposed "entry site" for copper ion delivery on immature Sod1. Copper-mediated sulfenylation leads to a sulfenic acid intermediate that eventually resolves to form the Sod1 disulfide bond with concomitant release of copper into the Sod1 active site. Sod1 is the predominant disulfide bond-requiring enzyme in the cytoplasm, and this copper-induced mechanism of disulfide bond formation obviates the need for a thiol/disulfide oxidoreductase in that compartment. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Release of Micronized Copper Particles from Pressure ...

EPA Pesticide Factsheets

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 particles. Two common pathways of exposure, leaching during contact with water and transfer during physical contact, were investigated to gage potential human and environmental risk during intended use of the product. Characterization, leaching tests, and wipe tests were conducted on two representative formulations of micronized copper PTL (micronized copper azole or MCA) to quantify the levels of copper present in the treated material and the amount of copper released during use as well as to determine the form (particle or ion) of the copper after it was released. Additionally, an ionized copper pressure treated wood (alkaline copper azole or ACA) was tested for comparison. The characterization showed that copper carbonate is the primary particle form in the MCA treated wood, but other forms are also present, particularly in the MCA-1 formulation, which contained a large amount of organically complexed copper. Microscopy showed that MCA-1 contained particles roughly half the size of MCA-2. The leaching results indicate that mostly (> ~95%) ionic copper is released from the MCA wood and that the particulate copper that was released is attached to cellulose and not free in solution. A sma

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.

Ion release from orthodontic brackets in 3 mouthwashes: an in-vitro study.

PubMed

Danaei, Shahla Momeni; Safavi, Afsaneh; Roeinpeikar, S M Mehdi; Oshagh, Morteza; Iranpour, Shiva; Omidkhoda, Maryam; Omidekhoda, Maryam

2011-06-01

Stainless steel orthodontic brackets can release metal ions into the saliva. Fluoridated mouthwashes are often recommended to orthodontic patients to reduce the risk of white-spot lesions around their brackets. However, little information is available regarding the effect of different mouthwashes in ion release of orthodontic brackets. The purpose of this study was to measure the amount of metal ion release from orthodontic brackets when kept in different mouthwashes. One hundred sixty stainless steel brackets (0.022-in, 3M Unitek, Monrovia, Calif) were divided randomly into 4 equal groups and immersed in Oral B (Procter & Gamble, Weybridge, United Kingdom), chlorhexidine (Shahdaru Labratories, Tehran, Iran), and Persica (Poursina Pharmaceutical Laboratories, Tehran, Iran) mouthwashes and distilled deionized water and incubated at 37°C for 45 days. Nickel, chromium, iron, copper, and manganese released from the orthodontic brackets were measured with an inductively coupled plasma spectrometer. For statistical analysis, 1-way analysis of variance (ANOVA) and the Duncan multiple-range tests were used. The results showed that ion release in deionized water was significantly (P <0.05) higher than in the 3 mouthwashes. Higher ion release was found with chlorhexidine compared with the other 2 mouthwashes. There was no significant difference (P >0.05) in nickel, chromium, iron, and copper ion release in the Oral B and Persica mouthwashes. The level of manganese release was significantly different in all 4 groups. If ion release is a concern, Oral B and Persica mouthwashes might be better options than chlorhexidine for orthodontic patients with stainless steel brackets. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

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.

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.

Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.

PubMed

Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

2015-02-28

Copper ions represent a promising angiogenic agent but are associated with cytotoxicity at elevated concentrations. Phosphate-based glasses (PGs) exhibit adjustable dissolution properties and allow for controlled ion release. This study examined the formation of capillary-like networks by SVEC4-10 endothelial cells (ECs) seeded in a three-dimensional (3D) type I collagen hydrogel matrix mixed with PG particles of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0 and 10 mol%). Copper and total phosphorus release decreased over time and was more sustained in the case of 10% CuO PG. Moreover, increasing the concentration of 10% CuO PG in collagen substantially delayed dissolution along with preferential release of copper. A 3D morphometric characterization method based on confocal laser scanning microscopy image stacks was developed in order to quantify EC network length, connectivity and branching. Network length was initially reduced in a concentration-dependent fashion by 10% CuO PG and, to a lesser extent, by 0% CuO PG, but reached values identical to the non-PG control by day 5 in culture. This reduction was attributed to a PG-mediated decrease in cell metabolic activity while cell proliferation as well as network connectivity and branching were independent of PG content. Gene expression of matrix metalloproteinases (MMP)-1 and -2 was up-regulated by PGs, indicating that MMPs did not play a critical role in network growth. The relationship between ion release and EC morphogenesis in 3D provided in this study is expected to contribute to an ultimately successful pro-angiogenic application of CuO-doped PGs. Copyright © 2015 Elsevier B.V. All rights reserved.

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

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 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.

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).

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-free cements. The difference in the mechanism of protection of dehydratases in prokaryotes and eukaryotes was used as a rationale for explaining the hereby evidenced selectivity in biological response. It presents the basis for the consideration of copper as a dually effective ion when synergized with calcium phosphates: toxic for bacteria and beneficial for the healthy cells. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

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 do not efficiently extract copper from soluble amyloids. We have designed and developed new tetradendate ligands such as 21 and PA1637 based on bis(8-aminoquinolines) that are specific for copper chelation and are able to extract copper(II) from amyloids and then can release copper ion upon reduction with a biological reducing agent. These studies contribute to the understanding of the physicochemical properties of the tetradentate copper ligands compared with bidentate ligands like clioquinol. One of these copper ligands, PA1637, after selection with a nontransgenic mouse model that is able to efficiently monitor the loss of episodic memory, is currently under preclinical development.

Direct ROS scavenging activity of CueP from Salmonella enterica serovar Typhimurium.

PubMed

Yoon, Bo-Young; Yeom, Ji-Hyun; Kim, Jin-Sik; Um, Si-Hyeon; Jo, Inseong; Lee, Kangseok; Kim, Yong-Hak; Ha, Nam-Chul

2014-02-01

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu, Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages.

Angiogenesis in calcium phosphate scaffolds by inorganic copper ion release.

PubMed

Barralet, Jake; Gbureck, Uwe; Habibovic, Pamela; Vorndran, Elke; Gerard, Catherine; Doillon, Charles J

2009-07-01

Angiogenesis in a tissue-engineered device may be induced by incorporating growth factors (e.g., vascular endothelial growth factor [VEGF]), genetically modified cells, and=or vascular cells. It represents an important process during the formation and repair of tissue and is essential for nourishment and supply of reparative and immunological cells. Inorganic angiogenic factors, such as copper ions, are therefore of interest in the fields of regenerative medicine and tissue engineering due to their low cost, higher stability, and potentially greater safety compared with recombinant proteins or genetic engineering approaches. The purpose of this study was to compare tissue responses to 3D printed macroporous bioceramic scaffolds implanted in mice that had been loaded with either VEGF or copper sulfate. These factors were spatially localized at the end of a single macropore some 7 mm from the surface of the scaffold. Controls without angiogenic factors exhibited only poor tissue growth within the blocks; in contrast, low doses of copper sulfate led to the formation of microvessels oriented along the macropore axis. Further, wound tissue ingrowth was particularly sensitive to the quantity of copper sulfate and was enhanced at specific concentrations or in combination with VEGF. The potential to accelerate and guide angiogenesis and wound healing by copper ion release without the expense of inductive protein(s) is highly attractive in the area of tissue-engineered bone and offers significant future potential in the field of regenerative biomaterials.

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.

Susceptibility to corrosion and in vitro biocompatibility of a laser-welded composite orthodontic arch wire.

PubMed

Zhang, Chao; Sun, Xinhua; Zhao, Shuang; Yu, Wenwen; Sun, Daqian

2014-01-01

Composite arch-wire (CoAW) is an arch wire formed by solder connection of nickel titanium shape memory alloy and stainless steel wire. The purpose of the present study was to investigate the biocompatibility of CoAW as an important foundation for its clinical application. The electrochemical corrosion and ion release behavior of CoAW upon immersion in solutions simulating oral cavity conditions were measured to evaluate the corrosion behavior of CoAW. Murine L-929 cells were co-cultured with CoAW extract to evaluate the cytotoxicity of the corrosion products in vitro. Polarization tests indicated that CoAW is resistant to corrosion in the tested artificial saliva (AS)-based solutions (chloric solution, simple AS, fluorinated AS, and protein-containing AS), and the amount of toxic copper ions released after immersion was lower than average daily dietary intake levels. The cytotoxicity experiments demonstrated the in vitro biocompatibility of CoAW. Based on the combined advantages of its base materials CoAW, with its resistance to biocorrosion and in vitro cytocompatibility, is a promising alternative material for use in orthodontic fixation applications.

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

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.

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...

Iron and copper release in drinking-water distribution systems.

PubMed

Shi, Baoyou; Taylor, James S

2007-09-01

A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs). The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes. Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release. The iron release of desalinated water was relatively high because of the water's high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature.

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

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 antimicrobial activity.

Effect of chloride ions on the corrosion behavior of low-alloy steel containing copper and antimony in sulfuric acid solution

NASA Astrophysics Data System (ADS)

Park, Sun-Ah; Kim, Seon-Hong; Yoo, Yun-Ha; Kim, Jung-Gu

2015-05-01

The influence of the addition of HCl on the corrosion behavior of low-alloy steel containing copper and antimony was investigated using electrochemical (potentiodynamic and potentiostatic polarization tests, and electrochemical impedance spectroscopy) and weight loss tests in a 1.6M H2SO4 solution with different concentrations of hydrochloric acid (0.00, 0.08, 0.15 and 0.20 M HCl) at 60 °C. The result showed that the corrosion rate decreased with increasing HCl by the formation of protective layers. SEM, EDS and XPS examinations of the corroded surfaces after the immersion test indicated that the corrosion production layer formed in the solution containing HCl was highly comprised of metallic Cu, Cu chloride and metallic (Fe, Cu, Sb) compounds. The corrosion resistance was improved by the Cu-enriched layer, in which chloride ions are an accelerator for cupric ion reduction during copper deposition. Furthermore, cuprous and antimonious chloride species are complex salts for cuprous ions adsorbed on the surface during copper deposition.

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 antimicrobial activity. Key Words: Contact killing-E. coli-S. cohnii-Antimicrobial copper surfaces-Copper oxide layers-Human health-Planetary protection. Astrobiology 17, 1183-1191.

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

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.

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 antibacterial activity than copper vermiculite against E. coli. With 200 ppm exfoliated copper vermiculite in bacteria suspension (4.68 ppm of metal copper), the reduction of viable bacteria are 99.8% at 1 hour, and >99.9% at 2 hours. With 10 ppm exfoliated copper vermiculite in bacteria dilution (0.234 ppm of copper atoms), the reduction of viable E. coli reached 98.7% at 1 hour, and >95.6% at 2 hours. Molds have the potential to cause health problems, such as allergic reactions, irritations, and mycotoxins, and damage to buildings, historic relics, properties, etc. Since copper has better antifungal property, an initial antifungal activity of copper vermiculite was evaluated in this study. Fat-free milk was used to develop molds in the test samples by saturated samples. Incubated at 36°C for 48 hours, all of the surfaces of untreated control samples, including micron-sized vermiculite, exfoliated vermiculite, bentonite, and kaolin, have been covered by thick mold layers. However, there were no mold showed on copper vermiculite and exfoliated copper vermiculite. Even after the incubation was lasted for 10 days, copper vermiculite and exfoliated copper vermiculite did not show any mold on the surface. These results exhibited copper vermiculite has excellent antifungal activities against mold. Stability of copper ions in copper vermiculite was measured by aqueous leaching process. Copper vermiculite and exfoliated copper vermiculite were put into distilled water in a ratio of 2.0g/100ml, and then implemented leaching processes by continuously shaking (leaching) and statically storing (soaking) for desired periods of time, respectively. According to the analytic result by inductively coupled plasma spectroscopy (ICP), the major metals released were copper, magnesium, iron, silicon, and aluminum. The release rate of copper depends on the environmental conditions. Under the dynamic leaching condition, all the major elements had shown linear leaching rates, and slowly increases along with the leaching time. Copper concentration in 1 hour leached solutions had sufficient concentration to inhibit E. coli in aqueous solution. Lasting for 1 month, 1 gram of copper vermiculite only released 185mug of copper. At this velocity, 11.5 years are required to completely exhaust the copper atoms from copper vermiculite. A soaking process provided a lower release rate than leaching process. Comparably, exfoliated copper vermiculite had lower copper concentration, stronger antimicrobial effect, but faster release rate than copper vermiculite, due to their different structure characteristics. (Abstract shortened by UMI.)

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 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.

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.

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.

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 physicochemical properties of the particles like surface area may be of major relevance. Regarding direct and indirect genotoxicity, especially the high copper content in the cell nucleus derived after cell treatment with CuO NP appears to be decisive.

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 particles as well as differences in physicochemical properties of the particles like surface area may be of major relevance. Regarding direct and indirect genotoxicity, especially the high copper content in the cell nucleus derived after cell treatment with CuO NP appears to be decisive. PMID:24520990

Copper-transporting P-type ATPases use a unique ion-release pathway

PubMed Central

Andersson, Magnus; Mattle, Daniel; Sitsel, Oleg; Nielsen, Anna Marie; White, Stephen H.; Nissen, Poul; Gourdon, Pontus

2014-01-01

Heavy metals in cells are typically regulated by PIB-type ATPases such as the copper transporting Cu+-ATPases. The first crystal structure of a Cu+-ATPase (LpCopA) was trapped in a transition state of dephosphorylation (E2.Pi) and inferred to be occluded. The structure revealed a PIB-specific topology and suggested a copper transport pathway across the membrane. Here we show by molecular dynamics (MD) simulations that extracellular water solvates the transmembrane (TM) domain, indicative of a pathway for Cu+ release. Furthermore, a new LpCopA crystal structure determined at 2.8 Å resolution, trapped in the E2P state (which is associated with extracellular exchange in PII-type ATPases), delineates the same conduit as also further supported by site-directed mutagenesis. The E2P and E2.Pi states therefore appear equivalent and open to the extracellular side, in contrast to PII-type ATPases where the E2.Pi state is occluded. This indicates that Cu+-ATPases couple dephosphorylation differently to the conformational changes associated with ion extrusion. The ion pathway may explain why Menkes’ and Wilson’s disease mutations at the extracellular side impair protein function, and points to an accessible site for novel inhibitors targeting Cu+-ATPases of pathogens. PMID:24317491

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

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.

Structural effects of Cu(II)-coordination in the octapeptide region of the human prion protein.

PubMed

Riihimäki, Eva-Stina; Martínez, José Manuel; Kloo, Lars

2008-05-14

The copper-binding ability of the prion protein is thought to be central to its function. The structural effects of copper coordination in the octapeptide region of the human prion protein have been investigated by molecular dynamics simulations. Simulations were performed with the apo state, in order to investigate the behavior of the region without copper ions, as well as with the octapeptide region in the presence of copper ions. While the structure of the apo state is greatly influenced by the interaction between the rings in the histidine, tryptophan and proline residues, the region shows evidence of highly ordered coordination sites in the presence of copper ions. The position of the tryptophan indole ring is stabilized by cation-pi interactions. Two stable orientations of the indole ring with respect to the equatorial coordination plane of copper were observed, which showed that the indole ring can reside on both sides of the coordination plane. The interaction with the indole ring was found to occur without a mediating axial water molecule.

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

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.

Antimicrobial properties of ternary eutectic aluminum alloys.

PubMed

Hahn, Claudia; Hans, Michael; Hein, Christina; Dennstedt, Anne; Mücklich, Frank; Rettberg, Petra; Hellweg, Christine Elisabeth; Leichert, Lars Ingo; Rensing, Christopher; Moeller, Ralf

2018-06-27

Several Escherichia coli deletion mutants of the Keio collection were selected for analysis to better understand which genes may play a key role in copper or silver homeostasis. Each of the selected E. coli mutants had a deletion of a single gene predicted to encode proteins for homologous recombination or contained functions directly linked to copper or silver transport or transformation. The survival of these strains on pure copper surfaces, stainless steel, and alloys of aluminum, copper and/or silver was investigated. When exposed to pure copper surfaces, E. coli ΔcueO was the most sensitive, whereas E. coli ΔcopA was the most resistant amongst the different strains tested. However, we observed a different trend in sensitivities in E. coli strains upon exposure to alloys of the system Al-Ag-Cu. While minor antimicrobial effects were detected after exposure of E. coli ΔcopA and E. coli ΔrecA to Al-Ag alloys, no effect was detected after exposure to Al-Cu alloys. The release of copper ions and cell-associated copper ion concentrations were determined for E. coli ΔcopA and the wild-type E. coli after exposure to pure copper surfaces. Altogether, compared to binary alloys, ternary eutectic alloys (Al-Ag-Cu) had the highest antimicrobial effect and thus, warrant further investigation.

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

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.

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.

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 ...

Rolling contact fatigue behavior of Cu and TiN coatings on bearing steel substrates

NASA Technical Reports Server (NTRS)

Hochman, R. F.; Erdemir, A.; Dolan, F. J.; Thom, R. L.

1985-01-01

The resistance of copper and TiN coatings on various bearing substrates to high-load rolling contact fatigue (RCF) is investigated. Special attention is given to the lubricating characteristics of copper deposited by ion plating, and the wear resistant characteristics of TiN deposited by ion plating and magnetron sputtering techniques. RCF samples of 440C and AMS 5749 bearing steels were coated. Sputter deposited and ion plated films were on the RCF samples in a range of thickness from about 2000 A to 2 microns. Results showed a marked improvement of the RCF for pure copper tested on 440C, but a degradation for copper on AMS 5749. It is also found that the 2000 A TiN films behave favorably on the 440C and AMS 5749 bearing steels at RCF stress levels of 786 ksi. Scanning electron microscopy, X-ray diffraction, and electron spectroscopy for chemical analysis were used during the investigation.

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.

New influence factor inducing difficulty in selective flotation separation of Cu-Zn mixed sulfide minerals

NASA Astrophysics Data System (ADS)

Deng, Jiu-shuai; Mao, Ying-bo; Wen, Shu-ming; Liu, Jian; Xian, Yong-jun; Feng, Qi-cheng

2015-02-01

Selective flotation separation of Cu-Zn mixed sulfides has been proven to be difficult. Thus far, researchers have found no satisfactory way to separate Cu-Zn mixed sulfides by selective flotation, mainly because of the complex surface and interface interaction mechanisms in the flotation solution. Undesired activation occurs between copper ions and the sphalerite surfaces. In addition to recycled water and mineral dissolution, ancient fluids in the minerals are observed to be a new source of metal ions. In this study, significant amounts of ancient fluids were found to exist in Cu-Zn sulfide and gangue minerals, mostly as gas-liquid fluid inclusions. The concentration of copper ions released from the ancient fluids reached 1.02 × 10-6 mol/L, whereas, in the cases of sphalerite and quartz, this concentration was 0.62 × 10-6 mol/L and 0.44 × 10-6 mol/L, respectively. As a result, the ancient fluid is a significant source of copper ions compared to mineral dissolution under the same experimental conditions, which promotes the unwanted activation of sphalerite. Therefore, the ancient fluid is considered to be a new factor that affects the selective flotation separation of Cu-Zn mixed sulfide ores.

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

Diffusion paths formation for Cu{sup +} ions in superionic Cu{sub 6}PS{sub 5}I single crystals studied in terms of structural phase transition

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

Gagor, A.; Pietraszko, A.; Kaynts, D.

2005-11-15

In order to understand the structural transformations leading to high ionic conductivity of Cu{sup +} ions in Cu{sub 6}PS{sub 5}I argyrodite compound, the detailed structure analysis based on single-crystal X-ray diffraction has been performed. Below the phase transition at T{sub c}=(144-169)K Cu{sub 6}PS{sub 5}I belongs to monoclinic, ferroelastic phase (space group Cc) with ordered copper sublattice. Above T{sub c} delocalization of copper ions begins and crystal changes the symmetry to cubic superstructure with space group F-43c (a{sup '}=19.528A, z=32). Finally, above T{sub 1}=274K increasing disordering of the Cu{sup +} ions heightens the symmetry to F-43m (a=9.794A, z=4). In this work,more » the final structural model of two cubic phases is presented including the detailed temperature evolution of positions and site occupation factors of copper ions (R{sub 1}=0.0397 for F-43c phase, and 0.0245 for F-43m 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.« less

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.

Crumpled graphene nanoreactors

NASA Astrophysics Data System (ADS)

Wang, Zhongying; Lv, Xiaoshu; Chen, Yantao; Liu, Dan; Xu, Xinhua; Palmore, G. Tayhas R.; Hurt, Robert H.

2015-05-01

Nanoreactors are material structures that provide engineered internal cavities that create unique confined nanoscale environments for chemical reactions. Crumpled graphene nanoparticles or ``nanosacks'' may serve as nanoreactors when filled with reactive or catalytic particles and engineered for a specific chemical function. This article explores the behavior of crumpled graphene nanoreactors containing nanoscale ZnO, Ag, Ni, Cu, Fe, or TiO2 particles, either alone or in combination, in a series of case studies designed to reveal their fundamental behaviors. The first case study shows that ZnO nanoparticles undergo rapid dissolution inside the nanoreactor cavity accompanied by diffusive release of soluble products to surrounding aqueous media through the irregular folded shell. This behavior demonstrates the open nature of the sack structure, which facilitates rapid small-molecule exchange between inside and outside that is a requirement for nanoreactor function. In a case study on copper and silver nanoparticles, encapsulation in graphene nanoreactors is shown in some cases to enhance their oxidation rate in aqueous media, which is attributed to electron transfer from the metal core to graphene that bypasses surface oxides and allows reduction of molecular oxygen on the high-area graphene shell. Nanoreactors also allow particle-particle electron transfer interactions that are mediated by the connecting conductive graphene, which give rise to novel behaviors such as galvanic protection of Ag nanoparticles in Ag/Ni-filled nanoreactors, and the photochemical control of Ag-ion release in Ag/TiO2-filled nanoreactors. It is also shown that internal graphene structures within the sacks provide pockets that reduce particle mobility and inhibit particle sintering during thermal treatment. Finally, these novel behaviors are used to suggest and demonstrate several potential applications for graphene nanoreactors in catalysts, controlled release, and environmental remediation.Nanoreactors are material structures that provide engineered internal cavities that create unique confined nanoscale environments for chemical reactions. Crumpled graphene nanoparticles or ``nanosacks'' may serve as nanoreactors when filled with reactive or catalytic particles and engineered for a specific chemical function. This article explores the behavior of crumpled graphene nanoreactors containing nanoscale ZnO, Ag, Ni, Cu, Fe, or TiO2 particles, either alone or in combination, in a series of case studies designed to reveal their fundamental behaviors. The first case study shows that ZnO nanoparticles undergo rapid dissolution inside the nanoreactor cavity accompanied by diffusive release of soluble products to surrounding aqueous media through the irregular folded shell. This behavior demonstrates the open nature of the sack structure, which facilitates rapid small-molecule exchange between inside and outside that is a requirement for nanoreactor function. In a case study on copper and silver nanoparticles, encapsulation in graphene nanoreactors is shown in some cases to enhance their oxidation rate in aqueous media, which is attributed to electron transfer from the metal core to graphene that bypasses surface oxides and allows reduction of molecular oxygen on the high-area graphene shell. Nanoreactors also allow particle-particle electron transfer interactions that are mediated by the connecting conductive graphene, which give rise to novel behaviors such as galvanic protection of Ag nanoparticles in Ag/Ni-filled nanoreactors, and the photochemical control of Ag-ion release in Ag/TiO2-filled nanoreactors. It is also shown that internal graphene structures within the sacks provide pockets that reduce particle mobility and inhibit particle sintering during thermal treatment. Finally, these novel behaviors are used to suggest and demonstrate several potential applications for graphene nanoreactors in catalysts, controlled release, and environmental remediation. Electronic supplementary information (ESI) available: Fig. S1-S5. See DOI: 10.1039/c5nr00963d

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.

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.

Modeling the interaction and toxicity of Cu-Cd mixture to wheat roots affected by humic acids, in terms of cell membrane surface characteristics.

PubMed

Wang, Yi-Min; Zhou, Dong-Mei; Yuan, Xu-Yin; Zhang, Xiao-Hui; Li, Yi

2018-05-01

Responses of wheat (Triticum aestivum L.) seedling roots to the mixtures of copper (Cu), cadmium (Cd) and humic acids (HA) were investigated using the solution culture experiments, focusing on the interaction patterns between multiple metals and their influences on root proton release. A concentration-addition multiplication (CA) model was introduced into the modeling analysis. In comparison with metal ion activities in bulk-phase solutions, the incorporation of ion activities at the root cell membrane surfaces (CMs) (denoted as {Cu 2+ } 0 and {Cd 2+ } 0 ) into the CA model could significantly improve their correlation with RRE (relative root elongation) from 0.819 to 0.927. Modeling analysis indicated that the co-existence of {Cu 2+ } 0 significantly enhanced the rhizotoxicity of {Cd 2+ } 0 , while no significant effect of {Cd 2+ } 0 on the {Cu 2+ } 0 rhizotoxicity. 10 mg/L HA stimulated the root elongation even under metal stress. Although high concentration of metal ions inhibited the root proton release rate (ΔH + ), both the low concentration of metal ions and HA treatments increased the values of ΔH + . In HA-Cu-Cd mixtures, actions of metal ions on ΔH + values were varied intricately among treatments but well modeled by the CA model. We concluded from the CA models that the electrostatic effect is vitally important for explaining the effect of {Cu 2+ } 0 on the rhizotoxicity of {Cd 2+ } 0 , while it plays no unique role in understanding the influence of {Cd 2+ } 0 on the rhizotoxicity of {Cu 2+ } 0. Thus our study provide a novel way for modeling multiple metals behaviors in the environment and understanding the mechanisms of ion interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Temperature preference as an indicator of the chronic toxicity of cupric ions to Mozambique Tilapia

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

Welch, T.J.; Stauffer, J.R. Jr.; Morgan, R.P. II

1989-11-01

Evaluation of the effects of environmental contaminants on aquatic communities has focused primarily on acute bioassays. These bioassays provide rapid and reproducible concentration response curves based on death as an endpoint. In recent years, however, emphasis has shifted towards monitoring sublethal effects of toxicants. Temperature is an easily quantifiable parameter influencing both the behavior and survival of fishes. As poikilotherms, fish use behavioral responses to help regulate body temperature. Fish thermoregulatory behavior may be altered by various toxic substances. Some researchers found that a 24 hr exposure of sublethal concentrations of copper caused a significant decrease in preferred temperature ofmore » fathead minnows (Pimephales promelas), although the results were confounded due to variations in copper concentrations. In this study, the authors examined the feasibility of using acute temperature preference tests to assess the chronic toxicity of low concentrations of free cupric ions to Mozambique tilapia, Oreochromis mossambicus (Peters).« less

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

Dissolution and aggregation of Cu nanoparticles in culture media: effects of incubation temperature and particles size

NASA Astrophysics Data System (ADS)

Li, Lingxiangyu; Fernández-Cruz, María Luisa; Connolly, Mona; Schuster, Michael; Navas, José María

2015-01-01

Here, the effects of incubation temperature and particle size on the dissolution and aggregation behavior of copper nanoparticles (CuNPs) in culture media were investigated over 96 h, equivalent to the time period for acute cell toxicity tests. Three CuNPs with the nominal sizes of 25, 50, and 100 nm and one type of micro-sized particles (MPs, 500 nm) were examined in culture media used for human and fish hepatoma cell lines acute tests. A large decrease in sizes of CuNPs in the culture media was observed in the first 24 h incubation, and subsequently the sizes of CuNPs changed slightly over the following 72 h. Moreover, the decreasing rate in size was significantly dependent on the incubation temperature; the higher the incubation temperature, the larger the decreasing rate in size. In addition to that, we also found that the release of copper ions depended on the incubation temperature. Moreover, the dissolution rate of Cu particles increased very fast in the first 24 h, with a slight increase over the following 72 h.

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.

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.

Adsorption kinetic and desorption studies of Cu2+ on Multi-Carboxylic-Functionalized Silica Gel

NASA Astrophysics Data System (ADS)

Li, Min; Meng, Xiaojing; Liu, Yushuang; Hu, Xinju; Liang, Xiuke

2018-01-01

In the present study, the adsorption behavior of copper (II) ion from aqueous solution onto multi-carboxylic-functionalized silica gel (SG-MCF) has been investigated in detail by means of batch and column experiments. Batch experiments were performed to evaluate the effects of contact time on adsorption capacity of copper (II) ion. The kinetic data were analyzed on the basis of the pseudo-first-order kinetic and the pseudo-second-order kinetic models and consequently, the pseudo-second-order kinetic can better describe the adsorption process than the pseudo-first-order kinetic model. And the adsorption mechanism of the process was studied by intra-particle and film diffusion, it was found out that the adsorption rate was governed primarily by film diffusion to the adsorption onto the SG-MCF. In addition, column experiments were conducted to assess the effects initial inlet concentration and the flow rate on breakthrough time and adsorption capacity ascertaining the practical applicability of the adsorbent. The results suggest that the total amount of adsorbed copper (II) ion increased with declined flow rate and increased the inlet concentration. The adsorption-desorption experiment confirmed that adsorption capacity of copper (II) ion didn’t present an obvious decrease after five cycles.

Biological Impact of Bioactive Glasses and Their Dissolution Products.

PubMed

Hoppe, Alexander; Boccaccini, Aldo R

2015-01-01

For many years, bioactive glasses (BGs) have been widely considered for bone tissue engineering applications due to their ability to bond to hard as well as soft tissue (a property termed bioactivity) and for their stimulating effects on bone formation. Ionic dissolution products released during the degradation of the BG matrix induce osteogenic gene expression leading to enhanced bone regeneration. Recently, adding bioactive metallic ions (e.g. boron, copper, cobalt, silver, zinc and strontium) to silicate (or phosphate and borate) glasses has emerged as a promising route for developing novel BG formulations with specific therapeutic functionalities, including antibacterial, angiogenic and osteogenic properties. The degradation behaviour of BGs can be tailored by adjusting the glass chemistry making these glass matrices potential carrier systems for controlled therapeutic ion release. This book chapter summarises the fundamental aspects of the effect of ionic dissolution products from BGs on osteogenesis and angiogenesis, whilst discussing novel BG compositions with controlled therapeutic ion release. © 2015 S. Karger AG, Basel.

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.

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.

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.

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.

In vitro chemical and biological effects of Ag, Cu and Cu + Zn adjunction in 46S6 bioactive glasses

NASA Astrophysics Data System (ADS)

Bunetel, L.; Wers, E.; Novella, A.; Bodin, A.; Pellen-Mussi, P.; Oudadesse, H.

2015-09-01

Three bioactive glasses belonging to the system SiO2-CaO- Na2O-P2O5 elaborated by conventional melt-quenching techniques were doped with silver, copper and copper + zinc. They were characterized using the usual physical methods. Human osteoblast cells Saos-2 and human endothelial cells EAhy926 were used for viability assays and to assess the metallic ions, self toxicity. Human monocyte cells THP-1 were used to measure interleukins IL1β and IL6 release. Glass chemical structures did not vary much on introduction of metal ions. A layer of hydroxyapatite was observed on every glass after 30 days of SBF immersion. A proliferative action was seen on Saos-2 after 24 h of incubation, EAhy926 growth was not affected. For both cell lines, a moderate cytotoxicity was found after 72 h. Dose-dependent toxic effects of Ag, Cu and Zn ions were observed on Saos-2 and EAhy926 cells. Measured CD50 of silver against these two cell lines were 8 to 20 fold lower than copper and zinc’s. Except undoped control glass, all doped glasses tested showed anti-inflammatory properties by preventing IL1β and IL6 excretion by differentiated THP-1. In conclusion, strictly monitored adjunction of metal ions to bioglasses ensures good anti-inflammatory properties without altering their biocompatibility.

Divalent cation interactions with oligogalacturonides.

PubMed

Cescutti, P; Rizzo, R

2001-07-01

The conformational properties of high and low molecular weight galacturonides were investigated in relation to the ability of oligomers with degree of polymerization >10 to act as elicitors of plant defense mechanisms. Oligomers from polygalacturonate were obtained by means of enzymatic hydrolysis. Two fractions exhibiting high and low average degrees of polymerization were isolated by solvent fractionation and characterized by means of electrospray mass spectrometry. The conformational behaviors of the two fractions were investigated in the presence of different divalent cations using circular dichroism. Calcium, copper, and zinc ions were able to induce a conformational transition in both fractions. When in the presence of the high molecular weight fraction, copper and zinc ions were much more effective than calcium ions, whereas the efficiency was much reduced with low molecular weight oligomers.

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.

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.

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.

Structure, corrosion behavior and mechanical property of a novel poly(vinyl alcohol) composite in simulated body fluid.

PubMed

Li, Juan; Suo, Jinping; Zou, Peng; Jia, Lintao; Wang, Shifang

2010-01-01

The data for long-term drug-delivery systems are scarce compared to the short-term systems because the required research efforts are more time-consuming. In this study, we report a novel cross-linked composite based on poly(vinyl alcohol) (PVA) containing cupric ions for long-term delivery, which is helpful for contraception and trace element balance in the human body. The composition, corrosion products, crystal structure, chemical structure and mechanical stability of the composite, after being immersed in simulated body fluid (SBF) for one year, were studied by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and mechanical testing. The results show that no other new elements, such as P, Cl and Ca, appear on the surface of the composite and no Cu(2)O was formed after immersion in SBF for one year. The effectiveness of copper can be greatly improved and the side-effects caused by these compounds might also be eliminated. Furthermore, this novel composite exhibits long-term mechanical stability in SBF. The present in vitro long-term data suggest that this novel copper-containing composite may serve as a substitute for conventional materials of copper-containing intrauterine devices (Cu-IUDs) and as a carrier for controlled-release material in a variety of other applications.

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 be included in such calculations. Copyright © 2011 Elsevier B.V. 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.

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.

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.

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

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.

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.

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.

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.

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.

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.

A dual pH/thermal responsive nanocarrier for combined chemo-thermotherapy based on a copper-doxorubicin complex and gold nanorods

NASA Astrophysics Data System (ADS)

Lei, Mingzhu; Ma, Man; Pang, Xiaojuan; Tan, Fengping; Li, Nan

2015-09-01

The development of treatment protocols that results in a complete response to chemotherapy has been hampered by low efficacy and systemic toxicity. Here, we created a pH sensitive copper-doxorubicin complex within the core of temperature-sensitive liposomes to maintain the stability during blood circulation and trigger Dox release in the tumor site. Synergistically, we also rationally applied gold nanorods (AuNRs) coupled with near-infrared (NIR) field strength to produce a precise and localized temperature, which not only remotely controlled the drug release but also directly destroyed the tumor, to enhance the therapeutic efficacy. As expected, the in vitro release studies showed that the drug release from CuDox-TSLs (Copper ion mediated Doxorubicin loading-Temperature Sensitive Liposomes) was both pH-dependent and temperature-dependent. Furthermore, MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assays showed that CuDox-TSLs combined with AuNRs exhibited a closer antiproliferative activity to free Dox in MCF-7 cells. The efficient intracellular Dox release from CuDox-TSLs toward the tumor cells further confirmed the anti-tumor effect. Moreover, the in vivo imaging and biodistribution studies revealed that CuDox-TSLs combined with AuNRs could actively target the tumor site. In addition, the therapeutic studies in MCF-7 nude mice exhibited CuDox-TSLs plus AuNRs in combination with NIR irradiation inhibited tumor growth to a great extent and possessed much lower side effects, which were further confirmed by systemic histological analyses. All detailed evidence suggested a considerable potential of CuDox-TSLs combined with AuNRs for treatment of metastatic cancer.The development of treatment protocols that results in a complete response to chemotherapy has been hampered by low efficacy and systemic toxicity. Here, we created a pH sensitive copper-doxorubicin complex within the core of temperature-sensitive liposomes to maintain the stability during blood circulation and trigger Dox release in the tumor site. Synergistically, we also rationally applied gold nanorods (AuNRs) coupled with near-infrared (NIR) field strength to produce a precise and localized temperature, which not only remotely controlled the drug release but also directly destroyed the tumor, to enhance the therapeutic efficacy. As expected, the in vitro release studies showed that the drug release from CuDox-TSLs (Copper ion mediated Doxorubicin loading-Temperature Sensitive Liposomes) was both pH-dependent and temperature-dependent. Furthermore, MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assays showed that CuDox-TSLs combined with AuNRs exhibited a closer antiproliferative activity to free Dox in MCF-7 cells. The efficient intracellular Dox release from CuDox-TSLs toward the tumor cells further confirmed the anti-tumor effect. Moreover, the in vivo imaging and biodistribution studies revealed that CuDox-TSLs combined with AuNRs could actively target the tumor site. In addition, the therapeutic studies in MCF-7 nude mice exhibited CuDox-TSLs plus AuNRs in combination with NIR irradiation inhibited tumor growth to a great extent and possessed much lower side effects, which were further confirmed by systemic histological analyses. All detailed evidence suggested a considerable potential of CuDox-TSLs combined with AuNRs for treatment of metastatic cancer. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04353k

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

Hydrogen transport behavior of metal coatings for plasma-facing components

NASA Astrophysics Data System (ADS)

Anderl, R. A.; Holland, D. F.; Longhurst, G. R.

1990-12-01

Plasma-facing components for experimental and commercial fusion reactor studies may include cladding or coatings of refractory metals like tungsten on metallic structural substrates such as copper, vanadium alloys and austenitic stainless steel. Issues of safety and fuel economy include the potential for inventory buildup and permeation of tritium implanted into the plasma-facing surface. This paper reports on laboratory-scale studies with 3 keV D +3 ion beams to investigate the hydrogen transport behavior in tungsten coatings on substrates of copper. These experiments entailed measurements of the deuterium re-emission and permeation rates for tungsten, copper, and tungsten-coated copper specimens at temperatures ranging from 638 to 825 K and implanting particle fluxes of approximately 5 × 10 19 D/m 2 s. Diffusion constants and surface recombination coefficients with enhancement factors due to sputtering were obtained from these measurements. These data may be used in calculations to estimate permeation rates and inventory buildups for proposed diverter designs.

Geochemical speciation and dynamic of copper in tropical semi-arid soils exposed to metal-bearing mine wastes.

PubMed

Perlatti, Fabio; Otero, Xosé Luis; Macias, Felipe; Ferreira, Tiago Osório

2014-12-01

The potentially hazardous effects of rock wastes disposed at open pit in three different areas (Pr: Ore processing; Wr: Waste rock and Bd: Border) of an abandoned copper mine were evaluated in this study, with emphasis on acid drainage generation, metal contamination and copper geochemical dynamics in soils. Samples of waste rock were analyzed by Energy dispersive X-ray fluorescence (XRF), scanning electron microscopy with microanalysis (SEM-EDS) and X-ray diffraction (XRD). Soil samples were analyzed to determine the total metal contents (XRF), mineralogy (XRD), pH (H2O and H2O2), organic and inorganic carbon, % of total N, S and P, particle size, and a sequential extraction procedure was used to identify the different copper fractions. As a result of the prevalence of carbonates over sulphides in the wastes, the soil pH remained close to neutral, with absence of acid mine drainage. The geochemical interaction between these mineral phases seems to be the main mechanism to release Cu(2)(+) ions. Total Cu in soils from the Pr area reached 11,180mg.kg(-1), while in Wr and Bd areas the values reached, on average, 4683 and 1086mg.kg(-1), respectively, indicating a very high level of soil contamination. In the Pr and Wr, the Cu was mainly associated with carbonates and amorphous iron oxides. In the Bd areas, the presence of vegetation has influenced the geochemical behavior of copper by increasing the dissolution of carbonates, affecting the buffer capacity of soils against sulphide oxidation, reducing the pH levels and enhancing the proportion of exchangeable and organic bound Cu. The present findings show that the use of plants or organic amendments in mine sites with high concentration of Cu carbonate-containing wastes should be viewed with caution, as the practice may enhance the mobilization of copper to the environment due to an increase in the rate of carbonates dissolution. Copyright © 2014 Elsevier B.V. All rights reserved.

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

Copper transport mediated by nanocarrier systems in a blood-brain barrier in vitro model.

PubMed

Fehse, Susanne; Nowag, Sabrina; Quadir, Mohiuddin; Kim, Kwang Sik; Haag, Rainer; Multhaup, Gerd

2014-05-12

Copper (Cu) is a cofactor of various metalloenzymes and has a role in neurodegenerative diseases with disturbed Cu homeostasis, for example, in Alzheimer's disease (AD) and Menkes disease. To address Cu imbalances, we synthesized two different dendritic nanoparticles (NP) for the transport of Cu(II) ions across the blood-brain barrier (BBB). The synthesized NPs show low toxicity and high water solubility and can stabilize high amounts of Cu(II). The Cu(II)-laden NPs crossed cellular membranes and increased the cellular Cu level. A human brain microvascular endothelial cell (HBMEC) model was established to investigate the permeability of the NPs through the BBB. By comparing the permeability × surface area product (PSe) of reference substances with those of NPs, we observed that NPs crossed the BBB model two times more effectively than (14)C-sucrose and sodium fluorescein (NaFl) and up to 60× better than Evans Blue labeled albumin (EBA). Our results clearly indicate that NPs cross the BBB model effectively. Furthermore, Cu was shielded by the NPs, which decreased the Cu toxicity. The novel design of the core-shell NP enabled the complexation of Cu(II) in the outer shell and therefore facilitated the pH-dependent release of Cu in contrast to core-multishell NPs, where the Cu(II) ions are encapsulated in the core. This allows a release of Cu into the cytoplasm. In addition, by using a cellular detection system based on a metal response element with green fluorescent protein (MRE-GFP), we demonstrated that Cu could also be released intracellularly from NPs and is accessible for biological processes. Our results indicate that NPs are potential candidates to rebalance metal-ion homeostasis in disease conditions affecting brain and neuronal systems.

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…

Exothermic low temperature sintering of Cu nanoparticles

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

Mittal, Jagjiwan; Lin, Kwang-Lung, E-mail: matkllin@mail.ncku.edu.tw

2015-11-15

Sintering of the Cu nanoparticle at low temperatures resulted in exothermic behavior after its initiation. The calorimetry study of the heating of a 20 nm copper nanoparticles agglomerate revealed the evolution of 41.17 J/g of heat between 170 °C and 270 °C. High resolution transmission electron microscopy (HRTEM) images indicated that the heat generation was accompanied by sintering. The surface energy of the 20 nm copper nanoparticles was estimated to be 1.23 × 10{sup 3} erg/cm{sup 2} based on the heat released during sintering. The in situ high resolution transmission electron microscope (HRTEM) investigation showed that vigorous sintering occurred betweenmore » 217 and 234 °C, which took place through the dislocation sintering mechanism. - Highlights: • Calorimetry showed exothermic behavior during heating of Cu nanoparticles between 170 and 270 °C. • Heat released due to the sintering of Cu nanoparticles was demonstrated by HRTEM. • Surface energy of 20 nm copper nanoparticles was estimated to be 1.23 × 10{sup 3} erg/cm{sup 2} during sintering. • Growth in crystallite sizes during sintering is disclosed by X-ray diffraction. • In situ HRTEM heating study showed occurrence of sintering through dislocation mechanism.« less

Effect of aluminum, zinc, copper, and lead on the acid-base properties of water extracts from soils

NASA Astrophysics Data System (ADS)

Motuzova, G. V.; Makarychev, I. P.; Petrov, M. I.

2013-01-01

The potentiometric titration of water extracts from the upper horizons of taiga-zone soils by salt solutions of heavy metals (Pb, Cu, and Zn) showed that their addition is an additional source of the extract acidity because of the involvement of the metal ions in complexation with water-soluble organic substances (WSOSs). At the addition of 0.01 M water solutions of Al(NO3)3 to water extracts from soils, Al3+ ions are also involved in complexes with WSOSs, which is accompanied by stronger acidification of the extracts from the upper horizon of soddy soils (with a near-neutral reaction) than from the litter of bog-podzolic soil (with a strongly acid reaction). The effect of the Al3+ hydrolysis on the acidity of the extracts is insignificantly low in both cases. A quantitative relationship was revealed between the release of protons and the ratio of free Cu2+ ions to those complexed with WSOSs at the titration of water extracts from soils by a solution of copper salt.

Radiation induced deposition of copper nanoparticles inside the nanochannels of poly(acrylic acid)-grafted poly(ethylene terephthalate) track-etched membranes

NASA Astrophysics Data System (ADS)

Korolkov, Ilya V.; Güven, Olgun; Mashentseva, Anastassiya A.; Atıcı, Ayse Bakar; Gorin, Yevgeniy G.; Zdorovets, Maxim V.; Taltenov, Abzal A.

2017-01-01

Poly(ethylene terephthalate) PET, track-etched membranes (TeMs) with 400 nm average pore size were UV-grafted with poly(acrylic acid) (PAA) after oxidation of inner surfaces by H2O2/UV system. Carboxylate groups of grafted PAA chains were easily complexed with Cu2+ ions in aqueous solutions. These ions were converted into metallic copper nanoparticles (NPs) by radiation-induced reduction of copper ions in aqueous-alcohol solution by gamma rays in the dose range of 46-250 kGy. Copper ions chelating with -COOH groups of PAA chains grafted on PET TeMs form polymer-metal ion complex that prevent the formation of agglomerates during reduction of copper ions to metallic nanoparticles. The detailed analysis by X-Ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the deposition of copper nanoparticles with the average size of 70 nm on the inner surface of nanochannels of PET TeMs. Samples were also investigated by FTIR, ESR spectroscopies to follow copper ion reduction.

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.

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

Metallurgical characterization, galvanic corrosion, and ionic release of orthodontic brackets coupled with Ni-Ti archwires.

PubMed

Darabara, Myrsini S; Bourithis, Lefteris I; Zinelis, Spiros; Papadimitriou, George D

2007-04-01

In orthodontics, a combination of metallic alloys is placed into the oral cavity during medical treatment and thus the corrosion resistance and ionic release of these appliances is of vital importance. The aim of this study is to investigate the elemental composition, microstructure, hardness, corrosion properties, and ionic release of commercially available orthodontic brackets and Copper Ni-Ti archwires. Following the assessment of the elemental composition of the orthodontic wire (Copper Ni-Ti) and the six different brackets (Micro Loc, Equilibrium, OptiMESH(XRT), Gemini, Orthos2, and Rematitan), cyclic polarization curves were obtained for each material to estimate the susceptibility of each alloy to pitting corrosion in 1M lactic acid. Galvanic corrosion between the orthodontic wire and each bracket took place in 1M lactic acid for 28 days at 37 degrees C and then the ionic concentration of Nickel and Chromium was studied. The orthodontic wire is made up from a Ni-Ti alloy with copper additions, while the orthodontic brackets are manufactured by different stainless steel grades or titanium alloys. All tested wires and brackets with the exception of Gemini are not susceptible to pitting corrosion. In galvanic corrosion, following exposure for 28 days, the lowest potential difference (approximately 250 mV) appears for the orthodontic wire Copper Ni-Ti and the bracket made up from pure titanium (Rematitan) or from the stainless steel AISI 316 grade (Micro Loc). Following completion of the galvanic corrosion experiments, measurable quantities of chromium and nickel ions were found in the residual lactic acid solution. (c) 2006 Wiley Periodicals, Inc.

Cu(II) potentiation of Alzheimer Abeta1-40 cytotoxicity and transition on its secondary structure.

PubMed

Dai, Xue-Ling; Sun, Ya-Xuan; Jiang, Zhao-Feng

2006-11-01

Mounting evidence has shown that dyshomeostasis of the redox-active biometals such as Cu and Fe can lead to oxidative stress, which plays a key role in the neuropathology of Alzheimer' disease (AD). Here we demonstrate that with the formation of Cu(II).beta1-40 complexes, copper markedly potentiates the neurotoxicity exhibited by beta-amyloid peptide (Ab). A greater amount of hydrogen peroxide was released when Cu(II).beta1-40 complexes was added to the xanthine oxidase/xanthine system detected by potassium iodide spectrophotometry. Copper bound to Abeta1-40 was observed by electron paramagnetic resonance (EPR) spectroscopy. Circular dichroism (CD) studies indicated that copper chelation could cause a structural transition of Abeta. The addition of copper to Ab introduced an increase on beta-sheet as well as alpha-helix, which may be responsible for the aggregation of Abeta. We hypothesized that Abeta aggregation induced by copper may be responsible for local injury in AD. The interaction between Cu(2+) and Ab also provides a possible mechanism for the enrichment of metal ions in amyloid plaques in the AD brain.

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.

Dynamics of the sorption of copper(II) and silver(I) by materials based on sulfoethylchitosan with various degrees of crosslinking

NASA Astrophysics Data System (ADS)

Petrova, Yu. S.; Pestov, A. V.; Alifkhanova, L. M. k.; Neudachina, L. K.

2017-04-01

Optimum conditions of the dynamic concentration of copper(II) and silver(I) ions simultaneously present in a solution with N-(2-sulfoethyl)chitosan with a degree of modification equal to 0.5 and different degrees of crosslinking by glutaraldehyde are determined. The values of coefficients of selectivity K Ag/Cu are determined under dynamic conditions. It is shown that the selectivity of the sorption of silver(I) increases (compared to copper(II)) as the degree of crosslinking of sorbents based on N-(2-sulfoethyl)chitosan is raised. Mathematical treatment of the obtained dynamic curves is performed according to the Thomas, Adams-Bohart, and Yoon and Nelson models. As a result, the values of dynamic capacity of sorbents, the rate constant of the reaction, and the release time of 50% of the sorbate are determined. The quantitative desorption of copper and silver from the surface of sorbents is achieved by using 1 mol/dm3 solution of nitric acid.

A New Modality for Cancer Treatment--Nanoparticle Mediated Microwave Induced Photodynamic Therapy.

PubMed

Yao, Mengyu; Ma, Lun; Li, Lihua; Zhang, Junying; Lim, Rebecca; Chen, Wei; Zhang, Yu

2016-10-01

Photodynamic therapy (PDT) has attracted ever-growing attention as a promising modality for cancer treatment. However, due to poor tissue penetration by light, photodynamic therapy has rarely been used for deeply situated tumors. This problem can be solved if photosensitizers are activated by microwaves (MW) that are able to penetrate deeply into tissues. Here, for the first time, we report microwave-induced photodynamic therapy and exploit copper cysteamine nanoparticles as a new type of photosensitizer that can be activated by microwaves to produce singlet oxygen for cancer treatment. Both in vitro and in vivo studies on a rat osteosarcoma cell line (UMR 106-01) have shown significant cell destruction using copper cysteamine (Cu-Cy) under microwave activation. The heating effects and the release of copper ions from Cu-Cy upon MW stimulation are the main mechanisms for the generation of reactive oxygen species that are lethal bullets for cancer destruction. The copper cysteamine nanoparticle-based microwave-induced photodynamic therapy opens a new door for treating cancer and other diseases.

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.

[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 level, using stepwise multiple linear regression and cross validation on the dataset which is consisting of 44 groups of copper ion content information in the polluted vegetation leaves from Dexing Copper Mine in Jiangxi Province to build up a statistical model by also incorporating the HJ-1 satellite images. This model was then used to estimate the copper content distribution over the whole research area at Dexing Copper Mine. The result has shown that there is strong statistical significance of the model which revealed the most sensitive waveband to copper ion is located at 516 nm. The distribution map illustrated that the copper ion content is generally in the range of 0-130 mg · kg⁻¹ in the vegetation covering area at Dexing Copper Mine and the most seriously polluted area is located at the South-east corner of Dexing City as well as the mining spots with a higher value between 80 and 100 mg · kg⁻¹. This result is consistent with the ground observation experiment data. The distribution map can certainly provide some important basic data on the copper pollution monitoring and treatment.

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.

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.

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.

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.

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...

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.

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.

Aluminum surface corrosion and the mechanism of inhibitors using pH and metal ion selective imaging fiber bundles.

PubMed

Szunerits, Sabine; Walt, David R

2002-02-15

The localized corrosion behavior of a galvanic aluminum copper couple was investigated by in situ fluorescence imaging with a fiber-optic imaging sensor. Three different, but complementary methods were used for visualizing remote corrosion sites, mapping the topography of the metal surface, and measuring local chemical concentrations of H+, OH-, and Al3+. The first method is based on a pH-sensitive imaging fiber, where the fluorescent dye SNAFL was covalently attached to the fiber's distal end. Fluorescence images were acquired as a function of time at different areas of the galvanic couple. In a second method, the fluorescent dye morin was immobilized on the fiber-optic imaging sensor, which allowed the in situ localization of corrosion processes on pure aluminum to be visualized over time by monitoring the release of Al3+. The development of fluorescence on the aluminum surface defined the areas associated with the anodic dissolution of aluminum. We also investigated the inhibition of corrosion of pure aluminum by CeCl3 and 8-hydroxyquinoline. The decrease in current, the decrease in the number of active sites on the aluminum surface, and the faster surface passivation are all consistent indications that cerium chloride and 8-hydroxyquinoline inhibit corrosion effectively. From the number and extent of corrosion sites and the release of aluminum ions monitored with the fiber, it was shown that 8-hydroxyquinoline is a more effective inhibitor than cerium chloride.

Multifunctional mesoporous bioactive glasses for effective delivery of therapeutic ions and drug/growth factors.

PubMed

Wu, Chengtie; Chang, Jiang

2014-11-10

Regeneration of large-size bone defects represents a significant challenge clinically, which requires the use of scaffolds with multifunction, such as anti-bacterial activity, and stimulation of osteogenesis and angiogenesis. It is known that functional ions or drug/growth factors play an important role to stimulate tissue regeneration. Mesoporous bioactive glasses (MBG) possess excellent bioactivity and drug-delivery ability as well as effective ionic release in the body fluids microenvironment due to its specific mesoporous structure and large surface area. For these reasons, functional ions (e.g. lithium (Li), strontium (Sr), Copper (Cu) and Boron (B)) and drug/growth factors (e.g. dexamethasone, vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP)) have been incorporated into MBG, which shows high loading efficiency and effective release. The release of therapeutic ions and drug/growth factors from MBG offers it multifunctional properties, such as improved osteogenesis, angiogenesis, anti-bacterial/cancer activity. However, there is no a systematic review about delivery of therapeutic ions and drugs/growth factors from MBG for the functional effect on the tissue regeneration despite that significant progress has been achieved in the past five years. Therefore, in this review, we mainly focused on the new advances for the functional effect of delivering therapeutic ions and drugs/growth factors on the ostegeogenesis, angiogenesis and antibacterial activity. It is expected that the review will offer new concept to develop multifunctional biomaterials for bone regeneration by the synergistic effect of therapeutic ions and drug/growth factors. Copyright © 2014 Elsevier B.V. All rights reserved.

Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

NASA Technical Reports Server (NTRS)

Kleinsasser, A. W.; Barner, J. B.

1997-01-01

The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

Adsorption of Cu(II) from aqueous solution on sulfuric acid treated palygorskite

NASA Astrophysics Data System (ADS)

Niu, Yan-Ning; Yuan, Yuan; Gao, Wei-Xin; Qian, Sheng; Sun, Wen

2018-03-01

The absorption behavior of Cu2+ from aqueous solution on sulfuric acid treated palygorskite were investigated, the results showed that palygorskite had high absorption ability for Cu2+ from aqueous solution. Effects of the shaking time, pH and the copper ion concentration on the removal rate were discussed. The absorption behavior of Cu2+ could be well imitated by the Langmuir isothermal equation.

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.

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.

Detection of Cu2+ in Water Based on Histidine-Gold Labeled Multiwalled Carbon Nanotube Electrochemical Sensor

PubMed Central

Zhu, Rilong; Zhou, Gangqiang; Tang, Fengxia; Wang, Yeyao

2017-01-01

Based on the strong interaction between histidine and copper ions and the signal enhancement effect of gold-labeling carbon nanotubes, an electrochemical sensor is established and used to measure copper ions in river water. In this study the results show that the concentrations of copper ion have well linear relationship with the peak current in the range of 10−11–10−7 mol/L, and the limit of detection is 10−12 mol/L. When using this method to detect copper ions in the Xiangjiang River, the test results are consistent with the atomic absorption method. This study shows that the sensor is convenient to be used in daily monitoring of copper ions in river water. PMID:28408929

Potential immobilized Saccharomyces cerevisiae as heavy metal removal

NASA Astrophysics Data System (ADS)

Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

2015-05-01

Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

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 by ToF-SIMS. Dynamic SIMS provided shallow depth profile of corroded copper sample. The third set of the experiments was related to electrochemical noise (EN) measurement through copper coupons to pipes. Calculating corrosion rate of a metal and predicting exactly how long it lasts are problematic since the metal corrosion may be caused by combined corrosion types. Many other metals undergo not only uniform corrosion, but localized corrosion. Uniform corrosion may be conducive for copper pipe to prevent it from further severe corrosion and form passivated film, but localized corrosion causes pinhole leaks and limits the copper pipe applications. The objective of this set of experiment is to discuss the application of electrochemical noise approaches to drinking water copper corrosion problems. Specially, a fundamental description of EN is presented including a discussion of how to interpret the results and technique limitations. Although it was indicated with electrochemical analysis that the corrosion activity was affected by orthophosphate addition in the short-term test, no copper-phosphate complex or compound was found by copper surface characterization. Apparently, orthophosphate can inhibit corrosion by adsorption on the copper surface, but cannot form solid complexes with copper in such a short time, 2 days. When polyphosphate was added into recirculating copper pipe system, copper level increased and polarization resistance decreased. Greenish blue residue on the copper pipe was suspected as copper phosphate complex and corrosion inhibition mechanism was proposed.

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.

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

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.

Effects of Fixed Orthodontic Treatment Using Conventional, Copper-Included, and Epoxy-Coated Nickel-Titanium Archwires on Salivary Nickel Levels: A Double-Blind Randomized Clinical Trial.

PubMed

Khaneh Masjedi, Mashallah; Niknam, Ozra; Haghighat Jahromi, Nima; Javidi, Pedram; Rakhshan, Vahid

2016-11-01

Orthodontic archwires, especially nickel-titanium (NiTi) ones, are a major source of nickel release. Despite their importance, no in vivo studies have assessed the ion release from conventional or new generations of NiTi archwires (copper-included and epoxy-coated). This double-blind parallel randomized clinical trial was done on 84 saliva specimens sampled at two time points from 42 orthodontic patients. The patients were randomly divided into three groups of NiTi, copper NiTi (NiTiCu), and epoxy NiTi archwires (n = 14 each). The effects of 2-month treatment, wire types, gender, and age on pretreatment, posttreatment, and time-dependent differences were analyzed statistically (α = 0.05). Salivary nickel concentrations were 10.4571 ± 0.77168 and 11.0779 ± 0.81232 μg/L, respectively, in the baseline and second month. This increase was significant (P = 0.0000, paired t test). The extents of nickel increase in different groups were 0.8279 ± 0.14 (NiTi), 0.6493 ± 0.10 (NiTiCu), and 0.385 ± 0.11 (epoxy-coated NiTi) μg/L (P = 0.0000, one-way analyses of variance (ANOVA)). Differences between each two archwire types were significant (P = 0.000, Tukey). Age and gender did not play a role. It can be concluded that NiTi archwires might increase nickel salivary levels. Epoxy-coated NiTi followed by copper NiTi archwires might release less nickel compared to conventional NiTi ones.

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...

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...

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.

Proton and metal ion binding to natural organic polyelectrolytes-II. Preliminary investigation with a peat and a humic acid

USGS Publications Warehouse

Marinsky, J.A.; Reddy, M.M.

1984-01-01

We summarize here experimental studies of proton and metal ion binding to a peat and a humic acid. Data analysis is based on a unified physico-chemical model for reaction of simple ions with polyelectrolytes employing a modified Henderson-Hasselbalch equation. Peat exhibited an apparent intrinsic acid dissociation constant of 10-4.05, and an apparent intrinsic metal ion binding constant of: 400 for cadmium ion; 600 for zinc ion; 4000 for copper ion; 20000 for lead ion. A humic acid was found to have an apparent intrinsic proton binding constant of 10-2.6. Copper ion binding to this humic acid sample occurred at two types of sites. The first site exhibited reaction characteristics which were independent of solution pH and required the interaction of two ligands on the humic acid matrix to simultaneously complex with each copper ion. The second complex species is assumed to be a simple monodentate copper ion-carboxylate species with a stability constant of 18. ?? 1984.

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.

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.

A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

NASA Astrophysics Data System (ADS)

Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

2015-02-01

Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully.

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.

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...

Selective ion exchange governed by the Irving-Williams series in K2Zn3[Fe(CN)6]2 nanoparticles: toward a designer prodrug for Wilson's disease.

PubMed

Kandanapitiye, Murthi S; Wang, Fan Jennifer; Valley, Benjamin; Gunathilake, Chamila; Jaroniec, Mietek; Huang, Songping D

2015-02-16

The principle of the Irving-Williams series is applied to the design of a novel prodrug based on K2Zn3[Fe(CN)6]2 nanoparticles (ZnPB NPs) for Wilson's disease (WD), a rare but fatal genetic disorder characterized by the accumulation of excess copper in the liver and other vital organs. The predetermined ion-exchange reaction rather than chelation between ZnPB NPs and copper ions leads to high selectivity of such NPs for copper in the presence of the other endogenous metal ions. Furthermore, ZnPB NPs are highly water-dispersible and noncytotoxic and can be readily internalized by cells to target intracellular copper ions for selective copper detoxification, suggesting their potential application as a new-generation treatment for WD.

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.

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.

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

Corrosion of dental aluminium bronze in neutral saline and saline lactic acid.

PubMed

Tibballs, J E; Erimescu, Raluca

2006-09-01

To compare the corrosion behaviours of two aluminium bronze, dental casting alloys during a standard immersion test and for immersion in neutral saline. Cast specimens of aluminium bronzes with 1.4 wt% Fe (G) and 4 wt% Fe (N) were subject to progressively longer periods (up to in total 7 days) immersed in 0.1 M saline, 0.1 M lactic acid solutions and examined by scanning electron microscopy with EDX analysis. Immersion in 0.1M neutral saline was for 7 days. In the acidic solution, exposed interdendritic volumes in alloy N corroded completely away in 7 days with dissolution of Ni-enriched precipitate species as well as the copper-rich matrix. Alloy G begins to corrode more slowly but by a similar mechanism. The number density of an Fe-enriched species is insufficient to maintain a continuous galvanic potential to the copper matrix, and dissolution becomes imperceptible. In neutral saline solution, galvanic action alone caused pit-etching, without the dissolution of either precipitate species. The upper limit for the total dissolution of metallic ions in the standard immersion test can be set at 200 microg cm(-2). Aluminium bronze dental alloys can be expected to release both copper and nickel ions into an acidic oral environment.

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species

PubMed Central

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N.; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W. M. R.

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect. PMID:27649315

Penetration and Effectiveness of Micronized Copper in Refractory Wood Species.

PubMed

Civardi, Chiara; Van den Bulcke, Jan; Schubert, Mark; Michel, Elisabeth; Butron, Maria Isabel; Boone, Matthieu N; Dierick, Manuel; Van Acker, Joris; Wick, Peter; Schwarze, Francis W M R

2016-01-01

The North American wood decking market mostly relies on easily treatable Southern yellow pine (SYP), which is being impregnated with micronized copper (MC) wood preservatives since 2006. These formulations are composed of copper (Cu) carbonate particles (CuCO3·Cu(OH)2), with sizes ranging from 1 nm to 250 μm, according to manufacturers. MC-treated SYP wood is protected against decay by solubilized Cu2+ ions and unreacted CuCO3·Cu(OH)2 particles that successively release Cu2+ ions (reservoir effect). The wood species used for the European wood decking market differ from the North American SYP. One of the most common species is Norway spruce wood, which is poorly treatable i.e. refractory due to the anatomical properties, like pore size and structure, and chemical composition, like pit membrane components or presence of wood extractives. Therefore, MC formulations may not suitable for refractory wood species common in the European market, despite their good performance in SYP. We evaluated the penetration effectiveness of MC azole (MCA) in easily treatable Scots pine and in refractory Norway spruce wood. We assessed the effectiveness against the Cu-tolerant wood-destroying fungus Rhodonia placenta. Our findings show that MCA cannot easily penetrate refractory wood species and could not confirm the presence of a reservoir effect.

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

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

Insoluble zinc, cupric and tin pyrophosphates inhibit the formation of volatile sulphur compounds.

PubMed

Jonski, G; Young, A; Wåler, S M; Rölla, G

2004-10-01

Oral malodour is mainly a result of the production of volatile sulphur compounds (VSC). The present study was concerned with investigating the anti-VSC effect of insoluble pyrophosphates (PP) of zinc, copper(II) and tin(II). The hypothesis to be tested was that the sulphide anions produced when VSC are solubilized in water have a higher affinity for the respective metal ions than the PP anion. The anti-VSC effects of insoluble PP were compared with the corresponding soluble metal salts using three in vitro methods: saliva putrefaction; dialysis of a suspension of PP and saliva against water; and analysis of water containing hydrogen sulphide and methyl mercaptan gases, and gases in the headspace. The levels of VSC were analysed by gas chromatography in the first and third methods, and released metal ions were analysed by atomic absorption spectroscopy in the second. The results showed that: the insoluble metal PP inhibited VSC formation in saliva by 99-100%; under dialysis, only minute amounts of metal ions are released from the combination of PP and saliva; and the PP lost their metal cations in water containing dissolved gases and inhibited VSC formation. Hence, the results support the experimental hypothesis. Sulphide ions are obviously very strong ligands for these metal ions.

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 ...

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

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

A natural macroalgae consortium for biosorption of copper from aqueous solution: Optimization, modeling and design studies.

PubMed

Deniz, Fatih; Ersanli, Elif Tezel

2018-03-21

In this study, the capacity of a natural macroalgae consortium consisting of Chaetomorpha sp., Polysiphonia sp., Ulva sp. and Cystoseira sp. species for the removal of copper ions from aqueous environment was investigated at different operating conditions, such as solution pH, copper ion concentration and contact time. These environmental parameters affecting the biosorption process were optimized on the basis of batch experiments. The experimentally obtained data for the biosorption of copper ions onto the macroalgae-based biosorbent were modeled using the isotherm models of Freundlich, Langmuir, Sips and Dubinin-Radushkevich and the kinetic models of pseudo-first-order, pseudo-second-order, Elovich and Weber and Morris. The pseudo-first-order and Sips equations were the most suitable models to describe the copper biosorption from aqueous solution. The thermodynamic data revealed the feasibility, spontaneity and physical nature of biosorption process. Based on the data of Sips isotherm model, the biosorption capacity of biosorbent for copper ions was calculated as 105.370 mg g -1 under the optimum operating conditions. A single-stage batch biosorption system was developed to predict the real-scale-based copper removal performance of biosorbent. The results of this investigation showed the potential utility of macroalgae consortium for the biosorption of copper ions from aqueous medium.

Mechanistic studies of copper(II)-aminoglycoside mediated DNA damage and magnesium catalyzed nuclease activity of hammerhead ribozyme

NASA Astrophysics Data System (ADS)

Patwardhan, Anjali A.

The antibacterial activity of aminoglycosides stems from their high affinity binding to the 16S rRNA in bacteria resulting in inhibition of protein synthesis. Used to treat acute bacterial infections these antibiotics have limited applications due to their high dosage requirements and the emergence of resistant strains. We have synthesized and characterized Cu(II) derivatives of the aminoglycosides, kanamycin A, tobramycin, neamine, kanamycin B, neomycin B, and paromomycin. The first three exhibit preferential and tight binding to Cu(II) as against neomycin B and kanamycin B and paromomycin. EPR of frozen solutions and UV-visible spectroscopy suggest a change in geometry around the Cu(II) but the stabilities of the complexes in water differ. These copper derivatives efficiently cleave plasmid DNA at micromolar concentrations (hydrolytic) and at nanomolar concentrations in the presence co-reactants like hydrogen peroxide or ascorbic acid. Hydrolysis is multi turnover and exhibits Michelis-Menten kinetics with enzyme-like behavior whereas oxidative cleavage is highly specific with C-4' H abstraction resulting in characteristic base propenal and nucleotide base products. Hydroxyl radicals generated are copper based and are generated in close proximity of the substrate. Hammerhead ribozymes are selectively hydrolyzed in the presence of divalent ions with Mg2+ being the metal ion of choice in vivo . Our studies with complex ions like cobalt hexaammine and fac-triamminetriaquochromium(III) establish outer sphere interactions of Mg2+ with the hammerhead in the catalytic site. There are two sets of sites, one structural and one catalytic. Complex ions in the catalytic site and divalent ions in the structural site result in a slow but active hammerhead ribozyme suggesting that the complex ions are not inhibitory, contrary to what was suggested previously.

An Angular Overlap Model for Cu(II) Ion in the AMOEBA Polarizable Force Field

PubMed Central

Xiang, Jin Yu; Ponder, Jay W.

2014-01-01

An extensible polarizable force field for transition metal ion was developed based on AMOEBA and the angular overlap model (AOM) with consistent treatment of electrostatics for all atoms. Parameters were obtained by fitting molecular mechanics (MM) energies to various ab initio gas-phase calculations. The results of parameterization were presented for copper (II) ion ligated to water and model fragments of amino acid residues involved in the copper binding sites of type 1 copper proteins. Molecular dynamics (MD) simulations were performed on aqueous copper (II) ion at various temperatures, as well as plastocyanin (1AG6) and azurin (1DYZ). Results demonstrated that the AMOEBA-AOM significantly improves the accuracy of classical MM in a number of test cases when compared to ab initio calculations. The Jahn-Teller distortion for hexa-aqua copper (II) complex was handled automatically without specifically designating axial and in-plane ligands. Analyses of MD trajectories resulted in a 6-coordination first solvation shell for aqueous copper (II) ion and a 1.8ns average residence time of water molecules. The ensemble average geometries of 1AG6 and 1DYZ copper binding sites were in general agreement with X-ray and previous computational studies. PMID:25045338

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

Development of a new passive sampler based on diffusive milligel beads for copper analysis in water.

PubMed

Perez, M; Reynaud, S; Lespes, G; Potin-Gautier, M; Mignard, E; Chéry, P; Schaumlöffel, D; Grassl, B

2015-08-26

A new passive sampler was designed and characterized for the determination of free copper ion (Cu(2+)) concentration in aqueous solution. Each sampling device was composed of a set of about 30 diffusive milligel (DMG) beads. Milligel beads with incorporated cation exchange resin (Chelex) particles were synthetized using an adapted droplet-based millifluidic process. Beads were assumed to be prolate spheroids, with a diameter of 1.6 mm and an anisotropic factor of 1.4. The milligel was controlled in chemical composition of hydrogel (monomer, cross-linker, initiator and Chelex concentration) and characterized in pore size. Two types of sampling devices were developed containing 7.5% and 15% of Chelex, respectively, and 6 nm pore size. The kinetic curves obtained demonstrated the accumulation of copper in the DMG according to the process described in the literature as absorption (and/or adsorption) and release following the Fick's first law of diffusion. For their use in water monitoring, the typical physico-chemical characteristics of the samplers, i.e. the mass-transfer coefficient (k0) and the sampler-water partition coefficient (Ksw), were determined based on a static exposure design. In order to determine the copper concentration in the samplers after their exposure, a method using DMG bead digestion combined to Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP-AES) analysis was developed and optimized. The DMG devices proved to be capable to absorb free copper ions from an aqueous solution, which could be accurately quantified with a mean recovery of 99% and a repeatability of 7% (mean relative uncertainty). Copyright © 2015 Elsevier B.V. All rights reserved.

Cu(I)/Cu(II) mixed-valence surface complexes of S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dibutyldithiocarbamate: Hydrophobic mechanism to malachite flotation.

PubMed

Liu, Sheng; Zhong, Hong; Liu, Guangyi; Xu, Zhenghe

2018-02-15

Hydroxamate and sulfhydryl surfactants are effective collectors for flotation of copper minerals. The combination application of hydroxamate and sulfhydryl collectors has been proved to be an effective approach for improving the flotation recovery of non-sulfide copper minerals. A surfactant owing both hydroxamate and dithiocarbamate groups might exhibit strong affinity to non-sulfide copper minerals through double sites adsorption, rendering an enhanced hydrophobization to non-sulfide copper minerals flotation. The flotation performance of S-[(2-hydroxyamino)-2-oxoethyl]- N,N-dibutyldithiocarbamate (HABTC) to malachite, calcite and quartz were first evaluated through systematic micro-flotation experiments. HABTC's hydrophobic mechanism to malachite was further investigated and analyzed by zeta potential, Fourier transform infrared spectroscopy (FTIR), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The micro-flotation results demonstrated HABTC was an excellent collector for malachite flotation and exhibited favorable selectivity for flotation separation of malachite from quartz or calcite under pH 8.5-10.3. Zeta potential and FTIR implied that HABTC might bond with the surface copper atoms of malachite, with releasing the H + ions of its hydroxamate group into pulp. ToF-SIMS provided clear evidences that the Cu-hydroxamate and Cu-dithiocarbamate groups were formed on malachite surfaces after HABTC adsorption. XPS revealed that Cu(I)/Cu(II) mixed-valence surface complexes of HABTC anchored on malachite through formation of Cu(I)S and Cu(II)O bonds, accompanying with reduction of partial surface Cu(II) to Cu(I). The Cu(I)/Cu(II) mixed-valence double chelating character and "chair"-shape N,N-dibutyldithiocarbamate hydrophobic group, resulting in an enhanced affinity and hydrophobization of HABTC to malachite flotation. Copyright © 2017 Elsevier Inc. All rights reserved.

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...

Stress- and sequence-dependent release into the culture medium of HIV-1 Nef produced in Saccharomyces cerevisiae.

PubMed

Macreadie, I G; Castelli, L A; Lucantoni, A; Azad, A A

1995-09-11

We have produced human immunodeficiency virus type 1 (HIV-1) Nef (a myristylated 206-amino-acid protein) in Saccharomyces cerevisaie and shown that, while Nef is normally found as a predominantly intracellular protein, amounts up to 40 micrograms/ml of Nef are also released into the extracellular medium during stress. By electrophoretic (SDS-PAGE) analysis the extracellular Nef is indistinguishable from intracellular Nef. Conditions of stress that lead to the release of Nef include elevated levels of copper or magnesium ions or growth at elevated temperatures. This release appears to be dependent upon the N-terminal sequences of Nef, including the presence of a myristylation site. Our observations concerning Nef release in yeast suggest new ways in which the behaviour of Nef should be examined in order to gain further insights into the development of AIDS. If the release of Nef is important in the development of AIDS, our work reveals that Nef-associated symptoms may be reduced or delayed by reducing stresses, such as fevers.

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 potential inhibitors of amylin oligomerization and fibril formation. Finally and more generally, this rapid technique opens the door for high-throughput screening of potential inhibitors of amyloid protein aggregation.« less

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

DOEpatents

Smith, Barbara F.; Robinson, Thomas W.

1997-01-01

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

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.

[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.

Determination of an organic-acid analog of DOC for use in copper toxicity studies on salmonids

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

MacRae, R.K.; Meyer, J.S.; Hansen, J.A.

1995-12-31

Concentrations of dissolved copper in streams draining mine sites often exceed concentrations shown to cause acute and chronic mortality in salmonids. However, toxicity and impaired behaviors may be modified by dissolved organic carbon (DOC) and other inorganic components present in the site water. The effects of DOC on copper speciation, and thus bioavailability and toxicity, were determined by titrating stream waters with copper, using a cupric ion-specific electrode to detect free copper concentrations. Effects of various competing cations (e.g., Ca{sup +2}, Co{sup +2}) on copper-DOC binding were also evaluated. Titration results were evaluated using Scatchard and non-linear regression analyses tomore » quantify the strength and capacity of copper-DOC binding. Inorganic speciation was determined using the geochemical model MINEQL{sup +}. Results of these titrations indicated the presence of two or three distinct copper binding components in site water DOC. Three commercially available organic acids where then chosen to mimic the binding characteristics of natural DOC. This DOC-analog was used successfully in fish toxicity studies to evaluate the influence of DOC on copper bioavailability. Geochemical models were developed to predict copper speciation in both laboratory test waters and site waters, for any typical combination of water chemistry parameters (pH, alkalinity, [DOC], etc.). A combined interpretation of fish toxicity and modeling results indicate that some DOC-bound copper was bioavailable.« less

Copper-Doped Bioactive Glass as Filler for PMMA-Based Bone Cements: Morphological, Mechanical, Reactivity, and Preliminary Antibacterial Characterization.

PubMed

Miola, Marta; Cochis, Andrea; Kumar, Ajay; Arciola, Carla Renata; Rimondini, Lia; Verné, Enrica

2018-06-06

To promote osteointegration and simultaneously limit bacterial contamination without using antibiotics, we designed innovative composite cements containing copper (Cu)-doped bioactive glass powders. Cu-doped glass powders were produced by a melt and quenching process, followed by an ion-exchange process in a Cu salt aqueous solution. Cu-doped glass was incorporated into commercial polymethyl methacrylate (PMMA)-based cements with different viscosities. The realized composites were characterized in terms of morphology, composition, leaching ability, bioactivity, mechanical, and antibacterial properties. Glass powders appeared well distributed and exposed on the PMMA surface. Composite cements showed good bioactivity, evidencing hydroxyapatite precipitation on the sample surfaces after seven days of immersion in simulated body fluid. The leaching test demonstrated that composite cements released a significant amount of copper, with a noticeable antibacterial effect toward Staphylococcus epidermidis strain. Thus, the proposed materials represent an innovative and multifunctional tool for orthopedic prostheses fixation, temporary prostheses, and spinal surgery.

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.

Ceruloplasmin and cardiovascular disease

NASA Technical Reports Server (NTRS)

Fox, P. L.; Mazumder, B.; Ehrenwald, E.; Mukhopadhyay, C. K.

2000-01-01

Transition metal ion-mediated oxidation is a commonly used model system for studies of the chemical, structural, and functional modifications of low-density lipoprotein (LDL). The physiological relevance of studies using free metal ions is unclear and has led to an exploration of free metal ion-independent mechanisms of oxidation. We and others have investigated the role of human ceruloplasmin (Cp) in oxidative processes because it the principal copper-containing protein in serum. There is an abundance of epidemiological data that suggests that serum Cp may be an important risk factor predicting myocardial infarction and cardiovascular disease. Biochemical studies have shown that Cp is a potent catalyst of LDL oxidation in vitro. The pro-oxidant activity of Cp requires an intact structure, and a single copper atom at the surface of the protein, near His(426), is required for LDL oxidation. Under conditions where inhibitory protein (such as albumin) is present, LDL oxidation by Cp is optimal in the presence of superoxide, which reduces the surface copper atom of Cp. Cultured vascular endothelial and smooth muscle cells also oxidize LDL in the presence of Cp. Superoxide release by these cells is a critical factor regulating the rate of oxidation. Cultured monocytic cells, when activated by zymosan, can oxidize LDL, but these cells are unique in their secretion of Cp. Inhibitor studies using Cp-specific antibodies and antisense oligonucleotides show that Cp is a major contributor to LDL oxidation by these cells. The role of Cp in lipoprotein oxidation and atherosclerotic lesion progression in vivo has not been directly assessed and is an important area for future studies.

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

Long-Term Behavior of Simulated Partial Lead Service Line Replacements

PubMed Central

St. Clair, Justin; Cartier, Clement; Triantafyllidou, Simoni; Clark, Brandi; Edwards, Marc

2016-01-01

Abstract In this 48-month pilot study, long-term impacts of copper:lead galvanic connections on lead release to water were assessed without confounding differences in pipe exposure prehistory or disturbances arising from cutting lead pipe. Lead release was tracked from three lead service line configurations, including (1) 100% lead, (2) traditional partial replacement with 50% copper upstream of 50% lead, and (3) 50% lead upstream of 50% copper as a function of flow rate, connection types, and sampling methodologies. Elevated lead from galvanic corrosion worsened with time, with 140% more lead release from configurations representing traditional partial replacement configurations at 14 months compared to earlier data in the first 8 months. Even when sampled consistently at moderate flow rate (8 LPM) and collecting all water passing through service lines, conditions representing traditional partial service line configurations were significantly worse (≈40%) when compared to 100% lead pipe. If sampled at a high flow rate (32 LPM) and collecting 2 L samples from service lines, 100% of samples collected from traditional partial replacement configurations exceeded thresholds posing an acute health risk versus a 0% risk for samples from 100% lead pipe. Temporary removal of lead accumulations near Pb:Cu junctions and lead deposits from other downstream plastic pipes reduced risk of partial replacements relative to that observed for 100% lead. When typical brass compression couplings were used to connect prepassivated lead pipes, lead release spiked up to 10 times higher, confirming prior concerns raised at bench and field scale regarding adverse impacts of crevices and service line disturbances on lead release. To quantify semirandom particulate lead release from service lines in future research, whole-house filters have many advantages compared to other approaches. PMID:26989344

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

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.

Development and evaluation of Ca(+ 2) ion cross-linked carboxymethyl xanthan gum tablet prepared by wet granulation technique.

PubMed

Maity, Siddhartha; Sa, Biswanath

2014-08-01

The objective of this work was to study the release behavior of prednisolone from calcium-cross-linked carboxymethyl xanthan gum (CMXG) tablets in dissolution medium having different pH values prevailing in the gastrointestinal lumen. Xanthan gum (XG) was derivatized to CMXG which was then cross-linked in situ with Ca(+2) ion during wet massing step of tablet preparation. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry studies did not show any drug-polymer interaction although the drug underwent solid-state transformation during compression as evident from X-ray diffraction analysis. In vitro release study demonstrated that increase in the amount of Ca(+2) ion decreased the drug release, and beyond a certain amount, the drug release increased. While increase in both drug load and tablet crushing strength decreased the drug release, increase in exposure time in acid solution of pH 1.2 increased the overall release of the drug. The mechanism of drug release was non-Fickian/anomalous. The results indicated that variation in the amount of Ca(+2) ion can modulate the drug release from CMXG matrix tablets as needed.

Effect of Cu content on microstructure, mechanical and anti-fouling properties of TiSiN-Cu coating deposited by multi-arc ion plating

NASA Astrophysics Data System (ADS)

Bai, Xuebing; Li, Jinlong; Zhu, Lihui; Wang, Liping

2018-01-01

The copper-doped TiSiN coatings were deposited on 316L stainless steel by reactive co-sputtering in multi-arc ion plating. The surface morphology and structure of the coating were analyzed by scanning electron microcopies, X-ray diffraction and X-ray photoelectron spectroscopy. The hardness was tested using Nano-indentation. The influence of the copper content in the coatings on the structure and mechanical properties of TiSiN-Cu coatings was investigated. Antifouling behaviors of the coatings were evaluated by analyzing adhesion and propagation of P. tricornutum, N. closterium, and Chlorella sp. The TiSiN-Cu coatings had a unique structure of amorphous Si3N4 and nanocrystalline nc-TiN/nc-Cu. The Cu-TiSiN coatings can inhibit effectively attachment and colonization of the algae on the surface. When the copper content increases from 6.75 at.% to 25.15 at.%, the coatings show an obvious decrease in hardness, significantly increase in the surface roughness and greatly weaken in antifouling properties. When the copper content is 6.75 at.%, the coating has the highest hardness with 30 GPa, and the best reduction ratio with 89%, 93% and 57% attachment of P. triceratium, N. closterium and Chlorella sp., respectively. The TiSiN-Cu coating with a copper dosage of 6.75 at.% has the excellent mechanical properties and capability of killing effectively microalgae.

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...

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

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.

[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 and 14.61 kW x h x kg(-1), respectively. The deposited copper on the cathode material was fascicularly distributed and no oxygen was detected.

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.

Analysis of antioxidants in insulation cladding of copper wire: a comparison of different mass spectrometric techniques (ESI-IT, MALDI-RTOF and RTOF-SIMS).

PubMed

Schnöller, Johannes; Pittenauer, Ernst; Hutter, Herbert; Allmaier, Günter

2009-12-01

Commercial copper wire and its polymer insulation cladding was investigated for the presence of three synthetic antioxidants (ADK STAB AO412S, Irganox 1010 and Irganox MD 1024) by three different mass spectrometric techniques including electrospray ionization-ion trap-mass spectrometry (ESI-IT-MS), matrix-assisted laser desorption/ionization reflectron time-of-flight (TOF) mass spectrometry (MALDI-RTOF-MS) and reflectron TOF secondary ion mass spectrometry (RTOF-SIMS). The samples were analyzed either directly without any treatment (RTOF-SIMS) or after a simple liquid/liquid extraction step (ESI-IT-MS, MALDI-RTOF-MS and RTOF-SIMS). Direct analysis of the copper wire itself or of the insulation cladding by RTOF-SIMS allowed the detection of at least two of the three antioxidants but at rather low sensitivity as molecular radical cations and with fairly strong fragmentation (due to the highly energetic ion beam of the primary ion gun). ESI-IT- and MALDI-RTOF-MS-generated abundant protonated and/or cationized molecules (ammoniated or sodiated) from the liquid/liquid extract. Only ESI-IT-MS allowed simultaneous detection of all three analytes in the extract of insulation claddings. The latter two so-called 'soft' desorption/ionization techniques exhibited intense fragmentation only by applying low-energy collision-induced dissociation (CID) tandem MS on a multistage ion trap-instrument and high-energy CID on a tandem TOF-instrument (TOF/RTOF), respectively. Strong differences in the fragmentation behavior of the three analytes could be observed between the different CID spectra obtained from either the IT-instrument (collision energy in the very low eV range) or the TOF/RTOF-instrument (collision energy 20 keV), but both delivered important structural information. Copyright 2009 John Wiley & Sons, Ltd.

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.

Nanocomposite scaffolds with tunable mechanical and degradation capabilities: co-delivery of bioactive agents for bone tissue engineering.

PubMed

Cattalini, Juan P; Roether, Judith; Hoppe, Alexander; Pishbin, Fatemeh; Haro Durand, Luis; Gorustovich, Alejandro; Boccaccini, Aldo R; Lucangioli, Silvia; Mouriño, Viviana

2016-10-21

Novel multifunctional nanocomposite scaffolds made of nanobioactive glass and alginate crosslinked with therapeutic ions such as calcium and copper were developed for delivering therapeutic agents, in a highly controlled and sustainable manner, for bone tissue engineering. Alendronate, a well-known antiresorptive agent, was formulated into microspheres under optimized conditions and effectively loaded within the novel multifunctional scaffolds with a high encapsulation percentage. The size of the cation used for the alginate crosslinking impacted directly on porosity and viscoelastic properties, and thus, on the degradation rate and the release profile of copper, calcium and alendronate. According to this, even though highly porous structures were created with suitable pore sizes for cell ingrowth and vascularization in both cases, copper-crosslinked scaffolds showed higher values of porosity, elastic modulus, degradation rate and the amount of copper and alendronate released, when compared with calcium-crosslinked scaffolds. In addition, in all cases, the scaffolds showed bioactivity and mechanical properties close to the endogenous trabecular bone tissue in terms of viscoelasticity. Furthermore, the scaffolds showed osteogenic and angiogenic properties on bone and endothelial cells, respectively, and the extracts of the biomaterials used promoted the formation of blood vessels in an ex vivo model. These new bioactive nanocomposite scaffolds represent an exciting new class of therapeutic cell delivery carrier with tunable mechanical and degradation properties; potentially useful in the controlled and sustainable delivery of therapeutic agents with active roles in bone formation and angiogenesis, as well as in the support of cell proliferation and osteogenesis for bone tissue engineering.

The structure of molten CuCl: Reverse Monte Carlo modeling with high-energy X-ray diffraction data and molecular dynamics of a polarizable ion model

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

Alcaraz, Olga; Trullàs, Joaquim, E-mail: quim.trullas@upc.edu; Tahara, Shuta

2016-09-07

The results of the structural properties of molten copper chloride are reported from high-energy X-ray diffraction measurements, reverse Monte Carlo modeling method, and molecular dynamics simulations using a polarizable ion model. The simulated X-ray structure factor reproduces all trends observed experimentally, in particular the shoulder at around 1 Å{sup −1} related to intermediate range ordering, as well as the partial copper-copper correlations from the reverse Monte Carlo modeling, which cannot be reproduced by using a simple rigid ion model. It is shown that the shoulder comes from intermediate range copper-copper correlations caused by the polarized chlorides.

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

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.

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.

A HiPIMS plasma source with a magnetic nozzle that accelerates ions: application in a thruster

NASA Astrophysics Data System (ADS)

Bathgate, Stephen N.; Ganesan, Rajesh; Bilek, Marcela M. M.; McKenzie, David R.

2017-01-01

We demonstrate a solid fuel electrodeless ion thruster that uses a magnetic nozzle to collimate and accelerate copper ions produced by a high power impulse magnetron sputtering discharge (HiPIMS). The discharge is initiated using argon gas but in a practical device the consumption of argon could be minimised by exploiting the self-sputtering of copper. The ion fluence produced by the HiPIMS discharge was measured with a retarding field energy analyzer (RFEA) as a function of the magnetic field strength of the nozzle. The ion fraction of the copper was determined from the deposition rate of copper as a function of substrate bias and was found to exceed 87%. The ion fluence and ion energy increased in proportion with the magnetic field of the nozzle and the energy of the ions was found to follow a Maxwell-Boltzmann distribution with a directed velocity. The effectiveness of the magnetic nozzle in converting the randomized thermal motion of the ions into a jet was demonstrated from the energy distribution of the ions. The maximum ion exhaust velocity of at least 15.1 km/s, equivalent to a specific impulse of 1543 s was measured which is comparable to existing Hall thrusters and exceeds that of Teflon pulsed plasma thrusters.

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.

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.

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…

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.

Will ethylene oxide sterilization influence the application of novel Cu/LDPE nanocomposite intrauterine devices?

PubMed

Xia, Xianping; Wang, Yun; Cai, Shuizhou; Xie, Changsheng; Zhu, Changhong

2009-01-01

Copper/low-density polyethylene (Cu/LDPE) nanocomposite intrauterine device (IUD) is an implanted medicinal device that must be sterilized before use. Sterilization processes act either chemically or physically, leading to a lethal change in the structure or function of organic macromolecules in microorganisms. Given the nature of their action, sterilization might also attack the macromolecules of polymers by the same mechanisms, resulting in changes in surface functional groups and in the internal structure of the polymer. If sterilization leads to changes in surface functional groups and in the internal structure of the LDPE matrix, which will influence the mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite IUDs, potential clinical application will be limited. Therefore, it is necessary to study the influence of ethylene oxide sterilization on the potential clinical application of novel Cu/LDPE nanocomposite IUDs. The influence of ethylene oxide sterilization on the internal structure, surface functional groups, mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite IUDs was studied using differential scanning calorimetry, attenuated total reflection Fourier transform infrared spectroscopy, tensile testing and absorbance measurement. Ethylene oxide sterilization did not have any influence on the internal structure, surface functional groups, mechanical property and cupric ions release rate of novel Cu/LDPE nanocomposite intrauterine devices. Ethylene oxide sterilization will not affect the potential application of novel Cu/LDPE nanocomposite IUDs.

Electrochemical behaviour of naked sub-nanometre sized copper clusters and effect of CO 2

DOE PAGES

Passalacqua, Rosalba; Parathoner, Siglinda; Centi, Gabriele; ...

2016-08-04

The study of the electrochemical behavior (in the presence of N 2 or CO 2) of size-controlled naked Cu 5 and Cu 20 nanoclusters, prepared using a combination of gas-phase cluster ion sources, mass spectrometry, and soft-landing techniques, evidences some relevant results regarding the redox behavior of these sub-nanometre sized copper particles and the effect of CO 2 on them. Cu 20 nanoclusters show anodic redox processes occurring at much lower potential with respect to Cu 5 nanoclusters, which behave relatively similar to much larger Cu particles. However, Cu 5 nanoclusters coordinate effectively CO 2 (hydrogen carbonate) in solution, differentmore » from Cu 20 nanoclusters and larger Cu particles. This effect, rather than the redox behavior, is apparently connected to the ability of Cu 5 nanoclusters to reduce CO 2 under cathodic conditions at low overpotential. In conclusion, although preliminary, these results provide rather exciting indications on the possibility of realizing low overpotential electrocatalytic conversion of CO 2.« less

Electrochemical behaviour of naked sub-nanometre sized copper clusters and effect of CO 2

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

Passalacqua, Rosalba; Parathoner, Siglinda; Centi, Gabriele

The study of the electrochemical behavior (in the presence of N 2 or CO 2) of size-controlled naked Cu 5 and Cu 20 nanoclusters, prepared using a combination of gas-phase cluster ion sources, mass spectrometry, and soft-landing techniques, evidences some relevant results regarding the redox behavior of these sub-nanometre sized copper particles and the effect of CO 2 on them. Cu 20 nanoclusters show anodic redox processes occurring at much lower potential with respect to Cu 5 nanoclusters, which behave relatively similar to much larger Cu particles. However, Cu 5 nanoclusters coordinate effectively CO 2 (hydrogen carbonate) in solution, differentmore » from Cu 20 nanoclusters and larger Cu particles. This effect, rather than the redox behavior, is apparently connected to the ability of Cu 5 nanoclusters to reduce CO 2 under cathodic conditions at low overpotential. In conclusion, although preliminary, these results provide rather exciting indications on the possibility of realizing low overpotential electrocatalytic conversion of CO 2.« less

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.

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.

Interactions between copper(II) and DOM in the urban stormwater runoff: modeling and characterizations.

PubMed

Zhao, Chen; Wang, Chong-Chen; Li, Jun-Qi; Wang, Peng; Ou, Jia-Qi; Cui, Jing-Rui

2018-01-01

Dissolved organic matter (DOM) can strongly interact with both organic and inorganic contaminants to influence their transportation, transformation, bioavailability, toxicity and even their ultimate fate. Within this work, DOM was extracted from urban stormwater runoff samples collected from a regular sampling site of a typical residential area in Beijing, China. Copper(II) ions were selected as model to investigate the interactions between DOM and typical heavy metals. Both ultraviolet (UV) absorbance and fluorescence titration methods were introduced to determine the complex capacities (C L ) and conditional stability constants (log K M ) of bonding between DOM and copper (II) ions, which revealed that the values of C L were 85.62 and 87.23 μmol mg -1 and the log K M values were 5.37 and 5.48, respectively. The results suggested the successful complexation between DOM and copper(II) ions. Furthermore, morphology of the DOM binding to copper(II) ions was confirmed by both energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS), which can facilitate to clarify the corresponding mechanism. The Cu 2p 3/2 peak at 933.7 eV and the characteristic shake-up peaks of Cu-O were found in the XPS spectra, implying that copper(II) ions might coordinate with hydroxyl (aliphatic or phenolic) or carboxyl groups. With these profitable results, it can be concluded that DOM in urban stormwater runoff has a strong binding affinity with copper(II) ions, which may further lead to potentially significant influence on their migration and transformation.

The reduced bioavailability of copper by nano-TiO₂ attenuates the toxicity to Microcystis aeruginosa.

PubMed

Chen, Jinyuan; Qian, Yi; Li, Herong; Cheng, Yanhong; Zhao, Meirong

2015-08-01

Nano-TiO2 is a widely applied nanoparticle (NPs) and co-exists with other pollutants such as heavy metals in aquatic environments. However, minimal knowledge is available concerning the ecological risk of these mixtures. Our study reported that at no toxic effect concentrations of TiO2 nanoparticles (5 mg/L), the toxicity of Cu ions to the algae Microcystis aeruginosa was significantly attenuated by TiO2 nanoparticles. Specifically, the concentration of photosynthetic pigments (i.e., concentration of Chla) increased 37% when comparing only Cu ions treated and the nano-TiO2-Cu co-incubation. The levels of phycocyanin (PC), allophycocyanin (APC), phycoerythrin (PE), and phycobiliprotein (PBPs) were also recovered at levels ranging from 23 to 35% after 72 h. For oxidative indexes, the decreased activities of the superoxide dismutase (SOD), peroxidase (POD) content, and malondialdehyde (MDA) with the existence of nano-TiO2 displayed a lower level compared to Cu ions treatment only at 24 and 48 h. This toxicity attenuation can be confirmed by subcellular structures because the impairment to cellular membranes and organelles reduced with the presence of nano-TiO2. The potential mechanisms of the antagonism between the nano-TiO2 and Cu ions can be partially attributed to the sorption of copper onto TiO2 nanoparticles, which fitted the Freundlich isotherm (coefficient = 0.967). The decreased bioavailability of Cu ions protected algae cells from being attacked by free Cu ions. Given the abundance of released nanoparticles and unique physicochemical property of nanoparticles, our results elucidated the ecosafety of nanoparticles and co-substrates in aquatic systems.

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

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

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 potential inhibitors of amylin oligomerization and fibril formation. Finally and more generally, this rapid technique opens the door for high-throughput screening of potential inhibitors of amyloid protein aggregation.« less

Complete genome sequence of Acidihalobacter prosperus strain F5, an extremely acidophilic, iron- and sulfur-oxidizing halophile with potential industrial applicability in saline water bioleaching of chalcopyrite.

PubMed

Khaleque, Himel N; Corbett, Melissa K; Ramsay, Joshua P; Kaksonen, Anna H; Boxall, Naomi J; Watkin, Elizabeth L J

2017-11-20

Successful process development for the bioleaching of mineral ores, particularly the refractory copper sulfide ore chalcopyrite, remains a challenge in regions where freshwater is scarce and source water contains high concentrations of chloride ion. In this study, a pure isolate of Acidihalobacter prosperus strain F5 was characterized for its ability to leach base metals from sulfide ores (pyrite, chalcopyrite and pentlandite) at increasing chloride ion concentrations. F5 successfully released base metals from ores including pyrite and pentlandite at up to 30gL -1 chloride ion and chalcopyrite up to 18gL -1 chloride ion. In order to understand the genetic mechanisms of tolerance to high acid, saline and heavy metal stress the genome of F5 was sequenced and analysed. As well as being the first strain of Ac. prosperus to be isolated from Australia it is also the first complete genome of the Ac. prosperus species to be sequenced. The F5 genome contains genes involved in the biosynthesis of compatible solutes and genes encoding monovalent cation/proton antiporters and heavy metal transporters which could explain its abilities to tolerate high salinity, acidity and heavy metal stress. Genome analysis also confirmed the presence of genes involved in copper tolerance. The study demonstrates the potential biotechnological applicability of Ac. prosperus strain F5 for saline water bioleaching of mineral ores. Copyright © 2017 Elsevier B.V. All rights reserved.

Phenotypic Characterization of a copA Mutant of Neisseria gonorrhoeae Identifies a Link between Copper and Nitrosative Stress

PubMed Central

Djoko, Karrera Y.; Franiek, Jessica A.; Edwards, Jennifer L.; Falsetta, Megan L.; Kidd, Stephen P.; Potter, Adam J.; Chen, Nathan H.; Apicella, Michael A.; Jennings, Michael P.

2012-01-01

NGO0579 is annotated copA in the Neisseria gonorrhoeae chromosome, suggesting that it encodes a cation-transporting ATPase specific for copper ions. Compared to wild-type cells, a copA mutant was more sensitive to killing by copper ions but not to other transition metals. The mutant also accumulated a greater amount of copper, consistent with the predicted role of CopA as a copper efflux pump. The copA mutant showed a reduced ability to invade and survive within human cervical epithelial cells, although its ability to form a biofilm on the surface of these cells was not significantly different from that of the wild type. In the presence of copper, the copA mutant exhibited increased sensitivity to killing by nitrite or nitric oxide. Therefore, we concluded that copper ion efflux catalyzed by CopA is linked to the nitrosative stress defense system of Neisseria gonorrhoeae. These observations suggest that copper may exert its effects as an antibacterial agent in the innate immune system via an interaction with reactive nitrogen species. PMID:22184419

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...

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.

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.

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.

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…

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.

Poly(ethylene imine)-based granular sorbents by a new process of templated gel-filling. High capacity and selectivity of copper sorption in acidic and alkaline media

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

Chanda, M.; Rempel, G.L.

A new process has been developed for making granular gel-type sorbents from chelating resins using metal ion as template. Named as templated gel-filling, the process uses the chosen metal as templating host ion on high-surface-area silica to build a templated gel layer from a solution of the chelating resin in a suitable solvent in which the resin is soluble but its metal complex is insoluble. After cross-linking the templated gel layer, the silica support is removed by alkali to produce a hollow shell of the templated gel. The shells are then soaked in a concentrated aqueous solution of the samemore » metal ion and suspended in the same resin solution to afford gel-filling. The shells thus filled with metal-templated gel are treated with cross-linking agent, followed by acid to remove the template ion and activate the resin for metal sorption. Poly(ethyleneimine) and its partially ethylated derivative have been used to produce granular gel-type sorbents by this process, with Cu(II) as the template ion. These sorbents are found to offer high capacity and selectivity for copper over nickel, cobalt, and zinc in both acidic and alkaline media. Containing a relatively high fraction of imbibed water, the sorbents exhibit markedly enhanced rate behavior, in both sorption and stripping.« less

Investigation of MeV-Cu implantation and channeling effects into porous silicon formation

NASA Astrophysics Data System (ADS)

Ahmad, M.; Naddaf, M.

2011-11-01

P-type (1 1 1) silicon wafers were implanted by copper ions (2.5 MeV) in channeling and random directions using ion beam accelerator of the Atomic Energy Commission of Syria (AECS). The effect of implantation direction on formation process of porous silicon (PS) using electrochemical etching method has been investigated using scanning electron microscope (SEM) and photoluminescence (PL) techniques. SEM observations revealed that the size, shape and density of the formed pores are highly affected by the direction of beam implantation. This in turn is seen to influence the PL behavior of the PS.

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.

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.

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

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.

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.

Influence of the microstructure on electrochemical corrosion and nickel release in NiTi orthodontic archwires.

PubMed

Briceño, J; Romeu, A; Espinar, E; Llamas, J M; Gil, F J

2013-12-01

The aim of this work was to determine the influence of the present phases and the chemical composition on the corrosion behavior and the nickel ion release of the NiTi orthodontic archwires. Eight Ni-Ti archwires from six commercial brands, in the as-received condition, were studied. The chemical composition, roughness, microstructure and the proportion of the phases as well as the corrosion behavior were analyzed for each archwire. The nickel ion release was characterized in artificial saliva immersion settings ranging up to 4 weeks. The results show that the presence of the martensitic phase improves corrosion resistance and significantly decreases Ni release into exterior medium in comparison with the austenitic specimens. In spite of the partial loss of superelasticity produced in the martensitic phase, it could be of great interest for biomedical applications, as it could minimize sensitization and allergies and improve biocompatibility and corrosion resistance of NiTi shape memory alloys. © 2013.

Roofing Materials Assessment: Investigation of Five Metals in Runoff from Roofing Materials.

PubMed

Winters, Nancy; Granuke, Kyle; McCall, Melissa

2015-09-01

To assess the contribution of five toxic metals from new roofing materials to stormwater, runoff was collected from 14 types of roofing materials and controls during 20 rain events and analyzed for metals. Many of the new roofing materials evaluated did not show elevated metals concentrations in the runoff. Runoff from several other roofing materials was significantly higher than the controls for arsenic, copper, and zinc. Notably, treated wood shakes released arsenic and copper, copper roofing released copper, PVC roofing released arsenic, and Zincalume® and EPDM roofing released zinc. For the runoff from some of the roofing materials, metals concentrations decreased significantly over an approximately one-year period of aging. Metals concentrations in runoff were demonstrated to depend on a number of factors, such as roofing materials, age of the materials, and climatic conditions. Thus, application of runoff concentrations from roofing materials to estimate basin-wide releases should be undertaken cautiously.

Differential affinity of BsSCO for Cu(II) and Cu(I) suggests a redox role in copper transfer to the Cu(A) center of cytochrome c oxidase.

PubMed

Hill, Bruce C; Andrews, Diann

2012-06-01

SCO (synthesis of cytochrome c oxidase) proteins are involved in the assembly of the respiratory chain enzyme cytochrome c oxidase acting to assist in the assembly of the Cu(A) center contained within subunit II of the oxidase complex. The Cu(A) center receives electrons from the reductive substrate ferrocytochrome c, and passes them on to the cytochrome a center. Cytochrome a feeds electrons to the oxygen reaction site composed of cytochrome a(3) and Cu(B). Cu(A) consists of two copper ions positioned within bonding distance and ligated by two histidine side chains, one methionine, a backbone carbonyl and two bridging cysteine residues. The complex structure and redox capacity of Cu(A) present a potential assembly challenge. SCO proteins are members of the thioredoxin family which led to the early suggestion of a disulfide exchange function for SCO in Cu(A) assembly, whereas the copper binding capacity of the Bacillus subtilis version of SCO (i.e., BsSCO) suggests a direct role for SCO proteins in copper transfer. We have characterized redox and copper exchange properties of apo- and metalated-BsSCO. The release of copper (II) from its complex with BsSCO is best achieved by reducing it to Cu(I). We propose a mechanism involving both disulfide and copper exchange between BsSCO and the apo-Cu(A) site. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes. Copyright © 2011 Elsevier B.V. All rights reserved.

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.

Antimicrobial properties of zeolite-X and zeolite-A ion-exchanged with silver, copper, and zinc against a broad range of microorganisms.

PubMed

Demirci, Selami; Ustaoğlu, Zeynep; Yılmazer, Gonca Altın; Sahin, Fikrettin; Baç, Nurcan

2014-02-01

Zeolites are nanoporous alumina silicates composed of silicon, aluminum, and oxygen in a framework with cations, water within pores. Their cation contents can be exchanged with monovalent or divalent ions. In the present study, the antimicrobial (antibacterial, anticandidal, and antifungal) properties of zeolite type X and A, with different Al/Si ratio, ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions were investigated individually. The study presents the synthesis and manufacture of four different zeolite types characterized by scanning electron microscopy and X-ray diffraction. The ion loading capacity of the zeolites was examined and compared with the antimicrobial characteristics against a broad range of microorganisms including bacteria, yeast, and mold. It was observed that Ag(+) ion-loaded zeolites exhibited more antibacterial activity with respect to other metal ion-embedded zeolite samples. The results clearly support that various synthetic zeolites can be ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions to acquire antimicrobial properties or ion-releasing characteristics to provide prolonged or stronger activity. The current study suggested that zeolite formulations could be combined with various materials used in manufacturing medical devices, surfaces, textiles, or household items where antimicrobial properties are required.

Kinetic studies of adsorption of Cu (II) from aqueous solution by coriander seeds (Coriandrum Sativum)

NASA Astrophysics Data System (ADS)

Kadiri, L.; Lebkiri, A.; Rifi, E. H.; Ouass, A.; Essaadaoui, Y.; Lebkiri, I.; Hamad, H.

2018-05-01

The adsorption of copper ions Cu2+ by Coriandrum Sativum seeds (CSS) from aqueous solution was studied in order to highlight the importance of coriander seeds as a potential tool in the treatment of wastewaters containing heavy metals. The kinetic studies of adsorption of Cu (II) were discussed using the spectroscopic technique "Inducting Coupled Plasma" (ICP). The effects of initial copper ion concentration and contact time were determined. All results show that coriander seeds have, over their culinary and medicinal benefits, a significant adsorbent power of copper ions.

Chemically modified Moringa oleifera seed husks as low cost adsorbent for removal of copper from aqueous solution

NASA Astrophysics Data System (ADS)

Ghafar, Faridah; Mohtar, Aminullah; Sapawe, Norzahir; Hadi, Norulakmal Nor; Salleh, Marmy Roshaidah Mohd

2017-12-01

Moringa oleifera husks (MOH) are an agricultural byproduct that may have potential as adsorbent for removal of heavy metal ions in wastewater such as copper (Cu2+). The release of Cu2+ to the environment by the mining and electroplating industries cause a major problem because it is toxic and can cause liver and kidney problems. Hence, it is important to remove copper before the wastewater can be discharged to the environment. In order to increase the adsorption capacity, the MOH was chemically modified using citric acid. The raw and modified MOH were analyzed using Fourier Transform Infra-Red (FTIR) for identification of functional groups present at the adsorbent surface. The adsorption study was carried out using the batch technique in water bath shaker investigating different parameters; adsorbent dosage (30 - 70 g/L), initial concentration of copper (30 - 150 mg/L), contact time (2 - 90 min), temperature (27 - 60 °C) at constant agitation of 100 rpm. The concentrations of copper in aqueous solution before and after the adsorption process was analyzed using Atomic Absorption Spectrum (AAS). The highest percentage removal of copper was found at 10g/L of adsorbent dosage with 30 mg/L of initial concentration and temperature 30 °C. It was also observed that the adsorption of copper by MOH was approaching to equilibrium at 60 min of reaction time. From the FTIR analysis, it was found that the MOH contains hydroxyl, carboxyl and amine groups. The high adsorption capacity of modified MOH to remove copper from aqueous solution makes it preferable and attractive alternative to commercial adsorbent.

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

Dynamic High-Pressure Behavior of Hierarchical Heterogeneous Geological Materials

DTIC Science & Technology

2016-04-01

sandwiched between two 25µm FEP copolymer layers attached to the copper driver plate . The total package thickness with thin-film epoxy on all bonding...public release. 3 OUTLINE Page # ABSTRACT 2 1. BACKGROUND 4 2. CHARACTERISTICS OF SAND INVESTIGATED 8 3. PLATE ...constituents, phases, inter-phase boundaries ; distributions in shock states; as well as the structural evolutions which can result in strain

BioMetals: a historical and personal perspective.

PubMed

Silver, Simon

2011-06-01

Understanding of BioMetals developed basically from a starting point about 60 years ago to current mechanistic understanding of the biological behavior of many metal ions from protein structural and functional studies. Figure 1 shows a Biochemical Periodic Table, element by element, with requirements, roles and biochemistry of the specific ions indicated. With few exceptions, the biology is of the ions formed and not of the elemental state of each. Early BioMetals efforts defined nutritional growth needs for animals, plants and microbes for inorganic "macro-nutrients" such as magnesium, calcium, potassium, sodium, and phosphate and of "micronutrients" such as copper, iron, manganese and zinc. Surprises came early with regard to microbes, for example the finding that Escherichia coli (then and now the standard microbial model) grows happily in the apparent total absence of calcium, sodium, and chloride, which are certainly major animal nutrients. Some elements such as mercury and arsenic are never required by living cells, but are always toxic, often at very low levels. Therefore, the division into nutrient elements and toxic elements came soon. For most inorganic nutrients, excessive amounts can be toxic as well, for example for copper and iron.

Preparation of Cotton-Wool-Like Poly(lactic acid)-Based Composites Consisting of Core-Shell-Type Fibers

PubMed Central

Wang, Jian; Zhou, Pin; Obata, Akiko; Jones, Julian R.; Kasuga, Toshihiro

2015-01-01

In previous works, we reported the fabrication of cotton-wool-like composites consisting of siloxane-doped vaterite and poly(l-lactic acid) (SiVPCs). Various irregularly shaped bone voids can be filled with the composite, which effectively supplies calcium and silicate ions, enhancing the bone formation by stimulating the cells. The composites, however, were brittle and showed an initial burst release of ions. In the present work, to improve the mechanical flexibility and ion release, the composite fiber was coated with a soft, thin layer consisting of poly(d,l-lactic-co-glycolic acid) (PLGA). A coaxial electrospinning technique was used to prepare a cotton-wool-like material comprising “core-shell”-type fibers with a diameter of ~12 µm. The fibers, which consisted of SiVPC coated with a ~2-µm-thick PLGA layer, were mechanically flexible; even under a uniaxial compressive load of 1.5 kPa, the cotton-wool-like material did not exhibit fracture of the fibers and, after removing the load, showed a ~60% recovery. In Tris buffer solution, the initial burst release of calcium and silicate ions from the “core-shell”-type fibers was effectively controlled, and the ions were slowly released after one day. Thus, the mechanical flexibility and ion-release behavior of the composites were drastically improved by the thin PLGA coating. PMID:28793691

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.

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...

Investigation of collision-induced dissociation products and structures of gas-phase [ M·GlyGlyHis-H]+ ( M = Fe, Ni, Cu, and Zn) complexes.

PubMed

Gannamani, Bharathi; Shin, Joong-Won

2017-02-01

Collision-induced dissociation is carried out for electrosprayed [Fe·GlyGlyHis-H] + , [Ni·GlyGlyHis-H] + , [Cu·GlyGlyHis-H] + , and [Zn·GlyGlyHis-H] + complexes. [Fe·GlyGlyHis-H] + , [Ni·GlyGlyHis-H] + , and [Zn·GlyGlyHis-H] + yield metal-bound peptide sequence ions and dehydrated ions as primary products, whereas [Cu·GlyGlyHis-H] + generates a more extensive series of metal-bound sequence ions and a product arising from the unusual loss of a formaldehyde moiety; dehydration is significantly suppressed for this complex. Density functional theory calculations show that the copper ion-deprotonated peptide binding energy is substantially higher than those in other complexes, suggesting that there is a correlation between ion-ligand binding energy and their fragmentation behavior.

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 phage could be endocytosed by cancer cells in culture.

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.

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

Silver nanoparticles in aquatic environments: Physiochemical behavior and antimicrobial mechanisms.

PubMed

Zhang, Chiqian; Hu, Zhiqiang; Deng, Baolin

2016-01-01

Nanosilver (silver nanoparticles or AgNPs) has unique physiochemical properties and strong antimicrobial activities. This paper provides a comprehensive review of the physicochemical behavior (e.g., dissolution and aggregation) and antimicrobial mechanisms of nanosilver in aquatic environments. The inconsistency in calculating the Gibbs free energy of formation of nanosilver [ΔGf(AgNPs)] in aquatic environments highlights the research needed to carefully determine the thermodynamic stability of nanosilver. The dissolutive release of silver ion (Ag(+)) in the literature is often described using a pseudo-first-order kinetics, but the fit is generally poor. This paper proposes a two-stage model that could better predict silver ion release kinetics. The theoretical analysis suggests that nanosilver dissolution could occur under anoxic conditions and that nanosilver may be sulfidized to form silver sulfide (Ag2S) under strict anaerobic conditions, but more investigation with carefully-designed experiments is required to confirm the analysis. Although silver ion release is likely the main antimicrobial mechanism of nanosilver, the contributions of (ion-free) AgNPs and reactive oxygen species (ROS) generation to the overall toxicity of nanosilver must not be neglected. Several research directions are proposed to better understand the dissolution kinetics of nanosilver and its antimicrobial mechanisms under various aquatic environmental conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cooperative binding modes of Cu(II) in prion protein

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Chisnell, Robin; Lu, Wenchang; Bernholc, Jerry

2007-03-01

The misfolding of the prion protein, PrP, is responsible for a group of neurodegenerative diseases including mad cow disease and Creutzfeldt-Jakob disease. It is known that the PrP can efficiently bind copper ions; four high-affinity binding sites located in the octarepeat region of PrP are now well known. Recent experiments suggest that at low copper concentrations new binding modes, in which one copper ion is shared between two or more binding sites, are possible. Using our hybrid Thomas-Fermi/DFT computational scheme, which is well suited for simulations of biomolecules in solution, we investigate the geometries and energetics of two, three and four binding sites cooperatively binding one copper ion. These geometries are then used as inputs for classical molecular dynamics simulations. We find that copper binding affects the secondary structure of the PrP and that it stabilizes the unstructured (unfolded) part of the protein.

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

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

Molecular dynamics simulations of apocupredoxins: insights into the formation and stabilization of copper sites under entatic control.

PubMed

Abriata, Luciano A; Vila, Alejandro J; Dal Peraro, Matteo

2014-06-01

Cupredoxins perform copper-mediated long-range electron transfer (ET) in biological systems. Their copper-binding sites have evolved to force copper ions into ET-competent systems with decreased reorganization energy, increased reduction potential, and a distinct electronic structure compared with those of non-ET-competent copper complexes. The entatic or rack-induced state hypothesis explains these special properties in terms of the strain that the protein matrix exerts on the metal ions. This idea is supported by X-ray structures of apocupredoxins displaying "closed" arrangements of the copper ligands like those observed in the holoproteins; however, it implies completely buried copper-binding atoms, conflicting with the notion that they must be exposed for copper loading. On the other hand, a recent work based on NMR showed that the copper-binding regions of apocupredoxins are flexible in solution. We have explored five cupredoxins in their "closed" apo forms through molecular dynamics simulations. We observed that prearranged ligand conformations are not stable as the X-ray data suggest, although they do form part of the dynamic landscape of the apoproteins. This translates into variable flexibility of the copper-binding regions within a rigid fold, accompanied by fluctuations of the hydrogen bonds around the copper ligands. Major conformations with solvent-exposed copper-binding atoms could allow initial binding of the copper ions. An eventual subsequent incursion to the closed state would result in binding of the remaining ligands, trapping the closed conformation thanks to the additional binding energy and the fastening of noncovalent interactions that make up the rack.

Strontium and cesium release mechanisms during unsaturated flow through waste-weathered Hanford sediments.

PubMed

Chang, Hyun-Shik; Um, Wooyong; Rod, Kenton; Serne, R Jeff; Thompson, Aaron; Perdrial, Nicolas; Steefel, Carl I; Chorover, Jon

2011-10-01

Leaching behavior of Sr and Cs in the vadose zone of Hanford site (Washington) was studied with laboratory-weathered sediments mimicking realistic conditions beneath the leaking radioactive waste storage tanks. Unsaturated column leaching experiments were conducted using background Hanford pore water focused on first 200 pore volumes. The weathered sediments were prepared by 6 months reaction with a synthetic Hanford tank waste leachate containing Sr and Cs (10(-5) and 10(-3) molal representative of LO- and HI-sediment, respectively) as surrogates for (90)Sr and (137)Cs. The mineral composition of the weathered sediments showed that zeolite (chabazite-type) and feldspathoid (sodalite-type) were the major byproducts but different contents depending on the weathering conditions. Reactive transport modeling indicated that Cs leaching was controlled by ion-exchange, while Sr release was affected primarily by dissolution of the secondary minerals. The later release of K, Al, and Si from the HI-column indicated the additional dissolution of a more crystalline mineral (cancrinite-type). A two-site ion-exchange model successfully simulated the Cs release from the LO-column. However, a three-site ion-exchange model was needed for the HI-column. The study implied that the weathering conditions greatly impact the speciation of the secondary minerals and leaching behavior of sequestrated Sr and Cs.

Tunable reaction potentials in open framework nanoparticle battery electrodes for grid-scale energy storage.

PubMed

Wessells, Colin D; McDowell, Matthew T; Peddada, Sandeep V; Pasta, Mauro; Huggins, Robert A; Cui, Yi

2012-02-28

The electrical energy grid has a growing need for energy storage to address short-term transients, frequency regulation, and load leveling. Though electrochemical energy storage devices such as batteries offer an attractive solution, current commercial battery technology cannot provide adequate power, and cycle life, and energy efficiency at a sufficiently low cost. Copper hexacyanoferrate and nickel hexacyanoferrate, two open framework materials with the Prussian Blue structure, were recently shown to offer ultralong cycle life and high-rate performance when operated as battery electrodes in safe, inexpensive aqueous sodium ion and potassium ion electrolytes. In this report, we demonstrate that the reaction potential of copper-nickel alloy hexacyanoferrate nanoparticles may be tuned by controlling the ratio of copper to nickel in these materials. X-ray diffraction, TEM energy dispersive X-ray spectroscopy, and galvanostatic electrochemical cycling of copper-nickel hexacyanoferrate reveal that copper and nickel form a fully miscible solution at particular sites in the framework without perturbing the structure. This allows copper-nickel hexacyanoferrate to reversibly intercalate sodium and potassium ions for over 2000 cycles with capacity retentions of 100% and 91%, respectively. The ability to precisely tune the reaction potential of copper-nickel hexacyanoferrate without sacrificing cycle life will allow the development of full cells that utilize the entire electrochemical stability window of aqueous sodium and potassium ion electrolytes.

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...

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 copper on the properties of Pr-Dy-Fe-Co-B sintered magnets

NASA Astrophysics Data System (ADS)

Kablov, E. N.; Piskorskii, V. P.; Valeev, R. A.; Volkov, N. V.; Davydova, E. A.; Shaikhutdinov, K. A.; Balaev, D. A.; Semenov, S. V.

2014-01-01

The effect of copper on the properties of magnets (Pr0.52Dy0.48)13(Fe65Co0.35)80.3 - x Cu x B6.7 ( x = 0-10) has been studied. Alloying with copper is shown to decrease the sintering temperature and to increase the content of the principal (Pr,Dy)2(Fe,Co)14B magnetic phase. For compositions with x = 1.3-3.3, copper is found to affect the value and sign of the temperature induction coefficient (TIC). It is shown that the effect of copper on the TIC is determined by the substitution of copper ions for iron ions in lattice sites, which are coupled via an antiferromagnetic exchange interaction.

Isolating metal-tolerant bacteria capable of removing copper, chromium, and arsenic from treated wood

Treesearch

Carol A. Clausen

2000-01-01

Bioremediation of chromated copper arsenate-treated waste wood with one or more metal-tolerant bacteria is a potential method of naturally releasing metals from treated wood fibre. Sampling eight environments with elevated levels of copper, chromium, and arsenic resulted in the isolation of 28 bacteria with the capability of releasing one or more of the components from...

Comparison of galvanic corrosion potential of metal injection molded brackets to that of conventional metal brackets with nickel-titanium and copper nickel-titanium archwire combinations.

PubMed

Varma, D Praveen Kumar; Chidambaram, S; Reddy, K Baburam; Vijay, M; Ravindranath, D; Prasad, M Rajendra

2013-05-01

The aim of the study is to investigate the galvanic corrosion potential of metal injection molding (MIM) brackets to that of conventional brackets under similar in vitro conditions with nickel-titanium and copper nickel-titanium archwires. Twenty-five maxillary premolar MIM stainless steel brackets and 25 conventional stainless steel brackets and archwires, 0.16 inch, each 10 mm length, 25 nickeltitanium wires, 25 copper nickel-titanium wires were used. They were divided into four groups which had five samples each. Combination of MIM bracket with copper nickel-titanium wire, MIM bracket with nickel-titanium wire and conventional stainless steel brackets with copper nickel-titanium wire and conventional stainless steel brackets with nickel-titanium wires which later were suspended in 350 ml of 1 M lactic acid solution media. Galvanic corrosion potential of four groups were analyzed under similar in vitro conditions. Precorrosion and postcorrosion elemental composition of MIM and conventional stainless steel bracket by scanning electron microscope (SEM) with energy dispersive spectroscope (EDS) was done. MIM bracket showed decreased corrosion susceptibility than conventional bracket with copper nickeltitanium wire. Both MIM and conventional bracket showed similar corrosion resistance potential in association with nickel-titanium archwires. It seems that both brackets are more compatible with copper nickel-titanium archwires regarding the decrease in the consequences of galvanic reaction. The EDS analysis showed that the MIM brackets with copper nickel-titanium wires released less metal ions than conventional bracket with copper nickeltitanium wires. MIM brackets showed decreased corrosion susceptibility, copper nickel-titanium archwires are compatible with both the brackets than nickel-titanium archwires. Clinically MIM and conventional brackets behaved more or less similarly in terms of corrosion resistance. In order to decrease the corrosion potential of MIM brackets, more precise manufacturing technique should be improved to get a more smoother surface finish.

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.

H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Lim, Sung Nam; Song, Shin Ae; Jeong, Yong-Cheol; Kang, Hyun Woo; Park, Seung Bin; Kim, Ki Young

2017-10-01

Perovskite-type photocatalysts of CaCu x Ti1- x O3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g-1 h-1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g-1 h-1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

Synthesis, structure, spectroscopic and electrochemical properties of (2-amino-4-methylpyrimidine)-(pyridine-2,6-dicarboxylato)copper(II) monohydrate

NASA Astrophysics Data System (ADS)

Uçar, İbrahim; Karabulut, Bünyamin; Bulut, Ahmet; Büyükgüngör, Orhan

2007-05-01

The (2-amino-4-methylpyrimidine)-(pyridine-2,6-dicarboxylato)copper(II) monohydrate complex was synthesized and characterized by spectroscopic (IR, UV/Vis, EPR), thermal (TG/DTA) and electrochemical methods. X-ray structural analysis of the title complex revealed that the copper ion can be considered to have two coordination spheres. In the first coordination sphere the copper ion forms distorted square-planar geometry with trans-N 2O 2 donor set, and also the metal ion is weakly bonded to the amino-nitrogen in the layer over and to the carboxylic oxygen in the layer underneath in the second coordination sphere. The second coordination environment on the copper ion is attributed to pseudo octahedron. The powder EPR spectra of Cu(II) complex at room and liquid nitrogen temperature were recorded. The calculated g and A parameters have indicated that the paramagnetic centre is axially symmetric. The molecular orbital bond coefficients of the Cu(II) ion in d 9 state is also calculated by using EPR and optical absorption parameters. The cyclic voltammogram of the title complex investigated in DMSO (dimethylsulfoxide) solution exhibits only metal centered electroactivity in the potential range -1.25 to 1.5 V versus Ag/AgCl reference electrode.

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.

Modeling of batch sorber system: kinetic, mechanistic, and thermodynamic modeling

NASA Astrophysics Data System (ADS)

Mishra, Vishal

2017-10-01

The present investigation has dealt with the biosorption of copper and zinc ions on the surface of egg-shell particles in the liquid phase. Various rate models were evaluated to elucidate the kinetics of copper and zinc biosorptions, and the results indicated that the pseudo-second-order model was more appropriate than the pseudo-first-order model. The curve of the initial sorption rate versus the initial concentration of copper and zinc ions also complemented the results of the pseudo-second-order model. Models used for the mechanistic modeling were the intra-particle model of pore diffusion and Bangham's model of film diffusion. The results of the mechanistic modeling together with the values of pore and film diffusivities indicated that the preferential mode of the biosorption of copper and zinc ions on the surface of egg-shell particles in the liquid phase was film diffusion. The results of the intra-particle model showed that the biosorption of the copper and zinc ions was not dominated by the pore diffusion, which was due to macro-pores with open-void spaces present on the surface of egg-shell particles. The thermodynamic modeling reproduced the fact that the sorption of copper and zinc was spontaneous, exothermic with the increased order of the randomness at the solid-liquid interface.

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

Computational study of a calcium release-activated calcium channel

NASA Astrophysics Data System (ADS)

Talukdar, Keka; Shantappa, Anil

2016-05-01

The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

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.

Solid-phase materials for chelating metal ions and methods of making and using same

DOEpatents

Harrup, Mason K.; Wey, John E.; Peterson, Eric S.

2003-06-10

A solid material for recovering metal ions from aqueous streams, and methods of making and using the solid material, are disclosed. The solid material is made by covalently bonding a chelating agent to a silica-based solid, or in-situ condensing ceramic precursors along with the chelating agent to accomplish the covalent bonding. The chelating agent preferably comprises a oxime type chelating head, preferably a salicylaldoxime-type molecule, with an organic tail covalently bonded to the head. The hydrocarbon tail includes a carbon-carbon double bond, which is instrumental in the step of covalently bonding the tail to the silica-based solid or the in-situ condensation. The invented solid material may be contacted directly with aqueous streams containing metal ions, and is selective to ions such as copper (II) even in the presence of such ions as iron (III) and other materials that are present in earthen materials. The solid material with high selectivity to copper may be used to recover copper from mining and plating industry streams, to replace the costly and toxic solvent extraction steps of conventional copper processing.

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.

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

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

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.

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

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.

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.

Recovery of copper and cyanide from waste cyanide solutions using emulsion liquid membrane with LIX 7950 as the carrier.

PubMed

Xie, Feng; Wang, Wei

2017-08-01

The feasibility of using emulsion liquid membranes (ELMs) with the guanidine extractant LIX 7950 as the mobile carrier for detoxifying copper-containing waste cyanide solutions has been determined. Relatively stable ELMs can be maintained under suitable stirring speed during mixing ELMs and the external solution. Effective extraction of copper cyanides by ELMs only occurs at pH below 11. High copper concentration in the external phase and high volume ratio of the external phase to ELMs result in high transport rates of copper and cyanide. High molar ratio of cyanide to copper tends to suppress copper extraction. The presence of thiocyanate ion significantly depresses the transport of copper and cyanide through the membrane while the thiosulfate ion produces less impact on copper removal by ELMs. Zinc and nickel cyanides can also be effectively extracted by ELMs. More than 90% copper and cyanide can be effectively removed from alkaline cyanide solutions by ELMs under suitable experimental conditions, indicating the effectiveness of using the designed ELM for recovering copper and cyanide from waste cyanide solutions.

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.

DJ-1 Is a Copper Chaperone Acting on SOD1 Activation*

PubMed Central

Girotto, Stefania; Cendron, Laura; Bisaglia, Marco; Tessari, Isabella; Mammi, Stefano; Zanotti, Giuseppe; Bubacco, Luigi

2014-01-01

Lack of oxidative stress control is a common and often prime feature observed in many neurodegenerative diseases. Both DJ-1 and SOD1, proteins involved in familial Parkinson disease and amyotrophic lateral sclerosis, respectively, play a protective role against oxidative stress. Impaired activity and modified expression of both proteins have been observed in different neurodegenerative diseases. A potential cooperative action of DJ-1 and SOD1 in the same oxidative stress response pathway may be suggested based on a copper-mediated interaction between the two proteins reported here. To investigate the mechanisms underlying the antioxidative function of DJ-1 in relation to SOD1 activity, we investigated the ability of DJ-1 to bind copper ions. We structurally characterized a novel copper binding site involving Cys-106, and we investigated, using different techniques, the kinetics of DJ-1 binding to copper ions. The copper transfer between the two proteins was also examined using both fluorescence spectroscopy and specific biochemical assays for SOD1 activity. The structural and functional analysis of the novel DJ-1 copper binding site led us to identify a putative role for DJ-1 as a copper chaperone. Alteration of the coordination geometry of the copper ion in DJ-1 may be correlated to the physiological role of the protein, to a potential failure in metal transfer to SOD1, and to successive implications in neurodegenerative etiopathogenesis. PMID:24567322

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

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.

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.

Newly identified interfibrillar collagen crosslinking suppresses cell proliferation and remodelling.

PubMed

Marelli, Benedetto; Le Nihouannen, Damien; Hacking, S Adam; Tran, Simon; Li, Jingjing; Murshed, Monzur; Doillon, Charles J; Ghezzi, Chiara E; Zhang, Yu Ling; Nazhat, Showan N; Barralet, Jake E

2015-06-01

Copper is becoming recognised as a key cation in a variety of biological processes. Copper chelation has been studied as a potential anti-angiogenic strategy for arresting tumour growth. Conversely the delivery of copper ions and complexes in vivo can elicit a pro-angiogenic effect. Previously we unexpectedly found that copper-stimulated intraperitoneal angiogenesis was accompanied by collagen deposition. Here, in hard tissue, not only was healing accelerated by copper, but again enhanced deposition of collagen was detected at 2 weeks. Experiments with reconstituted collagen showed that addition of copper ions post-fibrillogenesis rendered plastically-compressed gels resistant to collagenases, enhanced their mechanical properties and increased the denaturation temperature of the protein. Unexpectedly, this apparently interfibrillar crosslinking was not affected by addition of glucose or ascorbic acid, which are required for crosslinking by advanced glycation end products (AGEs). Fibroblasts cultured on copper-crosslinked gels did not proliferate, whereas those cultured with an equivalent quantity of copper on either tissue culture plastic or collagen showed no effect compared with controls. Although non-proliferative, fibroblasts grown on copper-cross-linked collagen could migrate, remained metabolically active for at least 14 days and displayed a 6-fold increase in Mmps 1 and 3 mRNA expression compared with copper-free controls. The ability of copper ions to crosslink collagen fibrils during densification and independently of AGEs or Fenton type reactions is previously unreported. The effect on MMP susceptibility of collagen and the dramatic change in cell behaviour on this crosslinked ECM may contribute to shedding some light on unexplained phenomena as the apparent benefit of copper complexation in fibrotic disorders or the enhanced collagen deposition in response to localised copper delivery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Cu(II)-reconstituted ACC Oxidase using experimental and theoretical approaches.

PubMed

El Bakkali-Tahéri, Nadia; Tachon, Sybille; Orio, Maylis; Bertaina, Sylvain; Martinho, Marlène; Robert, Viviane; Réglier, Marius; Tron, Thierry; Dorlet, Pierre; Simaan, A Jalila

2017-06-01

1-Aminocyclopropane-1-carboxylic acid oxidase (ACCO) is a non heme iron(II) containing enzyme that catalyzes the final step of the ethylene biosynthesis in plants. The iron(II) ion is bound in a facial triad composed of two histidines and one aspartate (H177, D179 and H234). Several active site variants were generated to provide alternate binding motifs and the enzymes were reconstituted with copper(II). Continuous wave (cw) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopies as well as Density Functional Theory (DFT) calculations were performed and models for the copper(II) binding sites were deduced. In all investigated enzymes, the copper ion is equatorially coordinated by the two histidine residues (H177 and H234) and probably two water molecules. The copper-containing enzymes are inactive, even when hydrogen peroxide is used in peroxide shunt approach. EPR experiments and DFT calculations were undertaken to investigate substrate's (ACC) binding on the copper ion and the results were used to rationalize the lack of copper-mediated activity. Copyright © 2017 Elsevier Inc. All rights reserved.

Rapid determination of trace copper in animal feed based on micro-plate colorimetric reaction and statistical partitioning correction.

PubMed

Niu, Yiming; Wang, Jiayi; Zhang, Chi; Chen, Yiqiang

2017-04-15

The objective of this study was to develop a micro-plate based colorimetric assay for rapid and high-throughput detection of copper in animal feed. Copper ion in animal feed was extracted by trichloroacetic acid solution and reduced to cuprous ion by hydroxylamine. The cuprous ion can chelate with 2,2'-bicinchoninic acid to form a Cu-BCA complex which was detected with high sensitivity by micro-plate reader at 354nm. The whole assay procedure can be completed within 20min. To eliminate matrix interference, a statistical partitioning correction approach was proposed, which makes the detection of copper in complex samples possible. The limit of detection was 0.035μg/mL and the detection range was 0.1-10μg/mL of copper in buffer solution. Actual sample analysis indicated that this colorimetric assay produced results consistent with atomic absorption spectrometry analysis. These results demonstrated that the developed assay can be used for rapid determination of copper in animal feed. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Effect of weathering on chromated copper arsenate (CCA) treated wood : leaching of metal salts and change in water repellency

Treesearch

R. Sam Williams; Stan Lebow; Patricia Lebow

2003-01-01

Wood pressure-treated with chromated copper arsenate (CCA) wood preservative is commonly used for outdoor construction. Oxides of arsenic, copper, and chromium are bound in the wood by a complex series of chemical reactions, but a small percentage of these compounds are gradually released by leaching and weathering. Recent studies suggest that the release of these...

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.?

The structural flexibility of the human copper chaperone Atox1: Insights from combined pulsed EPR studies and computations.

PubMed

Levy, Ariel R; Turgeman, Meital; Gevorkyan-Aiapetov, Lada; Ruthstein, Sharon

2017-08-01

Metallochaperones are responsible for shuttling metal ions to target proteins. Thus, a metallochaperone's structure must be sufficiently flexible both to hold onto its ion while traversing the cytoplasm and to transfer the ion to or from a partner protein. Here, we sought to shed light on the structure of Atox1, a metallochaperone involved in the human copper regulation system. Atox1 shuttles copper ions from the main copper transporter, Ctr1, to the ATP7b transporter in the Golgi apparatus. Conventional biophysical tools such as X-ray or NMR cannot always target the various conformational states of metallochaperones, owing to a requirement for crystallography or low sensitivity and resolution. Electron paramagnetic resonance (EPR) spectroscopy has recently emerged as a powerful tool for resolving biological reactions and mechanisms in solution. When coupled with computational methods, EPR with site-directed spin labeling and nanoscale distance measurements can provide structural information on a protein or protein complex in solution. We use these methods to show that Atox1 can accommodate at least four different conformations in the apo state (unbound to copper), and two different conformations in the holo state (bound to copper). We also demonstrate that the structure of Atox1 in the holo form is more compact than in the apo form. Our data provide insight regarding the structural mechanisms through which Atox1 can fulfill its dual role of copper binding and transfer. © 2017 The Protein Society.

Is a high serum copper concentration a risk factor for implantation failure?

PubMed

Matsubayashi, Hidehiko; Kitaya, Kotaro; Yamaguchi, Kohei; Nishiyama, Rie; Takaya, Yukiko; Ishikawa, Tomomoto

2017-08-10

Copper-containing contraceptive devices may deposit copper ions in the endometrium, resulting in implantation failure. The deposition of copper ions in many organs has been reported in patients with untreated Wilson's disease. Since these patients sometimes exhibit subfertility and/or early pregnancy loss, copper ions were also considered to accumulate in the uterine endometrium. Wilson's disease patients treated with zinc successfully delivered babies because zinc interfered with the absorption of copper from the gastrointestinal tract. These findings led to the hypothesis that infertile patients with high serum copper concentrations may have implantation failure due to the excess accumulation of copper ions. The relationship between implantation (pregnancy) rates and serum copper concentrations has not yet been examined. The Japanese government recently stated that actual copper intake was higher among Japanese than needed. Therefore, the aim of the present study was to investigate whether serum copper concentrations are related to the implantation (pregnancy) rates of human embryos in vivo. We included 269 patients (age <40 years old) who underwent vitrifying and warming single embryo transfer with a hormone replacement cycle using good blastocysts (3BB or more with Gardner's classification). Serum hCG, copper, and zinc concentrations were measured 16 days after the first date of progesterone replacement. We compared 96 women who were pregnant without miscarriage at 10 weeks of gestation (group P) and 173 women who were not pregnant (group NP). No significant differences were observed in age or BMI between the groups. Copper concentrations were significantly higher in group NP (average 193.2 μg/dL) than in group P (average 178.1 μg/dL). According to the area under the curve (AUC) on the receiver operating characteristic curve for the prediction of clinical pregnancy rates, the Cu/Zn ratio (AUC 0.64, 95% CI 0.54-0.71) was a better predictor than copper or zinc. When we set the cut-off as 1.59/1.60 for the Cu/Zn ratio, sensitivity, specificity, the positive predictive value, and negative predictive value were 0.98, 0.29, 0.71, and 0.88, respectively. Our single-center retrospective study suggests that high serum copper concentrations (high Cu/Zn ratio) are a risk factor for implantation failure.

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...

Investigation of simultaneous biosorption of copper(II) and chromium(VI) on dried Chlorella vulgaris from binary metal mixtures: Application of multicomponent adsorption isotherms

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

Aksu, Z.; Acikel, U.; Kutsal, T.

1999-02-01

Although the biosorption of single metal ions to various kinds of microorganisms has been extensively studied and the adsorption isotherms have been developed for only the single metal ion situation, very little attention has been given to the bioremoval and expression of adsorption isotherms of multimetal ions systems. In this study the simultaneous biosorption of copper(II) and chromium(VI) to Chlorella vulgaris from a binary metal mixture was studied and compared with the single metal ion situation in a batch stirred system. The effects of pH and single- and dual-metal ion concentrations on the equilibrium uptakes were investigated. In previous studiesmore » the optimum biosorption pH had been determined as 4.0 for copper(II) and as 2.0 for chromium(VI). Multimetal ion biosorption studies were performed at these two pH values. It was observed that the equilibrium uptakes of copper(II) or chromium(VI) ions were changed due to the biosorption pH and the presence of other metal ions. Adsorption isotherms were developed for both single- and dual-metal ions systems at these two pH values, and expressed by the mono- and multicomponent Langmuir and Freundlich adsorption models. Model parameters were estimated by nonlinear regression. It was seen that the adsorption equilibrium data fitted very well to the competitive Freundlich model in the concentration ranges studied.« less

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.

Measurements on the gas desorption yield of the oxygen-free copper irradiated with low-energy Xe10+ and O+

NASA Astrophysics Data System (ADS)

Dong, Z. Q.; Li, P.; Yang, J. C.; Yuan, Y. J.; Xie, W. J.; Zheng, W. H.; Liu, X. J.; Chang, J. J.; Luo, C.; Meng, J.; Wang, J. C.; Wang, Y. M.; Yin, Y.; Chai, Z.

2017-10-01

Heavy ion beam lost on the accelerator vacuum wall will release quantity of gas molecules and make the vacuum system deteriorate seriously. This phenomenon is called dynamic vacuum effect, observed at CERN, GSI and BNL, leading to the decrease of beam lifetime when increasing beam intensity. Heavy ion-induced gas desorption, which results in dynamic vacuum effect, becomes one of the most important problems for future accelerators proposed to operate with intermediate charge state beams. In order to investigate the mechanism of this effect and find the solution method for the IMP future project High Intensity heavy-ion Accelerator Facility (HIAF), which is designed to extract 1 × 1011 uranium particles with intermediate charge state per cycle, two dedicated experiment setups have been installed at the beam line of the CSR and the 320 kV HV platform respectively. Recently, experiment was performed at the 320 kV HV platform to study effective gas desorption with oxygen-free copper target irradiated with continuous Xe10+ beam and O+ beam in low energy regime. Gas desorption yield in this energy regime was calculated and the link between gas desorption and electronic energy loss in Cu target was proved. These results will be used to support simulations about dynamic vacuum effect and optimizations about efficiency of collimators to be installed in the HIAF main synchrotron BRing, and will also provide guidance for future gas desorption measurements in high energy regime.

Microbial biofilms for the removal of Cu²⁺ from CMP wastewater.

PubMed

Mosier, Aaron P; Behnke, Jason; Jin, Eileen T; Cady, Nathaniel C

2015-09-01

The modern semiconductor industry relies heavily on a process known as chemical mechanical planarization, which uses physical and chemical processes to remove excess material from the surface of silicon wafers during microchip fabrication. This process results in large volumes of wastewater containing dissolved metals including copper (Cu(2+)), which must then be filtered and treated before release into municipal waste systems. We have investigated the potential use of bacterial and fungal biomass as an alternative to the currently used ion-exchange resins for the adsorption of dissolved Cu(2+) from high-throughput industrial waste streams. A library of candidate microorganisms, including Lactobacillus casei and Pichia pastoris, was screened for ability to bind Cu(2+) from solution and to form static biofilm communities within packed-bed adsorption columns. The binding efficiency of these biomass-based adsorption columns was assessed under various flow conditions and compared to that of industrially used ion-exchange resins. We demonstrated the potential to regenerate the biomass within the adsorption columns through the use of a hydrochloric acid wash, and subsequently reuse the columns for additional copper binding. While the binding efficiency and capacity of the developed L. casei/P. pastoris biomass filters was inferior to ion-exchange resin, the potential for repeated reuse of these filters, coupled with the advantages of a more sustainable "green" adsorption process, make this technique an attractive candidate for use in industrial-scale CMP wastewater treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

An investigation on the electrochemical behavior of the Co/Cu multilayer system.

PubMed

Mahshid, S S; Dolati, A

2010-09-01

Co/Cu multilayers were deposited in a sulfate solution by controlling the current and potential for the deposition of cobalt and copper layer respectively. The electrochemical behavior of these multilayers was studied by cyclic voltammetry and current transients. In addition, a mathematical analysis was used to characterize the electrodeposition system. Simultaneously, the nucleation and growth mechanisms were monitored by these techniques. In this case, the results clearly showed that electrodeposition of cobalt layers was a kinetically controlled process while the reduction of copper ions was a diffusion-control process. Although nucleation mechanism of the single Co deposit was found as a progressive system, it was found as an instantaneous system with three-dimensional growth mechanism in the Co/Cu bilayer deposition. Atomic Forced Microscopy images of the Co/Cu multilayer also confirmed the aforementioned nucleation mechanism, where it was expected that the growth of multilayer films would form a laminar-type structure containing a large number of equally-sized rounded grains in each layer.

Removal of copper from aqueous solution using perlite

NASA Astrophysics Data System (ADS)

Tanaydin, Mehmet Kayra; Tanaydin, Zümra Bakici; Ince, Muharrem; Demırkiran, Nizamettin

2017-04-01

The wastewaters containing organic and inorganic pollutants after many industrial processes such as metal plating, mining, textile, alloy, battery and industrial chemicals, are often discharged to environment. Heavy metals among these pollutants have highly stable, toxic, non-degradable and carcinogenic characters. They affect not only ecological system, but also human health and many life forms. Therefore, these contaminants should be eliminated or reduced to allowable levels before releasing to environment. Most of heavy metals have toxic character even at low concentrations of about 0.1-0.3 ppm. Treatment technologies such as filtration, ion exchange, precipitation, electrodeposition, reverse osmosis, sedimentation, and adsorption have been applied for removal of heavy metals from aqueous solutions. Adsorption is one of the most common and widely applied methods to eliminate the metal ions from waste solutions because of its simplicity and cost effectiveness. Activated carbon, clay minerals, ion exchange resins and various agricultural residues can be used as adsorbent materials in this process [1-3].

Subneurotoxic copper(II)-induced NF-κB-dependent microglial activation is associated with mitochondrial ROS

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

Hu, Zhuqin; Yu, Fengxiang; Gong, Ping

2014-04-15

Microglia-mediated neuroinflammation and the associated neuronal damage play critical roles in the pathogenesis of neurodegenerative disorders. Evidence shows an elevated concentration of extracellular copper(II) in the brains of these disorders, which may contribute to neuronal death through direct neurotoxicity. Here we explored whether extracellular copper(II) triggers microglial activation. Primary rat microglia and murine microglial cell line BV-2 cells were cultured and treated with copper(II). The content of tumor necrosis factor-α (TNF-α) and nitric oxide in the medium was determined. Extracellular hydrogen peroxide was quantified by a fluorometric assay with Amplex Red. Mitochondrial superoxide was measured by MitoSOX oxidation. At subneurotoxicmore » concentrations, copper(II) treatment induced a dose- and time-dependent release of TNF-α and nitric oxide from microglial cells, and caused an indirect, microglia-mediated neurotoxicity that was blocked by inhibition of TNF-α and nitric oxide production. Copper(II)-initiated microglial activation was accompanied with reduced IkB-α expression as well as phosphorylation and translocation of nuclear factor-κB (NF-κB) p65 and was blocked by NF-κB inhibitors (BAY11-7082 and SC-514). Moreover, copper(II) treatment evoked a rapid release of hydrogen peroxide from microglial cells, an effect that was not affected by NADPH oxidase inhibitors. N-acetyl-cysteine, a scavenger of reactive oxygen species (ROS), abrogated copper(II)-elicited microglial release of TNF-α and nitric oxide and subsequent neurotoxicity. Importantly, mitochondrial production of superoxide, paralleled to extracellular release of hydrogen peroxide, was induced after copper(II) stimulation. Our findings suggest that extracellular copper(II) at subneurotoxic concentrations could trigger NF-κB-dependent microglial activation and subsequent neurotoxicity. NADPH oxidase-independent, mitochondria-derived ROS may be involved in this activation. - Highlights: • Subneurotoxic copper(II) triggers NF-κB-dependent microglial activation. • This activation leads to hippocampal neuronal death. • This activation may involve mitochondria-derived reactive oxygen species.« less

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

Assessment of the bioaccessibility of micronized copper wood in synthetic stomach fluid

EPA Science Inventory

The widespread use of copper in treated lumber may result in a potential for human exposure. Due to a lack of information concerning the release of copper from treated wood particles following oral ingestion, the in vitro bioaccessibility of copper from copper-treated wood dust i...

Strontium and cesium release mechanisms during unsaturated flow through waste-weathered Hanford sediments

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

Chang, Hyun-Shik; Um, Wooyong; Rod, Kenton A.

2011-10-01

Leaching behavior of Sr and Cs in the vadose zone of Hanford site (WA, USA) was studied with laboratory-weathered sediments mimicking realistic conditions beneath the leaking radioactive waste storage tanks. Unsaturated column leaching experiments were conducted using background Hanford pore water focused on first 200 pore volumes. The weathered sediments were prepared by 6 months reaction with a synthetic Hanford tank waste leachate containing Sr and Cs (10-5 and 10-3 molal representative of LO- and HI-sediment, respectively) as surrogates for 90Sr and 137Cs. The mineral composition of the weathered sediments showed that zeolite (chabazite-type) and feldspathoid (sodalite-type) were the majormore » byproducts but different contents depending on the weathering conditions. Reactive transport modeling indicated that Cs leaching was controlled by ion-exchange, while Sr release was affected primarily by dissolution of the secondary minerals. The later release of K, Al, and Si from the HI-column indicated the additional dissolution of a more crystalline mineral (cancrinite-type). A two-site ion-exchange model successfully simulated the Cs release from the LO-column. However, a three-site ion-exchange model was needed for the HI-column. The study implied that the weathering conditions greatly impact the speciation of the secondary minerals and leaching behavior of sequestrated Sr and Cs.« less

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

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.

Homogenous and heterogenous advanced oxidation of two commercial reactive dyes.

PubMed

Balcioglu, I A; Arslan, I; Sacan, M T

2001-07-01

Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

Evaluation of Fe-containing Li2CuO2 on CO2 capture performed at different physicochemical conditions.

PubMed

Yañez-Aulestia, Ana; Ovalle-Encinia, Oscar; Pfeiffer, Heriberto

2018-06-05

Li 2 CuO 2 and different iron-containing Li 2 CuO 2 samples were synthesized by solid state reaction. On iron-containing samples, atomic sites of copper are substituted by iron ions in the lattice (XRD and Rietveld analyses). Iron addition induces copper release from Li 2 CuO 2 , which produce cationic vacancies and CuO, due to copper (Cu 2+ ) and iron (Fe 3+ ) valence differences. Two different physicochemical conditions were used for analyzing CO 2 capture on these samples; (i) high temperature and (ii) low temperature in presence of water vapor. At high temperatures, iron addition increased CO 2 chemisorption, due to structural and chemical variations on Li 2 CuO 2 . Kinetic analysis performed by first order reaction and Eyring models evidenced that iron addition on Li 2 CuO 2 induced a faster CO 2 chemisorption but a higher thermal dependence. Conversely, CO 2 chemisorption at low temperature in water vapor presence practically did not vary by iron addition, although hydration and hydroxylation processes were enhanced. Moreover, under these physicochemical conditions the whole sorption process became slower on iron-containing samples, due to metal oxides presence.

The CAMEO barium release - E/parallel/ fields over the polar cap

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Miller, M. L.; Pongratz, M. B.; Smith, G. M.; Smith, L. L.; Mende, S. B.; Nath, N. R.

1981-01-01

Four successive thermite barium releases at an altitude of 965 km over polar cap invariant latitudes 84 to 76 deg near magnetic midnight were conducted from the orbiting second stage of the vehicle that launched Nimbus 7; the releases were made as part of the CAMEO (Chemically Active Material Ejected in Orbit) program. This was the first opportunity to observe the behavior of conventional barium release when conducted at orbital velocity in the near-earth magnetic field. The principal unexpected characteristic in the release dynamics was the high, 1.4 to 2.6 km/s, initial Ba(+) expansion velocity relative to an expected velocity of 0.9 km/s. Attention is also given to neutral cloud expansion, initial ion cloud expansion, convective motion, and the characteristics of field-aligned motion. The possibility of measuring parallel electric fields over the polar cap by observing perturbations in the motion of the visible ions is assessed.

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.

Protective Effects of Lactobacillus plantarum CCFM8246 against Copper Toxicity in Mice

PubMed Central

Li, Xiaoxiao; Zhai, Qixiao; Wang, Gang; Zhang, Qiuxiang; Zhang, Hao; Chen, Wei

2015-01-01

Lactobacillus plantarum CCFM8246, which has a relatively strong copper binding capacity and tolerance to copper ions, was obtained by screening from 16 lactic acid bacteria in vitro. The selected strain was then applied to a mouse model to evaluate its protective function against copper intoxication in vivo. The experimental mice were divided into an intervention group and a therapy group; mice in the intervention group received co-administration of CCFM8246 and a copper ion solution by gavage, while mice in the therapy group were treated with CCFM8246 after 4 weeks of copper exposure. In both two groups, mice treated with copper alone and that treated with neither CCFM8246 nor copper served as positive and negative controls, respectively. At the end of the experimental period, the copper content in feces and tissues, the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum, and oxidation stress indices in liver and kidney tissue were determined. Learning and memory ability was evaluated by Morris water maze experiments. The results indicated that treatment with CCFM8246 significantly increased the copper content in feces to promote copper excretion, reduce the accumulation of copper in tissues, reverse oxidative stress induced by copper exposure, recover the ALT and AST in serum and improve the spatial memory of mice. PMID:26605944

Dynamics of a barium release in the magnetospheric tail

NASA Technical Reports Server (NTRS)

Mende, S. B.; Swenson, G. R.; Geller, S. P.; Doolittle, J. H.; Haerendel, G.

1989-01-01

The late time behavior of the May 13, 1985 magnetotail barium cloud is examined. The bulk dynamics of the cloud are studied based on triangulated data and data from Fabry-Perot Doppler velocity measurements. The changes in cloud morphology in relation to the in situ measurements made by the Ion Release Module satellite are discussed.

Electrochemical evidences and consequences of significant differences in ions diffusion rate in polyacrylate-based ion-selective membranes.

PubMed

Woźnica, Emilia; Mieczkowski, Józef; Michalska, Agata

2011-11-21

The origin and effect of surface accumulation of primary ions within the ion-selective poly(n-butyl acrylate)-based membrane, obtained by thermal polymerization, is discussed. Using a new method, based on the relation between the shape of a potentiometric plot and preconditioning time, the diffusion of copper ions in the membrane was found to be slow (the diffusion coefficient estimated to be close to 10(-11) cm(2) s(-1)), especially when compared to ion-exchanger counter ions--sodium cations diffusion (a diffusion coefficient above 10(-9) cm(2) s(-1)). The higher mobility of sodium ions than those of the copper-ionophore complex results in exposed ion-exchanger role leading to undesirably exposed sensitivity to sodium or potassium ions.

Role of copper/vanadium on the optoelectronic properties of reactive RF magnetron sputtered NiO thin films

NASA Astrophysics Data System (ADS)

Panneerselvam, Vengatesh; Chinnakutti, Karthik Kumar; Thankaraj Salammal, Shyju; Soman, Ajith Kumar; Parasuraman, Kuppusami; Vishwakarma, Vinita; Kanagasabai, Viswanathan

2018-04-01

In this study, pristine nickel oxide (NiO), copper-doped NiO (Cu-NiO) and vanadium-doped NiO (V-NiO) thin films were deposited using reactive RF magnetron co-sputtering as a function of dopant sputtering power. Cu (0-8 at%) and V (0-1 at%) were doped into the NiO lattice by varying the sputtering power of Cu and V in the range of 5-15 W. The effect of dopant concentration on optoelectronic behavior is investigated by UV-Vis-NIR spectrophotometer and Hall measurements. XRD analysis showed that the preferred orientation of the cubic phase for undoped NiO changes from (200) to (111) plane when the sputtering parameters are varied. The observed changes in the lattice parameters and bonding states of the doped NiO indicate the substitution of Ni ions by monovalent Cu and trivalent V ions. The optical bandgap of pristine NiO, Cu-NiO, and V-NiO was found to be 3.6, 3.45, and 3.05 eV, respectively, with decreased transmittance and resistivity. Further analysis using SEM and AFM described the morphological behavior of doped NiO thin films and Raman spectroscopy indicated the structural changes on doping. These findings would be helpful in fabricating solid-state solar cells using doped NiO as efficient hole transporting material.

Zinc and Copper Effects on Stability of Tubulin and Actin Networks in Dendrites and Spines of Hippocampal Neurons.

PubMed

Perrin, Laura; Roudeau, Stéphane; Carmona, Asuncion; Domart, Florelle; Petersen, Jennifer D; Bohic, Sylvain; Yang, Yang; Cloetens, Peter; Ortega, Richard

2017-07-19

Zinc and copper ions can modulate the activity of glutamate receptors. However, labile zinc and copper ions likely represent only the tip of the iceberg and other neuronal functions are suspected for these metals in their bound state. We performed synchrotron X-ray fluorescence imaging with 30 nm resolution to image total biometals in dendrites and spines from hippocampal neurons. We found that zinc is distributed all along the dendrites while copper is mainly pinpointed within the spines. In spines, zinc content is higher within the spine head while copper is higher within the spine neck. Such specific distributions suggested metal interactions with cytoskeleton proteins. Zinc supplementation induced the increase of β-tubulin content in dendrites. Copper supplementation impaired the β-tubulin and F-actin networks. Copper chelation resulted in the decrease of F-actin content in dendrites, drastically reducing the number of F-actin protrusions. These results indicate that zinc is involved in microtubule stability whereas copper is essential for actin-dependent stability of dendritic spines, although copper excess can impair the dendritic cytoskeleton.

C-H oxidation and chelation of a dipyrromethane mediated rapid colorimetric naked-eye Cu(ii) chemosensor.

PubMed

Rajmohan, Rajamani; Ayaz Ahmed, Khan Behlol; Sangeetha, Sampathkumar; Anbazhagan, Veerappan; Vairaprakash, Pothiappan

2017-09-08

Copper(ii) ion mediated C-H oxidation of dipyrromethanes (DPMs) to the corresponding dipyrrins followed by complexation invoked the selective sensing of copper(ii) ions in aqueous solutions. On the addition of copper, the colour of the DPM solution instantaneously changes from yellow to pink with the detection limit of 0.104 μM measured by absorption spectroscopy, whereas visible colour changes could be observed by the naked eye for concentrations as low as 3 μM.

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.

In vitro biocorrosion of Co-Cr-Mo implant alloy by macrophage cells.

PubMed

Lin, Hsin-Yi; Bumgardner, Joel D

2004-11-01

We hypothesized that macrophage cells and their released reactive chemical species (RCS) affect Co-Cr-Mo alloy's corrosion properties and that alloy corrosion products change macrophage cell behavior. A custom cell culture corrosion cell was used to evaluate how culture medium, cells, and RCS altered alloy corrosion in 3-day tests. Corrosion was evaluated by measuring total charge transfer at a constant potential using a potentiostat and metal ion release by atomic emission spectroscopy. Viability, proliferation, and NO (nitric oxide) and IL-1beta (interlukin-1beta) release were used to assess cellular response to alloy corrosion products. In the presence of activated cells, total charge transfers and Co ion release were the lowest (p < 0.05). This was attributed to an enhancement of the surface oxide by RCS. Cr and Mo release were not different between cells and activated cells. Low levels of metal ions did not affect cell viability, proliferation, or NO release, though IL-1beta released from the activated cells was higher on the alloy compared to the controls. These data support the hypothesis that macrophage cells and their RCS affect alloy corrosion. Changes in alloy corrosion by cells may be important to the development of host responses to the alloy and its corrosion products.

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 ...

Estimating Dermal Transfer of Copper Particles from the Surfaces of Pressure-Treated Lumber and Implications for Exposure

EPA Science Inventory

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 ba...

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.

Effect of simulated rainfall and weathering on release of preservative elements from CCA treated wood

Treesearch

Stan Lebow; R. Sam Williams; Patricia Lebow

2003-01-01

The release of arsenic from wood pressure-treated with chromated copper arsenate (CCA) can be decreased by application of wood finishes, but little is known about the types of finishes that are best suited for this purpose. This study evaluated the effects of finish water repellent content and ultraviolet (UV) radiation on the release of arsenic, copper, and chromium...

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.

Electrical conductivity of solutions of copper(II) nitrate crystalohydrate in dimethyl sulfoxide

NASA Astrophysics Data System (ADS)

Mamyrbekova, Aigul K.; Mamitova, A. D.; Mamyrbekova, Aizhan K.

2016-06-01

Conductometry is used to investigate the electric conductivity of Cu(NO3)2 ṡ 3H2O solutions in dimethyl sulfoxide in the 0.01-2.82 M range of concentrations and at temperatures of 288-318 K. The limiting molar conductivity of the electrolyte and the mobility of Cu2+ and NO 3 - ions, the effective coefficients of diffusion of copper(II) ions and nitrate ions, and the degree and constant of electrolytic dissociation are calculated for different temperatures from the experimental results. It is established that solutions containing 0.1-0.6 M copper nitrate trihydrate in DMSO having low viscosity and high electrical conductivity can be used in electrochemical deposition.

Explosively Driven Shock Induced Damage in OFHC Copper

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

Koller, D. D.; Hixson, R. S.; Gray, G. T. III

OFHC Cu samples were subjected to shock loading using plane wave HE lenses to produce a uniaxial Taylor wave profile (shock followed by immediate release). Upon arrival of the shock wave at the free surface of the sample, the wave is reflected and propagates back into the sample as a release wave. It is the interaction of initial and reflected release waves that place the material in a localized state of tension which can ultimately result in damage and possibly complete failure of the material. The peak tensile stress and its location in the material are determined by the wavemore » shape. Damage evolution processes and localized behavior are discussed based on results from time-resolved free surface velocity (VISAR) interferometry and post shock metallurgical analysis of the soft recovered samples.« less

Effect of copper and silver ionization on Legionella pneumophila eradication

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

Lin, Y.E.; Vidic, R.D.; Stout, J.E.

1995-11-01

The presence of Legionella pneumophila in water distribution systems has been epidemiologically linked to hospital-acquired Legionnaires` disease. The objective of this study was to evaluate the efficiency of copper and silver ions for inactivation of Legionella pneumophila. Experimental results showed that L. pneumophila was completely inactivated at copper concentration of 0.1 mg/L within the period of 2.5 hours while 6-log reduction requires a Ct value of 0.8 mg/L*hour. On the other hand, more than 24 hours was required to completely eradicate L. pneumophila at the highest silver ion concentration (0.08 mg/L) tested and only 4-log reduction is observed for Ctmore » value of 0.8 mg/L*hour. The effective synergism of these ions in eradicating L. pneumophila was observed for copper concentrations of 0.05 and silver concentration of 0.04 mg/L. One approach for the control of L. pneumophila in water distribution systems is to initiate copper/silver ion concentrations at 0.4/0.04 mg/L to achieve complete eradication of L. pneumophila already present in the water distribution system (as established in previous studies) followed by a lower residual (0.05/0.04 mg/L) protection against L. pneumophila in the incoming water.« less

Sorption of copper, zinc and cobalt by oat and oat products.

PubMed

Górecka, Danuta; Stachowiak, Jadwiga

2002-04-01

We determined copper, zinc and cobalt sorption by oat and its products under variable pH conditions as well as the content of neutral dietary fiber (NDF) and its fractional composition. Adsorbents in a model sorption system were: oat, dehulled oat, oats bran and oats flakes. Three various buffers (pH 1.8, 6.6 and 8.7) were used as dispersing solutions. Results collected during this study indicate that copper, zinc and cobalt sorption is significantly affected by the type of cereal raw material. Zinc and copper ions are subjected to higher sorption than cobalt ions. Examined metal ions were subjected to high sorption under conditions corresponding to the duodenum environment (pH 8.7), regardless of the kind of adsorbent. A little lower sorption capacity is observed under conditions close to the neutral environment, while the lowest one is found in environment reflecting conditions of stomach juice (pH 1.8). Zinc ions are bound intensively by dehulled oat, while oats flakes bound mostly copper and cobalt, independently on environmental conditions. Contents of dietary fiber in oat, dehulled oat, oat bran and oat flakes were: 40.1, 19.3, 20.3 and 14.3%, respectively. The dominating fraction in all oat products was the fraction of hemicelluloses. The content of remaining fractions varies in dependence on the product.

XAFS study of copper and silver nanoparticles in glazes of medieval middle-east lustreware (10th-13th century)

NASA Astrophysics Data System (ADS)

Padovani, S.; Puzzovio, D.; Sada, C.; Mazzoldi, P.; Borgia, I.; Sgamellotti, A.; Brunetti, B. G.; Cartechini, L.; D'Acapito, F.; Maurizio, C.; Shokoui, F.; Oliaiy, P.; Rahighi, J.; Lamehi-Rachti, M.; Pantos, E.

2006-06-01

It has recently been shown that lustre decoration of medieval and Renaissance pottery consists of silver and copper nanoparticles dispersed in the glassy matrix of the ceramic glaze. Here the findings of an X-ray absorption fine structure (XAFS) study on lustred glazes of shards belonging to 10th and 13rd century pottery from the National Museum of Iran are reported. Absorption spectra in the visible range have been also measured in order to investigate the relations between colour and glaze composition. Gold colour is mainly due to Ag nanoparticles, though Ag+, Cu+ and Cu2+ ions can be also dispersed within the glassy matrix, with different ratios. Red colour is mainly due to Cu nanoparticles, although some Ag nanoparticles, Ag+ and Cu+ ions can be present. The achievement of metallic Cu and the absence of Cu2+ indicate a higher reduction of copper in red lustre. These findings are in substantial agreement with previous results on Italian Renaissance pottery. In spite of the large heterogeneity of cases, the presence of copper and silver ions in the glaze confirms that lustre formation is mediated by a copper- and silver-alkali ion exchange, followed by nucleation and growth of metal nanoparticles.

Gold nanoparticle-sensitized quartz crystal microbalance sensor for rapid and highly selective determination of Cu(II) ions.

PubMed

Jin, Yulong; Huang, Yanyan; Liu, Guoquan; Zhao, Rui

2013-09-21

A novel quartz crystal microbalance (QCM) sensor for rapid, highly selective and sensitive detection of copper ions was developed. As a signal amplifier, gold nanoparticles (Au NPs) were self-assembled onto the surface of the sensor. A simple dip-and-dry method enabled the whole detection procedure to be accomplished within 20 min. High selectivity of the sensor towards copper ions is demonstrated by both individual and coexisting assays with interference ions. This gold nanoparticle mediated amplification allowed a detection limit down to 3.1 μM. Together with good repeatability and regeneration, the QCM sensor was also applied to the analysis of copper contamination in drinking water. This work provides a flexible method for fabricating QCM sensors for the analysis of important small molecules in environmental and biological samples.

Synthesis of zinc-crosslinked thiolated alginic acid beads and their in vitro evaluation as potential enteric delivery system with folic acid as model drug.

PubMed

Taha, M O; Aiedeh, K M; Al-Hiari, Y; Al-Khatib, H

2005-10-01

The aim of this study is to explore the potential of synthetic modifications of alginic acid as a method to enhance the stability of its complexes with divalent cations under physiological conditions. A fraction of algin's carboxylic acid moieties was substituted with thiol groups to different substitution degrees through conjugating alginate to cysteine to produce alginate-cysteine (AC) conjugates. Infrared spectrophotometry and iodometry were used to characterize the resulting polymeric conjugates in terms of structure and degree of substitution. Moreover, zinc ions were used to crosslink the resulting AC polymers. Folic acid loaded beads were prepared from Zinc-crosslinked AC polymers (AC-Zn) of different cysteine substitution degrees. The generated beads were then investigated in vitro for their capacity to modify folic acid release. AC-Zn polymeric beads resisted drug release under acidic conditions (pH 1.0). However, upon transfer to a phosphate buffer solution (pH 7.0) they released most of their contents almost immediately. This change in drug release behavior is most probably due to the sequestering of zinc cations by phosphate ions within the buffer solution to form insoluble chelates and, to a lesser extent, the ionization of the carboxylic acid and thiol moieties. Removal of zinc ions from the polymeric matrix seems to promote polymeric disintegration and subsequent drug release. A similar behavior is expected in vivo due to the presence of natural zinc sequestering agents in the intestinal fluids. AC-Zn polymers provided a novel approach for enteric drug delivery as drug release from these matrices complied with the USP specifications for enteric dosage forms.

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.

Concentration-dependent Cu(II) binding to prion protein

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Lu, Wenchang; Bernholc, Jerry

2008-03-01

The prion protein plays a causative role in several neurodegenerative diseases, including mad cow disease in cattle and Creutzfeldt-Jakob disease in humans. The normal function of the prion protein is unknown, but it has been linked to its ability to bind copper ions. Experimental evidence suggests that copper can be bound in three distinct modes depending on its concentration, but only one of those binding modes has been fully characterized experimentally. Using a newly developed hybrid DFT/DFT method [1], which combines Kohn-Sham DFT with orbital-free DFT, we have examined all the binding modes and obtained their detailed binding geometries and copper ion binding energies. Our results also provide explanation for experiments, which have found that when the copper concentration increases the copper binding mode changes, surprisingly, from a stronger to a weaker one. Overall, our results indicate that prion protein can function as a copper buffer. 1. Hodak, Lu, Bernholc, JCP, in press.

Investigating waste rock, tailings, slag and coal ash clinker as adsorbents for heavy metals: Batch and column studies

NASA Astrophysics Data System (ADS)

Letina, D.; Letshwenyo, W. M.

2018-06-01

Wastewater from the mining industry is a concern because most of the time it contains heavy metals with concentrations above permissible levels, posing a threat to terrestrial and aquatic life. The study was conducted to evaluate the effectiveness of locally available waste materials (waste rock, tailings, coal ash clinker, and slag) generated by BCL (Ltd) mine, a copper and nickel mining and smelting company in Botswana, for removal of nickel and copper from the real mining wastewater. Batch adsorption studies were conducted to establish the adsorptive efficiency and kinetics of each media with respect to nickel and copper ions. The best media was further evaluated through fixed bed column studies at 24 and 48 h empty bed contact time. The results indicate that the percentage removal for coal ash clinker, waste rock, smelter slag and tailings was 98%, 15%, 3% and -3% with respect to copper ions, and 46%, 9%, 7% and 2% with respect to nickel ions for each media respectively. Coal ash clinker followed pseudo first order kinetic model and Langmuir isotherm model with respect to nickel ions indicating the dominance of physisorption and mono layer coverage respectively. The Langmuir separation factor (RL) was 0.37 suggesting favourable adsorption onto the media. Fixed bed column studies revealed that copper was completely retained in the bed at both 24 and 48 h contact times. In the case of nickel, removal efficiency ranged between 83% and 99% when contact time was 48 h and between 68% and 99% when the contact time was reduced to 24 h. Breakthrough was not reached after 19 bed volumes. It can be concluded that coal ash clinker is a better candidate for the removal of copper and nickel ions from mining wastewater.

Medium dependent dual turn on/turn off fluorescence sensing for Cu2 + ions using AMI/SDS assemblies

NASA Astrophysics Data System (ADS)

Gujar, Varsha B.; Ottoor, Divya

2017-02-01

Behavior of Amiloride (AMI) as a metal ion sensor in anionic surfactant assemblies of varying concentrations at different pH is depicted in this work. From a non-sensor fluorophore, AMI has been transformed in to a tunable fluorosensor for Cu2 + ions in various SDS concentrations. At premicellar concentration of SDS, ion-pair complex is expected to be formed between AMI and SDS due to electrostatic interactions between them. However at CMC concentrations of SDS, fluorescence intensity of AMI is greatly enhanced with red shift in emission, due to the incorporation of AMI molecule in the hydrophobic micellar interface. The behavior of metal sensing by AMI-SDS assemblies gives rise to several interesting observations. Micellation of SDS has been greatly enhanced by increasing copper ion concentrations, as these counter ions screens the charge on monomers of SDS which lead to the aggregation at premicellar concentrations only. Concentrations and pH dependent discrete trends of interactions between SDS-AMI and SDS-Cu2 + ions, have given tunable fluorescence responses (fluorescence turn on/turn off) of AMI for added Cu2 + ions. The electrostatic interaction between the metal cations and the anionic surfactants is the driving force for bringing the metal ions near to the vicinity of micelle where AMI resides. Thus, a comprehensive understanding of the mechanism related to the 'turn on-turn off' fluorescence response of AMI with respect to pH and SDS concentration for effective Cu2 + ion sensing is illustrated in this work.

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.

Synthesis and characterization of novel ion-imprinted guanyl-modified cellulose for selective extraction of copper ions from geological and municipality sample.

PubMed

Kenawy, I M; Ismail, M A; Hafez, M A H; Hashem, M A

2018-04-21

The new ion-imprinted guanyl-modified cellulose (II.Gu-MC) was prepared for the separation and determination of Cu (II) ions in different real samples. Several techniques such as Fourier Transform Infrared (FT-IR), scanning electron microscope (SEM), thermal analysis, potentiograph and elemental analysis have been utilized for the characterization of II.Gu-MC. The adsorption behavior of the ion imprinted polymer (II.Gu-MC) was evaluated and compared to the non ion-imprinted polymer (NII.Gu-MC) at the optimum conditions. The selectivity and the adsorption capacity were greatly enhanced by using the ion-imprinted polymer, indicating its validation for the separation and determination of Cu 2+ ions in different matrices. The adsorption capacity by chelating fibers II.Gu-MC & NII.Gu-MC agreed with the second-order model, and the sorption-isotherm experiments revealed best agreement with Langmuir model. The adsorption capacity of II.Gu-MC and NII.Gu-MC were 115 and 55 mg·g -1 , respectively. The II.Gu-MC was successfully employed for the selective separation and determination of Cu(II) ions with high accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

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...

Development of Novel DNA Cleavage Systems Based on Copper Complexes. Synthesis and Characterisation of Cu(II) Complexes of Hydroxyflavones

PubMed Central

el Amrani, F. Ben-Allal; Perelló, L.; Torres, L.

2000-01-01

Copper(II) complexes of several hydroxyflavones were prepared and characterised through their physico-chemical properties. The nuclease activity of three synthesised complexes is reported. These copper(II) complexes present more nuclease activity than the ligands and the copper(II) ion. PMID:18475969

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.

Effect of chloride ion concentration on the galvanic corrosion of α phase brass by eccrine sweat.

PubMed

Meekins, Andrew; Bond, John W; Chaloner, Penelope

2012-07-01

Inductively coupled plasma mass spectrometry measurement of the relative concentration of sodium, chloride, calcium, and potassium ions in eccrine sweat deposits from 40 donors revealed positive correlations between chloride and sodium (ρ = 0.684, p < 0.01) and chloride and calcium ions (ρ = 0.91, p < 0.01). Correlations between ion concentration and the corrosion of α phase brass by the donated sweat were investigated by visual grading of the degree of corrosion, by measuring the copper/zinc ratio using energy-dispersive X-ray spectroscopy, and from a measurement of the potential difference between corroded and uncorroded brass when a large potential was applied to the uncorroded brass. An increasing copper/zinc ratio (indicative of dezincification) was found to correlate positively to both chloride ion concentration and visual grading of corrosion, while visual grading gave correlations with potential difference measurements that were indicative of the preferential surface oxidation of zinc rather than copper. © 2012 American Academy of Forensic Sciences.

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.

Colorimetric detection of copper in water using a Schiff base derivative

NASA Astrophysics Data System (ADS)

Peralta Domínguez, D.; Ramos-Ortiz, G.; Maldonado, J. L.; Rodriguez, M.; Meneses-Nava, M. A.; Barbosa-Garcia, O.; Santillan, R.; Farfán, N.

2013-09-01

Organic molecular sensors have the advantage of being used through an easy, fast, economical and reliable optical method for detecting toxic metal ions in our environment. In this work, we present a simple but highly specific organic ligand compound 5-Chloro-2-((E)-((E)-3-(4-(dimethylamino)phenyl)allylidene)amino)phenol (L1) that acts as a colorimetric sensor for ions in a mixture of acetonitrile/water (ratio 10:1, v:v). Binding interaction between L1 and various metal-ions has been established by ultraviolet-visible spectroscopic measurements that indicate favorable coordination of the ligand with selective metal ions, particularly, with copper. These results showed that the electronic transition band shape of L1 change after binding with copper in aqueous solution. L1 exhibited binding-induced color changes from yellow to pink one detected by the naked eye. This new sensor presented 2.5 × 10-6 M as limit detection, even under the presence of other metal ions.

Liquid-crystalline dendrimer Cu(II) complexes and Cu(0) nanoclusters based on the Cu(II) complexes: An electron paramagnetic resonance investigation

NASA Astrophysics Data System (ADS)

Domracheva, N. E.; Mirea, A.; Schwoerer, M.; Torre-Lorente, L.; Lattermann, G.

2007-07-01

New nanostructured materials, namely, the liquid-crystalline copper(II) complexes that contain poly(propylene imine) dendrimer ligands of the first (ligand 1) and second (ligand 2) generations and which have a columnar mesophase and different copper contents (x = Cu/L), are investigated by EPR spectroscopy. The influence of water molecules and nitrate counterions on the magnetic properties of complex 2 (x = 7.3) is studied. It is demonstrated that water molecules can extract some of the copper ions from dendrimer complexes and form hexaaqua copper complexes with free ions. The dimer spectra of fully hydrated complex 2 (x = 7.3) are observed at temperatures T < 10 K. For this complex, the structure is identified and the distance between the copper ions is determined. It is shown that the nitrate counterion plays the role of a bridge between the hexaaqua copper(II) complex and the dendrimer copper(II) complex. The temperature-induced valence tautomerism attended by electron transport is revealed for the first time in blue dendrimer complexes 1 (x = 1.9) with a dimer structure. The activation energy for electron transport is estimated to be 0.35 meV. The coordination of the copper ion site (NO4) and the structural arrangement of green complexes 1 (x = 1.9) in the columnar mesophase are determined. Complexes of this type form linear chains in which nitrate counterions serve as bridges between copper centers. It is revealed that green complexes 1 (x = 1.9) dissolved in isotropic inert solvents can be oriented in the magnetic field (B 0 = 8000 G). The degree of orientation of these complexes is rather high (S z = 0.76) and close to that of systems with a complete ordering (S z = 1) in the magnetic field. Copper(0) nanoclusters prepared by reduction of complex 2 (x = 7.3) in two reducing agents (NaBH4, N2H4 · H2O) are examined. A model is proposed for a possible location of Cu(0) nanoclusters in a dendrimer matrix.

Determining the Fate and Ecological Effects of Copper and Zinc Loading in Estuarine Environments: A Multi-Disciplinary Program

DTIC Science & Technology

2005-12-01

from Centro de Investigación Científica y de Estudios Avanzados de Ensenada. vii viii 1 EXECUTIVE...Fouling, San Diego, California, 21-26 July 2002. Seligman, P.F., A.O. Valkirs, J.S. Caso , I. Rivera-Duarte, and E. Haslbeck, 2001. Copper release rates...EPA-822-R-02-047. Valkirs, A.O., Seligman, P.F., Haslbeck, E., and Caso , J.S., 2003. Measurement of copper release rates from antifouling paint

Statistical Characterization of 18650-Format Lithium-Ion Cell Thermal Runaway Energy Distributions

NASA Technical Reports Server (NTRS)

Walker, William Q.; Rickman, Steven; Darst, John; Finegan, Donal; Bayles, Gary; Darcy, Eric

2017-01-01

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) and moderate energy (200 Wh/kg) 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 1/4m). 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.

Following the movement of Cu ions in a SSZ-13 zeolite during dehydration, reduction and adsorption: a combined in situ TP-XRD, XANES/DRIFTS study

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

Kwak, Ja Hun; Varga, Tamas; Peden, Charles HF

2014-05-05

Cu-SSZ-13 has been shown to possess high activity and superior N2 formation selectivity in the selective catalytic reduction of NOx under oxygen rich conditions. Here, a combination of synchrotron-based (XRD and XANES) and vibrational (DRIFTS) spectroscopy tools have been used to follow the changes in the location and coordination environment of copper ions in a Cu-SSZ-13 zeolite during calcinations, reduction with CO, and adsorption of CO and H2O. XANES spectra collected during these procedures provides critical information not only on the variation in the oxidation state of the copper species in the zeolite structure, but also on the changes inmore » the coordination environment around these ions as they interact with the framework, and with different adsorbates (H2O and CO). Time-resolved XRD data indicate the movement of copper ions and the consequent variation of the unit cell parameters during dehydration. DRIFT spectra provide information about the adsorbed species present in the zeolite, as well as the oxidation states of and coordination environment around the copper ions. A careful analysis of the asymmetric T-O-T vibrations of the CHA framework perturbed by copper ions in different coordination environments proved to be especially informative. The results of this study will aid the identification of the location, coordination and oxidation states of copper ions obtained during in operando catalytic studies. Financial support was provided by the US Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program. Part of this work (sample preparation) was performed in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The EMSL is a national scientific user facility supported by the US DOE, Office of Biological and Environmental Research. PNNL is a multi-program national laboratory operated for the US DOE by Battelle. All of the spectroscopy work reported here was carried out at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL). NSLS is a national scientific user facility supported by the US DOE.« less

Pyrazolate-based copper(II) and nickel(II) [2 x 2] grid complexes: protonation-dependent self-assembly, structures and properties.

PubMed

Klingele, Julia; Prikhod'ko, Alexander I; Leibeling, Guido; Demeshko, Serhiy; Dechert, Sebastian; Meyer, Franc

2007-05-28

The pyrazole-based diamide ligand N,N'-bis(2-pyridylmethyl)pyrazole-3,5-dicarboxamide (H(3)L) has been structurally characterised and successfully employed in the preparation of [2 x 2] grid-type complexes. Thus, the reaction of H(3)L with Cu(ClO(4))2.6H(2)O or Ni(ClO(4))2.6H(2)O in the presence of added base (NaOH) affords the tetranuclear complexes [M(4)(HL(4))].8H(2)O (1: M = Cu, 2: M = Ni). Employment of a mixture of the two metal salts under otherwise identical reaction conditions leads to the formation of the mixed-metal species [Cu(x)Ni(4-x)(HL)(4)].8H(2)O (x

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...

Copper and Lead Corrosion in a Full Scale Home Plumbning system Simulation

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 elevated lead and copper levels to blue water and copper pinhole leaks. If left untreate...

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.

Separation of selenium species released from Se-exposed algae

USGS Publications Warehouse

Besser, John M.; Huckins, James N.; Clark, Randal C.

1994-01-01

We have assessed a fractionation scheme for selenium species that separates Se-containing amino acids and other organoselenium compounds in aqueous samples. We investigated the retention of standard solutions of selenate (Se+6), selenite (Se+4), and selenomethionine (Se−2) by fractionation media (Sephadex A-25 ion-exchange resin, copper-treated Chelex-100 ligand-exchange resin, and activated charcoal) and by several types of membrane filters. The fractionation method successfully isolated Se from the standard solutions into appropriate fractions for radiometric quantitation of 75Se. However, some filter media retained unacceptably large amounts of selenate and selenite. Mass balance microcosms were inoculated with green algae (Chlamydomonas">Chlamydomonasreinhardtii">reinhardtii) previously exposed to inorganic 75Se, and the fractionation scheme was used to examine the release of 75Se species into water and air. The results of the microcosm exposure indicate that seasonal blooms and crashes of phytoplankton populations may produce increased concentrations of organoselenium species.

Ice Melting to Release Reactants in Solution Syntheses.

PubMed

Wei, Hehe; Huang, Kai; Zhang, Le; Ge, Binghui; Wang, Dong; Lang, Jialiang; Ma, Jingyuan; Wang, Da; Zhang, Shuai; Li, Qunyang; Zhang, Ruoyu; Hussain, Naveed; Lei, Ming; Liu, Li-Min; Wu, Hui

2018-03-19

Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO 3 was frozen and dropped into a reductive NaBH 4 solution at about 0 °C. The ultra-slow release of reactants was successfully achieved. An ice-melting process can be used to synthesize atomically dispersed metals, including cobalt, nickel, copper, rhodium, ruthenium, palladium, silver, osmium, iridium, platinum, and gold, which can be easily extended to other solution syntheses (such as precipitation, hydrolysis, and displacement reactions) and provide a generalized method to redesign the interphase reaction kinetics and ion diffusion in wet chemistry. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

A Robust Analytical Approach for the Identification of Specific Protein Carbonylation Sites: Metal-Catalyzed Oxidations of Human Serum Albumin

PubMed Central

Ugur, Zafer; Gronert, Scott

2017-01-01

The formation of protein carbonyls in the metal-catalyzed oxidation of human serum albumin (HSA) is characterized using a new analytical approach that involves tagging the modification site with multiple hydrazide reagents. Protein carbonyl formation at lysine and arginine residues was catalyzed with copper and iron ions, and the resulting oxidation patterns in HSA are contrasted. A total of 18 modification sites were identified with iron ion catalysis and 14 with copper ion catalysis. However, with the more stringent requirement of identification with at least two tagging reagents, the number of validated modification sites drops to 10 for iron and 9 for copper. Of the 14 total validated sites, there were only five in common for the two metal ions. The results illustrate the value of using multiple tagging agents and highlight the selective and specific nature of metal-catalyzed protein oxidations. PMID:28303033

Utilization of turkey manure as granular activated carbon: physical, chemical and adsorptive properties.

PubMed

Lima, Isabel; Marshall, Wayne E

2005-01-01

The high availability of large quantities of turkey manure generated from turkey production makes it an attractive feedstock for carbon production. Pelletized samples of turkey litter and cake were converted to granular activated carbons (GACs) by steam activation. Water flow rate and activation time were changed to produce a range of activation conditions. The GACs were characterized for select physical (yield, surface area, bulk density, attrition), chemical (pH, surface charge) and adsorptive properties (copper ion uptake). Carbon physical and adsorptive properties were dependent on activation time and quantity of steam used as activant. Yields varied from 23% to 37%, surface area varied from 248 to 472 m(2)/g and copper ion adsorption varied from 0.72 to 1.86 mmol Cu(2+)/g carbon. Copper ion adsorption greatly exceeded the values for two commercial GACs. GACs from turkey litter and cake show considerable potential to remove metal ions from water.

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.

Suspension Flame Spray Construction of Polyimide-Copper Layers for Marine Antifouling Applications

NASA Astrophysics Data System (ADS)

Liu, Yi; Xu, Xiaomin; Suo, Xinkun; Gong, Yongfeng; Li, Hua

2018-01-01

Individual capsule-like polyimide splats have been fabricated by suspension flame spray, and the polyimide splat exhibits hollow structure with an inner pore and a tiny hole on its top surface. Enwrapping of 200-1000-nm copper particles inside the splats is accomplished during the deposition for constrained release of copper for antifouling performances. Antifouling testing of the coatings by 24-h exposure to Escherichia coli-containing artificial seawater shows that the Cu-doped splat already prohibits effectively attachment of the bacteria. The prohibited adhesion of bacteria obviously impedes formation and further development of bacterial biofilm. This capsulated splat with releasing and loading of copper biocides results in dual-functional structures bearing both release-killing and contact-killing mechanisms. The suspension flame spray route and the encapsulated structure of the polyimide-Cu coatings would open a new window for designing and constructing marine antifouling layers for long-term applications.

Copper doping of ZnO crystals by transmutation of 64Zn to 65Cu: An electron paramagnetic resonance and gamma spectroscopy study

NASA Astrophysics Data System (ADS)

Recker, M. C.; McClory, J. W.; Holston, M. S.; Golden, E. M.; Giles, N. C.; Halliburton, L. E.

2014-06-01

Transmutation of 64Zn to 65Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5 keV gamma ray from the 65Zn decay and the positron annihilation peak at 511 keV. Their presence confirmed the successful transmutation of 64Zn nuclei to 65Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu2+ ions (where 63Cu and 65Cu hyperfine lines are easily resolved). A spectrum from isolated Cu2+ (3d9) ions acquired after the neutron irradiation showed only hyperfine lines from 65Cu nuclei. The absence of 63Cu lines in this Cu2+ spectrum left no doubt that the observed 65Cu signals were due to transmuted 65Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu+-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu+-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900 °C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

Structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative and its mononuclear and trinuclear copper(II)-coordinated compounds: A combined theoretical and experimental study

NASA Astrophysics Data System (ADS)

Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

2014-11-01

Multicopper oxidases are fundamental in a variety of biological processes in bacteria, fungi and vertebrates. The catalytic center in these enzymes is formed basically by three copper ions, bridged by oxygen bonds. In order to get insights into the reactivity of these complex systems, biomimetic compounds are usually synthesized. Accordingly, in this work, we studied structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative, as well as its corresponding mononuclear and trinuclear copper(II)-coordinated complexes by means of density functional theory. The calculations are compared with experimental results using measurements of the infrared spectra. It is obtained that the molecular configuration of the pseudoephedrine amino-alcohol derivative is stabilized by hydrogen bonding Osbnd H⋯N and by Csbnd H⋯π interactions that are not present in the mononuclear and trinuclear compounds. The coordination compounds show octahedral and square pyramid geometries, respectively, which are slightly distorted by Jahn-Teller effects. The analysis of their theoretical and experimental IR spectra reveals signals related with hydrogen bonding as well as metal-ligand vibrational modes. Regarding the electronic structure, the density of states was calculated in order to analyze the atomic orbital contributions present in these compounds. This analysis would provide useful insights about the optical behavior, for example, in the visible region of the spectrum of the coordinated compounds. At these energies, the optical absorption would be influenced by the orbital interaction of the Cu2+d orbitals with sp ones of the ligand, reflecting a decrease of the HOMO-LUMO gap of the organic ligand due to the presence of the copper(II) ions.

Statistical Evaluation and Optimization of Factors Affecting the Leaching Performance of Copper Flotation Waste

PubMed Central

Çoruh, Semra; Elevli, Sermin; Geyikçi, Feza

2012-01-01

Copper flotation waste is an industrial by-product material produced from the process of manufacturing copper. The main concern with respect to landfilling of copper flotation waste is the release of elements (e.g., salts and heavy metals) when in contact with water, that is, leaching. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals, such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study is to investigate the leaching characteristics of copper flotation waste by use of the Box-Behnken experimental design approach. In order to obtain the optimized condition of leachability, a second-order model was examined. The best leaching conditions achieved were as follows: pH = 9, stirring time = 5 min, and temperature = 41.5°C. PMID:22629194

Statistical evaluation and optimization of factors affecting the leaching performance of copper flotation waste.

PubMed

Coruh, Semra; Elevli, Sermin; Geyikçi, Feza

2012-01-01

Copper flotation waste is an industrial by-product material produced from the process of manufacturing copper. The main concern with respect to landfilling of copper flotation waste is the release of elements (e.g., salts and heavy metals) when in contact with water, that is, leaching. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals, such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study is to investigate the leaching characteristics of copper flotation waste by use of the Box-Behnken experimental design approach. In order to obtain the optimized condition of leachability, a second-order model was examined. The best leaching conditions achieved were as follows: pH = 9, stirring time = 5 min, and temperature = 41.5 °C.

Copper-silver ionization at a US hospital: interaction of treated drinking water with plumbing materials, aesthetics and other considerations

EPA Science Inventory

Tap water sampling and surface analysis of copper pipe/bathroom porcelain were performed to explore the fate of copper and silver during the first nine months of copper-silver ionization (CSI) applied to cold and hot water at a hospital in Cincinnati, Ohio. Ions dosed by CSI into...

Effects of chemical composition on the corrosion of dental alloys.

PubMed

Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Rocha, Luís Augusto; de Mattos, Maria da Glória Chiarello

2012-01-01

The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.

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.

Hydrothermal preparation of copper doped NaTaO3 nanoparticles and study on the photocatalytic mechanism.

PubMed

Liu, Yulu; Su, Yiguo; Han, Hui; Wang, Xiaojing

2013-02-01

Effects of copper cations doping into wide band gap semiconductor photocatalysts of tantalate on morphology, visible light response, and photocatalytic performance were studied. A series of Cu-doped NaTaO3 catalysts were prepared by hydrothermal method. XRD and XPS results suggested that copper were successfully doped into the NaTaO3 nanocrystal in the Cu2+ state. TEM studies showed the formation of the cube shape nanoparticles of NaTaO3 as well as Cu-doped NaTaO3. UV-Vis diffuse reflectance spectra clearly indicated the red-shift in the series of copper doped NaTaO3 catalysts, resulting in a decrease in the band gap of NaTaO3. The trend of red shift was increased with an increase of copper doping concentration, whereas the photo-degradation methylene blue (MB) is not improved by the doping of copper ions. The simulation of energy band structure by density functional theory unfolded that the substitution of Ta5+ ions by Cu2+ ions results in forming an intermediate band (IB) upper the top of the valence band (VB), which is mainly attributed to the state of Cu 3d. The intermediate band is responsible for the red-shift caused by the doping of Cu ions. Meanwhile Cu species can become the recombination centers of photoinduced electrons and holes. Thus, the quickly recombination of e(-)h(+) pairs is one of the most significant factors which deteriorate the photoactivity of Cu-doped NaTaO3.

Combustion synthesized copper-ion substituted FeAl2O4 (Cu0.1Fe0.9Al2O4): A superior catalyst for methanol steam reforming compared to its impregnated analogue

NASA Astrophysics Data System (ADS)

Maiti, Sayantani; Llorca, Jordi; Dominguez, Montserrat; Colussi, Sara; Trovarelli, Alessandro; Priolkar, Kaustubh R.; Aquilanti, Giuliana; Gayen, Arup

2016-02-01

A series of copper ion substituted MAl2O4 (M = Mg, Mn, Fe and Zn) spinels is prepared by a single step solution combustion synthesis (SCS) and tested for methanol steam reforming (MSR). The copper ion substituted Cu0.1Fe0.9Al2O4 appears to be the most active, showing ∼98% methanol conversion at 300 °C with ∼5% CO selectivity at GHSV = 30,000 h-1 and H2O:CH3OH = 1.1. The analogous impregnated catalyst, CuO (10 at%)/FeAl2O4, is found to be much less active. These materials are characterized by XRD, H2-TPR, BET, HRTEM, XPS and XANES analyses. Spinel phase formation is highly facilitated upon Cu-ion substitution and Cu loading beyond 10 at% leads to the formation of CuO as an additional phase. The ionic substitution of copper in FeAl2O4 leads to the highly crystalline SCS catalyst containing Cu2+ ion sites that are shown to be more active than the dispersed CuO nano-crystallites on the FeAl2O4 impregnated catalyst, despite its lower surface area. The as prepared SCS catalyst contains also a portion of copper as Cu1+ that increases when subjected to reforming atmosphere. The MSR activity of the SCS catalyst decreases with time-on-stream due to the sintering of catalyst crystallites as established from XPS and HRTEM analyses.

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.

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 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...

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.

Different roles of glutathione in copper and zinc chelation in Brassica napus roots.

PubMed

Zlobin, Ilya E; Kartashov, Alexander V; Shpakovski, George V

2017-09-01

We investigated the specific features of copper and zinc excess action on the roots of canola (Brassica napus L.) plants. Copper rapidly accumulated in canola root cells and reached saturation during several hours of treatment, whereas the root zinc content increased relatively slowly. Excessive copper and zinc entry inside the cell resulted in significant cell damage, as evidenced by alterations in plasmalemma permeability and decreases in cellular enzymatic activity. Zinc excess specifically damaged root hair cells, which correlated with a pronounced elevation of their labile zinc level. In vitro, we showed that reduced glutathione (GSH) readily reacted with copper ions to form complexes with blocked sulfhydryl groups. In contrast, zinc ions were ineffective as glutathione blockers, and glutathione molecules did not lose their specific chemical activity in the presence of Zn 2+ ions. The effect of copper and zinc excess on the glutathione pool in canola root cells was analysed by a combination of biochemical determination of total and oxidized glutathione contents and fluorescent staining of free reduced glutathione with monochlorobimane dye. Excess copper led to dose-dependent diminution of free reduced glutathione contents in the root cells, which could not be explained by the loss of total cellular glutathione or its oxidation. In contrast, we observed little effect of much higher intracellular zinc concentrations on the free reduced glutathione content. We concluded that GSH plays an important role in copper excess, but not zinc excess chelation, in canola root cells. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Assessment and modification of an ion source grid design in KSTAR neutral beam system.

PubMed

Lee, Dong Won; Shin, Kyu In; Jin, Hyung Gon; Choi, Bo Guen; Kim, Tae-Seong; Jeong, Seung Ho

2014-02-01

A new 2 MW NB (Neutral Beam) ion source for supplying 3.5 MW NB heating for the KSTAR campaign was developed in 2012 and its grid was made from OFHC (Oxygen Free High Conductivity) copper with rectangular cooling channels. However, the plastic deformation such as a bulging in the plasma grid of the ion source was found during the overhaul period after the 2012 campaign. A thermal-hydraulic and a thermo-mechanical analysis using the conventional code, ANSYS, were carried out and the thermal fatigue life assessment was evaluated. It was found that the thermal fatigue life of the OFHC copper grid was about 335 cycles in case of 0.165 MW/m(2) heat flux and it gave too short fatigue life to be used as a KSTAR NB ion source grid. To overcome the limited fatigue life of the current design, the following methods were proposed in the present study: (1) changing the OHFC copper to CuCrZr, copper-alloy or (2) adopting a new design with a pure Mo metal grid and CuCrZr tubes. It is confirmed that the proposed methods meet the requirements by performing the same assessment.

First-principles surface interaction studies of aluminum-copper and aluminum-copper-magnesium secondary phases in aluminum alloys

NASA Astrophysics Data System (ADS)

da Silva, Thiago H.; Nelson, Eric B.; Williamson, Izaak; Efaw, Corey M.; Sapper, Erik; Hurley, Michael F.; Li, Lan

2018-05-01

First-principles density functional theory-based calculations were performed to study θ-phase Al2Cu, S-phase Al2CuMg surface stability, as well as their interactions with water molecules and chloride (Cl-) ions. These secondary phases are commonly found in aluminum-based alloys and are initiation points for localized corrosion. Density functional theory (DFT)-based simulations provide insight into the origins of localized (pitting) corrosion processes of aluminum-based alloys. For both phases studied, Cl- ions cause atomic distortions on the surface layers. The nature of the distortions could be a factor to weaken the interlayer bonds in the Al2Cu and Al2CuMg secondary phases, facilitating the corrosion process. Electronic structure calculations revealed not only electron charge transfer from Cl- ions to alloy surface but also electron sharing, suggesting ionic and covalent bonding features, respectively. The S-phase Al2CuMg structure has a more active surface than the θ-phase Al2Cu. We also found a higher tendency of formation of new species, such as Al3+, Al(OH)2+, HCl, AlCl2+, Al(OH)Cl+, and Cl2 on the S-phase Al2CuMg surface. Surface chemical reactions and resultant species present contribute to establishment of local surface chemistry that influences the corrosion behavior of aluminum alloys.

Yeast Starter as a Biotechnological Tool for Reducing Copper Content in Wine

PubMed Central

Capece, Angela; Romaniello, Rossana; Scrano, Laura; Siesto, Gabriella; Romano, Patrizia

2018-01-01

Copper is widely used in agriculture as a traditional fungicide in organic farming to control downy mildew on grapes, consequently it is possible to find this metal during all stages of the vinification process. Low amounts of copper play a key role on the function of key cell enzymes, whereas excess quantities can exert amount-dependent cytotoxicity, resulting in general cellular damage. Nowadays the excessive copper ions in wines is removed by addition of adsorbents, but these additives can influence the sensory characteristics of wine, as well as detrimental to the health of consumers. It is well known that high concentrations of Cu2+ can be toxic to yeasts, inhibiting growth and activity, causing sluggish fermentation and reducing alcohol production. In this study, 47 S. cerevisiae strains were tested for copper tolerance by two different tests, growth on copper added medium and fermentative activity in copper added grape must. The results obtained by the two different tests were comparable and the high strain variability found was used to select four wild strains, possessing this characteristic at the highest (PP1-13 and A20) and the lowest level (MPR2-24 and A13). The selected strains were tested in synthetic and natural grape must fermentation for ability to reduce copper content in wine. The determination of copper content in wines and yeast cells revealed that at the lowest copper residual in wine corresponded the highest content in yeast cells, indicating a strong strain ability to reduce the copper content in wine. This effect was inversely correlated with strain copper resistance and the most powerful strain in copper reduction was the most sensitive strain, MPR2-24. This wild strain was finally tested as starter culture in cellar pilot scale fermentation in comparison to a commercial starter, confirming the behavior exhibited at lab scale. The use of this wild strain to complete the alcoholic fermentation and remove the copper from wine represents a biotechnological sustainable approach, as alternative to the chemical-physical methods, ensuring at the same time a completed alcoholic fermentation and organoleptic quality of wine. PMID:29375502

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.

Surface Induced Dissociation Coupled with High Resolution Mass Spectrometry Unveils Heterogeneity of a 211 kDa Multicopper Oxidase Protein Complex

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

Zhou, Mowei; Yan, Jing; Romano, Christine A.

Manganese oxidation is an important biogeochemical process that is largely regulated by bacteria through enzymatic reactions. However, the detailed mechanism is poorly understood due to challenges in isolating and characterizing these unknown enzymes. A manganese oxidase Mnx from Bacillus sp. PL-12 has been successfully overexpressed in active form, unexpectedly, as a protein complex with a molecular weight of 211 kDa with no homology to known proteins in the database. We have recently used surface induced dissociation (SID) and ion mobility – mass spectrometry (IM-MS) to release and detect folded subcomplexes for determining subunit connectivity and quaternary structure. The data frommore » the native mass spectrometry experiment led to a plausible model of this unknown multicopper oxidase which has been difficult to study by conventional structural biology methods. However, because each subunit of Mnx binds copper ions as cofactor at varying ratios, there were remaining ambiguities in assigning some of the observed peaks to metal-binding species because of the sample heterogeneity and limited mass resolution. In this study, we performed SID in a modified Fourier transform – ion cyclotron resonance (FT-ICR) mass spectrometer for obtaining the ultimate resolution on the released subcomplexes of Mnx. The high mass accuracy and resolution unveiled unexpected artificial modifications in the protein that have been previously thought to be iron bound species based on lower resolution data. Additionally, most released subcomplexes were isotopically resolved for defining metal binding stoichiometry at each structural level. This method holds great potential for in-depth characterization of metalloproteins and protein-ligand complexes.« less

Streptococcus mutans copper chaperone, CopZ, is critical for biofilm formation and competitiveness.

PubMed

Garcia, S S; Du, Q; Wu, H

2016-12-01

The oral cavity is a dynamic environment characterized by hundreds of bacterial species, saliva, and an influx of nutrients and metal ions such as copper. Although there is a physiologic level of copper in the saliva, the oral cavity is often challenged with an influx of copper ions. At high concentrations copper is toxic and must therefore be strictly regulated by pathogens for them to persist and cause disease. The cariogenic pathogen Streptococcus mutans manages excess copper using the copYAZ operon that encodes a negative DNA-binding repressor (CopY), the P1-ATPase copper exporter (CopA), and the copper chaperone (CopZ). These hypothetical roles of the copYAZ operon in regulation and copper transport to receptors led us to investigate their contribution to S. mutans virulence. Mutants defective in the copper chaperone CopZ, but not CopY or CopA, were impaired in biofilm formation and competitiveness against commensal streptococci. Characterization of the CopZ mutant biofilm revealed a decreased secretion of glucosyltransferases and reduced expression of mutacin genes. These data suggest that the function of copZ on biofilm and competitiveness is independent of copper resistance and CopZ is a global regulator for biofilm and other virulence factors. Further characterization of CopZ may lead to the identification of new biofilm pathways. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Phototherapeutic spectrum expansion through synergistic effect of mesoporous silica trio-nanohybrids against antibiotic-resistant gram-negative bacterium.

PubMed

Kuthati, Yaswanth; Kankala, Ranjith Kumar; Busa, Prabhakar; Lin, Shi-Xiang; Deng, Jin-Pei; Mou, Chung-Yuan; Lee, Chia-Hung

2017-04-01

The extensive impact of antibiotic resistance has led to the exploration of new anti-bacterial modalities. We designed copper impregnated mesoporous silica nanoparticles (Cu-MSN) with immobilizing silver nanoparticles (SNPs) to apply photodynamic inactivation (PDI) of antibiotic-resistant E. coli. SNPs were decorated over the Cu-MSN surfaces by coordination of silver ions on diamine-functionalized Cu-MSN and further reduced to silver nanoparticles with formalin. We demonstrate that silver is capable of sensitizing the gram-negative bacteria E. coli to a gram-positive specific phototherapeutic agent in vitro; thereby expanding curcumin's phototherapeutic spectrum. The mesoporous structure of Cu-MSN remains intact after the exterior decoration with silver nanoparticles and subsequent curcumin loading through an enhanced effect from copper metal-curcumin affinity interaction. The synthesis, as well as successful assembly of the functional nanomaterials, was confirmed by various physical characterization techniques. Curcumin is capable of producing high amounts of reactive oxygen species (ROS) under light irradiation, which can further improve the silver ion release kinetics for antibacterial activity. In addition, the positive charged modified surfaces of Cu-MSN facilitate antimicrobial response through electrostatic attractions towards negatively charged bacterial cell membranes. The antibacterial action of the synthesized nanocomposites can be activated through a synergistic mechanism of energy transfer of the absorbed light from SNP to curcumin. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of the Bridging Ligand in the Active Site of Tyrosinase.

PubMed

Zou, Congming; Huang, Wei; Zhao, Gaokun; Wan, Xiao; Hu, Xiaodong; Jin, Yan; Li, Junying; Liu, Junjun

2017-10-28

Tyrosinase is a type-3 copper enzyme that is widely distributed in plants, fungi, insects, and mammals. Developing high potent inhibitors against tyrosinase is of great interest in diverse fields including tobacco curing, food processing, bio-insecticides development, cosmetic development, and human healthcare-related research. In the crystal structure of Agaricus bisporus mushroom tyrosinase, there is an oxygen atom bridging the two copper ions in the active site. It is unclear whether the identity of this bridging oxygen is a water molecule or a hydroxide anion. In the present study, we theoretically determine the identity of this critical bridging oxygen by performing first-principles hybrid quantum mechanics/molecular mechanics/Poisson-Boltzmann-surface area (QM/MM-PBSA) calculations along with a thermodynamic cycle that aim to improve the accuracy. Our results show that the binding with water molecule is energy favored and the QM/MM-optimized structure is very close to the crystal structure, whereas the binding with hydroxide anions causes the increase of energy and significant structural changes of the active site, indicating that the identity of the bridging oxygen must be a water molecule rather than a hydroxide anion. The different binding behavior between water and hydroxide anions may explain why molecules with a carboxyl group or too many negative charges have lower inhibitory activity. In light of this, the design of high potent active inhibitors against tyrosinase should satisfy both the affinity to the copper ions and the charge neutrality of the entire molecule.

Preparation and adsorption characteristics for heavy metals of active silicon adsorbent from leaching residue of lead-zinc tailings.

PubMed

Lei, Chang; Yan, Bo; Chen, Tao; Xiao, Xian-Ming

2018-05-19

To comprehensively reuse the leaching residue obtained from lead-zinc tailings, an active silicon adsorbent (ASA) was prepared from leaching residue and studied as an adsorbent for copper(II), lead(II), zinc(II), and cadmium(II) in this paper. The ASA was prepared by roasting the leaching residue with either a Na 2 CO 3 /residue ratio of 0.6:1 at 700 °C for 1 h or a CaCO 3 /residue ratio of 0.8:1 at 800 °C for 1 h. Under these conditions, the available SiO 2 content of the ASA was more than 20%. The adsorption behaviors of the metal ions onto the ASA were investigated and the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were used to analyze the adsorption isotherm. The result showed that the maximum adsorption capacities of copper(II), lead(II), cadmium(II), and zinc(II) calculated by the Langmuir model were 3.40, 2.83, 0.66, and 0.62 mmol g -1 , respectively. The FT-IR spectra of the ASA and the mean free adsorption energies indicated that ion exchange was the mechanism of copper(II), lead(II), and cadmium(II) adsorption and that chemical reaction was the mechanism of zinc(II) adsorption. These results provide a method for reusing the leaching residue obtained from lead-zinc tailings and show that the ASA is an effective adsorbent for heavy metal pollution remediation.

Specific anion effects on copper surface through electrochemical treatment: Enhanced photoelectrochemical CO2 reduction activity of derived nanostructures induced by chaotropic anions

NASA Astrophysics Data System (ADS)

Navaee, Aso; Salimi, Abdollah

2018-05-01

Copper derivatives are the most prominent CO2 reduction electrocatalyst. Herein, the metallic copper has been electrochemically treated with some of common ionic salts such as N3bar, HPO2bar, S2bar, Fbar, Clbar, Brbar and Ibar based on the dissolution of a metallic working electrode in an aqueous solution to derive the surface roughness incorporated with nanostructures. Diverse surface morphology can be obtained when the ionic radii of anions are changed. Surface study reveals various roughness shapes based on the size and polarity of the anions, where the ions with higher ionic radii have higher impact on the Cu surface. In comparison, polyatomic oxyanion such as HPO2bar even with large ionic radii do not have enough strength to create the surface roughness than that of oxygen-free anions with large ionic radii. The photoelectrochemical behavior of the modified surfaces toward CO2 reduction is studied at a wide potential window in bicarbonate aqueous solution. Based on our investigations, treated surfaces by Ibar, Clbar and S2bargive a more surface roughness, while Ibar and N3bar offer higher catalytic activity toward CO2 reduction due to possible complexing ability of these anions with Cu cations, followed by formation of the co-catalyst semiconductor and facilitate electron transfer. This methodology can be applied to investigate the effect of ions on transition metals along with obtaining different surface morphologies tailored to different applications.

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...

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

Rudeck, P.J.; Harper, J.M.E.; Fryer, P.M.

The copper concentration in aluminum--copper alloys can be altered by ion bombardment during film deposition. We have measured the sputtering yields of aluminum and copper in Al--Cu alloys as a function of the Cu concentration (5--13 at. %) and the angle of ion incidence (0--40/sup 0/ from normal). During deposition, the films were partially resputtered by 500-eV Ar/sup +/ ion bombardment from a Kaufman ion source. We found that the Cu sputtering yield decreases by up to a factor of 10 in the alloy, relative to elemental Cu. The Al sputtering yield remains close to the elemental value. The netmore » effect is a strong preferential sputtering of Al relative to Cu, which enhances the Cu concentration in an ion bombarded film. The Al/Cu sputtering yield ratio for normal incidence ion bombardment ranges from 3 to 5 as a function of Cu concentration. This ratio decreases with increasing angle of incidence to as low as 2 for 40/sup 0/ incident ions. However, since a higher fraction of the film is resputtered from a sloping surface, a higher Cu concentration is found on a sloping surface relative to a flat surface. These results show that in multicomponent film deposition under ion bombardment, the film composition will vary as a function of the surface topography. We will also show how the level of argon left trapped in the films varies inversely with respect to the ion flux.« less

X-ray-induced fluorescent centers formation in zinc- phosphate glasses doped with Ag and Cu ions

NASA Astrophysics Data System (ADS)

Klyukin, D. A.; Pshenova, A. S.; Sidorov, A. I.; Stolyarchuk, M. V.

2016-08-01

Fluorescent properties of silver and copper doped zinc-phosphate glasses were studied. By X-ray irradiation of silver and copper co-doped glasses we could create and identify new emission centers which do not exist in single-doped samples. Doping of the glass with both silver and copper ions leads to the increase of quantum yield by 2.7 times. The study was complemented by quantum chemical calculations using the time-dependent density functional theory. It was shown that fluorescence may be attributed to the formation of mixed Ag-Cu molecular clusters.

Surface Structures Formed by a Copper(II) Complex of Alkyl-Derivatized Indigo

PubMed Central

Honda, Akinori; Noda, Keisuke; Tamaki, Yoshinori; Miyamura, Kazuo

2016-01-01

Assembled structures of dyes have great influence on their coloring function. For example, metal ions added in the dyeing process are known to prevent fading of color. Thus, we have investigated the influence of an addition of copper(II) ion on the surface structure of alkyl-derivatized indigo. Scanning tunneling microscope (STM) analysis revealed that the copper(II) complexes of indigo formed orderly lamellar structures on a HOPG substrate. These lamellar structures of the complexes are found to be more stable than those of alkyl-derivatized indigos alone. Furthermore, 2D chirality was observed. PMID:28773957

Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole.

PubMed

Kalanithi, M; Rajarajan, M; Tharmaraj, P; Sheela, C D

2012-02-15

Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol(HL(1)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol(HL(2)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol(HL(3)). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry. Copyright © 2011 Elsevier B.V. All rights reserved.

How much arsenic is released when CCA wood is burned?

Treesearch

Charles K. McMahon; Parshall B. Bush; Edwin A. Woolson

1986-01-01

Abstract. Waterborne salts have been used to preserve wood for many years. One of the more common formulations contains copper, chromium, and arsenic salts and is known as chromated copper arsenate, or CCA. Questions have been raised about the amount of arsenic released when CCA treated wood is burned in wood stoves, fireplaces, or boilers....

Probing the Production of Amidated Peptides following Genetic and Dietary Copper Manipulations

PubMed Central

Yin, Ping; Bousquet-Moore, Danielle; Annangudi, Suresh P.; Southey, Bruce R.; Mains, Richard E.; Eipper, Betty A.; Sweedler, Jonathan V.

2011-01-01

Amidated neuropeptides play essential roles throughout the nervous and endocrine systems. Mice lacking peptidylglycine α-amidating monooxygenase (PAM), the only enzyme capable of producing amidated peptides, are not viable. In the amidation reaction, the reactant (glycine-extended peptide) is converted into a reaction intermediate (hydroxyglycine-extended peptide) by the copper-dependent peptidylglycine-α-hydroxylating monooxygenase (PHM) domain of PAM. The hydroxyglycine-extended peptide is then converted into amidated product by the peptidyl-α-hydroxyglycine α-amidating lyase (PAL) domain of PAM. PHM and PAL are stitched together in vertebrates, but separated in some invertebrates such as Drosophila and Hydra. In addition to its luminal catalytic domains, PAM includes a cytosolic domain that can enter the nucleus following release from the membrane by γ-secretase. In this work, several glycine- and hydroxyglycine-extended peptides as well as amidated peptides were qualitatively and quantitatively assessed from pituitaries of wild-type mice and mice with a single copy of the Pam gene (PAM+/−) via liquid chromatography-mass spectrometry-based methods. We provide the first evidence for the presence of a peptidyl-α-hydroxyglycine in vivo, indicating that the reaction intermediate becomes free and is not handed directly from PHM to PAL in vertebrates. Wild-type mice fed a copper deficient diet and PAM+/− mice exhibit similar behavioral deficits. While glycine-extended reaction intermediates accumulated in the PAM+/− mice and reflected dietary copper availability, amidated products were far more prevalent under the conditions examined, suggesting that the behavioral deficits observed do not simply reflect a lack of amidated peptides. PMID:22194882

Effect of calcination temperature of a copper ferrite synthesized by a sol-gel method on its structural characteristics and performance as Fenton catalyst to remove gallic acid from water.

PubMed

López-Ramón, María V; Álvarez, Miguel A; Moreno-Castilla, Carlos; Fontecha-Cámara, María A; Yebra-Rodríguez, África; Bailón-García, Esther

2018-02-01

A copper ferrite synthesized by a sol-gel combustion method was calcined at different temperatures up to 800°C, determining changes in its structural characteristics and magnetic measurements and studying its catalytic performance in gallic acid removal by Fenton reaction. The main objective was to study the effect of the calcination temperature of copper ferrite on its crystalline phase formation and transformation, activity and metal ion leaching. The cubic-to-tetragonal transformation of the spinel occurred via its reaction with the CuO phase, displacing Fe 3+ ions in B (octahedral) sites out of the spinel structure by the following reaction: 2Fe 3+ B +3CuO→Fe 2 O 3 +3Cu 2+ B . The catalysts showed superparamagnetic or substantial superparamagnetic behaviour. At higher calcination temperatures, catalyst activity was lower, and Cu ion leaching was markedly decreased. There was no Fe ion leaching with any catalyst. The as-prepared catalyst showed better catalytic performance than a commercial copper ferrite. Leached Cu ions acted as homogeneous catalysts, and their contribution to the overall removal mechanism was examined. Cu 2 O present in the as-prepared catalysts made only a small contribution to their activity. Finally, the reutilization of various catalysts was studied by performing different catalytic cycles. Copyright © 2017 Elsevier Inc. All rights reserved.

The Impact of Water Quality, Corrosion Inhibitors and Plumbing Age on Copper Release in Distribution Systems

EPA Science Inventory

The U.S. Environmental Protection Agency promulgated the Lead and Copper Rule (LCR) in 1991, which established a copper action level of 1.3 mg/L in the consumers’ tap water. As a result, researchers have examined the effects of water chemistry on the solubility of copper to esta...

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…

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...

iMAST Quarterly, Number 3, 2000

DTIC Science & Technology

2000-01-01

components which depend on evaporating unit capabilities. There are three components (EB-gun, water cooled copper crucible and vacuum chamber) in the EB-PVD...Ion Implantation and Ion Plating electromagnetic deflected through 180 or 2700. Similarly, evaporant material is placed in a water-cooled copper ... crucible , which could be either pocket type for small quantity evaporation application or continuous ingot feeding through the crucible for larger quantity

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.

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...

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.

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

Rudeck, P.J.; Harper, J.M.E.; Fryer, P.M.

The copper concentration in aluminum-copper alloys can be altered by ion bombardment during film deposition. We have measured the sputtering yields of aluminum and copper in Al-Cu alloys as a function of the Cu concentration (5--13 at. %) and the angle of ion incidence (0/sup 0/--40/sup 0/ from normal). During deposition, the films were partially resputtered by 500 eV Ar/sup +/ ion bombardment from a Kaufman ion source. We found that the Cu sputtering yield decreases by up to a factor of 10 in the alloy, relative to elemental Cu. The Al sputtering yield remains close to the elemental value.more » The net effect is a strong preferential sputtering of Al relative to Cu, which enhances the Cu concentration in an ion-bombarded film. The Al/Cu sputtering yield ratio for normal incidence ion bombardment ranges from 3 to 5 as a function of Cu concentration. This ratio decreases with increasing angle of incidence to as low as 2 for 40/sup 0/ incident ions. However, since a higher fraction of the film is resputtered from a sloping surface, a higher Cu concentration is found on a sloping surface relative to a flat surface. These results show that the film composition will vary as a function of the surface topography.« less

Integrated Solid/Nanoporous Copper/Oxide Hybrid Bulk Electrodes for High-performance Lithium-Ion Batteries

PubMed Central

Hou, Chao; Lang, Xing-You; Han, Gao-Feng; Li, Ying-Qi; Zhao, Lei; Wen, Zi; Zhu, Yong-Fu; Zhao, Ming; Li, Jian-Chen; Lian, Jian-She; Jiang, Qing

2013-01-01

Nanoarchitectured electroactive materials can boost rates of Li insertion/extraction, showing genuine potential to increase power output of Li-ion batteries. However, electrodes assembled with low-dimensional nanostructured transition metal oxides by conventional approach suffer from dramatic reductions in energy capacities owing to sluggish ion and electron transport kinetics. Here we report that flexible bulk electrodes, made of three-dimensional bicontinuous nanoporous Cu/MnO2 hybrid and seamlessly integrated with Cu solid current collector, substantially optimizes Li storage behavior of the constituent MnO2. As a result of the unique integration of solid/nanoporous hybrid architecture that simultaneously enhances the electron transport of MnO2, facilitates fast ion diffusion and accommodates large volume changes on Li insertion/extraction of MnO2, the supported MnO2 exhibits a stable capacity of as high as ~1100 mA h g−1 for 1000 cycles, and ultrahigh charge/discharge rates. It makes the environmentally friendly and low-cost electrode as a promising anode for high-performance Li-ion battery applications. PMID:24096928

Electrospray ionization mass spectrometric investigations of the complexation behavior of macrocyclic thiacrown ethers with bivalent transitional metals (Cu, Co, Ni and Zn).

PubMed

Tsybizova, Alexandra; Tarábek, Ján; Buchta, Michal; Holý, Petr; Schröder, Detlef

2012-10-15

Heavy metals are both a problem for the environment and an important resource for industry. Their selective extraction by means of organic ligands therefore is an attractive topic. The coordination of three thiacrown ethers to late 3d-metal ions was investigated by a combination of electrospray ionization mass spectrometry (ESI-MS) and electron paramagnetic resonance (EPR). The mass spectrometric experiments were carried out in an ion trap mass spectrometer with an ESI source. Absolute binding constants were estimated by comparison with data for 18-crown-6/Na(+). EPR spectroscopy was used as a complementary method for investigating the Cu(I) /Cu(II) redox couple. The study found that thiacrown ethers preferentially bind traces of copper even at an excess of other metal ions (Co(II), Ni(II), and Zn(II)). The absolute association constants of the Cu(I) complexes were about 10(8) M(-1), and about two orders of magnitude lower for the other 3d-metal cations. The EPR spectra demonstrated that the reduction from Cu(II) to Cu(I) upon formation of the [(thiacrown)Cu](+) species takes place in solution. ESI-MS demonstrated that the three thiacrown ligands examined had high binding constants as well as good selectivities for copper(I) at low concentrations, and in the presence of other metal ions. By a combination of ESI-MS and EPR spectrometry it was shown that the reduction from Cu(II) to Cu(I) occurred in solution. Copyright © 2012 John Wiley & Sons, Ltd.

Geochemical behavior of heavy metals in a Zn-Pb-Cu mining area in the State of Mexico (central Mexico).

PubMed

Lizárraga-Mendiola, L; González-Sandoval, M R; Durán-Domínguez, M C; Márquez-Herrera, C

2009-08-01

The geochemical behavior of zinc, lead and copper from sulfidic tailings in a mine site with potential to generate acidic drainage (pyrite (55%) and sphalerite (2%)) is reported in this paper. The mining area is divided in two zones, considering the topographic location of sampling points with respect to the tailings pile: (a) outer zone, out of the probable influence of acid mine drainage (AMD) pollution, and (b) inner zone, probably influenced by AMD pollution. Maximum total ions concentrations (mg/L) measured in superficial waters found were, in the outer zone: As (0.2), Cd (0.9), Fe (19), Mn (39), Pb (5.02), SO4(2-) (4650), Zn (107.67), and in the inner zone are As (0.1), Cd (0.2), Fe (88), Mn (13), Pb (6), SO4(2-) (4,880), Zn (46). The presence of these ions that exceeding the permissible maximum limits for human consume, could be associated to tailings mineralogy and acid leachates generated in tailings pile.

Impact of water chemistry on the particle-specific toxicity of copper nanoparticles to Daphnia magna.

PubMed

Xiao, Yinlong; Peijnenburg, Willie J G M; Chen, Guangchao; Vijver, Martina G

2018-01-01

Toxicity of metallic nanoparticle suspensions (NP (total) ) is generally assumed to result from the combined effect of the particles present in suspensions (NP (particle) ) and their released ions (NP (ion) ). Evaluation and consideration of how water chemistry affects the particle-specific toxicity of NP (total) are critical for environmental risk assessment of nanoparticles. In this study, it was found that the toxicity of Cu NP (particle) to Daphnia magna, in line with the trends in toxicity for Cu NP (ion) , decreased with increasing pH and with increasing concentrations of divalent cations and dissolved organic carbon (DOC). Without the addition of DOC, the toxicity of Cu NP (total) to D. magna at the LC50 was driven mainly by Cu NP (ion) (accounting for ≥53% of the observed toxicity). However, toxicity of Cu NP (total) in the presence of DOC at a concentration ranging from 5 to 50mg C/L largely resulted from the NP (particle) (57%-85%), which could be attributable to the large reduction of the concentration of Cu NP (ion) and the enhancement of the stability of Cu NP (particle) when DOC was added. Our results indicate that water chemistry needs to be explicitly taken into consideration when evaluating the role of NP (particle) and NP (ion) in the observed toxicity of NP (total) . Copyright © 2017 Elsevier B.V. All rights reserved.

The determination of copper in biological materials by flame spectrophotometry

PubMed Central

Newman, G. E.; Ryan, M.

1962-01-01

A method for the determination of the copper content of biological materials by flame spectrophotometry is described. The effects of interference by ions such as sodium and phosphate were eliminated by isolating copper as the dithizonate in CCl4. Results obtained for the urinary excretion of copper by a patient with Wilson's disease before and after treatment with penicillamine are reported. PMID:14479334

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.

Syntheses and structural characterization of iron(II) and copper(II) coordination compounds with the neutral flexible bidentate N-donor ligands

NASA Astrophysics Data System (ADS)

Beheshti, Azizolla; Lalegani, Arash; Bruno, Giuseppe; Rudbari, Hadi Amiri

2014-08-01

Two new coordination compounds [Fe(bib)2(N3)2]n(1) and [Cu2(bpp)2(N3)4] (2) with azide and flexible ligands 1,4-bis(imidazolyl)butane (bib) and 1,3-bis(3,5-dimethylpyrazolyl)propane (bpp) were prepared and structurally characterized. In the 2D network structure of 1, the iron(II) ion lies on an inversion center and exhibits an FeN6 octahedral arrangement while in the dinuclear structure of 2, the copper(II) ion adopts an FeN5 distorted square pyramid geometry. In the complex 1, each μ2-bib acts as bridging ligand connecting two adjacent iron(II) ions while in the complex 2, the bpp ligand is coordinated to copper(II) ion in a cyclic-bidentate fashion forming an eight-membered metallocyclic ring. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. Thermal analysis of polymer 1 was also studied.

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.

Exogenous addition of histidine reduces copper availability in the yeast Saccharomyces cerevisiae.

PubMed

Watanabe, Daisuke; Kikushima, Rie; Aitoku, Miho; Nishimura, Akira; Ohtsu, Iwao; Nasuno, Ryo; Takagi, Hiroshi

2014-07-07

The basic amino acid histidine inhibited yeast cell growth more severely than lysine and arginine. Overexpression of CTR1 , which encodes a high-affinity copper transporter on the plasma membrane, or addition of copper to the medium alleviated this cytotoxicity. However, the intracellular level of copper ions was not decreased in the presence of excess histidine. These results indicate that histidine cytotoxicity is associated with low copper availability inside cells, not with impaired copper uptake. Furthermore, histidine did not affect cell growth under limited respiration conditions, suggesting that histidine cytotoxicity is involved in deficiency of mitochondrial copper.

Antifungal evaluation studies of copper sulfide nano-aquaformulations and its impact on seed quality of rice ( Oryzae sativa)

NASA Astrophysics Data System (ADS)

Sidhu, Anjali; Barmota, Heena; Bala, Anju

2017-11-01

Surface capped copper sulfide nano-aquaformulations were prepared by in situ combination of copper ions with sulfide ions using sonochemical method, followed by microwave irradiations, in the presence of capping agents. Prepared nano-aquaformulations were characterized for particle size, morphology and optical properties. The in vitro antifungal evaluations studies indicated multifold efficacy against Alternaria alternata, Drechslera oryzae and Curvularia lunata in comparison to standard used. The in vivo seed treatment on discoloured paddy seeds showed the optimum results on application @ 7μg/ml for 2 h in case of citrate capped copper sulfide nanoformulation (NCuS3). Significant reduction in seed rot and seedling blight was observed with favourable effect on germination and growth parameters at this concentration.

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.

Preparation of Some Novel Copper(I) Complexes and their Molar Conductances in Organic Solvents

NASA Astrophysics Data System (ADS)

Gill, Dip Singh; Rana, Dilbag

2009-04-01

Attempts have been made to prepare some novel copper(I) nitrate, sulfate, and perchlorate complexes. Molar conductances of these complexes have been measured in organic solvents like acetonitrile (AN), acetone (AC), methanol (MeOH), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMA), and dimethylsulfoxide (DMSO) at 298 K. The molar conductance data have been analyzed to obtain limiting molar conductances (λ0) and ion association constants (KA) of the electrolytes. The results showed that all these complexes are strong electrolytes in all organic solvents. The limiting ionic molar conductances (λo± ) for various ions have been calculated using Bu4NBPh4 as reference electrolyte. The actual radii for copper(I) complex ions are very large and different in different solvents and indicate some solvation effects in each solvent system

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.

Synthesis, characterization, and controlled release antibacterial behavior of antibiotic intercalated Mg–Al layered double hydroxides

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

Wang, Yi; Zhang, Dun, E-mail: zhangdun@qdio.ac.cn

Graphical abstract: The antibiotic anion released from Mg–Al LDHs provides a controlled release antibacterial activity against the growth of Micrococcus lysodeikticus in 3.5% NaCl solution. Highlights: ► Antibiotic anion intercalated LDHs were synthesized and characterized. ► The ion-exchange one is responsible for the release process. ► The diffusion through particle is the release rate limiting step. ► LDHs loaded with antibiotic anion have high antibacterial capabilities. -- Abstract: Antibiotic–inorganic clay composites including four antibiotic anions, namely, benzoate (BZ), succinate (SU), benzylpenicillin (BP), and ticarcillin (TC) anions, intercalated Mg–Al layered double hydroxides (LDHs) were synthesized via ion-exchange. Powder X-ray diffraction andmore » Fourier transform infrared spectrum analyses showed the successful intercalation of antibiotic anion into the LDH interlayer. BZ and BP anions were accommodated in the interlayer region as a bilayer, whereas SU and TC anions were intercalated in a monolayer arrangement. Kinetic simulation of the release data indicated that ion-exchange was responsible for the release process, and the diffusion through the particles was the rate-limiting step. The antibacterial capabilities of LDHs loaded with antibiotic anion toward Micrococcus lysodeikticus growth were analyzed using a turbidimetric method. Significant high inhibition rate was observed when LDH nanohybrid was introduced in 3.5% NaCl solution. Therefore, this hybrid material may be applied as nanocontainer in active antifouling coating for marine equipment.« less

In vitro biocorrosion of Ti-6Al-4V implant alloy by a mouse macrophage cell line.

PubMed

Lin, Hsin-Yi; Bumgardner, Joel D

2004-03-15

Corrosion of implant alloys releasing metal ions has the potential to cause adverse tissue reactions and implant failure. We hypothesized that macrophage cells and their released reactive chemical species (RCS) affect the alloy's corrosion properties. A custom cell culture corrosion box was used to evaluate how cell culture medium, macrophage cells and RCS altered the Ti-6Al-4V corrosion behaviors in 72 h and how corrosion products affected the cells. There was no difference in the charge transfer in the presence (75.2 +/- 17.7 mC) and absence (62.3 +/- 18.8 mC) of cells. The alloy had the lowest charge transfer (28.2 +/- 4.1 mC) and metal ion release (Ti < 10 ppb, V < 2 ppb) with activated cells (releasing RCS) compared with the other two conditions. This was attributed to an enhancement of the surface oxides by RCS. Metal ion release was very low (Ti < 20 ppb, V < 10 ppb) with nonactivated cells and did not change cell morphology, viability, and NO and ATP release compared with controls. However, IL-1beta released from the activated cells and the proliferation of nonactivated cells were greater on the alloy than the controls. In summary, macrophage cells and RCS reduced the corrosion of Ti-6Al-4V alloys as hypothesized. These data are important in understanding host tissue-material interactions. Copyright 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 717-724, 2004

A Study of Moroccan Pupils' Difficulties at Second Baccalaureate Year in Solving Chemistry Problems Relating to the Reactivity of Ethanoate Ions and to Copper-Aluminium Cells

ERIC Educational Resources Information Center

Ouasri, Ali

2017-01-01

This paper investigates the difficulties that Moroccan pupils (18-19) of the second Baccalaureate year encountered in solving chemical equilibrium problems relating to ethanoate ions' reactivity with water and methanoic acid, and to copper-aluminum cells. The pupils were asked to provide answers to questions derived from two problems. The…

Synthesis of nanoscale copper nitride thin film and modification of the surface under high electronic excitation.

PubMed

Ghosh, S; Tripathi, A; Ganesan, V; Avasthi, D K

2008-05-01

Nanoscale (approximately 90 nm) Copper nitride (Cu3N) films are deposited on borosilicate glass and Si substrates by RF sputtering technique in the reactive environment of nitrogen gas. These films are irradiated with 200 MeV Au15+ ions from Pelletron accelerator in order to modify the surface by high electronic energy deposition of heavy ions. Due to irradiation (i) at incident ion fluence of 1 x 10(12) ions/cm2 enhancement of grains, (ii) at 5 x 10912) ions/cm2 mass transport on the films surface, (iii) at 2 x 10(13) ions/cm2 line-like features on Cu3N/glass and nanometallic structures on Cu3N/Si surface are observed. The surface morphology is examined by atomic force microscope (AFM). All results are explained on the basis of a thermal spike model of ion-solid interaction.

Effect of co-existing copper and calcium on the removal of As(V) by reused aluminum oxides.

PubMed

Yang, J K; Park, Y J; Kim, K H; Lee, H Y; Min, K C; Lee, S M

2013-01-01

Among the various heavy metals, arsenic is frequently found in abandoned mine drainage and the environmental fate of arsenic in real aqueous solutions can be highly dependent on the presence of co-existing ions. In this study, removal of arsenate through adsorption on the reused aluminum oxide or through precipitation was investigated in a single and in a binary system as a function of pH and concentration. Different removal behaviors of arsenate were observed in the presence of different cations as well as a variation of the molar ratios of arsenate to cations. Co-operative effects on arsenate removal by precipitation in solution occurred with an increase of copper concentration, while a decrease of arsenate removal resulted in increasing calcium concentration. It was observed that the arsenate removal in the presence of calcium would be highly dependent on the molar ratios of both elements.

Hand-held optical sensor using denatured antibody coated electro-active polymer for ultra-trace detection of copper in blood serum and environmental samples.

PubMed

Chandra, Sutapa; Dhawangale, Arvind; Mukherji, Soumyo

2018-07-01

An optimum copper concentration in environment is highly desired for all forms of life. We have developed an ultrasensitive copper sensor which functions from femto to micro molar concentration accurately (R 2 = 0.98). The sensor is based on denatured antibody immunoglobulin G (IgG), immobilized on polyaniline (PAni) which in turn is the coating on the core of an optical fiber. The sensing relies on changes in evanescent wave absorbance in the presence of the analyte. The sensor showed excellent selectivity towards Cu (II) ions over all other metal ions. The sensor was tested with lake and marine water samples to determine unknown concentrations of copper ions and the recovery results were within 90-115%, indicating reasonable accuracy. We further integrated the fiber-optic sensor with a miniaturized hand-held instrumentation platform to develop an accurate and field deployable device which can broadly be applicable to determine Cu (II) concentration in a wide range of systems - natural water bodies, soil as well as blood serum. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthetic fluorescent probes for studying copper in biological systems

PubMed Central

Cotruvo, Joseph A.; Aron, Allegra T.; Ramos-Torres, Karla M.; Chang, Christopher J.

2015-01-01

The potent redox activity of copper is required for sustaining life. Mismanagement of its cellular pools, however, can result in oxidative stress and damage connected to aging, neurodegenerative diseases, and metabolic disorders. Therefore, copper homeostasis is tightly regulated by cells and tissues. Whereas copper and other transition metal ions are commonly thought of as static cofactors buried within protein active sites, emerging data points to the presence of additional loosely bound, labile pools that can participate in dynamic signalling pathways. Against this backdrop, we review advances in sensing labile copper pools and understanding their functions using synthetic fluorescent indicators. Following brief introductions to cellular copper homeostasis and considerations in sensor design, we survey available fluorescent copper probes and evaluate their properties in the context of their utility as effective biological screening tools. We emphasize the need for combined chemical and biological evaluation of these reagents, as well as the value of complementing probe data with other techniques for characterizing the different pools of metal ions in biological systems. This holistic approach will maximize the exciting opportunities for these and related chemical technologies in the study and discovery of novel biology of metals. PMID:25692243

Synthetic fluorescent probes for studying copper in biological systems.

PubMed

Cotruvo, Joseph A; Aron, Allegra T; Ramos-Torres, Karla M; Chang, Christopher J

2015-07-07

The potent redox activity of copper is required for sustaining life. Mismanagement of its cellular pools, however, can result in oxidative stress and damage connected to aging, neurodegenerative diseases, and metabolic disorders. Therefore, copper homeostasis is tightly regulated by cells and tissues. Whereas copper and other transition metal ions are commonly thought of as static cofactors buried within protein active sites, emerging data points to the presence of additional loosely bound, labile pools that can participate in dynamic signalling pathways. Against this backdrop, we review advances in sensing labile copper pools and understanding their functions using synthetic fluorescent indicators. Following brief introductions to cellular copper homeostasis and considerations in sensor design, we survey available fluorescent copper probes and evaluate their properties in the context of their utility as effective biological screening tools. We emphasize the need for combined chemical and biological evaluation of these reagents, as well as the value of complementing probe data with other techniques for characterizing the different pools of metal ions in biological systems. This holistic approach will maximize the exciting opportunities for these and related chemical technologies in the study and discovery of novel biology of metals.

An Investigation of Low Biofouling Copper-charged Membranes

NASA Astrophysics Data System (ADS)

Asapu, Sunitha

Water is essential for the survival of life on Earth, but pollutants in water can cause dangerous diseases and fatalities. The need for purified water has been increasing with increasing world population; however, natural sources of water such as rivers, lakes and streams, are progressively falling shorter and shorter of meeting water needs. The provision of clean, drinkable water to people is a key factor for the development of novel and alternative water purification technologies, such as membrane separations. Nanofiltration (NF) is a membrane separations technology that purifies water from lower quality sources, such as brackish water, seawater and wastewater. During the filtration of such sources, materials that are rejected by the membrane may accumulate on the surface of the membrane to foul it. Such materials include organic and inorganic matter, colloids, salts and microorganisms. The former four can often be controlled via pretreatment; however, the accumulation of microorganisms is more problematic to membranes. Biofouling is the accumulation and growth of microorganisms on the surface of membranes and on feed spacers. After attachment, microorganisms excrete extracellular polymeric substances (EPS), which form a matrix around the organism's outer surface as biofilm. These biofilms are detrimental and result in irreversible membrane fouling. Copper and silver ions inactivate the bacterial cells and prevent the DNA replication in microbial cells. Previous studies using copper-charged feed spacers have shown the ability of copper to control biofouling without a significant amount of copper leaching from copper-charged polypropylene (PP) feed spacers during crossflow filtration. Also, filtration using unmodified speed facers experienced almost 70% flux decline, while filtration using copper-charged feed spacers displayed only 25% flux decline. These intriguing results led to the hypothesis that the polymer chemistry could be extrapolated to produce membranes with increased biofouling resistance. The goal of this project was to develop low-biofouling nanofiltration cellulose acetate (CA) membranes through functionalization with metal chelating ligands charged with biocidal metal ions, i.e. copper ions. To this end, glycidyl methacrylate (GMA), an epoxy, was used to attach a chelating agent, iminodiacetic acid (IDA) to facilitate the charging of copper to the membrane surface. Both CA and CA-GMA membranes were cast using the phase-inversion method. The CA-GMA membranes were then charged with copper ions to make them low biofouling. Pore size distribution analysis of CA and copper charged membranes were conducted using various molecular weights of polyethylene glycol (PEG). CA and copper-charged membranes were characterized using Fourier Transform Infrared (FTIR), contact angle to measure hydrophilicity changes, and using scanning electron microscope (SEM) coupled with X-ray energy dispersive spectroscopy EDS to monitor copper leaching. Permeation experiments were conducted with distilled (DI) water, protein solutions, and synthetic brackish water containing microorganisms. The DI water permeation of the copper-charged membranes was initially lower than the CA membranes. The membranes were then subjected to bovine serum albumin (BSA) and lipase filtration. The copper-charged membranes showed higher pure water flux values for both proteins as compared to CA membranes. The rejection of BSA and lipase was the same for both the copper charged and CA membranes. The filtration with the synthetic brackish water showed that copper-charged membranes had higher flux values as compared to CA membranes, and biofouling analysis showed more bacteria on the CA membranes as compared to copper-charged membranes. Therefore, the copper-charged membranes made here have shown a potential to be used as low-biofouling membranes in the future.

Synthesis and Catalytic Evaluation of Dendrimer-Encapsulated Cu Nanoparticles: An Undergraduate Experiment Exploring Catalytic Nanomaterials

ERIC Educational Resources Information Center

Feng, Z. Vivian; Lyon, Jennifer L.; Croley, J. Sawyer; Crooks, Richard M.; Vanden Bout, David A.; Stevenson, Keith J.

2009-01-01

Copper nanoparticles were synthesized using generation 4 hydroxyl-terminated (G4-OH) poly(amidoamine) (PAMAM) dendrimers as templates. The synthesis is conducted by coordinating copper ions with the interior amines of the dendrimer, followed by chemical reduction to form dendrimer-encapsulated copper nanoparticles (Cu-DEN). The catalytic…

Overexpression of amyloid precursor protein increases copper content in HEK293 cells

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

Suazo, Miriam; Hodar, Christian; Morgan, Carlos

2009-05-15

Amyloid precursor protein (APP) is a transmembrane glycoprotein widely expressed in mammalian tissues and plays a central role in Alzheimer's disease. However, its physiological function remains elusive. Cu{sup 2+} binding and reduction activities have been described in the extracellular APP135-156 region, which might be relevant for cellular copper uptake and homeostasis. Here, we assessed Cu{sup 2+} reduction and {sup 64}Cu uptake in two human HEK293 cell lines overexpressing APP. Our results indicate that Cu{sup 2+} reduction increased and cells accumulated larger levels of copper, maintaining cell viability at supra-physiological levels of Cu{sup 2+} ions. Moreover, wild-type cells exposed to bothmore » Cu{sup 2+} ions and APP135-155 synthetic peptides increased copper reduction and uptake. Complementation of function studies in human APP751 transformed Fre1 defective Saccharomyces cerevisiae cells rescued low Cu{sup 2+} reductase activity and increased {sup 64}Cu uptake. We conclude that Cu{sup 2+} reduction activity of APP facilitates copper uptake and may represent an early step in cellular copper homeostasis.« less

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.

Impact of treatment on Pb release from full and partially replaced harvested Lead Service Lines (LSLs).

PubMed

Cartier, Clément; Doré, Evelyne; Laroche, Laurent; Nour, Shokoufeh; Edwards, Marc; Prévost, Michèle

2013-02-01

Release of lead from 80% partially replaced service lines was compared to full lead service lines using harvested-stabilized lead pipes and field brass connectors. After more than a year of stabilization, lead release was consistent with field samples. Over the relatively short duration partial replacement of lead pipe by copper pipe (3 months), generated high lead release, attributed to galvanic corrosion, resulting in a final outcome for lead release that was even worse than for a full lead pipe. Increased lead release was especially evident at higher flow rates. Orthophosphate reduced lead release from full lead pipes by 64%. For partially replaced samples with copper, lead concentrations were unchanged by phosphate dosing at moderate flow (103 ± 265 vs 169 ± 349 μg/L) and were increased to very high levels when sampled at high flow rates (1001 ± 1808 vs 257 ± 224 μg/L). The increase lead release was in the form of particulate lead (>90%). In comparison to the condition without treatment, increased sulfate treatment had little impact on lead release from 100%-Pb rigs but reduced lead release from partially replaced lead pipes with copper. Our results also raise questions concerning protocols based on short 30 min stagnation (as those used in Canada) due to their incapacity to consider particulate lead release generated mostly after longer stagnation. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

Migration of copper from nanocopper/LDPE composite films.

PubMed

Liu, Fang; Hu, Chang-Ying; Zhao, Quan; Shi, Yu-Jie; Zhong, Huai-Ning

2016-11-01

Three nanocopper/low-density polyethylene (LDPE) composite films were tested in food simulants (3% acetic acid and 10% ethanol) and real food matrices (rice vinegar, bottled water and Chinese liquor) to explore the behaviours of copper migration using ICP-OES and GFAAS. The effects of exposure time, temperature, nanocopper concentration and contact media on the release of copper from nanocopper/LDPE composite films were studied. It was shown that the migration of copper into 10% ethanol was much less than that into 3% acetic acid at the same conditions. With the increase of nanocopper concentration, exposure time and temperature, the release of copper increased. Copper migration does not appear to be significant in the case of bottled water and Chinese liquor compared with rice vinegar with a maximum value of 0.54 μg mL -1 for the CF-0.25# bags at 70°C for 2 h. The presence and morphology of copper nanoparticles in the films and the topographical changes of the films were confirmed by field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). In this manner, copper nanoparticles of different morphologies, sizes and distribution were found, and samples with higher nanocopper concentration had a more irregular topography. In the case of Fourier transform infrared spectroscopy (FTIR), no chemical bonds formed between copper nanoparticles and LDPE. Copper nanoparticles were just as physically dispersed in LDPE.

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

Surface Characterization on Corrosion By-products on Cu in Drinking Water Pipes

EPA Science Inventory

Copper is widely used in house-hold plumbing due to its anti-corrosion property. However, as water travels within the distribution system into corroded copper pipes, copper may be released into consumer’s tap causing major problems. In an attempt to understand the mechanism and...

Environmental concentrations of copper, chromium, and arsenic released from a chromated-copper-arsenate-(CCA-C-) treated wetland boardwalk

Treesearch

Stan T. Lebow; Daniel Foster

2005-01-01

A study was conducted to evaluate environmental accumulation and mobility of total copper, chromium, and arsenic adjacent to a chromated-copper-arsenate-(CCA-C-) treated wetland boardwalk. The study was considered a severe test because it included a large volume of treated wood in a site with high annual rainfall. Soil and sediment samples were collected before...

A New Role for Carbonic Anhydrase 2 in the Response of Fish to Copper and Osmotic Stress: Implications for Multi-Stressor Studies

PubMed Central

de Polo, Anna; Margiotta-Casaluci, Luigi; Lockyer, Anne E.; Scrimshaw, Mark D.

2014-01-01

The majority of ecotoxicological studies are performed under stable and optimal conditions, whereas in reality the complexity of the natural environment faces organisms with multiple stressors of different type and origin, which can activate pathways of response often difficult to interpret. In particular, aquatic organisms living in estuarine zones already impacted by metal contamination can be exposed to more severe salinity variations under a forecasted scenario of global change. In this context, the present study aimed to investigate the effect of copper exposure on the response of fish to osmotic stress by mimicking in laboratory conditions the salinity changes occurring in natural estuaries. We hypothesized that copper-exposed individuals are more sensitive to osmotic stresses, as copper affects their osmoregulatory system by acting on a number of osmotic effector proteins, among which the isoform two of the enzyme carbonic anhydrase (CA2) was identified as a novel factor linking the physiological responses to both copper and osmotic stress. To test this hypothesis, two in vivo studies were performed using the euryhaline fish sheepshead minnow (Cyprinodon variegatus) as test species and applying different rates of salinity transition as a controlled way of dosing osmotic stress. Measured endpoints included plasma ions concentrations and gene expression of CA2 and the α1a-subunit of the enzyme Na+/K+ ATPase. Results showed that plasma ions concentrations changed after the salinity transition, but notably the magnitude of change was greater in the copper-exposed groups, suggesting a sensitizing effect of copper on the responses to osmotic stress. Gene expression results demonstrated that CA2 is affected by copper at the transcriptional level and that this enzyme might play a role in the observed combined effects of copper and osmotic stress on ion homeostasis. PMID:25272015

Helium Ion Secondary Electron Mode Microscopy For Interconnect Material Imaging

NASA Astrophysics Data System (ADS)

Ogawa, Shinichi; Thompson, William; Stern, Lewis; Scipioni, Larry; Notte, John; Farkas, Lou; Barriss, Louise

2010-04-01

The recently developed helium ion microscope (HIM) is now capable of 0.35 nm secondary electron (SE) mode image resolution. When low-k dielectrics or copper interconnects in ultra large scale integrated circuits (ULSI) interconnect structures were imaged in this mode, it was found that unique pattern dimension and fidelity information at sub-nanometer resolution was available for the first time. This paper will discuss the helium ion microscope architecture and the SE imaging techniques that make the HIM observation method of particular value to the low-k dielectric and dual damascene copper interconnect technologies.

Removal of Mn, Fe, Ni and Cu Ions from Wastewater Using Cow Bone Charcoal

PubMed Central

Moreno, Juan Carlos; Gómez, Rigoberto; Giraldo, Liliana

2010-01-01

Cow bone charcoal (CBC) was synthesized and used for the removal of metals ions (manganese, iron, nickel and copper) from aqueous solutions. Two different adsorption models were used for analyzing the data. Adsorption capacities were determined: copper ions exhibit the greatest adsorption on cow bone charcoal because of their size and pH conditions. Adsorption capacity varies as a function of pH. Adsorption isotherms from aqueous solution of heavy metals on CBC were determined. Adsorption isotherms are consistent with Langmuir´s adsorption model. Adsorbent quantity and immersion enthalpy were studied.

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.

Results of a preimpoundment water-quality study of Swatara Creek, Pennsylvania

USGS Publications Warehouse

Fishel, David K.; Richardson, J.E.

1986-01-01

The impoundment will act as a sediment trap and thus reduce the concentrations of total phosphorus, iron, aluminum, lead, copper, and zinc immediately downstream from the impoundment. Large storm discharges and releases from the hypolimnion of the reservoir to attain the winter-pool level may contain low oxygen concentrations and elevated concentrations of iron, aluminum, lead, copper, and zinc. Unless conservation releases from the multi-level release gates are carefully controlled, low dissolved-oxygen levels and high metal concentrations may degrade the downstream water quality and be detrimental to the aquatic community.

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.

Method of fabricating a catalytic structure

DOEpatents

Rollins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

2009-09-22

A precursor to a catalytic structure comprising zinc oxide and copper oxide. The zinc oxide has a sheet-like morphology or a spherical morphology and the copper oxide comprises particles of copper oxide. The copper oxide is reduced to copper, producing the catalytic structure. The catalytic structure is fabricated by a hydrothermal process. A reaction mixture comprising a zinc salt, a copper salt, a hydroxyl ion source, and a structure-directing agent is formed. The reaction mixture is heated under confined volume conditions to produce the precursor. The copper oxide in the precursor is reduced to copper. A method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure.

Characterization of aqueous interactions of copper-doped phosphate-based glasses by vapour sorption.

PubMed

Stähli, Christoph; Shah Mohammadi, Maziar; Waters, Kristian E; Nazhat, Showan N

2014-07-01

Owing to their adjustable dissolution properties, phosphate-based glasses (PGs) are promising materials for the controlled release of bioinorganics, such as copper ions. This study describes a vapour sorption method that allowed for the investigation of the kinetics and mechanisms of aqueous interactions of PGs of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0, 1, 5 and 10mol.%). Initial characterization was performed using (31)P magic angle spinning nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared spectroscopy. Increasing CuO content resulted in chemical shifts of the predominant Q(2) NMR peak and of the (POP)as and (PO(-)) Fourier transform infrared absorptions, owing to the higher strength of the POCu bond compared to PONa. Vapour sorption and desorption were gravimetrically measured in PG powders exposed to variable relative humidity (RH). Sorption was negligible below 70% RH and increased exponentially with RH from 70 to 90%, where it exhibited a negative correlation with CuO content. Vapour sorption in 0% and 1% CuO glasses resulted in phosphate chain hydration and hydrolysis, as evidenced by protonated Q(0)(1H) and Q(1)(1H) species. Dissolution rates in deionized water showed a linear correlation (R(2)>0.99) with vapour sorption. Furthermore, cation release rates could be predicted based on dissolution rates and PG composition. The release of orthophosphate and short polyphosphate species corroborates the action of hydrolysis and was correlated with pH changes. In conclusion, the agreement between vapour sorption and routine characterization techniques in water demonstrates the potential of this method for the study of PG aqueous reactions. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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

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.

Vertically Aligned Carbon Nanotube Electrodes for Lithium-Ion Batteries

DTIC Science & Technology

2011-01-01

wpafb.af.mil (M.F. Durstock). [11] nanowires, and iron oxide/copper [12] and tin/copper [13] nanorods. Carbon nanotubes ( CNTs ) have also been examined as...negative electrodes [14–17]. Although CNTs and other nega- tive electrode nanomaterials have been shown to exhibit similar or greater capacities...rate capability [18]. Studies suggest that aligned CNTs could allow for better contact with the current collector and increased ion diffu- sivity to

Freestanding three-dimensional core–shell nanoarrays for lithium-ion battery anodes

DOE PAGES

Tan, Guoqiang; Wu, Feng; Yuan, Yifei; ...

2016-06-03

Here, structural degradation and low conductivity of transition-metal oxides lead to severe capacity fading in lithium-ion batteries. Recent efforts to solve this issue have mainly focused on using nanocomposites or hybrids by integrating nanosized metal oxides with conducting additives. Here we design specific hierarchical structures and demonstrate their use in flexible, large-area anode assemblies. Fabrication of these anodes is achieved via oxidative growth of copper oxide nanowires onto copper substrates followed by radio-frequency sputtering of carbon-nitride films, forming freestanding three-dimensional arrays with core–shell nano-architecture. Cable-like copper oxide/carbon-nitride core–shell nanostructures accommodate the volume change during lithiation-delithiation processes, the three-dimensional arrays providemore » abundant electroactive zones and electron/ion transport paths, and the monolithic sandwich-type configuration without additional binders or conductive agents improves energy/power densities of the whole electrode.« less

Freestanding three-dimensional core-shell nanoarrays for lithium-ion battery anodes.

PubMed

Tan, Guoqiang; Wu, Feng; Yuan, Yifei; Chen, Renjie; Zhao, Teng; Yao, Ying; Qian, Ji; Liu, Jianrui; Ye, Yusheng; Shahbazian-Yassar, Reza; Lu, Jun; Amine, Khalil

2016-06-03

Structural degradation and low conductivity of transition-metal oxides lead to severe capacity fading in lithium-ion batteries. Recent efforts to solve this issue have mainly focused on using nanocomposites or hybrids by integrating nanosized metal oxides with conducting additives. Here we design specific hierarchical structures and demonstrate their use in flexible, large-area anode assemblies. Fabrication of these anodes is achieved via oxidative growth of copper oxide nanowires onto copper substrates followed by radio-frequency sputtering of carbon-nitride films, forming freestanding three-dimensional arrays with core-shell nano-architecture. Cable-like copper oxide/carbon-nitride core-shell nanostructures accommodate the volume change during lithiation-delithiation processes, the three-dimensional arrays provide abundant electroactive zones and electron/ion transport paths, and the monolithic sandwich-type configuration without additional binders or conductive agents improves energy/power densities of the whole electrode.

Feed gas contaminant control in ion transport membrane systems

DOEpatents

Carolan, Michael Francis [Allentown, PA; Minford, Eric [Laurys Station, PA; Waldron, William Emil [Whitehall, PA

2009-07-07

Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

[Biosorption ability of mutants of Rhodotorula mucilaginosa UCM Y-1776].

PubMed

Mamieieva, O H; Kasatkina, T P; Lavrinchuk, V Ia

2007-01-01

Twenty stable mutants with various coloration intensity have been allocated in carotene-synthesizing natural strain Rhodotorula mucilaginosa UCM Y-1776 (wild type) after nitrosoguanidine action. Two brightly orange mutants 4L and 11 and one non-pigmented mutant 2 were chosen for the further researches. The ultraviolet was inefficient as a mutagen. Resistance to high concentration of copper ions (up to 200 mg/g), high sorption ability (Qmax = 9.1 mmol/g) was characteristic of R. mucilaginosa UCM Y-1776. Concentration of copper ions 50 mg/l was toxic for mutants 4L, 11 and 2, which sorption ability was lower in comparison with carotene pigmented R. mucilaginosa UCM Y-1776. It was shown, for the first time that there was a direct dependence between the presence of carotenoid pigments, resistance to high concentration of copper ions and sorption ability for yeast R. mucilaginosa UCM Y-1776.

Tracking metal ions through a Cu/Ag efflux pump assigns the functional roles of the periplasmic proteins

DOE PAGES

Chacon, Kelly N.; Mealman, Tiffany D.; McEvoy, Megan M.; ...

2014-10-13

Copper is an essential nutrient for all aerobic organisms but is toxic in excess. At the host–pathogen interface, macrophages respond to bacterial infection by copper-dependent killing mechanisms, whereas the invading bacteria are thought to counter with an up-regulation of copper transporters and efflux pumps. The tripartite efflux pump CusCBA and its metallochaperone CusF are vital to the detoxification of copper and silver ions in the periplasm of Escherichia coli. However, the mechanism of efflux by this complex, which requires the activation of the inner membrane pump CusA, is poorly understood. In this paper, we use selenomethionine (SeM) active site labelsmore » in a series of biological X-ray absorption studies at the selenium, copper, and silver edges to establish a “switch” role for the membrane fusion protein CusB. We determine that metal-bound CusB is required for activation of cuprous ion transfer from CusF directly to a site in the CusA antiporter, showing for the first time (to our knowledge) the in vitro activation of the Cus efflux pump. This metal-binding site of CusA is unlike that observed in the crystal structures of the CusA protein and is composed of one oxygen and two sulfur ligands. Finally, our results suggest that metal transfer occurs between CusF and apo-CusB, and that, when metal-loaded, CusB plays a role in the regulation of metal ion transfer from CusF to CusA in the periplasm.« less

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.

Tracking metal ions through a Cu/Ag efflux pump assigns the functional roles of the periplasmic proteins.

PubMed

Chacón, Kelly N; Mealman, Tiffany D; McEvoy, Megan M; Blackburn, Ninian J

2014-10-28

Copper is an essential nutrient for all aerobic organisms but is toxic in excess. At the host-pathogen interface, macrophages respond to bacterial infection by copper-dependent killing mechanisms, whereas the invading bacteria are thought to counter with an up-regulation of copper transporters and efflux pumps. The tripartite efflux pump CusCBA and its metallochaperone CusF are vital to the detoxification of copper and silver ions in the periplasm of Escherichia coli. However, the mechanism of efflux by this complex, which requires the activation of the inner membrane pump CusA, is poorly understood. Here, we use selenomethionine (SeM) active site labels in a series of biological X-ray absorption studies at the selenium, copper, and silver edges to establish a "switch" role for the membrane fusion protein CusB. We determine that metal-bound CusB is required for activation of cuprous ion transfer from CusF directly to a site in the CusA antiporter, showing for the first time (to our knowledge) the in vitro activation of the Cus efflux pump. This metal-binding site of CusA is unlike that observed in the crystal structures of the CusA protein and is composed of one oxygen and two sulfur ligands. Our results suggest that metal transfer occurs between CusF and apo-CusB, and that, when metal-loaded, CusB plays a role in the regulation of metal ion transfer from CusF to CusA in the periplasm.

Thermal annealing behavior of hydrogen and surface topography of H 2 + ion implanted tungsten

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

Zhang, Jiandong; Jiang, Weilin; Zhu, Zihua

2018-01-25

Tungsten (W) has been proposed as a plasma-facing material (PFM) in fusion reactors due to its outstanding properties. Degradation of the material properties is expected to occur as a result of hydrogen (H) isotope permeation and trapping in W. In this study, two polycrystalline W plates were implanted with 80 keV H 2 + ions to a fluence of 2E21 H+/m2 at room temperature (RT). Time-of-flight secondary ion mass spectrometry (ToF-SIMS), focused ion beam (FIB) and scanning electron microscopy (SEM) were used for sample characterization. The SIMS data shows that H atoms are distributed well beyond the ion projected range.more » Isochronal annealing appears to suggest two H release stages that might be associated with the reported activation energies. H release at RT was observed between days 10 and 70 following ion implantation, and the level was maintained over the next 60 days. In addition, FIB/SEM results exhibit H2 blister formation near the surface of the as-implanted W. The blister distribution remains unchanged after thermal annealing up to 600 °C.« less

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.

Removing adsorbed heavy metal ions from sand surfaces via applying interfacial properties of rhamnolipid.

PubMed

Haryanto, Bode; Chang, Chien-Hsiang

2015-01-01

In this study, the interfacial properties of biosurfactant rhamnolipid were investigated and were applied to remove adsorbed heavy metal ions from sand surfaces with flushing operations. The surface tension-lowering activity, micelle charge characteristic, and foaming ability of rhamnolipid were identified first. For rhamnolipid in water, the negatively charged characteristic of micelles or aggregates was confirmed and the foaming ability at concentrations higher than 40 mg/L was evaluated. By using the rhamnolipid solutions in a batch washing approach, the potential of applying the interfacial properties of rhamnolipid to remove adsorbed copper ions from sand surfaces was then demonstrated. In rhamnolipid solution flushing operations for sand-packed medium, higher efficiency was found for the removal of adsorbed copper ions with residual type than with inner-sphere interaction type, implying the important role of interaction type between the copper ion and the sand surface in the removal efficiency. In addition, the channeling effect of rhamnolipid solution flow in the sand-packed medium was clearly observed in the solution flushing operations and was responsible for the low removal efficiency with low contact areas between solution and sand. By using rhamnolipid solution with foam to flush the sand-packed medium, one could find that the channeling effect of the solution flow was reduced and became less pronounced with the increase in the rhamnolipid concentration, or with the enhanced foaming ability. With the reduced channeling effect in the flushing operations, the removal efficiency for adsorbed copper ions was significantly improved. The results suggested that the foam-enhanced rhamnolipid solution flushing operation was efficient in terms of surfactant usage and operation time.

Metal ion influence on eumelanin fluorescence and structure.

PubMed

Sutter, Jens-Uwe; Birch, David J S

2014-04-10

Melanin has long been thought to have an unworkably weak and complex fluorescence, but here we study its intrinsic fluorescence in order to demonstrate how metal ions can be used to control the rate of formation, constituents and structure of eumelanin formed from the well-known laboratory auto-oxidation of 3,4-dihydroxy-L-phenylalanine (L-DOPA). The effect on eumelanin absorption and fluorescence of a range of solvated metal ions is reported including Cu, Zn, Ni, Na and K. Monovalent cations and Zn have little effect, but the effect of transition metal cations can be considerable. For example, at pH 10, copper ions are shown to accelerate the onset of eumelanin formation, but not the rate of formation once it commences, and simplify the usual complex structure and intrinsic fluorescence of eumelanin in a way that is consistent with an increased abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). The presence of a dominant 6 ns fluorescence decay time at 480 nm, when excited at 450 nm describes a distinct photophysical species, which we tentatively assign to small oligomers. Copper is well-known to normally quench fluorescence, but increasing amounts of copper surprisingly leads to an increase in the fluorescence decay time of eumelanin, while reducing the fluorescence intensity, suggesting copper modification of the excited state. Such results have bearing on diverse areas. The most accepted morphology for melanin is that of a graphite-like sheet structure, and one which readily binds metal ions, an interaction that is thought to have an important, though as yet unclear bearing on several areas of medicine including neurology. There is also increasing interest in bio-mimicry by preparing and labelling sheet structures with metal ions for new electronic and photonic materials.

Metal ion influence on eumelanin fluorescence and structure

NASA Astrophysics Data System (ADS)

Sutter, Jens-Uwe; Birch, David J. S.

2014-06-01

Melanin has long been thought to have an unworkably weak and complex fluorescence, but here we study its intrinsic fluorescence in order to demonstrate how metal ions can be used to control the rate of formation, constituents and structure of eumelanin formed from the well-known laboratory auto-oxidation of 3,4-dihydroxy-L-phenylalanine (L-DOPA). The effect on eumelanin absorption and fluorescence of a range of solvated metal ions is reported including Cu, Zn, Ni, Na and K. Monovalent cations and Zn have little effect, but the effect of transition metal cations can be considerable. For example, at pH 10, copper ions are shown to accelerate the onset of eumelanin formation, but not the rate of formation once it commences, and simplify the usual complex structure and intrinsic fluorescence of eumelanin in a way that is consistent with an increased abundance of 5,5-dihydroxyindole-2-carboxylic acid (DHICA). The presence of a dominant 6 ns fluorescence decay time at 480 nm, when excited at 450 nm describes a distinct photophysical species, which we tentatively assign to small oligomers. Copper is well-known to normally quench fluorescence, but increasing amounts of copper surprisingly leads to an increase in the fluorescence decay time of eumelanin, while reducing the fluorescence intensity, suggesting copper modification of the excited state. Such results have bearing on diverse areas. The most accepted morphology for melanin is that of a graphite-like sheet structure, and one which readily binds metal ions, an interaction that is thought to have an important, though as yet unclear bearing on several areas of medicine including neurology. There is also increasing interest in bio-mimicry by preparing and labelling sheet structures with metal ions for new electronic and photonic materials.

Characterization of the internal ion environment of biofilms based on charge density and shape of ion.

PubMed

Kurniawan, Andi; Tsuchiya, Yuki; Eda, Shima; Morisaki, Hisao

2015-12-01

Biofilm polymers contain both electrically positively and negatively charged sites. These charged sites enable the biofilm to trap and retain ions leading to an important role of biofilm such as nutrient recycling and pollutant purification. Much work has focused on the ion-exchange capacity of biofilms, and they are known to adsorb ions through an exchange mechanism between the ions in solution and the ions adsorbed to the charged sites on the biofilm polymer. However, recent studies suggest that the adsorption/desorption behavior of ions in a biofilm cannot be explained solely by this ion exchange mechanism. To examine the possibility that a substantial amount of ions are held in the interstitial region of the biofilm polymer by an electrostatic interaction, intact biofilms formed in a natural environment were immersed in distilled water and ion desorption was investigated. All of the detected ion species were released from the biofilms over a short period of time, and very few ions were subsequently released over more time, indicating that the interstitial region of biofilm polymers is another ion reserve. The extent of ion retention in the interstitial region of biofilms for each ion can be determined largely by charge density, |Z|/r, where |Z| is the ion valence as absolute value and r is the ion radius. The higher |Z|/r value an ion has, the stronger it is retained in the interstitial region of biofilms. Ion shape is also a key determinant of ion retention. Spherical and non-spherical ions have different correlations between the condensation ratio and |Z|/r. The generality of these findings were assured by various biofilm samples. Thus, the internal regions of biofilms exchange ions dynamically with the outside environment. Copyright © 2015 Elsevier B.V. All rights reserved.

A Cell-Adhesive Plasma Polymerized Allylamine Coating Reduces the In Vivo Inflammatory Response Induced by Ti6Al4V Modified with Plasma Immersion Ion Implantation of Copper

PubMed Central

Walschus, Uwe; Hoene, Andreas; Patrzyk, Maciej; Lucke, Silke; Finke, Birgit; Polak, Martin; Lukowski, Gerold; Bader, Rainer; Zietz, Carmen; Podbielski, Andreas; Nebe, J. Barbara; Schlosser, Michael

2017-01-01

Copper (Cu) could be suitable to create anti-infective implants based on Titanium (Ti), for example by incorporating Cu into the implant surface using plasma immersion ion implantation (Cu-PIII). The cytotoxicity of Cu might be circumvented by an additional cell-adhesive plasma polymerized allylamine film (PPAAm). Thus, this study aimed to examine in vivo local inflammatory reactions for Ti6Al4V implants treated with Cu-PIII (Ti-Cu), alone or with an additional PPAAm film (Ti-Cu-PPAAm), compared to untreated implants (Ti). Successful Cu-PIII and PPAAm treatment was confirmed with X-ray Photoelectron Spectroscopy. Storage of Ti-Cu and Ti-Cu-PPAAm samples in double-distilled water for five days revealed a reduction of Cu release by PPAAm. Subsequently, Ti, Ti-Cu and Ti-Cu-PPAAm samples were simultaneously implanted into the neck musculature of 24 rats. After 7, 14 and 56 days, peri-implant tissue was retrieved from 8 rats/day for morphometric immunohistochemistry of different inflammatory cells. On day 56, Ti-Cu induced significantly stronger reactions compared to Ti (tissue macrophages, antigen-presenting cells, T lymphocytes) and to Ti-Cu-PPAAm (tissue macrophages, T lymphocytes, mast cells). The response for Ti-Cu-PPAAm was comparable with Ti. In conclusion, PPAAm reduced the inflammatory reactions caused by Cu-PIII. Combining both plasma processes could be useful to create antibacterial and tissue compatible Ti-based implants. PMID:28726761

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.

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...

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.

Use of natural clinoptilolite for the removal of lead, copper and zinc in fixed bed column.

PubMed

Stylianou, Marinos A; Hadjiconstantinou, Michalis P; Inglezakis, Vasilis J; Moustakas, Konstantinos G; Loizidou, Maria D

2007-05-08

This work deals with the removal of lead, copper and zinc from aqueous solutions by using natural zeolite (clinoptilolite). Fixed bed experiments were performed, using three different volumetric flow rates of 5, 7 and 10bed volume/h, under a total normality of 0.01N, at initial pH of 4 and ambient temperature (25 degrees C). The removal efficiency increased when decreasing the flow rate and the following selectivity series was found: Pb(2+)>Zn(2+)> or =Cu(2+). Conductivity measurements showed that lead removal follows mainly ion exchange mechanism, while copper and zinc removal follows ion exchange and sorption mechanism as well.

Microbial Copper-binding Siderophores at the Host-Pathogen Interface*

PubMed Central

Koh, Eun-Ik; Henderson, Jeffrey P.

2015-01-01

Numerous pathogenic microorganisms secrete small molecule chelators called siderophores defined by their ability to bind extracellular ferric iron, making it bioavailable to microbes. Recently, a siderophore produced by uropathogenic Escherichia coli, yersiniabactin, was found to also bind copper ions during human infections. The ability of yersiniabactin to protect E. coli from copper toxicity and redox-based phagocyte defenses distinguishes it from other E. coli siderophores. Here we compare yersiniabactin to other extracellular copper-binding molecules and review how copper-binding siderophores may confer virulence-associated gains of function during infection pathogenesis. PMID:26055720

Cascade Signal Amplification Based on Copper Nanoparticle-Reported Rolling Circle Amplification for Ultrasensitive Electrochemical Detection of the Prostate Cancer Biomarker.

PubMed

Zhu, Ye; Wang, Huijuan; Wang, Lin; Zhu, Jing; Jiang, Wei

2016-02-03

An ultrasensitive and highly selective electrochemical assay was first attempted by combining the rolling circle amplification (RCA) reaction with poly(thymine)-templated copper nanoparticles (CuNPs) for cascade signal amplification. As proof of concept, prostate specific antigen (PSA) was selected as a model target. Using a gold nanoparticle (AuNP) as a carrier, we synthesized the primer-AuNP-aptamer bioconjugate for signal amplification by increasing the primer/aptamer ratio. The specific construction of primer-AuNP-aptamer/PSA/anti-PSA sandwich structure triggered the effective RCA reaction, in which thousands of tandem poly(thymine) repeats were generated and directly served as the specific templates for the subsequent CuNP formation. The signal readout was easily achieved by dissolving the RCA product-templated CuNPs and detecting the released copper ions with differential pulse stripping voltammetry. Because of the designed cascade signal amplification strategy, the newly developed method achieved a linear range of 0.05-500 fg/mL, with a remarkable detection limit of 0.020 ± 0.001 fg/mL PSA. Finally, the feasibility of the developed method for practical application was investigated by analyzing PSA in the real clinical human serum samples. The ultrasensitivity, specificity, convenience, and capability for analyzing the clinical samples demonstrate that this method has great potential for practical disease diagnosis applications.

Modified surface based on magnetic nanocomposite of dithiooxamide/Fe3O4 as a sorbent for preconcentration and determination of trace amounts of copper

NASA Astrophysics Data System (ADS)

Mirabi, Ali; Shokuhi Rad, Ali; Khodadad, Hadiseh

2015-09-01

Magnetic nanocomposites surface (MNCS) which has anionic surfactant sodium dodecyl sulfate (SDS) coating and has undergone dithiooxamide treatment as the sorbent could be an easy and useful method to extract and make a pre-concentrated in detecting the copper ions before they are determined via the flame atomic absorption spectrometry (FAAS). The influences of the experimental parameters such as the pH of the sample, the type and concentration of the eluent, dithiooxamide concentration and volume, amount of sorbent and the interactions of ions with respect to the copper ion detection have been studied. The calibration graph was linear in the range of 2-600 ng ml-1 with detection limit of 0.2 ng ml-1. Relative standard deviation (RSD) for 6 replicate measurements was 1.8%. This method of detection has been applied to the determination of Cu ions at levels in real samples such as wheat flour, tomatoes, potatoes, red beans, oat, tap water, river water and sea water with satisfactory results.

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

Chumakov, Yu. M.; Paholnitcaia, A. Yu.; Petrenko, P. A.

Two crystal modifications of nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper (I and II) and two modifications of chloro-(2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) copper (III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordinationmore » polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated (2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper possesses antitumor activity.« less

Hydrogen bonding in basic copper salts: a spectroscopic study of malachite, Cu2(OH)2CO3, and brochantite, Cu4(OH)6SO4

NASA Astrophysics Data System (ADS)

Schmidt, M.; Lutz, H. D.

1993-05-01

Infrared and Raman spectra of the basic copper salts malachite, Cu2(OH)2CO3, and brochantite, Cu4(OH)6SO4, as well as of deuterated and 13C substituted samples are presented and discussed in terms of group theory and the hydrogen bonds present. The main results are that (i) the hydrogen donor strengths of the OH- ions are strongly increased due to the very great synergetic effect of the copper ions, (ii) the acceptor strengths of the H-bond acceptor groups (SO4 2-, CO3 2-, and OH- ions) are significantly modified by the linkage and coordination of the acceptor atoms — this complicates true assignment of the OH bands observed to the two and six different OH- ions present in malachite and brochantite, respectively -, and (iii) the Cu — O stretching modes at 430 590 cm-1 and 420 520 cm-1 for malachite and brochantite, respectively, exhibit strong, partially covalent Cu — O bonding.

Super-hard cubic BN layer formation by nitrogen ion implantation

NASA Astrophysics Data System (ADS)

Komarov, F. F.; Pilko, V. V.; Yakushev, V. A.; Tishkov, V. S.

1994-11-01

Microcrystalline and amorphous boron thin films were implanted with nitrogen ions at energies from 25 to 125 keV and with doses from 2 × 10 17 to 1 × 10 18 at.cm 2 at temperatures below 200°C. The structure of boron nitride phases after ion implantation, formation of phases and phase transformations were investigated by TEM and TED methods. The cubic boron nitride phase is revealed. The microhardness of the formed films was satisfactorily explained in terms of chemical compound formation by polyenergetic ion implantation. The influence of the copper impurity on the formation of the cubic boron nitride phase is demonstrated. It has also been shown that low concentrations of copper promote cubic BN boundary formation.

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 in relation to IUD us. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Influence of clay on the adsorption of heavy metals like copper and cadmium on chitosan.

PubMed

Prakash, Nagan; Latha, Srinivasan; Sudha, Persu N; Renganathan, N Gopalan

2013-02-01

The influence of clay on the adsorption of heavy metals like copper and cadmium on chitosan from simulated industrial wastewater is evaluated. Chitosan-clay blend with ratio of (1:1), (1:2), and (2:1) have been prepared, and these were used as membranes to remove copper and cadmium ions from synthetic industrial wastewater. The chemical parameters for quantities of adsorption of heavy metal contamination have been done, and the kinetics of adsorption has also been carried out. Clay provides enough absorbable sites to overcome mass transfer limitations. The number of absorbable sites for cadmium is more compared to copper, and thus the rate of recovery of cadmium is faster than copper, and the percentage removal of cadmium is more than copper at all times on clay over nylon 6. This difference indicates the influence of clay in the adsorption of heavy metals in comparison to synthetic polymer nylon 6. Rate constant for first-order kinetics of adsorption, k (1), for copper and cadmium is less than that of clay, which clearly indicates that clay, which is a natural polymer, is more kinetically favored compared to synthetic polymer. The difference in the intraparticle diffusion in both the natural and synthetic polymer is not much, and it suggests that the particle diffusion mechanism is the same in both cases. Copper and cadmium recovery is parallel at all times. The percentage of removal of copper increased with an increase in pH from 3 to 5. In the case of cadmium containing wastewater, the maximum removal of metal occurred at pH 5. The uptake amount of Cu(2+) ions on chitosan increased rapidly with increasing the contact time from 0 to 360 min and then reaches equilibrium after 360 min, and the equilibrium constant for copper and cadmium ions are more or less the same for the adsorption reaction. There are more adsorption sites for cadmium in the presence of clay and mass transfer limitation is avoided without resorting to rotation, which is the highlight of the present work. And more so, this is pronounced in the case of natural polymer compared to synthetic polymer.

Toxic effects of heavy metal Cu2+ on the pacific oyster Crassostrea gigas

NASA Astrophysics Data System (ADS)

Gao, Ceng; Zhang, Xinxin; Li, Xiumei; Tang, Xuexi

2017-05-01

The effects of different concentrations of heavy metal ions on the survival of the Pacific oyster Crassostrea gigas were studied by using experimental ecology method in 96 h. The results showed that the LC50 of copper ion was 21.748mg/L and the safe concentration was 2.1748mg/L mg/L. Under the condition of laboratory, under laboratory conditions, the research of Cu2+ Stress on the C. gigas gill and digestive gland and adductor muscle tissue SOD, GPx and the induction of CAT activity. The results showed that the activities of SOD, GPx and CAT in the C. gigas were significantly changed by copper ion + stress. The results showed that in the low concentration Cu2+ treatment could induce the three kinds of enzymes, in the high concentration Cu2+ treatment group, SOD and CAT and GPx on the inhibition of the effect. The sensitivity of the three antioxidant enzymes to copper ion showed a certain difference. The sensitivity of the three kinds of tissue enzymes to Cu2+ treatment was digestive gland> fascia> gill. The experimental results show that the single factor for copper in water pollutants, the C. gigas digestive gland tissue SOD, GPX and CAT activity has certain significance to it, but will it as index applied to the actual water need further study.

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.

Effect of surface passivation on corrosion resistance and antibacterial properties of Cu-bearing 316L stainless steel

NASA Astrophysics Data System (ADS)

Zhao, Jinlong; Xu, Dake; Shahzad, M. Babar; Kang, Qiang; Sun, Ying; Sun, Ziqing; Zhang, Shuyuan; Ren, Ling; Yang, Chunguang; Yang, Ke

2016-11-01

The resistance for pitting corrosion, passive film stability and antibacterial performance of 316L-Cu SS passivated by nitric acid solution containing certain concentration of copper sulfate, were studied by electrochemical cyclic polarization, electrochemical impedance spectroscopy (EIS) and co-culture with bacteria. Inductively coupled plasma mass spectrometry (ICP-MS) was used to analyze the Cu2+ ions release from 316L-Cu SS surface. XPS analysis proved that the enrichment of CuO, Cr2O3 and Cr(OH)3 on the surface of specimen could simultaneously guarantee a better corrosion resistance and stable antibacterial properties. The biocompatibility evaluation determined by RTCA assay also indicated that the 316L-Cu SS after antibacterial passivation was completely biocompatible.

Toxicity of silver and copper to Cucurbita pepo: differential effects of nano and bulk-size particles.

PubMed

Musante, Craig; White, Jason C

2012-09-01

The phytotoxicity of bulk and nanoparticle Cu and Ag was directly compared. NP Ag reduced biomass and transpiration by 66-84% when compared with bulk Ag. The Ag ion concentration was 4.4-10-times greater in NP than bulk particle solutions. The Cu ion concentration was 1.4-4.4-times greater in bulk than NP amended solutions. Humic acid (50 mg/L) decreased the ion content of bulk Cu solution by 38-42% but increased ion Cu content of NP solutions by 1.4-2.9 times. Bulk and NP Cu were highly phytotoxic; growth and transpiration were reduced by 60-70% relative to untreated controls. NP Cu phytotoxicity was unaffected by solution type, but humic acid (50 mg/L) completely alleviated phytotoxicity caused by bulk Cu. The data demonstrate differential toxicity of Ag NP relative to bulk Ag. The finding that humic acid and solution chemistry differentially impact bulk and NP behavior highlights the importance of evaluating nanoparticles under environmentally relevant conditions. Copyright © 2010 Wiley Periodicals, Inc.

Surface modification of malachite with ethanediamine and its effect on sulfidization flotation

NASA Astrophysics Data System (ADS)

Feng, Qicheng; Zhao, Wenjuan; Wen, Shuming

2018-04-01

Ethanediamine was used to modify the mineral surface of malachite to improve its sulfidization and flotation behavior. The activation mechanism was investigated by adsorption experiments, X-ray photoelectron spectroscopy (XPS) analysis, and zeta potential measurements. Microflotation experiments showed that the flotation recovery of malachite was enhanced after the pretreatment of the mineral particles with ethanediamine prior to the addition of Na2S. Adsorption tests revealed that numerous sulfide ion species in the pulp solution were transferred onto the mineral surface through the formation of more copper sulfide species. This finding was confirmed by the results of the XPS measurements. Ethanediamine modification not only increased the contents of copper sulfide species on the malachite surface but also enhanced the reactivity of the sulfidization products. During sulfidization, Cu(II) species on the mineral surface were reduced into Cu(I) species, and the percentages of S22- and Sn2- relative to the total S increased after modification, resulting in increased surface hydrophobicity. The results of zeta potential measurements showed that the ethanediamine-modified mineral surface adsorbed with more sulfide ion species was advantageous to the attachment of xanthate species, thereby improving malachite floatability. The proposed ethanediamine modification followed by sulfidization xanthate flotation exhibits potential for industrial application.

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.

Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

PubMed

Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

2008-02-28

The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

Structural and magnetic characterization of a tetranuclear copper(II) cubane stabilized by intramolecular metal cation-π interactions.

PubMed

Papadakis, Raffaello; Rivière, Eric; Giorgi, Michel; Jamet, Hélène; Rousselot-Pailley, Pierre; Réglier, Marius; Simaan, A Jalila; Tron, Thierry

2013-05-20

A novel tetranuclear copper(II) complex (1) was synthesized from the self-assembly of copper(II) perchlorate and the ligand N-benzyl-1-(2-pyridyl)methaneimine (L(1)). Single-crystal X-ray diffraction studies revealed that complex 1 consists of a Cu4(OH)4 cubane core, where the four copper(II) centers are linked by μ3-hydroxo bridges. Each copper(II) ion is in a distorted square-pyramidal geometry. X-ray analysis also evidenced an unusual metal cation-π interaction between the copper ions and phenyl substituents of the ligand. Calculations based on the density functional theory method were used to quantify the strength of this metal-π interaction, which appears as an important stabilizing parameter of the cubane core, possibly acting as a driving parameter in the self-aggregation process. In contrast, using the ligand N-phenethyl-1-(2-pyridyl)methaneimine (L(2)), which only differs from L(1) by one methylene group, the same synthetic procedure led to a binuclear bis(μ-hydroxo)copper(II) complex (2) displaying intermolecular π-π interactions or, by a slight variation of the experimental conditions, to a mononuclear complex (3). These complexes were studied by X-ray diffraction techniques. The magnetic properties of complexes 1 and 2 are reported and discussed.

A thiourea derivative as potential ionophore for copper sensing

NASA Astrophysics Data System (ADS)

Ying, Kook Shih; Heng, Lee Yook; Hassan, Nurul Izzaty; Hasbullah, Siti Aishah

2018-04-01

A new thiourea derivative, N1,N3-bis[[3,5-bis(trifluoromethyl)phenyl]carbamothioyl]isophthalamide (TPC), as a potential copper ionophore was investigated. TPC was immobilized via drop casting method into poly(n-butyl acrylate) pBA membrane and the sensor was characterized by potentiometric method. The sensor fabricated based on TPC showed a Nernstian response towards copper ion with the slope of 27.07±2.84 mV/decade in the range of 1.0×10-6 - 1.0-10-4 M and limit of detection of 6.24 × 10-7 M. In addition, based on the separate solution method (SSM), the logarithm selectivity coefficients were less than -3.00 for monovalent, divalent and trivalent cations that are present in the environmental water samples such as K+, Ca2+, Mg2+ and Fe3+. This confirmed that the sensor fabricated with TPC exhibited good sensitivity and selectivity towards copper ion.

Co-occurring increases of calcium and organellar reactive oxygen species determine differential activation of antioxidant and defense enzymes in Ulva compressa (Chlorophyta) exposed to copper excess.

PubMed

Gonzalez, Alberto; Vera, Jeannette; Castro, Jorge; Dennett, Geraldine; Mellado, Macarena; Morales, Bernardo; Correa, Juan A; Moenne, Alejandra

2010-10-01

In order to analyse copper-induced calcium release and (reactive oxygen species) ROS accumulation and their role in antioxidant and defense enzymes activation, the marine alga Ulva compressa was exposed to 10 µM copper for 7 d. The level of calcium, extracellular hydrogen peroxide (eHP), intracellular hydrogen peroxide (iHP) and superoxide anions (SA) as well as the activities of ascorbate peroxidase (AP), glutathione reductase (GR), glutathione-S-transferase (GST), phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were determined. Calcium release showed a triphasic pattern with peaks at 2, 3 and 12 h. The second peak was coincident with increases in eHP and iHP and the third peak with the second increase of iHP. A delayed wave of SA occurred after day 3 and was not accompanied by calcium release. The accumulation of iHP and SA was mainly inhibited by organellar electron transport chains inhibitors (OETCI), whereas calcium release was inhibited by ryanodine. AP activation ceased almost completely after the use of OETCI. On the other hand, GR and GST activities were partially inhibited, whereas defense enzymes were not inhibited. In contrast, PAL and LOX were inhibited by ryanodine, whereas AP was not inhibited. Thus, copper stress induces calcium release and organellar ROS accumulation that determine the differential activation of antioxidant and defense enzymes. © 2010 Blackwell Publishing Ltd.

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 the friction was found to increase with sliding velocity and was strongly influenced by material transfer from the copper to the steel pin. An increase in the coefficient of friction with sliding velocity was observed for the sliding of OFHC copper against Nitronic 40 steel in RBGG tests. The increase in the coefficient of friction was correlated to an increase in subsurface plastic deformation and grain refinement. The growth of the nanocrystalline tribolayer in copper after sliding against 440C stainless steel at varying times was studied at sliding velocities of 0.05 and 1.0 m/s. A sliding velocity of 0.05 m/s produced a consistent nanocrystalline layer in as little as 10 s. The thickness of the nanocrystalline layer grew to an average thickness of 3 microm after 10 ks of sliding, but large variations in thickness were observed. A sliding velocity of 1.0 m/s produced a continuous nanocrystalline layer after 10 s of sliding. Ledges developed on the wear tracks at longer sliding times which greatly influenced the tribolayer thickness making it difficult to quantify. Dynamic recrystallization of the tribolayer also led to difficulties in measuring its thickness.

Leaching for recovery of copper from municipal solid waste incineration fly ash: influence of ash properties and metal speciation.

PubMed

Lassesson, Henric; Fedje, Karin Karlfeldt; Steenari, Britt-Marie

2014-08-01

Recovery of metals occurring in significant amounts in municipal solid waste incineration fly ash, such as copper, could offer several advantages: a decreased amount of potentially mobile metal compounds going to landfill, saving of natural resources and a monetary value. A combination of leaching and solvent extraction may constitute a feasible recovery path for metals from municipal solid waste incineration fly ash. However, it has been shown that the initial dissolution and leaching is a limiting step in such a recovery process. The work described in this article was focused on elucidating physical and chemical differences between two ash samples with the aim of explaining the differences in copper release from these samples in two leaching methods. The results showed that the chemical speciation is an important factor affecting the release of copper. The occurrence of copper as phosphate or silicate will hinder leaching, while sulphate and chloride will facilitate leaching. © The Author(s) 2014.

Impact of substituents and nonplanarity on nickel and copper porphyrin electrochemistry: first observation of a Cu(II)/Cu(III) reaction in nonaqueous media.

PubMed

Fang, Yuanyuan; Senge, Mathias O; Van Caemelbecke, Eric; Smith, Kevin M; Medforth, Craig J; Zhang, Min; Kadish, Karl M

2014-10-06

Electrochemical studies of the oxidation of dodecasubstituted and highly nonplanar nickel porphyrins in a noncoordinating solvent have previously revealed the first nickel(III) porphyrin dication. Herein, we investigate if these nonplanar porphyrins can also be used to detect the so far unobserved copper(III) porphyrin dication. Electrochemical studies of the oxidation of (DPP)Cu and (OETPP)Cu show three processes, the first two of which are macrocycle-centered to give the porphyrin dication followed by a Cu(II)/Cu(III) process at more positive potential. Support for the assignment of the Cu(II)/Cu(III) process comes from the linear relationships observed between E1/2 and the third ionization potential of the central metal ions for iron, cobalt, nickel, and copper complexes of (DPP)M and (OETPP)M. In addition, the oxidation behavior of additional nonplanar nickel porphyrins is investigated in a noncoordinating solvent, with nickel meso-tetraalkylporphyrins also being found to form nickel(III) porphyrin dications. Finally, examination of the nickel meso-tetraalkylporphyrins in a coordinating solvent (pyridine) reveals that the first oxidation becomes metal-centered under these conditions, as was previously noted for a range of nominally planar porphyrins.

Impact of copper substitution on the structural, ferroelectric and magnetic properties of tungsten bronze ceramics

NASA Astrophysics Data System (ADS)

Jindal, Shilpi; Devi, Sheela; Batoo, Khalid Mujasam; Kumar, Gagan; Vasishth, Ajay

2018-05-01

The copper substituted tungsten bronze ceramics with generic formula Ba5CaCuXTi2-xNb8O30(x = 0.0, 0.02, 0.04, 0.06 and 0.08) were successfully synthesized for the first time by solid state reaction method. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) were utilized to examine the different structural parameters and elemental compositions. XRD study depicted the single phase tetragonal structure having space group P4bm. The crystallite size was observed to be in the range 14.4-30.23 nm. The coexistent of ferroelectricity and magnetism was established by P-E and M-H measurements. The P-E loop study indicated an increase in the coercive field (11.805-23.736 kVcm-1) while the M-H study depicted adecrease in the magnetization (7.65 × 10-4-5.32 × 10-4 emu/g) with the incorporation of Cu2+ ions. Raman spectrum depicted that there is shift in the position of Raman modes with the substitution of copper which revealed one-mode behavior in the synthesized ceramics.

Corrosion of dental magnet attachments for removable prostheses on teeth and implants.

PubMed

Boeckler, Arne F; Ehring, Carolin; Morton, Dean; Geis-Gerstorfer, Jürgen; Setz, Juergen M

2009-06-01

For a long time, the use of magnets for the anchorage of dental prostheses failed due to lack of biocompatibility and the magnets' high susceptibility to corrosion in the mouth. These facts make encapsulation of the magnetic alloy with a corrosion-resistant, tight, and functionally firm sealing necessary. Due to different products and analysis methods, it is not feasible to compare the findings for contemporary products with the sparse and rather old test results in the literature. Therefore, the aim of this study was the standardized control and the comparison of the corrosion behavior of modern magnetic attachments for use on teeth and dental implants. Thirty-seven components of magnetic attachments on implants and natural teeth from different alloys (NdFeB, SmCo, Ti, CrMoMnTiFe, etc.) as delivered by the manufacturers or fabricated according to their instructions were examined for their corrosion behavior using the statical immersion analysis (ISO 10271:2001). Four specimens of every product with the same design were used. An uncased SmCo magnet served as control. Analyses after 1, 4, 7, and 28 days of the storage in corrosion solution were made. The eluate was examined quantitatively on the alloy components of the respective component with the help of optical emission spectrometry (microg/cm(2)). The results were compared to the requirements of ISO standard 22674:2006. In addition, existing corrosion products were also defined in the solution after 28 days. The results were analyzed descriptively and statistically to determine possible significant differences (t-test and Mann-Whitney-Wilcoxon rank-sums test; p < 0.05). Dissolved metal ions could be found on all tested products. The release after 1 and 4 days was different for all specimens. In the group of implant abutments, the highest ion release after 7 days was found (all measurements microg/cm(2)): Fe (13.94, Magfit-IP-IDN dome type), Pd (1.53, Medical-anchor), Cr (1.32, Magfit-IP-IDN dome type), Ti (1.09, Magfit-IP-IDN abutment), Co (0.81, Medical-anchor), and B (0.6, Magfit-IP-IDN dome type). After 28 days, the analyzed ion release increased irregularly: Fe (173.58, Magfit-IP-IDN dome type), Pd (44.17, Medical-anchor), Cr (2.02, Magfit-IP-IDN dome type), Ti (2.11, Magfit-IP-IDN abutment), Co (26.13, Medical-anchor), B (1.77, Magfit-IP-IDN dome type), and Nd (79.18, Magfit-IP-IDN dome type). In the group of magnetic systems on natural teeth, the highest ion release after 7 days was found for Fe (4.81, Magfit DX 800 keeper), Cr (1.18, Magfit DX 800 keeper), Pd (0.21, Direct System Keeper), Ni (0.18, WR-Magnet S3 small), Co (0.12, Direct System Keeper), and Ti (0.09, Magna Cap - Mini). After 28 days, the analyzed ion release increased non-uniformly: Fe (31.92, Magfit DX 800 Keeper), Cr (6.65, Magfit DX 800 Keeper), Pd (18.19, Direct System Keeper), Ni (0.61, WR-Magnet S3 small), Co (10.94, Direct System Keeper), Ti (0.83, Magna Cap - Mini), and Pd (2.78, EFM Alloy). In contrast, the uncased control magnet showed an exponential release after 7 days of Sm ions (55.06) and Co-ions (86.83), after 28 days of Sm ions (603.91) and Co ions (950.56). The release of corrosion products of all tested products stayed significantly under the limit of 200 microg/cm(2) (ISO 22674:2006). In contrast, the non-encapsulated control magnet exceeded that limit significantly. The analysis of the corrosion behavior of modern magnetic attachments for use on teeth and dental implants according to ISO 10271:2001 showed that metal ions had dissolved on all specimens. In the case of one product, the magnet corroded. For this product, an improvement of the capsulation would be desirable. None of the products reached the limit specified in ISO 22674:2006. All products seem to be suitable for dental application. Further studies in regard to the specific biocompatibility and possible cytotoxic effects on mucosa and tissue would be desirable.

Formulation and Evaluation of Antibacterial Creams and Gels Containing Metal Ions for Topical Application

PubMed Central

Chen, Mei X.; Alexander, Kenneth S.

2016-01-01

Background. Skin infections occur commonly and often present therapeutic challenges to practitioners due to the growing concerns regarding multidrug-resistant bacterial, viral, and fungal strains. The antimicrobial properties of zinc sulfate and copper sulfate are well known and have been investigated for many years. However, the synergistic activity between these two metal ions as antimicrobial ingredients has not been evaluated in topical formulations. Objective. The aims of the present study were to (1) formulate topical creams and gels containing zinc and copper alone or in combination and (2) evaluate the in vitro antibacterial activity of these metal ions in the formulations. Method. Formulation of the gels and creams was followed by evaluating their organoleptic characteristics, physicochemical properties, and in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus. Results. Zinc sulfate and copper sulfate had a strong synergistic antibacterial activity in the creams and gels. The minimum effective concentration was found to be 3 w/w% for both active ingredients against the two tested microorganisms. Conclusions. This study evaluated and confirmed the synergistic in vitro antibacterial effect of copper sulfate and zinc sulfate in a cream and two gels. PMID:27885352

A closed loop process for recycling spent lithium ion batteries

NASA Astrophysics Data System (ADS)

Gratz, Eric; Sa, Qina; Apelian, Diran; Wang, Yan

2014-09-01

As lithium ion (Li-ion) batteries continue to increase their market share, recycling Li-ion batteries will become mandatory due to limited resources. We have previously demonstrated a new low temperature methodology to separate and synthesize cathode materials from mixed cathode materials. In this study we take used Li-ion batteries from a recycling source and recover active cathode materials, copper, steel, etc. To accomplish this the batteries are shredded and processed to separate the steel, copper and cathode materials; the cathode materials are then leached into solution; the concentrations of nickel, manganese and cobalt ions are adjusted so NixMnyCoz(OH)2 is precipitated. The precipitated product can then be reacted with lithium carbonate to form LiNixMnyCozO2. The results show that the developed recycling process is practical with high recovery efficiencies (∼90%), and 1 ton of Li-ion batteries has the potential to generate 5013 profit margin based on materials balance.

Microporous spongy chitosan monoliths doped with graphene oxide as highly effective adsorbent for methyl orange and copper nitrate (Cu(NO3)2) ions.

PubMed

Wang, Ying; Liu, Xu; Wang, Hongfang; Xia, Guangmei; Huang, Wei; Song, Rui

2014-02-15

In the current study, microporous spongy chitosan monoliths doped with small amount of graphene oxide (CSGO monoliths) with high porosity (96-98%), extraordinary high water absorption (more than 2000%) and low density (0.0436-0.0607 g cm(-3)) were prepared by the freeze-drying method and used as adsorbents for anionic dyes methyl orange (MO) and Cu(2+) ions. The adsorption behavior of the CSGO monoliths and influencing factors such as pH value, graphene oxide (GO) content, concentration of pollutants as well as adsorption kinetics were studied. Specifically, the saturated adsorption capacity for MO is 567.07 mg g(-1), the highest comparing with other publication results, and it is 53.69 mg g(-1) for Cu(2+) ions. Since they are biodegradable, non-toxic, efficient, low-cost and easy to prepare, we believe that these microporous spongy CSGO monoliths will be the promising candidates for water purification. Copyright © 2013 Elsevier Inc. All rights reserved.

Selective time-resolved binding of copper(II) by pyropheophorbide-a methyl ester.

PubMed

Ghosh, Indrajit; Saleh, Na'il; Nau, Werner M

2010-05-01

The complexation behavior of pyropheophorbide-a methyl ester (PPME) with transition metal ions as well as other biologically relevant metal ions has been investigated in water-DMF (2 : 1 v/v) solution. PPME was found to selectively complex Cu(2+) ions, which leads to a distinct change in its absorption spectrum as well as efficient fluorescence quenching. The degree of fluorescence quenching by Cu(2+) depended on concentration and time. Upon addition of Cu(2+), the fluorescence showed a time-resolved decay on the time scale of minutes to hours, with the decay rate being dependent on the cation concentration. Fitting according to a bimolecular reaction rate law provided a rate constant of 650 +/- 90 M(-1) s(-1) at 298 K for metallochlorin formation. The potential implications of Cu(2+) binding for the use of PPME in photodynamic therapy are discussed, along with its use as a fluorescent sensor for detection of micromolar concentrations of Cu(2+).

Ca2+ Overload and Sarcoplasmic Reticulum Instability in tric-a Null Skeletal Muscle*

PubMed Central

Zhao, Xiaoli; Yamazaki, Daiju; Park, Ki Ho; Komazaki, Shinji; Tjondrokoesoemo, Andoria; Nishi, Miyuki; Lin, Peihui; Hirata, Yutaka; Brotto, Marco; Takeshima, Hiroshi; Ma, Jianjie

2010-01-01

The sarcoplasmic reticulum (SR) of skeletal muscle contains K+, Cl−, and H+ channels may facilitate charge neutralization during Ca2+ release. Our recent studies have identified trimeric intracellular cation (TRIC) channels on SR as an essential counter-ion permeability pathway associated with rapid Ca2+ release from intracellular stores. Skeletal muscle contains TRIC-A and TRIC-B isoforms as predominant and minor components, respectively. Here we test the physiological function of TRIC-A in skeletal muscle. Biochemical assay revealed abundant expression of TRIC-A relative to the skeletal muscle ryanodine receptor with a molar ratio of TRIC-A/ryanodine receptor ∼5:1. Electron microscopy with the tric-a−/− skeletal muscle showed Ca2+ overload inside the SR with frequent formation of Ca2+ deposits compared with the wild type muscle. This elevated SR Ca2+ pool in the tric-a−/− muscle could be released by caffeine, whereas the elemental Ca2+ release events, e.g. osmotic stress-induced Ca2+ spark activities, were significantly reduced likely reflecting compromised counter-ion movement across the SR. Ex vivo physiological test identified the appearance of “alternan” behavior with isolated tric-a−/− skeletal muscle, i.e. transient and drastic increase in contractile force appeared within the decreasing force profile during repetitive fatigue stimulation. Inhibition of SR/endoplasmic reticulum Ca2+ ATPase function could lead to aggravation of the stress-induced alternans in the tric-a−/− muscle. Our data suggests that absence of TRIC-A may lead to Ca2+ overload in SR, which in combination with the reduced counter-ion movement may lead to instability of Ca2+ movement across the SR membrane. The observed alternan behavior with the tric-a−/− muscle may reflect a skeletal muscle version of store overload-induced Ca2+ release that has been reported in the cardiac muscle under stress conditions. PMID:20858894

Surface Induced Dissociation Coupled with High Resolution Mass Spectrometry Unveils Heterogeneity of a 211 kDa Multicopper Oxidase Protein Complex

NASA Astrophysics Data System (ADS)

Zhou, Mowei; Yan, Jing; Romano, Christine A.; Tebo, Bradley M.; Wysocki, Vicki H.; Paša-Tolić, Ljiljana

2018-01-01

Manganese oxidation is an important biogeochemical process that is largely regulated by bacteria through enzymatic reactions. However, the detailed mechanism is poorly understood due to challenges in isolating and characterizing these unknown enzymes. A manganese oxidase, Mnx, from Bacillus sp. PL-12 has been successfully overexpressed in active form as a protein complex with a molecular mass of 211 kDa. We have recently used surface induced dissociation (SID) and ion mobility-mass spectrometry (IM-MS) to release and detect folded subcomplexes for determining subunit connectivity and quaternary structure. The data from the native mass spectrometry experiments led to a plausible structural model of this multicopper oxidase, which has been difficult to study by conventional structural biology methods. It was also revealed that each Mnx subunit binds a variable number of copper ions. Becasue of the heterogeneity of the protein and limited mass resolution, ambiguities in assigning some of the observed peaks remained as a barrier to fully understanding the role of metals and potential unknown ligands in Mnx. In this study, we performed SID in a modified Fourier transform-ion cyclotron resonance (FTICR) mass spectrometer. The high mass accuracy and resolution offered by FTICR unveiled unexpected artificial modifications on the protein that had been previously thought to be iron bound species based on lower resolution spectra. Additionally, isotopically resolved spectra of the released subcomplexes revealed the metal binding stoichiometry at different structural levels. This method holds great potential for in-depth characterization of metalloproteins and protein-ligand complexes. [Figure not available: see fulltext.

Comparison of elastic properties of nickel-titanium orthodontic archwires.

PubMed

Sarul, Michał; Kowala, Beata; Antoszewska, Joanna

2013-01-01

Cognizance of the mechanical properties of nickel-titanium archwires is necessary for the management of orthodontic therapy with fixed appliances. Acting on the periodontium with forces that are too heavy may lead to such complications as: pain, tooth root resorption and destruction of the alveolar bone and may also lead to retardation in tooth movement. The aim of the study was to assess the activation and deactivation forces of nickel-titanium archwires: Titanol Superelastic, Copper NiTi 35oC and NeoSentalloy. The examined material was 90 samples of Titanol Superelastic, Copper NiTi 35oC and NeoSentalloy with diameters of 0.016 and 0.016 x 0.022. All tests were carried out on the Zwick mechanical tests machine at a temperature of 30o C. In the group of archwires with diameters 0.016, the levels of deactivation forces were, respectively, from highest to lowest: Titanol Supertelastic, NeoSentalloy, Copper NiTi 35oC. In the group of rectangular archwires 0.016 x 0.022, the highest deactivation forces were released in Titanol Superelastic. With the high levels of deflection, 0.016 x 0.022 NeoSentalloy archwires released statistically significantly higher levels of force than 0.016 x 0.022 Copper NiTi 35o C, but this force diminished rapidly with lower deflection and below 3 mm of deflection, the highest forces were released by Copper NiTi 35o C. Testing the mechanical properties of the nickel-titanium wires of various diameters, it was found that round section wires release forces which fall within the range of optimal forces.

Aging of Dissolved Copper and Copper-based Nanoparticles in Five Different Soils: Short-term Kinetics vs. Long-term Fate

EPA Science Inventory

With the growing availability and use of copper-based nanomaterials (Cu-NMs), there is increasing concern regarding their release and potential impact on the environment. In this study, the short term (≤5 d) aging profile and the long-term (135 d) speciation of dissolved Cu, cop...

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The sample cell at the heart of CVX-2 will sit inside a thermostat providing three layers of insulation. The cell itself comprises a copper body that conducts heat efficiently and smoothes out thermal variations that that would destroy the xenon's uniformity. Inside the cell, the oscillating screen viscometer element is supported between two pairs of electrodes that deflect the screen and then measure screen motion.

Microgravity

NASA Image and Video Library

2001-01-24

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The sample cell at the heart of CVX-2 will sit inside a thermostat providing three layers of insulation. The cell itself comprises a copper body that conducts heat efficiently and smoothes out thermal variations that that would destroy the xenon's uniformity. Inside the cell, the oscillating screen viscometer element is supported between two pairs of electrodes that deflect the screen and then measure screen motion.

Ion Beam Processing.

DTIC Science & Technology

1987-03-13

guides Taps for plastics Orthopedic implants (hip and knee joints, etc.) Extrusion spinnerettes Finishing rolls for copper rod Extrusion nozzles...detail in following sections. C. Comparison to Coating Techniques -,* Because ion implantation is a process that modifies surface properties it is often...Therefore, it is important to understand the differences between ion implantation and coating techniques, especially ion plating. The result of ion

Metamagnetism in hydrophobically induced carboxylate (phenylmalonate)-bridged copper(II) layers.

PubMed

Pasán, Jorge; Sanchiz, Joaquín; Ruiz-Pérez, Catalina; Campo, Javier; Lloret, Francesc; Julve, Miguel

2006-07-21

Self-assembly of copper(l) ions, phenylmalonate and pyrimidine yields the layered compound [Cu(pym)(Phmal)n (1) where intralayer ferro- and interlayer antiferromagnetic interactions occur with three-dimensional antiferromagnetic ordering at T(c) = 2.15 K.