Статті в журналах з теми "Metal ion import"
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1
Neville, Stephanie L., Jennie Sjöhamn, Jacinta A. Watts, Hugo MacDermott-Opeskin, Stephen J. Fairweather, Katherine Ganio, Alex Carey Hulyer, et al. "The structural basis of bacterial manganese import." Science Advances 7, no. 32 (August 2021): eabg3980. http://dx.doi.org/10.1126/sciadv.abg3980.
Повний текст джерелаАнотація:
Metal ions are essential for all forms of life. In prokaryotes, ATP-binding cassette (ABC) permeases serve as the primary import pathway for many micronutrients including the first-row transition metal manganese. However, the structural features of ionic metal transporting ABC permeases have remained undefined. Here, we present the crystal structure of the manganese transporter PsaBC from Streptococcus pneumoniae in an open-inward conformation. The type II transporter has a tightly closed transmembrane channel due to “extracellular gating” residues that prevent water permeation or ion reflux. Below these residues, the channel contains a hitherto unreported metal coordination site, which is essential for manganese translocation. Mutagenesis of the extracellular gate perturbs manganese uptake, while coordination site mutagenesis abolishes import. These structural features are highly conserved in metal-specific ABC transporters and are represented throughout the kingdoms of life. Collectively, our results define the structure of PsaBC and reveal the features required for divalent cation transport.
2
F. M. Cellier, Mathieu. "Evolutionary analysis of Slc11 mechanism of proton-coupled metal-ion transmembrane import." AIMS Biophysics 3, no. 2 (2016): 286–318. http://dx.doi.org/10.3934/biophy.2016.2.286.
Повний текст джерела
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Camponeschi, Francesca, and Lucia Banci. "Metal cofactors trafficking and assembly in the cell: a molecular view." Pure and Applied Chemistry 91, no. 2 (February 25, 2019): 231–45. http://dx.doi.org/10.1515/pac-2018-0720.
Повний текст джерелаАнотація:
Abstract Metal ions are essential cofactors required by the proteome of organisms from any kingdom of life to correctly exert their functions. Dedicated cellular import, transport and homeostasis systems assure that the needed metal ion is correctly delivered and inserted into the target proteins and avoid the presence of free metal ions in the cell, preventing oxidative damaging. Among metal ions, in eukaryotic organisms copper and iron are required by proteins involved in absolutely essential functions, such as respiration, oxidative stress protection, catalysis, gene expression regulation. Copper and iron binding proteins are localized in essentially all cellular compartments. Copper is physiologically present mainly as individual metal ion. Iron can be present both as individual metal ion or as part of cofactors, such as hemes and iron-sulfur (Fe-S) clusters. Both metal ions are characterized by the ability to cycle between different oxidation states, which enable them to catalyze redox reactions and to participate in electron transfer processes. Here we describe in detail the main processes responsible for the trafficking of copper and iron sulfur clusters, with particular interest for the structural aspects of the maturation of copper and iron-sulfur-binding proteins.
4
Jakubovics, Nicholas S. "An ion for an iron: streptococcal metal homeostasis under oxidative stress." Biochemical Journal 476, no. 4 (February 28, 2019): 699–703. http://dx.doi.org/10.1042/bcj20190017.
Повний текст джерелаАнотація:
Abstract The ability of opportunistic pathogens such as Group A Streptococcus (GAS) to transition between mucosal colonisation and invasive disease requires complex systems for adapting to markedly different host environments. The battle to acquire essential trace metals such as manganese and iron from the host is central to pathogenesis. Using a molecular genetic approach, Turner et al. [Biochem. J. (2019) 476, 595–611] show that it is not just individual metal concentrations that are important, but the ratio of iron to manganese within cells. Increasing this ratio by knocking out pmtA, encoding the Fe(II) exporter PmtA, or by disrupting mtsA, encoding an MtsABC Mn(II)-import system component, led to reductions in superoxide dismutase (SodA) activity and increased sensitivity to oxidative stress. The authors show that SodA is at least 4-fold more active with Mn bound than with Fe and speculate that high intracellular Fe:Mn ratios reduce superoxide dismutase activity through the mismetalation of SodA. Challenging wild-type GAS with 1 mM H2O2 led to a decrease in Fe:Mn ratio and a 3-fold increase in SodA activity, indicating that modulation of the balance between intracellular Fe and Mn may play an important role in adaptation to oxidative stress. This work unravels some of the key mechanisms for maintaining appropriate Mn and Fe concentrations within bacterial cells and underscores the need for future studies that take an holistic view to metal ion homeostasis in bacteria. Strategies aimed at interfering with the balance of intracellular metal ions represent a promising approach for the control of invasive microbial infections.
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Chi, N. C., E. J. Adam, and S. A. Adam. "Sequence and characterization of cytoplasmic nuclear protein import factor p97." Journal of Cell Biology 130, no. 2 (July 15, 1995): 265–74. http://dx.doi.org/10.1083/jcb.130.2.265.
Повний текст джерелаАнотація:
Nuclear location sequence-mediated binding of karyophilic proteins to the nuclear pore complexes is one of the earliest steps in nuclear protein import. We previously identified two cytosolic proteins that reconstitute this step in a permeabilized cell assay: the 54/56-kD NLS receptor and p97. A monoclonal antibody to p97 localizes the protein to the cytoplasm and the nuclear envelope. p97 is extracted from nuclear envelopes under the same conditions as the O-glycosylated nucleoporins indicating a tight association with the pore complex. The antibody inhibits import in a permeabilized cell assay but does not affect binding of karyophiles to the nuclear pore complex. Immunodepletion of p97 renders the cytosol inactive for import and identifies at least three other cytosolic proteins that interact with p97. cDNA cloning of p97 shows that it is a unique protein containing 23 cysteine residues. Recombinant p97 binds zinc and a bound metal ion is required for the nuclear envelope binding activity of the protein.
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Froschauer, Elisabeth M., Nicole Rietzschel, Melanie R. Hassler, Markus Binder, Rudolf J. Schweyen, Roland Lill, Ulrich Mühlenhoff, and Gerlinde Wiesenberger. "The mitochondrial carrier Rim2 co-imports pyrimidine nucleotides and iron." Biochemical Journal 455, no. 1 (September 13, 2013): 57–65. http://dx.doi.org/10.1042/bj20130144.
Повний текст джерелаАнотація:
Mitochondrial iron uptake is of key importance both for organelle function and cellular iron homoeostasis. The mitochondrial carrier family members Mrs3 and Mrs4 (homologues of vertebrate mitoferrin) function in organellar iron supply, yet other low efficiency transporters may exist. In Saccharomyces cerevisiae, overexpression of RIM2 (MRS12) encoding a mitochondrial pyrimidine nucleotide transporter can overcome the iron-related phenotypes of strains lacking both MRS3 and MRS4. In the present study we show by in vitro transport studies that Rim2 mediates the transport of iron and other divalent metal ions across the mitochondrial inner membrane in a pyrimidine nucleotide-dependent fashion. Mutations in the proposed substrate-binding site of Rim2 prevent both pyrimidine nucleotide and divalent ion transport. These results document that Rim2 catalyses the co-import of pyrimidine nucleotides and divalent metal ions including ferrous iron. The deletion of RIM2 alone has no significant effect on mitochondrial iron supply, Fe–S protein maturation and haem synthesis. However, RIM2 deletion in mrs3/4Δ cells aggravates their Fe–S protein maturation defect. We conclude that under normal physiological conditions Rim2 does not play a significant role in mitochondrial iron acquisition, yet, in the absence of the main iron transporters Mrs3 and Mrs4, this carrier can supply the mitochondrial matrix with iron in a pyrimidine-nucleotide-dependent fashion.
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Lewicka, Ewa, Katarzyna Guzik, and Krzysztof Galos. "On the Possibilities of Critical Raw Materials Production from the EU’s Primary Sources." Resources 10, no. 5 (May 17, 2021): 50. http://dx.doi.org/10.3390/resources10050050.
Повний текст джерелаАнотація:
Sufficient supplies of critical raw materials (CRMs) for rapidly developing technologies, e.g., Li-ion batteries, wind turbines, photovoltaics, digitization, etc., have become one of the main economic challenges for the EU. Due to growing import dependency and associated risk of supply disruptions of these raw materials from third countries, there is a need to encourage their domestic production. This is an important starting point for EU value chains crucial for the sustainable economic growth of the whole Union. This contribution has evaluated the possibilities of CRMs supply from the EU’s primary sources. A three-step approach, including an assessment of CRMs’ importance for the EU’s economic growth, their significance in at least two of the three strategic industrial sectors (i.e., renewable energy, e-mobility, defense and aerospace), and their potential availability from EU mineral deposits, has been applied. Results of the analysis have shown that, of 29 critical mineral raw materials (according to the 2020 EC list), the potential to develop manufacturing from the Union mineral deposits exists for 11 CRMs, i.e., cobalt, graphite (natural), HREE, LREE, lithium, magnesium, niobium, PGMs, silicon metal, titanium, and tungsten, while some other CRMs, namely gallium, germanium, indium, and vanadium can be recovered as by-products. Measures to mitigate EU import dependency have been also proposed.
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Foot, Natalie J., Yew Ann Leong, Loretta E. Dorstyn, Hazel E. Dalton, Kristen Ho, Lin Zhao, Michael D. Garrick, Baoli Yang, Devendra Hiwase, and Sharad Kumar. "Ndfip1-deficient mice have impaired DMT1 regulation and iron homeostasis." Blood 117, no. 2 (January 13, 2011): 638–46. http://dx.doi.org/10.1182/blood-2010-07-295287.
Повний текст джерелаАнотація:
Abstract The divalent metal ion transporter DMT1 is critical for nonheme iron import. We have previously shown that DMT1 is regulated in vitro by ubiquitination that is facilitated by the adaptor proteins Ndfip1 and Ndfip2. Here we report that in Ndfip1−/− mice fed a low- iron diet, DMT1 expression and activity in duodenal enterocytes are significant higher than in the wild-type animals. This correlates with an increase in serum iron levels and transferrin saturation. Liver and spleen iron stores were also increased in Ndfip1−/− mice fed a normal diet. Counterintuitive to the increase in iron uptake, Ndfip1−/− mice fed a low iron diet develop severe microcytic, hypochromic anemia. We demonstrate that this is due to a combination of iron deficiency and inflammatory disease in Ndfip1−/− mice, because Ndfip1−/−/Rag1−/− immunodeficient mice fed a low iron diet did not develop anemia and showed an iron overload phenotype. These data demonstrate that Ndfip1 is a critical mediator of DMT1 regulation in vivo, particularly under iron restricted conditions.
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Krenn, B. M., E. Gaudernak, B. Holzer, K. Lanke, F. J. M. Van Kuppeveld, and J. Seipelt. "Antiviral Activity of the Zinc Ionophores Pyrithione and Hinokitiol against Picornavirus Infections." Journal of Virology 83, no. 1 (October 15, 2008): 58–64. http://dx.doi.org/10.1128/jvi.01543-08.
Повний текст джерелаАнотація:
ABSTRACT We have discovered two metal ion binding compounds, pyrithione (PT) and hinokitiol (HK), that efficiently inhibit human rhinovirus, coxsackievirus, and mengovirus multiplication. Early stages of virus infection are unaffected by these compounds. However, the cleavage of the cellular eukaryotic translation initiation factor eIF4GI by the rhinoviral 2A protease was abolished in the presence of PT and HK. We further show that these compounds inhibit picornavirus replication by interfering with proper processing of the viral polyprotein. In addition, we provide evidence that these structurally unrelated compounds lead to a rapid import of extracellular zinc ions into cells. Imported Zn2+ was found to be localized in punctate structures, as well as in mitochondria. The observed elevated level of zinc ions was reversible when the compounds were removed. As the antiviral activity of these compounds requires the continuous presence of the zinc ionophore PT, HK, or pyrrolidine-dithiocarbamate, the requirement for zinc ions for the antiviral activity is further substantiated. Therefore, an increase in intracellular zinc levels provides the basis for a new antipicornavirus mechanism.
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Lasorsa, Alessia, Giovanni Natile, Antonio Rosato, Francesco Tadini-Buoninsegni, and Fabio Arnesano. "Monitoring Interactions Inside Cells by Advanced Spectroscopies: Overview of Copper Transporters and Cisplatin." Current Medicinal Chemistry 25, no. 4 (February 12, 2018): 462–77. http://dx.doi.org/10.2174/0929867324666171110141311.
Повний текст джерелаАнотація:
Background: Resistance, either at the onset of the treatment or developed after an initial positive response, is a major limitation of antitumor therapy. In the case of platinum- based drugs, copper transporters have been found to interfere with drug trafficking by facilitating the import or favoring the platinum export and inactivation. Methods: The use of powerful spectroscopic, spectrometric and computational methods has allowed a deep structural insight into the mode of interaction of platinum drugs with the metal-binding domains of the transporter proteins. Results: This review article focuses on the mode in which platinum drugs can compete with copper ion for binding to transport proteins and consequent structural and biological effects. Three types of transporters are discussed in detail: copper transporter 1 (Ctr1), the major responsible for Cu+ uptake; antioxidant-1 copper chaperone (Atox1), responsible for copper transfer within the cytoplasm; and copper ATPases (ATP7A/B), responsible for copper export into specific subcellular compartments and outside the cell. Conclusion: The body of knowledge summarized in this review can help in shaping current chemotherapy to optimize the efficacy of platinum drugs (particularly in relation to resistance) and to mitigate adverse effects on copper metabolism.
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Morkunas, Iwona, Agnieszka Woźniak, Van Mai, Renata Rucińska-Sobkowiak, and Philippe Jeandet. "The Role of Heavy Metals in Plant Response to Biotic Stress." Molecules 23, no. 9 (September 11, 2018): 2320. http://dx.doi.org/10.3390/molecules23092320.
Повний текст джерелаАнотація:
The present review discusses the impact of heavy metals on the growth of plants at different concentrations, paying particular attention to the hormesis effect. Within the past decade, study of the hormesis phenomenon has generated considerable interest because it was considered not only in the framework of plant growth stimulation but also as an adaptive response of plants to a low level of stress which in turn can play an important role in their responses to other stress factors. In this review, we focused on the defence mechanisms of plants as a response to different metal ion doses and during the crosstalk between metal ions and biotic stressors such as insects and pathogenic fungi. Issues relating to metal ion acquisition and ion homeostasis that may be essential for the survival of plants, pathogens and herbivores competing in the same environment were highlighted. Besides, the influence of heavy metals on insects, especially aphids and pathogenic fungi, was shown. Our intention was also to shed light on the relationship between heavy metals deposition in the environment and ecological communities formed under a strong selective pressure.
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Pratidina, Ellen Ayuningtyas, Eko Suhartono, and Bambang Setiawan. "IMPACT OF HEAVY METALS ON HEXOKINASE ISOFORMS: AN IN SILICO STUDY." Berkala Kedokteran 18, no. 1 (March 21, 2022): 29. http://dx.doi.org/10.20527/jbk.v18i1.12801.
Повний текст джерелаАнотація:
Abstract: Coal mining activities in South Kalimantan produce waste that is very dangerous if not processed wisely. Coal waste produces heavy metals cadmium and mercury that can pollute the environment. Heavy metals that enter the human body will cause negative impacts in the field of health such as the disruption of the glycolysis process in humans. The purpose of this study was determine the interaction of heavy metals which is cadmium and mercury against hexokinase enzymes using hexokinase enzymes type I, II, III with PDB ID : 4F9O, 2NZT, 3HM8 taken from Protein Data Bank and using the molecular docking website MIB: Metal Ion Binding Site Prediction and Docking server. Docking results will be visualized using chimera app version 1.15. Molecular docking of the heavy metals cadmium and mercury can interact with all three types of hexokinase enzymes. Cadmium metal ions bind hydrophobicly to amino acid residues of hexokinase enzymes type I, II, and III, while mercury metal ions bind covalently coordinate with amino acid residues of hexokinase enzymes type I and III. Mercury metal ions bind more strongly than cadmium metal ions. Of the three types of hexokinase enzymes, mercury metal ions bind most strongly with hexokinase enzyme type II because mercury ions bind to the active site of the three amino acid residues of hexokinase enzymes type II.Keywords: Cadmium ; hexokinase enzyme ; mercury ; molecular docking
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Saga, Koichiro. "Gettering Behavior of Transition Metals in Low Energy, High Dose Ion Implanted Silicon." Solid State Phenomena 187 (April 2012): 283–86. http://dx.doi.org/10.4028/www.scientific.net/ssp.187.283.
Повний текст джерелаАнотація:
Metallic contamination on silicon surfaces has a detrimental impact on ULSI device performance and yield. Surface metal impurities degrade gate oxide integrity, while metal impurities dissolved in silicon provide recombination centers, resulting in junction leakage. Surface metal impurities penetrate silicon by the collision with dopant during ion implantation and are also diffused in silicon by subsequent annealing [. If metal impurities are present around junctions, they can cause junction leakage. In order to avoid the junction leakage, metal impurities must be away from junction. It was reported that iron can be gettered in the region of dopants implanted at high energy [. On the other hand, little work has been reported on the behavior of metal impurities in shallow junction. In this study, the gettering behavior of various transition metals in low-energy and high-dose ion-implanted silicon has been demonstrated.
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Rink, Ingrid, Faisal Wali, and D. Martin Knotter. "Impact of Metal-Ion Contaminated Silica Particles on Gate Oxide Integrity." Solid State Phenomena 145-146 (January 2009): 131–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.145-146.131.
Повний текст джерелаАнотація:
The impact of metal-ion contamination (present on wafer surface before oxidation) on gate oxide integrity (GOI) is well known in literature, which is not the case for clean silica particles [1, 2]. However, it is known that particles present in ultra-pure water (UPW) decrease the random yield in semiconductor manufacturing [3]. The presence of silica in UPW is common knowledge. UPW has also a certain content of metal ions, which can be attached to silica. That means, when a wafer is in contact with UPW metal ion can directly and/or in form of a silica-metal conglomerate be attached to the wafer surface. That means, it is not known in which form metal-ion contamination will deteriorate GOI the most. In order to receive more clarity in this field a short-loop study was set up, where we want distinguish between the impacts of - low metal ion contamination (Calcium), - clean silica particles (330nm) contamination, - silica particles with metal-ion core (330nm) contamination, and - metal-ion contamination at similar concentration as the metal-ion core of the particles on GOI (uniform and none uniform distribution).
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Alshaeghli1, Hiba Abd albast Hashim, Riadh Abas Abdul Jabar, and Hussain Hassan Kharnoob2. "Distribution of some heavy metals in the sediments of Tigris river from sewage of Thermal Electrical Station at Baiji City in Salah-aldin Governorate-Iraq." Tikrit Journal of Pure Science 25, no. 1 (February 2, 2020): 52. http://dx.doi.org/10.25130/j.v25i1.935.
Повний текст джерелаАнотація:
This study was conducted to determine four heavy metals including copper, zinc, lead and cadmium in the sediments of the Tigris river for a distance of 3,500 km for the time period autumn2012 – summer 2013.This is the first time that such a study carried out by the river sediments so studies on the Tigris river about sequential extraction to compare them with the results of the research not available, total concentrations recorded of Cu )11.23-12.1)µg/g, Zn (39.6-41.03) µg/g, Pb (115.82-117.34) µg/g,Cd (4.1-4.34) µg/g dry weight, the distribution in the sediment layers, exchangeable metal ion recorded of Cu (0.42-0.44) µg/g, Zn (0.32-0.33) µg/g, Pb (0.22-0.25) µg/g, Cd (0.15-0.17) µg/g dry weight, and layer of carbonate bound of Cu( 1.6-1.63) µg/g ,Zn (4.47-6.71) µg/g, Pb (0.2-0.22) µg/g , Cd (1.44-2.17) µg/g dry weight, and the metal layer of Cu (1.26-1.41) µg/g, Zn (15.84-17.07) µg/g, Pb (46.38-49.46) µg/g, Cd (1.9-2.17) µg/g dry weight, concentration of organic layer Cu (7.85-8.67) µg/g, Zn (17.63-17.96) µg/g, Pb (68.57-67.48) µg/g, Cd (0.58-0.86) µg/g dry weight. The arrangement of total concentration Pb>Zn>Cu>Cd (4,42-12,09-41,69-116,88) µg/g dry weight. Distribution of Cu organic layer> carbonate bound> metal layer> exchangeable metal ion (8,41-1,78-1.52-0.35) µg/g dry weight, Zn metal layer> organic layer> carbonate bound> exchangeable metal ion (18.99-17,58-5.52-0.29) µg/g dry weight, Pb organic layer>metal layer> exchangeable metal ion> carbonate bound (66.42-49.81-0.22-0.2) µg/g dry weight, Cd metal layer> carbonate bound> organic layer> exchangeable metal ion (2.02-1.87-0.91-0.18) µg/g dry weight .The high concentration recorded in four station, these results indicated that the possibility of using sequential extraction for the detection of the distribution of metals and determine the impact of diversity through release them to the aquatic environment, all concentration mentioned are rate they aren’t single value.
http://dx.doi.org/10.25130/tjps.25.2020.010
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Kancharla, Vidhyullatha, Sajid Bashir, Jingbo L. Liu, Oscar M. Ramirez, Peter J. Derrick, and Kyle A. Beran. "Effect of metal surfaces on matrix-assisted laser desorption/ionization analyte peak intensities." European Journal of Mass Spectrometry 23, no. 5 (September 18, 2017): 287–99. http://dx.doi.org/10.1177/1469066717712694.
Повний текст джерелаАнотація:
Different metal surfaces in the form of transmission electron microscope grids were examined as support surfaces in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with a view towards enhancement of peptide signal intensity. The observed enhancement between 5-fold and 20-fold relative to the normal stainless steel slide was investigated by applying the thermal desorption model for matrix-assisted laser desorption/ionization. A simple model evaluates the impact that the thermal properties of the metals have on the ion yield of the analyte. It was observed that there was not a direct, or strong, correlation between the thermal properties of the metals and the corresponding ion yield of the peptides. The effects of both fixed and variable laser irradiances versus ion yield were also examined for the respective metals studied. In all cases the use of transmission electron microscope grids required much lower laser irradiances in order to generate similar peak intensities as those observed with a stainless steel surface.
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Yan, Li, Xue Feng An, Hai Chao Cui, and Xiao Su Yi. "Studies on Low-Velocity Impact Damage of Metal Ion Implanted Composite Laminates." Advanced Materials Research 311-313 (August 2011): 37–42. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.37.
Повний текст джерелаАнотація:
composite laminates, metal ion implantation, low-velocity impact damage, BVID Abstract. Metal ion implantation was carried out on composite laminates to modify the surface properties, so that after low-velocity impact barely visible impact damage (BVID) was easy to realize. Surface topography of laminates was observed by SEM. Microhardness and drop-weight impact was tested on composite laminates. The results showed that after metal ion implantation microhardness of laminates increased obviously and resin was easy to generate plastic deforming. Dent depth had been improved so as to realize visible impact damage more easily. And compression-after-impact (CAI) had not decreased. Comparison with Ti ion implantation, Cu ion implantation had better influence on realizing visible impact damage (VID).
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Pei, Liang. "Features of Metallic Ion Distribution in Non-Traditional Water Agricultural Applications in Sandy Loam in an Arid Area." Sustainability 14, no. 17 (September 5, 2022): 11080. http://dx.doi.org/10.3390/su141711080.
Повний текст джерелаАнотація:
Sandy loam is the main soil in the arid area of North China, which leads to serious water shortage. Therefore, the utilization of non-traditional water is necessary. However, there are many metal mining areas in the northern arid area. The mining process of these metal mines causes the pollution of surrounding water sources. It is important to study the distribution of pollutants in the process of unconventional water utilization around metal mines. In view of the above problems, a field test area was established near a mining area in a northern province to carry out research on non-traditional agricultural water applications. The influence of non-traditional agricultural water on pollutant distribution in balsam pear and sandy loam irrigation areas around a loam metal mine was analyzed. By discussing the influence of non-traditional water output after secondary treatment on the content and distribution characteristics of heavy metals in balsam pear in the sandy loam irrigation area around the metal mine, the distribution rules of heavy metals in the soil crop system under different non-traditional hydroponics conditions in the sandy loam irrigation area around the metal mine were analyzed. The results show that under different non-traditional agricultural water consumption conditions, there is no significant difference in terms of the content of heavy metals in the sandy loam irrigation area around the metal mine. The non-traditional water used for short-term agricultural application does not cause pollution of the loam environment and crops, nor does it cause heavy metal accumulation in the sandy loam irrigation area around the metal mine. The input and output have a minimal impact on the balance of heavy metals in the sandy loam irrigation area around the metal mine. The presented research results provide a scientific basis for agricultural utilization of non-traditional water around mining areas in arid areas.
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Karavoltsos, Sotirios, Aikaterini Sakellari, Vassilia J. Sinanoglou, Panagiotis Zoumpoulakis, Marta Plavšić, Manos Dassenakis, and Nick Kalogeropoulos. "Copper Complexing Capacity and Trace Metal Content in Common and Balsamic Vinegars: Impact of Organic Matter." Molecules 25, no. 4 (February 15, 2020): 861. http://dx.doi.org/10.3390/molecules25040861.
Повний текст джерелаАнотація:
Complex formation is among the mechanisms affecting metal bioaccessibility. Hence, the quantification of organic metal complexation in food items is of interest. Organic ligands in solutions of environmental and/or food origin function as buffering agents against small changes in dissolved metal concentrations, being able to maintain free metal ion concentrations below the toxicity threshold. Organic matter in vinegars consists of bioactive compounds, such as polyphenols, Maillard reaction endproducts, etc., capable of complexing metal ions. Furthermore, transition metal ions are considered as micronutrients essential for living organisms exerting a crucial role in metabolic processes. In this study, differential pulse anodic stripping voltammetry (DPASV), a sensitive electrochemical technique considered to be a powerful tool for the study of metal speciation, was applied for the first time in vinegar samples. The concentrations of Cu complexing ligands (LT) in 43 vinegars retailed in Greece varied between 0.05 and 52 μM, with the highest median concentration determined in balsamic vinegars (14 μM), compared to that of common vinegars (0.86 μM). In 21% of the vinegar samples examined, LT values were exceeded by the corresponding total Cu concentrations, indicating the presence of free Cu ion and/or bound within labile inorganic/organic complexes. Red grape balsamic vinegars exhibited the highest density of Cu ligands per mass unit of organic matter compared to other foodstuffs such as herbal infusions, coffee brews, and beers. Among the 16 metals determined in vinegars, Pb is of particular importance from a toxicological point of view, whereas further investigation is required regarding potential Rb biomagnification.
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Bekker, Day, and Smith. "Changes in Metal Ion Concentrations in a Chardonnay Wine Related to Oxygen Exposure during Vinification." Molecules 24, no. 8 (April 17, 2019): 1523. http://dx.doi.org/10.3390/molecules24081523.
Повний текст джерелаАнотація:
The impact of oxygen exposure during winemaking on metal ion concentrations in wine were investigated throughout the winemaking process in a Chardonnay wine. The concentrations of Al, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Sn, and Zn were determined using inductively coupled plasma-mass spectrometry. Oxygen exposure significantly impacted 13 metal ions at different phases of winemaking. However, only the concentrations of Cr, Cu, and Fe were impacted by early oxygen exposure during pressing, with lower Cr and Cu concentrations in wines that were aerobically pressed and lower concentrations of Fe in wines that were inertly pressed. The sequestering of Al, Cu, Ni, and Zn by wine lees was significantly affected by oxygen treatment, with lees collected from wines that were treated oxidatively sequestering significantly greater amounts of Cu and Zn and removing these metals from the wine supernatant. The metal ion that was most affected by oxygen exposure during pressing and handling was Cu, with significantly lower Cu measured in wines that were produced under oxidative conditions. It is known that elevated Cu concentrations have negative implications for wine aroma and flavour. This study demonstrated that oxygen management during winemaking significantly impacts metal ion concentrations in lees and wine, which may decrease the risk of developing taints and faults.
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Negi, Ankita, Arpita Negi, Rajesh Kumar, Bhuvnesh Kumar, Sushil Kumar Joshi, and Narendra Singh Bhandari. "Harmful Impacts of Heavy Metals and Utility of Biosorption Technique for Their Removal from Wastewater: A Review." Journal of Chemistry, Environmental Sciences and its Applications 8, no. 1 (January 3, 2022): 1–17. http://dx.doi.org/10.15415/jce.2021.81001.
Повний текст джерелаАнотація:
The increasing number of efluents discharged from the source of water (urban, industrial, agricultural etc.), is resulting in a higher concentration of heavy metals in the source. Heavy metals have a density of over 5g/cm3 to the metals. These are toxic, mutagenic, carcinogenic and resistant in watery and non-aquatic environments and impact water and non-water bodies seriously by substituting the basic metals of the same function. The extraction from the wastewater can be done in numerous techniques for example using an ion replacement, membrane filtration, osmosis, etc. This study discusses the adverse effects of heavy metals on the human body, the benefits of biosorption over traditional approaches for removal of heavy metals, the different biosorbents used to extract heavy metals and concerning issues regarding its commercial use, offering a wider viewpoint for the diversity of biosorbents and utilization of biosorption technique. It is evident from the profound literature survey that pH, biosorbent particle size, contact time, initial metal ion concentration, presence of chelating ligands etc. are some factors that affect the rate and extent of biosorption.
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Zuschlag, Annika, Michail Schwab, Dorit Merhof, and Giso Hahn. "Transition Metal Precipitates in Mc Si: A New Detection Method Using 3D-FIB." Solid State Phenomena 205-206 (October 2013): 136–41. http://dx.doi.org/10.4028/www.scientific.net/ssp.205-206.136.
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To investigate transition metal precipitates in Si, synchrotron based measurements, like micro x-ray fluorescence (μXRF) or detailed transmission electron microscopy (TEM) studies, are usually necessary. Transition metals are among the most detrimental defects in multi-crystalline (mc) silicon material for solar cell applications, due to their impact on minority charge carrier lifetime and possible shunt formation. We present another possibility to investigate transition metal precipitates by 3-dimensional focused ion beam (3D-FIB) cutting using a combined scanning electron microscope (SEM) SEM-FIB-system. This method is able to detect transition metal precipitates down to 5 nm in radius and provides additional information about the 3D shape, size and spatial distribution of the precipitates.
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Hu, Ri Cha, and Li Bo Sun. "Migration Patterns of Heavy Metals in Soil in Wastewater Irrigation Area in the Suburb of Eastern Inner Mongolia." Advanced Materials Research 343-344 (September 2011): 340–43. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.340.
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Based on the soil test of heavy metals in wastewater irrigation area in eastern Inner Mongolia, this paper analyses the content of heavy metals Cr, Cu, Cd, Pb in different layers of soil samples and reveals the internal relations between heavy metal concentration gradient in the vertical direction and soil properties, thus providing a scientific basis to guide sewage irrigation, solve the problem of water shortage in wastewater irrigation area and carry out environmental impact assessment. Soil is an important subsystem in natural environmental systems, through which many pollutants, especially heavy metals, produced by human activities, enter the food chain and ultimately do harm to human health. Currently, heavy metal ion contamination to the soil caused by wastewater irrigation has become one of the focuses in the study of soil chemistry and agricultural environment pollution. For this reason, it is particularly important to study the migration mechanism of heavy metals in soil and to provide a reliable theoretical basis for the prevention and management of soil contaminants.
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Melendez-Zamudio, Miguel, Kevina Chavda, and Michael A. Brook. "Chelating Silicone Dendrons: Trying to Impact Organisms by Disrupting Ions at Interfaces." Molecules 27, no. 6 (March 14, 2022): 1869. http://dx.doi.org/10.3390/molecules27061869.
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The viability of pathogens at interfaces can be disrupted by the presence of (cationic) charge and chelating groups. We report on the synthesis of silicone dendrimers and linear polymers based on a motif of hexadentate ligands with the ability to capture and deliver metal ions. Mono-, di- or trialkoxysilanes are converted in G1 to analogous vinylsilicones and then, iteratively using the Piers-Rubinsztajn reaction and hydrosilylation, each vinyl group is transformed into a trivinyl cluster at G2. The thiol-ene reaction with cysteamine or 3-mercaptopropionic acid and the trivinyl cluster leads to hexadentate ligands 3 × N–S or 3 × HOOC–S. The compounds were shown to effectively capture a variety of metals ions. Copper ion chelation was pursued in more detail, because of its toxicity. On average, metal ions form chelates with 2.4 of the three ligands in a cluster. Upon chelation, viscous oils are converted to (very) soft elastomers. Most of the ions could be stripped from the elastomers using aqueous EDTA solutions, demonstrating the ability of the silicones to both sequester and deliver ions. However, complete ion removal is not observed; at equilibrium, the silicones remain ionically crosslinked.
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FISHER, DIMITRI V., ZOHAR HENIS, SHALOM ELIEZER, and JUERGEN MEYER-TER-VEHN. "Core holes, charge disorder, and transition from metallic to plasma properties in ultrashort pulse irradiation of metals." Laser and Particle Beams 24, no. 1 (March 2006): 81–94. http://dx.doi.org/10.1017/s0263034606060137.
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We study the details of a gradual change in electron properties from those of a nearly-free-electron (NFE) metal to those of a strongly-coupled plasma, in ultrashort pulse energy deposition in solid metal targets. Time scales shorter than those of a target surface layer expansion are considered. Both the case of an optical laser (visible or near infrared wavelengths range) and of a free electron laser (vacuum ultraviolet or X-ray) are treated. The mechanisms responsible for the change in electron behavior are isochoric melting, lattice charge disordering, and electron mean free path reduction. We find that the transition from metal to plasma usually occurs via an intermediate stage of a charge-disordered solid (solid plasma), in which ions are at their lattice sites but the ionization stages of individual ions differ due to ionization from localized bound states. Charge disordered state formation is very rapid (typically, few femtoseconds or few tens of femtoseconds). Pathway to charge-disordered state differs in simple metals and in noble metals. Probabilities are derived for electron impact ionization and 3-body recombination of a bound ionic state in solid-density medium, applicable both in metal and in plasma regime. An evolution of energy coupling between electron and ion subsystems, from metallic electron-phonon (e-ph) to plasma electron-ion (e-i) coupling, is considered. Substantial increase in coupling parameter is expected as a result of charge disorder.
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Foday Jr, Edward Hingha, Bai Bo, and Xiaohui Xu. "Removal of Toxic Heavy Metals from Contaminated Aqueous Solutions Using Seaweeds: A Review." Sustainability 13, no. 21 (November 8, 2021): 12311. http://dx.doi.org/10.3390/su132112311.
Повний текст джерелаАнотація:
Heavy metal contamination affects lives with concomitant environmental pollution, and seaweed has emerged as a remedy with the ability to save the ecosystem, due to its eco-friendliness, affordability, availability, and effective metal ion removal rate. Heavy metals are intrinsic toxicants that are known to induce damage to multiple organs, especially when subjected to excess exposure. With respect to these growing concerns, this review presents the preferred sorption material among the many natural sorption materials. The use of seaweeds to treat contaminated solutions has demonstrated outstanding results when compared to other materials. The sorption of metal ions using dead seaweed biomass offers a comparative advantage over other natural sorption materials. This article summarizes the impact of heavy metals on the environment, and why dead seaweed biomass is regarded as the leading remediation material among the available materials. This article also showcases the biosorption mechanism of dead seaweed biomass and its effectiveness as a useful, cheap, and affordable bioremediation material.
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Liu, Jun Yan, Jin Guo Wang, Yun Hai Yu, and Na Wang. "Application of Magnesium and its Alloys in Biodegradable Vascular Stent." Materials Science Forum 987 (April 2020): 77–82. http://dx.doi.org/10.4028/www.scientific.net/msf.987.77.
Повний текст джерелаАнотація:
Biodegradable vascular stent is mainly made of materials that can be naturally decomposed. Magnesium and its alloys have excellent mechanical properties and biocompatibility. The vascular stent made of magnesium and its alloys has the unique advantages of strength of metal scaffolds and bioabsorbability of degradable polymer scaffolds. Due to the special microenvironment inside the blood vessels, the stent should have good resistance against corrosion. After implantation of metal materials for human tissue repair, the surface oxidation film spontaneously formed in the air will react with the human physiological environment. The nature of the interface between materials and tissues will have a certain impact on the corrosion resistance of metals and the degree of metal ion release, thus determining the biocompatibility of materials.
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Quattrini, Federico, Josep Galceran, Carlos Rey-Castro, Jaume Puy, and Claude Fortin. "Assessment of labilities of metal complexes with the dynamic ion exchange technique." Environmental Chemistry 16, no. 3 (2019): 151. http://dx.doi.org/10.1071/en18202.
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Environmental contextIn natural waters, the impact of metals on biota is modulated by their binding with ligands. Ion-exchange techniques can provide information about metal-ligand complexes in solution, which can be linked to metal bioavailability in natural waters. We investigate modelling approaches to interpreting data from ion-exchange experiments to help elucidate the contribution of a particular complex to the overall metal uptake. AbstractThe dynamic ion exchange technique (DIET) is proposed to provide speciation information, which can be used to establish links with metal bioavailability in natural waters. The experimental setup consists of a few milligrams of a sulfonic acid type ion exchange resin packed in a plastic microcolumn that is coupled to a peristaltic pump for a sample to interact with the resin which is subsequently eluted. The evolution of both the accumulated number of moles in the resin and the concentration of the effluent can provide information on the dissociation of different metal-ligand complexes when compared with the transport properties. This information can be converted into the lability degree of a given complex or the DIET concentration cDIET, which accounts for the labile fraction contributing to the metal accumulation by the resin column at the operation conditions. cDIET can be extended to columns containing chelating resins (such as those with Chelex) or to chromatography. A comprehensive modelling of the involved phenomena (such as diffusion, advection, reaction kinetics and electrostatic partitioning) leads to the quantitative interpretation of the accumulation time series (accumulation curves) or effluent evolution (breakthrough curves). Particularly simple analytical expressions can be used for short exposure times, when a (quasi) steady-state is attained. These models have been checked against the results from complexes of Cu and Ni with ligands, such as ethylenediamine, and ethylenediaminetetraacetic, iminodiacetic, glutamic, salicylic, malonic and malic acids, which yield complexes with contrasting charges. Caution is advised when estimating the free metal fraction from DIET measurements, as cDIET and the free metal concentration can be considered to be equal only in the case of extremely inert complexes.
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Inoue, Masahiko, Shinji Tanaka, Junji Yuhara, and Kenji Morita. "Ion impact desorption of metal atoms from -metal surfaces." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 58, no. 3-4 (June 1991): 411–16. http://dx.doi.org/10.1016/0168-583x(91)95878-h.
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Salih, Ali Mohammed, Craig Williams, and Polla Khanaqa. "Kinetic Studies of Heavy Metal Removal from Industrial Wastewater by Using Natural Zeolite." UKH Journal of Science and Engineering 5, no. 1 (June 30, 2021): 18–25. http://dx.doi.org/10.25079/ukhjse.v5n1y2021.pp18-25.
Повний текст джерелаАнотація:
The present work involves the study of the removal of Cu2+, Fe3+, Pb2+ and Zn2+ from synthetic metal solutions using natural zeolite. Laboratory experiments were used to investigate the efficiency of adsorbents in the uptake of heavy metals from industrial wastewater. The kinetic study was used to identify the effect of parameters that affect the rate of adsorption and evaluated their impact on the efficiency of the zeolite in the removal of heavy metals from industrial wastewater. Natural zeolite (clinoptilolite) as adsorbent contacted with multi-component synthetic solutions containing Cu2+, Fe3+, Pb2+ and Zn2+ ions without any pre-modifications and every hour 15 ml of the samples were filtered and taken for metal ion concentration analysis using the ICP-OES. The pH values were monitored and adjusted regularly. The results showed that the capacity of the adsorbents for the removal of heavy metals increased with a greater mass of absorbent, increased initial solution pH, increased agitation speed and higher solution concentration.
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Meyer, Katharina A. E., Kathleen A. Nickson, and Etienne Garand. "The impact of the electric field of metal ions on the vibrations and internal hydrogen bond strength in alkali metal ion di- and triglycine complexes." Journal of Chemical Physics 157, no. 17 (November 7, 2022): 174301. http://dx.doi.org/10.1063/5.0117311.
Повний текст джерелаАнотація:
Using infrared predissociation spectroscopy of cryogenic ions, we revisit the vibrational spectra of alkali metal ion (Li+, Na+, K+) di- and triglycine complexes. We assign their most stable conformation, which involves metal ion coordination to all C=O groups and an internal NH⋯NH2 hydrogen bond in the peptide backbone. An analysis of the spectral shifts of the OH and C=O stretching vibrations across the different metal ions and peptide chain lengths shows that these are largely caused by the electric field of the metal ion, which varies in strength as a function of the square of the distance. The metal ion–peptide interaction also remotely modulates the strength of internal hydrogen bonding in the peptide backbone via the weakening of the amide C=O bond, resulting in a decrease in internal hydrogen bond strength from Li+ > Na+ > K+.
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Saravanan, K. G., R. Prabu, A. R. Venkataramanan, and Eden Tekle Beyessa. "Impact of Different Electrolytes on the Machining Rate in ECM Process." Advances in Materials Science and Engineering 2021 (August 30, 2021): 1–6. http://dx.doi.org/10.1155/2021/1432300.
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Electrochemical machining is a nonconventional machining process in which the metal removal is achieved by the electricity and chemical solution known as an electrolyte. It is the reverse electrolysis process where the application of electricity facilitates the current travel in between anode and cathode. The mechanism of the ion movement is similar to the electrolysis process. Electrochemical machining (ECM) is a type of advanced machining process which employs electricity to perform the machining process on the workpiece. It is also known as a reverse electroplating process where metal removal is achieved instead of metal deposition on the metal surface. There are various parameters that affect the metal removal process in the ECM process, such as electrolyte, power supply, workpiece material, and tool material. The electrolyte is one of the key factors impacting the machining rate, surface finish, and reliability of the produced parts. In this project, a brief study is carried out regarding the electrochemical process and the electrolytes where the properties, functions, merits, and demerits are evaluated. The impact of the various electrolytes and their suitability for machining of various metals is also discussed. The findings of the effect produced by using the mixture of the electrolyte in the electrochemical machining process are discussed in this project. The effects of the complexing agents on the electrolyte and the electrochemical process as a whole are also reviewed.
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Kumudhavalli, D., and Ayyakannu Arumugam Napoleon. "A Mini Review on Arsenic and Cadmium Ion Detection Using Fluorescent-Colorimetric Sensors." ECS Transactions 107, no. 1 (April 24, 2022): 16833–42. http://dx.doi.org/10.1149/10701.16833ecst.
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Heavy metals with high atomic numbers, mass, and density are five times greater than water. They are naturally occurring elements and widely distributed in the environment due to their numerous applications like agricultural, industrial, domestic, technological, and medical fields increasing issues about their potential impact on the environment and human health. In this mini review, we focused on cadmium and arsenic metals. Cadmium is also the non-essential toxic heavy metal element found naturally in the earth's crust, and it is easily affected by plants’ movements through the food cycle and also causes harm to live beings. Arsenic is a common element found in low amounts in almost all environmental compartments. Chemosensors play a pivotal role in environmental and analytical chemistry. Chemosensors can detect enzymes, anions, and hazardous heavy metal ions with excellent selectivity and sensitivity at a low cost. Colorimetric chemosensors are instruments that convert chemical data into analytically relevant signals that can be viewed with the naked eye. Fluorescent-based chemosensors for cations, anions, and neutral analytes have been used in a wide range of applications.
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Wang, Qian, Dong Wei Li, and Guo Li Chen. "Research on Heavy Metal Pollution and Hazards of Tailings." Applied Mechanics and Materials 71-78 (July 2011): 876–81. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.876.
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Everyone knows heavy metals are inorganic pollutants with strong toxicity and typical pollutant needing preferentially control. In the metal mines of China, the tails that were piled up on the ground already have reached more than 4 billion tons, and this number increased 2 ×108 tons every year. The characteristics of metal mine tails mainly include: (1) the grain size is extremely fine; (2) The quantity in weight was very large; (3) the toxicity is very strong; (4) Transporting concentration is very low. The migration of heavy metals would impact the local environment, the safety of the downriver resident and the plowland, the food safety of livestock as well as the solid’s safety. Based on the characteristics of mine tailings impacting to environment, this paper estimates the pollution property, as well as studies the harm for the outside environment through the experiment of the gross analysis and the infusion toxicity analysis. This research takes Longdu tailings of Dahong Mountain for example to know the harm of heavy metal ion.
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Maranescu, Bianca, Lavinia Lupa, and Aurelia Visa. "Heavy metal removal from waste waters by phosphonate metal organic frameworks." Pure and Applied Chemistry 90, no. 1 (January 26, 2018): 35–47. http://dx.doi.org/10.1515/pac-2017-0307.
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AbstractThe increase attention in the area of phosphonate metal organic framework is exemplified with a variety of applications and a rich chemistry of these compounds. Water pollution caused by heavy metal ions is a major concern due to their toxicity to many life forms. In order to decrease the heavy metals impact upon the environment various technologies of water treatment such as: chemical sedimentation, ion exchange, redox process are studied. The tendency is to find a versatile and economical method of heavy metals removal from waste waters. Phosphonate metal organic frameworks were obtained by the reaction of Ni(CH3COO)2·4H2O, phosphonic acid (phosphonoacetic (CP), vinyl phosphonic acid (VP) and N,N-bis(phosphonomethyl)glycine (Gly)) in hydrothermal conditions. Coordination polymers synthesized were characterized by FTIR, XRD, scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The adsorption processes represent a very good alternative for heavy metals removal due to low costs and ease of operation. In the present paper the adsorption performance of the mentioned materials in the removal process of heavy metals from aqueous solutions, was studied using the batch method. The adsorption conditions were investigated by varying the initial pH, contact time and adsorbate initial concentration for chromium metal ions removal from aqueous solutions. It was found that the adsorption efficiency of the studied materials in the removal process of Cr(VI) ions from aqueous solutions is in the following order: Ni-CP<Ni-Gly≤Ni-VP.
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Tan, Hong Ling, Cong Ying Jia, Chao Xiang, and Ying Xiang Yang. "Impact Electrical Property of Alkali Metal Doped ZnO." Advanced Materials Research 468-471 (February 2012): 1501–7. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.1501.
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Calculate the electronic structure of alkali metal ion-doped Zn crystal, based on density functional theory (DFT) first-principles plane-wave ultra-soft pseudo-potential method. Analyze the band structure of alkali metal ion-doped ZnO crystal, and the electronic density of states. The results indicated that in theory, the doping of alkali metal ions are able to form a p-type ZnO semiconductor, and introduce in the deep acceptor levels. In the actual substitution process, the dopant ions may enter the interstitial site. Thus the alkali metal ions are tending to become donor interstitial impurities. In addition, since the ionic radius of K is larger than the ionic radiuses of Li and Na. And K+ formed the minimum acceptor level (0.078eV), which is a shallow acceptor level. K+ is better than Li+ and Na+ as a dopant. In short, they are not good p-type dopants.
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Kumar, Ameet, Aamna Balouch, Ashfaque Ahmed Pathan, Muhammad Saqaf Jagirani, Ali Muhammad Mahar, Muneeba Zubair, and Benazir Laghari. "Remediation of Nickel ion from wastewater by applying various techniques: a review." Acta Chemica Malaysia 3, no. 1 (June 1, 2019): 1–15. http://dx.doi.org/10.2478/acmy-2019-0001.
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Abstract The remediation of organic and inorganic pollutants from the aqueous environment has touched a certain level with the development of research. Environmental pollution is increasing day by day due to industrial activities which cause a negative effect on human health and the ecosystem. Nowadays, heavy metals have a special concern due to its toxicity, persistence and bioaccumulation in nature. Toxic metals like chromium, nickel, arsenic, lead, mercury, cadmium are the main contaminants of water because they are non-biodegradable in nature. Nickel is also a toxic metal, mostly used in industries because of its anticorrosion behaviour. As a consequence nickel is present in the wastage of electroplating, tableware, metal finishing, plastics manufacturing, nickel-cadmium batteries, fertilizers and mining industries and these waste have dangerous impact on the human health and environment and causes the diseases i.e. diarrhea, anemia, hepatitis, kidney damage, gastrointestinal distress, skin dermatitis, and central nervous system dysfunction. In the present review article, several techniques are discussed for the treatment of nickel from the industrial environment. The elimination of nickel from wastewater is not important only for economic purposes but also for environmental safety.
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Carey, Stephen, D. Martin Knotter, Eric Ooms, Johannes Boersma, Elfried van der Sar, Robbert Cop, Wim Gerritzen, Hans van Zadelhoff, and Henk Bouma. "Yield Impact of Backside Metal-Ion Contamination." Solid State Phenomena 187 (April 2012): 287–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.187.287.
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Small amounts (~1010 atms of Fe) of metal-ion contamination remains on local spots on the backside of the wafer. During a thermal process step, 30% of this contamination is transferred to the front side of the wafer where it causes in some specific cases substrate degradation. The source of the contamination is stainless-steel wafer pins that are used in wafer handling on for example litho tracks. This contamination is printed onto the backside wafer surface where two cleaning steps were not able to remove it. Figure 1. Wafer test: 3 clusters of devices failing due to the tripod signal.
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Zawierucha, Iwona, and Anna Nowik-Zajac. "Evaluation of permeable sorption barriers for removal of Cd(II) and Zn(II) ions from contaminated groundwater." Water Science and Technology 80, no. 3 (August 1, 2019): 448–57. http://dx.doi.org/10.2166/wst.2019.288.
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Abstract In the present study, continuous-flow column experiments (using glass column, Tygon tubing, and peristaltic pump Manostat Carter) were conducted to investigate the performance of permeable sorption barriers for the removal of cadmium and zinc from synthetic groundwater. Zeolite, ion-exchange resin and granular activated carbon as reactive materials were used. The effectiveness and stability of reactive materials were studied by monitoring of changes of metal ions concentration and selected background anions and cations concentration in groundwater during its flow through columns. Results showed that ion exchange resin was the most effective material of permeable reactive barrier (PRB). Performance of resin barrier remained effective (>99.5% metal ions removal) for the time corresponding to on average of about 10,000 min. The high efficiency of ion-exchange resin in PRB for removal of heavy metals from groundwater was coupled with its reactivity and long barrier lifetime. The breakthroughs in the column tests on activated carbon and zeolite using synthetic groundwater occurred much earlier as compared to resin. Therefore, the system using resin requires smaller amount to treat a given volume of groundwater as compared to other materials. Moreover, the presence of other ions did not impact on activity and permeability of barrier filled with resin.
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Zhou, Huimin, Tingping Ouyang, Yu Guo, Shasha Peng, Chenjian He, and Zhaoyu Zhu. "Assessment of Soil Heavy Metal Pollution and Its Ecological Risk for City Parks, Vicinity of a Landfill, and an Industrial Area within Guangzhou, South China." Applied Sciences 12, no. 18 (September 18, 2022): 9345. http://dx.doi.org/10.3390/app12189345.
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As a primary sink of pollutants, urban soil heavy metal pollution and its influence on urban residents and ecosystems has been becoming one of the most important environmental problems. In the present study, four indices, the Geoaccumulation index (Igeo), improved Nemerow index (IMN), degree of contamination (mCd), and contamination security index (CSI), as well as potential ecological risk (RI), were used to evaluate individual or integrated heavy metal pollution and its ecological risk for soil samples collected from city parks, the vicinity of a landfill, and an industrial area within the city of Guangzhou. The results indicated that the improved Nemerow index (IMN) calculated from the Geoaccumulation index was suitable for heavy metal pollution assessment of soils within landfills and industrial areas. As for soils collected from city parks, degree of contamination (mCd) was more suitable than IMN. Heavy metals Cd, Hg, Zn, and As were the main pollution elements in urban soils of Guangzhou. Potential ecological risks were mainly caused by Cd and Hg in urban soil of Guangzhou. Soil samples collected from city parks and the vicinity of the industrial area were moderately to highly and even extremely seriously polluted by heavy metals. Differing from the traditional cognition of the public, the ecological impact of heavy metal in soil in the vicinity of the landfill was similar to or even better than that within city parks.
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Azmat, Rafia, Ailyan Saleem, Waseem Ahmed, Abdul Qayyum, Hamed A. El-Serehy, and Sajid Ali. "The Investigation of the Impact of Toxicity of Metals on Oxygen-Evolving Complex in Spinacia oleracea." Antioxidants 11, no. 9 (September 13, 2022): 1802. http://dx.doi.org/10.3390/antiox11091802.
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The current article reported the investigation of metal toxicity on the oxygen-evolving complex (OEC) in Spinacia oleracea related to depletion in chloride ion concentration, an essential part of the photosystem (II). The greenhouse experiment was conducted where S. oleracea was cultivated in three replicates with control plants (plants “a”) treated with tap water. Moreover, 30 ppm of Cu2+ ion solution and Pb2+ ion solution was used to irrigate the rest of the plants, labeled as plants “b” and “c”, respectively, on alternative days. Advanced technologies such as Atomic Absorption Spectrophotometry (AAS), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and UV-visible Spectrophotometry were used to monitor the essential nutrients in leaves to validate the function of the photosystem (I and II). Reduced Cl− ions contents showed that both metals (Cu2+ and Pb2+) altered the essential elements of the oxygen-evolving complex (OEC) of photosystem (II), required to maintain the coordination structure of the Mn4CaO5 cluster. SEM analysis revealed the modified leaf structure of the S. oleracea under Cu2+ and Pb2+ accumulation due to which distorted cellular structure, reduced surface area, and the (shattered) stomatal opening compared to the plants “a” were observed. The EDS analysis of plants “b” and “c” showed high oxygen contents followed by reduced chloride contents over plants “a”, reflecting the infirmity of OEC to push out oxygen, which leads to generating oxidative stress. The lower pigment concentration in leaves of metal-contaminated plants “b” and “c” impacts carbon assimilation, which is linked to the reduced stomatal opening and influences the gaseous exchange rates. Additionally, increased contents of K+ and Ca2+ may be due to self-defense mechanisms under low chloride contents to speed up oxygen evolution to protect plants against oxidative stress. It was concluded that Cu2+ and Pb2+ metal toxicity influences essential Cl− and K+ contents, which modify the photosystem II system; subsequently, a reduced growth rate was observed.
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Habibpour, R., M. Dargahi, E. Kashi, and M. Bagherpour. "Comparative study on Ce (III) and La (III) solvent extraction and separation from a nitric acid medium by D2EHPA and Cyanex272." Metallurgical Research & Technology 115, no. 2 (2018): 207. http://dx.doi.org/10.1051/metal/2017083.
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The solvent extraction of Cerium(III) and Lanthanum(III) from nitric acid solution using the organophosphorous extractants Di-(2-ethyl hexyl) phosphate (D2EHPA) and di-2,4,4- trimethylpentyl phosphoric acid (Cyanex272) in kerosene was investigated. In this study, the magnitude of the extraction of Ce(III) was found to be more significant with Cyanex272 than D2EHPA. D2EHPA was found to be a better extractant for La(III). Among the two extractants, Cyanex272 was used for the separation of Ce from La in three stages with an extraction efficiency of 90.2% for Ce. A 556 mg/L Ce solution was used for the scrubbing of La with an efficiency of ≈34%, which required multi stage scrubbing. The study of thermodynamic parameters such as enthalpy, entropy, and Gibbs free energy impart the exothermic and non-spontaneous process. The chemical speciation curves for lanthanum and cerium in the aqueous phase as a function of pH showed that the free La(III) and Ce(III) metal ion species were largely predominate between a pH = 0 and pH = 7.
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Kumar, Rajeev, Jyoti Chawla, and Inderpreet Kaur. "Removal of cadmium ion from wastewater by carbon-based nanosorbents: a review." Journal of Water and Health 13, no. 1 (July 21, 2014): 18–33. http://dx.doi.org/10.2166/wh.2014.024.
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A green environment and a healthy life are dream projects of today's science and technology to save the world. Heavy metal ions in water affect both environment and human health. Cadmium has been identified as one of the heavy metals that causes acute or chronic toxic effects if ingested. Increasing use of cadmium in different technological fields has raised concern about its presence and removal from water/wastewater. Researchers have made many systematic efforts to remove heavy metals from water to reduce their impact on human beings and the environment. Adsorption is one of the best methods to remove heavy metals from water among the different proposed methods. This study explores carbon-based nanosorbents which have been proved as effective adsorbents for removal of cadmium ions from water. The adsorption efficiency of carbon-based nanosorbents is the main criterion to rank and select them for removal of cadmium ions from water. Toxicity, reusability and environmentally friendly characteristics of sorbents are also taken considered while ranking the suitable carbon-based nanosorbents for removal of cadmium ions from water.
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Saga, Koichiro. "Diffusion Behavior of Transition Metals Penetrating Silicon Substrate through Silicon Dioxides by Dopant Ion Implantation." Solid State Phenomena 195 (December 2012): 261–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.195.261.
Повний текст джерелаАнотація:
Metallic contamination on silicon surfaces has a detrimental impact on ULSI device performance and yield. Surface metal impurities degrade gate oxide integrity while metal impurities dissolved in silicon cause recombination centers and result in junction leakage. Surface metal impurities penetrate silicon by the colliding with dopant during ion implantation and are also diffused in silicon by subsequent annealing [. The diffusion behavior of metal impurities in silicon is well-known [. While metal impurities often penetrate silicon through the silicon oxide in ULSI processing, little work has been reported on the diffusion behavior of metal impurities penetrating silicon oxide. We demonstrated the diffusion behavior of metal impurities penetrating silicon substrates with different thickness of silicon oxide by the collision with dopant during ion implantation.
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Stetter, D., O. Dördelmann, and H. Overath. "Pilot scale studies on the removal of trace metal contaminations in drinking water treatment using chelating ion-exchange resins." Water Supply 2, no. 1 (January 1, 2002): 25–35. http://dx.doi.org/10.2166/ws.2002.0004.
Повний текст джерелаАнотація:
Increasing nickel concentrations in groundwaters are causing treatment problems in some locations in Germany and other European countries. Ion exchange treatment using iminodiacetic acid resin was studied under various conditions in a pilot scale plant. Breakthrough curves show that nickel, cadmium and lead concentrations of below 100 μg/L can easily be reduced to 1% of the feed concentration. Assuming a minimum removal rate of 95% the treated volumes ranged from 75,000 bed volumes up to 195,000 bed volumes depending on flow rate and calcium concentration. The process has no impact on other chemical and microbiological water quality parameters. Ideally the feed water should be free from turbidity, iron and manganese, otherwise head loss will grow very fast because of high filtration rates and the small diameter of resin beads used in this process. Nevertheless, the ion exchange resin can be backwashed without increasing the metal concentration in the effluent. Ion exchange using iminodiacetic resins is therefore a suitable treatment process for the removal of heavy metals from drinking water.
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Rozenberg, Julian Markovich, Margarita Kamynina, Maksim Sorokin, Marianna Zolotovskaia, Elena Koroleva, Kristina Kremenchutckaya, Alexander Gudkov, Anton Buzdin, and Nicolas Borisov. "The Role of the Metabolism of Zinc and Manganese Ions in Human Cancerogenesis." Biomedicines 10, no. 5 (May 5, 2022): 1072. http://dx.doi.org/10.3390/biomedicines10051072.
Повний текст джерелаАнотація:
Metal ion homeostasis is fundamental for life. Specifically, transition metals iron, manganese and zinc play a pivotal role in mitochondrial metabolism and energy generation, anti-oxidation defense, transcriptional regulation and the immune response. The misregulation of expression or mutations in ion carriers and the corresponding changes in Mn2+ and Zn2+ levels suggest that these ions play a pivotal role in cancer progression. Moreover, coordinated changes in Mn2+ and Zn2+ ion carriers have been detected, suggesting that particular mechanisms influenced by both ions might be required for the growth of cancer cells, metastasis and immune evasion. Here, we present a review of zinc and manganese pathophysiology suggesting that these ions might cooperatively regulate cancerogenesis. Zn and Mn effects converge on mitochondria-induced apoptosis, transcriptional regulation and the cGAS-STING signaling pathway, mediating the immune response. Both Zn and Mn influence cancer progression and impact treatment efficacy in animal models and clinical trials. We predict that novel strategies targeting the regulation of both Zn and Mn in cancer will complement current therapeutic strategies.
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Bronold, F. X., and H. Fehske. "Invariant embedding approach to secondary electron emission from metals." Journal of Applied Physics 131, no. 11 (March 21, 2022): 113302. http://dx.doi.org/10.1063/5.0082468.
Повний текст джерелаАнотація:
Based on an invariant embedding principle for the backscattering function, we calculate the electron emission yield for metal surfaces at very low electron impact energies. Solving the embedding equation within a quasi-isotropic approximation and using the effective mass model for the solid experimental data are fairly well reproduced provided (i) incoherent scattering on ion cores is allowed to contribute to the scattering cascades inside the solid and (ii) the transmission through the surface potential takes into account Bragg gaps due to coherent scattering on crystal planes parallel to the surface as well as randomization of the electron’s lateral momentum due to elastic scattering on surface defects. Our results suggest that in order to get secondary electrons out of metals, the large energy loss due to inelastic electron–electron scattering has to be compensated for by incoherent elastic electron–ion core scattering, irrespective of the crystallinity of the sample.
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Martin, Julia E., and David P. Giedroc. "Functional Determinants of Metal Ion Transport and Selectivity in Paralogous Cation Diffusion Facilitator Transporters CzcD and MntE in Streptococcus pneumoniae." Journal of Bacteriology 198, no. 7 (January 19, 2016): 1066–76. http://dx.doi.org/10.1128/jb.00975-15.
Повний текст джерелаАнотація:
ABSTRACTCation diffusion facilitators (CDFs) are a large family of divalent metal transporters that collectively possess broad metal specificity and contribute to intracellular metal homeostasis and virulence in bacterial pathogens.Streptococcus pneumoniaeexpresses two homologous CDF efflux transporters, MntE and CzcD. Cells lackingmntEorczcDare sensitive to manganese (Mn) or zinc (Zn) toxicity, respectively, and specifically accumulate Mn or Zn, respectively, thus suggesting that MntE selectively transports Mn, while CzcD transports Zn. Here, we probe the origin of this metal specificity using a phenotypic growth analysis of pneumococcal variants. Structural homology toEscherichia coliYiiP predicts that both MntE and CzcD are dimeric and each protomer harbors four pairs of conserved metal-binding sites, termed the A site, the B site, and the C1/C2 binuclear site. We find that single amino acid mutations within both the transmembrane domain A site and the B site in both CDFs result in a cellular metal sensitivity similar to that of the corresponding null mutants. However, multiple mutations in the predicted cytoplasmic C1/C2 cluster of MntE have no impact on cellular Mn resistance, in contrast to the analogous substitutions in CzcD, which do have on impact on cellular Zn resistance. Deletion of the MntE-specific C-terminal tail, present only in Mn-specific bacterial CDFs, resulted in only a modest growth phenotype. Further analysis of MntE-CzcD functional chimeric transporters showed that Asn and Asp in theND-DD A-site motif of MntE and the most N-terminal His in theHD-HD site A of CzcD (the specified amino acids are underlined) play key roles in transporter metal selectivity.IMPORTANCECation diffusion facilitator (CDF) proteins are divalent metal ion transporters that are conserved in organisms ranging from bacteria to humans and that play important roles in cellular physiology, from metal homeostasis and resistance to type I diabetes in vertebrates. The respiratory pathogenStreptococcus pneumoniaeexpresses two metal CDF transporters, CzcD and MntE. How CDFs achieve metal selectivity is unclear. We show here that CzcD and MntE are true paralogs, as CzcD transports zinc, while MntE selectively transports manganese. Through the use of an extensive collection of pneumococcal variants, we show that a primary determinant for metal selectivity is the A site within the transmembrane domain. This extends our understanding of how CDFs discriminate among transition metals.
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Partridge, Barry K., James E. Alleman, Patrick J. Fox, and David G. Mast. "Performance Evaluation of Highway Embankment Constructed with Waste Foundry Sand." Transportation Research Record: Journal of the Transportation Research Board 1619, no. 1 (January 1998): 55–63. http://dx.doi.org/10.3141/1619-07.
Повний текст джерелаАнотація:
Considerable savings are possible for the metal casting industry through the development of reuse applications for waste foundry sand (WFS). State departments of transportation face increased pressure to reuse waste materials in transportation construction. In 1996, the Indiana Department of Transportation and Purdue University constructed a demonstration embankment by using WFS from a ferrous foundry. WFS and control embankments were instrumented to monitor geotechnical and environmental performance during and after construction. Stockpile and jobsite WFS samples also were tested. The geotechnical investigation demonstrated that WFS can perform well as a structural fill, having strength and deformation characteristics comparable to natural sand. The compacted WFS has a hydraulic conductivity considerably lower than that of natural sand and generally cannot be considered as freely draining. Environmental testing consisted of Microtox and Nitrotox bioassays, ion chromatography, and inductively coupled plasma testing for metals. Bioassay results indicate the WFS has not leached contaminants at concentrations higher than those expected from natural sand and is not likely to have a negative environmental impact at the site. Ion migration from the WFS into the foundry sand lysimeter was found, supporting bioassay data, but at concentrations below drinking water standards or reuse regulatory criteria. Metal concentrations typically were below detection levels.
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Saga, Koichiro, Shunsuke Kobayashi, and Koji Sueoka. "Quantitative Analysis of Transition Metals Penetrating Silicon Substrate through SiN Film by Dopant Ion Implantation and Annealing." Solid State Phenomena 219 (September 2014): 265–67. http://dx.doi.org/10.4028/www.scientific.net/ssp.219.265.
Повний текст джерелаАнотація:
Metallic contamination on silicon surfaces has a detrimental impact on the performance and yield of ULSI devices. Surface metal impurities degrade the gate oxide integrity while metal impurities dissolved in silicon cause recombination centers and this results in junction leakage. The diffusion behavior of these metal impurities in silicon is well-known [1]. On the other hand, these metal impurities often penetrate the silicon through the silicon oxide or silicon nitride films in ULSI processing. The surface metal impurities penetrate the silicon by colliding with the dopant during ion implantation and are also diffused in silicon by subsequent annealing [2]. While the diffusion behavior of the metal impurities penetrating silicon substrates through the silicon oxide films has been reported [3], little work has been reported on the diffusion behavior of the metal impurities penetrating silicon nitride films. We demonstrated the diffusion behavior of the metal impurities penetrating silicon substrates through a CVD SiN film due to the collision with dopant during ion implantation.