Acceptability of Iron- and Zinc-Biofortified Pearl Millet (ICTP-8203)-Based Complementary Foods among Children in an Urban Slum of Mumbai, India

PubMed Central

Huey, Samantha Lee; Venkatramanan, Sudha; Udipi, Shobha A.; Finkelstein, Julia Leigh; Ghugre, Padmini; Haas, Jere Douglas; Thakker, Varsha; Thorat, Aparna; Salvi, Ashwini; Kurpad, Anura V.; Mehta, Saurabh

2017-01-01

Biofortification, a method for increasing micronutrient content of staple crops, is a promising strategy for combating major global health problems, such as iron and zinc deficiency. We examined the acceptability of recipes prepared using iron- and zinc-biofortified pearl millet (FeZnPM) (~80 ppm Fe, ~34 ppm Zn, varietal ICTP-8203), compared to conventional pearl millet (CPM) (~20 ppm Fe, ~19 ppm Zn) in preparation for an efficacy trial. Our objective was to examine the acceptability of FeZnPM compared to CPM among young children and mothers living in the urban slums of Mumbai. Standardized traditional feeding program recipes (n = 18) were prepared with either FeZnPM or CPM flour. The weight (g) of each food product was measured before and after consumption by children (n = 125) and the average grams consumed over a 3-day period were recorded. Mothers (n = 60) rated recipes using a 9-point hedonic scale. Mean intakes and hedonic scores of each food product were compared using t-tests across the two types of pearl millet. There were no statistically significant differences in consumption by children (FeZnPM: 25.27 ± 13.0 g; CPM: 21.72 ± 6.90 g) across the food products (P = 0.28). Overall mean hedonic scores for all recipes were between 7 to 9 points. CPM products were rated higher overall (8.22 ± 0.28) compared to FeZnPM products (7.95 ± 0.35) (P = 0.01). FeZnPM and CPM were similarly consumed and had high hedonic scores, demonstrating high acceptability in this population. These results support using these varieties of pearl millet in a proposed trial [http://Clinicaltrials.gov ID: NCT02233764; Clinical Trials Registry of India (CTRI), reference number REF/2014/10/007731, CTRI number CTRI/2015/11/006376] testing the efficacy of FeZnPM for improving iron status and growth. PMID:28971097

Fenton-like oxidation of 4-chlorophenol using H2O2 in situ generated by Zn-Fe-CNTs composite.

PubMed

Liu, Yong; Fan, Qing; Liu, Yanlan; Wang, Jianlong

2018-05-15

In this paper, a zinc-iron-carbon nanotubes (Zn-Fe-CNTs) composite was prepared, characterized and used to develop a Fenton-like system of Zn-Fe-CNTs/O 2 for the degradation of 4-chlorophenol (4-CP), in which H 2 O 2 was generated in situ from zinc-carbon galvanic cells and oxygen in aqueous solution was activated by iron attached on the surface of CNTs to produce ·OH radicals for the oxidation of 4-CP. The experimental results showed that the particles of Zn and Fe in Zn-Fe-CNTs composite were adhered to the surface of CNTs, which accelerated the electron transfer process. The BET area of Zn-Fe-CNTs composite was 32.9 m 2 /g. The contents of Zn and Fe (% w) in the composite were 44.7% and 4.2%, respectively. The removal efficiency of 4-CP and TOC in Zn-Fe-CNTs/O 2 system was 90.8% and 52.9%, respectively, with the initial pH of 2.0, O 2 flow rate of 800 mL/min, Zn-Fe-CNTs dosage of 1.0 g/L, 4-CP concentration of 50 mg/L and reaction time of 20 min. Based on the analysis of the degradation intermediate products with LC-MS and IC, a possible degradation pathway of 4-CP in Zn-Fe-CNTs/O 2 system was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Genetic parameters and breeding strategies for high levels of iron and zinc in Phaseolus vulgaris L.

PubMed

Martins, S M; Melo, P G S; Faria, L C; Souza, T L P O; Melo, L C; Pereira, H S

2016-06-10

One of the current focus of common bean breeding programs in Brazil is to increase iron (FeC) and zinc content (ZnC) in grains. The objectives of this study were to estimate genetic parameters for FeC and ZnC in common bean, verify the need for conducting multi-site evaluation tests, identify elite lines that combine high FeC and ZnC with good adaptability, stability, and agronomic potential, and examine the genetic association between FeC and ZnC. Elite lines (140) were evaluated for important agronomic traits in multiple environments. In one trial, FeC and ZnC were evaluated and genetic parameters were estimated. Based on the high heritability estimates and significant selection gains obtained, the conditions for a successful selection was favorable. Of the 140 evaluated lines, 17 had higher FeC and ZnC, and were included in the validation test (2013, five environments), specifically for the evaluation of FeC and ZnC. The line by environment interaction for FeC and ZnC was detected, but it was predominantly simple. The environmental effect strongly influenced FeC and ZnC . The environment Brasília/rainy season was selected as the best evaluation site for preliminary tests for FeC and ZnC, because it resulted in similar conclusions as the mean of the five environments. The lines CNFP 15701 and CNFC 15865 had higher FeC and ZnC and were highly adaptable and stable, and are recommended for utilization in breeding programs. The lines CNFC 15833, CNFC 15703, and CNFP 15676 showed excellent combined agronomic and nutritional traits, and were selected for the development of biofortified cultivars. Additionally, the genetic association between FeC and ZnC was detected.

Development of phosphate rock integrated with iron amendment for simultaneous immobilization of Zn and Cr(VI) in an electroplating contaminated soil.

PubMed

Zhao, Ling; Ding, Zhenliang; Sima, Jingke; Xu, Xiaoyun; Cao, Xinde

2017-09-01

This study aims to develop an amendment for simultaneous immobilization of Zn and Cr(VI) in an abandoned electroplating contaminated soil. Nature phosphate rock was first activated with oxalic acid (O-PR) and then combined with FeSO 4 or zero-valent iron (ZVI) for immobilization of Zn and Cr(VI) from aqueous solutions. Finally, the optimized approach showing the highest immobilization ability in solution was applied in an electroplating contaminated soil. The O-PR combined with FeSO 4 was more effective in simultaneously removing Zn and Cr(VI) than the O-PR integrated with ZVI within the tested solution pH range of 5.5-8.5. Both O-PR with FeSO 4 and with ZVI removed over 95% of Zn from the solution; however, only 42-46% of Cr(VI) was immobilized by O-PR with ZVI, while O-PR with FeSO 4 almost precipitated all Cr(VI). Moreover, there were 75-95% Zn and 95-100% Cr(VI) remaining in the exhausted O-PR with FeSO 4 solid after toxicity characteristic leaching test (TCLP) while the exhausted O-PR with ZVI solid only retained 44-83% Zn and 32-72% Cr(VI). Zinc was immobilized mainly via formation of insoluble Fe-Zn phosphate co-precipitates, while iron-induced reduction of Cr(VI) into stable Cr(OH) 3 or Cr x Fe (1-x) (OH) 3 was responsible for Cr(VI) immobilization. Application of the O-PR integrated with FeSO 4 in the electroplating contaminated soil rapidly reduced the TCLP extractable Zn and Cr(VI) to below the standard limits, with decrease by 50% and 94%, respectively. This study revealed that combination of oxalic acid activated phosphate rock with FeSO 4 could be an effective amendment for remediation of Zn and Cr(VI) contaminated soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing bioavailability levels of metals in effluent-affected rivers: effect of Fe(III) and chelating agents on the distribution of metal speciation.

PubMed

Han, Shuping; Naito, Wataru; Masunaga, Shigeki

To assess the effects of Fe(III) and anthropogenic ligands on the bioavailability of Ni, Cu, Zn, and Pb, concentrations of bioavailable metals were measured by the DGT (diffusive gradients in thin films) method in some urban rivers, and were compared with concentrations calculated by a chemical equilibrium model (WHAM 7.0). Assuming that dissolved Fe(III) (<0.45 μm membrane filtered) was in equilibrium with colloidal iron oxide, the WHAM 7.0 model estimated that bioavailable concentrations of Ni, Cu, and Zn were slightly higher than the corresponding values estimated assuming that dissolved Fe(III) was absent. In contrast, lower levels of free Pb were predicted by the WHAM 7.0 model when dissolved Fe(III) was included. Estimates showed that most of the dissolved Pb was present as colloidal iron-Pb complex. Ethylene-diamine-tetra-acetic acid (EDTA) concentrations at sampling sites were predicted from the relationship between EDTA and the calculated bioavailable concentration of Zn. When both colloidal iron and predicted EDTA concentrations were included in the WHAM 7.0 calculations, dissolved metals showed a strong tendency to form EDTA complexes, in the order Ni > Cu > Zn > Pb. With the inclusion of EDTA, bioavailable concentrations of Ni, Cu, and Zn predicted by WHAM 7.0 were different from those predicted considering only humic substances and colloidal iron.

Crop acquisition of phosphorus, iron and zinc from soil in cereal/legume intercropping systems: a critical review

PubMed Central

Xue, Yanfang; Xia, Haiyong; Christie, Peter; Zhang, Zheng; Li, Long; Tang, Caixian

2016-01-01

Background Phosphorus (P), iron (Fe) and zinc (Zn) are essential elements for plant growth and development, but their availability in soil is often limited. Intercropping contributes to increased P, Fe and Zn uptake and thereby increases yield and improves grain nutritional quality and ultimately human health. A better understanding of how intercropping leads to increased plant P, Fe and Zn availability will help to improve P-fertilizer-use efficiency and agronomic Fe and Zn biofortification. Scope This review synthesizes the literature on how intercropping of legumes with cereals increases acquisition of P, Fe and Zn from soil and recapitulates what is known about root-to-shoot nutrient translocation, plant-internal nutrient remobilization and allocation to grains. Conclusions Direct interspecific facilitation in intercropping involves below-ground processes in which cereals increase Fe and Zn bioavailability while companion legumes benefit. This has been demonstrated and verified using isotopic nutrient tracing and molecular analysis. The same methodological approaches and field studies should be used to explore direct interspecific P facilitation. Both niche complementarity and interspecific facilitation contribute to increased P acquisition in intercropping. Niche complementarity may also contribute to increased Fe and Zn acquisition, an aspect poorly understood. Interspecific mobilization and uptake facilitation of sparingly soluble P, Fe and Zn from soil, however, are not the only determinants of the concentrations of P, Fe and Zn in grains. Grain yield and nutrient translocation from roots to shoots further influence the concentrations of these nutrients in grains. PMID:26749590

Removal of metals from landfill leachate by sorption to activated carbon, bone meal and iron fines.

PubMed

Modin, Hanna; Persson, Kenneth M; Andersson, Anna; van Praagh, Martijn

2011-05-30

Sorption filters based on granular activated carbon, bone meal and iron fines were tested for their efficiency of removing metals from landfill leachate. Removal of Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sr and Zn were studied in a laboratory scale setup. Activated carbon removed more than 90% of Co, Cr, Cu, Fe, Mn and Ni. Ca, Pb, Sr and Zn were removed but less efficiently. Bone meal removed over 80% of Cr, Fe, Hg, Mn and Sr and 20-80% of Al, Ca, Cu, Mo, Ni, Pb and Zn. Iron fines removed most metals (As, Ca, Co, Cr, Cu, Fe, Mg, Mn, Pb, Sr and Zn) to some extent but less efficiently. All materials released unwanted substances (metals, TOC or nutrients), highlighting the need to study the uptake and release of a large number of compounds, not only the target metals. To remove a wide range of metals using these materials two or more filter materials may need to be combined. Sorption mechanisms for all materials include ion exchange, sorption and precipitation. For iron fines oxidation of Fe(0) seems to be important for metal immobilisation. Copyright © 2011 Elsevier B.V. All rights reserved.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels1[OPEN

PubMed Central

2017-01-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis (Arabidopsis thaliana) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. PMID:28500270

The assessment of soil availability and wheat grain status of zinc and iron in Serbia: Implications for human nutrition.

PubMed

Nikolic, Miroslav; Nikolic, Nina; Kostic, Ljiljana; Pavlovic, Jelena; Bosnic, Predrag; Stevic, Nenad; Savic, Jasna; Hristov, Nikola

2016-05-15

The deficiency of zinc (Zn) and iron (Fe) is a global issue causing not only considerable yield losses of food crops but also serious health problems. We have analysed Zn and Fe concentrations in the grains of two bread wheat cultivars along native gradient of micronutrient availability throughout Serbia. Although only 13% of the soil samples were Zn deficient and none was Fe deficient, the levels of these micronutrients in grain were rather low (median values of 21 mg kg(-1) for Zn and 36 mg kg(-1) for Fe), and even less adequate in white flour. Moreover, excessive P fertilization of calcareous soils in the major wheat growing areas strongly correlated with lower grain concentration of Zn. Our results imply that a latent Zn deficiency in wheat grain poses a high risk for grain quality relevant to human health in Serbia, where wheat bread is a staple food. Copyright © 2016 Elsevier B.V. All rights reserved.

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

USDA-ARS?s Scientific Manuscript database

Iron (Fe) and zinc (Zn) deficiencies are the most prevalent micronutrient malnutrition globally1. Fe in rice has proven efficacious in improving serum ferritin concentration and body Fe levels2. Rapid progress in biofortification demonstrates the feasibility to enhance Fe in polished rice by expre...

Synchrotron study of metal localization in Typha latifolia L. root sections

DOE PAGES

Qian, Yu; Jones, Keith W.; Feng, Huan; ...

2015-09-15

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues of Typha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution ofmore » Pb and Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p < 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. Furthermore, the Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.« less

Changing the zinc:iron ratio in a cereal-based nutritional supplement has no effect on percent absorption of iron and zinc in Sri Lankan children

USDA-ARS?s Scientific Manuscript database

The Thriposha program is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein, and micronutrients as a 'ready-to-eat' cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn: Fe in orde...

Removal of Fe3+ and Zn2+ from plasma metalloproteins by iron chelating therapeutics depicted with SEC-ICP-AES.

PubMed

Sooriyaarachchi, Melani; Gailer, Jürgen

2010-08-28

The iron chelation therapy drugs desferrioxamine B (DFO) and deferiprone (DFP) are used to treat iron overload patients, but not much is known about their adverse effects on other essential metals in vivo. After the addition of a clinically relevant dose of DFP or an equimolar dose of DFO to human plasma in vitro, the mixtures were analyzed by size exclusion chromatography (SEC) coupled to an inductively coupled plasma atomic emission spectrometer (ICP-AES). Simultaneous detection of the emission lines of copper, iron and zinc allowed the visualization of changes that these drugs exerted at the metalloprotein level. After the addition of DFP, a <10 kDa novel Fe-peak was detected and identified as (DFP)(3)Fe, whereas DFO resulted in the elution of a much smaller amount of Fe in this elution range. In fact, DFP was approximately 8-times more efficient than DFO regarding the removal of Fe from plasma proteins. The addition of both iron chelators also resulted in the elution of a <10 kDa novel Zn-peak. DFP abstracted twice as much Zn from plasma proteins compared to DFO. The identification of one of these peaks as (DFP)(2)Zn establishes a feasible biomolecular basis for the etiology of Zn-deficiency in patients that undergo long-term treatment with these drugs. Our results demonstrate that the analysis of plasma by SEC-ICP-AES can simultaneously provide insight into the efficacy of chelation therapy drugs and their adverse health effects at the metalloprotein level. Thus, SEC-ICP-AES emerges as a useful analytical tool to visualize health-relevant bioinorganic chemistry-related reactions of medicinal drugs in blood plasma in vitro.

Iron Sulfide Attenuates the Methanogenic Toxicity of Elemental Copper and Zinc Oxide Nanoparticles and their Soluble Metal Ion Analogs

PubMed Central

Gonzalez-Estrella, Jorge; Gallagher, Sara; Sierra-Alvarez, Reyes; Field, Jim A.

2016-01-01

Elemental copper (Cu0) and zinc oxide (ZnO) nanoparticle (NP) toxicity to methanogens has been attributed to the release of soluble metal ions. Iron sulfide (FeS) partially controls the soluble concentration of heavy metals and their toxicity in aquatic environments. Heavy metals displace the Fe from FeS forming poorly soluble metal sulfides in the FeS matrix. Therefore, FeS may be expected to attenuate the NP toxicity. This work assessed FeS as an attenuator of the methanogenic toxicity of Cu0 and ZnO NPs and their soluble salt analogs. The toxicity attenuation capacity of fine (25–75 µm) and coarse (500 to 1200 µm) preparations of FeS (FeS-f and FeS-c respectively) was tested in the presence of highly inhibitory concentrations of CuCl2, ZnCl2 Cu0 and ZnO NPs. FeS-f attenuated methanogenic toxicity better than FeS-c. The results revealed that 2.5× less FeS-f than FeS-c was required to recover the methanogenic activity to 50% (activity normalized to uninhibited controls). The results also indicated that a molar FeS-f/Cu0 NP, FeS-f/ZnO NP, FeS-f/ZnCl2, and FeS-f/CuCl2 ratio of 2.14, 2.14, 4.28, and 8.56 respectively, was necessary to recover the methanogenic activity to >75%. Displacement experiments demonstrated that CuCl2 and ZnCl2 partially displaced Fe from FeS. As a whole, the results indicate that not all the sulfide in FeS was readily available to react with the soluble Cu and Zn ions which may explain the need for a large stoichiometric excesses of FeS to highly attenuate Cu and Zn toxicity. Overall, this study provides evidence that FeS attenuates the toxicity caused by Cu0 and ZnO NPs and their soluble ion analogs to methanogens. PMID:26803736

Understanding the role of iron in the magnetism of Fe doped ZnO nanoparticles.

PubMed

Beltrán, J J; Barrero, C A; Punnoose, A

2015-06-21

The actual role of transition metals like iron in the room temperature ferromagnetism (RTFM) of Fe doped ZnO nanoparticles is still an unsolved problem. While some studies concluded that the Fe ions participate in the magnetic interaction, others in contrast do not believe Fe to play a direct role in the magnetic exchange interaction. To contribute to the understanding of this issue, we have carefully investigated the structural, optical, vibrational and magnetic properties of sol-gel synthesized Zn1-xFexO (0 < x < 0.10) nanoparticles. No Fe(2+) was detected in any sample. We found that high spin Fe(3+) ions are substitutionally incorporated at the Zn(2+) in the tetrahedral-core sites and in pseudo-octahedral surface sites in ZnO. Superficial OH(-) was observed in all samples. For x ≤ 0.03, an increment in Fe doping concentration decreased a and c lattice parameters, average Zn-O bond length, average crystallite size and band gap; while it increased the degree of distortion and quadrupole splitting. Undoped ZnO nanoparticles exhibited very weak RTFM with a saturation magnetization (Ms) of ∼0.47 memu g(-1) and this value increased to ∼2.1 memu g(-1) for Zn0.99Fe0.01O. Very interestingly, the Ms for Zn0.99Fe0.01O and Zn0.97Fe0.03O increased by a factor of about ∼2.3 by increasing annealing for 1 h to 3 h. For x ≥ 0.05, ferrimagnetic disordered spinel ZnFe2O4 was formed and this phase was found to become more ordered with increasing annealing time. Fe does not contribute directly to the RTFM, but its presence promoted the formation of additional single charged oxygen vacancies, zinc vacancies, and more oxygen-ended polar terminations at the nanoparticle surface. These defects, which are mainly superficial, altered the electronic structure and are considered as the main sources of the observed ferromagnetism.

Heavy Metals Induce Iron Deficiency Responses at Different Hierarchic and Regulatory Levels.

PubMed

Lešková, Alexandra; Giehl, Ricardo F H; Hartmann, Anja; Fargašová, Agáta; von Wirén, Nicolaus

2017-07-01

In plants, the excess of several heavy metals mimics iron (Fe) deficiency-induced chlorosis, indicating a disturbance in Fe homeostasis. To examine the level at which heavy metals interfere with Fe deficiency responses, we carried out an in-depth characterization of Fe-related physiological, regulatory, and morphological responses in Arabidopsis ( Arabidopsis thaliana ) exposed to heavy metals. Enhanced zinc (Zn) uptake closely mimicked Fe deficiency by leading to low chlorophyll but high ferric-chelate reductase activity and coumarin release. These responses were not caused by Zn-inhibited Fe uptake via IRON-REGULATED TRANSPORTER (IRT1). Instead, Zn simulated the transcriptional response of typical Fe-regulated genes, indicating that Zn affects Fe homeostasis at the level of Fe sensing. Excess supplies of cobalt and nickel altered root traits in a different way from Fe deficiency, inducing only transient Fe deficiency responses, which were characterized by a lack of induction of the ethylene pathway. Cadmium showed a rather inconsistent influence on Fe deficiency responses at multiple levels. By contrast, manganese evoked weak Fe deficiency responses in wild-type plants but strongly exacerbated chlorosis in irt1 plants, indicating that manganese antagonized Fe mainly at the level of transport. These results show that the investigated heavy metals modulate Fe deficiency responses at different hierarchic and regulatory levels and that the interaction of metals with physiological and morphological Fe deficiency responses is uncoupled. Thus, this study not only emphasizes the importance of assessing heavy metal toxicities at multiple levels but also provides a new perspective on how Fe deficiency contributes to the toxic action of individual heavy metals. © 2017 American Society of Plant Biologists. All Rights Reserved.

Ultrasmall water-soluble metal-iron oxide nanoparticles as T1-weighted contrast agents for magnetic resonance imaging.

PubMed

Zeng, Leyong; Ren, Wenzhi; Zheng, Jianjun; Cui, Ping; Wu, Aiguo

2012-02-28

Using an improved hydrolysis method of inorganic salts assisted with water-bath incubation, ultrasmall water-soluble metal-iron oxide nanoparticles (including Fe(3)O(4), ZnFe(2)O(4) and NiFe(2)O(4) nanoparticles) were synthesized in aqueous solutions, which were used as T(1)-weighted contrast agents for magnetic resonance imaging (MRI). The morphology, structure, MRI relaxation properties and cytotoxicity of the as-prepared metal-iron oxide nanoparticles were characterized, respectively. The results showed that the average sizes of nanoparticles were about 4 nm, 4 nm and 5 nm for Fe(3)O(4), ZnFe(2)O(4) and NiFe(2)O(4) nanoparticles, respectively. Moreover, the nanoparticles have good water dispersibility and low cytotoxicity. The MRI test showed the strong T(1)-weighted, but the weak T(2)-weighted MRI performance of metal-iron oxide nanoparticles. The high T(1)-weighted MRI performance can be attributed to the ultrasmall size of metal-iron oxide nanoparticles. Therefore, the as-prepared metal-iron oxide nanoparticles with good water dispersibility and ultrasmall size can have potential applications as T(1)-weighted contrast agent materials for MRI.

Decreased Dissolution of ZnO by Iron Doping Yields Nanoparticles with Reduced Toxicity in the Rodent Lung and Zebrafish Embryos

PubMed Central

Xia, Tian; Zhao, Yan; Sager, Tina; George, Saji; Pokhrel, Suman; Li, Ning; Schoenfeld, David; Meng, Huan; Lin, Sijie; Wang, Xiang; Wang, Meiying; Ji, Zhaoxia; Zink, Jeffrey I.; Mädler, Lutz; Castranova, Vincent; Lin, Shuo; Nel, Andre E.

2014-01-01

We have recently shown that the dissolution of ZnO nanoparticles and Zn2+ shedding leads to a series of sub-lethal and lethal toxicological responses at cellular level that can be alleviated by iron-doping. Iron-doping changes the particle matrix and slows the rate of particle dissolution. To determine whether iron doping of ZnO also leads to lesser toxic effects in vivo, toxicity studies were performed in rodent and zebrafish models. First, we synthesized a fresh batch of ZnO nanoparticles doped with 1–10 wt % of Fe. These particles were extensively characterized to confirm their doping status, reduced rate of dissolution in an exposure medium and reduced toxicity in a cellular screen. Subsequent studies compared the effects of undoped to doped particles in the rat lung, mouse lung and the zebrafish embryo. The zebrafish studies looked at embryo hatching and mortality rates as well as the generation of morphological defects, while the endpoints in the rodent lung included an assessment of inflammatory cell infiltrates, LDH release and cytokine levels in the bronchoalveolar lavage fluid. Iron doping, similar to the effect of the metal chelator, DTPA, interfered in the inhibitory effects of Zn2+ on zebrafish hatching. In the oropharyngeal aspiration model in the mouse, iron doping was associated with decreased polymorphonuclear cell counts and IL-6 mRNA production. Doped particles also elicited decreased heme oxygenase 1 expression in the murine lung. In the intratracheal instillation studies in the rat, Fe-doping was associated with decreased polymorphonuclear cell counts, LDH and albumin levels. All considered, the above data show that Fe-doping is a possible safe design strategy for preventing ZnO toxicity in animals and the environment. PMID:21250651

Controllable synthesis, magnetic properties, and enhanced photocatalytic activity of spindlelike mesoporous α-Fe(2)O(3)/ZnO core-shell heterostructures.

PubMed

Wu, Wei; Zhang, Shaofeng; Xiao, Xiangheng; Zhou, Juan; Ren, Feng; Sun, Lingling; Jiang, Changzhong

2012-07-25

Mesoporous spindlelike iron oxide/ZnO core-shell heterostructures are successfully fabricated by a low-cost, surfactant-free, and environmentally friendly seed-mediate strategy with the help of postannealing treatment. The material composition and stoichiometry, as well as these magnetic and optical properties, have been examined and verified by means of high-resolution transmission electron microscopy and X-ray diffraction, the thickness of ZnO layer can be simply tailored by the concentration of zinc precursor. Considering that both α-Fe2O3 and ZnO are good photocatalytic materials, we have investigated the photodegradation performances of the core-shell heterostructures using organic dyes Rhodamin B (RhB). It is interesting to find that the as-obtained iron oxides/ZnO core-shell heterostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to the as-used α-Fe2O3 seeds and commercial TiO2 products (P25), mainly owing to the synergistic effect between the narrow and wide bandgap semiconductors and effective electron-hole separation at the interfaces of iron oxides/ZnO.

Synchrotron study of metal localization in Typha latifolia  L. root sections

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

Qian, Yu; Feng, Huan; Gallagher, Frank J.

2015-10-13

Understanding mechanisms that control plant root metal assimilation in soil is critical to the sustainable management of metal-contaminated land. With the assistance of the synchrotron X-ray fluorescence technique, this study investigated possible mechanisms that control the localization of Fe, Cu, Mn, Pb and Zn in the root tissues ofTypha latifolia L. collected from a contaminated wetland. Metal localizations especially in the case of Fe and Pb in the dermal tissue and the vascular bundles were different. Cluster analysis was performed to divide the dermal tissue into iron-plaque-enriched dermal tissue and regular dermal tissue based on the spatial distribution of Pb andmore » Fe. Factor analysis showed that Cu and Zn were closely correlated to each other in the dermal tissues. The association of Cu, Zn and Mn with Fe was strong in both regular dermal tissue and iron-plaque-enriched dermal tissue, while significant (p< 0.05) correlation of Fe with Pb was only observed in tissues enriched with iron plaque. In the vascular bundles, Zn, Mn and Cu showed strong association, suggesting that the localization of these three elements was controlled by a similar mechanism. Iron plaque in the peripheral dermal tissues acted as a barrier for Pb and a buffer for Zn, Cu and Mn. The Casparian strip regulated the transportation of metals from dermal tissues to the vascular bundles. The results suggested that the mechanisms controlling metal localization in root tissues varied with both tissue types and metals.« less

Formation of the ZnFe2O4 phase in an electric arc furnace off-gas treatment system.

PubMed

Suetens, T; Guo, M; Van Acker, K; Blanpain, B

2015-04-28

To better understand the phenomena of ZnFe2O4 spinel formation in electric arc furnace dust, the dust was characterized with particle size analysis, X-ray fluorescence (XRF), electron backscatter diffraction (EBSD), and electron probe micro-analysis (EPMA). Different ZnFe2O4 formation reaction extents were observed for iron oxide particles with different particle sizes. ZnO particles were present as both individual particles and aggregated on the surface of larger particles. Also, the slag particles found in the off-gas were shown not to react with the zinc vapor. After confirming the presence of a ZnFe2O4 formation reaction, the thermodynamic feasibility of in-process separation - a new electric arc furnace dust treatment technology - was reevaluated. The large air intake and the presence of iron oxide particles in the off-gas were included into the thermodynamic calculations. The formation of the stable ZnFe2O4 spinel phase was shown to be thermodynamically favorable in current electric arc furnace off-gas ducts conditions even before reaching the post combustion chamber. Copyright © 2015 Elsevier B.V. All rights reserved.

Different copolymer films on ZnFeCo particles: Synthesis and anticorrosion properties

NASA Astrophysics Data System (ADS)

Ozyilmaz, A. Tuncay; Avsar, Busra; Ozyilmaz, Gul; Karahan, İ. Hakkı; Camurcu, Taskin; Colak, Fatma

2014-11-01

Zinc-iron-cobalt (ZnFeCo) particles were electrochemically deposited on carbon steel (CS) electrode applying current of 3 mA with chronopotentiometry technique. ZnFeCo particles had homogenous, smooth with prismatic structure. It was shown that the ZnFeCo particles exhibited important barrier effect on CS substrate. Poly(aniline-co-o-anisidine), poly(aniline-co-pyrrole), poly(aniline-co-N-methylpyrrole) and poly(o-anisidine-co-pyrrole) copolymer films were obtained on CS/ZnFeCo electrode. Evaluation of anticorrosion performance of copolymer coatings in 3.5% NaCl solution was investigated by using AC impedance spectroscopy (EIS) technique, anodic polarization and the Eocp-time curves. Copolymer films exhibited significant physical barrier behavior on ZnFeCo plated carbon steel, in longer exposure time.

Inversion domain boundaries in ZnO with additions of Fe2O3 studied by high-resolution ADF imaging.

PubMed

Wolf, Frank; Freitag, Bert H; Mader, Werner

2007-01-01

Columns of metal atoms in the polytypoid compound Fe2O3(ZnO)15 could be resolved by high angle annular dark field imaging in a transmission electron microscopy (TEM)/STEM electron microscope--a result which could not be realized by high-resolution bright field imaging due to inherent strain from inversion domains and inversion domain boundaries (IDBs) in the crystals. The basal plane IDB was imaged in [11 00] yielding the spacing of the two adjacent ZnO domains, while imaging in [21 1 0] yields the position of single metal ions. The images allow the construction of the entire domain structure including the stacking sequence and positions of the oxygen ions. The IDB consists of a single layer of octahedrally co-ordinated Fe3+ ions, and the inverted ZnO domains are related by point symmetry at the iron position. The FeO6 octahedrons are compressed along the ZnO c-axis resulting in a FeO bond length of 0.208 nm which is in the range of FeO distances in iron containing oxides. The model of the basal plane boundary resembles that of the IDB in polytypoid ZnO-In2O3 compounds.

Effect of MgO on Liquidus Temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2-MgO System in Equilibrium with Metallic Iron

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-06-01

The phase equilibria in the ZnO-"FeO"-Al2O3-CaO-SiO2-MgO system have been determined experimentally in equilibrium with metallic iron. Synthetic slags were equilibrated at a high temperature, quenched, and then the compositions of the phases in equilibrium were measured using electron probe X-ray microanalysis. Pseudoternary sections of the form ZnO-"FeO"-(Al2O3 + CaO + SiO2) for CaO/SiO2 = 0.71, (CaO + SiO2)/Al2O3 = 5 and fixed MgO concentrations of 2, 4, and 6 wt pct have been constructed. Wustite (Fe2+,Mg,Zn)O and spinel (Fe2+,Mg,Zn)O·(Al,Fe3+)2O3 are the major primary phases in the temperature and composition ranges investigated. The liquidus temperatures are increased by 140 K in the wustite primary phase field and by 70 K in the spinel primary phase field with the addition of 6 wt pct MgO in the slag. The partitioning of MgO and ZnO between the solid and liquid phases has been discussed.

Removal of As, Mn, Mo, Se, U, V and Zn from groundwater by zero-valent iron in a passive treatment cell: reaction progress modeling.

PubMed

Morrison, Stan J; Metzler, Donald R; Dwyer, Brian P

2002-05-01

Three treatment cells were operated at a site near Durango, CO. One treatment cell operated for more than 3 years. The treatment cells were used for passive removal of contamination from groundwater at a uranium mill tailings repository site. Zero-valent iron [Fe(0)] that had been powdered, bound with aluminosilicate and molded into plates was used as a reactive material in one treatment cell. The others used granular Fe(0) and steel wool. The treatment cells significantly reduced concentrations of As, Mn, Mo, Se, U, V and Zn in groundwater that flowed through it. Zero-valent iron [Fe(0)], magnetite (Fe3O4), calcite (CaCO3), goethite (FeOOH) and mixtures of contaminant-bearing phases were identified in the solid fraction of one treatment cell. A reaction progress approach was used to model chemical evolution of water chemistry as it reacted with the Fe(0). Precipitation of calcite, ferrous hydroxide [Fe(OH)2] and ferrous sulfide (FeS) were used to simulate observed changes in major-ion aqueous chemistry. The amount of reaction progress differed for each treatment cell. Changes in contaminant concentrations were consistent with precipitation of reduced oxides (UO2, V2O3), sulfides (As2S3, ZnS), iron minerals (FeSe2, FeMoO4) and carbonate (MnCO3). Formation of a free gas phase and precipitation of minerals contributed to loss of hydraulic conductivity in one treatment cell.

Iron-[S,S']-EDDS (FeEDDS) Chelate as an Iron Source for Horticultural Crop Production: Marigold Growth and Nutrition, Spectral Properties, and Photodegradation

USDA-ARS?s Scientific Manuscript database

Aminopolycarboxylic acid (APCA) complexones, commonly referred to as ligands or chelating agents, like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to p...

Binding of the Zn2+ ion to ferric uptake regulation protein from E. coli and the competition with Fe2+ binding: a molecular modeling study of the effect on DNA binding and conformational changes of Fur

NASA Astrophysics Data System (ADS)

Jabour, Salih; Hamed, Mazen Y.

2009-04-01

The three dimensional structure of Ferric uptake regulation protein dimer from E. coli, determined by molecular modeling, was docked on a DNA fragment (iron box) and Zn2+ ions were added in two steps. The first step involved the binding of one Zn2+ ion to what is known as the zinc site which consists of the residues Cys 92, Cys 95, Asp 137, Asp141, Arg139, Glu 140, His 145 and His 143 with an average metal-Nitrogen distance of 2.5 Å and metal-oxygen distance of 3.1-3.2 Å. The second Zn2+ ion is bound to the iron activating site formed from the residues Ile 50, His 71, Asn 72, Gly 97, Asp 105 and Ala 109. The binding of the second Zn2+ ion strengthened the binding of the first ion as indicated by the shortening of the zinc-residue distances. Fe2+, when added to the complex consisting of 2Zn2+/Fur dimer/DNA, replaced the Zn2+ ion in the zinc site and when a second Fe2+ was added, it replaced the second zinc ion in the iron activating site. The binding of both zinc and iron ions induced a similar change in Fur conformations, but shifted residues closer to DNA in a different manner. This is discussed along with a possible role for the Zn2+ ion in the Fur dimer binding of DNA in its repressor activity.

Mapping Grain Iron and Zinc Content Quantitative Trait Loci in an Iniadi-Derived Immortal Population of Pearl Millet

PubMed Central

Kumar, Sushil; Hash, Charles Tom; Nepolean, Thirunavukkarasu; Mahendrakar, Mahesh D.; Satyavathi, Chellapilla Tara; Singh, Govind; Rathore, Abhishek; Gupta, Rajeev; Srivastava, Rakesh K.

2018-01-01

Pearl millet is a climate-resilient nutritious crop requiring low inputs and is capable of giving economic returns in marginal agro-ecologies. In this study, we report large-effect iron (Fe) and zinc (Zn) content quantitative trait loci (QTLs) using diversity array technology (DArT) and simple sequence repeats (SSRs) markers to generate a genetic linkage map using 317 recombinant inbred line (RIL) population derived from the (ICMS 8511-S1-17-2-1-1-B-P03 × AIMP 92901-S1-183-2-2-B-08) cross. The base map [seven linkage groups (LGs)] of 196 loci was 964.2 cM in length (Haldane). AIMP 92901-S1-183-2-2-B-08 is an Iniadi line with high grain Fe and Zn, tracing its origin to the Togolese Republic, West Africa. The content of grain Fe in the RIL population ranged between 20 and 131 ppm (parts per million), and that of Zn from 18 to 110 ppm. QTL analysis revealed a large number of QTLs for high grain iron (Fe) and zinc (Zn) content. A total of 19 QTLs for Fe and Zn were detected, of which 11 were for Fe and eight were for Zn. The portion of the observed phenotypic variance explained by different QTLs for grain Fe and Zn content varied from 9.0 to 31.9% (cumulative 74%) and from 9.4 to 30.4% (cumulative 65%), respectively. Three large-effect QTLs for both minerals were co-mapped in this population, one on LG1 and two on LG7. The favorable QTL alleles of both mineral micronutrients were contributed by the male parent (AIMP 92901-deriv-08). Three putative epistasis interactions were observed for Fe content, while a single digenic interaction was found for Zn content. The reported QTLs may be useful in marker-assisted selection (MAS) programs, in genomic selection (GS) breeding pipelines for seed and restorer parents, and in population improvement programs for pearl millet. PMID:29751669

Mapping Grain Iron and Zinc Content Quantitative Trait Loci in an Iniadi-Derived Immortal Population of Pearl Millet.

PubMed

Kumar, Sushil; Hash, Charles Tom; Nepolean, Thirunavukkarasu; Mahendrakar, Mahesh D; Satyavathi, Chellapilla Tara; Singh, Govind; Rathore, Abhishek; Yadav, Rattan S; Gupta, Rajeev; Srivastava, Rakesh K

2018-05-11

Pearl millet is a climate-resilient nutritious crop requiring low inputs and is capable of giving economic returns in marginal agro-ecologies. In this study, we report large-effect iron (Fe) and zinc (Zn) content quantitative trait loci ( QTLs) using diversity array technology (DArT) and simple sequence repeats (SSRs) markers to generate a genetic linkage map using 317 recombinant inbred line (RIL) population derived from the (ICMS 8511-S1-17-2-1-1-B-P03 × AIMP 92901-S1-183-2-2-B-08) cross. The base map [seven linkage groups (LGs)] of 196 loci was 964.2 cM in length (Haldane). AIMP 92901-S1-183-2-2-B-08 is an Iniadi line with high grain Fe and Zn, tracing its origin to the Togolese Republic, West Africa. The content of grain Fe in the RIL population ranged between 20 and 131 ppm (parts per million), and that of Zn from 18 to 110 ppm. QTL analysis revealed a large number of QTLs for high grain iron (Fe) and zinc (Zn) content. A total of 19 QTLs for Fe and Zn were detected, of which 11 were for Fe and eight were for Zn. The portion of the observed phenotypic variance explained by different QTLs for grain Fe and Zn content varied from 9.0 to 31.9% (cumulative 74%) and from 9.4 to 30.4% (cumulative 65%), respectively. Three large-effect QTLs for both minerals were co-mapped in this population, one on LG1 and two on LG7. The favorable QTL alleles of both mineral micronutrients were contributed by the male parent (AIMP 92901-deriv-08). Three putative epistasis interactions were observed for Fe content, while a single digenic interaction was found for Zn content. The reported QTLs may be useful in marker-assisted selection (MAS) programs, in genomic selection (GS) breeding pipelines for seed and restorer parents, and in population improvement programs for pearl millet.

Different Phosphorus Supplies Altered the Accumulations and Quantitative Distributions of Phytic Acid, Zinc, and Iron in Rice (Oryza sativa L.) Grains.

PubMed

Su, Da; Zhou, Lujian; Zhao, Qian; Pan, Gang; Cheng, Fangmin

2018-02-21

Development of rice cultivars with low phytic acid (lpa) is considered as a primary strategy for biofortification of zinc (Zn) and iron (Fe). Here, two rice genotypes (XS110 and its lpa mutant) were used to investigate the effect of P supplies on accumulations and distributions of PA, Zn, and Fe in rice grains by using hydroponics and detached panicle culture system. Results showed that higher P level increased grain PA concentration on dry matter basis (g/kg), but it markedly decreased PA accumulation on per grain basis (mg/grain). Meanwhile, more P supply reduced the amounts and bioavailabilities of Zn and Fe both in milled grains and in brown grains. Comparatively, lpa mutant was more susceptive to exogenous P supply than its wild type. Hence, the appropriate P fertilizer application should be highlighted in order to increase grain microelement (Zn and Fe) contents and improve nutritional quality in rice grains.

Mobility and fractionation of Fe, Pb and Zn in river sediments from a silver and base-metals mining area: Taxco, México.

PubMed

Espinosa, E; Armienta, M A

2007-08-01

The impact of mining wastes on both the concentration and environmental mobility of Zn, Pb and Fe was studied in a shallow river. The studied tributary of the Taxco river is located south of the historical Ag, Zn, Cu and Pb mining area of Taxco, about 150 km south of México City. Methodology included total concentration determinations and sequential extraction analyses of the operational defined fractions of sediments. Results indicated that Fe, Pb and Zn concentrations are up to 5, 100 and 390 times respectively, greater than regional background concentrations. Higher contents of Pb and Zn were observed in the rainy season versus the dry season, whereas Fe was lower in the rainy season. Zinc and lead increased downflow in the dry season, and did not show any trend during the rainy season. Speciation showed that Zn was mainly linked to the carbonatic fraction (25-39%), to the hydrous Fe/Mn oxides fraction (15-25%) and to the organic matter and sulfide fraction (14-48%); lead was mainly associated to the hydrous Fe/Mn oxides (49-59%) and residual (22-39%) fractions; finally, iron was contained mainly in the residual (65-78%) and the hydrous Fe/Mn oxides fraction (15%). Mobility decreased according to the relation: Zn > Pb > Fe. Sediments were classified as strongly polluted in zinc, strongly to very strongly polluted in Pb, and moderately to strongly polluted in iron. However, a low proportion of metals in the exchangeable fractions, indicates low bioavailability. Limestone presence played a very important role on Zn and Pb fractionation and environmental mobility. Results show the importance of including geological background in river pollution studies.

Iron and zinc fortification of corn tortilla made either at the household or at industrial scale.

PubMed

Tovar, Luis Raul; Larios-Saldaña, Alfredo

2005-03-01

Fe and Zn deficiencies among the Mexican population are widespread, and one-third of children and women of childbearing age are anemic. Since diets that are Fe-deficient are most probably also Zn-deficient, a proprietary process was developed to fortify corn tortilla with these trace elements at the first stage of treatment with lime. Phytic acid (PA), Ca, Fe, and Zn content were determined, as well as the molar ratios of phytate/Fe, phytate/Zn, and Ca x phytate to Zn in traditional and fortified tortillas; the Student's t-test was used to detect differences between the treatments (p < 0.001). Contents of Fe and Zn in the fortified tortilla relative to the traditional tortilla were 1.9 and 3.4 times greater than the latter, whereas PA contents showed the opposite result, i.e. traditional tortillas had 1.65 times more PA than the fortified tortilla. Consequently the calculated molar ratios were statistically more favorable for fortified than for traditional tortillas (p < 0.001). The process developed allows making iron- and zinc-fortified tortillas by lime-treating or nixtamalizing corn either at the household, at small-scale tortilla shops, or at industrial scale by using lime fortified with both trace elements. The cost of this fortification is negligible.

Effect of Sulfur on Liquidus Temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2-S System in Equilibrium with Metallic Iron

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-10-01

The phase equilibria in the ZnO-"FeO"-Al2O3-CaO-SiO2-S system have been determined experimentally in equilibrium with metallic iron. A pseudoternary section of the form ZnO-"FeO"-(Al2O3+CaO+SiO2) for CaO/SiO2 = 0.71 (weight), (CaO+SiO2)/Al2O3 = 5.0 (weight), and fixed 2.0 wt pct S concentration has been constructed. It was found that the addition of 2.0 wt pct S to the liquid extends the spinel primary phase field significantly and decreases the size of the wustite primary phase field. The liquidus temperature in the wustite primary phase field is decreased by approximately 80 K and the liquidus temperature in the spinel primary phase field is decreased by approximately 10 K with addition of 2.0 wt pct S in the composition range investigated. It was also found that iron-zinc sulfides are present in some samples in the spinel primary phase field, which are matte appearing at low zinc concentrations and sphalerite (Zn,Fe)S at higher zinc concentrations. The presence of sulfur in the slag has a minor effect on the partitioning of ZnO between the wustite and liquid phases but no effect on the partitioning of ZnO between the spinel and liquid phases.

Improving the selective cancer killing ability of ZnO nanoparticles using Fe doping.

PubMed

Thurber, Aaron; Wingett, Denise G; Rasmussen, John W; Layne, Janet; Johnson, Lydia; Tenne, Dmitri A; Zhang, Jianhui; Hanna, Charles B; Punnoose, Alex

2012-06-01

This work reports a new method to improve our recent demonstration of zinc oxide (ZnO) nanoparticles (NPs) selectively killing certain human cancer cells, achieved by incorporating Fe ions into the NPs. Thoroughly characterized cationic ZnO NPs (∼6 nm) doped with Fe ions (Zn(1-x )Fe (x) O, x = 0-0.15) were used in this work, applied at a concentration of 24 μg/ml. Cytotoxicity studies using flow cytometry on Jurkat leukemic cancer cells show cell viability drops from about 43% for undoped ZnO NPs to 15% for ZnO NPs doped with 7.5% Fe. However, the trend reverses and cell viability increases with higher Fe concentrations. The non-immortalized human T cells are markedly more resistant to Fe-doped ZnO NPs than cancerous T cells, confirming that Fe-doped samples still maintain selective toxicity to cancer cells. Pure iron oxide samples displayed no appreciable toxicity. Reactive oxygen species generated with NP introduction to cells increased with increasing Fe up to 7.5% and decreased for >7.5% doping.

Erythrocyte CuZn superoxide dismutase activity is decreased in iron-deficiency anemia.

PubMed

Olivares, M; Araya, M; Pizarro, F; Letelier, A

2006-09-01

Iron and copper are essential microminerals that are intimately related. The present study was performed to determine the effect of iron-deficiency anemia (IDA) and treatment with iron on laboratory indicators of copper status. Hemoglobin, mean corpuscular volume erythrocyte Zn protoporphyrin, serum ferritin, serum copper, serum ceruloplasmin, and erythrocyte CuZn-superoxide dismutase (SOD) activity were studied in 12 adult women with IDA before and after iron treatment for 60-90 d (100 mg/d Fe, as ferric polymaltose) and in 27 women with normal iron status. Prior to treatment with iron, serum copper and ceruloplasmin were not different between the groups and treatment with iron did not affect these measures. IDA women, before and after treatment with iron, presented a 2.9- and 2-fold decrease in erythrocyte CuZn-SOD activity compared to women with normal iron status (p < 0.001). Treatment with iron increased erythrocyte CuZn-SOD activity of the IDA group; however, this change was not statistically significant. In conclusion, CuZn-SOD activity is decreased in IDA. Measurement of this enzyme activity is not useful for evaluating copper nutrition in iron-deficient subjects.

Soluble Supercapacitors: Large and Reversible Charge Storage in Colloidal Iron-Doped ZnO Nanocrystals.

PubMed

Brozek, Carl K; Zhou, Dongming; Liu, Hongbin; Li, Xiaosong; Kittilstved, Kevin R; Gamelin, Daniel R

2018-05-09

Colloidal ZnO semiconductor nanocrystals have previously been shown to accumulate multiple delocalized conduction-band electrons under chemical, electrochemical, or photochemical reducing conditions, leading to emergent semimetallic characteristics such as quantum plasmon resonances and raising prospects for application in multielectron redox transformations. Here, we demonstrate a dramatic enhancement in the capacitance of colloidal ZnO nanocrystals through aliovalent Fe 3+ -doping. Very high areal and volumetric capacitances (33 μF cm -2 , 233 F cm -3 ) are achieved in Zn 0.99 Fe 0.01 O nanocrystals that rival those of the best supercapacitors used in commercial energy-storage devices. The redox properties of these nanocrystals are probed by potentiometric titration and optical spectroscopy. These data indicate an equilibrium between electron localization by Fe 3+ dopants and electron delocalization within the ZnO conduction band, allowing facile reversible charge storage and removal. As "soluble supercapacitors", colloidal iron-doped ZnO nanocrystals constitute a promising class of solution-processable electronic materials with large charge-storage capacity attractive for future energy-storage applications.

Gain-of-function mutations identify amino acids within transmembrane domains of the yeast vacuolar transporter Zrc1 that determine metal specificity

PubMed Central

Lin, Huilan; Burton, Damali; Li, Liangtao; Warner, David E.; Phillips, John D.; Ward, Diane McVEY; Kaplan, Jerry

2015-01-01

Cation diffusion facilitator transporters are found in all three Kingdoms of life and are involved in transporting transition metals out of the cytosol. The metals they transport include Zn2+, Co2+, Fe2+, Cd2+, Ni2+ and Mn2+; however, no single transporter transports all metals. Previously we showed that a single amino acid mutation in the yeast vacuolar zinc transporter Zrc1 changed its substrate specificity from Zn2+ to Fe2+ and Mn2+ [Lin, Kumanovics, Nelson, Warner, Ward and Kaplan (2008) J. Biol. Chem. 283, 33865–33873]. Mutant Zrc1 that gained iron transport activity could protect cells with a deletion in the vacuolar iron transporter (CCC1) from high iron toxicity. Utilizing suppression of high iron toxicity and PCR mutagenesis of ZRC1, we identified other amino acid substitutions within ZRC1 that changed its metal specificity. All Zrc1 mutants that transported Fe2+ could also transport Mn2+. Some Zrc1 mutants lost the ability to transport Zn2+, but others retained the ability to transport Zn2+. All of the amino acid substitutions that resulted in a gain in Fe2+ transport activity were found in transmembrane domains. In addition to alteration of residues adjacent to the putative metal-binding site in two transmembrane domains, alteration of residues distant from the binding site affected substrate specificity. These results suggest that substrate selection involves co-operativity between transmembrane domains. PMID:19538181

Bimetallic Porous Iron (pFe) Materials for Remediation/Removal of Tc from Aqueous Systems

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

Li, D.

Remediation of Tc remains an unresolved challenge at SRS and other DOE sites. The objective of this project was to develop novel bimetallic porous iron (pFe) materials for Tc removal from aqueous systems. We showed that the pFe is much more effective in removing TcO 4 - (×30) and ReO 4 - (×8) from artificial groundwater than granular iron. Tc K-edge XANES spectroscopy indicated that Tc speciation on the pFe was 18% adsorbed TcO 4 -, 28% Tc(IV) in Tc dioxide and 54% Tc(IV) into the structure of Fe hydroxide. A variety of catalytic metal nanoparticles (i.e., Ni, Cu, Zn,more » Ag, Sn and Pd) were successfully deposited on the pFe using scalable chemical reduction methods. The Zn-pFe was outstanding among the six bimetallic pFe materials, with a capacity increase of >100% for TcO 4 - removal and of 50% for ReO 4 - removal, compared to the pFe. These results provide a highly applicable platform for solving critical DOE and industrial needs related to nuclear environmental stewardship and nuclear power production.« less

Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification

PubMed Central

Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

2015-01-01

Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2′-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation. PMID:26287170

Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia

PubMed Central

Shuhaimi-Othman, M.; Nadzifah, Y.; Nur-Amalina, R.; Umirah, N. S.

2012-01-01

Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L−1, respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L−1 and 9.0, 2.0, 19.9, and 36.7 μg L−1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358

Route and Regulation of Zinc, Cadmium, and Iron Transport in Rice Plants (Oryza sativa L.) during Vegetative Growth and Grain Filling: Metal Transporters, Metal Speciation, Grain Cd Reduction and Zn and Fe Biofortification.

PubMed

Yoneyama, Tadakatsu; Ishikawa, Satoru; Fujimaki, Shu

2015-08-13

Zinc (Zn) and iron (Fe) are essential but are sometimes deficient in humans, while cadmium (Cd) is toxic if it accumulates in the liver and kidneys at high levels. All three are contained in the grains of rice, a staple cereal. Zn and Fe concentrations in rice grains harvested under different levels of soil/hydroponic metals are known to change only within a small range, while Cd concentrations show greater changes. To clarify the mechanisms underlying such different metal contents, we synthesized information on the routes of metal transport and accumulation in rice plants by examining metal speciation, metal transporters, and the xylem-to-phloem transport system. At grain-filling, Zn and Cd ascending in xylem sap are transferred to the phloem by the xylem-to-phloem transport system operating at stem nodes. Grain Fe is largely derived from the leaves by remobilization. Zn and Fe concentrations in phloem-sap and grains are regulated within a small range, while Cd concentrations vary depending on xylem supply. Transgenic techniques to increase concentrations of the metal chelators (nicotianamine, 2'-deoxymugineic acid) are useful in increasing grain Zn and Fe concentrations. The elimination of OsNRAMP5 Cd-uptake transporter and the enhancement of root cell vacuolar Cd sequestration reduce uptake and root-to-shoot transport, respectively, resulting in a reduction of grain Cd accumulation.

Changes in iron, zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility.

PubMed

Greffeuille, Valérie; Polycarpe Kayodé, A P; Icard-Vernière, Christèle; Gnimadi, Muriel; Rochette, Isabelle; Mouquet-Rivier, Claire

2011-06-15

The effect of the different unit operations of processing traditionally used to produce four maize foods commonly consumed in Africa on the nutritional composition of the products was investigated, using Benin as a study context. The impact of the processes on lipid, fibre, phytate, iron and zinc contents varied with the process. The lowest IP6/Fe and IP6/Zn molar ratios, the indices used to assess Fe and Zn bioavailability were obtained in mawè, a fermented dough. Analysis of maize products highlighted a significant increase in iron content after milling, as a result of contamination by the equipment used. Evaluation of iron bioaccessibility by in vitro enzymatic digestion followed by dialysis revealed that the iron contamination, followed by lactic acid fermentation, led to a considerable increase in bioaccessible iron content. Extrinsic iron supplied to food products by the milling equipment could play a role in iron intake in developing countries. Copyright © 2010 Elsevier Ltd. All rights reserved.

Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

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

Frierdich, Andrew J.; Catalano, Jeffrey G.

2012-03-26

Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occursmore » near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.« less

Biofortification with Iron and Zinc Improves Nutritional and Nutraceutical Properties of Common Wheat Flour and Bread.

PubMed

Ciccolini, Valentina; Pellegrino, Elisa; Coccina, Antonio; Fiaschi, Anna Ida; Cerretani, Daniela; Sgherri, Cristina; Quartacci, Mike Frank; Ercoli, Laura

2017-07-12

The effect of field foliar Fe and Zn biofortification on concentration and potential bioavailability of Fe and Zn and health-promoting compounds was studied in wholemeal flour of two common wheat varieties (old vs modern). Moreover, the effect of milling and bread making was studied. Biofortification increased the concentration of Zn (+78%) and its bioavailability (+48%) in the flour of the old variety, whereas it was ineffective in increasing Fe concentration in both varieties. However, the old variety showed higher concentration (+41%) and bioavailability (+26%) of Fe than the modern one. As regard milling, wholemeal flour had higher Fe, Zn concentration and health-promoting compounds compared to white flour. Bread making slightly change Fe and Zn concentration but greatly increased their bioavailability (77 and 70%, respectively). All these results are of great support for developing a production chain of enriched functional bread having a protective role against chronic cardio-vascular diseases.

Evaluation of Serum Levels of Zinc, Copper, Iron, and Zinc/Copper Ratio in Cutaneous Leishmaniasis

PubMed Central

Pourfallah, F; Javadian, S; Zamani, Z; Saghiri, R; Sadeghi, S; Zarea, B; Faiaz, Sh; Mirkhani, F; Fatemi, N

2009-01-01

Background: The purpose of this study was to evaluate the levels of zinc (Zn), copper (Cu), iron (Fe) and zinc/ copper ratio in the serum of patients with cutaneous leishmaniasis in Qom Province, center of Iran. Methods: Serum levels of zinc and copper were determined by flame atomic absorption spectrophotometer and serum iron concentration was measured by using an Auto Analyzer. The study group consisted of 60 patients with cutaneous leishmaniasis and the control group of 100 healthy volunteers from the same area who were not exposed to cutaneous leishmaniasis. Result: There were no statistically significant differences in age and body mass index between the two groups. Serum Zn (P< 0.001) and Fe (P< 0.05) levels were lower in patients with cutaneous leishmaniasis than the control group. We also found serum Cu concentration (P< 0.05) in the patient group was significantly higher than that of the control group. However, zinc/ copper ratio (P< 0.001) was lower in patients with cutaneous leishmaniasis than in the control group. Conclusion: Our data indicated that Zn/Cu ratio was significantly lower in patients with CL as compared to the controls. Earlier reports suggest that, this ratio imbalance could be a useful marker for immune dysfunction in leishmaniasis. There was also strong association of Zn, Cu and Fe with CL. It suggests the use of blood zinc, copper, iron concentration and the copper/zinc ratio (Zn/Cu), as a means for estimating the prognosis of CL. PMID:22808376

Effect of assistant rf field on phase composition of iron nitride film prepared by magnetron sputtering process

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

Li, W.L.; Zheng, F.; Fei, W.D.

2006-01-15

Fe-N thin films were fabricated using a direct current magnetron sputtering process assisted by a radio-frequency (rf) field. The effect of the rf field on the phase composition of the films was investigated. The results indicate that with the assistance of the rf field, various kinds of iron nitrides can be obtained in the films, including {alpha}{sup '}-Fe-N, {alpha}{sup ''}-Fe{sub 16}N{sub 2}, {xi}-Fe{sub 2}N, {epsilon}-Fe{sub 3}N, and {gamma}{sup ''}-FeN with ZnS structure. It was found that the rf field greatly benefits the formation of iron nitrides in the Fe-N films.

The role of iron(II) dilution in the magnetic and photomagnetic properties of the series [Fe(x)Zn(1-x)(bpp)₂](NCSe)₂.

PubMed

Baldé, Chérif; Desplanches, Cédric; Le Gac, Fréderic; Guionneau, Philippe; Létard, Jean-François

2014-06-07

The effects of metal dilution on the spin-crossover behavior of iron(II) in the mixed crystal series [Fe(x)Zn(1-x)(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) have been studied using magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. For each mixed-crystal system, the thermal spin transition temperature, T(1/2), and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T(1/2) decreases with the metal dilution while T(LIESST) remains unchanged. Dilution also tends to decrease the hysteresis width and smooth the transition curves. These effects were discussed first qualitatively and then quantitatively on the basis of a kinetic study governing the photo-induced back conversion taking into account the relative sizes of Zn(II) and Fe(II) ions. Interestingly, single crystals were obtained for [Fe(0.6)Zn(0.4)(bpp)2](NCSe)2 allowing the X-ray diffraction crystal-structure determination.

Enriching rice with Zn and Fe while minimizing Cd risk

PubMed Central

Slamet-Loedin, Inez H.; Johnson-Beebout, Sarah E.; Impa, Somayanda; Tsakirpaloglou, Nikolaos

2015-01-01

Enriching iron (Fe) and zinc (Zn) content in rice grains, while minimizing cadmium (Cd) levels, is important for human health and nutrition. Natural genetic variation in rice grain Zn enables Zn-biofortification through conventional breeding, but limited natural Fe variation has led to a need for genetic modification approaches, including over-expressing genes responsible for Fe storage, chelators, and transporters. Generally, Cd uptake and allocation is associated with divalent metal cations (including Fe and Zn) transporters, but the details of this process are still unknown in rice. In addition to genetic variation, metal uptake is sometimes limited by its bioavailability in the soil. The availability of Fe, Zn, and Cd for plant uptake varies widely depending on soil redox potential. The typical practice of flooding rice increases Fe while decreasing Zn and Cd availability. On the other hand, moderate soil drying improves Zn uptake but also increases Cd and decreases Fe uptake. Use of Zn- or Fe-containing fertilizers complements breeding efforts by providing sufficient metals for plant uptake. In addition, the timing of nitrogen fertilization has also been shown to affect metal accumulation in grains. The purpose of this mini-review is to identify knowledge gaps and prioritize strategies for improving the nutritional value and safety of rice. PMID:25814994

Effect of Transport and Aging Processes on Metal Speciation in Iron Oxyhydroxide Aggregates, Tar Creek Superfund Site, Oklahoma

NASA Astrophysics Data System (ADS)

Estes, E. R.; Schaider, L. A.; Shine, J. P.; Brabander, D. J.

2010-12-01

Following the cessation of mining activity in the late 20th century, Tar Creek Superfund Site was left highly contaminated by Pb, Zn, and Cd. Tar Creek, which flows through the site and into the Neosho River, has been studied extensively because of its potential to transport metals from the mining site to downstream communities. Previous research identified aggregated iron oxyhydroxide material, which forms when mine seepage mixes with Tar Creek surface water, as a major transport vector of metals. Frequent flooding in Tar Creek deposits aggregates on downstream floodplains, where wetting and drying processes alter the speciation of iron and other metals. This study seeks to better quantify those changes and to determine how transport and aging affects the human and ecological health risk. Sequential extractions of aggregate samples collected from the creek demonstrate that Fe is present in both amorphous (10-35% of Fe extracted) and more crystalline (8-23% of Fe extracted) phases. Substantial portions of heavy metals sorb to amorphous iron oxyhydroxide phases (accounting for 10-30% of Pb and Zn extracted) but are not associated with more crystalline iron oxide phases (representing only 1% or less of the Pb and Zn extracted). Samples have a high organic matter content (18-25% mass loss on ignition), but only Fe was significantly extracted by the oxidizing step targeting organic matter (1-2% of Pb and Zn extracted, but 10-26% of Fe extracted). The majority of metals were extracted by the soluble or residual steps. If metals and organic matter inhibit transformation of amorphous iron oxyhydroxide material to nano and crystalline iron oxides, then a steady-state volume of amorphous iron oxyhydroxide material with a high total sorption capacity may exist within Tar Creek, enhancing the metal flux accommodated by this transport mechanism. Once transported downstream and deposited on floodplains, however, it is hypothesized that repeated changes in soil matrix composition and thermodynamic conditions could facilitate a transformation to more crystalline iron phases and increase metal bioavailability. While preliminary data from in-creek aggregates show no clear trend in mineralogical composition with downstream transport, only the furthest downstream samples have 2-line ferrihydrite in amounts detectable by XRD.

Application of iron and zinc isotopes to track the sources and mechanisms of metal loading in a mountain watershed

USGS Publications Warehouse

Borrok, D.M.; Wanty, R.B.; Ian, Ridley W.; Lamothe, P.J.; Kimball, B.A.; Verplanck, P.L.; Runkel, R.L.

2009-01-01

Here the hydrogeochemical constraints of a tracer dilution study are combined with Fe and Zn isotopic measurements to pinpoint metal loading sources and attenuation mechanisms in an alpine watershed impacted by acid mine drainage. In the tested mountain catchment, ??56Fe and ??66Zn isotopic signatures of filtered stream water samples varied by ???3.5??? and 0.4???, respectively. The inherent differences in the aqueous geochemistry of Fe and Zn provided complimentary isotopic information. For example, variations in ??56Fe were linked to redox and precipitation reactions occurring in the stream, while changes in ??66Zn were indicative of conservative mixing of different Zn sources. Fen environments contributed distinctively light dissolved Fe (<-2.0???) and isotopically heavy suspended Fe precipitates to the watershed, while Zn from the fen was isotopically heavy (>+0.4???). Acidic drainage from mine wastes contributed heavier dissolved Fe (???+0.5???) and lighter Zn (???+0.2???) isotopes relative to the fen. Upwelling of Fe-rich groundwater near the mouth of the catchment was the major source of Fe (??56Fe ??? 0???) leaving the watershed in surface flow, while runoff from mining wastes was the major source of Zn. The results suggest that given a strong framework for interpretation, Fe and Zn isotopes are useful tools for identifying and tracking metal sources and attenuation mechanisms in mountain watersheds. ?? 2009 Elsevier Ltd.

Mapping Quantitative Trait Loci Controlling High Iron and Zinc Content in Self and Open Pollinated Grains of Pearl Millet [Pennisetum glaucum (L.) R. Br.

PubMed Central

Kumar, Sushil; Hash, Charles T.; Thirunavukkarasu, Nepolean; Singh, Govind; Rajaram, Vengaldas; Rathore, Abhishek; Senapathy, Senthilvel; Mahendrakar, Mahesh D.; Yadav, Rattan S.; Srivastava, Rakesh K.

2016-01-01

Pearl millet is a multipurpose grain/fodder crop of the semi-arid tropics, feeding many of the world’s poorest and most undernourished people. Genetic variation among adapted pearl millet inbreds and hybrids suggests it will be possible to improve grain micronutrient concentrations by selective breeding. Using 305 loci, a linkage map was constructed to map QTLs for grain iron [Fe] and zinc [Zn] using replicated samples of 106 pearl millet RILs (F6) derived from ICMB 841-P3 × 863B-P2. The grains of the RIL population were evaluated for Fe and Zn content using atomic absorption spectrophotometer. Grain mineral concentrations ranged from 28.4 to 124.0 ppm for Fe and 28.7 to 119.8 ppm for Zn. Similarly, grain Fe and Zn in open pollinated seeds ranged between 22.4–77.4 and 21.9–73.7 ppm, respectively. Mapping with 305 (96 SSRs; 208 DArT) markers detected seven linkage groups covering 1749 cM (Haldane) with an average intermarker distance of 5.73 cM. On the basis of two environment phenotypic data, two co-localized QTLs for Fe and Zn content on linkage group (LG) 3 were identified by composite interval mapping (CIM). Fe QTL explained 19% phenotypic variation, whereas the Zn QTL explained 36% phenotypic variation. Likewise for open pollinated seeds, the QTL analysis led to the identification of two QTLs for grain Fe content on LG3 and 5, and two QTLs for grain Zn content on LG3 and 7. The total phenotypic variance for Fe and Zn QTLs in open pollinated seeds was 16 and 42%, respectively. Analysis of QTL × QTL and QTL × QTL × environment interactions indicated no major epistasis. PMID:27933068

[Interaction among the trace elements zinc, copper and iron after depletion and repletion of dairy cows with zinc].

PubMed

Kirchgessner, M; Schwarz, F J; Roth, H P; Schwarz, W A

1978-12-01

Imbalances in the supply with trace elements may be caused by the excessive administration of one or several elements or the insufficient administration in relation to other trace elements. This article deals with the interactions between the trace elements zinc and copper resp. zinc and iron under the conditions of the insufficient supply with Zn (6 mg per kg dry matter of the fodder) and the supply according to the demand with other trace elements (14 mg copper resp. 83 mg iron per dry matter of the fodder). For this purpose we investigated the copper, iron and zinc content of the milk and the serum of cows that were first depleted of zinc through a semi-synthetic zinc deficiency diet and then repleted with extra allowances of zinc. The closest connections exist between the copper and zinc content of the milk. Thus extreme Zn-deficiency feeding conditions the decreased Zn-content on the one hand and increased Cu-content on the other. In contrast to this, the cows' Zn-excretion in the milk increases after Zn-repletion whereas the Cu-content decreases. This shows a distinctly negative correlation. A loose connection could only be detected for the Cu- and Zn-content of the serum. Though the Zn-content changed considerably in dependence on the Zn-supply, the Cu-content remained largely uninfluenced. The Fe-content of both milk and serum shows no interaction with the nutritive Zn-supply. Only after 19 test weeks of extreme Zn-deficiency could a slight increase of the Fe-concentration be indicated.

Iron limitation of microbial phosphorus acquisition in the tropical North Atlantic

NASA Astrophysics Data System (ADS)

Browning, Thomas; Achterberg, Eric; Yong, Jaw Chuen; Rapp, Insa; Utermann, Caroline; Engel, Anja; Moore, Mark

2017-04-01

Growth-limitation of marine phytoplankton by fixed nitrogen (N) has been demonstrated for most of the low-latitude oceans; however, in the (sub)tropical North Atlantic enhanced N2 fixation leads to secondary/(co-)limitation by phosphorus (P). The dissolved organic P pool is rarely fully depleted in the modern ocean and potentially represents a substantial additional P source. Microbes can use a variety of alkaline phosphatase enzymes to access P from a major fraction of this pool. In contrast to the relatively well studied PhoA family of alkaline phosphatases that utilize zinc (Zn) as a cofactor, the recent discovery of iron (Fe) as a cofactor in the more widespread PhoX[1] and PhoD[2] enzymes imply potential for a complex, biochemically-dependant interplay between oceanic Zn, Fe and P cycles. Here we demonstrate enhanced natural community alkaline phosphatase activity (APA) following Fe amendment within the low Zn and moderately low Fe western tropical North Atlantic. In contrast, beneath the Saharan dust plume in the Eastern Atlantic no APA response to trace metal addition was observed. This is the first demonstration of intermittent Fe limitation of microbial P acquisition, providing an additional facet in the argument for Fe control of the coupling between oceanic N and P cycles. 1. Yong, S. C. et al. A complex iron-calcium cofactor catalyzing phosphotransfer chemistry. Science 345, 1170-3 (2014). 2. Rodriguez, F. et al. Crystal structure of the Bacillus subtilis phosphodiesterase PhoD reveals an iron and calcium-containing active site. J. Biol. Chem. 289, 30889-30899 (2014).

Use of ferrous iron by metallo-β-lactamases.

PubMed

Cahill, Samuel T; Tarhonskaya, Hanna; Rydzik, Anna M; Flashman, Emily; McDonough, Michael A; Schofield, Christopher J; Brem, Jürgen

2016-10-01

Metallo-β-lactamases (MBLs) catalyse the hydrolysis of almost all β-lactam antibacterials including the latest generation carbapenems and are a growing worldwide clinical problem. It is proposed that MBLs employ one or two zinc ion cofactors in vivo. Isolated MBLs are reported to use transition metal ions other than zinc, including copper, cadmium and manganese, with iron ions being a notable exception. We report kinetic and biophysical studies with the di-iron(II)-substituted metallo-β-lactamase II from Bacillus cereus (di-Fe(II) BcII) and the clinically relevant B1 subclass Verona integron-encoded metallo-β-lactamase 2 (di-Fe(II) VIM-2). The results reveal that MBLs can employ ferrous iron in catalysis, but with altered kinetic and inhibition profiles compared to the zinc enzymes. A crystal structure of di-Fe(II) BcII reveals only small overall changes in the active site compared to the di-Zn(II) enzyme including retention of the di-metal bridging water; however, the positions of the metal ions are altered in the di-Fe(II) compared to the di-Zn(II) structure. Stopped-flow analyses reveal that the mechanism of nitrocefin hydrolysis by both di-Fe(II) BcII and di-Fe(II) VIM-2 is altered compared to the di-Zn(II) enzymes. Notably, given that the MBLs are the subject of current medicinal chemistry efforts, the results raise the possibility the Fe(II)-substituted MBLs may be of clinical relevance under conditions of low zinc availability, and reveal potential variation in inhibitor activity against the differently metallated MBLs. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds

NASA Astrophysics Data System (ADS)

Licht, Stuart; Naschitz, Vera; Liu, Bing; Ghosh, Susanta; Halperin, Nadezhda; Halperin, Leonid; Rozen, Dmitri

The chemical preparation of high purity potassium and barium ferrates for alkaline electrochemical storage are presented. The synthesized salts are used to demonstrate a variety of high capacity super-iron (Zn anode) alkaline AAA cell configurations which utilize these Fe(V) salts. Results of 500 days, full stability, of the synthesized K 2FeO 4 are presented. Synthetic pathways yielding 80-100 g of 96.5-99.5% pure K 2FeO 4 and BaFeO 4 are presented, and the products of these syntheses are demonstrated to provide a high energy electrochemical discharge in a variety of AAA alkaline cells. BaFeO 4 super-iron alkaline AAA cells provide over 0.8 W h during 2.8 Ω discharge, yielding over 200% higher capacity than conventional alkaline batteries. The barium super-iron cell configurations studied provide higher capacity than the potassium super-iron alkaline cell configurations studied.

Preparation of magnetic and bioactive calcium zinc iron silicon oxide composite for hyperthermia treatment of bone cancer and repair of bone defects.

PubMed

Jiang, Yumin; Ou, Jun; Zhang, Zhanhe; Qin, Qing-Hua

2011-03-01

In this paper, a calcium zinc iron silicon oxide composite (CZIS) was prepared using the sol-gel method. X-ray diffraction (XRD) was then employed to test the CZIS composite. The results from the test showed that the CZIS had three prominent crystalline phases: Ca(2)Fe(1.7)Zn(0.15)Si(0.15)O(5), Ca(2)SiO(4), and ZnFe(2)O(4). Calorimetric measurements were then performed using a magnetic induction furnace. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis were conducted to confirm the growth of a precipitated hydroxyapatite phase after immersion in simulated body fluid (SBF). Cell culture experiments were also carried out, showing that the CZIS composite more visibly promoted osteoblast proliferation than ZnFe(2)O(4) glass ceramic and HA, and osteoblasts adhered and spread well on the surfaces of composite samples.

Seed priming with iron and zinc in bread wheat: effects in germination, mitosis and grain yield.

PubMed

Reis, Sara; Pavia, Ivo; Carvalho, Ana; Moutinho-Pereira, José; Correia, Carlos; Lima-Brito, José

2018-07-01

Currently, the biofortification of crops like wheat with micronutrients such as iron (Fe) and zinc (Zn) is extremely important due to the deficiencies of these micronutrients in the human diet and in soils. Agronomic biofortification with Fe and Zn can be done through different exogenous strategies such as soil application, foliar spraying, and seed priming. However, the excess of these micronutrients can be detrimental to the plants. Therefore, in the last decade, a high number of studies focused on the evaluation of their phytotoxic effects to define the best strategies for biofortification of bread wheat. In this study, we investigated the effects of seed priming with different dosages (1 mg L -1 to 8 mg L -1 ) of Fe and/or Zn in germination, mitosis and yield of bread wheat cv. 'Jordão' when compared with control. Overall, our results showed that: micronutrient dosages higher than 4 mg L -1 negatively affect the germination; Fe and/or Zn concentrations higher than 2 mg L -1 significantly decrease the mitotic index and increase the percentage of dividing cells with anomalies; treatments performed with 8 mg L -1 of Fe and/or 8 mg L -1 Zn caused negative effects in germination, mitosis and grain yield. Moreover, seed priming with 2 mg L -1 Fe + 2 mg L -1 Zn has been shown to be non-cytotoxic, ensuring a high rate of germination (80%) and normal dividing cells (90%) as well as improving tillering and grain yield. This work revealed that seed priming with Fe and Zn micronutrients constitutes a useful and alternative approach for the agronomic biofortification of bread wheat.

New tris(dopamine) derivative as an iron chelator. Synthesis, solution thermodynamic stability, and antioxidant research.

PubMed

Zhang, Qingchun; Jin, Bo; Shi, Zhaotao; Wang, Xiaofang; Lei, Shan; Tang, Xingyan; Liang, Hua; Liu, Qiangqiang; Gong, Mei; Peng, Rufang

2017-06-01

A new tris(dopamine) derivative, containing three dopamine chelate moieties which were attached to a trimesic acid molecular scaffold, has been prepared and fully characterized by NMR, FTIR and HRMS. The solution thermodynamic stability of the chelator with Fe(III), Mg(II), Zn(II) and Fe(II) ions was investigated. Results demonstrated that the chelator exhibited effective binding ability and improved selectivity to Fe(III) ion. The chelator possessed affinity similar to that of diethylenetriaminepentaacetic acid chelator for Fe(III) ion. The high affinity could be attributed to the favorable geometric arrangement between the chelator and Fe(III) ion coordination preference. The chelator also exhibited high antioxidant activity and nontoxicity to neuron-like rat pheochromocytoma cells. Hence, the chelator could be used as chelating agent for iron overload situations without depleting essential metal ions, such as Mg(II) and Zn(II) ions. Copyright © 2017. Published by Elsevier Inc.

Electromagnetic interference attenuation and shielding effect of quaternary Epoxy-PPy/Fe3O4-ZnO nanocomposite as a broad band microwave-absorber

NASA Astrophysics Data System (ADS)

Olad, Ali; Shakoori, Sahar

2018-07-01

An increase in the electromagnetic wave pollution generated from wireless telecommunication devices has devoted to a great request for exploiting microwave absorbing materials for themselves. The combination of inherently conducting polymers such as polypyrrole (PPy) with metal oxides has led to design ideal microwave absorbing materials which benefit both advantage effects of ICPs and metal oxide nanoparticles. Herein, the quaternary nanocomposite of Epoxy-PPy/Fe3O4-ZnO was prepared and tested for the absorption of X-band microwaves. Simultaneous application of metal oxides and conducting polypyrrole in the epoxy matrix was evaluated in order to increase the absorption intensity and broadness of microwaves in X-band region. The morphology, microstructure, and phase structure of Fe3O4, ZnO, and PPy, as well as quaternary nanocomposite were characterized and studied using FTIR, XRD, FESEM and TEM techniques. The presence of nanoparticles in the quaternary nanocomposite was confirmed by EDS. The magnetization of iron oxide was studied by VSM. The synergetic effect of iron oxide and zinc oxide nanoparticles in different weight ratios (Fe3O4/ZnO) on the electromagnetic wave absorption was evaluated. The electromagnetic parameters have been evaluated by the vector network analyzer in the frequency range of 8.2-12.4 GHz which is named as X-band region and is adequate for radar applications. The electromagnetic wave absorbing outcomes indicated that Epoxy-PPy/Fe3O4-ZnO quaternary nanocomposite has wide absorption area and high attenuation, which is believed to be due to dielectric loss properties related to the polypyrrole, magnetic loss factor of Fe3O4, and synergetic effects of components. The maximum reflection loss reached to -32.53 dB at 9.96 GHz with a nanocomposite thickness of 2 mm which is dedicated to the Epoxy-PPy/Fe3O4-ZnO with iron oxide to zinc oxide ratio of 2:1. The absorption bandwidth with the reflection loss lower than -10 dB (90% attenuation) was up to 4.2 GHz that covering a frequency range of 8.2-12.4 GHz. Results showed that absorber having %15 (w/w) polypyrrole/epoxy resin in Epoxy-PPy/Fe3O4-ZnO nanocomposite with iron oxide to zinc oxide ratio of 2:1 displays the best reflection loss properties. The loss curves illustrated the values of dielectric loss tangent and magnetic loss tangent of prepared nanocomposites which are in the range of 0.25-0.7 and -0.08 to 0.09 respectively. Therefore, microwave absorption mechanism is probably attributed to dielectric loss.

Hierarchical magnetic petal-like Fe3O4-ZnO@g-C3N4 for removal of sulfamethoxazole, suppression of photocorrosion, by-products identification and toxicity assessment.

PubMed

Mirzaei, Amir; Chen, Zhi; Haghighat, Fariborz; Yerushalmi, Laleh

2018-08-01

Herein, a petal-like photocatalyst, Fe 3 O 4 -ZnO@g-C 3 N 4 (FZG) with different g-C 3 N 4 to ZnO ratios was synthesized with hierarchical structure. The FZG1 photocatalyst, having the weight ratio of 1:1 for the initial urea and Fe 3 O 4 -ZnO (Fe-ZnO), presented the highest sulfamethoxazole (SMX) degradation rate of 0.0351 (min -1 ), which was 2.6 times higher than that of pristine ZnO. Besides the facile separation, the performance of photocatalyst was improved due to the function of iron oxide as an electron acceptor that reduced the electron/hole recombination rate. The coating of g-C 3 N 4 on the Fe-ZnO surface not only acted as a protective layer for ZnO against photocorrosion, but it also enhanced the photocatalytic activity of the catalyst for SMX degradation through the heterojunction mechanism. By using the FZG1 photocatalyst, 95% SMX removal was obtained after 90 min reaction, while 47% COD and 30% TOC removal were achieved after 60 min treatment under a low energy-consuming UV lamp (10 W). Moreover, a substantial reduction in the solution toxicity was shown after the treatment, as compared with the SMX solution before treatment. The LC-HR-MS/MS analysis results showed that the concentration of most detected by-products produced after 90 min reaction by FZG1 was considerably lower than those obtained using other synthesized photocatalysts. By performing radical scavenging experiments, OH ° radical was found to be the major reactive species. The FZG1 photocatalyst also displayed excellent reusability in five cycles and the leaching of zinc and iron ions was reduced by 54% and ∼100%, respectively, after coating Fe-ZnO with g-C 3 N 4 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterisation of zinc in slags originated from a contaminated sediment by coupling /μ-PIXE, /μ-RBS, /μ-EXAFS and powder EXAFS spectroscopy

NASA Astrophysics Data System (ADS)

Isaure, M. P.; Laboudigue, A.; Manceau, A.; Sarret, G.; Tiffreau, C.; Trocellier, P.

2001-07-01

Depositing dredged sediments on soils is usual but it is a hazardous practice for the local environment when these sediments are polluted by heavy metals. This chemical hazard can be assessed by determining the speciation of metals. In this study, slags highly polluted with Zn and originated from a contaminated dredged sediment were investigated. Zn speciation was studied by laterally resolved techniques such as μ-particle induced X-ray emission (μ-PIXE), μ-Rutherford backscattering spectrometry (μ-RBS), μ-extended X-ray absorption fine structure (μ-EXAFS), and bulk analyses such as powder EXAFS spectroscopy. μ-PIXE and μ-RBS results showed that high concentrations of Zn were associated with S in localised areas at the surface of the slags while moderate amounts of Zn were mainly associated with Fe in the matrix. EXAFS results allowed to identify ZnS and Zn sorbed on ferrihydrite (5Fe 2O 3·9H 2O), proxy for iron oxy-hydroxides, as the main Zn-bearing phases. The occurrence of this Zn-iron oxy-hydroxide is interpreted as a mobilisation of Zn released from ZnS oxidation.

Biofortified indica rice attains iron and zinc nutrition dietary targets in the field

PubMed Central

Trijatmiko, Kurniawan R.; Dueñas, Conrado; Tsakirpaloglou, Nikolaos; Torrizo, Lina; Arines, Felichi Mae; Adeva, Cheryl; Balindong, Jeanette; Oliva, Norman; Sapasap, Maria V.; Borrero, Jaime; Rey, Jessica; Francisco, Perigio; Nelson, Andy; Nakanishi, Hiromi; Lombi, Enzo; Tako, Elad; Glahn, Raymond P.; Stangoulis, James; Chadha-Mohanty, Prabhjit; Johnson, Alexander A. T.; Tohme, Joe; Barry, Gerard; Slamet-Loedin, Inez H.

2016-01-01

More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g−1 iron (Fe) and 16 μg g−1 zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g−1 Fe and 28 μg g−1 Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g−1 in glasshouse settings; in contrast, under field conditions, 4 μg g−1 was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g−1 Fe and 45.7 μg g−1 Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase (OsNAS2) and soybean ferritin (SferH-1) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds. PMID:26806528

Insights into the effect of iron and cobalt doping on the structure of nanosized ZnO.

PubMed

Giuli, Gabriele; Trapananti, Angela; Mueller, Franziska; Bresser, Dominic; d'Acapito, Francesco; Passerini, Stefano

2015-10-05

Here we report an in-depth structural characterization of transition metal-doped zinc oxide nanoparticles that have recently been used as anode materials for Li-ion batteries. Structural refinement of powder X-ray diffraction (XRD) data allowed the determination of small though reproducible changes in the unit cell dimensions of four ZnO samples (wurtzite structure) prepared with different dopants or different synthesis conditions. Moreover, large variations of the full width at half-maximum of the XRD reflections indicate that the crystallinity of the samples decreases in the order ZnO, Zn0.9Co0.1O, Zn0.9Fe0.1O/C, and Zn0.9Fe0.1O (the crystallite sizes as determined by Williamson-Hall plots are 42, 29, 15, and 13 nm, respectively). X-ray absorption spectroscopy data indicate that Co is divalent, whereas Fe is purely trivalent in Zn0.9Fe0.1O and 95% trivalent (Fe(3+)/(Fe(3+) + Fe(2+)) ratio = 0.95) in Zn0.9Fe0.1O/C. The aliovalent substitution of Fe(3+) for Zn(2+) implies the formation of local defects around Fe(3+) such as cationic vacancies or interstitial oxygen for charge balance. The EXAFS (extended X-ray absorption fine structure) data, besides providing local Fe-O and Co-O bond distances, are consistent with a large amount of charge-compensating defects. The Co-doped sample displays similar EXAFS features to those of pure ZnO, suggesting the absence of a large concentration of defects as found in the Fe-doped samples. These results are of substantial importance for understanding and elucidating the modified electrochemical lithiation mechanism by introducing transition metal dopants into the ZnO structure for the application as lithium-ion anode material.

Tuning the Redox Properties of a Nonheme Iron(III)-Peroxo Complex Binding Redox-Inactive Zinc Ions by Water Molecules.

PubMed

Lee, Yong-Min; Bang, Suhee; Yoon, Heejung; Bae, Seong Hee; Hong, Seungwoo; Cho, Kyung-Bin; Sarangi, Ritimukta; Fukuzumi, Shunichi; Nam, Wonwoo

2015-07-20

Redox-inactive metal ions play important roles in tuning chemical properties of metal-oxygen intermediates. Herein we report the effect of water molecules on the redox properties of a nonheme iron(III)-peroxo complex binding redox-inactive metal ions. The coordination of two water molecules to a Zn(2+) ion in (TMC)Fe(III) -(O2 )-Zn(CF3 SO3 )2 (1-Zn(2+) ) decreases the Lewis acidity of the Zn(2+) ion, resulting in the decrease of the one-electron oxidation and reduction potentials of 1-Zn(2+) . This further changes the reactivities of 1-Zn(2+) in oxidation and reduction reactions; no reaction occurred upon addition of an oxidant (e.g., cerium(IV) ammonium nitrate (CAN)) to 1-Zn(2+) , whereas 1-Zn(2+) coordinating two water molecules, (TMC)Fe(III) -(O2 )-Zn(CF3 SO3 )2 -(OH2 )2 [1-Zn(2+) -(OH2 )2 ], releases the O2 unit in the oxidation reaction. In the reduction reactions, 1-Zn(2+) was converted to its corresponding iron(IV)-oxo species upon addition of a reductant (e.g., a ferrocene derivative), whereas such a reaction occurred at a much slower rate in the case of 1-Zn(2+) -(OH2 )2 . The present results provide the first biomimetic example showing that water molecules at the active sites of metalloenzymes may participate in tuning the redox properties of metal-oxygen intermediates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tuning the Redox Properties of a Nonheme Iron(III)-Peroxo Complex Binding Redox-Inactive Zinc Ions by Water Molecules

DOE PAGES

Lee, Yong-Min; Bang, Suhee; Yoon, Heejung; ...

2015-06-19

Here we report redox-inactive metal ions play important roles in tuning chemical properties of metal–oxygen intermediates. We describe the effect of water molecules on the redox properties of a nonheme iron(III)–peroxo complex binding redox-inactive metal ions. The coordination of two water molecules to a Zn 2+ ion in (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2 (1-Zn 2+) decreases the Lewis acidity of the Zn 2+ ion, resulting in the decrease of the one-electron oxidation and reduction potentials of 1-Zn 2+. This further changes the reactivities of 1-Zn 2+ in oxidation and reduction reactions; no reaction occurred upon addition of an oxidantmore » (e.g., cerium(IV) ammonium nitrate (CAN)) to 1-Zn 2+, whereas 1-Zn 2+ coordinating two water molecules, (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2-(OH 2) 2 [1-Zn 2+-(OH 2) 2], releases the O 2 unit in the oxidation reaction. In the reduction reactions, 1-Zn 2+ was converted to its corresponding iron(IV)–oxo species upon addition of a reductant (e.g., a ferrocene derivative), whereas such a reaction occurred at a much slower rate in the case of 1-Zn 2+-(OH 2) 2. Finally, the present results provide the first biomimetic example showing that water molecules at the active sites of metalloenzymes may participate in tuning the redox properties of metal–oxygen intermediates.« less

The effect of Mg dopants on magnetic and structural properties of iron oxide and zinc ferrite thin films

NASA Astrophysics Data System (ADS)

Saritaş, Sevda; Ceviz Sakar, Betul; Kundakci, Mutlu; Yildirim, Muhammet

2018-06-01

Iron oxide thin films have been obtained significant interest as a material that put forwards applications in photovoltaics, gas sensors, biosensors, optoelectronic and especially in spintronics. Iron oxide is one of the considerable interest due to its chemical and thermal stability. Metallic ion dopant influenced superexchange interactions and thus changed the structural, electrical and magnetic properties of the thin film. Mg dopped zinc ferrite (Mg:ZnxFe3-xO4) crystal was used to avoid the damage of Fe3O4 (magnetite) crystal instead of Zn2+ in this study. Because the radius of the Mg2+ ion in the A-site (tetrahedral) is almost equal to that of the replaced Fe3+ ion. Inverse-spinel structure in which oxygen ions (O2-) are arranged to form a face-centered cubic (FCC) lattice where there are two kinds of sublattices, namely, A-site and B-site (octahedral) interstitial sites and in which the super exchange interactions occur. In this study, to increase the saturation of magnetization (Ms) value for iron oxide, inverse-spinal ferrite materials have been prepared, in which the iron oxide was doped by multifarious divalent metallic elements including Zn and Mg. Triple and quaternary; iron oxide and zinc ferrite thin films with Mg metal dopants were grown by using Spray Pyrolysis (SP) technique. The structural, electrical and magnetic properties of Mg dopped iron oxide (Fe2O3) and zinc ferrite (ZnxFe3-xO4) thin films have been investigated. Vibrating Sample Magnetometer (VSM) technique was used to study for the magnetic properties. As a result, we can say that Mg dopped iron oxide thin film has huge diamagnetic and of Mg dopped zinc ferrite thin film has paramagnetic property at bigger magnetic field.

Magnetic and dielectric properties in the UHF frequency band of half-dense Ni-Zn-Co ferrites ceramics with Fe-excess and Fe-deficiency

NASA Astrophysics Data System (ADS)

Mattei, Jean-Luc; Souriou, David; Chevalier, Alexis

2018-02-01

This work investigates electromagnetic properties of half-dense ceramics with compositions Ni0.5Zn0.3Co0.2FeyO4-δ where y = 1.98 (Iron deficient, noted ID) or y = 2.3 (Iron in excess, noted IE). IE and ID materials are obtained by chemical coprecipitation route. The obtained nano-sized powders are pressed and annealed at two temperatures (800 °C, 900 °C), so has to obtain half-massive ceramics. Ferrous and ferric ions coexist in the crystalline structures, but the former in a less extend for ID ferrite. The concomitant influences of Fe2+ and Fe3+ on the dielectric and magnetic losses (ε″/ε‧ and μ″/μ‧, respectively) are considered at frequency up to 6 GHz. The permeability dispersion changes from relaxation-like to resonance-like with the decrease in ferrous ions. In reason of the relaxing-like behavior of Fe2+, and because of a relatively high amount in Fe2+, IE sample shows lower total losses (magnetic and dielectric) than ID sample. These conclusions applied for TA = 900 °C. At frequencies above 700 MHz, the total loss values (IE and ID samples) are prohibitive for antenna downsizing whatever is the firing temperature value (800 °C and 900 °C). Whereas at frequencies below 700 MHz Ni0.5Zn0.3Co0.2Fe2.3O4+δ may leads to better antenna performances than Ni0.5Zn0.3Co0.2Fe1.98O4-δ.

Structural and Magnetic Properties of Transition-Metal-Doped Zn 1-x Fe x O.

PubMed

Abdel-Baset, T A; Fang, Yue-Wen; Anis, B; Duan, Chun-Gang; Abdel-Hafiez, Mahmoud

2016-12-01

The ability to produce high-quality single-phase diluted magnetic semiconductors (DMS) is the driving factor to study DMS for spintronics applications. Fe-doped ZnO was synthesized by using a low-temperature co-precipitation technique producing Zn 1-x Fe x O nanoparticles (x= 0, 0.02, 0.04, 0.06, 0.08, and 0.1). Structural, Raman, density functional calculations, and magnetic studies have been carried out in studying the electronic structure and magnetic properties of Fe-doped ZnO. The results show that Fe atoms are substituted by Zn ions successfully. Due to the small ionic radius of Fe ions compared to that of a Zn ions, the crystal size decreases with an increasing dopant concentration. First-principle calculations indicate that the charge state of iron is Fe (2+) and Fe (3+) with a zinc vacancy or an interstitial oxygen anion, respectively. The calculations predict that the exchange interaction between transition metal ions can switch from the antiferromagnetic coupling into its quasi-degenerate ferromagnetic coupling by external perturbations. This is further supported and explains the observed ferromagnetic bahaviour at magnetic measurements. Magnetic measurements reveal that decreasing particle size increases the ferromagnetism volume fraction. Furthermore, introducing Fe into ZnO induces a strong magnetic moment without any distortion in the geometrical symmetry; it also reveals the ferromagnetic coupling.

In Vitro Iron Availability from Insects and Sirloin Beef.

PubMed

Latunde-Dada, Gladys O; Yang, Wenge; Vera Aviles, Mayra

2016-11-09

Interest in the consumption of insects (entomophagy) as an alternative environmentally sustainable source of protein in the diet of humans has recently witnessed a surge. Knowledge of the nutrient composition and, in particular, the bioavailability of minerals from insects is currently sparse. This study evaluated the availability of Fe, Ca, Cu, Mg, Mn, and Zn from four commonly eaten insects and compared these to sirloin beef. Soluble iron from the samples was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Iron bioavailability was determined using an in vitro simulated peptic-pancreatic digestion, followed by measurement of ferritin (a surrogate marker for iron absorption) in Caco-2 cells. Cricket and sirloin beef had comparably higher levels of Fe, Ca, and Mn than grasshopper, meal, and buffalo worms. However, iron solubility was significantly higher from the insect samples than from beef. The complementation of whole-wheat flour with insect or beef protein resulted in overall decreases in mineral content and iron solubility in the composite mixtures. Collectively, the data show that grasshopper, cricket, and mealworms contain significantly higher chemically available Ca, Cu, Mg, Mn, and Zn than sirloin. However, buffalo worms and sirloin exhibited higher iron bioavailability comparable to that of FeSO 4 . Commonly consumed insect species could be excellent sources of bioavailable iron and could provide the platform for an alternative strategy for increased mineral intake in the diets of humans.

EFFECT OF Mg AND TEMPERATURE ON Fe-Al ALLOY LAYER IN Fe/(Zn-6%Al-x%Mg) SOLID-LIQUID DIFFUSION COUPLES

NASA Astrophysics Data System (ADS)

Liang, Liu; Liu, Ya-Ling; Liu, Ya; Peng, Hao-Ping; Wang, Jian-Hua; Su, Xu-Ping

Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples were kept at various temperatures for different periods of time to investigate the formation and growth of the Fe-Al alloy layer. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) were used to study the constituents and morphology of the Fe-Al alloy layer. It was found that the Fe2Al5Znx phase layer forms close to the iron sheet and the FeAl3Znx phase layer forms near the side of the melted Zn-6%Al-3%Mg in diffusion couples. When the Fe/(Zn-6%Al-3%Mg) diffusion couple is kept at 510∘C for more than 15min, a continuous Fe-Al alloy layer is formed on the interface of the diffusion couple. Among all Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples, the Fe-Al alloy layer on the interface of the Fe/(Zn-6% Al-3% Mg) diffusion couple is the thinnest. The Fe-Al alloy layer forms only when the diffusion temperature is above 475∘. These results show that the Fe-Al alloy layer in Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples is composed of Fe2Al5Znx and FeAl3Znx phase layers. Increasing the diffusing temperature and time period would promote the formation and growth of the Fe-Al alloy layer. When the Mg content in the Fe/(Zn-6%Al-x%Mg) diffusion couples is 3%, the growth of the Fe-Al alloy layer is inhibited. These results may explain why there is no obvious Fe-Al alloy layer formed on the interface of steel with a Zn-6%Al-3%Mg coating.

Evaluation of constitutive iron reductase (AtFRO2) expression on mineral accumulation and distribution in soybean (Glycine max. L)

PubMed Central

Vasconcelos, Marta W.; Clemente, Thomas E.; Grusak, Michael A.

2014-01-01

Iron is an important micronutrient in human and plant nutrition. Adequate iron nutrition during crop production is central for assuring appropriate iron concentrations in the harvestable organs, for human food or animal feed. The whole-plant movement of iron involves several processes, including the reduction of ferric to ferrous iron at several locations throughout the plant, prior to transmembrane trafficking of ferrous iron. In this study, soybean plants that constitutively expressed the AtFRO2 iron reductase gene were analyzed for leaf iron reductase activity, as well as the effect of this transgene’s expression on root, leaf, pod wall, and seed mineral concentrations. High Fe supply, in combination with the constitutive expression of AtFRO2, resulted in significantly higher concentrations of different minerals in roots (K, P, Zn, Ca, Ni, Mg, and Mo), pod walls (Fe, K, P, Cu, and Ni), leaves (Fe, P, Cu, Ca, Ni, and Mg) and seeds (Fe, Zn, Cu, and Ni). Leaf and pod wall iron concentrations increased as much as 500% in transgenic plants, while seed iron concentrations only increased by 10%, suggesting that factors other than leaf and pod wall reductase activity were limiting the translocation of iron to seeds. Protoplasts isolated from transgenic leaves had three-fold higher reductase activity than controls. Expression levels of the iron storage protein, ferritin, were higher in the transgenic leaves than in wild-type, suggesting that the excess iron may be stored as ferritin in the leaves and therefore unavailable for phloem loading and delivery to the seeds. Also, citrate and malate levels in the roots and leaves of transgenic plants were significantly higher than in wild-type, suggesting that organic acid production could be related to the increased accumulation of minerals in roots, leaves, and pod walls, but not in the seeds. All together, these results suggest a more ubiquitous role for the iron reductase in whole-plant mineral accumulation and distribution. PMID:24765096

Calculation of phase diagrams for the FeCl2, PbCl2, and ZnCl2 binary systems by using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Seo, Won-Gap; Matsuura, Hiroyuki; Tsukihashi, Fumitaka

2006-04-01

Recently, molecular dynamics (MD) simulation has been widely employed as a very useful method for the calculation of various physicochemical properties in the molten slags and fluxes. In this study, MD simulation has been applied to calculate the structural, transport, and thermodynamic properties for the FeCl2, PbCl2, and ZnCl2 systems using the Born—Mayer—Huggins type pairwise potential with partial ionic charges. The interatomic potential parameters were determined by fitting the physicochemical properties of iron chloride, lead chloride, and zinc chloride systems with experimentally measured results. The calculated structural, transport, and thermodynamic properties of pure FeCl2, PbCl2, and ZnCl2 showed the same tendency with observed results. Especially, the calculated structural properties of molten ZnCl2 and FeCl2 show the possibility of formation of polymeric network structures based on the ionic complexes of ZnCl{4/2-}, ZnCl{3/-}, FeCl{4/2-}, and FeCl{3/-}, and these calculations have successfully reproduced the measured results. The enthalpy, entropy, and Gibbs energy of mixing for the PbCl2-ZnCl2, FeCl2-PbCl2, and FeCl2-ZnCl2 systems were calculated based on the thermodynamic and structural parameters of each binary system obtained from MD simulation. The phase diagrams of the PbCl2-ZnCl2, FeCl2-PbCl2, and FeCl2-ZnCl2 systems estimated by using the calculated Gibbs energy of mixing reproduced the experimentally measured ones reasonably well.

Phase Equilibria Studies in the System ZnO-``FeO''-Al2O3-CaO-SiO2 Relevant to Imperial Smelting Furnace Slags: Part I

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2010-04-01

The phase equilibria and liquidus temperatures in the system ZnO-“FeO”-Al2O3-CaO-SiO2 in equilibrium with metallic iron have been determined experimentally in the temperature range of 1423 K to 1553 K. The experimental conditions were focused on the composition range relevant to Imperial Smelting Furnace slags. The results are presented in the form of a pseudo-ternary section ZnO-“FeO”-(CaO + SiO2 + Al2O3) in which CaO/SiO2 = 0.93 and (CaO + SiO2)/Al2O3 = 7.0. It was found that wustite and spinel are the major primary phases and that zincite and melilite are also present in the composition range investigated. Wustite (Fe2+,Zn)O and spinel (Fe2+,Zn)O (A1,Fe3+)2O3 solid solutions are formed in this system, and the ZnO concentration in the spinel phase is found to be much greater than in the liquid phase.

Roles of Zinc and Iron on Bone Health in a Rat Model of Osteoporosis

NASA Astrophysics Data System (ADS)

Yan, Danhua

Bone is one of the most vital organs in animals, serving as both structural and protective functions. Remodeling of bone is an important indicator of bone health, and disorders in bone remodeling may lead to bone diseases such as osteoporosis. Osteoporosis increases risk of bone fracture and even death, and much more preferable to be happened in postmenopausal women due to great changes in hormones. Micronutrients, such as Zinc (Zn) and Iron (Fe), would as well influence bone health in different manners. That Zn would promote bone health is widely accepted, for the reasons Zn increases osteoblast cell proliferation and differentiation, inhibits osteoclast cell activities, and forms alkaline phosphatase that does help to maintain bone metabolism. Diseases caused by Fe overload is usually related to osteoporosis. Ferric ion could facilitate osteoclast differentiation, inhibit osteoblast and alkaline phosphatase activities, and interfere with hydroxyapatite crystal growth and depositions. However, changes of concentrations and distributions for Zn and Fe in osteoporotic bones are seldom studied. In this thesis, ovariectomized rat femur bones are used as a model of postmenopausal osteoporosis. Rats from different ages and health conditions are categorized as 6 AM (6-month age matched control), 6 OVX (6-month ovariectomized control), 12 AM (12-month age matched control), 12 OVX (12-month ovariectomized control). The trace elements Zn and Fe is studied through Synchrotron Radiation X-Ray Fluorescence (SRXRF). Elemental maps are used to observe changes in distribution, and further quantitative analysis is used to discover changes in concentration among different animal groups. Both the decrease of Zn and the increase of Fe are significant from healthy to osteoporotic bones (p<0.05). In the meanwhile, accumulation of Zn (p<0.05) and Fe (p>0.1) is also observed over age in healthy groups. Both elements show changes in distribution, that healthy animals present a more even distribution while in OVX groups the tendency of aggregation is observed. These results agree with most of the predictions and add evidence for effects of Zn and Fe on bone health. Hypothesis is further made to rationalize the changing trend observed and explain mechanisms behind.

Sealed reticulocyte ghosts. An experimental model for the study of Fe2+ transport.

PubMed

Núñez, M T; Escobar, A; Ahumada, A; Gonzalez-Sepulveda, M

1992-06-05

Sealed right-side-out reticulocyte ghosts transported and accumulated iron offered as 59Fe(2+)-ascorbate (Km = 1.1 microM). The uptake of iron by ghosts presented the characteristics of a transporter-mediated process: it responded to osmotic challenge, the rate of transport increased when iron was present in the opposing side, and the transport rate showed the temperature dependence typical of membrane-mediated processes. The transport of iron was dependent on an associated influx of Cl- in order to keep electroneutrality. Other transition metals, such as Cu2+, Zn2+, and Co2+, inhibited the transport of Fe2+. The overall characteristics of the system make reticulocyte sealed ghosts a very useful model in determining the basic mechanisms of membrane iron transport.

[The relevance of the trace elements zinc and iron in the milk fever disease of cattle].

PubMed

Heilig, M; Bäuml, D; Fürll, M

2014-01-01

The aim of this study was to analyse the concentrations of Zn and Fe as well as their relationships to metabolic parameters in milk fever cows. A total of 195 Simmental cows, downer cows and clinically healthy control animals were divided into five groups: a) control group (CG, n = 21), b) all cows with milk fever (MF) (n = 174), c) MF cows without additional diseases (n = 145), d) cows with MF and mastitis (n = 10) and e) cows with retained placenta or endometritis (n = 19). Selenium (Se), zinc (Zn), iron (Fe), calcium (Ca), inorganic phosphorus (Pi), tumour necrosis factor α (TNFα), haptoglobin (Hp), antioxidants (Trolox Equivalent Antioxidative Capacity: TEAC), non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), bilirubin, urea, creatinine, glucose, cholesterol, gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were analysed in the blood serum. The concentrations of Zn, Fe, Ca, Pi and TEAC were lower in groups b) to e) whereas Hp was higher than in the CG (p ≤ 0.05). In group c), lower Ca and Pi concentrations were found when compared to groups d) and e) (p ≤ 0.05). In group e), Zn concentrations were significantly lower than in group c) (p ≤ 0.05). Zn was negatively correlated with K (CG) and positively correlated with TEAC, Cu, Mn and Fe (groups b and c) and with Mn (group e) (p ≤ 0.05). Fe was positively correlated with Ca (group c), Pi (group c), K (groups b and c) and Mg (groups b-d) as well as with Zn, Cu and Se (groups b and c) (p ≤ 0.05). In groups b) and c), TNFα was increased and negatively correlated with Fe (p ≤ 0.05). AP activity in groups b) and e) was lower than in the CG (p ≤ 0.05). These results and literature data support the hypothesis that Zn and Fe could be engaged in bone metabolism and be involved in the pathogenesis of MF. The concentrations of Hp and TEAC support this interpretation. Control of the Zn and Fe status of cows and Zn supplementation should be included in the prevention and advanced therapy of MF.

Maternal Cadmium, Iron and Zinc Levels, DNA Methylation and Birth Weight

EPA Science Inventory

BACKGROUND:Cadmium (Cd) is a ubiquitous and environmentally persistent toxic metal that has been implicated in neurotoxicity, carcinogenesis and obesity and essential metals including zinc (Zn) and iron (Fe) may alter these outcomes. However mechanisms underlying these relationsh...

The effect of doping on global lattice properties of magnetite Fe{sub 3-x}Me{sub x}O{sub 4} (Me=Zn, Ti and Al)

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

Kakol, Z.; Owoc, D.; Przewoznik, J.

2012-08-15

X-ray powder diffraction was measured in Fe{sub 3-x}Me{sub x}O{sub 4} (Me=Zn, Ti, Al; x<0.065), in T range 70-300 K to see the effect of different doping on global lattice properties. The experimental results have shown that some lattice properties (e.g., the cell volume) are dopand specific. This can be attributed to the difference in preferential sites occupation by dopants. As confirmed by EXAFS, Zn enters tetrahedral, while Ti octahedral lattice sites, differently affecting crucial octahedral iron positions in the spinel lattice. However, despite this fact, it was found that T dependence of both monoclinic angle and lattice parameters is universalmore » for studied samples above and below the Verwey transition temperature T{sub V}. So, not the iron atoms in octahedral positions individually, but interactions between them are responsible for the Verwey transition character change with doping. - Graphical abstract: A low temperature magnetite cell volume vs. dopants content. Apparently, Zn, Ti and Al atoms have different effect on the global lattice properties at individual temperatures. However, the Verwey transition reacts to dopants in a similar manner, despite the different way the octahedral iron positions are affected. Highlights: Black-Right-Pointing-Pointer We measure powder diffraction and EXAFS on Fe{sub 3-x}Me{sub x}O{sub 4}, Me=Zn, Ti, Al (x<0.065), in T range 70-300 K. Black-Right-Pointing-Pointer XRD: atom-type independent changes of lattice parameters with T. Black-Right-Pointing-Pointer EXAFS: Zn replaces Fe on tetrahedral positions, Ti on octahedral positions. Black-Right-Pointing-Pointer Thus, some secondary interactions between ordering orbitals, not the primary one driving the Verwey transition, control the transition order.« less

Effects of dietary zinc, iron, and copper in layer feed on distribution of these elements in eggs, liver, excreta, soil, and herbage.

PubMed

Skrivan, M; Skrivanová, V; Marounek, M

2005-10-01

An experiment was conducted to evaluate the effect of dietary content and combinations of Zn, Fe, and Cu on deposition of these elements in egg components, liver, and excreta. Excreta were applied as a manure to a lawn, and 3 mo later soil and herbage samples were taken and analyzed. The experiment comprised 144 hens in 8 groups. The basal diet contained Zn, Fe, and Cu at 63.4, 92.8, and 9.0 mg/kg, respectively. It was supplemented with 1, 2, or 3 trace elements (inorganic forms) at 80 mg of Zn/kg, 120 mg of Fe/kg, and 25 mg of Cu/kg. Recovery of Zn, Fe, and Cu in eggs of hens fed the basal diet was 10.7, 9.8, and 4.4% of the alimentary intake, respectively. A Zn-Cu antagonism was observed; deposition of Zn in the yolk was significantly decreased by Cu addition and vice versa (P < 0.01). Supplementation of the basal diet with Fe increased Fe concentration in egg yolk and white by 6.3 and 2.2%, respectively. The combination of Fe with Zn and Cu, however, increased Fe concentration in the yolk and white by 36.7 and 34.9%, respectively (P < 0.01). The enrichment of eggs with the other elements was marginal (Cu) or absent (Zn). Effects of Zn, Fe, and Cu of the basal diet on liver concentrations of these elements were relatively small, and no antagonism between Zn and Cu was apparent. Supplementation of the basal diet with the combination of Zn and Fe, however, significantly decreased hepatic concentration of Cu. On the other hand, Cu supplementation significantly increased Fe concentration in livers of hens fed the Fe-supplemented diet (P < 0.01). Concentrations of Zn, Fe, and Cu in excreta were related to their dietary content. High concentrations of Zn, Fe, and Cu in excreta corresponded with limited deposition of the 3 elements in eggs and liver. Concentrations of Zn, Fe, and Cu in herbage correlated significantly with the supply of these elements by hen excreta into soil. The Zn supplied by hen excreta was more stable than Fe and Cu; thus Zn could accumulate in the soil.

Rosette iron deficiency transcript and microRNA profiling reveals links between copper and iron homeostasis in Arabidopsis thaliana

PubMed Central

Waters, Brian M.; Stein, Ricardo J.

2012-01-01

Iron (Fe) is an essential plant micronutrient, and its deficiency limits plant growth and development on alkaline soils. Under Fe deficiency, plant responses include up-regulation of genes involved in Fe uptake from the soil. However, little is known about shoot responses to Fe deficiency. Using microarrays to probe gene expression in Kas-1 and Tsu-1 ecotypes of Arabidopsis thaliana, and comparison with existing Col-0 data, revealed conserved rosette gene expression responses to Fe deficiency. Fe-regulated genes included known metal homeostasis-related genes, and a number of genes of unknown function. Several genes responded to Fe deficiency in both roots and rosettes. Fe deficiency led to up-regulation of Cu,Zn superoxide dismutase (SOD) genes CSD1 and CSD2, and down-regulation of FeSOD genes FSD1 and FSD2. Eight microRNAs were found to respond to Fe deficiency. Three of these (miR397a, miR398a, and miR398b/c) are known to regulate transcripts of Cu-containing proteins, and were down-regulated by Fe deficiency, suggesting that they could be involved in plant adaptation to Fe limitation. Indeed, Fe deficiency led to accumulation of Cu in rosettes, prior to any detectable decrease in Fe concentration. ccs1 mutants that lack functional Cu,ZnSOD proteins were prone to greater oxidative stress under Fe deficiency, indicating that increased Cu concentration under Fe limitation has an important role in oxidative stress prevention. The present results show that Cu accumulation, microRNA regulation, and associated differential expression of Fe and CuSOD genes are coordinated responses to Fe limitation. PMID:22962679

Iron-based soft magnetic composites with Mn-Zn ferrite nanoparticles coating obtained by sol-gel method

NASA Astrophysics Data System (ADS)

Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

2012-11-01

This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn-Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol-gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn-Zn ferrites. Mn-Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn-Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn-Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability.

Mechanism study on the sulfidation of ZnO with sulfur and iron oxide at high temperature

NASA Astrophysics Data System (ADS)

Han, Junwei; Liu, Wei; Zhang, Tianfu; Xue, Kai; Li, Wenhua; Jiao, Fen; Qin, Wenqing

2017-02-01

The mechanism of ZnO sulfidation with sulfur and iron oxide at high temperatures was studied. The thermodynamic analysis, sulfidation behavior of zinc, phase transformations, morphology changes, and surface properties were investigated by HSC 5.0 combined with FactSage 7.0, ICP, XRD, optical microscopy coupled with SEM-EDS, and XPS. The results indicate that increasing temperature and adding iron oxide can not only improve the sulfidation of ZnO but also promote the formation and growth of ZnS crystals. Fe2O3 captured the sulfur in the initial sulfidation process as iron sulfides, which then acted as the sulfurizing agent in the late period, thus reducing sulfur escape at high temperatures. The addition of carbon can not only enhance the sulfidation but increase sulfur utilization rate and eliminate the generation of SO2. The surfaces of marmatite and synthetic zinc sulfides contain high oxygen due to oxidation and oxygen adsorption. Hydroxyl easily absorbs on the surface of iron-bearing zinc sulfide (Zn1-xFexS). The oxidation of synthetic Zn1-xFexS is easier than marmatite in air.

Mechanism study on the sulfidation of ZnO with sulfur and iron oxide at high temperature

PubMed Central

Han, Junwei; Liu, Wei; Zhang, Tianfu; Xue, Kai; Li, Wenhua; Jiao, Fen; Qin, Wenqing

2017-01-01

The mechanism of ZnO sulfidation with sulfur and iron oxide at high temperatures was studied. The thermodynamic analysis, sulfidation behavior of zinc, phase transformations, morphology changes, and surface properties were investigated by HSC 5.0 combined with FactSage 7.0, ICP, XRD, optical microscopy coupled with SEM-EDS, and XPS. The results indicate that increasing temperature and adding iron oxide can not only improve the sulfidation of ZnO but also promote the formation and growth of ZnS crystals. Fe2O3 captured the sulfur in the initial sulfidation process as iron sulfides, which then acted as the sulfurizing agent in the late period, thus reducing sulfur escape at high temperatures. The addition of carbon can not only enhance the sulfidation but increase sulfur utilization rate and eliminate the generation of SO2. The surfaces of marmatite and synthetic zinc sulfides contain high oxygen due to oxidation and oxygen adsorption. Hydroxyl easily absorbs on the surface of iron-bearing zinc sulfide (Zn1−xFexS). The oxidation of synthetic Zn1−xFexS is easier than marmatite in air. PMID:28186156

Hot-pressed production and laser properties of ZnSe:Fe2+

NASA Astrophysics Data System (ADS)

Avetisov, R. I.; Balabanov, S. S.; Firsov, K. N.; Gavrishchuk, E. M.; Gladilin, A. A.; Ikonnikov, V. B.; Kalinushkin, V. P.; Kazantsev, S. Yu.; Kononov, I. G.; Zykova, M. P.; Mozhevitina, E. N.; Khomyakov, A. V.; Savin, D. V.; Timofeeva, N. A.; Uvarov, O. V.; Avetissov, I. Ch.

2018-06-01

A new approach for fabrication of laser elements in form of plates based on ZnSe:Fe2+ with undoped faces, combining the advantages of hot pressing and diffusion techniques has been proposed. CVD-ZnSe was used as a host material. 1 μm Fe film was deposited by electron-beam technique on one side of the polished CVD-ZnSe plate (20 mm in diameter and 2 mm in thickness). The elements were stacked in contact by iron surfaces, placed in a hot press-mold die, heated under vacuum to 1000 °C, exposed during 60 min with the application of 25 MPa uniaxial pressure. The iron film was dissolved in ZnSe matrix and elements welded together. The samples were subjected to hot isostatic pressing (HIP) during 29 h at 100 MPa argon pressure and 1300 °C. The influence of sintering and HIP processing conditions on local morphology and properties of the interface of welded elements was studied by SEM, TEM and optical microscopy. For all composite elements the lasing was obtained at a pumping by HF-laser at RT with high efficiency around 40%. The proposed technique removes restrictions on the size of laser elements and appears to be very promising for the management of the distribution profile of the doping component.

Mathematical model of zinc absorption: effects of dietary calcium, protein and iron on zinc absorption

PubMed Central

Miller, Leland V.; Krebs, Nancy F.; Hambidge, K. Michael

2013-01-01

A previously described mathematical model of Zn absorption as a function of total daily dietary Zn and phytate was fitted to data from studies in which dietary Ca, Fe and protein were also measured. An analysis of regression residuals indicated statistically significant positive relationships between the residuals and Ca, Fe and protein, suggesting that the presence of any of these dietary components enhances Zn absorption. Based on the hypotheses that (1) Ca and Fe both promote Zn absorption by binding with phytate and thereby making it unavailable for binding Zn and (2) protein enhances the availability of Zn for transporter binding, the model was modified to incorporate these effects. The new model of Zn absorption as a function of dietary Zn, phytate, Ca, Fe and protein was then fitted to the data. The proportion of variation in absorbed Zn explained by the new model was 0·88, an increase from 0·82 with the original model. A reduced version of the model without Fe produced an equally good fit to the data and an improved value for the model selection criterion, demonstrating that when dietary Ca and protein are controlled for, there is no evidence that dietary Fe influences Zn absorption. Regression residuals and testing with additional data supported the validity of the new model. It was concluded that dietary Ca and protein modestly enhanced Zn absorption and Fe had no statistically discernable effect. Furthermore, the model provides a meaningful foundation for efforts to model nutrient interactions in mineral absorption. PMID:22617116

Mathematical model of zinc absorption: effects of dietary calcium, protein and iron on zinc absorption.

PubMed

Miller, Leland V; Krebs, Nancy F; Hambidge, K Michael

2013-02-28

A previously described mathematical model of Zn absorption as a function of total daily dietary Zn and phytate was fitted to data from studies in which dietary Ca, Fe and protein were also measured. An analysis of regression residuals indicated statistically significant positive relationships between the residuals and Ca, Fe and protein, suggesting that the presence of any of these dietary components enhances Zn absorption. Based on the hypotheses that (1) Ca and Fe both promote Zn absorption by binding with phytate and thereby making it unavailable for binding Zn and (2) protein enhances the availability of Zn for transporter binding, the model was modified to incorporate these effects. The new model of Zn absorption as a function of dietary Zn, phytate, Ca, Fe and protein was then fitted to the data. The proportion of variation in absorbed Zn explained by the new model was 0·88, an increase from 0·82 with the original model. A reduced version of the model without Fe produced an equally good fit to the data and an improved value for the model selection criterion, demonstrating that when dietary Ca and protein are controlled for, there is no evidence that dietary Fe influences Zn absorption. Regression residuals and testing with additional data supported the validity of the new model. It was concluded that dietary Ca and protein modestly enhanced Zn absorption and Fe had no statistically discernable effect. Furthermore, the model provides a meaningful foundation for efforts to model nutrient interactions in mineral absorption.

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

Lee, Yong-Min; Bang, Suhee; Yoon, Heejung

Here we report redox-inactive metal ions play important roles in tuning chemical properties of metal–oxygen intermediates. We describe the effect of water molecules on the redox properties of a nonheme iron(III)–peroxo complex binding redox-inactive metal ions. The coordination of two water molecules to a Zn 2+ ion in (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2 (1-Zn 2+) decreases the Lewis acidity of the Zn 2+ ion, resulting in the decrease of the one-electron oxidation and reduction potentials of 1-Zn 2+. This further changes the reactivities of 1-Zn 2+ in oxidation and reduction reactions; no reaction occurred upon addition of an oxidantmore » (e.g., cerium(IV) ammonium nitrate (CAN)) to 1-Zn 2+, whereas 1-Zn 2+ coordinating two water molecules, (TMC)Fe III-(O 2)-Zn(CF 3SO 3) 2-(OH 2) 2 [1-Zn 2+-(OH 2) 2], releases the O 2 unit in the oxidation reaction. In the reduction reactions, 1-Zn 2+ was converted to its corresponding iron(IV)–oxo species upon addition of a reductant (e.g., a ferrocene derivative), whereas such a reaction occurred at a much slower rate in the case of 1-Zn 2+-(OH 2) 2. Finally, the present results provide the first biomimetic example showing that water molecules at the active sites of metalloenzymes may participate in tuning the redox properties of metal–oxygen intermediates.« less

Application of Zero-Valent Iron Nanoparticles for the Removal of Aqueous Zinc Ions under Various Experimental Conditions

PubMed Central

Liang, Wen; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei

2014-01-01

Application of zero-valent iron nanoparticles (nZVI) for Zn2+ removal and its mechanism were discussed. It demonstrated that the uptake of Zn2+ by nZVI was efficient. With the solids concentration of 1 g/L nZVI, more than 85% of Zn2+ could be removed within 2 h. The pH value and dissolved oxygen (DO) were the important factors of Zn2+ removal by nZVI. The DO enhanced the removal efficiency of Zn2+. Under the oxygen-contained condition, oxygen corrosion gave the nZVI surface a shell of iron (oxy)hydroxide, which could show high adsorption affinity. The removal efficiency of Zn2+ increased with the increasing of the pH. Acidic condition reduced the removal efficiency of Zn2+ by nZVI because the existing H+ inhibited the formation of iron (oxy)hydroxide. Adsorption and co-precipitation were the most likely mechanism of Zn2+ removal by nZVI. The FeOOH-shell could enhance the adsorption efficiency of nZVI. The removal efficiency and selectivity of nZVI particles for Zn2+ were higher than Cd2+. Furthermore, a continuous flow reactor for engineering application of nZVI was designed and exhibited high removal efficiency for Zn2+. PMID:24416439

Effects of Al2O3 and CaO/SiO2 Ratio on Phase Equilbria in the ZnO-"FeO"-Al2O3-CaO-SiO2 System in Equilibrium with Metallic Iron

NASA Astrophysics Data System (ADS)

Zhao, Baojun; Hayes, Peter C.; Jak, Evgueni

2011-02-01

The phase equilibria and liquidus temperatures in the ZnO-"FeO"-Al2O3-CaO-SiO2 system in equilibrium with metallic iron have been determined experimentally in the temperature range 1383 K to 1573 K (1150 °C to 1300 °C). The experimental conditions were selected to characterize lead blast furnace and imperial smelting furnace slags. The results are presented in a form of pseudoternary sections ZnO-"FeO"-(Al2O3 + CaO + SiO2) with fixed CaO/SiO2 and (CaO + SiO2)/Al2O3 ratios. It was found that wustite and spinel are the major primary phases in the composition range investigated. Effects of Al2O3 concentration as well as the CaO/SiO2 ratio on the primary phase field, the liquidus temperature, and the partitioning of ZnO between liquid and solid phases have been discussed for zinc-containing slags.

Magnetic moment in single crystalline BaFe2-xZnxAs2

NASA Astrophysics Data System (ADS)

Guo, Yanfeng; Wang, Xia; Li, Jun; Yamaura, Kazunari; Takayama-Muromachi, Eiji

2012-02-01

Nature of the magnetism for iron-based superconductors (FeSCs) has been actively studied since the discovery of this new family of compounds in 2008, largely owing to its significance for interpreting the paring mechanism. The approach through impurity substitution to shed light into this issue is always one of major ways. The substitution shows distinct responses to species of impurities, where partially replacement of Fe in parent FeSCs with a variety of d-metals like Co, Ni Ru, Rh, Pd, Ir, and Pt generally results in superconductivity, while recent progress in Zn doped FeSCs gives rather contrary result, where Zn severely degenerates the TC. Herein we show the magnetic and electrical studies on BaFe2-xZnxAs2 single crystals. Nonmagnetic Zn doping progressively suppresses the SDW without resulting in superconductivity, while it alternatively develops the spin-glass state, possibly suggestive of local magnetic moment around the Fe sites induced by Zn. The characterizations by X-ray diffraction, magnetic and electrical transport properties, specific heat capacity, and Hall coefficient have been done and the results will be discussed in detail.

Redox inactive metal ion triggered N-dealkylation by an iron catalyst with dioxygen activation: a lesson from lipoxygenases.

PubMed

Zhang, Jisheng; Wang, Yujuan; Luo, Nengchao; Chen, Zhuqi; Wu, Kangbing; Yin, Guochuan

2015-06-07

Utilization of dioxygen as the terminal oxidant at ambient temperature is always a challenge in redox chemistry, because it is hard to oxidize a stable redox metal ion like iron(III) to its high oxidation state to initialize the catalytic cycle. Inspired by the dioxygenation and co-oxidase activity of lipoxygenases, herein, we introduce an alternative protocol to activate the sluggish iron(III) species with non-redox metal ions, which can promote its oxidizing power to facilitate substrate oxidation with dioxygen, thus initializing the catalytic cycle. In oxidations of N,N-dimethylaniline and its analogues, adding Zn(OTf)2 to the [Fe(TPA)Cl2]Cl catalyst can trigger the amine oxidation with dioxygen, whereas [Fe(TPA)Cl2]Cl alone is very sluggish. In stoichiometric oxidations, it has also been confirmed that the presence of Zn(OTf)2 can apparently improve the electron transfer capability of the [Fe(TPA)Cl2]Cl complex. Experiments using different types of substrates as trapping reagents disclosed that the iron(IV) species does not occur in the catalytic cycle, suggesting that oxidation of amines is initialized by electron transfer rather than hydrogen abstraction. Combined experiments from UV-Vis, high resolution mass spectrometry, electrochemistry, EPR and oxidation kinetics support that the improved electron transfer ability of iron(III) species originates from its interaction with added Lewis acids like Zn(2+) through a plausible chloride or OTf(-) bridge, which has promoted the redox potential of iron(III) species. The amine oxidation mechanism was also discussed based on the available data, which resembles the co-oxidase activity of lipoxygenases in oxidative dealkylation of xenobiotic metabolisms where an external electron donor is not essential for dioxygen activation.

Zinc and selenium accumulation and their effect on iron bioavailability in common bean seeds.

PubMed

de Figueiredo, Marislaine A; Boldrin, Paulo F; Hart, Jonathan J; de Andrade, Messias J B; Guilherme, Luiz R G; Glahn, Raymond P; Li, Li

2017-02-01

Common beans (Phaseolus vulgaris) are the most important legume crops. They represent a major source of micronutrients and a target for essential trace mineral enhancement (i.e. biofortification). To investigate mineral accumulation during seed maturation and to examine whether it is possible to biofortify seeds with multi-micronutrients without affecting mineral bioavailability, three common bean cultivars were treated independently with zinc (Zn) and selenium (Se), the two critical micronutrients that can be effectively enhanced via fertilization. The seed mineral concentrations during seed maturation and the seed Fe bioavailability were analyzed. Common bean seeds were found to respond positively to Zn and Se treatments in accumulating these micronutrients. While the seed pods showed a decrease in Zn and Se along with Fe content during pod development, the seeds maintained relatively constant mineral concentrations during seed maturation. Selenium treatment had minimal effect on the seed accumulation of phytic acid and polyphenols, the compounds affecting Fe bioavailability. Zinc treatment reduced phytic acid level, but did not dramatically affect the concentrations of total polyphenols. Iron bioavailability was found not to be greatly affected in seeds biofortified with Se and Zn. In contrast, the inhibitory polyphenol compounds in the black bean profoundly reduced Fe bioavailability. These results provide valuable information for Se and Zn enhancement in common bean seeds and suggest the possibility to biofortify with these essential nutrients without greatly affecting mineral bioavailability to increase the food quality of common bean seeds. Published by Elsevier Masson SAS.

Structures of E. coli peptide deformylase bound to formate: insight into the preference for Fe2+ over Zn2+ as the active site metal.

PubMed

Jain, Rinku; Hao, Bing; Liu, Ren-Peng; Chan, Michael K

2005-04-06

E. coli peptide deformylase (PDF) catalyzes the deformylation of nascent polypeptides generated during protein synthesis. While PDF was originally thought to be a zinc enzyme, subsequent studies revealed that the active site metal is iron. In an attempt to understand this unusual metal preference, high-resolution structures of Fe-, Co-, and Zn-PDF were determined in complex with its deformylation product, formate. In all three structures, the formate ion binds the metal and forms hydrogen-bonding interactions with the backbone nitrogen of Leu91, the amide side chain of Gln50, and the carboxylate side chain of Glu133. One key difference, however, is how the formate binds the metal. In Fe-PDF and Co-PDF, formate binds in a bidentate fashion, while in Zn-PDF, it binds in a monodentate fashion. Importantly, these structural results provide the first clues into the origins of PDF's metal-dependent activity differences. On the basis of these structures, we propose that the basis for the higher activity of Fe-PDF stems from the better ability of iron to bind and activate the tetrahedral transition state required for cleavage of the N-terminal formyl group.

Facile synthesis of p-type Zn-doped α-Fe2O3 films for solar water splitting

NASA Astrophysics Data System (ADS)

Kuo, Chun-Lin; Hsu, Yu-Kuei; Lin, Yan-Gu

2014-10-01

A facile and simple fabrication of Zn-doped α-Fe2O3 thin films as a photocathode for solar hydrogen generation was proposed in this report. Transparent Zn-doped α-Fe2O3 films were prepared by a deposition-annealing (DA) process using nontoxic iron(III) chloride as the Fe precursor and zinc chloride as a acceptor dopant, followed by annealing at 550 °C in air. In terms of the structural examination of as-grown samples, X-ray diffraction analysis demonstrated an increase in the lattice parameters of Zn incorporated in Fe2O3 by substituting Fe in the host lattice. No second phase was determined, indicating no phase separation in the ternary materials. Energy dispersive spectroscopy results demonstrated that Zn, Fe, and O elements existed in the deposits. Furthermore, impedance measurements show that the Zn-dopant serves as an hole acceptor and increases the acceptor concentration by increasing concentration of zinc precursor. Significantly, the photoelectrochemical measurements exhibited remarkable cathodic current, corresponding to the reduction reaction of hydrogen. Finally, the optimum photocurrent can be achieved by controlled variation of the Fe and Zni precursor concentration, annealing conditions, and the number of DA cycles. According to our investigation, the understandings of morphology effect on PEC activity give the blueprint for materials design in the application of solar hydrogen.

Advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness

USDA-ARS?s Scientific Manuscript database

Biofortification aims to improve the micronutrient concentration of staple food crops through the best practices of breeding and modern biotechnology. However, increased zinc and iron concentrations in food crops may not always translate into proportional increases in absorbed zinc (Zn) and iron (Fe...

Theranostic multimodular potential of zinc-doped ferrite-saturated metal-binding protein-loaded novel nanocapsules in cancers

PubMed Central

Kamalapuram, Sishir K; Kanwar, Rupinder K; Roy, Kislay; Chaudhary, Rajneesh; Sehgal, Rakesh; Kanwar, Jagat R

2016-01-01

The present study successfully developed orally deliverable multimodular zinc (Zn) iron oxide (Fe3O4)-saturated bovine lactoferrin (bLf)-loaded polymeric nanocapsules (NCs), and evaluated their theranostic potential (antitumor efficacy, magnetophotothermal efficacy and imaging capability) in an in vivo human xenograft CpG-island methylator phenotype (CIMP)-1+/CIMP2−/chromosome instability-positive colonic adenocarcinoma (Caco2) and claudin-low, triple-negative (ER−/PR−/HER2−; MDA-MB-231) breast cancer model. Mice fed orally on the Zn-Fe-bLf NC diet showed downregulation in tumor volume and complete regression in tumor volume after 45 days of feeding. In human xenograft colon cancer, vehicle-control NC diet-group (n=5) mice showed a tumor volume of 52.28±11.55 mm3, and Zn-Fe-bLf NC diet (n=5)-treated mice had a tumor-volume of 0.10±0.073 mm3. In the human xenograft breast cancer model, Zn-Fe-bLf NC diet (n=5)-treated mice showed a tumor volume of 0.051±0.062 mm3 within 40 days of feeding. Live mouse imaging conducted by near-infrared fluorescence imaging of Zn-Fe-bLf NCs showed tumor site-specific localization and regression of colon and breast tumor volume. Ex vivo fluorescence-imaging analysis of the vital organs of mice exhibited sparse localization patterns of Zn-Fe-bLf NCs and also confirmed tumor-specific selective localization patterns of Zn-Fe-bLf NCs. Dual imaging using magnetic resonance imaging and computerized tomography scans revealed an unprecedented theranostic ability of the Zn-Fe-bLf NCs. These observations warrant consideration of multimodular Zn-Fe-bLf NCs for real-time cancer imaging and simultaneous cancer-targeted therapy. PMID:27099495

Theoretical study of the characteristics of a continuous wave iron-doped ZnSe laser

NASA Astrophysics Data System (ADS)

Pan, Qikun; Chen, Fei; Xie, Jijiang; Wang, Chunrui; He, Yang; Yu, Deyang; Zhang, Kuo

2018-03-01

A theoretical model describing the dynamic process of a continuous-wave Fe2+:ZnSe laser is presented. The influence of some of the operating parameters on the output characteristics of an Fe2+:ZnSe laser is studied in detail. The results indicate that the temperature rise of the Fe2+:ZnSe crystal is significant with the use of a high power pump laser, especially for a high doped concentration of crystal. The optimal crystal length increases with decreasing the doped concentration of crystal, so an Fe2+:ZnSe crystal with simultaneous doping during growth is an attractive choice, which usually has a low doped concentration and long length. The laser pumping threshold is almost stable at low temperatures, but increases exponentially with a working temperature in the range of 180 K to room temperature. The main reason for this phenomenon is the short upper level lifetime and serious thermal temperature rise when the working temperature is higher than 180 K. The calculated optimum output mirror transmittance is about 35% and the performance of a continuous-wave Fe2+:ZnSe laser is more efficient at a lower operating temperature.

Effect of different iron compounds on rheological and technological parameters as well as bioaccessibility of minerals in whole wheat bread.

PubMed

Rebellato, Ana Paula; Bussi, Jéssica; Silva, Joyce Grazielle Siqueira; Greiner, Ralf; Steel, Caroline Joy; Pallone, Juliana Azevedo Lima

2017-04-01

This study aimed at investigating the effect of iron compounds used in whole wheat flour (WWF) fortification, both on rheological properties of the dough and on bread technological quality. Furthermore, bioaccessibility of iron (Fe), zinc (Zn) and calcium (Ca) in the final breads was determined. Rheological properties (mainly dough development time, stability, mixing tolerance index, resistance to extension and ratio number) of the dough and the technological quality of bread (mainly oven spring and cut opening) were altered. However, producing roll breads fortified with different iron compounds was still possible. NaFeEDTA (ferric sodium ethylene diamine tetra acetic acid) proved to be the most effective iron compound in the fortification of WWF, since it presented the highest levels of solubility (44.80%) and dialysability (46.14%), followed by microencapsulated ferrous fumarate (FFm). On the other hand, the microencapsulated ferrous sulfate (FSm) and reduced iron presented the lowest solubility (5.40 and 18.30%, respectively) and dialysability (33.12 and 31.79%, respectively). Zn dialysis was positively influenced by NaFeEDTA, FSm, and ferrous fumarate. As for Ca, dialysis was positively influenced by FSm and negatively influenced by FFm. The data indicated that there is a competitive interaction for the absorption of these minerals in whole wheat roll breads, but all studied minerals can be considered bioaccessible. Copyright © 2017 Elsevier Ltd. All rights reserved.

Is there a strategy I iron uptake mechanism in maize?

PubMed

Li, Suzhen; Zhou, Xiaojin; Chen, Jingtang; Chen, Rumei

2018-04-03

Iron is a metal micronutrient that is essential for plant growth and development. Graminaceous and nongraminaceous plants have evolved different mechanisms to mediate Fe uptake. Generally, strategy I is used by nongraminaceous plants like Arabidopsis, while graminaceous plants, such as rice, barley, and maize, are considered to use strategy II Fe uptake. Upon the functional characterization of OsIRT1 and OsIRT2 in rice, it was suggested that rice, as an exceptional graminaceous plant, utilizes both strategy I and strategy II Fe uptake systems. Similarly, ZmIRT1 and ZmZIP3 were identified as functional zinc and iron transporters in the maize genome, along with the determination of several genes encoding Zn and Fe transporters, raising the possibility that strategy I Fe uptake also occurs in maize. This mini-review integrates previous reports and recent evidence to obtain a better understanding of the mechanisms of Fe uptake in maize.

Efficient metal adsorption and microbial reduction from Rawal Lake wastewater using metal nanoparticle coated cotton.

PubMed

Ali, Attarad; Gul, Ayesha; Mannan, Abdul; Zia, Muhammad

2018-05-17

This study was designed to investigate removal of toxic metals and reduction of bacterial count from Rawal Lake wastewater with novel nanocomposite sorbents. Iron, zinc and silver oxide nanoparticles (NPs) were attached on cotton. The nanocomposites (iron NPs on cotton (FeCt), zinc NPs on cotton (ZnCt) and silver NPs on cotton (AgCt)) were characterized by FTIR, XRD and SEM, which showed successful adsorption of 10-30 nm size nanoparticles. Batch experiments were performed to determine the adsorption capacity of nanocomposite for metal removal. All the three adsorbents demonstrated 100% adsorption efficiency for Ag + , Co 2+ , Fe 3+ , Zn 2+ and Cu 2+ whereas less adsorption for Cd 2+ and Cr 3+ . The maximum adsorbance (qe) was exhibited by Co 2+ on ZnCt, FeCt and AgCt as 125.0, 111.1 and 100.0 mg g -1 , respectively. The efficiency of adsorbents for metal ions sorption was found as AgCt > ZnCt > FeCt while the order of adsorption for metals was observed as Fe 3+  > Co 2+  > Zn 2+  > Cu 2+  > Ag +  > Cr 3+  > Cd 2 + . The adsorption mechanism mostly follow Langmuir isotherm and pseudo-second order kinetic model. The maximum microbial reduction was exhibited by AgCt followed by ZnCt and FeCt. The microbes were further processed for staining and biochemical characteristics to evaluate resistance and sensitive microbes. The study concludes that the NPs doped on cotton can be effectively used for adsorption of heavy metals and reduction of microbial count from natural wastewater making it valuable for human consumption. In addition, the nanoparticles impregnated cotton can be efficiently used in water filtration plants. Copyright © 2018. Published by Elsevier B.V.

The AMBRE project: Iron-peak elements in the solar neighbourhood

NASA Astrophysics Data System (ADS)

Mikolaitis, Š.; de Laverny, P.; Recio-Blanco, A.; Hill, V.; Worley, C. C.; de Pascale, M.

2017-04-01

Context. The pattern of chemical abundance ratios in stellar populations of the Milky Way is a fingerprint of the Galactic chemical history. In order to interpret such chemical fossils of Galactic archaeology, chemical evolution models have to be developed. However, despite the complex physics included in the most recent models, significant discrepancies between models and observations are widely encountered. Aims: The aim of this paper is to characterise the abundance patterns of five iron-peak elements (Mn, Fe, Ni, Cu, and Zn) for which the stellar origin and chemical evolution are still debated. Methods: We automatically derived iron peak (Mn, Fe, Ni, Cu, and Zn) and α element (Mg) chemical abundances for 4666 stars, adopting classical LTE spectral synthesis and 1D atmospheric models. Our observational data collection is composed of high-resolution, high signal-to-noise ratios HARPS and FEROS spectra, which were previously parametrised by the AMBRE project. Results: We used the bimodal distribution of the magnesium-to-iron abundance ratios to chemically classify our sample stars into different Galactic substructures: thin disc, metal-poor and high-α metal rich, high-α, and low-α metal-poor populations. Both high-α and low-α metal-poor populations are fully distinct in Mg, Cu, and Zn, but these substructures are statistically indistinguishable in Mn and Ni. Thin disc trends of [Ni/Fe] and [Cu/Fe] are very similar and show a small increase at supersolar metallicities. Also, both thin and thick disc trends of Ni and Cu are very similar and indistinguishable. Yet, Mn looks very different from Ni and Cu. [Mn/Fe] trends of thin and thick discs actually have noticeable differences: the thin disc is slightly Mn richer than the thick disc. The [Zn/Fe] trends look very similar to those of [α/Fe] trends. The typical dispersion of results in both discs is low (≈0.05 dex for [Mg, Mn, and Cu/Fe]) and is even much lower for [Ni/Fe] (≈0.035 dex). Conclusions: It is clearly demonstrated that Zn is an α-like element and could be used to separate thin and thick disc stars. Moreover, we show that the [Mn/Mg] ratio could also be a very good tool for tagging Galactic substructures. From the comparison with Galactic chemical evolutionary models, we conclude that some recent models can partially reproduce the observed Mg, Zn, and, Cu behaviours in thin and thick discs and metal-poor sequences. Models mostly fail to reproduce Mn and Ni in all metallicity domains, however, models adopting yields normalised from solar chemical properties reproduce Mn and Ni better, suggesting that there is still a lack of realistic theoretical yields of some iron-peak elements. The very low scatter (≈0.05 dex) in thin and thick disc sequences could provide an observational constrain for Galactic evolutionary models that study the efficiency of stellar radial migration. Based on observations collected at ESO telescopes under the AMBRE programme. Full Table 5 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/600/A22

Evaluation of serum levels of essential trace elements in patients with pulmonary tuberculosis before and after treatment by age and gender.

PubMed

Pourfallah, F; Javadian, S; Zamani, Z; Saghiri, R; Sadeghi, S; Zarea, B; Mirkhani, F; Fatemi, N; Kordi, T

2011-05-15

The purpose of this study was to evaluate the levels of Zinc, Copper, Iron and Copper/Zinc ratio in the serum of adult patients with pulmonary tuberculosis in Iran. Serum levels of Zinc and Copper were determined by flame atomic absorption spectrophotometer and scrum iron concentration was measured by using an Auto Analyzer. The study group consisted of 50 pulmonary tuberculosis patients before treatment and after 6 months of anti-tubercular therapy. Levels of scrum Zn (p < 0.001) and Fe (p < 0.001) in TB patients were significantly increased after 6 months of anti-tubercular therapy. However, serum Cu concentration (p < 0.01) and Cu/Zn ratio (p < 0.05) were decreased after 6 months of anti-tubercular therapy. Some studies indicated a strong association of Zn, Cu, Fe and the Cu/Zn ratio with TB. In this study, we found remarkable change in Cu/Zn ratio. Some researchers mentioned that serum Cu/Zn ratio could be used as an important laboratory marker for diagnosis and treatment of tuberculosis. They also mentioned that trace element levels must be closely monitored during the process of disease.

Degradation of 1,2,3-trichloropropane (TCP): hydrolysis, elimination, and reduction by iron and zinc.

PubMed

Sarathy, Vaishnavi; Salter, Alexandra J; Nurmi, James T; O'Brien Johnson, Graham; Johnson, Richard L; Tratnyek, Paul G

2010-01-15

1,2,3-Trichloropropane (TCP) is an emerging contaminant because of increased recognition of its occurrence in groundwater, potential carcinogenicity, and resistance to natural attenuation. The physical and chemical properties of TCP make it difficult to remediate, with all conventional options being relatively slow or inefficient. Treatments that result in alkaline conditions (e.g., permeable reactive barriers containing zerovalent iron) favor base-catalyzed hydrolysis of TCP, but high temperature (e.g., conditions of in situ thermal remediation) is necessary for this reaction to be significant. Common reductants (sulfide, ferrous iron adsorbed to iron oxides, and most forms of construction-grade or nano-Fe(0)) produce insignificant rates of reductive dechlorination of TCP. Quantifiable rates of TCP reduction were obtained with several types of activated nano-Fe(0), but the surface area normalized rate contants (k(SA)) for these reactions were lower than is generally considered useful for in situ remediation applications (10(-4) L m(-2) h(-1)). Much faster rates of degradation of TCP were obtained with granular Zn(0), (k(SA) = 10(-3) - 10(-2) L m(-2) h(-1)) and potentially problematic dechlorination intermediates (1,2- or 1,3-dichloropropane, 3-chloro-1-propene) were not detected. The advantages of Zn(0) over Fe(0) are somewhat peculiar to TCP and may suggest a practical application for Zn(0) even though it has not found favor for remediation of contamination with other chlorinated solvents.

Interactions between microbial iron reduction and metal geochemistry: effect of redox cycling on transition metal speciation in iron bearing sediments.

PubMed

Cooper, D Craig; Picardal, Flynn F; Coby, Aaron J

2006-03-15

Microbial iron reduction is an important biogeochemical process that can affect metal geochemistry in sediments through direct and indirect mechanisms. With respectto Fe(III) (hydr)oxides bearing sorbed divalent metals, recent reports have indicated that (1) microbial reduction of goethite/ferrihydrite mixtures preferentially removes ferrihydrite, (2) this process can incorporate previously sorbed Zn(II) into an authigenic crystalline phase that is insoluble in 0.5 M HCl, (3) this new phase is probably goethite, and (4) the presence of nonreducible minerals can inhibit this transformation. This study demonstrates that a range of sorbed transition metals can be selectively sequestered into a 0.5 M HCl insoluble phase and that the process can be stimulated through sequential steps of microbial iron reduction and air oxidation. Microbial reduction experiments with divalent Cd, Co, Mn, Ni, Pb, and Zn indicate that all metals save Mn experienced some sequestration, with the degree of metal incorporation into the 0.5 M HCl insoluble phase correlating positively with crystalline ionic radius at coordination number = 6. Redox cycling experiments with Zn adsorbed to synthetic goethite/ferrihydrite or iron-bearing natural sediments indicate that redox cycling from iron reducing to iron oxidizing conditions sequesters more Zn within authigenic minerals than microbial iron reduction alone. In addition, the process is more effective in goethite/ferrihydrite mixtures than in iron-bearing natural sediments. Microbial reduction alone resulted in a -3x increase in 0.5 M HCl insoluble Zn and increased aqueous Zn (Zn-aq) in goethite/ferrihydrite, but did not significantly affect Zn speciation in natural sediments. Redox cycling enhanced the Zn sequestration by approximately 12% in both goethite/ferrihydrite and natural sediments and reduced Zn-aq to levels equal to the uninoculated control in goethite/ferrihydrite and less than the uninoculated control in natural sediments. These data suggest that in situ redox cycling may serve as an effective method for

On the early fate of hydrothermal iron at deep-sea vents: A reassessment after in situ filtration

NASA Astrophysics Data System (ADS)

Waeles, M.; Cotte, L.; Pernet-Coudrier, B.; Chavagnac, V.; Cathalot, C.; Leleu, T.; Laës-Huon, A.; Perhirin, A.; Riso, R. D.; Sarradin, P.-M.

2017-05-01

Deep-sea hydrothermal venting is now recognized as a major source of iron (Fe), an essential trace element that controls marine productivity. However, the reactions occurring during dispersal from buoyant plumes to neutrally buoyant hydrothermal plumes are still poorly constrained. Here we report for the first time on the dissolved-particulate partition of Fe after in situ filtration at the early stage of mixing at different hydrothermal discharges, i.e., Lucky Strike (37°N), TAG (26°N), and Snakepit (23°N) on the Mid-Atlantic Ridge. We found that hydrothermal iron is almost completely preserved (>90%) in the dissolved fraction, arguing for low iron-bearing sulfide precipitation of iron in basalt-hosted systems with low Fe:H2S ratios. This result can only be explained by a kinetically limited formation of pyrite. The small part of Fe being precipitated as sulfides in the mixing gradient (<10%) is restricted to the inclusion of Fe in minerals of high Cu and Zn content. We also show that secondary venting is a source of Fe-depleted hydrothermal solutions. These results provide new constrains on Fe fluxes from hydrothermal venting.

Molecular layers of ZnPc and FePc on Au(111) surface: Charge transfer and chemical interaction

NASA Astrophysics Data System (ADS)

Ahmadi, Sareh; Shariati, M. Nina; Yu, Shun; Göthelid, Mats

2012-08-01

We have studied zinc phthalocyanine (ZnPc) and iron phthalocyanine (FePc) thick films and monolayers on Au(111) using photoelectron spectroscopy and x-ray absorption spectroscopy. Both molecules are adsorbed flat on the surface at monolayer. ZnPc keeps this orientation in all investigated coverages, whereas FePc molecules stand up in the thick film. The stronger inter-molecular interaction of FePc molecules leads to change of orientation, as well as higher conductivity in FePc layer in comparison with ZnPc, which is reflected in thickness-dependent differences in core-level shifts. Work function changes indicate that both molecules donate charge to Au; through the π-system. However, the Fe3d derived lowest unoccupied molecular orbital receives charge from the substrate when forming an interface state at the Fermi level. Thus, the central atom plays an important role in mediating the charge, but the charge transfer as a whole is a balance between the two different charge transfer channels; π-system and the central atom.

Inferring episodic atmospheric iron fluxes in the Western South Atlantic

NASA Astrophysics Data System (ADS)

Evangelista, Heitor; Maldonado, Juan; dos Santos, Elaine A.; Godoi, Ricardo H. M.; Garcia, Carlos A. E.; Garcia, Virginia M. T.; Jonhson, Erling; Dias da Cunha, Kenya; Leite, Carlos Barros; Van Grieken, René; Van Meel, Katleen; Makarovska, Yaroslava; Gaiero, Diego M.

2010-02-01

Iron (Fe) and other trace elements such as Zn, Mn, Ni and Cu are known as key-factors in marine biogeochemical cycles. It is believed that ocean primary productivity blooms in iron deficient regions can be triggered by iron in aeolian dust. Up to now, scarce aerosol elemental composition, based on measurements over sea at the Western South Atlantic (WSA), exist. An association between the Patagonian semi-desert dust/Fe and chlorophyll-a variability at the Argentinean continental shelf is essentially inferred from models. We present here experimental data of Fe enriched aerosols over the WSA between latitudes 22°S-62°S, during 4 oceanographic campaigns between 2002 and 2005. These data allowed inferring the atmospheric Fe flux onto different latitudinal bands which varied from 30.4 to 1688 nmolFe m -2 day -1 (October 29th-November 15th, 2003); 5.83-1586 nmolFe m -2 day -1 (February 15th-March 6th, 2004) and 4.73-586 nmolFe m -2 day -1(October 21st-November 5th, 2005).

Efficacy of a microencapsulated iron pyrophosphate-fortified fruit juice: a randomised, double-blind, placebo-controlled study in Spanish iron-deficient women.

PubMed

Blanco-Rojo, Ruth; Pérez-Granados, Ana M; Toxqui, Laura; González-Vizcayno, Carmen; Delgado, Marco A; Vaquero, M Pilar

2011-06-01

Fe-deficiency anaemia is a worldwide health problem. We studied the influence of consuming an Fe-fortified fruit juice on Fe status in menstruating women. A randomised, double-blind, placebo-controlled study of 16 weeks of duration was performed. Subjects were randomised into two groups: the P group (n 58) or the F group (n 64), and consumed, as a supplement to their usual diet, 500 ml/d of a placebo fruit juice or an Fe-fortified fruit juice, respectively. The Fe-fortified fruit juice, containing microencapsulated iron pyrophosphate, provided 18 mg Fe/d (100 % of the RDA). At baseline and monthly, dietary intake, body weight and Fe parameters were determined: total erythrocytes, haematocrit, mean corpuscular volume (MCV), red blood cell distribution width (RDW), Hb, serum Fe, serum ferritin, serum transferrin, transferrin saturation, soluble transferrin receptor (sTfR) and zinc protoporphyrin (ZnPP). The fruit juice consumption involved increased intake of carbohydrates and vitamin C, and increased BMI within normal limits. Ferritin was higher in the F group after week 4 (P < 0·05) and became 80 % higher than in the P group after week 16 (P < 0·001), and transferrin decreased in the F group compared with the P group after week 4 (P < 0·001). RDW was higher at weeks 4 and 8 in the F group compared with the P group (P < 0·05). Transferrin saturation increased after week 8, and haematocrit, MCV and Hb increased after week 12, in the F group compared with the P group. Serum Fe did not change. sTfR and ZnPP decreased in the F group at week 16 (P < 0·05). Iron pyrophosphate-fortified fruit juice improves Fe status and may be used to prevent Fe-deficiency anaemia.

Inert anode containing oxides of nickel, iron and zinc useful for the electrolytic production of metals

DOEpatents

Ray, Siba P.; Weirauch, Jr., Douglas A.; Liu, Xinghua

2002-01-01

An inert anode for the electrolytic production of metals such as aluminum is disclosed. The inert anode includes a ceramic oxide material preferably made from NiO, Fe.sub.2 O.sub.3 and ZnO. The inert anode composition may comprise the following mole fractions of NiO, Fe.sub.2 O.sub.3 and ZnO: 0.2 to 0.99 NiO; 0.0001 to 0.8 Fe.sub.2 O.sub.3 ; and 0.0001 to 0.3 ZnO. The inert anode may optionally include other oxides and/or at least one metal phase, such as Cu, Ag, Pd, Pt, Au, Rh, Ru, Ir and/or Os. The Ni--Fe--Co--O ceramic material exhibits very low solubility in Hall cell baths used to produce aluminum.

Mössbauer spectroscopy of ZnxMg1-x Fe2O4 (0 ≤ x ≤ 0.74) nanostructures crystallized from borate glasses

NASA Astrophysics Data System (ADS)

El Shabrawy, S.; Miglierini, M.; Schaaf, P.; Tzankov, D.; Georgieva, M.; Harizanova, R.; Rüssel, C.

2018-03-01

Glasses in the system 51.7 B2O3/9.3 K2O/1 P2O5/10.4 Fe2O3/(27.6 - y) MgO/y ZnO (with y = 0, 1, 2.5, 5, 7.5, 10, 13.8, and 20) were prepared by the conventional melt quenching method. The glass samples were thermally treated at 560 °C for 3 h in ambient conditions. Using 57Fe Mössbauer spectroscopy, the effect of the substitution of MgO by ZnO in the glass network and the effect on the precipitated crystallized phase was studied. The results showed that the ratio of Zn2+:Mg2+ in the precipitated crystals increases with the ZnO concentration in the glass. The isomer shift values indicated that iron occurs as Fe3+, which is distributed at the tetrahedral (A) and the octahedral [B] sites. Introducing ZnO leads to a relative increase of the Fe3+ concentration at the B sites at the expense of that occupying the A sites. This indicates the precipitation of ZnxMg1-x Fe2O4 nanoparticles, where Zn2+ ions favorably occupy the A sites. The average hyperfine field of the samples showed a strong dependence on the Zn concentration. At the highest Zn concentration of 13.8 and 20 mol%, the samples are paramagnetic, while for the smaller ones, the samples are superparamagnetic.

Transfer of useful variability of high grain iron and zinc from Aegilops kotschyi into wheat through seed irradiation approach.

PubMed

Verma, Shailender Kumar; Kumar, Satish; Sheikh, Imran; Malik, Sachin; Mathpal, Priyanka; Chugh, Vishal; Kumar, Sundip; Prasad, Ramasare; Dhaliwal, Harcharan Singh

2016-01-01

To transfer the 2S chromosomal fragment(s) of Aegilops kotschyi (2S(k)) into the bread wheat genome which could lead to the biofortification of wheat with high grain iron and zinc content. Wheat-Ae. kotschyi 2A/2S(k) substitution lines with high grain iron and zinc content were used to transfer the gene/loci for high grain Fe and Zn content into wheat using seed irradiation approach. Bread wheat plants derived from 40 krad-irradiated seeds showed the presence of univalents and multivalents during meiotic metaphase-I. Genomic in situ hybridization analysis of seed irradiation hybrid F2 seedlings showed several terminal and interstitial signals indicated the introgression of Ae. kotschyi chromosome segments. This proves the efficacy of seed radiation hybrid approach in gene transfer experiments. All the radiation-treated hybrid plants with high grain Fe and Zn content were analyzed with wheat group 2 chromosome-specific polymorphic simple sequence repeat markers to identify the introgression of small alien chromosome fragment(s). Radiation-induced hybrids showed more than 65% increase in grain iron and 54% increase in Zn contents with better harvest index than the elite wheat cultivar WL711 indicating effective and compensating translocations of 2S(k) fragments into wheat genome.

The behavior of iron and zinc stable isotopes accompanying the subduction of mafic oceanic crust: A case study from Western Alpine ophiolites

NASA Astrophysics Data System (ADS)

Inglis, Edward C.; Debret, Baptiste; Burton, Kevin W.; Millet, Marc-Alban; Pons, Marie-Laure; Dale, Christopher W.; Bouilhol, Pierre; Cooper, Matthew; Nowell, Geoff M.; McCoy-West, Alex J.; Williams, Helen M.

2017-07-01

Arc lavas display elevated Fe3+/ΣFe ratios relative to MORB. One mechanism to explain this is the mobilization and transfer of oxidized or oxidizing components from the subducting slab to the mantle wedge. Here we use iron and zinc isotopes, which are fractionated upon complexation by sulfide, chloride, and carbonate ligands, to remark on the chemistry and oxidation state of fluids released during prograde metamorphism of subducted oceanic crust. We present data for metagabbros and metabasalts from the Chenaillet massif, Queyras complex, and the Zermatt-Saas ophiolite (Western European Alps), which have been metamorphosed at typical subduction zone P-T conditions and preserve their prograde metamorphic history. There is no systematic, detectable fractionation of either Fe or Zn isotopes across metamorphic facies, rather the isotope composition of the eclogites overlaps with published data for MORB. The lack of resolvable Fe isotope fractionation with increasing prograde metamorphism likely reflects the mass balance of the system, and in this scenario Fe mobility is not traceable with Fe isotopes. Given that Zn isotopes are fractionated by S-bearing and C-bearing fluids, this suggests that relatively small amounts of Zn are mobilized from the mafic lithologies in within these types of dehydration fluids. Conversely, metagabbros from the Queyras that are in proximity to metasediments display a significant Fe isotope fractionation. The covariation of δ56Fe of these samples with selected fluid mobile elements suggests the infiltration of sediment derived fluids with an isotopically light signature during subduction.

The selective activation of a C-F bond with an auxiliary strong Lewis acid: a method to change the activation preference of C-F and C-H bonds.

PubMed

Wang, Lin; Sun, Hongjian; Li, Xiaoyan; Fuhr, Olaf; Fenske, Dieter

2016-11-15

The selective activation of the C-F bonds in substituted (2,6-difluorophenyl)phenylimines (2,6-F 2 H 3 C 6 -(C[double bond, length as m-dash]NH)-n'-R-C 6 H 4 (n' = 2, R = H (1); n' = 2, R = Me (2); n' = 4, R = tBu (3))) by Fe(PMe 3 ) 4 with an auxiliary strong Lewis acid (LiBr, LiI, or ZnCl 2 ) was explored. As a result, iron(ii) halides ((H 5 C 6 -(C[double bond, length as m-dash]NH)-2-FH 3 C 6 )FeX(PMe 3 ) 3 (X = Br (8); Cl (9)) and (n-RH 4 C 6 -(C[double bond, length as m-dash]NH)-2'-FH 3 C 6 )FeX(PMe 3 ) 3 (n = 2, R = Me, X = Br (11); n = 4, R = tBu, X = I (12))) were obtained. Under similar reaction conditions, using LiBF 4 instead of LiBr or ZnCl 2 , the reaction of (2,6-difluorophenyl)phenylimine with Fe(PMe 3 ) 4 afforded an ionic complex [(2,6-F 2 H 3 C 6 -(C[double bond, length as m-dash]NH)-H 4 C 6 )Fe(PMe 3 ) 4 ](BF 4 ) (10) via the activation of a C-H bond. The method of C-F bond activation with an auxiliary strong Lewis acid is appropriate for monofluoroarylmethanimines. Without the Lewis acid, iron(ii) hydrides ((2-RH 4 C 6 -(C[double bond, length as m-dash]NH)-2'-FH 3 C 6 )FeH(PMe 3 ) 3 (R = H (13); Me (14))) were generated from the reactions of Fe(PMe 3 ) 4 with the monofluoroarylmethanimines (2-FH 4 C 6 -(C[double bond, length as m-dash]NH)-2'-RC 6 H 4 (R = H (4); Me (5))); however, in the presence of ZnCl 2 or LiBr, iron(ii) halides ((2-RH 4 C 6 -(C[double bond, length as m-dash]NH)-H 4 C 6 )FeX(PMe 3 ) 3 (R = H, X = Cl (15); R = Me, X = Br (16))) could be obtained through the activation of a C-F bond. Furthermore, a C-F bond activation with good regioselectivity in (pentafluorophenyl)arylmethanimines (F 5 C 6 -(C[double bond, length as m-dash]NH)-2,6-Y 2 C 6 H 3 (Y = F (6); H (7))) could be realized in the presence of ZnCl 2 to produce iron(ii) chlorides ((2,6-Y 2 H 3 C 6 -(C[double bond, length as m-dash]NH)-F 4 C 6 )FeCl(PMe 3 ) 3 (Y = F (17); H (18))). This series of iron(ii) halides could be used to catalyze the hydrosilylation reaction of aldehydes. Due to the stability of iron(ii) halides to high temperature, the reaction mixture was allowed to be heated to 100 °C and the reaction could finish within 0.5 h.

Evaluation of elemental enrichments in surface sediments off southwestern Taiwan

NASA Astrophysics Data System (ADS)

Chen, Chen-Tung; Kandasamy, Selvaraj

2008-05-01

Surface slices of 20 sediment cores, off southwestern Taiwan, and bed sediment of River Kaoping were measured for major and trace elements (Al, As, Ca, Cd, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Ti, V, and Zn) to evaluate the geochemical processes responsible for their distribution, including elemental contamination. Major element/Al ratio and mean grain size indicate quartz-dominated, coarse grained sediments that likely derived from sedimentary rocks of Taiwan and upper crust of Yangtze Craton. Bi-plot of SiO2 versus Fe2O{3/T} suggests the possible iron enrichment in sediments of slag dumping sites. Highest concentrations of Cr, Mn, P, S, and Zn found in sediments of dumping sites support this. Correlation analysis shows dual associations, detrital and organic carbon, for Cr, P, S, and V with the latter association typical for sediments in dumping sites. Normalization of trace elements to Al indicates high enrichment factors (>2) for As, Cd, Pb, and Zn, revealing contamination. Factor analysis extracted four geochemical associations with the principal factor accounted for 25.1% of the total variance and identifies the combined effects of dumped iron and steel slag-induced C-S-Fe relationship owing to authigenic precipitation of Fe-Mn oxyhydroxides and/or metal sulfides, and organic matter complexation of Fe, Mn, Ca, Cr, P, and V. Factors 2, 3, and 4 reveal detrital association (Ti, Al, Ni, Pb, Cu, and V), effect of sea salt (Cl, Mg, Na, and K) and anthropogenic component (As and Zn)-carbonate link, respectively, in the investigated sediments.

Discrimination of Venezuelan spirituous beverages by a trace element-radial basis neural network approach.

PubMed

Hernández-Caraballo, Edwin A; Avila de Hernández, Rita M; Rivas-Echeverría, Francklin; Capote-Luna, Tarcisio

2008-01-15

Radial basis neural networks (RBNNs) were developed and evaluated for discrimination of specimens of 'aguardiente de Cocuy', a spirituous beverage produced in the northwestern region of Venezuela. The beverage is distilled from the must of Agave cocui Trelease in an artisanship fashion with little quality control. Forty specimens, with known concentrations of copper, iron, and zinc, were used in this study. The specimens were previously collected in various locations around Sucre Municipality (Falcón State) and Urdaneta Municipality (Lara State). The normalized concentrations of these elements served as indirect descriptors of origin (input data). They were presented to the neural networks through 1-3 input nodes in seven different combinations. In addition, two categories (two collection sites) and four categories (two collection sites+two manufacturing conditions) were designated as output data, in order to assess the impact of such selection on the discrimination performance. The overall performance of the four-category RBNNs was as follows (the input data is indicated in parentheses): (Cu-Fe)>(Cu-Zn)>(Cu)>(Zn)>(Fe-Zn)>(Cu-Fe-Zn)>(Fe). In this case, the highest percentage of correct hits was 82.5%. For the two-category RBNNs, the performance decreased as indicated below: (Cu)>(Cu-Fe)>(Cu-Zn)>(Fe-Zn)>(Zn) approximately (Cu-Fe-Zn)>(Fe). The reduction in the number of categories led to an increase in the discrimination performance of all the RBNNs, the best of which was 90.0%. The possibility of discriminating specimens of 'aguardiente de Cocuy' with such an accuracy, based on a single-element determination, is particularly attractive as it would result in a reduction of analysis' costs and laboratory's response time.

Growth of hybrid carbon nanostructures on iron-decorated ZnO nanorods

NASA Astrophysics Data System (ADS)

Mbuyisa, Puleng N.; Rigoni, Federica; Sangaletti, Luigi; Ponzoni, Stefano; Pagliara, Stefania; Goldoni, Andrea; Ndwandwe, Muzi; Cepek, Cinzia

2016-04-01

A novel carbon-based nanostructured material, which includes carbon nanotubes (CNTs), porous carbon, nanostructured ZnO and Fe nanoparticles, has been synthetized using catalytic chemical vapour deposition (CVD) of acetylene on vertically aligned ZnO nanorods (NRs). The deposition of Fe before the CVD process induces the presence of dense CNTs in addition to the variety of nanostructures already observed on the process done on the bare NRs, which range from amorphous graphitic carbon up to nanostructured dendritic carbon films, where the NRs are partially or completely etched. The combination of scanning electron microscopy and in situ photoemission spectroscopy indicate that Fe enhances the ZnO etching, and that the CNT synthesis is favoured by the reduced Fe mobility due to the strong interaction between Fe and the NRs, and to the presence of many defects, formed during the CVD process. Our results demonstrate that the resulting new hybrid shows a higher sensitivity to ammonia gas at ambient conditions (∼60 ppb) than the carbon nanostructures obtained without the aid of Fe, the bare ZnO NRs, or other one-dimensional carbon nanostructures, making this system of potential interest for environmental ammonia monitoring. Finally, in view of the possible application in nanoscale optoelectronics, the photoexcited carrier behaviour in these hybrid systems has been characterized by time-resolved reflectivity measurements.

Green synthesis of novel zinc iron oxide (ZnFe2O4) nanocomposite via Moringa Oleifera natural extract for electrochemical applications

NASA Astrophysics Data System (ADS)

Matinise, N.; Kaviyarasu, K.; Mongwaketsi, N.; Khamlich, S.; Kotsedi, L.; Mayedwa, N.; Maaza, M.

2018-07-01

The main motivation of the research study involves development of reliable, accurate, inexpensive and environmental friendly method for the synthesis of zinc ferrite (ZnFe2O4) nanocomposites. It was thought of interest to synthesized zinc ferrite via green synthetic method using Moringa Oleifera extract. For the first time, we used green synthetic route via Moringa Oleifera extract acted as both chelating and reducing agents to synthesis spinel ZnFe2O4 nanocomposites. The physical and electrochemical properties were characterized using different techniques such as High Resolve Transmission Electron Microscope (HRTEM) Energy Dispersive X-ray Spectroscopy (EDS) X-ray diffraction (XRD) Fourier transform-infrared (FT-IR) Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The XRD pattern thus clearly illustrated that the ZnFe2O4 nanocmposites synthesized by the green method were good crystalline in nature. The time constant and exchange current of ZnFe2O4 nanocomposites from EIS analysis were calculated and found to be 5.2001 × 10-4 s/rad and 6.59432 × 10-4 A, respectively. Based on the electrochemical results, GCE/ZnFe2O4 electrode exhibited a good voltametric response, high electro-activity, and excellent electrochemical performance making it a highly suitable/promising electrode for electrochemical applications.

High purity Fe3O4 from Local Iron Sand Extraction

NASA Astrophysics Data System (ADS)

Gunanto, Y. E.; Izaak, M. P.; Jobiliong, E.; Cahyadi, L.; Adi, W. A.

2018-04-01

Indonesia has a long coastline and is rich with iron sand. The iron sand is generally rich in various elements such as iron and titanium. One of the products processing of the iron sand mineral is iron (II) (III) oxide (magnetite Fe3O4). The stages of purification process to extracting magnetite phase and discarding the other phases has been performed. Magnetite phase analysis of ironsand extraction retrieved from Indonesia have been investigated. The result of analysis element of iron sand shows that it consists of majority Fe around 65 wt%. However, there are still 17 impurities such as Ti, Al, Ce, Co, Cr, Eu, La, Mg, Mn, Na, Sc, Sm, Th, V, Yb, and Zn. After extraction process, Fe element content increases up to 94%. The iron sand powder after milling for 10 hours and separating using a magnetic separator, the iron sand powders are dissolved in acid chloride solution to form a solution of iron chloride, and this solution is sprinkled with sodium hydroxide to obtain fine powders of Fe3O4. The fine powders which formed were washed with de-mineralization water. The X-ray diffraction pattern shows that the fine powders have a single phase of Fe3O4. The analysis result shows that the sample has the chemical formula: Fe3O4 with a cubic crystal system, space group: Fd-3m and lattice parameters: a = b = c = 8.3681 (1) Å, α = β = γ = 90°. The microstructure analysis shows that the particle of Fe3O4 homogeneously shaped like spherical. The magnetic properties using vibrating sample magnetometer shows that Fe3O4 obtained have ferromagnetic behavior with soft magnetic characteristics. We concluded that this purification of iron sand had been successfully performed to obtain fine powders of Fe3O4 with high purity.

Electroplating wastewater treatment by the combined electrochemical and ozonation methods.

PubMed

Orescanin, Visnja; Kollar, Robert; Mikelic, Ivanka Lovrencic; Nad, Karlo

2013-01-01

This article presents a pilot-plant study of the electroplating wastewater treatment by the processes of electroreduction with iron electrode plates, and electrocoagulation/ozonation with aluminum electrode set, followed by the process of ozonation. The initial effluent was found to be highly enriched in heavy metals and to possess the elevated levels of organic contaminants. The values of Cr(VI), Fe, Ni, Cu, Zn, Pb, TOC, and COD exceeded the upper permissible limits of 63, 220.2, 1.1, 7, 131.3, 1.7, 12.3, and 11.4 times, respectively. The heavy metal removal was forced either by the coagulation/flocculation using Fe(II), Fe(III), and Al(III) ions released into the treated solution by the electrochemical corrosion of the sacrificial iron and aluminum electrodes, or the precipitation of the metal hydroxides as well as co-precipitation with iron and aluminum hydroxides. The principle organic matter destruction mechanisms were ozone oxidation and the indirect oxidation with chlorine/hypochlorite formed by the anodic oxidation of chloride already present in the wastewater. Following the combined treatment, the removal efficiencies of Cr(VI), Fe, Ni, Cu, Zn, Pb, TOC, and COD were 99.94%, 100.00%, 95.86%, 98.66%, 99.97%, 96.81%, 93.24%, and 93.43%, respectively, thus complying with the regulated values.

Excess dietary cobalt in pigs

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

Huck, D.W.; Clawson, A.J.

1976-01-01

Five experiments were conducted, in which 240 growing finishing pigs were used, to determine the level of Cobalt (Co) which is toxic. Pigs tolerated up to 200 mg/kg of Co when added to corn-soybean meal diets containing 82 to 178 mg/kg of iron. The addition of 400 or 600 mg/kg of Co caused anorexia, growth depression, stiff-leggedness, humped back, incoordination and extreme muscular tremors. Serum and organ levels of Co were greatly increased and serum and organ levels of iron (Fe) were significantly reduced by added dietary cobalt. The addition of .5 or 1.0% methionine to the diet completely alleviatedmore » the toxic affects caused by the 600 mg level of Co and restored serum Fe to near normal levels. The addition of Fe, manganese (Mn) and zinc (Zn) in combination at levels of 200, 400 and 400 mg/kg, respectively, also alleviated the growth depression caused by the 400 mg level of Co and higher levels of Fe, Mn and Zn (200, 600 and 600 mg/kg) partially restored feed intake and growth when 600 mg of Co was fed. Iron alone was not effective in overcoming the growth depression caused by 400 or 600 mg/kg of dietary cobalt. 31 references, 1 figure, 11 tables.« less

Synergistic effect of biogenic Fe3+ coupled to S° oxidation on simultaneous bioleaching of Cu, Co, Zn and As from hazardous Pyrite Ash Waste.

PubMed

Panda, Sandeep; Akcil, Ata; Mishra, Srabani; Erust, Ceren

2017-03-05

Pyrite ash, a waste by-product formed during roasting of pyrite ores, is a good source of valuable metals. The waste is associated with several environmental issues due to its dumping in sea and/or land filling. Although several other management practices are available for its utilization, the waste still awaits and calls for an eco-friendly biotechnological application for metal recovery. In the present study, chemolithotrophic meso-acidophilic iron and sulphur oxidisers were evaluated for the first time towards simultaneous mutli-metal recovery from pyrite ash. XRD and XRF analysis indicated higher amount of Hematite (Fe 2 O 3 ) in the sample. ICP-OES analysis indicated concentrations of Cu>Zn>Co>As that were considered for bioleaching. Optimization studies indicated Cu - 95%, Co - 97%, Zn - 78% and As - 60% recovery within 8days at 10% pulp density, pH - 1.75, 10% (v/v) inoculum and 9g/L Fe 2+ . The productivity of the bioleaching system was found to be Cu - 1696ppm/d (12% dissolution/d), Co - 338ppm/d (12.2% dissolution/d), Zn k 576ppm/d (9.8% dissolution/d) and As - 75ppm/d (7.5% dissolution/d). Synergistic actions for Fe 2+ - S° oxidation by iron and sulphur oxidisers were identified as the key drivers for enhanced metal dissolution from pyrite ash sample. Copyright © 2016 Elsevier B.V. All rights reserved.

Induced Phytoextraction of Lead Through Chemical Manipulation of Switchgrass and Corn; Role of Iron Supplement.

PubMed

Johnson, Deayne M; Deocampo, Daniel M; El-Mayas, Hanan; Greipsson, Sigurdur

2015-01-01

The effects of combined chemical application of benomyl, ethylenedianinetetraacetate (EDTA), and iron (Fe) (foliar and root) on lead (Pb) phytoextraction by switchgrass (Panicum virgatum) and corn (Zea mays) was examined. Switchgrass was grown in Pb-contaminated urban topsoil with the following treatments: (C) Control, (B) benomyl, (E) EDTA, (F) foliar-Fe, (BE) benomyl + EDTA, (BF) benomyl + foliar-Fe, (FE) foliar-Fe + EDTA, (BFE) benomyl + foliar-Fe + EDTA. Corn was grown in sand-culture supplemented with Pb (500 mg kg(-1)) with the following treatments: (C) control, (B) benomyl, (E) EDTA, (F) root-Fe, (BE) benomyl + EDTA, (BF) benomyl + root-Fe, (FE) root-iron + EDTA, and, (BFE) benomyl + root-Fe + EDTA. All treatments were replicated three times and pots were arranged in a completely randomized design. Plants were analyzed for element concentration (Fe, Zn, P, and Pb) using either inductively coupled plasma (argon) atomic emission spectroscopy (ICP-AES) or graphite furnace atomic absorption spectrometer. Iron supplementation (foliar and root) affected Pb-translocation in plants. Foliar-Fe treatment increased translocation ratio of Pb (TF-Pb) significantly compared to other treatments with the exception of plants treated with benomyl and BF. Root-Fe treatment in combination with EDTA (FE) increased TF-Pb significantly compared to other treatments. Phytoextraction was improved by the combined chemical application; plants treated with BFE treatment increased Pb-total-phytoextraction by 424% compared to Control plants.

Metal specificity of an iron-responsive element in Alzheimer's APP mRNA 5'untranslated region, tolerance of SH-SY5Y and H4 neural cells to desferrioxamine, clioquinol, VK-28, and a piperazine chelator.

PubMed

Bandyopadhyay, S; Huang, X; Cho, H; Greig, N H; Youdim, M B; Rogers, J T

2006-01-01

Iron closely regulates the expression of the Alzheimer's Amyloid Precursor Protein (APP) gene at the level of message translation by a pathway similar to iron control of the translation of the ferritin L- and H mRNAs by Iron-responsive Elements in their 5' untranslated regions (5'UTRs). Using transfection based assays in SH-SY5Y neuroblastoma cells we tested the relative efficiency by which iron, copper and zinc up-regulate IRE activity in the APP 5'UTR. Desferrioxamine (high affinity Fe3+ chelator), (ii) clioquinol (low affinity Fe/Cu/Zn chelator), (iii) piperazine-1 (oral Fe chelator), (iv) VK-28 (oral Fe chelator), were tested for their relative modulation of APP 5' UTR directed translation of a luciferase reporter gene. Iron chelation based therapeutic strategies for slowing the progression of Alzheimer's disease (and other neurological disorders that manifest iron imbalance) are discussed with regard to the relative neural toxic action of each chelator in SH-SY5Y cells and in H4 glioblastoma cells.

Meta-QTL analysis of seed iron and zinc concentration in common bean (Phaseolus vulgaris L.)

USDA-ARS?s Scientific Manuscript database

Common bean (Phaseolus vulgaris L.) is the most important legume for human consumption worldwide and it is an important source of microelements, especially iron and zinc. Bean biofortification programs develop new varieties with high levels of Fe and Zn targeted for countries with human micronutrien...

Preparation of Superparamagnetic Zn0.5Mn0.5Fe2O4 Particle by Coprecipitation-Sonochemical Method for Radar Absorbing Material

NASA Astrophysics Data System (ADS)

Taufiq, A.; Bahtiar, S.; Sunaryono; Hidayat, N.; Hidayat, A.; Mufti, N.; Diantoro, M.; Fuad, A.; Munasir; Rahmawati, R.; Adi, W. A.; Pratapa, S.; Darminto

2017-05-01

One of many applications of spinel ferrite nanoparticles is related to their performance as radar absorbing materials. In this work, we report developing synthesis method through combined coprecipitation-sonochemical routes in preparing Zn0.5Mn0.5Fe2O4 nanoparticle from iron sand in Indonesia as a vital raw material. The structure, size, morphology, and elements of the Zn0.5Mn0.5Fe2O4 nanoparticle were investigated via X-Ray diffractometry and Transmission/Scanning Electron Microscopy (TEM/SEM) combining Energy Dispersive Spectroscopy (EDS). The magnetic properties of the Zn0.5Mn0.5Fe2O4 nanoparticle were characterized by using Vibrating Sample Magnetometer (VSM). Furthermore, the reflection loss character of the Zn0.5Mn0.5Fe2O4 nanoparticle was determined via Vector Network Analyzer (VNA). From the qualitative and quantitative analysis of the XRD data, it can be identified that the Zn0.5Mn0.5Fe2O4 particle formed a spinel cubic structure in a single phase with the lattice parameter of approximately 8.401 Å. It is known from the TEM image that the Zn0.5Mn0.5Fe2O4 particle had a size of about 9.7 nm and tended to agglomerate. Furthermore, the data analysis of the M(H) curve presented that the Zn0.5Mn0.5Fe2O4 nanoparticle has a superparamagnetic behavior with the saturation magnetization of approximately 43 emu/g. Finally, the data analysis of the reflection loss as a function of frequency showed that the Zn0.5Mn0.5Fe2O4 nanoparticle performs as a radar absorbing material with the absorption performance of approximately -11.0 dB at the frequency of 10.8 GHz

Reaction intermediates in the catalytic Gif-type oxidation from nuclear inelastic scattering

NASA Astrophysics Data System (ADS)

Rajagopalan, S.; Asthalter, T.; Rabe, V.; Laschat, S.

2016-12-01

Nuclear inelastic scattering (NIS) of synchrotron radiation, also known as nuclear resonant vibrational spectroscopy (NRVS), has been shown to provide valuable insights into metal-centered vibrations at Mössbauer-active nuclei. We present a study of the iron-centered vibrational density of states (VDOS) during the first step of the Gif-type oxidation of cyclohexene with a novel trinuclear Fe3(μ 3-O) complex as catalyst precursor. The experiments were carried out on shock-frozen solutions for different combinations of reactants: Fe3(μ 3-O) in pyridine solution, Fe3(μ 3-O) plus Zn/acetic acid in pyridine without and with addition of either oxygen or cyclohexene, and Fe3(μ 3-O)/Zn/acetic acid/pyridine/cyclohexene (reaction mixture) for reaction times of 1 min, 5 min, and 30 min. The projected VDOS of the Fe atoms was calculated on the basis of pseudopotential density functional calculations. Two possible reaction intermediates were identified as [Fe(III)(C5H5N)2(O2CCH3)2]+ and Fe(II)(C5H5N)4(O2CCH3)2, yielding evidence that NIS (NRVS) allows to identify the presence of iron-centered intermediates also in complex reaction mixtures.

Correlations in distribution and concentration of calcium, copper and iron with zinc in isolated extracellular deposits associated with age-related macular degeneration

USGS Publications Warehouse

Flinn, Jane M; Kakalec, Peter; Tappero, Ryan; Jones, Blair F.; Lengyel, Imre

2014-01-01

Zinc (Zn) is abundantly enriched in sub-retinal pigment epithelial (RPE) deposits, the hallmarks of age-related macular degeneration (AMD), and is thought to play a role in the formation of these deposits. However, it is not known whether Zn is the only metal relevant for sub-RPE deposit formation. Because of their involvement in the pathogenesis of AMD, we determined the concentration and distribution of calcium (Ca), iron (Fe) and copper (Cu) and compared these with Zn in isolated and sectioned macular (MSD), equatorial (PHD) and far peripheral (FPD) sub-RPE deposits from an 86 year old donor eye with post mortem diagnosis of early AMD. The sections were mounted on Zn free microscopy slides and analyzed by microprobe synchrotron X-ray fluorescence (μSXRF). Metal concentrations were determined using spiked sectioned sheep brain matrix standards, prepared the same way as the samples. The heterogeneity of metal distributions was examined using pixel by pixel comparison. The orders of metal concentrations were Ca ⋙ Zn > Fe in all three types of deposits but Cu levels were not distinguishable from background values. Zinc and Ca were consistently present in all deposits but reached highest concentration in MSD. Iron was present in some but not all deposits and was especially enriched in FPD. Correlation analysis indicated considerable variation in metal distribution within and between sub-RPE deposits. The results suggest that Zn and Ca are the most likely contributors to deposit formation especially in MSD, the characteristic risk factor for the development of AMD in the human eye.

Separation of copper, iron, and zinc from complex aqueous solutions for isotopic measurement

USGS Publications Warehouse

Borrok, D.M.; Wanty, R.B.; Ridley, W.I.; Wolf, R.; Lamothe, P.J.; Adams, M.

2007-01-01

The measurement of Cu, Fe, and Zn isotopes in natural samples may provide valuable information about biogeochemical processes in the environment. However, the widespread application of stable Cu, Fe, and Zn isotope chemistry to natural water systems remains limited by our ability to efficiently separate these trace elements from the greater concentrations of matrix elements. In this study, we present a new method for the isolation of Cu, Fe, and Zn from complex aqueous solutions using a single anion-exchange column with hydrochloric acid media. Using this method we are able to quantitatively separate Cu, Fe, and Zn from each other and from matrix elements in a single column elution. Elution of the elements of interest, as well as all other elements, through the anion-exchange column is a function of the speciation of each element in the various concentrations of HCl. We highlight the column chemistry by comparing our observations with published studies that have investigated the speciation of Cu, Fe, and Zn in chloride solutions. The functionality of the column procedure was tested by measuring Cu, Fe, and Zn isotopes in a variety of stream water samples impacted by acid mine drainage. The accuracy and precision of Zn isotopic measurements was tested by doping Zn-free stream water with the Zn isotopic standard. The reproducibility of the entire column separation process and the overall precision of the isotopic measurements were also evaluated. The isotopic results demonstrate that the Cu, Fe, and Zn column separates from the tested stream waters are of sufficient purity to be analyzed directly using a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS), and that the measurements are fully-reproducible, accurate, and precise. Although limited in scope, these isotopic measurements reveal significant variations in ??65Cu (- 1.41 to + 0.30???), ??56Fe (- 0.56 to + 0.34???), and ??66Zn (0.31 to 0.49???) among samples collected from different abandoned mines within a single watershed. Hence, Cu, Fe, and Zn isotopic measurements may be a powerful tool for fingerprinting specific metal sources and/or examining biogeochemical reactions within fresh water systems.

The Impact of Iron Adsorption on the Electronic and Photocatalytic Properties of the Zinc Oxide (0001) Surface: A First-Principles Study.

PubMed

Cheng, Jingsi; Wang, Ping; Hua, Chao; Yang, Yintang; Zhang, Zhiyong

2018-03-12

The structural stability, electronic structure, and optical properties of an iron-adsorbed ZnO (0001) surface with three high-symmetry adsorption sites are investigated with first-principle calculations on the basis of density functional theory and the Hubbard-U method. It is found that the iron adatom in the H₃ adsorption site of ZnO (0001) surface has the lowest adsorption energy of -5.665 eV compared with T₄ and Top sites. For the Top site, compared with the pristine ZnO (0001) surface, the absorption peak located at 1.17 eV has a red shift, and the elevation of the absorption coefficient is more pronounced in the visible-light region, because the Fe-related levels are introduced in the forbidden band and near the Fermi level. The electrostatic potential computation reveals that the work function of the ZnO (0001) surface is significantly decreased from 2.340 to 1.768 eV when iron is adsorbed on the Top site. Furthermore, the degradation mechanism based on the band structure is analyzed. It can be concluded that the adsorption of iron will promote the separation of photoinduced carriers, thus improving the photocatalytic activity of ZnO (0001) surface. Our study benefits research on the photocatalytic activity of ZnO and the utilization rate of solar energy.

Zinc abundances in Galactic bulge field red giants: Implications for damped Lyman-α systems

NASA Astrophysics Data System (ADS)

Barbuy, B.; Friaça, A. C. S.; da Silveira, C. R.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.

2015-08-01

Context. Zinc in stars is an important reference element because it is a proxy to Fe in studies of damped Lyman-α systems (DLAs), permitting a comparison of chemical evolution histories of bulge stellar populations and DLAs. In terms of nucleosynthesis, it behaves as an alpha element because it is enhanced in metal-poor stars. Abundance studies in different stellar populations can give hints to the Zn production in different sites. Aims: The aim of this work is to derive the iron-peak element Zn abundances in 56 bulge giants from high resolution spectra. These results are compared with data from other bulge samples, as well as from disk and halo stars, and damped Lyman-α systems, in order to better understand the chemical evolution in these environments. Methods: High-resolution spectra were obtained using FLAMES+UVES on the Very Large Telescope. We computed the Zn abundances using the Zn i lines at 4810.53 and 6362.34 Å. We considered the strong depression in the continuum of the Zn i 6362.34 Å line, which is caused by the wings of the Ca i 6361.79 Å line suffering from autoionization. CN lines blending the Zn i 6362.34 Å line are also included in the calculations. Results: We find [Zn/Fe] = +0.24 ± 0.02 in the range -1.3 < [Fe/H] < -0.5 and [Zn/Fe] = + 0.06 ± 0.02 in the range -0.5 < [Fe/H] < -0.1, whereas for [Fe/H] ≥ -0.1, it shows a spread of -0.60 < [Zn/Fe] < + 0.15, with most of these stars having low [Zn/Fe] < 0.0. These low zinc abundances at the high metallicity end of the bulge define a decreasing trend in [Zn/Fe] with increasing metallicities. A comparison with Zn abundances in DLA systems is presented, where a dust-depletion correction was applied for both Zn and Fe. When we take these corrections into account, the [Zn/Fe] vs. [Fe/H] of the DLAs fall in the same region as the thick disk and bulge stars. Finally, we present a chemical evolution model of Zn enrichment in massive spheroids, representing a typical classical bulge evolution. Observations collected both at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Table 6 is available in electronic form at http://www.aanda.org

The interaction of phytosiderophores with soil as a function of time

NASA Astrophysics Data System (ADS)

Schenkeveld, W. D. C.; Oburger, E.; Schindlegger, Y.; Regelsberger, A.; Hann, S.; Puschenreiter, M.; Kraemer, S. M.

2012-04-01

Graminaceous plant species (grasses) exude natural chelating agents, called phytosiderophores (PS) for the purpose of iron acquisition, in particular under conditions of iron deficiency stress. The biogeochemistry of phytosiderophores in the rhizosphere is still poorly understood. Processes like mobilization of iron or other metals by PS, and the degradation of the chelating agent were previously studied under conditions quite remote from those observed in the rhizosphere, e.g. in hydroponics systems or in soil suspensions with low soils to solution ratios. Such experimental conditions may lead to artifacts like for instance the depletion of available metal fractions. The aim of the present study is to contribute to a more accurate quantification of the source and sink terms determining PS concentrations in the rhizosphere. The mobilization of iron and other metals from two clay soils and two sandy soils by the PS deoxymugineic acid (DMA) was studied as a function of time in a batch experiment with a soil-solution ratio of 1. Both soils causing iron deficiency stress in plants and a reference soil not doing so were included. To examine the effect of ligand biodegradation on metal mobilization, treatments with and without sterilant (azide) were included. The fraction of added DMA mobilizing Fe ranged from 10 to 60% and correlates positively with Fe availability (DTPA-extractable Fe) and negatively with the clay content of the soils. In particular in soils of low Fe availability, Fe mobilization by DMA was severely compromised by mobilization of other metals including Cu, Zn, Ni and Co. The relative importance of Zn as competing cation decreases over time, while the importance of Cu increases. In the treatment without sterilant addition, metal-DMA complexes were removed from solution after 4 days in all soils; in the clay soils, Fe-DMA complexes were already removed before. The highest concentration of mobilized Fe did not depend on whether sterilant was added or not, except in one soil; this concentration was reached after 0.25 up to 8 hours. Also in treatments with sterilant addition, the FeDMA concentration eventually declined, but removal from solution was not complete when the experiment ended after one week. This indicates that besides biodegradation there are other processes significantly compromising the FeDMA concentration in the soil. In summary, these results emphasize the importance of the kinetics and thermodynamics of coupled rhizosphere processes for plant iron acquisition.

Effect of nanoscale zero-valent iron and magnetite (Fe3O4) on the fate of metals during anaerobic digestion of sludge.

PubMed

Suanon, Fidèle; Sun, Qian; Mama, Daouda; Li, Jiangwei; Dimon, Biaou; Yu, Chang-Ping

2016-01-01

Anaerobic digestion (AD) is one of the most widely used processes to stabilize waste sewage sludge and produce biogas renewable energy. In this study, two different iron nanoparticles [nanoscale zero-valent iron (nZVI) and magnetite (Fe3O4)] were used in the mesophilic AD processes (37 ± 1 °C) to improve biogas production. In addition, changes of heavy metal (Cd, Co, Cu, Zn, Ni and Cr) speciation during AD of sludge with and without iron nanoparticles have been investigated. Concentrations of metals in the initial sludge were as follows: 63.1, 73.4, 1102.2, 2060.3, 483.9 and 604.1 mg kg(-1) (dry sludge basis) for Cd, Co, Cu, Zn, Ni and Cr, respectively. Sequential fractionation showed that metals were predominantly bonded to organic matter and carbonates in the initial sludge. Compared with AD without iron nanoparticles, the application of iron nanoparticles (at dose of 0.5% in this study) showed positive impact not only on biogas production, but also on improvement of metals stabilization in the digestate. Metals were found concentrated in Fe-Mn bound and residual fractions and little was accumulated in the liquid digestate and most mobile fractions of solid digestate (water soluble, exchangeable and carbonates bound). Therefore, iron nanoparticles when properly used, could improve not only biogas yield, but also regulate and control the mobilization of metals during AD process. However, our study also observed that iron nanoparticles could promote the immobilization of phosphorus within the sludge during AD, and more research is needed to fully address the mechanism behind this phenomenon and the impact on future phosphorus reuse. Copyright © 2015 Elsevier Ltd. All rights reserved.

Moessbauer studies in Zn(2+)0.3 Mn(2+)0.7 Mn(3+) (2-y) Fe(3+) (2-y) O4

NASA Technical Reports Server (NTRS)

Gupta, R. G.; Mendiratta, R. G.; Escue, W. T.

1975-01-01

The Mossbauer effect has proven to be effective in the study of nuclear hyperfine interactions. Ferrite systems having the formula (Zn(2+)0.3)(Mn(2+)0.7)(Mn(3+)y)(Fe(3+)2-y)(O4) were prepared and studied. These systems can be interpreted as mangacese-doped zinc and a part of iron ions. A systematic study of these systems is presented to promote an understanding of their microstructure for which various theories were proposed.

Thermosynechococcus elongatus DpsA binds Zn(II) at a unique three histidine-containing ferroxidase center and utilizes O2 as iron oxidant with very high efficiency, unlike the typical Dps proteins.

PubMed

Alaleona, Flaminia; Franceschini, Stefano; Ceci, Pierpaolo; Ilari, Andrea; Chiancone, Emilia

2010-02-01

The cyanobacterium Thermosynechococcus elongatus is one the few bacteria to possess two Dps proteins, DpsA-Te and Dps-Te. The present characterization of DpsA-Te reveals unusual structural and functional features that differentiate it from Dps-Te and the other known Dps proteins. Notably, two Zn(II) are bound at the ferroxidase center, owing to the unique substitution of a metal ligand at the A-site (His78 in place of the canonical aspartate) and to the presence of a histidine (His164) in place of a hydrophobic residue at a metal-coordinating distance in the B-site. Only the latter Zn(II) is displaced by incoming iron, such that Zn(II)-Fe(III) complexes are formed upon oxidation, as indicated by absorbance and atomic emission spectroscopy data. In contrast to the typical behavior of Dps proteins, where Fe(II) oxidation by H(2)O(2) is about 100-fold faster than by O(2), in DpsA-Te the ferroxidation efficiency of O(2) is very high and resembles that of H(2)O(2). Oxygraphic experiments show that two Fe(II) are required to reduce O(2), and that H(2)O(2) is not released into solution at the end of the reaction. On this basis, a reaction mechanism is proposed that also takes into account the formation of Zn(II)-Fe(III) complexes. The physiological significance of the DpsA-Te behavior is discussed in the framework of a possible localization of the protein at the thylakoid membranes, where photosynthesis takes place, with the consequent increased formation of reactive oxygen species.

Nanosized zero-valent iron as Fenton-like reagent for ultrasonic-assisted leaching of zinc from blast furnace sludge.

PubMed

Mikhailov, Ivan; Komarov, Sergey; Levina, Vera; Gusev, Alexander; Issi, Jean-Paul; Kuznetsov, Denis

2017-01-05

Ultrasonic-assisted sulphuric acid leaching combined with a Fenton-like process, utilizing nanoscale zero-valent iron (nZVI), was investigated to enhance the leaching of zinc from the blast furnace sludge (BFS). The leaching of iron (Fe) and zinc (Zn) from the sludge was investigated using Milli-Q water/BFS ratio of 10 and varying the concentration of hydrogen peroxide, sulphuric acid, the temperature, the input energy for ultrasound irradiation, and the presence or absence of nZVI as a Fenton reagent. The results showed that with 1g/l addition of nZVI and 0.05M of hydrogen peroxide, the kinetic rate of Zn leaching increased with a maximum dissolution degree of 80.2%, after 5min treatment. In the absence of nZVI, the maximum dissolution degree of Zn was 99.2%, after 15min treatment with 0.1M of hydrogen peroxide. The rate of Zn leaching at several concentrations of hydrogen peroxide is accelerated in the presence of nZVI although a reduction in efficiency was observed. The loss of Fe was no more than 3%. On the basis of these results, the possible route for BFS recycling has been proposed (BFS slurry mixed with sulphuric acid and hydrogen peroxide is recirculated under ultrasonic irradiation then separated). Copyright © 2016 Elsevier B.V. All rights reserved.

Toxicity of Superparamagnetic Iron Oxide Nanoparticles on Green Alga Chlorella vulgaris

PubMed Central

Barhoumi, Lotfi

2013-01-01

Toxicity of superparamagnetic iron oxide nanoparticles (SPION) was investigated on Chlorella vulgaris cells exposed during 72 hours to Fe3O4 (SPION-1), Co0.2Zn0.8Fe2O4 (SPION-2), or Co0.5Zn0.5Fe2O4 (SPION-3) to a range of concentrations from 12.5 to 400 μg mL−1. Under these treatments, toxicity impact was indicated by the deterioration of photochemical activities of photosynthesis, the induction of oxidative stress, and the inhibition of cell division rate. In comparison to SPION-2 and -3, exposure to SPION-1 caused the highest toxic effects on cellular division due to a stronger production of reactive oxygen species and deterioration of photochemical activity of Photosystem II. This study showed the potential source of toxicity for three SPION suspensions, having different chemical compositions, estimated by the change of different biomarkers. In this toxicological investigation, algal model C. vulgaris demonstrated to be a valuable bioindicator of SPION toxicity. PMID:24369015

An alternative approach to recovering valuable metals from zinc phosphating sludge.

PubMed

Kuo, Yi-Ming

2012-01-30

This study used a vitrification process (with good potential for commercialization) to recover valuable metals from Zn phosphating sludge. The involved vitrification process achieves two major goals: it transformed hazardous Zn phosphating sludge into inert slag and it concentrated Fe (83.5%) and Zn (92.8%) into ingot and fine particulate-phase material, respectively. The Fe content in the ingot was 278,000 mg/kg, making the ingot a potential raw material for iron making. The fine particulate-phase material (collected from flue gas) contained abundant Zn (544,000 mg/kg) in the form of ZnO. The content (67.7%) of ZnO was high, so it can be directly sold to refineries. The recovered coarse particulate-phase material, with insufficient amount of ZnO, can be recycled as a feeding material for Zn re-concentration. Therefore, the vitrification process can not only treat hazardous materials but also effectively recover valuable metals. Copyright © 2011 Elsevier B.V. All rights reserved.

Highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste with amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent.

PubMed

Bao, Shuangyou; Tang, Lihong; Li, Kai; Ning, Ping; Peng, Jinhui; Guo, Huibin; Zhu, Tingting; Liu, Ye

2016-01-15

Amino-functionalized Fe3O4@SiO2 magnetic nano-adsorbent was used as a novel sorbent to highly selective removal of Zn(II) ion from hot-dip galvanizing pickling waste in the presence of Fe(II). These hot-dip galvanizing pickling waste mainly contain ZnCl2 and FeCl2 in aqueous HCl media. The properties of this magnetic adsorbent were examined by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), infrared spectrometer (FT-IR) and BET surface area measurements. Various factors influencing the adsorption of Zn(II) ion such as initial concentration of metal ions, the amount of adsorbent, pH value of the solutions, the concentration of coexisting iron ion were investigated by batch experiments. The results indicated that the adsorption equilibrium data obeyed the Freundlich model with maximum adsorption capacities for Zn(II) to 169.5mg/g. The maximum adsorption occurred at pH 5±0.1 and Fe(II) interferences had no obvious influence. This work provides a potential and unique technique for zinc ion removal from hot-dip galvanizing pickling waste. Copyright © 2015 Elsevier Inc. All rights reserved.

Bioelements in hair of children with selected neurological disorders.

PubMed

Józefczuk, Jan; Kasprzycka, Wiktoria; Czarnecki, Rafał; Graczyk, Alfreda; Józefczuk, Paweł; Krzysztof, Magda; Lampart, Urszula; Mrozowska-Ząbek, Ewa; Surdy, Weronika; Kwiatkowska-Graczyk, Róża

2017-01-01

We have analyzed concentrations of magnesium (Mg), calcium (Ca), copper (Cu), zinc (Zn) and iron (Fe) in hair of a group of 82 children with mental retardation, in which 9 patients suffered from epilepsy, 18 from the Down's syndrome and 55 from cerebral palsy. Girls comprised little over 50% of the patients. In the group of boys with epilepsy, we found Mg, Ca, Cu and Fe deficiency, and normal level of Zn. In the group of girls with epilepsy, apart from low Fe concentration, a high level of Ca, Mg, Zn, and Cu was noted. For girls with the Down's syndrome, a high or normal level of Ca, Mg, Zn and Cu was found, whereas the Fe concentration varied and presented itself in a non-characteristic way. Both groups of children with cerebral palsy, i.e. boys and girls, displayed low Fe concentration in their hair; low Cu level was found in older patients as well. In this group of patients, we also noted high concentrations of Ca, Mg and Zn in girls and normal in boys. A high concentration of Ca in girls with cerebral palsy requires separate analysis. The obtained results could be useful as guidance in the direction and determination of the amount of possible patient nutritional supplementation.

Disturbances to metal partitioning during toxicity testing of iron(II)-rich estuarine pore waters and whole sediments.

PubMed

Simpson, Stuart L; Batley, Graeme E

2003-02-01

Metal partitioning is altered when suboxic estuarine sediments containing Fe(II)-rich pore waters are disturbed during collection, preparation, and toxicity testing. Experiments with model Fe(II)-rich pore waters demonstrated the rates at which adsorptive losses of Cd, Cu, Ni, Mn, Pb, and Zn occur upon exposure to air. Experiments with Zn-contaminated estuarine sediments demonstrated large and often unpredictable changes to metal partitioning during sediment storage, removal of organisms, and homogenization before testing. Small modifications to conditions, such as aeration of overlying waters, caused large changes to the metal partitioning. Disturbances caused by sediment collection required many weeks for reestablishment of equilibrium. Bioturbation by benthic organisms led to oxidation of pore-water Fe(II) and lower Zn fluxes because of the formation of Fe hydroxide precipitates that adsorb pore-water Zn. For five weeks after the addition of organisms to sediments, Zn fluxes increased slowly as the organisms established themselves in the sediments, indicating that the establishment of equilibrium was not rapid. The results are discussed in terms of the dynamic nature of suboxic, Fe(II)-rich estuarine sediments, how organisms perturb their environment, and the importance of understanding chemistry in toxicity testing with whole sediments or pore water. Recommendations are provided for the handling of sediments for toxicity testing.

A Zn isotope perspective on the rise of continents.

PubMed

Pons, M-L; Fujii, T; Rosing, M; Quitté, G; Télouk, P; Albarède, F

2013-05-01

Zinc isotope abundances are fairly constant in igneous rocks and shales and are left unfractionated by hydrothermal processes at pH < 5.5. For that reason, Zn isotopes in sediments can be used to trace the changing chemistry of the hydrosphere. Here, we report Zn isotope compositions in Fe oxides from banded iron formations (BIFs) and iron formations of different ages. Zinc from early Archean samples is isotopically indistinguishable from the igneous average (δ(66) Zn ~0.3‰). At 2.9-2.7 Ga, δ(66) Zn becomes isotopically light (δ(66) Zn < 0‰) and then bounces back to values >1‰ during the ~2.35 Ga Great Oxygenation Event. By 1.8 Ga, BIF δ(66) Zn has settled to the modern value of FeMn nodules and encrustations (~0.9‰). The Zn cycle is largely controlled by two different mechanisms: Zn makes strong complexes with phosphates, and phosphates in turn are strongly adsorbed by Fe hydroxides. We therefore review the evidence that the surface geochemical cycles of Zn and P are closely related. The Zn isotope record echoes Sr isotope evidence, suggesting that erosion starts with the very large continental masses appearing at ~2.7 Ga. The lack of Zn fractionation in pre-2.9 Ga BIFs is argued to reflect the paucity of permanent subaerial continental exposure and consequently the insignificant phosphate input to the oceans and the small output of biochemical sediments. We link the early decline of δ(66) Zn between 3.0 and 2.7 Ga with the low solubility of phosphate in alkaline groundwater. The development of photosynthetic activity at the surface of the newly exposed continents increased the oxygen level in the atmosphere, which in turn triggered acid drainage and stepped up P dissolution and liberation of heavy Zn into the runoff. Zinc isotopes provide a new perspective on the rise of continents, the volume of carbonates on continents, changing weathering conditions, and compositions of the ocean through time. © 2013 Blackwell Publishing Ltd.

The potential of lentil (Lens culinaris L.) as a whole food for increased selenium, iron, and zinc intake: Preliminary results from a three year study

USDA-ARS?s Scientific Manuscript database

Micronutrient malnutrition, especially selenium (Se), iron (Fe), and zinc (Zn) deficiency, is a major global health problem. Previous attempts to prevent micronutrient malnutrition through food fortification, supplementation, and enrichment of staple crops has had limited success. Canadian grown len...

Chemical and biological processes for multi-metal extraction from waste printed circuit boards of computers and mobile phones.

PubMed

Shah, Monal B; Tipre, Devayani R; Dave, Shailesh R

2014-11-01

E-waste printed circuit boards (PCB) of computers, mobile-phones, televisions, LX (LongXiang) PCB in LED lights and bulbs, and tube-lights were crushed to ≥250 µm particle size and 16 different metals were analysed. A comparative study has been carried out to evaluate the extraction of Cu-Zn-Ni from computer printed circuit boards (c-PCB) and mobile-phone printed circuit boards (m-PCB) by chemical and biological methods. Chemical process showed the extraction of Cu-Zn-Ni by ferric sulphate was best among the studied chemical lixiviants. Bioleaching experiments were carried out with the iron oxidising consortium, which showed that when E-waste and inoculum were added simultaneously in the medium (one-step process); 60.33% and 87.50% Cu, 75.67% and 85.67% Zn and 71.09% and 81.87% Ni were extracted from 10 g L(-1) of c-PCB and m-PCB, respectively, within 10-15 days of reaction time. Whereas, E-waste added after the complete oxidation of Fe(2+) to Fe(3+) iron containing medium (two-step process) showed 85.26% and 99.99% Cu, 96.75% and 99.49% Zn and 93.23% and 84.21% Ni extraction from c-PCB and m-PCB, respectively, only in 6-8 days. Influence of varying biogenerated Fe(3+) and c-PCB concentrations showed that 16.5 g L(-1) of Fe(3+) iron was optimum up to 100 g L(-1) of c-PCB. Changes in pH, acid consumed and redox potential during the process were also studied. The present study shows the ability of an eco-friendly process for the recovery of multi-metals from E-waste even at 100 g L(-1) printed circuit boards concentration. © The Author(s) 2014.

Total and labile metals in surface sediments of the tropical river-estuary system of Marabasco (Pacific coast of Mexico): Influence of an iron mine.

PubMed

Marmolejo-Rodríguez, Ana Judith; Prego, Ricardo; Meyer-Willerer, Alejandro; Shumilin, Evgueni; Cobelo-García, Antonio

2007-01-01

Marabasco is a tropical river-estuary system comprising the Marabasco river and the Barra de Navidad Lagoon. The river is impacted by the Peña Colorada iron mine, which produces 3.5 million tons of pellets per year. Thirteen surface sediment samples were collected in May 2005 (dry season) in order to establish background levels of Al, Cd, Co, Cu, Fe, Ni, Pb, and Zn in the system and to ascertain the potential mobility of metals in the sediments. Analyses were carried out in the fraction finer than 63 microm, and labile metals extracted according the BCR procedure. Certified reference materials were used for validation of methods. Total concentrations of Cd, Co, Cu, Ni, Pb, and Zn were in the range of 0.05-0.34, 6-95, 0.7-31, 9-26, 2-18, and 53-179 mgkg(-1), respectively; Al and Fe ranges of 24-127, and 26-69 mgg(-1) correspondingly. Cadmium was found to be significantly labile in the sediments (20-100%), followed by Co (0-35%), Ni (3-16%) and Zn (0-25%), whereas the labile fraction for Cu, Fe and Pb was almost negligible (<4%). According with the total metal concentrations, background levels and normalised enrichment factors (NEF) of the metals studied, the impact of the Peña Colorada iron mine on the Marabasco system is lower than expected when compared with other similar World systems influenced by mining activities.

Determination of Microelements in Human Milk and Infant Formula Without Digestion by ICP-OES.

PubMed

Đurović, Dijana; Milisavljević, Branka; Nedović-Vuković, Mirjana; Potkonjak, Branislav; Spasić, Snežana; Vrvić, Miroslav

2017-06-01

The concentrations of zinc (Zn), iron (Fe) and copper (Cu) in both human milk and infant formula were determined using a new sample preparation method, by inductively coupled plasma - optical emission spectometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). Human milk samples were diluted in ultrapure water. The infant formula of powder samples (suitable for an infant 1-6 months of age) and standard reference material (SRM-1849) were analyzed in parallel. The results have shown that FAAS method was more sensitive for Fe determination in human milk while ICP-OES was more sensitive for both Zn and Cu detection. The limit of quantification for both Zn and Cu was 5 μg L-1 and 10 μg L-1 for Fe and the recovery for Zn, Fe and Cu was ranged from 90% to 94%, 97% to 103% and 90% to 102%, respectively. Mean concentrations of Zn, Fe, and Cu in human milk samples were 5.35, 0.47 and 0.83 mg L-1, respectively while these values in infant formula were ranged from 3.52-4.75 mg L-1, 3.37-4.56 mg L-1 and 0.28-0.41 mg L-1, respectively. Despite the sample complexity, the proposed method using dilution of milk samples with water was simple, rapid, effective and accurate. ICP-OES was a better method for Zn determination while FAAS was a better method for Fe determination. In the case of Cu both methods were comparable.

Toxicity of Metals to a Freshwater Ostracod: Stenocypris major

PubMed Central

Shuhaimi-Othman, Mohammad; Yakub, Nadzifah; Ramle, Nur-Amalina; Abas, Ahmad

2011-01-01

Adults of freshwater ostracod Stenocypris major (Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration in S. major increases with exposure to increasing concentrations, and Cd was the most toxic to S. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC50 values for metals for this species with those for other freshwater crustacean reveals that S. major is equally or more sensitive to metals than most other tested crustacean. PMID:21559091

Enrichment of Zinc in Galactic Chemodynamical Evolution Models

NASA Astrophysics Data System (ADS)

Hirai, Yutaka; Saitoh, Takayuki R.; Ishimaru, Yuhri; Wanajo, Shinya

2018-03-01

The heaviest iron-peak element Zinc (Zn) has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show an increasing trend of [Zn/Fe] ratios toward lower metallicity. However, the enrichment of Zn in galaxies is not well understood due to poor knowledge of astrophysical sites of Zn, as well as metal mixing in galaxies. Here we show possible explanations for the observed trend by taking into account electron-capture supernovae (ECSNe) as one of the sources of Zn in our chemodynamical simulations of dwarf galaxies. We find that the ejecta from ECSNe contribute to stars with [Zn/Fe] ≳ 0.5. We also find that scatters of [Zn/Fe] in higher metallicities originate from the ejecta of type Ia supernovae. On the other hand, it appears difficult to explain the observed trends if we do not consider ECSNe as a source of Zn. These results come from an inhomogeneous spatial metallicity distribution due to the inefficiency of the metal mixing. We find that the optimal value of the scaling factor for the metal diffusion coefficient is ∼0.01 in the shear-based metal mixing model in smoothed particle hydrodynamics simulations. These results suggest that ECSNe could be one of the contributors of the enrichment of Zn in galaxies.

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

Coussy, Samuel; Grangeon, Sylvain; Bataillard, Philippe

The prediction of the long term trace element mobility in anthropogenic soils would be a way to anticipate land management and should help in reusing slightly contaminated materials. In the present study, iron (Fe) and zinc (Zn) status evolution was investigated in a 100-year old Technosol. The site of investigation is an old brownfield located in the Nord-Pas-de-Calais region (France) which has not been reshaped since the beginning of the last century. The whole soil profile was sampled as a function of depth, and trace elements mobility at each depth was determined by batch leaching test. A specific focus onmore » Fe and Zn status was carried out by bulk analyses, such as selective dissolution, X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). Fe and Zn status in the profile samples was also studied using laterally resolved techniques such as μ-particle induced X-ray emission (μ-PIXE) and μ-Rutherford backscattering spectroscopy (μ-RBS). The results indicate that (i) Fe is mainly under Fe(III) form, except a minor contribution of Fe(II) in the deeper samples, (ii) some Fe species inherited from the past have been weathered and secondary minerals are constituted of metal-bearing sulphates and Fe (hydr)oxides, (iii) ferrihydrite is formed during pedogenesis (iv) 20 to 30% more Fe (hydr)oxides are present in the surface than in depth and (v) Zn has tetrahedral coordination and is sorbed to phases of increasing crystallinity when depth increases. Zn-bearing phases identified in the present study are: complex Fe, Mn, Zn sulphides, sulphates, organic matter, and ferrihydrite. Soil formation on such material does not induce a dramatic increase of Zn solubility since efficient scavengers are concomitantly formed in the system. However, Technosols are highly heterogeneous and widely differ from one place to another. The behavior examined in this study is not generic and will depend on the type of Technosol and on the secondary minerals formed as well as on the nature and amount of organic matter.« less

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents by X-ray photoelectron spectroscopy and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Siriwardane, Ranjani V.; Poston, James A.

1993-05-01

Characterization of copper oxides, iron oxides, and zinc copper ferrite desulfurization sorbents was performed by X-ray photoelectron spectroscopy and scanning electron microscopy/energy-dispersive spectroscopy at temperatures of 298 to 823 K. Analysis of copper oxides indicated that the satellite structure of the Cu22p region was absent in the Cu(I) state but was present in the Cu(II) state. Reduction of CuO at room temperature was observed when the ion gauge was placed close to the sample. The satellite structure was absent in all the copper oxides at 823 K in vacuum. Differentiation of the oxidation state of copper utilizing both Cu(L 3M 4,5M 4,5) X-ray-induced Auger lines and Cu2p satellite structure, indicated that the copper in zinc copper ferrite was in the + 1 oxidation state at 823 K. This + 1 state of copper was not significantly changed after exposure to H 2, CO, and H 2O. There was an increase in Cu/Zn ratio and a decrease in Fe/Zn ratio on the surface of zinc copper ferrite at 823 K compared to that at room temperature. These conditions of copper offered the best sulfidation equilibrium for the zinc copper ferrite desulfurization sorbent. Analysis of iron oxides indicated that there was some reduction of both Fe 2O 3 and FeO at 823K. The iron in zinc copper ferrite was similar to that of Fe 2O 3 at room temperature but there was some reduction of this Fe(III) state to Fe(II) at 823 K. This reduction was more enhanced in the presence of H 2 and CO. Reduction to Fe(II) may not be desirable for the lifetime of the sorbent.

Acute and subacute response of iron, zinc, copper and selenium in pigs experimentally infected with Actinobacillus pleuropneumoniae.

PubMed

Humann-Ziehank, Esther; Menzel, Anne; Roehrig, Petra; Schwert, Barbara; Ganter, Martin; Hennig-Pauka, Isabel

2014-10-01

This study was performed to characterise the response of iron (Fe), zinc (Zn), copper (Cu) and selenium (Se) in bacterial-induced porcine acute phase reaction (APR). Twenty piglets were challenged by aerosolic infection with Actinobacillus pleuropneumoniae (A.pp.) serotype 2, ten piglets serving as controls. Blood sampling was done initially and at day 4 and 21 after infection, collection of liver tissue was done at day 21 (autopsy). A.pp.-infection caused fever and respiratory symptoms. APR at day 4 after infection was marked by an increase in total white blood cells, granulocytes and monocytes in whole blood samples and an increase in globulin/albumin ratio (G/A), α2-globulins, C-reactive protein, haptoglobin, ceruloplasmin (Cp), Cu and Se in serum. Concurrently, there was a decrease in haemoglobin (Hb) and packed cell volume (PCV) in whole blood as well as a decrease in albumin, transferrin, total iron binding capacity and Fe in serum and Zn in plasma. The subacute stage at day 21 was characterised by progressively increased concentrations of G/A, β-globulins and γ-globulins reflecting the specific immune reaction. Hb and PCV showed further decreases, all other parameters returned to the initial concentrations. Glutathione peroxidase activity in plasma and liver tissue remained unaffected by A.pp.-infection. The liver concentration (day 21) of Zn was found to be higher, that of Se was lower in the A.pp.-group, whereas hepatic concentrations of Cu and Fe were not affected by A.pp.-infection. In summary, the acute and subacute stages of A.pp.-infection were accurately characterised by the APR-related parameters. Se was only marginally affected by the A.pp.-infection. The elevated plasma Cu concentration may be a side effect of the transient hepatic induction of Cp synthesis. Zn responded, being distinctly reduced in plasma and probably having been sequestered in the liver tissue. Reduction in serum Fe can be regarded as an unspecific defence mechanism in A.pp.-infection to withdraw Fe from bacterial acquisition systems.

Molecular mapping of the grain iron and zinc concentration, protein content and thousand kernel weight in wheat (Triticum aestivum L.)

PubMed Central

Krishnappa, Gopalareddy; Chaudhary, Swati; Ahlawat, Arvind Kumar; Singh, Santosh Kumar; Shukla, Ram Bihari; Jaiswal, Jai Prakash; Singh, Gyanendra Pratap; Solanki, Ishwar Singh

2017-01-01

Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (Triticum dicoccon PI94624/Aegilops squarrosa [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (QGFe.iari-2A, QGFe.iari-5A, QGFe.iari-7A and QGFe.iari-7B) for Fe, five QTLs (QGZn.iari-2A, QGZn.iari-4A, QGZn.iari-5A, QGZn.iari-7A and QGZn.iari-7B) for Zn, two QTLs (QGpc.iari-2A and QGpc.iari-3A) for PC, and five QTLs (QTkw.iari-1A, QTkw.iari-2A, QTkw.iari-2B, QTkw.iari-5B and QTkw.iari-7A) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. QGpc.iari-2A was consistently expressed in all the six environments, whereas, QGFe.iari-7B and QGZn.iari-2A were identified in two environments each apart from pooled mean. QTkw.iari-2A and QTkw.iari-7A, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of Xgwm359-Xwmc407 on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (Xgwm382-Xgwm359). Two more regions on 5A (Xgwm126-Xgwm595) and 7A (Xbarc49-Xwmc525) were found to be associated with both Fe and Zn. A QTL for TKW was identified (Xwmc525-Xbarc222) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding. PMID:28384292

Fe1-xZnxS ternary solid solution as an efficient Fenton-like catalyst for ultrafast degradation of phenol.

PubMed

Gao, Jing; Liu, Yutang; Xia, Xinnian; Wang, Longlu; Dong, Wanyue

2018-07-05

Heterogeneous Fenton-like system has been proved to be an promising alternative to Fenton system due to its easy separation. However, it's a challenge to design heterogeneous Fenton-like catalysts with high activity and great durability. Here, ternary solid solution Fe 1-x Zn x S were prepared via hydrothermal synthesis as heterogeneous Fenton-like catalysts. The Fe 0.7 Zn 0.3 S sample exhibited state of the art activity for yielding OH by H 2 O 2 decomposition, and the ultrafast degradation of phenol was achieved in 4 min at initial acidic condition under room temperature. The phenol degradation rate constant of Fe 0.7 Zn 0.3 S was 99 and 70 times of ZnS and FeS, respectively. Further, we show that the unique structural configuration of iron atoms, the formation of FeS 2 -pyrite with (200) plane, are responsible for the excellent activity. The intermediate products were identified by LC-MS and a possible pathway was accordingly proposed to elucidate the mechanism of phenol degradation by OH. Overall, this work provides an idea for the rational design of the relevant heterogeneous Fenton-like catalysts. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Iron Impurity on the Phase Composition, Structure and Properties of Magnesium Alloys Containing Manganese and Aluminum

NASA Astrophysics Data System (ADS)

Volkova, E. F.

2017-07-01

Results of a study of the interaction between iron impurity and manganese and aluminum alloying elements during formation of phase composition in alloys of the Mg - Mn, Mg - Al, Mg - Al - Mn, and Mg - Al - Zn - Mn systems are presented. It is proved that this interaction results in introduction of Fe into the intermetallic phase. The phase compositions of model magnesium alloys and commercial alloys MA2-1 and MA5 are studied. It is shown that both manganese and aluminum may bind the iron impurity into phases. Composite Fe-containing intermetallic phases of different compositions influence differently the corrosion resistance of magnesium alloys.

Synthesis and characterization of sulfate and dodecylbenzenesulfonate intercalated zinc iron layered double hydroxides by one-step coprecipitation route

NASA Astrophysics Data System (ADS)

Zhang, Hui; Wen, Xing; Wang, Yingxia

2007-05-01

Inorganic sulfate- and organic dodecylbenzenesulfonate (DBS)-intercalated zinc-iron layered double hydroxides (LDHs) materials were prepared by one-step coprecipitation method from a mixed salt solutions containing Zn(II), Fe(II) and Fe(III) salts. The as-prepared samples have been characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), low-temperature nitrogen adsorption, scanning electron microscopy (SEM), inductively coupled plasma emission spectroscopy (ICP), and Mössbauer spectroscopy (MS). The XRD analyses demonstrate the typical LDH-like layered structural characteristics of both products. The room temperature MS results reveal the characteristics of both the Fe(II) and Fe(III) species for SO 42--containing product, while only the Fe(III) characteristic for DBS-containing one. The combination characterization results and Rietveld analysis illustrate that the SO 42--containing product possesses the Green Rust two (GR2)-like crystal structure with an approximate chemical composition of [Zn 0.435·Fe II0.094·Fe III0.470·(OH) 2]·(SO 42-) 0.235·1.0H 2O, while the DBS-containing one exhibits the common LDH compound-like structure. The contact angle measurement indicates the evident hydrophobic properties of DBS-containing nanocomposite, compared with SO 42--containing product, due to the modification of the internal and external surface of LDHs by the organic hydrophobic chain of DBS.

Estimated daily intake of Fe, Cu, Ca and Zn through common cereals in Tehran, Iran.

PubMed

Kashian, S; Fathivand, A A

2015-06-01

This paper presents the findings of study undertaken to estimate the dietary intake of iron (Fe), copper (Cu), calcium (Ca) and zinc (Zn) through common cereals in Tehran, Iran. 100 samples of rice, wheat and barley were collected from various brands between August and October 2013. The samples were analyzed performing instrumental neutron activation analysis (INAA). The dietary intake for adults was estimated by a total cereal study. Calculations were carried out on the basis of the reported adults' average food consumption rate data. The total daily intake estimated in mgd(-1) for Tehran population were 3.6 (Fe), 10.2 (Zn), 0.3 (Cu) and 234.5 (Ca). Wheat showed the highest contribution to Zn, Cu and Ca intakes. Furthermore, intakes were compared with recommended dietary allowance (RDA). Zn total intake (10.2mgd(-1)) was comparable with RDA values for males (11mgd(-1)) and was higher than recommended value for females (8mgd(-1)). The intakes of other studied elements were below the respective RDAs. Copyright © 2014 Elsevier Ltd. All rights reserved.

THE ORIGIN OF LOW [α/Fe] RATIOS IN EXTREMELY METAL-POOR STARS

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

Kobayashi, Chiaki; Ishigaki, Miho N.; Tominaga, Nozomu

2014-04-10

We show that the low ratios of α elements (Mg, Si, and Ca) to Fe recently found for a small fraction of extremely metal-poor stars can be naturally explained with the nucleosynthesis yields of core-collapse supernovae, i.e., 13-25 M {sub ☉} supernovae, or hypernovae. For the case without carbon enhancement, the ejected iron mass is normal, consistent with observed light curves and spectra of nearby supernovae. On the other hand, the carbon enhancement requires much smaller iron production, and the low [α/Fe] of carbon-enhanced metal-poor stars can also be reproduced with 13-25 M {sub ☉} faint supernovae or faint hypernovae.more » Iron-peak element abundances, in particular Zn abundances, are important to put further constraints on the enrichment sources from galactic archaeology surveys.« less

SYNTHESIS, REACTIVITY, AND CATALYTIC BEHAVIOR OF IRON/ZINC-CONTAINING SPECIES INVOLVED IN OXIDATION OF HYDROCARBONS UNDER GIF-TYPE CONDITIONS. (R823377)

EPA Science Inventory

The present study explores the nature and reactivity of iron- and zinc-containing species
generated in hydrocarbon-oxidizing Gif(IV)-type solutions Fe catalyst/Zn/O-2 in pyridine/acetic acid
(10:1 v/v). The ultimate goal of this investigation is to unravel the role of metal...

Kinetic control on Zn isotope signatures recorded in marine diatoms

NASA Astrophysics Data System (ADS)

Köbberich, Michael; Vance, Derek

2017-08-01

Marine diatoms dominate the oceanic cycle of the essential micronutrient zinc (Zn). The stable isotopes of zinc and other metals are increasingly used to understand trace metal micronutrient cycling in the oceans. One clear feature of the early isotope data is the heavy Zn isotope signature of the average oceanic dissolved pool relative to the inputs, potentially driven by uptake of light isotopes into phytoplankton cells and export to sediments. However, despite the fact that diatoms strip Zn from surface waters across the Antarctic polar front in the Southern Ocean, the local upper ocean is not isotopically heavy. Here we use culturing experiments to quantify the extent of Zn isotope fractionation by diatoms and to elucidate the mechanisms driving it. We have cultured two different open-ocean diatom species (T. oceanica and Chaetoceros sp.) in a series of experiments at constant medium Zn concentration but at bioavailable medium Fe ranging from limiting to replete. We find that T. oceanica can maintain high growth rates and Zn uptake rates over the full range of bioavailable iron (Fe) investigated, and that the Zn taken up has a δ66Zn that is unfractionated relative to that of the bioavailable free Zn in the medium. The studied representative of the genus Chaetoceros, on the other hand, shows more significantly reduced Zn uptake rates at low Fe and records more variable biomass δ66Zn signatures, of up to 0.85‰ heavier than the medium. We interpret the preferential uptake of heavy isotopes at extremely low Zn uptake rates as potentially due to either of the following two mechanisms. First, the release of extracellular polymeric substances (EPS), at low Fe levels, may preferentially scavenge heavy Zn isotopes. Second, the Zn uptake rate may be slow enough to establish pseudo-equilibrium conditions at the transporter site, with heavy Zn isotopes forming more stable surface complexes. Thus we find that, in our experiments, Fe-limitation exerts a key control that not only limits diatom growth, but also affects the Zn uptake physiology of diatoms. Uptake of heavy isotopes occurs under Fe-limiting conditions that drive extremely low Zn uptake rates. On the other hand, more rapid Zn uptake rates result in biomass that is indistinguishable from the external bioavailable free Zn pool. These experimental results can, in principle, explain the range of Zn isotopic compositions found in the real surface ocean, given the geographically variable interplay between Fe-limitation, Zn uptake rates, and the degree of organic complexation of oceanic Zn.

Trace Mineral Micronutrients and Chronic Periodontitis-a Review.

PubMed

Gaur, Sumit; Agnihotri, Rupali

2017-04-01

Trace mineral micronutrients are imperative for optimum host response. Populations worldwide are prone to their insufficiency owing to lifestyle changes or poor nutritional intake. Balanced levels of trace minerals like iron (Fe), zinc (Zn), selenium (Se) and copper (Cu) are essential to prevent progression of chronic conditions like periodontitis. Their excess as well as deficiency is detrimental to periodontal health. This is specifically true in relation to Fe. Furthermore, some trace elements, e.g. Se, Zn and Cu are integral components of antioxidant enzymes and prevent reactive oxygen species induced destruction of tissues. Their deficiency can worsen periodontitis associated with systemic conditions like diabetes mellitus. With this background, the present review first focusses on the role of four trace minerals, namely, Fe, Zn, Se and Cu in periodontal health followed by an appraisal of the data from case control studies related to their association with chronic periodontitis.

Preferential uptake of ammonium ions by zinc ferrocyanide

NASA Technical Reports Server (NTRS)

Braterman, P. S.; Arrhenius, G.; Hui, S.; Paplawsky, W.; Miller, S. L. (Principal Investigator)

1995-01-01

The concentration of ammonia from dilute aqueous solution could have facilitated many prebiotic reactions. This may be especially true if this concentration involves incorporation into an organized medium. We have shown that (unlike iron(III) ferrocyanide) zinc ferrocyanide,Zn2Fe(CN)6 xH2O, preferentially takes up ammonium ions from 0.01 M NH4Cl to give the known material Zn3(NH4)2[Fe(CN)6]2 xH2O, even in the presence of 0.01 M KCl. KCl alone gave Zn3K2[Fe(CN)6]2 xH2O. Products were characterized by elemental (CHN) analysis and powder X-ray diffraction (XRD). We attribute the remarkable specificity for the ammonium ion to the open framework of the product, which offers enough space for hydrogen-bonded ammonium ions, and infer that other inorganic materials with internal spaces rich in water may show a similar preference.

Iron and zinc isotope fractionation during uptake and translocation in rice (Oryza sativa) grown in oxic and anoxic soils

NASA Astrophysics Data System (ADS)

Arnold, Tim; Markovic, Tamara; Kirk, Guy J. D.; Schönbächler, Maria; Rehkämper, Mark; Zhao, Fangjie J.; Weiss, Dominik J.

2015-11-01

Stable isotope fractionation is emerging quickly as a powerful novel technique to study metal uptake and translocation in plants. Fundamental to this development is a thorough understanding of the processes that lead to isotope fractionation under differing environmental conditions. In this study, we investigated Zn and Fe isotope fractionation in rice grown to maturity in anaerobic and aerobic soils under greenhouse conditions. The overall Zn isotope fractionation between the soil and above ground plant material was negligible in aerobic soil but significant in anaerobic soil with isotopically lighter Zn in the rice plant. The observed range of fractionation is in line with previously determined fractionations of Zn in rice grown in hydroponic solutions and submerged soils and emphasizes the effect of taking up different chemical forms of Zn, most likely free and organically complexed Zn. The Zn in the grain was isotopically lighter than in the rest of the above ground plant in rice grown in aerobic and anaerobic soils alike. This suggests that in the course of the grain loading and during the translocation within the plant important biochemical and/or biophysical processes occur. The isotope fractionation observed in the grains would be consistent with an unidirectional controlled transport from shoot to grain with a fractionation factor of α ≈ 0.9994. Iron isotopes showed an isotopic lighter signature in shoot and grain compared to the bulk soil or the leachate in aerobic and anaerobic soils alike. The negative direction of isotopic fractionation is consistent with possible changes in the redox state of Fe occurring during the uptake and translocation processes. The isotope fractionation pattern between shoots and grain material are different for Zn and Fe which finally suggests that different mechanisms operate during translocation and grain-loading in rice for these two key micronutrients.

Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

PubMed Central

Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

2015-01-01

Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe2+ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni2+ uptake at roots; however, the underlying mechanism of Ni2+ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni2+ absorption and (ii) Zn2+ inhibits Ni2+ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency. PMID:25923075

Simple and novel electrochemical sensor for the determination of tetracycline based on iron/zinc cations-exchanged montmorillonite catalyst.

PubMed

Gan, Tian; Shi, Zhaoxia; Sun, Junyong; Liu, Yanming

2014-04-01

A simple and novel electrochemical sensor for the determination of tetracycline (TC), a kind of antibiotic that may induce residue in the food chain, was developed by the modification of iron/zinc cation-exchanged montmorillonite (Fe/Zn-MMT) catalyst on glassy carbon electrode (GCE). The morphology and the structure of the Fe/Zn-MMT nanomaterial were characterized by scanning electron microscopy and X-ray diffraction, respectively. The results of electrochemical experiments demonstrated that the sensor exhibited excellent electrocatalytic activity to the oxidation of TC in the presence of sodium dodecyl sulfate. The sensor displayed a wide linear range from 0.30 to 52.0 μM and a low detection limit of 0.10 μM by using the derivative differential pulse voltammetry. Moreover, the electrochemical sensor was applied to the detection of TC in feedstuff and meat samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Three-dimensional atlas of iron, copper, and zinc in the mouse cerebrum and brainstem.

PubMed

Hare, Dominic J; Lee, Jason K; Beavis, Alison D; van Gramberg, Amanda; George, Jessica; Adlard, Paul A; Finkelstein, David I; Doble, Philip A

2012-05-01

Atlases depicting molecular and functional features of the brain are becoming an integral part of modern neuroscience. In this study we used laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantitatively measure iron (Fe), copper (Cu), and zinc (Zn) levels in a serially sectioned C57BL/6 mouse brain (cerebrum and brainstem). Forty-six sections were analyzed in a single experiment of approximately 158 h in duration. We constructed a 46-plate reference atlas by aligning quantified images of metal distribution with corresponding coronal sections from the Allen Mouse Brain Reference Atlas. The 46 plates were also used to construct three-dimensional models of Fe, Cu, and Zn distribution. This atlas represents the first reconstruction of quantitative trace metal distribution through the brain by LA-ICPMS and will facilitate the study of trace metals in the brain and help to elucidate their role in neurobiology.

Examining Two Sets of Introgression Lines in Rice (Oryza sativa L.) Reveals Favorable Alleles that Improve Grain Zn and Fe Concentrations

PubMed Central

Hu, Xia; Cheng, Li-Rui; Xu, Jian-Long; Shi, Yu-Min; Li, Zhi-Kang

2015-01-01

In the modern world, the grain mineral concentration (GMC) in rice (Oryza sativa L.) not only includes important micronutrient elements such as iron (Fe) and zinc (Zn), but it also includes toxic heavy metal elements, especially cadmium (Cd) and lead (Pb). To date, the genetic mechanisms underlying the regulation of GMC, especially the genetic background and G × E effects of GMC, remain largely unknown. In this study, we adopted two sets of backcross introgression lines (BILs) derived from IR75862 (a Zn-dense rice variety) as the donor parent and two elite indica varieties, Ce258 and Zhongguangxiang1, as recurrent parents to detect QTL affecting GMC traits including Fe, Zn, Cd and Pb concentrations in two environments. We detected a total of 22 loci responsible for GMC traits, which are distributed on all 12 rice chromosomes except 5, 9 and 10. Six genetic overlap (GO) regions affecting multiple elements were found, in which most donor alleles had synergistic effects on GMC. Some toxic heavy metal-independent loci (such as qFe1, qFe2 and qZn12) and some regions that have opposite genetic effects on micronutrient (Fe and Zn) and heavy metal element (Pb) concentrations (such as GO-IV) may be useful for marker-assisted biofortification breeding in rice. We discuss three important points affecting biofortification breeding efforts in rice, including correlations between different GMC traits, the genetic background effect and the G × E effect. PMID:26161553

Fe2 PO5 -Encapsulated Reverse Energetic ZnO/Fe2 O3 Heterojunction Nanowire for Enhanced Photoelectrochemical Oxidation of Water.

PubMed

Qin, Dong-Dong; He, Cai-Hua; Li, Yang; Trammel, Antonio C; Gu, Jing; Chen, Jing; Yan, Yong; Shan, Duo-Liang; Wang, Qiu-Hong; Quan, Jing-Jing; Tao, Chun-Lan; Lu, Xiao-Quan

2017-07-10

Zinc oxide is regarded as a promising candidate for application in photoelectrochemical water oxidation due to its higher electron mobility. However, its instability under alkaline conditions limits its application in a practical setting. Herein, we demonstrate an easily achieved wet-chemical route to chemically stabilize ZnO nanowires (NWs) by protecting them with a thin layer Fe 2 O 3 shell. This shell, in which the thickness can be tuned by varying reaction times, forms an intact interface with ZnO NWs, thus protecting ZnO from corrosion in a basic solution. The reverse energetic heterojunction nanowires are subsequently activated by introducing an amorphous iron phosphate, which substantially suppressed surface recombination as a passivation layer and improved photoelectrochemical performance as a potential catalyst. Compared with pure ZnO NWs (0.4 mA cm -2 ), a maximal photocurrent of 1.0 mA cm -2 is achieved with ZnO/Fe 2 O 3 core-shell NWs and 2.3 mA cm -2 was achieved for the PH 3 -treated NWs at 1.23 V versus RHE. The PH 3 low-temperature treatment creates a dual function, passivation and catalyst layer (Fe 2 PO 5 ), examined by X-ray photoelectron spectroscopy, TEM, photoelectrochemical characterization, and impedance measurements. Such a nano-composition design offers great promise to improve the overall performance of the photoanode material. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-temperature hematite and spinel phases in iron-rich slags produced in shales above burned coal seams

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

Modreski, P.J.; Herring, J.R.

1985-01-01

Ultrametamorphic effects (1300+ /sup 0/C) in shales above burned coal seams in the Powder River Basin, Wyoming, include the formation of droplets and stalactites of congealed iron-rich melt (40.3 wt.% SiO/sub 2/, 35.5% Fe as Fe/sub 2/O/sub 3/, 13.5% Al/sub 2/O/sub 3/, 2.2% MgO, 5.0% CaO, 0.3% MnO, 1.0% K/sub 2/O, 0.5% TiO/sub 2/, 1.3% P/sub 2/O/sub 5/, <0.2% Na/sub 2/O, 0.55% LOI, total 100.2%). This melt, quartz-normative and comparable to an iron-rich basalt, formed along fractures which served as chimneys for escape of burning gases; pyrite or other iron-rich concretions in the shale may have been the source ofmore » the iron in the melts. Oxide phases, dominantly intergrown hematite+magnetite, in the droplets reflect a high-T, low-P, high-f(O/sub 2/) environment. Hematite ranges from nearly pure Fe/sub 2/O/sub 3/ near the droplet rims (Hm-1) to Al- and Ti-rich in the interiors (Hm-2 to -5). Magnetite contains Mg and Al (Mt-1); in the droplet interiors it is richer in Mg and Al (Mt-2 = host+lamellae) and contains lamellae of exsolved hercynite spinel (Sp-1). Near droplet rims, hematite occurs with magnesioferrite spinel (Mf-1) enriched in Mn and Zn (up to 7 wt.% ZnO), a product of reaction with gases during cooling. Averaged microprobe analyses are provided.« less

Chemical fractionation of heavy metals in urban soils of Guangzhou, China.

PubMed

Lu, Ying; Zhu, Feng; Chen, Jie; Gan, Haihua; Guo, Yanbiao

2007-11-01

Knowledge of the total concentration of heavy metals is not enough to fully assess the environmental impact of urban soils. For this reason, the determination of metal speciation is important to evaluate their environment and the mobilization capacity. Sequential extraction technique proposed by the former European Community Bureau of Reference (BCR) was used to speciate Cd, Cu, Fe, Mn, Ni, Pb, and Zn in urban soils from Guangzhou into four operationally defined fractions: HOAc extractable, reducible, oxidizable, and residual. The Cu, Fe, Ni, and Zn were predominantly located in the residual fraction, Pb in the reducible fraction, and Cd and Mn within the HOAc extractable fraction. The order of Cd in each fraction was generally HOAc extractable > reducible > residual > oxidizable; Cu and Fe were residual > reducible > oxidizable > HOAc extractable; Mn was HOAc extractable > residual > reducible > oxidizable; Ni and Zn were residual > reducible > HOAc extractable > oxidizable; and Pb was reducible > residual > oxidizable > HOAc extractable. Cadmium was identified as being the most mobile of the elements, followed by Mn, Zn, Ni, Cu, Pb and Fe. Iron-Mn oxides can play an important role in binding Cd, Cu, Ni, Pb, and Zn and in decreasing their proportion associated with the residual fraction in the soils. With total concentrations of Cd, Cu, Ni, Pb, Zn, and Mn increase, these metals more easily release and may produce more negative effects on the urban environment.

Calcium biofortification of crops

USDA-ARS?s Scientific Manuscript database

More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

Effects of pH Value of the Electrolyte and Glycine Additive on Formation and Properties of Electrodeposited Zn-Fe Coatings

PubMed Central

2013-01-01

Environmentally friendly and cyanide-free sulfate bath under continuous current and the corrosion behavior of electrodeposits of zinc-iron alloys were studied by means of electrochemical tests in a solution of 3.5% NaCl in presence and absence of glycine. The effects of pH on the quality of Zn-Fe coatings were investigated in order to improve uniformity and corrosion protection performance of the coating films. The deposit morphology was analyzed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) was used to determine the preferred crystallographic orientations of the deposits. It was found that the uniformity and corrosion resistance of Zn-Fe coating films were strongly associated with pH of the coating electrolyte. To obtain the effect of pH on the film quality and corrosion performances of the films, the corrosion test was performed with potentiodynamic anodic polarization method. It was also observed that uniformity and corrosion resistivity of the coating films were decreased towards pH = 5 and then improved with increasing pH value of the electrolyte. The presence of glycine in the plating bath decreases the corrosion resistance of Zn-Fe coatings. PMID:23844388

Distribution of trace metals in surface seawater and zooplankton of the Bay of Bengal, off Rushikulya estuary, East Coast of India.

PubMed

Srichandan, Suchismita; Panigrahy, R C; Baliarsingh, S K; Rao B, Srinivasa; Pati, Premalata; Sahu, Biraja K; Sahu, K C

2016-10-15

Concentrations of trace metals such as iron (Fe), copper (Cu), zinc (Zn), cobalt (Co), nickel (Ni), manganese (Mn), lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), vanadium (V), and selenium (Se) were determined in seawater and zooplankton from the surface waters off Rushikulya estuary, north-western Bay of Bengal. During the study period, the concentration of trace metals in seawater and zooplankton showed significant spatio-temporal variation. Cu and Co levels in seawater mostly remained non-detectable. Other elements were found at higher concentrations and exhibited marked variations. The rank order distribution of trace metals in terms of their average concentration in seawater was observed as Fe>Ni>Mn>Pb>As>Zn>Cr>V>Se>Cd while in zooplankton it was Fe>Mn>Cd>As>Pb>Ni>Cr>Zn>V>Se. The bioaccumulation factor (BAF) of Fe was highest followed by Zn and the lowest value was observed with Ni. Results of correlation analysis discerned positive affinity and good relationship among the majority of the trace metals, both in seawater and zooplankton suggesting their strong affinity and coexistence. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxicity of Metals to a Freshwater Snail, Melanoides tuberculata

PubMed Central

Shuhaimi-Othman, M.; Nur-Amalina, R.; Nadzifah, Y.

2012-01-01

Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50 and LC50 increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50 values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L−1, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50 values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals. PMID:22666089

Cross-links (XL) and Zn action in ferritin related to an H-specific site

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

Yablonski, M.J.; Theil, E.C.

1991-03-15

Zn and subunit cross-links (F{sub 2}DNB) alter ferritin iron core formation in vivo and in vitro; the effect is observed in ferritins composed of two subunit types (H and L). Protein coats from sheep spleen ferritin (SSF) ({plus minus} XL), a model for a protein with H and L subunits (1:1), and horse spleen ferritin (HSF), a model for H deficient protein were reconstituted with Fe{sup 2+}, {plus minus} Zn, at pH 6.1 and 7.0 in order to investigate the effects of Zn and XLs on H and L subunits. Core formation was measured both as {Delta}A{sub 420} and themore » accessibility of Fe{sup 2+} to 1,10-phenanthroline. At pH 6.1, Zn decreased the {Delta}A{sub 420} in 1 min {ge} 87X (SSF) or 15X (HSF). XLs ({plus minus}Zn) decreased {Delta}A{sub 420} at 1 min similarly; at pH 7.0, Zn reduced {Delta}A{sub 420} at 1 min in SSF 3X with no effect on HSF. At both values of pH, Zn increased accessibility equally for SSF and HSF. The data indicate that : Zn has different effects on core formation measured as {Delta}A{sub 420} at 1 min or Fe{sup 2+} entry into ferritin; cross-links and Zn affects a common site involved in core formation; and Zn affects an H subunit-specific site which may involve histidine.« less

Acid Mine Drainage and Metal Sulfate Minerals in the Shasta Mining District, California

NASA Astrophysics Data System (ADS)

Livingston, J. D.; Murphy, W. M.; Miller, R. M.; Ayars, E. J.

2005-12-01

Metal sulfate minerals were collected at four surface water drainage sites during September and October of 2004 in the Shasta Mining District, southern Klamath Mountains, Shasta County, California and analyzed by X-ray fluorescence, atomic absorption spectroscopy, and X-ray diffraction to determine elements present, quantities of Fe, Cu, and Zn, and mineralogy. The Shasta Mining District produced major quantities of Cu, Zn, and pyrite (S) with minor amounts of Au, Ag, and Fe from massive sulfide bodies (Kinkel et al., 1956). Three study sites are located on Iron Mountain and one study site is at Bully Hill. Although mining occurred during a period of just over 100 years, it is estimated that acid mine drainage (AMD) will continue from Iron Mountain for over 3,200 years (Nordstrom and Alpers, 1998). AMD at the study sites produces blooms of metal sulfates during California's Mediterranean climate summer. The minerals readily dissolve in the "first flush" of seasonal rain creating runoff water of low pH with high amounts of dissolved metals (Bayless and Olyphant, 1993; Jambor et al., 2000). Data were examined for mineralogical changes in time and space and for zoning of minerals on a scale of centimeters. Sulfate mineral samples are complex with some samples composed of over a dozen different minerals. Site 1 is located on Spring Creek downstream from the Iron Mountain superfund remediation site, so levels of Fe, Cu, and Zn in the sulfates at this site are lower than at the other sites. Two site 1 samples from the same location taken a month apart show Ca, Fe, Cu, Sr, Y, and Sn, and the first sample also has detectable Br. The metal sulfates identified from the first visit are celestine, cesanite, chessexite, hectorfloresite, and ungemachite, and the mineralogy of the second visit is bilinite, epsomite, millosevichite, and anhydrite. The Fe bearing sulfate mineral during the first visit is ungemachite, but bilinite was the Fe bearing mineral at the time of the second visit. Analyses indicate a dynamic evolution of sulfate minerals at individual locations over time, mineralogical and chemical differences among individual locations at a site, and mineralogical zonations in individual samples.

Structural and functional responses of periphyton and macroinvertebrate communities to ferric Fe, Cu, and Zn in stream mesocosms.

PubMed

Cadmus, Pete; Guasch, Helena; Herdrich, Adam T; Bonet, Berta; Urrea, Gemma; Clements, William H

2018-05-01

Two mesocosm experiments were conducted to examine effects of ferric iron (Fe) and mixtures of ferric Fe with aqueous metals (Cu, Zn) on stream benthic communities. Naturally colonized benthic communities were exposed to a gradient of ferric Fe (0, 0.4, 1.0, 2.5, 6.2, and 15.6 mg/L) that bracketed the current US Environmental Protection Agency water quality criterion value (1.0 mg/L). After 10 d of exposure to ferric Fe, total macroinvertebrate abundance, number of taxa, and abundance of all major macroinvertebrate groups (Ephemeroptera, Plecoptera, Trichoptera, and Diptera) were significantly reduced. Heptageniid mayflies and chironomids were especially sensitive to Fe oxide deposition and were significantly reduced at 0.4 and 1.0 mg/L total Fe, respectively. In a second mesocosm experiment, periphyton and macroinvertebrate communities were exposed to ferric Fe (0.60 mg/L) with or without aqueous Cu and Zn at 2 treatment levels: low (0.01 mg/L Cu + 0.1 mg/L Zn) and high (0.05 mg/L Cu + 0.5 mg/L Zn). In contrast to previous research, we observed no evidence of a protective effect of Fe on toxicity of metals. Growth rates and protein content of periphyton were significantly reduced by both ferric Fe and aqueous metals, whereas abundance of heptageniid mayflies (Cinygmula) and whole community metabolism were significantly reduced by ferric Fe alone. We hypothesize that Fe oxides inhibited algal growth and enhanced metal accumulation, leading to a reduction in the quantity and quality of food resources for grazers. Mesocosm experiments conducted using natural benthic communities provide a unique opportunity to quantify the relative importance of indirect physical effects and to develop a better understanding of the relationship between basal food resources and consumers in natural stream ecosystems. Environ Toxicol Chem 2018;37:1320-1329. © 2017 SETAC. © 2017 SETAC.

The association between content of the elements S, Cl, K, Fe, Cu, Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis.

PubMed

Laursen, Jens; Milman, Nils; Pind, Niels; Pedersen, Henrik; Mulvad, Gert

2014-01-01

Meta-analysis of previous studies evaluating associations between content of elements sulphur (S), chlorine (Cl), potassium (K), iron (Fe), copper (Cu), zinc (Zn) and bromine (Br) in normal and cirrhotic autopsy liver tissue samples. Normal liver samples from 45 Greenlandic Inuit, median age 60 years and from 71 Danes, median age 61 years. Cirrhotic liver samples from 27 Danes, median age 71 years. Element content was measured using X-ray fluorescence spectrometry. Dual hierarchical clustering analysis, creating a dual dendrogram, one clustering element contents according to calculated similarities, one clustering elements according to correlation coefficients between the element contents, both using Euclidian distance and Ward Procedure. One dendrogram separated subjects in 7 clusters showing no differences in ethnicity, gender or age. The analysis discriminated between elements in normal and cirrhotic livers. The other dendrogram clustered elements in four clusters: sulphur and chlorine; copper and bromine; potassium and zinc; iron. There were significant correlations between the elements in normal liver samples: S was associated with Cl, K, Br and Zn; Cl with S and Br; K with S, Br and Zn; Cu with Br. Zn with S and K. Br with S, Cl, K and Cu. Fe did not show significant associations with any other element. In contrast to simple statistical methods, which analyses content of elements separately one by one, dual hierarchical clustering analysis incorporates all elements at the same time and can be used to examine the linkage and interplay between multiple elements in tissue samples. Copyright © 2013 Elsevier GmbH. All rights reserved.

Iron oxide nanozyme catalyzed synthesis of fluorescent polydopamine for light-up Zn2+ detection

NASA Astrophysics Data System (ADS)

Liu, Biwu; Han, Xiao; Liu, Juewen

2016-07-01

Fluorescent polydopamine (FPD) is an interesting material with excellent biocompatibility. However, its preparation is currently a lengthy and potentially dangerous process. We herein employ magnetic iron oxide (Fe3O4) nanoparticles as a peroxidase-mimicking nanozyme to produce FPD under mild conditions. Different from previous protocols using multiple steps with up to 6% (~2 M) H2O2, this preparation takes place in a single step with just 5 mM H2O2 at room temperature. The oxidized product shows excitation-wavelength-dependent emission peaks, similar to previous reports. The reaction kinetics, pH, temperature, and ionic strength are individually optimized. Among a diverse range of other nanomaterials tested, including Fe2O3, CeO2, CoO, Co3O4, NiO, TiO2, gold nanoparticles, and graphene oxide, Fe2O3 and graphene oxide yielded relatively weak emission, while the rest of the materials failed to produce FPD. The Fe3O4 nanoparticles retained ~90% catalytic activity even after ten cycles of synthesis. Finally, Zn2+ can enhance the fluorescence of FPD under 360 nm excitation but not under 480 nm excitation, leading to a sensitive light-up sensor with a detection limit of 60 nM Zn2+. Therefore, this work has demonstrated not only a novel use of nanozymes, but also an interesting application of FPD.Fluorescent polydopamine (FPD) is an interesting material with excellent biocompatibility. However, its preparation is currently a lengthy and potentially dangerous process. We herein employ magnetic iron oxide (Fe3O4) nanoparticles as a peroxidase-mimicking nanozyme to produce FPD under mild conditions. Different from previous protocols using multiple steps with up to 6% (~2 M) H2O2, this preparation takes place in a single step with just 5 mM H2O2 at room temperature. The oxidized product shows excitation-wavelength-dependent emission peaks, similar to previous reports. The reaction kinetics, pH, temperature, and ionic strength are individually optimized. Among a diverse range of other nanomaterials tested, including Fe2O3, CeO2, CoO, Co3O4, NiO, TiO2, gold nanoparticles, and graphene oxide, Fe2O3 and graphene oxide yielded relatively weak emission, while the rest of the materials failed to produce FPD. The Fe3O4 nanoparticles retained ~90% catalytic activity even after ten cycles of synthesis. Finally, Zn2+ can enhance the fluorescence of FPD under 360 nm excitation but not under 480 nm excitation, leading to a sensitive light-up sensor with a detection limit of 60 nM Zn2+. Therefore, this work has demonstrated not only a novel use of nanozymes, but also an interesting application of FPD. Electronic supplementary information (ESI) available: Methods, TEM, ζ-potential, and original fluorescence spectra. See DOI: 10.1039/c6nr02584f

Bioavailability of Lead in Small Arms Range Soils

DTIC Science & Technology

2007-09-01

minerals, and may also exist inside particles of inert matrix such as rock or slag of variable size, shape, and association; these chemical and...Abbreviations: Fe=iron, Pb=lead, Cu=copper, Ti=titanium, Zn= zinc , Sb=antimony, Rb=rubidium, Zr=zirconium, As=arsenic. Values are mean of three...20 30 40 50 60 70 80 FeOOH Cerussite Organic Phosphate PbMO PbAsO MnOOH Anglesite PbOOH PbCl4 Slag FeSO4 PbO Frequency of Occurrence Relative Pb

Genome Wide Identification of Orthologous ZIP Genes Associated with Zinc and Iron Translocation in Setaria italica.

PubMed

Alagarasan, Ganesh; Dubey, Mahima; Aswathy, Kumar S; Chandel, Girish

2017-01-01

Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe) and or zinc (Zn). These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica . NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.

Assessment of heavy metal accumulation in macrophyte, agricultural soil, and crop plants adjacent to discharge zone of sponge iron factory

NASA Astrophysics Data System (ADS)

Gupta, S.; Nayek, S.; Saha, R. N.; Satpati, S.

2008-08-01

The present study deals with the characterization of effluent released from sponge iron industries and distribution of heavy metals in soil and macrophytes near to effluent discharge channel. Apart from this, accumulation of heavy metals in nearby soil and vegetation system irrigated with effluent-contaminated water is also the subject of this study. Physico-chemical analysis of effluent reveals that the concentration of total suspended solids (TSS), total hardness (TH), iron (Fe2+), and oil and grease are greater than the IS (1981) norms for discharge of water into inland water body. The soil along the sides of the effluent channel also shows higher concentration of heavy metals than the background soil. The enrichment of the heavy metals are in the order of Chromium (Cr) > Iron (Fe) > Manganese (Mn) > Zinc (Zn) > Copper (Cu) > Cadmium (Cd). Macrophytes growing along the sides of the effluent channel also show significant accumulation of heavy metals almost in the same order as accumulated in soil. Higher uptake of heavy metals by these varieties reveals that these species can be used for future phytoremediation. The effluent as well as contaminated water is extensively used for irrigation for growing vegetables like tomato ( Lycopersicon esculatum) in the surrounding areas. Heavy metal accumulation in this agricultural soil are in the sequence of Cr > Fe > Mn > Zn > Cu > Cd. More or less similar type of accumulation pattern are also found in tomato plants except Fe and Zn exceeding Cr and Mn. Transfer Factor of heavy metals from soil to tomato plants (TFS) shows average value of <1, suggesting less uptake of heavy metals from soil. Among the plant parts studied, fruit shows least accumulation. Although tomato plants show some phenotypic changes, the survival of tomato plants as well as least accumulation of metals in fruit reveals their tolerance to heavy metals. Therefore it may be suggested that this plant can be grown successfully in the heavy metal contaminated soil. Further research work on in situ toxicity test will be necessary in order to identify the most resistive variety on this particular type of contaminated site.

Tracing fluid transfer across subduction zones using iron and zinc stable isotopes

NASA Astrophysics Data System (ADS)

Williams, H. M.; Debret, B.; Pons, M. L.; Bouilhol, P.

2016-12-01

In subduction zones, serpentinite devolatilization within the downgoing slab and the fluids released play a fundamental role in volatile transfer as well as the redox evolution of the sub-arc mantle. Constraining subduction-related serpentinite devolatilisation is essential in order to better understand of the nature and composition of slab-derived fluids and fluid/rock interactions. Fe and Zn stable isotopes can trace fluid composition and speciation as isotope partitioning is driven by changes in oxidation state, coordination, and bonding environment. In the case of serpentinite devolatilisation, Fe isotope fractionation should reflect changes in Fe redox state and the formation of Fe-Cl- and SO42- complexes (Hill et al., GCA 2010); Zn isotope fractionation should be sensitive to complexation with CO32-, HS- and SO42- anions (Fujii et al., GCA 2011). We targeted samples from Western Alps ophiolite complexes, interpreted as remnants of serpentinized oceanic lithosphere metamorphosed and devolatilized during subduction (Hattori and Guillot, G3 2007; Debret et al., Chem. Geol. 2013). A striking negative correlation is present between bulk serpentinite Fe isotope composition and Fe3+/Fetot, with the highest grade samples displaying the heaviest Fe isotope compositions and lowest Fe3+/Fetot (Debret et al., Geology, 2016). The same samples also display a corresponding variation in Zn isotopes, with the highest grade samples displaying isotopically light compositions (Pons et al., in revision). The negative correlation between Fe and Zn isotopes and decrease in Fe3+/Fetot can explained by serpentinite sulfide breakdown and the release of fluids enriched in isotopically light Fe and heavy Zn sulphate complexes. The migration of these SOX-bearing fluids from the slab to the slab-mantle interface or mantle wedge has important implications for the redox evolution of the sub-arc mantle and the transport of metals from the subducting slab.

Association mapping unveils favorable alleles for grain iron and zinc concentrations in lentil (Lens culinaris subsp. culinaris)

PubMed Central

Singh, Akanksha; Sharma, Vinay; Dikshit, Harsh Kumar; Aski, Muraleedhar; Kumar, Harish; Thirunavukkarasu, Nepolean; Patil, Basavanagouda S.; Kumar, Shiv; Sarker, Ashutosh

2017-01-01

Lentil is a major cool-season grain legume grown in South Asia, West Asia, and North Africa. Populations in developing countries of these regions have micronutrient deficiencies; therefore, breeding programs should focus more on improving the micronutrient content of food. In the present study, a set of 96 diverse germplasm lines were evaluated at three different locations in India to examine the variation in iron (Fe) and zinc (Zn) concentration and identify simple sequence repeat (SSR) markers that associate with the genetic variation. The genetic variation among genotypes of the association mapping (AM) panel was characterized using a genetic distance-based and a general model-based clustering method. The model-based analysis identified six subpopulations, which satisfactorily explained the genetic structure of the AM panel. AM analysis identified three SSRs (PBALC 13, PBALC 206, and GLLC 563) associated with grain Fe concentration explaining 9% to 11% of phenotypic variation and four SSRs (PBALC 353, SSR 317–1, PLC 62, and PBALC 217) were associated with grain Zn concentration explaining 14%, to 21% of phenotypic variation. These identified SSRs exhibited consistent performance across locations. These candidate SSRs can be used in marker-assisted genetic improvement for developing Fe and Zn fortified lentil varieties. Favorable alleles and promising genotypes identified in this study can be utilized for lentil biofortification. PMID:29161321

Iron, zinc and calcium dialyzability from extruded product based on whole grain amaranth (Amaranthus caudatus and Amaranthus cruentus) and amaranth/Zea mays blends.

PubMed

Galan, María Gimena; Drago, Silvina Rosa; Armada, Margarita; José, Rolando González

2013-06-01

Amaranth is a Native American grain appreciated for its high nutritional properties including high mineral content. The aim of this study was to evaluate the availability of Fe, Zn and Ca from extruded products made with two varieties of amaranth and their mixtures with maize at two levels of replacement. Mineral availability was estimated using dialyzability method. The contents of Fe (64.0-84.0 mg/kg), Ca (1977.5-2348.8 mg/kg) and Zn (30.0-32.1 mg/kg) were higher in amaranth than in maize products (6.2, 19.1, 9.7 mg/kg, respectively). Mineral availability was in the range of (2.0-3.6%), (3.3-11.1%) and (1.6-11.4%) for Fe, Ca and Zn, respectively. Extruded amaranth and amaranth/maize products provide higher amount of Fe and Ca than extruded maize. Extruded amaranth products and amaranth addition to maize could be an interesting way to increase nutritional value of extruded products.

Effect of nano zero-valent iron application on As, Cd, Pb, and Zn availability in the rhizosphere of metal(loid) contaminated soils.

PubMed

Vítková, Martina; Puschenreiter, Markus; Komárek, Michael

2018-06-01

Characterisation of geochemical transformations and processes in soils with special focus on the rhizosphere is crucial for assessing metal(loid) bioavailability to plants during in situ immobilisation and phytostabilisation. In this study, the effects of nano zero-valent iron (nZVI) were investigated in terms of the immobilisation of As, Zn, Pb and Cd in two soil types and their potential uptake by plants using rhizobox experiments. Such system allowed monitoring the behaviour of trace elements in rooted and bulk soil compartments separately. Sunflower (Helianthus annuus L.) and ryegrass (Lolium perenne L.) were tested for As-rich (15.9 g As kg -1 ) and Zn-rich (4.1 g Zn kg -1 ) soil samples, respectively. The application of nZVI effectively lowered the uptake of all target risk elements into plant tissues. Efficient immobilisation of As was determined in the As-soil without a significant difference between plant and bulk soil compartments. Similarly, a significant decrease was determined for CaCl 2 -available fractions of Zn, Pb and Cd in nZVI-treated Zn-soil. The behaviour of As corresponded to changes in Eh, while Zn and Cd showed to be mainly pH-dependent. However, despite the observed stabilisation effect of nZVI, high amounts of As and Zn still remained available for plants. Furthermore, the accumulation of the target risk elements in roots and the overall effect of nZVI transformations in the rhizosphere were verified and visualised by SEM/EDS. The following immobilising mechanisms were suggested: (i) sorption onto both existing and newly formed Fe (hydr)oxides, (ii) formation of secondary Fe-As phases, and (iii) sorption onto Mn (hydr)oxides. Copyright © 2018 Elsevier Ltd. All rights reserved.

Iron and manganese oxide mineralization in the Pacific

USGS Publications Warehouse

Hein, J.R.; Koschinsky, A.; Halbach, P.; Manheim, F.T.; Bau, M.; Kang, J.-K.; Lubick, N.

1997-01-01

Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic and tectonic environments in the ocean basins and form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) precipitation from hydrothermal fluids, (3) precipitation from sediment pore waters that have been modified from bottom water compositions by diagenetic reactions in the sediment column and (4) replacement of rocks and sediment. Iron and manganese deposits occur in five forms: nodules, crusts, cements, mounds and sediment-hosted stratabound layers. Seafloor oxides show a wide range of compositions from nearly pure iron to nearly pure manganese end members. Fe/Mn ratios vary from about 24 000 (up to 58% elemental Fe) for hydrothermal seamount ironstones to about 0.001 (up to 52% Mn) for hydrothermal stratabound manganese oxides from active volcanic arcs. Hydrogenetic Fe-Mn crusts that occur on most seamounts in the ocean basins have a mean Fe/Mn ratio of 0.7 for open-ocean seamount crusts and 1.2 for continental margin seamount crusts. Fe-Mn nodules of potential economic interest from the Clarion-Clipperton Zone have a mean Fe/Mn ratio of 0.3, whereas the mean ratio for nodules from elsewhere in the Pacific is about 0.7. Crusts are enriched in Co, Ni and Pt and nodules in Cu and Ni, and both have significant concentrations of Pb, Zn, Ba, Mo, V and other elements. In contrast, hydrothermal deposits commonly contain only minor trace metal contents, although there are many exceptions, for example, with Ni contents up to 0.66%, Cr to 1.2%, and Zn to 1.4%. Chondrite-normalized REE patterns generally show a positive Ce anomaly and abundant ΣREEs for hydrogenetic and mixed hydrogenetic-diagenetic deposits, whereas the Ce anomaly is negative for hydrothermal deposits and ΣREE contents are low. However, the Ce anomaly in crusts may vary from strongly positive in East Pacific crusts to slightly negative in West Pacific crusts, which may reflect the redox conditions of seawater. The concentration of elements in hydrogenetic Fe-Mn crusts depends on a wide variety of water column and crust surface characteristics, whereas concentration of elements in hydrothermal oxide deposits depends of the intensity of leaching, rock types leached, and precipitation of sulphides at depth in the hydrothermal system.

Dietary exposure to toxic and essential trace elements by consumption of wild and farmed carp (Cyprinus carpio) and Caspian kutum (Rutilus frisii kutum) in Iran.

PubMed

Heshmati, Ali; Karami-Momtaz, Javad; Nili-Ahmadabadi, Amir; Ghadimi, Sabah

2017-04-01

This study was conducted to determine and compare the concentrations of mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), nickel (Ni), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), cobalt (Co), and selenium (Se) in the muscle of wild and farmed carp (Cyprinus carpio) and wild and farmed Caspian kutum (Rutilus frisii kutum) collected from south-western Caspian Sea areas of Iran between December 2014 and March 2015. In addition, risk assessment of consumers to exposure to metals through fish consumption was estimated. In all the samples, the arsenic concentration was lower than the detection limit. The Pb, Cd, Hg and Mn concentrations were significantly higher in the wild fish samples compared to the farmed fish samples. There was no significant difference in the Fe, Zn, Cu, Co, Ni and Se concentrations of the wild and farmed carp and the wild and farmed Caspian kutum. Iron displayed the highest concentration of all the analysed metals in both the wild and farmed fish, followed by Zn and Cu. The highest Hg, Cd, Pb, Ni, Fe, Zn, Cu, Mn, Co and Se concentrations were 0.056, 0.011, 0.065, 0.120, 4.151, 3.792, 2.948, 2.690, 0.037 and 0.162 μg g -1 , respectively. The estimated daily intake of all metals was acceptable, and the hazard quotient values showed that consumption of the analysed fish posed no health risk to consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of biostimulated redox processes on metal dynamics in an iron-rich creek soil of a former uranium mining area.

PubMed

Burkhardt, Eva-Maria; Akob, Denise M; Bischoff, Sebastian; Sitte, Jana; Kostka, Joel E; Banerjee, Dipanjan; Scheinost, Andreas C; Küsel, Kirsten

2010-01-01

Understanding the dynamics of metals and radionuclides in soil environments is necessary for evaluating risks to pristine sites. An iron-rich creek soil of a former uranium-mining district (Ronneburg, Germany) showed high porewater concentrations of heavy metals and radionuclides. Thus, this study aims to (i) evaluate metal dynamics during terminal electron accepting processes (TEAPs) and (ii) characterize active microbial populations in biostimulated soil microcosms using a stable isotope probing (SIP) approach. In biostimulated soil slurries, concentrations of soluble Co, Ni, Zn, As, and unexpectedly U increased during Fe(III)-reduction. This suggests that there was a release of sorbed metals and As during reductive dissolution of Fe(III)-oxides. Subsequent sulfate-reduction was concurrent with a decrease of U, Co, Ni, and Zn concentrations. The relative contribution of U(IV) in the solid phase changed from 18.5 to 88.7% after incubation. The active Fe(III)-reducing population was dominated by delta-Proteobacteria (Geobacter) in (13)C-ethanol amended microcosms. A more diverse community was present in (13)C-lactate amended microcosms including taxa related to Acidobacteria, Firmicutes, delta-Proteobacteria, and beta-Proteobacteria. Our results suggested that biostimulated Fe(III)-reducing communities facilitated the release of metals including U to groundwater which is in contrast to other studies.

Distribution of potentially toxic elements (PTEs) in tailings, soils, and plants around Gol-E-Gohar iron mine, a case study in Iran

PubMed Central

Soltani, Naghmeh; Keshavarzi, Behnam; Moore, Farid; Sorooshian, Armin; Ahmadi, Mohamad Reza

2017-01-01

This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg−1 for As (with a mean of 25.39 mg kg−1 for tailings), 7.9 and 261.5 mg kg−1 (mean 189.83 mg kg−1 for tailings) for Co, 17.7 and 885.03 mg kg−1 (mean 472.77 mg kg−1 for tailings) for Cu, 12,500 and 400,000 mg kg−1 (mean 120,642.86 mg kg−1 for tailings) for Fe, and 28.1 and 278.1 mg kg−1 (mean 150.29 mg kg−1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition. PMID:28620857

Studies on the bioavailability of zinc in humans: intestinal interaction of tin and zinc.

PubMed

Solomons, N W; Marchini, J S; Duarte-Favaro, R M; Vannuchi, H; Dutra de Oliveira, J E

1983-04-01

Mineral/mineral interactions at the intestinal level are important in animal nutrition and toxicology, but only limited understanding of their extent or importance in humans has been developed. An inhibitory interaction of dietary tin on zinc retention has been recently described from human metabolic studies. We have explored the tin/zinc interaction using the change-in-plasma-zinc-concentration method with a standard dosage of 12.5 mg of zinc as zinc sulfate in 100 ml of Coca-Cola. Sn/Zn ratios of 2:1, 4:1, and 8:1, constituted by addition of 25, 50, and 100 mg of tin as stannous chloride, had no significant overall effect on zinc uptake. The 100-mg dose of tin produced noxious gastrointestinal symptoms. Addition of iron as ferrous sulfate to form ratios of Sn/Fe/Zn of 1:1:1 and 2:2:1 with the standard zinc solution and the appropriate doses of tin produced a reduction of zinc absorption not dissimilar from that seen previously with zinc and iron alone, and addition of picolinic acid did not influence the uptake of zinc from the solution with the 2:2:1 Sn/Fe/Zn ratio.

Fe (III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of schiff bases based-on glycine and phenylalanine: Synthesis, magnetic/thermal properties and antimicrobial activity

NASA Astrophysics Data System (ADS)

Sevgi, Fatih; Bagkesici, Ugur; Kursunlu, Ahmed Nuri; Guler, Ersin

2018-02-01

Zinc (II), copper (II), nickel (II), cobalt (II) and iron (III) complexes of Schiff bases (LG, LP) derived from 2-hydroxynaphthaldehyde with glycine and phenylalanine were reported and characterized by 1H NMR, 13C NMR, elemental analyses, melting point, FT-IR, magnetic susceptibility and thermal analyses (TGA). TGA data show that iron and cobalt include to the coordinated water and metal:ligand ratio is 1:2 while the complex stoichiometry for Ni (II), Cu (II) and Zn (II) complexes is 1:1. As expected, Ni (II) and Zn (II) complexes are diamagnetic; Cu (II), Co (II) and Fe (III) complexes are paramagnetic character due to a strong ligand of LG and LP. The LG, LP and their metal complexes were screened for their antimicrobial activities against five Gram-positive (Staphylococcus aureus, Methicillin resistant Staphylococcus aureus (MRSA), Bacillus cereus, Streptococcus mutans and Enterococcus faecalis) and three Gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and one fungi (Candida albicans) by using broth microdilution techniques. The activity data show that ligands and their metal complexes exhibited moderate to good activity against Gram-positive bacteria and fungi.

A baseline study on the concentration of trace elements in the surface sediments off Southwest coast of Tamil Nadu, India.

PubMed

Godson, Prince S; Magesh, N S; Peter, T Simon; Chandrasekar, N; Krishnakumar, S; Vincent, Salom Gnana Thanga

2018-01-01

Forty two surface sediment samples were collected in order to document baseline elemental concentration along the Southwest coast of Tamil Nadu, India. The elements detected were Manganese (Mn), Zinc (Zn), Iron (Fe), Copper (Cu), Nickel (Ni) and Lead (Pb). The concentration of Fe and Mn was primarily controlled by the riverine input. The source of Pb and Zn is attributed to leaded petrol and anti-biofouling paints. The calculated index (EF, Igeo and CF) suggests that the sediments of the study area are significantly enriched with all elements except Pb. The contamination factor showed the order of Mn>Zn>Fe>Cu>Ni>Pb. The sediment pollution index (SPI) revealed that the sediments belonged to low polluted to dangerous category. The correlation matrix and dendrogram showed that the elemental distribution was chiefly controlled by riverine input as well as anthropogenic activity in the coast. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pb2+ and Zn2+ adsorption by a natural aluminum- and iron-bearing surface coating on an aquifer sand

USGS Publications Warehouse

Coston, J.A.; Fuller, C.C.; Davis, J.A.

1995-01-01

Pb2+ and Zn2+ adsorption was studied in batch experiments with material collected from a shallow, unconfined aquifer of glacial outwash sand and gravel in Falmouth, Massachusetts, USA. The aquifer solids contain primarily quartz with minor amounts of alkali feldspars and ferromagnetic minerals. Pb2+ and Zn2+ adsorption experiments with various grain size and mineral fractions of the aquifer solids showed that: 1) Zn2+ adsorption was independent of grain size, but Pb2+ was preferentially adsorbed by the <64 ??m size fraction and 2) Pb2+ adsorption decreased after removal of the paramagnetic, Fe-bearing mineral fraction, but Zn2+ adsorption was unaffected. Pb2+ and Zn2+ adsorption on mineral separates from the aquifer material compared with metal adsorption on a purified quartz powder indicated that adsorption of both metal ions was dominated by coatings on the quartz fraction of the sediment. Characterization of the coatings by AES, SEM-EDS, and TOF-SIMS demonstrated that the natural quartz grains were extensively coated with Al- and Fe-bearing minerals of variable composition. -from Authors

The cycling of iron, zinc and cadmium in the North East Pacific Ocean - Insights from stable isotopes

NASA Astrophysics Data System (ADS)

Conway, Tim M.; John, Seth G.

2015-09-01

Dissolved stable isotope ratios of the transition metals provide useful information, both for understanding the cycling of these bioactive trace elements through the oceans, and tracing their marine sources and sinks. Here, we present seawater dissolved Fe, Zn and Cd concentration and stable isotope ratio (δ56Fe, δ66Zn, and δ114Cd) profiles from two stations in the Pacific Ocean, the SAFe Station (30°N 140°W) in the subtropical North East Pacific from the GEOTRACES IC2 cruise, and the marginal San Pedro Basin (33.8°N 118.4°W) within the South California Bight. These data represent, to our knowledge, the first full-water column profiles for δ66Zn and δ56Fe from the open-ocean North Pacific, and the first observations of dissolved δ66Zn and δ114Cd in a low-oxygen marginal basin. At the SAFe station, δ56Fe is isotopically lighter throughout the water column (-0.6 to +0.1‰, relative to IRRM-014) compared to the North Atlantic, suggesting significant differences in Fe sources or Fe cycling between these two ocean basins. A broad minimum in δ56Fe associated with the North Pacific oxygen minimum zone (OMZ; <75 μmol kg-1 dissolved oxygen; ∼550-2000 m depth) is consistent with reductive sediments along the California margin being an important source of dissolved Fe to the North Pacific. Other processes which may influence δ56Fe at SAFe include biological cycling in the upper ocean, and input of Fe from hydrothermal vents and oxic sediments below the OMZ. Zn and Cd concentration profiles at both stations broadly match the distribution of the macronutrients silicate and phosphate, respectively. At SAFe, δ114Cd increases towards the surface, reflecting the biological preference for assimilation of lighter Cd isotopes, while negative Cd∗ (-0.12) associated with low oxygen waters supports the recently proposed hypothesis of water-column CdS precipitation. In contrast to δ114Cd, δ66Zn at SAFe decreases towards the surface ocean, perhaps due to scavenging of isotopically heavy Zn, while at intermediate depths δ66Zn provides further evidence of a mid-depth dissolved δ66Zn maximum. We suggest this may be a global feature of Zn biogeochemistry related to either regeneration of heavy adsorbed Zn, or to ZnS formation and removal within the water column. Data from San Pedro shows that anoxic sediments can be a source of isotopically light Zn to the water column (δ66Zn of ∼-0.3‰ relative to JMC Lyon), though evidence of this signal is not observed being transported to SAFe. Within North Pacific Intermediate Water at SAFe (NPIW; ∼500 m) elevated Cd∗ and Zn∗ and a focused minimum in δ56Fe suggest possible transport of Fe, Zn, and Cd over thousands of km from subpolar waters, meaning that NPIW may have a strong influence on the subsurface distribution of trace metals throughout the North Pacific.

Adsorption of tetracycline on Fe (hydr)oxides: effects of pH and metal cation (Cu2+, Zn2+ and Al3+) addition in various molar ratios

PubMed Central

Hsu, Liang-Ching; Liu, Yu-Ting; Syu, Chien-Hui; Huang, Mei-Hsia; Teah, Heng Yi

2018-01-01

Iron (Fe) (hydr)oxides control the mobility and bioavailability of tetracycline (TC) in waters and soils. Adsorption of TC on Fe (hydr)oxides is greatly affected by polyvalent metals; however, impacts of molar metal/TC ratios on TC adsorptive behaviours on Fe (hydr)oxides remain unclear. Results showed that maximum TC adsorption on ferrihydrite and goethite occurred at pH 5–6. Such TC adsorption was generally promoted by the addition of Cu2+, Zn2+ and Al3+. The greatest increase in TC adsorption was found in the system with molar Cu/TC ratio of 3 due to the formation of Fe hydr(oxide)–Cu–TC ternary complexes. Functional groups on TC that were responsible for the complexation with Cu2+shifted from phenolic diketone groups at Cu/TC molar ratio < 1 to amide groups at Cu/TC molar ratio ≥ 1. For the addition of Al3+, the complexation only took place with phenolic diketone groups, resulting in the enhanced TC adsorption at a molar Al/TC ratio of 1. However, TC adsorption decreased for Al/TC molar ratio > 1 as excess Al3+ led to the competitive adsorption with Al/TC complexes. For the Zn2+ addition, no significant correlation was found between TC adsorption capacity and molar Zn/TC ratios. PMID:29657795

Power scaling of ultrafast laser inscribed waveguide lasers in chromium and iron doped zinc selenide.

PubMed

McDaniel, Sean A; Lancaster, Adam; Evans, Jonathan W; Kar, Ajoy K; Cook, Gary

2016-02-22

We report demonstration of Watt level waveguide lasers fabricated using Ultrafast Laser Inscription (ULI). The waveguides were fabricated in bulk chromium and iron doped zinc selenide crystals with a chirped pulse Yb fiber laser. The depressed cladding structure in Fe:ZnSe produced output powers of 1 W with a threshold of 50 mW and a slope efficiency of 58%, while a similar structure produced 5.1 W of output in Cr:ZnSe with a laser threshold of 350 mW and a slope efficiency of 41%. These results represent the current state-of-the-art for ULI waveguides in zinc based chalcogenides.

Nutritional improvement of corn pasta-like product with broad bean (Vicia faba) and quinoa (Chenopodium quinoa).

PubMed

Giménez, M A; Drago, S R; Bassett, M N; Lobo, M O; Sammán, N C

2016-05-15

In this study, the nutritional quality of pasta-like product (spaghetti-type), made with corn (Zea mays) flour enriched with 30% broad bean (Vicia faba) flour and 20% of quinoa (Chenopodium quinoa) flour, was determined. Proximate chemical composition and iron, zinc and dietary fiber were determined. A biological assay was performed to assess the protein value using net protein utilization (NPU), true digestibility (TD) and protein digestibility-corrected amino acid score (PDCAAS). Iron and zinc availability were estimated by measuring dialyzable mineral fraction (%Da) resulting from in vitro gastrointestinal digestion. Nutritionally improved, gluten-free spaghetti (NIS) showed significantly increased NPU and decreased TD compared with a non-enriched control sample. One NIS-portion supplied 10-20% of recommended fiber daily intake. Addition of quinoa flour had a positive effect on the FeDa% as did broad bean flour on ZnDa%. EDTA increased Fe- and ZnDa% in all NIS-products, but it also impaired sensorial quality. Copyright © 2016. Published by Elsevier Ltd.

Photographic Processing Interpretation Facility Wastewater Conceptual Treatment Design.

DTIC Science & Technology

1983-03-01

Total Chromium (Cr) - - - ɘ.05 - Copper (Cu) - - - ɘ.05 - Iron (Fe) - - - - - Manganese (Mn) - - - ɘ.03 - Mercury (Hg) - - - ɘ.004 - Potassium (K...8.3 - Silver (Ag) 2.2 7.0 17 0.15 2.2 Sodium (Na) - - - 8.2 - Zinc (Zn) - - - 0.12 - Biochemical Oxygen " Demand (BOD_) - - - 40 - Sulfate (SO...nonconventional pollutants include boron, dissolved sol i halides, iron, ammonia, nitrogen, phenols, sulfate and TOC. ,P,, 99 percent of the 11,000

Evaluation of Trace Elements and Their Relationship with Growth and Development of Young Children.

PubMed

Cao, Jia; Gao, Zhenyan; Yan, Jin; Li, Minming; Su, Jia; Xu, Jian; Yan, Chong-Huai

2016-06-01

This study was conducted to assess the levels of trace elements and their relationship with growth and development of children in Shanghai, China, to offer scientific evidence for supplementing trace elements in children. A stratified, clustered, random sampling method was used in the study. Blood samples were taken from 2141 Shanghai children from 0 to 6.0 years old, and the concentrations of zinc (Zn), calcium (Ca), iron (Fe), copper (Cu), and magnesium (Mg) were measured using inductively coupled plasma mass spectrometry (ICP-MS). Nutritional status was determined and Z-scores of anthropometric parameters, such as height for age (HFA), weight for age (WFA), and body mass index (BMI) were calculated, indicated by HAZ, WAZ, and BMIZ, respectively. The overall median blood levels of Zn, Ca, Fe, Cu, and Mg were 8.83, 79.02, 9.49, 1.04, and 15.45 mg/L, respectively. Fe, Cu, and Mg increased with age and Zn, Fe, and Cu differed by sex. HAZ and WAZ were positively correlated with Zn (r (2) = 0.072 and 0.053, respectively; P < 0.05). Trace elements were significantly related to children's growth and development. Dietary supplementation and screening of nutritional states are potential solutions to improve children's growth and development.

Chromate reduction and heavy metal fixation in soil

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

Schwitzgebel, K.

In situ reduction of chromates and the fixation of the metals Cr, Pb, Zn, Cu, Cd and Ni in soil was investigated using Fe II and soluble silica. Fe II fulfills two functions. It reduces chromates (CrVI) at soil pH to CrIII and the reaction products, Fe(OH)[sub 3] and Cr(OH)[sub 3], coprecipitate/adsorb heavy metals. In the absence of CrVI iron is added as FeIII. Destabilized silica also fulfills two functions. It reacts with the metal and metal hydroxides and reduces the soil permeability. The leaching rate (mg/m[sup 2]s) of a metal is the product of leachate flow rate ([ell]/M[sup 2]s)more » and the leachate concentration (mg/[ell]). The leachate flow rate is directly proportional to the hydraulic coefficient (Darcy's Law). Treatment with destabilized silica reduces the hydraulic coefficient of virgin soil (K[sub h] = 10[sup [minus]2]...10[sup [minus]4]) to K[sub h]=10[sup [minus]7] (cm/s) resulting in a flow rate reduction of 3--5 orders of magnitude. Iron plus silica treatment results in a leachate concentration reduction of up to 2 orders of magnitude (Cr:95--99%;Pb:99%;Zn 95--99%; Cd:93--99%; Ni:75--94%). Combined effect of flow rate reduction and leachate concentration reduction results in a potential leaching rate reduction of five to seven orders of magnitude. Iron-silica treatment may be developed into an efficient containment technology, provided the silica gel integrity does not change with time.« less

Chromate reduction and heavy metal fixation in soil. Final report

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

Schwitzgebel, K.

In situ reduction of chromates and the fixation of the metals Cr, Pb, Zn, Cu, Cd and Ni in soil was investigated using Fe II and soluble silica. Fe II fulfills two functions. It reduces chromates (CrVI) at soil pH to CrIII and the reaction products, Fe(OH){sub 3} and Cr(OH){sub 3}, coprecipitate/adsorb heavy metals. In the absence of CrVI iron is added as FeIII. Destabilized silica also fulfills two functions. It reacts with the metal and metal hydroxides and reduces the soil permeability. The leaching rate (mg/m{sup 2}s) of a metal is the product of leachate flow rate ({ell}/M{sup 2}s)more » and the leachate concentration (mg/{ell}). The leachate flow rate is directly proportional to the hydraulic coefficient (Darcy`s Law). Treatment with destabilized silica reduces the hydraulic coefficient of virgin soil (K{sub h} = 10{sup {minus}2}...10{sup {minus}4}) to K{sub h}=10{sup {minus}7} (cm/s) resulting in a flow rate reduction of 3--5 orders of magnitude. Iron plus silica treatment results in a leachate concentration reduction of up to 2 orders of magnitude (Cr:95--99%;Pb:99%;Zn 95--99%; Cd:93--99%; Ni:75--94%). Combined effect of flow rate reduction and leachate concentration reduction results in a potential leaching rate reduction of five to seven orders of magnitude. Iron-silica treatment may be developed into an efficient containment technology, provided the silica gel integrity does not change with time.« less

Inclusion of Guava Enhances Non-Heme Iron Bioavailability but Not Fractional Zinc Absorption from a Rice-Based Meal in Adolescents12

PubMed Central

Nair, Krishnapillai Madhavan; Brahmam, Ginnela N.V.; Radhika, Madhari S.; Dripta, Roy Choudhury; Ravinder, Punjal; Balakrishna, Nagalla; Chen, Zhensheng; Hawthorne, Keli M.; Abrams, Steven A.

2013-01-01

Assessing the bioavailability of non-heme iron and zinc is essential for recommending diets that meet the increased growth-related demand for these nutrients. We studied the bioavailability of iron and zinc from a rice-based meal in 16 adolescent boys and girls, 13–15 y of age, from 2 government-run residential schools. Participants were given a standardized rice meal (regular) and the same meal with 100 g of guava fruit (modified) with 57Fe on 2 consecutive days. A single oral dose of 58Fe in orange juice was given at a separate time as a reference dose. Zinc absorption was assessed by using 70Zn, administered intravenously, and 67Zn given orally with meals. The mean hemoglobin concentration was similar in girls (129 ± 7.8 g/L) and boys (126 ± 7.1 g/L). There were no sex differences in the indicators of iron and zinc status except for a higher hepcidin concentration in boys (P < 0.05). The regular and modified meals were similar in total iron (10–13 mg/meal) and zinc (2.7 mg/meal) content. The molar ratio of iron to phytic acid was >1:1, but the modified diet had 20 times greater ascorbic acid content. The absorption of 57Fe from the modified meal, compared with regular meal, was significantly (P < 0.05) greater in both girls (23.9 ± 11.2 vs. 9.7 ± 6.5%) and boys (19.2 ± 8.4 vs. 8.6 ± 4.1%). Fractional zinc absorption was similar between the regular and modified meals in both sexes. Hepcidin was found to be a significant predictor of iron absorption (standardized β = −0.63, P = 0.001, R2 = 0.40) from the reference dose. There was no significant effect of sex on iron and zinc bioavailability from meals. We conclude that simultaneous ingestion of guava fruit with a habitual rice-based meal enhances iron bioavailability in adolescents. PMID:23596161

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

Margrete Meltzer, Helle, E-mail: helle.margrete.meltzer@fhi.no; Lise Brantsaeter, Anne; Borch-Iohnsen, Berit

Low iron (Fe) stores may influence absorption or transport of divalent metals in blood. To obtain more knowledge about such associations, the divalent metal ions cadmium (Cd), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb) and parameters of Fe metabolism (serum ferritin, haemoglobin (Hb) and transferrin) were investigated in 448 healthy, menstruating non-smoking women, age 20-55 years (mean 38 years), participating in the Norwegian HUNT 2 study. The study population was stratified for serum ferritin: 257 were iron-depleted (serum ferritin <12 {mu}g/L) and 84 had iron deficiency anaemia (serum ferritin <12 {mu}g/L and Hb<120 g/L). The lowmore » ferritin group had increased blood concentrations of Mn, Co and Cd but normal concentrations of Cu, Zn and Pb. In multiple regression models, ferritin emerged as the main determinant of Mn, Co and Cd (p<0.001), while no significant associations with Cu, Zn and Pb were found. Adjusted r{sup 2} for the models were 0.28, 0.48 and 0.34, respectively. Strong positive associations between blood concentrations of Mn, Co and Cd were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the six divalent metals studied. Very mild anaemia (110{<=}Hb<120 g/L) did not seem to have any effect independent of low ferritin. Approximately 26% of the women with iron deficiency anaemia had high concentrations of all of Mn, Co and Cd as opposed to 2.3% of iron-replete subjects. The results confirm that low serum ferritin may have an impact on body kinetics of certain divalent metal ions, but not all. Only a fraction of women with low iron status exhibited an increased blood concentration of divalent metals, providing indication of complexities in the body's handling of these metals.« less

High-zinc rice as a breakthrough for high nutritional rice breeding program

NASA Astrophysics Data System (ADS)

Barokah, U.; Susanto, U.; Swamy, M.; Djoar, D. W.; Parjanto

2018-03-01

WHO reported climate change already takes 150,000 casualties annually, due to the emergence of various diseases and malnutrition caused by food shortages and disasters. Rice is the staple food for almost all of Indonesian citizens, therefore Zn biofortification on rice is expected to be effective, efficient, massive, and sustainable to overcome the Zn nutritional deficiency. This study aims to identify rice with high Zn content and yield for further effort in releasing this variety. Ten lines along with two varieties as a comparison (Ciherang and Inpari 5 Merawu) were tested in Plumbon Village, Mojolaban Subdistrict, Sukoharjo Regency during February-May 2017. The experiment was designed in a Randomized Completely Block Design with four replications on a 4 m x 5 m area, with 25 cm x 25 cm plant spacing using seedling transplanting techniques of 21 days old seeds. The results showed that the plant genotypes treated had differences in yield characteristics, heading date, harvest age, panicle number, filled and un-filled grain per panicle, seed set, 1000 grains weight, Zn and Iron (Fe) content in rice grain. B13884-MR-29-1-1 line (30.94 ppm Zn, 15.84 ppm Fe, 4.11 ton/ha yield) and IR 97477- 115-1-CRB-0-SKI-1-SKI-0-2 (29.61 ppm Zn, 13.49 ppm Zn, 4.4 ton/ha yield) are prospective variety to be released. Ciherang had Zn content of 23.04 ppm, 11.93 ppm Fe, and yield of 4.07 t/ha.

HIGH TEMPERATURE INTERACTIONS BETWEEN RESIDUAL OIL ASH AND DISPERSED KAOLINITE POWDERS

EPA Science Inventory

The potential use of sorbents to manage ultrafine ash aerosol emissions from residual oil combustion was investigated using a downfired 82-kW-rated laboratory-scale refractory-lined combustor. The major constituents were vanadium (V), iron (Fe), nickel, (Ni) and zinc (Zn). Of the...

Digestibility and retention of zinc, copper, manganese, iron, calcium, and phosphorus in pigs fed diets containing inorganic or organic minerals.

PubMed

Liu, Y; Ma, Y L; Zhao, J M; Vazquez-Añón, M; Stein, H H

2014-08-01

The objective of this experiment was to measure the apparent total tract digestibility (ATTD) and the retention rate of Zn, Cu, Mn, and Fe in pigs fed either inorganic or organic sources of Zn, Cu, Mn, and Fe. The experimental design was a randomized complete block design with a 2 × 3 factorial arrangement of treatments. There were 2 types of diets (corn grits-based or corn-soybean meal [SBM]-based diets) and 3 micromineral treatments (basal micromineral premix [BMM], inorganic micromineral premix [IMM], and organic micromineral premix [OMM]). The BMM contained no added Zn, Cu, Mn, or Fe; the IMM microminerals were provided as sulfates of Zn, Cu, Mn, and Fe at 40, 50, 20, and 100 mg/kg, respectively. The OMM contained the same levels of the 4 microminerals as IMM, but Zn, Cu, Mn, and Fe in this premix were provided by Zn(2-hydroxy-4-methylthio butanoic acid [HMTBa])2, Cu(HMTBa)2, Mn(HMTBa)2, and FeGly, respectively. Forty-eight barrows (initial BW: 31.1 ± 4.2 kg) were housed individually and allowed ad libitum access to the corn grits diet with BMM for 2 wk. All pigs were then moved to metabolism cages and randomly assigned to 1 of the 6 treatment diets with 8 replicates per diet. Fecal and urine samples were collected for 5 d following a 5-d adaptation period. Compared with corn grits diets, pigs fed corn-SBM diets had greater (P < 0.05) absorption and retention of Zn, Cu, and Mn but less (P < 0.05) ATTD of Zn and Cu. Compared with BMM, supplementation of IMM or OMM increased (P < 0.05) absorption, retention, ATTD, and retention rate of Zn, Cu, Mn, and Fe. Compared with IMM, adding OMM to the corn-SBM diet improved (P < 0.05) the absorption and retention of Cu and Mn and the ATTD of Cu, but these differences were not observed in the corn grits diets (interaction, P < 0.05). In addition, adding OMM to the corn-SBM diet increased (P < 0.05) absorption and retention of Zn and Fe and ATTD of Zn, Mn, and Fe compared with adding IMM to the corn-SBM diet. Supplementation of OMM also increased (P < 0.05) the ATTD and retention rate of P in corn-SBM diets. Results indicate that Zn(HMTBa)2 has greater digestibility and Cu(HMTBa)2 and Mn(HMTBa)2 have greater digestibility and retention rates compared with their inorganic sulfates, if included in a corn-SBM diet. Supplementation of organic microminerals also improves the digestibility of P in a corn-SBM diet.

Trojan Horse for Light-Triggered Bifurcated Production of Singlet Oxygen and Fenton-Reactive Iron within Cancer Cells.

PubMed

Cioloboc, Daniela; Kennedy, Christopher; Boice, Emily N; Clark, Emily R; Kurtz, Donald M

2018-01-08

Traditional photodynamic therapy for cancer relies on dye-photosensitized generation of singlet oxygen. However, therapeutically effective singlet oxygen generation requires well-oxygenated tissues, whereas many tumor environments tend to be hypoxic. We describe a platform for targeted enhancement of photodynamic therapy that produces singlet oxygen in oxygenated environments and hydroxyl radical, which is typically regarded as the most toxic reactive oxygen species, in hypoxic environments. The 24-subunit iron storage protein bacterioferritin (Bfr) has the unique property of binding 12 heme groups in its protein shell. We inserted the isostructural photosensitizer, zinc(II) protoporphyrin IX (ZnP), in place of the hemes and extended the surface-exposed N-terminal ends of the Bfr subunits with a peptide targeting a receptor that is hyperexpressed on the cell surface of many tumors and tumor vasculature. We then loaded the inner cavity with ∼2500 irons as a ferric oxyhydroxide polymer and finally conjugated 2 kDa polyethylene glycol to the outer surface. We showed that the inserted ZnP photosensitizes generation of both singlet oxygen and the hydroxyl radical, the latter via the reaction of photoreleased ferrous iron with hydrogen peroxide. This targeted iron-loaded ZnP-Bfr construct was endocytosed by C32 melanoma cells and localized to lysosomes. Irradiating the treated cells with light at wavelengths overlapping the ZnP Soret absorption band induced photosensitized intracellular Fe 2+ release and substantial lowering of cell viability. This targeted, light-triggered production of intracellular singlet oxygen and Fenton-reactive iron could potentially be developed into a phototherapeutic adjunct for many types of cancers.

Analysis of iron, zinc, selenium and cadmium in paraffin-embedded prostate tissue specimens using inductively coupled plasma mass-spectrometry

USGS Publications Warehouse

Sarafanov, A.G.; Todorov, T.I.; Kajdacsy-Balla, A.; Gray, Michael A.; MacIas, V.; Centeno, J.A.

2008-01-01

Formalin-fixed paraffin-embedded (FFPE) tissue specimens represent a valuable and abundant resource of pathologic material for various biomedical studies. In the present study, we report the application of high-resolution inductively coupled mass-spectrometry (ICP-MS) for quantification of Fe, Zn, Se and Cd in FFPE prostate tissue. These elements have a possible role in the development of prostate diseases: while Zn and Se are needed for a healthy prostate, Cd shows multiple toxic and carcinogenic effects. Excessive accumulation of Fe induces the production of highly reactive hydroxyl radical species, which may play a role in cancer etiopathogenesis. To assess whether the levels of these metals in the FFPE prostate tissue represent their original content, we compared their levels with those in the fresh tissue (on dry weight basis) in samples obtained from 15 patients. We found that in FFPE tissue, the recoveries of Se, Fe, Cd and Zn were progressively decreased, 97??11% (r=0.88), 82??22% (r=0.86), 59??23% (r=0.69) and 24??11% (r=0.38), respectively. Thus, the use of correction factors, determined as k=0.16 for Se, k=0.20 for Fe, k=0.27 for Cd and k=0.67 for Zn, is required to estimate the retrospective levels of these elements in the parental non-processed fresh (wet) prostate tissue. The technique used in this study enables the analysis of archival FFPE prostate tissue for the concentrations of Fe, Zn, Se and Cd to study association between the levels of these metals and prostate disease. ?? 2008.

Nanoscale zero-valent iron (nZVI): aspects of the core-shell structure and reactions with inorganic species in water.

PubMed

Yan, Weile; Herzing, Andrew A; Kiely, Christopher J; Zhang, Wei-Xian

2010-11-25

Aspects of the core-shell model of nanoscale zero-valent iron (nZVI) and their environmental implications were examined in this work. The structure and elemental distribution of nZVI were characterized by X-ray energy-dispersive spectroscopy (XEDS) with nanometer-scale spatial resolution in an aberration-corrected scanning transmission electron microscope (STEM). The analysis provides unequivocal evidence of a layered structure of nZVI consisting of a metallic iron core encapsulated by a thin amorphous oxide shell. Three aqueous environmental contaminants, namely Hg(II), Zn(II) and hydrogen sulfide, were studied to probe the reactive properties and the surface chemistry of nZVI. High-resolution X-ray photoelectron spectroscopy (HR-XPS) analysis of the reacted particles indicated that Hg(II) was sequestrated via chemical reduction to elemental mercury. On the other hand, Zn(II) removal was achieved via sorption to the iron oxide shell followed by zinc hydroxide precipitation. Hydrogen sulfide was immobilized on the nZVI surface as disulfide (S(2)(2-)) and monosulfide (S(2-)) species. Their relative abundance in the final products suggests that the retention of hydrogen sulfide occurs via reactions with the oxide shell to form iron sulfide (FeS) and subsequent conversion to iron disulfide (FeS(2)). The results presented herein highlight the multiple reactive pathways permissible with nZVI owing to its two functional constituents. The core-shell structure imparts nZVI with manifold functional properties previously unexamined and grants the material with potentially new applications. Copyright © 2010 Elsevier B.V. All rights reserved.

[Dietary reference intakes of trace elements for Japanese and problems in clinical fields].

PubMed

Inoue, Yoshifumi

2016-07-01

In the dietary reference intakes, EAR(estimated average requirement), RDA(recommended dietary allowance), AL(adequate intake), DG(tentative dietary goal for preventing life style related diseases) and UL(tolerable upper intake level) of eight types of trace elements (iron: Fe, zinc: Zn, copper: Cu, manganese: Mn, iodine: I, selenium: Se, chromium: Cr, molybdenum: Mo) have been set. However, in the meals of hospitals, only iron of which has been taken into account. The content of these trace elements in the enteral nutrient released after 2000 was determined by considering the content of dietary reference intakes of trace elements for Japanese and considered so not fall into deficiency. However, enteral nutrient must be used considering the content of Zn, Cu and the Zn/Cu ratio, the selenium content, and the route of administration, in order to avoid falling into deficiency.

Removal of metal(oid)s from contaminated water using iron-coated peat sorbent.

PubMed

Kasiuliene, Alfreda; Carabante, Ivan; Bhattacharya, Prosun; Caporale, Antonio Giandonato; Adamo, Paola; Kumpiene, Jurate

2018-05-01

This study aimed at combining iron and peat to produce a sorbent suitable for a simultaneous removal of cations and anions from a solution. Peat powder, an industrial residue, was coated with iron by immersing peat into iron salt solutions. The adsorption efficiency of the newly produced sorbent towards As, Cr, Cu and Zn was tested by means of batch adsorption experiments at a constant pH value of 5. Coating of Fe on peat significantly increased the adsorption of As (from <5% to 80%) and Cr (from <3% to 25%) in comparison to uncoated peat. Removal of cations on coated peat slightly decreased (by 10-15%), yet remained within acceptable range. Electron Microscopy combined with X-Ray Energy Dispersive Spectroscopy revealed that iron coating on the peat was rather homogenous and As and Cr were abundantly adsorbed on the surface. By contrast, Cu and Zn displayed a sparing distribution on the surface of the iron coated peat. These results indicate that iron-peat simultaneously target sufficient amounts of both cations and anions and can be used for a one-step treatment of contaminated groundwater. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Characterisation of iron-rich atmospheric submicrometre particles in the roadside environment

NASA Astrophysics Data System (ADS)

Sanderson, P.; Su, S. S.; Chang, I. T. H.; Delgado Saborit, J. M.; Kepaptsoglou, D. M.; Weber, R. J. M.; Harrison, Roy M.

2016-09-01

Human exposure to ambient metallic nanoparticles is an area of great interest owing to their potential health impacts. Ambient metallic nanoparticles found in the roadside environment are contributed by combustion engines and wear of brakes, tyres and road surfaces. Submicrometre atmospheric particles collected at two UK urban sites have been subject to detailed characterisation. It is found that many metallic nanoparticles collected from roadside sampling sites are rich in iron. The Fe-rich nanoparticles can be classified into (1) high Fe content (ca 90 wt%) with each alloying element less than 1 wt%; and (2) moderate Fe content (<75 wt%) with high manganese and silicon content. Both clusters contain a variable mix of minor constituents, Mn, S and Si being most important in the high-Fe group. The moderate Fe group also contains Zn, Cu, Ba, Al and Ca. The Fe-rich nanoparticles exhibit primary particle sizes ranging between 20 and 30 nm, although some much larger particles up to around 100 nm can also be observed, along with some very small particles of 10 nm or less. These tend to agglomerate forming clusters ranging from ∼200 nm to 1 μm in diameter. The iron-rich particles observed are oxides, taking the form of spheres or multifaceted regular polyhedra. Analysis by EELS shows that both high- and moderate-Fe groups include particles of FeO, Fe3O4, α-Fe2O3 and γ-Fe2O3 of which γ-Fe2O3 is the most prominent. Internal mixing of different Fe-oxides is not observed.

Nanoscale zero-valent iron for metal/metalloid removal from model hydraulic fracturing wastewater.

PubMed

Sun, Yuqing; Lei, Cheng; Khan, Eakalak; Chen, Season S; Tsang, Daniel C W; Ok, Yong Sik; Lin, Daohui; Feng, Yujie; Li, Xiang-Dong

2017-06-01

Nanoscale zero-valent iron (nZVI) was tested for the removal of Cu(II), Zn(II), Cr(VI), and As(V) in model saline wastewaters from hydraulic fracturing. Increasing ionic strength (I) from 0.35 to 4.10 M (Day-1 to Day-90 wastewaters) increased Cu(II) removal (25.4-80.0%), inhibited Zn(II) removal (58.7-42.9%), slightly increased and then reduced Cr(VI) removal (65.7-44.1%), and almost unaffected As(V) removal (66.7-75.1%) by 8-h reaction with nZVI at 1-2 g L -1 . The removal kinetics conformed to pseudo-second-order model, and increasing I decreased the surface area-normalized rate coefficient (k sa ) of Cu(II) and Cr(VI), probably because agglomeration of nZVI in saline wastewaters restricted diffusion of metal(loid)s to active surface sites. Increasing I induced severe Fe dissolution from 0.37 to 0.77% in DIW to 4.87-13.0% in Day-90 wastewater; and Fe dissolution showed a significant positive correlation with Cu(II) removal. With surface stabilization by alginate and polyvinyl alcohol, the performance of entrapped nZVI in Day-90 wastewater was improved for Zn(II) and Cr(VI), and Fe dissolution was restrained (3.20-7.36%). The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in removal trends from Day-1 to Day-90 wastewaters was attributed to: (i) distinctive removal mechanisms of Cu(II) and Cr(VI) (adsorption, (co-)precipitation, and reduction), compared to Zn(II) (adsorption) and As(V) (bidentate inner-sphere complexation); and (ii) changes in solution speciation (e.g., from Zn 2+ to ZnCl 3 - and ZnCl 4 2- ; from CrO 4 2- to CaCrO 4 complex). Bare nZVI was susceptible to variations in wastewater chemistry while entrapped nZVI was more stable and environmentally benign, which could be used to remove metals/metalloids before subsequent treatment for reuse/disposal. Copyright © 2017 Elsevier Ltd. All rights reserved.

New method for the direct determination of dissolved Fe(III) concentration in acid mine waters

USGS Publications Warehouse

To, T.B.; Nordstrom, D. Kirk; Cunningham, K.M.; Ball, J.W.; McCleskey, R. Blaine

1999-01-01

A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II) >> Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), AI(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2 ??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II)???Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), Al(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2/??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.

Autumnal resorption and accretion of trace metals in gallery forest tree. [Quercus macrocarpa, Quercus muehlenbergii, Fraxinus pennsylvanica, Celtis occidentalis, and Ulmus rubra

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

Killingbeck, K.T.

1985-02-01

Autumnal resorption and accretion of copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) were measured in the foliage of five gallery forest trees species on the Konza Prairie Research Natural Area. Presenescence and postabscission leaves from five trees each of Quercus macrocarpa, Q. muehlenbergii, Fraxinus pennsylvanica, Celtis occidentalis, and Ulmus rubra, were sampled. Three species resorbed 19, 25, and 26%, respectively, of their presenescence foliar Zn, and one species resorbed 35% of its presenescence foliar Fe. This validates the prediction made by others that Zn and Fe are withdrawn from the senescing foliage of at least some deciduous species.more » Net accretions of Cu (43, 44, 69%), Fe (36, 40%), and Mn (19, 57%) occurred during the same period. The two oak species were responsible for most of the resorption, while the three non-oak species accounted for all of the significant accretions. Such well-defined differences in element conservation may influence interspecific competition by accentuating, or compensating for, species differences in element uptake ability and element use efficiency. Demand:availability ratios proved useful in predicting the likelihood that a given element would be conserved through resorption.« less

The influence of manganese treatment on the distribution of metal elements in rats and the protection by sodium para-amino salicylic acid.

PubMed

Yuan, Zong-Xiang; Chen, Hai-Bin; Li, Shao-Jun; Huang, Xiao-Wei; Mo, Yu-Huan; Luo, Yi-Ni; He, Sheng-Nan; Deng, Xiang-Fa; Lu, Guo-Dong; Jiang, Yue-Ming

2016-07-01

Manganese (Mn) overexposure induced neurological damages, which could be potentially protected by sodium para-aminosalicylic acid (PAS-Na). In this study, we systematically detected the changes of divalent metal elements in most of the organs and analyzed the distribution of the metals in Mn-exposed rats and the protection by PAS-Na. Sprague Dawley (SD) rats received intraperitoneal injections of 15mg/kg MnCl2·4H2O (5d/week for 3 weeks), followed by subcutaneous (back) injections of PAS-Na (100 and 200mg/kg, everyday for 5 weeks). The concentrations of Mn and other metal elements [Iron (Fe), Copper (Cu), Zinc (Zn), Magnesium (Mg), Calcium (Ca)] in major organs (liver, spleen, kidney, thighbone and iliac bone, cerebral cortex, hippocampus and testes) and blood by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Mn overexposure significantly increased Mn in most organs, Fe and Zn in liver, Fe and Mg in blood; however decreased Fe, Cu, Zn, Mg and Ca in cortex, Cu and Zn in kidney, Cu and Mg in iliac bone, and Zn in blood. In contrast, PAS-Na treatment restored most changes particularly in cortex. In conclusion, excessive Mn exposure disturbed the balance of other metal elements but PAS-Na post-treatments could restore these alterations. Copyright © 2016 Elsevier GmbH. All rights reserved.

Ethnic studies of dietary intakes of zinc, copper, iron, and calcium

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

Matthews, C.; Figueroa, M.; Tam, C.F.

1986-01-01

Immigrants, such as S.E. Asians who live in the L.A. area, often suffer high incidences of diseases. It is of interest to examine ethnic eating patterns whether they influence dietary Zn, Cu, Fe, Ca, protein and Kcal, which are essential for proper immune functions. Three-day dietary intake of adult ethnic groups, Asian(A)(N=18), Caucasian(C)(26), Black(B)(7), Latino(L)(12), Middle Easterner(ME)(9) and Filipino(F)(6) were analyzed for Zn, Cu, Fe, Ca, protein and Kcal by Ohio Data Base Foods II(ODBF) then statistically compared by PROPHET. Zn and Cu were also analyzed by hand calculation(HC). No statistical differences were observed for mean Zn between groups analyzedmore » by ODBF whereas HC of mean Zn between A vs C (A=11.3 +/- S.D.2.9 mg vs C=8.8 +/- 2.8, P<0.01) and A vs L (11.3+/-2.9 vs L=8.9+/-2.2, P<0.05) were statistically different. No differences were found for Cu between the groups. By ODBF, none of mean Cu or Zn met 2/3 RDA for any of the groups. For Fe, no differences were found between groups and only 50% of the subjects met 2/3 RDA. Significant differences were observed for Ca only between A vs C and B vs C. Both A and B had lower mean Ca than C. All groups had adequate protein. Mean Kcal of all groups were found to be at or about 2/3 RDA. Both insufficient Kcal and eating patterns contribute to inadequate Cu, Zn, and Fe intakes and hence may affect immune competency.« less

Ion exchange treatment of rinse water generated in the galvanizing process.

PubMed

Marañón, Elena; Fernández, Yolanda; Castrillón, Leonor

2005-01-01

A study was conducted of the viability of using the cationic exchange resins Amberlite IR-120 and Lewatit SP-112 to treat rinse water generated in the galvanizing process as well as acidic wastewater containing zinc (Zn) and iron (Fe). Solutions containing either 100 mg/L of Zn at pH 5.6 (rinse water) or Fe and Zn at concentrations of 320 and 200 mg/L at pH 1.5 (acidic water), respectively, were percolated through packed beds until the resins were exhausted. Breakthrough capacities obtained ranged between 1.1 and 1.5 meq metal/mL resin. The elution of metal and the regeneration of resins were performed with hydrochloric acid. The influence of the flowrate used during the loading stage was also studied, with 0.5 bed volumes/min (3.2 cm/min) found to be the optimum flowrate.

Major and trace element composition of copiapite-group minerals and coexisting water from the Richmond mine, Iron Mountain, California

USGS Publications Warehouse

Jamieson, H.E.; Robinson, C.; Alpers, Charles N.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Peterson, Ronald C.

2005-01-01

Copiapite-group minerals of the general formula AR4 (SO4)6(OH)2??nH2O, where A is predominantly Mg, Fe2+, or 0.67Al3+, R is predominantly Fe3+, and n is typically 20, are among several secondary hydrous Fe sulfates occurring in the inactive mine workings of the massive sulfide deposit at Iron Mountain, CA, a USEPA Superfund site that produces extremely acidic drainage. Samples of copiapite-group minerals, some with coexisting water, were collected from the Richmond mine. Approximately 200 mL of brownish pore water with a pH of -0.9 were extracted through centrifugation from a 10-L sample of moist copiapite-group minerals taken from pyritic muck piles. The pore water is extremely rich in ferric iron (Fe3+=149 g L-1, FeT=162 g L-1 and has a density of 1.52 g mL-1. The composition of the pore water is interpreted in the context of published phase relations in the Fe2O3- SO3-H2O system and previous work on the chemistry of extremely acid mine waters and associated minerals in the Richmond mine. Two distinct members of the copiapite mineral group were identified in the samples with coexisting water: (1) abundant magnesiocopiapite consisting of platy crystals 10 to 50 ??m and (2) minor aluminocopiapite present as smaller platy crystals that form spheroidal aggregates. The average composition (n=5) of the magnesiocopiapite is (Mg0.90Fe0.172+ Zn0.02Cu0.01)???1.10(Fe3.833+Al0.09)???3.92(SO4) 6.00(OH)1.96??20H2O. Bulk compositions determined by digestion and wet-chemical analysis are consistent with the microanalytical results. These results suggest that magnesiocopiapite is the least soluble member of the copiapite group under the prevailing conditions. Micro-PIXE analysis indicates that the copiapite-group minerals in this sample sequester Zn (average 1420 ppm), with lesser amounts of Cu (average 270 ppm) and As (average 64 ppm). ?? 2004 Elsevier B.V. All rights reserved.

Spectroscopic and computational study of a nonheme iron nitrosyl center in a biosynthetic model of nitric oxide reductase.

PubMed

Chakraborty, Saumen; Reed, Julian; Ross, Matthew; Nilges, Mark J; Petrik, Igor D; Ghosh, Soumya; Hammes-Schiffer, Sharon; Sage, J Timothy; Zhang, Yong; Schulz, Charles E; Lu, Yi

2014-02-24

A major barrier to understanding the mechanism of nitric oxide reductases (NORs) is the lack of a selective probe of NO binding to the nonheme FeB center. By replacing the heme in a biosynthetic model of NORs, which structurally and functionally mimics NORs, with isostructural ZnPP, the electronic structure and functional properties of the FeB nitrosyl complex was probed. This approach allowed observation of the first S=3/2 nonheme {FeNO}(7) complex in a protein-based model system of NOR. Detailed spectroscopic and computational studies show that the electronic state of the {FeNO}(7) complex is best described as a high spin ferrous iron (S=2) antiferromagnetically coupled to an NO radical (S=1/2) [Fe(2+)-NO(.)]. The radical nature of the FeB -bound NO would facilitate N-N bond formation by radical coupling with the heme-bound NO. This finding, therefore, supports the proposed trans mechanism of NO reduction by NORs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-Ion Distribution and Oxygen Vacancies That Determine the Activity of Magnetically Recoverable Catalysts in Methanol Synthesis.

PubMed

Oracko, Troy; Jaquish, Rigel; Losovyj, Yaroslav B; Morgan, David Gene; Pink, Maren; Stein, Barry D; Doluda, Valentin Yu; Tkachenko, Olga P; Shifrina, Zinaida B; Grigoriev, Maxim E; Sidorov, Alexander I; Sulman, Esther M; Bronstein, Lyudmila M

2017-10-04

Here, we report on the development of novel Zn-, Zn-Cr-, and Zn-Cu-containing catalysts using magnetic silica (Fe 3 O 4 -SiO 2 ) as the support. Transmission electron microscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy (XPS) showed that the iron oxide nanoparticles are located in mesoporous silica pores and the magnetite (spinel) structure remains virtually unchanged despite the incorporation of Zn and Cr. According to XPS data, the Zn and Cr species are intermixed within the magnetite structure. In the case of the Zn-Cu-containing catalysts, a separate Cu 2 O phase was also observed along with the spinel structure. The catalytic activity of these catalysts was tested in methanol synthesis from syngas (CO + H 2 ). The catalytic experiments showed an improved catalytic performance of Zn- and Zn-Cr-containing magnetic silicas compared to that of the ZnO-SiO 2 catalyst. The best catalytic activity was obtained for the Zn-Cr-containing magnetic catalyst prepared with 1 wt % Zn and Cr each. X-ray absorption spectroscopy demonstrated the presence of oxygen vacancies near Fe and Zn in Zn-containing, and even more in Zn-Cr-containing, magnetic silica (including oxygen vacancies near Cr ions), revealing a correlation between the catalytic properties and oxygen vacancies. The easy magnetic recovery, robust synthetic procedure, and high catalytic activity make these catalysts promising for practical applications.

Preferential depletion of zinc within Costa Rica upwelling dome creates conditions for zinc co-limitation of primary production

PubMed Central

Dreux Chappell, P.; Vedmati, Jagruti; Selph, Karen E.; Cyr, Heather A.; Jenkins, Bethany D.; Landry, Michael R.; Moffett, James W.

2016-01-01

The Costa Rica Dome (CRD) is a wind-driven feature characterized by high primary production and an unusual cyanobacterial bloom in surface waters. It is not clear whether this bloom arises from top-down or bottom-up processes. Several studies have argued that trace metal geochemistry within the CRD contributes to the composition of the phytoplankton assemblages, since cyanobacteria and eukaryotic phytoplankton have different transition metal requirements. Here, we report that total dissolved zinc (Zn) is significantly depleted relative to phosphate (P) and silicate (Si) within the upper water column of the CRD compared with other oceanic systems, and this may create conditions favorable for cyanobacteria, which have lower Zn requirements than their eukaryotic competitors. Shipboard grow-out experiments revealed that while Si was a limiting factor under our experimental conditions, additions of Si and either iron (Fe) or Zn led to higher biomass than Si additions alone. The addition of Fe and Zn alone did not lead to significant enhancements. Our results suggest that the depletion of Zn relative to P in upwelled waters may create conditions in the near-surface waters that favor phytoplankton with low Zn requirements, including cyanobacteria. PMID:27275028

Charge-density study on layered oxyarsenides (LaO)MAs (M = Mn, Fe, Ni, Zn)

NASA Astrophysics Data System (ADS)

Takase, Kouichi; Hiramoto, Shozo; Fukushima, Tetsuya; Sato, Kazunori; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

2017-12-01

Using synchrotron X-ray powder diffraction, we investigate the charge-density distributions of the layered oxypnictides (LaO)MnAs, (LaO)FeAs, (LaO)NiAs, and (LaO)ZnAs, which are an antiferromagnetic semiconductor, a parent material of an iron-based superconductor, a low-temperature superconductor, and a non-magnetic semiconductor, respectively. For the metallic samples, clear charge densities are observed in both the transition-metal pnictide layers and the rare-earth-oxide layers. However, in the semiconducting samples, there is no finite charge density between the transition-metal element and As. These differences in charge density reflect differences in physical properties. First-principles calculations using density functional theory reproduce the experimental results reasonably well.

High-resolution analytical imaging and electron holography of magnetite particles in amyloid cores of Alzheimer’s disease

PubMed Central

Plascencia-Villa, Germán; Ponce, Arturo; Collingwood, Joanna F.; Arellano-Jiménez, M. Josefina; Zhu, Xiongwei; Rogers, Jack T.; Betancourt, Israel; José-Yacamán, Miguel; Perry, George

2016-01-01

Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles. PMID:27121137

High-resolution analytical imaging and electron holography of magnetite particles in amyloid cores of Alzheimer’s disease

NASA Astrophysics Data System (ADS)

Plascencia-Villa, Germán; Ponce, Arturo; Collingwood, Joanna F.; Arellano-Jiménez, M. Josefina; Zhu, Xiongwei; Rogers, Jack T.; Betancourt, Israel; José-Yacamán, Miguel; Perry, George

2016-04-01

Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles.

Cation Distribution and Local Configuration of Fe 2+ Ions in Structurally Nonequivalent Lattice Sites of Heterometallic Fe(II)/ M(II) ( M = Mn, Co, Ni, Cu, Zn) Diaquadiformato Complexes

NASA Astrophysics Data System (ADS)

Devillers, M.; Ladrière, J.

1993-03-01

57Fe Mössbauer investigations are carried out on a wide series of heterometallic diaquadiformato Fe(II)/ M(II) complexes with M = Mn, Co, Ni, Cu, and Zn to provide a local picture of the coordination environment of the 57Fe 2+ ions as a function of (i) the nature of the host cation and (ii) the relative amounts of both metals in the matrix (between 50 and 0.25 at.% Fe). Information is obtained on the quantitative distribution of both metals between the two structurally nonequivalent lattice sites and on the local geometry around the dopant atom in each crystal site. In the mixed Fe-Cu complexes. Fe 2+ ions are preferentially incorporated in the tetrahydrated site; in Cu-rich Fe xCu 1- x(HCO 2) 2· 2H 2O, the 57Fe 2+ ions located in the hexaformato-coordinated site are surrounded by an axially compressed octahedron of formate ligands which contrasts with the elongated configuration observed in the pure iron compound and in the other mixed systems. Semiquantitative estimations of the tetragonal field splitting and of the extent of metal-ligand interactions are proposed from the temperature dependence of the quadrupole splitting values.

A time-course analysis of changes in cerebral metal levels following a controlled cortical impact.

PubMed

Portbury, Stuart D; Hare, Dominic J; Sgambelloni, Charlotte; Finkelstein, David I; Adlard, Paul A

2016-02-01

Traumatic brain injury (TBI) is complicated by a sudden and dramatic change in brain metal levels, including iron (Fe), copper (Cu) and zinc (Zn). Specific 'metallo-pathological' features of TBI include increased non-heme bound Fe and the liberation of free Zn ions, both of which may contribute to the pathogenesis of TBI. To further characterise the metal dyshomeostasis that occurs following brain trauma, we performed a quantitative time-course survey of spatial Fe, Cu and Zn distribution in mice receiving a controlled cortical impact TBI. Images of brain metal levels produced using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in the upper quadrant of the ipsilateral hemisphere were compared to the corresponding contralateral hemisphere, together with regional areas radiating toward the center of the brain from the site of lesion. Significant regional and time point specific elevations in Fe, Zn and Cu were detected immediately and up to 28 days after TBI. The magnitude and timeframe of many of these changes suggest that TBI results in a pronounced and sustained alteration in normal metal levels within the brain. Such alterations are likely to play a role in both the short- and long-term consequences of head trauma and suggest that pharmacological modulation to normalize these metal levels may be efficacious in improving functional outcome.

Dye-sensitized solar cell characteristics of nanocomposite zinc ferrite working electrode: effect of composite precursors and titania as a blocking layer on photovoltaic performance.

PubMed

Habibi, Mohammad Hossein; Habibi, Amir Hossein; Zendehdel, Mahmoud; Habibi, Mehdi

2013-06-01

This research investigates the performance of a zinc ferrite (ZF) as working electrodes in a dye-sensitized solar cell (DSSC). This ZF working electrode was prepared by sol-gel and thermal decomposition of four different precursors including: zinc acetate dihydrate (Zn(CH3COO)2·2H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), iron(III) acetate; Fe(C2H3O2)3, and zinc nitrate hexahydrate, Zn(NO3)2·6H2O. The effects of annealing temperature and precursors on the structural, morphological, and optical properties were investigated. The field emission scanning electron microscope images (FESEM) and scanning electron microscopy (SEM) show that ZFe films are polycrystalline in nature and homogeneous with densely packed grains. Nanoporous zinc ferrite coatings were prepared by doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in DSSC. In all DSSCs, platinized FTO and [Co(bpy)3](2+/3+) in 3-methoxy proponitrile were used as counter electrode and redox mediator system respectively. Comparing the fill factors of four different zinc ferrite nanocomposites, the highest fill factor was for ZnFe2O4-TBL sample. Cell fabricated with ZnFeA working electrode shows relatively higher Jsc. Copyright © 2013 Elsevier B.V. All rights reserved.

Role of root exudates in dissolution of Cd containing iron oxides

NASA Astrophysics Data System (ADS)

Rosenfeld, C.; Martinez, C. E.

2011-12-01

Dissolved organic matter (DOM) in the rhizosphere contains organic acids, amino acids and more complex organic molecules that can substantially impact the solubility of soil solid phases. Plant roots and soil microorganisms contribute a large fraction of these organic compounds to DOM, potentially accelerating the transfer of solid phase elements into solution. In highly contaminated soils, heavy metals such as Cd are commonly found coprecipitated with common minerals (e.g. iron oxides). Introducing or changing vegetation on these contaminated soils may increase DOM levels in the soil pore fluids and thus enhance the biological and chemical weathering of soil minerals. Here, we investigate the role of root exudates on mineral dissolution and Cd mobility in contaminated soils. We hypothesize that plant exudates containing nitrogen and sulfur functional groups will dissolve Cd-containing mineral phases to a greater extent than exudates containing only oxygen functional groups, resulting in higher Cd concentrations in solution. Two different iron oxide mineral phases were utilized in a laboratory-scale model study system investigating the effects of low molecular weight, oxygen-, nitrogen-, and sulfur-containing organic compounds on mineral dissolution. Goethite (α-FeOOH) was synthesized in the laboratory with 0, 2.4, 5, and 100 theoretical mol% Cd, and franklinite (ZnFe2O4) was prepared with 0, 10, and 25 theoretical mol% Cd. Phase identity of all minerals was verified with X-ray diffraction (XRD). All minerals were reacted with 0.01 mM solutions containing one of four different organic ligands (oxalic acid, citric acid, histidine or cysteine) and aliquots of these solutions were sampled periodically over 40 days. Results from solution samples suggest that oxalic acid, citric acid, and histidine consistently increase mineral dissolution relative to the control (no organic compound present) while cysteine consistently inhibits dissolution relative to the control in all minerals. Increasing Cd substitution in the franklinite resulted in increased release of Fe and Zn to solution in the presence of these organic compounds, while increasing Cd substitution in the goethite generally limited Fe release to solution. In the case of cysteine, sulfur concentrations in solution decrease over time in the presence of Cd-containing minerals, indicating strong binding of the cysteine compound to the mineral surface, inhibiting Cd dissolution from the minerals. Our work indicates that amino acids present in biological soil exudates, in addition to organic acids, may have substantial impacts on iron oxide dissolution in soils, altering the availability of both bioessential (e.g., Fe and Zn) and non-essential, or potentially toxic, (e.g., Cd) elements.

Superparamagnetic behavior of heat treated Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ferrite nanoparticles studied by Mössbauer spectroscopy

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

Srinivas, Ch., E-mail: srinivas.chintoju75@gmail.com; Prasad, S. A. V.; Singh, S. B.

2016-05-23

Nanoparticles of Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} ferrite have been synthesized by co-precipitation method. XRD and Mössbauer spectroscopic results of Mg{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} annealed at 200 °C, 500 °C and 800 °C are reported. It was observed that the crystallite size increases and the lattice parameter decreases with increase in annealing temperature. The observed decrease in lattice strain supports the increase in crystallite size. The Mössbauer spectra of the samples annealed at 200 °C and 500 °C exhibits superparamagnetic doublets whereas the Mössbauer spectrum of the sample annealed at 800 °C exhibits paramagnetic doublet along with weak sextetmore » of hyperfine interaction. The values of isomer shift resemble the presence of high spin iron ions. The studied ferrite nanoparticles are suitable for biomedical applications. The results are incorporated employing core-shell model and cation redistribution.« less

A Low-Cost Neutral Zinc-Iron Flow Battery with High Energy Density for Stationary Energy Storage.

PubMed

Xie, Congxin; Duan, Yinqi; Xu, Wenbin; Zhang, Huamin; Li, Xianfeng

2017-11-20

Flow batteries (FBs) are one of the most promising stationary energy-storage devices for storing renewable energy. However, commercial progress of FBs is limited by their high cost and low energy density. A neutral zinc-iron FB with very low cost and high energy density is presented. By using highly soluble FeCl 2 /ZnBr 2 species, a charge energy density of 56.30 Wh L -1 can be achieved. DFT calculations demonstrated that glycine can combine with iron to suppress hydrolysis and crossover of Fe 3+ /Fe 2+ . The results indicated that an energy efficiency of 86.66 % can be obtained at 40 mA cm -2 and the battery can run stably for more than 100 cycles. Furthermore, a low-cost porous membrane was employed to lower the capital cost to less than $ 50 per kWh, which was the lowest value that has ever been reported. Combining the features of low cost, high energy density and high energy efficiency, the neutral zinc-iron FB is a promising candidate for stationary energy-storage applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties

DOE PAGES

Sougrati, Moulay T.; Darwiche, Ali; Liu, Xiaohiu; ...

2016-03-16

Here we report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as a negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on 57Fe M ssbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe NCN into Li/Na NCN bonds during discharge and charge. These new electrode materials exhibit higher capacity compared to well-established negative electrode references such as graphite or hard carbon. Contrary to its oxide analogue, iron carbodiimide does not requiremore » heavy treatments (nanoscale tailoring, sophisticated textures, coating etc.) to obtain long cycle life with density current as high as 9 A/g -1 for hundreds of charge/discharge cycles. Similar to the iron compound, several other transition-metal carbodiimides M x(NCN) y with M = Mn, Cr, Zn can cycle successfully versus lithium and sodium. Ultimately, their electrochemical activity and performances open the way to the design of a novel family of anode materials.« less

HUMAN SCALP HAIR: AN ENVIRONMENTAL EXPOSURE INDEX FOR TRACE ELEMENTS. II. SEVENTEEN TRACE ELEMENTS IN FOUR NEW JERSEY COMMUNITIES (1972)

EPA Science Inventory

Seventeen trace elements - arsenic (As), barium (Ba), boron (B), cadmium (Cd), chromium (Cr), copper (Cu), Iron (Fe), lead (Pb), lithium (Li), manganese (Mn), mercury (Hg), nickle (Ni), selenium (Se), silver (Ag), tin (Sn), vanadium (V), and zinc (Zn) - were measured in human sca...

Chemical Compositions of Kinematically Selected Outer Halo Stars

NASA Astrophysics Data System (ADS)

Zhang, Lan; Ishigaki, Miho; Aoki, Wako; Zhao, Gang; Chiba, Masashi

2009-12-01

Chemical abundances of 26 metal-poor dwarfs and giants are determined from high-resolution and high signal-to-noise ratio spectra obtained with the Subaru/High Dispersion Spectrograph. The sample is selected so that most of the objects have outer-halo kinematics. Self-consistent atmospheric parameters were determined by an iterative procedure based on spectroscopic analysis. Abundances of 13 elements, including α-elements (Mg, Si, Ca, Ti), odd-Z light elements (Na, Sc), iron-peak elements (Cr, Mn, Fe, Ni, Zn), and neutron-capture elements (Y, Ba), are determined by two independent data reduction and local thermodynamic equillibrium analysis procedures, confirming the consistency of the stellar parameters and abundances results. We find a decreasing trend of [α/Fe] with increasing [Fe/H] for the range of -3.5< [Fe/H] <-1, as found by Stephens & Boesgaard. [Zn/Fe] values of most objects in our sample are slightly lower than the bulk of halo stars previously studied. These results are discussed as possible chemical properties of the outer halo in the Galaxy. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

A synthesis of mineralization styles and geodynamic settings of the Paleozoic and Mesozoic metallic ore deposits in the Altay Mountains, NW China

NASA Astrophysics Data System (ADS)

Yang, Fuquan; Geng, Xinxia; Wang, Rui; Zhang, Zhixin; Guo, Xuji

2018-06-01

The Altay Mountains within the Xinjiang region of northwestern China hosts major metallic ore deposits. Here we review the geological characteristics, metallogenic features and tectonic settings of these deposits. The metallic ore deposits in the Altay Mountains occur mainly within four regions: North Altay, Central Altay, South Altay and Erqis. We recognize seven types of metallic ore deposits in the Altay Mountains: VMS, submarine volcanogenic iron, magmatic, skarn, pegmatite, hydrothermal vein (Cu-Zn, Fe) and orogenic gold. Among these types, the VMS, pegmatite, orogenic gold and skarn deposits are the most common. Most of the rare metal pegmatite deposits are distributed in Central Altay, with only a few in South Altay. The VMS, submarine volcanogenic type iron and skarn-type deposits are distributed in South Altay, whereas the orogenic-type gold deposits are distributed in the Erqis Fault belt. The hydrothermal vein-type deposits occur in the Erqis Fault belt and Chonghu'er Basin in South Altay. Magmatic-type deposits are mostly in the Erqis Fault belt and Central Altay. Based on isotopic age data, the VMS, submarine volcanogenic-type Fe and skarn-type Cu, Pb, Zn, Fe mineralization occurred during Early-Middle Devonian (∼410-377 Ma), orogenic-type Au, magmatic-type Cu-Ni, and a small number of skarn-type Fe, hydrothermal vein-type Cu-Zn, pegmatite-type rare-metal deposits in Early-Middle Permian (293-261 Ma), pegmatite-type rare-metal deposits, few skarn-type Fe deposit in Early-Middle Triassic (248-232 Ma), and dominantly represented by pegmatite-type rare-metal deposits in Late Triassic-Early Jurassic (223-180 Ma). The metallic ore deposits in the Altay Mountains formed in various tectonic settings, such as the Early-Middle Devonian continental arc and oceanic island arc, Early-Middle Permian post-collisional extensional setting, and Triassic-Early Jurassic intracontinental setting.

Long-term variations in sediment heavy metals of a reservoir with changing trophic states: Implications for the impact of climate change.

PubMed

Wu, Qiong; Qi, Jun; Xia, Xinghui

2017-12-31

Two dated sediment cores from the Miyun Reservoir of Beijing in China were analyzed to reconstruct the pollution history of heavy metals including cadmium (Cd), chromium (Cr), iron (Fe), nickel (Ni), and zinc (Zn) as well as phosphorus (P). Enrichment factor (EF) and geoaccumulation index (I geo ) were applied to assess the enrichment status of heavy metals. Average EF and I geo values indicated that the studied heavy metals in the sediments mainly originated from non-point source pollution and soil-water erosion, showing low ecological risks. In addition, correlation analysis and principal component analysis (PCA) identified that Cd, Zn, and P were mainly from agricultural diffusion pollution caused by utilization of the phosphate fertilizer; Zn, Ni, and Cr originated from soil erosion. PCA analysis was further conducted to investigate the relationships among meteorological factors, algae-dominant total organic carbon (TOC), and heavy metals. Results showed that algae-dominant TOC had strong positive correlation with temperature, which can be explained by that increased temperature accelerated the growth of algae. Meanwhile the opposite loadings between algae-dominant TOC and heavy metal suggested that primary production played an important role in migration and transformation of metals. Moreover, stepwise multiple regression models showed that Fe was sensitive to temperature, which accounted for approximately 39.0% and 40.1% of the variations in Fe of two sediment cores, respectively. Fe showed significant decreasing trends during the past 50years. Reductive environment of water-sediment interface caused by increasing temperature probably contributed to the restoration of ferric iron, resulting in the release of soluble Fe to overlying waters. Future climate change with elevated temperature and extreme weather events will aggravate the ecological risk of heavy metals in water environment due to the enhanced leaching effect and non-point source pollution as well as the release of heavy metals from sediments to water environment. Copyright © 2017. Published by Elsevier B.V.

Nanocompounds of iron and zinc: their potential in nutrition

NASA Astrophysics Data System (ADS)

Zimmermann, Michael B.; Hilty, Florentine M.

2011-06-01

Recent studies suggest nanostructured oxides and phosphates of Fe and atomically mixed Fe/Zn may be useful for nutritional applications. These compounds may have several advantages over existing fortificants, such as ferrous sulfate (FeSO4), NaFeEDTA and electrolytic iron. Because of their very low solubility and formation of soft agglomerates of micron size at neutral pH as well as their light native color, they tend to be less reactive in difficult-to-fortify foods and thus have superior sensory performance. At gastric pH the soft agglomerates break up and the Fe compounds rapidly and completely dissolve due to their very high surface area. This results in in vitro solubility and in vivo bioavailability comparable to FeSO4. Doping with Mg and/or Ca may increase solubility and improve sensory characteristics by lightening color. Feeding the nanostructured compounds at 150-400 µg Fe day-1 for 15 days to weanling rats in two studies did not induce measurable histological or biochemical adverse effects. No significant Fe was detected in the submucosa of the gastrointestinal tract or lymphatic tissues, suggesting that the nanosized Fe is absorbed through usual non-heme Fe absorption pathways. Thus, these novel compounds show promise as food fortificants or supplements.

Distribution of potentially toxic elements (PTEs) in tailings, soils, and plants around Gol-E-Gohar iron mine, a case study in Iran.

PubMed

Soltani, Naghmeh; Keshavarzi, Behnam; Moore, Farid; Sorooshian, Armin; Ahmadi, Mohamad Reza

2017-08-01

This study investigated the concentration of potentially toxic elements (PTEs) including Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, V, and Zn in 102 soils (in the Near and Far areas of the mine), 7 tailings, and 60 plant samples (shoots and roots of Artemisia sieberi and Zygophylum species) collected at the Gol-E-Gohar iron ore mine in Iran. The elemental concentrations in tailings and soil samples (in Near and Far areas) varied between 7.4 and 35.8 mg kg -1 for As (with a mean of 25.39 mg kg -1 for tailings), 7.9 and 261.5 mg kg -1 (mean 189.83 mg kg -1 for tailings) for Co, 17.7 and 885.03 mg kg -1 (mean 472.77 mg kg -1 for tailings) for Cu, 12,500 and 400,000 mg kg -1 (mean 120,642.86 mg kg -1 for tailings) for Fe, and 28.1 and 278.1 mg kg -1 (mean 150.29 mg kg -1 for tailings) for Ni. A number of physicochemical parameters and pollution index for soils were determined around the mine. Sequential extractions of tailings and soil samples indicated that Fe, Cr, and Co were the least mobile and that Mn, Zn, Cu, and As were potentially available for plants uptake. Similar to soil, the concentration of Al, As, Co, Cr, Cu, Fe, Mn, Mo, Ni, and Zn in plant samples decreased with the distance from the mining/processing areas. Data on plants showed that metal concentrations in shoots usually exceeded those in roots and varied significantly between the two investigated species (Artemisia sieberi > Zygophylum). All the reported results suggest that the soil and plants near the iron ore mine are contaminated with PTEs and that they can be potentially dispersed in the environment via aerosol transport and deposition.

Deciphering Genomic Regions for High Grain Iron and Zinc Content Using Association Mapping in Pearl Millet

PubMed Central

Anuradha, N.; Satyavathi, C. Tara; Bharadwaj, C.; Nepolean, T.; Sankar, S. Mukesh; Singh, Sumer P.; Meena, Mahesh C.; Singhal, Tripti; Srivastava, Rakesh K.

2017-01-01

Micronutrient malnutrition, especially deficiency of two mineral elements, iron [Fe] and zinc [Zn] in the developing world needs urgent attention. Pearl millet is one of the best crops with many nutritional properties and is accessible to the poor. We report findings of the first attempt to mine favorable alleles for grain iron and zinc content through association mapping in pearl millet. An association mapping panel of 130 diverse lines was evaluated at Delhi, Jodhpur and Dharwad, representing all the three pearl millet growing agro-climatic zones of India, during 2014 and 2015. Wide range of variation was observed for grain iron (32.3–111.9 ppm) and zinc (26.6–73.7 ppm) content. Genotyping with 114 representative polymorphic SSRs revealed 0.35 mean gene diversity. STRUCTURE analysis revealed presence of three sub-populations which was further supported by Neighbor-Joining method of clustering and principal coordinate analysis (PCoA). Marker-trait associations (MTAs) were analyzed with 267 markers (250 SSRs and 17 genic markers) in both general linear model (GLM) and mixed linear model (MLM), however, MTAs resulting from MLM were considered for more robustness of the associations. After appropriate Bonferroni correction, Xpsmp 2261 (13.34% R2-value), Xipes 0180 (R2-value of 11.40%) and Xipes 0096 (R2-value of 11.38%) were consistently associated with grain iron and zinc content for all the three locations. Favorable alleles and promising lines were identified for across and specific environments. PPMI 1102 had highest number (7) of favorable alleles, followed by four each for PPMFeZMP 199 and PPMI 708 for across the environment performance for both grain Fe and Zn content, while PPMI 1104 had alleles specific to Dharwad for grain Fe and Zn content. When compared with the reference genome Tift 23D2B1-P1-P5, Xpsmp 2261 amplicon was identified in intergenic region on pseudomolecule 5, while the other marker, Xipes 0810 was observed to be overlapping with aspartic proteinase (Asp) gene on pseudomolecule 3. Thus, this study can help in breeding new lines with enhanced micronutrient content using marker-assisted selection (MAS) in pearl millet leading to improved well-being especially for women and children. PMID:28507551

Enhanced magnetic domain relaxation frequency and low power losses in Zn2+ substituted manganese ferrites potential for high frequency applications

NASA Astrophysics Data System (ADS)

Praveena, K.; Chen, Hsiao-Wen; Liu, Hsiang-Lin; Sadhana, K.; Murthy, S. R.

2016-12-01

Nowadays electronic industries prerequisites magnetic materials, i.e., iron rich materials and their magnetic alloys. However, with the advent of high frequency applications, the standard techniques of reducing eddy current losses, using iron cores, were no longer efficient or cost effective. Current market trends of the switched mode power supplies industries required even low energy losses in power conversion with maintenance of adequate initial permeability. From the above point of view, in the present study we aimed at the production of Manganese-Zinc ferrites prepared via solution combustion method using mixture of fuels and achieved low loss, high saturation magnetization, high permeability, and high magnetic domain relaxation frequency. The as-synthesized Zn2+ substituted MnFe2O4 were characterized by X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The fractions of Mn2+, Zn2+ and Fe2+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of all ferrite samples were estimated by Raman scattering spectroscopy. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (fr) was increased with the increase in grain size. The real and imaginary part of permeability (μ‧ and μ″) increased with frequency and showed a maximum above 100 MHz. This can be explained on the basis of spin rotation and domain wall motion. The saturation magnetization (Ms), remnant magnetization (Mr) and magneton number (μB) decreased gradually with increasing Zn2+ concentration. The decrease in the saturation magnetization was discussed with Yafet-Kittel (Y-K) model. The Zn2+ concentration increases the relative number of ferric ions on the A sites, reduces the A-B interactions. The frequency dependent total power losses decreased as the zinc concentration increased. At 1 MHz, the total power loss (Pt) changed from 358 mW/cm3 for x=0-165 mW/cm3 for x=0.9. Pt for all the Zn doped samples exhibited the temperature stability up to 100 °C.

Effect of accelerated carbonation and zero valent iron on metal leaching from bottom ash.

PubMed

Nilsson, M; Andreas, L; Lagerkvist, A

2016-05-01

About 85% of the ashes produced in Sweden originated from the incineration of municipal solid waste and biofuel. The rest comes from the thermal treatment of recycled wood, peat, charcoal and others. About 68% of all ashes annually produced in Sweden are used for constructions on landfills, mainly slopes, roads and embankments, and only 3% for construction of roads and working surfaces outside the landfills (SCB, 2013). Since waste bottom ash (BA) often has similar properties to crushed bedrock or gravel, it could be used for road constructions to a larger extent. However, the leaching of e.g. Cr, Cu, Mo, Pb and Zn can cause a threat to the surrounding environment if the material is used as it is. Carbonation is a commonly used pre-treatment method, yet it is not always sufficient. As leaching from aged ash is often controlled by adsorption to iron oxides, increasing the number of Fe oxide sorption sites can be a way to control the leaching of several critical elements. The importance of iron oxides as sorption sites for metals is known from both mineralogical studies of bottom ash and from the remediation of contaminated soil, where iron is used as an amendment. In this study, zero valent iron (Fe(0)) was added prior to accelerated carbonation in order to increase the number of adsorption sites for metals and thereby reduce leaching. Batch, column and pHstat leaching tests were performed and the leaching behaviour was evaluated with multivariate data analysis. It showed that leaching changed distinctly after the tested treatments, in particular after the combined treatment. Especially, the leaching of Cr and Cu clearly decreased as a result of accelerated carbonation. The combination of accelerated carbonation with Fe(0) addition reduced the leaching of Cr and Cu even further and reduced also the leaching of Mo, Zn, Pb and Cd compared to untreated BA. Compared with only accelerated carbonation, the Fe(0) addition significantly reduced the leaching of Cr, Cu and Mo. The effects of Fe(0) addition can be related to binding of the studied elements to newly formed iron oxides. The effects of Fe(0) addition were often more distinct at pH values between 7 and 9, which indicates that a single treatment with only Fe addition would be less effective and a combined treatment is recommended. The pHstat results showed that accelerated carbonation in combination with Fe(0)(0) addition widens the pH range for low solubility of about one unit for several of the studied elements. This indicates that pre-treating the bottom ash with a combination of accelerated carbonation and Fe(0) addition makes the leaching properties of the ash less sensitive to pH changes that may occur during reuse. All in all, the addition of Fe(0) in combination with carbonation could be an effective pre-treatment method for decreasing the mobility of potentially harmful components in bottom ash. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Evaluating the influence of National Research Council levels of copper, iron, manganese, and zinc using organic (Bioplex) minerals on resulting tissue mineral concentrations, metallothionein, and liver antioxidant enzymes in grower-finisher swine diets.

PubMed

Gowanlock, D W; Mahan, D C; Jolliff, J S; Hill, G M

2015-03-01

Graded levels of a trace mineral premix containing an organic (Bioplex) source of Cu, Fe, Mn, and Zn was evaluated with additional treatments containing organic Zn or Fe. Grower-finisher pigs were fed from 25 to 115 kg BW. The number of pigs in the experiment, the breeding/genetics of the pigs, the management, and the average age of the pigs were previously reported. The experiment was conducted as a randomized complete block design in 7 replicates. Treatments were 1) basal diet without supplemental Cu, Fe, Mn, and Zn; 2) basal diet + 2.5 mg/kg Cu, 50 mg/kg Fe, 1.5 mg/kg Mn, and 40 mg/kg Zn (50% NRC); 3) basal diet + 5 mg/kg Cu, 100 mg/kg Fe, 3 mg/kg Mn, and 80 mg/kg Zn (100% NRC); 4) basal diet + 25 mg Zn/kg; 5) basal diet + 50 mg Zn/kg; and 6) basal diet + 50 mg Fe/kg. Selenium and I were added to all diets at 0.3 and 0.14 mg/kg, respectively. Diets were composed of corn-soybean meal, dicalcium phosphate, and limestone with phytase added to enhance mineral availability. Three pigs per pen were bled at 55, 80, and 115 kg BW and plasma was analyzed for microminerals. When the average replicate BW was 115 kg, 3 pigs per pen of an equal gender ratio were killed. The liver, kidney, and heart were removed and analyzed for microminerals. Liver, duodenum, and jejunal metallothionein and the antioxidant enzymes in the liver containing these microminerals were determined. The results demonstrated that plasma minerals were unaffected at the 3 BW intervals. Liver and duodenum metallothionein protein were greater ( < 0.05) as dietary micromineral levels increased but jejunum metallothionein did not change as microminerals increased. The activity of Cu/Zn superoxide dismutase (SOD) was not affected as the levels of the micromineral increased, whereas the activity of Mn SOD increased slightly ( < 0.05) to the 50% NRC treatment level. Liver Zn (relative and total) increased ( < 0.05) as dietary micromineral levels increased and also when Zn was added singly to the diet. Liver, kidney, and heart Cu and Mn concentrations were similar at the various micromineral levels. The activities of liver enzymes containing graded levels of Zn were not affected by dietary microminerals at 115 kg BW. These results indicate that the supplemental levels of Cu, Fe, and Mn were not necessary for grower-finisher pigs and that these innate microminerals in a corn-soybean meal diet were adequate, whereas a need for supplemental Zn was demonstrated.

Isolation and reconstitution of iron- and manganese-containing superoxide dismutases from Bacteroides thetaiotaomicron.

PubMed Central

Pennington, C D; Gregory, E M

1986-01-01

Superoxide dismutase (SOD) from extracts of anaerobically maintained Bacteroides thetaiotaomicron was a dimer of equally sized 23,000-molecular-weight monomers joined noncovalently. A preparation with a specific activity of 1,200 U/mg contained 1.1 g-atom of Fe, 0.6 g-atom of Zn, and less than 0.05 g-atom of Mn per mol of dimer. The apoprotein, prepared by dialysis of iron-SOD in 5 M guanidinium chloride-20 mM 8-hydroxyquinoline, had no superoxide-scavenging activity when renatured without exogenous metal. Enzymatic activity was restored to the denatured apoprotein by dialysis against either 1 mM Fe(NH4)2 or 1 mM MnCl2 in 20 mM Tris (pH 7.0). The Fe-reconstituted enzyme and the native enzyme were inhibited approximately 50% by 0.2 mM NaN3, whereas the Mn-reconstituted enzyme was inhibited 60% by 10 mM NaN3. Aeration of the anaerobic cells resulted in a fourfold induction of an azide-resistant SOD. The enzyme (43,000 molecular weight) isolated from aerated cells was a dimer of equally sized subunits. The metal content was 1.0 g-atom of Mn, 0.55 g-atom of Fe, and 0.3 g-atom of Zn per mol of dimer. Enzymatic activity of the denatured apoprotein from this enzyme was also restored on addition of either iron or manganese. The constitutive Fe-SOD and the O2-induced Mn-SOD, tested alone and in combination, migrated identically on acrylamide gels, had similar amino acid compositions, and had alanine as the sole N-terminal amino acid. These data are consistent with the synthesis of a single apoprotein in either anaerobically maintained or oxygenated cells. We have observed a similar phenomenon with SOD from Bacteroides fragilis (E. M. Gregory, Arch. Biochem. Biophys. 238:83-89, 1985). PMID:3700336

Trace Element Status (Zinc, Copper, Selenium, Iron, Manganese) in Patients with Long-Term Home Parenteral Nutrition.

PubMed

Dastych, Milan; Šenkyřík, Michal; Dastych, Milan; Novák, František; Wohl, Petr; Maňák, Jan; Kohout, Pavel

2016-01-01

The objective of the present study was to determine concentrations of zinc (Zn), copper (Cu), iron (Fe), selenium (Se) in blood plasma and manganese (Mn) in the whole blood in patients with long-term home parenteral nutrition (HPN) in comparison to the control group. We examined 68 patients (16 men and 52 women) aged from 28 to 68 years on a long-term HPN lasting from 4 to 96 months. The short bowel syndrome was an indication for HPN. The daily doses of Zn, Cu, Fe, Se and Mn in the last 3 months were determined. No significant differences in blood plasma were found for Zn, Cu and Fe in patients with HPN and in the control group (p > 0.05). The concentration of Mn in whole blood was significantly increased in HPN patients (p < 0.0001), while Se concentration in these patients was significantly decreased (p < 0.005). The concentration of Mn in the whole blood of 16 patients with cholestasis was significantly increased compared to the patients without cholestasis (p < 0.001). The Cu concentration was increased with no statistical significance. In long-term HPN, the status of trace elements in the patients has to be continually monitored and the daily substitution doses of these elements have to be flexibly adjusted. Dosing schedule needs to be adjusted especially in cases of cholestatic hepatopathy. A discussion about the optimal daily dose of Mn in patients on HPN is appropriate. For clinical practice, the availability of a substitution mixture of trace elements lacking Mn would be advantageous. © 2016 S. Karger AG, Basel.

Milk protein composition and stability changes affected by iron in water sources.

PubMed

Wang, Aili; Duncan, Susan E; Knowlton, Katharine F; Ray, William K; Dietrich, Andrea M

2016-06-01

Water makes up more than 80% of the total weight of milk. However, the influence of water chemistry on the milk proteome has not been extensively studied. The objective was to evaluate interaction of water-sourced iron (low, medium, and high levels) on milk proteome and implications on milk oxidative state and mineral content. Protein composition, oxidative stability, and mineral composition of milk were investigated under conditions of iron ingestion through bovine drinking water (infused) as well as direct iron addition to commercial milk in 2 studies. Four ruminally cannulated cows each received aqueous infusions (based on water consumption of 100L) of 0, 2, 5, and 12.5mg/L Fe(2+) as ferrous lactate, resulting in doses of 0, 200, 500 or 1,250mg of Fe/d, in a 4×4Latin square design for a 14-d period. For comparison, ferrous sulfate solution was directly added into commercial retail milk at the same concentrations: control (0mg of Fe/L), low (2mg of Fe/L), medium (5mg of Fe/L), and high (12.5mg of Fe/L). Two-dimensional electrophoresis coupled with matrix-assisted laser desorption/ionization-tandem time-of-flight (MALDI-TOF/TOF) high-resolution tandem mass spectrometry analysis was applied to characterize milk protein composition. Oxidative stability of milk was evaluated by the thiobarbituric acid reactive substances (TBARS) assay for malondialdehyde, and mineral content was measured by inductively coupled plasma mass spectrometry. For milk from both abomasal infusion of ferrous lactate and direct addition of ferrous sulfate, an iron concentration as low as 2mg of Fe/L was able to cause oxidative stress in dairy cattle and infused milk, respectively. Abomasal infusion affected both caseins and whey proteins in the milk, whereas direct addition mainly influenced caseins. Although abomasal iron infusion did not significantly affect oxidation state and mineral balance (except iron), it induced oxidized off-flavor and partial degradation of whey proteins. Direct iron addition to milk led to lipid oxidation during storage at 4°C. Oxidation level was positively associated with the concentration of added iron. Minerals (Mg, P, Na, K, Ca, Zn) in milk were not affected by the added iron in milk. This study indicated that a small amount of iron contamination in bovine drinking water at the farm or incidental iron addition from potable water sources causes oxidation, affects milk protein composition and stability, and affects final milk quality. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Abundance, size distributions and trace-element binding of organic and iron-rich nanocolloids in Alaskan rivers, as revealed by field-flow fractionation and ICP-MS

NASA Astrophysics Data System (ADS)

Stolpe, Björn; Guo, Laodong; Shiller, Alan M.; Aiken, George R.

2013-03-01

Water samples were collected from six small rivers in the Yukon River basin in central Alaska to examine the role of colloids and organic matter in the transport of trace elements in Northern high latitude watersheds influenced by permafrost. Concentrations of dissolved organic carbon (DOC), selected elements (Al, Si, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Ba, Pb, U), and UV-absorbance spectra were measured in 0.45 μm filtered samples. 'Nanocolloidal size distributions' (0.5-40 nm, hydrodynamic diameter) of humic-type and chromophoric dissolved organic matter (CDOM), Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb were determined by on-line coupling of flow field-flow fractionation (FFF) to detectors including UV-absorbance, fluorescence, and ICP-MS. Total dissolved and nanocolloidal concentrations of the elements varied considerably between the rivers and between spring flood and late summer base flow. Data on specific UV-absorbance (SUVA), spectral slopes, and the nanocolloidal fraction of the UV-absorbance indicated a decrease in aromaticity and size of CDOM from spring flood to late summer. The nanocolloidal size distributions indicated the presence of different 'components' of nanocolloids. 'Fulvic-rich nanocolloids' had a hydrodynamic diameter of 0.5-3 nm throughout the sampling season; 'organic/iron-rich nanocolloids' occurred in the <8 nm size range during the spring flood; whereas 'iron-rich nanocolloids' formed a discrete 4-40 nm components during summer base flow. Mn, Co, Ni, Cu and Zn were distributed between the nanocolloid components depending on the stability constant of the metal (+II)-organic complexes, while stronger association of Cr to the iron-rich nanocolloids was attributed to the higher oxidation states of Cr (+III or +IV). Changes in total dissolved element concentrations, size and composition of CDOM, and occurrence and size of organic/iron and iron-rich nanocolloids were related to variations in their sources from either the upper organic-rich soil or the deeper mineral layer, depending on seasonal variations in hydrological flow patterns and permafrost dynamics.

Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

NASA Astrophysics Data System (ADS)

Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

2011-12-01

Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

New detections of arsenic, selenium, and other heavy elements in two metal-poor stars

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

Roederer, Ian U.; Schatz, Hendrik; Beers, Timothy C.

2014-08-10

We use the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope to obtain new high-quality spectra covering the 1900 ≤λ ≤ 2360 Å wavelength range for two metal-poor stars, HD 108317 and HD 128279. We derive abundances of Cu II, Zn II, As I, Se I, Mo II, and Cd II, which have not been detected previously in either star. Abundances derived for Ge I, Te I, Os II, and Pt I confirm those derived from lines at longer wavelengths. We also derive upper limits from the non-detection of W II, Hg II, Pb II, and Bi I.more » The mean [As/Fe] ratio derived from these two stars and five others in the literature is unchanged over the metallicity range –2.8 < [Fe/H] <–0.6, ([As/Fe]) = +0.28 ± 0.14 (σ = 0.36 dex). The mean [Se/Fe] ratio derived from these two stars and six others in the literature is also constant, ([Se/Fe]) = +0.16 ± 0.09 (σ = 0.26 dex). The As and Se abundances are enhanced relative to a simple extrapolation of the iron-peak abundances to higher masses, suggesting that this mass region (75 ≤A ≤ 82) may be the point at which a different nucleosynthetic mechanism begins to dominate the quasi-equilibrium α-rich freezeout of the iron peak. ([Cu II/Cu I]) = +0.56 ± 0.23 in HD 108317 and HD 128279, and we infer that lines of Cu I may not be formed in local thermodynamic equilibrium in these stars. The [Zn/Fe], [Mo/Fe], [Cd/Fe], and [Os/Fe] ratios are also derived from neutral and ionized species, and each ratio pair agrees within the mutual uncertainties, which range from 0.15 to 0.52 dex.« less

Immobilization of heavy metals in electroplating sludge by biochar and iron sulfide.

PubMed

Lyu, Honghong; Gong, Yanyan; Tang, Jingcshun; Huang, Yao; Wang, Qilin

2016-07-01

Electroplating sludge (ES) containing large quantities of heavy metals is regarded as a hazardous waste in China. This paper introduced a simple method of treating ES using environmentally friendly fixatives biochar (BC) and iron sulfide (FeS), respectively. After 3 days of treatment with FeS at a FeS-to-ES mass ratio of 1:5, the toxicity characteristic leaching procedure (TCLP)-based leachability of total Cr (TCr), Cu(II), Ni(II), Pb(II), and Zn(II) was decreased by 59.6, 100, 63.8, 73.5, and 90.5 %, respectively. After 5 days of treatment with BC at a BC-to-ES mass ratio of 1:2, the TCLP-based leachability was declined by 35.1, 30.6, 22.3, 23.1, and 22.4 %, respectively. Pseudo first-order kinetic model adequately simulated the sorption kinetic data. Structure and morphology analysis showed that adsorption, electrostatic attraction, surface complexation, and chemical precipitation were dominant mechanisms for heavy metals immobilization by BC, and that chemical precipitation (formation of metal sulfide and hydroxide precipitates), iron exchange (formation of CuFeS2), and surface complexation were mainly responsible for heavy metals removal by FeS. Economic costs of BC and FeS were 500 and 768 CNY/t, lower than that of Na2S (940 CNY/t). The results suggest that BC and FeS are effective, economic, and environmentally friendly fixatives for immobilization of heavy metals in ES before landfill disposal.

Paleozoic sedimentary rocks in the Red Dog Zn-Pb-Ag district and vicinity, western Brooks Range, Alaska: provenance, deposition, and metallogenic significance

USGS Publications Warehouse

Slack, John F.; Dumoulin, Julie A.; Schmidt, J.M.; Young, L.E.; Rombach, Cameron

2004-01-01

The distribution and composition of Paleozoic strata in the western Brooks Range may have played a fundamental role in Zn-Pb mineralization of the Red Dog district. In our model, deposition and early lithification of biogenic chert and bedded siliceous rocks in the upper part of the Kuna Formation served as a regional hydrologic seal, acting as a cap rock to heat and hydrothermal fluids during Late Mississippian base-metal mineralization. Equally important was the iron-poor composition of black shales of the Kuna Formation (i.e., low Fe/Ti ratios), which limited synsedimentary pyrite formation in precursor sediments, resulting in significant H2S production in pore waters through the interaction of aqueous sulfate with abundant organic matter. This H2S may have been critical to the subsurface deposition of the huge quantities of Zn and Pb in the district. On the basis of this model, we propose that low Fe/Ti and S/C ratios in black shale sequences are potential basin-scale exploration guides for giant sediment-hosted, stratiform Zn-Pb-Ag deposits.

Magnetic characteristics of M2FeV3O11 (M = Mg, Zn, Pb, Co, Ni) compounds

NASA Astrophysics Data System (ADS)

Groń, T.; Blonska-Tabero, A.; Filipek, E.; Stokłosa, Z.; Duda, H.; Sawicki, B.

2018-02-01

The unusual physical characteristics of the multicomponent oxide systems renewed the interest as the potential cathode materials in high-energy cells. Since the earlier magnetic characteristics were not entirely conclusive, we report the results of dc magnetic measurements including higher harmonics of ac magnetic susceptibility of the M2FeV3O11 (M = Mg, Zn, Pb, Co, Ni) compounds. Ferrimagnetic long-range and antiferromagnetic short-range interactions for all compounds under study at low temperatures as well as superparamagnetic-like behavior with the blocking temperature of 29 K and the freezing parameter of 0.013 were observed. These effects are discussed within the framework of superexchange and double exchange magnetic interactions as well as the mixed valence band of iron ions.

HUMAN SCALP HAIR: AN ENVIRONMENTAL EXPOSURE INDEX FOR TRACE ELEMENTS. III. SEVENTEEN TRACE ELEMENTS IN BIRMINGHAM, ALABAMA AND CHARLOTTE, NORTH CAROLINA (1972)

EPA Science Inventory

Seventeen trace elements - arsenic (As), barium (Ba), boron, (B), cadmium, (Cd), chromium (Cr), copper (Cu), Iron (Fe), lead (Pb), lithium (Li), manganese (Mn), mercury (Hg), nickel (Ni), selenium (Se), silver (Ag), tin (Sn), vanadium (V), and Zinc (Zn) - were measured in human s...

Dietary mineral supplies in Africa

PubMed Central

Joy, Edward J M; Ander, E Louise; Young, Scott D; Black, Colin R; Watts, Michael J; Chilimba, Allan D C; Chilima, Benson; Siyame, Edwin W P; Kalimbira, Alexander A; Hurst, Rachel; Fairweather-Tait, Susan J; Stein, Alexander J; Gibson, Rosalind S; White, Philip J; Broadley, Martin R

2014-01-01

Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using food supply and composition data, and consider the potential of food-based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) ‘cut-point’ approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population-weighted mean phytate supply is 2770 mg capita−1 day−1. Deficiency risks for Fe are lower than expected (5%). However, ‘cut-point’ approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high-phytate, low-animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting harvestplus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks. PMID:24524331

Effect of adsorbed metals ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer

USGS Publications Warehouse

Kent, D.B.; Davis, J.A.; Anderson, L.C.D.; Rea, B.A.; Coston, J.A.

2002-01-01

Adsorption, complexation, and dissolution reactions strongly influenced the transport of metal ions complexed with ethylenediaminetetraacetic acid (EDTA) in a predominantly quartz-sand aquifer during two tracer tests conducted under mildly reducing conditions at pH 5.8 to 6.1. In tracer test M89, EDTA complexes of zinc (Zn) and nickel (Ni), along with excess free EDTA, were injected such that the lower portion of the tracer cloud traveled through a region with adsorbed manganese (Mn) and the upper portion of the tracer cloud traveled through a region with adsorbed Zn. In tracer test S89, Ni- and Zn-EDTA complexes, along with excess EDTA complexed with calcium (Ca), were injected into a region with adsorbed Mn. The only discernable chemical reaction between Ni-EDTA and the sediments was a small degree of reversible adsorption leading to minor retardation. In the absence of adsorbed Zn, the injected Zn was displaced from EDTA complexes by iron(III) [Fe(III)] dissolved from the sediments. Displacement of Zn by Fe(III) on EDTA became increasingly thermodynamically favorable with decreasing total EDTA concentration. The reaction was slow compared to the time-scale of transport. Free EDTA rapidly dissolved aluminum (Al) from the sediments, which was subsequently displaced slowly by Fe. In the portion of tracer cloud M89 that traveled through the region contaminated with adsorbed Zn, little displacement of Zn complexed with EDTA was observed, and Al was rapidly displaced from EDTA by Zn desorbed from the sediments, in agreement with equilibrium calculations. In tracer test S89, desorption of Mn dominated over the more thermodynamically favorable dissolution of Al oxyhydroxides. Comparison with results from M89 suggests that dissolution of Al oxyhydroxides in coatings on these sediment grains by Ca-EDTA was rate-limited whereas that by free EDTA reached equilibrium on the time-scale of transport. Rates of desorption are much faster than rates of dissolution of Fe oxyhydroxides from sediment-grain surfaces and, therefore, adsorbed metal ions can strongly influence the speciation of ligands like EDTA in soils and sediments, especially over small temporal and spatial scales. Copyright ?? 2002 Elsevier Science Ltd.

The phase relations in the In 2O 3Fe 2ZnO 4ZnO system at 1350°C

NASA Astrophysics Data System (ADS)

Nakamura, Masaki; Kimizuka, Noboru; Mohri, Takahiko

1990-05-01

The phase relations in the In 2O 3Fe 2ZnO 4ZnO system at 1350°C are determined by means of a classical quenching method. There are a series of homologous solid solutions, In 1.28Fe 0.72O 3(ZnO)InFeO 3(ZnO), In 1.69Fe 0.31O 3(ZnO) 2InFeO 3(ZnO) 2In 0.85Fe 1.15O 3(ZnO) 2, In 2O 3(ZnO) 3InFeO 3(ZnO) 3In 0.78Fe 1.22O 3(ZnO) 3, In 2O 3(ZnO) 4InFeO 3(ZnO) 4In 0.62Fe 1.38O 3(ZnO) 4, In 2O 3(ZnO) 5InFeO 3(ZnO) 5In 0.67Fe 1.33O 3(ZnO) 5, In 2O 3(ZnO) 6InFeO 3(ZnO) 6In 0.60Fe 1.40O 3(ZnO) 6, In 2O 3(ZnO) 7InFeO 3(ZnO) 7In 0.51Fe 1.49O 3(ZnO) 7, In 2O 3(ZnO) 8InFeO 3(ZnO) 8In 1- xFe 1+ xO 3(ZnO) 8 (0.44 ≦ x ≦ 0.64), In 2O 3(ZnO) 9InFeO 3(ZnO) 9In 0.20Fe 1.80O 3(ZnO) 9, In 2O 3(ZnO) 10InFeO 3(ZnO) 10In 1- xFe 1+ xO 3(ZnO) 10 (0.74 ≦ x ≦ 0.89), In 2O 3(ZnO) 11InFeO 3(ZnO) 11In 1- xFe 1+ xO 3(ZnO) 11 (0.60 ≦ x < 1.00), and In 2O 3(ZnO) 13InFeO 3(ZnO) 13Fe 2O 3(ZnO) 13 having the layered structures with space group R overline3m (m = odd) or {P6 3}/{mmc} (m = even) for m in the InFeO 3(ZnO) m. We conclude that there are a series of homologous phases, (Fe 2O 3)(ZnO) m (m ≧ 12) , in the binary ZnOFe 2O 3 system. The lattice constants for these solid solutions are presented as a hexagonal crystal system. It is also concluded that the crystal structures for each solid solution consist of three kinds of layers which are stacked perpendicular to the c-axis in the hexagonal crystal system. In 1+ xFe 1- xO 3(ZnO) m (0 ≦ x ≦ 1) is composed of the InO 1.5, (In xFe 1- xZn)O 2.5, and ZnO layers, and In 1- xFe 1+ xO 3(ZnO) m (0 ≦ x ≦ 1) is composed of (In 1- xFe x)O 1.5, (FeZn)O 2.5, and ZnO layers, respectively. The solid solution range between Fe 2ZnO 4 and In xFe 2- xZnO 4 ( x = 0.40 ± 0.02) with a spinel structure is observed.

Studies on the growth and flowering of a short-day plant, Wolffia microscopica : II. Role of metal ions and chelates.

PubMed

Seth, P N; Venkataraman, R; Maheshwari, S C

1970-12-01

As found earlier, supply of EDTA was obligatory for both flowering and satisfactory vegetative growth in Wolffia microscopica. It is now shown that the metal affecting growth and flowering is most probably iron. Omission of Fe but not of Cu, Zn, Mn and B from the medium markedly affects vegetative growth. There exists also a strong interaction between EDTA and Fe, one being largely inactive in the absence of the other. When Fe-EDDHA is substituted for Fe-citrate and EDTA in the medium, no great effect is seen in vegetative growth, but flowering takes place even under continuous light. Studies with (59)Fe show that, in the medium containing Fe-EDDHA, Fe uptake is stimulated several-fold; this is apparently associated with the flowering condition.

Cold Extrusion but Not Coating Affects Iron Bioavailability from Fortified Rice in Young Women and Is Associated with Modifications in Starch Microstructure and Mineral Retention during Cooking.

PubMed

Hackl, Laura; Speich, Cornelia; Zeder, Christophe; Sánchez-Ferrer, Antoni; Adelmann, Horst; de Pee, Saskia; Tay, Fabian; Zimmermann, Michael B; Moretti, Diego

2017-12-01

Background: Rice can be fortified with the use of hot or cold extrusion or coating, but the nutritional qualities of the resulting rice grains have never been directly compared. Objective: Using fortified rice produced by coating or hot or cold extrusion, we compared 1 ) iron and zinc absorption with the use of stable isotopes, 2 ) iron and zinc retention during cooking, and 3 ) starch microstructure. Methods: We conducted 2 studies in young women: in study 1 [ n = 19; mean ± SD age: 26.2 ± 3.4 y; body mass index (BMI; in kg/m 2 ): 21.3 ± 1.6], we compared the fractional iron absorption (FAFe) from rice meals containing isotopically labeled ferric prophosphate ( 57 FePP), zinc oxide (ZnO), citric acid, and micronutrients fortified through hot extrusion (HER1) with rice meals fortified through cold extrusion containing 57 FePP, ZnO, citric acid, and micronutrients (CER); in study 2 ( n = 22; age: 24 ± 4 y; BMI: 21.2 ± 1.3), we compared FAFe and fractional zinc absorption (FAZn) from rice meals fortified through hot extrusion (HER2) compared with rice meals fortified through coating containing 57 FePP, ZnO, a citric acid and trisodium cirate mixture (CA/TSC), and micronutrients (COR) relative to rice meals extrinsically fortified with ferrous sulfate (reference). Rice types HER1 and CER contained citric acid, whereas types HER2 and COR contained CA/TSC. We assessed retention during standardized cooking experiments and characterized the rice starch microstructure. Results: FAFe (95% CI) was greater from CER [2.2% (1.4%, 3.4%)] than from HER1 [1.2% (0.7%, 2.0%)] ( P = 0.036). There was no difference in FAFe between HER2 [5.1% (3.7%, 7.1%)] and COR [4.0% (2.9%, 5.4%)] ( P = 0.14), but FAFe from COR was lower than that from the reference meal [6.6% (4.9%, 9.0%)] ( P = 0.003), and the geometric mean FAZn (95% CI) did not differ between HER2 [9.5% (7.9%, 11.6%)] and COR [9.6% (8.7%, 10.7%)] ( P = 0.92). Cooking in a rice-to-water ratio of 1:2 resulted in iron and zinc retentions >80%, and cooking in excess water did not affect iron retention from hot-extruded rice but caused iron losses of 25% from CER and COR. Distinct variations in starch microstructure were found in CER and HER1. Conclusions: Iron absorption was 64% higher from CER than from hot-extruded rice, with no difference between COR compared with hot-extruded rice. Lower extrusion temperatures may generate a more readily digestible starch structure, allowing for greater iron release in vivo but lower mineral retention during cooking. This trial was registered at clinicaltrials.gov as NCT02176759. © 2017 American Society for Nutrition.

High Precision Iron Isotope Compositions in Components From the Allende CV3 Meteorite by MC-ICP-MS

NASA Astrophysics Data System (ADS)

Mullane, E.; Russell, S. S.; Weiss, D.; Mason, T. F.; Gounelle, M.

2001-12-01

Four chondrules and one matrix sample of Allende were examined for Fe-isotope frac-tionation, using multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). Iron is the most volatile major constituent of chondrules and a recent study [1] suggested that solar system Fe was initially isotopically homogeneous. Thus, any isotopic variation is likely due to mass fractionation during nebular process-ing. The chondrule samples were split. One portion was subject to a standard acid dis-solution whilst the other was polished, ena-bling textural and compositional characteri-zation. Fe, Cu and Zn are separated from the remaining matrix elements [2], removing potential interfering ions from the solution. 100 % elemental recovery (within error) is achieved, ensuring that chromatographic fractionation does not occur [2]. Hydrogen is bled into the collision cell, minimising Ar polyatomic species interferences. Typical precisions of 0.1‰ (2σ ) for 54Fe/56Fe ratios are achieved for 75 replicates. Instrumental mass bias is assessed using (1) sample-standard brack-eting and (2) doping with Cu. A variation of 0.8‰ /amu is observed, which is approximately 18 times the analyti-cal uncertainty at the 2σ level. Our high precision data show that: (1) Allende chondrules and matrix exhibit clear isotopic variation in iron. (2) δ 54Fe val-ues appear to be correlated to the bulk FeO content, with the more iron rich samples enriched in the lighter 54Fe isotope. (3) δ 54Fe values appear to be unre-lated to texture, and consequently to the temperature of chondrule formation. Bulk Fe-content may be a proxy for the amount of volatilisation experienced, and volatilisation of Fe in chondrule precursor material has resulted in a residue of the heavier Fe isotopes. Chondrules are known to have often experienced several heating events, and their texture primarily reflects the nature of the last event. Thus, the lack of correlation between the δ 54Fe value and chondrule texture suggests that Fe-isotope composi-tion was derived from chondrule precursor material. [1] Zhu et al. (2001) Nature 412, p.311 [2] Mullane et al. (2001) LPS XXXII, No.1545.

NASA Astrophysics Data System (ADS)

Yao, Jinhuan; Li, Yanwei; Li, Xuanhai; Le, Shiru

2014-07-01

The geometric structure, electronic structure, and stability of In-substituted ZnFe2O4 (Zn7InFe16O32 and Zn8Fe15InO32) are investigated by the density functional theory at generalized gradient approximation level. Compared with the perfect ZnFe2O4 (Zn8Fe16O32), the unit cell volume of In-substituted ZnFe2O4 increases and the structure deforms slightly. The formation energy of In substitution for Zn is smaller than that of In substitution for Fe, indicating that Zn7InFe16O32 is easier to be formed than Zn8Fe15InO32. In substitution changes the properties of ZnFe2O4 from semiconducting character to metallic character. For ZnFe2O4 and In-substituted ZnFe2O4, the strength of O-Zn bond is stronger than O-Fe bond and both of them have a covalent bond character. The strength of O-In bond is similar to that of O-Zn bond in Zn7InFe16O32, but weaker than O-Fe in Zn8Fe15InO32. In substitution for Zn causes the strength of O-Fe bonds around In atom to weaken. In substitution for Fe causes the strength of O-Zn bonds around In atom to weaken obviously, while the strength of O-Fe bonds strengthen slightly.

Highly selective colorimetric and electrochemical sensing of iron (III) using Nile red functionalized graphene film.

PubMed

Sadak, Omer; Sundramoorthy, Ashok K; Gunasekaran, Sundaram

2017-03-15

We report a highly selective method for identification and detection of iron (III) (ferric iron, Fe 3+ ) using Nile red (NR) as a complexing agent. Fe 3+ preferentially binds with NR in dimethylformamide (DMF)/water (1:1) solution over other cations such as Fe 2+ , Cu 2+ , Pb 2+ , Hg 2+ , Mn 2+ , Ni 2+ , Zn 2+ , Co 2+ and Cd 2+ at room temperature. In the presence of Fe 3+ , the color of NR solution changes from purple to dark brown, which is detectable with bare eyes. Using UV-vis spectroscopy, we could measure the amount of Fe 3+ in the sample solution by monitoring changes in absorption from 540 to 580nm; the linear range and the limit of detection are 30-1000µM and 24.9µM, respectively. Taking advantage of the NR selectivity, we treated partially oxidized graphene sheets (po-Gr) with NR to obtain po-Gr-NR dispersion by ultrasonication. The NR-treated po-Gr flakes (po-Gr-NR) were characterized by UV-vis, FT-IR, and Raman spectroscopies and FE-SEM, which indicated attachment of NR on po-Gr sheets. The po-Gr-NR hybrid film deposited glassy carbon electrode (po-Gr-NR/GCE) served as the Fe 3+ sensor. Differential pulse voltammetry was used to investigate the detection of Fe 3+ in 0.05M HCl+0.05M KCl solution. The linear range and the limit of detection of Fe 3+ were from 37.5nM to 21.53µM and 18.7nM, respectively. Furthermore, this sensor was successfully used to measure Fe 3+ content in red wine samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Estimation of the bioaccessibility and bioavailability of Fe, Mn, Cu, and Zn in Chinese vegetables using the in vitro digestion/Caco-2 cell model: the influence of gut microbiota.

PubMed

Cai, Xiaolin; Chen, Xiaochen; Yin, Naiyi; Du, Huili; Sun, Guoxin; Wang, Lihong; Xu, Yudong; Chen, Yuqing; Cui, Yanshan

2017-12-13

The influence of the human gut microbiota on the bioaccessibility and bioavailability of trace elements in vegetables has barely been studied. An in vitro digestion model combining the physiologically based extraction test (PBET) and the Simulator of Human Intestinal Microbial Ecosystem (SHIME) was applied. Results showed that the gut microbiota increased the bioaccessibility of iron (Fe) in ten test vegetables by 1.3-1.8 times, but reduced the bioaccessibility of manganese (Mn), copper (Cu), and zinc (Zn) in vegetables in the colon phase by 3.7% to 89.6%, 24.8% to 100.0%, and 59.9% to 100.0%, respectively. Using the Caco-2 cell model to simulate the human absorption process, the bioavailable contents and the bioavailability of the trace elements were further determined. Swamp cabbage was the best source of Fe and Cu; spinach and lettuce provided the highest amounts of bioavailable Mn and Zn, respectively. Referring to the daily reference intakes of trace elements, the obtained data provide a scientific basis for both reasonable ingestion of vegetables in diets and diversification of diets.

Distribution of copper, iron, and zinc in biological samples (scalp hair, serum, blood, and urine) of Pakistani viral hepatitis (A-E) patients and controls.

PubMed

Kolachi, Nida Fatima; Kazi, Tasneem Gul; Afridi, Hassan Imran; Kazi, Naveed; Kandhro, Ghulam Abbas; Shah, Abdul Qadir; Baig, Jameel Ahmed; Wadhwa, Sham Kumar; Khan, Sumaira; Shah, Faheem; Jamali, Mohammad Khan; Arain, Mohammad Balal

2011-10-01

The aim of the present study was to compare the level of copper (Cu), iron (Fe) and zinc (Zn) in biological samples (serum, blood, urine, and scalp hair) of patients suffering from different viral hepatitis (A, B, C, D, and E; n = 521) of both gender age ranged 31-45 years. For comparative study, 255 age-matched control subjects, of both genders residing in the same city were selected as referents. The elements in the biological samples were analyzed by flame atomic absorption spectrophotometry, prior to microwave-assisted acid digestion. The validity and accuracy of the methodology was checked by using certified reference materials (CRMs) and with those values obtained by conventional wet acid digestion method on same CRMs. The results of this study showed that the mean values of Cu and Fe were higher in blood, sera, and scalp hair samples of hepatitis patients, while Zn level was found to be lower than age-matched control subjects. The urinary levels of these elements were found to be higher in the hepatitis patients than in the age-matched healthy controls (p < 0.05). These results are consistent with literature-reported data, confirming that the deficiency of zinc and hepatic iron and copper overload can directly cause lipid peroxidation and eventually hepatic damage.

Compromised zinc status of experimental rats as a consequence of prolonged iron & calcium supplementation.

PubMed

Jayalakshmi, S; Platel, Kalpana

2016-02-01

Iron supplementation is usually given to pregnant and lactating women who may also have marginal deficiency of zinc. The negative impact of supplemental iron and calcium on zinc status is a cause of concern. The present investigation was undertaken to examine the effect of inclusion of iron and calcium in the diet at supplementary levels on zinc status of experimental rats. Groups of experimental rats were maintained on diets supplemented with iron (Molar ratio - Zn:Fe 1:30) and calcium (Molar ratio - Zn:Ca 1:667) both individually and in combination for six weeks. Zinc status of these rats was assessed by determining zinc concentration in circulation and in organs, and the activities of zinc containing enzymes in serum and liver. The zinc status of experimental rats receiving supplemental levels of iron and calcium was significantly compromised. Zinc concentration in serum, kidney, spleen and liver was reduced significantly by both these minerals. Six weeks of supplementation of iron and calcium individually, significantly reduced the activity of liver and serum superoxide dismutase and alkaline phosphatase. Activity of liver alcohol dehydrogenase was lowered in calcium supplemented group and in calcium + iron supplemented group, while that of carbonic anhydrase was significantly reduced by iron, calcium and their combination. Supplemental levels of iron and calcium, both individually and in combination, significantly compromised the zinc status of experimental rats. This negative effect of these two minerals was more prominent when these were supplemented for a period of six weeks.

Assessment of the effects of glutamic acid decarboxylase antibodies and trace elements on cognitive performance in older adults.

PubMed

Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas S

2015-01-01

Homeostatic imbalance of trace elements such as iron (Fe), copper (Cu), and zinc (Zn) demonstrated adverse effects on brain function among older adults. The present study aimed to investigate the effects of trace elements and the presence of anti-glutamic acid decarboxylase antibodies (GADAs) in human cognitive abilities among healthy older adults. A total of 100 healthy subjects (65 males, 35 females; age range; 64-96 years) were recruited for this study. Based on Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) score, the participants were classified according to cognitive performance into normal (n=45), moderate (n=30), and severe (n=25). Cognitive functioning, leisure-time physical activity (LTPA), serum trace elements - Fe, Cu, Zn, Zn/Cu, and GADAs were assessed using LOTCA battery, pre-validated physical activity (PA) questionnaire, atomic absorption, and immunoassay techniques, respectively. Approximately 45% of the study population (n=45) had normal distribution of cognitive function and 55% of the study population (n=55) had abnormal cognitive function; they were classified into moderate (score 62-92) and severe (score 31-62). There was a significant reduction in the level of Zn and Zn/Cu ratio along with an increase in the level of Fe, Cu, and anti-GADAs in subjects of severe (P=0.01) and moderate (P=0.01) cognitive performance. LOTCA-cognitive scores correlated positively with sex, HbA(1c), Fe, Cu, Zn, and Zn/Cu ratio, and negatively with age, PA, body mass index, and anti-GADAs. Significant inter-correlation was reported between serum trace element concentrations and anti-GADAs which suggest producing a cognitive decline via oxidative and neural damage mechanism. This study found significant associations among trace elements, anti-GADAs, and cognitive function in older adults. The homeostatic balance of trace elements should be recommended among older adults for better cognitive performance.

The use of nuclear muprobe techniques to study the chemistry of lacustrine sediments and particles

NASA Astrophysics Data System (ADS)

Grime, G. W.; Davison, W.

1993-05-01

The Oxford SPM has been used in two novel studies of lake chemistry: (a) The distribution of dissolved iron in sediment pore waters close to the sediment/water interface has been measured using the novel technique of diffusive equilibration in a thin film (DET). In this technique, which has a spatial resolution of < 1 mm, much less than that of competing techniques (1 cm), a thin layer of polyacrylamide gel is inserted into the sediment and after the rapid equilibration with the pore water, the gel is dried and fixed. The distribution of trace elements can then be measured using mubeam PIXE. Preliminary results have shown for the first time a subsurface maximum of Fe consistent with current theories of Fe dynamics. This paper presents some results obtained using the technique and discusses the limits on resolution and sensitivity, (b) Individual suspended lake particles (predominantly iron oxides and sulphides) have been analysed using point mubeam RBS and PIXE. Of particular interest in this study is the oxidation state of iron rich particles, so RBS with a 1 μm beam was used to determine the Fe: O stoichiometry of single particles. The particles were filtered from a depth of 14 m in Esthwaite Water in the English Lake District and handled in anoxic conditions until evacuation in the SPM sample chamber. Two distinct compositions of iron oxide were determined in clusters of about 5 μm diameter. Analysis by PIXE revealed that FeS was uniformly distributed in the particulate material and that it also contained elevated levels of Cu and Zn. This study was the first to demonstrate directly that discrete clusters of iron oxides are present in black particulate material which is commonly considered to comprise iron sulphides.

Determination of trace elements in dolomite and gypsum by atomic absorption spectrometry: overcoming the matrix interference by flotation separation

NASA Astrophysics Data System (ADS)

Stafilov, Trajče; Zendelovska, Dragica; Pavlovska, Gorica; Čundeva, Katarina

2002-05-01

The interferences of Ca and Mg as matrix elements in dolomite and gypsum on Ag, Cd, Cr, Mn, Tl and Zn absorbances during their electrothermal atomic absorption spectrometric (ETAAS) determination are investigated. The results reveal that Ca and Mg do not interfere on Zn and Mn, tend to decrease absorbances of Ag, Cd and Cr, while Tl suffers the most significant influence. A flotation separation method is proposed to eliminate matrix interferences. Hydrated iron(III) oxide, Fe 2O 3· xH 2O, and iron(III) hexamethylenedithiocarbamate, Fe(HMDTC) 3, are applied as flotation collectors. The influence of hydrophobic dithiocarbamate anion, HMDTC, on flotation recoveries of each analyte is studied. The most suitable concentrations of dolomite and gypsum solutions for flotation are determined. To avoid flotation suppression due to the reaction of Ca 2+ and Mg 2+ with surfactant ions, a fit foaming agent was selected. The elements present in dolomite and gypsum as traces have been analyzed by ETAAS. Their ETAAS limits of detection following flotation are found to be 0.021 μg·g -1 for Ag, 0.019 μg·g -1 for Cd, 0.014 μg·g -1 for Cr and 0.11 μg·g -1 for Tl. The determination of Mn and Zn can be performed by flame AAS (FAAS). The limit of detection for Mn is 1.5 μg·g -1, while for Zn 0.8 μg·g -1.

Evolution of magnetization in epitaxial Zn1‑x Fe x O z thin films (0  ⩽  x  ⩽  0.66) grown by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Brachwitz, Kerstin; Böntgen, Tammo; Lenzner, Jörg; Ghosh, Kartik; Lorenz, Michael; Grundmann, Marius

2018-06-01

We demonstrate the development of phases in Zn1‑xFexOz thin films with 0  ⩽  x  ⩽  0.66, i.e. the end point phases are semiconducting ZnO for x  =  0, and ferrimagnetic zinc ferrite (ZnFe2O4) for x  =  0.66. With increasing x, the x-ray scattering intensity of the structural ZnO wurtzite phase decreases while that of the (1 1 1)-oriented ZnFe2O4 spinel phase increases. For x  >  0.4, single phase spinel layers are obtained. The enhanced formation of the spinel phase is supported by deviations from the usually expected stoichiometric transfer of chemical composition from target to thin film in pulsed laser deposition. We find that all mixed film samples show an excess of iron in relation to the target composition, independent of the growth pressure. The saturation magnetization of the samples increases with x for 0  ⩽  x  ⩽  0.66 and shows a ferrimagnetic behavior. The temperature dependence of magnetization points to Curie temperatures well above 400 K for x  ⩾  0.4. With that, the precise tuning of magnetic performance of the thin layers is possible, yielding a design degree of freedom for application-related requirements.

Zeolitic imidazolate framework-8-derived N-doped porous carbon coated olive-shaped FeOx nanoparticles for lithium storage

NASA Astrophysics Data System (ADS)

Gan, Qingmeng; Zhao, Kuangmin; He, Zhen; Liu, Suqin; Li, Aikui

2018-04-01

We propose a new strategy to uniformly coat zeolitic imidazolate framework-8 (ZIF-8) on iron oxides containing no Zn to obtain an α-Fe2O3@ZIF-8 composite. After carbonization, the α-Fe2O3@ZIF-8 transforms into iron oxides@N-doped porous carbon (FeOx@NC). The uniform N-doped porous carbon layer gives rise to a superior electrical conductivity, highly-increased specific BET surface area (179.2 m2 g-1), and abundant mesopores for the FeOx@NC composite. When served as the LIB anode, the FeOx@NC shows a high reversible capacity (of 1064 mA h g-1 at 200 mA g-1), excellent rate performance (of 198.1 mA h g-1 at 10000 mA g-1) as well as brilliant long-term cyclability (with a capacity retention of 93.3% after 800 cycles), which are much better than those of the FeOx@C and pristine FeOx anodes. Specifically, the Li-ion intercalation pseudocapacitive behavior of the FeOx@NC anode is improved by this N-doped porous carbon coating, which is beneficial for rapid Li-ion insertion/extraction processes. The excellent electrochemical performance of FeOx@NC should be ascribed to the increased electrolyte penetration areas, improved electrical conductivity, boosted lithium storage kinetics, and shortened Li-ion transport length.

The influence of earthworms on the mobility of microelements in soil and their availability for plants

NASA Astrophysics Data System (ADS)

Bityutskii, N. P.; Kaidun, P. I.

2008-12-01

The influence of earthworms ( Aporrectodea caliginosa, Lumbricus rubellus, L. terrestris, and Eisenia fetida) on the mobility of microelements and their availability for plants was studied. The contents of water-soluble Fe and Mn compounds extracted from the coprolites were 5-10 times higher than that in the soil (enriched in calcium carbonate and dried) consumed by the earthworms. This digestion-induced effect became higher with the age of the coprolites (up to 9 days) and took place under their alkalization. In the excreta (surface + enteric) of earthworms, the Fe concentration exceeded those of Mn and Zn by many times. Iron and manganese were mostly concentrated (>80% and >60%, respectively) in the organic part of the excrements. In the tests with hydroponics, the excreta were found to be a source of iron compounds available for plants that were similar to Fe2(SO4)3 or Fe-citrate by their physiological effect in the case when the Fe concentration in the excretions was above 0.7 μM. However, the single application of excreta of different earthworm species into the CaCO3 enriched soil did not significantly affect the plant (cucumber) nutrition. The analysis of the transport of microelements with xylem sap showed that this fact appeared to be due to the absence of an Fe deficit in the cucumber plants because of their high capability for the absorption of weakly soluble iron compounds.

Carbon-Coated Core-Shell Fe-Cu Nanoparticles as Highly Active and Durable Electrocatalysts for a Zn-Air Battery.

PubMed

Nam, Gyutae; Park, Joohyuk; Choi, Min; Oh, Pilgun; Park, Suhyeon; Kim, Min Gyu; Park, Noejung; Cho, Jaephil; Lee, Jang-Soo

2015-06-23

Understanding the interaction between a catalyst and oxygen has been a key step in designing better electrocatalysts for the oxygen reduction reaction (ORR) as well as applying them in metal-air batteries and fuel cells. Alloying has been studied to finely tune the catalysts' electronic structures to afford proper binding affinities for oxygen. Herein, we synthesized a noble-metal-free and nanosized transition metal CuFe alloy encapsulated with a graphitic carbon shell as a highly efficient and durable electrocatalyst for the ORR in alkaline solution. Theoretical models and experimental results demonstrated that the CuFe alloy has a more moderate binding strength for oxygen molecules as well as the final product, OH(-), thus facilitating the oxygen reduction process. Furthermore, the nitrogen-doped graphitic carbon-coated layer, formed catalytically under the influence of iron, affords enhanced charge transfer during the oxygen reduction process and superior durability. These benefits were successfully confirmed by realizing the catalyst application in a mechanically rechargeable Zn-air battery.

High-strain-rate superplasticity of the Al-Zn-Mg-Cu alloys with Fe and Ni additions

NASA Astrophysics Data System (ADS)

Kotov, A. D.; Mikhaylovskaya, A. V.; Borisov, A. A.; Yakovtseva, O. A.; Portnoy, V. K.

2017-09-01

During high-strain-rate superplastic deformation, superplasticity indices, and the microstructure of two Al-Zn-Mg-Cu-Zr alloys with additions of nickel and iron, which contain equal volume fractions of eutectic particles of Al3Ni or Al9FeNi, have been compared. It has been shown that the alloys exhibit superplasticity with 300-800% elongations at the strain rates of 1 × 10-2-1 × 10-1 s-1. The differences in the kinetics of alloy recrystallization in the course of heating and deformation at different temperatures and rates of the superplastic deformation, which are related to the various parameters of the particles of the eutectic phases, have been found. At strain rates higher than 4 × 10-2, in the alloy with Fe and Ni, a partially nonrecrystallized structure is retained up to material failure and, in the alloy with Ni, a completely recrystallized structure is formed at rates of up to 1 × 10-1 s-1.

Distribution and speciation of trace elements in iron and manganese oxide cave deposits

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

Frierdich, Andrew J.; Catalano, Jeffrey G.

2012-10-24

Fe and Mn oxide minerals control the distribution and speciation of heavy metals and trace elements in soils and aquatic systems through chemical mechanisms involving adsorption, incorporation, and electron transfer. The Pautler Cave System in Southwest Illinois, an analog to other temperate carbonate-hosted karst systems, contains Fe and Mn oxide minerals that form in multiple depositional environments and have high concentrations of associated trace elements. Synchrotron-based micro-scanning X-ray fluorescence ({mu}-SXRF) shows unique spatial distributions of Fe, Mn, and trace elements in mineral samples. Profile maps of Mn oxide cave stream pebble coatings show Fe- and As-rich laminations, indicating dynamic redoxmore » conditions in the cave stream. {mu}-SXRF maps demonstrate that Ni, Cu, and Zn correlate primarily with Mn whereas As correlates with both Mn and Fe; As is more enriched in the Fe phase. Zn is concentrated in the periphery of Mn oxide stream pebble coatings, and may be an indication of recent anthropogenic surface activity. X-ray absorption fine structure spectroscopy measurements reveal that As(V) occurs as surface complexes on Mn and Fe oxides whereas Zn(II) associated with Mn oxides is adsorbed to the basal planes of phyllomanganates in a tetrahedral coordination. Co(III) and Se(IV) are also observed to be associated with Mn oxides. The observation of Fe, Mn, and trace element banding in Mn oxide cave stream pebble coatings suggests that these materials are sensitive to and document aqueous redox conditions, similar to ferromanganese nodules in soils and in marine and freshwater sediments. Furthermore, speciation and distribution measurements indicate that these minerals scavenge trace elements and limit the transport of micronutrients and contaminants in karst aquifer systems while also potentially recording changes in anthropogenic surface activity and land-use.« less

Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

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

Lin, Y.W.; Robinson, H.; Yeung, N.

2010-07-28

A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN?-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site. EPRmore » studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.« less

Nutritional Impacts of Saskatchewan Grown Lentils (Lens culinaris L) Feeding on Samples of Healthy and Clinical Children in Sri Lanka

USDA-ARS?s Scientific Manuscript database

Canadian grown Lentil is a rich source of micronutrients. It has high levels of selenium (Se), iron (Fe), zinc (Zn), folic acid and carotenes (Thavarajah, et al., 2007; 2008, 2009, Wilmot et al., 2009). In addition, our latest finding shows that Canadian lentil has naturally low levels of antinutri...

Silicon induced Fe deficiency affects Fe, Mn, Cu and Zn distribution in rice (Oryza sativa L.) growth in calcareous conditions.

PubMed

Carrasco-Gil, Sandra; Rodríguez-Menéndez, Sara; Fernández, Beatriz; Pereiro, Rosario; de la Fuente, Vicenta; Hernandez-Apaolaza, Lourdes

2018-04-01

A protective effect by silicon in the amelioration of iron chlorosis has recently been proved for Strategy 1 species, at acidic pH. However in calcareous conditions, the Si effect on Fe acquisition and distribution is still unknown. In this work, the effect of Si on Fe, Mn, Cu and Zn distribution was studied in rice (Strategy 2 species) under Fe sufficiency and deficiency. Plants (+Si or-Si) were grown initially with Fe, and then Fe was removed from the nutrient solution. The plants were then analysed using a combined approach including LA-ICP-MS images for each element of interest, the analysis of the Fe and Si concentration at different cell layers of root and leaf cross sections by SEM-EDX, and determining the apoplastic Fe, total micronutrient concentration and oxidative stress indexes. A different Si effect was observed depending on plant Fe status. Under Fe sufficiency, Si supply increased Fe root plaque formation, decreasing Fe concentration inside the root and increasing the oxidative stress in the plants. Therefore, Fe acquisition strategies were activated, and Fe translocation rate to the aerial parts was increased, even under an optimal Fe supply. Under Fe deficiency, +Si plants absorbed Fe from the plaque more rapidly than -Si plants, due to the previous activation of Fe deficiency strategies during the growing period (+Fe + Si). Higher Fe plaque formation due to Si supply during the growing period reduced Fe uptake and could activate Fe deficiency strategies in rice, making it more efficient against Fe chlorosis alterations. Silicon influenced Mn and Cu distribution in root. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

High resolution mass spectrometric brain proteomics by MALDI-FTICR-MS combined with determination of P, S, Cu, Zn and Fe by LA-ICP-MS

NASA Astrophysics Data System (ADS)

Becker, J. Susanne; Zoriy, Miroslav; Przybylski, Michael; Becker, J. Sabine

2007-03-01

The combination of atomic and molecular mass spectrometric methods was applied for characterization and identification of several human proteins from Alzheimer's diseased brain. A brain protein mixture was separated by two-dimensional (2D) gel electrophoresis and the protein spots were fast screened by microlocal analysis using LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) in respect to phosphorus, sulfur, copper, zinc and iron content. Five selected protein spots in 2D gel containing these elements were investigated after tryptic digestion by matrix assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS). Than element concentrations (P, Cu, Zn and Fe) were determined in three identified human brain proteins by LA-ICP-MS in the 2D gel. Results of structure analysis of human brain proteins by MALDI-FTICR-MS were combined with those of the direct determination of phosphorus, copper, zinc and iron concentrations in protein spots with LA-ICP-MS. From the results of atomic and molecular mass spectrometric techniques the human brain proteins were characterized in respect to their structure, sequence, phosphorylation state and metal content as well.

Metal(loid)s behaviour in soils amended with nano zero-valent iron as a function of pH and time.

PubMed

Vítková, Martina; Rákosová, Simona; Michálková, Zuzana; Komárek, Michael

2017-01-15

Nano zero-valent iron (nZVI) is currently investigated as a stabilising amendment for contaminated soils. The effect of pH (4-8) and time (48 and 192 h) on the behaviour of nZVI-treated Pb-Zn and As-contaminated soil samples was assessed. Additionally, soil leachates were subsequently used to study the direct interaction between soil solution components and nZVI particles in terms of mineralogical changes and contaminant retention. A typical U-shaped leaching trend as a function of pH was observed for Cd, Pb and Zn, while As was released predominantly under alkaline conditions. Oxidising conditions prevailed, so pH was the key controlling parameter rather than redox conditions. Generally, longer contact time resulted in increased soluble concentrations of metal(loid)s. However, the stabilisation effect of nZVI was only observed after the direct soil leachate-nZVI interactions, showing enhanced redox and sorption processes for the studied metals. A significant decrease of dissolved As concentrations was observed for both experimental soils, but with different efficiencies depending on neutralisation capacity, organic matter content or solid fractionation of As related to the origin of the soils. Scorodite (FeAsO 4 ·2H 2 O) was predicted as a potential solubility-controlling mineral phase for As. Sorption of metal(loid)s onto secondary Fe- and Al-(oxyhydr)oxides (predicted to precipitate at pH > 5) represents an important scavenger mechanism. Moreover, transmission electron microscopy confirmed the retention of Zn and Pb under near-neutral and alkaline conditions by newly formed Fe oxides or aluminosilicates. This study shows that the efficiency of nZVI application strongly depends not only on soil pH-Eh conditions and contaminant type, but also on the presence of organic matter and other compounds such as Al/Fe/Mn oxyhydroxides and clay minerals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Interference of three herbicides on iron acquisition in maize plants.

PubMed

Bartucca, Maria Luce; Di Michele, Alessandro; Del Buono, Daniele

2018-05-07

The use of herbicides to control weed species could lead to environmental threats due to their persistence and accumulation in the ecosystems and cultivated fields. Nonetheless, the effect of these compounds on plant mineral nutrition in crops has been barely investigated. This study aimed at ascertaining the effect of three herbicides (S-metolachlor, metribuzin and terbuthylazine) on the capacity of maize to acquire iron (Fe). Interferences on plant growth and reductions on the Fe contents were found in the plants treated. Furthermore, root cell viability and functionality losses were ascertained following the treatments, which, in turn, decreased the amount of phytosiderophores (PSs) released by the roots. An investigation carried out in greater depth on root apices of treated plants using an FE-SEM (Scanning Electron Microscope) coupled with EDX (Energy Dispersive X-ray) indicated that the reductions on Fe content started in this part of the roots. Lastly, decreases were found also in copper (Cu +2 ), zinc (Zn +2 ) and manganese (Mn +2 ) content in root apices. Copyright © 2018 Elsevier Ltd. All rights reserved.

A probable risk factor of female breast cancer: study on benign and malignant breast tissue samples.

PubMed

Rehman, Sohaila; Husnain, Syed M

2014-01-01

The study reports enhanced Fe, Cu, and Zn contents in breast tissues, a probable risk factor of breast cancer in females. Forty-one formalin-fixed breast tissues were analyzed using atomic absorption spectrophotometry. Twenty malignant, six adjacent to malignant and 15 benign tissues samples were investigated. The malignant tissues samples were of grade 11 and type invasive ductal carcinoma. The quantitative comparison between the elemental levels measured in the two types of specimen (benign and malignant) tissues (removed after surgery) suggests significant elevation of these metals (Fe, Cu, and Zn) in the malignant tissue. The specimens were collected just after mastectomy of women aged 19 to 59 years from the hospitals of Islamabad and Rawalpindi, Pakistan. Most of the patients belong to urban areas of Pakistan. Findings of study depict that these elements have a promising role in the initiation and development of carcinoma as consistent pattern of elevation for Fe, Cu, and Zn was observed. The results showed the excessive accumulation of Fe (229 ± 121 mg/L) in malignant breast tissue samples of patients (p < 0.05) to that in benign tissues samples (49.1 ± 11.4 mg/L). Findings indicated that excess accumulation of iron in malignant tissues can be a risk factor of breast cancer. In order to validate our method of analysis, certified reference material muscle tissue lyophilized (IAEA) MA-M-2/TM was analyzed for metal studied. Determined concentrations were quite in good agreement with certified levels. Asymmetric concentration distribution for Fe, Cu, and Zn was observed in both malignant and benign tissue samples.

Zn and Fe complexes containing a redox active macrocyclic biquinazoline ligand.

PubMed

Banerjee, Priyabrata; Company, Anna; Weyhermüller, Thomas; Bill, Eckhard; Hess, Corinna R

2009-04-06

A series of iron and zinc complexes has been synthesized, coordinated by the macrocyclic biquinazoline ligand, 2-4:6-8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2'-biquinazolino)-[15]-1,3,5,8,10,14-hexaene-1,3,7,9,11,14-N(6) (Mabiq). The Mabiq ligand consists of a bipyrimidine moiety and two dihydropyrrole units. The electronic structures of the metal-Mabiq complexes have been characterized using spectroscopic and density-functional theory (DFT) computational methods. The parent zinc complex exhibits a ligand-centered reduction to generate the metal-coordinated Mabiq radical dianion, establishing the redox non-innocence of this ligand. Iron-Mabiq complexes have been isolated in three oxidation states. This redox series includes low-spin ferric and low-spin ferrous species, as well as an intermediate-spin Fe(II) compound. In the latter complex, the iron ion is antiferromagnetically coupled to a Mabiq-centered pi-radical. The results demonstrate the rich redox chemistry and electronic properties of metal complexes coordinated by the Mabiq ligand.

EAG Eminent Speaker: Cold war biogeochemistry: Microbes as architects for metal attenuation

NASA Astrophysics Data System (ADS)

Küsel, K.

2012-04-01

Legacy uranium mining in the area of Ronneburg, Germany, has resulted in extensive outflow of highly heavy metal contaminated ground and upcoming mine waters. Mine water flows along a grassland into a small creek and forms iron-rich precipitates yielding rust-colored terraces at the creek bank. These iron oxyhydroxides could have been formed by iron oxidizing bacteria (FeOB) or by chemical oxidation. Precipitates may serve as important biogeochemical interfaces, because heavy metals can adsorb or co-precipitate with Fe(II) or Fe(III) minerals. Thus, microbial Fe(II) oxidation but also the reductive dissolution of iron oxides can be important processes affecting the stability of metal contaminants. Here we present a study on the potential for iron cycling processes and on indigenous bacterial communities in this acidic creek. Oxic and anoxic in vitro sediment incubations revealed iron oxidation and reduction rates of same magnitude, indicating active iron cycling regardless of pH. XRD and TEM comparing the suspended particle load of water samples with fresh creek sediment showed that amorphous particles likely formed first, then aged to become more crystalline iron oxyhydroxides, such as akaganeite and goethite. During this aging process some of the initially smooth, 50-300 nm spherical particles may have formed nano-sized needles, which could potentially provide high reactive surface area for chemical and biological reactions. Surprisingly, total and dissolved metal concentrations in creek water and sediment revealed that elements such as Mn, Si, Ni, or Zn stayed mostly in solution. Only some metals such as Cu, Cr, and U seemed to be particle-associated in the water, likely co-precipitated with or adsorbed onto freshly-precipitating minerals. Pelagic and particle-associated organisms from water as well as fresh sediments were used for 16S rRNA gene cloning and sequencing and showed that members of the Proteobacteria (mainly Betaproteobacteria and Deltaproteobacteria) dominated bacterial communities. The relative fraction of FeOB-related clones was especially high in upcoming underground water and sediment of the adjacent creek site. Up to 80% of clones in sediment microbial 16S rRNA gene clone libraries had ≥97% sequence similarity to reported FeOM or FeRM, demonstrating a strong link to function, even on RNA level. Three novel moderately acidophilic FeOM strains, Thiomonas sp. FB-Cd and FB-6 and Bordetella sp. FB-8, were isolated from pH 6.3 sediment. FB-6 is likely involved in in situ iron oxidation as it has high similarity to a RNA-derived clone from this sediment. Our results demonstrated active microbial iron cycling in heavy metal contaminated creeks, which have important implications for understanding natural attenuation.

In Situ Mineralization of Magnetite Nanoparticles in Chitosan Hydrogel

NASA Astrophysics Data System (ADS)

Wang, Yongliang; Li, Baoqiang; Zhou, Yu; Jia, Dechang

2009-09-01

Based on chelation effect between iron ions and amino groups of chitosan, in situ mineralization of magnetite nanoparticles in chitosan hydrogel under ambient conditions was proposed. The chelation effect between iron ions and amino groups in CS-Fe complex, which led to that chitosan hydrogel exerted a crucial control on the magnetite mineralization, was proved by X-ray photoelectron spectrum. The composition, morphology and size of the mineralized magnetite nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and thermal gravity. The mineralized nanoparticles were nonstoichiometric magnetite with a unit formula of Fe2.85O4 and coated by a thin layer of chitosan. The mineralized magnetite nanoparticles with mean diameter of 13 nm dispersed in chitosan hydrogel uniformly. Magnetization measurement indicated that superparamagnetism behavior was exhibited. These magnetite nanoparticles mineralized in chitosan hydrogel have potential applications in the field of biotechnology. Moreover, this method can also be used to synthesize other kinds of inorganic nanoparticles, such as ZnO, Fe2O3 and hydroxyapatite.

Diamond and Unusual Minerals Discovered from the Chromitite in Polar Ural: A First Report

NASA Astrophysics Data System (ADS)

Yang, J.; Bai, W.; Fang, Q.; Meng, F.; Chen, S.; Zhang, Z.

2007-12-01

Ultrahigh pressure (UHP) minerals, such as diamond, coesite, and pseudomorphs of octahedral olivine, and as well as about 80 other mineral species have been recovered from podiform chromitites of the Luobusa ophiolite, southern Tibet, and a new mineral, Luobusaite (Fe0.82Si2), has been approved recently by CNMMN. The UHP minerals from Luobusa are controversial because they have not found in situ and because ophiolites are currently believed to form at shallow levels above oceanic spreading centers. More detailed study and experimental work are needed to understand the origin and significance of these unusual minerals and investigations of other ophiolites are needed to determine if such minerals occur elsewhere. For this purpose, we collected about 1500 kg of chromitite from two orebodies in an ultramafic body in the Polar Urals. Thus far, more than 60 different mineral species have been separated from these ores. The most exciting discovery is the common occurrence of diamond, a typical UHP mineral in the Luobusa chromitites. Diamonds from Ural chromitite are clear, colorless, well-developed crystals with octahedral morphology, generally 0.2-0.3 mm in size. Attached with the diamonds and perhaps also occurring as inclusions within them are many minerals as chromite, MnNiCrFe alloy, native Si and Ta, corundum, zircon, feldspar, garnet, moissanite, confirming their natural origin and suggesting a long residence time in the mantle. Other mineral group include: (1) native elements: Cr, W, Ni, Co, Si, Al and Ta; (2) carbides: SiC and WC; (3) alloys: Cr-Fe, Si-Al-Fe, Ni-Cu, Ag-Au, Ag-Sn, Fe-Si, Fe-P, and Ag-Zn-Sn; (4) oxides: NiCrFe, PbSn, REE, rutile and Si- bearing rutile, ilmenite, corundum, chromite, MgO, and SnO2; (5) silicates: kyanite, pseudomorphs of octahedral olivine, zircon, garnet, feldspar, and quartz,; (6) sulfides of Fe, Ni, Cu, Mo, Pb, Ab, AsFe, FeNi, CuZn, and CoFeNi; and (7) iron groups: native Fe, FeO, and Fe2O3. These minerals are very similar in composition and structure to those reported from the Luobusa chromitites. For examples, some spherules of native iron contain spherical inclusions of FeO, exactly like comparable grains in the Luobusa sample.

Marine molluscs as biomonitors for heavy metal levels in the Gulf of Suez, Red Sea

NASA Astrophysics Data System (ADS)

Hamed, Mohamed A.; Emara, Ahmed M.

2006-05-01

Levels of the heavy metals Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Iron (Fe) and Manganese (Mn) were determined in coastal water, sediments and soft tissues of the gastropod limpet, Patella caerulea, and the bivalve, Barbatus barbatus, from seven different stations in the western coast of the Gulf of Suez. The concentrations of heavy metals in water ranged between 3.37-4.78, 18.83-21.46, 2.75-3.17, 0.22-0.27, 0.99-1.21, 2.69-3.65, 3.75-4.56 μg L - 1 and 23.82-32.78 mg g - 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The corresponding concentration values in the sediments were 8.65-12.16, 51.78-58.06, 36.52-42.15, 3.23-3.98, 9.03-12.75, 34.31-49.63, 3.28-4.56 and 64.20-70.22 μg g - 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The highest accumulated metals were Fe, Zn and Mn in both P. caerulea and B. barbatus, while the lowest one was Cd. The accumulation of metals was more pronounced in P. caerulea than B. barbatus. The highest concentrations of all metals in water, sediments and mollusca were recorded at Adabiya harbour north of the Gulf, while the lowest concentrations were recorded at Gabal El-Zeit and Hurghada. Land based activities and ships awaiting berth are the main source of metal pollution in the northern part of the Gulf.

Fractionation profile and mobility pattern of metals in sediments from the Mediterranean Coast, Libya.

PubMed

Nasr, Samir M; Okbah, Mohamed A; El Haddad, Huda S; Soliman, Naglaa F

2015-07-01

A five-step sequential extraction technique, following Tessier's protocol, has been applied to determine the chemical association of Cd, Cu, Fe, Pb, and Zn with major sedimentary phases (exchangeable, carbonate, manganese and iron oxides, organic and residual fraction) in surface sediments from 14 stations off the Libyan Mediterranean coast. This study is a first approach of chemical fractionation of these metals in one of the most economically important area of the Libyan coastline in Mediterranean Sea. The total metal content was also determined. The total concentration of metals ranged from 5-10.5 mg/kg for Cd, 9.1-22.7 mg/kg for Cu, 141.8-1056.8 mg/kg for Fe, 18.9-56.9 mg/kg for Pb, and 11.6-30.5 mg/kg for Zn. The results of the partitioning study showed that the residual form was the dominant fraction of the selected metals among most of the studied locations. The degree of surface sediment contamination was computed for risk assessment code (RAC), individual contamination factor (ICF), and Global contamination factor (GCF). Risk assessment code classification showed that the relative amounts of easily dissolved phase of trace metals in the sediments are in the order of Pb>Zn>Cd>Cu>Fe. The results of ICF and GCF showed that Sirt and Abu Kammashand had higher GCF than other sites indicating higher environmental risk. In terms of ICF value, a decrease order in environmental risk by trace metals was Pb>Zn>Cu>Cd>Fe. Therefore, Pb had highest risk to water body.

Nonstoichiometric Zn Ferrite and ZnFe2O4/Fe2O3 Composite Spheres: Preparation, Magnetic Properties, and Chromium Removal

NASA Astrophysics Data System (ADS)

Hang, Chun-Liang; Yang, Li-Xia; Sun, Chang-Mei; Liang, Ying

2018-03-01

Monodisperse and porous nonstoichiometric Zn ferrite can be prepared by a solvothermal method. Such non-Zn ferrite was used to be the precursor for synthesis of ZnFe2O4/Fe2O3 composite via calcination at 600°C for 3 h in air. X-ray powder diffractometer (XRD) and Energy Dispersive Spectrometer (EDS) proved the nonstoichiometry of Zn ferrite synthesized by solvothermal method and the formation of ZnFe2O4/Fe2O3 composite via calcination. TEM image showed that non-Zn ferrite spheres with wormlike nanopore structure were made of primary nanocrystals. BET surface area of non-Zn ferrite was much higher than that of ZnFe2O4/Fe2O3 composite. Saturation magnetization of non-Zn ferrites was significantly higher than that of ZnFe2O4/Fe2O3 composites. Calcination of non-Zn ferrite resulted in the formation of large amount of non-magnetic Fe2O3,which caused a low magnetization of composite. Because of higher BET surface area and higher saturation magnetization, non-Zn ferrite presented better Cr6+ adsorption property than ZnFe2O4/Fe2O3 composites.

Urban runoff treatment using nano-sized iron oxide coated sand with and without magnetic field applying

PubMed Central

2013-01-01

Increase of impervious surfaces in urban area followed with increases in runoff volume and peak flow, leads to increase in urban storm water pollution. The polluted runoff has many adverse impacts on human life and environment. For that reason, the aim of this study was to investigate the efficiency of nano iron oxide coated sand with and without magnetic field in treatment of urban runoff. In present work, synthetic urban runoff was treated in continuous separate columns system which was filled with nano iron oxide coated sand with and without magnetic field. Several experimental parameters such as heavy metals, turbidity, pH, nitrate and phosphate were controlled for investigate of system efficiency. The prepared column materials were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDXA) instruments. SEM and EDXA analyses proved that the sand has been coated with nano iron oxide (Fe3O4) successfully. The results of SEM and EDXA instruments well demonstrate the formation of nano iron oxide (Fe3O4) on sand particle. Removal efficiency without magnetic field for turbidity; Pb, Zn, Cd and PO4 were observed to be 90.8%, 73.3%, 75.8%, 85.6% and 67.5%, respectively. When magnetic field was applied, the removal efficiency for turbidity, Pb, Zn, Cd and PO4 was increased to 95.7%, 89.5%, 79.9%, 91.5% and 75.6% respectively. In addition, it was observed that coated sand and magnetic field was not able to remove NO3 ions. Statistical analyses of data indicated that there was a significant difference between removals of pollutants in two tested columns. Results of this study well demonstrate the efficiency of nanosized iron oxide-coated sand in treatment of urban runoff quality; upon 75% of pollutants could be removed. In addition, in the case of magnetic field system efficiency can be improved significantly. PMID:24360061

Compromised zinc status of experimental rats as a consequence of prolonged iron & calcium supplementation

PubMed Central

Jayalakshmi, S.; Platel, Kalpana

2016-01-01

Background & objectives: Iron supplementation is usually given to pregnant and lactating women who may also have marginal deficiency of zinc. The negative impact of supplemental iron and calcium on zinc status is a cause of concern. The present investigation was undertaken to examine the effect of inclusion of iron and calcium in the diet at supplementary levels on zinc status of experimental rats. Methods: Groups of experimental rats were maintained on diets supplemented with iron (Molar ratio - Zn:Fe 1:30) and calcium (Molar ratio - Zn:Ca 1:667) both individually and in combination for six weeks. Zinc status of these rats was assessed by determining zinc concentration in circulation and in organs, and the activities of zinc containing enzymes in serum and liver. Results: The zinc status of experimental rats receiving supplemental levels of iron and calcium was significantly compromised. Zinc concentration in serum, kidney, spleen and liver was reduced significantly by both these minerals. Six weeks of supplementation of iron and calcium individually, significantly reduced the activity of liver and serum superoxide dismutase and alkaline phosphatase. Activity of liver alcohol dehydrogenase was lowered in calcium supplemented group and in calcium + iron supplemented group, while that of carbonic anhydrase was significantly reduced by iron, calcium and their combination. Interpretation & conclusions: Supplemental levels of iron and calcium, both individually and in combination, significantly compromised the zinc status of experimental rats. This negative effect of these two minerals was more prominent when these were supplemented for a period of six weeks. PMID:27121523

Nanofibrillated Cellulose-Assisted Synthesis of Fiber-Like ZnO-ZnFe2O4 Composites with Enhanced Visible-Light-Driven Photocatalytic Activity

NASA Astrophysics Data System (ADS)

Cai, Aijun; Guo, Aiying; Du, Liqiang; Chang, Yongfang; Wang, Xiuping

2018-05-01

In this article, fiber-like ZnO-ZnFe2O4 composites are obtained by using nanofibrillated cellulose as a biotemplate. The as-prepared composites exhibit strong absorbance in the visible-light region. The ZnO-ZnFe2O4 composites exhibit a similar bandgap (1.88 eV) compared with the ZnFe2O4 (1.85 eV). The ZnO-ZnFe2O4 composites can be easily collected by an external magnet, which contributes to improving the utilization efficiency of the photocatalysts. The photocatalytic activity of the ZnO-ZnFe2O4 catalysts was evaluated by photodegrading rhodamine B (RhB) under visible-light irradiation. Compared with ZnO and ZnFe2O4, the ZnO-ZnFe2O4 catalysts show higher photocatalytic activity due to the efficient electron-hole separation.

A New Test of Copper and Zinc Abundances in Late-Type Stars Using Cu II and Zn II lines in the Near-Ultraviolet

NASA Astrophysics Data System (ADS)

Roederer, Ian

2017-08-01

The copper (Cu, Z = 29) and zinc (Zn, Z = 30) abundances found in late-type stars provide critical constraints on models that predict the yields of massive star supernovae, hypernovae, Type Ia supernovae, and AGB stars, which are essential ingredients in Galactic chemical evolution models. Furthermore, Zn is commonly used to compare the abundance of iron-group elements in the gas phase in high-redshift DLA systems with metallicities in Local Group stars. It is thus important that the observational Cu and Zn abundances in stars are correct. My proposed archive study will address this issue by using archive STIS spectra of 14 stars to provide the first systematic observational tests of non-LTE calculations of Cu and Zn line formation in late-type stars. The non-LTE calculations predict that all LTE [Cu/Fe] abundance ratios presently found in the literature are systematically lower than the true ratios found in stars. The non-LTE calculations for Zn predict that the LTE values in the literature may be systematically overestimated in low-metallicity stars. The LTE abundances of Cu and Zn are derived from Cu I and Zn I lines. The key advance enabled by the use of NUV spectra is the detection of several lines of Cu II and Zn II, which cannot be detected in the optical or infrared. Cu II and Zn II are largely immune to non-LTE effects in the atmospheres of late-type stars. The metallicities of the 14 stars with NUV spectra span -2.6 < [Fe/H] < -0.1, which covers the range of most Cu and Zn abundances reported in the literature. The proposed study will allow me to test the non-LTE calculations and calibrate the stellar abundances.

Season and location effects on serum and liver mineral concentrations of Senepol cattle on St Croix, Virgin Islands.

PubMed

Wildeus, S; McDowell, L R; Fugle, J R

1992-11-01

Serum and liver concentrations of selected macro- and trace minerals were determined in Senepol cattle at 8 sites (4 each in a high and low rainfall region) during the dry and wet season on St Croix. At each site an average of 15 mature, lactating cows, grazing native grass/legume pastures without supplementation were blood sampled each season. Liver samples were collected (n = 51) at slaughter from mature animals originating from the same sites. A preliminary analysis indicated no differences in serum mineral concentrations between mature lactating cows and growing heifers. There were differences between sites for serum magnesium (Mg) (P < 0.001), copper (Cu) (P < 0.05) selenium (Se) (P < 0.001) and zinc (Zn) (P < 0.01) in the dry season, and for Cu (P < 0.01), iron (Fe) (P < 0.001) and Zn (P < 0.01) in the wet season. Higher (P < 0.001) serum concentrations of Mg, Cu, Fe and Zn were observed in the dry season, while Se was higher (P < 0.01) in the wet season. Liver concentrations of Cu and Fe were lower (P < 0.01) and liver molybdenum (Mo) (P < 0.001) and Se (P < 0.05) higher during the dry season. The seasonal differences in serum Cu, Se and Zn concentrations have not been observed in other studies in the Central American region. More than 50% of serum samples were deficient in phosphorus (P) regardless of season, and in Cu and Zn during the wet season. Mineral supplementation should be considered.

Effect of metals on a siderophore producing bacterial isolate and its implications on microbial assisted bioremediation of metal contaminated soils.

PubMed

Gaonkar, Teja; Bhosle, Saroj

2013-11-01

A bacterial isolate producing siderophore under iron limiting conditions, was isolated from mangroves of Goa. Based on morphological, biochemical, chemotaxonomical and 16S rDNA studies, the isolate was identified as Bacillus amyloliquefaciens NAR38.1. Preliminary characterization of the siderophore indicated it to be catecholate type with dihydroxy benzoate as the core component. Optimum siderophore production was observed at pH 7 in mineral salts medium (MSM) without any added iron with glucose as the carbon source. Addition of NaCl in the growth medium showed considerable decrease in siderophore production above 2% NaCl. Fe(+2) and Fe(+3) below 2 μM and 40 μM concentrations respectively, induced siderophore production, above which the production was repressed. Binding studies of the siderophore with Fe(+2) and Fe(+3) indicated its high affinity towards Fe(+3). The siderophore concentration in the extracellular medium was enhanced when MSM was amended with essential metals Zn, Co, Mo and Mn, however, decreased with Cu, while the concentration was reduced with abiotic metals As, Pb, Al and Cd. Significant increase in extracellular siderophore production was observed with Pb and Al at concentrations of 50 μM and above. The effect of metals on siderophore production was completely mitigated in presence of Fe. The results implicate effect of metals on the efficiency of siderophore production by bacteria for potential application in bioremediation of metal contaminated iron deficient soils especially in the microbial assisted phytoremediation processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantification of zinc-porphyrin in dry-cured ham products by spectroscopic methods Comparison of absorption, fluorescence and X-ray fluorescence spectroscopy.

PubMed

Laursen, Kristoffer; Adamsen, Christina E; Laursen, Jens; Olsen, Karsten; Møller, Jens K S

2008-03-01

Zinc-protoporphyrin (Zn-pp), which has been identified as the major pigment in certain dry-cured meat products, was extracted with acetone/water (75%) and isolated from the following meat products: Parma ham, Iberian ham and dry-cured ham with added nitrite. The quantification of Zn-pp by electron absorption, fluorescence and X-ray fluorescence (XRF) spectroscopy was compared (concentration range used [Zn-pp]=0.8-9.7μM). All three hams were found to contain Zn-pp, and the results show no significant difference among the content of Zn-pp quantified by fluorescence, absorbance and X-ray fluorescence spectroscopy for Parma ham and Iberian ham. All three methods can be used for quantification of Zn-pp in acetone/water extracts of different ham types if the content is higher than 1.0ppm. For dry-cured ham with added nitrite, XRF was not applicable due to the low content of Zn-pp (<0.1ppm). In addition, XRF spectroscopy provides further information regarding other trace elements and can therefore be advantageous in this aspect. This study also focused on XRF determination of Fe in the extracts and as no detectable Fe was found in the three types of ham extracts investigated (limit of detection; Fe⩽1.8ppm), it allows the conclusion that iron containing pigments, e.g., heme, do not contribute to the noticeable red colour observed in some of the extracts.

Hydrothermal ore-forming processes in the light of studies in rock- buffered systems: I. Iron-copper-zinc-lead sulfide solubility relations

USGS Publications Warehouse

Hemley, J.J.; Cygan, G.L.; Fein, J.B.; Robinson, G.R.; d'Angelo, W. M.

1992-01-01

Experimental studies, using cold-seal and extraction vessel techniques, were conducted on Fe, Pb, Zn, and Cu sulfide solubilities in chloride soultions at temperatures from 300?? to 700??C and pressures from 0.5 to 2 kbars. The solutions were buffered in pH by quartz monzonite and the pure potassium feldspar-muscovite-quartz assemblage and in fS2-fO2 largely by the assemblage pyrite-pyrrhotite-magnetite. Solubilities increase with increasing temperature and total chloride, and decrease with increasing pressure. The effect of increasing chloride concentration on solubility reflects primarily a shift to lower pH via the silicate buffer reactions. Similarity in behaviour with respect to the temperature and pressure of Fe, Zn, and Pb sulfide solubilities points to similarity in chloride speciation, and the neutral species appear to be dominant in the high-temperature region. -from Authors

Geologic cross sections showing the concentrations of As, Cd, Co, Cu, Cr, Fe, Mo, Ni, Pb, and Zn in acid-insoluble residues of Paleozoic rocks within the Doniphan/Eleven Point Ranger District of the Mark Twain National Forest, Missouri, USA

USGS Publications Warehouse

Lee, Lopaka; Goldhaber, Martin B.

2002-01-01

This report is a product of a U.S. Geological Survey investigation that is focused on characterizing the potential environmental impacts of lead-zinc mining within the Doniphan/Eleven Point ranger district of the Mark Twain national forest. The elemental concentrations of iron (Fe), arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn) in acidinsoluble residues are shown for boreholes along two geologic cross sections within Doniphan/Elevan Point ranger district (Figure 1). The purpose of this report is to characterize, in a general sense, the distribution of economically and environmentally important elements within the rocks and aquifers of the Doniphan/Eleven Point ranger district

Functional Fe3O4@ZnO magnetic nanoparticle-assisted enrichment and enzymatic digestion of phosphoproteins from saliva.

PubMed

Chen, Wei-Yu; Chen, Yu-Chie

2010-11-01

Saliva contains various proteins, particularly abundant are phosphoproteins, that may be related to disease occurrences and that play significant roles in a biological system. Thus, medical diagnostics will benefit tremendously if disease-related protein biomarkers are discovered from saliva. In this paper, we propose and demonstrate an approach using functional zinc oxide coated iron oxide magnetic nanoparticles (Fe(3)O(4)@ZnO MNPs) as affinity probes to selectively enrich phosphoproteins from complex saliva samples and as microwave absorbers to assist the enrichment and subsequent tryptic digestion of trapped proteins under microwave heating. The target species trapped by MNPs were characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) combined with protein database search. Entire analysis time was shortened to less than 20 min. The detection limit of this approach for a monophosphopeptide was as low as 250 pM (10 μL).

The Role of Transition Metal Transporters for Iron, Zinc, Manganese, and Copper in the Pathogenesis of Yersinia pestis

PubMed Central

Perry, Robert D.; Bobrov, Alexander G.; Fetherston, Jacqueline D.

2015-01-01

Yersinia pestis, the causative agent of bubonic, septicemic and pneumonic plague, encodes a multitude of Fe transport systems. Some of these are defective due to frameshift or IS element insertions, while others are functional in vitro but have no established role in causing infections. Indeed only 3 Fe transporters (Ybt, Yfe and Feo) have been shown to be important in at least one form of plague. The yersiniabactin (Ybt) system is essential in the early dermal/lymphatic stages of bubonic plague, irrelevant in the septicemic stage, and critical in pneumonic plague. Two Mn transporters have been characterized (Yfe and MntH). These two systems play a role in bubonic plague but the double yfe mntH mutant is fully virulent in a mouse model of pneumonic plague. The same in vivo phenotype occurs with a mutant lacking two (Yfe and Feo) of four ferrous transporters. A role for the Ybt siderophore in Zn acquisition has been revealed. Ybt-dependent Zn acquisition uses a transport system completely independent of the Fe-Ybt uptake system. Together Ybt components and ZnuABC play a critical role in Zn acquisition in vivo. Single mutants in either system retain high virulence in a mouse model of septicemic plague while the double mutant is completely avirulent. PMID:25891079

Effects of long-term feeding dairy cows on a diet supplemented with clinoptilolite on certain serum trace elements.

PubMed

Katsoulos, P D; Roubies, N; Panousis, N; Karatzias, H

2005-01-01

The objective of the experiment was to investigate the effect of clinoptilolite (a natural zeolite) supplementation in the ration of dairy cows on serum copper (Cu), zinc (Zn), and iron (Fe) concentrations. Fifty-two clinically healthy Holstein cows were randomly assigned to one of three groups according to their age and parity. The first group (group A) comprised 17 cows fed a ration supplemented with 1.25% clinoptilolite, the second group (group B) comprised also 17 cows was given a ration with 2.5% clinoptilolite, and the third group (group C, the control), comprised 18 cows fed the basal ration that did not contain any clinoptilolite. The experiment started when the cows entered the fourth week before the expected parturition and lasted until the end of lactation. All cows were fed the above concentrates during the entire experimental period. Blood samples were collected from each animal at the starting day of the experiment, at the day of calving, and at monthly intervals thereafter. All samples were tested for serum Cu, Zn, and Fe concentrations. The results showed that the 1.25 and 2.5% supplementation of clinoptilolite did not have any adverse effects on serum concentrations of Cu, Zn, and Fe.

Bioassessment of heavy metal toxicity and enhancement of heavy metal removal by sulfate-reducing bacteria in the presence of zero valent iron.

PubMed

Guo, Jing; Kang, Yong; Feng, Ying

2017-12-01

A simple and valid toxicity evaluation of Zn 2+ , Mn 2+ and Cr 6+ on sulfate-reducing bacteria (SRB) and heavy metal removal were investigated using the SRB system and SRB+Fe 0 system. The heavy metal toxicity coefficient (β) and the heavy metal concentration resulting in 50% inhibition of sulfate reduction (I) from a modeling process were proposed to evaluate the heavy metal toxicity and nonlinear regression was applied to search for evaluation indices β and I. The heavy metal toxicity order was Cr 6+  > Mn 2+  > Zn 2+ . Compared with the SRB system, the SRB+Fe 0 system exhibited a better capability for sulfate reduction and heavy metal removal. The heavy metal removal was above 99% in the SRB+Fe 0 system, except for Mn 2+ . The energy-dispersive spectroscopy (EDS) analysis showed that the precipitates were removed primarily as sulfide for Zn 2+ and hydroxide for Mn 2+ and Cr 6+ .The method of evaluating the heavy metal toxicity on SRB was of great significance to understand the fundamentals of the heavy metal toxicity and inhibition effects on the microorganism and regulate the process of microbial sulfate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of transition metal transporters for iron, zinc, manganese, and copper in the pathogenesis of Yersinia pestis.

PubMed

Perry, Robert D; Bobrov, Alexander G; Fetherston, Jacqueline D

2015-06-01

Yersinia pestis, the causative agent of bubonic, septicemic and pneumonic plague, encodes a multitude of Fe transport systems. Some of these are defective due to frameshift or IS element insertions, while others are functional in vitro but have no established role in causing infections. Indeed only 3 Fe transporters (Ybt, Yfe and Feo) have been shown to be important in at least one form of plague. The yersiniabactin (Ybt) system is essential in the early dermal/lymphatic stages of bubonic plague, irrelevant in the septicemic stage, and critical in pneumonic plague. Two Mn transporters have been characterized (Yfe and MntH). These two systems play a role in bubonic plague but the double yfe mntH mutant is fully virulent in a mouse model of pneumonic plague. The same in vivo phenotype occurs with a mutant lacking two (Yfe and Feo) of four ferrous transporters. A role for the Ybt siderophore in Zn acquisition has been revealed. Ybt-dependent Zn acquisition uses a transport system completely independent of the Fe-Ybt uptake system. Together Ybt components and ZnuABC play a critical role in Zn acquisition in vivo. Single mutants in either system retain high virulence in a mouse model of septicemic plague while the double mutant is completely avirulent.

Introducing a 2-His-1-Glu Nonheme Iron Center into Myoglobin Confers Nitric Oxide Reductase Activity

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

Y Lin; N Yeung; Y Gao

2011-12-31

A conserved 2-His-1-Glu metal center, as found in natural nonheme iron-containing enzymes, was engineered into sperm whale myoglobin by replacing Leu29 and Phe43 with Glu and His, respectively (swMb L29E, F43H, H64, called Fe{sub B}Mb(-His)). A high resolution (1.65 {angstrom}) crystal structure of Cu(II)-CN{sup -}-Fe{sub B}Mb(-His) was determined, demonstrating that the unique 2-His-1-Glu metal center was successfully created within swMb. The Fe{sub B}Mb(-His) can bind Cu, Fe, or Zn ions, with both Cu(I)-Fe{sub B}Mb(-His) and Fe(II)-Fe{sub B}Mb(-His) exhibiting nitric oxide reductase (NOR) activities. Cu dependent NOR activity was significantly higher than that of Fe in the same metal binding site.more » EPR studies showed that the reduction of NO to N{sub 2}O catalyzed by these two enzymes resulted in different intermediates; a five-coordinate heme-NO species was observed for Cu(I)-Fe{sub B}Mb(-His) due to the cleavage of the proximal heme Fe-His bond, while Fe(II)-Fe{sub B}Mb(-His) remained six-coordinate. Therefore, both the metal ligand, Glu29, and the metal itself, Cu or Fe, play crucial roles in NOR activity. This study presents a novel protein model of NOR and provides insights into a newly discovered member of the NOR family, gNOR.« less

The zinc stable isotope signature of waste rock drainage in Arctic Canada

NASA Astrophysics Data System (ADS)

Matthies, Romy; Blowes, David

2014-05-01

Leachate emerging from a pilot-scale waste rock pile of the Diavik diamond mine, Northwest Territories, was monitored. The well-characterized waste rock consists of granite, pegmatitic granite and biotite schist with an average total sulfur and carbonate carbon concentration of 0.053 and 0.027 wt. %, respectively. During the field seasons of 2011 and 2012, the Zn stable isotope footprint was characterized alongside standard monitoring parameters. pH ranged between 4.3 and 6.8 and carbonate alkalinity was low or undetectable. Al and Fe concentrations averaged 6.78 mg L-1 and 175 µg L-1, respectively. The pH and metal mobility were governed by sulfide oxidation and sorption and co-precipitation onto iron and aluminium hydroxides. The main processes controlling zinc mobility in the range of 0.4 and 4.7 mg L-1 was the oxidative dissolution of sphalerite (ZnS) in the biotite schist and the attenuation of zinc onto secondary iron and aluminium hydroxides and desorption upon the pH declining below the pHpzc. The isotope ratios between -0.16 and +0.19 ‰ (δ66Zn, avg = +0.05 ‰, n = 43) are consistent with values reported from other sphalerite containing deposits. Zn isotope ratios and concentrations were largely uncorrelated suggesting that the processes affecting Zn mobility had little or no impact on the Zn isotope signature. Data indicate, that the Zn isotope ratios of the waste rock leachate may be used as a fingerprint to track anthropogenic, mine-derived Zn sources under varying environmental conditions.

Computational chemistry of modified [MFe3S4] and [M2Fe2S4] clusters: assessment of trends in electronic structure and properties.

PubMed

Jensen, Kasper P; Ooi, Bee-Lean; Christensen, Hans E M

2008-12-18

The aim of this work is to understand the molecular evolution of iron-sulfur clusters in terms of electronic structure and function. Metal-substituted models of biological [Fe(4)S(4)] clusters in oxidation states [M(x)Fe(4-x)S(4)](3+/2+/1+) have been studied by density functional theory (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pd, with x = 1 or 2). Most of these clusters have not been characterized before. For those that have been characterized experimentally, very good agreement is obtained, implying that also the predicted structures and properties of new clusters are accurate. Mean absolute errors are 0.024 A for bond lengths ([Fe(4)S(4)], [NiFe(3)S(4)], [CoFe(3)S(4)]) and 0.09 V for shifts in reduction potentials relative to the [Fe(4)S(4)] cluster. All structures form cuboidal geometries similar to the all-iron clusters, except the Pd-substituted clusters, which instead form highly distorted trigonal and tetragonal local sites in compromised, pseudocuboidal geometries. In contrast to other electron-transfer sites, cytochromes, blue copper proteins, and smaller iron-sulfur clusters, we find that the [Fe(4)S(4)] clusters are very insensitive to metal substitution, displaying quite small changes in reorganization energies and reduction potentials upon substitution. Thus, the [Fe(4)S(4)] clusters have an evolutionary advantage in being robust to pollution from other metals, still retaining function. We analyze in detail the electronic structure of individual clusters and rationalize spin couplings and redox activity. Often, several configurations are very close in energy, implying possible use as spin-crossover systems, and spin states are predicted accurately in all but one case ([CuFe(3)S(4)]). The results are anticipated to be helpful in defining new molecular systems with catalytic and magnetic properties.

Characterization of iron and manganese minerals and their associated microbiota in different mine sites to reveal the potential interactions of microbiota with mineral formation.

PubMed

Park, Jin Hee; Kim, Bong-Soo; Chon, Chul-Min

2018-01-01

Different environmental conditions such as pH and dissolved elements of mine stream induce precipitation of different minerals and their associated microbial community may vary. Therefore, mine precipitates from various environmental conditions were collected and their associated microbiota were analyzed through metagenomic DNA sequencing. Various Fe and Mn minerals including ferrihydrite, schwertmannite, goethite, birnessite, and Mn-substituted δ-FeOOH (δ-(Fe 1-x , Mn x )OOH) were found in the different environmental conditions. The Fe and Mn minerals were enriched with toxic metal(loid)s including As, Cd, Ni and Zn, indicating they can act as scavengers of toxic metal(loid)s in mine streams. Under acidic conditions, Acidobacteria was dominant phylum and Gallionella (Fe oxidizing bacteria) was the predominant genus in these Fe rich environments. Manganese oxidizing bacteria, Hyphomicrobium, was found in birnessite forming environments. Leptolyngbya within Cyanobacteria was found in Fe and Mn oxidizing environments, and might contribute to Fe and Mn oxidation through the production of molecular oxygen. The potential interaction of microbial community with minerals in mine sites can be traced by analysis of microbial community in different Fe and Mn mineral forming environments. Iron and Mn minerals contribute to the removal of toxic metal(loid)s from mine water. Therefore, the understanding characteristics of mine precipitates and their associated microbes helps to develop strategies for the management of contaminated mine water. Copyright © 2017 Elsevier Ltd. All rights reserved.

A combination of a dairy product fermented by lactobacilli and galactooligosaccharides shows additive effects on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor.

PubMed

Takasugi, Satoshi; Ashida, Kinya; Maruyama, Suyaka; Matsukiyo, Yukari; Kaneko, Tetsuo; Yamaji, Taketo

2013-06-01

This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.

New approach for the quantification of metallic species in healthcare products based on optical switching of a Schiff base possessing ONO donor set.

PubMed

Singh, Jaswant; Parkash, Jyoti; Kaur, Varinder; Singh, Raghubir

2017-10-05

A new method is reported for the quantification of some metallic components of healthcare products utilizing a Schiff base chelator derived from 2-hydroxyacetophenone and ethanolamine. The Schiff base chelator recognizes some metallic species such as iron, copper and zinc (important components of some healthcare products), and cadmium (common contaminant in healthcare products) giving colorimetric/fluorimetric response. It coordinates with Fe 2+ /Fe 3+ and Cu 2+ ions via ONO donor set and switches the colour to bright red, green and orange, respectively. Similarly, it switches 'ON' a fluorometric response when coordinates with Zn 2+ and Cd 2+ ions. In the present approach, detailed studies on the colorimetric and fluorimetric response of ONO Schiff base is investigated in detail. The Job plot for the complexation of ONO switch with various metal ions suggested formation of 1:1 (metal-chelator) complex with Fe 2+ , Fe 3+ , and Cu 2+ while 1:2 (metal-chelator) for Zn 2+ and Cd 2+ ions. The limit of detection, limit of quantification are 6.73, 18.0, 25.0, 0.65, 1.10μM and 27.0, 72.0, 100.0, 2.60 and 4.40μM for Fe 2+ , Fe 3+ , Cu 2+ , Zn 2+ and Cd 2+ ions, respectively. Under the optimized conditions, chelator was used for the quantification of important metals present in healthcare products via direct dissolution and furnace treatment during sample preparation. The results were found precise and accurate for both sample preparation techniques using the developed method. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioavailability of zinc in two zinc sulfate by-products of the galvanizing industry.

PubMed

Edwards, H M; Boling, S D; Emmert, J L; Baker, D H

1998-10-01

Two Zn depletion/repletion assays were conducted with chicks to determine the relative bioavailability (RBV) of Zn from two new by-products of the galvanizing industry. Using a soy concentrate-dextrose diet, slope-ratio methodology was employed to evaluate two different products: Fe-ZnSO4 x H2O with 20.2% Fe and 13.0% Zn, and Zn-FeSO4 x H2O with 14.2% Fe and 20.2% Zn. Feed-grade ZnSO4 x H2O was used as a standard. Weight gain, tibia Zn concentration, and total tibia Zn responded linearly (P < 0.01) to Zn supplementation from all three sources. Slope-ratio calculations based on weight gain established average Zn RBV values of 98% for Fe-ZnSO4 x H2O and 102% for Zn-FeSO4 x H2O, and these values were not different (P > 0.10) from the ZnSO4 standard (100%). Slope-ratio calculations based on total tibia Zn established average Zn RBV values of 126% for Fe-ZnSO4 x H2O and 127% for Zn-FeSO4 x H2O, and these values were greater (P < 0.01) than those of the ZnSO4 standard (100%). It is apparent that both mixed sulfate products of Fe and Zn are excellent sources of bioavailable Zn.

Towards bio monitoring of toxic (lead) and essential elements in whole blood from 1- to 72-month old children: a cross-sectional study.

PubMed

Kang-Sheng, Liu; Xiao-Dong, Mao; Juan, Shi; Chun-Fan, Dai; Pingqing, Gu

2015-06-01

Minerals such as zinc, copper, selenium, calcium, and magnesium are essential for normal human development and functioning of the body. They have been found to play important roles in immuno-physiologic functions. The study is to evaluate the distribution and correlation of nonessential (lead) and essential elements in whole blood from 1- to 72-month old children. The cross-sectional study was performed in 1551 children. Six element concentrations, including copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe) and lead (Pb) in the blood were determined by atomic absorption spectrometry. Distributions and correlations of trace elements in different age groups were analyzed and compared. A Pearson correlation controlled for age and gender was used to assess the relationship of non essential (lead) and essential elements. Levels of copper and magnesium were 18.09 ± 4.42 µmol/L and 1.42 ± 0.12 mmol/L, respectively. 6.04% of all children showed copper levels below the normal threshold, the levels of Magnesium were stable in different age groups. Though the overall mean blood zinc and iron concentrations (61.19 ± 11.30 µmol/L and 8.24 ± 0.59 mmol/L, respectively) gradually increased with age and the overall deficiency levels (24.1% and 36.0%, respectively) decreased with age, zinc and iron deficiencies were still very stable. Controlling for gender and age, significant positive correlations were found when comparing copper to zinc, calcium, magnesium, and iron ((r = 0.333, 0.241, 0.417, 0.314 ,p < 0.01); zinc to magnesium and iron (r = 0.440, 0.497p < 0.01); and magnesium to Calcium and iron (r = 0.349, 0.645, p < 0.01). The overall mean blood lead levels (41.16 ± 16.10) were relatively unstable among different age groups. The prevalence of lead intoxication in all children was 1.3% .Calcium levels decreased gradually with age, with an overall concentration of 1.78 ± 0.13 mmol/L. Significant negative correlations were also noted between Pb and Zn, Fe (r = -0.179, -0.124.p < 0.01) .The importance of calcium deficiency and supplementation is well realized, but the severity of iron and zinc deficiency is not well recorded. The degree of lead intoxication in all the children studied was low; The established reference intervals for Cu, Zn, Ca and Mg provide an important guidance for the reasonable supplementation of essential elements during different age groups.

Isotopic composition of zinc, copper, and iron in lunar samples

NASA Astrophysics Data System (ADS)

Moynier, F.; Albarède, F.; Herzog, G. F.

2006-12-01

We determined by ICP-MS the concentrations and isotopic ratios of Fe, Cu, and Zn in the Ti-rich lunar basalt 74275, in the lunar orange glass 74220, and in up to 10 lunar soils, namely, 14163, 15231, 64501, 66041, 68841, 69941, 70011, 72501, 75081, and 76501. Two analyses of zinc in lunar basalt 74275 give δ 66Zn = 0.17‰ and 0.75‰, values within the range of those measured in terrestrial basalts; copper in lunar basalt 74275 has δ 65Cu ˜ +1.4‰, which is isotopically heavier than values observed in terrestrial basalts. In the orange glass, we measured δ 56Fe = -0.24‰, δ 65Cu = -0.42‰, and δ 66Zn ˜ -3.6‰. These values of δ are more negative than those obtained for 74275 and for typical lunar basalts, but for Cu, comparable to those observed in terrestrial sulfides and meteorites. In lunar soils we found 0.11‰ ⩽ δ 56Fe ⩽ 0.51‰, 2.6‰ ⩽ δ 65Cu ⩽ 4.5‰, and 2.2‰ ⩽ δ 66Zn ⩽ 6.4‰. Insofar as we can generalize from a small sample set, S, Fe, Cu, Zn, and Cd show similar trends in isotopic fractionation on the Moon. Lunar basalts have nearly terrestrial isotopic ratios. Relative to the lunar basalt 74275, the pyroclastic glass 74220 is enriched in the lighter isotopes of Fe, Cu, and Zn, and the soils are enriched in the heavier isotopes of Fe, Cu, and Zn. The patterns in the basalts are likely inherited from the source material; the light-isotope enrichments seen in the orange glass originated during lava fountaining or, less probably, during partial condensation of vapor; and the heavy-isotope enrichments in the lunar soils were likely created by a combination of processes that included micrometeorite vaporization and sputtering. In the orange glass, the light-isotope enrichments (relative to lunar basalts) of Zn are larger than those of Cu. If these enrichments reflect accurately the isotopic composition of the gas, they suggest that Cu is more volatile than Zn in the liquid from which the gas derived. A simple model built on the known flux of micrometeorites to the lunar surface and a published estimate that micrometeorites generate 10 times their own mass of vapor, predicts heavy-isotope enrichments comparable to those observed in soils but only if the regolith gardening rate is set at about one twentieth of the generally accepted value of 1 cm/My. This discrepancy may reflect the difference in the time constants for micrometeorite milling and decimeter-scale gardening, or the importance of sputtering.

New diluted ferromagnetic semiconductor with Curie temperature up to 180 K and isostructural to the '122' iron-based superconductors.

PubMed

Zhao, K; Deng, Z; Wang, X C; Han, W; Zhu, J L; Li, X; Liu, Q Q; Yu, R C; Goko, T; Frandsen, B; Liu, Lian; Ning, Fanlong; Uemura, Y J; Dabkowska, H; Luke, G M; Luetkens, H; Morenzoni, E; Dunsiger, S R; Senyshyn, A; Böni, P; Jin, C Q

2013-01-01

Diluted magnetic semiconductors have received much attention due to their potential applications for spintronics devices. A prototypical system (Ga,Mn)As has been widely studied since the 1990s. The simultaneous spin and charge doping via hetero-valent (Ga(3+),Mn(2+)) substitution, however, resulted in severely limited solubility without availability of bulk specimens. Here we report the synthesis of a new diluted magnetic semiconductor (Ba(1-x)K(x))(Zn(1-y)Mn(y))(2)As(2), which is isostructural to the 122 iron-based superconductors with the tetragonal ThCr(2)Si(2) (122) structure. Holes are doped via (Ba(2+), K(1+)) replacements, while spins via isovalent (Zn(2+),Mn(2+)) substitutions. Bulk samples with x=0.1-0.3 and y=0.05-0.15 exhibit ferromagnetic order with T(C) up to 180 K, which is comparable to the highest T(C) for (Ga,Mn)As and significantly enhanced from T(C) up to 50 K of the '111'-based Li(Zn,Mn)As. Moreover, ferromagnetic (Ba,K)(Zn,Mn)(2)As(2) shares the same 122 crystal structure with semiconducting BaZn(2)As(2), antiferromagnetic BaMn(2)As(2) and superconducting (Ba,K)Fe(2)As(2), which makes them promising for the development of multilayer functional devices.

Magnetically separable core–shell ZnFe{sub 2}O{sub 4}@ZnO nanoparticles for visible light photodegradation of methyl orange

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

Kulkarni, Suresh D., E-mail: suresh.dk@manipal.edu; Kumbar, Sagar; Menon, Samvit G.

Highlights: • Phase pure, magnetic ZnFe{sub 2}O{sub 4}@ZnO nanoparticles synthesized with excellent yield. • ZnFe{sub 2}O{sub 4}@ZnO displayed higher UV photocatalytic efficiency than ZnO nanoparticles. • First report on visible light photodegradation of methyl orange by ZnFe{sub 2}O{sub 4}@ZnO. • Excellent reusability of ZnFe{sub 2}O{sub 4}@ZnO nanoparticles observed for azo dye removal. - Abstract: Visible light photodegradation of aqueous methyl orange using magnetically separable core–shell ZnFe{sub 2}O{sub 4}@ZnO nanoparticles is reported. A combination of low temperature (190 °C) microwave synthesis and hydrothermal method were used to prepare phase pure material with excellent yield (95%). The magnetic separability, surface area ofmore » 41 m{sup 2}/g and visible light absorption make ZnFe{sub 2}O{sub 4}@ZnO nanoparticles a good solar photocatalyst. ZnFe{sub 2}O{sub 4}@ZnO displayed greater UV photocatalytic efficiency than ZnO owing to the generation of large number of electron-hole pairs. Visible light photodegradation of MO using ZnFe{sub 2}O{sub 4}@ZnO nanoparticles is reported for the first time. Higher first order rate constants under both UV and visible light for core-shell nanoparticles suggested their superiority over its individual oxides. The ZnFe{sub 2}O{sub 4}@ZnO showed excellent reusability with high photocatalytic efficiencies suggesting its suitability for solar photocatalytic applications.« less

Dietary exposure to essential and toxic trace elements from a Total diet study in an adult Lebanese urban population.

PubMed

Nasreddine, L; Nashalian, O; Naja, F; Itani, L; Parent-Massin, D; Nabhani-Zeidan, M; Hwalla, N

2010-05-01

This study assesses, by the Total diet study approach, the adequacy of micronutrient intake (Co, Cu, Fe, Mn, Ni, Zn) and the dietary exposure of a Lebanese adult urban population to two toxic elements (Cd, Pb). The foods that made up the average 'total diet' were derived from a previous individual consumption survey. A total of 1215 individual foods were collected, prepared and cooked prior to analysis. Analytical quantification was performed using inductively coupled plasma mass spectrometry. Average daily intakes of Co (11.4 microg/day), Cu (1104.19 microg/day), Fe (13.00 mg/day), Mn (2.04 mg/day), Ni (126.27 microg/day) and Zn (10.97 mg/day) were below toxicological reference values and were found to satisfy nutritional recommendations, except for manganese in men and iron in women. Average dietary exposure to Pb and Cd represented 3.2% and 21.7% of the respective provisional tolerable weekly intakes. Estimates of dietary intakes of iron appeared to be inadequate for 63% of adult women. These findings should constitute a current measure of assessing the adequacy and safety of foods consumed in Lebanon and may be a basis for future monitoring studies. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Synthesis of metal-doped Mn-Zn ferrite from the leaching solutions of vanadium slag using hydrothermal method

NASA Astrophysics Data System (ADS)

Liu, Shiyuan; Wang, Lijun; Chou, Kuochih

2018-03-01

Using vanadium slag as raw material, Metal-doped Mn-Zn ferrites were synthesized by multi-step processes including chlorination of iron and manganese by NH4Cl, selective oxidation of Fe cation, and hydrothermal synthesis. The phase composition and magnetic properties of synthesized metal-doped Mn-Zn ferrite were characterized by X-ray powder diffraction, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photon spectra (XPS) and physical property measurement. It was found that Mn/Zn mole ratio significantly affected the magnetic properties and ZnCl2 content significantly influenced the purity of the phase of ferrite. Synthesized metal-doped Mn-Zn ferrite, exhibiting a larger saturation magnetization (Ms = 60.01 emu/g) and lower coercivity (Hc = 8.9 Oe), was obtained when the hydrothermal temperature was controlled at 200 °C for 12 h with a Mn/Zn mole ratio of 4. The effect of ZnCl2 content, Mn/Zn mole ratio and temperature on magnetic properties of the synthesized metal-doped Mn-Zn ferrite were systemically investigated. This process provided a new insight to utilize resources in the aim of obtaining functional materials.

Cytotoxicity, permeability, and inflammation of metal oxide nanoparticles in human cardiac microvascular endothelial cells: cytotoxicity, permeability, and inflammation of metal oxide nanoparticles.

PubMed

Sun, Jing; Wang, Shaochuang; Zhao, Dong; Hun, Fei Han; Weng, Lei; Liu, Hui

2011-10-01

Wide applications and extreme potential of metal oxide nanoparticles (NPs) increase occupational and public exposure and may yield extraordinary hazards for human health. Exposure to NPs has a risk for dysfunction of the vascular endothelial cells. The objective of this study was to assess the cytotoxicity of six metal oxide NPs to human cardiac microvascular endothelial cells (HCMECs) in vitro. Metal oxide NPs used in this study included zinc oxide (ZnO), iron(III) oxide (Fe(2)O(3)), iron(II,III) oxide (Fe(3)O(4)), magnesium oxide (MgO), aluminum oxide (Al(2)O(3)), and copper(II) oxide (CuO). The cell viability, membrane leakage of lactate dehydrogenase, intracellular reactive oxygen species, permeability of plasma membrane, and expression of inflammatory markers vascular cell adhesion molecule-1, intercellular adhesion molecule-1, macrophage cationic peptide-1, and interleukin-8 in HCMECs were assessed under controlled and exposed conditions (12-24 h and 0.001-100 μg/ml of exposure). The results indicated that Fe(2)O(3), Fe(3)O(4), and Al(2)O(3) NPs did not have significant effects on cytotoxicity, permeability, and inflammation response in HCMECs at any of the concentrations tested. ZnO, CuO, and MgO NPs produced the cytotoxicity at the concentration-dependent and time-dependent manner, and elicited the permeability and inflammation response in HCMECs. These results demonstrated that cytotoxicity, permeability, and inflammation in vascular endothelial cells following exposure to metal oxide nanoparticles depended on particle composition, concentration, and exposure time. © Springer Science+Business Media B.V. 2011

Organic electrolyte-based rechargeable zinc-ion batteries using potassium nickel hexacyanoferrate as a cathode material

NASA Astrophysics Data System (ADS)

Chae, Munseok S.; Heo, Jongwook W.; Kwak, Hunho H.; Lee, Hochun; Hong, Seung-Tae

2017-01-01

This study demonstrates an organic electrolyte-based rechargeable zinc-ion battery (ZIB) using Prussian blue (PB) analogue potassium nickel hexacyanoferrate K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-086) as the cathode material. KNF-086 is prepared via electrochemical extraction of potassium ions from K1.51Ni[Fe(CN)6]0.954(H2O)0.766 (KNF-151). The cell is composed of a KNF-086 cathode, a zinc metal anode, and a 0.5 M Zn(ClO4)2 acetonitrile electrolyte. This cell shows a reversible discharge capacity of 55.6 mAh g-1 at 0.2 C rate with the discharge voltage at 1.19 V (vs. Zn2+/Zn). As evidenced by Fourier electron density analysis with powder XRD data, the zinc-inserted phase is confirmed as Zn0.32K0.86Ni[Fe(CN)6]0.954(H2O)0.766 (ZKNF-086), and the position of the zinc ion in ZKNF-086 is revealed as the center of the large interstitial cavities of the cubic PB. Compared to KNF-086, ZKNF-086 exhibits a decreased unit cell parameter (0.9%) and volume (2.8%) while the interatomic distance of d(Fe-C) increased (from 1.84 to 1.98 Å), and the oxidation state of iron decreases from 3 to 2.23. The organic electrolyte system provides higher zinc cycling efficiency (>99.9%) than the aqueous system (ca. 80%). This result demonstrates an organic electrolyte-based ZIB, and offers a crucial basis for understanding the electrochemical intercalation chemistry of zinc ions in organic electrolytes.

Explaining the variability in recommended intakes of folate, vitamin B12, iron and zinc for adults and elderly people.

PubMed

Doets, Esmée L; Cavelaars, Adrienne E J M; Dhonukshe-Rutten, Rosalie A M; van 't Veer, Pieter; de Groot, Lisette C P G M

2012-05-01

To signal key issues for harmonising approaches for establishing micronutrient recommendations by explaining observed variation in recommended intakes of folate, vitamin B12, Fe and Zn for adults and elderly people. We explored differences in recommended intakes of folate, vitamin B12, Fe and Zn for adults between nine reports on micronutrient recommendations. Approaches used for setting recommendations were compared as well as eminence-based decisions regarding the selection of health indicators indicating adequacy of intakes and the consulted evidence base. In nearly all reports, recommendations were based on the average nutrient requirement. Variation in recommended folate intakes (200-400 μg/d) was related to differences in the consulted evidence base, whereas variation in vitamin B12 recommendations (1.4-3.0 μg/d) was due to the selection of different CV (10-20 %) and health indicators (maintenance of haematological status or basal losses). Variation in recommended Fe intakes (men 8-10 mg/d, premenopausal women 14.8-19.6 mg/d, postmenopausal women 7.5-10.0 mg/d) was explained by different assumed reference weights and bioavailability factors (10-18 %). Variation in Zn recommendations (men 7-14 mg/d, women 4.9-9.0 mg/d) was also explained by different bioavailability factors (24-48 %) as well as differences in the consulted evidence base. For the harmonisation of approaches for setting recommended intakes of folate, vitamin B12, Fe and Zn across European countries, standardised methods are needed to (i) select health indicators and define adequate biomarker concentrations, (ii) make assumptions about inter-individual variation in requirements, (iii) derive bioavailability factors and (iv) collate, select, interpret and integrate evidence on requirements.

Changes of Bone-Related Minerals during Denosumab Administration in Post-Menopausal Osteoporotic Patients.

PubMed

Suzuki, Takako; Nakamura, Yukio; Kato, Hiroyuki

2017-08-13

This retrospective study included 21 patients with primary osteoporosis who were treated with the anti-resorption drug, denosumab. To date, there has been no detailed report on the changes of bone-related minerals after anti-resorption drug therapy. Twenty-one post-menopausal females were retrospectively enrolled. Serum zinc (Zn), magnesium (Mg), iron (Fe), copper (Cu), grip strength, and estimated glomerular filtration rate (eGFR) were examined at one week and 1, 2, 4, 6, 8, 10, and 12 months. Lumbar spine (L1-4) bone mineral density (L-BMD) and bilateral total hip BMD (H-BMD) were examined before and at 4, 8, and 12 months after treatment commencement. Serum Zn tended to decrease at one week and one month, and tended to increase during 10 to 12 months. Serum Cu maintained during zero to eight months, then decreased at 10 and 12 months. Serum Fe gradually increased after four months. Serum Mg sharply increased at one week, then decreased further. Grip strength increased for two months, then slightly decreased and maintained 4 to 12 months. eGFR almost maintained for zero to eight months, then slightly decreased thereafter. L-BMD values significantly increased at eight (5.8%) ( p < 0.01) and 12 months (9.8%) ( p < 0.01). H-BMD increased during the period (at 12 months: 3.7%). These results suggest that at later phases of denosumab therapy, Zn and Fe tended to increase while Mg tended to decrease, all of which are important for bone metabolism. Thus, denosumab might improve Zn and Fe metabolism, and thereby likely increase BMD. Since denosumab may not improve Mg, it is better to obtain Mg supplementation during the therapy.

CO2 and vitamin B12 interactions determine bioactive trace metal requirements of a subarctic Pacific diatom.

PubMed

King, Andrew L; Sañudo-Wilhelmy, Sergio A; Leblanc, Karine; Hutchins, David A; Fu, Feixue

2011-08-01

Phytoplankton growth can be limited by numerous inorganic nutrients and organic growth factors. Using the subarctic diatom Attheya sp. in culture studies, we examined how the availability of vitamin B(12) and carbon dioxide partial pressure (pCO(2)) influences growth rate, primary productivity, cellular iron (Fe), cobalt (Co), zinc (Zn) and cadmium (Cd) quotas, and the net use efficiencies (NUEs) of these bioactive trace metals (mol C fixed per mol cellular trace metal per day). Under B(12)-replete conditions, cells grown at high pCO(2) had lower Fe, Zn and Cd quotas, and used those trace metals more efficiently in comparison with cells grown at low pCO(2). At high pCO(2), B(12)-limited cells had ~50% lower specific growth and carbon fixation rates, and used Fe ~15-fold less efficiently, and Zn and Cd ~3-fold less efficiently, in comparison with B(12)-replete cells. The observed higher Fe, Zn and Cd NUE under high pCO(2)/B(12)-replete conditions are consistent with predicted downregulation of carbon-concentrating mechanisms. Co quotas of B(12)-replete cells were ∼5- to 14-fold higher in comparison with B(12)-limited cells, suggesting that >80% of cellular Co of B(12)-limited cells was likely from B(12). Our results demonstrate that CO(2) and vitamin B(12) interactively influence growth, carbon fixation, trace metal requirements and trace metal NUE of this diatom. This suggests the need to consider complex feedback interactions between multiple environmental factors for this biogeochemically critical group of phytoplankton in the last glacial maximum as well as the current and future changing ocean.

Preparation and photo-catalytic activities of FeOOH/ZnO/MMT composite

NASA Astrophysics Data System (ADS)

Zhou, Yao; Liu, Fusheng; Yu, Shitao

2015-11-01

Montmorillonite (MMT) was used as the carrier for synthesis of FeOOH and FeOOH/ZnO nano-material. FeOOH and FeOOH/ZnO were synthesized by the aqueous solutions of Fe(NO3)3-HNO3 and Zn(NO3)2-NaOH/Fe(NO3)3-HNO3 with the carrier of montmorillonite respectively. Transmission electron-microscopy (TEM) and X-ray diffraction (XRD) were used to study the morphology form and structure of the nano-materials. TEM was also used to demonstrate that FeOOH/ZnO can be formed with the appropriate interface. According to UV-vis absorption spectra, FeOOH/ZnO has a better response to visible light than FeOOH and ZnO, which indicates there is some coupling effect between FeOOH and ZnO. Pentachlorophenol (PCP) was used as a representative organic pollutant to evaluate the photo-catalytic efficiency of the FeOOH/ZnO and FeOOH catalysts in visible light (λ > 400 nm). The photo-catalytic efficiency of FeOOH/ZnO/MMT is better than FeOOH/MMT. According to FTIR, changes of pH and TOC, the degradation mechanism was also discussed. PCP was degraded to aromatic ketone and chloro-hydrocarbon compounds and then to H2O, CO2 and HCl.

Characterization and spectroscopic studies of multi-component calcium zinc bismuth phosphate glass ceramics doped with iron ions

NASA Astrophysics Data System (ADS)

Kumar, A. Suneel; Narendrudu, T.; Suresh, S.; Ram, G. Chinna; Rao, M. V. Sambasiva; Tirupataiah, Ch.; Rao, D. Krishna

2018-04-01

Glass ceramics with the composition 10CaF2-20ZnO-(15-x)Bi2O3-55P2O5:x Fe2O3(0≤x≤2.5) were synthesized by melt-quenching technique and heat treatment. These glass ceramics were characterized by XRD and SEM. Spectroscopic studies such as optical absorption, EPR were also carried out on these glass ceramics. From the absorption spectra the observed bands around 438 and 660nm are the octahedral transitions of Fe3+ (d5) ions and another band at about 536 nm is the tetrahedral transition of Fe3+ (d5) ions. The absorption spectrum also consist of a band around 991 nm and is attributed to the octahedral transition of Fe2+ ions. The EPR spectra of the prepared glass ceramics have exhibited two resonance signals one at g1=4.32 and another signal at g2=2.008. The observed decrease in band gap energy up to 2 mol% Fe2O3 doped glass ceramics is an evidence for the change of environment around iron ions and ligands from more covalent to less covalent (ionic) and induces higher concentration of NBOs which causes the depolymerization of the glass ceramic network.

Facing the challenges of Cu, Fe and Zn homeostasis in plants.

PubMed

Palmer, Christine M; Guerinot, Mary Lou

2009-05-01

Plants have recently moved into the spotlight owing to the growing realization that the world needs solutions to energy and food production that are sustainable and environmentally sound. Iron, copper and zinc are essential for plant growth and development, yet the same properties that make these transition metals indispensable can also make them deadly in excess. Iron and copper are most often used for their redox properties, whereas zinc is primarily used for its ability to act as a Lewis acid. Here we review recent advances in the field of metal homeostasis and integrate the findings on uptake and transport of these three metals.

Silica-Coated Nonstoichiometric Nano Zn-Ferrites for Magnetic Resonance Imaging and Hyperthermia Treatment.

PubMed

Starsich, Fabian H L; Sotiriou, Georgios A; Wurnig, Moritz C; Eberhardt, Christian; Hirt, Ann M; Boss, Andreas; Pratsinis, Sotiris E

2016-10-01

Large-scale and reproducible synthesis of nanomaterials is highly sought out for successful translation into clinics. Flame aerosol technology with its proven capacity to manufacture high purity materials (e.g., light guides) up to kg h -1 is explored here for the preparation of highly magnetic, nonstoichiometric Zn-ferrite (Zn 0.4 Fe 2.6 O 4 ) nanoparticles coated in situ with a nanothin SiO 2 layer. The focus is on their suitability as magnetic multifunctional theranostic agents analyzing their T2 contrast enhancing capability for magnetic resonance imaging (MRI) and their magnetic hyperthermia performance. The primary particle size is closely controlled from 5 to 35 nm evaluating its impact on magnetic properties, MRI relaxivity, and magnetic heating performance. Most importantly, the addition of Zn in the flame precursor solution facilitates the growth of spinel Zn-ferrite crystals that exhibit superior magnetic properties over iron oxides typically made in flames. These properties result in strong MRI T2 contrast agents as shown on a 4.7 T small animal MRI scanner and lead to a more efficient heating with alternating magnetic fields. Also, by injecting Zn 0.4 Fe 2.6 O 4 nanoparticle suspensions into pork tissue, MR-images are acquired at clinically relevant concentrations. Furthermore, the nanothin SiO 2 shell facilitates functionalization with polymers, which improves the biocompatibility of the theranostic system. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of iron(III)chelates on the solubility of heavy metals in calcareous soils.

PubMed

Ylivainio, Kari

2010-10-01

In this study I evaluated the effects of complexing agents on the solubility of heavy metals in an incubation experiment up to 56 days when complexing agents were applied as Fe-chelates (Fe-EDDS(S,S), Fe-EDDS(mix), Fe-EDTA and Fe-EDDHA) on calcareous soils at a level sufficient to correct Fe chlorosis (0.1 mmol kg(-1)). Of these ligands, EDDHA was the most efficient in keeping Fe in water-soluble form, and EDDS increased the solubility of Cu and Zn most, and only EDTA increased the solubility of Cd and Pb. EDTA increased the solubility of Ni steadily during the incubation period, equalling about 5-8% of the added EDTA concentration. [S,S]-EDDS was biodegraded within 56 days, whereas EDDS(mix) was less biodegradable. Ni-chelates were the most recalcitrant against biodegradation. The study shows that even a moderate input of chelates to soil increases the solubility of toxic heavy metals and their risk of leaching. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Critical Elements in Fly Ash from the Combustion of Bituminous Coal in Major Polish Power Plants

NASA Astrophysics Data System (ADS)

Bielowicz, Barbara; Botor, Dariusz; Misiak, Jacek; Wagner, Marian

2018-03-01

The concentration of critical elements, including such REE as Fe, Co, W, Zn, Cr, Ni, V, Mn, Ti, Ag, Ga, Ta, Sr, Li, and Cu, in the so-called fly ash obtained from the 9 Polish power plants and 1 thermal power station has been determined. The obtained values, compared with the global average concentration in bituminous coal ash and sedimentary rocks (Clarke values), have shown that the enrichment of fly ash in the specified elements takes place in only a few bituminous coal processing sites in Poland. The enrichment factor (EF) is only slightly higher (the same order of magnitude) than the Clarke values. The enrichment factor in relation to the Clarke value in the Earth's crust reached values above 10 in all of the examined ashes for the following elements: Cr, Ni, V, W, and, in some ash samples, also Cu and Zn. The obtained values are low, only slightly higher than the global average concentrations in sedimentary rocks and bituminous coal ashes. The ferromagnetic grains (microspheres) found in bituminous coal fly ashes seem to be the most economically prospective in recovery of selected critical elements. The microanalysis has shown that iron cenospheres and plerospheres in fly ash contain, in addition to enamel and iron oxides (magnetite and hematite), iron spinels enriched in Co, Cr, Cu, Mn, Ni, W, and Zn.

Exploring the Link between Micronutrients and Phytoplankton in the Southern Ocean during the 2007 Austral Summer

PubMed Central

Hassler, Christel S.; Sinoir, Marie; Clementson, Lesley A.; Butler, Edward C. V.

2012-01-01

Bottle assays and large-scale fertilization experiments have demonstrated that, in the Southern Ocean, iron often controls the biomass and the biodiversity of primary producers. To grow, phytoplankton need numerous other trace metals (micronutrients) required for the activity of key enzymes and other intracellular functions. However, little is known of the potential these other trace elements have to limit the growth of phytoplankton in the Southern Ocean. This study, investigates whether micronutrients other than iron (Zn, Co, Cu, Cd, Ni) need to be considered as parameters for controlling the phytoplankton growth from the Australian Subantarctic to the Polar Frontal Zones during the austral summer 2007. Analysis of nutrient disappearance ratios, suggested differential zones in phytoplankton growth control in the study region with a most intense phytoplankton growth limitation between 49 and 50°S. Comparison of micronutrient disappearance ratios, metal distribution, and biomarker pigments used to identify dominating phytoplankton groups, demonstrated that a complex interaction between Fe, Zn, and Co might exist in the study region. Although iron remains the pivotal micronutrient for phytoplankton growth and community structure, Zn and Co are also important for the nutrition and the growth of most of the dominating phytoplankton groups in the Subantarctic Zone region. Understanding of the parameters controlling phytoplankton is paramount, as it affects the functioning of the Southern Ocean, its marine resources and ultimately the global carbon cycle. PMID:22787456

Heavy metal profile of water, sediment and freshwater cat fish, Chrysichthys nigrodigitatus (Siluriformes: Bagridae), of Cross River, Nigeria.

PubMed

Ayotunde, Ezekiel Olatunji; Offem, Benedict Obeten; Ada, Fidelis Bekeh

2012-09-01

Cross River serves as a major source of drinking water, transportation, agricultural activities and fishing in Cross River State, Nigeria. Since there is no formal control of effluents discharged into the river, it is important to monitor the levels of metals contaminants in it, thus assessing its suitability for domestic and agricultural use. In order to determine this, three sampling stations designated as Ikom (Station I), Obubra Ogada (Station II) and Calabar (Station III) were randomly selected to study. For this, ten samples of the freshwater Silver Catfish (Chryshchythys nigrogitatus) (29.4-39.5cm SL, 310-510g), sediment and water were collected from each sampling Station from June 2009-June 2010. The heavy metals profiles ofZn, Cu, Fe, Co, Pb, Cd and Cr, in water, sediments and fish muscle were analyzed by atomic absorption spectrophotometry (AAS). In fish, the heavy metals concentration was found to be Cu>Fe>Zn>Cu>Pb>Cd>Co; the highest mean concentration of Copper (0.297 +/- 0.022 microg/g), Cadmium (0.011 +/- 0.007 microg/g), Iron (0.371 +/- 0.489 microg/g), Lead (0.008 +/- 0.008 microg/g), were determined for the fish. In water, the order was found to be Fe>Pb>Zn>Cu>Cr>Cd>Co; the highest mean concentration of Iron (0.009 +/- 0.00) microg/g), Copper (0.015 +/- 0.01 microg/g), Lead (0.0002 +/- 0.00 microg/g) Cadmium (0.0006 +/- 0.001 microg/g), Zinc (0.0036 +/- 0.003 microg/g), were observed in the surface water, respectively. The highest mean concentration of Copper (0.037 +/- 0.03 microg/g), Iron (0.053 +/- 0.04 microg/g), Lead (0.0002 +/- 0.00 microg/g), Cobalt (0.0002 +/- 0.00 microg/g), Cadmium (0.0006 +/- 0.001 microg/g) and Zinc (.009 +/- 0.0015 microg/g) was observed in the bottom water. In sediments, the concentration order found was Zn>Fe>Cu>Pb>Co>Cd; the highest mean concentration of 0.057 +/- 0.04 microg/g, 0.043 +/- 0.03 microg/g, 0.0006 +/- 0.00 microg/g, 0.0002 +/- 0.00 microg/g, 0.0009 +/- 0.00 microg/g, 0.099 +/- 0.00404 microg/g in Iron, Copper, Lead, Cobalt, Cadmium and Zinc were observed in the sediment, respectively; Chromium was not detected in the sediment for the whole sampling area. Most of the heavy metals were below the maximum allowable levels set by the WHO, FEPA and USEPA, except Zinc which mean concentration of 0.099 +/- 0.00404 microg/g was above the recommended limit of 0.0766 microg/g of USEPA in the sediment at Ikom. This implies that the waste assimilation capacity of the river is high, a phenomenon that could be ascribed to dilution, sedimentation and continuous water exchange. This is an indication that an urban and industrial waste discharged into the Cross River has a significant effect on the ecological balance of the river. Thus fish species from the Cross River harvested are safe for human consumption.

Sulfur dioxide leaching of spent zinc-carbon-battery scrap

NASA Astrophysics Data System (ADS)

Avraamides, J.; Senanayake, G.; Clegg, R.

Zinc-carbon batteries, which contain around 20% zinc, 35% manganese oxides and 10% steel, are currently disposed after use as land fill or reprocessed to recover metals or oxides. Crushed material is subjected to magnetic separation followed by hydrometallurgical treatment of the non-magnetic material to recover zinc metal and manganese oxides. The leaching with 2 M sulfuric acid in the presence of hydrogen peroxide recovers 93% Zn and 82% Mn at 25 °C. Alkaline leaching with 6 M NaOH recovers 80% zinc. The present study shows that over 90% zinc and manganese can be leached in 20-30 min at 30 °C using 0.1-1.0 M sulfuric acid in the presence of sulfur dioxide. The iron extraction is sensitive to both acid concentration and sulfur dioxide flow rate. The effect of reagent concentration and particle size on the extraction of zinc, manganese and iron are reported. It is shown that the iron and manganese leaching follow a shrinking core kinetic model due to the formation of insoluble metal salts/oxides on the solid surface. This is supported by (i) the decrease in iron and manganese extraction from synthetic Fe(III)-Mn(IV)-Zn(II) oxide mixtures with increase in acid concentration from 1 M to 2 M, and (ii) the low iron dissolution and re-precipitation of dissolved manganese and zinc during prolonged leaching of battery scrap with low sulfur dioxide.

Fate and Distribution of Heavy Metals in Wastewater Irrigated Calcareous Soils

PubMed Central

Stietiya, Mohammed Hashem; Duqqah, Mohammad; Udeigwe, Theophilus; Zubi, Ruba; Ammari, Tarek

2014-01-01

Accumulation of heavy metals in Jordanian soils irrigated with treated wastewater threatens agricultural sustainability. This study was carried out to investigate the environmental fate of Zn, Ni, and Cd in calcareous soils irrigated with treated wastewater and to elucidate the impact of hydrous ferric oxide (HFO) amendment on metal redistribution among soil fractions. Results showed that sorption capacity for Zarqa River (ZR1) soil was higher than Wadi Dhuleil (WD1) soil for all metals. The order of sorption affinity for WD1 was in the decreasing order of Ni > Zn > Cd, consistent with electrostatic attraction and indication of weak association with soil constituents. Following metal addition, Zn and Ni were distributed among the carbonate and Fe/Mn oxide fractions, while Cd was distributed among the exchangeable and carbonate fractions in both soils. Amending soils with 3% HFO did not increase the concentration of metals associated with the Fe/Mn oxide fraction or impact metal redistribution. The study suggests that carbonates control the mobility and bioavailability of Zn, Ni, and Cd in these calcareous soils, even in presence of a strong adsorbent such as HFO. Thus, it can be inferred that in situ heavy metal remediation of these highly calcareous soils using iron oxide compounds could be ineffective. PMID:24723833

Structure and magnetic properties of Fe-doped ZnO prepared by the sol-gel method.

PubMed

Liu, Huilian; Yang, Jinghai; Zhang, Yongjun; Yang, Lili; Wei, Maobin; Ding, Xue

2009-04-08

Zn(0.97)Fe(0.03)O nanoparticles were synthesized by the sol-gel method. X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis revealed that the samples had pure ZnO wurtzite structure and Fe ions were well incorporated into the ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS) showed that both Fe(2+) and Fe(3+) existed in Zn(0.97)Fe(0.03)O. The result of x-ray absorption near-edge structure (XANES) further testified that Fe ions took the place of Zn sites in our samples. Magnetic measurements indicated that Zn(0.97)Fe(0.03)O was ferromagnetic at room temperature.

Chemical characterization of ambient aerosol collected during the northeast monsoon season over the Arabian Sea: Labile-Fe(II) and other trace metals

NASA Astrophysics Data System (ADS)

Johansen, Anne M.; Hoffmann, Michael R.

2003-07-01

Ambient aerosol samples were collected over the Arabian Sea during the month of March of 1997, aboard the German R/V Sonne, as part of the German Joint Global Ocean Flux Study (JGOFS) project. This is the third study in a series of analogous measurements taken over the Arabian Sea during different seasons of the monsoon. Dichotomous high-volume collector samples were analyzed for ferrous iron immediately after collection, while trace metals, anions, and cations were determined upon return to the laboratory. The main crustal component was geochemically well represented by the average crustal composition and amounted to 5.94 ± 3.08 μg m-3. An additional crustal constituent of clay-like character, rich in water-soluble Ca and Mg, was seen in the fine fraction in air masses of Arabian origin. Total ferrous iron concentrations varied from 3.9 to 17.2 ng m-3 and averaged 9.8 ± 3.4 ng m-3, with 87.2% of Fe(II) present in the fine aerosol fraction. Fe(II) concentrations accounted for on average 1.3 ± 0.5% of the total Fe. While ferrous iron in the coarse fraction appeared to be correlated with the main crustal component, the fine Fe(II) fraction exhibited a more complex behavior. The anthropogenic contribution to the aerosol, as traced by Pb, Zn, and some anions and cations, was found to be considerably larger, especially during the first 10 days of this cruise, than in previously collected samples from the inter-monsoon and southwest monsoon of 1995.

Heavy metals translocation and accumulation from the rhizosphere soils to the edible parts of the medicinal plant Fengdan (Paeonia ostii) grown on a metal mining area, China.

PubMed

Shen, Zhang Jun; Xu, De Cong; Chen, Yan Song; Zhang, Zhen

2017-09-01

Fengdan (Paeonia ostii) is one of Chinese 34 famous medicinal materials. This study investigated the concentrations of Arsenic (As), Chromium (Cr), Cadmium (Cd), Copper (Cu), Lead (Pb), Iron (Fe), Manganese (Mn), and Zinc (Zn) in rhizosphere soils, cortex mouton and seeds of Fengdan planted in a metal mining area, China. The mean concentrations of As, Cd, Cu, and Zn in the rhizosphere soils were above the limits set by the Chinese Soil Environmental Quality Standard (GB 15618-1995). The contamination factor (CF) of Cd was >5, while it was >2for As, Cu, Pb, and Zn in all the soils. The integrated pollution index for all the soils was >3 and ˂ 5. Metal concentrations in the edible parts of Fengdan were in the following decreasing order: Mn>Fe>Zn>Cu>Pb>As>Cr≥Cd. The transfer factor mean values for As, Cu, Cd and Fe in the cortex moutan of old Fengdan (over 6 years) were significantly higher than in young Fengdan. Available metal concentrations, pH and soil organic matter content influenced the metal concentrations of the cortex moutan. The results indicated that mining and smelting operations have led to heavy metals contamination of soils and medicinal parts of Fengdan. The major metal pollutants were elemental Cd, Cu, Pb, and Zn. Heavy metals mainly accumulated in the cortex moutan of Fengdan. The mean concentrations of Cd, Cu, and Pb in the old cortex moutan (over 6 years) were above those of the Chinese Green Trade Standards for Medicinal Plants and Preparations in Foreign Trade (WM/T2-2004). Copyright © 2017. Published by Elsevier Inc.

Moving Fe2+ from ferritin ion channels to catalytic OH centers depends on conserved protein cage carboxylates.

PubMed

Behera, Rabindra K; Theil, Elizabeth C

2014-06-03

Ferritin biominerals are protein-caged metabolic iron concentrates used for iron-protein cofactors and oxidant protection (Fe(2+) and O2 sequestration). Fe(2+) passage through ion channels in the protein cages, like membrane ion channels, required for ferritin biomineral synthesis, is followed by Fe(2+) substrate movement to ferritin enzyme (Fox) sites. Fe(2+) and O2 substrates are coupled via a diferric peroxo (DFP) intermediate, λmax 650 nm, which decays to [Fe(3+)-O-Fe(3+)] precursors of caged ferritin biominerals. Structural studies show multiple conformations for conserved, carboxylate residues E136 and E57, which are between ferritin ion channel exits and enzymatic sites, suggesting functional connections. Here we show that E136 and E57 are required for ferritin enzyme activity and thus are functional links between ferritin ion channels and enzymatic sites. DFP formation (Kcat and kcat/Km), DFP decay, and protein-caged hydrated ferric oxide accumulation decreased in ferritin E57A and E136A; saturation required higher Fe(2+) concentrations. Divalent cations (both ion channel and intracage binding) selectively inhibit ferritin enzyme activity (block Fe(2+) access), Mn(2+) < Co(2+) < Cu(2+) < Zn(2+), reflecting metal ion-protein binding stabilities. Fe(2+)-Cys126 binding in ferritin ion channels, observed as Cu(2+)-S-Cys126 charge-transfer bands in ferritin E130D UV-vis spectra and resistance to Cu(2+) inhibition in ferritin C126S, was unpredicted. Identifying E57 and E136 links in Fe(2+) movement from ferritin ion channels to ferritin enzyme sites completes a bucket brigade that moves external Fe(2+) into ferritin enzymatic sites. The results clarify Fe(2+) transport within ferritin and model molecular links between membrane ion channels and cytoplasmic destinations.

Heavy metals in handloom-dyeing effluents and their biosorption by agricultural byproducts.

PubMed

Nahar, Kamrun; Chowdhury, Md Abul Khair; Chowdhury, Md Akhter Hossain; Rahman, Afzal; Mohiuddin, K M

2018-03-01

The Madhabdi municipality in the Narsingdi district of Bangladesh is a well-known area for textile, handloom weaving, and dyeing industries. These textile industries produce a considerable amount of effluents, sewage sludge, and solid waste materials every day that they directly discharge into surrounding water bodies and agricultural fields. This disposal poses a serious threat to the overall epidemic and socio-economic pattern of the locality. This research entailed the collection of 34 handloom-dyeing effluent samples from different handloom-dyeing industries of Madhabdi, which were then analyzed to determine the contents of the heavy metals iron (Fe), zinc (Zn), copper (Cu), chromium (Cr), manganese (Mn), lead (Pb), and cadmium (Cd). Average concentrations of Fe, Cr, Cu, Pb, Mn, and Zn were 3.81, 1.35, 1.70, 0.17, 0.75, and 0.73 mg L -1 , respectively, whereas Cd content was below the detectable limit of the atomic adsorption spectrophotometer. The concentrations of Fe, Cr, Cu, Pb, and Mn exceed the industrial effluent discharge standards (IEDS) for inland surface water and irrigation water guideline values. A biosorption experiment of the heavy metals (Fe, Cr, Cu, Mn, and Zn) was conducted without controlling for any experimental parameters (e.g., pH, temperature, or other compounds present in the effluent samples) by using four agricultural wastes or byproducts, namely rice husk, sawdust, lemon peel, and eggshell. Twenty grams of each biosorbent was added to 1 L of effluent samples and stored for 7 days. The biosorption capacity of each biosorbent is ranked as follows: eggshell, sawdust, rice husk, and lemon peel. Furthermore, the biosorption affinity of each metal ion was found in the following order: Cu and Cr (both had similar biosorption affinity), Zn, Fe, Mn. The effluents should not be discharged before treatment, and efficient treatment of effluents is possible with eggshell powder or sawdust at a rate of 20 g of biosorbent per liter of effluents.

Recognition of iron ions by carbazole-desferrioxamine fluorescent sensor and its application in total iron detection in airbone particulate matter.

PubMed

Delattre, François; Cazier-Dennin, Francine; Leleu, Ludovic; Dewaele, Dorothée; Landy, David; Mallard, Isabelle; Danjou, Pierre-Edouard

2015-11-01

This work reports on an efficient microwave irradiation synthesis of a new fluorescent chemosensor based on desferrioxamine B (DFO-B) and carbazole moiety. Furthermore, this novel chemosensor was employed for a comparative study of real environmental samples of airbone particulate matter collected from Dunkirk (Northern of France). Among selected relevant metal cations present in its airbone particulate matter, such as Na(+), K(+), Mg(2+), Ca(2+), Al(3+), Cr(3+), Mn(2+) and Zn(2+), this molecular device proved to be outstandingly sensitive toward Fe(3+) with a limit of detection of 1.49 ppb (2.1×10(-8) M) in methanol allowing the estimation of total iron in atmospheric particles. Copyright © 2015 Elsevier B.V. All rights reserved.

Distribution and Multivariate Pollution Risks Assessment of Heavy Metals and Natural Radionuclides Around Abandoned Iron-Ore Mines in North Central Nigeria

NASA Astrophysics Data System (ADS)

Isinkaye, Omoniyi Matthew

2018-02-01

The Itakpe abandoned iron-ore mines constitute the largest iron-ore deposits in Nigeria with an estimated reserve of about three million metric tons of ore. The present effort is a part of a comprehensive study to estimate the environmental and radiological health hazards associated with previous mining operations in the study area. In this regard, heavy metals (Fe, Zn, Cu, Cd, Cr, Mn, Pb, Ni, Co and As) and natural radionuclides (U, Th and K) were measured in rock, soil and water samples collected at different locations within the mining sites. Atomic absorption and gamma-ray spectrometry were utilized for the measurements. Fe, Mn, Zn, Cu, Ni, Cd, Cr, Co Pb and As were detected at varying concentrations in rock and soil samples. Cd, Cr, Pb and As were not detected in water samples. The concentrations of heavy metals vary according to the following pattern; rock ˃ soil ˃ water. The mean elemental concentrations of K, U and Th are 2.9%, 0.8 and 1.2 ppm and 1.3%, 0.7 and 1.7 ppm, respectively, for rock and soil samples. Pearson correlation analyses of the results indicate that the heavy metals are mostly negatively correlated with natural radionuclides in the study area. Cancer and non-cancer risks due to heavy metals and radiological hazards due to natural radionuclides to the population living within the vicinity of the abandoned mines are lower than acceptable limits. It can, therefore, be concluded that no significant environmental or radiological health hazard is envisaged.

Characterization of 68Zn uptake, translocation, and accumulation into developing grains and young leaves of high Zn-density rice genotype*

PubMed Central

Wu, Chun-yong; Feng, Ying; Shohag, Md. Jahidul Islam; Lu, Ling-li; Wei, Yan-yan; Gao, Chong; Yang, Xiao-e

2011-01-01

Zinc (Zn) is an essential micronutrient for humans, but Zn deficiency has become serious as equally as iron (Fe) and vitamin A deficiencies nowadays. Selection and breeding of high Zn-density crops is a suitable, cost-effective, and sustainable way to improve human health. However, the mechanism of high Zn density in rice grain is not fully understood, especially how Zn transports from soil to grains. Hydroponics experiments were carried out to compare Zn uptake and distribution in two different Zn-density rice genotypes using stable isotope technique. At seedling stage, IR68144 showed higher 68Zn uptake and transport rate to the shoot for the short-term, but no significant difference was observed in both genotypes for the long-term. Zn in xylem sap of IR68144 was consistently higher, and IR68144 exhibited higher Zn absorption ratio than IR64 at sufficient (2.0 µmol/L) or surplus (8.0 µmol/L) Zn supply level. IR64 and IR68144 showed similar patterns of 68Zn accumulation in new leaves at seedling stage and in developing grains at ripening stage, whereas 68Zn in new leaves and grains of IR68144 was consistently higher. These results suggested that a rapid root-to-shoot translocation and enhanced xylem loading capacity may be the crucial processes for high Zn density in rice grains. PMID:21528496

Assessment of metal contents in spices and herbs from Saudi Arabia.

PubMed

Seddigi, Z S; Kandhro, G A; Shah, F; Danish, E; Soylak, Mustafa

2016-02-01

In the recent years, there has been a growing interest in monitoring heavy metal contamination of spices/herbs. Spices and herbs are sources of many bioactive compounds that can improve the tastes of food as well as influence digestion and metabolism processes. In the present study, the levels of some essential and toxic elements such as iron (Fe), zinc (Zn), copper (Cu), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), lead (Pb), and cadmium (Cd), present in common spices/herbs that were purchased from the local market in Saudi Arabia, were analyzed by atomic absorption spectroscopy after digestion with nitric acid/hydrogen peroxide mixture. Samples from the following spices/herbs were used: turmeric, cloves, black pepper, red pepper, cumin, legume, cinnamon, abazir, white pepper, ginger, and coriander. The concentration ranges for the studied elements were found as 48.8-231, 4.7-19.4, 2.5-10.5, below detection level (BDL)-1.0, 8.8-490, 1.0-2.6, and BDL-3.7 µg g(-1) for Fe, Zn, Cu, Cr, Mn, Ni, and Pb, respectively, while Cd and Co levels were below the detection limit. Consumers of these spices/herbs would not be exposed to any risk associated with the daily intake of 10 g of spices per day as far as metals Fe, Zn, Cu, Cr, Mn, Ni, and Pb are concerned. © The Author(s) 2013.

Effect of annealing temperature and copper mole ratio on the morphology, structure and magnetic properties of Mg0.5-xCuxZn0.5Fe2O4 nanoparticles prepared by the modified Pechini method

NASA Astrophysics Data System (ADS)

Loghman-Estarki, M. R.; Torkian, S.; Rastabi, R. Amini; Ghasemi, A.

2017-11-01

In this study, magnesium copper zinc ferrite (MCZ) nanoparticles were synthesized by the modified Pechini method. In this approach, the magnesium nitrate, copper nitrate, zinc nitrate, iron nitrate, citric acid and diethylene glycol (instead of ethylene glycol in conventional Pechini method) were used as a source of Mg2+, Cu2+, Zn2+, complex and stabilizer and solvent agent, respectively. The effect of annealing temperature and copper mole ratio on the morphology, structural and magnetic properties of Mg0.5xCuxZn0.5Fe2O4 (x = 0-0.5) nanoparticles were investigated. Various characterization methods, including X-ray diffraction (XRD), field emission scanning electron microscope (FeSEM), energy-dispersive spectroscopy (EDS), X-ray mapping, Fourier transforms infrared spectroscopy (FTIR), adsorption-desorption isotherm and vibrating sample magnetometer (VSM) were used to study the phase, microstructure, particle size, elemental distribution, functional group determination, porosity and magnetic properties of nanoparticles, respectively. The results showed that cubic spinel phase with various morphologies such as semi-spherical, sheet-like shapes was obtained by the modified Pechini method. Furthermore, the nanoparticles with the x value of 0.2, annealed at 700 °C have the highest saturation magnetization (Ms = 56.5 emu/g) among the other synthesized MCZ ferrite nanoparticles.

Trace element inhibition of phytase activity.

PubMed

Santos, T; Connolly, C; Murphy, R

2015-02-01

Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p < 0.001 was verified. The proteinate sources of OTMs were consistently and significantly less inhibitory than the majority of the other sources, p < 0.05. This was verified for Escherichia coli and Peniophora lycii phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

Novel fabrication of a robust superhydrophobic PU@ZnO@Fe3O4@SA sponge and its application in oil-water separations.

PubMed

Tran, Viet-Ha Thi; Lee, Byeong-Kyu

2017-12-13

We report a novel superhydrophobic material based on commercially available polyurethane (PU) sponge with high porosity, low density and good elasticity. The fabrication of a superhydrophobic sponge capable of efficiently separating oil from water was achieved by imitating or mimicking nature's designs. The original PU sponge was coated with zinc oxide (ZnO), stearic acid (SA) and iron oxide particles (Fe 3 O 4 ) via a facile and environmentally friendly method. After each treatment, the properties of the modified sponge were characterized, and the changes in wettability were examined. Water contact angle (WCA) measurements confirmed the excellent superhydrophobicity of the material withhigh static WCA of 161° andlow dynamic WCA (sliding WCA of 7° and shedding WCA of 8°). The fabricated sponge showed high efficiency in separation (over 99%) of different oils from water. Additionally, the fabricated PU@ZnO@Fe 3 O 4 @SA sponge could be magnetically guided to quickly absorb oil floating on the water surface. Moreover, the fabricated sponge showed excellent stability and reusability in terms of superhydrophobicity and oil absorption capacity. The durable, magnetic and superhydrophobic properties of the fabricated sponge render it applicable to the cleanup of marine oil spills and other oil-water separation issues, with eco-friendly recovery of the oil by simple squeezing process.

Promotive effects of resistant maltodextrin on apparent absorption of calcium, magnesium, iron and zinc in rats.

PubMed

Miyazato, Shoko; Nakagawa, Chie; Kishimoto, Yuka; Tagami, Hiroyuki; Hara, Hiroshi

2010-04-01

It has been reported that low-viscous and fermentable dietary fiber and nondigestible oligosaccharides enhance mineral absorption. Resistant maltodextrin, nonviscous, fermentable and soluble source of dietary fiber, has several physiological functions. However, influence of resistant maltodextrin on mineral absorption is unclear. We conducted balance studies in rats to investigate effects of resistant maltodextrin and hydrogenated resistant maltodextrin on apparent mineral absorption. In experiment 1 (Exp. 1), 40 rats were fed test diets based on AIN-93G with or without resistant maltodextrin or hydrogenated resistant maltodextrin for 2 weeks. In experiment 2 (Exp. 2), 32 rats were cecectomized (CX) or sham-operated (Sham) and fed diets with or without hydrogenated resistant maltodextrin for 1 week. In Exp. 1, ingestion of resistant maltodextrin and hydrogenated resistant maltodextrin dose-dependently enhanced apparent absorption rates of Ca, Mg, Fe and Zn, and increased cecal fermentation with cecal expansion. In Exp. 2, the absorption rates of Ca and Mg were significantly enhanced by ingestion of hydrogenated resistant maltodextrin in Sham group but not in CX group. The promotion of Fe and Zn absorption was not affected by cecectomy. Ingestion of resistant maltodextrin and hydrogenated resistant maltodextrin increased apparent Ca and Mg absorptions dependent on cecal fermentation, while other mechanisms may also be involved in promotion of apparent Fe and Zn absorption by resistant maltodextrin.

The effect of dietary zinc - and polyphenols intake on DMBA-induced mammary tumorigenesis in rats

PubMed Central

2012-01-01

Background The aim of the study was to investigate the effect of dietary supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein, on the effectiveness of chemically induced mammary cancer and the changes in the content of selected elements (Zn, Cu, Mg, Fe, Ca) in tumors as compared with normal tissue of the mammary gland. Methods Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet and DMBA (7,12-dimethyl-1,2- benz[a]anthracene), were treated with zinc ions (Zn) or zinc ions + resveratrol (Zn + resveratrol) or zinc ions + genistein (Zn + genistein) via gavage for a period from 40 days until 20 weeks of age. The ICP-OES (inductively coupled plasma optical emission spectrometry) technique was used to analyze the following elements: magnesium, iron, zinc and calcium. Copper content in samples was estimated in an atomic absorption spectrophotometer. Results Regardless of the diet (standard; Zn; Zn + resveratrol; Zn + genistein), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn + resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. On the basis of quantitative analysis of selected elements we found - irrespectively of the diet applied - great accumulation of copper and iron, which are strongly prooxidative, with a simultaneous considerable decrease of the magnesium content in DMBA-induced mammary tumors. The combination of zinc supplementation with resveratrol resulted in particularly large differences in the amount of the investigated elements in tumors as compared with their content in normal tissue. Conclusions Diet supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein had no effect on the decreased copper level in tumor tissue and inhibited mammary carcinogenesis in the rat. Irrespectively of the applied diet, the development of the neoplastic process in rats resulted in changes of the iron and magnesium content in the cancerous tissue in comparison with the healthy mammary tissue. The application of combined diet supplementation with zinc ions and resveratrol considerably promoted the rate of carcinogenesis and increased the number of DMBA-induced mammary tumors. PMID:22507225

Cloning and characterization of iron-superoxide dismutase in Antarctic yeast strain Rhodotorula mucilaginosa AN5.

PubMed

Kan, Guangfeng; Wen, Hua; Wang, Xiaofei; Zhou, Ting; Shi, Cuijuan

2017-08-01

A novel superoxide dismutase gene from Antarctic yeast Rhodotorula mucilaginosa AN5 was cloned, sequenced, and then expressed in Escherichia coli. The R. mucilaginosa AN5 SOD (RmFeSOD) gene was 639 bp open reading frame in length, which encoded a protein of 212 amino acids with a deduced molecular mass of 23.5 kDa and a pI of 7.89. RmFeSOD was identified as iron SOD type with a natural status of homodimer. The recombinant RmFeSOD showed good pH stability in the pH 1.0-9.0 after 1 h incubation. Meanwhile, it was found to behave relatively high thermostability, and maintained more than 80% activity at 50 °C for 1 h. By addition of 1 mM metal ions, the enzyme activity increased by Zn 2+ , Cu 2+ , Mn 2+ , and Fe 3+ , and inhibited only by Mg 2+ . RmFeSOD showed relatively low tolerance to some compounds, such as PMSF, SDS, Tween-80, Triton X-100, DMSO, β-ME, and urea. However, DTT showed no inhibition to enzyme activity. Using copper stress experiment, the RmFeSOD recombinant E. coli exhibited better growth than non-recombinant bacteria, which revealed that RmFeSOD might play an important role in the adaptability of heavy metals. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of pasteurization on trace elements in donor breast milk.

PubMed

Mohd-Taufek, N; Cartwright, D; Davies, M; Hewavitharana, A K; Koorts, P; McConachy, H; Shaw, P N; Sumner, R; Whitfield, K

2016-10-01

Premature infants often receive pasteurized donor human milk when mothers are unable to provide their own milk. This study aims to establish the effect of the pasteurization process on a range of trace elements in donor milk. Breast milk was collected from 16 mothers donating to the milk bank at the Royal Brisbane and Women's Hospital. Samples were divided into pre- and post-pasteurization aliquots and were Holder pasteurized. Inductively coupled plasma mass spectrometry was used to analyze the trace elements zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), iodine (I), iron (Fe), molybdenum (Mo) and bromine (Br). Differences in trace elements pre- and post-pasteurization were analyzed. No significant differences were found between the trace elements tested pre- and post-pasteurization, except for Fe (P<0.05). The median (interquartile range, 25 to 75%; μg l(-1)) of trace elements for pre- and post- pasteurization aliquots were-Zn: 1639 (888-4508), 1743 (878-4143), Cu: 360 (258-571), 367 (253-531), Se: 12.34 (11.73-17.60), 12.62 (11.94-16.64), Mn: (1.48 (1.01-1.75), 1.49 (1.11-1.75), I (153 (94-189), 158 (93-183), Fe (211 (171-277), 194 (153-253), Mo (1.46 (0.37-2.99), 1.42 (0.29-3.73) and Br (1066 (834-1443), 989 (902-1396). Pasteurization had minimal effect on several trace elements in donor breast milk but high levels of inter-donor variability of trace elements were observed. The observed decrease in the iron content of pasteurized donor milk is, however, unlikely to be clinically relevant.

The variability in iron speciation in size fractionated residual oil fly ash particulate matter (ROFA PM).

PubMed

Pattanaik, Sidhartha; Huggins, Frank E; Huffman, Gerald P

2016-08-15

Ambient particulate matter (PM) containing iron can catalyze Fenton reaction leading to the production of reactive oxygen species in cells. It can also catalyze atmospheric redox reaction. These reactions are governed by the physicochemical characteristics of iron in ambient PM. As a surrogate for ambient PM, we prepared residual oil fly ash PM (ROFA PM) in a practical fire tube boiler firing residual oils with varying sulfur and ash contents. The ROFA particles were resolved into fine PM or PM2.5 (aerodynamic diameter (AD)<2.5μm) and coarse PM or PM2.5+ (AD between 2.5μm and 50μm). The iron speciation in PM2.5+ was ascertained using X-ray absorption spectroscopy and leaching method while that in PM2.5 was reported earlier. The results of both studies are compared to get an insight into the variability in the iron speciation in different size fractions. The results show the predominance of ferric sulfate, with a minor spinal ferrite in both PM (i.e. ZnxNi1-xFe2O4 in PM2.5, ZnFe2O4 in PM2.5+). The iron solubility in ROFA PM depends on its speciation, mode of incorporation of iron into particle's carbonaceous matrix, the grade and composition of oils, and pH of the medium. The soluble fraction of iron in PM is critical in assessing its interaction with the biological systems and its toxic potential. Copyright © 2016 Elsevier B.V. All rights reserved.

Coordinatively Unsaturated Metal-Organic Frameworks M3(btc)2 (M = Cr, Fe, Co, Ni, Cu, and Zn) Catalyzing the Oxidation of CO by N2O: Insight from DFT Calculations.

PubMed

Ketrat, Sombat; Maihom, Thana; Wannakao, Sippakorn; Probst, Michael; Nokbin, Somkiat; Limtrakul, Jumras

2017-11-20

The oxidation of CO by N 2 O over metal-organic framework (MOF) M 3 (btc) 2 (M = Fe, Cr, Co, Ni, Cu, and Zn) catalysts that contain coordinatively unsaturated sites has been investigated by means of density functional theory calculations. The reaction proceeds in two steps. First, the N-O bond of N 2 O is broken to form a metal oxo intermediate. Second, a CO molecule reacts with the oxygen atom of the metal oxo site, forming one C-O bond of CO 2 . The first step is a rate-determining step for both Cu 3 (btc) 2 and Fe 3 (btc) 2 , where it requires the highest activation energy (67.3 and 19.6 kcal/mol, respectively). The lower value for the iron compound compared to the copper one can be explained by the larger amount of electron density transferred from the catalytic site to the antibonding of N 2 O molecules. This, in turn, is due to the smaller gap between the highest occupied molecular orbital (HOMO) of the MOF and the lowest unoccupied molecular orbital (LUMO)  of N 2 O for Fe 3 (btc) 2 compared to Cu 3 (btc) 2 . The results indicate the important role of charge transfer for the N-O bond breaking in N 2 O. We computationally screened other MOF M 3 (btc) 2 (M = Cr, Fe, Co, Ni, Cu, and Zn) compounds in this respect and show some relationships between the activation energy and orbital properties like HOMO energies and the spin densities of the metals at the active sites of the MOFs.

Human and animal health risk assessment of metal contamination in soil and plants from Ait Ammar abandoned iron mine, Morocco.

PubMed

Nouri, Mohamed; Haddioui, Abdelmajid

2016-01-01

The goal of this paper is to investigate metal pollution in food chain and assess the resulting health risks to native citizens in Ait Ammar village. The results showed that cadmium (Cd), lead (Pb), and copper (Cu) concentrations in animal organs were above the metal concentration safety limit. Nevertheless, soils and plants from mining area were contaminated with iron (Fe), chromium (Cr), zinc (Zn), and Cr, Cu, Zn respectively. Cd concentrations in almost animal organs were higher than the acceptable daily upper limit, suggesting human consumption of this livestock meat and offal may pose a health risk. The estimated intake of Pb and Cd for Ait Ammar population could be a cause of concern because it exceeded the Provisional Tolerable Weekly Intake (PTWI) proposed by Joint Expert Committee on Food Additives (JECFA) in this area. Thus, conducting regular periodic studies to assess the dietary intake of mentioned elements are recommended.

Determination of Serum Trace Elements (Zn, Cu, and Fe) in Pakistani Patients with Rheumatoid Arthritis.

PubMed

Ullah, Zia; Ullah, Muhammad Ikram; Hussain, Shabbir; Kaul, Haiba; Lone, Khalid P

2017-01-01

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease, which mainly involves the joints. RA is prevalent worldwide with increasing prevalence in elderly people. The mechanism of RA pathogenesis is still undefined, and it is interplaying between genetic susceptibility and environmental factors. Although risk factors for RA are not fully established, various studies have focused on the role of trace elements in association with RA. Trace elements act as co-factors for most of the enzymes, and their deficiency is associated with many untoward effects on human health. The homeostatic alterations in the metabolism of trace elements may partly be due to inflammatory response in RA. The objective of the present study was to determine the serum concentrations and correlation of zinc, copper, and iron in RA patients and healthy controls. The study comprised of 61 RA patients and 61 age- and sex-related healthy individuals of Pakistani population. Serum levels of Zn, Cu, and Fe were measured in all the participants by atomic absorption spectrophotometer. Serum Zn and Fe were significantly reduced in the RA patients than those in the healthy controls. Serum Cu concentrations were found elevated in the RA patients. Correlation studies of trace elements determine that there was negative correlation between Zn and Cu in the RA patients and no correlation in the control group. It is very important to explore the deficiency of essential trace metals in biological samples of the RA patients in different populations which may be helpful for diagnosis and supplementary management of rheumatoid arthritis patients.

Design of Super-Paramagnetic Core-Shell Nanoparticles for Enhanced Performance of Inverted Polymer Solar Cells.

PubMed

Jaramillo, Johny; Boudouris, Bryan W; Barrero, César A; Jaramillo, Franklin

2015-11-18

Controlling the nature and transfer of excited states in organic photovoltaic (OPV) devices is of critical concern due to the fact that exciton transport and separation can dictate the final performance of the system. One effective method to accomplish improved charge separation in organic electronic materials is to control the spin state of the photogenerated charge-carrying species. To this end, nanoparticles with unique iron oxide (Fe3O4) cores and zinc oxide (ZnO) shells were synthesized in a controlled manner. Then, the structural and magnetic properties of these core-shell nanoparticles (Fe3O4@ZnO) were tuned to ensure superior performance when they were incorporated into the active layers of OPV devices. Specifically, small loadings of the core-shell nanoparticles were blended with the previously well-characterized OPV active layer of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Upon addition of the core-shell nanoparticles, the performance of the OPV devices was increased up to 25% relative to P3HT-PCBM active layer devices that contained no nanoparticles; this increase was a direct result of an increase in the short-circuit current densities of the devices. Furthermore, it was demonstrated that the increase in photocurrent was not due to enhanced absorption of the active layer due to the presence of the Fe3O4@ZnO core-shell nanoparticles. In fact, this increase in device performance occurred because of the presence of the superparamagnetic Fe3O4 in the core of the nanoparticles as incorporation of ZnO only nanoparticles did not alter the device performance. Importantly, however, the ZnO shell of the nanoparticles mitigated the negative optical effect of Fe3O4, which have been observed previously. This allowed the core-shell nanoparticles to outperform bare Fe3O4 nanoparticles when the single-layer nanoparticles were incorporated into the active layer of OPV devices. As such, the new materials described here present a tangible pathway toward the development of enhanced design schemes for inorganic nanoparticles such that magnetic and energy control pathways can be tailored for flexible electronic applications.

mRNA Levels of Placental Iron and Zinc Transporter Genes Are Upregulated in Gambian Women with Low Iron and Zinc Status.

PubMed

Jobarteh, Modou Lamin; McArdle, Harry J; Holtrop, Grietje; Sise, Ebrima A; Prentice, Andrew M; Moore, Sophie E

2017-07-01

Background: The role of the placenta in regulating micronutrient transport in response to maternal status is poorly understood. Objective: We investigated the effect of prenatal nutritional supplementation on the regulation of placental iron and zinc transport. Methods: In a randomized trial in rural Gambia [ENID (Early Nutrition and Immune Development)], pregnant women were allocated to 1 of 4 nutritional intervention arms: 1 ) iron and folic acid (FeFol) tablets (FeFol group); 2 ) multiple micronutrient (MMN) tablets (MMN group); 3 ) protein energy (PE) as a lipid-based nutrient supplement (LNS; PE group); and 4 ) PE and MMN (PE+MMN group) as LNS. All arms included iron (60 mg/d) and folic acid (400 μg/d). The MMN and PE+MMN arms included 30 mg supplemental Zn/d. In a subgroup of ∼300 mother-infant pairs, we measured maternal iron status, mRNA levels of genes encoding for placental iron and zinc transport proteins, and cord blood iron levels. Results: Maternal plasma iron concentration in late pregnancy was 45% and 78% lower in the PE and PE+MMN groups compared to the FeFol and MMN groups, respectively ( P < 0.001). The mRNA levels of the placental iron uptake protein transferrin receptor 1 were 30-49% higher in the PE and PE+MMN arms than in the FeFol arm ( P < 0.031), and also higher in the PE+MMN arm (29%; P = 0.042) than in the MMN arm. Ferritin in infant cord blood was 18-22% lower in the LNS groups ( P < 0.024). Zinc supplementation in the MMN arm was associated with higher maternal plasma zinc concentrations (10% increase; P < 0.001) than in other intervention arms. mRNA levels for intracellular zinc-uptake proteins, in this case zrt, irt-like protein (ZIP) 4 and ZIP8, were 96-205% lower in the PE+MMN arm than in the intervention arms without added zinc ( P < 0.025). Furthermore, mRNA expression of ZIP1 was 85% lower in the PE+MMN group than in the PE group ( P = 0.003). Conclusion: In conditions of low maternal iron and in the absence of supplemental zinc, the placenta upregulates the gene expression of iron and zinc uptake proteins, presumably in order to meet fetal demands in the face of low maternal supply. The ENID trial was registered at www.controlled-trials.com as ISRCTN49285450.

Differential Effects of Low-Molecular-Weight Organic Acids on the Mobilization of Soil-Borne Arsenic and Trace Metals.

PubMed

Nworie, Obinna Elijah; Qin, Junhao; Lin, Chuxia

2017-08-21

A batch experiment was conducted to examine the effects of six low-molecular-weight organic acids on the mobilization of arsenic and trace metals from a range of contaminated soils. The results showed that the organic acids behaved differently when reacting with soil-borne As and trace metals. Oxalic acid and acetic acid had the strongest and weakest capacity to mobilize the investigated elements, respectively. The solubilisation of iron oxides by the organic acids appears to play a critical role in mobilizing other trace metals and As. Apart from acidification and complexation, reductive dissolution played a dominant role in the dissolution of iron oxides in the presence of oxalic acid, while acidification tended to be more important for dissolving iron oxides in the presence of other organic acids. The unique capacity of oxalic acid to solubilize iron oxides tended to affect the mobilization of other elements in different ways. For Cu, Mn, and Zn, acidification-driven mobilization was likely to be dominant while complexation might play a major role in Pb mobilization. The formation of soluble Fe and Pb oxalate complexes could effectively prevent arsenate or arsenite from combining with these metals to form solid phases of Fe or Pb arsenate or arsenite.

Novel multifunctional NiFe2O4/ZnO hybrids for dye removal by adsorption, photocatalysis and magnetic separation

NASA Astrophysics Data System (ADS)

Zhu, Hua-Yue; Jiang, Ru; Fu, Yong-Qian; Li, Rong-Rong; Yao, Jun; Jiang, Sheng-Tao

2016-04-01

Novel multifunctional NiFe2O4/ZnO hybrids were prepared by a hydrothermal method and their physicochemical properties were characterized by XRD, SEM, TEM, TGA, VSM, BET and UV-vis DRS. The adsorption and photocatalytic performance of NiFe2O4/ZnO hybrids were systematically investigated using congo red as a model contaminant. With the introduction of NiFe2O4, NiFe2O4/ZnO hybrids can absorb the whole light from 300 nm to 700 nm. The adsorption capacity (221.73 mg g-1) of NiFe2O4/ZnO hybrids is higher than those of NiFe2O4, ZnO and mechanically mixed NiFe2O4/ZnO hybrids. The removal of congo red solution (20 mg L-1) by NiFe2O4/ZnO hybrids was about 94.55% under simulated solar light irradiation for 10 min. rad OH and h+ play important roles in the decolorization of congo red solution by NiFe2O4/ZnO hybrids under simulated solar light irradiation. The decolorization efficiency of congo red solution is 97.23% for the fifth time by NiFe2O4/ZnO hybrids under simulate solar light irradiation, indicating the high photostability and durability. NO3- and Cl- anions which are ubiquitous components in dye-containing wastewater have negligible influence on the effectiveness of NiFe2O4/ZnO hybrids. Moreover, the magnetic NiFe2O4/ZnO hybrids can be easily separated from the reacted solution by an external magnet.

Too much is bad--an appraisal of phytotoxicity of elevated plant-beneficial heavy metal ions.

PubMed

Anjum, Naser A; Singh, Harminder P; Khan, M Iqbal R; Masood, Asim; Per, Tasir S; Negi, Asha; Batish, Daizy R; Khan, Nafees A; Duarte, Armando C; Pereira, Eduarda; Ahmad, Iqbal

2015-03-01

Heavy metal ions such as cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn) are considered essential/beneficial for optimal plant growth, development, and productivity. However, these ions readily impact functions of many enzymes and proteins, halt metabolism, and exhibit phytotoxicity at supra-optimum supply. Nevertheless, the concentrations of these heavy metal ions are increasing in agricultural soils worldwide via both natural and anthropogenic sources that need immediate attention. Considering recent breakthroughs on Co, Cu, Fe, Mn, Mo, Ni, and Zn in soil-plant system, the present paper: (a) overviews the status in soils and their uptake, transport, and significance in plants; (b) critically discusses their elevated level-mediated toxicity to both plant growth/development and cell/genome; (c) briefly cross talks on the significance of potential interactions between previous plant-beneficial heavy metal ions in plants; and (d) highlights so far unexplored aspects in the current context.

A proposed magnetic digital temperature transducer, volume 1

NASA Technical Reports Server (NTRS)

Collier, T. E.; Tchernev, D. I.; Hartwig, W. H.

1972-01-01

A study has been made of the feasibility of using the discontinuous permeability versus temperature characteristics of some magnetic materials for a digital temperature transducer and a thermally controlled ON-OFF switch. Simple logic converts the number of output pulse to a digital word recognizable by the system. Efforts have been concentrated on materials with Curie temperatures between 0 and 100 C. One compound has the composition Mn(5-x)Fe(x)Ge3 where the amount of iron determines the transition temperature. The other compound is Ni-Zn ferrite and has the compositon Ni(1-x)Zn(x)Fe(1.95)O4 where the nickel: zinc ratio determines the transition temperature. A detailed report of materials prepared is presented. Toroidal inductors of the material have been constructed and the change in inductance with temperature measured. In view of these initial measurements, it is felt that a transducer utilizing the permeability versus temperature characteristics of these materials has promise as a reliable and sensitive solid state digital temperature transducer.

Age-dependent accumulation of heavy metals in a pod of killer whales (Orcinus orca) stranded in the northern area of Japan.

PubMed

Endo, Tetsuya; Kimura, Osamu; Hisamichi, Yohsuke; Minoshima, Yasuhiko; Haraguchi, Koichi

2007-02-01

Mercury (Hg), cadmium (Cd), iron (Fe) manganese (Mn), zinc (Zn) and copper (Cu) concentrations in the liver, kidney and muscle of nine killer whales (including three calves) that stranded together in the northern area of Japan were determined. The Hg and Cd concentrations were found at trace levels in the calf organs, and increased with age. The Fe concentration in the muscle was significantly lower in the calves than in the mature whales and also increased with age. In contrast, Mn and Cu concentrations in the muscle were significantly higher in the calves than in the mature whales, and changes in the Zn concentration relative to age were unclear. These results suggest minimal mother-to-calf transfer of the toxic metals Hg and Cd and accumulation of these metals in the organs with age, while the essential metals Mn and Cu were found at higher concentrations in the muscle of calves than in mature whales.

Concentrations of Heavy Metals in Sardinella gibbosa (Bleeker, 1849) from the Coast of Balochistan, Pakistan.

PubMed

Ahmed, Quratulan; Benzer, Semra; Elahi, Naeema; Ali, Qadeer Mohammad

2015-08-01

The concentrations of cadmium, iron, lead, manganese, nickel, and zinc in muscle tissue samples taken from Goldstripe sardinella (Sardinella gibbosa Bleeker, 1849) caught off the coast of Balochistan, Pakistan, in 2009 were determined. The samples were analyzed using a Perkin Elmer AAnalyst 700 flame atomic absorption spectrophotometer. The mean Cd, Fe, Mn, Ni, Pb, and Zn concentrations in the muscle samples were 0.65±0.05 µg g(-1), 23.39±1.97 µg g(-1), 4.35±0.22 µg g(-1), 0.61±0.07 µg g(-1), 0.39±0.04 µg g(-1), and 6.59±0.33 µg g(-1), respectively. The Cd, Fe, Pb, and Zn concentrations did not exceed the regulatory limits, but the Mn concentrations were high enough to potentially pose health risks to humans consuming S. gibbosa. Therefore, the Mn concentrations in S. gibbosa from the Balochistan coast should be monitored regularly.

Chemoselectivity-induced multiple interfaces in MWCNT/Fe3O4@ZnO heterotrimers for whole X-band microwave absorption.

PubMed

Wang, Zhijiang; Wu, Lina; Zhou, Jigang; Jiang, Zhaohua; Shen, Baozhong

2014-11-07

A chemoselective route to induce Fe3O4@ZnO core-shell nanoparticles decorating carbon nanotubes to form MWCNT/Fe3O4@ZnO heterotrimers has been developed. Charges are redistributed in the heterotrimers through C-O-Zn, C-O-Fe and Fe-O-Zn bondings, giving rise to multiple electronic phases. The generated significant interfacial polarization and synergetic interaction between dielectric and magnetic absorbers result in the MWCNT/Fe3O4@ZnO heterotrimers with high-performance microwave absorption in an entire X band.

Synthesis of magnetic Bi2O2CO3/ZnFe2O4 composite with improved photocatalytic activity and easy recyclability

NASA Astrophysics Data System (ADS)

Liu, Yumin; Ren, Hao; Lv, Hua; Guang, Jing; Cao, Yafei

2018-03-01

Magnetic Bi2O2CO3/ZnFe2O4 heterojunction photocatalysts with varying content of ZnFe2O4 were constructed by modifying Bi2O2CO3 nanosheets with mesoporous ZnFe2O4 nanoparticles. The photoactivity of the products was investigated by decomposing RhodamineB (RhB) and it was found that the photoactivity of Bi2O2CO3/ZnFe2O4 composite was closely related to the loading amount of ZnFe2O4. Under simulant sunlight irradiation, the optimum photoactivity of Bi2O2CO3/ZnFe2O4 composite was almost 2.3 and 2.1 times higher than that by bare ZnFe2O4 and Bi2O2CO3, respectively. The improved photoactivity resulted from the synergistic effect of Bi2O2CO3 and ZnFe2O4, which not only extended the photoabsorption region but also significantly facilitated the interfacial charge transfer. Besides the high photocatalytic performance, Bi2O2CO3/ZnFe2O4 composite also exhibited excellent stable and recycling properties, which enabled it have great potential in a long-term practical use.

Nickel-based rechargeable batteries

NASA Astrophysics Data System (ADS)

Shukla, A. K.; Venugopalan, S.; Hariprakash, B.

Nickel-iron (Ni-Fe), nickel-cadmium (Ni-Cd), nickel-hydrogen (Ni-H 2), nickel-metal hydride (Ni-MH) and nickel-zinc (Ni-Zn) batteries employ nickel oxide electrodes as the positive plates, and are hence, categorised as nickel-based batteries. This article highlights the operating principles and advances made in these battery systems during the recent years. In particular, significant improvements have been made in the Ni-MH batteries which are slowly capturing the market occupied by the ubiquitous Ni-Cd batteries.

Method for carbon dioxide splitting

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

Miller, James E.; Diver, Jr., Richard B.; Siegel, Nathan P.

A method for splitting carbon dioxide via a two-step metal oxide thermochemical cycle by heating a metal oxide compound selected from an iron oxide material of the general formula A.sub.xFe.sub.3-xO.sub.4, where 0.ltoreq.x.ltoreq.1 and A is a metal selected from Mg, Cu, Zn, Ni, Co, and Mn, or a ceria oxide compound of the general formula M.sub.aCe.sub.bO.sub.c, where 0

Comparative Assessment of Copper, Iron, and Zinc Contents in Selected Indian (Assam) and South African (Thohoyandou) Tea (Camellia sinensis L.) Samples and Their Infusion: A Quest for Health Risks to Consumer.

PubMed

Karak, Tanmoy; Paul, Ranjit Kumar; Kutu, Funso Raphael; Mehra, Aradhana; Khare, Puja; Dutta, Amrit Kumar; Bora, Krishnamoni; Boruah, Romesh Kumar

2017-02-01

The current study aims to assess the infusion pattern of three important micronutrients namely copper (Cu), iron (Fe), and zinc (Zn) contents from black tea samples produced in Assam (India) and Thohoyandou (South Africa). Average daily intakes and hazardous quotient were reported for these micronutrients. Total content for Cu, Fe, and Zn varied from 2.25 to 48.82 mg kg -1 , 14.75 to 148.18 mg kg -1 , and 28.48 to 106.68 mg kg -1 , respectively. The average contents of each of the three micronutrients were higher in tea leaves samples collected from South Africa than those from India while the contents in tea infusions in Indian samples were higher than in South African tea samples. Results of this study revealed that the consumption of 600 mL tea infusion produced from 24 g of made tea per day may be beneficial to human in terms of these micronutrients content. Application of nonparametric tests revealed that most of the data sets do not satisfy the normality assumptions. Hence, the use of both parametric and nonparametric statistical analysis that subsequently revealed significant differences in elemental contents among Indian and South African tea.

Ring head recording on perpendicular media: Output spectra for CoCr and CoCr/NiFe media

NASA Astrophysics Data System (ADS)

Stubbs, D. P.; Whisler, J. W.; Moe, C. D.; Skorjanec, J.

1985-04-01

The recording density response for sputtered CoCr (thickness=0.5 μm) and CoCr/NiFe (t=0.25 μm/0.5 μm) as well as evaporated CoNi (t=0.12 μm) and Co surface-doped iron oxide particulate media has been measured by reading and writing with Mn-Zn ferrite heads (gap length=0.375 μm, track width=37 μm) in contact with the media. Measurements to 200 kfc/i (thousand flux changes per inch) show a gap null around 115 kfc/i. The data have been normalized by dividing out the head sensitivity to obtain the value of spacing plus transition width (d+a) for the various media. For the CoCr media this value varied from 0.075-0.088 μm; for CoNi, 0.100 μm, and for the particulate medium, 0.163 μm. In addition, testing with a larger gapped Mn-Zn ferrite head (g=2.43 μm) shows that the head fields are distorted by the soft magnetic underlayer in dual layer CoCr/NiFe samples when the gap length is large compared to the distance to the underlayer.

Mix and match: templating chiral Schiff base ligands to suit the needs of the metal ion.

PubMed

Constable, Edwin C; Zhang, Guoqi; Housecroft, Catherine E; Zampese, Jennifer A

2010-06-14

One-pot reactions of 2,2'-bipyridine-6-carbaldehyde, (1S,2S)-(-)-1,2-diphenyl-1,2-diaminoethane and FeCl(2).4H(2)O or Zn(OAc)(2).2H(2)O (2 : 1 : 1) at room temperature in MeOH lead to [Fe{(S,S)-5}(2)][PF(6)]Cl or [Zn{(S,S)-5}(2)][PF(6)](2) in which (S,S)-5 contains an imidazolidine ring, produced by intramolecular cyclization. This has been confirmed with the single-crystal structure of 2{P-[Fe{(S,S)-5}(2)][PF(6)]Cl}.H(2)O. The diastereoselectivity observed in the solid state has been confirmed by NMR spectroscopy for solutions of [Fe{(S,S)-5}(2)][PF(6)]Cl and [Zn{(S,S)-5}(2)][PF(6)](2). At room temperature, a minor product competes with the formation of [Fe{(S,S)-5}(2)][PF(6)]Cl, and the preference for these complexes is switched by carrying out the reaction in MeOH at reflux. In this case the major product is M-[Fe(2){(S,S)-4}(2)][PF(6)](4) in which (S,S)-4 is the hexadentate Schiff base ligand formed by condensation of two equivalents of 2,2'-bipyridine-6-carbaldehyde with (1S,2S)-(-)-1,2-diphenyl-1,2-diaminoethane; the single-crystal structure of 4{M-[Fe(2){(S,S)-4}(2)][PF(6)](4)}.8Me(2)CO.5MeCN.3H(2)O confirms the assembly of a double helicate. When pyridine-6-carbaldehyde replaces 2,2'-bipyridine-6-carbaldehyde in the iron(II)-templated reaction with (1S,2S)-(-)-1,2-diphenyl-1,2-diaminoethane, the product is [Fe{(S,S)-7}(2)][PF(6)](2) (3 : 2 mixture of diastereoisomers in solution) in which (S,S)-7 is an asymmetrical Schiff base, formed by reaction of only one of the amine groups in (1S,2S)-(-)-1,2-diphenyl-1,2-diaminoethane. The solid state structure of P-[Fe{(S,S)-7}(2)][PF(6)](2).MeCN is presented.

Depressed antioxidant status in pregnant women on iron supplements: pathologic and clinical correlates.

PubMed

Anetor, J I; Ajose, O A; Adeleke, F N; Olaniyan-Taylor, G O; Fasola, F A

2010-08-01

Iron (Fe) remains a commonly prescribed supplement in pregnancy. Its possible pathologic potential is either uncommonly considered or ignored. We determined the antioxidant status in pregnant women with and without Fe supplements. Fifty-eight apparently healthy pregnant women on Fe supplements were selected for the study from the antenatal clinic of the University College Hospital, Ibadan, Nigeria. Fifty-five aged matched pregnant women who were not on Fe from various parishes of the Christ Apostolic Church, Ibadan (non-drug using Christian sect) were randomly selected as controls. Both groups were classified according to the trimesters of pregnancy. The gestational age in both pregnant women on Fe supplements and non-supplement pregnant women was similar. Fruit and vegetables consumption was higher in the supplement than in the non-supplement group (57.2% vs. 37.3%). Anthropometric indices, weight, height, and BMI, were also similar. But while the weight of the Fe supplement group decreased by nearly 3% in the third trimester, it increased by over 10% (p < 0.00) in the non-supplement group in the same period. Serum Fe level was significantly higher in the supplement than the non-supplement group (p < 0.001). In contrast, the levels of the antioxidants, ascorbic acid, copper (Cu), zinc (Zn), and bilirubin were all significantly decreased (p < 0.05, p < 0.001, p < 0.05, and p < 0.05, respectively). Uric acid level though also lower in the supplement group did not reach statistical significance (p > 0.05), while vitamin E was similar in both groups. There was relative stability of all antioxidants except uric acid, which declined from the first to the last trimester in the non-supplement group. The significantly higher Fe level in the second trimester was sustained in the third trimester though to a lesser degree (p < 0.05) and associated with significant decreases in the following antioxidant levels in the supplement group, ascorbic acid, bilirubin, Cu, and Zn (p < 0.02, p < 0.02, p < 0.02, and p < 0.001, respectively). Uric acid and vitamin E though lower in the supplement group were not significantly different. Remarkably, percentage changes between the first and third trimesters revealed that serum Fe increased by over 116% in the Fe supplement group, while it only increased by over 50% in the non-supplement group. This was associated with 23.50% decrease in ascorbate level (p < 0.003) in the supplement group, while it decreased by only 3.70% in the non-supplement group (p > 0.05). Again vitamin E decreased by 17.22% in the supplement group, while it decreased by only 7.30% in the non-supplement group during the period. Uric acid and bilirubin levels decreased by similar proportions during the period, while Zn decreased by 18.55% in the supplement group and by 14.86% in the non-supplement group. In contrast Cu increased by 7.20% in the supplement group, while it increased by only 2.96 in the non-supplement group. Additionally, all the antioxidants in the supplement group except vitamin E, viz, ascorbic acid, bilirubin, Cu, uric acid, and Zn, were significantly inversely correlated with serum Fe level (r - 0.299, p < 0.05, r - 0.278, p < 0.05, r - 0.383, p < 0.05, and r - 0.0369, p < 0.05). These data imply markedly depressed antioxidant status in the Fe supplement pregnant group with attendant oxidative stress (most probably pro-oxidant Fe-induced). This is associated with molecular and cellular damage as well as a number of pathologic and clinical correlates that underlie the exacerbation of morbidity and mortality in maternal and child populations, particularly in the developing countries. This appears to call for serious caution and prior evaluation of antioxidant and Fe status and during the use of Fe supplements in pregnancy for monitoring and prognostic purposes and to avert or ameliorate oxidative stress-induced pathologies in maternal and fetal systems.

Development and evaluation of novel sensing materials for detecting food contamination

NASA Astrophysics Data System (ADS)

Sankaran, Sindhuja

Rapid detection of food-borne volatile organic compounds (VOCs) such as organic acids and alcohols released by bacterial pathogens is being used as an indicator for detecting bacterial contamination in food by our research group. One of our current research thrusts is to develop novel sensors that will be sensitive to specific compounds (at low operating temperature) associated with food safety. This study evaluates two approaches employed to develop sensors for detecting acid and alcohols at low concentrations. Chemoresistive and piezoelectric sensors were developed based on metal oxides and olfactory system based biomaterials, respectively to detect acetic acid, butanol, 3-methyl-1-butanol, 1-pentanol, and 1-hexanol. The metal oxide based sensors were developed by the sol-gel method. A zinc oxide (ZnO) sensor was found to be sensitive to acetic acid with lower detection limit ranging from 13-40 ppm. The three-layered dip-coated gold electrode based ZnO sensors had a LDL of 18 ppm for acetic acid detection. The ZnO-iron oxide (Fe2O3) based nanocomposite sensors were developed to detect butanol operating at 100°C. The 5% Fe/Zn mole ratio based ZnO-Fe2O3 nanocomposite sensors had high correlation coefficients (>0.90) of calibration curves, low butanol LDLs (26 +/- 7 ppm), and lower variation among the sensor responses. The ZnO and ZnO-Fe2O3 nanocomposite sensors showed potential to detect acetic acid and butanol at low concentrations, respectively at 100°C. QCM based olfactory sensors were developed from olfactory receptor and odorant binding protein based sequences to detect low concentrations of acetic acid and alcohols (3-methyl-1-butanol and 1-hexanol), respectively. The average LDLs for acetic acid as well as alcohols detection of the QCM sensors were < 5 ppm. The linear calibration curve based correlation coefficients of the QCM sensors were > 0.80. Finally, a computational simulation based peptide sequences was designed from olfactory receptors and evaluated as sensor material for the detection of alcohols at low concentrations. The results indicated that the QCM sensors exhibited a good sensitivity to 1-hexanol and 1-pentanol with the estimated LDLs in the range of 2-3 ppm and 3-5 ppm, respectively. This research work was successful in developing multiple novel sensing materials to detect alcohols and acid associated with meat contaminations at low concentrations.

Highly exposed Fe-N4 active sites in porous poly-iron-phthalocyanine based oxygen reduction electrocatalyst with ultrahigh performance for air cathode.

PubMed

Anandhababu, Ganesan; Abbas, Syed Comail; Lv, Jiangquan; Ding, Kui; Liu, Qin; Babu, Dickson D; Huang, Yiyin; Xie, Jiafang; Wu, Maoxiang; Wang, Yaobing

2017-02-14

Progress in the development of efficient electrocatalysts for oxygen reduction reactions is imperative for various energy systems such as metal-air batteries and fuel cells. In this paper, an innovative porous two-dimensional (2D) poly-iron-phthalocyanine (PFe-Pc) based oxygen reduction electrocatalyst created with a simple solid-state chemical reaction without pyrolysis is reported. In this strategy, silicon dioxide nanoparticles play a pivotal role in preserving the Fe-N 4 structure during the polymerization process and thereby assist in the development of a porous structure. The new polymerized phthalocyanine electrocatalyst with tuned porous structure, improved specific surface area and more exposed catalytic active sites via the 2D structure shows an excellent performance towards an oxygen reduction reaction in alkaline media. The onset potential (E = 1.033 V) and limiting current density (I = 5.58 mA cm -2 ) are much better than those obtained with the commercial 20% platinum/carbon electrocatalyst (1.046 V and 4.89 mA cm -2 ) and also show better stability and tolerance to methanol crossover. For practical applications, a zinc-air (Zn-air) battery and methanol fuel cell equipped with the PFe-Pc electrocatalyst as an air cathode reveal a high open circuit voltage and maximum power output (1.0 V and 23.6 mW cm -2 for a methanol fuel cell, and 1.6 V and 192 mW cm -2 for the liquid Zn-air battery). In addition, using the PFe-Pc electrocatalyst as an air cathode in a flexible cable-type Zn-air battery exhibits excellent performance with an open-circuit voltage of 1.409 V. This novel porous 2D PFe-Pc has been designed logically using a new, simple strategy with ultrahigh electrochemical performances in Zn-air batteries and methanol fuel cell applications.

Study on the Electrochemical Reaction Mechanism of ZnFe2O4 by In Situ Transmission Electron Microscopy

PubMed Central

Su, Qingmei; Wang, Shixin; Yao, Libing; Li, Haojie; Du, Gaohui; Ye, Huiqun; Fang, Yunzhang

2016-01-01

A family of mixed transition–metal oxides (MTMOs) has great potential for applications as anodes for lithium ion batteries (LIBs). However, the reaction mechanism of MTMOs anodes during lithiation/delithiation is remain unclear. Here, the lithiation/delithiation processes of ZnFe2O4 nanoparticles are observed dynamically using in situ transmission electron microscopy (TEM). Our results suggest that during the first lithiation process the ZnFe2O4 nanoparticles undergo a conversion process and generate a composite structure of 1–3 nm Fe and Zn nanograins within Li2O matrix. During the delithiation process, volume contraction and the conversion of Zn and Fe take place with the disappearance of Li2O, followed by the complete conversion to Fe2O3 and ZnO not the original phase ZnFe2O4. The following cycles are dominated by the full reversible phase conversion between Zn, Fe and ZnO, Fe2O3. The Fe valence evolution during cycles evidenced by electron energy–loss spectroscopy (EELS) techniques also exhibit the reversible conversion between Fe and Fe2O3 after the first lithiation, agreeing well with the in situ TEM results. Such in situ TEM observations provide valuable phenomenological insights into electrochemical reaction of MTMOs, which may help to optimize the composition of anode materials for further improved electrochemical performance. PMID:27306189

Spectroscopic and metal-binding properties of DF3: an artificial protein able to accommodate different metal ions

PubMed Central

Torres Martin de Rosales, Rafael; Faiella, Marina; Farquhar, Erik; Que, Lawrence; Andreozzi, Concetta; Pavone, Vincenzo; Maglio, Ornella; Nastri, Flavia

2010-01-01

The design, synthesis, and metal-binding properties of DF3, a new de novo designed di-iron protein model are described (“DF” represents due ferri, Italian for “two iron,” “di-iron”). DF3 is the latest member of the DF family of synthetic proteins. They consist of helix–loop–helix hairpins, designed to dimerize and form an antiparallel four-helix bundle that encompasses a metal-binding site similar to those of non-heme carboxylate-bridged di-iron proteins. Unlike previous DF proteins, DF3 is highly soluble in water (up to 3 mM) and forms stable complexes with several metal ions (Zn, Co, and Mn), with the desired secondary structure and the expected stoichiometry of two ions per protein. UV–vis studies of Co(II) and Fe(III) complexes confirm a metal-binding environment similar to previous di-Co(II)- and di-Fe(III)-DF proteins, including the presence of a µ-oxo-di-Fe(III) unit. Interestingly, UV–vis, EPR, and resonance Raman studies suggest the interaction of a tyro-sine adjacent to the di-Fe(III) center. The design of DF3 was aimed at increasing the accessibility of small molecules to the active site of the four-helix bundle. Indeed, binding of azide to the di-Fe(III) site demonstrates a more accessible metal site compared with previous DFs. In fact, fitting of the binding curve to the Hill equation allows us to quantify a 150% accessibility enhancement, with respect to DF2. All these results represent a significant step towards the development of a functional synthetic DF metalloprotein. PMID:20225070

Polymeric phase change nanocomposite (PMMA/Fe:ZnO) for electronic packaging application

NASA Astrophysics Data System (ADS)

Maji, Pranabi; Choudhary, Ram Bilash; Majhi, Malati

2018-01-01

This paper reported the effect of Fe-doped ZnO (Fe:ZnO) nanoparticles on the structural, morphological, thermal, optical and dielectric properties of PMMA matrix. Fe-doped ZnO nanoparticle was synthesized by co-precipitation method, after its surface modification incorporated into the PMMA matrix by free radical polymerization method. The phase analysis and crystal structure were investigated by XRD and FTIR technique. These studies confirmed the chemical structure of the PMMA/Fe:ZnO nanocomposite. FESEM image showed the pyramidal shape and high porosity of PMMA/Fe:ZnO nanocomposite. Thermal analysis of the sample was carried out by thermo-gravimetric analyzer. PMMA/Fe:ZnO nanocomposite was found to have better thermal stability compared to pure one. Broadband dielectric spectroscopic technique was used to investigate the transition of electrical properties of Fe-doped ZnO nanoparticle reinforced PMMA matrix in temperature range 313-373 K. The results elucidated a phase transition from glassy to rubbery state at 344 K.

Concretionary manganese-iron oxides in streams and their usefulness as a sample medium for geochemical prospecting

USGS Publications Warehouse

Nowlan, G.A.

1976-01-01

Correlation studies of 400 samples of sieved stream sediments and 325 samples of fluvial, concretionary Mn-Fe oxides from Maine resulted in the separation of elements into the following categories: (1) elements not scavenged by Mn-Fe oxides - B, Cr, K, Mg, Rb, Sc, Ti, V, and Zr; (2) elements probably not scavenged by Mn-Fe oxides - Ag, Be, Ca, Ga, La, Sb, and Y; (3) elements scavenged weakly by Mn-Fe oxides - Cu, Mo, Pb, and Sr; (4) elements scavenged strongly by Mn oxides - Ba, Cd, Co, Ni, Tl, and Zn; and (5) elements scavenged strongly by Fe oxides - As and In. Studies of the scavenged elements showed that the deviation from the mean is characteristically greater in oxide samples as compared to sieved sediments from the same locality. However, a significant increase in contrast between anomalous and background localities, when oxides are the sample medium, more than offsets the disadvantage of data scatter. The use of oxides as a sampling medium clearly and significantly accentuates anomalous localities. In general, non-ratioed data on oxides give very nearly the same results as data consisting of scavenged elements ratioed to Mn and Fe. However, ratioed data expand the geographic area of specific anomalies. Cd and Zn consistently show strong correlations with concretionary Mn-Fe oxides, but their concentrations in the oxides do not generally show as much contrast between anomalous and background localities as do Cu, Mo, and Pb. These latter elements are strongly scavenged where rocks are mineralized. ?? 1976.

Metal concentrations in the soils and native plants surrounding the old flotation tailings pond of the copper mining and smelting complex Bor (Serbia).

PubMed

Antonijević, M M; Dimitrijević, M D; Milić, S M; Nujkić, M M

2012-03-01

In this study concentrations of metals in the native plants and soils surrounding the old flotation tailings pond of the copper mine were determined. It has been established that the soil is heavily contaminated with copper, iron and arsenic, the mean concentrations being 1585.6, 29,462.5 and 171.7 mg kg(-1) respectively. All the plants, except manganese, accumulated metallic elements in concentrations which were either in the range of critical and phytotoxic values (Pb and As) or higher (Zn), and even much higher (Cu and Fe) than these values. Otherwise, the accumulation of Mn, Pb and As was considerably lower than that of Cu, Fe and Zn. In most plants the accumulation of target metals was highest in the root. Several plant species showed high bioaccumulation and translocation factor values, which classify them into species for potential use in phytoextraction. The BCF and TF values determined in Prunus persica were 1.20 and 3.95 for Cu, 1.5 and 6.0 for Zn and 1.96 and 5.44 for Pb. In Saponaria officinalis these values were 2.53 and 1.27 for Zn, and in Juglans regia L. they were 8.76 and 17.75 for Zn. The translocation factor in most plants, for most metals, was higher than one, whereas the highest value was determined in Populus nigra for Zn, amounting to 17.8. Among several tolerant species, the most suitable ones for phytostabilization proved to be Robinia pseudoacacia L. for Zn and Verbascum phlomoides L., Saponaria officinalis and Centaurea jacea L. for Mn, Pb and As. This journal is © The Royal Society of Chemistry 2012

Silicic Acid and Beer Consumption Reverses the Metal Imbalance and the Prooxidant Status Induced by Aluminum Nitrate in Mouse Brain.

PubMed

González-Muñoz, María José; Garcimartán, Alba; Meseguer, Isabel; Mateos-Vega, Carmen José; Orellana, José María; Peña-Fernández, Antonio; Benedí, Juana; Sánchez-Muniz, Francisco J

2017-01-01

Emerging evidence suggests that by affecting mineral balance, aluminum (Al) may enhance some events associated with neurodegenerative diseases. To examine the effect of Al(NO3)3 exposure on brain Al, cooper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), silicon (Si), and zinc (Zn) levels, and the metal-change implication in brain oxidant and inflammatory status. Four groups of six-week-old male NMRI mice were treated for three months: i) controls, administrated with deionized water; ii) Al, which received Al(NO3)3; iii) Al+silicic acid, which were given Al(NO3)3 plus silicic acid; and iv) Al+beer, which received Al(NO3)3 plus beer. Brain Al and TBARS levels and TNFα and GPx expressions increased, while Cu, Mn, and Zn levels, and catalase and CuZn-SOD expression decreased (at least, p < 0.05) in Al versus control animals. Al, Si, and TBARS levels and TNFα expression decreased (p < 0.05) in Al+silicic acid and Al+beer specimens while Cu, Mn, and Zn levels and antioxidant expression increased versus the Al group. Brain Al levels correlated negatively with those of Cu, Fe, Mn, and Zn, and catalase, CuZn-SOD, and GPx enzyme expressions but positively with Si and TBARS levels and TNFα expression. Two components of the principal component analysis (PCA) explained 71.2% of total data variance (p < 0.001). PCA connected the pro-oxidant markers with brain Al content, while brain Zn and Cu levels were closer to antioxidant enzyme expression. Administration of Al(NO3)3 induced metal imbalance, inflammation, and antioxidant status impairment in the brain. Those effects were blocked to a significant extent by silicic acid and beer administration.

"Invisible" gold and PGE elements in synthetic crystals of sphalerite and covellite: A EPMA, LA-ICP-MS and XAFS study

NASA Astrophysics Data System (ADS)

Tonkacheev, Dmitry; Chareev, Dmitry; Abramova, Vera; Tagirov, Boris

2016-04-01

Sphalerite and covellite are widespread minerals in the different genetic types of deposits and forms under the various conditions. The purpose of this work is to determine the possible range of concentration and chemical state of Au and PGE (Pt, Pd, Rh) in sphalerite (Zn,Fe) S and covellite (CuS). These minerals were synthesized using gas transport and salt flux techniques. The crystals of ZnS were grown using the gas transport method at 850°C and the salt flux one using NaCl/KCl, CsCl/NaCl/KCl, and LiCl/RbCl eutectic mixtures at 850, 645 and 470°C, respectively. CuS crystals were synthesized using the salt flux method in RbCl/LiCl melt at 470 and 340°C. The trace metal activity was always controlled by the presence of pure metal or its sulfide, and, therefore, the concentration of these elements in synthesized phases represent the maximum possible value for given T/f(S2) synthesis parameters. The LA-ICP-MS and/or EPMA techniques were used to determine the Au concentration in synthesized phases. The concentration of Au in sphalerite, synthesized at 850°C with admixture of Cd, Se, In, Fe, and Mn, reached 0.3wt%, whereas the sphalerite cell parameter extremely increased up to 5.4161Å relatively to 5.4060 Å for pure ZnS. It was found that the observed high Au concentration is caused by the presence of In (2091±46 ppm Au in sample with Fe and In in comparison with 14±7 for Se-bearing ZnS, 94±12 ppm for Fe-Mn-bearing sphalerite, and 96±46 for Fe-bearing sphalerite. The concentration of Au in Fe-bearing sphalerite synthesized at 645°C does not exceed 5 ppm. Therefore, increase of temperature results in the increase of Au concentration in sphalerite. The concentration of Au in another Fe-bearing-sphalerite series synthesized using gas transport method at 850°C various from 200 to 500 ppm and depends on the iron content. This fact could be related to the oxidation state or Fe in ZnS-FeS solid solution series. The concentration of Pt and Pd, Rh in sphalerite is below the detection limit of LA-ICP-MS (~30 ppb). However, these trace elements change the cathodoluminescence properties of ZnS. The concentration or gold in covellite was determined by both LA-ICP-MS and EPMA techniques and the final values clearly fit together. The maximum concentration can be observed at 450° and equal to 0.3wt%. This value changes minor due to the increasing of the temperature. In principle, adding admixtures of In, Zn, Se, Cu, Sb, Bi did not affect on the concentration of Au. However, in experiment where sulfur is excessive and a mixture of In, Zn, Se, Cu, Sb, Bi, were added the concentration of Au is equal 0.128+0.028 ppm. The gold distribution in covellite and sphalerite is always homogeneous. According to XANES data, atoms of Au in the crystal structure covellite is in triangles, formed by the atoms of Cu. In sphalerite gold is in "invisible" state too.

Structural and magnetic properties of Ni-Zn and Ni-Zn-Co ferrites

NASA Astrophysics Data System (ADS)

Knyazev, A. V.; Zakharchuk, I.; Lähderanta, E.; Baidakov, K. V.; Knyazeva, S. S.; Ladenkov, I. V.

2017-08-01

Ni-Zn and Ni-Zn-Co ferrite powders with nominal compositions Ni0.5Zn0.5Fe2O4 and Ni0.5Zn0.3Co0.2Fe2O4 were prepared by the solid-state reaction synthesis with periodic regrinding during the calcination at 1073 K. The structure of Ni0.5Zn0.5Fe2O4 and Ni0.5Zn0.3Co0.2Fe2O4 was refined assuming space group F d-3m. Scanning electron microscopy revealed the average sizes of the crystalline ferrite particles are 130-630 nm for Ni0.5Zn0.5Fe2O4 and 140-350 nm for Ni0.5Zn0.3Co0.2Fe2O4. The room temperature saturation magnetizations are 59.7 emu/g for Ni0.5Zn0.5Fe2O4 and 57.1 emu/g for Ni0.5Zn0.3Co0.2Fe2O4. The coercivity of the samples is found to be much larger than that of bulk ferrites and increases with Co introduction. The Curie temperature tends to increase upon Zn substitution by Co, as well. The temperature dependences of magnetization measured using zero-field cooled and field cooled protocols exhibit large spin frustration and spin-glass-like behavior.

Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

PubMed

Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

2015-11-21

An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites.

Tri-functional Fe2O3-encased Ag-doped ZnO nanoframework: magnetically retrievable antimicrobial photocatalyst

NASA Astrophysics Data System (ADS)

Karunakaran, Chockalingam; Vinayagamoorthy, Pazhamalai

2016-11-01

Fe2O3-encased ZnO nanoframework was obtained by hydrothermal method and was doped with Ag through photoreduction process. Energy dispersive x-ray spectroscopy, transmission electron microscopy (TEM), high resolution TEM, selected area electron diffractometry, x-ray diffractometry and Raman spectroscopy were employed for the structural characterization of the synthesized material. While the charge transfer resistance of the prepared nanomaterial is larger than those of Fe2O3 and ZnO the coercivity of the nanocomposite is less than that of hydrothermally obtained Fe2O3 nanostructures. Although Fe2O3/Ag-ZnO exhibits weak visible light absorption its band gap energy does not differ from that of ZnO. The photoluminescence of the fabricated nanoframework is similar to that of ZnO. The radiative recombination of charge carriers is slightly slower in Fe2O3/Ag-ZnO than in ZnO. The synthesized Fe2O3-encased Ag-doped ZnO, under UV A light, exhibits sustainable photocatalytic activity to degrade dye and is magnetically recoverable. Also, the Fe2O3/Ag-ZnO nanocomposite disinfects bacteria effectively in absence of direct illumination.

Mineral composition of lamb carcasses from the United States and New Zealand.

PubMed

Lin, K C; Cross, H R; Johnson, H K; Breidenstein, B C; Randecker, V; Field, R A

1988-01-01

The mineral composition-iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), fluoride (F), and phosphorus (P) (New Zealand lamb only)-of lean tissue from lamb retail cuts was studied. Twenty-four US lamb carcasses of different ages (5 to 11 months), geographical regions (Texas, Colorado and Montana) and USDA quality grades (Prime and Choice) and 27 New Zealand lamb carcasses from three weight groups (11 to 12·5 kg, 13 to 14·5 kg, and 16·5 to 18 kg), age rangining from 7 to 8 months, were selected for use in this study. Mineral concentrations were influenced more by retail cut and age than by quality grade or weigth group. Foreshank and shoulder cuts from both the US and New Zealand group consistently had the highest (P < 0·05) Zn content among the cuts. The K content of the muscle in US lambs increased as age increased, while the level of Ca and Zn in New Zealand lambs decreased as carcass weight increased. Except for Ca, the mineral concentrations of the lean tissue from US lambs were higher than the New Zealand lambs, although the differences were not always significant. US lambs had approximately 20%, 30% and 37% more Fe, Zn and Mg, respectively, but 27% less Ca than lean tissue from the New Zealand lambs. Copyright © 1989. Published by Elsevier Ltd.

Thermal Analysis on the Pyrolysis of Tetrabromobisphenol A and Electric Arc Furnace Dust Mixtures

NASA Astrophysics Data System (ADS)

Al-Harahsheh, Mohammad; Al-Otoom, Awni; Al-Jarrah, Muhannad; Altarawneh, Mohammednoor; Kingman, Sam

2018-02-01

The pyrolysis of Tetrabromobisphenol A (TBBPA) mixed with electric arc furnace dust (EAFD) was studied using thermogravimetric analysis (TGA) and theoretically analyzed using thermodynamic equilibrium calculations. Mixtures of both materials with varying TBBPA loads (1:1 and 1:3) were prepared and pyrolyzed in a nitrogen atmosphere under dynamic heating conditions at heating rates of 5 and 10 °C/min. The mixtures degraded through several steps, including decomposition of TBBPA yielding mainly HBr, bromination of metal oxides, followed by their evaporation in the sequence of CuBr3, ZnBr2, PbBr2, FeBr2, MnBr2, KBr, NaBr, CaBr2, and MgBr2, and finally reduction of the remaining metal oxides by the char formed from decomposition of TBBPA. Thermodynamic calculations suggest the possibility of selective bromination of zinc and lead followed by their evaporation, leaving iron in its oxide form, while the char formed may serve as a reduction agent for iron oxides into metallic iron. However, at higher TBBPA volumes, iron bromide forms, which can also be evaporated at a temperature higher than those of ZnBr2 and PbBr2. Results from this work provide practical insight into selective recovery of valuable metals from EAFD while at the same time recycling the hazardous bromine content in TBBPA.

Heavy metal contamination of the soils used for stocking raw materials in the former ILVA iron-steel industrial plant of Bagnoli (southern Italy).

PubMed

Adamo, P; Arienzo, M; Bianco, M R; Terribile, F; Violante, P

2002-08-05

The total contents and the chemical and mineralogical forms of the metals Fe, Al, Cu, Co, Cr, Pb, Zn, Ni and Mn in the horizons of a soil profile, representative of an area devoted to stocking raw materials in the dismantled iron-steel industrial plant of ILVA of Bagnoli (Naples), were studied by physical and chemical methods. The geological setting of the study area is the result of volcanic activity in the Phlegrean Fields, a group of polygenic volcanoes to the west of Naples, which give rise to the parent soil material. Soil morphology appeared to be strongly disturbed by the occurrence and stratification of materials used in the industrial process. Fine sediments illuviation down the profile resulted in the occurrence of silt and clay coatings. The total contents of Cu, Co, Cr, Pb, Zn and Ni, in the whole soil samples, especially in the surface layers, were above the regulatory levels (Cu 120, Co 20, Cr 150, Pb 100, Zn 150, Ni 120 mg kg(-1)) stated by the Italian Ministry of Environment for soils in public, private and residential areas, and below the levels (Cu 600, Co 250, Cr 800, Pb 1000, Zn 1500, Ni 500 mg kg(-1)) outlined for soils and subsoils of industrial and commercial areas (Gazzetta Ufficiale della Repubblica Italiana, 1999). Speciation of heavy metals and the determination of the different chemical pools in the fraction < 2 mm identified the large presence of elements trapped in the mineralogical structure of oxides and silicates and occluded in easily reducible manganese or iron oxides. A constant amount of Cu was associated with organic compounds. A significant amount of Zn (> 20%) was extracted in diluted acetic acid solution, indicating that the element was present in a more readily and potentially available form. In the clay fraction (< 2 microm) heavy metals were associated with both amorphous and crystalline iron forms. The presence of iron-rich clay coatings was evident in the illuvial pores of deeper horizons. Enrichment in Cu, Co, Cr and Zn of the coatings was observed. Possible translocation of metals down through the soil profile mainly bound to fine particles of relatively inert forms of iron is hypothesised. The dispersion in water of the clay fraction resulted in an average percentage dispersion of approximately 20% with a peak of 41.7% at 68-72 cm depth. Magnetite, goethite, hematite, calcite and quartz mixed with K-feldspars, clynopyroxenes and mica occurred in the coarse sand fractions (2-0.2 mm) of the soil samples from all the surface horizons. Talcum and goethite together with clay minerals at 1.4 nm, kaolinite and illite were found in the clays (< 2 microm).

An Animal-Source Food Supplement Increases Micronutrient Intakes and Iron Status among Reproductive-Age Women in Rural Vietnam.

PubMed

Hall, Andrew G; Ngu, Tu; Nga, Hoang T; Quyen, Phi N; Hong Anh, Pham T; King, Janet C

2017-06-01

Background: Few studies have examined the impact of local animal-source foods (ASFs) on the nutritional status of reproductive-age women in developing countries. Objective: We hypothesized that a midmorning snack of local ASF for 6 mo would reduce dietary micronutrient deficiencies [usual intake less than the estimated average requirement (EAR)] and improve blood biomarkers of iron, zinc, and vitamins A and B-12 status among nonpregnant, reproductive-age women in rural Vietnam. Methods: One hundred seventeen women, 18-30 y old, were randomly assigned to receive either an ASF (mean: 144 kcal, 8.9 mg Fe, 2.7 mg Zn, 1050 μg retinoic acid equivalent vitamin A, and 5.5 μg vitamin B-12) or a control snack (mean: 150 kcal, 2.0 mg Fe, 0.9 mg Zn, 0 μg retinoic acid equivalent vitamin A, and 0 μg vitamin B-12) 5 d/wk for 6 mo. Usual nutrient intakes were estimated by repeated 24-h dietary recalls. Blood samples were collected at baseline and 3 and 6 mo. Because of the relation between nutritional status and inflammation, serum C-reactive protein, α-1-acid-glycoprotein, and urinary tract infections (UTIs) were also monitored. Results: Eighty-nine women (47 in the ASF group and 42 controls) completed the study. In the ASF group, intakes of iron and vitamins A and B-12 below the EAR were eliminated, and the prevalence of a low zinc intake was reduced to 9.6% compared with 64.7% in controls ( P < 0.001). At 6 mo, a modest increase ( P < 0.05) in hemoglobin and iron status occurred in the ASF group compared with the control group, but plasma zinc, retinol, and serum vitamin B-12 concentrations did not differ. UTI relative risk was 3.9 ( P < 0.05) among women assigned to the ASF group who had a low whole-body iron status at baseline. Conclusions: Adding a small amount of locally produced ASF to the diets of reproductive-age Vietnamese women improved micronutrient intakes and iron status. However, the increased UTI incidence in women in the ASF group with initially lower iron stores warrants further investigation. © 2017 American Society for Nutrition.

Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

NASA Astrophysics Data System (ADS)

Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

2016-05-01

Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic compounds. In summary, the information obtained by the present approach using a microbial model system provides important information to better understand the interactions between heavy metals and biofilms, and microbially formed Fe(III) minerals and heavy metals in complex natural environments.

Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

USGS Publications Warehouse

Fabisch, Maria; Beulig, Felix; Akob, Denise M.; Küsel, Kirsten

2013-01-01

We identified and quantified abundant iron-oxidizing bacteria (FeOB) at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7), to moderately acidic (R2, pH 4.4), to slightly acidic (R3, pH 6.3) in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U) bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic “Ferrovum myxofaciens” was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and “Ferrovum myxofaciens” revealed that ~72% (R2 sediment) and 37% (R3 sediment) of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

Light-controlled resistive switching characteristics in ZnO/BiFeO3/ZnO thin film

NASA Astrophysics Data System (ADS)

Liang, Dandan; Li, Xiaoping; Wang, Junshuai; Wu, Liangchen; Chen, Peng

2018-07-01

ZnO/BiFeO3/ZnO multilayer was fabricated on silicon (Si) substrate by radio-frequency magnetron sputtering system. The resistive switching characteristics in ZnO/BiFeO3/ZnO devices are observed, and the resistive switching behavior can be modulated by white light.

Contribution of bioavailable iron and zinc to the diet of Honduran children under 24 month

PubMed

Fernández-Palacios, Lorena; Ros-Berruezo, Gaspar; Barrientos-Augustinus, Elsa; Jirón de Caballero, Elizabeth; Frontela-Saseta, Carmen

2017-03-30

Objective: In the present study we analyzed 18 baby food (10 made from traditional Honduran recipes, and 8 industrial baby food sold in that country) involving the staple food of Honduran excluded infants breast milk and infant formulas. Material and methods: The content and bioaccesibility (soluble and dialysable fractions) of Fe and Zn were determined. For thisin vitro gastrointestinal digestion in a first phase of gastric digestion (pepsin) followed by a second phase of intestinal digestion (with pancreatin and bile salts) was simulated. The atomic absorption spectrometry mineral content measured in soluble and dialyzable fractions. Results: Traditional porridges from Honduras (PTH) showed low density of micronutrients being the PTH prepared based on “rice with beans and greens”, “rice with ground beans” and “beans with banana” which had a higher content values of 1.96, 1.56, and 1.46 mg Fe/100 g, respectively, although in vitroavailability values below 50% of its content. For Zn in these recipes, the values found were very low being below the detection limit. In relation to industrial porridges (PIH), those of “rice”, “wheat with milk” and “5 cereals” they had a higher content of Fe (9.4, 8.53 and 7.56 mg Fe/100 g, respectively). Its availability in vitro was greater than 70% in all cases. PIH Zn showed values of 1.36, and 0.99 mg Zn/100 g samples of “wheat with milk” and “wheat with honey”, respectively, and increased availability of 75%. Conclusions: It is shown that PTH have some limitations in its formulation that makes the selected micronutrients are in fewer and even less bioaccessible, compared with PIH, so review is recommended to avoid supplementation of these micronutrients and help improve the nutritional status of the child population as Honduran model country in Central America.

Phase Equilibria in the ZnO-"FeO"-SiO2 System in Reducing Atmosphere and in the ZnO-"FeO"-SiO2-"Cu2O" System in Equilibrium with Liquid Copper Metal at 1250 °C (1523 K)

NASA Astrophysics Data System (ADS)

Hidayat, Taufiq; Hayes, Peter C.; Jak, Evgueni

2018-05-01

Recent experimental studies in the ZnO-"FeO"-SiO2 system in reducing atmosphere demonstrated significant discrepancies with the current FactSage thermodynamic model developed using previous experimental data in this system in equilibrium with metallic iron and air. The present experimental study on phase equilibria in the ZnO-"FeO"-SiO2-"Cu2O" system in equilibrium with liquid copper at 1250 °C (1523 K) at low copper oxide concentrations in slag was initiated and undertaken to resolve these discrepancies. A high-temperature equilibration-rapid quenching-electron-probe X-ray microanalysis (EPMA) technique using a primary phase substrate support and closed system approach with Cu metal introduced to determine effective equilibrium oxygen partial pressure from the Cumetal/Cu2Oslag equilibria was applied to provide accurate information on the liquidus and corresponding solid compositions in the spinel, willemite, and tridymite primary phase fields. The present results confirmed the accuracy of the FactSage model, resolved discrepancies, and demonstrated significant uncertainties in the recent studies by other authors on the system in the open reducing atmosphere. The present study shows how this closed system approach can be used to obtain key thermodynamic data on phase equilibria in systems containing volatile metal species, overcoming the limitations and uncertainties encountered in conventional open gas/condensed phase equilibration with these systems. The study highlights the importance of the focus on obtaining accurate experimental data and the risks of misleading information from inadequate experimental control and analysis. The study also demonstrates that continuing in-depth critical review and analysis of the elemental reactions taking place in complex systems is an essential step in phase equilibrium research.

Amyloid Plaques in PSAPP Mice Bind Less Metal than Plaques in Human Alzheimer's Disease

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

Leskovjan, A.; Lanzirotti, A; Miller, L

2009-01-01

Amyloid beta (A{Beta}) is the primary component of Alzheimer's disease (AD) plaques, a key pathological feature of the disease. Metal ions of zinc (Zn), copper (Cu), iron (Fe), and calcium (Ca) are elevated in human amyloid plaques and are thought to be involved in neurodegeneration. Transgenic mouse models of AD also exhibit amyloid plaques, but fail to exhibit the high degree of neurodegeneration observed in humans. In this study, we imaged the Zn, Cu, Fe, and Ca ion distribution in the PSAPP transgenic mouse model representing end-stage AD (N = 6) using synchrotron X-ray fluorescence (XRF) microprobe. In order tomore » account for differences in density in the plaques, the relative protein content was imaged with synchrotron Fourier transform infrared microspectroscopy (FTIRM) on the same samples. FTIRM results revealed a 61% increase in protein content in the plaques compared to the surrounding tissue. After normalizing to protein density, we found that the PSAPP plaques contained only a 29% increase in Zn and there was actually less Cu, Fe, and Ca in the plaque compared to the surrounding tissue. Since metal binding to A{beta} is thought to induce redox chemistry that is toxic to neurons, the reduced metal binding in PSAPP mice is consistent with the lack of neurodegeneration in these animals. These findings were in stark contrast to the high metal ion content observed in human AD plaques, further implicating the role of metal ions in human AD pathology.« less

Ricinus communis L. (castor bean) as a potential candidate for revegetating industrial waste contaminated sites in peri-urban Greater Hyderabad: remarks on seed oil.

PubMed

Boda, Ravi Kiran; Majeti, Narasimha Vara Prasad; Suthari, Sateesh

2017-08-01

Ricinus communis L. (castor bean or castor oil plant) was found growing on metal-contaminated sites (4) of peri-urban Greater Hyderabad comprises of erstwhile industrial areas viz Bollaram, Patancheru, Bharatnagar, and Kattedan industrial areas. During 2013-2017, about 60 research papers have appeared focusing the role of castor bean in phytoremediation of co-contaminated soils, co-generation of biomaterials, and environmental cleanup, as bioenergy crop and sustainable development. The present study is focused on its use as a multipurpose phytoremediation crop for phytostabilization and revegetation of waste disposed peri-urban contaminated soils. To determine the plant tolerance level, metal accumulation, chlorophyll, protein, proline, lipid peroxidation, oil content, and soil properties were characterized. It was noticed that the castor plant and soils have high concentration of metals such as cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), and zinc (Zn). The soils have high phosphorous (P), adequate nitrogen (N), and low concentration of potassium (K). Iron (Fe) concentrations ranged from1672±50.91 to 2166±155.78 mg kg -1 in the soil. The trend of metal accumulation Fe>Zn>Mn>Pb>Cd was found in different plant parts at polluted sites. The translocation of Cd and Pb showed values more than one in industrial areas viz Bollaram, Kattedan, and Bharatnagar indicating the plants resistance to metal toxicity. Chlorophyll and protein content reduced while proline and malondialdehyde increased due to its tolerance level under metal exposure. The content of ricinoleic acid was higher, and the fatty acids composition of polluted areas was almost similar to that of the control area. Thus, R. communis L. can be employed for reclamation of heavy metal contaminated soils.

Factors influencing intestinal cadmium uptake in pregnant Bangladeshi women-A prospective cohort study

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

Kippler, M.; Goessler, W.; Nermell, B.

Experimental studies indicate that zinc (Zn) and calcium (Ca) status, in addition to iron (Fe) status, affect gastrointestinal absorption of cadmium (Cd), an environmental pollutant that is toxic to kidneys, bone and endocrine systems. The aim of this study was to evaluate how various nutritional factors influence the uptake of Cd in women, particularly during pregnancy. The study was carried out in a rural area of Bangladesh, where malnutrition is prevalent and exposure to Cd via food appears elevated. The uptake of Cd was evaluated by associations between erythrocyte Cd concentrations (Ery-Cd), a marker of ongoing Cd exposure, and concentrationsmore » of nutritional markers. Blood samples, collected in early pregnancy and 6 months postpartum, were analyzed by inductively coupled plasma mass spectrometry (ICPMS). Ery-Cd varied considerably (range: 0.31-5.4 {mu}g/kg) with a median of 1.1 {mu}g/kg (approximately 0.5 {mu}g/L in whole blood) in early pregnancy. Ery-Cd was associated with erythrocyte manganese (Ery-Mn; positively), plasma ferritin (p-Ft; negatively), and erythrocyte Ca (Ery-Ca; negatively) in decreasing order, indicating common transporters for Cd, Fe and Mn. There was no evidence of Cd uptake via Zn transporters, but the association between Ery-Cd and p-Ft seemed to be dependent on adequate Zn status. On average, Ery-Cd increased significantly by 0.2 {mu}g/kg from early pregnancy to 6 months postpartum, apparently due to up-regulated divalent metal transporter 1 (DMT1). In conclusion, intestinal uptake of Cd appears to be influenced either directly or indirectly by several micronutrients, in particular Fe, Mn and Zn. The negative association with Ca may suggest that Cd inhibits the transport of Ca to blood.« less

Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis).

PubMed

Guha, Anirban; Gera, Sandeep; Sharma, Anshu

2012-03-01

Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu), iron (Fe), zinc (Zn), cobalt (Co) and manganese (Mn) and enzyme activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in riverine buffalo milk can be used as an indicator of subclinical mastitis (SCM) with the aim of developing suitable diagnostic kit for SCM. Trace elements and enzyme activity in milk were estimated with Atomic absorption Spectrophotometer, GBC 932 plus and biochemical methods, respectively. Somatic cell count (SCC) was done microscopically. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. A statistically significant (p<0.01) increase in SCC, Fe, Zn, Co and LDH occurred in SCM milk containing gram positive bacterial agents only. ALP was found to be elevated in milk infected by both gram positive and negative bacteria. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and SCC≥2×10(5) cells/ml of milk as the benchmark. Only ALP and Zn, the former being superior, were found to be suitable for diagnosis of SCM irrespective of etiological agents. LDH, Co and Fe can be introduced in the screening programs where Gram positive bacteria are omnipresent. It is recommended that both ALP and Zn be measured together in milk to diagnose buffalo SCM, irrespective of etiology.

In-Situ Crafting of ZnFe₂O₄ Nanoparticles Impregnated within Continuous Carbon Network as Advanced Anode Materials.

PubMed

Jiang, Beibei; Han, Cuiping; Li, Bo; He, Yanjie; Lin, Zhiqun

2016-02-23

The ability to create a synergistic effect of nanostructure engineering and its hybridization with conductive carbonaceous material is highly desirable for attaining high-performance lithium ion batteries (LIBs). Herein, we judiciously crafted ZnFe2O4/carbon nanocomposites composed of ZnFe2O4 nanoparticles with an average size of 16 ± 5 nm encapsulated within the continuous carbon network as anode materials for LIBs. Such intriguing nanocomposites were yielded in situ via the pyrolysis-induced carbonization of polystyrene@poly(acrylic acid) (PS@PAA) core@shell nanospheres in conjunction with the formation of ZnFe2O4 nanoparticles through the thermal decomposition of ZnFe2O4 precursors incorporated within the PS@PAA nanospheres. By systematically varying the ZnFe2O4 content in the ZnFe2O4/carbon nanocomposites, the nanocomposite containing 79.3 wt % ZnFe2O4 was found to exhibit an excellent rate performance with high capacities of 1238, 1198, 1136, 1052, 926, and 521 mAh g(-1) at specific currents of 100, 200, 500, 1000, 2000, and 5000 mA g(-1), respectively. Moreover, cycling performance of the ZnFe2O4/carbon nanocomposite with 79.3 wt % ZnFe2O4 at specific currents of 200 mA g(-1) delivered an outstanding prolonged cycling stability for several hundred cycles.

In situ synthesis of water-soluble magnetic graphitic carbon nitride photocatalyst and its synergistic catalytic performance.

PubMed

Zhang, Shouwei; Li, Jiaxing; Zeng, Meiyi; Zhao, Guixia; Xu, Jinzhang; Hu, Wenping; Wang, Xiangke

2013-12-11

Water-soluble magnetic-functionalized graphitic carbon nitride (g-C3N4) composites were synthesized successfully by in situ decorating spinel ZnFe2O4 nanoparticles on g-C3N4 sheets (CN-ZnFe) through a one-step solvothermal method. The magnetic properties of CN-ZnFe can be effectively controlled via tuning the coverage density and the size of ZnFe2O4 nanoparticles. The results indicate that the CN-ZnFe exhibits excellent photocatalytic efficiency for methyl orange (MO) and fast separation from aqueous solution by magnet. Interestingly, the catalytic performance of the CN-ZnFe is strongly dependent on the loading of ZnFe2O4. The optimum activity of 160CN-ZnFe photocatalyst is almost 6.4 and 5.6 times higher than those of individual g-C3N4 and ZnFe2O4 toward MO degradation, respectively. By carefully investigating the influence factors, a possible mechanism is proposed and it is believed that the synergistic effect of g-C3N4 and ZnFe2O4, the smaller particle size, and the high solubility in water contribute to the effective electron-hole pairs separation and excellent photocatalytic efficiency. This work could provide new insights that g-C3N4 sheets function as good support to develop highly efficient g-C3N4-based magnetic photocatalysts in environmental pollution cleanup.

Facile synthesis of magnetic ZnFe2O4-reduced graphene oxide hybrid and its photo-Fenton-like behavior under visible iradiation.

PubMed

Yao, Yunjin; Qin, Jiacheng; Cai, Yunmu; Wei, Fengyu; Lu, Fang; Wang, Shaobin

2014-06-01

A magnetic ZnFe2O4-reduced graphene oxide (rGO) hybrid was successfully developed as a heterogeneous catalyst for photo-Fenton-like decolorization of various dyes using peroxymonosulfate (PMS) as an oxidant under visible light irradiation. Through an in situ chemical deposition and reduction, ZnFe2O4 nanoparticles (NPs) with an average size of 23.7 nm were anchored uniformly on rGO sheets to form a ZnFe2O4-rGO hybrid. The catalytic activities in oxidative decomposition of organic dyes were evaluated. The reaction kinetics, effect of ion species and strength, catalytic stability, degradation mechanism, as well as the roles of ZnFe2O4 and graphene were also studied. ZnFe2O4-rGO showed to be a promising photocatalyst with magnetism for the oxidative degradation of aqueous organic pollutants and simple separation. The combination of ZnFe2O4 NPs with graphene sheets leads to a much higher catalytic activity than pure ZnFe2O4. Graphene acted as not only a support and stabilizer for ZnFe2O4 to prevent them from aggregation, largely improving the charge separation in the hybrid material, but also a catalyst for activating PMS to produce sulfate radicals at the same time. The ZnFe2O4-rGO hybrid exhibited stable performance without losing activity after five successive runs.

Hydrogen sulfide regulates the levels of key metabolites and antioxidant defense system to counteract oxidative stress in pepper (Capsicum annuum L.) plants exposed to high zinc regime.

PubMed

Kaya, Cengiz; Ashraf, Muhammad; Akram, Nudrat Aisha

2018-05-01

In the present experiment, we aimed to test the impact of hydrogen sulfide (H 2 S) on growth, key oxidant such as hydrogen peroxide, mineral elements, and antioxidative defense in Capia-type red sweet pepper (Capsicum annuum L.) plants subjected to high concentration of zinc (Zn). A factorial experiment was designed with two Zn levels (0.05 and 0.5 mM) and 0.2 mM sodium hydrosulfide (NaHS) as a donor of H 2 S supplied in combination plus nutrient solution through the root zone. High level of Zn led to reduce dry mass, chlorophyll pigments, fruit yield, leaf maximum fluorescence, and relative water content, but enhanced endogenous hydrogen peroxide (H 2 O 2 ), free proline, malondialdehyde (MDA), electrolyte leakage (EL), H 2 S, as well as the activities of peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) enzymes. Exogenously applied NaHS significantly enhanced plant growth, fruit yield, water status, the levels of H 2 S and proline as well as the activities of different antioxidant enzymes, while it significantly suppressed EL, MDA, and H 2 O 2 contents in the pepper plants receiving low level Zn. NaHS application to the control plants did not significantly change all these parameters tested except the dry matter which increased significantly. High Zn regime led to increase intrinsic Zn levels in the leaves and roots, but it lowered leaf nitrogen (N), phosphorus (P), and iron (Fe) concentrations. However, NaHS reduces the Zn conc. and enhances Fe and N in leaf and root organs. It can be concluded that NaHS can mitigate the harmful effects of Zn on plant growth particularly by lowering the concentrations of H 2 O 2 , Zn, EL, and MDA, and enhancing the activities of enzymatic antioxidants and levels of essential nutrients in pepper plants.

Magnetic properties of alluvial soils polluted with heavy metals

NASA Astrophysics Data System (ADS)

Dlouha, S.; Petrovsky, E.; Boruvka, L.; Kapicka, A.; Grison, H.

2012-04-01

Magnetic properties of soils, reflecting mineralogy, concentration and grain-size distribution of Fe-oxides, proved to be useful tool in assessing the soil properties in terms of various environmental conditions. Measurement of soil magnetic properties presents a convenient method to investigate the natural environmental changes in soils as well as the anthropogenic pollution of soils with several risk elements. The effect of fluvial pollution with Cd, Cu, Pb and Zn on magnetic soil properties was studied on highly contaminated alluvial soils from the mining/smelting district (Příbram; CZ) using a combination of magnetic and geochemical methods. The basic soil characteristics, the content of heavy metals, oxalate, and dithionite extractable iron were determined in selected soil samples. Soil profiles were sampled using HUMAX soil corer and the magnetic susceptibility was measured in situ, further detailed magnetic analyses of selected distinct layers were carried out. Two types of variations of magnetic properties in soil profiles were observed corresponding to indentified soil types (Fluvisols, and Gleyic Fluvisols). Significantly higher values of topsoil magnetic susceptibility compared to underlying soil are accompanied with high concentration of heavy metals. Sequential extraction analysis proved the binding of Pb, Zn and Cd in Fe and Mn oxides. Concentration and size-dependent parameters (anhysteretic and isothermal magnetization) were measured on bulk samples in terms of assessing the origin of magnetic components. The results enabled to distinguish clearly topsoil layers enhanced with heavy metals from subsoil samples. The dominance of particles with pseudo-single domain behavior in topsoil and paramagnetic/antiferromagnetic contribution in subsoil were observed. These measurements were verified with room temperature hysteresis measurement carried out on bulk samples and magnetic extracts. Thermomagnetic analysis of magnetic susceptibility measured on magnetic extracts indicated the presence of magnetite/maghemite in the uppermost layers, and strong mineralogical transformation of iron oxyhydroxides during heating. Magnetic techniques give valuable information about the soil Fe oxides, which are useful for investigation of the environmental effects in soil. Key words: magnetic methods, Fe oxides, pollution, alluvial soils.

Structural classification of RAO3( MO) n compounds ( R =Sc, In, Y, or lanthanides; A =Fe(III), Ga, Cr, or Al; M =divalent cation; n = 1-11)

NASA Astrophysics Data System (ADS)

Kimizuka, Noboru; Mohri, Takahiko

1989-01-01

A series of new compounds RAO3( MO) n ( n = 1-11) having spinel, YbFe 2O 4, or InFeO 3(ZnO) n types of structures were newly synthesized ( R =Sc, In, Y, Lu, Yb, Tm, or Er; A =Fe(III), Ga, Cr, or Al; M =Mg, Mn, Fe(II), Co, Ni, Zn, or Cd) at elevated temperatures. The conditions of synthesis and the lattice constants for these compounds are reported. The stacking sequences of the InO 1.5, (FeZn)O 2.5, and ZnO layers for InFeO 3(ZnO) 10 and the TmO 1.5, (AlZn)O 2.5, and ZnO layers for TmAlO 3(ZnO) 11 are presented, respectively. The crystal structures of the( RAO3) m( MO) n phases ( R =Sc, In, Y, or lanthanide elements; A =Fe(III), Ga, Cr, or Al; M =divalent cation elements; m and n =integer) are classified into four crystal structure types (K 2NiF 4, CaFe 2O 4, YbFe 2O 4, and spinel), based upon the constituent cations R, A, and M

Zn-Fe-CNTs catalytic in situ generation of H2O2 for Fenton-like degradation of sulfamethoxazole.

PubMed

Liu, Yong; Fan, Qin; Wang, Jianlong

2018-01-15

A novel Fenton-like catalyst (Zn-Fe-CNTs) capable of converting O 2 to H 2 O 2 and further to OH was prepared through infiltration fusion method followed by chemical replacement in argon atmosphere. The catalyst was characterized by SEM, EDS, TEM, XRD and XPS. The reaction between Zn-Fe-CNTs and O 2 in aqueous solution could generate H 2 O 2 in situ, which was further transferred to OH. The Fenton-like degradation of sulfamethoxazole (SMX) using Zn-Fe-CNTs as catalyst was evaluated. The results indicated that Zn-Fe-CNTs had a coral porous structure with a BET area of 51.67m 2 /g, exhibiting excellent adsorption capacity for SMX, which enhanced its degradation. The particles of Zn 0 and Fe 0 /Fe 2 O 3 were observed on the surface of Zn-Fe-CNTs. The mixture of Zn 0 and CNTs could reduce O 2 into H 2 O 2 by micro-electrolysis and Fe 0 /Fe 2 O 3 could catalyze in-situ generation of H 2 O 2 to produce OH through Fenton-like process. When initial pH=1.5, T=25°C, O 2 flow rate=400mL/min, Zn-Fe-CNTs=0.6g/L, SMX=25mg/L and reaction time=10min, the removal efficiency of SMX and TOC was 100% and 51.3%, respectively. The intermediates were detected and the possible pathway of SMX degradation and the mechanism of Zn-Fe-CNTs/O 2 process were tentatively proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Third generation biosensing matrix based on Fe-implanted ZnO thin film

NASA Astrophysics Data System (ADS)

Saha, Shibu; Gupta, Vinay; Sreenivas, K.; Tan, H. H.; Jagadish, C.

2010-09-01

Third generation biosensor based on Fe-implanted ZnO (Fe-ZnO) thin film has been demonstrated. Implantation of Fe in rf-sputtered ZnO thin film introduces redox center along with shallow donor level and thereby enhance its electron transfer property. Glucose oxidase (GOx), chosen as model enzyme, has been immobilized on the surface of the matrix. Cyclic voltammetry and photometric assay show that the prepared bioelectrode, GOx/Fe-ZnO/ITO/Glass is sensitive to the glucose concentration with enhanced response of 0.326 μA mM-1 cm-2 and low Km of 2.76 mM. The results show promising application of Fe-implanted ZnO thin film as an attractive matrix for third generation biosensing.

Redox-induced mobilization of copper, selenium, and zinc in deltaic soils originating from Mississippi (U.S.A.) and Nile (Egypt) River Deltas: A better understanding of biogeochemical processes for safe environmental management.

PubMed

Shaheen, Sabry M; Frohne, Tina; White, John R; DeLaune, Ron D; Rinklebe, Jörg

2017-01-15

Studies about the mobilization of potentially toxic elements (PTEs) in deltaic soils can be challenging, provide critical information on assessing the potential risk and fate of these elements and for sustainable management of these soils. The impact of redox potential (E H ), pH, iron (Fe), manganese (Mn), sulfate (SO 4 2- ), chloride (Cl - ), aliphatic dissolved organic carbon (DOC), and aromatic dissolved organic carbon (DAC) on the mobilization of copper (Cu), selenium (Se), and zinc (Zn) was studied in two soils collected from the Nile and Mississippi Rivers deltaic plains focused on increasing our understanding of the fate of these toxic elements. Soils were exposed to a range of redox conditions stepwise from reducing to oxidizing soil conditions using an automated biogeochemical microcosm apparatus. Concentrations of DOC and Fe were high under reducing conditions as compared to oxidizing conditions in both soils. The proportion of DAC in relation to DOC in solution (aromaticity) was high in the Nile Delta soil (NDS) and low in the Mississippi Delta soil (MDS) under oxidizing conditions. Mobilization of Cu was low under reducing conditions in both soils which was likely caused by sulfide precipitation and as a result of reduction of Cu 2+ to Cu 1+ . Mobilization of Se was high under low E H in both soils. Release of Se was positively correlated with DOC, Fe, Mn, and SO 4 2- in the NDS, and with Fe in the MDS. Mobilization of Zn showed negative correlations with E H and pH in the NDS while these correlations were non-significant in the MDS. The release dynamics of dissolved Zn could be governed mainly by the chemistry of Fe and Mn in the NDS and by the chemistry of Mn in the MDS. Our findings suggest that a release of Se and Zn occurs under anaerobic conditions, while aerobic conditions favor the release of Cu in both soils. In conclusion, the release of Cu, Se, and Zn under different reducing and oxidizing conditions in deltaic wetland soils should be taken into account due to increased mobilization and the potential environmental risks associated with food security in utilizing these soils for flooded agricultural and fisheries systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-Performance Epoxy-Resin-Bonded Magnets Produced from the Sm2Fe17Nx Powders Coated by Copper and Zinc Metals

NASA Astrophysics Data System (ADS)

Noguchi, Kenji; Machida, Ken-ichi; Adachi, Gin-ya

2001-04-01

Fine powders of Sm2Fe17Nx coated with copper metal reduced from CuCl2 and/or zinc metal subsequently derived by photo-decomposition of diethylzinc [Zn(C2H5)2] were prepared, and their magnetic properties were characterized in addition to those of epoxy-resin-bonded magnets produced from the coated powders (Cu/Sm2Fe17Nx, Zn/Sm2Fe17Nx and Zn/Cu/Sm2Fe17Nx). The remanence (Br) and maximum energy product [(\\mathit{BH})max] of double metal-coated Zn/Cu/Sm2Fe17Nx powders were maintained at higher levels than those of single Zn metal-coated Sm2Fe17Nx ones (Zn/Sm2Fe17Nx) even after heat treatment at 673 K since the oxidation resistance and thermal stability were effectively improved by formation of the thick and uniform protection layer on the surface of Sm2Fe17Nx particles. Moreover, the epoxy-resin-bonded magnets produced from the Zn/Cu/Sm2Fe17Nx powders possessed good corrosion resistance in air at 393 K which it resulted in the smaller thermal irreversible flux loss than that of uncoated and single Zn metal-coated Sm2Fe17Nx powders in the temperature range of above 393 K.

Effects of inorganic nanoparticles on viability and catabolic activities of Agrobacterium sp. PH-08 during biodegradation of dibenzofuran.

PubMed

Le, Thao Thanh; Murugesan, Kumarasamy; Kim, Eun-Ju; Chang, Yoon-Seok

2014-09-01

This study investigated the cytotoxicity, genotoxicity, and growth inhibition effects of four different inorganic nanoparticles (NPs) such as aluminum (nAl), iron (nFe), nickel (nNi), and zinc (nZn) on a dibenzofuran (DF) degrading bacterium Agrobacterium sp. PH-08. NP (0-1,000 mg L(-1)) -treated bacterial cells were assessed for cytotoxicity, genotoxicity, growth and biodegradation activities at biochemical and molecular levels. In an aqueous system, the bacterial cells treated with nAl, nZn and nNi at 500 mg L(-1) showed significant reduction in cell viability (30-93.6 %, p < 0.05), while nFe had no significant inhibition on bacterial cell viability. In the presence of nAl, nZn and nNi, the cells exhibited elevated levels of reactive oxygen species (ROS), DNA damage and cell death. Furthermore, NP exposure showed significant (p < 0.05) impairment in DF and catechol biodegradation activities. The reduction in DF biodegradation was ranged about 71.7-91.6 % with single NPs treatments while reached up to 96.3 % with a mixture of NPs. Molecular and biochemical investigations also clearly revealed that NP exposure drastically affected the catechol-2,3-dioxygenase activities and its gene (c23o) expression. However, no significant inhibition was observed in nFe treatment. The bacterial extracellular polymeric materials and by-products from DF degradation can be assumed as key factors in diminishing the toxic effects of NPs, especially for nFe. This study clearly demonstrates the impact of single and mixed NPs on the microbial catabolism of xenobiotic-degrading bacteria at biochemical and molecular levels. This is the first study on estimating the impact of mixed NPs on microbial biodegradation.

Bhasmas: unique ayurvedic metallic-herbal preparations, chemical characterization.

PubMed

Kumar, A; Nair, A G C; Reddy, A V R; Garg, A N

2006-03-01

Bhasmas are unique Ayurvedic metallic preparations with herbal juices/fruits, known in the Indian subcontinent since the seventh century BC and widely recommended for treatment of a variety of chronic ailments. Twenty bhasmas based on calcium, iron, zinc, mercury, silver, potassium, arsenic, copper, tin, and gemstones were analyzed for up to 18 elements by instrumental neutron activation analysis, including their C, H, N, and S contents. In addition to the major constituent element found at % level, several other essential elements such as Na, K, Ca, Mg, V, Mn, Fe, Cu, and Zn have also been found in microg/g amounts and ultratrace (ng/g) amounts of Au and Co. These seem to remain chelated with organic ligands derived from medicinal herbs. The bhasmas are biologically produced nanoparticles and are taken along with milk, butter, honey, or ghee (a preparation from milk); thus, this makes these elements easily assimilable, eliminating their harmful effects and enhancing their biocompatibility. Siddha Makaradhwaja, a mercury preparation is found to be stoichiometrically HgS without any traces of any other element. Similarly, Swet Parpati is stoichiometrically KNO3 but is found to have Mn, Cu, Zn, Na, P, and Cl as well. An attempt has been made to correlate the metallic contents with their medicinal importance. Na and K, the two electrolytic elements, seem to be well correlated, although K/Na varies in a wide range from 0.06 to 95, with specifically low values for Ca-, Fe-, and Zn-based bhasmas. K/P also varies in a wide range from 0.23 to 12, although for most bhasmas (n = 12), it is 2.3 +/- 1.2. Further, Fe/Mn is linearly correlated (r = 0.96) with Fe in nine noniron bhasmas.

Second-Sphere Effects in Dinuclear FeIIIZnII Hydrolase Biomimetics: Tuning Binding and Reactivity Properties.

PubMed

Camargo, Tiago Pacheco; Neves, Ademir; Peralta, Rosely A; Chaves, Cláudia; Maia, Elene C P; Lizarazo-Jaimes, Edgar H; Gomes, Dawidson A; Bortolotto, Tiago; Norberto, Douglas R; Terenzi, Hernán; Tierney, David L; Schenk, Gerhard

2018-01-02

Herein, we report the synthesis and characterization of two dinuclear Fe III Zn II complexes [Fe III Zn II LP1] (1) and [Fe III Zn II LP2] (2), in which LP1 and LP2 are conjugated systems containing one and two pyrene groups, respectively, connected via the diamine -HN(CH 2 ) 4 NH- spacer to the well-known N 5 O 2 -donor H 2 L ligand (H 2 L = 2-bis{[(2-pyridylmethyl)aminomethyl]-6-[(2-hydroxybenzyl)(2-pyridylmethyl)]aminomethyl}-4-methylphenol). The complex [Fe III Zn II L1] (3), in which H 2 L was modified to H 2 L1, with a carbonyl group attached to the terminal phenol group, was included in this study for comparison purposes. 1 Both complexes 1 and 2 were satisfactorily characterized in the solid state and in solution. Extended X-ray absorption fine structure data for 1 and 3 in an acetonitrile solution show that the multiply bridged structure seen in the solid state of 3 is retained in solution. Potentiometric and UV-vis titration of 1 and 2 show that electrostatic interaction between the protonated amino groups and coordinated water molecules significantly decreases the pK a of the iron(III)-bound water compared to those of 3. On the other hand, catalytic activity studies using 1 and 2 in the hydrolysis of the activated substrate bis(2,4-dinitrophenyl)phosphate (BDNPP) resulted in a significant increase in the association of the substrate (K ass ≅ 1/K M ) compared to that of 3 because of electrostatic and hydrophobic interactions between BDNPP and the side-chain diaminopyrene of the ligands H 2 LP1 and H 2 LP2. In addition, the introduction of the pyrene motifs in 1 and 2 enhanced their activity toward DNA and as effective antitumor drugs, although the biochemical mechanism of the latter effect is currently under investigation. These complexes represent interesting examples of how to promote an increase in the activity of traditional artificial metal nucleases by introducing second-coordination-sphere effects.

[Effect of atmospheric CO2 concentration and nitrogen application level on absorption and transportation of nutrient elements in oilseed rape].

PubMed

Wang, Wen-ming; Zhang, Zhen-hua; Song, Hai-xing; Liu, Qiang; Rong, Xiang-min; Guan, Chun-yun; Zeng, Jing; Yuan, Dan

2015-07-01

Effect of elevated atmospheric-CO2 (780 µmol . mol-1) on the absorption and transportation of secondary nutrient elements (calcium, magnesium, sulphur) and micronutrient elements (iron, manganese, zinc, molybdenum and boron) in oilseed rape at the stem elongation stage were studied by greenhouse simulated method. Compared with the ambient CO2 condition, the content of Zn in stem was increased and the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with no nitrogen (N) application; the contents of Ca, S, B and Zn were increased, and the contents of Mg, Mn, Mo and Fe were decreased under the elevated atmospheric CO2 with N application (0.2 g N . kg-1 soil); except the content of Mo in leaf was increased, the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with two levels of N application. Compared with the ambient CO2 condition, the amounts of Ca and S relative to the total amount of secondary nutrient elements in stem and the amounts of B and Zn relative to the total amount of micronutrient elements in stem were increased under the elevated-CO2 treatment with both levels of N application, and the corresponding values of Mg, Fe, Mn and Mo were decreased; no-N application treatment increased the proportion of Ca distributed into the leaves, and the proportion of Mg distributed into leaves was increased by the normal-N application level; the proportions of Mn, Zn and Mo distributed into the leaves were increased at both N application levels. Without N application, the elevation of atmospheric CO2 increased the transport coefficients of SFe, Mo and SS,B, but decreased the transport coefficients of SMg,Fe, SMg, Mn and SS,Fe, indicating the proportions of Mo, S transported into the upper part of plant tissues was higher than that of Fe, and the corresponding value of B was higher than that observed for S, the corresponding value of Mg was higher than that of Fe and Mn. Under normal-N application, the elevation of atmospheric CO2 increased the transport coefficients of SMg,Fe, SMg,Mn and SS,B, but decreased the transport coefficients of SCa, Mg, SFe,Mo and SS,Fe indicating the proportions of Fe, Mn and Ca transported into the upper part of plant tissues was higher than that of Mg; the corresponding value of B was higher than that observed for S, the corresponding value of Fe was higher than that of Mo, and the corresponding value of S was higher than that of Fe.

UV Light-Driven Photodegradation of Methylene Blue by Using Mn0.5Zn0.5Fe2O4/SiO2 Nanocomposites

NASA Astrophysics Data System (ADS)

Indrayana, I. P. T.; Julian, T.; Suharyadi, E.

2018-04-01

The photodegradation activity of nanocomposites for 20 ppm methylene blue solution has been investigated in this work. Nanocomposites Mn0.5Zn0.5Fe2O4/SiO2 have been synthesized using coprecipitation method. The X-ray diffraction (XRD) pattern confirmed the formation of three phases in sample Mn0.5Zn0.5Fe2O4/SiO2 i.e., Mn0.5Zn0.5Fe2O4, Zn(OH)2, and SiO2. The appearance of SiO2 phase showed that the encapsulation process has been carried out. The calculated particles size of Mn0.5Zn0.5Fe2O4/SiO2 is greater than Mn0.5Zn0.5Fe2O4. Bonding analysis via vibrational spectra for Mn0.5Zn0.5Fe2O4/SiO2 confirmed the formation of bonds Me-O-Si stretching (2854.65 cm-1) and Si-O-Si asymmetric stretching (1026.13 cm-1). The optical gap energy of Mn0.5Zn0.5Fe2O4/SiO2 was smaller (2.70 eV) than Mn0.5Zn0.5Fe2O4 (3.04 eV) due to smaller lattice dislocation and microstrain that affect their electronic structure. The Mn0.5Zn0.5Fe2O4/SiO2 showed high photodegradation ability due to smaller optical gap energy and the appearance of SiO2 ligand that can easily attract dye molecules. The Mn0.5Zn0.5Fe2O4/SiO2 also showed high degradation activity even without UV light radiation. The result showed that photodegradation reaction doesn’t follow pseudo-first order kinetics.

Effects of ferrous carbamoyl glycine on iron state and absorption in an iron-deficient rat model.

PubMed

Zhang, Yuzhe; Sun, Xiaoming; Xie, Chunyan; Shu, Xugang; Oso, Abimbola Oladele; Ruan, Zheng; Deng, Ze-Yuan; Wu, Xin; Yin, Yulong

2015-11-01

An iron-deficient rat model was established and used to determine the effects of different iron sources on iron metabolism and absorption. Iron-deficient rats were assigned to one of three treatment groups, and their diet was supplemented with deionized water (control), Fe-CGly, or FeSO4 for 8 days via intragastric administration. Blood samples were obtained for analysis of iron-related properties, and the small intestine and liver were removed for quantitative reverse transcription PCR of genes related to iron metabolism. The serum total iron-binding capacity (TIBC) levels of rats in Fe-CGly and FeSO4 supplementation groups was lower (P < 0.05) than that of the rats in the control group. The rats in Fe-CGly group exhibited higher (P < 0.05) plasma Fe and ferritin levels and lower (P < 0.05) TIBC levels compared with the rats in FeSO4 groups. The relative expression of liver hepcidin increased (P < 0.05) by tenfold and 80-fold in the Fe-CGly and FeSO4 groups, respectively, whereas divalent metal transporter 1, duodenal cytochrome b, and ferroportin 1 expression decreased (P < 0.05) in the duodenum in both Fe-CGly and FeSO4 group. A comparison between Fe-CGly and FeSO4 group showed that iron regulatory protein 1 (IRP1) and iron regulatory protein (IRP2) expressions were reduced (P < 0.05) in rats administered FeSO4 than in rats administered with Fe-Cgly. These results indicate that Fe-CGly rapidly improves the blood iron status and that IRP1 and IRP2 may play an important role in the intestinal absorption of Fe-CGly.

Studies on different iron source absorption by in situ ligated intestinal loops of broilers.

PubMed

Jia, Y F; Jiang, M M; Sun, J; Shi, R B; Liu, D S

2015-02-01

The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

Dopant concentration dependent growth of Fe:ZnO nanostructures

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

Sahai, Anshuman; Goswami, Navendu, E-mail: navendugoswami@gmail.com

2016-05-23

Systematic investigations of structural properties of 1-10% Fe doped ZnO nanostructure (Fe:ZnO NS) prepared via chemical precipitation method have been reported. Structural properties were probed thoroughly employing scanning electron microscope (SEM) and transmission electron microscope (TEM), energy dispersive X-ray (EDAX) analysis and X-ray diffraction (XRD). Morphological transformation of nanostructures (NS) with Fe incorporation is evident in SEM/TEM images. Nanoparticles (NP) obtained with 1% Fe, evolve to nanorods (NR) for 3% Fe; NR transform to nanocones (NC) (for 5% and 7% Fe) and finally NC transform to nanoflakes (NF) at 10% Fe. Morover, primary phase of Zn{sub 1-x}Fe{sub x}O along withmore » secondary phases of ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3} were also revealed through XRD measurements. Based on collective XRD, SEM, TEM, and EDAX interpretations, a model for morphological evolution of NS was proposed and the pivotal role of Fe dopant was deciphered.« less

Tissue distribution of metals in white-fronted geese and spot-billed ducks from Korea.

PubMed

Kim, Jungsoo; Oh, Jong-Min

2013-07-01

This study presents concentrations of Fe, Zn, Mn, Cu, Pb and Cd in livers, kidneys, muscles and bones of white-fronted geese Anser albifrons (geese) and spot-billed ducks Anas poecilorhyncha (ducks). Iron in livers, kidneys and muscles, Zn in muscles, Mn and Cd in every tissue, Cu in livers, muscles and bones and Pb in bones differed between species, and there were significant differences among tissues in both species. Essential elements such as Fe, Zn, Mn and Cu concentrations were within the background levels. Lead concentrations in livers of 7 of 14 geese and 7 of 19 ducks and in bones of 4 of 19 ducks exceeded background concentrations for waterfowl (5 μg/g dw for the liver, 10 μg/g dw for the bone). Almost all samples of both species had the background Cd concentrations in the liver (33 of 33 geese and ducks) and kidney (14 geese and 18 ducks). Tissue concentrations of Cd were greater in geese than ducks. In contrast, tissue concentrations of Pb in bones were greater in ducks than in geese. These different trends for Cd and Pb reflect a short and/or long term difference in exposure and degree of accumulation of these metals.

Trace elements and antioxidant enzymes in Behçet's disease.

PubMed

Saglam, K; Serce, A F; Yilmaz, M I; Bulucu, F; Aydin, A; Akay, C; Sayal, A

2002-07-01

Free oxygen radicals and insufficiency of antioxidant enzymes have been implicated in the pathogenesis of Behçet's disease (BD). Trace elements function as cofactors to antioxidant enzymes. The antioxidant system and trace elements were investigated in many different studies, including BD, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in BD to contribute to the knowledge of pathogenesis and treatment of this disease. We examined glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities together with selenium (Se), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) levels in plasma and erythrocytes of 50 patients with BD and 30 healthy controls. It was found that in patients with BD, erythrocyte GSH-Px and SOD activities and erythrocyte Se, plasma Fe, Mn, and Zn levels were significantly lower than those of controls and that plasma Cu, erythrocyte Zn, and Mn levels were significantly higher in patients with BD. Insufficient antioxidant enzyme activities were observed in patients with BD. The mechanism(s) of this phenomenon is not clear. Therefore, supplementation with trace elements involved in the antioxidative processes may increase scavenger enzyme activities, and consequently, an improvement in clinical symptoms may be expected.

Phytoremediation of domestic wastewaters in free water surface constructed wetlands using Azolla pinnata.

PubMed

Akinbile, Christopher O; Ogunrinde, Temitope A; Che Bt Man, Hasfalina; Aziz, Hamidi Abdul

2016-01-01

Two constructed wetlands, one with Azolla pinnata plant (CW1) and the other without (CW2) for treating domestic wastewaters were developed. Fifteen water parameters which include: Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Total Phosphorus (TP), Total Nitrogen (TN), Ammoniacal Nitrogen (NH3N), Turbidity, pH, Electrical Conductivity (EC), Iron (Fe), Magnesium (Mg), Manganese (Mn), and heavy metals such as Lead (Pb) and Zinc (Zn) were analyzed using standard laboratory procedures. The experiments were conducted in two (dry and wet) seasons simultaneously. Results showed considerable reductions in all parameters and metals including Zn in CW1 compared with CW2 in the two seasons considered while Pb and Mn were not detected throughout the study. Zn concentration levels reduced significantly in both seasons just as removal efficiencies of 70.03% and 64.51% were recorded for CW1 while 35.17% and 33.45% were recorded for CW2 in both seasons. There were no significant differences in the removal efficiencies of Fe in both seasons as 99.55%, 59.09%, 88.89%, and 53.56% were recorded in CW1 and CW2 respectively. Azolla pinnata has proved effective in domestic wastewater phytoremediation studies.

Elemental and isotopic behaviour of Zn in Deccan basalt weathering profiles: Chemical weathering from bedrock to laterite and links to Zn deficiency in tropical soils.

PubMed

Suhr, Nils; Schoenberg, Ronny; Chew, David; Rosca, Carolina; Widdowson, Mike; Kamber, Balz S

2018-04-01

Zinc (Zn) is a micronutrient for organisms and essential for plant growth, therefore knowledge of its elemental cycling in the surface environment is important regarding wider aspects of human nutrition and health. To explore the nature of Zn cycling, we compared its weathering behaviour in a sub-recent regolith versus an ancient laterite profile of the Deccan Traps, India - an area of known soil Zn deficiency. We demonstrate that progressive breakdown of primary minerals and the associated formation of phyllosilicates and iron oxides leads to a depletion in Zn, ultimately resulting in a loss of 80% in lateritic residues. This residue is mainly composed of resistant iron oxides and hydroxides ultimately delivering insufficient amounts of bio-available Zn. Moreover, (sub)-tropical weathering in regions experiencing extended tectonic quiescence (e.g., cratons) further enhance the development of old and deep soil profiles that become deficient in Zn. This situation is clearly revealed by the spatial correlation of the global distribution of laterites, cratons (Africa, India, South America and Australia) and known regions of Zn deficient soils that result in health problems for humans whose diet is derived from such land. We also investigate whether this elemental depletion of Zn is accompanied by isotope fractionation. In the saprolitic horizons of both weathering profiles, compositions of δ 66 Zn JMC-Lyon lie within the "crustal average" of +0.27±0.07‰ δ 66 Zn JMC-Lyon . By contrast, soil horizons enriched in secondary oxides show lighter isotope compositions. The isotopic signature of Zn (Δ 66 Zn sample-protolith up to ~ -0.65‰) during the formation of the ferruginous-lateritic weathering profile likely resulted from a combination of biotically- and kinetically-controlled sorption reactions on Fe-oxyhydroxides. Our findings suggest that oxide rich soil types/horizons in (sub)-tropical regions likely exert a control on riverine Zn isotope compositions such that these become heavier than the crustal average. This isotopic behaviour invites a broader study of global soils to test whether light isotope composition alone could serve as an indicator for reduced bioavailability of Zn. Copyright © 2017 Elsevier B.V. All rights reserved.

Anemia induced by high zinc intake in chicks: Mechanisms

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

Pimentel, J.L.; Greger, J.L.; Cook, M.E.

1991-03-15

The mechanisms by which excess Zn induced anemia in chickens was assessed in 8 studies in which chicks were randomly assigned to a 2 {times} 2 factorial arrangement of treatments with 60 or 2,000 {mu}g Zn and 10 or 250 {mu}g Cu/g diet. Less Fe-59 appeared in the plasma 1 hour after a labeled meal when chicks were fed excess Zn in 1 of 2 studies but less Fe-59 appeared in livers of chicks fed excess Zn in both studies. The decrease of Fe-59 uptake into tissues paralleled a decrease in Fe concentrations in livers and tibiotarsi. These differences inmore » tissue Fe did not reflect differences in Fe excretion because excretion and incorporation into tissues of injected Fe-59 was not affected by high Zn intake. Although excess Zn decreased tissue Cu concentrations, excess Zn, per se, did not affect cytosolic superoxide dismutase activity, the in vivo t 1/2 of erythrocytes, or erythrocyte hemolysis in vitro. The decrease in body weight of chicks fed excess Zn indicated that protein synthesis and/or degradation could be affected. Increased incorporation of C-14 tyrosine into liver and bone marrow of chicks fed excess Zn suggested increased protoporphyrin synthesis or metallothionein synthesis. These results indicated that decreased Fe absorption was the primary mechanism by which excess Zn induced anemia.« less

Observed and modeled seasonal trends in dissolved and particulate Cu, Fe, Mn, and Zn in a mining-impacted stream.

PubMed

Butler, Barbara A; Ranville, James F; Ross, Philippe E

2008-06-01

North Fork Clear Creek (NFCC) in Colorado, an acid-mine drainage (AMD) impacted stream, was chosen to examine the distribution of dissolved and particulate Cu, Fe, Mn, and Zn in the water column, with respect to seasonal hydrologic controls. NFCC is a high-gradient stream with discharge directly related to snowmelt and strong seasonal storms. Additionally, conditions in the stream cause rapid precipitation of large amounts of hydrous iron oxides (HFO) that sequester metals. Because AMD-impacted systems are complex, geochemical modeling may assist with predictions and/or confirmations of processes occurring in these environments. This research used Visual-MINTEQ to determine if field data collected over a two and one-half year study would be well represented by modeling with a currently existing model, while limiting the number of processes modeled and without modifications to the existing model's parameters. Observed distributions between dissolved and particulate phases in the water column varied greatly among the metals, with average dissolved fractions being >90% for Mn, approximately 75% for Zn, approximately 30% for Cu, and <10% for Fe. A strong seasonal trend was observed for the metals predominantly in the dissolved phase (Mn and Zn), with increasing concentrations during base-flow conditions and decreasing concentrations during spring-runoff. This trend was less obvious for Cu and Fe. Within hydrologic seasons, storm events significantly influenced in-stream metals concentrations. The most simplified modeling, using solely sorption to HFO, gave predicted percentage particulate Cu results for most samples to within a factor of two of the measured values, but modeling data were biased toward over-prediction. About one-half of the percentage particulate Zn data comparisons fell within a factor of two, with the remaining data being under-predicted. Slightly more complex modeling, which included dissolved organic carbon (DOC) as a solution phase ligand, significantly reduced the positive bias between observed and predicted percentage particulate Cu, while inclusion of hydrous manganese oxide (HMO) yielded model results more representative of the observed percentage particulate Zn. These results indicate that there is validity in the use of an existing model, without alteration and with typically collected water chemistry data, to describe complex natural systems, but that processes considered optimal for one metal might not be applicable for all metals in a given water sample.

Effects of a Tripeptide Iron on Iron-Deficiency Anemia in Rats.

PubMed

Xiao, Chen; Lei, Xingen; Wang, Qingyu; Du, Zhongyao; Jiang, Lu; Chen, Silu; Zhang, Mingjie; Zhang, Hao; Ren, Fazheng

2016-02-01

This study aims to investigate the effects of a tripeptide iron (REE-Fe) on iron-deficiency anemia rats. Sprague-Dawley rats were randomly divided into seven groups: a normal control group, an iron-deficiency control group, and iron-deficiency groups treated with ferrous sulfate (FeSO4), ferrous glycinate (Fe-Gly), or REE-Fe at low-, medium-, or high-dose groups. The rats in the iron-deficiency groups were fed on an iron-deficient diet to establish iron-deficiency anemia (IDA) model. After the model established, different iron supplements were given to the rats once a day by intragastric administration for 21 days. The results showed that REE-Fe had effective restorative action returning body weight, organ coefficients, and hematological parameters in IDA rats to normal level. In addition, comparing with FeSO4 or Fe-Gly, high-dose REE-Fe was more effective on improving the levels of renal coefficient, total iron-binding capacity, and transferrin. Furthermore, the liver hepcidin messenger RNA (mRNA) expression in the high-dose group was significantly higher (p < 0.05) than that in the FeSO4 or Fe-Gly group and showed no significant difference (p > 0.05) with the normal control group. The findings suggest that REE-Fe is an effective source of iron supplement for IDA rats and might be exploited as a new iron fortifier.

Fe{sub 3}O{sub 4}/CuO/ZnO/Nano graphene platelets (Fe{sub 3}O{sub 4}/CuO/ZnO/NGP) composites prepared by sol-gel method with enhanced sonocatalytic activity for the removal of dye

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

Hendry, Tju; Taufik, Ardiansyah; Saleh, Rosari, E-mail: rosari.saleh@gmail.com, E-mail: rosari.saleh@ui.ac.id

2016-04-19

In this study, an attempt has been made to synthesize nanographene platelets coupled with Fe3O4/CuO/ZnO (Fe3O4/CuO/ZnO/NGP) with various ZnO loadings using a two step methods, sol-gel followed by hydrothermal method. Characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer. The sonocatalytic performance was evaluated by degradation of methylene blue under ultrasonic irradiation.The Fe3O4/CuO/ZnO/NGP showed superior sonocatalytic activity than the Fe3O4/CuO/ZnO materials. They also showed high stability and can be easily separated from the reaction system for recycling process.

2D Nanoporous Fe-N/C Nanosheets as Highly Efficient Non-Platinum Electrocatalysts for Oxygen Reduction Reaction in Zn-Air Battery.

PubMed

Yang, Zheng Kun; Lin, Ling; Xu, An-Wu

2016-11-01

It is an ongoing challenge to fabricate nonprecious oxygen reduction reaction (ORR) catalysts that can be comparable to or exceed the efficiency of platinum. A highly active non-platinum self-supporting Fe-N/C catalyst has been developed through the pyrolysis of a new type of precursor of iron coordination complex, in which 1,4-bis(1H-1,3,7,8-tetraazacyclopenta(1)phenanthren-2-yl)benzene (btcpb) functions as a ligand complexing Fe(II) ions. The optimal catalyst pyrolyzed at 700 °C (Fe-N/C-700) shows the best ORR activity with a half-wave potential (E 1/2 ) of 840 mV versus reversible hydrogen electrode (RHE) in 0.1 m KOH, which is more positive than that of commercial Pt/C (E 1/2 : 835 mV vs RHE). Additionally, the Fe-N/C-700 catalyst also exhibits high ORR activity in 0.1 m HClO 4 with the onset potential and E 1/2 comparable to those of the Pt/C catalyst. Notably, the Fe-N/C-700 catalyst displays superior durability (9.8 mV loss in 0.1 m KOH and 23.6 mV loss in 0.1 m HClO 4 for E 1/2 after 8000 cycles) and better tolerance to methanol than Pt/C. Furthermore, the Fe-N/C-700 catalyst can be used for fabricating the air electrode in Zn-air battery with a specific capacity of 727 mA hg -1 at 5 mA cm -2 and a negligible voltage loss after continuous operation for 110 h. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ferrate(VI) oxidation of zinc-cyanide complex.

PubMed

Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

2007-10-01

Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate.

Chemical study of the metal-rich globular cluster NGC 5927

NASA Astrophysics Data System (ADS)

Mura-Guzmán, A.; Villanova, S.; Muñoz, C.; Tang, B.

2018-03-01

Globular clusters (GCs) are natural laboratories where stellar and chemical evolution can be studied in detail. In addition, their chemical patterns and kinematics can tell us to which Galactic structure (disc, bulge, halo or extragalactic) the cluster belongs to. NGC 5927 is one of most metal-rich GCs in the Galaxy and its kinematics links it to the thick disc. We present abundance analysis based on high-resolution spectra of seven giant stars. The data were obtained using Fibre Large Array Multi Element Spectrograph/Ultraviolet Echelle Spectrograph (UVES) spectrograph mounted on UT2 telescope of the European Southern Observatory. The principal objective of this work is to perform a wide and detailed chemical abundance analysis of the cluster and look for possible Multiple Populations (MPs). We determined stellar parameters and measured 22 elements corresponding to light (Na, Al), alpha (O, Mg, Si, Ca, Ti), iron-peak (Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), and heavy elements (Y, Zr, Ba, Ce, Nd, Eu). We found a mean iron content of [Fe/H] = -0.47 ± 0.02 (error on the mean). We confirm the existence of MPs in this GC with an O-Na anti-correlation, and moderate spread in Al abundances. We estimate a mean [α/Fe] = 0.25 ± 0.08. Iron-peak elements show no significant spread. The [Ba/Eu] ratios indicate a predominant contribution from SNeII for the formation of the cluster.

Iron Isotopes in Meteorites

NASA Astrophysics Data System (ADS)

Kehm, K.; Alexander, C. M.; Hauri, E. H.

2001-12-01

The recent identification of naturally occurring isotopic mass fractionation of the transition met-als on the Earth has prompted a search for similar variability in meteorites. Studies of Cu, Zn, and Fe, for example, have revealed per-mil level and larger mass fractionations between different bulk meteorites. Such variations can result from temperature-sensitive isotope exchange reactions and kinetic processes, and therefore may reflect conditions in the solar nebula and on meteorite parent bodies. Recent advances in ICP-MS have permitted isotope studies of transition metals and other elements with similarly small isotopic mass dispersions. Among the transition metals, Fe is perhaps the most difficult to analyze by ICP-MS because plasma sources are copious producers of argide molecules that interfere with the measurement of iron isotopes. However, the stable isotope behavior of Fe is of special interest because it is a non-refractory major element in meteorites, present in a variety of mineral associations and redox states. Considerable effort has gone into overcoming the inherent analytical difficulties of measuring Fe using ICP-MS. We recently reported on a technique that achieves argide reduction by operating the plasma source in so-called 'cold' mode. In this presentation, we report results from this ongoing work. To date, analyses of nine different meteorites, and eight individual Tieschitz (H3) chondrules have been completed, along with a number of measurements of the Hawaiian basalt sample Kil1919. All of the bulk meteorite compositions, which include both chondrites and irons, have identical 56Fe/54Fe to within ~ 0.14 per mil (2 sigma), and are indistinguishable from the composition of the terrestrial basalt. The Tieschitz chondrules, on the other hand, tend to have isotopically light compositions. This could reflect formation from fractionated starting material. Alternatively, Fe condensation, under non-equilibrium conditions can enrich light isotopes. Future work will focus on determining the extent of Fe mass fractionation in chondrules from Tieschitz as well as other chondrites. This growing database will help us to understand the conditions in which chondrules formed, potentially placing stringent constraints on theories of their formation.

Layered Double Hydroxides: Potential Release-on-Demand Fertilizers for Plant Zinc Nutrition.

PubMed

López-Rayo, Sandra; Imran, Ahmad; Bruun Hansen, Hans Chr; Schjoerring, Jan K; Magid, Jakob

2017-10-11

A novel zinc (Zn) fertilizer concept based on Zn-doped layered double hydroxides (Zn-doped Mg-Fe-LDHs) has been investigated. Zn-doped Mg-Fe-LDHs were synthesized, their chemical composition was analyzed, and their nutrient release was studied in buffered solutions with different pH values. Uptake of Zn by barley (Hordeum vulgare cv. Antonia) was evaluated in short- (8 weeks), medium- (11 weeks), and long-term (28 weeks) experiments in quartz sand and in a calcareous soil enriched with Zn-doped Mg-Fe-LDHs. The Zn release rate of the Zn-doped Mg-Fe-LDHs was described by a first-order kinetics equation showing maximum release at pH 5.2, reaching approximately 45% of the total Zn content. The Zn concentrations in the plants receiving the LDHs were between 2- and 9.5-fold higher than those in plants without Zn addition. A positive effect of the LDHs was also found in soil. This work documents the long-term Zn release capacity of LDHs complying with a release-on-demand behavior and serves as proof-of-concept that Zn-doped Mg-Fe-LDHs can be used as Zn fertilizers.

Determination of some enzymes and macro- and microelements in stallion seminal plasma and their correlations to semen quality.

PubMed

Pesch, Sandra; Bergmann, Martin; Bostedt, Hartwig

2006-07-15

Seminal plasma is very important for sperm metabolism as well as sperm function and survival and transport in the female genital tract. Analysis of enzyme activities and concentrations of elements can estimate integrity and function of sperm cell membranes. In man much data are available about biochemical analyses of seminal plasma. However, not many studies have been conducted in horses yet. We collected ejaculates from 72 stallions, measured the volume, obtained seminal plasma by centrifugation and examined spermatozoa with light microscopy for motility, concentration, for dead sperm and morphology. Of seminal plasma fluid, we measured activities of aspartate-amino-transferase (AST), gamma-glutamyl-transferase (GGT), alkaline phosphatase (AlP), acid phosphatase (AcP) and lactate-dehydrogenase (LDH) as well as concentrations of sodium (Na(+)), potassium (K(+)), total and ionised calcium (Ca(TOTAL)/Ca(2+)), magnesium (Mg(2+)), phosphate (P), chloride (Cl), copper (Cu), iron (Fe) and zinc (Zn). In addition, correlations among different parameters in light microscopy and seminal plasma were statistically examined by using the Spearman rank correlation coefficient. Median enzyme activities for AST, GGT, AlP, AcP and LDH were 80.0, 7,500, 30,200, 20.0, 81.0 IU/L, respectively. Concentrations of Na(+), K(+), Ca(TOTAL), Ca(2+), Mg(2+), P, Cl were 110.5, 22.1, 2.9, 1.7, 3.1, 1.1 and 114.5 mmol/L, and of microelements Cu, Fe and Zn were 17.8, 1.9 and 13.2 micromol/L, respectively. Furthermore, we found significant correlations between semen volume as well as sperm concentration and AST, GGT, AlP, AcP and LDH as well as Fe and Zn. This made us propose a primary testicular and epididymal origin of these parameters. Significant correlation between GGT and motility may be a sign for its function for cell protection against free radicals. LDH activity significantly correlates with motility and progressive motility, live:dead-ratio and pathomorphology. In our study, LDH seems to be the most predictive enzyme for semen quality. This is the first report about GGT, AcP and LDH activities as well as iron in equine seminal plasma.

Iron bioavailability in 8-24-month-old Thai children from a micronutrient-fortified quick-cooking rice containing ferric ammonium citrate or a mixture of ferrous sulphate and ferric sodium ethylenediaminetetraacetic acid.

PubMed

Chavasit, Visith; Porasuphatana, Suparat; Suthutvoravut, Umaporn; Zeder, Christroph; Hurrell, Richard

2015-12-01

A quick-cooking rice, produced from broken rice, is a convenient ingredient for complementary foods in Thailand. The rice is fortified with micronutrients including iron during the processing procedure, which can cause unacceptable sensory changes. A quick-cooking rice fortified with ferric ammonium citrate (FAC) or a mixture of ferrous sulphate (FeSO4 ) and ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA), with a 2:1 molar ratio of iron from FeSO4  : iron from NaFeEDTA (FeSO4  + NaFeEDTA), gave a product that was organoleptically acceptable. The study compared iron absorption by infants and young children fed with micronutrient-fortified quick-cooking rice containing the test iron compounds or FeSO4 . Micronutrient-fortified quick-cooking rice prepared as a traditional Thai dessert was fed to two groups of 15 8-24-month healthy Thai children. The iron fortificants were isotopically labelled with (57) Fe for the reference FeSO4 or (58) Fe for the tested fortificants, and iron absorption was quantified based on erythrocyte incorporation of the iron isotopes 14 days after feeding. The relative bioavailability of FAC and of the FeSO4  + NaFeEDTA was obtained by comparing their iron absorption with that of FeSO4 . Mean fractional iron absorption was 5.8% [±standard error (SE) 1.9] from FAC and 10.3% (±SE 1.9) from FeSO4  + NaFeEDTA. The relative bioavailability of FAC was 83% (P = 0.02). The relative bioavailability of FeSO4  + NaFeEDTA was 145% (P = 0.001). Iron absorption from the rice containing FAC or FeSO4  + NaFeEDTA was sufficiently high to be used in its formulation, although iron absorption from FeSO4  + NaFeEDTA was significantly higher (P < 0.00001). © 2015 John Wiley & Sons Ltd.

beta-Citryl-L-glutamate is an endogenous iron chelator that occurs naturally in the developing brain.

PubMed

Hamada-Kanazawa, Michiko; Kouda, Makiko; Odani, Akira; Matsuyama, Kaori; Kanazawa, Kiyoka; Hasegawa, Tatsuya; Narahara, Masanori; Miyake, Masaharu

2010-01-01

The compound beta-citryl-L-glutamate (beta-CG) was initially isolated from developing brains, while it has also been found in high concentrations in testes and eyes. However, its functional roles are unclear. To evaluate its coordination with metal ions, we performed pH titration experiments. The stability constant, logbeta(pqr) for M(p)(beta-CG)(q)H(r) was calculated from pH titration data, which showed that beta-CG forms relatively strong complexes with Fe(III), Cu(II), Fe(II) and Zn(II). beta-CG was also found able to solubilize Fe more effectively from Fe(OH)(2) than from Fe(OH)(3). Therefore, we examined the effects of beta-CG on Fe-dependent reactive oxygen species (ROS)-generating systems, as well as the potential ROS-scavenging activities of beta-CG and metal ion-(beta-CG) complexes. beta-CG inhibited the Fe-dependent degradation of deoxyribose and Fe-dependent damage to DNA or plasmid DNA in a dose-dependent manner, whereas it had no effect on Cu-mediated DNA damage. In addition, thermodynamic data showed that beta-CG in a physiological pH solution is an Fe(II) chelator rather than an Fe(III) chelator. Taken together, these findings suggest that beta-CG is an endogenous low molecular weight Fe chelator.

Effect of Tamarindus indica leaf powder on plasma concentrations of copper, zinc, and iron in fluorotic cows.

PubMed

Samal, Pinaki; Patra, R C; Gupta, A R; Mishra, S K; Jena, D; Satapathy, D

2016-10-01

The main objective of the study was to determine the deleterious effect of fluoride on plasma trace minerals of fluorotic cattle and to evaluate the effect of Tamarindus indica leaf powder toward correction of the same. A total of 30 cattle exhibiting chronic sign of fluorosis and 10 healthy cattle from nonfluorotic area were incorporated in this study. Fluorotic cattle were divided into three equal groups consisting of 10 cattle each. Group I from fluoride free area served as healthy control. The Group II received no treatment and served as disease control. Groups III and IV were supplemented with tamarind leaf powder at 15 g and 30 g/day with feed for 60 days. Plasma mineral status was evaluated after 60 days of treatment with double beam atomic absorption spectrophotometer. Statistical analysis of data revealed a significant (p<0.05) decrease in mean plasma copper (Cu) (0.344±0.007 ppm), zinc (Zn) (0.692±0.06 ppm), and iron (Fe) concentration (1.100±0.01 ppm) in fluorotic cattle in comparison to healthy cattle (0.58±0.010, 2.342±0.04, 1.406±0.04 ppm, respectively). Significant (p<0.05) increase in Cu, Zn, and Fe was recorded after supplementation of tamarind leaf powder to the fluorotic cattle. It was concluded that fluorotic cattle might be supplemented with T. indica leaf powder with feed for the correction of the decreased level of certain plasma minerals.

Recalibration of the sphalerite cosmobarometer: Experimental and theoretical treatment

NASA Astrophysics Data System (ADS)

Balabin, Alexey I.; Urusov, Vadim S.

1995-04-01

Temperature dependence of the composition of sphalerite in equilibrium with troilite + metallic iron has been determined experimentally from 400 to 840°C at 1 bar. The high-temperature runs (660-840°C) were conducted in evacuated silica tubes; a new version of the recrystallization in anhydrous halide flux technique was used for attaining equilibrium at 600-400°C. The zero-pressure solvus of sphalerite proved to be at higher FeS contents than was located by Barton and Toulmin (1966). Detailed calculations, based on updated thermochemical appraisal of the sphalerite (Zn,Fe)S solution, have shown the new solvus to be in apparent consistency with the high-pressure experimental data of Hutchison and Scott (1983 ). An improved calibration of the cosmobarometer is presented, based on our experimental results and those of Hutchison and Scott (1983) ; the calibration takes into account some inferences regarding thermodynamic properties of sphalerite solution and low-temperature polymorphism in FeS. Recently published metallographic cooling rates of iron meteorites (Saikumar and Goldstein, 1988) provide estimates of blocking temperatures for Fe diffusion in sphalerite, which fall in the range 205-217°C. Pressures of formation of these meteorites calculated from available sphalerite compositions range from 0 for Landes to 1.8 kbar for Toluca. The most reliable of the pressure estimates exhibit a linear relationship with wt% Ni of the meteorite.

Photoelectrochemical and theoretical investigations of spinel type ferrites (MxFe3-xO4) for water splitting: a mini-review

NASA Astrophysics Data System (ADS)

Taffa, Dereje H.; Dillert, Ralf; Ulpe, Anna C.; Bauerfeind, Katharina C. L.; Bredow, Thomas; Bahnemann, Detlef W.; Wark, Michael

2017-01-01

Solar-assisted water splitting using photoelectrochemical cells (PECs) is one of the promising pathways for the production of hydrogen for renewable energy storage. The nature of the semiconductor material is the primary factor that controls the overall energy conversion efficiency. Finding semiconductor materials with appropriate semiconducting properties (stability, efficient charge separation and transport, abundant, visible light absorption) is still a challenge for developing materials for solar water splitting. Owing to the suitable bandgap for visible light harvesting and the abundance of iron-based oxide semiconductors, they are promising candidates for PECs and have received much research attention. Spinel ferrites are subclasses of iron oxides derived from the classical magnetite (FeIIFe2IIIO4) in which the FeII is replaced by one (some cases two) additional divalent metals. They are generally denoted as MxFe3-xO4 (M=Ca, Mg, Zn, Co, Ni, Mn, and so on) and mostly crystallize in spinel or inverse spinel structures. In this mini review, we present the current state of research in spinel ferrites as photoelectrode materials for PECs application. Strategies to improve energy conversion efficiency (nanostructuring, surface modification, and heterostructuring) will be presented. Furthermore, theoretical findings related to the electronic structure, bandgap, and magnetic properties will be presented and compared with experimental results.

Quality of Graphite Target for Biological/Biomedical/Environmental Applications of 14C-Accelerator Mass Spectrometry

PubMed Central

2010-01-01

Catalytic graphitization for 14C-accelerator mass spectrometry (14C-AMS) produced various forms of elemental carbon. Our high-throughput Zn reduction method (C/Fe = 1:5, 500 °C, 3 h) produced the AMS target of graphite-coated iron powder (GCIP), a mix of nongraphitic carbon and Fe3C. Crystallinity of the AMS targets of GCIP (nongraphitic carbon) was increased to turbostratic carbon by raising the C/Fe ratio from 1:5 to 1:1 and the graphitization temperature from 500 to 585 °C. The AMS target of GCIP containing turbostratic carbon had a large isotopic fractionation and a low AMS ion current. The AMS target of GCIP containing turbostratic carbon also yielded less accurate/precise 14C-AMS measurements because of the lower graphitization yield and lower thermal conductivity that were caused by the higher C/Fe ratio of 1:1. On the other hand, the AMS target of GCIP containing nongraphitic carbon had higher graphitization yield and better thermal conductivity over the AMS target of GCIP containing turbostratic carbon due to optimal surface area provided by the iron powder. Finally, graphitization yield and thermal conductivity were stronger determinants (over graphite crystallinity) for accurate/precise/high-throughput biological, biomedical, and environmental14C-AMS applications such as absorption, distribution, metabolism, elimination (ADME), and physiologically based pharmacokinetics (PBPK) of nutrients, drugs, phytochemicals, and environmental chemicals. PMID:20163100

Nitrogenase-mimic iron-containing chalcogels for photochemical reduction of dinitrogen to ammonia.

PubMed

Liu, Jian; Kelley, Matthew S; Wu, Weiqiang; Banerjee, Abhishek; Douvalis, Alexios P; Wu, Jinsong; Zhang, Yongbo; Schatz, George C; Kanatzidis, Mercouri G

2016-05-17

A nitrogenase-inspired biomimetic chalcogel system comprising double-cubane [Mo2Fe6S8(SPh)3] and single-cubane (Fe4S4) biomimetic clusters demonstrates photocatalytic N2 fixation and conversion to NH3 in ambient temperature and pressure conditions. Replacing the Fe4S4 clusters in this system with other inert ions such as Sb(3+), Sn(4+), Zn(2+) also gave chalcogels that were photocatalytically active. Finally, molybdenum-free chalcogels containing only Fe4S4 clusters are also capable of accomplishing the N2 fixation reaction with even higher efficiency than their Mo2Fe6S8(SPh)3-containing counterparts. Our results suggest that redox-active iron-sulfide-containing materials can activate the N2 molecule upon visible light excitation, which can be reduced all of the way to NH3 using protons and sacrificial electrons in aqueous solution. Evidently, whereas the Mo2Fe6S8(SPh)3 is capable of N2 fixation, Mo itself is not necessary to carry out this process. The initial binding of N2 with chalcogels under illumination was observed with in situ diffuse-reflectance Fourier transform infrared spectroscopy (DRIFTS). (15)N2 isotope experiments confirm that the generated NH3 derives from N2 Density functional theory (DFT) electronic structure calculations suggest that the N2 binding is thermodynamically favorable only with the highly reduced active clusters. The results reported herein contribute to ongoing efforts of mimicking nitrogenase in fixing nitrogen and point to a promising path in developing catalysts for the reduction of N2 under ambient conditions.

Transformation impacts of dissolved and solid phase Fe(II) on trichloroethylene (TCE) reduction in an iron-reducing bacteria (IRB) mixed column system: a mathematical model.

PubMed

Bae, Yeunook; Kim, Dooil; Cho, Hyun-Hee; Singhal, Naresh; Park, Jae-Woo

2012-12-01

In this research, we conducted trichloroethylene (TCE) reduction in a column filled with iron and iron-reducing bacteria (IRB) and developed a mathematical model to investigate the critical reactions between active species in iron/IRB/contaminant systems. The formation of ferrous iron (Fe(II)) in this system with IRB and zero-valent iron (ZVI, Fe(0)) coated with a ferric iron (Fe(III)) crust significantly affected TCE reduction and IRB respiration in various ways. This study presents a new framework for transformation property and reducing ability of both dissolved (Fe(II)(dissolved)) and solid form ferrous iron (Fe(II)(solid)). Results showed that TCE reduction was strongly depressed by Fe(II)(solid) rather than by other inhibitors (e.g., Fe(III) and lactate), suggesting that Fe(II)(solid) might reduce IRB activation due to attachment to IRB cells. Newly exposed Fe(0) from the released Fe(II)(dissolved) was a strong contributor to TCE reduction compared to Fe(II)(solid). In addition, our research confirmed that less Fe(II)(solid) production strongly supported long-term TCE reduction because it may create an easier TCE approach to Fe(0) or increase IRB growth. Our findings will aid the understanding of the contributions of iron media (e.g., Fe(II)(solid), Fe(II)(dissolved), Fe(III), and Fe(0)) to IRB for decontamination in natural groundwater systems. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fractionation study in bioleached metallurgy wastes using six-step sequential extraction.

PubMed

Krasnodebska-Ostrega, Beata; Pałdyna, Joanna; Kowalska, Joanna; Jedynak, Łukasz; Golimowski, Jerzy

2009-08-15

The stored metallurgy wastes contain residues from ore processing operations that are characterized by relatively high concentrations of heavy metals. The bioleaching process makes use of bacteria to recover elements from industrial wastes and to decrease potential risk of environmental contamination. Wastes were treated by solutions containing bacteria. In this work, the optimized six-stage sequential extraction procedure was applied for the fractionation of Ni, Cr, Fe, Mn, Cu and Zn in iron-nickel metallurgy wastes deposited in Southern Poland (Szklary). Fractionation and total concentrations of elements in wastes before and after various bioleaching treatments were studied. Analyses of the extracts were performed by ICP-MS and FAAS. To achieve the most effective bioleaching of Zn, Cr, Ni, Cu, Mn, Fe the usage of both autotrophic and heterotrophic bacteria in sequence, combined with flushing of the residue after bioleaching is required. 80-100% of total metal concentrations were mobilized after the proposed treatment. Wastes treated according to this procedure could be deposited without any risk of environmental contamination and additionally the metals could be recovered for industrial purposes.

Seasonal determination of trace and ultra-trace content in Macrocystis pyrifera from San Jorge Gulf (Patagonia) by Total Reflection X-ray Fluorescence

NASA Astrophysics Data System (ADS)

Salomone, Vanesa N.; Riera, Marina; Cerchietti, Luciana; Custo, Graciela; Muniain, Claudia

2017-05-01

Seaweed have a great capacity to accumulate heavy metals in their tissues. The chemical characterization of seaweed is important due to their use in environmental monitoring and human or animal food. The aim of the present study was to evaluate the multi-elemental composition of seaweed from San Jorge Gulf (Patagonia, Argentina) by Total Reflection X-ray Fluorescence (TXRF). The elements As, Br, Cu, Cr, Fe, Mn, Ni, Pb, Rb, Sr, V and Zn were seasonally analyzed and quantified in blades of Macrocystis pyrifera. TXRF showed to be a suitable technique for simultaneous multi-element analysis in this kind of samples. The results revealed seasonal variations in the chemical content for some elements; arsenic content was maximum in summer and autumn, iron concentration increased to the winter and zinc concentration was maximum in autumn. The sum of principal micronutrients (Fe + Zn + Mn + Cu) varied between 114 and 171 mg k- 1 g dw. The total As concentration ranged between 36 and 66 mg kg- 1. Lead, nickel and copper were not detected.

Preparation of a nanosized as(2)o(3)/mn(0.5)zn(0.5)fe(2)o(4) complex and its anti-tumor effect on hepatocellular carcinoma cells.

PubMed

Zhang, Jia; Zhang, Dongsheng

2009-01-01

Manganese-zinc-ferrite nanoparticles (Mn(0.5)Zn(0.5)Fe(2)O(4), MZF-NPs) prepared by an improved co-precipitation method and were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). Then thermodynamic testing of various doses of MZF-NPs was performed in vitro. The cytotoxicity of the Mn(0.5)Zn(0.5)Fe(2)O(4) nanoparticles in vitro was tested by the MTT assay. A nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex was made by an impregnation process. The complex's shape, component, envelop rate and release rate of As(2)O(3) were measured by SEM, EDS and atom fluorescence spectrometry, respectively. The therapeutic effect of nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex combined with magnetic fluid hyperthermia (MFH) on human hepatocelluar cells were evaluated in vitro by an MTT assay and flow cytometry. The results indicated that Mn(0.5)Zn(0.5)Fe(2)O(4) and nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex were both prepared successfully. The Mn(0.5)Zn(0.5)Fe(2)O(4) nanoparticles had powerful absorption capabilities in a high-frequency alternating electromagnetic field, and had strong magnetic responsiveness. Moreover, Mn(0.5)Zn(0.5)Fe(2)O(4) didn't show cytotoxicity in vitro. The therapeutic result reveals that the nanosized As(2)O(3)/Mn(0.5)Zn(0.5)Fe(2)O(4) complex can significantly inhibit the growth of hepatoma carcinoma cells.

Land Use Land Cover Changes in Detection of Water Quality: A Study Based on Remote Sensing and Multivariate Statistics.

PubMed

Hua, Ang Kean

2017-01-01

Malacca River water quality is affected due to rapid urbanization development. The present study applied LULC changes towards water quality detection in Malacca River. The method uses LULC, PCA, CCA, HCA, NHCA, and ANOVA. PCA confirmed DS, EC, salinity, turbidity, TSS, DO, BOD, COD, As, Hg, Zn, Fe, E. coli , and total coliform. CCA confirmed 14 variables into two variates; first variate involves residential and industrial activities; and second variate involves agriculture, sewage treatment plant, and animal husbandry. HCA and NHCA emphasize that cluster 1 occurs in urban area with Hg, Fe, total coliform, and DO pollution; cluster 3 occurs in suburban area with salinity, EC, and DS; and cluster 2 occurs in rural area with salinity and EC. ANOVA between LULC and water quality data indicates that built-up area significantly polluted the water quality through E. coli , total coliform, EC, BOD, COD, TSS, Hg, Zn, and Fe, while agriculture activities cause EC, TSS, salinity, E. coli , total coliform, arsenic, and iron pollution; and open space causes contamination of turbidity, salinity, EC, and TSS. Research finding provided useful information in identifying pollution sources and understanding LULC with river water quality as references to policy maker for proper management of Land Use area.

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

Oliver, S. A.; Harris, V. G.; Hamdeh, H. H.

The cation site occupancy of a mechanically activated nanocrystalline zinc ferrite powder was determined as (Zn{sub 0.55}{sup 2+}Fe{sub 0.18}{sup 3+}){sub tet}[Zr{sub 0.45}{sup 2+}Fe{sub 1.82}{sup 3+}]{sub oct}O{sub 4} through analysis of extended x-ray absorption fine structure measurements, showing a large redistribution of cations between sites compared to normal zinc ferrite samples. The overpopulation of cations in the octahedral sites was attributed to the ascendance in importance of the ionic radii over the crystal energy and bonding coordination in determining which interstitial sites are occupied in this structurally disordered powder. Slight changes are observed in the local atomic environment about the zincmore » cations, but not the iron cations, with respect to the spinel structure. The presence of Fe{sup 3+} on both sites is consistent with the measured room temperature magnetic properties. (c) 2000 American Institute of Physics.« less

Role of hydrous iron oxide formation in attenuation and diel cycling of dissolved trace metals in a stream affected by acid rock drainage

USGS Publications Warehouse

Parker, S.R.; Gammons, C.H.; Jones, Clain A.; Nimick, D.A.

2007-01-01

Mining-impacted streams have been shown to undergo diel (24-h) fluctuations in concentrations of major and trace elements. Fisher Creek in south-central Montana, USA receives acid rock drainage (ARD) from natural and mining-related sources. A previous diel field study found substantial changes in dissolved metal concentrations at three sites with differing pH regimes during a 24-h period in August 2002. The current work discusses follow-up field sampling of Fisher Creek as well as field and laboratory experiments that examine in greater detail the underlying processes involved in the observed diel concentration changes. The field experiments employed in-stream chambers that were either transparent or opaque to light, filled with stream water and sediment (cobbles coated with hydrous Fe and Al oxides), and placed in the stream to maintain the same temperature. Three sets of laboratory experiments were performed: (1) equilibration of a Cu(II) and Zn(II) containing solution with Fisher Creek stream sediment at pH 6.9 and different temperatures; (2) titration of Fisher Creek water from pH 3.1 to 7 under four different isothermal conditions; and (3) analysis of the effects of temperature on the interaction of an Fe(II) containing solution with Fisher Creek stream sediment under non-oxidizing conditions. Results of these studies are consistent with a model in which Cu, Fe(II), and to a lesser extent Zn, are adsorbed or co-precipitated with hydrous Fe and Al oxides as the pH of Fisher Creek increases from 5.3 to 7.0. The extent of metal attenuation is strongly temperature-dependent, being more pronounced in warm vs. cold water. Furthermore, the sorption/co-precipitation process is shown to be irreversible; once the Cu, Zn, and Fe(II) are removed from solution in warm water, a decrease in temperature does not release the metals back to the water column. ?? 2006 Springer Science+Business Media B.V.

Disinfection of Multidrug Resistant Escherichia coli by Solar-Photocatalysis using Fe-doped ZnO Nanoparticles.

PubMed

Das, Sourav; Sinha, Sayantan; Das, Bhaskar; Jayabalan, R; Suar, Mrutyunjay; Mishra, Amrita; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia; Tripathy, Suraj K

2017-03-07

Spread of antibiotic resistant bacteria through water, is a threat to global public health. Here, we report Fe-doped ZnO nanoparticles (Fe/ZnO NPs) based solar-photocatalytic disinfection (PCD) of multidrug resistant Escherichia coli (MDR E. coli). Fe/ZnO NPs were synthesized by chemical precipitation technique, and when used as photocatalyst for disinfection, proved to be more effective (time for complete disinfection = 90 min) than ZnO (150 min) and TiO 2 (180 min). Lipid peroxidation and potassium (K + ) ion leakage studies indicated compromisation of bacterial cell membrane and electron microscopy and live-dead staining confirmed the detrimental effects on membrane integrity. Investigations indicated that H 2 O 2 was the key species involved in solar-PCD of MDR E. coli by Fe/ZnO NPs. X-ray diffraction and atomic absorption spectroscopy studies showed that the Fe/ZnO NPs system remained stable during the photocatalytic process. The Fe/ZnO NPs based solar-PCD process proved successful in the disinfection of MDR E. coli in real water samples collected from river, pond and municipal tap. The Fe/ZnO NPs catalyst made from low cost materials and with high efficacy under solar light may have potential for real world applications, to help reduce the spread of resistant bacteria.

ZIF-8 derived hexagonal-like α-Fe2O3/ZnO/Au nanoplates with tunable surface heterostructures for superior ethanol gas-sensing performance

NASA Astrophysics Data System (ADS)

Chen, Ying; Li, Hui; Ma, Qian; Che, Quande; Wang, Junpeng; Wang, Gang; Yang, Ping

2018-05-01

A series of hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with tunable morphologies and superior ethanol gas-sensing performance were successfully synthesized via the facile multi-step reaction processes. Hexagonal-like α-Fe2O3 nanoplates with uniform size around 150 nm are employed as new sensor substrates for loading the well-distributed ZnO and Au nanoparticles with adjustable size distribution on the different surfaces. Brunauer-EmmeQ-Teller (BET) surface areas of α-Fe2O3 and α-Fe2O3/ZnO samples are evaluated to be 37.94 and 61.27 m2/g, respectively, while α-Fe2O3/ZnO/Au composites present the highest value of 79.08 m2/g. These α-Fe2O3-based functional materials can exhibit outstanding sensing properties to ethanol. When the ethanol concentration is 100 ppm, the response value of α-Fe2O3/ZnO/Au composites can reach up to 170, which is 14.6 and 80.3 times higher than that of α-Fe2O3/ZnO and pure α-Fe2O3, respectively. The recycling stability and long-time effectiveness can be availably maintained within 30 days, as well as the response and recovery times are shortened to 4 and 5 s, respectively. Significantly, the response value of α-Fe2O3/ZnO/Au composite is still up to 63 at an operating temperature of 280 °C even though the ethanol concentration decreases to 10 ppm. The enhanced gas sensing mechanism would be focused on the synergistic effects of phase compositions, surface heterogeneous structures, large specific surface area, and the selective depositions of Au nanoparticles in α-Fe2O3/ZnO/Au sensors. The synergistic effect of different surface heterostructures referring to α-Fe2O3/Au and α-Fe2O3/ZnO/Au and their novel electron transport processes on the surfaces are first investigated and discussed in details. It is expected that hexagonal-like α-Fe2O3/ZnO/Au nanoplate heterostructures with excellent sensing performance can be the promising highly-sensitive materials in the actual application for monitoring and detecting ethanol.

Effect of surfactant amount on the morphology and magnetic properties of monodisperse ZnFe{sub 2}O{sub 4} nanoparticles

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

Zhao, Haitao, E-mail: zht95711lunwen@163.com; Liu, Ruiping; Zhang, Qiang

2016-03-15

Graphical abstract: Polyol process to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles. - Highlights: • An one-step, facile and inexpensive synthetic route to monodisperse ZnFe{sub 2}O{sub 4} nanoparticles is described. • The sodium citrate stabilized ZnFe{sub 2}O{sub 4} nanoparticles with a diameter in the 5–8 nm size range can be easily dispersed in water. • The synthesis is very robust in terms of variations of experimental parameters. • ZnFe{sub 2}O{sub 4} nanoparticles present ferrimagnetic behavior at room temperature with a small hysteresis. - Abstract: The spinel ZnFe{sub 2}O{sub 4} ferrites with sodium citrate as a surfactant were fabricated by polyol process. Themore » effect of surfactant amount on the structure, morphology and magnetic properties of ZnFe{sub 2}O{sub 4} ferrites were investigated by X-ray diffraction(XRD), transmission electron microscope (TEM), thermogravimetric and differential scanning calorimetry (TG–DSC) and vibrating sample magnetometry (VSM), respectively. The results indicate that the structure of ZnFe{sub 2}O{sub 4} ferrites is a pure cubic spinel structure with a particle size of 5–8 nm. The dispersion of the synthesized ZnFe{sub 2}O{sub 4} is enhanced when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases. The synthesized particles present ferrimagnetic behavior with a small hysteresis at room temperature. The increase of surfactant amount conversely leads to the decrease in the saturation magnetization value (Ms) especially when the mole ratio of Fe(acac){sub 3} to sodium citrate decreases to 8:3. Its Ms value is drastically reduced to 18.97 emu/g.« less

In-situ synthesized ZnFe2O4 firmly anchored to the surface of MWCNTs as a long-life anode material with high lithium storage performance

NASA Astrophysics Data System (ADS)

Yang, Tianbo; Zhang, Wanxi; Li, Linlin; Jin, Bo; Jin, Enmei; Jeong, Sangmoon; Jiang, Qing

2017-12-01

Because of two different metal cations in the crystal structures, binary transition metal oxides possess a lot of unique properties. ZnFe2O4 emerges from these transition metal oxides on account of its high theoretical capacity (1072 mAh g-1). One-dimensional multi-walled carbon nanotubes (MWCNTs) would be a desirable conductive additive for ZnFe2O4, thereby improving the electrochemical performance of ZnFe2O4. In this work, we prepare ZnFe2O4/MWCNTs by solvothermal method with further heat-treatment. ZnFe2O4 nanoparticles are firmly anchored to the surface of MWCNTs. ZnFe2O4/MWCNTs nanocomposite displays high specific capacity (1278 mAh g-1 at a current density of 200 mA g-1 after 200 cycles, and 565 mAh g-1 at a current density of 1500 mA g-1 after 500 cycles), and good rate performance (367 mAh g-1 even at a current density of 6000 mAh g-1 after 80 cycles). The superior electrochemical performance may promote ZnFe2O4 to be a promising alternative anode in lithium-ion batteries.

Surface complexation and precipitate geometry for aqueous Zn(II) sorption on ferrihydrite I: X-ray absorption extended fine structure spectroscopy analysis

USGS Publications Warehouse

Waychunas, G.A.; Fuller, C.C.; Davis, J.A.

2002-01-01

"Two-line" ferrihydrite samples precipitated and then exposed to a range of aqueous Zn solutions (10-5 to 10-3 M), and also coprecipitated in similar Zn solutions (pH 6.5), have been examined by Zn and Fe K-edge X-ray absorption spectroscopy. Typical Zn complexes on the surface have Zn-O distances of 1.97(0.2) A?? and coordination numbers of about 4.0(0.5), consistent with tetrahedral oxygen coordination. This contrasts with Zn-O distances of 2.11(.02) A?? and coordination numbers of 6 to 7 in the aqueous Zn solutions used in sample preparation. X-ray absorption extended fine structure spectroscopy (EXAFS) fits to the second shell of cation neighbors indicate as many as 4 Zn-Fe neighbors at 3.44(.04) A?? in coprecipitated samples, and about two Zn-Fe neighbors at the same distance in adsorption samples. In both sets of samples, the fitted coordination number of second shell cations decreases as sorption density increases, indicating changes in the number and type of available complexing sites or the onset of competitive precipitation processes. Comparison of our results with the possible geometries for surface complexes and precipitates suggests that the Zn sorption complexes are inner sphere and at lowest adsorption densities are bidentate, sharing apical oxygens with adjacent edge-sharing Fe(O,OH)6 octahedra. Coprecipitation samples have complexes with similar geometry, but these are polydentate, sharing apices with more than two adjacent edge-sharing Fe(O,OH)6 polyhedra. The results are inconsistent with Zn entering the ferrihydrite structure (i.e., solid solution formation) or formation of other Zn-Fe precipitates. The fitted Zn-Fe coordination numbers drop with increasing Zn density with a minimum of about 0.8(.2) at Zn/(Zn + Fe) of 0.08 or more. This change appears to be attributable to the onset of precipitation of zinc hydroxide polymers with mainly tetrahedral Zn coordination. At the highest loadings studied, the nature of the complexes changes further, and a second type of precipitate forms. This has a structure based on a brucite layer topology, with mainly octahedral Zn coordination. Amorphous zinc hydroxide samples prepared for comparison had a closely similar local structure. Analysis of the Fe K-edge EXAFS is consistent with surface complexation reactions and surface precipitation at high Zn loadings with little or no Fe-Zn solid solution formation. The formation of Zn-containing precipitates at solution conditions two or more orders of magnitude below their solubility limit is compared with other sorption and spectroscopic studies that describe similar behavior. Copyright ?? 2002 Elsevier Science Ltd.

Chemical fractionation of metals in wetland sediments: Indiana Dunes National Lakeshore.

PubMed

Dollar, N L; Souch, C J; Filippelli, G M; Mastalerz, M

2001-09-15

Tessier-type (1979) sequential extractions for heavy metals (Cd, Cr, Cu, Fe, Mn, Pb, and Zn) were conducted on sediments from two wetland sites, one inundated and the other drained, within the Indiana Dunes National Lakeshore (IDNL), NW Indiana, with the objective of (i) evaluating extraction techniques on organic-rich sediments, (ii) determining the geochemistry and mobility of potentially biotoxic trace metals in a contaminated environment, and (iii) considering the implications of different restoration strategies on the potential for heavy metal remobilization. Long and repeated extractions were needed to effectively degrade the organic-rich sediments (up to 75% of the sediment by mass). Analysis of sulfur fractionation revealed that it was predominantly sequestered along with the organically bound fraction (renamed oxidizable). Metal recovery was good with the sum of the extractant steps typically within 20% of the total metal concentration determined after total microwave digestion. Results showed metal fractionation to be both metal- and site-specific, The oxidizable fraction is dominant for Cu, Cr, and Fe (>65% of the nonresidual fraction for almost all samples) and overall is most important also for Cd and Pb. The iron/manganese oxide fraction is important for Pb, Mn, and Zn, particularly at the drained site. The carbonate bound fraction is relatively insignificant at both sites, except for Cd and Mn, although it is more important at the drained site. The exchangeable fraction is significant in the uppermost sediments at the drained site, particularly for Cd (3-24%), Pb (3-14%), and Zn (36-45%); whereas, for the inundated site, it ranged only from 0 to 1% Zn, with no detectable Cd or Pb. Chromium, Cu, and Fe exist in forms not likely to be remobilized, whereas Cd, Mn, Pb, and Zn are potentially mobile if drained wetland sites are reflooded (and pH and redox potential altered). Simple mass balance calculations illustrate the potential for the removal of approximately 84,375 kg of exchangeable Zn if currently drained sites across the IDNL are reflooded, with concentrations in water draining into Lake Michigan as high as 5 ppm.

Structural classification of RAO/sub 3/(MO)/sub n/ compounds (R = Sc, In, Y, or lanthanides; A = Fe(III), Ga, Cr, or Al; M = divalent cation; n = 1-11)

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

Kimizuka, N.; Mohri, T.

A series of new compounds (RAO/sub 3/MO)/sub n/ (n = 1-11) having spinel, YbFe/sub 2/O/sub 4/, or InFeO/sub 3/(ZnO)/sub n/ types of structures were newly synthesized (R = Sc, In, Y, Lu, Yb, Tm, or Er; A = Fe(III), Ga, Cr, or Al; M = Mg, Mn, Fe(II), Co, Ni, Zn, or Cd) at elevated temperatures. The conditions of synthesis and the lattice constants for these compounds are reported. The stacking sequences of the InO/sub 1.5/, (FeZn)O/sub 2.5/, and ZnO layers for InFeO/sub 3/(ZnO)/sub 10/ and the TmO/sub 1.5/, (AlZn)O/sub 2.5/, and ZnO layers for TmAlO/sub 3/(ZnO)/sub 11/ are presented,more » respectively. The crystal structures of the (RAO/sub 3/)/sub m/(MO)/sub n/ phases R = Sc, In, Y, or lanthanide elements; A = Fe(III), Ga, Cr, or Al; M = divalent cation elements; m and n = integer are classified into four crystal structure types (K/sub 2/NiF/sub 4/, CaFe/sub 2/O/sub 4/, YbFe/sub 2/O/sub 4/, and spinel), based upon the constituent cations R, A, and M.« less

Consumption of galacto-oligosaccharides increases iron absorption from a micronutrient powder containing ferrous fumarate and sodium iron EDTA: a stable-isotope study in Kenyan infants.

PubMed

Paganini, Daniela; Uyoga, Mary A; Cercamondi, Colin I; Moretti, Diego; Mwasi, Edith; Schwab, Clarissa; Bechtler, Salome; Mutuku, Francis M; Galetti, Valeria; Lacroix, Christophe; Karanja, Simon; Zimmermann, Michael B

2017-10-01

Background: Whether consumption of prebiotics increases iron absorption in infants is unclear. Objective: We set out to determine whether prebiotic consumption affects iron absorption from a micronutrient powder (MNP) containing a mixture of ferrous fumarate and sodium iron EDTA (FeFum+NaFeEDTA) in Kenyan infants. Design: Infants ( n = 50; aged 6-14 mo) consumed maize porridge that was fortified with an MNP containing FeFum+NaFeEDTA and 7.5 g galacto-oligosaccharides (GOSs) (Fe+GOS group, n = 22) or the same MNP without GOSs (Fe group, n = 28) each day for 3 wk. Then, on 2 consecutive days, we fed all infants isotopically labeled maize porridge and MNP test meals containing 5 mg Fe as 57 FeFum+Na 58 FeEDTA or ferrous sulfate ( 54 FeSO 4 ). Iron absorption was measured as the erythrocyte incorporation of stable isotopes. Iron markers, fecal pH, and bacterial groups were assessed at baseline and 3 wk. Comparisons within and between groups were done with the use of mixed-effects models. Results: There was a significant group-by-compound interaction on iron absorption ( P = 0.011). The median percentages of fractional iron absorption from FeFum+NaFeEDTA and from FeSO 4 in the Fe group were 11.6% (IQR: 6.9-19.9%) and 20.3% (IQR: 14.2-25.7%), respectively, ( P < 0.001) and, in the Fe+GOS group, were 18.8% (IQR: 8.3-37.5%) and 25.5% (IQR: 15.1-37.8%), respectively ( P = 0.124). Between groups, iron absorption was greater from the FeFum+NaFeEDTA ( P = 0.047) in the Fe+GOS group but not from the FeSO 4 ( P = 0.653). The relative iron bioavailability from FeFum+NaFeEDTA compared with FeSO 4 was higher in the Fe+GOS group than in the Fe group (88% compared with 63%; P = 0.006). There was a significant time-by-group interaction on Bifidobacterium spp. ( P = 0.008) and Lactobacillus / Pediococcus / Leuconostoc spp. ( P = 0.018); Lactobacillus / Pediococcus / Leuconostoc spp. decreased in the Fe group ( P = 0.013), and there was a nonsignificant trend toward higher Bifidobacterium spp. in the Fe+GOS group ( P = 0.099). At 3 wk, iron absorption was negatively correlated with fecal pH ( P < 0.001) and positively correlated with Lactobacillus / Pediococcus / Leuconostoc spp. ( P = 0.001). Conclusion: GOS consumption by infants increased iron absorption by 62% from an MNP containing FeFum+NaFeEDTA, thereby possibly reflecting greater colonic iron absorption. This trial was registered at clinicaltrials.gov as NCT02666417. © 2017 American Society for Nutrition.

Novel Flaxseed Gum Nanocomposites Are Slow Release Iron Supplements.

PubMed

Liang, Shan; Huang, Yu; Shim, Youn Young; Ma, Xiang; Reaney, Martin J T; Wang, Yong

2018-05-23

Nanocomposites, based on iron salts and soluble flaxseed gum (FG), were prepared as potential treatments of iron deficiency anemia (IDA). FG was extracted, characterized, and formulated into iron-loading nanocomposites via ion-exchange against FeCl 3 , Fe 2 (SO 4 ) 3 , FeCl 2 , and FeSO 4 ·7H 2 O. FG-iron nanocomposites preparation condition was optimized, and physicochemical properties of the nanocomposites were investigated. In vitro release kinetics of iron in simulated gastric fluid (SGF) was also evaluated. FG heteropolysaccharide, consisting of rhamnose (33.73%), arabinose (24.35%), xylose (14.23%), glucose (4.54%), and galactose (23.15%) monosaccharides, linked together via varieties of glycosidic bonds, was a good recipient for both ferric and ferrous irons under screened conditions (i.e., 80 °C, 2 h, I/G = 1:2). Iron loaded contents in the nanocomposites prepared from FG-FeCl 3 , FG-Fe 2 (SO 4 ) 3 , FG-FeCl 2 , and FG-FeSO 4 ·7H 2 O were 25.51%, 10.36%, 5.83%, and 22.83%, respectively. Iron in these nanocomposites was mostly in a bound state, especially in FG-FeCl 3 , due to chelation forming bonds between iron and polysaccharide hydroxyl or carboxyl groups and formed stable polysaccharide-iron crystal network structures. Free iron ions were effectively removed by ethanol treatments. Because of chelation, the nanocomposites delayed iron release in SGF and the release kinetics were consistent with Korsmeyer-Peppas model. This indicates that such complexes might reduce side effects of free iron in human stomach. Altogether, this study indicates that these synthetic FG-iron nanocomposites might be developed as novel iron supplements for iron deficiency, in which FG-FeCl 3 is considered as the best option.

Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis.

PubMed

Li, Shanshan; Zhang, Chen; Wang, Meng; Li, Yu

2014-01-01

Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13%. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (-1.072 and -24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.

Effect of thermal annealing on the structure and magnetism of Fe-doped ZnO nanocrystals synthesized by solid state reaction

NASA Astrophysics Data System (ADS)

Wang, Dong; Chen, Z. Q.; Wang, D. D.; Gong, J.; Cao, C. Y.; Tang, Z.; Huang, L. R.

2010-11-01

High purity Fe 2O 3/ZnO nanocomposites were annealed in air at different temperatures between 100 and 1200 °C to get Fe-doped ZnO nanocrystals. The structure and grain size of the Fe 2O 3/ZnO nanocomposites were investigated by X-ray diffraction 2θ scans. Annealing induces an increase of the grain size from 25 to 195 nm and appearance of franklinite phase of ZnFe 2O 4. Positron annihilation measurements reveal large number of vacancy defects in the interface region of the Fe 2O 3/ZnO nanocomposites, and they are gradually recovered with increasing annealing temperature. After annealing at temperatures higher than 1000 °C, the number of vacancies decreases to the lower detection limit of positrons. Room temperature ferromagnetism can be observed in Fe-doped ZnO nanocrystals using physical properties measurement system. The ferromagnetism remains after annealing up to 1000 °C, suggesting that it is not related with the interfacial defects.

A Nanoparticulate Ferritin-Core Mimetic Is Well Taken Up by HuTu 80 Duodenal Cells and Its Absorption in Mice Is Regulated by Body Iron12

PubMed Central

Latunde-Dada, Gladys O; Pereira, Dora IA; Tempest, Bethan; Ilyas, Hibah; Flynn, Angela C; Aslam, Mohamad F; Simpson, Robert J; Powell, Jonathan J

2014-01-01

Background: Iron (Fe) deficiency anemia remains the largest nutritional deficiency disorder worldwide. How the gut acquires iron from nano Fe(III), especially at the apical surface, is incompletely understood. Objective: We developed a novel Fe supplement consisting of nanoparticulate tartrate-modified Fe(III) poly oxo-hydroxide [here termed nano Fe(III)], which mimics the Fe oxide core of ferritin and effectively treats iron deficiency anemia in rats. Methods: We determined transfer to the systemic circulation of nano Fe(III) in iron-deficient and iron-sufficient outbread Swiss mouse strain (CD1) mice with use of 59Fe-labeled material. Iron deficiency was induced before starting the Fe-supplementation period through reduction of Fe concentrations in the rodent diet. A control group of iron-sufficient mice were fed a diet with adequate Fe concentrations throughout the study. Furthermore, we conducted a hemoglobin repletion study in which iron-deficient CD1 mice were fed for 7 d a diet supplemented with ferrous sulfate (FeSO4) or nano Fe(III). Finally, we further probed the mechanism of cellular acquisition of nano Fe(III) by assessing ferritin formation, as a measure of Fe uptake and utilization, in HuTu 80 duodenal cancer cells with targeted inhibition of divalent metal transporter 1 (DMT1) and duodenal cytochrome b (DCYTB) before exposure to the supplemented iron sources. Differences in gene expression were assessed by quantitative polymerase chain reaction. Results: Absorption (means ± SEMs) of nano Fe(III) was significantly increased in iron-deficient mice (58 ± 19%) compared to iron-sufficient mice (18 ± 17%) (P = 0.0001). Supplementation of the diet with nano Fe(III) or FeSO4 significantly increased hemoglobin concentrations in iron-deficient mice (170 ± 20 g/L, P = 0.01 and 180 ± 20 g/L, P = 0.002, respectively). Hepatic hepcidin mRNA expression reflected the nonheme-iron concentrations of the liver and was also comparable for both nano Fe(III)– and FeSO4-supplemented groups, as were iron concentrations in the spleen and duodenum. Silencing of the solute carrier family 11 (proton-coupled divalent metal ion transporter), member 2 (Slc11a2) gene (DMT1) significantly inhibited ferritin formation from FeSO4 (P = 0.005) but had no effect on uptake and utilization of nano Fe(III). Inhibiting DCYTB with an antibody also had no effect on uptake and utilization of nano Fe(III) but significantly inhibited ferritin formation from ferric nitrilotriacetate chelate (Fe-NTA) (P = 0.04). Similarly, cellular ferritin formation from nano Fe(III) was unaffected by the Fe(II) chelator ferrozine, which significantly inhibited uptake and utilization from FeSO4 (P = 0.009) and Fe-NTA (P = 0.005). Conclusions: Our data strongly support direct nano Fe(III) uptake by enterocytes as an efficient mechanism of dietary iron acquisition, which may complement the known Fe(II)/DMT1 uptake pathway. PMID:25342699

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

NASA Astrophysics Data System (ADS)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Health risk assessment of heavy metal variability in sachet water sold in Ado-Odo Ota, South-Western Nigeria.

PubMed

Emenike, PraiseGod Chidozie; Tenebe, Theophilus Imokhai; Omeje, Maxwell; Osinubi, Damilare Samuel

2017-08-31

The sales of sachet water (SW), also known as "pure water" (PW), in Nigeria is a lucrative business. It serves many people, especially low-income earners, by providing a more affordable access to safe drinking water when compared with table water. However, some of the producers of SW do not effectively treat raw water before packaging them for sale. This study investigates the presence and concentrations of heavy metals, such as chromium (Cr), iron (Fe), manganese (Mn), copper (Cu), aluminum (Al), and zinc (Zn) in some samples of SW sold within Ota, Ogun State, Nigeria. Samples of SW from nine different producers were purchased for four consecutive weeks and analyzed to determine the concentrations of these heavy metals in them. Furthermore, health risk indicators, such as chronic daily intake (CDI) and health risk indices (HRI) for children and adults, were calculated separately. The metal concentrations were compared with allowable limits set by the World Health Organization (WHO), Nigerian Industrial Standard (NIS), and the United States Environmental Protection Agency (US EPA). High concentrations of Cr, Fe, and Al were found in all the nine samples and exceeded the maximum allowable limits (MAL) of all the standards considered. However, the concentrations of Zn, Mn, and Cu were within permissible limits. The HRIs of heavy metals were in the order of Cu > Fe > Zn > Mn > Al > Cr, but since the standard limits set for some metals were exceeded, proper and effective treatment is required to safeguard the health of consumers.

Evaluation of the effect of sulfate, alkalinity and disinfector on iron release of iron pipe and iron corrosion scale characteristics under water quality changing condition using response surface methodology

NASA Astrophysics Data System (ADS)

Yang, Fan; Shi, Baoyou; Zhang, Weiyu; Guo, Jianbo; Wu, Nana; Liu, Xinyuan

2018-02-01

The response surface methodology (RSM), particularly Box-Behnken design model, was used in this study to evaluate the sulfate, alkalinity and free chlorine on iron release of pipe with groundwater supply history and its iron corrosion scale characteristics under water quality changing experiment. The RSM results together with response surface contour plots indicated that the iron release of pipe section reactors was positively related with Larson Ratio and free chlorine. The thin Corrosion scales with groundwater supply history upon collection site contained Fe3O4 (18%), α-FeOOH (64%), FeCO3 (9%), β-FeOOH (8%) and γ-FeOOH (5%), besides their averaged amorphous iron oxide content was 13.6%. After the RSM water quality changing experiment, Fe3O4, amorphous iron oxide and intermediate iron products (FeCO3, Green Rust (GR)) content on scale of Cl2Rs increased, while their α-FeOOH contents decreased and β-FeOOH disappeared. The high iron released Cl2Rs receiving higher LR water (1.40-2.04) contained highest FeCO3 (20%) and amorphous iron oxide (42%), while the low iron release Cl2Rs receiving lower LR water (0.52-0.73) had higher GR(6.5%) and the amorphous iron oxide (23.7%). In high LR water (>0.73), the thin and non-protective corrosion scale containing higher amorphous iron oxide, Fe(II) derived from new produced Fe3O4 or FeCO3 or GR was easy for oxidants and sulfate ions penetration, and had higher iron release. However the same unstable corrosion scale didn’t have much iron release in low LR water (≤0.73). RSM experiment indicated that iron release of these unstable corrosion scales had close relationship with water quality (Larson Ratio and disinfectant). Optimizing the water quality of new source water and using reasonable water purification measures can help to eliminate the red water case.

Faunal composition and organic surface encrustations at hydrothermal vents on the southern Juan De Fuca Ridge

NASA Astrophysics Data System (ADS)

Tunnicliffe, Verena; Fontaine, A. R.

1987-10-01

Examination of a small collection of macroinvertebrates from three vents of the southern Juan de Fuca vent field reveals differences between the vents with respect to species composition, species habits, and microbial and metallic deposits on their surfaces. TWo apparently new vestimentiferan species were found, and for the first time the Juan de Fuca palm worm was observed to dwell on smokers. High acidity values recorded in this system may interfere with the process of shell calcification in an archaeogastropod snail. The surfaces of vestimentifer an tubes at two vents are heavily encrusted with microbial and metallic accumulations. Scanning electron microscope, transmission electron microscope, and energy dispersive X ray microanalysis observations show that iron-based crusts on orange tubes are built from accumulations of an Fe-rich particle of distinctive size and shape. Morphological evidence is presented for the microbial origin of Fe-rich particles. Zn-rich particles found on black tubes are not of microbial origin. We suggest that iron deposition on surfaces in the vent environment is initially biocatalytic but subsequent deposits may build by simple inorganic reactions.

Adsorptive removal of catalyst poisons from coal gas for methanol synthesis

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

Bhatt, B.L.; Golden, T.C.; Hsiung, T.H.

1991-12-01

As an integral part of the liquid-phase methanol (LPMEOH) process development program, the present study evaluated adsorptive schemes to remove traces of catalyst poisons such as iron carbonyl, carbonyl sulfide, and hydrogen sulfide from coal gas on a pilot scale. Tests were conducted with coal gas from the Cool Water gasification plant at Daggett, California. Iron carbonyl, carbonyl sulfide, and hydrogen sulfide were effectively removed from the coal gas. The adsorption capacities of Linde H-Y zeolite and Calgon BPL carbon for Fe(CO){sub 5} compared well with previous bench-scale results at similar CO{sub 2} partial pressure. Adsorption of COS by Calgonmore » FCA carbon appeared to be chemical and nonregenerable by thermal treatment in nitrogen. A Cu/Zn catalyst removed H{sub 2}S very effectively. With the adsorption system on-line, a methanol catalyst showed stable activity during 120 h operation, demonstrating the feasibility of adsorptive removal of trace catalyst poisons from the synthesis gas. Mass transfer coefficients were estimated for Fe(CO){sub 5} and COS removal which can be directly used for design and scale up.« less

New insights into hydrothermal vent processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece

PubMed Central

Kilias, Stephanos P.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N.; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J.; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael

2013-01-01

We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the hydrothermal vent field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor hydrothermal activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on hydrothermal ammonia and CO2. Our findings highlight that acidic shallow-submarine hydrothermal vents nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe3+-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe2+-oxidation, dependent on microbially produced nitrate. PMID:23939372

The environmental impacts of one of the largest tailing dam failures worldwide.

PubMed

Hatje, Vanessa; Pedreira, Rodrigo M A; de Rezende, Carlos Eduardo; Schettini, Carlos Augusto França; de Souza, Gabriel Cotrim; Marin, Danieli Canaver; Hackspacher, Peter Christian

2017-09-06

The impacts of the SAMARCO iron tailing spill along more than 650 km, between the dam and the plume of the Doce River in the Atlantic, were assessed by the determination of toxic metals. The tailing spill caused a substantial increase in suspended sediment loads (up to 33,000 mg L -1 ), in addition to large depositions of waste along the Doce basin. The highest estimated transport of dissolved metals was observed for Fe (58.8 μg s -1 ), Ba (37.9 μg s -1 ) and Al (25.0 μg s -1 ). Sediments reached the highest enrichment factors (EFs) for Hg (4,234), Co (133), Fe (43), and Ni (16), whereas As (55), Ba (64), Cr (16), Cu (17), Mn (41), Pb (38) and Zn (82) highest EFs were observed for suspended particulate matter (SPM). Iron, As, Hg, Mn exceeded sediment quality guidelines. Therefore, the risk of occurrence of adverse effects is highly possible, not only due to the dam failure, but also due to the Fe mining and the artisan Au mining. Heavy rain episodes will likely cause enhanced erosion, remobilization, and transport of contaminated particles, sustaining high inputs of SPM and metals for the years to come and threatening the ecosystem services.

Compendium of Shock Wave Data. Volume 1. Revision 1. Introduction. Section A1-Elements

DTIC Science & Technology

1977-06-01

the limited character list of the automatic printer that produced these pages. Therefore, V0 is written as VO, Ci as CL, etc. While the above...14-1 Sodium carbonate Na 2 CO3 99-23-1 Note that the automatic printer used for the data pages is restricted to capital letters, so that the molecular...SILICON St O.Z5 WT PERCENT MAX. IRON FE 0.35 - - - 4 COPPER Cu 0.05 - - - ( MANGANESE MN 0.03 - - - MAGNESIUM Ŕ 0.03 - - - ZINK ZN 0.05 - - - TITANIUM

New approach towards the polyol route to fabricate MFe2O4 magnetic nanoparticles: The use of MCl2 and Fe(acac)3 as chemical precursors

NASA Astrophysics Data System (ADS)

Solano, Eduardo; Yáñez, Ramón; Ricart, Susagna; Ros, Josep

2015-05-01

A new more efficient approach of the polyol route to generate MFe2O4 (M=Mn, Fe, Co, Ni, Cu, Zn) nanoparticles in triethylene glycol (TREG) is presented. The selected thermal procedure is based on the Fe metalorganic precursor (iron(III) acetylacetonate) decomposition in presence of an inorganic transition metal chloride salt (MCl2, M=Mn, Fe, Co, Ni, Cu, Zn) to produce high quality polar dispersible nanoparticles with lower production cost. In addition, the nanoparticles are stabilized by ionic (from the Cl-) and steric (TREG as capping ligand) effects inducing into the nanoparticles an extraordinary stability in different polar solvents. As result of this optimized methodology, the colloidal polar dispersible nanoparticles present a size around 10 nm with an adequate size dispersion demonstrated by analyzing transmission electron microscopy (TEM) images. X-ray powder diffraction (XRPD) results corroborate the absence of secondary phases and the high crystalline degree obtained for the spinel structure, fact proved by using synchrotron X-ray diffraction. The high magnetic performance at low and room temperature of the nanoparticles studied by magnetometry proves the high internal crystal order of the spinel. Parallel to this, the influence of the heating ramp and annealing time in the thermal procedure were also investigated for the CuFe2O4 case, where a relationship between these two parameters and the final size and their associated diameter distribution was found, allowing a possible size control of the final ferrite magnetic nanoparticles synthesized.

Synthesis and characterization of Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO nanocomposites from waste batteries for photocatalytic, electrochemical and thermal studies

NASA Astrophysics Data System (ADS)

Mylarappa, M.; Venkata Lakshmi, V.; Vishnu Mahesh, K. R.; Nagaswarupa, H. P.; Raghavendra, N.

2017-11-01

In the present paper, Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO composites recovered from waste batteries using acid dissolution and ferrite processing were studied. The recovered Mn-ZnFe2O4 nanocomposites were decorated onto rGO using the facile hydrothermal method. The recovered material was characterized using x-ray powder diffraction to study the particle size and crystallinity. The morphology of the composites was analyzed using scanning electron microscopy, and elements present in the materials were studied using energy dispersive x-ray analysis. The functional groups attached were observed using a Fourier transform infrared spectrometer. Furthermore, the recovered composites were evaluated in thermal studies using thermal gravimetric analysis, differential scanning calorimetry and dynamic thermal analysis. The material was used as a photocatalyst for the removal of acid orange 88 dye, and as an electrocatalyst. The decreased band gap energy for the Mn-ZnFe2O4/rGO composite was displayed in better photocatalytic activity for a given reaction. The electrochemical properties of Mn-ZnFe2O4 and Mn-ZnFe2O4/rGO have been investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with a paste-type electrode. The CV indicated the reversibility of the electrode reaction, and the EIS revealed that a decrease in the charge transfer resistance increases the double layer capacitance of the rGO/Mn-ZnFe2O4 electrode.

Hierarchical heterostructures of p-type bismuth oxychloride nanosheets on n-type zinc ferrite electrospun nanofibers with enhanced visible-light photocatalytic activities and magnetic separation properties.

PubMed

Sun, Yucong; Shao, Changlu; Li, Xinghua; Guo, Xiaohui; Zhou, Xuejiao; Li, Xiaowei; Liu, Yichun

2018-04-15

P-type bismuth oxychloride (p-BiOCl) nanosheets were uniformly grown on n-type zinc ferrite (n-ZnFe 2 O 4 ) electrospun nanofibers via a solvothermal technique to form hierarchical heterostructures of p-BiOCl/n-ZnFe 2 O 4 (p-BiOCl/n-ZnFe 2 O 4 H-Hs). The density and loading amounts of the BiOCl nanosheets with exposed {0 0 1} facets were easily controlled by adjusting the reactant concentration in the solvothermal process. The p-BiOCl/n-ZnFe 2 O 4 H-Hs exhibited enhanced visible-light photocatalytic activities for the degradation of Rhodamine B (RhB). The apparent first-order rate of the p-BiOCl/n-ZnFe 2 O 4 H-Hs and its normalized constant were about 12.6- and 8-fold higher than pure ZnFe 2 O 4 nanofibers. This suggests that both the improved charge separation efficiency from the uniform p-n heterojunctions and the enlarged active surface sites from the hierarchical structures increase the photocatalytic performances. Furthermore, the p-BiOCl/n-ZnFe 2 O 4 H-Hs could be efficiently separated from the solution with an external magnetic field via the ferromagnetic behavior of ZnFe 2 O 4 nanofibers. The magnetic p-BiOCl/n-ZnFe 2 O 4 H-Hs with enhanced visible-light photocatalytic performances might have potential applications in water treatment. Copyright © 2018. Published by Elsevier Inc.

Oxygen vacancy induced by La and Fe into ZnO nanoparticles to modify ferromagnetic ordering

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

Verma, Kuldeep Chand, E-mail: kuldeep0309@yahoo.co.in; Kotnala, R.K., E-mail: rkkotnala@gmail.com

We reported long-range ferromagnetic interactions in La doped Zn{sub 0.95}Fe{sub 0.05}O nanoparticles that mediated through lattice defects or vacancies. Zn{sub 0.92}Fe{sub 0.05}La{sub 0.03}O (ZFLaO53) nanoparticles were synthesized by a sol–gel process. X-ray fluorescence spectrum of ZFLaO53 detects the weight percentage of Zn, Fe, La and O. X-ray diffraction shows the hexagonal Wurtzite ZnO phase. The Rietveld refinement has been used to calculate the lattice parameters and the position of Zn, Fe, La and O atoms in the Wurtzite unit cell. The average size of ZFLaO53 nanoparticles is 99 nm. The agglomeration type product due to OH ions with La resultsmore » into ZnO nanoparticles than nanorods that found in pure ZnO and Zn{sub 0.95}Fe{sub 0.05}O sample. The effect of doping concentration to induce Wurtzite ZnO structure and lattice defects has been analyzed by Raman active vibrational modes. Photoluminescence spectra show an abnormal emission in both UV and visible region, and a blue shift at near band edge is formed with doping. The room temperature magnetic measurement result into weak ferromagnetism but pure ZnO is diamagnetic. However, the temperature dependent magnetic measurement using zero-field and field cooling at dc magnetizing field 500 Oe induces long-range ferromagnetic ordering. It results into antiferromagnetic Neel temperature of ZFLaO53 at around 42 K. The magnetic hysteresis is also measured at 200, 100, 50 and 10 K measurement that indicate enhancement in ferromagnetism at low temperature. Overall, the La doping into Zn{sub 0.95}Fe{sub 0.05}O results into enhanced antiferromagnetic interaction as well as lattice defects/vacancies. The role of the oxygen vacancy as the dominant defects in doped ZnO must form Bound magnetic polarons has been described. - Graphical abstract: The long-range ferromagnetic order in Zn{sub 0.92}Fe{sub 0.05}La{sub 0.03}O nanoparticles at low temperature measurements involves oxygen vacancy as the medium of magnetic interactions. - Highlights: • The La and Fe doping into ZnO nanoparticles induce defects in terms of oxygen vacancy. • The La ions in Fe substituted ZnO formed nanoparticles than nanorods. • Antiferromagnetic interactions are observed at room temperature magnetic measurement. • Rietveld analysis evaluated structural deformation in the Wurtzite ZnO lattice.« less

Iron isotope fractionation during microbially stimulated Fe(II) oxidation and Fe(III) precipitation

USGS Publications Warehouse

Balci, N.; Bullen, T.D.; Witte-Lien, K.; Shanks, Wayne C.; Motelica, M.; Mandernack, K.W.

2006-01-01

Interpretation of the origins of iron-bearing minerals preserved in modern and ancient rocks based on measured iron isotope ratios depends on our ability to distinguish between biological and non-biological iron isotope fractionation processes. In this study, we compared 56Fe/54Fe ratios of coexisting aqueous iron (Fe(II)aq, Fe(III)aq) and iron oxyhydroxide precipitates (Fe(III)ppt) resulting from the oxidation of ferrous iron under experimental conditions at low pH (<3). Experiments were carried out using both pure cultures of Acidothiobacillus ferrooxidans and sterile controls to assess possible biological overprinting of non-biological fractionation, and both SO42- and Cl- salts as Fe(II) sources to determine possible ionic/speciation effects that may be associated with oxidation/precipitation reactions. In addition, a series of ferric iron precipitation experiments were performed at pH ranging from 1.9 to 3.5 to determine if different precipitation rates cause differences in the isotopic composition of the iron oxyhydroxides. During microbially stimulated Fe(II) oxidation in both the sulfate and chloride systems, 56Fe/54Fe ratios of residual Fe(II)aq sampled in a time series evolved along an apparent Rayleigh trend characterized by a fractionation factor ??Fe(III)aq-Fe(II)aq???1.0022. This fractionation factor was significantly less than that measured in our sterile control experiments (???1.0034) and that predicted for isotopic equilibrium between Fe(II)aq and Fe(III)aq (???1.0029), and thus might be interpreted to reflect a biological isotope effect. However, in our biological experiments the measured difference in 56Fe/54Fe ratios between Fe(III)aq, isolated as a solid by the addition of NaOH to the final solution at each time point under N2-atmosphere, and Fe(II)aq was in most cases and on average close to 2.9??? (??Fe(III)aq-Fe(II)aq ???1.0029), consistent with isotopic equilibrium between Fe(II)aq and Fe(III)aq. The ferric iron precipitation experiments revealed that 56Fe/54Fe ratios of Fe(III)aq were generally equal to or greater than those of Fe(III)ppt, and isotopic fractionation between these phases decreased with increasing precipitation rate and decreasing grain size. Considered together, the data confirm that the iron isotope variations observed in our microbial experiments are primarily controlled by non-biological equilibrium and kinetic factors, a result that aids our ability to interpret present-day iron cycling processes but further complicates our ability to use iron isotopes alone to identify biological processing in the rock record. ?? 2005 Elsevier Inc. All rights reserved.

Characteristics of iron corrosion scales and water quality variations in drinking water distribution systems of different pipe materials.

PubMed

Li, Manjie; Liu, Zhaowei; Chen, Yongcan; Hai, Yang

2016-12-01

Interaction between old, corroded iron pipe surfaces and bulk water is crucial to the water quality protection in drinking water distribution systems (WDS). Iron released from corrosion products will deteriorate water quality and lead to red water. This study attempted to understand the effects of pipe materials on corrosion scale characteristics and water quality variations in WDS. A more than 20-year-old hybrid pipe section assembled of unlined cast iron pipe (UCIP) and galvanized iron pipe (GIP) was selected to investigate physico-chemical characteristics of corrosion scales and their effects on water quality variations. Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Inductively Coupled Plasma (ICP) and X-ray Diffraction (XRD) were used to analyze micromorphology and chemical composition of corrosion scales. In bench testing, water quality parameters, such as pH, dissolved oxygen (DO), oxidation reduction potential (ORP), alkalinity, conductivity, turbidity, color, Fe 2+ , Fe 3+ and Zn 2+ , were determined. Scale analysis and bench-scale testing results demonstrated a significant effect of pipe materials on scale characteristics and thereby water quality variations in WDS. Characteristics of corrosion scales sampled from different pipe segments show obvious differences, both in physical and chemical aspects. Corrosion scales were found highly amorphous. Thanks to the protection of zinc coatings, GIP system was identified as the best water quality stability, in spite of high zinc release potential. It is deduced that the complicated composition of corrosion scales and structural break by the weld result in the diminished water quality stability in HP system. Measurement results showed that iron is released mainly in ferric particulate form. Copyright © 2016 Elsevier Ltd. All rights reserved.

Monodisperse Zn-doped Fe3O4 formation and photo-Fenton activity for degradation of rhodamine B in water

NASA Astrophysics Data System (ADS)

Cen, Huoshi; Nan, Zhaodong

2018-10-01

Zn-doped Fe3O4 can be used as a catalyst in the photo-Fenton process to degrade dye molecules dissolved in water, in which cluster-shaped Zn-doped Fe3O4 (CSZnFe) was synthesized. To enhance the catalytic activity, monodisperse Zn-doped Fe3O4 (MZnFe) was facilely synthesized by a modified solvothermal method through replacement of sodium acetate by urea as a base. The particle size of MZnFe was about 9-16 nm. MZnFe exhibits a larger surface area and higher photo-Fenton catalytic activity for degradation of rhodamine B in water than CSZnFe. Additionally, MZnFe exhibits high saturation magnetization (about 80 emu/g), which is very convenient for separation of MZnFe from solution by a magnet. The growth processes for MZnFe were proposed on the basis of results from in situ calorimetry and other techniques, which indicated different formation mechanisms for MZnFe and CSZnFe.

Ingestion of insoluble dietary fibre increased zinc and iron absorption and restored growth rate and zinc absorption suppressed by dietary phytate in rats.

PubMed

Hayashi, K; Hara, H; Asvarujanon, P; Aoyama, Y; Luangpituksa, P

2001-10-01

We examined the effects of ingestion of five types of insoluble fibre on growth and Zn absorption in rats fed a marginally Zn-deficient diet (6.75 mg (0.103 mmol) Zn/kg diet) with or without added sodium phytate (12.6 mmol/kg diet). The types of insoluble fibre tested were corn husks, watermelon skin, yam-bean root (Pachyrhizus erosus) and pineapple core, and cellulose was used as a control (100 g/kg diet). Body-weight gain in the cellulose groups was suppressed by 57 % by feeding phytate. Body-weight gain in phytate-fed rats was 80 % greater in the watermelon skin fibre and yam-bean root fibre group than that in the cellulose group. Zn absorption ratio in the cellulose groups was lowered by 46 and 70 % in the first (days 7-10) and second (days 16-19) measurement periods with feeding phytate. In the rats fed the phytate-containing diets, Zn absorption ratio in the watermelon skin, yam-bean root and pineapple core fibre groups was 140, 80 and 54 % higher respectively than that in the cellulose group, in the second period. Fe absorption was not suppressed by phytate, however, feeding of these three types of fibre promoted Fe absorption in rats fed phytate-free diets. The concentration of soluble Zn in the caecal contents in the watermelon skin fibre or yam-bean root fibre groups was identical to that in the control group in spite of a higher short-chain fatty acid concentration and lower pH in the caecum. These findings indicate that ingestion of these types of insoluble fibre recovered the growth and Zn absorption suppressed by feeding a high level of phytate, and factors other than caecal fermentation may also be involved in this effect of insoluble fibre.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings.

PubMed

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A H

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal.

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings

PubMed Central

Huang, Longbin; Li, Xiaofang; Nguyen, Tuan A. H.

2015-01-01

Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (FeO and Fed), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS2), ankerite (Ca(Fe Mg)(CO3)2 and siderite (FeCO3), as indicated by the extractable FeO values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal. PMID:26295582

Soybean Fe-S cluster biosynthesis regulated by external iron or phosphate fluctuation.

PubMed

Qin, Lu; Wang, Meihuan; Chen, Liyu; Liang, Xuejiao; Wu, Zhigeng; Lin, Zhihao; Zuo, Jia; Feng, Xiangyang; Zhao, Jing; Liao, Hong; Ye, Hong

2015-03-01

Iron and phosphorus are essential for soybean nodulation. Our results suggested that the deficiency of Fe or P impairs nodulation by affecting the assembly of functional iron-sulfur cluster via different mechanisms. Iron (Fe) and phosphorus (P) are important mineral nutrients for soybean and are indispensable for nodulation. However, it remains elusive how the pathways of Fe metabolism respond to the fluctuation of external Fe or P. Iron is required for the iron-sulfur (Fe-S) cluster assembly in higher plant. Here, we investigated the expression pattern of Fe-S cluster biosynthesis genes in the nodulated soybean. Soybean genome encodes 42 putative Fe-S cluster biosynthesis genes, which were expressed differently in shoots and roots, suggesting of physiological relevance. Nodules initiated from roots of soybean after rhizobia inoculation. In comparison with that in shoots, iron concentration was three times higher in nodules. The Fe-S cluster biosynthesis genes were activated and several Fe-S protein activities were increased in nodules, indicating that a more effective Fe-S cluster biosynthesis is accompanied by nodulation. Fe-S cluster biosynthesis genes were massively repressed and some Fe-S protein activities were decreased in nodules by Fe deficiency, leading to tiny nodules. Notably, P deficiency induced a similar Fe-deficiency response in nodules, i.e, certain Fe-S enzyme activity loss and tiny nodules. However, distinct from Fe-deficient nodules, higher iron concentration was accumulated and the Fe-S cluster biosynthesis genes were not suppressed in the P-deficiency-treated nodules. Taken together, our results showed that both Fe deficiency and P deficiency impair nodulation, but they affect the assembly of Fe-S cluster maybe via different mechanisms. The data also suggested that Fe-S cluster biosynthesis likely links Fe metabolism and P metabolism in root and nodule cells of soybean.

Iron Isotope Systematics

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

Dauphas, Nicolas; John, Seth G.; Rouxel, Olivier

Iron is a ubiquitous element with a rich (i.e., complex) chemical behavior. It possesses three oxidation states, metallic iron (Fe0), ferrous iron (Fe2+) and ferric iron (Fe3+). The distribution of these oxidation states is markedly stratified in the Earth.

Influence of FeEDDS, FeEDTA, FeDTPA, FeEDDHA, and FeSO4 on Marigold Growth and Nutrition, and Substrate and Runoff Chemistry

USDA-ARS?s Scientific Manuscript database

Objectives of the study were to determine effects of Fe source on plant growth, plant nutrition, substrate chemistry and runoff chemistry. Iron source (FS) treatments consisted of Fe-aminopolycarboxylic acid (APCA) complexones iron ethylenediaminetetraacetic acid (FeEDTA), iron [S, S']-ethylenediam...

Trace metal enrichment and organic matter sources in the surface sediments of Arabian Sea along southwest India (Kerala coast).

PubMed

Sreekanth, Athira; Mrudulrag, S K; Cheriyan, Eldhose; Sujatha, C H

2015-12-30

The geochemical distribution and enrichment of trace metals (Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn) were determined in the surface sediments of Arabian Sea, along southwest India, Kerala coast. The results of geochemical indices indicated that surficial sediments of five transects are uncontaminated with respect to Mn, Zn and Cu, uncontaminated to moderately contaminated with Co and Ni, and moderately to strongly contaminated with Pb. The deposition of trace elements exhibited three different patterns i) Cd and Zn enhanced with settling biodetritus from the upwelled waters, ii) Pb, Co and Ni show higher enrichment, evidenced by the association through adsorption of iron-manganese nodules onto clay minerals and iii) Cu enrichment observed close to major urban sectors, initiated by the precipitation as Cu sulfides. Correlation, principal component analysis (PCA) and cluster analysis (CA) were used to confirm the origin information of metals and the nature of organic matter composition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Elemental concentrations and bioaccessibilities in beached plastic foam litter, with particular reference to lead in polyurethane.

PubMed

Turner, Andrew; Lau, Kwan S

2016-11-15

Seventy samples of foamed plastic collected from a high-energy, sandy beach in SW England have been characterised by FTIR and XRF. Most samples were polyurethane (PU; n=39) or polystyrene (PS; n=27) that were associated with variable concentrations of Br-Cl, Fe and Zn, indicative of the presence of halogenated flame retardants, iron oxides and Zn-based additives, respectively. Many samples of rigid PU contained Pb, historically used as a catalyst, at concentrations of up to 16,000μgg -1 . A physiological extraction test that simulates the conditions in the gizzard of plastic-ingesting seabirds was applied to selected samples and results revealed that while Br and Zn were not measurably bioaccessible, Pb mobilisation progressed logarithmically over a period of time with maximum accessibilities after 220h of ~10% of total metal. Foamed PU is a source of bioaccessible Pb in the marine environment that has not previously been documented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Abundances in very metal-poor stars

NASA Astrophysics Data System (ADS)

Johnson, Jennifer Anne

We measured the abundances of 35 elements in 22 field red giants and a red giant in the globular cluster M92. We found the [Zn/Fe] ratio increases with decreasing [Fe/H], reaching ~0.3 at [Fe/H] = -3.0. While this is a larger [Zn/Fe] than found by previous investigators, it is not sufficient to account for the [Zn/Fe] observed in the damped Lyα systems. We test different models for the production of the s-process elements by comparing our [Y/Zr] values, which have been produced by the r- process, to predictions of what the s-process does not produce. We find that the models of Arlandini et al. (1999), which calculate s-process production in a model AGB star, agree the best. We then look at the r-process abundances across a wide range in mass. The [Y/Ba] values for most of our stars cluster around -0.30, but there are three outliers with [Y/Ba] values up to 1 dex higher. Thus the heavy element abundances do not show the same pattern from Z = 39 to Z = 56. However, our abundances ratios from Pd (Z = 46) to Yb (Z = 70) are consistent with a scaled solar system r- process pattern, arguing that at least the heavy r- process elements are made in a universal pattern. If we assume that this same pattern hold through thorium, we can determine the ages of our stars from the present abundance of radioactive thorium and an initial thorium abundance based on the abundance of stable heavy elements. Our results for five stars are consistent with those stars being the same age. Our mean age is 10.8 +/- 2 Gyr. However that result depends critically on the assumed Th/stable ratio, which we adopt from models of the r-process. For an average age of 15 Gyrs, the initial Th/Eu ratio we would need is 0.590. Finally, the [element/Fe] ratios for elements in the iron group and lower do not show any dispersion, unlike for the r- process elements such as Y and Ba. Therefore the individual contributions of supernovae have been erased for the lighter elements.

Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

PubMed

Mackie, Allison L; Walsh, Margaret E

2015-11-15

The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of CKD-HDS sludge. The results of this study suggest that solids loading is a significant factor in increased sludge density found with the HDS process compared to conventional lime precipitation-sedimentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Toxic metal(loid) speciation during weathering of iron sulfide mine tailings under semi-arid climate

PubMed Central

Root, Robert A.; Hayes, Sarah M.; Hammond, Corin M.; Maier, Raina M.; Chorover, Jon

2015-01-01

Toxic metalliferous mine-tailings pose a significant health risk to ecosystems and neighboring communities from wind and water dispersion of particulates containing high concentrations of toxic metal(loid)s (e.g., Pb, As, Zn). Tailings are particularly vulnerable to erosion before vegetative cover can be reestablished, i.e., decades or longer in semi-arid environments without intervention. Metal(loid) speciation, linked directly to bioaccessibility and lability, is controlled by mineral weathering and is a key consideration when assessing human and environmental health risks associated with mine sites. At the semi-arid Iron King Mine and Humboldt Smelter Superfund site in central Arizona, the mineral assemblage of the top 2 m of tailings has been previously characterized. A distinct redox gradient was observed in the top 0.5 m of the tailings and the mineral assemblage indicates progressive transformation of ferrous iron sulfides to ferrihydrite and gypsum, which, in turn weather to form schwertmannite and then jarosite accompanied by a progressive decrease in pH (7.3 to 2.3). Within the geochemical context of this reaction front, we examined enriched toxic metal(loid)s As, Pb, and Zn with surficial concentrations 41.1, 10.7, 39.3 mM kg-1 (3080, 2200, and 2570 mg kg-1), respectively. The highest bulk concentrations of As and Zn occur at the redox boundary representing a 1.7 and 4.2 fold enrichment relative to surficial concentrations, respectively, indicating the translocation of toxic elements from the gossan zone to either the underlying redox boundary or the surface crust. Metal speciation was also examined as a function of depth using X-ray absorption spectroscopy (XAS). The deepest sample (180 cm) contains sulfides (e.g., pyrite, arsenopyrite, galena, and sphalerite). Samples from the redox transition zone (25-54 cm) contain a mixture of sulfides, carbonates (siderite, ankerite, cerrusite, and smithsonite) and metal(loid)s sorbed to neoformed secondary Fe phases, principally ferrihydrite. In surface samples (0-35 cm), metal(loid)s are found as sorbed species or incorporated into secondary Fe hydroxysulfate phases, such as schwertmannite and jarosites. Metal-bearing efflorescent salts (e.g., ZnSO4·nH2O) were detected in the surficial sample. Taken together, these data suggest the bioaccessibility and lability of metal(loid)s are altered by mineral weathering, which results in both the downward migration of metal(loid)s to the redox boundary, as well as the precipitation of metal salts at the surface. PMID:26549929

Effect of metal cation ratio on chemical properties of ZnFe2O4/AC composite and adsorption of organic contaminant

NASA Astrophysics Data System (ADS)

Meilia, Demara; Misbah Khunur, Mochamad; Setianingsih, Tutik

2018-01-01

Porous woody char is biochar prepared through pyrolisis. The biochar can be used as adsorbent. In this research, ZnFe2O4/AC composite was synthesized through imregnation of the woody biochar with ZnFe2O4 to study effect of mol ratio of Fe(III) and Zn(II) toward their physicochemistry and adsorption of drug wastewater. Paracetamol was used as adsorbate model. This research was conducted in several steps, including activation of the woody biochar using KOH activator at temperatur 500 °C for 15 min to produce the activated carbon, fungsionalization of the carbon using H2SO4 oxidator (6M) at temperature of 80 °C for 3 h, impregnation of the oxidized activated carbon with Zn-Fe-LDH (Layered Double Hydroxide) at various mol ratio of Fe(III) and Zn(III), including 1:2, 1:3 and 1:4 using NaOH solution (5M) for coprecipitation, and calcination of Zn-Fe-LDH/AC at 950 °C for 5 min to produce ZnFe2O4/AC. FTIR diffraction characterization indicated existence of M-O (M = Zn(II), Fe(III)) and OH functional groups. FTIR spectra showed increasing of bands connected to -OH by increasing of the ratio till the ratio was achieved at 1:4, then decreased again. The ratio mol showed effect on the adsorption of paracetamol. Profile of adsorption value was fit with changing of functional groups. The highest adsorption was achieved at the ratio of 1:4. After calcination it gave the adsorption value of 17,66 mg/g.

Identification of an iron permease, cFTR1, in cyanobacteria involved in the iron reduction/re-oxidation uptake pathway.

PubMed

Xu, Ning; Qiu, Guo-Wei; Lou, Wen-Jing; Li, Zheng-Ke; Jiang, Hai-Bo; Price, Neil M; Qiu, Bao-Sheng

2016-12-01

Cyanobacteria are globally important primary producers and abundant in many iron-limited aquatic environments. The ways in which they take up iron are largely unknown, but reduction of Fe 3+ is an important step in the process. Here we report a special iron permease in Synechocystis, cFTR1, that is required for Fe 3+ uptake following Fe 2+ re-oxidation. The expression of cFTR1 is induced by iron starvation, and a mutant lacking the gene is abnormally sensitive to iron starvation. The cFTR1 protein localizes to the plasma membrane and contains the iron-binding motif "REXXE". Point-directed mutagenesis of the REXXE motif results in a sensitivity to Fe-deficiency. Measurements of iron ( 55 Fe) uptake rate show that cFTR1 takes up Fe 3+ rather than Fe 2+ . The function of cFTR1 in Synechocystis could be genetically complemented by the iron permease, Ftr1p, of Saccharomyces cerevisiae, that is known to transport Fe 3+ produced by the oxidation of Fe 2+ via a multicopper oxidase. Unlike yeast Ftr1p, cyanobacterial cFTR1 probably obtains Fe 3+ primarily from the oxidation of Fe 2+ by oxygen. Growth assays show that the cFTR1 is required during oxygenic, photoautotrophic growth but not when oxygen production is inhibited during photoheterotrophic growth. In cyanobacteria, iron reduction/re-oxidation uptake pathway may represent their adaptation to oxygenated environments. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Nitrogenase-mimic iron-containing chalcogels for photochemical reduction of dinitrogen to ammonia

DOE PAGES

Liu, Jian; Kelley, Matthew S.; Wu, Weiqiang; ...

2016-05-02

A nitrogenase-inspired biomimetic chalcogel system comprising double-cubane [Mo 2Fe 6S 8(SPh) 3] and single-cubane (Fe 4S 4) biomimetic clusters demonstrates photocatalytic N 2 fixation and conversion to NH 3 in ambient temperature and pressure conditions. Replacing the Fe 4S 4 clusters in this system with other inert ions such as Sb 3+, Sn 4+, Zn 2+ also gave chalcogels that were photocatalytically active. Finally, molybdenum-free chalcogels containing only Fe 4S 4 clusters are also capable of accomplishing the N2 fixation reaction with even higher efficiency than their Mo 2Fe 6S 8(SPh) 3-containing counterparts. In this study, our results suggest thatmore » redox-active iron-sulfide–containing materials can activate the N 2 molecule upon visible light excitation, which can be reduced all of the way to NH 3 using protons and sacrificial electrons in aqueous solution. Evidently, whereas the Mo 2Fe 6S 8(SPh) 3 is capable of N 2 fixation, Mo itself is not necessary to carry out this process. The initial binding of N 2 with chalcogels under illumination was observed with in situ diffuse-reflectance Fourier transform infrared spectroscopy (DRIFTS). 15N 2 isotope experiments confirm that the generated NH 3 derives from N 2. Density functional theory (DFT) electronic structure calculations suggest that the N 2 binding is thermodynamically favorable only with the highly reduced active clusters. Finally, the results reported herein contribute to ongoing efforts of mimicking nitrogenase in fixing nitrogen and point to a promising path in developing catalysts for the reduction of N 2 under ambient conditions.« less

Mechanisms and efficiency of the simultaneous removal of metals and cyanides by using ferrate(VI): crucial roles of nanocrystalline iron(III) oxyhydroxides and metal carbonates.

PubMed

Filip, Jan; Yngard, Ria A; Siskova, Karolina; Marusak, Zdenek; Ettler, Vojtech; Sajdl, Petr; Sharma, Virender K; Zboril, Radek

2011-08-29

The reaction of potassium ferrate(VI), K(2)FeO(4), with weak-acid dissociable cyanides--namely, K(2)[Zn(CN)(4)], K(2)[Cd(CN)(4)], K(2)[Ni(CN)(4)], and K(3)[Cu(CN)(4)]--results in the formation of iron(III) oxyhydroxide nanoparticles that differ in size, crystal structure, and surface area. During cyanide oxidation and the simultaneous reduction of iron(VI), zinc(II), copper(II), and cadmium(II), metallic ions are almost completely removed from solution due to their coprecipitation with the iron(III) oxyhydroxides including 2-line ferrihydrite, 7-line ferrihydrite, and/or goethite. Based on the results of XRD, Mössbauer and IR spectroscopies, as well as TEM, X-ray photoelectron emission spectroscopy, and Brunauer-Emmett-Teller measurements, we suggest three scavenging mechanisms for the removal of metals including their incorporation into the ferrihydrite crystal structure, the formation of a separate phase, and their adsorption onto the precipitate surface. Zn and Cu are preferentially and almost completely incorporated into the crystal structure of the iron(III) oxyhydroxides; the formation of the Cd-bearing, X-ray amorphous phase, together with Cd carbonate is the principal mechanism of Cd removal. Interestingly, Ni remains predominantly in solution due to the key role of nickel(II) carbonate, which exhibits a solubility product constant several orders of magnitude higher than the carbonates of the other metals. Traces of Ni, identified in the iron(III) precipitate, are exclusively adsorbed onto the large surface area of nanoparticles. We discuss the relationship between the crystal structure of iron(III) oxyhydroxides and the mechanism of metal removal, as well as the linear relationship observed between the rate constant and the surface area of precipitates. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

DOE PAGES

Lu, Yongwu; Yu, Fei; Hu, Jin; ...

2012-04-12

Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cumore » (111) was the active site for mixed alcohols synthesis, Fe 2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.« less

The effect of Fe2NiO4 and Fe4NiO4Zn magnetic nanoparticles on anaerobic digestion activity.

PubMed

Chen, Jian Lin; Steele, Terry W J; Stuckey, David C

2018-06-11

Two types of magnetic nanoparticles (MNPs), i.e. Ni ferrite nanoparticles (Fe 2 NiO 4 ) and Ni Zn ferrite nanoparticles (Fe 4 NiO 4 Zn) containing the trace metals Ni and Fe, were added to the anaerobic digestion of synthetic municipal wastewater at concentrations between 1 and 100 mg Ni L -1 in order to compare their effects on biogas (methane) production and sludge activity. Using the production of methane over time as a measure, the assays revealed that anaerobic digestion was stimulated by the addition of 100 mg Ni L -1 in Fe 2 NiO 4 NPs, while it was inhibited by the addition of 1-100 mg Ni L -1 in Fe 4 NiO 4 Zn NPs. Especially at 100 mg Ni L -1 , Fe 4 NiO 4 Zn NPs resulted in a total inhibition of anaerobic digestion. The metabolic activity of the anaerobic sludge was tested using the resazurin reduction assay, and the assay clearly revealed the negative effect of Fe 4 NiO 4 Zn NPs and the positive effect of Fe 2 NiO 4 NPs. Re-feeding fresh synthetic medium reactivated the NPs added to the anaerobic sludge, except for the experiment with 100 mg Ni L -1 addition of Fe 4 NiO 4 Zn NPs. The findings in this present study indicate a possible new strategy for NPs design to enhance anaerobic digestion. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Essential trace elements in milk and blood serum of lactating donkeys as affected by lactation stage and dietary supplementation with trace elements.

PubMed

Fantuz, F; Ferraro, S; Todini, L; Mariani, P; Piloni, R; Salimei, E

2013-11-01

The aim of this trial was to study the concentration of zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), selenium (Se), cobalt (Co) and iodine (I) in milk and blood serum of lactating donkeys, taking into account the effects of lactation stage and dietary supplementation with trace elements. During a 3-month period, 16 clinically healthy lactating donkeys (Martina-Franca-derived population), randomly divided into two homogeneous groups (control (CTL) and trace elements (TE)), were used to provide milk and blood samples at 2-week intervals. Donkeys in both groups had continuous access to meadow hay and were fed 2.5 kg of mixed feed daily, divided into two meals. The mixed feed for the TE group had the same ingredients as the CTL, but was supplemented with a commercial premix providing 163 mg Zn, 185 mg Fe, 36 mg Cu, 216 mg Mn, 0.67 mg Se, 2.78 mg Co and 3.20 mg I/kg mixed feed. The concentrations of Zn, Fe, Cu, Mn, Se, Co and I were measured in feeds, milk and blood serum by inductively coupled plasma-MS. Data were processed by ANOVA for repeated measures. The milk concentrations of all the investigated elements were not significantly affected by the dietary supplementation with TE. Serum concentrations of Zn, Fe, Cu Mn and Se were not affected by dietary treatment, but TE-supplemented donkeys showed significantly higher concentrations of serum Co (1.34 v. 0.69 μg/l) and I (24.42 v. 21.43 μg/l) than unsupplemented donkeys. The effect of lactation stage was significant for all the investigated elements in milk and blood serum, except for serum manganese. A clear negative trend during lactation was observed for milk Cu and Se concentrations (-38%), whereas that of Mn tended to increase. The serum Cu concentration was generally constant and that of Co tended to increase. If compared with data reported in the literature for human milk, donkey milk showed similarities for Zn, Mn, Co and I. Furthermore, this study indicated that, in the current experimental conditions, the mineral profile of donkey milk was not dependent on dietary TE supply.

Effect of Fe incorporation on the optical behavior of ZnO thin films prepared by sol-gel derived spin coating techniques

NASA Astrophysics Data System (ADS)

Rakkesh, R. Ajay; Malathi, R.; Balakumar, S.

2013-02-01

In this work, Fe doped Zinc Oxide (ZnO) thin films were fabricated on the glass substrate by sol-gel derived spin coating technique. X-ray Diffraction studies revealed that the obtained pure and Fe doped ZnO thin films were in the wurtzite and spinel phase respectively. The three well defined Raman lines at 432, 543 and 1091 cm-1 also confirmed the lattice structure of the ZnO thin film has wurtzite symmetry. While doping Fe atoms in the ZnO, there was a significant change in the phase from wurtzite to spinel structure; owing to Fe (III) ions being incorporated into the lattice through substitution of Zn (II) ions. Room temperature PL spectra showed that the role of defect mediated red emissions at 612 nm was due to radial recombination of a photogenerated hole with an electron that belongs to the Fe atoms, which were discussed in detail.