Solid-State Metalized Reduction of Magnesium-Rich Low-Nickel Oxide Ores Using Coal as the Reductant Based on Thermodynamic Analysis

NASA Astrophysics Data System (ADS)

Ma, Baozhong; Xing, Peng; Yang, Weijiao; Wang, Chengyan; Chen, Yongqiang; Wang, Hua

2017-08-01

The solid-state metalized reduction of magnesium-rich low-nickel oxide ore using coal as a reductant was studied based on thermodynamic analysis. The major constituent minerals of the ore were silicates and goethite. The former was the main nickel-bearing mineral, and the latter was the main iron-bearing mineral. Single factor tests were conducted to investigate the effects of reduction temperature, duration, and coal dosage on the beneficiation of nickel and iron such that optimal conditions were achieved. Considering the low recoveries of nickel and iron (Ni, 13.9 pct; Fe, 30.3 pct) under the obtained optimal conditions, an improved process, adding CaF2 before the reaction, was proposed to modify the solid-state metalized process. The results showed that the recoveries of nickel and iron reached to 96.5 and 73.4 pct, respectively, and that the grades of nickel and iron in the concentrate increased from 2.5 and 62.6 wt pct to 6.9 and 71.4 wt pct, respectively. Nickel and iron in the absence of CaF2 were metalized; nevertheless, the size of ferronickel particles was only 1 μm. Furthermore, alloys in the presence of CaF2 aggregated and exhibited bands with a length greater than 200 µm. These observations suggested that CaF2 could effectively reduce the surface tension of the newly generated alloy interface and promote the migration and polymerization of the alloy particles, which improves the beneficiation of nickel and iron by magnetic separation.

The effects of metamorphism on iron mineralogy and the iron speciation redox proxy

NASA Astrophysics Data System (ADS)

Slotznick, Sarah P.; Eiler, John M.; Fischer, Woodward W.

2018-03-01

As the most abundant transition metal in the Earth's crust, iron is a key player in the planetary redox budget. Observations of iron minerals in the sedimentary record have been used to describe atmospheric and aqueous redox environments over the evolution of our planet; the most common method applied is iron speciation, a geochemical sequential extraction method in which proportions of different iron minerals are compared to calibrations from modern sediments to determine water-column redox state. Less is known about how this proxy records information through post-depositional processes, including diagenesis and metamorphism. To get insight into this, we examined how the iron mineral groups/pools (silicates, oxides, sulfides, etc.) and paleoredox proxy interpretations can be affected by known metamorphic processes. Well-known metamorphic reactions occurring in sub-chlorite to kyanite rocks are able to move iron between different iron pools along a range of proxy vectors, potentially affecting paleoredox results. To quantify the effect strength of these reactions, we examined mineralogical and geochemical data from two classic localities where Silurian-Devonian shales, sandstones, and carbonates deposited in a marine sedimentary basin with oxygenated seawater (based on global and local biological constraints) have been regionally metamorphosed from lower-greenschist facies to granulite facies: Waits River and Gile Mountain Formations, Vermont, USA and the Waterville and Sangerville-Vassalboro Formations, Maine, USA. Plotting iron speciation ratios determined for samples from these localities revealed apparent paleoredox conditions of the depositional water column spanning the entire range from oxic to ferruginous (anoxic) to euxinic (anoxic and sulfidic). Pyrrhotite formation in samples highlighted problems within the proxy as iron pool assignment required assumptions about metamorphic reactions and pyrrhotite's identification depended on the extraction techniques utilized. The presence of diagenetic iron carbonates in many samples severely affected the proxy even at low grade, engendering an interpretation of ferruginous conditions in all lithologies, but particularly in carbonate-bearing rocks. Increasing metamorphic grades transformed iron in carbonates into iron in silicate minerals, which when combined with a slight increase in the amount of pyrrhotite, drove the proxy toward more oxic and more euxinic conditions. Broad-classes of metamorphic reactions (e.g. decarbonation, silicate formation) occurred at distinct temperatures-pressures in carbonates versus siliciclastics, and could be either abrupt between metamorphic facies or more gradual in nature. Notably, these analyses highlighted the importance of trace iron in phases like calcite, which otherwise might not be included in iron-focused research i.e. ore-system petrogenesis, metamorphic evolution, or normative calculations of mineral abundance. The observations show that iron is mobile and reactive during diagenesis and metamorphism, and these post-depositional processes can readily overprint primary redox information held by iron speciation. However, in principle, additional mineralogical and petrographic approaches can be combined with iron speciation data to help untangle many of these post-depositional processes and arrive at more accurate estimates of paleoenvironmental redox conditions and processes, even for metamorphosed samples.

Petrologic and geophysical study of the source of long wavelength crustal magnetic anomalies

NASA Technical Reports Server (NTRS)

Marsch, B.; Schlinger, C. M.

1983-01-01

The magnetic mineralogy and magnetic signature of banded ion formations, diagenetic (unmetamorphosed) and low grade banded iron formations, high-grade mineralogy, and phase equilibria of magnetite inorogenic magmers are discussed.

Dephosphorization of Levitated Silicon-Iron Droplets for Production of Solar-Grade Silicon

NASA Astrophysics Data System (ADS)

Le, Katherine; Yang, Yindong; Barati, Mansoor; McLean, Alexander

2018-05-01

The treatment of relatively inexpensive silicon-iron alloys is a potential refining route in order to generate solar-grade silicon. Phosphorus is one of the more difficult impurity elements to remove by conventional processing. In this study, electromagnetic levitation was used to investigate phosphorus behavior in silicon-iron alloy droplets exposed to H2-Ar gas mixtures under various experimental conditions including, refining time, temperature (1723 K to 1993 K), gas flow rate, iron content, and initial phosphorus concentration in the alloy. Thermodynamic modeling of the dephosphorization reaction permitted prediction of the various gaseous products and indicated that diatomic phosphorus is the dominant species formed.

Resistance to High-Temperature Oxidation and Wear of Various Ferrous Alloys Used in Rolling Mills

NASA Astrophysics Data System (ADS)

Delaunois, Fabienne; Stanciu, Victor Ioan; Sinnaeve, Mario

2018-03-01

Various materials are commonly used to manufacture work rolls for hot rolling mills, such as ICDP (Indefinite Chill Double Pour) cast irons, high-chromium white cast irons, and high speed steels (HSS). Various chemical compositions and microstructures are studied in order to optimize the in-use behavior of those grades of rolls. In this paper, six grades of ferrous alloys (an ICDP cast iron; an ICDP cast iron enriched in vanadium, niobium, and molybdenum; a HSS; a graphitic HSS; a high-chromium white cast iron (Hi-Cr); and a niobium-molybdenum-doped high-chromium white cast iron) were investigated. High-temperature oxidation tests with gravimetric means at 575 °C in water vapor atmosphere and sliding wear tests were carried out. The oxidation kinetics was followed during oxidation test. The microstructure was observed by optical and scanning electron microscopies. The oxides formed on the surface of the samples were analyzed by XRD and EDS. The thickness of the oxide scales and the mass gain were measured after oxidation test. The results showed that the behavior of all the grades differed. The oxide scale of HSS and HSS-G grades was fine and their friction coefficient was low. The weight gain after oxidation test of HSS was high. Hi-Cr and M-Hi-Cr grades presented highly porous oxide layer and an important increase of the friction coefficient during wear test. ICDP and M-ICDP had intermediate behavior.

A New Technique for Preparation of High-Grade Titanium Slag from Titanomagnetite Concentrate by Reduction-Melting-Magnetic Separation Processing

NASA Astrophysics Data System (ADS)

Lv, Chao; Yang, Kun; Wen, Shu-ming; Bai, Shao-jun; Feng, Qi-cheng

2017-10-01

This paper proposes a new technique for preparation of high-grade titanium slag from Panzhihua vanadium titanomagnetite concentrate by reduction-melting-magnetic separation processing. Chemical analysis, x-ray diffraction, and scanning electron microscopy in conjunction with energy-dispersive spectroscopy were used to characterize the samples. The effective separation of iron and titanium slag could be realized by melting metallized pellets at 1550°C for 60 min with the addition of 1% CaO (basicity of 1.1) and 2% graphite powder. The small iron particles embedded in the slag could be removed by fine grinding and magnetic separation process. The grade of TiO2 in the obtained high-grade titanium slag reached 60.68% and the total recovery of TiO2 was 91.25%, which could be directly applied for producing titanium white by the sulfuric acid process. This technique provides an alternative method to use vanadium titanomagnetite concentrate of the Panzhihua area in China.

Iron addiction: a novel therapeutic target in ovarian cancer

DOE PAGES

Basuli, D.; Tesfay, L.; Deng, Z.; ...

2017-03-20

Ovarian cancer is a lethal malignancy that has not seen a major therapeutic advance in over 30 years. We demonstrate that ovarian cancer exhibits a targetable alteration in iron metabolism. Ferroportin (FPN), the iron efflux pump, is decreased, and transferrin receptor (TFR1), the iron importer, is increased in tumor tissue from patients with high grade but not low grade serous ovarian cancer. A similar profile of decreased FPN and increased TFR1 is observed in a genetic model of ovarian cancer tumor-initiating cells (TICs). The net result of these changes is an accumulation of excess intracellular iron and an augmented dependencemore » on iron for proliferation. A forced reduction in intracellular iron reduces the proliferation of ovarian cancer TICs in vitro, and inhibits both tumor growth and intraperitoneal dissemination of tumor cells in vivo. Some mechanistic studies demonstrate that iron increases metastatic spread by facilitating invasion through expression of matrix metalloproteases and synthesis of interleukin 6 (IL-6). Here, we show that the iron dependence of ovarian cancer TICs renders them exquisitely sensitive in vivo to agents that induce iron-dependent cell death (ferroptosis) as well as iron chelators, and thus creates a metabolic vulnerability that can be exploited therapeutically.« less

Iron addiction: a novel therapeutic target in ovarian cancer

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

Basuli, D.; Tesfay, L.; Deng, Z.

Ovarian cancer is a lethal malignancy that has not seen a major therapeutic advance in over 30 years. We demonstrate that ovarian cancer exhibits a targetable alteration in iron metabolism. Ferroportin (FPN), the iron efflux pump, is decreased, and transferrin receptor (TFR1), the iron importer, is increased in tumor tissue from patients with high grade but not low grade serous ovarian cancer. A similar profile of decreased FPN and increased TFR1 is observed in a genetic model of ovarian cancer tumor-initiating cells (TICs). The net result of these changes is an accumulation of excess intracellular iron and an augmented dependencemore » on iron for proliferation. A forced reduction in intracellular iron reduces the proliferation of ovarian cancer TICs in vitro, and inhibits both tumor growth and intraperitoneal dissemination of tumor cells in vivo. Some mechanistic studies demonstrate that iron increases metastatic spread by facilitating invasion through expression of matrix metalloproteases and synthesis of interleukin 6 (IL-6). Here, we show that the iron dependence of ovarian cancer TICs renders them exquisitely sensitive in vivo to agents that induce iron-dependent cell death (ferroptosis) as well as iron chelators, and thus creates a metabolic vulnerability that can be exploited therapeutically.« less

Single-step laser deposition of functionally graded coating by dual ‘wire powder’ or ‘powder powder’ feeding—A comparative study

NASA Astrophysics Data System (ADS)

Syed, Waheed Ul Haq; Pinkerton, Andrew J.; Liu, Zhu; Li, Lin

2007-07-01

The creation of iron-copper (Fe-Cu) alloys has practical application in improving the surface heat conduction and corrosion resistance of, for example, conformal cooling channels in steel moulds, but is difficult to achieve because the elements have got low inter-solubility and are prone to solidification cracking. Previous work by these authors has reported a method to produce a graded iron-nickel-copper coating in a single-step by direct diode laser deposition (DLD) of nickel wire and copper powder as a combined feedstock. This work investigates whether dual powder feeds can be used in that process to afford greater geometric flexibility and compares attributes of the 'nickel wire and copper powder' and 'nickel powder and copper powder' processes for deposition on a H13 tool steel substrate. In wire-powder deposition, a higher temperature developed in the melt pool causing a clad with a smooth gradient structure. The nickel powder in powder-powder deposition did not impart much heat into the melt pool so the melt pool solidified with sharp composition boundaries due to single metal melting in some parts. In wire-powder experiments, a graded structure was obtained by varying the flow rates of wire and powder. However, a graded structure was not realised in powder-powder experiments by varying either the feed or the directions. Reasons for the differences and flow patterns in the melt pools and their effect on final part properties of parts produced are discussed.

Progress in development of coated indexable cemented carbide inserts for machining of iron based work piece materials

NASA Astrophysics Data System (ADS)

Czettl, C.; Pohler, M.

2016-03-01

Increasing demands on material properties of iron based work piece materials, e.g. for the turbine industry, complicate the machining process and reduce the lifetime of the cutting tools. Therefore, improved tool solutions, adapted to the requirements of the desired application have to be developed. Especially, the interplay of macro- and micro geometry, substrate material, coating and post treatment processes is crucial for the durability of modern high performance tool solutions. Improved and novel analytical methods allow a detailed understanding of material properties responsible for the wear behaviour of the tools. Those support the knowledge based development of tailored cutting materials for selected applications. One important factor for such a solution is the proper choice of coating material, which can be synthesized by physical or chemical vapor deposition techniques. Within this work an overview of state-of-the-art coated carbide grades is presented and application examples are shown to demonstrate their high efficiency. Machining processes for a material range from cast iron, low carbon steels to high alloyed steels are covered.

Cardiac iron deposition in idiopathic hemochromatosis: histologic and analytic assessment of 14 hearts from autopsy.

PubMed

Olson, L J; Edwards, W D; McCall, J T; Ilstrup, D M; Gersh, B J

1987-12-01

In each heart taken from autopsies of 14 men with idiopathic hemochromatosis, the conduction system, atria and 10 sites in the ventricles were histologically graded for stainable iron. Stainable iron was exclusively sarcoplasmic; none was observed in the interstitium. The histologic grade for the same anatomic site varied among hearts and among different anatomic sites in the same heart. Ten hearts had stainable iron in all ventricular sites; one of the three hearts from patients who had undergone therapeutic phlebotomy had no iron at any site. Seven hearts had iron in the atria but at a lesser grade than that found in the ventricles; six hearts had mild focal iron deposition in the atrioventricular conduction system. None of the 14 hearts had stainable iron in the sinus node. Elemental iron was quantitated by atomic absorption spectroscopy in ventricular specimens contiguous to those studied histologically and also in age-matched control hearts. Elemental iron content was markedly increased in hearts with idiopathic hemochromatosis compared with control hearts (p less than 0.01). The quantity of elemental iron varied greatly, similar to stainable iron, but was highest subepicardially. Among the hearts from the 11 patients without prior phlebotomy, three had no stainable iron in the right ventricular septal subendocardium, suggesting that sampling error may be a problem in the evaluation of hemochromatosis by endomyocardial biopsy. The sarcoplasmic location of the iron indicates that cardiac involvement in idiopathic hemochromatosis represents a storage disease and not an infiltrative process; this finding is consistent with the normal ventricular wall thicknesses observed.

The time dependent magnetization of fine-grained iron in lunar breccias

NASA Technical Reports Server (NTRS)

Gose, W. A.; Carnes, J. G.

1973-01-01

Lunar breccias of low metamorphic grade offer a unique opportunity to investigate the magnetic properties of dispersed fine-grained iron. These rocks exhibit a pronounced time-dependent magnetization whose acquisition and decay are well explained by Neel's single-domain theory. The effect is due to iron grains in the range from 120 to 150 A in diameter, which covers the transition from superparamagnetic to stable single-domain behavior.

Reducing acid leaching of manganiferous ore: effect of the iron removal operation on solid waste disposal.

PubMed

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca; Vegliò, Francesco

2009-01-01

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.

Materials processing threshold report: 2. Use of low gravity for cast iron process development

NASA Technical Reports Server (NTRS)

Frankhouser, W. L.

1980-01-01

Potential applications of a low gravity environment of interest to the commercial producers of cast iron were assessed to determine whether low gravity conditions offer potential opportunities to producers for improving cast iron properties and expanding the use of cast irons. The assessment is limited to the gray and nodular types of iron, however, the findings are applicable to all cast irons. The potential advantages accrued through low gravity experiments with cast irons are described.

Manufacturing and Application of Metalized Ore-Coal Pellets in Synthetic Pig Iron Smelting

NASA Astrophysics Data System (ADS)

Nokhrina, O. I.; Rozhikhina, I. D.; Khodosov, I. E.

2016-08-01

The article presents research data on manufacturing and application of metalized ore-coal pellets in synthetic pig iron smelting. A technology of pellets metallization by means of solid-phase reduction of iron from oxides using hematite-magnetite iron ore and low-caking coal as raw materials is described. Industrial testing of replacing 10, 15, and 20% of waste metal by the metalized ore-coal pellets in the coreless induction furnace IST-1 is described. Optimal temperature and time conditions of feeding the metalized pellets into the furnace in smelting pig iron of SCh-40-60 grade are determined.

[Simple method for precognition of drug interaction between oral iron and phenolic hydroxyl group-containing drugs].

PubMed

Sunagane, Nobuyoshi; Yoshinobu, Etsuko; Murayama, Nobuko; Terawaki, Yasufumi; Kamimura, Naoki; Uruno, Tsutomu

2005-02-01

In the present study, we devised a simple method for detecting the drug interaction between oral iron preparations and phenolic hydroxyl group-containing drugs, using the coloring reaction as indicator, due to the formation of complexes or chelates. In the method, oral iron preparations and test drugs in amounts as much as single dose for adults were added to 10 ml of purified water to make sample suspensions for testing. Thirty minutes after mixing an oral iron suspension and a test drug suspension, the change of color in the mixture was observed macroscopically and graded as 0 to 3, with a marked color change judged as grade 3 and no color change as grade 0. Screening of 14 test drugs commonly used orally was carried out. When using sodium ferrous citrate preparations as oral iron, 5 were classified as grade 3, 2 as grade 2, 4 as grade 1, and 3 as grade 0, respectively. To verify usefulness of the method, the interactions suggested by screening were pharmacokinetically assessed by measuring serum concentrations of the drug in mice. When a levodopa or droxidopa preparation, judged as grade 3 in screening, was concomitantly administered with an iron preparation, a significant reduction in bioavailability of the test drug was observed, indicating possible drug interaction between the test drug and oral iron. Combined administration of an acetaminophen preparation, judged as grade 1, and oral iron preparation showed no influence on the bioavailability of the test drug, implying no detectable interactions between them. In conclusion, the simple method devised in the present study is useful for precognition of drug interactions between oral iron preparations and phenolic hydroxyl group-containing drugs, and the drugs with a higher grade in screening may induce drug interactions with oral iron.

Development of low-cost technology for the removal of iron and manganese from ground water in siwa oasis.

PubMed

El-Naggar, Hesham M

2010-01-01

Ground water is the only water resource for Siwa Oasis. It is obtained from natural freshwater wells and springs fed by the Nubian aquifer. Water samples collected from Siwa Oasis had relatively higher iron (Fe) and manganese (Mn) than the permissible limits specified in WHO Guidelines and Egyptian Standards for drinking water quality. Aeration followed by sand filtration is the most commonly used method for the removal of iron from ground water. The study aimed at development of low-cost technology for the removal of iron and manganese from ground water in Siwa Oasis. The study was carried out on Laboratory-scale columns experiments sand filters with variable depths of 15, 30, 45, 60, 75, 90 cm and three graded types of sand were studied. The graded sand (E.S. =0.205 mm, U.C. =3.366, depth of sand = 60 cm and filtration rate = 1.44 m3/m2/hr) was the best type of filter media. Iron and manganese concentrations measured in ground water with aeration only, decreased with an average removal percentage of 16%, 13% respectively. Iron and manganese concentrations after filtration with aeration came down to 0.1123, 0.05 mg/L respectively in all cases from an initial concentration of 1.14, 0.34 mg/L respectively. Advantages of such treatment unit included simplicity, low cost design, and no need for chemical addition. In addition, the only maintenance required was periodic washing of the sand filter or replacement of the sand in order to maintain reasonable flow rate through the system.

Increased Hepatic Iron Content Predicts Poor Survival in Patients With Iron Overload Who Underwent Allogeneic Hematopoietic Stem Cell Transplantation.

PubMed

Sivgin, Serdar; Baldane, Suleyman; Deniz, Kemal; Zararsiz, Gokmen; Kaynar, Leylagul; Cetin, Mustafa; Unal, Ali; Eser, Bulent

2016-08-01

Iron overload results in increased infection, venous-oclusive disease and hepatic dysfunction in allogeneic hematopoietic stem cell transplant (alloHSCT) recipients. Liver is one of the most common sites of iron overload. A total of 50 alloHSCT recipients that underwent liver biopsy in Erciyes Stem Cell Transplantation Hospital, Erciyes University, between 2004 and 2011 were enrolled in the study. The liver biopsy specimens have been obtained from the archives of Erciyes University, Department of Pathology and stainned for iron content. The mean age was found 34 ± 11 years. For median overall survival (OS); 53 months (min-max: 41-65) in patients with grade 0, 55 months (min-max: 47-64) in patients with grade 1, in patients with grade 2 patients 25.4 months (11.5-39.4 ), grade 3 patients 29.3 months (min-max: 12.3-46.3) and grade 4 patients 2.6 months (min-max: 2.0-3.3). Overall survival was correlated with the degree of liver iron content and it was statistically significant in Kaplan-Meier analysis (P < .001). Disease-free survival was found (DFS); grade 0 patients 47.1 months (min-max: 32.0-62.0), grade 1 patients 36.9 months (min-max: 21.0-65.0), grade 2 patients 23.5 months (min-max: 12.0-59.0), grade 3 patients 27.4 months (min-max: 5.3-59.3) and grade 4 patients 2.6 months (min-max: 2.0-3.0). For DFS; it was negatively correlated with the degree of liver iron content nevertheless; it was not was statistically significant in Kaplan-Meier analysis (P = .093).Hepatic iron overload might be associated with poor survival in patients with transfusional iron overload that underwent alloHSCT. Hepatic iron content might be associated with poorer prognosis in patients with iron overload that underwent alloHSCT. Copyright © 2016 Elsevier Inc. All rights reserved.

China's emergence as the world's leading iron-ore-consuming country

USGS Publications Warehouse

Kirk, W.S.

2004-01-01

China has become the leading iron ore consuming nation, and, based on recent steel production capacity increases and plans for more, its consumption will almost certainly to continue to grow. China's iron ore industry, however, faces a number of problems. China's iron ore is low-grade, expensive to process, and its mines are being depleted. For many Chinese steelmakers, particularly in the coastal regions, the delivered cost of domestic iron ore, is more than the delivered cost of foreign ore. Thus China's iron ore imports are expected to increase. As China's growth continues, it will almost certainly surpass Japan to become the leading iron ore importing country as well. Without China's increasing appetite for iron ore, the world iron ore market would be flat or declining. China's recent imports largely offset the slump in demand in North America and Europe. China is regarded by the iron ore industry as the growth sector for the next decade. Although Chinese imports are expected to continue their rapid increase and imports in other Asian countries are expected to continue growing, there appears to be enough greenfield and expansion projects to meet future demand for iron ore worldwide. Present suppliers of iron ore, Australia, Brazil, India, and South Africa, will probably be the chief beneficiaries of China's increasing consumption of iron ore. How long China can continue its extraordinary growth is the primary issue for the future of the iron ore industry. Based on the number and size of planned blast furnaces it appears that China's growth could continue for several more years. ?? 2004 Taylor and Francis.

Linking leach chemistry and microbiology of low-grade copper ore bioleaching at different temperatures

NASA Astrophysics Data System (ADS)

Jia, Yan; Sun, He-yun; Tan, Qiao-yi; Gao, Hong-shan; Feng, Xing-liang; Ruan, Ren-man

2018-03-01

The effects of temperature on chalcocite/pyrite oxidation and the microbial population in the bioleaching columns of a low-grade chalcocite ore were investigated in this study. Raffinate from the industrial bioleaching heap was used as an irrigation solution for columns operated at 20, 30, 45, and 60°C. The dissolution of copper and iron were investigated during the bioleaching processes, and the microbial community was revealed by using a high-throughput sequencing method. The genera of Ferroplasma, Acidithiobacillus, Leptospirillum, Acidiplasma, and Sulfobacillus dominated the microbial community, and the column at a higher temperature favored the growth of moderate thermophiles. Even though microbial abundance and activity were highest at 30°C, the column at a higher temperature achieved a much higher Cu leaching efficiency and recovery, which suggested that the promotion of chemical oxidation by elevated temperature dominated the dissolution of Cu. The highest pyrite oxidation percentage was detected at 45°C. Higher temperature resulted in precipitation of jarosite in columns, especially at 60°C. The results gave implications to the optimization of heap bioleaching of secondary copper sulfide in both enhanced chalcocite leaching and acid/iron balance, from the perspective of leaching temperature and affected microbial community and activity.

Continuous Steelmaking Directly from Ore

NASA Astrophysics Data System (ADS)

Warner, Noel A.

2014-12-01

In-line continuous processing of high-grade hematite ore (crushed ore or fines) with a pure hydrogen reductant is assessed. An appraisal is made of the rate controlling mechanisms involved in the reduction of a pure layer of molten wustite being transported by floating on a molten carrier iron carbon-free medium at temperatures just in excess of the iron melting point. Published research clearly indicates that under these conditions the kinetics are principally controlled by molecular gaseous diffusion. Thus, the rate is essentially not influenced by total gas pressure above 1 atmosphere. Accordingly, on safety grounds it is recommended that high pressure should not be used for hydrogen steelmaking in the future, but the operation should be conducted close to atmospheric pressure with low pressure steam encapsulation of the plant items involved. Using hydrogen as the reductant means that sub-surface nucleation of CO bubbles cannot disrupt continuous processing. The operation is then no different to processing a normal liquid phase. The off-gases from the reduction zone of a melt circulation loop are super-clean and only contaminated with iron vapor. Accordingly, the best available technology becomes available for energy conservation without risk of non-fusible solids deposition. The net result is that the energy requirements are expected to be superior to other potential processes.

Raman Spectroscopic Characterisation of Australian Banded Iron Formation and Iron Ore

NASA Astrophysics Data System (ADS)

Wells, M. A.; Ramanaidou, E. R.

2012-04-01

In Australia and world-wide over the past 5-10 years, declining reserves of premium, high-grade (>64% Fe), low-P bearing iron ore, have seen iron ore producers increase their utilisation of lower Fe-grade, higher P/Al/Si ore. In Australia, the channel iron deposits (CID), bedded iron deposits (BID) and, more recently, BIF-derived magnetite iron deposits (MID) have seen increased usage driven mainly by the increased demand from Chinese steel mills (Ramanaidou and Wells, 2011). Efficient exploitation and processing of these lower-grade iron ores requires a detailed understanding of their iron oxide and gangue mineralogy and geochemistry. The common Fe-bearing minerals (e.g., hematite, magnetite, goethite and kenomagnetite) in these deposits, as well as gangue minerals such as quartz and carbonates, are all strongly Raman active (e.g., de Faria et al., 1997). Their distinct Raman spectra enable them to be easily detected and mapped in situ in either unprepared material or samples prepared as polished blocks. In this paper, using representative examples of Australian CID ore, martite-goethite bedded iron deposit (BID) ore and banded iron formation (BIF) examined as polished blocks, we present a range of Raman spectra of the key iron ore minerals, and discuss how Raman spectroscopy can be applied to characterising iron ore mineralogy. Raman imaging micrographs, obtained using a StreamLine Plus Raman imaging system, clearly identified the main Fe-oxide and gangue components in the CID, BID and BIF samples when compared to optical micrographs. Raman analysis enabled the unequivocal identification of diamond in the CID ore as a contaminant from the polishing paste used to prepare the sample, and confirmed the presence of hematite in the BID ore in the form of martite, which can be morphologically similar to magnetite and, thus, difficult to otherwise distinguish. Image analysis of Raman mineral maps could be used to quantify mineral abundance based on the number of 'pixels' identified for each phase normalised to the total number of 'pixels' for each area scanned. Shifts in the main phonon lines of goethite and hematite mapped in the CID samples examined were used to estimate the Al substitution in these phases (e.g., Ramanaidou et al. 1996) which were consistent with electron microprobe data. The Raman data demonstrated the Al-free nature of hematite (0.5 mol% Al) and showed that goethite in the CID cortex was more Al-rich (10 mol%) than goethite in the CID matrix (3 mol% Al). Shifts in the excitation bands of carbonate mapped in the BIF sample were well related to the Mg content of Fe-carbonate, based on the work of Rividi et al. (2010) and confirmed by in situ spot analysis using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). This data confirmed the first world-wide occurrence of a high Mg-bearing siderite (pistomesite) in BIF. Detailed, in situ characterisation of the iron oxide and gangue mineralogy of iron ore deposits as provided by Raman spectroscopy provides a step change to current characterisation methods. Understanding and defining their mineralogy and geochemistry is critical in developing strategies to best manage and process existing BID and CID ores, as well as the newly emerging MID ores.

Intensification of the Reverse Cationic Flotation of Hematite Ores with Optimization of Process and Hydrodynamic Parameters of Flotation Cell

NASA Astrophysics Data System (ADS)

Poperechnikova, O. Yu; Filippov, L. O.; Shumskaya, E. N.; Filippova, I. V.

2017-07-01

The demand of high grade iron ore concentrates is a major issue due to the depletion of rich iron-bearing ores and high competitiveness in the iron ore market. Iron ore production is forced out to upgrade flowsheets to decrease the silica content in the pelettes. Different types of ore have different mineral composition and texture-structural features which require different mineral processing methods and technologies. The paper presents a comparative study of the cationic and anionic flotation routes to process a fine-grain oxidized iron ore. The modified carboxymethyl cellulose was found as the most efficient depressant in reverse cationic flotation. The results of flotation optimization of hematite ores using matrix of second-order center rotatable uniform design allowed to define the collector concentration, impeller rotation speed and air flowrate as the main flotation parameters impacting on the iron ore concentrate quality and iron recovery in a laboratory flotation machine. These parameters have been selected as independent during the experiments.

Characterization and Beneficiation Studies of a Low Grade Bauxite Ore

NASA Astrophysics Data System (ADS)

Rao, D. S.; Das, B.

2014-10-01

A low grade bauxite sample of central India was thoroughly characterized with the help of stereomicroscope, reflected light microscope and electron microscope using QEMSCAN. A few hand picked samples were collected from different places of the mine and were subjected to geochemical characterization studies. The geochemical studies indicated that most of the samples contain high silica and low alumina, except a few which are high grade. Mineralogically the samples consist of bauxite (gibbsite and boehmite), ferruginous mineral phases (goethite and hematite), clay and silicate (quartz), and titanium bearing minerals like rutile and ilmenite. Majority of the gibbsite, boehmite and gibbsitic oolites contain clay, quartz and iron and titanium mineral phases within the sample as inclusions. The sample on an average contains 39.1 % Al2O3 and 12.3 % SiO2, and 20.08 % of Fe2O3. Beneficiation techniques like size classification, sorting, scrubbing, hydrocyclone and magnetic separation were employed to reduce the silica content suitable for Bayer process. The studies indicated that, 50 % by weight with 41 % Al2O3 containing less than 5 % SiO2 could be achieved. The finer sized sample after physical beneficiation still contains high silica due to complex mineralogical associations.

The F'derik-Zouerate iron district: Mesoarchean and Paleoproterozoic iron formation of the Tiris Complex, Islamic Republic of Mauritania

USGS Publications Warehouse

Taylor, Cliff D.; Finn, Carol A.; Anderson, Eric D.; Bradley, Dwight C.; Joud, Mohamed; Taleb Mohamed, Ahmed; Horton, John D.; Johnson, Craig A.; Bouabdellah, Mohammed; Slack, John F.

2016-01-01

High-grade hematitic iron ores (of HIF, containing 60-65 wt%Fe) have been mined in Mauritania since 1952 from Superior-type iron deposits of the F'derik-Zouerate district.  Depletion of the high-grade ores in recent years has resulted in new exploration projects focused on lower-grade magnetite ores occurring in Algoma-type banded iron formation (of BIF, containing ca. 35 wt% Fe).  Mauritania is the seventeenth largest iron producer in the world and currently has about 1.1 Gt of crude iron ore reserves. 

Phlebotomy improves histology in chronic hepatitis C males with mild iron overload

PubMed Central

Sartori, Massimo; Andorno, Silvano; Rossini, Angelo; Boldorini, Renzo; Bozzola, Cristina; Carmagnola, Stefania; Piano, Mario Del; Albano, Emanuele

2010-01-01

AIM: To investigate the usefulness of mild iron depletion and the factors predictive for histological improvement following phlebotomy in Caucasians with chronic hepatitis C (CHC). METHODS: We investigated 28 CHC Caucasians with persistently elevated serum aminotransferase levels and non responders to, or unsuitable for, antiviral therapy who underwent mild iron depletion (ferritin ≤ 70 ng/mL) by long-term phlebotomy. Histological improvement, as defined by at least one point reduction in the staging score or, in case of unchanged stage, as at least two points reduction in the grading score (Knodell), was evaluated in two subsequent liver biopsies (before and at the end of phlebotomy, 48 ± 16 mo apart). RESULTS: Phlebotomy showed an excellent safety profile. Histological improvement occurred in 12/28 phlebotomized patients. Only males responded to phlebotomy. At univariate logistic analysis alcohol intake (P = 0.034), high histological grading (P = 0.01) and high hepatic iron concentration (HIC) (P = 0.04) before treatment were associated with histological improvement. Multivariate logistic analysis showed that in males high HIC was the only predictor of histological improvement following phlebotomy (OR = 1.41, 95% CI: 1.03-1.94, P = 0.031). Accordingly, 12 out of 17 (70%) patients with HIC ≥ 20 μmol/g showed histological improvements at the second biopsy. CONCLUSION: Male CHC Caucasian non-responders to antiviral therapy with low-grade iron overload can benefit from mild iron depletion by long-term phlebotomy. PMID:20128028

Reducing acid leaching of manganiferous ore: Effect of the iron removal operation on solid waste disposal

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

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca

2009-01-15

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary ironmore » removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO{sub 3}, NaOH, and Na{sub 2}CO{sub 3}. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.« less

Magnetite deposits near Klukwan and Haines, southeastern Alaska

USGS Publications Warehouse

Robertson, Eugene C.

1956-01-01

Low-grade iron ore is found in magnetite-bearing pyroxenite bodies near Klukwan and Haines in Southeastern Alaska. An alluvial fan at Haines also contains magnetite-bearing rock of possible economic significance. The Haines-Klukwan area is underlain by rocks of Mesozoic Including epidote diorite, quartz diorite, and alaskite of the Coast Range batholith, metabasalt (recrystallized lava flows and pyroclastic rocks), and, in the southern part, interbedded slate and limestone. Layering and foliation, where perceptible, generally strike northwest and dip steeply northeast. The iron deposits are found at or near the contact between the metabasalt and epidote diorite; they appear to represent highly-altered lava flows that were metamorphosed during the emplacement of the batholith. Several billion tens of rock containing about 13 percent magnetic iron are included in the pyroxenite body at Klukwan. Sampling and dip-needle data suggest the presence there of two or three tabular aches in which the rock has an average magnetic iron content of 20 percent or more. Pyroxenite bodies outcropping in three areas near Haines apparently are lower in grade than the Klukwan deposit; lack of exposures prevented thorough sampling but reconnaissance traverses with a dip needle failed to reveal important zones of high-grade iron ore. An alluvial fan adjoining the pyroxenite body at Klukwan contains several hundred million tons of broken rock having a magneticiron content of about 10 percent.

Biocatalytic and chemical leaching of a low-grade nickel laterite ore

NASA Astrophysics Data System (ADS)

Ciftci, Hasan; Atik, Suleyman; Gurbuz, Fatma

2018-04-01

Nickel and cobalt recovery from a low-grade nickel laterite ore, supplied from Çaldağ deposit (Manisa, Turkey) were investigated by bio and chemical leaching processes. The fungus, Aspergillus niger was used for biocatalytic leaching experiments. The effects of parameters (solid ratio and sucrose concentration) on the biocatalytic leaching of the ore were initially tested in flasks to obtain the optimum conditions for the A. niger. Then chemical leaching was applied as a comparison to bioleaching, using organic acids (citric, oxalic, acetic and gluconic acids) as well as a mixture of acids. According the results, the maximum dissolution yield of nickel, cobalt and iron were detected respectively as 95.3%, 74.3% and 50.0% by biocatalytic processes which containing 25% (w/v) sucrose and 1% (w/v) solids. The increase in the solid ratio adversely influenced the biocatalytic activity of A. niger. Finally, further tests in reactors (v = 1 and 10 L) were performed using the optimum conditions from the flask tests. The difference in metals recovery between biocatalytic and chemical leaching was significantly important. Bioleaching produced higher Ni and Co extractions (34.3-75.6%) than chemical process.

The role of sedimentology, oceanography, and alteration on the δ56Fe value of the Sokoman Iron Formation, Labrador Trough, Canada

NASA Astrophysics Data System (ADS)

Raye, Urmidola; Pufahl, Peir K.; Kyser, T. Kurtis; Ricard, Estelle; Hiatt, Eric E.

2015-09-01

The Sokoman Formation is a ca. 100-m-thick succession of interbedded iron formation and fine-grained siliciclastics deposited at 1.88 Ga. Accumulation occurred on a dynamic paleoshelf where oxygen stratification, coastal upwelling of hydrothermally derived Fe and Si, microbial processes, tide and storm currents, diagenesis, and low-grade prehnite-pumpellyite metamorphism controlled lithofacies character and produced complex associations of multigenerational chert, hematite, magnetite, greenalite, stilpnomelane and Fe carbonate. Hematite-rich facies were deposited along suboxic segments of the coastline where photosynthetic oxygen oases impinged on the seafloor. Hematitic, cross-stratified grainstones were formed by winnowing and reworking of freshly precipitated Fe-(oxyhydr)oxide and opal-A by waves and currents into subaqueous dunes. Magnetite-rich facies contain varying proportions of greenalite and stilpnomelane and record deposition in anoxic middle shelf environments beneath an oxygen chemocline. Minor negative Ce anomalies in hematitic facies, but prominent positive Ce and Eu anomalies and high LREE/HREE ratios in magnetite-rich facies imply the existence of a weakly oxygenated surface ocean above anoxic bottom waters. The Fe isotopic composition of 31 whole rock (-0.46 ⩽ δ56Fe ⩽ 0.47‰) and 21 magnetite samples (-0.29 ⩽ δ56Fe ⩽ 0.22‰) from suboxic and anoxic lithofacies was controlled primarily by the physical oceanography of the paleoshelf. Despite low-grade metamorphism recorded by the δ18O values of paragenetically related quartz and magnetite, the Sokoman Formation preserves a robust primary Fe isotopic signal. Coastal upwelling is interpreted to have affected the isotopic equilibria between Fe2+aq and Fe-(oxyhydr)oxide in open marine versus coastal environments, which controlled the Fe isotopic composition of lithofacies. Unlike previous work that focuses on microbial and abiotic fractionation processes with little regard for paleoenvironment, our work demonstrates that depositional setting is paramount in governing the Fe isotopic composition of iron formations irrespective of what Fe-bearing minerals precipitated.

Improving titer while maintaining quality of final formulated drug substance via optimization of CHO cell culture conditions in low-iron chemically defined media.

PubMed

Xu, Jianlin; Rehmann, Matthew S; Xu, Xuankuo; Huang, Chao; Tian, Jun; Qian, Nan-Xin; Li, Zheng Jian

2018-04-01

During biopharmaceutical process development, it is important to improve titer to reduce drug manufacturing costs and to deliver comparable quality attributes of therapeutic proteins, which helps to ensure patient safety and efficacy. We previously reported that relative high-iron concentrations in media increased titer, but caused unacceptable coloration of a fusion protein during early-phase process development. Ultimately, the fusion protein with acceptable color was manufactured using low-iron media, but the titer decreased significantly in the low-iron process. Here, long-term passaging in low-iron media is shown to significantly improve titer while maintaining acceptable coloration during late-phase process development. However, the long-term passaging also caused a change in the protein charge variant profile by significantly increasing basic variants. Thus, we systematically studied the effect of media components, seed culture conditions, and downstream processing on productivity and quality attributes. We found that removing β-glycerol phosphate (BGP) from basal media reduced basic variants without affecting titer. Our goals for late-phase process development, improving titer and matching quality attributes to the early-phase process, were thus achieved by prolonging seed culture age and removing BGP. This process was also successfully scaled up in 500-L bioreactors. In addition, we demonstrated that higher concentrations of reactive oxygen species were present in the high-iron Chinese hamster ovary cell cultures compared to that in the low-iron cultures, suggesting a possible mechanism for the drug substance coloration caused by high-iron media. Finally, hypotheses for the mechanisms of titer improvement by both high-iron and long-term culture are discussed.

Sulfur-oxidizing bacteria dominate the microbial diversity shift during the pyrite and low-grade pyrolusite bioleaching process.

PubMed

Han, Yifan; Ma, Xiaomei; Zhao, Wei; Chang, Yunkang; Zhang, Xiaoxia; Wang, Xingbiao; Wang, Jingjing; Huang, Zhiyong

2013-10-01

The microbial ecology of the pyrite-pyrolusite bioleaching system and its interaction with ore has not been well-described. A 16S rRNA gene clone library was created to evaluate changes in the microbial community at different stages of the pyrite-pyrolusite bioleaching process in a shaken flask. The results revealed that the bacterial community was disturbed after 5 days of the reaction. Phylogenetic analysis of 16S rRNA sequences demonstrated that the predominant microorganisms were members of a genus of sulfur-oxidizing bacteria, Thiomonas sp., that subsequently remained dominant during the bioleaching process. Compared with iron-oxidizing bacteria, sulfur-oxidizing bacteria were more favorable to the pyrite-pyrolusite bioleaching system. Decreased pH due to microbial acid production was an important condition for bioleaching efficiency. Iron-oxidizing bacteria competed for pyrite reduction power with Mn(IV) in pyrolusite under specific conditions. These results extend our knowledge of microbial dynamics during pyrite-pyrolusite bioleaching, which is a key issue to improve commercial applications. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, V.A.; von Winbush, S.

1987-05-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500/degree/C, electrolysis at a voltage not more negative that about /minus/1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Molten salt extraction process for the recovery of valued transition metals from land-based and deep-sea minerals

DOEpatents

Maroni, Victor A.; von Winbush, Samuel

1988-01-01

A process for extracting transition metals and particularly cobalt and manganese together with iron, copper and nickel from low grade ores (including ocean-floor nodules) by converting the metal oxides or other compositions to chlorides in a molten salt, and subsequently using a combination of selective distillation at temperatures below about 500.degree. C., electrolysis at a voltage not more negative than about -1.5 volt versus Ag/AgCl, and precipitation to separate the desired manganese and cobalt salts from other metals and provide cobalt and manganese in metallic forms or compositions from which these metals may be more easily recovered.

Combined Iron Deficiency and Low Aerobic Fitness Doubly Burden Academic Performance among Women Attending University.

PubMed

Scott, Samuel P; De Souza, Mary Jane; Koehler, Karsten; Murray-Kolb, Laura E

2017-01-01

Academic success is a key determinant of future prospects for students. Cognitive functioning has been related to nutritional and physical factors. Here, we focus on iron status and aerobic fitness in young-adult female students given the high rate of iron deficiency and declines in fitness reported in this population. We sought to explore the combined effects of iron status and fitness on academic success and to determine whether these associations are mediated by cognitive performance. Women (n = 105) aged 18-35 y were recruited for this cross-sectional study. Data were obtained for iron biomarkers, peak oxygen uptake (VO 2peak ), grade point average (GPA), performance on computerized attention and memory tasks, and motivation and parental occupation. We compared the GPA of groups 1) with low compared with normal iron status, 2) among different fitness levels, and 3) by using a combined iron status and fitness designation. Mediation analysis was applied to determine whether iron status and VO 2peak influence GPA through attentional and mnemonic function. After controlling for age, parental occupation, and motivation, GPA was higher in women with normal compared with low ferritin (3.66 ± 0.06 compared with 3.39 ± 0.06; P = 0.01). In analyses of combined effects of iron status and fitness, GPA was higher in women with normal ferritin and higher fitness (3.70 ± 0.08) than in those with 1) low ferritin and lower fitness (3.36 ± 0.08; P = 0.02) and 2) low ferritin and higher fitness (3.44 ± 0.09; P = 0.04). Path analysis revealed that working memory mediated the association between VO 2peak and GPA. Low iron stores and low aerobic fitness may prevent female college students from achieving their full academic potential. Investigators should explore whether integrated lifestyle interventions targeting nutritional status and fitness can benefit cognitive function, academic success, and postgraduate prospects. © 2017 American Society for Nutrition.

Mineral resource of the month: vermiculite

USGS Publications Warehouse

Potter, M.J.

2008-01-01

Vermiculite, a hydrated magnesium-aluminum-iron silicate mineral, has a range of uses that take advantage of its fire resistance, good insulating properties, high liquid absorption capacity, inertness and low density. Most applications for vermiculite use an exfoliated (heat-expanded) form of the mineral. In general, coarser grades of vermiculite are used as loose fill insulation and in horticulture. Finer grades are used in wallboard and plasters and for animal feeds and fertilizers.

Recovery of iron from cyanide tailings with reduction roasting-water leaching followed by magnetic separation.

PubMed

Zhang, Yali; Li, Huaimei; Yu, Xianjin

2012-04-30

Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting-water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism. Copyright © 2012 Elsevier B.V. All rights reserved.

A Novel Approach to Evaluating the Iron and Folate Status of Women of Reproductive Age in Uzbekistan after 3 Years of Flour Fortification with Micronutrients

PubMed Central

Hund, Lauren; Northrop-Clewes, Christine A.; Nazario, Ronald; Suleymanova, Dilora; Mirzoyan, Lusine; Irisova, Munira; Pagano, Marcello; Valadez, Joseph J.

2013-01-01

Background The Uzbekistan 1996 Demographic Health Survey reported 60.4% of women of reproductive age (WRA) had low hemoglobin concentrations (<120 g/L), and anemia was an important public health problem. Fortification of wheat flour was identified as an appropriate intervention to address anemia due to the ubiquitous consumption of wheat flour. A National Flour Fortification Program (NFFP) was implemented in 2005. Methodology/Principal Findings After 3-years of the NFFP, a national survey using large country-lot quality assurance sampling was carried out to assess iron, folate, hemoglobin and inflammation status of WRA; the coverage and knowledge of the fortified first grade UzDonMakhsulot (UDM) flour/grey loaf program; and consumption habits of women to investigate the dietary factors associated with anemia. Estimated anemia prevalence was 34.4% (95% CI: 32.0, 36.7), iron depletion 47.5% (95% CI: 45.1, 49.9) and folate deficiency 28.8% (95% CI: 26.8, 30.8); the effect of inflammation was minimal (4% with CRP >5 mg/L). Severe anemia was more prevalent among folate deficient than iron depleted WRA. Presence of UDM first grade flour or the grey loaf was reported in 71.3% of households. Among WRA, 32.1% were aware of UDM fortification; only 3.7% mentioned the benefits of fortification and 12.5% understood causes of anemia. Consumption of heme iron-containing food (91%) and iron absorption enhancers (97%) was high, as was the consumption of iron absorption inhibitors (95%). Conclusions/Significance The NFFP coincided with a substantial decline in the prevalence of anemia. Folate deficiency was a stronger predictor of severe anemia than iron depletion. However, the prevalence of iron depletion was high, suggesting that women are not eating enough iron or iron absorption is inhibited. Fortified products were prevalent throughout Uzbekistan, though UDM flour must be adequately fortified and monitored in the future. Knowledge of fortification and anemia was low, suggesting consumer education should be prioritized. PMID:24260293

Determination of a Definition of Solar Grade Silicon

NASA Technical Reports Server (NTRS)

Hill, D. E.; Gutsche, H. W.

1975-01-01

A definition of solar grade silicon was determined by investigating the singular and the combined effect of the impurities usually found in metallurgical grade silicon on solar cell device performance. The impurity matrix was defined by Jet Propulsion Laboratory Technical Direction Memorandum. The initial work was focussed on standardizing the solar cell process and test procedure, growing baseline crystals, growing crystals contaminated with carbon, iron, nickel, zirconium, aluminum and vanadium, solar blank preparation, and material characterization.

Environmental Assessment Report. Saxon Harbor Operation and Maintenance Activities and Harbor Related Shoreline Erosion, Iron County, Wisconsin.

DTIC Science & Technology

1975-05-01

Extensive deposits of low-grade ore ( taconite ) remain in the county, and redevelopment of mining in Iron County is a possibility, utilizing modern technology...shale-derived sediments at the advent of the continental glaciation. The resistant sides of the trough (the present Minnesota shore, the Keweenaw...glacier retreated, a high terminal moraine associated with high ground on the Minnesota and Hichigan sides allowed a glacial lake to develop. The

Bioavailability of elemental iron powders to rats is less than bakery-grade ferrous sulfate and predicted by iron solubility and particle surface area.

PubMed

Swain, James H; Newman, Samuel M; Hunt, Janet R

2003-11-01

Foods are fortified with elemental forms of iron to reduce iron deficiency. However, the nutritional efficacy of current, commercially produced elemental iron powders has not been verified. We determined the bioavailability of six commercial elemental iron powders and examined how physicochemistry influences bioavailability. Relative biological value (RBV) of the iron powders was determined using a hemoglobin repletion/slope ratio method, treating iron-deficient rats with repletion diets fortified with graded quantities of iron powders, bakery-grade ferrous sulfate or no added iron. Iron powders were assessed physicochemically by measuring iron solubility in hydrochloric acid at pH 1.0 and 1.7, surface area by nitrogen gas adsorption and surface microstructure by electron microscopy. Bioavailability from the iron powders, based on absolute iron intake, was significantly less than from FeSO4 (100%; P < 0.05) with the following rank order: Carbonyl (64%; Ferronyl, U.S.) > Electrolytic (54%; A-131, U.S.) > Electrolytic (46%; Electrolytic Iron, India) > H-Reduced (42%; AC-325, U.S.) > Reduced (24%; ATOMET 95SP, Canada) > CO-Reduced (21%; RSI-325, Sweden). Solubility testing of the iron powders resulted in different relative rankings and better RBV predictability with increasing time at pH 1.7 (R2 = 0.65 at 150 min). The prediction was improved with less time and lower pH (R2 = 0.82, pH 1.0 at 30 min). Surface area, ranging from 90 to 370 m2/kg, was also highly predictive of RBV (R2 = 0.80). Bioavailability of iron powders is less than bakery-grade ferrous sulfate and varies up to three times among different commercial forms. Solubility at pH 1.0 and surface area were predictive of iron bioavailability in rats.

Hematology and biochemistry of aging-evidence of "anemia of the elderly" in old dogs.

PubMed

Radakovich, Lauren B; Pannone, Stephen C; Truelove, Matthew P; Olver, Christine S; Santangelo, Kelly S

2017-03-01

Effects of aging on hematologic and biochemical variables are well described in people. Anemia of the elderly is attributed to iron deficiency, anemia of chronic disease, chronic kidney disease, myelodysplasia, or idiopathic causes. Limited studies have examined these variables in aging dogs, but they have typically examined single breeds in research settings. The objective of this study was to identify differences in CBC and biochemistry values between adult and aged dogs of many breeds. Dogs presenting for wellness examinations and minor dental/elective surgeries that were otherwise clinically healthy were retrospectively identified. Dogs were categorized by age: adult (1-7.9 years), senior (8-11.9 years), and geriatric (12+ years). Standard CBC and biochemistry data were collated. Asian breeds, Greyhounds, and dogs with data indicating overt underlying disease were excluded. The Kruskal-Wallis test was used to compare groups with statistical significance set at P ≤ .05. Hematocrit, MCV, and serum iron decreased with age, indicating possible iron-restricted erythropoiesis (IRE), due to iron deficiency or low-grade chronic inflammation. Total proteins, globulins, and platelet counts increased with age while albumin decreased, suggesting low-grade inflammation. Urea was increased in older dogs without a concurrent increase in creatinine, which points toward gastrointestinal bleeding or dehydration. Clinically healthy, aging dogs have changes in laboratory variables that indicate altered physiologies compared to younger adult animals, including evidence of IRE, inflammation, and potential gastrointestinal bleeding, suggesting a similar trend to that of elderly human beings. Future studies will examine markers of iron metabolism and inflammation in aging dogs. © 2017 American Society for Veterinary Clinical Pathology.

Improvement in gold grade from iron-oxide mineral using reduction roasting and magnetic separation

NASA Astrophysics Data System (ADS)

Kim, Hyun-soo; On, Hyun-sung; Lim, Dae-hack; Myung, Eun-ji; Park, Cheon-young

2017-04-01

Microwave has a wide range of applications in mineral technology, metallurgy, etc. It is an established fact that microwave energy has potential for the speedy and efficient heating of minerals and in a commercial context may provide savings in both time and energy. Microwave heating is being developed as a potential thermal pre-treatment process, because of its unique advantages over the differences of ore minerals in absorbing microwaves. The aim of this study was to investigate the improvement in Au grade from iron-oxide mineral using reduction roasting and magnetic separation. The characteristics of iron-oxide mineral were analyzed using chemical, XRD and reflected light microscopy. The reduction roasting using microwave and magnetic separation experiments were examined under various conditions (reducing agent and chemical additive). The results of XRD and reflected light microscopy showed that the iron-oxide mineral mainly composed of illite, quartz and hematite. The iron-oxide mineral had an Au, Ag, Fe contents of 6.4, 35.1 and 155,441.1 mg/kg, respectively. The results demonstrated that the improvement in Au by reduction roasting using microwave (frequency of 2.45GHz, intensity of 5kW) and magnetic separation (magnetic field intensity of 9,000 Gauss) were effective processes. The Au content in iron-oxide mineral from 6.4 mg/kg to 14.2 mg/kg was achieved within microwave exposure time of 10min (reducing agent(PAC) ratio = 50 : 50, 5% of chemical additive(Soda ash)). Acknowledgment : This subject is supported by Korea Ministry of Environment as "Advanced Technology Program for Environmental Industry"

Mars Aqueous Processing System

NASA Technical Reports Server (NTRS)

Berggren, Mark; Wilson, Cherie; Carrera, Stacy; Rose, Heather; Muscatello, Anthony; Kilgore, James; Zubrin, Robert

2012-01-01

The goal of the Mars Aqueous Processing System (MAPS) is to establish a flexible process that generates multiple products that are useful for human habitation. Selectively extracting useful components into an aqueous solution, and then sequentially recovering individual constituents, can obtain a suite of refined or semi-refined products. Similarities in the bulk composition (although not necessarily of the mineralogy) of Martian and Lunar soils potentially make MAPS widely applicable. Similar process steps can be conducted on both Mars and Lunar soils while tailoring the reaction extents and recoveries to the specifics of each location. The MAPS closed-loop process selectively extracts, and then recovers, constituents from soils using acids and bases. The emphasis on Mars involves the production of useful materials such as iron, silica, alumina, magnesia, and concrete with recovery of oxygen as a byproduct. On the Moon, similar chemistry is applied with emphasis on oxygen production. This innovation has been demonstrated to produce high-grade materials, such as metallic iron, aluminum oxide, magnesium oxide, and calcium oxide, from lunar and Martian soil simulants. Most of the target products exhibited purities of 80 to 90 percent or more, allowing direct use for many potential applications. Up to one-fourth of the feed soil mass was converted to metal, metal oxide, and oxygen products. The soil residue contained elevated silica content, allowing for potential additional refining and extraction for recovery of materials needed for photovoltaic, semiconductor, and glass applications. A high-grade iron oxide concentrate derived from lunar soil simulant was used to produce a metallic iron component using a novel, combined hydrogen reduction/metal sintering technique. The part was subsequently machined and found to be structurally sound. The behavior of the lunar-simulant-derived iron product was very similar to that produced using the same methods on a Michigan iron ore concentrate, which demonstrates that lunar-derived material can be used in a manner similar to conventional terrestrial iron. Metallic iron was also produced from the Mars soil simulant. The aluminum and magnesium oxide products produced by MAPS from lunar and Mars soil simulants exhibited excellent thermal stability, and were shown to be capable of use for refractory oxide structural materials, or insulation at temperatures far in excess of what could be achieved using unrefined soils. These materials exhibited the refractory characteristics needed to support iron casting and forming operations, as well as other thermal processing needs. Extraction residue samples contained up to 79 percent silica. Such samples were successfully fused into a glass that exhibited high light transmittance.

CHARACTERIZATION OF FLAME-SYNTHESIZED FE, CO, OR MN-DOPED TITANIA NANOSTRUCTURED PARTICLES

EPA Science Inventory

The flame-synthesized catalysts have higher surface areas than commercial-grade titania and are composed of nanometer-sized primary particles with low internal porosity. Preliminary studies suggest that flame-synthesized iron-doped titania may be photoactivated in the visible lig...

Host and environmental factors affect pulmonary responses measured in bronchoalveolar lavage

EPA Science Inventory

Abstract Obesity is considered a chronic low-grade inflammatory state which may predispose individuals to lung disease. Measures of obesity can be associated with changes in adipokine levels, cytokine concentrations, and indices of iron homeostasis in the serum. To test for an...

URANIUM PRECIPITATION PROCESS

DOEpatents

Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

1957-12-01

A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

Innovative Method for Separating Phosphorus and Iron from High-Phosphorus Oolitic Hematite by Iron Nugget Process

NASA Astrophysics Data System (ADS)

Han, Hongliang; Duan, Dongping; Wang, Xing; Chen, Siming

2014-10-01

This study puts forward a new method to separate phosphorus and iron from high-phosphorus oolitic hematite through iron nuggets process. Firstly, the physical, chemical, and microscopic characteristics of high-phosphorus oolitic hematite are investigated. Then, the reaction mechanisms of high-phosphorus hematite together with feasibility to separating phosphorus and iron by iron nugget process are discussed. Meanwhile, the experiments of high-phosphorus hematite used in rotary hearth furnace iron nugget processes are studied as well. The results indicate that the iron nugget process is a feasible and efficient method for iron and phosphorus separation of high-phosphorus oolitic hematite. The phosphorus content in iron nuggets is relatively low. Through the optimization of process parameters, the lowest of phosphorus in iron nuggets is 0.22 pct, the dephosphorization rate is above 86 pct, and the recovery of Fe is above 85 pct by the iron nugget process. This study aims to provide a theoretical and technical basis for economical and rational use of high-phosphorus oolitic hematite.

Survey of metallurgical recycling processes. Final report

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

Pemsler, J.P.

1979-03-01

In the year 2000, the US will consume about 3.2 x 10/sup 15/ Btu to produce the seven major nonferrous metals Al, Cu, Zn, Pb, Ni, Mg, and Ti. Of this amount, 82% will be used in the production of Al. It is projected that 0.6 x 10/sup 15/ Btu will be saved by the recycle of secondary metals. Major opportunities for increasing the extent of recycle and thereby increasing the energy savings are discussed. An inherent feature in the energistics of recycle is that physical processes such as magnetic separation, density separations, melting, and in some instances vaporization aremore » far less energy intensive than are chemical processes associated with dissolution and electrowinning. It is in the domain of scrap of complex composition and physical form, difficult to handle by existing technology, that opportunities exist for new chemical recycle technology. Recycle of scrap metal of adequate grade is currently achieved through pyrometallurgical processes which, in many cases, are not very energy intensive as compared with hydrometallurgical processes. Preliminary flowsheets are presented for the recovery of value metals from batteries considered for use in vehicular propulsion and load leveling applications. The battery types examined are lead/acid, nickel/zinc, nickel/iron, zinc/chlorine, lithium-aluminum/iron sulfide, and sodium/sulfur. A flow sheet has been outlined for an integrated hydrometallurgical process to treat low-grade copper scrap. A fully integrated hydrometallurgical process is outlined, and costs and energy consumption are derived, for recovering zinc metal from electric furnace flue dusts. Costs and energy are high and the process does not appear to warrant development at this time. Improvement in the recycle of magnesium is associated primarily with improved recycle in the Al industry where Mg is an important alloy additive. Ni and Ti recycle are associated with improved collection and sorting of stainless steel and specialty alloys.« less

Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis.

PubMed

Yong, Seok; Park, Ji Chan; Lee, Ho-Tae; Yang, Jung-Il; Hong, SungJun; Jung, Heon; Chun, Dong Hyun

2016-02-01

Nanocrystalline iron ore particles were fabricated by a wet-milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet-milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good C5+ hydrocarbon productivity (about 0.22 g/g(cat)(-h)). This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS.

Direct Reduction of Iron Ore

NASA Astrophysics Data System (ADS)

Small, M.

1981-04-01

In the search for a pure, available iron source, steelmakers are focusing their attention on Directly Reduced Iron (DRI). This material is produced by the reaction of a low gangue iron ore with a hydrocarbonaceous substance. Commercially, DRI is generated in four different reactors: shaft (moving-bed), rotary kiln, fluidized bed, and retort (fixed-bed). Annual worldwide production capacity approaches 33 million metric tons. Detailed assessments have been made of the uses of DRI, especially as a substitute for scrap in electric furnace (EF) steelmaking. DRI is generally of a quality superior to current grades of scrap, with steels produced more efficiently in the EF and containing lower levels of impurities. However, present economics favor EF steel production with scrap. But this situation could change within this decade because of a developing scarcity of good quality scrap.

Iron and vegetarian diets.

PubMed

Saunders, Angela V; Craig, Winston J; Baines, Surinder K; Posen, Jennifer S

2013-08-19

Vegetarians who eat a varied and well balanced diet are not at any greater risk of iron deficiency anaemia than non-vegetarians. A diet rich in wholegrains, legumes, nuts, seeds, dried fruits, iron-fortified cereals and green leafy vegetables provides an adequate iron intake. Vitamin C and other organic acids enhance non-haem iron absorption, a process that is carefully regulated by the gut. People with low iron stores or higher physiological need for iron will tend to absorb more iron and excrete less. Research to date on iron absorption has not been designed to accurately measure absorption rates in typical Western vegetarians with low ferritin levels.

Dominance of sulfur-fueled iron oxide reduction in low-sulfate freshwater sediments.

PubMed

Hansel, Colleen M; Lentini, Chris J; Tang, Yuanzhi; Johnston, David T; Wankel, Scott D; Jardine, Philip M

2015-11-01

A central tenant in microbial biogeochemistry is that microbial metabolisms follow a predictable sequence of terminal electron acceptors based on the energetic yield for the reaction. It is thereby oftentimes assumed that microbial respiration of ferric iron outcompetes sulfate in all but high-sulfate systems, and thus sulfide has little influence on freshwater or terrestrial iron cycling. Observations of sulfate reduction in low-sulfate environments have been attributed to the presumed presence of highly crystalline iron oxides allowing sulfate reduction to be more energetically favored. Here we identified the iron-reducing processes under low-sulfate conditions within columns containing freshwater sediments amended with structurally diverse iron oxides and fermentation products that fuel anaerobic respiration. We show that despite low sulfate concentrations and regardless of iron oxide substrate (ferrihydrite, Al-ferrihydrite, goethite, hematite), sulfidization was a dominant pathway in iron reduction. This process was mediated by (re)cycling of sulfur upon reaction of sulfide and iron oxides to support continued sulfur-based respiration--a cryptic sulfur cycle involving generation and consumption of sulfur intermediates. Although canonical iron respiration was not observed in the sediments amended with the more crystalline iron oxides, iron respiration did become dominant in the presence of ferrihydrite once sulfate was consumed. Thus, despite more favorable energetics, ferrihydrite reduction did not precede sulfate reduction and instead an inverse redox zonation was observed. These findings indicate that sulfur (re)cycling is a dominant force in iron cycling even in low-sulfate systems and in a manner difficult to predict using the classical thermodynamic ladder.

Dominance of sulfur-fueled iron oxide reduction in low-sulfate freshwater sediments

PubMed Central

Hansel, Colleen M; Lentini, Chris J; Tang, Yuanzhi; Johnston, David T; Wankel, Scott D; Jardine, Philip M

2015-01-01

A central tenant in microbial biogeochemistry is that microbial metabolisms follow a predictable sequence of terminal electron acceptors based on the energetic yield for the reaction. It is thereby oftentimes assumed that microbial respiration of ferric iron outcompetes sulfate in all but high-sulfate systems, and thus sulfide has little influence on freshwater or terrestrial iron cycling. Observations of sulfate reduction in low-sulfate environments have been attributed to the presumed presence of highly crystalline iron oxides allowing sulfate reduction to be more energetically favored. Here we identified the iron-reducing processes under low-sulfate conditions within columns containing freshwater sediments amended with structurally diverse iron oxides and fermentation products that fuel anaerobic respiration. We show that despite low sulfate concentrations and regardless of iron oxide substrate (ferrihydrite, Al-ferrihydrite, goethite, hematite), sulfidization was a dominant pathway in iron reduction. This process was mediated by (re)cycling of sulfur upon reaction of sulfide and iron oxides to support continued sulfur-based respiration—a cryptic sulfur cycle involving generation and consumption of sulfur intermediates. Although canonical iron respiration was not observed in the sediments amended with the more crystalline iron oxides, iron respiration did become dominant in the presence of ferrihydrite once sulfate was consumed. Thus, despite more favorable energetics, ferrihydrite reduction did not precede sulfate reduction and instead an inverse redox zonation was observed. These findings indicate that sulfur (re)cycling is a dominant force in iron cycling even in low-sulfate systems and in a manner difficult to predict using the classical thermodynamic ladder. PMID:25871933

Emission coefficients of low temperature thermal iron plasma

NASA Astrophysics Data System (ADS)

Mościcki, T.; Hoffman, J.; Szymański, Z.

2004-03-01

Iron plasma appears during material processing with laser, electric are etc., and has considerable influence on the processing conditions. In this paper emission coefficients of low temperature thermal iron plasma at atmospheric pressure are presented. Net emission coefficients ɛ N have been calculated for pure iron plasma as well as for Fe-Ar and Fe-He plasma mixtures. To calculate the recombination radiation the knowledge of the Biberman factors ξ {fb/z}( T e, λ) is necessary and they have been calculated from the iron photo-ionization cross sections. The calculations allow estimation of energy losses, energy radiated by plasma plume and its comparison with the energy absorbed from laser beam.

Method of purifying metallurgical grade silicon employing reduced pressure atmospheric control

NASA Technical Reports Server (NTRS)

Ingle, W. M.; Thompson, S. W.; Chaney, R. E. (Inventor)

1979-01-01

A method in which a quartz tube is charged with chunks of metallurgical grade silicon and/or a mixture of such chunks and high purity quartz sand, and impurities from a class including aluminum, boron, as well as certain transition metals including nickel, iron, and manganese is described. The tube is then evacuated and heated to a temperature within a range of 800 C to 1400 C. A stream of gas comprising a reactant, such as silicon tetrafluoride, is continuously delivered at low pressures through the charge for causing a metathetical reaction of impurities of the silicon and the reactant to occur for forming a volatile halide and leaving a residue of silicon of an improved purity. The reactant which included carbon monoxide gas and impurities such as iron and nickel react to form volatile carbonyls.

Recovery of iron oxides from acid mine drainage and their application as adsorbent or catalyst.

PubMed

Flores, Rubia Gomes; Andersen, Silvia Layara Floriani; Maia, Leonardo Kenji Komay; José, Humberto Jorge; Moreira, Regina de Fatima Peralta Muniz

2012-11-30

Iron oxide particles recovered from acid mine drainage represent a potential low-cost feedstock to replace reagent-grade chemicals in the production of goethite, ferrihydrite or magnetite with relatively high purity. Also, the properties of iron oxides recovered from acid mine drainage mean that they can be exploited as catalysts and/or adsorbents to remove azo dyes from aqueous solutions. The main aim of this study was to recover iron oxides with relatively high purity from acid mine drainage to act as a catalyst in the oxidation of dye through a Fenton-like mechanism or as an adsorbent to remove dyes from an aqueous solution. Iron oxides (goethite) were recovered from acid mine drainage through a sequential precipitation method. Thermal treatment at temperatures higher than 300 °C produces hematite through a decrease in the BET area and an increase in the point of zero charge. In the absence of hydrogen peroxide, the solids adsorbed the textile dye Procion Red H-E7B according to the Langmuir model, and the maximum amount adsorbed decreased as the temperature of the thermal treatment increased. The decomposition kinetics of hydrogen peroxide is dependent on the H(2)O(2) concentration and iron oxides dosage, but the second-order rate constant normalized to the BET surface area is similar to that for different iron oxides tested in this and others studies. These results indicate that acid mine drainage could be used as a source material for the production of iron oxide catalysts/adsorbents, with comparable quality to those produced using analytical-grade reagents. Copyright © 2012 Elsevier Ltd. All rights reserved.

Feasibility Studies for Production of Pellet Grade Concentrate from Sub Grade Iron Ore Using Multi Gravity Separator

NASA Astrophysics Data System (ADS)

Rao, Gottumukkala Venkateswara; Markandeya, R.; Kumar, Rajan

2018-04-01

An attempt has been made to utilise Sub Grade Iron Ore by producing pellet grade concentrate from Deposit 5, Bacheli Complex, Bailadila, Chhattisgarh, India. The `as received' Run of Mine (ROM) sample assayed 40.80% Fe, 40.90% SiO2. Mineralogical studies indicated that the main ore mineral is Hematite and lone gangue mineral is Quartz. Mineral liberation studies indicated that, the ore mineral Hematite and gangue mineral Quartz are getting liberated below 100 microns. The stage crushed and ground sample was subjected to concentration by using a Multi Gravity Separator (MGS). Rougher Multi Gravity Separation (MGS) experimental results were optimised to recover highest possible iron values. A concentrate of 55.80% Fe with a yield of 61.73% by weight with a recovery of 84.42% Iron values was obtained in rougher MGS concentrate. Further experiments were carried out with rougher MGS concentrate to produce a concentrate suitable for commercial grade pellet concentrate. It was proved that a concentrate assaying 66.67% Fe, 3.12% SiO2 with an yield of 45.08% by weight and with a recovery of 73.67% iron values in the concentrate.

Combining Textural Techniques to Explore Effects of Diagenesis and Low-grade Metamorphism on Iron Mineralogy and Iron Speciation

NASA Astrophysics Data System (ADS)

Slotznick, S. P.; Webb, S.; Eiler, J. M.; Kirschvink, J. L.; Fischer, W. W.

2016-12-01

Iron chemistry and mineralogy in the sedimentary rocks provide a valuable tool for studying paleoenvironmental conditions due to the fact that iron atoms can take on either the +II or +III valence state under geological redox conditions. One method utilizing this redox chemistry is `iron speciation', a bulk chemical sequential extraction technique that maps proportions of iron species to redox conditions empirically calibrated from modern sediments. However, all Precambrian and many Phanerozoic rocks have experienced post-depositional processes; it is vital to explore their effects on iron mineralogy and speciation. We combined light and electron microscopy, magnetic microscopy, (synchrotron-based) microprobe x-ray spectroscopy, and rock magnetic measurements in order to deconvolve secondary overprints from primary phases and provide quantitative measurement of iron minerals. These techniques were applied to excellently-preserved shale and siltstone samples of the 1.4 Ga lower Belt Supergroup, Montana and Idaho, USA, spanning a metamorphic gradient from sub-biotite to garnet zone. Previously measured Silurian-Devonian shales, sandstones, and carbonates in Maine and Vermont, USA spanning from the chlorite to kyanite zone provided additional well-constrained, quantitative data for comparison and to extend our analysis. In all of the studied samples, pyrrhotite formation occurred at the sub-biotite or sub-chlorite zone. Pyrrhotite was interpreted to form from pyrite and/or other iron phases based on lithology; these reactions can affect the paleoredox proxy. Iron carbonates can also severely influence iron speciation results since they often form in anoxic pore fluids during diagenesis; textural analyses of the Belt Supergroup samples highlighted that iron-bearing carbonates were early diagenetic cements or later diagenetic overprints. The inclusion of iron from diagenetic minerals during iron speciation analyses will skew results by providing a view of pore-fluid redox, not ancient water column chemistry. While our analyses and biological indicators suggest that the studied samples of the lower Belt Supergroup and New England were deposited in oxic water columns, iron speciation results imply anoxic/ferruginous conditions due to diagenetic alterations affecting the record.

Evaluation of anemia diagnosis based on elastic light scattering (Conference Presentation)

NASA Astrophysics Data System (ADS)

Tong, Lieshu; Wang, Xinrui; Xie, Dengling; Chen, Xiaoya; Chu, Kaiqin; Dou, Hu; Smith, Zachary J.

2017-03-01

Currently, one-third of humanity is still suffering from anemia. In China the most common forms of anemia are iron deficiency and Thalassemia minor. Differentiating these two is the key to effective treatment. Iron deficiency is caused by malnutrition and can be cured by iron supplementation. Thalassemia is a hereditary disease in which the hemoglobin β chain is lowered or absent. Iron therapy is not effective, and there is evidence that iron therapy may be harmful to patients with Thalassemia. Both anemias can be diagnosed using red blood cell morphology: Iron deficiency presents a smaller mean cell volume compared to normal cells, but with a wide distribution; Thalassemia, meanwhile, presents a very small cell size and tight particle size distribution. Several researchers have proposed diagnostic indices based on red cell morphology to differentiate these two diseases. However, these indices lack sensitivity and specificity and are constructed without statistical rigor. Using multivariate methods we demonstrate a new classification method based on red cell morphology that diagnoses anemia in a Chinese population with enough accuracy for its use as a screening method. We further demonstrate a low cost instrument that precisely measures red cell morphology using elastic light scattering. This instrument is combined with an automated analysis program that processes scattering data to report red cell morphology without the need for user intervention. Despite using consumer-grade components, when comparing our experimental results with gold-standard measurements, the device can still achieve the high precision required for sensing clinically significant changes in red cell morphology.

A model for the biological precipitation of Precambrian iron-formation

NASA Technical Reports Server (NTRS)

Laberge, G. L.

1986-01-01

A biological model for the precipitation of Precambrian iron formations is presented. Assuming an oxygen deficient atmosphere and water column to allow sufficient Fe solubility, it is proposed that local oxidizing environments, produced biologically, led to precipitation of iron formations. It is further suggested that spheroidal structures about 30 mm in diameter, which are widespread in low grade cherty rion formations, are relict forms of the organic walled microfossil Eosphaera tylerii. The presence of these structures suggests that the organism may have had a siliceous test, which allowed sufficient rigidity for accumulation and preservation. The model involves precipitation of ferric hydrates by oxidation of iron in the photic zone by a variety of photosynthetic organisms. Silica may have formed in the frustules of silica secreting organisms, including Eosphaera tylerii. Iron formates formed, therefore, by a sediment rain of biologically produced ferric hydrates and silica and other organic material. Siderite and hematite formed diagenetically on basin floors, and subsequent metamorphism produced magnetite and iron silicates.

WILDERNESSES AND ROADLESS AREAS IN WHITE MOUNTAIN NATIONAL FOREST NEW HAMPSHIRE.

USGS Publications Warehouse

Moench, Robert H.; Gazdik, Gertrude C.

1984-01-01

On the basis of a mineral survey, a geologic terrane in north-central New Hampshire having an area of at least 300 sq mi has probable potential for the occurrence of tin resources. This terrane covers all of the Sandwich Range Roadless Area, approximately the eastern two thirds of the Pemigewasset Roadless Area, a large part of the Presidential Range-Dry River Wilderness, and the southern part of the Dry River Extension Roadless Area. If major tin deposits occur in New Hampshire, they are probably associated with the Mesozoic Conway Granite. Tin resources in the New Hampshire terrane may also occur in small but high-grade veins, as at the old Jackson tin mine; and in iron-beryllium deposits that are low grade with respect to tin but richer in iron, beryllium, lead, zinc, and silver, as at the old Iron Mountain mine. The resource potential for uranium, tungsten, and niobium in the same and other parts of the area investigated cannot be evaluated frpm present data. The nature of the geologic terrain indicates little likelihood of the occurrence of organic fuels.

Filamentous microbial fossil from low-grade metamorphosed basalt in northern Chichibu belt, central Shikoku, Japan

NASA Astrophysics Data System (ADS)

Sakakibara, M.; Sugawara, H.; Tsuji, T.; Ikehara, M.

2014-05-01

The past two decades have seen the reporting of microbial fossils within ancient oceanic basalts that could be identical to microbes within modern basalts. Here, we present new petrographic, mineralogical, and stable isotopic data for metabasalts containing filamentous structures in a Jurassic accretionary complex within the northern Chichibu Belt of the Yanadani area of central Shikoku, Japan. Mineralized filaments within these rocks are present in interstitial domains filled with calcite, pumpellyite, or quartz, and consist of iron oxide, phengite, and pumpellyite. δ13CPDB values for filament-bearing calcite within these metabasalts vary from -2.49‰ to 0.67‰. A biogenic origin for these filamentous structures is indicated by (1) the geological context of the Yanadani metabasalt, (2) the morphology of the filaments, (3) the carbon isotope composition of carbonates that host the filaments, and (4) the timing of formation of these filaments relative to the timing of low-grade metamorphism in a subduction zone. The putative microorganisms that formed these filaments thrived between eruption (Late Paleozoic) and accretion (Early Jurassic) of the basalt. The data presented here indicate that cryptoendolithic life was present within water-filled vesicles in pre-Jurassic intraplate basalts. The mineralogy of the filaments reflects the low-grade metamorphic recrystallization of authigenic microbial clays similar to those formed by the encrustation of prokaryotes in modern iron-rich environments. These findings suggest that a previously unusual niche for life is present within intraplate volcanic rocks in accretionary complexes.

The induction of two biosynthetic enzymes helps Escherichia coli sustain heme synthesis and activate catalase during hydrogen peroxide stress.

PubMed

Mancini, Stefano; Imlay, James A

2015-05-01

Hydrogen peroxide pervades many natural environments, including the phagosomes that mediate cell-based immunity. Transcriptomic analysis showed that during protracted low-grade H(2)O(2) stress, Escherichia coli responds by activating both the OxyR defensive regulon and the Fur iron-starvation response. OxyR induced synthesis of two members of the nine-step heme biosynthetic pathway: ferrochelatase (HemH) and an isozyme of coproporphyrinogen III oxidase (HemF). Mutations that blocked either adaptation caused the accumulation of porphyrin intermediates, inadequate activation of heme enzymes, low catalase activity, defective clearance of H(2)O(2) and a failure to grow. Genetic analysis indicated that HemH induction is needed to compensate for iron sequestration by the mini-ferritin Dps. Dps activity protects DNA and proteins by limiting Fenton chemistry, but it interferes with the ability of HemH to acquire the iron that it needs to complete heme synthesis. HemF is a manganoprotein that displaces HemN, an iron-sulfur enzyme whose synthesis and/or stability is apparently problematic during H(2)O(2) stress. Thus, the primary responses to H(2)O(2), including the sequestration of iron, require compensatory adjustments in the mechanisms of iron-cofactor synthesis. The results support the growing evidence that oxidative stress is primarily an iron pathology. © 2015 John Wiley & Sons Ltd.

Kinetic study of nickel laterite reduction roasting by palm kernel shell charcoal

NASA Astrophysics Data System (ADS)

Sugiarto, E.; Putera, A. D. P.; Petrus, H. T. B. M.

2017-05-01

Demand to process nickel-bearing laterite ore increase as continuous depletion of high-grade nickel-bearing sulfide ore takes place. Due to its common nickel association with iron, processing nickel laterite ore into nickel pig iron (NPI) has been developed by some industries. However, to achieve satisfying nickel recoveries, the process needs massive high-grade metallurgical coke consumption. Concerning on the sustainability of coke supply and positive carbon emission, reduction of nickel laterite ore using biomass-based reductor was being studied.In this study, saprolitic nickel laterite ore was being reduced by palm kernel shell charcoal at several temperatures (800-1000 °C). Variation of biomass-laterite composition was also conducted to study the reduction mechanism. X-ray diffraction and gravimetry analysis were applied to justify the phenomenon and predict kinetic model of the reduction. Results of this study provide information that palm kernel shell charcoal has similar reducing result compared with the conventional method. Reduction, however, was carried out by carbon monoxide rather than solid carbon. Regarding kinetics, Ginstling-Brouhnstein kinetic model provides satisfying results to predict the reduction phenomenon.

Effect of Groundwater Iron on Residual Chlorine in Water Treated with Sodium Dichloroisocyanurate Tablets in Rural Bangladesh

PubMed Central

Naser, Abu Mohd.; Higgins, Eilidh M.; Arman, Shaila; Ercumen, Ayse; Ashraf, Sania; Das, Kishor K.; Rahman, Mahbubur; Luby, Stephen P.; Unicomb, Leanne

2018-01-01

Abstract. We assessed the ability of sodium dichloroisocyanurate (NaDCC) to provide adequate chlorine residual when used to treat groundwater with variable iron concentration. We randomly selected 654 tube wells from nine subdistricts in central Bangladesh to measure groundwater iron concentration and corresponding residual-free chlorine after treating 10 L of groundwater with a 33-mg-NaDCC tablet. We assessed geographical variations of iron concentration using the Kruskal–Wallis test and examined the relationships between the iron concentrations and chlorine residual by quantile regression. We also assessed whether user-reported iron taste in water and staining of storage vessels can capture the presence of iron greater than 3 mg/L (the World Health Organization threshold). The median iron concentration among measured wells was 0.91 (interquartile range [IQR]: 0.36–2.01) mg/L and free residual chlorine was 1.3 (IQR: 0.6–1.7) mg/L. The groundwater iron content varied even within small geographical regions. The median free residual chlorine decreased by 0.29 mg/L (95% confidence interval: 0.27, 0.33, P < 0.001) for every 1 mg/L increase in iron concentration. Owner-reported iron staining of the storage vessel had a sensitivity of 92%, specificity of 75%, positive predictive value of 41%, and negative predictive value of 98% for detecting > 3 mg/L iron in water. Similar findings were observed for user-reported iron taste in water. Our findings reconfirm that chlorination of groundwater that contains iron may result in low-level or no residual. User reports of no iron taste or no staining of storage containers can be used to identify low-iron tube wells suitable for chlorination. Furthermore, research is needed to develop a color-graded visual scale for iron staining that corresponds to different iron concentrations in water. PMID:29436334

Effects of Aging on PuO2∙xH2O Particle Size in Alkaline Solution

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

Delegard, Calvin H.

Between 1944 and 1989, 54.5 metric tons of the United States’ weapons-grade plutonium and an additional 12.9 metric tons of fuel-grade plutonium were produced and separated from irradiated fuel at the Hanford Site. Acidic high-activity wastes containing around 600 kg of plutonium were made alkaline and discharged to underground storage tanks from separations, isolation, and recycle processes to yield average plutonium concentration of about 0.003 grams per liter (or ~0.0002 wt%) in the ~200 million liter tank waste volume. The plutonium is largely associated with low-solubility metal hydroxide/oxide sludges where its low concentration and intimate mixture with neutron-absorbing elements (e.g.,more » iron) are credited in nuclear criticality safety. However, concerns have been expressed that plutonium, in the form of plutonium hydrous oxide, PuO2∙xH2O, could undergo sufficient crystal growth through dissolution and reprecipitation in the alkaline tank waste to potentially become separable from neutron absorbing constituents by settling or sedimentation. Thermodynamic considerations and laboratory studies of systems chemically analogous to tank waste show that the plutonium formed in the alkaline tank waste by precipitation through neutralization from acid solution probably entered as 2–4-nm PuO2∙xH2O crystallite particles that, because of their low solubility and opposition from radiolytic processes, grow from that point at exceedingly slow rates, thus posing no risk of physical segregation.« less

Magnetic properties of Apollo 14 breccias and their correlation with metamorphism.

NASA Technical Reports Server (NTRS)

Gose, W. A.; Pearce, G. W.; Strangway, D. W.; Larson, E. E.

1972-01-01

The magnetic properties of Apollo 14 breccias can be explained in terms of the grain size distribution of the interstitial iron which is directly related to the metamorphic grade of the sample. In samples 14049 and 14313 iron grains less than 500 A in diameter are dominant as evidenced by a Richter-type magnetic aftereffect and hysteresis measurements. Both samples are of lowest metamorphic grade. The medium metamorphic-grade sample 14321 and the high-grade sample 14312 both show a logarithmic time-dependence of the magnetization indicative of a wide range of relaxation times and thus grain sizes, but sample 14321 contains a stable remanent magnetization whereas sample 14312 does not. This suggests that small multidomain particles (less than 1 micron) are most abundant in sample 14321 while sample 14312 is magnetically controlled by grains greater than 1 micron. The higher the metamorphic grade, the larger the grain size of the iron controlling the magnetic properties.

The association between red and processed meat consumption and iron intakes and status among British adults.

PubMed

Gibson, Sigrid; Ashwell, Margaret

2003-06-01

To examine the association between consumption of red and processed meat (RPM) and iron intakes and status in adults. Further analysis of the Dietary and Nutritional Survey of British Adults, a cross-sectional study of 2197 adults aged 16-64 years carried out in 1986/7. Adults (836 men and 838 women) with serum ferritin measurements, who were not taking iron supplements, were classified into four groups according to RPM consumption (from 7-day weighed records). Iron absorbed was estimated from equations based on haem and non-haem iron and the influence of iron stores. Women who ate least meat (<90 g day-1) had three times the risk of a low iron intake (below the Lower Reference Nutrient Intake) compared with high consumers of RPM (>140 g day-1). Men who ate no RPM also had a higher risk of low iron intake. Using an estimate of minimal values for iron losses, there was a twofold difference in the potential risk of negative iron balance between women non-RPM consumers and high RPM consumers. Status measurements indicated that, among women, anaemia was least prevalent (6%) among high consumers compared with 12-14% among average RPM consumers. Inverse trends were also observed for serum ferritin in both sexes. Low consumption of RPM has implications for iron intakes and iron status in men and women, since the risk of negative iron balance and its consequences are increased. Dietary messages must consider these implications and provide appropriate advice.

Evaluation of the mechanical properties of electroslag refined iron alloys

NASA Technical Reports Server (NTRS)

Bhat, G. K.

1976-01-01

Nitronic 40 (21Cr-6N-9Mn), HY-130, 9Ni-4Co, and D-6 alloys were prepared and evaluated in the form of 15.2 mm thick plates. Smooth bar tensile tests, double-edge sharp notch fracture toughness tests Charpy V-notch impact tests were conducted on appropriate heat treated specimens of the four steel plates at 22 C, -50 C, -100 C, -150 C, and -196 C. Similar material characterization, including metallographic evaluation studies on air melt and vacuum arc melt grades of same four alloy steels were conducted for comparative purposes. A cost analysis of manufacturing plates of air melt, electroslag remelt and vacuum arc remelt grades was performed. The results of both material characterization and cost analyses pointed out certain special benefits of electroslag processing iron base alloys.

Iron and copper release in drinking-water distribution systems.

PubMed

Shi, Baoyou; Taylor, James S

2007-09-01

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

Geological reconnaissance of some Uruguayan iron and manganese deposits in 1962

USGS Publications Warehouse

Wallace, Roberts Manning

1976-01-01

Three mineralized areas lie in an area near the town of Minas de Corrales in the Departamento de Rivera; they are the Cerro Amelia, the Cerro de Papagayo, and the Cerro Iman. The Cerro Amelia is composed of small bands of iron-rich rock separated by an amphibolitic or mafic rock. Selective mining would be necessary to extract the 31,000 tons per meter of depth of iron-rich rock that ranges from 15 to 40 percent metallic iron. The Cerro de Papagayo district contains many small, rich deposits of ferruginous manganese ore. The ratio of Mn to Fe varies widely within each small deposit as well as from deposit to deposit. Some ferruginous manganese ore contains 50-55 percent manganese dioxide. Although there are many thousands of tons of ore in the district, small-scale mining operations are imperative. One deposit, the Cerro Avestuz manganese mine, was visited. The manganese ore body lies within contorted highly metamorphosed itabirite that contains both hard low grade and soft high grade ferruginous manganese ores estimated to average 40 percent Mn. About 38,000 tons of manganese ore is present in this deposit. The Cerro Iman is a large block of itabirite that contains about 40 percent Fe. The grade is variable and probably runs from less than 35 percent Fe to more than 50 percent Fe. No exploration has been done on this deposit. It is recommended that the Cerro de Iman area be geologically mapped in detail, and that a geological reconnaissance be made of the area that is between the Cuchilla de Corrales and the Cuchilla de Areycua/Cuchilla del Cerro Pelado area.

The effect of Si-contents on the impact properties and dynamic graphite growth for cast iron QT400-18L

NASA Astrophysics Data System (ADS)

Lipeng, Jiang; Yingdong, Qu; Rongde, Li

2018-03-01

Low temperature impact test of QT400-18L ductile iron was investigated. The microstructure and fracture morphology were analyzed by the optical microscope and scanning electron microscope. The effect of different Si content on the graphite growth by liquid quenching method was discussed. There are the highest impact energies for the cast iron with 2.1% of Si over the whole investigated temperature range (‑60 to 20 °C). With the Si element addition increased from 1.9% to 2.1%, the graphite nodulizing grade of QT400 18L is increased from 5 to 7. However the graphite nodulizing grade is reduced from 7 to 6 with Si content increasing from 2.1% to 2.3%. When the Si element addition is exceed 2.1%, the excess of Si content also leads to abnormal graphite. The large size of the abnormal graphite is equivalent to a larger microcrack in the ferrite matrix, and it is helpful for the crack propagation. Large size of abnormal graphite not only destroyed the continuity of ferritic matrix, but also it creates the stress concentration in the surrounding.

Variation and inheritance of iron reductase activity in the roots of common vean (Phaseolus vulgaris L.) and association with seed iron accumulation QTL

USDA-ARS?s Scientific Manuscript database

Iron deficiency anemia is a global problem, which often affects women and children of developing countries and is based on diets that are low in iron. Strategy I plants, such as common bean (Phaseolus vulgaris L.) take up iron through a process that involves an iron reduction mechanism in their root...

Study on the pre-treatment of oxidized zinc ore prior to flotation

NASA Astrophysics Data System (ADS)

He, Dong-sheng; Chen, Yun; Xiang, Ping; Yu, Zheng-jun; Potgieter, J. H.

2018-02-01

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

Anemia of chronic disease is the more frequent type of anemia seen in patients with chronic idiopathic neutropenia of adults.

PubMed

Papadaki, H A; Eliopoulos, D G; Valatas, V; Eliopoulos, G D

2001-04-01

This study describes the frequency and the type of anemia seen in patients with nonimmune chronic idiopathic neutropenia of adults (NI-CINA). We found that NI-CINA patients had low hemoglobin levels and increased serum concentrations of erythropoietin (EPO), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta). The hemoglobin levels correlated positively with the number of circulating neutrophils and inversely with the levels of EPO and TNF-alpha but not of IL-1beta. Anemia, defined as the reduction of the hemoglobin below 12.0 g/dl for women and 13.3 g/dl for men, was found in 23 out of 148 patients studied, a proportion of 15.5%. Two of the anemic patients had iron deficiency anemia (8.7%), 11 had anemia of chronic disease (ACD; 47.8%) presenting with normal or slightly reduced erythrocytic indices, low serum iron, and increased serum ferritin, and the remaining ten had anemia of undefined pathogenesis (AUP; 43.5%) with normal or slightly decreased erythrocytic indices, serum iron ranging from 43 to 88 microg/dl, and ferritin values ranging from 12 to 50 ng/ml. We conclude that ACD is the more frequent type of anemia seen in patients with NI-CINA, and that pro-inflammatory cytokines, notably TNF-alpha, may be involved in the pathogenesis of both ACD and AUP, given that serum levels of the cytokine were significantly increased and that the EPO response to anemia was blunted in these patients. These findings further support our previously reported suggestion for the possible existence, in NI-CINA patients, of an unrecognized low-grade chronic inflammatory process that may be involved in the pathogenesis of the disorder.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

NASA Astrophysics Data System (ADS)

Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand, by plotting a binary diagram between chemical index of alteration (CIA) and other oxides while taking the samples of lower, middle and upper shales. It reflects an immobility and mobility of ions during partial and complete weathering processes (Mirza, 2011). Geochemical data indicate that BIF are in general detritus free chemical precipitates. Fe2O3 content of BHJ are varies in between 36.6% to 65.04%. In hard laminated ore, Fe2O3 content varies from 93.8% to 96.38%, Soft laminated ore varies from 83.64% to 89.5% and laterite ore varies from 53.5% to 79.11%. Fe2O3 content in Martite- Goethite ore varies from 86.38% to 89.42% and blue dust having 90.74% to 95.86% and all other oxides like SiO2, Al2O3, CaO, MgO, K2O, Na2O are decreases. Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The presence of intacalated tuffaceous shales pointing towards the genesis of iron, which could have leached from sea floor by volcanogenic process. Iron and silica of BIF were provided by the hydrothermal solutions emplaced at the vent sites situated at the Archean-Mid Oceanic Ridges. References: Mirza A (2011). Major element geochemistry of iron ore deposits in Noamundi-Koira basin of Singhbhum-Orissa craton (India). MSc thesis, Aligarh Muslim University, India. Saha AK (1994). Crustal evolution of Singhbhum, North Orissa, Eastern India; Geol. Soc. India Memoir 27 341. Sharma M, Basu AR and Ray SL (1994). Sm-Nd isotopic and geochemical study of the Archaean tonalite-amphibolite association from the eastern Indian craton. Contrib. Mineral Petrol. 117:45-55. Van Schalkwyk J and Beukes N J (1986). The Sishen iron ore deposit, Griqualand West; In: Mineral deposits of Southern Africa (eds) Annhaeusser C R and Maske S S, Geological Society of South Africa, Johannesburg, 931-956.

The Process of Nanostructuring of Metal (Iron) Matrix in Composite Materials for Directional Control of the Mechanical Properties

PubMed Central

Zemtsova, Elena

2014-01-01

We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1–50 nm. This material can be represented as the material type “frame in the frame” that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology. PMID:24695459

The process of nanostructuring of metal (iron) matrix in composite materials for directional control of the mechanical properties.

PubMed

Zemtsova, Elena; Yurchuk, Denis; Smirnov, Vladimir

2014-01-01

We justified theoretical and experimental bases of synthesis of new class of highly nanostructured composite nanomaterials based on metal matrix with titanium carbide nanowires as dispersed phase. A new combined method for obtaining of metal iron-based composite materials comprising the powder metallurgy processes and the surface design of the dispersed phase is considered. The following stages of material synthesis are investigated: (1) preparation of porous metal matrix; (2) surface structuring of the porous metal matrix by TiC nanowires; (3) pressing and sintering to give solid metal composite nanostructured materials based on iron with TiC nanostructures with size 1-50 nm. This material can be represented as the material type "frame in the frame" that represents iron metal frame reinforcing the frame of different chemical compositions based on TiC. Study of material functional properties showed that the mechanical properties of composite materials based on iron with TiC dispersed phase despite the presence of residual porosity are comparable to the properties of the best grades of steel containing expensive dopants and obtained by molding. This will solve the problem of developing a new generation of nanostructured metal (iron-based) materials with improved mechanical properties for the different areas of technology.

A green preparation of Mn-based product with high purity from low-grade rhodochrosite

NASA Astrophysics Data System (ADS)

Lian, F.; Ma, L.; Chenli, Z.; Mao, L.

2018-01-01

The low-grade rhodochrosite, the main resources for exploitation and applications in China, contains multiple elements such as iron, silicon, calcium and magnesium. So the conventional preparation of manganese sulphate and manganese oxide with high purity from electrolytic product is characterized by long production-cycle, high-resource input and high-pollution discharge. In our work, a sustainable preparation approach of high pure MnSO4 solution and Mn3O4 was studied by employing low-grade rhodochrosite (13.86%) as raw material. The repeated leaching of rhodochrosite with sulphuric acid was proposed in view of the same ion effect, in order to improve the solubility of Mn2+ and inhibit the dissolution of the impurities Ca2+ and Mg2+. With the aid of theoretical calculation, BaF2 was chosen to remove Ca2+ and Mg2+ completely in the process of purifying. The results showed that the impurities such as Ca2+, Mg2+, Na+ were decreased to less than 20ppm, and the Ni- and Fe- impurities were decreased to less than 1ppm, which meets the standards of high pure reagent for energy and electronic materials. The extraction ratio and the recovery ratio of manganese reached 94.3% and 92.7%, respectively. Moreover, the high pure Mn3O4 was one-step synthesized via the oxidation of MnSO4 solution with the ratios of OH-/Mn2+=2 and Mn2+/H2O2=1.03, and the recovery rate of manganese reaches 99%.

The Iron Metallome in Eukaryotic Organisms

PubMed Central

Dlouhy, Adrienne C.; Outten, Caryn E.

2013-01-01

This chapter is focused on the iron metallome in eukaryotes at the cellular and subcellular level, including properties, utilization in metalloproteins, trafficking, storage, and regulation of these processes. Studies in the model eukaryote Saccharomyces cerevisiae and mammalian cells will be highlighted. The discussion of iron properties will center on the speciation and localization of intracellular iron as well as the cellular and molecular mechanisms for coping with both low iron bioavailability and iron toxicity. The section on iron metalloproteins will emphasize heme, iron-sulfur cluster, and non-heme iron centers, particularly their cellular roles and mechanisms of assembly. The section on iron uptake, trafficking, and storage will compare methods used by yeast and mammalian cells to import iron, how this iron is brought into various organelles, and types of iron storage proteins. Regulation of these processes will be compared between yeast and mammalian cells at the transcriptional, post-transcriptional, and post-translational levels. PMID:23595675

High solubility pathway for the carbon dioxide free production of iron.

PubMed

Licht, Stuart; Wang, Baohui

2010-10-07

We report a fundamental change in the understanding of iron oxide thermochemistry, opening a facile, new CO(2)-free route to iron production. The resultant process can eliminate a major global source of greenhouse gas emission, producing the staple iron in molten media at high rate and low electrolysis energy.

Characterizing the adoption of low-grade hardwood lumber by the secondary wood processing industry

Treesearch

Robert L. Smith; Wibke Pohle; Philip Araman; Dan Cumbo

2004-01-01

This study investigated the adoption of low-grade lumber in the secondary hardwood industry. Factors influencing decisions regarding the utilization of low-grade lumber were identified and value-added opportunities to increase the use of low-grade lumber among manufacturers currently using higher grades were evaluated. Data were collected via a nationwide mail survey...

Water resources of the Marquette Iron Range area, Michigan

USGS Publications Warehouse

Wiitala, Sulo Werner; Newport, Thomas Gwyn; Skinner, Earl L.

1967-01-01

Large quantities of water are needed in the beneficiation and pelletizing processes by which the ore mined from low-grade iron-formations is upgraded into an excellent raw material for the iron and steel industry. Extensive reserves of low-grade iron-formation available for development herald an intensification of the demands upon the area's water supplies. This study was designed to provide water facts for public and private agencies in planning orderly development and in guiding the management of the water resources to meet existing and new requirements. Inland lakes and streams are the best potential sources of water for immediate development. The natural flow available for 90 percent of the time in the Middle and East Branches of the Escanaba River, the Carp River, and the Michigamme River is about 190 cubic feet per second. Potential storage sites are identified, and their complete development could increase the available supply from the above streams to about 450 cubic feet per second. Outwash deposits are the best potential sources of ground water. Large supplies could be developed from extensive outwash deposits in the eastern part of the area adjacent to Goose Lake Outlet and the East Branch Escanaba River. Other areas of outwash occur in the vicinity of Humboldt, West Branch Creek, and along the stream valleys. Streamflow data were used to make rough approximations of the ground-water potential in some areas. In general, however, the available data were not sufficient to permit quantitative evaluation of the potential ground-water supplies. Chemical quality of the surface and ground waters of the area is generally acceptable for most uses. Suspended sediment in the form of mineral tailings in effluents from ore-processing plants is a potential problem. Existing plants use settling basins to effectively remove most of the suspended material. Available records indicate that suspended-sediment concentrations and loads in the receiving waters have not been significantly increased by these operations. Present water use is about 60 cubic feet per second in the area. Thus, available water supplies are believed to be adequate for existing and foreseeable new uses. Water management, rather than water availability, is of prime consideration in this area. Time distribution of available water supplies, distribution of water to points of use, effect of surface-water development upon ground water and vice versa, and possible conflicts with competing uses are some of the management problems that are discussed. The presence of many inland lakes, favorable storage sites on streams, and several promising acquifers provide flexibility in possible water-management operations. A discussion of the interrelationships between surface and ground water and a ground-water budget are presented to render a better understanding of the hydrologic system with which water management will be concerned.

Low-field and high-field magnetic resonance contrast imaging of magnetoferritin as a pathological model system of iron accumulation

NASA Astrophysics Data System (ADS)

Strbak, Oliver; Balejcikova, Lucia; Baciak, Ladislav; Kovac, Jozef; Masarova-Kozelova, Marta; Krafcik, Andrej; Dobrota, Dusan; Kopcansky, Peter

2017-09-01

Various pathological processes including neurodegenerative disorders are associated with the accumulation of iron, while it is believed that a precursor of iron accumulation is ferritin. Physiological ferritin is due to low relaxivity, which results in only weak detection by magnetic resonance imaging (MRI) techniques. On the other hand, pathological ferritin is associated with disrupted iron homeostasis and structural changes in the mineral core, and should increase the hypointensive artefacts in MRI. On the basis of recent findings in respect to the pathological ferritin structure, we prepared the magnetoferritin particles as a possible pathological ferritin model system. The particles were characterised with dynamic light scattering, as well as with superconducting quantum interference device measurements. With the help of low-field (0.2 T) and high-field (4.7 T) MRI standard T 2-weighted protocols we found that it is possible to clearly distinguish between native ferritin as a physiological model system, and magnetoferritin as a pathological model system. Surprisingly, the T 2-weighted short TI inversion recovery protocol at low-field system showed the optimum contrast differentiation. Such findings are highly promising for exploiting the use of iron accumulation as a noninvasive diagnostics tool of pathological processes, where the magnetoferritin particles could be utilised as MRI iron quantification calibration samples.

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

PubMed

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

2018-06-05

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

NASA and Deere to study effects of low-g on iron processing

NASA Technical Reports Server (NTRS)

1981-01-01

A technical exchange agreement to study the effects of processing iron alloys in microgravity is described. Alloy solidification experiments are to be performed in the low-g facilities at Marshall Space Center. Deere is to prepare and evaluate the samples, and perform thermal characterization studies of the furnace used for melting and solidifying the samples. Experiment planning and analysis are to be performed jointly and data shared between the two parties. The technical exchange concept, developed by NASA to involve the private sector in low gravity research programs, is described. Other low gravity processing fields in which industry is invited to participate are listed.

When Less is More: Novel Mechanisms of Iron Conservation

PubMed Central

Bayeva, Marina; Chang, Hsiang-Chun; Wu, Rongxue; Ardehali, Hossein

2016-01-01

Disorders of iron homeostasis are very common, yet the molecular mechanisms of iron regulation remain understudied. Over 20 years have passed since the first characterization of iron regulatory proteins (IRP) as mediators of cellular iron deficiency response in mammals through iron acquisition. However, little is known about other mechanisms necessary for adaptation to low-iron states. In this review we present recent evidence that establishes existence of a new iron regulatory pathway aimed at iron conservation and optimization of iron use through suppression of non-essential iron-consuming processes. Moreover, we discuss the possible links between iron homeostasis and energy metabolism uncovered by studies of iron deficiency response. PMID:23948590

Biological iron oxidation by Gallionella spp. in drinking water production under fully aerated conditions.

PubMed

de Vet, W W J M; Dinkla, I J T; Rietveld, L C; van Loosdrecht, M C M

2011-11-01

Iron oxidation under neutral conditions (pH 6.5-8) may be a homo- or heterogeneous chemically- or a biologically-mediated process. The chemical oxidation is supposed to outpace the biological process under slightly alkaline conditions (pH 7-8). The iron oxidation kinetics and growth of Gallionella spp. - obligatory chemolithotrophic iron oxidizers - were assessed in natural, organic carbon-containing water, in continuous lab-scale reactors and full-scale groundwater trickling filters in the Netherlands. From Gallionella cell numbers determined by qPCR, balances were made for all systems. The homogeneous chemical iron oxidation occurred in accordance with the literature, but was retarded by a low water temperature (13 °C). The contribution of the heterogeneous chemical oxidation was, despite the presence of freshly formed iron oxyhydroxides, much lower than in previous studies in ultrapure water. This could be caused by the adsorption of natural organic matter (NOM) on the iron oxide surfaces. In the oxygen-saturated natural water with a pH ranging from 6.5 to 7.7, Gallionella spp. grew uninhibited and biological iron oxidation was an important, and probably the dominant, process. Gallionella growth was not even inhibited in a full-scale filter after plate aeration. From this we conclude that Gallionella spp. can grow under neutral pH and fully aerated conditions when the chemical iron oxidation is retarded by low water temperature and inhibition of the autocatalytic iron oxidation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Microbial diversity and iron oxidation at Okuoku-hachikurou Onsen, a Japanese hot spring analog of Precambrian iron formations.

PubMed

Ward, L M; Idei, A; Terajima, S; Kakegawa, T; Fischer, W W; McGlynn, S E

2017-11-01

Banded iron formations (BIFs) are rock deposits common in the Archean and Paleoproterozoic (and regionally Neoproterozoic) sedimentary successions. Multiple hypotheses for their deposition exist, principally invoking the precipitation of iron via the metabolic activities of oxygenic, photoferrotrophic, and/or aerobic iron-oxidizing bacteria. Some isolated environments support chemistry and mineralogy analogous to processes involved in BIF deposition, and their study can aid in untangling the factors that lead to iron precipitation. One such process analog system occurs at Okuoku-hachikurou (OHK) Onsen in Akita Prefecture, Japan. OHK is an iron- and CO 2 -rich, circumneutral hot spring that produces a range of precipitated mineral textures containing fine laminae of aragonite and iron oxides that resemble BIF fabrics. Here, we have performed 16S rRNA gene amplicon sequencing of microbial communities across the range of microenvironments in OHK to describe the microbial diversity present and to gain insight into the cycling of iron, oxygen, and carbon in this ecosystem. These analyses suggest that productivity at OHK is based on aerobic iron-oxidizing Gallionellaceae. In contrast to other BIF analog sites, Cyanobacteria, anoxygenic phototrophs, and iron-reducing micro-organisms are present at only low abundances. These observations support a hypothesis where low growth yields and the high stoichiometry of iron oxidized per carbon fixed by aerobic iron-oxidizing chemoautotrophs like Gallionellaceae result in accumulation of iron oxide phases without stoichiometric buildup of organic matter. This system supports little dissimilatory iron reduction, further setting OHK apart from other process analog sites where iron oxidation is primarily driven by phototrophic organisms. This positions OHK as a study area where the controls on primary productivity in iron-rich environments can be further elucidated. When compared with geological data, the metabolisms and mineralogy at OHK are most similar to specific BIF occurrences deposited after the Great Oxygenation Event, and generally discordant with those that accumulated before it. © 2017 John Wiley & Sons Ltd.

SULPHUR DIOXIDE LEACHING OF URANIUM CONTAINING MATERIAL

DOEpatents

Thunaes, A.; Rabbits, F.T.; Hester, K.D.; Smith, H.W.

1958-12-01

A process is described for extracting uranlum from uranium containing material, such as a low grade pitchblende ore, or mill taillngs, where at least part of the uraniunn is in the +4 oxidation state. After comminuting and magnetically removing any entrained lron particles the general material is made up as an aqueous slurry containing added ferric and manganese salts and treated with sulfur dioxide and aeration to an extent sufficient to form a proportion of oxysulfur acids to give a pH of about 1 to 2 but insufficient to cause excessive removal of the sulfur dioxide gas. After separating from the solids, the leach solution is adjusted to a pH of about 1.25, then treated with metallic iron in the presence of a precipitant such as a soluble phosphate, arsonate, or fluoride.

Millions of Boreal Shield Lakes can be used to Probe Archaean Ocean Biogeochemistry

NASA Astrophysics Data System (ADS)

Schiff, S. L.; Tsuji, J. M.; Wu, L.; Venkiteswaran, J. J.; Molot, L. A.; Elgood, R. J.; Paterson, M. J.; Neufeld, J. D.

2017-04-01

Life originated in Archaean oceans, almost 4 billion years ago, in the absence of oxygen and the presence of high dissolved iron concentrations. Early Earth oxidation is marked globally by extensive banded iron formations but the contributing processes and timing remain controversial. Very few aquatic habitats have been discovered that match key physico-chemical parameters of the early Archaean Ocean. All previous whole ecosystem Archaean analogue studies have been confined to rare, low sulfur, and permanently stratified lakes. Here we provide first evidence that millions of Boreal Shield lakes with natural anoxia offer the opportunity to constrain biogeochemical and microbiological aspects of early Archaean life. Specifically, we combined novel isotopic signatures and nucleic acid sequence data to examine processes in the anoxic zone of stratified boreal lakes that are naturally low in sulfur and rich in ferrous iron, hallmark characteristics predicted for the Archaean Ocean. Anoxygenic photosynthesis was prominent in total water column biogeochemistry, marked by distinctive patterns in natural abundance isotopes of carbon, nitrogen, and iron. These processes are robust, returning reproducibly after water column re-oxygenation following lake turnover. Evidence of coupled iron oxidation, iron reduction, and methane oxidation affect current paradigms of both early Earth and modern aquatic ecosystems.

A study on the selection of indigenous leaching-bacteria for effective bioleaching

NASA Astrophysics Data System (ADS)

Oh, S. J.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

2012-04-01

Bioleaching technology, which is based on the ability of microorganisms to transform solid compounds into soluble and extractable valuable elements that can be recovered, has been rapidly developed in recent decades for its advantages, which include mild reaction condition, low energy consumption, simple process, low environmental impact and being suitable for low grade mine tailings and residues. The bacteria activities (survival, adaptation of toxically environments etc.) in the bioleaching technology play a key role in the solubilization of metals. The purpose of this study was to selection of optimal leaching-bacteria through changed pH and redox potential on bio-oxidation in batch experiments for successful bioleaching technology. Twenty three indigenous bacteria used throughout this study, leaching-bacteria were obtained from various geochemical conditions; bacteria inhabitation type (acid mine drainage, mine wastes leachate and sulfur hot springs) and base-metal type (sulfur, sulfide, iron and coal). Bio-oxidation experiment result was showed that 9 cycles (1 cycle - 28days) after the leaching-bacteria were inoculated to a leaching medium, pH was observed decreasing and redox potential increased. In the bacteria inhabitation type, bio-oxidation of sulfur hot springs bacteria was greater than other types (acid mine drainage and mine wastes leachate). In addition, bio-oxidation on base-metal type was appeared sulfur was greater than other types (sulfide, iron and coal). This study informs basic knowledge when bacteria apply to eco-/economic resources utilization studies including the biomining and the recycling of mine waste system.

The SHOLO mill: make pallet parts and pulp chips from low-grade hardwoods

Treesearch

Hugh W. Reynolds; Charles J. Gatchell; Charles J. Gatchell

1970-01-01

SHOLO (from SHOrt Log) is a new solution to the old problem of profitably converting low-grade hardwood logs into products or product parts. It does away with the traditional and often uneconomical procedure of sawing low-grade logs into standard lumber and then converting this standard lumber into product parts. Instead, the SHOLO process is used to convert low-grade...

Beneficiation and leaching study of a muti-Au carrier and low grade refractory gold ore

NASA Astrophysics Data System (ADS)

Li, W. J.; Song, Y. S.; Chen, Y.; Cai, L. L.; Zhou, G. Y.

2017-09-01

Detailed mineralogy and beneficiation and leaching study of a muti-Au carrier, low grade refractory gold ore from a beneficiation plant in Henan Province, China, was investigated. Mineral liberation analysis, scanning electron microscopy, element phase analysis and etc. by a mineral liberation analyser were used for mineralogical characterization study of this ore. The present work describes an experimental study on the effect of traditional parameters (such as grinding fineness and reagent regimes), middling processing method and flowsheet construction on the total recovery and the assay of the floatation concentrate. Two-step floatation and part of middling combined to the floatation tailing for gold leaching process resulted in high gold grade (g.t-1) and gold recovery (%) for this refractory gold ore. This process opens the possibilities of maximizing Au grade and recoveries in a muti-Au carrier and low grade refractory gold ore where low recoveries are common.

Low levels of iron enhance UV/H2O2 efficiency at neutral pH.

PubMed

Ulliman, Sydney L; McKay, Garrett; Rosario-Ortiz, Fernando L; Linden, Karl G

2018-03-01

While the presence of iron is generally not seen as favorable for UV-based treatment systems due to lamp fouling and decreased UV transmittance, we show that low levels of iron can lead to improvements in the abatement of chemicals in the UV-hydrogen peroxide advanced oxidation process. The oxidation potential of an iron-assisted UV/H 2 O 2 (UV 254  + H 2 O 2  + iron) process was evaluated at neutral pH using iron levels below USEPA secondary drinking water standards (<0.3 mg/L). Para-chlorobenzoic acid (pCBA) was used as a hydroxyl radical (HO) probe to quantify HO steady state concentrations. Compounds degraded by different mechanisms including, carbamazepine (CBZ, HO oxidation) and N-nitrosodimethylamine (NDMA, direct photolysis), were used to investigate the effect of iron on compound degradation for UV/H 2 O 2 systems. The effects of iron species (Fe 2+ and Fe 3+ ), iron concentration (0-0.3 mg/L), H 2 O 2 concentration (0-10 mg/L) and background water matrix (low-carbon tap (LCT) and well water) on HO production and compound removal were examined. Iron-assisted UV/H 2 O 2 efficiency was most influenced by the target chemical and the water matrix. Added iron to UV/H 2 O 2 was shown to increase the steady-state HO concentration by approximately 25% in all well water scenarios. While CBZ removal was unchanged by iron addition, 0.3 mg/L iron improved NDMA removal rates in both LCT and well water matrices by 15.1% and 4.6% respectively. Furthermore, the combination of UV/Fe without H 2 O 2 was also shown to enhance NDMA removal when compared to UV photolysis alone indicating the presence of degradation pathways other than HO oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Did the Kiruna iron ores form as a result of a metasomatic or igneous process? New U-Pb and Nd data for the iron oxide apatite ores and their host rocks in the Norrbotten region of northern Sweden

NASA Astrophysics Data System (ADS)

Westhues, A.; Hanchar, J. M.; Whitehouse, M. J.; Fisher, C. M.

2012-12-01

A number of iron deposits near Kiruna in the Norrbotten region of northern Sweden are of the iron oxide apatite (IOA) type of deposits; also referred to as Kiruna-type deposits. They are commonly considered a subgroup or end-member of iron oxide copper gold (IOCG) deposits, containing no economic grades of copper or gold. Both IOCG and IOA deposits are characterized by abundant low-Ti Fe oxides, an enrichment in REE, and intense sodium and potassium wall-rock alteration adjacent to the ores. Deposits of these types are of a great economic importance, not only for iron, but also for other elements such as rare earth elements (REE) or uranium. Kiruna, the type locality of the IOA type of mineral deposits, is the focus of this study. Despite a century-long mining history and 2500 Mt of iron ore produced in the region to date (with grades of 30 to 70 wt.% Fe), the genesis of these deposits is poorly understood: theories of a magmatic vs. a hydrothermal or metasomatic origin have been debated, and the timing of mineralization of the ores in the Norbotten region has never been directly dated. The results anticipated from this study will provide a better understanding of the nature of the IOA type of mineral deposits and their relation to IOCG deposits such as Olympic Dam in Australia. An array of geochemical methods is used in order to gain insights on the emplacement history of the host rocks, their subsequent alteration, and the ore genesis of these deposits. This includes in situ U/Pb geochronology of zircon, monazite, and titanite to constrain the timing between host rock emplacement, alteration and mineralization. Isotopic data from whole rocks and in situ at mineral scale will provide constraints on the involvement of hydrothermal fluids and their possible sources, as well as on the sources of Fe, U, and the REE. Newly obtained Sm-Nd isotopic data points to distinct source differences between host rocks, ore and alteration related samples. Preliminary in situ U-Pb dating of zircon from both host rock and ore samples confirms a previously documented event around 1880 - 1900 Ma in the Norrbotten region. However, U-Pb in monazite from an ore sample suggests a further event at ca. 1650 Ma, a period of known activity in Fennoscandia. Further investigation and more U-Pb data are needed to confirm those dates and how the iron mineralization is related to those two events. The combination of U-Th-Pb ages, tracer isotopes and trace element abundances at mineral scale (e.g., Lu-Hf in zircon, and Sm-Nd in monazite, apatite, titanite), along with the O isotopic composition of zircon, will be used to decipher whether the Kiruna iron ore deposits are of metasomatic or igneous origin. Overall, the study also intends to develop a predictive model for exploration of similar iron oxide apatite deposits worldwide.

Increasing minority carrier lifetime in as-grown multicrystalline silicon by low temperature internal gettering

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

Al-Amin, M., E-mail: m.al-amin@warwick.ac.uk; Murphy, J. D., E-mail: john.d.murphy@warwick.ac.uk

2016-06-21

We report a systematic study into the effects of long low temperature (≤500 °C) annealing on the lifetime and interstitial iron distributions in as-grown multicrystalline silicon (mc-Si) from different ingot height positions. Samples are characterised in terms of dislocation density, and lifetime and interstitial iron concentration measurements are made at every stage using a temporary room temperature iodine-ethanol surface passivation scheme. Our measurement procedure allows these properties to be monitored during processing in a pseudo in situ way. Sufficient annealing at 300 °C and 400 °C increases lifetime in all cases studied, and annealing at 500 °C was only found to improve relatively poormore » wafers from the top and bottom of the block. We demonstrate that lifetime in poor as-grown wafers can be improved substantially by a low cost process in the absence of any bulk passivation which might result from a dielectric surface film. Substantial improvements are found in bottom wafers, for which annealing at 400 °C for 35 h increases lifetime from 5.5 μs to 38.7 μs. The lifetime of top wafers is improved from 12.1 μs to 23.8 μs under the same conditions. A correlation between interstitial iron concentration reduction and lifetime improvement is found in these cases. Surprisingly, although the interstitial iron concentration exceeds the expected solubility values, low temperature annealing seems to result in an initial increase in interstitial iron concentration, and any subsequent decay is a complex process driven not only by diffusion of interstitial iron.« less

Millions of Boreal Shield Lakes can be used to Probe Archaean Ocean Biogeochemistry

PubMed Central

Schiff, S. L.; Tsuji, J. M.; Wu, L.; Venkiteswaran, J. J.; Molot, L. A.; Elgood, R. J.; Paterson, M. J.; Neufeld, J. D.

2017-01-01

Life originated in Archaean oceans, almost 4 billion years ago, in the absence of oxygen and the presence of high dissolved iron concentrations. Early Earth oxidation is marked globally by extensive banded iron formations but the contributing processes and timing remain controversial. Very few aquatic habitats have been discovered that match key physico-chemical parameters of the early Archaean Ocean. All previous whole ecosystem Archaean analogue studies have been confined to rare, low sulfur, and permanently stratified lakes. Here we provide first evidence that millions of Boreal Shield lakes with natural anoxia offer the opportunity to constrain biogeochemical and microbiological aspects of early Archaean life. Specifically, we combined novel isotopic signatures and nucleic acid sequence data to examine processes in the anoxic zone of stratified boreal lakes that are naturally low in sulfur and rich in ferrous iron, hallmark characteristics predicted for the Archaean Ocean. Anoxygenic photosynthesis was prominent in total water column biogeochemistry, marked by distinctive patterns in natural abundance isotopes of carbon, nitrogen, and iron. These processes are robust, returning reproducibly after water column re-oxygenation following lake turnover. Evidence of coupled iron oxidation, iron reduction, and methane oxidation affect current paradigms of both early Earth and modern aquatic ecosystems. PMID:28447615

Occurrence and Characterization Microstructure of Iron Impurities in Halloysite.

PubMed

Liu, Rong; Yan, Chunjie; Wang, Hongquan; Xiao, Guoqi; Tu, Dong

2015-09-01

The quality of the clays and over all halloysite are mostly associated with minor amounts of ferruginous impurities content, since this element gives an undesirable reddish color to the halloysite mineral. Hence, finding out the modes of occurrence of iron in halloysite is of prime importance in the value addition and optimum utilization of halloysite. In order to analyze the occurrence of iron impurities in halloysite, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were combined with wet chemical analysis methods to study the low-grade halloysite. The results indicated that the mineral phases of iron impurities in the concentrates are mainly composed of amounts of magnetite, goethite and hematite. Two types of occurrences for iron impurities have been found. One is single crystalline mineral consist in the halloysite, which contains three different phases of Goethite FeO(OH) (44.75%), Magnetite Fe3O4 (27.43%) and Hematite Fe2O3 (31.96%). The other is amorphous Fe-Al-Si glial materials. This study is of significance in the theoretical research on the halloysite mineralogy and in the developmental practice of halloysite in coal measures.

Corrosion resistance of BIS 2062-grade steel coated with nano-metal-oxide mixtures of iron, cerium, and titanium in the marine environment

NASA Astrophysics Data System (ADS)

Ashraf, P. Muhamed; Anuradha, R.

2018-02-01

BIS 2062-grade carbon steel is extensively used for fishing boat construction. The steel is highly susceptible to corrosion on the hull and welding joints under marine environment. Here, we demonstrate the application of a novel multifunctional nano-metal-oxide mixture comprised of iron, titanium, and cerium as a marine coating to prevent corrosion. The electrochemical performance of nano-metal-oxide mixture coatings, applied over boat-building steel, was evaluated at 3.5% NaCl medium. The nano-mixture surface coatings showed an efficient corrosion resistance with increased polarization resistance of 6043 Ω cm2 and low corrosion current density of 3.53 × 10-6 A cm-2. The electrochemical impedance spectral data exhibited improvement in the polarization resistance of outermost surface and internal layers. The coating responded faster recovery to normal state when subjected to an induced stress over the coating. The nano-material in the coating behaves as a semiconductor; this enhanced electronic activity over the surface of the steel.

SOUTHERN MASSANUTTEN ROADLESS AREA, VIRGINIA.

USGS Publications Warehouse

Lesure, Frank G.; Chatman, Mark L.

1984-01-01

The Southern Massanutten Roadless Area is in the George Washington National Forest in the Shenandoah Valley of Page and Rockingham Counties, Virginia. According to mineral surveys of the area, inferred resources of low-grade iron occur at two mines in folded Paleozoic sedimentary rocks. The iron resources consist of 120,000 long tons of clayey and sandy limonite. Other mineral resources occur in the area including extensive areas of high-silica sandstone, shale suitable for making brick, and limestone suitable for crushed stone and agricultural lime. The potential for the occurrence of oil or natural gas resources cannot be evaluated from the available data. The nonmetallic mineral resources are of limited importance because of relative inaccessibility as compared to large accessible resources outside the roadless area.

Arterial oxygen content is precisely maintained by graded erythrocytotic responses in settings of high/normal serum iron levels, and predicts exercise capacity: an observational study of hypoxaemic patients with pulmonary arteriovenous malformations.

PubMed

Santhirapala, Vatshalan; Williams, Louisa C; Tighe, Hannah C; Jackson, James E; Shovlin, Claire L

2014-01-01

Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without concurrent hypoxic pulmonary vasoreactivity. 165 consecutive unselected patients with pulmonary arteriovenous malformations were studied, in 98 cases, pre/post embolisation treatment. 159 (96%) had hereditary haemorrhagic telangiectasia. Arterial oxygen content was calculated by SaO2 x haemoglobin x 1.34/100. There was wide variation in SaO2 on air (78.5-99, median 95)% but due to secondary erythrocytosis and resultant polycythaemia, SaO2 explained only 0.1% of the variance in arterial oxygen content per unit blood volume. Secondary erythrocytosis was achievable with low iron stores, but only if serum iron was high-normal: Low serum iron levels were associated with reduced haemoglobin per erythrocyte, and overall arterial oxygen content was lower in iron deficient patients (median 16.0 [IQR 14.9, 17.4]mls/dL compared to 18.8 [IQR 17.4, 20.1]mls/dL, p<0.0001). Exercise tolerance appeared unrelated to SaO2 but was significantly worse in patients with lower oxygen content (p<0.0001). A pre-defined athletic group had higher Hb:SaO2 and serum iron:ferritin ratios than non-athletes with normal exercise capacity. PAVM embolisation increased SaO2, but arterial oxygen content was precisely restored by a subsequent fall in haemoglobin: 86 (87.8%) patients reported no change in exercise tolerance at post-embolisation follow-up. Haemoglobin and oxygen measurements in isolation do not indicate the more physiologically relevant oxygen content per unit blood volume. This can be maintained for SaO2 ≥78.5%, and resets to the same arterial oxygen content after correction of hypoxaemia. Serum iron concentrations, not ferritin, seem to predict more successful polycythaemic responses.

Arterial Oxygen Content Is Precisely Maintained by Graded Erythrocytotic Responses in Settings of High/Normal Serum Iron Levels, and Predicts Exercise Capacity: An Observational Study of Hypoxaemic Patients with Pulmonary Arteriovenous Malformations

PubMed Central

Santhirapala, Vatshalan; Williams, Louisa C.; Tighe, Hannah C.; Jackson, James E.; Shovlin, Claire L.

2014-01-01

Background Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without concurrent hypoxic pulmonary vasoreactivity. Methodology 165 consecutive unselected patients with pulmonary arteriovenous malformations were studied, in 98 cases, pre/post embolisation treatment. 159 (96%) had hereditary haemorrhagic telangiectasia. Arterial oxygen content was calculated by SaO2 x haemoglobin x 1.34/100. Principal Findings There was wide variation in SaO2 on air (78.5–99, median 95)% but due to secondary erythrocytosis and resultant polycythaemia, SaO2 explained only 0.1% of the variance in arterial oxygen content per unit blood volume. Secondary erythrocytosis was achievable with low iron stores, but only if serum iron was high-normal: Low serum iron levels were associated with reduced haemoglobin per erythrocyte, and overall arterial oxygen content was lower in iron deficient patients (median 16.0 [IQR 14.9, 17.4]mls/dL compared to 18.8 [IQR 17.4, 20.1]mls/dL, p<0.0001). Exercise tolerance appeared unrelated to SaO2 but was significantly worse in patients with lower oxygen content (p<0.0001). A pre-defined athletic group had higher Hb:SaO2 and serum iron:ferritin ratios than non-athletes with normal exercise capacity. PAVM embolisation increased SaO2, but arterial oxygen content was precisely restored by a subsequent fall in haemoglobin: 86 (87.8%) patients reported no change in exercise tolerance at post-embolisation follow-up. Significance Haemoglobin and oxygen measurements in isolation do not indicate the more physiologically relevant oxygen content per unit blood volume. This can be maintained for SaO2 ≥78.5%, and resets to the same arterial oxygen content after correction of hypoxaemia. Serum iron concentrations, not ferritin, seem to predict more successful polycythaemic responses. PMID:24637882

Production of the natural iron chelator deferriferrichrysin from Aspergillus oryzae and evaluation as a novel food-grade antioxidant.

PubMed

Todokoro, Takehiko; Fukuda, Katsuharu; Matsumura, Kengo; Irie, Motoko; Hata, Yoji

2016-07-01

Deferriferrichrysin (Dfcy) is a siderophore found in foods fermented by Aspergillus oryzae and is a promising candidate for an antioxidant food additive because of its high binding constant toward iron. However, the Dfcy concentration is typically low in foods and cultures. We optimised culture conditions to improve Dfcy production to 2800 mg L(-1) from 22.5 mg L(-1) under typical conditions. Then, we evaluated the potential of Dfcy as a food additive by measuring its safety, stability, and antioxidant activity. Dfcy was sufficiently stable that over 90% remained after pasteurisation at 63 °C for 30 min at pH 3-11, or after sterilisation at 120 °C for 4 min at pH 4-6. Dfcy showed high antioxidant activity in an oil-in-water model, where inhibition of lipid oxidation was measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assays. Dfcy decreased PV and TBARS by 83% and 75%, respectively. Antioxidant activity of Dfcy was equal to or higher than that of the synthetic chelator EDTA. Our study provides the first practical method for production of Dfcy. Dfcy can be a novel food-grade antioxidant and the first natural alternative to the synthesised iron chelator EDTA. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

A neurogenic tumor containing a low-grade malignant peripheral nerve sheath tumor (MPNST) component with loss of p16 expression and homozygous deletion of CDKN2A/p16: a case report showing progression from a neurofibroma to a high-grade MPNST.

PubMed

Tajima, Shogo; Koda, Kenji

2015-01-01

Development of malignant peripheral nerve sheath tumors (MPNSTs) is a stepwise process that involves the alteration of many cell cycle regulators and the double inactivation of the NF1 gene. Inactivation of the TP53 gene and deletion of the CDKN2A/p16 gene are known to play an important role in the process. Herein, we present a 19-year-old man with a familial history of neurofibromatosis type 1, in whom the tumor arose from the intercostal nerve and showed 3 components: a neurofibroma, a low-grade MPNST, and a high-grade MPNST. Loss of p16 expression and homozygous deletion of the CDKN2A/p16 gene were observed in both the low-grade and the high-grade MPNST. In contrast to low-grade MPNSTs, high-grade MPNSTs generally tend to lose expression of p16 and harbor homozygous deletion of the CDKN2A/p16 gene. Loss of p16 expression and homozygous deletion of the CDKN2A/p16 gene in low-grade MPNST in our case might be related to its progression to high-grade MPNST. To the best of our knowledge, this is the first study correlating the p16 expression status and CDKN2A/p16 gene alteration in low-grade MPNSTs.

Behavioral and developmental effects of preventing iron-deficiency anemia in healthy full-term infants.

PubMed

Lozoff, Betsy; De Andraca, Isidora; Castillo, Marcela; Smith, Julia B; Walter, Tomas; Pino, Paulina

2003-10-01

To determine the behavioral and developmental effects of preventing iron-deficiency anemia in infancy. Healthy full-term Chilean infants who were free of iron-deficiency anemia at 6 months were assigned to high- or low-iron groups or to high- or no-added-iron groups. Behavioral/developmental outcomes at 12 months of age included overall mental and motor test scores and specific measures of motor functioning, cognitive processing, and behavior. There were no differences between high- and low-iron groups in the prevalence of iron-deficiency anemia or behavioral/developmental outcome, and they were combined to form an iron-supplemented group (n = 1123) for comparison with the no-added-iron group (n = 534). At 12 months, iron-deficiency anemia was present in 3.1% and 22.6% of the supplemented and unsupplemented groups, respectively. The groups differed in specific behavioral/developmental outcomes but not on global test scores. Infants who did not receive supplemental iron processed information slower. They were less likely to show positive affect, interact socially, or check their caregivers' reactions. A smaller proportion of them resisted giving up toys and test materials, and more could not be soothed by words or objects when upset. They crawled somewhat later and were more likely to be tremulous. The results suggest that unsupplemented infants responded less positively to the physical and social environment. The observed differences seem to be congruent with current understanding of the effects of iron deficiency on the developing brain. The study shows that healthy full-term infants may receive developmental and behavioral benefits from iron supplementation in the first year of life.

A Systems Biology Approach to Iron Metabolism

PubMed Central

Chifman, J.; Laubenbacher, R.; Torti, S.V.

2015-01-01

Iron is critical to the survival of almost all living organisms. However, inappropriately low or high levels of iron are detrimental and contribute to a wide range of diseases. Recent advances in the study of iron metabolism have revealed multiple intricate pathways that are essential to the maintenance of iron homeostasis. Further, iron regulation involves processes at several scales, ranging from the subcellular to the organismal. This complexity makes a systems biology approach crucial, with its enabling technology of computational models based on a mathematical description of regulatory systems. Systems biology may represent a new strategy for understanding imbalances in iron metabolism and their underlying causes. PMID:25480643

Acidic processing of mineral dust iron by anthropogenic compounds over the north Pacific Ocean

NASA Astrophysics Data System (ADS)

Solmon, F.; Chuang, P. Y.; Meskhidze, N.; Chen, Y.

2009-01-01

Atmospheric processing of mineral aerosol by anthropogenic pollutants may be an important process by which insoluble iron can be transformed into soluble forms and become available to oceanic biota. Observations of the soluble iron fraction in atmospheric aerosol exhibit large variability, which is poorly represented in models. In this study, we implemented a dust iron dissolution scheme in a global chemistry transport model (GEOS-Chem). The model is applied over the North Pacific Ocean during April 2001, a period when concentrations of dust and pollution within the east Asia outflow were high. Simulated fields of many key chemical constituents compare reasonably well with available observations, although some discrepancies are identified and discussed. In our simulations, the production of soluble iron varies temporally and regionally depending on pollution-to-dust ratio, primarily due to strong buffering by calcite. Overall, we show that the chemical processing mechanism produces significant amounts of dissolved iron reaching and being deposited in remote regions of the Pacific basin, with some seasonal variability. Simulated enhancements in particulate soluble iron fraction range from 0.5% to 6%, which is consistent with the observations. According to our simulations, ˜30% to 70% of particulate soluble iron over the North Pacific Ocean basin can be attributed to atmospheric processing. On the basis of April 2001 monthly simulations, sensitivity tests suggest that doubling SO2 emissions can induce a significant increase (13% on average, up to 40% during specific events) in dissolved iron production and deposition to the remote Pacific. We roughly estimate that half of the primary productivity induced by iron deposition in a north Pacific high-nutrient low-chlorophyll region is due to soluble iron derived from anthropogenic chemical processing of Asian aerosol.

Chemsheet as a Simulation Platform for Pyrometallurgical Processes

NASA Astrophysics Data System (ADS)

Penttilä, Karri; Salminen, Justin; Tripathi, Nagendra; Koukkari, Pertti

ChemSheet is a thermodynamic multi-phase multi-component simulation software, which is used as an Add-in in Microsoft Excel. In ChemSheet, the unique Constrained Gibbs free energy method can be used to include dynamic constraints and reaction rates of kinetically slow reactions, yet retaining full consistency of the multiphase thermodynamic model. With appropriate data, ChemSheet models can be used to simulate reactors and processes in all fields of thermochemistry. The presentation will cover off-line modeling of Cu-flash smelters and advanced thermochemical simulation coupled with on-line process control of Cu-Ni smelting. The presentation will describe an off-line model of Cu-smelter based on critically assessed properties of the Al-Ca-Cu-Fe-O-S-Si -system (slag, matte and liquid metal) by using the quasichemical model. A four-stage reactor model (shaft, settler, uptake and bath) is used for optimizing process parameters and feed particle distribution. As a second example, an advanced thermochemical model of a Ni-Cu sulphide smelting plant will be given. The on-line model covers the operation of treating Ni-Cu-S concentrate via roasters, electric furnace and converters, producing a high grade Bessemer matte product for further refining. The model integrates the thermochemistry of the roasters and electric furnace, and predicts important process parameters such as degree of sulphur elimination in the fluid-bed roasters, matte grade, iron metallization, slag losses and the iron to silica ratio in the electric furnace slag. Both models can be used to assist process engineers and operators in calculating the addition rates of coke, flux and air for different feed scenarios.

Lead iron phosphate glass as a containment medium for disposal of high-level nuclear waste

DOEpatents

Boatner, Lynn A.; Sales, Brian C.

1989-01-01

Lead-iron phosphate glasses containing a high level of Fe.sub.2 O.sub.3 for use as a storage medium for high-level radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste, a highly corrosion resistant, homogeneous, easily processed glass can be formed. For corroding solutions at 90.degree. C., with solution pH values in the range between 5 and 9, the corrosion rate of the lead-iron phosphate nuclear waste glass is at least 10.sup.2 to 10.sup.3 times lower than the corrosion rate of a comparable borosilicate nuclear waste glass. The presence of Fe.sub.2 O.sub.3 in forming the lead-iron phosphate glass is critical. Lead-iron phosphate nuclear waste glass can be prepared at temperatures as low as 800.degree. C., since they exhibit very low melt viscosities in the 800.degree. to 1050.degree. C. temperature range. These waste-loaded glasses do not readily devitrify at temperatures as high as 550.degree. C. and are not adversely affected by large doses of gamma radiation in H.sub.2 O at 135.degree. C. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear wasteforms.

Evaluation of ground granulated iron blast-furnace slag : grade-100.

DOT National Transportation Integrated Search

2002-09-01

Currently, the use of grade-120 Granulated Ground Blast Furnace Slag (GGBFS) is incorporated into the specifications of LA DOTD concrete mixes. This study evaluates grade-100 GGBFS and its effect on the properties of hydraulic cement concretes used i...

Recovery of Tungsten and Molybdenum from Low-Grade Scheelite

NASA Astrophysics Data System (ADS)

Li, Yongli; Yang, Jinhong; Zhao, Zhongwei

2017-10-01

With most high-quality tungsten ores being exhausted, the enhancement of low-grade scheelite concentrates processing has attracted a great deal of attention. The objective of this study is to develop a method to maximize the recovery tungsten and molybdenum from a low-grade scheelite via a new acid leaching process followed by solvent extraction. Under optimal conditions (350 g/L H2SO4, 95°C, and 2 h), approximately 99.8% of tungsten and 98% of molybdenum were leached out. In the subsequent solvent extraction process, more than 99% of the tungsten and molybdenum were extracted with a co-extraction system (50% TBP, 30% HDEHP, and 10% 2-octanol in kerosene) using a three-stage cross-flow extraction. The raffinate can be recycled for the next leaching process after replenishing the H2SO4 to the initial value (approximately 350 g/L). Based on these results, a conceptual flowsheet is presented to recover tungsten and molybdenum from the low-grade scheelite.

Carbon Isotopic Heterogeneity of Graphite in the San Juan Mass of the Campo Del Cielo IAB Iron Meteorite

NASA Technical Reports Server (NTRS)

Maruoka, T.; Kurat, G.; Zinner, E.; Varela, M. E.; Ametrano, S. J.

2003-01-01

The origin of IAB iron meteorites is still a matter of debate. It is generally believed that iron meteorites originated from molten cores in small planetesimals because the fractionation trend of trace elements (e.g., Ir, Ge, Ga, etc. vs. Ni) for most iron meteorites can be more or less explained by fractional crystallization from metal melts. However, this process cannot produce trace element characteristics of the IAB (and other) iron meteorites. To explain these trace element abundance patterns, several models have been proposed. Although most of these models require a high temperature, clear evidence has recently been obtained for a sub-solidus formation of IAB iron meteorites from noble gas analyses. Moreover, heterogeneous distributions of some trace elements in metal and other phases also suggest a low temperature origin of at least some IAB iron meteorites. Here we use the carbon isotopic compositions of graphite to constrain the origin of IAB iron meteorites. Our data confirm a possible low temperature origin of IAB iron meteorites.

Explosion-assisted preparation of dispersed gold-bearing different-grade ore for selective mining

NASA Astrophysics Data System (ADS)

Trubachev, AI; Zykov, NV

2017-02-01

It is found that there are transient zones (between quality and off-quality ore areas) with the respective content of useful component in an ore body, and a variant of explosive treatment of such zones before the selective mining is put forward. Practicability of two processing technologies is evaluated: processing of high-grade and low-grade ore from the transient zones and heap leaching of metals from the low-grade and impoverished ore. Open mining technology is conventional truck-and-shovel scheme, with distributed ore flows to processing plant and (or) to heap leaching, which generally enhances the mine efficiency.

A case in support of implementing innovative bio-processes in the metal mining industry.

PubMed

Sánchez-Andrea, Irene; Stams, Alfons J M; Weijma, Jan; Gonzalez Contreras, Paula; Dijkman, Henk; Rozendal, Rene A; Johnson, D Barrie

2016-06-01

The metal mining industry faces many large challenges in future years, among which is the increasing need to process low-grade ores as accessible higher grade ores become depleted. This is against a backdrop of increasing global demands for base and precious metals, and rare earth elements. Typically about 99% of solid material hauled to, and ground at, the land surface currently ends up as waste (rock dumps and mineral tailings). Exposure of these to air and water frequently leads to the formation of acidic, metal-contaminated run-off waters, referred to as acid mine drainage, which constitutes a severe threat to the environment. Formation of acid drainage is a natural phenomenon involving various species of lithotrophic (literally 'rock-eating') bacteria and archaea, which oxidize reduced forms of iron and/or sulfur. However, other microorganisms that reduce inorganic sulfur compounds can essentially reverse this process. These microorganisms can be applied on industrial scale to precipitate metals from industrial mineral leachates and acid mine drainage streams, resulting in a net improvement in metal recovery, while minimizing the amounts of leachable metals to the tailings storage dams. Here, we advocate that more extensive exploitation of microorganisms in metal mining operations could be an important way to green up the industry, reducing environmental risks and improving the efficiency and the economy of metal recovery. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Method for reducing iron losses in an iron smelting process

DOEpatents

Sarma, B.; Downing, K.B.

1999-03-23

A process of smelting iron that comprises the steps of: (a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; (b) maintaining conditions in said reactor to cause (1) at least some of the iron oxide to be chemically reduced, (2) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (3) carbon monoxide gas to rise through the slag; (c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and (d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: (1) keep the temperature of the molten iron at or below about 1550 C and (2) keep the slag weight at or above about 0.8 ton per square meter. 13 figs.

Method for reducing iron losses in an iron smelting process

DOEpatents

Sarma, Balu; Downing, Kenneth B.

1999-01-01

A process of smelting iron that comprises the steps of: a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance; b) maintaining conditions in said reactor to cause (i) at least some of the iron oxide to be chemically reduced, (ii) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (iii) carbon monoxide gas to rise through the slag; c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; and d) releasing from the reactor an offgas effluent, is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to: e) keep the temperature of the molten iron at or below about 1550.degree. C. and f) keep the slag weight at or above about 0.8 tonne per square meter.

Plastid proteomics for elucidating iron limited remodeling of plastid physiology in diatoms

NASA Astrophysics Data System (ADS)

Gomes, K. M.; Nunn, B. L.; Jenkins, B. D.

2016-02-01

Diatoms are important primary producers in the world's oceans and their growth is constrained in large regions by low iron availability. This low iron-induced limitation of primary production is due to the requirement for iron in components of essential metabolic pathways including key chloroplast functions such as photosynthesis and nitrate assimilation. Diatoms can bloom and accumulate high biomass during introduction of iron into low iron waters, indicating adaptations allowing for their survival in iron-limited waters and rapid growth when iron becomes more abundant. Prior studies have shown that under iron limited stress, diatoms alter plastid-specific processes including components of electron transport, size of light harvesting capacity and chlorophyll content, suggesting plastid-specific protein regulation. Due to their complex evolutionary history, resulting from a secondary endosymbiosis, knowledge regarding the complement of plastid localized proteins remains limited in comparison to other model photosynthetic organisms. While in-silico prediction of diatom protein localization provides putative candidates for plastid-localization, these analyses can be limited as most plastid prediction models were developed using plants, primary endosymbionts. In order to characterize proteins enriched in diatom chloroplast and to understand how the plastid proteome is remodeled in response to iron limitation, we used mass spectrometry based proteomics to compare plastid- enriched protein fractions from Thalassiosira pseudonana, grown in iron replete and limited conditions. These analyses show that iron stress alters regulation of major metabolic pathways in the plastid including the Calvin cycle and fatty acid synthesis. These components provide promising targets to further characterize the plastid specific response to iron limitation.

Benefaction studies on the Hasan Celebi magnetite deposit, Turkey

USGS Publications Warehouse

Pressler, Jean W.; Akar, Ali

1972-01-01

Bench-scale and semicontinuous tests were performed on surface, trench, and diamond drill core samples from the Hasan Celebi low-grade magnetite deposit to determine the optimum benefication procedures utilizing wet magnetic separation techniques. Composite core samples typically contain about 27 percent recoverable magnetite and require crushing and grinding through 1 mm in size to insure satisfactory separation of the gangue from the magnetite. Regrinding and cleaning the magnetite concentrate to 80 percent minus 150-mesh is necessary to obtain an optimum of 66 percent iron. Semicontinuous pilot-plant testing with the wet magnetic drum using the recycled middling technique indicates that as much as 83 percent of the acid-soluble iron can be recovered into a concentrate containing 66 percent iron, with minimum deleterious elements. This represents 27 weight percent of the original ore. Further tests will continue when the Maden Tetkik ve Arama Enstitusu (MTA) receives 24 tons of bulk sample from an exploratory drift and cross-cut now being driven through a section of the major reserve area.

Iron oxide-mediated semiconductor photocatalysis vs. heterogeneous photo-Fenton treatment of viruses in wastewater. Impact of the oxide particle size.

PubMed

Giannakis, Stefanos; Liu, Siting; Carratalà, Anna; Rtimi, Sami; Talebi Amiri, Masoud; Bensimon, Michaël; Pulgarin, César

2017-10-05

The photo-Fenton process is recognized as a promising technique towards microorganism disinfection in wastewater, but its efficiency is hampered at near-neutral pH operating values. In this work, we overcome these obstacles by using the heterogeneous photo-Fenton process as the default disinfecting technique, targeting MS2 coliphage in wastewater. The use of low concentrations of iron oxides in wastewater without H 2 O 2 (wüstite, maghemite, magnetite) has demonstrated limited semiconductor-mediated MS2 inactivation. Changing the operational pH and the size of the oxide particles indicated that the isoelectric point of the iron oxides and the active surface area are crucial in the success of the process, and the possible underlying mechanisms are investigated. Furthermore, the addition of low amounts of Fe-oxides (1mgL -1 ) and H 2 O 2 in the system (1, 5 and 10mgL -1 ) greatly enhanced the inactivation process, leading to heterogeneous photo-Fenton processes on the surface of the magnetically separable oxides used. Additionally, photo-dissolution of iron in the bulk, lead to homogeneous photo-Fenton, further aided by the complexation by the dissolved organic matter in the solution. Finally, we assess the impact of the presence of the bacterial host and the difference caused by the different iron sources (salts, oxides) and the Fe-oxide size (normal, nano-sized). Copyright © 2017 Elsevier B.V. All rights reserved.

Decoupling of paramagnetic and ferrimagnetic AMS development during the experimental chemical compaction of illite shale powder

NASA Astrophysics Data System (ADS)

Bruijn, Rolf H. C.; Almqvist, Bjarne S. G.; Hirt, Ann M.; Benson, Philip M.

2013-03-01

Inclination shallowing of detrital remanent magnetization in sedimentary strata has solely been constrained for the mechanical processes associated with mud deposition and shallow compaction of clay-rich sediment, even though a significant part of mud diagenesis involves chemical compaction. Here we report, for the first time, on the laboratory simulation of magnetic assemblage development in a chemically compacting illite shale powder of natural origin. The experimental procedure comprised three compaction stages that, when combined, simulate the diagenesis and low-grade metamorphism of illite mud. First, the full extent of load-sensitive mechanical compaction is simulated by room temperature dry axial compression. Subsequently, temperature controlled chemical compaction is initiated by exposing the sample in two stages to amphibolite or granulite facies conditions (temperature is 490 to 750°C and confining pressure is 170 or 300 MPa) both in the absence (confining pressure only) and presence of a deformation stress field (axial compression or confined torsion). Thermodynamic equilibrium in the last two compaction stages was not reached, but illite and mica dehydroxylation initiated, thus providing a wet environment. Magnetic properties were characterized by magnetic susceptibility and its anisotropy (AMS) in both high- and low-applied field. Acquisition of isothermal remanent magnetization (IRM), stepwise three-component thermal de-magnetization of IRM and first-order reversal curves were used to characterize the remanence-bearing minerals. During the chemical compaction experiments ferrimagnetic iron-sulphides formed after reduction of magnetite and detrital pyrite in a low sulphur fugacity environment. The degree of low-field AMS is unaffected by porosity reduction from 15 to ˜1 per cent, regardless of operating conditions and compaction history. High-field paramagnetic AMS increases with compaction for all employed stress regimes and conditions, and is attributed to illite transformation to iron-bearing mica. AMS of authigenic iron-sulphide minerals remained constant during compaction indicating an independence of ferrimagnetic fabric development to chemical compaction in illite shale powder. The decoupling of paramagnetic and ferrimagnetic AMS development during chemical compaction of pelite contrasts with findings from mechanical compaction studies.

Effect of Iron Containing Supplements on Rats’ Dental Caries Progression

PubMed Central

Eshghi, AR.; Kowsari-Isfahan, R.; Rezaiefar, M.; Razavi, M.; Zeighami, S.

2012-01-01

Objective: Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children’s diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Materials and Methods: Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. Results: The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Conclusion: Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen. PMID:22924097

Effect of iron containing supplements on rats' dental caries progression.

PubMed

Eshghi, Ar; Kowsari-Isfahan, R; Rezaiefar, M; Razavi, M; Zeighami, S

2012-01-01

Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children's diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen.

Innovative instrumentation for mineralogical and elemental analyses of solid extraterrestrial surfaces: The Backscatter Moessbauer Spectrometer/X Ray Fluorescence analyzer (BaMS/XRF)

NASA Technical Reports Server (NTRS)

Shelfer, T. D.; Morris, Richard V.; Nguyen, T.; Agresti, D. G.; Wills, E. L.

1994-01-01

We have developed a four-detector research-grade backscatter Moessbauer spectrometer (BaMS) instrument with low resolution x-ray fluorescence analysis (XRF) capability. A flight-qualified instrument based on this design would be suitable for use on missions to the surfaces of solid solar-system objects (Moon, Mars, asteroids, etc.). Target specifications for the flight instrument are as follows: mass less than 500 g; volumes less than 300 cu cm; and power less than 2 W. The BaMS/XRF instrument would provide data on the oxidation state of iron and its distribution among iron-bearing mineralogies and elemental composition information. This data is a primary concern for the characterization of extraterrestrial surface materials.

Inflammatory responses to the occupational inhalation of metal fume.

PubMed

Palmer, K T; McNeill Love, R M C; McNeill-Love, R; Poole, J R; Coggon, D; Frew, A J; Linaker, C H; Shute, J K

2006-02-01

Occupational exposure to metal fume promotes a reversible increase in the risk of pneumonia, but by mechanisms which are unclear. To investigate, the current authors measured various markers of host defence function in welders and nonwelders. Induced sputum and venous blood samples were collected from 27 welders with regular long-term exposure to ferrous metal fume and 31 unexposed matched controls. In sputum, the present authors measured cell counts, the soluble and cellular iron concentration, and levels of interleukin-8, tumour necrosis factor-alpha, myeloperoxidase, matrix metalloproteinase-9, immunoglobulin (Ig)A, alpha(2)-macroglobulin and unsaturated iron-binding capacity. Blood samples were assayed for evidence of neutrophil activation and pneumococcal IgG antibodies. Welders had significantly higher iron levels and a substantially lower unsaturated iron-binding capacity in their sputum, but, despite a high iron challenge, there was a noteworthy absence of an inflammatory response. Only blood counts of eosinophils and basophils were significantly related to the extent of welding. Weak nonsignificant trends were observed for several other measures, consistent with low-grade priming of neutrophils. In conclusion, these data suggest that chronic exposure to metal fume blunts responsiveness to inhaled particulate matter. However, the mechanism behind the lack of detectable local inflammatory response requires further investigation.

Development of copper recovery process from flotation tailings by a combined method of high‒pressure leaching‒solvent extraction.

PubMed

Han, Baisui; Altansukh, Batnasan; Haga, Kazutoshi; Stevanović, Zoran; Jonović, Radojka; Avramović, Ljiljana; Urosević, Daniela; Takasaki, Yasushi; Masuda, Nobuyuki; Ishiyama, Daizo; Shibayama, Atsushi

2018-06-15

Sulfide copper mineral, typically Chalcopyrite (CuFeS 2 ), is one of the most common minerals for producing metallic copper via the pyrometallurgical process. Generally, flotation tailings are produced as a byproduct of flotation and still consist of un‒recovered copper. In addition, it is expected that more tailings will be produced in the coming years due to the increased exploration of low‒grade copper ores. Therefore, this research aims to develop a copper recovery process from flotation tailings using high‒pressure leaching (HPL) followed by solvent extraction. Over 94.4% copper was dissolved from the sample (CuFeS 2 as main copper mineral) by HPL in a H 2 O media in the presence of pyrite, whereas the iron was co‒dissolved with copper according to an equation given as C Cu  = 38.40 × C Fe . To avoid co‒dissolved iron giving a negative effect on the subsequent process of electrowinning, solvent extraction was conducted on the pregnant leach solution for improving copper concentration. The result showed that 91.3% copper was recovered in a stripped solution and 98.6% iron was removed under the optimal extraction conditions. As a result, 86.2% of copper was recovered from the concentrate of flotation tailings by a proposed HPL‒solvent extraction process. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Mechanochemical and Roasting Techniques for Extraction of Rare Earth Elements from Indonesian Low-Grade Bauxite

NASA Astrophysics Data System (ADS)

Kusrini, E.; Harjanto, S.; Herdino, F.; Prasetyanto, EA; Rahman, A.

2018-03-01

In this research, the extraction of lanthanides from low-grade bauxite via mechanochemical and roasting methods has been studied. The addition of NaOH during mechanochemical process significantly increased the yield of collected rare earth elements. The effect of roasting process at temperatures in the ranges from 400°C to 1100°C was analyzed. The highest recovery values of lanthanide that extracted from low-grade bauxite at various temperatures and ratio low-grade bauxite and NaOH solid, with variations in the ratio of 1: 1 and 2: 1 were obtained for yttrium (∼95.6%), lanthanum (∼79.6%), cerium (∼54.7%), neodymium (∼81.8%), and samarium (∼80.0%) from the theoretical value.

Enhanced bioremediation of oil contaminated soil by graded modified Fenton oxidation.

PubMed

Xu, Jinlan; Xin, Lei; Huang, Tinglin; Chang, Kun

2011-01-01

Graded modified Fenton's (MF) oxidation is a strategy in which H2O2 is added intermittently to prevent a sharp temperature increase and undesired soil sterilization at soil circumneutral pH versus adding the same amount of H2O2 continuously. The primary objective of the present study was to investigate whether a mild MF pre-oxidation such as a stepwise addition of H2O2 can prevent sterilization and achieve a maximum degradation of tank oil in soil. Optimization experiments of graded MF oxidation were conducted using citric acid, oxalic acid and SOLV-X as iron chelators under different frequencies of H2O2 addition. The results indicated that the activity order of iron chelates decreased as: citric acid (51%) > SOLV-X (44%) > oxalic acid (9%), and citric acid was found to be an optimized iron chelating agent of graded MF oxidation. Three-time addition of H2O2 was found to be favorable and economical due to decreasing total petroleum hydrocarbon removal from three time addition (51%) to five time addition (59%). Biological experiments were conducted after graded MF oxidation of tank oil completed under optimum conditions mentioned above. After graded oxidation, substantially higher increase (31%) in microbial activity was observed with excessive H2O2 (1470 mmol/L, the mol ratio of H2O2:Fe2+ was 210:1) than that of non-oxidized soil. Removal efficiency of tank oil was up to 93% after four weeks. Especially, the oil fraction (C10-C40) became more biodagradable after graded MF oxidation than its absence. Therefore, graded MF oxidation is a mild pretreatment to achieve an effective bioremediation of oil contaminated soil.

Oral iron supplements for children in malaria-endemic areas

PubMed Central

Neuberger, Ami; Okebe, Joseph; Yahav, Dafna; Paul, Mical

2016-01-01

Background Iron-deficiency anaemia is common during childhood. Iron administration has been claimed to increase the risk of malaria. Objectives To evaluate the effects and safety of iron supplementation, with or without folic acid, in children living in areas with hyperendemic or holoendemic malaria transmission. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library, MEDLINE (up to August 2015) and LILACS (up to February 2015). We also checked the metaRegister of Controlled Trials (mRCT) and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to February 2015. We contacted the primary investigators of all included trials, ongoing trials, and those awaiting assessment to ask for unpublished data and further trials. We scanned references of included trials, pertinent reviews, and previous meta-analyses for additional references. Selection criteria We included individually randomized controlled trials (RCTs) and cluster RCTs conducted in hyperendemic and holoendemic malaria regions or that reported on any malaria-related outcomes that included children younger than 18 years of age. We included trials that compared orally administered iron, iron with folic acid, and iron with antimalarial treatment versus placebo or no treatment. We included trials of iron supplementation or fortification interventions if they provided at least 80% of the Recommended Dietary Allowance (RDA) for prevention of anaemia by age. Antihelminthics could be administered to either group, and micronutrients had to be administered equally to both groups. Data collection and analysis The primary outcomes were clinical malaria, severe malaria, and death from any cause. We assessed the risk of bias in included trials with domain-based evaluation and assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We performed a fixed-effect meta-analysis for all outcomes and random-effects meta-analysis for hematological outcomes, and adjusted analyses for cluster RCTs. We based the subgroup analyses for anaemia at baseline, age, and malaria prevention or management services on trial-level data. Main results Thirty-five trials (31,955 children) met the inclusion criteria. Overall, iron does not cause an excess of clinical malaria (risk ratio (RR) 0.93, 95% confidence intervals (CI) 0.87 to 1.00; 14 trials, 7168 children, high quality evidence). Iron probably does not cause an excess of clinical malaria in both populations where anaemia is common and those in which anaemia is uncommon. In areas where there are prevention and management services for malaria, iron (with or without folic acid) may reduce clinical malaria (RR 0.91, 95% CI 0.84 to 0.97; seven trials, 5586 participants, low quality evidence), while in areas where such services are unavailable, iron (with or without folic acid) may increase the incidence of malaria, although the lower CIs indicate no difference (RR 1.16, 95% CI 1.02 to 1.31; nine trials, 19,086 participants, low quality evidence). Iron supplementation does not cause an excess of severe malaria (RR 0.90, 95% CI 0.81 to 0.98; 6 trials, 3421 children, high quality evidence). We did not observe any differences for deaths (control event rate 1%, low quality evidence). Iron and antimalarial treatment reduced clinical malaria (RR 0.54, 95% CI 0.43 to 0.67; three trials, 728 children, high quality evidence). Overall, iron resulted in fewer anaemic children at follow up, and the end average change in haemoglobin from base line was higher with iron. Authors' conclusions Iron treatment does not increase the risk of clinical malaria when regular malaria prevention or management services are provided. Where resources are limited, iron can be administered without screening for anaemia or for iron deficiency, as long as malaria prevention or management services are provided efficiently. PLAIN LANGUAGE SUMMARY Iron supplements for children living in malaria-endemic countries Why the review is important Children living in malarial areas commonly develop anaemia. Long-term anaemia is thought to delay a child's development and make children more likely to get infections. In areas where anaemia is common, health providers may give iron to prevent anaemia, but there is a concern amongst researchers that this may increase the risk of malaria. It is thought that the iron tablets will increase iron levels in the blood, and this will promote the growth of the Plasmodium parasite that causes malaria. We aimed to assess the effects of oral iron supplementation in children living in countries where malaria is common. Main findings of the review Cochrane researchers searched the available evidence up to 30 August 2015 and included 35 trials (31,955 children). Iron did not increase the risk of malaria, indicated by fever and the presence of parasites in the blood (high quality evidence). There was no increased risk of death among children treated with iron, although the quality of the evidence for this was low. Among children treated with iron, there was no increased risk of severe malaria (high quality evidence). Although it is hypothesized that iron supplementation might harm children who do not have anaemia living in malarial areas, there is probably no increased risk for malaria in these children (moderate quality evidence). In areas where health services are sufficient to help prevent and treat malaria, giving iron supplements (with or without folic acid) may reduce clinical malaria. In areas where these services are not available, iron supplementation (with or without folic acid) may increase the number of children with clinical malaria (low quality evidence). Overall, iron resulted in fewer anaemic children at follow up, and the end average change in haemoglobin from base line was higher with iron. Conclusions Our conclusions are that iron supplementation does not adversely affect children living in malaria-endemic areas. Based on our review, routine iron supplementation should not be withheld from children living in countries where malaria is prevalent and malaria management services are available. PMID:26921618

Serum ceruloplasmin protein expression and activity increases in iron-deficient rats and is further enhanced by higher dietary copper intake

PubMed Central

Ranganathan, Perungavur N.; Lu, Yan; Jiang, Lingli; Kim, Changae

2011-01-01

Increases in serum and liver copper content are noted during iron deficiency in mammals, suggesting that copper-dependent processes participate during iron deprivation. One point of intersection between the 2 metals is the liver-derived, multicopper ferroxidase ceruloplasmin (Cp) that is important for iron release from certain tissues. The current study sought to explore Cp expression and activity during physiologic states in which hepatic copper loading occurs (eg, iron deficiency). Weanling rats were fed control or low iron diets containing low, normal, or high copper for ∼ 5 weeks, and parameters of iron homeostasis were measured. Liver copper increased in control and iron-deficient rats fed extra copper. Hepatic Cp mRNA levels did not change; however, serum Cp protein was higher during iron deprivation and with higher copper consumption. In-gel and spectrophotometric ferroxidase and amine oxidase assays demonstrated that Cp activity was enhanced when hepatic copper loading occurred. Interestingly, liver copper levels strongly correlated with Cp protein expression and activity. These observations support the possibility that liver copper loading increases metallation of the Cp protein, leading to increased production of the holo enzyme. Moreover, this phenomenon may play an important role in the compensatory response to maintain iron homeostasis during iron deficiency. PMID:21768302

[Low level auditory skills compared to writing skills in school children attending third and fourth grade: evidence for the rapid auditory processing deficit theory?].

PubMed

Ptok, M; Meisen, R

2008-01-01

The rapid auditory processing defi-cit theory holds that impaired reading/writing skills are not caused exclusively by a cognitive deficit specific to representation and processing of speech sounds but arise due to sensory, mainly auditory, deficits. To further explore this theory we compared different measures of auditory low level skills to writing skills in school children. prospective study. School children attending third and fourth grade. just noticeable differences for intensity and frequency (JNDI, JNDF), gap detection (GD) monaural and binaural temporal order judgement (TOJb and TOJm); grade in writing, language and mathematics. correlation analysis. No relevant correlation was found between any auditory low level processing variable and writing skills. These data do not support the rapid auditory processing deficit theory.

Effect of temperature on porosity of iron ore sinter with biochar derived from EFB

NASA Astrophysics Data System (ADS)

Purwanto, H.; Rozhan, A. N.; Zakiyuddin, A.; Mohamad, A. S.

2018-01-01

In this research, the replacement of fossil fuel energy (coke) with oil palm empty fruit bunch as a potential energy in sintering of iron ore was investigated. Carbon derived biomass has been produced by using oil palm empty fruit bunch by heat treatment process. In the present investigation, sintering process was carried out by heating the mixed iron ore and biochar at various temperatures. The apparent density and porosity for iron sinter show a significant increase and gradual decrement as the temperature increase, respectively. The porosity of iron sinter shows a gradual decrement from 950 °C to 1050 °C but up to 1150 °C it shows a significant decrement about 44%. Inferring to the micrograph, the agglomeration and assimilation of sinter at high temperature is better compared with low sintering temperature.

Geology of the Eymir iron mine, Edremit, Turkey

USGS Publications Warehouse

Jacobson, Herbert Samuel; Turet, Erdogan

1972-01-01

The Eymir mine near Edremit on Turkey's Aegean coast (long 27?30'E.,1at 39?36'N.) was investigated as part of the Maden Tetkik ve Arama Enstitutsu (MTA)-U. S. Geological Survey (USGS) mineral exploration and training project, for the purpose of increasing the known mineral reserves. Geologic mapping of the mine area indicates that hematite is restricted to argillized, silicified, and pyritized dacite and possibly andesite. Hematite is present as massive replacements, impregnations, disseminations, and fracture fillings. Most of the upper part of the iron deposit consists of a breccia composed mostly of silicifiled dacite fragments in a hematite matrix. The iron deposit was apparently formed in three steps: 1. Argillation, silicification, and pyritization of the andesitic lava and dacite units as a result of a regional intrusion. 2. Intrusion of the Dere Oren dacite stock, with associated faulting, fracturing, and breccia formation at the surface. 3. Deposition of hematite by oxidation of pyrite, and transfer of iron via fractures and faults by hydrothermal or meteoric fluids. The Eymir iron deposit is a blanketlike deposit on the crest of the Sivritepe-Eymir ridge. It is 1300 meters long, 80 to 450 meters wide, and has an average thickness of 18.6 meters. Drill holes in the deposit show the iron content to range from 32.0 to 57.6 percent, and to average 46.5 percent. Most of the gangue is silica, and an arsenic impurity averaging 0.39 percent is present. Most of the deposit cannot be utilized as iron ore because of low iron content, high silica content, and high arsenic content. Ore-dressing tests have shown that it is feasible to concentrate the low-grade material, producing a concentrate having increased iron content and reduced silica content. Tests have shown also that the arsenic content of the ore can be reduced substantially by sintering. Further tests and economic feasibility studies are necessary to determine whether an economic marketable iron ore can be produced. If such studies indicate the technical and economic feasibility of utilizing all the Eymir iron deposit, detailed additional studies are recommended including: 1. A detailed drilling and sampling program to include 60 drill holes averaging 40 meters in depth and detailed sampling of mine dumps. 2. Pilot-plant testing of concentration and sintering procedures. 3. A detailed pre-investment economic feasibility study.

Multiple-micronutrient supplementation for women during pregnancy.

PubMed

Haider, Batool A; Bhutta, Zulfiqar A

2017-04-13

Multiple-micronutrient (MMN) deficiencies often coexist among women of reproductive age in low- to middle-income countries. They are exacerbated in pregnancy due to the increased demands, leading to potentially adverse effects on the mother and developing fetus. Though supplementation with MMNs has been recommended earlier because of the evidence of impact on pregnancy outcomes, a consensus is yet to be reached regarding the replacement of iron and folic acid supplementation with MMNs. Since the last update of this Cochrane review, evidence from a few large trials has recently been made available, the inclusion of which is critical to inform policy. To evaluate the benefits of oral multiple-micronutrient supplementation during pregnancy on maternal, fetal and infant health outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 March 2015) and reference lists of retrieved articles and key reviews. We also contacted experts in the field for additional and ongoing trials. All prospective randomised controlled trials evaluating MMN supplementation with iron and folic acid during pregnancy and its effects on the pregnancy outcome were eligible, irrespective of language or the publication status of the trials. We included cluster-randomised trials, but quasi-randomised trials were excluded. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach. Nineteen trials (involving 138,538 women) were identified as eligible for inclusion in this review but only 17 trials (involving 137,791 women) contributed data to the review. Fifteen of these 17 trials were carried out in low and middle-income countries and compared MMN supplements with iron and folic acid versus iron with or without folic acid. Two trials carried out in the UK compared MMN with a placebo. MMN with iron and folic acid versus iron, with or without folic acid (15 trials): MMN resulted in a significant decrease in the number of newborn infants identified as low birthweight (LBW) (average risk ratio (RR) 0.88, 95% confidence interval (CI) 0.85 to 0.91; high-quality evidence) or small-for-gestational age (SGA) (average RR 0.92, 95% CI 0.86 to 0.98; moderate-quality evidence). No significant differences were shown for other maternal and pregnancy outcomes: preterm births (average RR 0.96, 95% CI 0.90 to 1.03; high-quality evidence), stillbirth (average RR 0.97, 95% CI 0.87, 1.09; high-quality evidence), maternal anaemia in the third trimester (average RR 1.03, 95% CI 0.85 to 1.24), miscarriage (average RR 0.91, 95% CI 0.80 to 1.03), maternal mortality (average RR 0.97, 95% CI 0.63 to 1.48), perinatal mortality (average RR 1.01, 95% CI 0.91 to 1.13; high-quality evidence), neonatal mortality (average RR 1.06, 95% CI 0.92 to 1.22; high-quality evidence), or risk of delivery via a caesarean section (average RR 1.04; 95% CI 0.74 to 1.46).A number of prespecified, clinically important outcomes could not be assessed due to insufficient or non-available data. Single trials reported results for: very preterm birth < 34 weeks, macrosomia, side-effects of supplements, nutritional status of children, and congenital anomalies including neural tube defects and neurodevelopmental outcome: Bayley Scales of Infant Development (BSID) scores. None of these trials reported pre-eclampsia, placental abruption, premature rupture of membranes, cost of supplementation, and maternal well-being or satisfaction.When assessed according to GRADE criteria, the quality of evidence for the review's primary outcomes overall was good. Pooled results for primary outcomes were based on multiple trials with large sample sizes and precise estimates. The following outcomes were graded to be as of high quality: preterm birth, LBW, perinatal mortality, stillbirth and neonatal mortality. The outcome of SGA was graded to be of moderate quality, with evidence downgraded by one for funnel plot asymmetry and potential publication bias.We carried out sensitivity analysis excluding trials with high levels of sample attrition (> 20%); results were consistent with the main analysis except for the findings for SGA (average RR 0.91, 95% CI 0.84 to 1.00). We explored heterogeneity through subgroup analyses by maternal height and body mass index (BMI), timing of supplementation and dose of iron. Subgroup differences were observed for maternal BMI for the outcome preterm birth, with significant findings among women with low BMI. Subgroup differences were also observed for maternal BMI and maternal height for the outcome SGA, indicating a significant impact among women with higher maternal BMI and height. The overall analysis of perinatal mortality, although showed a non-significant effect of MMN supplements versus iron with or without folic acid, was found to have substantial statistical heterogeneity. Subgroup differences were observed for timing of supplementation for this outcome, indicating a significantly higher impact with late initiation of supplementation. The findings between subgroups for other primary outcomes were inconclusive. MMN versus placebo (two trials): A single trial in the UK found no clear differences between groups for preterm birth, SGA, LBW or maternal anaemia in the third trimester. A second trial reported the number of women with pre-eclampsia; there was no evidence of a difference between groups. Other outcomes were not reported. Our findings support the effect of MMN supplements with iron and folic acid in improving some birth outcomes. Overall, pregnant women who received MMN supplementation had fewer low birthweight babies and small-for-gestational-age babies. The findings, consistently observed in several systematic evaluations of evidence, provide a basis to guide the replacement of iron and folic acid with MMN supplements containing iron and folic acid for pregnant women in low and middle-income countries where MMN deficiencies are common among women of reproductive age. Efforts could focus on the integration of this intervention in maternal nutrition and antenatal care programs in low and middle-income countries.

Sulfur and iron accumulation in three marine-archaeological shipwrecks in the Baltic Sea: The Ghost, the Crown and the Sword

NASA Astrophysics Data System (ADS)

Fors, Yvonne; Grudd, Håkan; Rindby, Anders; Jalilehvand, Farideh; Sandström, Magnus; Cato, Ingemar; Bornmalm, Lennart

2014-02-01

Sulfur and iron concentrations in wood from three 17th century shipwrecks in the Baltic Sea, the Ghost wreck, the Crown and the Sword, were obtained by X-ray fluorescence (XRF) scanning. In near anaerobic environments symbiotic microorganisms degrade waterlogged wood, reduce sulfate and promote accumulation of low-valent sulfur compounds, as previously found for the famous wrecks of the Vasa and Mary Rose. Sulfur K-edge X-ray absorption near-edge structure (XANES) analyses of Ghost wreck wood show that organic thiols and disulfides dominate, together with elemental sulfur probably generated by sulfur-oxidizing Beggiatoa bacteria. Iron sulfides were not detected, consistent with the relatively low iron concentration in the wood. In a museum climate with high atmospheric humidity oxidation processes, especially of iron sulfides formed in the presence of corroding iron, may induce post-conservation wood degradation. Subject to more general confirmation by further analyses no severe conservation concerns are expected for the Ghost wreck wood.

Formation of secondary minerals in a lysimeter approach - A mineral-microbe interaction

NASA Astrophysics Data System (ADS)

Schäffner, F.; Merten, D.; De Giudici, G.; Beyer, A.; Akob, D. M.; Ricci, P. C.; Küsel, K.; Büchel, G.

2012-04-01

Heavy metal contamination of large areas due to uranium mining operations poses a serious long-term environmental problem. In the Ronneburg district (eastern Thuringia, Germany), leaching of low grade uranium bearing ores (uranium content < 300 g/t) occurred from 1972 to 1990 using acid mine drainage (AMD; pH 2.7-2.8) and diluted sulphuric acid (10 g/l). Secondary mineral phases like birnessite, todorokite and goethite occur within a natural attenuation process associated with enrichment of heavy metals, especially Cd, Ni, Co, Cu and Zn due to a residual contamination even after remediation efforts. To reveal the processes of secondary mineral precipitation in the field a laboratory lysimeter approach was set up under in situ-like conditions. Homogenized soil from the field site and pure quartz sand were used as substrates. In general, in situ measurements of redox potentials in the substrates showed highly oxidizing conditions (200-750 mV). Water was supplied to the lysimeter from below via a mariottés bottle containing contaminated groundwater from the field. Evaporation processes were allowed, providing a continuous flow of water. This led to precipitation of epsomite and probably aplowite on the top layer of substrate, similar to what is observed in field investigations. After 4 weeks, the first iron and manganese bearing secondary minerals became visible. Soil water samples were used to monitor the behaviour of metals within the lysimeter. Saturation indices (SI) for different secondary minerals were calculated with PHREEQC. The SI of goethite showed oversaturation with respect to the soil solution. SEM-EDX analyses and IR spectroscopy confirmed the formation of goethite. Geochemical data revealed that goethite formation was mainly dominated by Eh/pH processes and that heavy metals, e.g. Zn and U, could be enriched in this phase. Although Eh/pH data does not support formation of manganese minerals, Mn(II)-oxidizing bacteria (MOB) could be isolated from field soil samples, supporting the fact that microorganisms may influence this natural attenuation process. Laser ablation ICP-MS data reveal accumulation of manganese in MOB biomass on Mn(II)-containing agar plates. Furthermore, it was possible to show the importance of iron on this process, as some MOB isolates were able to oxidize manganese independently from the iron content, whereas some are not. The latter isolates are only able to oxidize manganese if iron is present in the media. In the lysimeter, SEM-EDX data showed microorganisms in organic rich phases together with the occurrence of manganese, oxygen, and nickel, indicating manganese oxides enriched in nickel. Although this new mineral phases could not yet be identified microprobe EDX results from polished thin sections showed needle-like mineral structures that are similar to the birnessite and todorokite samples observed from field samples. Hence, the lysimeter experiment revealed that the formation of iron and manganese minerals that are involved in heavy metal natural attenuation is result of both abiotic and biotic processes.

Arabidopsis copper transport protein COPT2 participates in the cross talk between iron deficiency responses and low-phosphate signaling.

PubMed

Perea-García, Ana; Garcia-Molina, Antoni; Andrés-Colás, Nuria; Vera-Sirera, Francisco; Pérez-Amador, Miguel A; Puig, Sergi; Peñarrubia, Lola

2013-05-01

Copper and iron are essential micronutrients for most living organisms because they participate as cofactors in biological processes, including respiration, photosynthesis, and oxidative stress protection. In many eukaryotic organisms, including yeast (Saccharomyces cerevisiae) and mammals, copper and iron homeostases are highly interconnected; yet, such interdependence is not well established in higher plants. Here, we propose that COPT2, a high-affinity copper transport protein, functions under copper and iron deficiencies in Arabidopsis (Arabidopsis thaliana). COPT2 is a plasma membrane protein that functions in copper acquisition and distribution. Characterization of the COPT2 expression pattern indicates a synergic response to copper and iron limitation in roots. We characterized a knockout of COPT2, copt2-1, that leads to increased resistance to simultaneous copper and iron deficiencies, measured as reduced leaf chlorosis and improved maintenance of the photosynthetic apparatus. We propose that COPT2 could play a dual role under iron deficiency. First, COPT2 participates in the attenuation of copper deficiency responses driven by iron limitation, possibly to minimize further iron consumption. Second, global expression analyses of copt2-1 versus wild-type Arabidopsis plants indicate that low-phosphate responses increase in the mutant. These results open up new biotechnological approaches to fight iron deficiency in crops.

Removal of chromium from synthetic plating waste by zero-valent iron and sulfate-reducing bacteria.

PubMed

Guha, Saumyen; Bhargava, Puja

2005-01-01

Experiments were conducted to evaluate the potential of zero-valent iron and sulfate-reducing bacteria (SRB) for reduction and removal of chromium from synthetic electroplating waste. The zero-valent iron shows promising results as a reductant of hexavalent chromium (Cr+6) to trivalent chromium (Cr+3), capable of 100% reduction. The required iron concentration was a function of chromium concentration in the waste stream. Removal of Cr+3 by adsorption or precipitation on iron leads to complete removal of chromium from the waste and was a slower process than the reduction of Cr+6. Presence SRB in a completely mixed batch reactor inhibited the reduction of Cr+6. In a fixed-bed column reactor, SRB enhanced chromium removal and showed promising results for the treatment of wastes with low chromium concentrations. It is proposed that, for waste with high chromium concentration, zero-valent iron is an efficient reductant and can be used for reduction of Cr+6. For low chromium concentrations, a SRB augmented zero-valent iron and sand column is capable of removing chromium completely.

Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran) using REE geochemistry

NASA Astrophysics Data System (ADS)

Mokhtari, Mir Ali Asghar; Zadeh, Ghader Hossein; Emami, Mohamad Hashem

2013-06-01

Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE-NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle forming sub-surface injections or surface flows. These ores have formed during magmatism as immiscible liquids (silicate and Fe-P-rich magmatic liquids) which separated from strongly differentiated magmas aided by a large volatile and alkali element content. Separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits. We proposed that the separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits.

Prostate cancer outcome and tissue levels of metal ions

USGS Publications Warehouse

Sarafanov, A.G.; Todorov, T.I.; Centeno, J.A.; MacIas, V.; Gao, W.; Liang, W.-M.; Beam, C.; Gray, Marion A.; Kajdacsy-Balla, A.

2011-01-01

BACKGROUNDThere are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome.METHODSWe obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case–control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se.RESULTSPatients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 µg/g vs. 111 µg/g; P = 0.04) and 21% lower zinc (279 µg/g vs. 346 µg/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 µg/g vs. 0.439 µg/g; 4% higher) and selenium (1.68 µg/g vs. 1.58 µg/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively).CONCLUSIONSThere is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. 

Discrimination of iron ore deposits of granulite terrain of Southern Peninsular India using ASTER data

NASA Astrophysics Data System (ADS)

Rajendran, Sankaran; Thirunavukkarasu, A.; Balamurugan, G.; Shankar, K.

2011-04-01

This work describes a new image processing technique for discriminating iron ores (magnetite quartzite deposits) and associated lithology in high-grade granulite region of Salem, Southern Peninsular India using visible, near-infrared and short wave infrared reflectance data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Image spectra show that the magnetite quartzite and associated lithology of garnetiferrous pyroxene granulite, hornblende biotite gneiss, amphibolite, dunite, and pegmatite have absorption features around spectral bands 1, 3, 5, and 7. ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in RGB are constructed by summing the bands representing the shoulders of absorption features as a numerator, and the band located nearest the absorption feature as a denominator to map iron ores and band ratios ((2 + 4)/3, (5 + 7)/6, (7 + 9)/8) in RGB for associated lithology. The results show that ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in a Red-Green-Blue (RGB) color combination identifies the iron ores much better than previously published ASTER band ratios analysis. A Principal Component Analysis (PCA) is applied to reduce redundant information in highly correlated bands. PCA (3, 2, and 1 for iron ores and 5, 4, 2 for granulite rock) in RGB enabled the discrimination between the iron ores and garnetiferrous pyroxene granulite rock. Thus, this image processing technique is very much suitable for discriminating the different types of rocks of granulite region. As outcome of the present work, the geology map of Salem region is provided based on the interpretation of ASTER image results and field verification work. It is recommended that the proposed methods have great potential for mapping of iron ores and associated lithology of granulite region with similar rock units of granulite regions of Southern Peninsular India. This work also demonstrates the ability of ASTER's to provide information on iron ores, which is valuable for mineral prospecting and exploration activities.

Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature

NASA Astrophysics Data System (ADS)

Han, Hongliang; Duan, Dongping; Chen, Siming; Yuan, Peng

2015-10-01

In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 °C and 1200 °C). When the temperature is above 1473 K (1200 °C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 °C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 °C and 1300 °C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 °C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.

Pilot scale application of nanosized iron oxides as electron acceptors for bioremediation

NASA Astrophysics Data System (ADS)

Bosch, Julian; Fritzsche, Andreas; Frank-Fahle, Beatrice; Lüders, Tilmann; Höss, Sebastian; Eisenmann, Heinrich; Held, Thomas; Totsche, Kai U.; Meckenstock, Rainer U.

2014-05-01

Microbial reduction of ferric iron is a major biogeochemical process in groundwater aquifer ecosystems and often associated with the degradation of organic contaminants, as bacteria couple iron reduction to the oxidation reduced carbon like e.g. BTEX. Yet in general the low bioavailability of natural iron oxides limits microbial reduction rates. However, nanosized iron oxides have an unequally enhanced bioavailability and reactivity compared to their respective bulk, macro-sized, and more crystalline materials. At the same time, nanosized iron oxides can be produced in stable colloidal suspensions, permitting efficient injections into contaminated aquifers. We examined the reactivity of nanosized synthetic colloidal iron oxides in microbial iron reduction. Application of colloidal nanoparticles led to a strong and sustainable enhancement of microbial reaction rates in batch experiments and sediment columns. Toluene oxidation was increased five-fold as compared to bulk, non-colloidal ferrihydrite as electron acceptor. Furthermore, we developed a unique approach for custom-tailoring the subsurface mobility of these particles after being injected into a contaminant plume. In a field pilot application, we injected 18 m3 of an iron oxide nanoparticle solution into a BTEX contaminated aquifer with a maximum excess pressure as low as 0.2 bar. The applied suspension showed a superior subsurface mobility, creating a reactive zone of 4 m height (corresponding to the height of the confined aquifer) and 6 m in diameter. Subsequent monitoring of BTEX, microbial BTEX degradation metabolites, ferrous iron generation, stable isotopes fractionation, microbial populations, and methanogenesis demonstrated the strong impact of our approach. Mathematic processed X-ray diffractograms and FTIR spectra provided a semi-quantitatively estimate of the long-term fate of the iron oxide colloids in the aquifer. Potential environmental risks of the injection itself were monitored with ecotoxicological investigations. Our data suggest that the injection of ferric iron nanoparticles as electron acceptors into contaminated aquifers for the enhancement of microbial contaminant degradation might develop into a novel bioremediation strategy.

Hydrogen Plasma Processing of Iron Ore

NASA Astrophysics Data System (ADS)

Sabat, Kali Charan; Murphy, Anthony B.

2017-06-01

Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

Appraisal of iron deposits in southern and western Turkey

USGS Publications Warehouse

Gair, Jacob Eugene; Capan, Ussal Z.

1972-01-01

Between May 20 and June 17, 1969, previously known iron deposits were examined widely at eight separate localities in western Turkey. The object of the examinations was to learn the, nature, geologic setting, and approximate size of each deposit, to review prior estimates of size, and possibly recommend additional exploratory work.. The full extent of each deposit is poorly known at the present time, so recommended additional work entails drilling, digging trenches or pits, geologic mapping or, combinations of these activities. On Qaldagi Mountain an area of about 1 sq km is capped by bredciated chert under which may be a continuous zone of mixed iron oxides and chert fragments. The thickness of the ferruginous zone is poorly known but is as much as 12 meters, in at least one place. The- ferruginous material and chert appear to have formed by the weathering of serpentine, bun this concept needs further testing. Drilling is recommended to determine the grade, thickness, and extent-of the ferruginous zone beneath the cherty cap. Inasmuch as mining by hand sorting is in progress, part of the deposit can be considered to be marginally in the category of iron reserves. The Keceborlu iron deposit consists of earthy to slightly compacted hematite and limonite mixed with small chert fragments. The surface area underlain by ferruginous rock is about 5,000 to 7,500 sq meters. The maximum known thickness of the deposit is about 7 meters. Iron appears to have been concentrated by weathering and oxidation of cherty limestone. The deposit is probably either a remnant of a once more extensive weathered cap, or a sink hole filling. The Keceborlu area warrants a low priority for further exploration, but one drill hole is recommended to test the thickness of the deposit. The iron deposits at Mellec are layered and vein-magnetite replacements of limestone. The six known deposits are discontinuous. No additional. work is recommended. ' The Gilindire Iron deposit consists of irregular concentrations of pisolitic and earthy hematite and 'limonite along an unconformity or disconformity between two groups of limestone. The ferruginous zone is incompletely known around the rim of the large Gilindire syncline. Data from trenches 5 to 6 km around the syncline--about ? the possible length of the ferruginous zone--provide the main knowledge about the size and grade of ferruginous lenses. The ferruginous lenses range in thickness from a fraction of a meter, to about 3 meters, but appear to average 1 meter or less, and range in grade from about 10 to 37 percent iron. No additional exploration work is recommended at Gilindire. The Buyukeceli deposit consists of veinlike masses of earthy and compact hematite and limonite cutting fresh limestone. The veins apparently originally contained siderite which has been weathered and converted to iron oxide. Further exploration by drilling is recommended at such time as other largest deposits are able to be brought into the development stage in the Mediterranean coastal area of Turkey. The iron deposits overlooking Bayas on the Gulf of Iskenderun ere in one or more layers along the west-facing front of the Amanus Mountain Range, between beds of gently to moderately east-dipping limestone. Isolated exposures may represent a once-continuous ferruginous bed that has been blockfaulted and intruded by serpentine. The ferruginous bed (or beds) is 20-30 meters thick, and consists of a mixture of very fine grained hematite and claylike material. Iron content ranges from 20 to 40 percent and aluminum, averages about 15 percent. Available data on distribution are scant but suggest that one ferruginous bed may be 1-2 kilometers long, 500 meters wide and 20 meters thick. The potentially large size of the Payas deposits warrants an early coordinated program of drilling end beneficiation testing. An iron deposit was examined on a conspicuous limestone ridge in the Syrian graben east of the Amanus Moun

The effect of feeding a low iron diet prior to and during gestation on fetal and maternal iron homeostasis in two strains of rat

PubMed Central

2013-01-01

Background Iron deficiency anaemia during pregnancy is a global problem, with short and long term consequences for maternal and child health. Animal models have demonstrated that the developing fetus is vulnerable to maternal iron restriction, impacting on postnatal metabolic and blood pressure regulation. Whilst long-term outcomes are similar across different models, the commonality in mechanistic events across models is unknown. This study examined the impact of iron deficiency on maternal and fetal iron homeostasis in two strains of rat. Methods Wistar (n=20) and Rowett Hooded Lister (RHL, n=19) rats were fed a control or low iron diet for 4 weeks prior to and during pregnancy. Tissues were collected at day 21 of gestation for analysis of iron content and mRNA/protein expression of regulatory proteins and transporters. Results A reduction in maternal liver iron content in response to the low iron diet was associated with upregulation of transferrin receptor expression and a reduction in hepcidin expression in the liver of both strains, which would be expected to promote increased iron absorption across the gut and increased turnover of iron in the liver. Placental expression of transferrin and DMT1+IRE were also upregulated, indicating adaptive responses to ensure availability of iron to the fetus. There were considerable differences in hepatic maternal and fetal iron content between strains. The higher quantity of iron present in livers from Wistar rats was not explained by differences in expression of intestinal iron transporters, and may instead reflect greater materno-fetal transfer in RHL rats as indicated by increased expression of placental iron transporters in this strain. Conclusions Our findings demonstrate substantial differences in iron homeostasis between two strains of rat during pregnancy, with variable impact of iron deficiency on the fetus. Whilst common developmental processes and pathways have been observed across different models of nutrient restriction during pregnancy, this study demonstrates differences in maternal adaptation which may impact on the trajectory of the programmed response. PMID:23635304

Multiple-micronutrient supplementation for women during pregnancy.

PubMed

Haider, Batool A; Bhutta, Zulfiqar A

2015-11-01

Multiple-micronutrient (MMN) deficiencies often coexist among women of reproductive age in low- to middle-income countries. They are exacerbated in pregnancy due to the increased demands, leading to potentially adverse effects on the mother and developing fetus. Though supplementation with MMNs has been recommended earlier because of the evidence of impact on pregnancy outcomes, a consensus is yet to be reached regarding the replacement of iron and folic acid supplementation with MMNs. Since the last update of this Cochrane review, evidence from a few large trials has recently been made available, the inclusion of which is critical to inform policy. To evaluate the benefits of oral multiple-micronutrient supplementation during pregnancy on maternal, fetal and infant health outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (11 March 2015) and reference lists of retrieved articles and key reviews. We also contacted experts in the field for additional and ongoing trials. All prospective randomised controlled trials evaluating MMN supplementation during pregnancy and its effects on the pregnancy outcome were eligible, irrespective of language or the publication status of the trials. We included cluster-randomised trials, but quasi-randomised trials were excluded. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach. Nineteen trials (involving 138,538 women) were identified as eligible for inclusion in this review but only 17 trials (involving 137,791 women) contributed data to the review. Fifteen of these 17 trials were carried out in low and middle-income countries and compared MMN supplements with iron and folic acid versus iron with or without folic acid. Two trials carried out in the UK compared MMN with a placebo. MMN with iron and folic acid versus iron, with or without folic acid (15 trials): MMN resulted in a significant decrease in the number of newborn infants identified as low birthweight (LBW) (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.85 to 0.91; high-quality evidence) or small-for-gestational age (SGA) (average RR 0.90, 95% CI 0.83 to 0.97; moderate-quality evidence), and a reduced rate of stillbirth (RR 0.91, 95% CI 0.85 to 0.98; high-quality evidence). No significant differences were shown for other maternal and pregnancy outcomes: preterm births (RR 0.96, 95% CI 0.89 to 1.03; high-quality evidence), maternal anaemia in the third trimester (RR 0.97, 95% CI 0.86 to 1.10), miscarriage (RR 0.89, 95% CI 0.78 to 1.01), maternal mortality (RR 0.97, 95% CI 0.63 to 1.48), perinatal mortality (RR 0.97, 95% CI 0.84 to 1.12; high-quality evidence), neonatal mortality (RR 0.98, 95% CI 0.90 to 1.07; high -quality evidence), or risk of delivery via a caesarean section (RR 1.03; 95% CI 0.75 to 1.43).A number of prespecified, clinically important outcomes could not be assessed due to insufficient or non-available data. Single trials reported results for: very preterm birth < 34 weeks, macrosomia, side-effects of supplements, nutritional status of children, and congenital anomalies including neural tube defects and neurodevelopmental outcome: Bayley Scales of Infant Development (BSID) scores. None of these trials reported pre-eclampsia, placental abruption, premature rupture of membranes, cost of supplementation, and maternal well-being or satisfaction.When assessed according to GRADE criteria, the quality of evidence for the review's primary outcomes overall was good. Pooled results for primary outcomes were based on multiple trials with large sample sizes and precise estimates. The following outcomes were graded to be as of high quality: preterm birth, LBW, perinatal mortality, stillbirth and neonatal mortality. The outcome of SGA was graded to be of moderate quality, with evidence downgraded by one for funnel plot asymmetry and potential publication bias.We carried out sensitivity analysis excluding trials with high levels of sample attrition (> 20%); results were consistent with the main analysis. We explored heterogeneity through subgroup analysis by maternal height and body mass index (BMI), timing of supplementation and dose of iron. Subgroup differences were observed for maternal BMI and timing of supplementation for the outcome preterm birth, with significant findings among women with low BMI and with earlier initiation of supplementation in the prenatal period. Subgroup differences were also observed for maternal BMI, maternal height and dose of iron for the outcome SGA, indicating a significant impact among women with higher maternal BMI and height, and with MMN supplement containing 30 mg of iron versus control receiving 60 mg of iron. The findings between subgroups for other primary outcomes were inconclusive. MMN versus placebo (two trials): A single trial in the UK found no clear differences between groups for preterm birth, SGA, LBW or maternal anaemia in the third trimester. A second trial reported the number of women with pre-eclampsia; there was no evidence of a difference between groups. Other outcomes were not reported. Our findings support the effect of MMN supplements with iron and folic acid in improving birth outcomes. The findings, consistently observed in several systematic evaluations of evidence, provide a strong basis to guide the replacement of iron and folic acid with MMN supplements containing iron and folic acid for pregnant women in developing countries where MMN deficiencies are common among women of reproductive age. Efforts should be focused on the integration of this intervention in maternal nutrition and antenatal care programs in developing countries.

Removal of iron and manganese using biological roughing up flow filtration technology.

PubMed

Pacini, Virginia Alejandra; María Ingallinella, Ana; Sanguinetti, Graciela

2005-11-01

The removal of iron and manganese from groundwater using biological treatment methods is almost unknown in Latin America. Biological systems used in Europe are based on the process of double rapid biofiltration during which dissolved oxygen and pH need to be strictly controlled in order to limit abiotic iron oxidation. The performance of roughing filter technology in a biological treatment process for the removal of iron and manganese, without the use of chemical agents and under natural pH conditions was studied. Two pilot plants, using two different natural groundwaters, were operated with the following treatment line: aeration, up flow roughing filtration and final filtration (either slow or rapid). Iron and manganese removal efficiencies were found to be between 85% and 95%. The high solid retention capability of the roughing filter means that it is possible to remove iron and manganese simultaneously by biotic and abiotic mechanisms. This system combines simple, low-cost operation and maintenance with high iron and manganese removal efficiencies, thus constituting a technology which is particularly suited to small waterworks.

Sliding wear and corrosion behaviour of alloyed austempered ductile iron subjected to novel two step austempering treatment

NASA Astrophysics Data System (ADS)

Sethuram, D.; Srisailam, Shravani; Rao Ponangi, Babu

2018-04-01

Austempered Ductile Iron(ADI) is an exciting alloy of iron which offers the design engineers the best combination high strength-to-weight ratio, low cost design flexibility, good toughness, wear resistance along with fatigue strength. The two step austempering procedure helps in simultaneously improving the tensile strength as-well as the ductility to more than that of the conventional austempering process. Extensive literature survey reveals that it’s mechanical and wear behaviour are dependent on heat treatment and alloy additions. Current work focuses on characterizing the two-step ADI samples (TSADI) developed by novel heat treatment process for resistance to corrosion and wear. The samples of Ductile Iron were austempered by the two-Step Austempering process at temperatures 300°C to 450°C in the steps of 50°C.Temperaturesare gradually increased at the rate of 14°C/Hour. In acidic medium (H2SO4), the austempered samples showed better corrosive resistance compared to conventional ductile iron. It has been observed from the wear studies that TSADI sample at 350°C is showing better wear resistance compared to ductile iron. The results are discussed in terms of fractographs, process variables and microstructural features of TSADI samples.

Beneficiation of Kulon Progo iron sand by using tabling and magnetic separation methods

NASA Astrophysics Data System (ADS)

Oediyani, Soesaptri; Ikhlasul Amal, M.; M. Victoriyan, N.; Juniarsih, Andinnie

2018-04-01

There are two types of iron resources such as primary iron ore and iron sand. In general, primary iron ores use as raw materials in iron and steel making because the iron content is high (± 60%) and can reduce directly. On the other and, iron sand is rarely used as a raw material because the iron content is low (20-40%) but the iron sand reserves are very abundant in Indonesia for instance is about 173 million tons in Kulon Progo, Jogyakarta. In addition, the new regulation of Energy and Mineral Resources Ministry required that iron sands must process before are being export. Therefore, the proper beneficiation methods are need to improve the iron content of iron sand. In this research Kulon Progo iron sand was used as a raw materials because not only the reserves very abundant but also the new iron making plant will build here soon. The combine of ore concentration methods such as tabling and magnetic separation used to improve the iron content. Then, the variable process were inclination of the table (2°,3° and 4°), fraction of feed size (-100 mesh, -150 mesh and -200 mesh) and the magnetic intensity (176, 830, 1500 Gauss). The highest recovery was about 96.75% and the concentrate which is contain 59.78 % Fe achieved by using -200 mesh particle size, 4° inclination of table and 1500 Gauss as a magnetic intensity. In conclusion, this concentrate fulfilled raw material requires of iron making (≥ 55%Fe).

Iron, phytoplankton growth, and the carbon cycle.

PubMed

Street, Joseph H; Paytan, Adina

2005-01-01

Iron is an essential nutrient for all living organisms. Iron is required for the synthesis of chlorophyll and of several photosynthetic electron transport proteins and for the reduction of CO2, SO4(2-), and NO3(-) during the photosynthetic production of organic compounds. Iron concentrations in vast areas of the ocean are very low (<1 nM) due to the low solubility of iron in oxic seawater. Low iron concentrations have been shown to limit primary production rates, biomass accumulation, and ecosystem structure in a variety of open-ocean environments, including the equatorial Pacific, the subarctic Pacific and the Southern Ocean and even in some coastal areas. Oceanic primary production, the transfer of carbon dioxide into organic carbon by photosynthetic plankton (phytoplankton), is one process by which atmospheric CO2 can be transferred to the deep ocean and sequestered for long periods of time. Accordingly, iron limitation of primary producers likely plays a major role in the global carbon cycle. It has been suggested that variations in oceanic primary productivity, spurred by changes in the deposition of iron in atmospheric dust, control atmospheric CO2 concentrations, and hence global climate, over glacial-interglacial timescales. A contemporary application of this "iron hypothesis" promotes the large-scale iron fertilization of ocean regions as a means of enhancing the ability of the ocean to store anthropogenic CO2 and mitigate 21st century climate change. Recent in situ iron enrichment experiments in the HNLC regions, however, cast doubt on the efficacy and advisability of iron fertilization schemes. The experiments have confirmed the role of iron in regulating primary productivity, but resulted in only small carbon export fluxes to the depths necessary for long-term sequestration. Above all, these experiments and other studies of iron biogeochemistry over the last two decades have begun to illustrate the great complexity of the ocean system. Attempts to engineer this system are likely to provoke a similarly complex, unpredictable response.

Advanced zirconia-coated carbonyl-iron particles for acidic magnetorheological finishing of chemical-vapor-deposited ZnS and other IR materials

NASA Astrophysics Data System (ADS)

Salzman, S.; Giannechini, L. J.; Romanofsky, H. J.; Golini, N.; Taylor, B.; Jacobs, S. D.; Lambropoulos, J. C.

2015-10-01

We present a modified version of zirconia-coated carbonyl-iron (CI) particles that were invented at the University of Rochester in 2008. The amount of zirconia on the coating is increased to further protect the iron particles from corrosion when introduced to an acidic environment. Five low-pH, magnetorheological (MR) fluids were made with five acids: acetic, hydrochloric, nitric, phosphoric, and hydrofluoric. All fluids were based on the modified zirconia-coated CI particles. Off-line viscosity and pH stability were measured for all acidic MR fluids to determine the ideal fluid composition for acidic MR finishing of chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and other infrared (IR) optical materials, such as hot-isostatic-pressed (HIP) ZnS, CVD zinc selenide (ZnSe), and magnesium fluoride (MgF2). Results show significant reduction in surface artifacts (millimeter-size, pebble-like structures on the finished surface) for several standard-grade CVD ZnS substrates and good surface roughness for the non-CVD MgF2 substrate when MR finished with our advanced acidic MR fluid.

Mauritania.

PubMed

1987-10-01

The West African country of Mauritania bridges the chasm between Mediterranean and sub-Saharan Africa. The population of 1.85 million is a mixture of Arab, Berber and Negroid races, with languages and cultures to match, but they all share the Islam religion. Geographically, Mauritania meets Saharan Algeria on the northeast, contains mineral and iron rich hills in the center, Sahelian plains in the south, and the Senegal river valley on its southwestern border. Although a large proportion of the population are nomads, since 1980 many have settled in urban shanty-towns to escape drought. The infant mortality rate is 102/1000, life expectancy 46 years, literacy 17%, and per capita income $450. THe economy is split between those doing subsistence herding or farming, and the industrial iron and copper mines and fisheries. Mauritania has been governed by a military junta, the Committee for National Salvation, since 1978. The current government permitted municipal elections in 1986, but political parties and debate are banned. The economy is buttressed by high-grade iron ore exports; otherwise, drought, mismanagement and low commodity prices have plagued Mauritania's development.

mTOR Regulates Cellular Iron Homeostasis through Tristetraprolin

PubMed Central

Bayeva, Marina; Khechaduri, Arineh; Puig, Sergi; Chang, Hsiang-Chun; Patial, Sonika; Blackshear, Perry J.; Ardehali, Hossein

2013-01-01

SUMMARY Iron is an essential cofactor with unique redox properties. Iron regulatory proteins 1 and 2 (IRP1/2) have been established as important regulators of cellular iron homeostasis, but little is known about the role of other pathways in this process. Here we report that the mammalian target of rapamycin (mTOR) regulates iron homeostasis by modulating transferrin receptor 1 (TfR1) stability and altering cellular iron flux. Mechanistic studies identify tristetraprolin (TTP), a protein involved in anti-inflammatory response, as the downstream target of mTOR that binds to and enhances degradation of TfR1 mRNA. We also show that TTP is strongly induced by iron chelation, promotes downregulation of iron-requiring genes in both mammalian and yeast cells, and modulates survival in low-iron states. Taken together, our data uncover a link between metabolic, inflammatory, and iron regulatory pathways, and point towards the existence of a yeast-like TTP-mediated iron conservation program in mammals. PMID:23102618

Laser surface texturing of cast iron steel: dramatic edge burr reduction and high speed process optimisation for industrial production using DPSS picosecond lasers

NASA Astrophysics Data System (ADS)

Bruneel, David; Kearsley, Andrew; Karnakis, Dimitris

2015-07-01

In this work we present picosecond DPSS laser surface texturing optimisation of automotive grade cast iron steel. This application attracts great interest, particularly in the automotive industry, to reduce friction between moving piston parts in car engines, in order to decrease fuel consumption. This is accomplished by partially covering with swallow microgrooves the inner surface of a piston liner and is currently a production process adopting much longer pulse (microsecond) DPSS lasers. Lubricated interface conditions of moving parts require from the laser process to produce a very strictly controlled surface topography around the laser formed grooves, whose edge burr height must be lower than 100 nm. To achieve such a strict tolerance, laser machining of cast iron steel was investigated using an infrared DPSS picosecond laser (10ps duration) with an output power of 16W and a repetition rate of 200 kHz. The ultrashort laser is believed to provide a much better thermal management of the etching process. All studies presented here were performed on flat samples in ambient air but the process is transferrable to cylindrical geometry engine liners. We will show that reducing significantly the edge burr below an acceptable limit for lubricated engine production is possible using such lasers and remarkably the process window lies at very high irradiated fluences much higher that the single pulse ablation threshold. This detailed experimental work highlights the close relationship between the optimised laser irradiation conditions as well as the process strategy with the final size of the undesirable edge burrs. The optimised process conditions are compatible with an industrial production process and show the potential for removing extra post)processing steps (honing, etc) of cylinder liners on the manufacturing line saving time and cost.

Construction-grade plywood from grade 3 Appalachian oak

Treesearch

E. Paul Craft; E. Paul Craft

1970-01-01

In an effort to find a use for a large volume of the low-grade oak logs of Appalachia, we processed a sample of these logs in a typical southern-pine sheathing plant and determined the feasibility of converting them into construction grade plywood.

Intercritical heat treatments in ductile iron and steel

NASA Astrophysics Data System (ADS)

Aristizabal, Ricardo E.

Materials such as dual phase (DP) steels, transformation induced plasticity (TRIP) steels and dual phase ductile irons are produced by intercritical heat treatments. These materials can provide significant weight savings in the automotive industry. The goal of this dissertation is to study intercritical heat treatments in ductile iron and steel to optimize the production parameters. Three different aspects were addressed. First, common steels were intercritically austenitized and austempered (intercritically austempered) under a variety conditions. The results showed that common grade steels that were intercritically austempered exhibited tensile properties in the same range as DP and TRIP steels. The second study consisted of determining the effect of heat treatment conditions on the tensile properties of intercritically austenitized, quenched and tempered ductile iron (IAQ&TDI). The results showed that (1) ultimate tensile strength (UTS) and yield strength (YS) were determined by the volume fraction of martensite, (2) tempering improved the elongation 1.7-2.5 times with only a slight decrease in strength, (3) the carbon in austenite formed during the intercritical heat treatment of ductile iron with a ferritic-pearlitic matrix came from the carbon available in the matrix and that carbon diffusion from the graphite nodules was restricted, and (4) limited segregation of substitutional elements occurred during intercritical austenitizing. Finally, intercritically austempered ductile iron (IADI) alloyed with different amounts of manganese and nickel was produced. Tensile properties and microstructure were determined. Also, the stability of the austenite during deformation and the lattice strains of the ferrite and the austenite phases were determined using x-ray diffraction (XRD) and neutron diffraction. The results indicated that: 1) high manganese concentrations produced materials with large blocky, low carbon austenite particles at the intercellular boundaries which decreased the elongation of the materials and transformed to martensite during deformation at low strains. 2) Nickel and nickel-manganese alloys formed a combination of blocky and plate-like austenite particles, which were more stable during deformation and either transformed to martensite after yielding or did not transform at all.

Lower serum hepcidin and greater parenchymal iron in nonalcoholic fatty liver disease patients with C282Y HFE mutations

PubMed Central

Nelson, James E.; Brunt, Elizabeth M.; Kowdley, Kris V.

2012-01-01

Hepcidin regulation is linked to both iron and inflammatory signals and may influence iron loading in nonalcoholic steatohepatitis (NASH). The aim of this study was to examine the relationships among HFE genotype, serum hepcidin level, hepatic iron deposition and histology in nonalcoholic fatty liver disease (NAFLD). SNP genotyping for C282Y (rs1800562) and H63D (rs1799945) HFE mutations was performed in 786 adult subjects in the NASH Clinical Research Network (CRN). Clinical, histologic, and laboratory data were compared using nonparametric statistics and multivariate logistic regression. NAFLD patients with C282Y, but not H63D mutations, had lower median serum hepcidin levels (57 vs 65 ng/ml, p=0.01) and higher mean hepatocellular (HC) iron grades (0.59 vs 0.28, p<0.001), compared to wild type (WT) subjects. Subjects with hepatic iron deposition had higher serum hepcidin levels than subjects without iron for all HFE genotypes (p<0.0001). Hepcidin levels were highest among patients with mixed HC/reticuloendothelial system cell (RES) iron deposition. H63D mutations were associated with higher steatosis grades and NAFLD activity scores (OR≥1.4, CI >1.0≤2.5, p≤0.041), compared to WT, but not with either HC or RES iron. NAFLD patients with C282Y mutations had less ballooning or NASH (OR ≤0.62, 95% CI >0.39<0.94, p≤0.024) compared to WT subjects. Conclusions Presence of C282Y mutations in patients with NAFLD is associated with greater HC iron deposition and decreased serum hepcidin levels and there is a positive relationship between hepatic iron stores and serum hepcidin level across all HFE genotypes. These data suggest that body iron stores are the major determinant of hepcidin regulation in NAFLD regardless of HFE genotype. A potential role for H63D mutations in NAFLD pathogenesis is possible through iron-independent mechanisms. PMID:22611049

Low-temperature nitridation of manganese and iron oxides using NaNH2 molten salt.

PubMed

Miura, Akira; Takei, Takahiro; Kumada, Nobuhiro

2013-10-21

Manganese and iron nitrides are important functional materials, but their synthesis processes from oxides often require high temperatures. Herein, we show a novel meta-synthesis method for manganese and iron nitrides by low-temperature nitridation of their oxides using NaNH2 molten salt as the nitrogen source in an autoclave at 240 °C. With this method, nitridation of micrometer-sized oxide particles kept their initial morphologies, but the size of the primary particles decreased. The thermodynamic driving force is considered to be the conversion of oxides to sodium hydroxide, and the kinetic of nitridation is improved by the decrease of particle size and the low melting point of NaNH2. This technique as developed here has the advantages of low reaction temperature, reduced consumption of ammonia, employing nonspecialized equipment, and providing facile control of the reactions for producing nitrides from oxides.

Fatigue of Austempered Ductile Iron with Two Strength Grades in Very High Cycle Regime

NASA Astrophysics Data System (ADS)

Zhang, Jiwang; Li, Wei; Song, Qingpeng; Zhang, Ning; Lu, Liantao

2016-03-01

In this study, Austempered ductile irons (ADIs) with two different strength grades were produced and the fatigue properties were measured at 109 cycles. The results show that the S-N curves give a typical step-wise shape and there is no fatigue limit in the very high cycle fatigue regime. The two grades ADI have the similar fracture behaviors and fatigue failure can initiate from defects at specimen surface and subsurface zone. On the fracture surfaces of some specimens, the `granular-bright-facet' area with rich carbon distribution is observed in the vicinity of the defect. The microstructure affects the crack behaviors at the early propagation stage. The ADI with upper and lower bainite shows higher fatigue strength compared with the ADI with coarse upper bainite.

Arabidopsis Copper Transport Protein COPT2 Participates in the Cross Talk between Iron Deficiency Responses and Low-Phosphate Signaling1[C][W

PubMed Central

Perea-García, Ana; Garcia-Molina, Antoni; Andrés-Colás, Nuria; Vera-Sirera, Francisco; Pérez-Amador, Miguel A.; Puig, Sergi; Peñarrubia, Lola

2013-01-01

Copper and iron are essential micronutrients for most living organisms because they participate as cofactors in biological processes, including respiration, photosynthesis, and oxidative stress protection. In many eukaryotic organisms, including yeast (Saccharomyces cerevisiae) and mammals, copper and iron homeostases are highly interconnected; yet, such interdependence is not well established in higher plants. Here, we propose that COPT2, a high-affinity copper transport protein, functions under copper and iron deficiencies in Arabidopsis (Arabidopsis thaliana). COPT2 is a plasma membrane protein that functions in copper acquisition and distribution. Characterization of the COPT2 expression pattern indicates a synergic response to copper and iron limitation in roots. We characterized a knockout of COPT2, copt2-1, that leads to increased resistance to simultaneous copper and iron deficiencies, measured as reduced leaf chlorosis and improved maintenance of the photosynthetic apparatus. We propose that COPT2 could play a dual role under iron deficiency. First, COPT2 participates in the attenuation of copper deficiency responses driven by iron limitation, possibly to minimize further iron consumption. Second, global expression analyses of copt2-1 versus wild-type Arabidopsis plants indicate that low-phosphate responses increase in the mutant. These results open up new biotechnological approaches to fight iron deficiency in crops. PMID:23487432

The Phosphoinositide 3-Kinase Regulates Retrograde Trafficking of the Iron Permease CgFtr1 and Iron Homeostasis in Candida glabrata*

PubMed Central

Sharma, Vandana; Purushotham, Rajaram; Kaur, Rupinder

2016-01-01

The phosphoinositide 3-kinase (PI3K), which phosphorylates phosphatidylinositol and produces PI3P, has been implicated in protein trafficking, intracellular survival, and virulence in the pathogenic yeast Candida glabrata. Here, we demonstrate PI3-kinase (CgVps34) to be essential for maintenance of cellular iron homeostasis. We examine how CgVps34 regulates the fundamental process of iron acquisition, and underscore its function in vesicular trafficking as a central determinant. RNA sequencing analysis revealed iron homeostasis genes to be differentially expressed upon CgVps34 disruption. Consistently, the Cgvps34Δ mutant displayed growth attenuation in low- and high-iron media, increased intracellular iron content, elevated mitochondrial aconitase activity, impaired biofilm formation, and extenuated mouse organ colonization potential. Furthermore, we demonstrate for the first time that C. glabrata cells respond to iron limitation by expressing the iron permease CgFtr1 primarily on the cell membrane, and to iron excess via internalization of the plasma membrane-localized CgFtr1 to the vacuole. Our data show that CgVps34 is essential for the latter process. We also report that macrophage-internalized C. glabrata cells express CgFtr1 on the cell membrane indicative of an iron-restricted macrophage internal milieu, and Cgvps34Δ cells display better survival in iron-enriched medium-cultured macrophages. Overall, our data reveal the centrality of PI3K signaling in iron metabolism and host colonization. PMID:27729452

Adsorptive removal of arsenic by novel iron/olivine composite: Insights into preparation and adsorption process by response surface methodology and artificial neural network.

PubMed

Ghosal, Partha S; Kattil, Krishna V; Yadav, Manoj K; Gupta, Ashok K

2018-03-01

Olivine, a low-cost natural material, impregnated with iron is introduced in the adsorptive removal of arsenic. A wet impregnation method and subsequent calcination were employed for the preparation of iron/olivine composite. The major preparation process parameter, viz., iron loading and calcination temperature were optimized through the response surface methodology coupled with a factorial design. A significant variation of adsorption capacity of arsenic (measured as total arsenic), i.e., 63.15 to 310.85 mg/kg for arsenite [As(III) T ] and 76.46 to 329.72 mg/kg for arsenate [As(V) T ] was observed, which exhibited the significant effect of the preparation process parameters on the adsorption potential. The iron loading delineated the optima at central points, whereas a monotonous decreasing trend of adsorption capacity for both the As(III) T and As(V) T was observed with the increasing calcination temperature. The variation of adsorption capacity with the increased iron loading is more at lower calcination temperature showing the interactive effect between the factors. The adsorbent prepared at the optimized condition of iron loading and calcination temperature, i.e., 10% and 200 °C, effectively removed the As(III) T and As(V) T by more than 96 and 99%, respectively. The material characterization of the adsorbent showed the formation of the iron compound in the olivine and increase in specific surface area to the tune of 10 multifold compared to the base material, which is conducive to the enhancement of the adsorption capacity. An artificial neural network was applied for the multivariate optimization of the adsorption process from the experimental data of the univariate optimization study and the optimized model showed low values of error functions and high R 2 values of more than 0.99 for As(III) T and As(V) T . The adsorption isotherm and kinetics followed Langmuir model and pseudo second order model, respectively demonstrating the chemisorption in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antiferromagnetic Spin Coupling between Rare Earth Adatoms and Iron Islands Probed by Spin-Polarized Tunneling

PubMed Central

Coffey, David; Diez-Ferrer, José Luis; Serrate, David; Ciria, Miguel; Fuente, César de la; Arnaudas, José Ignacio

2015-01-01

High-density magnetic storage or quantum computing could be achieved using small magnets with large magnetic anisotropy, a requirement that rare-earth iron alloys fulfill in bulk. This compelling property demands a thorough investigation of the magnetism in low dimensional rare-earth iron structures. Here, we report on the magnetic coupling between 4f single atoms and a 3d magnetic nanoisland. Thulium and lutetium adatoms deposited on iron monolayer islands pseudomorphically grown on W(110) have been investigated at low temperature with scanning tunneling microscopy and spectroscopy. The spin-polarized current indicates that both kind of adatoms have in-plane magnetic moments, which couple antiferromagnetically with their underlying iron islands. Our first-principles calculations explain the observed behavior, predicting an antiparallel coupling of the induced 5d electrons magnetic moment of the lanthanides with the 3d magnetic moment of iron, as well as their in-plane orientation, and pointing to a non-contribution of 4f electrons to the spin-polarized tunneling processes in rare earths. PMID:26333417

U-shaped curve for risk associated with maternal hemoglobin, iron status, or iron supplementation.

PubMed

Dewey, Kathryn G; Oaks, Brietta M

2017-12-01

Both iron deficiency (ID) and excess can lead to impaired health status. There is substantial evidence of a U-shaped curve between the risk of adverse birth outcomes and maternal hemoglobin concentrations during pregnancy; however, it is unclear whether those relations are attributable to conditions of low and high iron status or to other mechanisms. We summarized current evidence from human studies regarding the association between birth outcomes and maternal hemoglobin concentrations or iron status. We also reviewed effects of iron supplementation on birth outcomes among women at low risk of ID and the potential mechanisms for adverse effects of high iron status during pregnancy. Overall, we confirmed a U-shaped curve for the risk of adverse birth outcomes with maternal hemoglobin concentrations, but the relations differ by trimester. For low hemoglobin concentrations, the link with adverse outcomes is more evident when hemoglobin concentrations are measured in early pregnancy. These relations generally became weaker or nonexistent when hemoglobin concentrations are measured in the second or third trimesters. Associations between high hemoglobin concentration and adverse birth outcomes are evident in all 3 trimesters but evidence is mixed. There is less evidence for the associations between maternal iron status and adverse birth outcomes. Most studies used serum ferritin (SF) concentrations as the indicator of iron status, which makes the interpretation of results challenging because SF concentrations increase in response to inflammation or infection. The effect of iron supplementation during pregnancy may depend on initial iron status. There are several mechanisms through which high iron status during pregnancy may have adverse effects on birth outcomes, including oxidative stress, increased blood viscosity, and impaired systemic response to inflammation and infection. Research is needed to understand the biological processes that underlie the U-shaped curves seen in observational studies. Reevaluation of cutoffs for hemoglobin concentrations and indicators of iron status during pregnancy is also needed. © 2017 American Society for Nutrition.

Some observations on the fracture of austempered ductile iron

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

Fan, Z.K.; Smallman, R.E.

1994-07-15

There is extensive work on the fracture of steel with ferrite or/and austenite structure, but little on crack propagation in austempered ductile iron (ADI) whose microstructure also comprises austenite and ferrite (in the form of bainitic ferrite) but with graphite nodules in the matrix. Because of its good combination of wear resistance and toughness, and its low density and low cost (compared with forge steel), ADI has been widely used for various kinds of engineering components, such as gears, crankshafts, vehicle components, sprockets, cutting and digging tools etc. The matrix of ADI can withstand a certain amount of deformation beforemore » fracture during tensile or impact testing; for example, the elongation of ADI (grade 1050/700/7 to ASTM Standard) can reach 7--10% during tensile testing. However, the graphite nodules in the matrix cannot deform and hence are barriers to matrix deformation and give rise to crack initiation. In addition, carbides may precipitate in the bainitic ferrite laths or at the ferrite/austenite interfaces and these may also influence the fracture of ADI and produce characteristic features.« less

Compacted graphite iron: Cast iron makes a comeback

NASA Astrophysics Data System (ADS)

Dawson, S.

1994-08-01

Although compacted graphite iron has been known for more than four decades, the absence of a reliable mass-production technique has resulted in relatively little effort to exploit its operational benefits. However, a proven on-line process control technology developed by SinterCast allows for series production of complex components in high-quality CGI. The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. Concurrent with these primary benefits, CGI also provides significant emissions and fuel efficiency benefits allowing automakers to meet legislated performance standards. The operational and environmental benefits of compacted graphite iron together with its low cost and recyclability reinforce cast iron as a prime engineering material for the future.

Nano- and microstructural disperse rocks in protective barriers, medicine and balneology

NASA Astrophysics Data System (ADS)

Panko, A. V.; Kovzun, I. G.; Prokopenko, V. A.; Tsyganovich, O. A.; Oliinyk, V. O.; Nikipelova, O. M.

2018-03-01

On the base of results of electron microscopy, thermogravimetric, X-ray, rheological, mechanochemical and medico-biological research methods, there are proposed models of physico-mechanical, nanochemical, colloidal and biocolloid metamorphic processes of iron oxide-silicate rocks, which are accompanied by formation of nano- and microdispersed pelitic sediments, peloids (therapeutic muds), clays, sedimentary iron-silicate-carbonate ore materials. The role of microorganisms and surface-active products of their vital activity in these processes is shown. It was noted that a stable existence of ecosystems, which contain iron oxide-hydroxide-silicate polymineral formations, is largely determined by preliminary processes of geomechanical dispersion of rocks and by subsequent processes of vital activity of various microorganisms. The metabolic products of such microorganisms activate the biocolloid interactions, which are due to cooperative colloidal, biological, biochemical and nanochemical transformations of biogeocenosis of living and non-living substance. The conceptions of role and meaning of chemical and biocolloidal processes of iron and silicon nanocluster formation are developed for strength changes in contact zones of microparticles in polymineral dispersion systems which, respectively, have an influence on their rheological properties. It is shown that in the presence of sodium chloride (seawater, lake's brine) for low-iron clay-sand systems, a dilatant-thixotropic nature of the flow is observed, and at a high-iron content in the form of nanostructured goethite, a hypernomalous growth of concentrated iron-silicate suspensions' viscosity and enhancement of contact interactions in them are observed. Taking into account the established phenomena the application of iron oxide-silicate peloid compositions in the construction of protective barriers, in medicine and balneology (treatment of injured joints, wounds, leukemia, etc.) is considered.

Dephosphorization of High-Phosphorus Iron Ore Using Different Sources of Aspergillus niger Strains.

PubMed

Xiao, Chunqiao; Wu, Xiaoyan; Chi, Ruan

2015-05-01

High-phosphorus iron ore is traditionally dephosphorized by chemical process with inorganic acids. However, this process is not recommended nowadays because of its high cost and consequent environmental pollution. With the current tendency for development of a low-cost and eco-friendly process, dephosphorization of high-phosphorus iron ore through microbial process with three different sources of Aspergillus niger strains was studied in this study. Results show that the three strains of A. niger could grow well in the broth, and effectively remove phosphate from high-phosphorus iron ore during the experiments. Meanwhile, the total iron in the broth was also increased. Acidification of the broth seemed to be the major mechanism for the dephosphorization by these strains. High-pressure liquid chromatography analysis indicated that various organic acids were secreted in the broth, which caused a significant drop of the broth pH. Scanning electron microscopy of ore residues revealed that the high-phosphorus iron ore was obviously destroyed by the actions of these strains. Ore residues by energy-dispersive X-ray microanalysis and Fourier transform infrared spectroscopy indicated that the phosphate was obviously removed from the high-phosphorus iron ore. The optimization of the dephosphorization by these strains was also investigated, and the maximum percentages of phosphate removal were recorded at temperature 27-30 °C, initial pH 5.0-6.5, particle size 0.07-0.1 mm, and pulp density of 2-3% (w/v), respectively. The fungus A. niger was found to have good potential for the dephosphorization of high-phosphorus iron ore, and this microbial process seems to be economic and effective in the future industrial application.

Exploring the Role of Conventionality in Children's Interpretation of Ironic Remarks

ERIC Educational Resources Information Center

Burnett, Debra L.

2015-01-01

Irony comprehension in seven- and eight-year-old children with typically developing language skills was explored under the framework of the graded salience hypothesis. Target ironic remarks, either conventional or novel/situation-specific, were presented following brief story contexts. Children's responses to comprehension questions were used to…

Descriptive and grade-tonnage models of volcanogenic manganese deposits in oceanic environments; a modification

USGS Publications Warehouse

Mosier, Dan L.; Page, Norman J

1988-01-01

Four types of volcanogenic manganese deposits, distinguished on the basis of geologic, geochemical, and geophysical characteristics, appear to result from a combination of volcanic and hydrothermal processes related to hot-spring activity in oceanic environments. We compare these four desposit types, here called the Franciscan, Cuban, Olympic Peninsula, and Cyprus, with respect to host rocks, associated rocks, minerals, deposit shape, dimensions, volume, tonnage, grade, and mineral-deposit density (number of deposits per unit area). Franciscan-type deposits occur in obducted oceanic ridge and backarc marginal-basin environments, are associated with chert, shale, and graywacke aroun the margins of mafic volcanic centers, and have a median tonnage of 450 t and median grades of 36 weight percent Mn and less than 5.1 weight percent Fe. Cuban-type deposits occur in island-arc environments, are associated with tuff and limestone around domal structures or intrusions inferred to be volcanic centers, and have a median tonnage of 6,400 t and median grades of 39 weight percent Mn and less than 4.4 weight percent Fe. Olympic Peninsula-type deposits occur in obducted oceanic midplate settings, are associated with argillaceous limestone, argillite, and graywacke around mafic volcanic centers (seamounts or islands), and have a median tonnage of 340 t and median grades of 35 weight percent Mn and less than 6.5 weight percent Fe. Cyprus-type deposits occur in the same tectonic environments as Franciscan type but are associated with basalt, marl, chalk, silt, and chert off the ridge-axis position and have a median tonnage of 41,000 t and median grades of 33 weight percent Fe and 8 weight percent Mn. All these deposits are thin ellipsoids, concordant to the host rocks, but Cyprus-and Cuban-type deposits are larger than Franciscan- and Olympic Peninsula-type deposits. Except for Cyprus-type deposits, which are manganiferous iron (umber) deposits composed of hydrated iron and manganese oxides, all volcanogenic manganese deposits contain manganese oxides, silicates, and carbonates. Mineral-deposit densities, along with grade and tonnage information, are useful for estimating the number, size, andgrades of these deposits in resource assessments.

Impacts on water quality and biota from natural acid rock drainage in Colorado's Lake Creek watershed

USGS Publications Warehouse

Bird, D.A.; Sares, Matthew A.; Policky, Greg A.; Schmidt, Travis S.; Church, Stan E.

2006-01-01

Colorado's Lake Creek watershed hosts natural acid rock drainage that significantly impacts surface water, streambed sediment, and aquatic life. The source of the ARD is a group of iron-rich springs that emerge from intensely hydrothermally altered, unexploited, low-grade porphyry copper mineralization in the Grizzly Peak Caldera. Source water chemistry includes pH of 2.5 and dissolved metal concentrations of up to 277 mg/L aluminum, 498 mg/L iron, and 10 mg/L copper. From the hydrothermally altered area downstream for 27 kilometers to Twin Lakes Reservoir, metal concentrations in streambed sediment are elevated and the watershed experiences locally severe adverse impacts to aquatic life due to the acidic, metal-laden water. The water and sediment quality of Twin Lakes Reservoir is sufficiently improved that the reservoir supports a trout fishery, and remnants of upstream ARD are negligible.

Drinking water and biofilm disinfection by Fenton-like reaction.

PubMed

Gosselin, F; Madeira, L M; Juhna, T; Block, J C

2013-10-01

A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Environmental Effects on the Metallicities of Early-Type Galaxies

NASA Technical Reports Server (NTRS)

Jones, Christine; Oliversen, Ronald (Technical Monitor)

2004-01-01

We completed and published two papers in the Astrophysical Journal based on research from grant. In the first paper we analyzed nine X-ray-bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profiles and abundances of Mg, Si, and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of cooler regions at the galaxies' centers. We present new evidence for iron abundance gradients in NGC 4472 and NGC 4649 and confirm the previous results on NGC 4636. Mg and Si abundance gradients on average are flatter than those of iron and correspond to an underabundance of α-process elements at high Fe values, while at low iron the element ratios favor enrichment by Type II supernovae (SNe). We explain the observed trend using the metallicity dependence of SN Ia metal production and present constraints on the available theoretical modeling for low-metallicity inhibition of SNe Ia. In the second paper We analyzed nine X-ray-bright Virgo early-type galaxies observed by both ASCA and ROSAT. Through spatially resolved spectroscopy, we determined the radial temperature profiles and abundances of Mg, Si, and Fe for six galaxies. The temperature profiles are consistent with isothermal temperatures outside of cooler regions at the galaxies' centers. We present new evidence for iron abundance gradients in NGC 4472 and NGC 4649 and confirm the previous results on NGC 4636. Mg and Si abundance gradients on average are flatter than those of iron and correspond to an underabundance of α-process elements at high Fe values, while at low iron the element ratios favor enrichment by Type I1 supernovae (SNe). We explain the observed trend using the metallicity dependence of SN Ia metal production and present constraints on the available theoretical modeling for low-metallicity inhibition of SNe Ia.

Redox process catalysed by growing crystal-strengite, FePO4,2H2O, crystallizing from solution with iron(II) and hydroxylamine

NASA Astrophysics Data System (ADS)

Lundager Madsen, Hans Erik

2014-09-01

In an attempt to grow pure crystals of the iron(II) phosphate vivianite, Fe3(PO4)2,8H2O, from a solution of Mohr's salt, Fe(NH4)2(SO4)2,6H2O, added to a solution of ammonium phosphate, hydroxylammonium chloride, NH3OHCl, was added to the iron(II) stock solution to eliminate oxidation of iron(II) by oxygen from the air. However, the effect turned out to be the opposite of the expected: whereas hydroxylamine reduces iron(III) in bulk solution, it acted as a strong oxidant in the presence of growing iron phosphate crystals, causing the crystallization of the iron(III) phosphate strengite, FePO4,2H2O, as the only solid phase. Evidently the crystal surface catalyses oxidation of iron(II) by hydroxylamine. The usual composite kinetics of spiral growth and surface nucleation was found. The surface-nucleation part yielded edge free energy λ in the range 12-45 pJ/m, virtually independent of temperature and in the range typical for phosphates of divalent metals. The scatter of values for λ presumably arises from contributions from different crystal forms to the overall growth rate. The low mean value points to strong adsorption of iron(II), which is subsequently oxidized at the crystal surface, forming strengite. The state of the system did not tend to thermodynamic equilibrium, but to a metastable state, presumably controlled by the iron(II) rich surface layer of the crystal. In addition to crystal growth, it was possible to measure nucleation kinetics by light scattering (turbidimetry). A point of transition from heterogeneous to homogeneous nucleation was found, and from the results for the homogeneous domain a rather precise value of crystal surface free energy γ=55 mJ/m2 was found. This is a relatively low value as well, indicating that the redox process plays a role already at the nucleation stage.

Trapped Melt in IIIAB Irons: Solid/Liquid Elemental Partitioning During the Fractionation of the IIIAB Magma

NASA Technical Reports Server (NTRS)

Wasson, John T.

1999-01-01

Group IIIAB, the largest iron-meteorite group, shows compositional trends (including a three-order-of-magnitude It concentration range) indicating that it formed by fractional crystallization of a metallic magma. Because about 200 irons are available, and all degrees of crystallization are well represented, IIIAB offers an excellent set of samples for the study of crystallization at all depths of the asteroidal core. On log-log Ir-Au, and Ir-As diagrams IIIAB forms a broad band; the breadth represents real meteorite-to-meteorite variations, far outside experimental or sampling uncertainties. A successful model must explain the width of this band; I suggest that it mainly resulted from the trapping of parental magma within the crystallizing solid. Because S is essentially insoluble in metal, the abundance of FeS is a measure of the fraction of trapped liquid. The trapped-melt model is supported by the observation that irons having higher S contents plot closer to the inferred composition of the magmatic parental liquid. The lowest S values are found in the irons occupying the left envelope of the IIIAB Ir-Au or Ir-As compositional fields, thus it is this set of irons that should be interpreted as the solid products of a fractionating magma. This simplifies the modeling of the crystallization process and allows inferences regarding the distribution ratios for other elements in the evolved IIIAB system. The large (multiton) Cape York irons show wide variations in their trapped-melt fractions; their compositions seem best understood in terms of a low initial S content of the IIIAB magma, about 20 mg/g. The inferred initial IIIAB distribution coefficient for Ir, 4.6, is much higher than published values based on laboratory studies of low-S systems; I suggest that low-S (and low-P) partition-ratio measurements tend to err in the direction of unity. In IIIAB distribution coefficients for Au, As, and Ni were still < 1 when the most evolved IIIAB irons formed, another indication of a low initial S content.

A Sustainable and Selective Roasting and Water-Leaching Process to Simultaneously Extract Valuable Metals from Low-Grade Ni-Cu Matte

NASA Astrophysics Data System (ADS)

Cui, Fuhui; Mu, Wenning; Wang, Shuai; Xin, Haixia; Xu, Qian; Zhai, Yuchun

2018-03-01

Due to stringent environmental requirements and the complex occurrence of valuable metals, traditional pyrometallurgical methods are unsuitable for treating low-grade nickel-copper matte. A clean and sustainable two-stage sulfating roasting and water-leaching process was used to simultaneously extract valuable metals from low-grade nickel-copper matte. Ammonium and sodium sulfate were used as sulfating agents. The first roasting temperature, mass ratio of ammonium sulfate to matte, roasting time, dosage of sodium sulfate, second roasting temperature and leaching temperature were studied. Under optimal conditions, 98.89% of Ni, 97.48% of Cu and 95.82% of Co, but only 1.34% of Fe, were extracted. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to reveal the sulfating mechanism during the roasting process.

Isolation and characterization of a novel Acidithiobacillus ferrivorans strain from the Chilean Altiplano: attachment and biofilm formation on pyrite at low temperature.

PubMed

Barahona, Sergio; Dorador, Cristina; Zhang, Ruiyong; Aguilar, Pablo; Sand, Wolfgang; Vera, Mario; Remonsellez, Francisco

2014-11-01

Microorganisms are used to aid the extraction of valuable metals from low-grade sulfide ores in mines worldwide, but relatively little is known about this process in cold environments. This study comprises a preliminary analysis of the bacterial diversity of the polyextremophilic acid River Aroma located in the Chilean Altiplano, and revealed that Betaproteobacteria was the most dominant bacterial group (Gallionella-like and Thiobacillus-like). Taxa characteristic of leaching environments, such Acidithiobacillus and Leptospirillum, were detected at low abundances. Also, bacteria not associated with extremely acidic, metal-rich environments were found. After enrichment in iron- and sulfur-oxidizing media, we isolated and identified a novel psychrotolerant Acidithiobacillus ferrivorans strain ACH. This strain can grow using ferrous iron, sulfur, thiosulfate, tetrathionate and pyrite, as energy sources. Optimal growth was observed in the presence of pyrite, where cultures reached a cell number of 6.5 · 10(7) cells mL(-1). Planktonic cells grown with pyrite showed the presence of extracellular polymeric substances (10 °C and 28 °C), and a high density of cells attached to pyrite grains were observed at 10 °C by electron microscopy. The attachment of cells to pyrite coupons and the presence of capsular polysaccharides were visualized by using epifluorescence microscopy, through nucleic acid and lectin staining with Syto(®)9 and TRITC-Con A, respectively. Interestingly, we observed high cell adhesion including the formation of microcolonies within 21 days of incubation at 4 °C, which was correlated with a clear induction of capsular polysaccharides production. Our data suggests that attachment to pyrite is not temperature-dependent in At. ferrivorans ACH. The results of this study highlight the potential of this novel psychrotolerant strain in oxidation and attachment to minerals under low-temperature conditions. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Ischaemic Strokes in Patients with Pulmonary Arteriovenous Malformations and Hereditary Hemorrhagic Telangiectasia: Associations with Iron Deficiency and Platelets

PubMed Central

Shovlin, Claire L.; Chamali, Basel; Santhirapala, Vatshalan; Livesey, John A.; Angus, Gillian; Manning, Richard; Laffan, Michael A.; Meek, John; Tighe, Hannah C.; Jackson, James E.

2014-01-01

Background Pulmonary first pass filtration of particles marginally exceeding ∼7 µm (the size of a red blood cell) is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke. Methodology 497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies. Principal Findings Sixty-one individuals (12.3%) had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41–63) years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00]), and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]). For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7–27 µmol/L). Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT), correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0.039/p = 0.021). Significance These data suggest that patients with compromised pulmonary capillary filtration due to pulmonary arteriovenous malformations are at increased risk of ischaemic stroke if they are iron deficient, and that mechanisms are likely to include enhanced aggregation of circulating platelets. PMID:24586400

Comprehensive Utilization of Iron and Phosphorus from High-Phosphorus Refractory Iron Ore

NASA Astrophysics Data System (ADS)

Sun, Yongsheng; Zhang, Qi; Han, Yuexin; Gao, Peng; Li, Guofeng

2018-02-01

An innovative process of coal-based reduction followed by magnetic separation and dephosphorization was developed to simultaneously recover iron and phosphorus from one typical high-phosphorus refractory iron ore. The experimental results showed that the iron minerals in iron ore were reduced to metallic iron during the coal-based reduction and the phosphorus was enriched in the metallic iron phase. The CaO-SiO2-FeO-Al2O3 slag system was used in the dephosphorization of metallic iron. A hot metal of 99.17% Fe and 0.10% P was produced with Fe recovery of 84.41%. Meanwhile, a dephosphorization slag of 5.72% P was obtained with P recovery of 67.23%. The contents of impurities in hot metal were very low, and it could be used as feedstock for steelmaking after a secondary refining. Phosphorus in the dephosphorization slag mainly existed in the form of a 5CaO·P2O5·SiO2 solid solution where the P2O5 content is 13.10%. At a slag particle size of 20.7 μm (90% passing), 94.54% of the P2O5 could be solubilized in citric acid, indicating the slag met the feedstock requirements in phosphate fertilizer production. Consequently, the proposed process achieved simultaneous Fe and P recovery, paving the way to comprehensive utilization of high-phosphorus refractory iron ore.

Sulfur and iron geochemistry of the dynamic sedimentary system at the Costa Rica margin, IODP Expedition 344

NASA Astrophysics Data System (ADS)

Gott, C.; Riedinger, N.; Formolo, M.; Solomon, E. A.; Torres, M. E.; Bates, S. M.; Lyons, T. W.; 344 Scientific Party, I.

2013-12-01

One of the major targets of the CRISP (Costa Rica Seismogenesis Project) was to explore diagenetic processes, including fluid flow, related to the complex sedimentary and tectonic behavior of the Costa Rica margin system. Here we present preliminary results of the iron and sulfur geochemistry from sediments collected during the IODP Expedition 344 at Holes U1413B and U1414A. Our specific goal was to investigate the impact of this dynamic system on biogeochemical processes - especially regarding the sulfur cycle - and how minerals record these processes in the geologic record. The sediments at both investigated locations display non-steady state pore water conditions. Specifically, the deposits at Hole U1413B are characterized by a shallow sulfate-methane transition zone (SMTZ; approximately 15 mbsf), where released hydrogen sulfide reacts with reactive iron minerals to form iron sulfides. At Hole U1414A pore water sulfate is present at several hundreds of meters sediment depth, while the concentration of hydrogen sulfide is low (<4 μM). The measured concentrations of solid phase iron sulfides in the sediments indicate that pyrite is the main sulfur-bearing phase, reaching concentrations of 2 and 3 wt.%, in U1413B and U1414A, respectively. Sequential extractions of iron oxides reveal the presence of reactive iron phases, although in low concentrations (total iron oxides are below 1.1 wt.%), indicating ongoing alteration of iron oxides. The occurrence of these reactive iron minerals in the deeply buried sediments at Hole U1414A has implications for the deep biosphere - as those minerals can still be utilized by the microbial community. The non-steady state condition of the sedimentary system at both locations is also mirrored in the S-isotopic signal in the pore fluids as well as solid phase. The 34S-enriched sulfate (δ34S >+60 ‰) in the deeper sediment column is reflected in the δ34S profile of the in situ formed iron sulfides - the results can have implications for the interpretation of ancient rocks from similar active systems throughout Earth's history. Comparing the results of the investigated sediments at both sites, our data show variability, which may be caused by different sulfur sources and biogeochemical sulfur cycling driven by the tectonic and sedimentary complexity of the Costa Rica margin system.

Process for forming unusually strong joints between metals and ceramics by brazing at temperatures that do not exceed 750/sup 0/C

DOEpatents

Hammond, J.P.; David, S.A.; Woodhouse, J.J.

1984-12-04

This invention is a process for joining metals to ceramics to form very strong bonds using low brazing temperature, i.e., less than 750/sup 0/C, and particularly for joining nodular cast iron to partially stabilized zirconia. The process provides that the ceramic be coated with an active metal, such as titanium, that can form an intermetallic with a low melting point brazing alloy such as 60Ag-30Cu-10Sn. The nodular cast iron is coated with a noncarbon containing metal, such as copper, to prevent carbon in the nodular cast iron from dissolving in the brazing alloy. These coated surfaces can be brazed together with the brazing alloy between at less than 750/sup 0/C to form a very strong joint. An even stronger bond can be formed if a transition piece is used between the metal and ceramic. It is preferred for the transition piece to have a coefficient of thermal expansion compatible with the coefficient of thermal expansion of the ceramic, such as titanium.

Process for forming unusually strong joints between metals and ceramics by brazing at temperatures that do no exceed 750 degree C.

DOEpatents

Hammond, Joseph P.; David, Stan A.; Woodhouse, John J.

1986-01-01

This invention is a process for joining metals to ceramics to form very strong bonds using low brazing temperature, i.e., less than 750.degree. C., and particularly for joining nodular cast iron to partially stabilized zirconia. The process provides that the ceramic be coated with an active metal, such as titanium, that can form an intermetallic with a low melting point brazing alloy such as 60Ag-30Cu-10Sn. The nodular cast iron is coated with a noncarbon containing metal, such as copper, to prevent carbon in the nodular cast iron from dissolving in the brazing alloy. These coated surfaces can be brazed together with the brazing alloy between at less than 750.degree. C. to form a very strong joint. An even stronger bond can be formed if a transition piece is used between the metal and ceramic. It is preferred for the transition piece to have a coefficient of thermal compatible with the coefficient of thermal expansion of the ceramic, such as titanium.

Geology and mineral deposits of the Hekimhan-Hasancelebi iron district, Turkey

USGS Publications Warehouse

Jacobson, Herbert S.; Kendiro'glu, Zeki; ,; Celil, Bogaz; ,; Onder, Osman; Gurel, Nafis

1972-01-01

An area of 210 sq km was investigated in the Hekimhan-Hasancelebi district. of central Turkey as part of the Maden Tetkik ve Arama Institusu(MTA)-U. S. Geological Survey(USGS) mineral exploration and training project to explore for iron deposits and to provide on-.the-job training for MTA geologists. The rocks of the area are Cretaceous and Tertiary sedimentary and volcanic rocks intruded by syenite and a serpentinized mafic and ultramafic complex and overlain unconformably by late .Tertiary basalt. The base of the section is a thick mafic volcanic-sedimentary sequence with diverse rocks that include conglomerate, sandstone, shale, tuff, limestone, and basalt. The upper part of the sequence is metasomatized near syenite contacts. The sequence is conformably overlain by trachyte and unconformably overlain by massive limestone. Overlying the limestone is a Tertiary sedimentary sequence which is dominantly conglomerate and sandstone with local limestone and volcanic rocks. This series is in turn overlain by olivine basalt. Mineral deposits are associated with the two types of intrusive rocks. Hematite-magnetite in the Karakuz mine area and in the Bahcedami-Hasancelebi area is related to the syenite, and siderite in the Deveci mine area is possibly related to the mafic-ultramafic rocks. Significant iron resources are found, only in the Karakuz and Deveci areas. In the Karakuz area disseminations, veins, and replacements consisting of hematite and magnetite are present. Most of the material is low grade. In the Deveci mine area a large deposit of siderite apparently is a replacement of carbonate beds adjacent to serpentinized igneous rock. The upper part of the siderite deposit is weathered and enriched to a mixture of iron and manganese oxides of direct shipping ore grade. Additional investigation of both the Karakuz and .Deveci mine areas is recommended including: 1. A detailed gravity and magnetic survey of part of the Karakuz area. 2. Diamond drilling at both the Karakuz and Deveci areas.

Source of Chronic Inflammation in Aging.

PubMed

Sanada, Fumihiro; Taniyama, Yoshiaki; Muratsu, Jun; Otsu, Rei; Shimizu, Hideo; Rakugi, Hiromi; Morishita, Ryuichi

2018-01-01

Aging is a complex process that results from a combination of environmental, genetic, and epigenetic factors. A chronic pro-inflammatory status is a pervasive feature of aging. This chronic low-grade inflammation occurring in the absence of overt infection has been defined as "inflammaging" and represents a significant risk factor for morbidity and mortality in the elderly. The low-grade inflammation persists even after reversing pro-inflammatory stimuli such as LDL cholesterol and the renin-angiotensin system (RAS). Recently, several possible sources of chronic low-grade inflammation observed during aging and age-related diseases have been proposed. Cell senescence and dysregulation of innate immunity is one such mechanism by which persistent prolonged inflammation occurs even after the initial stimulus has been removed. Additionally, the coagulation factor that activates inflammatory signaling beyond its role in the coagulation system has been identified. This signal could be a new source of chronic inflammation and cell senescence. Here, we summarized the factors and cellular pathways/processes that are known to regulate low-grade persistent inflammation in aging and age-related disease.

Carbothermic Reduction of Nickeliferous Laterite Ores for Nickel Pig Iron Production in China: A Review

NASA Astrophysics Data System (ADS)

Rao, Mingjun; Li, Guanghui; Jiang, Tao; Luo, Jun; Zhang, Yuanbo; Fan, Xiaohui

2013-11-01

Both the consumption and production of crude stainless steel in China rank first in the world. In 2011, the nickel production in China amounted to 446 kilotons, with the proportion of electrolytic nickel and nickel pig iron (NPI) registering 41.5% and 56.5%, respectively. NPI is a low-cost feedstock for stainless steel production when used as a substitute for electrolytic nickel. The existing commercial NPI production processes such as blast furnace smelting, rotary kiln-electric furnace smelting, and Krupp-Renn (Nipon Yakin Oheyama) processes are discussed. As low-temperature (below 1300°C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500°C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

[Effect of the change in sulphate and dissolved oxygen mass concentration on metal release in old cast iron distribution pipes].

PubMed

Wu, Yong-li; Shi, Bao-you; Sun, Hui-fang; Zhang, Zhi-huan; Gu, Jun-nong; Wang, Dong-sheng

2013-09-01

To understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1). With the increase of sulfate concentration, the effluent concentrations of As, Cr, Cu, Zn and Ni also increased obviously, however, the effluent concentrations of these metals were lower than the influent concentrations under most circumstances, which indicated that adsorption of these metals by pipe corrosion scales occurred. Increasing DO within a certain range could significantly inhibit the iron release.

An image processing approach for investigation on transport of iron oxide nanoparticles (FE3O4) stabilized with poly acrylic acid in two-dimensional porous media

NASA Astrophysics Data System (ADS)

Golzar, M.; Azhdary Moghaddam, M.; Saghravani, S. F.; Dahrazma, B.

2018-04-01

Iron oxide nanoparticles were stabilized using poly acrylic acid (PAA) to yield stabilized slurry of Iron oxide nanoparticles. A two-dimensional physical model filled by glass beads was used to study the fate and transport of the iron oxide nanoparticles stabilized with PAA in porous media under saturated, steady-state flow conditions. Transport data for a nonreactive tracer, slurry of iron oxide nanoparticles stabilized with PAA were collected under similar flow conditions. The results show that low concentration slurry of iron oxide nanoparticles stabilized with PAA can be transported like a tracer without significant retardation. The image processing technique was employed to measure the tracer/nanoparticle concentration inside the 2-D model filled with glass beads. The groundwater flow model, Visual MODFLOW, was used to model the observed transport patterns through MT3DMS module. Finally, it was demonstrated that the numerical model MODFLOW can be used to predict the fate and transport characteristics of nanoparticles stabilized with PAA in groundwater aquifers.

A number of factors explain why WHO guideline developers make strong recommendations inconsistent with GRADE guidance.

PubMed

Alexander, Paul E; Gionfriddo, Michael R; Li, Shelly-Anne; Bero, Lisa; Stoltzfus, Rebecca J; Neumann, Ignacio; Brito, Juan P; Djulbegovic, Benjamin; Montori, Victor M; Norris, Susan L; Schünemann, Holger J; Thabane, Lehana; Guyatt, Gordon H

2016-02-01

Many strong recommendations issued by the World Health Organization (WHO) are based on low- or very low-quality (low certainty) evidence (discordant recommendations). Many such discordant recommendations are inconsistent with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance. We sought to understand why WHO makes discordant recommendations inconsistent with GRADE guidance. We interviewed panel members involved in guidelines approved by WHO (2007-2012) that included discordant recommendations. Interviews, recorded and transcribed, focused on use of GRADE including the reasoning underlying, and factors contributing to, discordant recommendations. Four themes emerged: strengths of GRADE, challenges and barriers to GRADE, strategies to improve GRADE application, and explanations for discordant recommendations. Reasons for discordant recommendations included skepticism about the value of making conditional recommendations; political considerations; high certainty in benefits (sometimes warranted, sometimes not) despite assessing evidence as low certainty; and concerns that conditional recommendations will be ignored. WHO panelists make discordant recommendations inconsistent with GRADE guidance for reasons that include limitations in their understanding of GRADE. Ensuring optimal application of GRADE at WHO and elsewhere likely requires selecting panelists who have a commitment to GRADE principles, additional training of panelists, and formal processes to maximize adherence to GRADE principles. Copyright © 2016 Elsevier Inc. All rights reserved.

Treatment to Destroy Chlorohydrocarbon Liquids in the Ground

NASA Technical Reports Server (NTRS)

Quinn, Jacqueline; Clausen, Christian A., III; Geiger, Cherie L.; Reinhart, Debra; Brooks, Kathleen

2003-01-01

A relatively simple chemical treatment that involves the use of emulsified iron has been found to be effective in remediating groundwater contaminated with trichloroethylene and other dense chlorohydrocarbon liquids. These liquids are members of the class of dense, nonaqueous phase liquids (DNAPLs), which are commonly recognized to be particularly troublesome as environmental contaminants. The treatment converts these liquids into less-harmful products. As a means of remediation of contaminated groundwater, this treatment takes less time and costs less than do traditional pump-and-treat processes. At some sites, long-term leakage and/or dissolution of chlorohydrocarbon liquids from pools and/or sorbed concentrations in rock and soil gives rise to a need to continue pumpand- treat processes for times as long as decades in order to maintain protection of human health and the environment. In contrast, the effects of the emulsified-iron treatment are more lasting, decreasing the need for long-term treatment and monitoring of contaminated areas. The material used in this treatment consists of iron particles with sizes of the order of nanometers to micrometers contained within the micelles of a surfactant-stabilized, biodegradable, oil-in-water emulsion. The emulsion is simple to prepare and consists of relatively inexpensive and environmentally acceptable ingredients: One typical formulation consists of 1.3 weight percent of a food-grade surfactant, 17.5 weight percent of iron particles, 23.2 weight percent of vegetable oil, and 58.0 weight percent of water.

Tungsten isotopes in bulk meteorites and their inclusions—Implications for processing of presolar components in the solar protoplanetary disk

PubMed Central

Holst, J. C.; Paton, C.; Wielandt, D.; Bizzarro, M.

2016-01-01

We present high precision, low- and high-resolution tungsten isotope measurements of iron meteorites Cape York (IIIAB), Rhine Villa (IIIE), Bendego (IC), and the IVB iron meteorites Tlacotepec, Skookum, and Weaver Mountains, as well as CI chondrite Ivuna, a CV3 chondrite refractory inclusion (CAI BE), and terrestrial standards. Our high precision tungsten isotope data show that the distribution of the rare p-process nuclide 180W is homogeneous among chondrites, iron meteorites, and the refractory inclusion. One exception to this pattern is the IVB iron meteorite group, which displays variable excesses relative to the terrestrial standard, possibly related to decay of rare 184Os. Such anomalies are not the result of analytical artifacts and cannot be caused by sampling of a protoplanetary disk characterized by p-process isotope heterogeneity. In contrast, we find that 183W is variable due to a nucleosynthetic s-process deficit/r-process excess among chondrites and iron meteorites. This variability supports the widespread nucleosynthetic s/r-process heterogeneity in the protoplanetary disk inferred from other isotope systems and we show that W and Ni isotope variability is correlated. Correlated isotope heterogeneity for elements of distinct nucleosynthetic origin (183W and 58Ni) is best explained by thermal processing in the protoplanetary disk during which thermally labile carrier phases are unmixed by vaporization thereby imparting isotope anomalies on the residual processed reservoir. PMID:27445452

The mineralogy of bauxite for producing smelter-grade alumina

NASA Astrophysics Data System (ADS)

Authier-Martin, M.; Forte, G.; Ostap, S.; See, J.

2001-12-01

Aluminum-producing companies rely on low-cost, high-purity, smelter-grade alumina (aluminum oxide), and alumina production utilizes the bulk of bauxites mined world-wide. The mineralogy of the bauxites has a significant impact on the operation of the Bayer process for alumina production. Typically, the Bayer process produces smelter-grade alumina of 99.5% Al2O3, starting from bauxite containing 30% to 60% Al2O3. The main objective of the Bayer process is to extract the maximum amount of aluminum from the bauxite at as high an aluminate concentration in solution as possible, while limiting any troublesome side reactions. Only with a better understanding of the chemistry of the mineral species and a strict control of the operating/processing conditions can the Bayer process produce efficiently, a low cost, high-quality alumina with minimum detrimental environmental impact.

Development of Grading Systems for Short-Length Lumber

Treesearch

Eugene M. Wengert; Robert W. Rice; James G. Schroeder

1987-01-01

The abundance of low grade hardwood timber and a shortage of high grade timber of many species has led to the examination of alternative processing methods for converting logs to lumber. However, present grading rules for short length lumber are not good predictors of the lumber's true value. A new method of grading short length lumber is proposed, with furniture...

Fast decolorization of azo methyl orange via heterogeneous Fenton and Fenton-like reactions using alginate-Fe2+/Fe3+ films as catalysts.

PubMed

Quadrado, Rafael F N; Fajardo, André R

2017-12-01

The efficiency of Fenton and Fenton-like processes can be seriously affected by the continuous loss of iron ions and by the formation of solid sludge. Here, alginate (Alg) films were synthesized to stabilize iron ions (Fe 2+ and Fe 3+ ) and to enhance their catalytic activities towards the decolorization of methyl orange via heterogeneous Fenton and Fenton-like processes. Iron ions were ionically bond to the Alg molecules resulting in a three-dimensional network with specific structural and morphological features according to the valence states of iron. Our results demonstrated that both Alg-Fe 2+ and Alg-Fe 3+ films show highlighted catalytic activity for the decolorization of MO and high decolorization rates. Reuse experiments demonstrated that both films could be employed in at least five consecutive decolorization processes without losing their catalytic efficiency or stability. Taken together, our findings reveal that the Alg-Fe 2+ and Alg-Fe 3+ films may be suitable low-cost catalysts in heterogeneous Fenton and Fenton-like processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Iron Overload and Chelation Therapy in Non-Transfusion Dependent Thalassemia.

PubMed

Bou-Fakhredin, Rayan; Bazarbachi, Abdul-Hamid; Chaya, Bachar; Sleiman, Joseph; Cappellini, Maria Domenica; Taher, Ali T

2017-12-20

Iron overload (IOL) due to increased intestinal iron absorption constitutes a major clinical problem in patients with non-transfusion-dependent thalassemia (NTDT), which is a cumulative process with advancing age. Current models for iron metabolism in patients with NTDT suggest that suppression of serum hepcidin leads to an increase in iron absorption and subsequent release of iron from the reticuloendothelial system, leading to depletion of macrophage iron, relatively low levels of serum ferritin, and liver iron loading. The consequences of IOL in patients with NTDT are multiple and multifactorial. Accurate and reliable methods of diagnosis and monitoring of body iron levels are essential, and the method of choice for measuring iron accumulation will depend on the patient's needs and on the available facilities. Iron chelation therapy (ICT) remains the backbone of NTDT management and is one of the most effective and practical ways of decreasing morbidity and mortality. The aim of this review is to describe the mechanism of IOL in NTDT, and the clinical complications that can develop as a result, in addition to the current and future therapeutic options available for the management of IOL in NTDT.

Method of manufacturing iron aluminide by thermomechanical processing of elemental powders

DOEpatents

Deevi, Seetharama C.; Lilly, Jr., A. Clifton; Sikka, Vinod K.; Hajaligol, Mohammed R.

2000-01-01

A powder metallurgical process of preparing iron aluminide useful as electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 20 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.05% Zr or ZrO.sub.2 stringers extending perpendicular to an exposed surface of the heating element, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B, .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1 % rare earth metal, .ltoreq.1% oxygen, and/or .ltoreq.3% Cu. The process includes forming a mixture of aluminum powder and iron powder, shaping the mixture into an article such as by cold rolling the mixture into a sheet, and sintering the article at a temperature sufficient to react the iron and aluminum powders and form iron aluminide. The sintering can be followed by hot or cold rolling to reduce porosity created during the sintering step and optional annealing steps in a vacuum or inert atmosphere.

Relationship between high- and low-grade Archean terranes: Implications for early Earth paleogeography

NASA Technical Reports Server (NTRS)

Eriksson, K. A.

1986-01-01

The Western Gneiss Terrain (WGT) of the Yilgarn Block, Western Australia was studied. The WGT forms an arcuate belt of Archean gneisses that flank the western margin of the Yilgarn Block. In general the WGT is composed of high-grade orthogneisses and paragneisses which contain supracrustal belts composed largely of siliciclastic metasediments and subordinate iron formation. The platformal nature of the metasedimentary belts and lack of obvious metavolcanic lithologies contrasts with the composition of typical Yilgarn greenstones to the east. Radiometric data from WGT rocks indicates that these rocks are significantly older than Yilgarn rocks to the east (less than 3.3 Ga) and this has led to the suggestion that the WGT represents sialic basement to Yilgarn granite-greenstone belts. The Mount Narryer region exposes the northernmost occurrence of high-grade metasediments within the WGT and consists of quartz-rich clastic metasediments at upper amphibolite to granulite grade. Most occurrences of supracrustal rocks in this region comprise isolated lenses within the gneissic basement. However, at Mount Narryer a unique sequence of metaclastics with preserved bedding provide an unusual window into the parentage of similar supracrustal bodies in this region.

Enhancing the in vitro Fe(2+) bio-accessibility using ascorbate and cold-set whey protein gel particles.

PubMed

Martin, A H; de Jong, G A H

2012-03-01

This paper investigates the possibility for iron fortification of food using a new preparation method for protein gel particles in which iron is entrapped in the presence of ascorbate using cold-set gelation. The effect of ascorbate on the iron-induced cold-set gelation process of whey protein was studied in order to optimize the ratio of iron/ascorbate. Subsequently, the effect of ascorbate on iron bio-accessibility was assessed in vitro. Rheology was used to study the protein gel formation, and the stability of the gel particles was determined by measuring the iron and protein content at different pH. In vitro studies were performed with the TNO Intestinal Model (TIM). Ascorbate appeared to affect the gel formation process and increased the gel strength of the iron-induced cold-set gels at specific iron/ascorbate ratio. With the Fe-protein gel particles being stable at a broad pH range, the release of iron from the particles was studied as a function of time. The low release of iron indicated a good encapsulation efficiency and the capability of whey protein to keep iron bound at different conditions (pH and presence of calcium). Results obtained with the TIM showed that ascorbate, when added to the protein gel particles, was very successful in enhancing the recovery and absorption of iron. The in vitro Fe(2+) bio-accessibility in the presence of ascorbate in iron-protein particles increased from 10% to almost 80%. This suggests that the concept of using protein particles with iron and ascorbate can effectively be used to fortify food products with iron for human consumption.

Optical and spectroscopic characterizations of Algerian silica raw material to predict high quality solar-grade silicon

NASA Astrophysics Data System (ADS)

Kheloufi, A.; Bobocioiu, E.; Kerkar, F.; Kefaifi, A.; Anas, S.; Medjahed, S. A.; Belkacem, Y.; Keffous, A.

2017-03-01

We assess the potential use as raw material for photovoltaics of Algerian silica samples from the quartz veins of the Tirek deposit and quartz sandstones of the Ain Barda deposit. With 97-98% purity, they all require enrichment before their industrial utilization. Acid leaching and gravimetric separation are used to remove the impurities at the grain boundaries and within the crystal lattice. We obtain course, middle, and fine products. The acid leaching process and the gravimetric separation increase the content of SiO2 up to 99.68%; the residue concentration of iron, alumina and zirconium is decreased to 70, 72 and 58 ppm respectively. These values are in agreement with requirements for silica as raw material destined for solar-grade silicon production.

Uncertainties in s -process nucleosynthesis in low mass stars determined from Monte Carlo variations

NASA Astrophysics Data System (ADS)

Cescutti, G.; Hirschi, R.; Nishimura, N.; den Hartogh, J. W.; Rauscher, T.; Murphy, A. St J.; Cristallo, S.

2018-05-01

The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have performed extensive nuclear reaction network calculations using individual and temperature-dependent uncertainties for reactions involving elements heavier than iron, within a Monte Carlo framework. Using this technique, we determined the uncertainty in the main s-process abundance predictions due to nuclear uncertainties link to weak interactions and neutron captures on elements heavier than iron. We also identified the key nuclear reactions dominating these uncertainties. We found that β-decay rate uncertainties affect only a few nuclides near s-process branchings, whereas most of the uncertainty in the final abundances is caused by uncertainties in neutron capture rates, either directly producing or destroying the nuclide of interest. Combined total nuclear uncertainties due to reactions on heavy elements are in general small (less than 50%). Three key reactions, nevertheless, stand out because they significantly affect the uncertainties of a large number of nuclides. These are 56Fe(n,γ), 64Ni(n,γ), and 138Ba(n,γ). We discuss the prospect of reducing uncertainties in the key reactions identified in this study with future experiments.

Geology of the Humboldt region and the Iron King mine, Bigbug mining district, Yavapai County, Arizona

USGS Publications Warehouse

Creasey, Saville Cyrus

1951-01-01

The Humboldt region is in central Yavapai County, Arizona. The intersection of the 112? 15' meridian and the 34? 30' N parallel is in the approximate geographical center of the region, and the Iron King mine is about 2000 feet west-northwest of the intersection. Pre-Cambrian rocks form the bedrock in the Humboldt region. Late Cenozoic unconsolidated river wash and valley fill, including some interbedded basalt, locally mantle the pre-Cambrian rocks, especially in the north-central part of the region (Lonesome Valley). The pre-Cambrian rocks consist of five newly defined metavolcanic formations derived from flows and tuff s, and of six intrusive units ranging in composition from granite to gabbro or perhaps more mafic types. Relic bedding-and pillow structures are locally prominent in the metavolcanics; geopetal structures are uncommon, but where present, generally indicate that the top is toward the west, though the evidence is too meager to be conclusive. Low-grade dynamothermal metamorphism altered the metavolcanics and to a lesser extent the intrusive rocks, forming textures, structures, and mineral assemblages characteristic of low temperature and moderate stress. The Texas Gulch formation, which is the easternmost metavolcanic formation, consists of five lithologic units. Arranged in the general order of their appearance from east to west they are meta-andesite breccia, purple slate, metarhyolite tuff, meta-andesite, and green slate. The boundary between the Texas Gulch formation and the Iron King meta-andesite is apparently gradational. The Iron King meta-andesite consists of three meta-andesite tuff units, two meta-andesite flow units and one metarhyolite tuff and conglomerate unit. The assemblage chlorite-albite-epitode with or without quartz is dominant in the meta-andesites. Mafic intrusive rocks, which may be approximately contemporaneous with metamorphism, may explain the presence of actinolitic hornblende in the central part of the formation. Toward the west the Iron King meta-andesite appears to grade into the Spud Mountain metabreccia through a zone containing beds characteristic of either one formation or the other. The Spud Mountain metabreccia consists of interbedded metabreccia and metatuff beds. The metatuffs are largely andesitic in composition, but a few thin beds of metarhyolite tuff occur. The fragments in the metabreccia beds consist chiefly or porphyritic meta-andesites and the matrix is meta-andesite tuff. Pre-Cambrian faults now marked by dikes separate the Chaparral Gulch metavolcanics, which lie west of the Spud Mountain metabreccia, from underlying and overlying formations. The Chaparral Gulch metavolcanics contain metarhyolite tuff, metarhyolite flow, and meta-andesite tuff that locally was contaminated by rhyolitic detritus. The Indian Hills metavolcanics, which are northeast of the Chaparral Gulch metavolcanics, consist of two broad units, one composed of metarhyolites and the other of meta-andesites. Metamorphosed tuffs and flows are believed to be represented in both units and flow breccia in the meta-andesites. Granite and alaskite; granodiorite and quartz diorite; diorite, mafic quartz diorite, gabbro and diabase; metarhyolite (?); and quartz porphyry comprise the pre-Cambrian intrusive units mapped. They include both deep-seated and hypabyssal types. Dynamothermal metamorphism has foliated the smaller bodies and the margins of the larger masses and partly converted them into mineral assemblages stable under low-grade metamorphic conditions. Planar structures (chiefly foliation) are omnipresent and linear structures are common in the pre-Cambrian meta-volcanic rocks. North-trending planar structures dominate in the Indian Hills metavolcanics, and in the Spud Mountain metabreccia, whereas northeast-trending planar structures are dominant in the Texas Gulch formation, Iron King meta-andesite, and Chaparral Gulch metavolcanics. To a lesser extent northeast-trending st

Therapeutic Phlebotomy is Safe in Children with Sickle Cell Anaemia and can be Effective Treatment for Transfusional Iron Overload

PubMed Central

Aygun, Banu; Mortier, Nicole A.; Kesler, Karen; Lockhart, Alexandre; Schultz, William H.; Cohen, Alan R.; Alvarez, Ofelia; Rogers, Zora R.; Kwiatkowski, Janet L.; Miller, Scott T.; Sylvestre, Pamela; Iyer, Rathi; Lane, Peter A.; Ware, Russell E.

2015-01-01

SUMMARY Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (−8.7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment. PMID:25612463

Therapeutic phlebotomy is safe in children with sickle cell anaemia and can be effective treatment for transfusional iron overload.

PubMed

Aygun, Banu; Mortier, Nicole A; Kesler, Karen; Lockhart, Alexandre; Schultz, William H; Cohen, Alan R; Alvarez, Ofelia; Rogers, Zora R; Kwiatkowski, Janet L; Miller, Scott T; Sylvestre, Pamela; Iyer, Rathi; Lane, Peter A; Ware, Russell E

2015-04-01

Serial phlebotomy was performed on sixty children with sickle cell anaemia, stroke and transfusional iron overload randomized to hydroxycarbamide in the Stroke With Transfusions Changing to Hydroxyurea trial. There were 927 phlebotomy procedures with only 33 adverse events, all of which were grade 2. Among 23 children completing 30 months of study treatment, the net iron balance was favourable (-8·7 mg Fe/kg) with significant decrease in ferritin, although liver iron concentration remained unchanged. Therapeutic phlebotomy was safe and well-tolerated, with net iron removal in most children who completed 30 months of protocol-directed treatment. © 2015 John Wiley & Sons Ltd.

Evaluation of iron aluminide weld overlays for erosion - corrosion resistant boiler tube coatings in low NO{sub x} boilers

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

DuPont, J.N.; Banovic, S.W.; Marder, A.R.

1996-08-01

Low NOx burners are being installed in many fossil fired power plants in order to comply with new Clean Air Regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion is often enhanced and premature tube failures can occur. Failures due to oxidation and solid particle erosion are also a concern. A program was initiated in early 1996 to evaluate the use of iron aluminide weld overlays for erosion/corrosion protection of boiler tubes in Low NOx boilers. Composite iron/aluminum wires will be used with the Gas Metal Arc Welding (GMAW) process to prepare overlays on boiler tubesmore » steels with aluminum contents from 8 to 16wt%. The weldability of the composite wires will be evaluated as a function of chemical composition and welding parameters. The effect of overlay composition on corrosion (oxidation and sulfidation) and solid particle erosion will also be evaluated. The laboratory studies will be complemented by field exposures of both iron aluminide weld overlays and co-extruded tubing under actual boiler conditions.« less

Weathering Grade Classification of Granite Stone Monument Using Reflectance Spectroscopy

NASA Astrophysics Data System (ADS)

Hyun, C.; Roh, T.; Choi, M.; Park, H.

2009-05-01

Stone monument has been placed in field and exposed to rain and wind. This outdoor environment and air pollution induced weathering of stone monument. Weathering grade classification is necessary to manage and conserve stone monuments. Visual interpretation by geologist and laboratory experiments using specimens fallen off from the monument to avoid damage on the monument have been applied to classify weathering grade conventionally. Rocks and minerals absorb some particular wavelength ranges of electromagnetic energy by electronic process and vibrational process of composing elements and these phenomena produce intrinsic diagnostic spectral reflectance curve. Non-destructive technique for weathering degree assessment measures those diagnostic absorption features of weathering products and converts the depths of features related to abundance of the materials to relative weathering degree. We selected granite outcrop to apply conventional six folded weathering grade classification method using Schmidt hammer rebound teste. The correlations between Schmidt hammer rebound values and absorption depths of iron oxides such as ferric oxide in the vicinity of 0.9 micrometer wavelength and clay minerals such as illite and kaolinite in the vicinity of 2.2 micrometer wavelength, representative weathering products of granite, were analyzed. The Schmidt hammer rebound value decreased according to increase of absorption depths induced from those weathering products. Weathering grade classification on the granite stone monument was conducted by using absorption depths of weathering products This research is supported from National Research Institute of Cultural Heritage and we appreciate for this.

Structural evolution of the Mount Wall region in the Hamersley province, Western Australia and its control on hydrothermal alteration and formation of high-grade iron deposits

NASA Astrophysics Data System (ADS)

Dalstra, Hilke J.

2014-10-01

The discovery of two relatively small but high-grade iron ore deposits near Mt Wall, an intensely faulted part of the southwestern Hamersley province provides unique insights into the structural control on ore formation in this region. The deposits have many geological features typical of the high grade microplaty hematite group which also contains the much larger Mt Tom Price, Paraburdoo and Mt Whaleback deposits. The deposits are structurally controlled along early normal faults and contain abundant microplaty hematite and martite, and are largely confined to the Dales Gorge member of the Brockman Iron Formation. In addition to the microplaty hematite-martite ore, there are martite-goethite ores and rare magnetite-goethite or magnetite-hematite ores. Below the modern weathering surface, hydrothermally altered zones in wallrock BIF from the Lower Dales Gorge member contain magnetite, hematite and carbonate/talc bearing mineral assemblages. A staged ore genesis model involving early extension and fluid circulation along normal faults, hypogene silica leaching and carbonate alteration, followed by deep meteoric oxidation with microplaty hematite formation and finally weathering can explain most features of the Mt Wall deposits. The role of deformation was to provide pathways for mineralising fluids and initiate the seed points for the mineralised systems. High grade iron in the Wellthandalthaluna deposit is situated between the NW to NNW trending Boolgeeda Creek fault and a synthetic joining splay, the Northern fault. Both are high angle normal faults and formed during early extension in this part of the province. Faults are characterised by localised small scale deformation and brecciation, deep carbonate alteration and oxidation. Recent weathering has penetrated deeply into the fault zones, converting the carbonate-rich assemblages into goethite. Mineralisation in the Arochar deposit is situated in the overlap or relay zone between two segments of the Mt Wall fault zone, a moderately to steeply southerly dipping normal fault system which at Arochar is intruded by dolerite dykes. At both locations, the ore controlling faults are offset by later NW trending dextral and normal faults. Fault relay zones or fault splay zones were likely zones of increased permeability and fluid flow during fault development or reactivation and may also have been important in initiating mineralisation in larger deposits such as Mt Tom Price and Mt Whaleback. However structural controls on the largest iron ore deposits are often obscured due to the intensity and scale of ore development, whereas they are better preserved in the smaller deposits. Recognition that carbonate bearing protores at Mt Wall survived for nearly two billion years until intense recent weathering converted them to martite-goethite or magnetite-goethite ores may imply that more of the giant hematite-goethite deposits of the Hamersley province had hydrothermal precursors and were not formed by supergene processes alone.

Lower serum hepcidin and greater parenchymal iron in nonalcoholic fatty liver disease patients with C282Y HFE mutations.

PubMed

Nelson, James E; Brunt, Elizabeth M; Kowdley, Kris V

2012-11-01

Hepcidin regulation is linked to both iron and inflammatory signals and may influence iron loading in nonalcoholic steatohepatitis (NASH). The aim of this study was to examine the relationships among HFE genotype, serum hepcidin level, hepatic iron deposition, and histology in nonalcoholic fatty liver disease (NAFLD). Single-nucleotide polymorphism genotyping for C282Y (rs1800562) and H63D (rs1799945) HFE mutations was performed in 786 adult subjects in the NASH Clinical Research Network (CRN). Clinical, histologic, and laboratory data were compared using nonparametric statistics and multivariate logistic regression. NAFLD patients with C282Y, but not H63D mutations, had lower median serum hepcidin levels (57 versus 65 ng/mL; P = 0.01) and higher mean hepatocellular (HC) iron grades (0.59 versus 0.28; P < 0.001), compared to wild-type (WT) subjects. Subjects with hepatic iron deposition had higher serum hepcidin levels than subjects without iron for all HFE genotypes (P < 0.0001). Hepcidin levels were highest among patients with mixed HC/reticuloendothelial system cell (RES) iron deposition. H63D mutations were associated with higher steatosis grades and NAFLD activity scores (odds ratio [OR], ≥1.4; 95% confidence interval [CI]: >1.0, ≤2.5; P ≤ 0.041), compared to WT, but not with either HC or RES iron. NAFLD patients with C282Y mutations had less ballooning or NASH (OR, ≤0.62; 95% CI: >0.39, <0.94; P ≤ 0.024), compared to WT subjects. The presence of C282Y mutations in patients with NAFLD is associated with greater HC iron deposition and decreased serum hepcidin levels, and there is a positive relationship between hepatic iron stores and serum hepcidin level across all HFE genotypes. These data suggest that body iron stores are the major determinant of hepcidin regulation in NAFLD, regardless of HFE genotype. A potential role for H63D mutations in NAFLD pathogenesis is possible through iron-independent mechanisms. Copyright © 2012 American Association for the Study of Liver Diseases.

Emission mechanisms in stabilized iron-passivated porous silicon: Temperature and laser power dependences

NASA Astrophysics Data System (ADS)

Rahmani, M.; Moadhen, A.; Mabrouk Kamkoum, A.; Zaïbi, M.-A.; Chtourou, R.; Haji, L.; Oueslati, M.

2012-02-01

Photoluminescence (PL) measurements of porous silicon (PS) and iron-porous silicon nanocomposites (PS/Fe) with stable optical properties versus temperature and laser power density have been investigated. The presence of iron in PS matrix is confirmed by Raman spectroscopy. The PL intensity of PS and PS/Fe increases at low temperature, the evolution of integrated PL intensity follows the modified Arrhenius model. The incorporation of iron in PS matrix reduces the activation energy traducing the existence of shallow levels related to iron atoms. Also, the temperature dependence of the porous silicon PL peak position follows a linear evolution at high temperature and a quadratic one at low temperature. Such evolution is due to the thermal carriers' redistribution and an energy transfer. Similarly, we have compared the laser power dependence of the PL in PS and PS/Fe layers. The results prove that the recombination process in PS is realised through the lower energy traps localised in the electronic gap. However, the observed emission in PS/Fe is essentially due to direct transitions. So, we can conclude that the presence of iron in PS matrix induces a strong modification of the PL mechanisms.

Material for electrodes of low temperature plasma generators

DOEpatents

Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich

2008-12-09

Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron: 3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, and municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

Material for electrodes of low temperature plasma generators

DOEpatents

Caplan, Malcolm; Vinogradov, Sergel Evge'evich; Ribin, Valeri Vasil'evich; Shekalov, Valentin Ivanovich; Rutberg, Philip Grigor'evich; Safronov, Alexi Anatol'evich; Shiryaev, Vasili Nikolaevich

2010-03-02

Material for electrodes of low temperature plasma generators. The material contains a porous metal matrix impregnated with a material emitting electrons. The material uses a mixture of copper and iron powders as a porous metal matrix and a Group IIIB metal component such as Y.sub.2O.sub.3 is used as a material emitting electrons at, for example, the proportion of the components, mass %: iron:3-30; Y.sub.2O.sub.3:0.05-1; copper: the remainder. Copper provides a high level of heat conduction and electric conductance, iron decreases intensity of copper evaporation in the process of plasma creation providing increased strength and lifetime, Y.sub.2O.sub.3 provides decreasing of electronic work function and stability of arc burning. The material can be used for producing the electrodes of low temperature AC plasma generators used for destruction of liquid organic wastes, medical wastes, municipal wastes as well as for decontamination of low level radioactive waste, the destruction of chemical weapons, warfare toxic agents, etc.

Characterizing cosmochemical materials with genetic affinities to the Earth: Genetic and chronological diversity within the IAB iron meteorite complex

NASA Astrophysics Data System (ADS)

Worsham, Emily A.; Bermingham, Katherine R.; Walker, Richard J.

2017-06-01

The IAB iron meteorite complex consists of a main group (MG) and five chemical subgroups (sLL, sLM, sLH, sHL, and sHH). Here, mass-independent Mo and radiogenic 182W isotope compositions are reported for IAB complex meteorites to evaluate the genetics and chronology, respectively, of the MG and subgroups. Osmium isotopes are used to correct for cosmic ray exposure effects on isotopes of Mo and W. The MG and three subgroups (i.e., sLL, sLM, and sLH), characterized by low Au abundances, have the same Mo isotopic compositions within analytical uncertainty, consistent with a common genetic origin. These meteorites, together with winonaites, are the only cosmochemical materials yet identified with Mo isotopic compositions that are identical to Earth. The Mo isotopic compositions of two subgroups characterized by higher Au abundances (sHL and sHH) are identical to one another within uncertainty, but differ from the low Au subgroups, indicating derivation from genetically distinct materials. The MG has a 182W, post calcium-aluminum inclusion (CAI) formation model age of 3.4 ± 0.7 Ma. One of the low Au subgroups (sLM) is ∼1.7 Ma younger, whereas the high Au subgroups are ∼1.5-3 Ma older. The new Mo-W data, coupled with chemical data, indicate that the MG and the low Au subgroups formed in different impact-generated melts, some of which evidently formed on a chemically disparate, but genetically identical parent body. The high Au subgroups likely formed via core-formation processes on separate, internally-heated parent bodies from other IAB subgroups. The IAB complex meteorites fall on a linear trend defined by 94Mo/96Mo vs. 95Mo/96Mo, along with most other iron meteorite groups. Variation along this line was caused by mixing between at least two nebular components. One component was likely a pure s-process enriched nucleosynthetic carrier, and the other a homogenized nebular component. Sombrerete, currently classified as an sHL iron, has a Mo isotopic composition that is distinct from all IAB complex meteorites analyzed here. Along with group IVB iron meteorites and some ungrouped iron meteorites, it falls on a separate line from other meteorites which may reflect addition of an r-process-enriched component, and it should no longer be classified as a IAB iron.

Extraction of titanium from low-iron nitrided Malaysian ilmenite by chlorination

NASA Astrophysics Data System (ADS)

Ibrahim, Najwa; Ahmadi, Eltefat; Rahman, Shaik Abdul; Fauzi, M. N. Ahmad; Rezan, Sheikh Abdul

2017-01-01

In this paper, production of TiCl4 from low-iron nitrided ilmenite samples at relatively low temperature using chlorine gas generated from the reaction between KMnO4 and HCl has been investigated. The effects of chlorination soaking time, potassium permanganate (KMnO4) to hydrochloric acid (HCl) molar ratio and aluminium powder catalyst in chlorine gas generation on titanium extraction from nitrided Malaysian ilmenite were examined. The low-iron nitrided Malaysian ilmenite contained titanium oxycarbonitride (TiOxCyNz) after carbothermal reduction and nitridation with subsequent leaching. Chlorination process was performed at 500°C for 30 - 60 minutes. Statistical analysis of the data was done by Design of Experiment (DOE) to identify the significant variables and their interactions. The results achieved in this study showed that the highest extent of chlorination was about 98.34% at 500°C for 60 minutes. The lowest extent of chlorination was about 68.51% obtained in KMnO4 to HCl molar ratio of 2.0 and 0.35 g of aluminium powder. The chlorinated titanium oxycarbonitride powders and TiCl4 solutions were analyzed by X-ray diffraction (XRD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The purpose of this study was to explore the relationship between the processing parameters on extracting titanium via pyrometallurgical technique.

Organically modified low-grade kaolin as a secondary containment material for underground storage tanks.

PubMed

Moon, Chul-Hwan; Lee, Jai-Young; Oh, Byung-Taek; Choi, Sang-Il

2007-08-01

Batch scale reactions were conducted to evaluate the efficacy of modified low-grade kaolin for the treatment of petroleum contaminants. Low-grade kaolin, which has been unvalued as material in the mining process because of its low quality for commercial products, was modified with HDTMA (hexadecyl-trimethylammonium), and its efficiency was compared with that of HDTMA-modified bentonite, which is used as a secondary containment barrier for underground storage tanks. The sorption capacity and hydraulic conductivity of both the HDTMA-modified bentonite and low-grade kaolin were investigated and showed distribution coefficients in the sorption of benzene, toluene, ethylbenzene and xylene ranging between 45.7 and 583.7 and 57.0 and 525.1, respectively. The hydraulic conductivities were 2.53 x 10(-8) and 5.62 x 10(-8) cm/s for the HDTMA-modified bentonite and low-grade kaolin, respectively. These results suggest that HDTMA-modified low-grade kaolin could be used as a hydraulic barrier against advection migration of petroleum contaminants. Simulation of the one-dimensional transport of benzene through a liner made of either one of the compounds was also performed. These results also showed that HDTMA-modified kaolin more effectively retards the transport of benzene.

Ligand-controlled Fe mobilization catalyzed by adsorbed Fe(II) on Fe(hydr)oxides

NASA Astrophysics Data System (ADS)

Kang, Kyounglim; Biswakarma, Jagannath; Borowski, Susan C.; Hug, Stephan J.; Hering, Janet G.; Schenkeveld, Walter D. C.; Kraemer, Stephan M.

2017-04-01

Dissolution of Fe(hydr)oxides is a key process in biological iron acquisition. Due to the low solubility of iron oxides in environments with a circumneutral pH, organisms may exude organic compounds catalyzing iron mobilization by reductive and ligand controlled dissolution mechanisms. Recently, we have shown synergistic effects between reductive dissolution and ligand-controlled dissolution that may operate in biological iron acquisition. The synergistic effects were observed in Fe mobilization from single goethite suspensions as well as in suspensions containing calcareous soil[1],[2]. However, how the redox reaction accelerates Fe(hydr)oxide dissolution by ligands is not studied intensively. In our study, we hypothesized that electron transfer to structural Fe(III) labilizes the Fe(hydr)oxide structure, and that this can accelerate ligand controlled dissolution. Systematical batch dissolution experiments were carried out under anoxic conditions at environmentally relevant pH values in which various Fe(hydr)oxides (goethite, hematite, lepidocrocite) interacted with two different types of ligand (desferrioxamine B (DFOB) and N,N'-Di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride (HBED)). Electron transfer to the structure was induced by adsorbing Fe(II) to the mineral surface at various Fe(II) concentrations. Our results show a distinct catalytic effect of adsorbed Fe(II) on ligand controlled dissolution, even at submicromolar Fe(II) concentrations. We observed the effect for a range of iron oxides, but it was strongest in lepidocrocite, most likely due to anisotropy in conductivity leading to higher near-surface concentration of reduced iron. Our results demonstrate that the catalytic effect of reductive processes on ligand controlled dissolution require a very low degree of reduction making this an efficient process for biological iron acquisition and a potentially important effect in natural iron cycling. References 1. Wang, Z. M.; Schenkeveld, W. D. C.; Kraemer, S. M.; Giammar, D. E. Environ. Sci. Technol. 2015, 49, (12), 7236-7244. 2. Schenkeveld, W. D. C.; Wang, Z. M.; Giammar, D. E.; Kraemer, S. M. Environ. Sci. Technol. 2016, 50, (12), 6381-6388.

Hydrogen peroxide-enhanced iron-mediated aeration for the treatment of mature landfill leachate.

PubMed

Deng, Yang; Englehardt, James D

2008-05-01

Municipal landfill leachate is being disallowed for biological treatment by some sewer authorities due to its recalcitrance and corrosiveness, and therefore physicochemical treatment may be needed. In this paper, hydrogen peroxide-enhanced iron (Fe(0))-mediated aeration (IMA) was studied as an alternative for the treatment of mature landfill leachate. Bench-scale Taguchi array screening tests and full factorial tests were conducted. Iron grade, initial pH, H(2)O(2) addition rate, and aeration rate significantly influenced both overall chemical oxygen demand (COD) removal and iron consumption. In the enhanced IMA-treated leachate at an initial pH of 8.2, COD was reduced by 50% due to oxidation and coagulation, a level almost equivalent to those obtained by Fenton treatment. Meanwhile, the 5-day biochemical oxygen demand (BOD(5))/COD ratio was increased from 0.02 to 0.17. In particular, the effect of initial pH became minor at H(2)O(2) addition rate greater than the theoretical demand for complete oxidation of organics by H(2)O(2). In addition, 83% of 300 mg/L ammonia nitrogen and 38% of 8.30 mS/cm electrical conductivity were removed when the initial pH was not adjusted. Based on these results, the process appears suitable for treatment of mature leachate.

Anaemia control: lessons from the flour fortification programme.

PubMed

Sadighi, J; Mohammad, K; Sheikholeslam, R; Amirkhani, M A; Torabi, P; Salehi, F; Abdolahi, Z

2009-12-01

Anaemia is an important public health problem in Iran; therefore, a programme of flour fortification with iron was launched in two pilot provinces. The present study was conducted in January 2009 to evaluate the effectiveness and process of this programme. A 'before-and-after study' was conducted to evaluate the effectiveness of the flour fortification programme, and the process of the programme was evaluated using a cross-sectional study. To evaluate the effectiveness of the programme, blood haemoglobin and ferritin levels were measured in sample populations from Bushehr and Golestan provinces. The target population was women aged 15-49 years. Iron content was measured in samples of flour and bread to evaluate the flour fortification process in these two national pilot provinces. The total study population was 600 women from Bushehr province and 652 women from Golestan province. Similar trends were found in the indicators of anaemia/iron deficiency among the women studied in both provinces. The flour fortification programme only appears to have had a beneficial effect on ferritin levels (iron deficiency) in the two provinces. The prevalence of iron-deficiency anaemia before and after the intervention did not differ significantly in either province. Interestingly, the prevalence of anaemia (low haemoglobin) was significantly higher after the intervention in women from both provinces. The coverage of fortified flour and bread was 90% and 98.7% in Bushehr province, and 94.1% and 95% in Golestan province, respectively. In areas where anaemia is not mainly due to iron deficiency, an iron fortification programme might decrease the prevalence of iron deficiency without affecting the prevalence of anaemia.

Haemoglobin variants, iron status and anaemia in Sri Lankan adolescents with low red cell indices: A cross sectional survey.

PubMed

Rodrigo, Rexan; Allen, Angela; Manampreri, Aresha; Perera, Luxman; Fisher, Christopher A; Allen, Stephen; Weatherall, David J; Premawardhena, Anuja

2018-07-01

Iron deficiency complicates the use of red cell indices to screen for carriers of haemoglobin variants in many populations. In a cross sectional survey of 7526 secondary school students from 25 districts of Sri Lanka, 1963 (26.0%) students had low red cell indices. Iron deficiency, identified by low serum ferritin, was the major identifiable cause occurring in 550/1806 (30.5%) students. Low red cell indices occurred in iron-replete students with alpha-thalassaemia including those with single alpha-globin gene deletions. Anaemia and low red cell indices were also common in beta-thalassaemia trait. An unexpected finding was that low red cell indices occurred in 713 iron-replete students with a normal haemoglobin genotype. It is common practice to prescribe iron supplements to individuals with low red cell indices. Since low red cell indices were a feature of all forms of α thalassaemia and also of iron deficiency, in areas where both conditions are common, such as Sri Lanka, it is imperative to differentiate between the two, to allow targeted administration of iron supplements and avoid the possible deleterious effects of increased iron availability in iron replete individuals with low red cell indices due to other causes such as α thalassaemia. Copyright © 2018 Elsevier Inc. All rights reserved.

Recovery of ferrous and nonferrous metal from ASR by physical separation

NASA Astrophysics Data System (ADS)

Kim, Min-gyu; Han, Oh-hyung; Park, Chul-hyun

2017-04-01

A recycle ratio of waste automobiles in Korea is low, compared to that of the advanced countries. Especially in its recycle, separation of automotive shredder residue (ASR), the residual fraction of approximate 25% obtained after dismantling and shredding from waste car, is needed. However ASR is cannot be effectively separated due to its heterogeneous materials and coated or laminated complexes and then is largely deposited in land-fill sites as waste. In this study ASR was separated by a series of physical processing operations such as comminution, air classification and magnetic separation and electrostatic separations. In particular it focuses on estimating the optimal conditions of magnetic and electrostatic separations for improving the separation efficiency of valuable ferrous and non-ferrous metals such as iron (Fe), aluminum, copper and etc. In magnetic separation, 91.5% Fe grade and 91% recovery could be obtained at conditions of particle size under 10mm and magnetic intensity of 400 gauss. In corona electrostatic separation for recovering nonferrous metals, a grade of 79.2% and recovery of 90.7% could be successfully achieved under conditions of -6mm particle size, 50kV electrode potential, 35rpm drum speed and 20 degree splitter position, respectively. Acknowledgments This study was supported by the R&D Center for Valuable Recycling (Global-Top R&BD Program) of the Ministry of Environment. (Project No. 2016002250001)

The essential role of coumarin secretion for Fe acquisition from alkaline soil

PubMed Central

Clemens, Stephan; Weber, Michael

2016-01-01

ABSTRACT Plant productivity is limited by the scarcity of the essential micronutrient iron particularly in alkaline soils. The root secretion of phenolics has long been recognized as a component of the acidification-reduction strategy to acquire iron (strategy I). However, very little molecular insight into this process was available until recently several research groups independently discovered the important role of coumarins for the growth of Arabidopsis thaliana under Fe-limited conditions. Genome-wide analyses of iron deficiency responses, mutant screening and metabolomics experiments all converged on the finding that the synthesis and root exudation of scopoletin, esculetin and other coumarins is essential for iron uptake from substrates with low iron availability. Here we describe the evidence supporting this conclusion and discuss important questions that now have to be addressed in order to better understand the mechanistic basis of coumarin-dependent iron uptake and its significance within the plant kingdom. PMID:26618918

Mineralogy and crystal chemistry of iron in the Timan bauxite and products of their technological processing

NASA Astrophysics Data System (ADS)

Kotova, O.; Silaev, V.; Lutoev, V.; Vakhrushev, A.

2016-04-01

Mineralogical and geochemical features of two series of samples of typical bauxites from two deposits of Middle Timan mining area (Vezhayu-Vorykva and Svetlinskoe) were studied. The phase composition of ferrous bauxites generally is boehmite, hematite, ultradisperse low-ordered goethite and berthierine. In a boehmite and kaolinite structural impurity of iron to 10%, and in the iron oxidehydroxides aluminum impurity is revealed. On iron content bauxites are subdivided into three mineral types for which quantitative data on valence states of ions of iron and proportions of their distribution last on nonequivalent structural positions in hematite, goethite and berthierine are obtained. Noble metals (Ag, Au, Ir, Rh, Pd) concentrating in bauxites are revealed for the first time. Obtained data can lead to decrease of power consumption during aluminum production and high quality ceramics, to provide production of valuable iron oxide, and also to minimize the ecological harm from accumulation of bauxite wastes.

Iron solubility related to particle sulfur content in source emission and ambient fine particles.

PubMed

Oakes, M; Ingall, E D; Lai, B; Shafer, M M; Hays, M D; Liu, Z G; Russell, A G; Weber, R J

2012-06-19

The chemical factors influencing iron solubility (soluble iron/total iron) were investigated in source emission (e.g., biomass burning, coal fly ash, mineral dust, and mobile exhaust) and ambient (Atlanta, GA) fine particles (PM2.5). Chemical properties (speciation and mixing state) of iron-containing particles were characterized using X-ray absorption near edge structure (XANES) spectroscopy and micro-X-ray fluorescence measurements. Bulk iron solubility (soluble iron/total iron) of the samples was quantified by leaching experiments. Major differences were observed in iron solubility in source emission samples, ranging from low solubility (<1%, mineral dust and coal fly ash) up to 75% (mobile exhaust and biomass burning emissions). Differences in iron solubility did not correspond to silicon content or Fe(II) content. However, source emission and ambient samples with high iron solubility corresponded to the sulfur content observed in single particles. A similar correspondence between bulk iron solubility and bulk sulfate content in a series of Atlanta PM2.5 fine particle samples (N = 358) further supported this trend. In addition, results of linear combination fitting experiments show the presence of iron sulfates in several high iron solubility source emission and ambient PM2.5 samples. These results suggest that the sulfate content (related to the presence of iron sulfates and/or acid-processing mechanisms by H(2)SO(4)) of iron-containing particles is an important proxy for iron solubility.

Iron Overload and Chelation Therapy in Non-Transfusion Dependent Thalassemia

PubMed Central

Bou-Fakhredin, Rayan; Bazarbachi, Abdul-Hamid; Chaya, Bachar; Sleiman, Joseph; Cappellini, Maria Domenica; Taher, Ali T.

2017-01-01

Iron overload (IOL) due to increased intestinal iron absorption constitutes a major clinical problem in patients with non-transfusion-dependent thalassemia (NTDT), which is a cumulative process with advancing age. Current models for iron metabolism in patients with NTDT suggest that suppression of serum hepcidin leads to an increase in iron absorption and subsequent release of iron from the reticuloendothelial system, leading to depletion of macrophage iron, relatively low levels of serum ferritin, and liver iron loading. The consequences of IOL in patients with NTDT are multiple and multifactorial. Accurate and reliable methods of diagnosis and monitoring of body iron levels are essential, and the method of choice for measuring iron accumulation will depend on the patient’s needs and on the available facilities. Iron chelation therapy (ICT) remains the backbone of NTDT management and is one of the most effective and practical ways of decreasing morbidity and mortality. The aim of this review is to describe the mechanism of IOL in NTDT, and the clinical complications that can develop as a result, in addition to the current and future therapeutic options available for the management of IOL in NTDT. PMID:29261151

Excitation and charge transfer in low-energy hydrogen atom collisions with neutral iron

NASA Astrophysics Data System (ADS)

Barklem, P. S.

2018-05-01

Data for inelastic processes due to hydrogen atom collisions with iron are needed for accurate modelling of the iron spectrum in late-type stars. Excitation and charge transfer in low-energy Fe+H collisions is studied theoretically using a previously presented method based on an asymptotic two-electron linear combination of atomic orbitals model of ionic-covalent interactions in the neutral atom-hydrogen-atom system, together with the multi-channel Landau-Zener model. An extensive calculation including 166 covalent states and 25 ionic states is presented and rate coefficients are calculated for temperatures in the range 1000-20 000 K. The largest rates are found for charge transfer processes to and from two clusters of states around 6.3 and 6.6 eV excitation, corresponding in both cases to active 4d and 5p electrons undergoing transfer. Excitation and de-excitation processes among these two sets of states are also significant. Full Tables and rate coefficient data are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/612/A90

Tribological characteristics of gold films deposited on metals by ion plating and vapor deposition

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Spalvins, T.; Buckley, D. H.

1984-01-01

The graded interface between an ion-plated film and a substrate is discussed as well as the friction and wear properties of ion-plated gold. X-ray photoelectron spectroscopy (XPS) depth profiling and microhardness depth profiling were used to investigate the interface. The friction and wear properties of ion-plated and vapor-deposited gold films were studied both in an ultra high vacuum system to maximize adhesion and in oil to minimize adhesion. The results indicate that the solubility of gold on the substrate material controls the depth of the graded interface. Thermal diffusion and chemical diffusion mechanisms are thought to be involved in the formation of the gold-nickel interface. In iron-gold graded interfaces the gold was primarily dispersed in the iron and thus formed a physically bonded interface. The hardness of the gold film was influenced by its depth and was also related to the composition gradient between the gold and the substrate. The graded nickel-gold interface exhibited the highest hardness because of an alloy hardening effect. The effects of film thickness on adhesion and friction were established.

Tribological characteristics of gold films deposited on metals by ion plating and vapor deposition

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Spalvins, T.; Buckley, D. H.

1986-01-01

The graded interface between an ion-plated film and a substrate is discussed as well as the friction and wear properties of ion-plated gold. X-ray photoelectron spectroscopy (XPS) depth profiling and microhardness depth profiling were used to investigate the interface. The friction and wear properties of ion-plated and vapor-deposited gold films were studied both in an ultra high vacuum system to maximize adhesion and in oil to minimize adhesion. The results indicate that the solubility of gold on the substrate material controls the depth of the graded interface. Thermal diffusion and chemical diffusion mechanisms are thought to be involved in the formation of the gold-nickel interface. In iron-gold graded interfaces the gold was primarily dispersed in the iron and thus formed a physically bonded interface. The hardness of the gold film was influenced by its depth and was also related to the composition gradient between the gold and the substrate. The graded nickel-gold interface exhibited the highest hardness because of an alloy hardening effect. The effects of film thickness on adhesion and friction were established.

Comparison of Different Post-Processing Algorithms for Dynamic Susceptibility Contrast Perfusion Imaging of Cerebral Gliomas.

PubMed

Kudo, Kohsuke; Uwano, Ikuko; Hirai, Toshinori; Murakami, Ryuji; Nakamura, Hideo; Fujima, Noriyuki; Yamashita, Fumio; Goodwin, Jonathan; Higuchi, Satomi; Sasaki, Makoto

2017-04-10

The purpose of the present study was to compare different software algorithms for processing DSC perfusion images of cerebral tumors with respect to i) the relative CBV (rCBV) calculated, ii) the cutoff value for discriminating low- and high-grade gliomas, and iii) the diagnostic performance for differentiating these tumors. Following approval of institutional review board, informed consent was obtained from all patients. Thirty-five patients with primary glioma (grade II, 9; grade III, 8; and grade IV, 18 patients) were included. DSC perfusion imaging was performed with 3-Tesla MRI scanner. CBV maps were generated by using 11 different algorithms of four commercially available software and one academic program. rCBV of each tumor compared to normal white matter was calculated by ROI measurements. Differences in rCBV value were compared between algorithms for each tumor grade. Receiver operator characteristics analysis was conducted for the evaluation of diagnostic performance of different algorithms for differentiating between different grades. Several algorithms showed significant differences in rCBV, especially for grade IV tumors. When differentiating between low- (II) and high-grade (III/IV) tumors, the area under the ROC curve (Az) was similar (range 0.85-0.87), and there were no significant differences in Az between any pair of algorithms. In contrast, the optimal cutoff values varied between algorithms (range 4.18-6.53). rCBV values of tumor and cutoff values for discriminating low- and high-grade gliomas differed between software packages, suggesting that optimal software-specific cutoff values should be used for diagnosis of high-grade gliomas.

Iron-Coupled Anaerobic Oxidation of Methane Performed by a Mixed Bacterial-Archaeal Community Based on Poorly Reactive Minerals.

PubMed

Bar-Or, Itay; Elvert, Marcus; Eckert, Werner; Kushmaro, Ariel; Vigderovich, Hanni; Zhu, Qingzeng; Ben-Dov, Eitan; Sivan, Orit

2017-11-07

Anaerobic oxidation of methane (AOM) was shown to reduce methane emissions by over 50% in freshwater systems, its main natural contributor to the atmosphere. In these environments iron oxides can become main agents for AOM, but the underlying mechanism for this process has remained enigmatic. By conducting anoxic slurry incubations with lake sediments amended with 13 C-labeled methane and naturally abundant iron oxides the process was evidenced by significant 13 C-enrichment of the dissolved inorganic carbon pool and most pronounced when poorly reactive iron minerals such as magnetite and hematite were applied. Methane incorporation into biomass was apparent by strong uptake of 13 C into fatty acids indicative of methanotrophic bacteria, associated with increasing copy numbers of the functional methane monooxygenase pmoA gene. Archaea were not directly involved in full methane oxidation, but their crucial participation, likely being mediators in electron transfer, was indicated by specific inhibition of their activity that fully stopped iron-coupled AOM. By contrast, inhibition of sulfur cycling increased 13 C-methane turnover, pointing to sulfur species involvement in a competing process. Our findings suggest that the mechanism of iron-coupled AOM is accomplished by a complex microbe-mineral reaction network, being likely representative of many similar but hidden interactions sustaining life under highly reducing low energy conditions.

Effect of biopolymer on the dewatering characteristics of autothermal thermophilic aerobic digestion of sludges.

PubMed

Agarwal, S; Abu-Orf, M M; Novak, J T

2006-03-01

Autothermal thermophilic aerobic digestion of sludge is known to produce poorly dewatering sludges. Laboratory studies were conducted to investigate the reasons for the poor dewatering. It was found that, during digestion, proteins and polysaccharides were released into solution, and that these could be linked to the deterioration in dewatering. The biopolymer release was accompanied by an increase in the monovalent-to-divalent (M/D) cation ratio. The degree to which the M/D caused deterioration of the sludges depended on the presence of iron in sludge. When the iron content was high, the release of protein and polysaccharides was low. When iron was low, the release of protein and polysaccharides increased linearly with the M/D ratio. The dose of conditioning chemicals, cationic polymer or ferric chloride, was related to the amount of colloidal biopolymer present in solution. The findings suggest that the addition of iron during the digestion process has the potential to produce better dewatering sludges.

Effects of iron on arsenic speciation and redox chemistry in acid mine water

USGS Publications Warehouse

Bednar, A.J.; Garbarino, J.R.; Ranville, J.F.; Wildeman, T.R.

2005-01-01

Concern about arsenic is increasing throughout the world, including areas of the United States. Elevated levels of arsenic above current drinking-water regulations in ground and surface water can be the result of purely natural phenomena, but often are due to anthropogenic activities, such as mining and agriculture. The current study correlates arsenic speciation in acid mine drainage and mining-influenced water with the important water-chemistry properties Eh, pH, and iron(III) concentration. The results show that arsenic speciation is generally in equilibrium with iron chemistry in low pH AMD, which is often not the case in other natural-water matrices. High pH mine waters and groundwater do not always hold to the redox predictions as well as low pH AMD samples. The oxidation and precipitation of oxyhydroxides deplete iron from some systems, and also affect arsenite and arsenate concentrations through sorption processes. ?? 2004 Elsevier B.V. All rights reserved.

Effect of tea on iron absorption from the typical Tunisian meal 'couscous' fed to healthy rats.

PubMed

Hamdaoui, M; Hedhili, A; Doghri, T; Tritar, B

1994-01-01

Black and green tea decoctions are popular beverages in Tunisia, especially after eating. Our study was performed to examine the effect of graded amounts of black and green tea decoction prepared under realistic Tunisian conditions on nonheme iron absorption from a typical Tunisian meal, 'couscous', by extrinsic radioiron labeling in rats. Concentrations of 300, 200 and 100 micrograms/ml of black tea decreased dramatically nonheme iron bioavailability from couscous, but 50 micrograms/ml did not influence iron absorption. The inhibition of nonheme iron from couscous varied from 36 to 61% with black tea and 30.5% with green tea. Taken together, our findings show that the tea decoction in Tunisia has a great inhibitory power and may constitute an important factor for the development of iron deficiency anemia throughout Tunisia.

Hematite-coated microfossils: primary ecological fingerprint or taphonomic oddity of the Paleoproterozoic?

PubMed

Shapiro, R S; Konhauser, K O

2015-05-01

Microfossils belonging to the 1.88-billion-year-old 'Gunflint-biota' are preserved as carbonaceous and hematitic filaments and spheres that are believed to represent ancient chemolithoautotrophic Fe(II) oxidizing bacteria that grew above a chemocline where ferruginous seawater upwelled into shallow, oxygenated waters. This 'biological' model posits that hematite formed during burial from dewatering of the precursor ferric oxyhydroxides that encrusted Fe(II)-oxidizing bacteria. Here, we present an alternate 'taphonomic' model in which iron-rich groundwaters discharged into buried stromatolites; thus, the mineralization reactions are more informative of diagenetic processes than they are for primary marine conditions. We sampled centimeter-scale columnar stromatolites from both the lower and upper stromatolite horizons of the Biwabik and Gunflint formations, across a range of metamorphic gradients including unaltered to prehnite-pumpellyite taconite, supergene altered ore, and amphibolite-pyroxene grade contact-metamorphic zones. Fossils are rare to very rare and comprise curved filaments that exist in clusters with similar orientations. The filaments from throughout the Biwabik are similar to well-preserved carbonaceous Gunflintia from Ontario. Spheres of Huroniospora are also found in both formations. Microfossils from the least altered sections are preserved as carbon. Prehnite-pumpellyite samples are composed of either carbon or hematite (Fe2 O3 ). Within the contact aureole, filaments are densely coated by magnetite (Fe3 O4 ); the highest grade samples are secondarily oxidized to martite. The consistency in stromatolite microstructure and lithofacies throughout the metamorphic grades suggests they formed under similar environmental conditions. Post-depositional alteration led to replacement of the carbon by iron oxide. The facies association, filament distribution, and lack of branching and attached spherical cells argue against Gunflintia being a direct analogue to common marine, chemolithoautotrophic Fe(II)-oxidizing bacteria. Instead, we propose that the presence of hematite-coated microfossils is a reflection of taphonomic processes and does not necessarily reflect the byproduct of an original microbial ecosystem. © 2015 John Wiley & Sons Ltd.

Magnetic iron oxides in the cementation technology of the boron-containing radioactive waste

NASA Astrophysics Data System (ADS)

Fedotov, M. A.; Gorbunova, O. A.; Fedorova, O. V.; Folmanis, G. E.; Kovalenko, L. V.

2015-04-01

Two ways of synthesis of non-detachable dispersed particles of magnetic materials useful for the boron-containing waste cementation process regulation were developed. Powder XRD showed that the method of carbothermic recovery of nanoscale iron hydroxide allows obtaining a mixture of iron oxides with content of the magnetic phase up to 70%. Method of low-temperature hydrogen reduction of the raw materials allows obtaining various compositions of a-iron and iron oxides with the possibility to change the size of the final particles in a wide range. The possibility of using composites of magnetic iron oxides and metal oxide compositions instead of ferromagnetic rods with VEP of boron-containing liquid radioactive waste in the fluidized field was studied. It was shown that the use of fine and nano particles of the iron oxides in the pre-treatment of the boron-containing LRW increases the strength of the final compounds and accelerates the cement setting compounds from 13 to 5-9 days.

Oxidation-reduction processes in ground water at Naval Weapons Industrial Reserve Plant, Dallas, Texas

USGS Publications Warehouse

Jones, S.A.; Braun, Christopher L.; Lee, Roger W.

2003-01-01

Concentrations of trichloroethene in ground water at the Naval Weapons Industrial Reserve Plant in Dallas, Texas, indicate three source areas of chlorinated solvents?building 1, building 6, and an off-site source west of the facility. The presence of daughter products of reductive dechlorination of trichloroethene, which were not used at the facility, south and southwest of the source areas are evidence that reductive dechlorination is occurring. In places south of the source areas, dissolved oxygen concentrations indicated that reduction of oxygen could be the dominant process, particularly south of building 6; but elevated dissolved oxygen concentrations south of building 6 might be caused by a leaking water or sewer pipe. The nitrite data indicate that denitrification is occurring in places; however, dissolved hydrogen concentrations indicate that iron reduction is the dominant process south of building 6. The distributions of ferrous iron indicate that iron reduction is occurring in places south-southwest of buildings 6 and 1; dissolved hydrogen concentrations generally support the interpretation that iron reduction is the dominant process in those places. The generally low concentrations of sulfide indicate that sulfate reduction is not a key process in most sampled areas, an interpretation that is supported by dissolved hydrogen concentrations. Ferrous iron and dissolved hydrogen concentrations indicate that ferric iron reduction is the primary oxidation-reduction process. Application of mean first-order decay rates in iron-reducing conditions for trichloroethene, dichloroethene, and vinyl chloride yielded half-lives for those solvents of 231, 347, and 2.67 days, respectively. Decay rates, and thus half-lives, at the facility are expected to be similar to those computed. A weighted scoring method to indicate sites where reductive dechlorination might be likely to occur indicated strong evidence for anaerobic biodegradation of chlorinated solvents at six sites. In general, scores were highest for samples collected on the northeast side of the facility.

Micronuclei as biomarkers for evaluating the risk of malignant transformation in the uterine cervix.

PubMed

Aires, G M A; Meireles, J R C; Oliveira, P C; Oliveira, J L; Araújo, E L; Pires, B C; Cruz, E S A; Jesus, N F; Pereira, C A B; Cerqueira, E M M

2011-01-01

We evaluated micronucleus and apoptosis occurrence among women with normal smears and women with different kinds of cervical abnormalities, i.e., inflammatory processes and low- and high-grade squamous intraepithelial lesions (N = 12, N = 10 and N = 27, respectively). The sample included 59 women who were seen at a public medical service for cervical cancer prevention in Feira de Santana, Bahia, Brazil. The diagnosis was established by means of cytological, colposcopic, and histopathological examination. Cytogenetic analysis was performed on 2000 cells from each woman and included assessment of micronuclei and nuclear degenerative abnormalities indicative of apoptosis (karyorrhexis, pyknosis and condensed chromatin). Micronucleus frequency was significantly higher in the women with high-grade squamous intraepithelial lesions than in the women without cervical abnormalities or inflammatory processes (P< 0.001) or in the women with low-grade squamous intraepithelial lesions (P < 0.005). The frequency of apoptosis was similar in women without cervical abnormalities and women showing high-grade squamous intraepithelial lesions (P > 0.50), and significantly lower in women without cervical abnormalities and in women showing high-grade squamous intraepithelial lesions than in women showing inflammatory processes or low-grade squamous intraepithelial lesions (P < 0.0001). These results indicate that, in addition to Papanicolaou cervical cytological analysis, it would be useful to use micronucleus analysis to screen women who are at risk of developing cervical cancer. The assessment of nuclear degenerative abnormalities indicative of apoptosis increased the sensitivity of this test.

Flavor characteristics of seven grades of black tea produced in Turkey.

PubMed

Alasalvar, Cesarettin; Topal, Bahar; Serpen, Arda; Bahar, Banu; Pelvan, Ebru; Gökmen, Vural

2012-06-27

Seven grades of black tea [high-quality black tea (grades 1-3) and low-quality black tea (grades 4-7)], processed by ÇAYKUR Tea Processing Plant (Rize, Turkey), were compared for their differences in descriptive sensory analysis (DSA), aroma-active compounds (volatile compounds), and taste-active compounds (sugar, organic acid, and free amino acid compositions). Ten flavor attributes such as 'after taste', 'astringency', 'bitter', 'caramel-like', 'floral/sweet', 'green/grassy', 'hay-like', 'malty', 'roasty', and 'seaweed' were identified. Intensities for a number of flavor attributes ('after taste', 'caramel-like', 'malty', and 'seaweed') were not significantly different (p > 0.05) among seven grades of black tea. A total of 57 compounds in seven grades of black tea (14 aldehydes, eight alcohols, eight ketones, two esters, four aromatic hydrocarbons, five aliphatic hydrocarbons, nine terpenes, two pyrazines, one furan, two acids, and two miscellaneous compounds) were tentatively identified. Of these, aldeyhdes comprised more than 50% to the total volatile compounds identified. In general, high-grade quality tea had more volatiles than low-grade quality tea. With respect to taste-active compounds, five sugars, six organic acids, and 18 free amino acids were positively identified in seven grades of black tea, of which fructose, tannic acid, and theanine predominated, respectively. Some variations (p < 0.05), albeit to different extents, were observed among volatile compounds, sugars, organic acids, and free amino acids in seven grades of black tea. The present study suggests that a certain flavor attributes correlate well with taste- and aroma-active compounds. High- and low-quality black teas should not be distinguished solely on the basis of their DSA and taste- and aroma-active compounds. The combination of taste-active compounds together with aroma-active compounds renders combination effects that provide the characteristic flavor of each grade of black tea.

Effects of acidic recharge on groundwater at the St. Kevin Gulch site, Leadville, Colorado

USGS Publications Warehouse

Paschke, S.S.; Harrison, W.J.; Walton-Day, K.

2001-01-01

The acid rock drainage-affected stream of St. Kevin Gulch recharges the Quaternary sand and gravel aquifer of Tennessee Park, near Leadville, Colorado, lowering pH and contributing iron, cadmium, copper, zinc and sulphate to the ground-water system. Dissolved metal mobility is controlled by the seasonal spring runoff as well as oxidation/reduction (redox) reactions in the aquifer. Oxidizing conditions occur in the unconfined portions of the aquifer whilst sulphate-reducing conditions are found down gradient where semi-confined groundwater flow occurs beneath a natural wetland. Iron-reducing conditions occur in the transition from unconfined to semi-confined groundwater flow. Dissolved iron concentrations are low to not detectable in the alluvial fan recharge zone and increase in a down gradient direction. The effects of low-pH, metal-rich recharge are pronounced during low-flow in the fall when there is a defined area of low pH groundwater with elevated concentrations of dissolved zinc, cadmium, copper and sulphate adjacent to St. Kevin Gulch. Dissolved metal and sulphate concentrations in the recharge zone are diluted during spring runoff, although the maximum concentrations of dissolved zinc, cadmium, copper and sulphate occur at selected down gradient locations during high flow. Dissolved zinc, cadmium and copper concentrations are low to not detectable, whereas dissolved iron concentrations are greatest, in groundwater samples from the sulphate-reducing zone. Attenuation of zinc, cadmium and copper beneath the wetland suggests sulphide mineral precipitation is occurring in the semi-confined aquifer, in agreement with previous site investigations and saturation index calculations. Adsorption of dissolved zinc, cadmium and copper onto iron hydroxides is a minor attenuation process due to the low pH of the groundwater system.

Iron speciation of airborne subway particles by the combined use of energy dispersive electron probe X-ray microanalysis and Raman microspectrometry.

PubMed

Eom, Hyo-Jin; Jung, Hae-Jin; Sobanska, Sophie; Chung, Sang-Gwi; Son, Youn-Suk; Kim, Jo-Chun; Sunwoo, Young; Ro, Chul-Un

2013-11-05

Quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA), known as low-Z particle EPMA, and Raman microspectrometry (RMS) were applied in combination for an analysis of the iron species in airborne PM10 particles collected in underground subway tunnels. Iron species have been reported to be a major chemical species in underground subway particles generated mainly from mechanical wear and friction processes. In particular, iron-containing particles in subway tunnels are expected to be generated with minimal outdoor influence on the particle composition. Because iron-containing particles have different toxicity and magnetic properties depending on their oxidation states, it is important to determine the iron species of underground subway particles in the context of both indoor public health and control measures. A recently developed analytical methodology, i.e., the combined use of low-Z particle EPMA and RMS, was used to identify the chemical species of the same individual subway particles on a single particle basis, and the bulk iron compositions of airborne subway particles were also analyzed by X-ray diffraction. The majority of airborne subway particles collected in the underground tunnels were found to be magnetite, hematite, and iron metal. All the particles collected in the tunnels of underground subway stations were attracted to permanent magnets due mainly to the almost ubiquitous ferrimagnetic magnetite, indicating that airborne subway particles can be removed using magnets as a control measure.

Effect of phosphorus addition on the reductive transformation of pentachlorophenol (PCP) and iron reduction with microorganism involvement.

PubMed

Wang, Yongkui; Liu, Xianli; Huang, Jiexun; Xiao, Wensheng; Zhang, Jiaquan; Yin, Chunqin

2017-10-01

The transformation of phosphorus added to the soil environment has been proven to be influenced by the Fe biochemical process, which thereby may affect the transformation of organic chlorinated contaminants. However, the amount of related literatures regarding this topic is limited. This study aimed to determine the effects of phosphorus addition on pentachlorophenol (PCP) anaerobic transformation, iron reduction, and paddy soil microbial community structure. Results showed that the transformation of phosphorus, iron, and PCP were closely related to the microorganisms. Moreover, phosphorus addition significantly influenced PCP transformation and iron reduction, which promoted and inhibited these processes at low and high concentrations, respectively. Both the maximum reaction rate of PCP transformation and the maximum Fe(II) amount produced were obtained at 1 mmol/L phosphorus concentration. Among the various phosphorus species, dissolved P and NaOH-P considerably changed, whereas only slight changes were observed for the remaining phosphorus species. Microbial community structure analysis demonstrated that adding low concentration of phosphorus promoted the growth of Clostridium bowmanii, Clostridium hungatei, and Clostridium intestinale and Pseudomonas veronii. By contrast, high-concentration phosphorus inhibited growth of these microorganisms, similar to the curves of PCP transformation and iron reduction. These observations indicated that Clostridium and P. veronii, especially Clostridium, played a vital role in the transformation of related substances in the system. All these findings may serve as a reference for the complicated reactions among the multiple components of soils.

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park

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

Kozubal, Mark; Romine, Margaret F.; Jennings, Ryan

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron oxide mats in YNP. Detailed analysis of conserved ribosomal and informational processing genes indicate that the replicate assemblies represent a newmore » phylum-level lineage referred to here as 'novel archaeal group 1 (NAG1)'. The NAG1 organisms contain pathways necessary for the catabolism of peptides and complex carbohydrates as well as a bacterial-like Form I CO dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in metabolism of oxygen including a Type A heme copper oxidase, a bd-type terminal oxidase and a putative oxygen sensing protoglobin. NAG1 has a variety of unique bacterial-like cofactor biosynthesis and transport genes and a Type3-like CRISPR system. Discovery of NAG1 is critical to our understanding of microbial community structure and function in extant thermophilic iron mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogues active in YNP today.« less

Paving a Path to Understanding Metabolic Responses to Iron Bioavailability: Global Proteomic Analysis of Crocosphaera watsonii

NASA Astrophysics Data System (ADS)

Gauglitz, J.; McIlvin, M. R.; Moran, D. M.; Waterbury, J. B.; Saito, M. A.

2016-02-01

Marine diazotrophic cyanobacteria provide a key source of new nitrogen into the oceans and are important contributors to primary production. The geographic distribution of these cyanobacteria is impacted by available iron and phosphorus as well as environmental conditions such as temperature, however available iron concentrations are thought to be particularly critical due to the high demand for iron in cellular processes. Iron bioavailability and microorganismal adaptations to low iron environments may thus play a key role in dictating community structure, however the mechanisms by which cyanobacteria acquire iron and regulate its uptake are not well defined. In this study, the unicellular diazotroph, Crocosphaera watsonii WH8501, was acclimated to a range of bioavailable iron concentrations (from 0.001nM to 8.13nM Fe') using trace metal clean culturing techniques and the proteomes were analyzed by LC/MS-MS. Physiological and proteomic data indicate three distinct phenotypic ranges: iron-replete, iron-limited, and iron-starved. Trends in photosynthetic, carbon fixation and iron storage proteins across the iron gradient indicate that the C. watsonii proteome responds directly to iron availability. Further analysis of relative protein expression, which describes the physiological state of the cell, will lead to insights into how C. watsonii is able to adapt to iron-limited conditions and the resulting biogeochemical implications will be discussed.

Improving Tenth-Grade Students' Five-Paragraph Essay Writing Skills Using Various Writing Strategies, Guided Assignments, and Portfolios for Growth.

ERIC Educational Resources Information Center

Hopkins, Carolyn

This project was implemented and developed to assist low-achieving tenth grade students' essay writing skills. According to examinations administered during the first part of the 2002 school term, many tenth-grade students were not performing on their grade level in regards to the writing process. The overall goal was to have students be able to…

Lyophilization decreases the formation of dialyzable iron by extraction and digestion of chicken breast muscle.

PubMed

Karava, Nilesh B; Mahoney, Raymond R

2011-06-01

We studied the effect of lyophilization of chicken breast muscle on the formation of dialyzable iron from ferric iron. Chicken breast muscle was used chilled, frozen or lyophilized and was analyzed for sulfhydryl and histidine content. It was then homogenized and mixed with ferric iron. The mixture was extracted with acid or digested with pepsin and pancreatin. The extracts and digests were analyzed for dialyzable ferrous and dialyzable total iron and also for protein. In the chilled muscle, similar amounts of dialyzable iron were formed after acid extraction and after proteolytic digestion; however, digestion led to more dialyzable ferrous iron. Freezing had no effect but lyophilization of the homogenized muscle caused large decreases in dialyzable iron and dialyzable ferrous iron for both extraction and digestion processes. Lyophilization also resulted in decreased extraction of peptides, decreased digestion of muscle proteins and reduced levels of sulfhydryl and histidine residues. Our results demonstrate that dialyzable iron is produced both by acid-soluble low molecular weight muscle component(s) and also by peptides resulting from digestion of muscle proteins: both of which reduce and chelate iron. Reduced formation of dialyzable iron by both mechanisms following lyophilization could be explained by sulfhydryl oxidation and impaired digestion due to protein crosslinking.

Investigation of Redox Metal Oxides for Carbonaceous Fuel Conversion and CO2 Capture

NASA Astrophysics Data System (ADS)

Galinsky, Nathan Lee

The chemical looping combustion (CLC) process uses metal oxides, also referred to as oxygen carriers, in a redox scheme for conversion of carbonaceous fuels into a concentrated stream of CO2 and steam while also producing heat and electricity. The unique redox scheme of CLC allows CO2 capture with minimal energy penalty. The CLC process performance greatly depends on the oxygen carrier that is chosen. To date, more than 1000 oxygen carriers have been developed for chemical-looping processes using metal oxides containing first-row transition metals. Oxygen carriers are typically mixed with an inert ceramic support to improve their overall mechanical stability and recyclability. This study focuses on design of (i) iron oxide oxygen carriers for conversion of gaseous carbonaceous fuels and (ii) development of perovskite CaMnO 3-d with improved stability and redox properties for conversion of solid fuels. Iron oxide is cheap and environmentally benign. However, it suffers from low activity with carbonaceous fuels due partially to the low ionic conductivity of iron oxides. In order to address the low activity of iron-oxide-based oxygen carriers, support addition has been shown to lower the energy barrier of oxygen anion transport within the oxygen carrier. This work adds a mixed-ionic-and-electronic-conductor (MIEC) support to iron oxide to help facilitate O2- transport inside the lattice of iron oxide. The MIEC-supported iron oxide is compared to commonly used supports including TiO2 and Al2O 3 and the pure ionic conductor support yttria-stabilized zirconia (YSZ) for conversion of different carbonaceous fuels and hydrogen. Results show that the MIEC-supported iron oxide exhibits up to 70 times higher activity than non-MIEC-supported iron oxides for methane conversion. The MIEC supported iron oxide also shows good recyclability with only minor agglomeration and carbon formation observed. The effect of support-iron oxide synergies is further investigated to understand other physical and chemical properties that lead to highly active and recyclable oxygen carriers. Perovskite and fluorite-structured MIEC supports are tested for conversion of methane. The perovskite supported iron oxides exhibit higher activity and stability resulting from the high mixed conductivity of the support. Fluorite-structured CeO2 oxygen carriers deactivated by 75% after 10 redox cycles. This deactivation was attributed to agglomeration of iron oxide. The agglomeration was determined to occur due to Fe x+ transport during the oxidation step leading to high content of Fe on the surface of the oxygen carrier. Besides the MIEC supports, inert MgAl2O4 supported iron oxide is observed to activate in methane. The activation is attributed to carbon formation causing physical degradation of the oxygen carrier and leading to higher surface area and porosity. To achieve high activity with solid fuels, chemical looping with oxygen uncoupling (CLOU) is commonly used. This process uses oxygen carriers with high PO2 that allows the oxygen carrier to release a portion of their lattice oxygen as gaseous oxygen. In turn, the gaseous oxygen can react with solid fuel particles at a higher rate than the lattice oxygen. CaMnO 3 perovskite oxygen carriers offer high potential for CLOU. However, pure CaMnO3 suffers from long-term recyclability and sulfur poisoning. Addition of A-site (Ba and Sr) and B-site (Fe, Ni, Co, Al, and V) dopants are used to improve the performance of the base CaMnO3 oxygen carrier. Sr (A-site) and Fe (B-site) exhibit high compatibility with the base perovskite structure. Both dopants observe oxygen uncoupling properties up to 200°C below that of pure CaMnO3. Additionally, the doped structures also exhibit higher stability at high temperatures (>1000°C) and during redox cycles. The doped oxygen carriers also demonstrate significantly improved activity for coal char conversion.

Removal of Iron and Manganese in Groundwater using Natural Biosorbent

NASA Astrophysics Data System (ADS)

Baharudin, F.; Tadza, M. Y. Mohd; Imran, S. N. Mohd; Jani, J.

2018-04-01

This study was conducted to measure and compare the concentration of iron, manganese and hardness of the river and groundwater and to determine the effectiveness of iron and manganese removal by using natural biosorbent which is banana peels. The samples of river and groundwater were collected at riverbank filtration site at Jenderam Hilir, Dengkil. Based on the water quality investigation, the concentration of iron and manganese in the samples of groundwater have exceeded the drinking water quality standard which are 0.3 mg/L for iron and 0.1 mg/L for manganese. The removal process of the iron and manganese in the groundwater was done by using 2, 4 and 8 grams of banana peels activated carbon. It is found that with higher amount of activated banana peels, the removal of iron and manganese is more effective. The ranges of percentage of iron and manganese removal are between 82.25% to 90.84% and 98.79% to 99.43% respectively. From the result, banana peels activated carbon can be concluded as a one of the most effective low-cost adsorbent for groundwater treatment.

40 CFR 421.226 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... molybdenum produced Arsenic 27.120 12.097 Chromium 7.219 2.927 Lead 5.463 2.536 Nickel 10.731 7.219 Iron 23... technical grade molybdenum plus vanadium plus pure grade molybdenum produced Arsenic 80.952 36.108 Chromium...] [Reserved] Ammonia (as N) 24114.000 10600.000 (c) Vanadium decomposition wet air pollution control. PSNS for...

40 CFR 421.226 - Pretreatment standards for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... molybdenum produced Arsenic 27.120 12.097 Chromium 7.219 2.927 Lead 5.463 2.536 Nickel 10.731 7.219 Iron 23... technical grade molybdenum plus vanadium plus pure grade molybdenum produced Arsenic 80.952 36.108 Chromium...] [Reserved] Ammonia (as N) 24114.000 10600.000 (c) Vanadium decomposition wet air pollution control. PSNS for...

Mercury mine drainage and processes that control its environmental impact

USGS Publications Warehouse

Rytuba, J.J.

2000-01-01

Mine drainage from mercury mines in the California Coast Range mercury mineral belt is an environmental concern because of its acidity and high sulfate, mercury, and methylmercury concentrations. Two types of mercury deposits are present in the mineral belt, silica-carbonate and hot-spring type. Mine drainage is associated with both deposit types but more commonly with the silica-carbonate type because of the extensive underground workings present at these mines. Mercury ores consisting primarily of cinnabar were processed in rotary furnaces and retorts and elemental mercury recovered from condensing systems. During the roasting process mercury phases more soluble than cinnabar are formed and concentrated in the mine tailings, commonly termed calcines. Differences in mineralogy and trace metal geochemistry between the two deposit types are reflected in mine drainage composition. Silica-carbonate type deposits have higher iron sulfide content than hot- spring type deposits and mine drainage from these deposits may have extreme acidity and very high concentrations of iron and sulfate. Mercury and methylmercury concentrations in mine drainage are relatively low at the point of discharge from mine workings. The concentration of both mercury species increases significantly in mine drainage that flows through and reacts with calcines. The soluble mercury phases in the calcines are dissolved and sulfate is added such that methylation of mercury by sulfate reducing bacteria is enhanced in calcines that are saturated with mine drainage. Where mercury mine drainage enters and first mixes with stream water, the addition of high concentrations of mercury and sulfate generates a favorable environment for methylation of mercury. Mixing of oxygenated stream water with mine drainage causes oxidation of dissolved iron(II) and precipitation of iron oxyhydroxide that accumulates in the streambed. Both mercury and methylmercury are strongly adsorbed onto iron oxyhydroxide over the pH range of 3.2-7.1 in streams impacted by mine drainage. The dissolved fraction of both mercury species is depleted and concentrated in iron oxyhydroxide such that the amount of iron oxyhydroxide in the water column reflects the concentration of mercury species. In streams impacted by mine drainage, mercury and methylmercury are transported and adsorbed onto particulate phases. During periods of low stream flow, fine-grained iron hydroxide sediment accumulates in the bed load of the stream and adsorbs mercury and methylmercury such that both forms of mercury become highly enriched in the iron oxyhydroxide sediment. During high-flow events, mercury- and methylmercury-enriched iron hydroxide sediment is transported into larger aquatic systems producing a high flux of bioavailable mercury. (C) 2000 Elsevier Science B.V.

Hidden values in bauxite residue (red mud): Recovery of metals

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

Liu, Yanju; Naidu, Ravi, E-mail: ravi.naidu@unisa.edu.au

Highlights: • Current iron recovery techniques using red mud are depicted. • Advantages and disadvantages exist in different recovering processes. • Economic and environmental friendly integrated usage of red mud is promising. - Abstract: Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially.more » Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud.« less

Measuring “Free” Iron Levels in Caenorhabditis Elegans Using Low-Temperature Fe(III) Electron Paramagnetic Resonance Spectroscopy

PubMed Central

Pate, Kira T.; Rangel, Natalie A.; Fraser, Brian; Clement, Matthew H. S.; Srinivasan, Chandra

2007-01-01

Oxidative stress, caused by free radicals within the body, has been associated with the process of aging and many human diseases. As free radicals, in particular superoxide, are difficult to measure, an alternative indirect method for measuring oxidative stress levels has been successfully used in E. coli and yeast. This method is based on a proposed connection between elevated superoxide levels and release of iron from solvent exposed [4Fe-4S] enzyme clusters, which eventually leads to an increase in hydroxyl radical production. In past studies using bacteria and yeast, a positive correlation was found between superoxide production or oxidative stress due to superoxide within the organism and EPR (electron paramagnetic resonance) detectable “free” iron levels. In the present study, we have developed a reliable and an efficient method for measuring “free” iron levels in C. elegans using low temperature Fe(III) EPR at g = 4.3. This method utilizes synchronized worm cultures grown on plates, which are homogenized and treated with desferrioxamine, an Fe(III) chelator, prior to packing the EPR tube. Homogenization was found not to alter “free” iron levels, while desferrioxamine treatment significantly raised these levels, indicating presence of both Fe(II) and Fe(III) in the “free” iron pool. The correlation between free radical levels and the observed “free” iron levels was examined by using heat stress and paraquat treatment. The intensity of the Fe(III) EPR signal and thus, the concentration of the “free” iron pool, varied with the treatments that altered radical levels without changing the total iron levels. This study provides the groundwork needed to uncover the correlation between oxidative stress, “free” iron levels, and longevity in C. elegans. PMID:17010298

Analysis of holding time variations to Ni and Fe content and morphology in nickel laterite limonitic reduction process by using coal-dolomite bed

NASA Astrophysics Data System (ADS)

Abdul, Fakhreza; Pintowantoro, Sungging; Yuwandono, Ridwan Bagus

2018-04-01

With the depletion of nickel sulfide ore resources, the nickel laterit processing become an attention to fulfill nickel world demans. Reducing laterite nickel by using a low cost carbonaceous reductan has proved produces high grade ferronickel alloy. In this research, reduction was carried out to low grade laterite nickel (limonite) with 1.25% nikel content by using CO gas reductant formed by reaction between coal and dolomite. Reduction process preceded by forming brickets mixture from limonit ore, coal, and Na2SO4, then the brickets placed inside crucible bed together with dolomit and reduced at temperature 1400 °C with holding time variations 4, 6, and 8 hours. EDX, XRD, and SEM test were carried out to find out the Ni and nickel grade after reduced, the phases that formed, and the morphology brickets after reduced. The reduction results shows that the highest increase on nickel grade was obtained by 8 hours holding time increasing 5.84 % from initial grade, and the highest recovery was obtained by 6 hours holding time with recovery 88.51 %. While the higest increase on Fe grade was obtained by 4 hours holding time, and the highest recovery Fe was obtained by 4 hours holding time with recovery 85.41%.

Caries prevalence and manganese and iron levels of drinking water in school children living in a rural/semi-urban region of North-Eastern Greece.

PubMed

Tsanidou, Eirini; Nena, Evangelia; Rossos, Alexandros; Lendengolts, Zhanna; Nikolaidis, Christos; Tselebonis, Athanasios; Constantinidis, Theodoros C

2015-11-01

The aim of this study was to correlate different combinations of manganese (Mn) and iron (Fe) concentration in drinking water with prevalence of dental caries in both primary and permanent dentition, among school children with similar socio-demographic characteristics. Evros region, in North-Eastern Greece, was divided into four areas, according to combinations of levels of Mn and Fe in drinking water (High Mn-high Fe; High Mn-low Fe; Low Mn-high Fe; Low Mn-low Fe). Children of similar socio-economic background, attending either first or sixth grade (primary or permanent dentition, respectively) of elementary schools, were clinically assessed for caries by three dentists. Caries was defined by the use of dmft/DMFT index. A questionnaire answered by the parents was also analysed. 573 children were included. Caries prevalence was high in both age groups (64.2 % with mean dmft 3.3 ± 3.6 in primary and 60.7 % with mean DMFT 2.3 ± 2.5 in permanent dentition, respectively). Residence in a high Mn-low Fe area was associated with a significant OR for caries in both age groups [OR (95 % CIs) for primary and permanent dentition was, respectively, 3.75 (1.68-8.37), p = 0.001 and 3.09 (1.48-6.44), p = 0.003], independently of factors like sugar consumption or brushing frequency. Prevalence of caries was high in general, and was associated with the combination of high Mn/low Fe levels in drinking water, independently of various socio-demographic factors.

Interaction of inorganic anions with iron-mineral adsorbents in aqueous media--a review.

PubMed

Kumar, Eva; Bhatnagar, Amit; Hogland, William; Marques, Marcia; Sillanpää, Mika

2014-01-01

A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pHpzc, purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology. © 2013.

Impact on the Fe redox cycling of organic ligands released by Synechococcus PCC 7002, under different iron fertilization scenarios. Modeling approach

NASA Astrophysics Data System (ADS)

Samperio-Ramos, Guillermo; González-Dávila, Melchor; Santana-Casiano, J. Magdalena

2018-06-01

The kinetics of Fe redox transformations are of crucial importance in determining the bioavailability of iron, due to inorganic Fe(II) and Fe weakly organic complexes being the most easily assimilated species by phytoplankton. The role played by the natural organic ligands excreted by the cyanobacteria Synecococcus PCC 7002 on the iron redox chemistry was studied at different stages of growth, considering changes in the organic exudation of the cyanobacteria, associated with growth under two different scenarios of iron availability. The oxidation/reduction processes of iron were studied at nanomolar levels and under different physicochemical conditions of pH (7.2- 8.2), temperature (5- 35 °C) and salinity (10- 37). The presence of natural organic exudates of Synechococcus affected the redox behavior of iron. A pH-dependent and photo-induced Fe(III) reduction process was detected in the presence of exudates produced under Fe-Low conditions. Photolytic reactions also modified the reactivity of those exudates with respect to Fe(II), increasing its lifetime in seawater. Without light mediated processes, organic ligands excreted under iron deficient conditions intensified the Fe(II) oxidation at pH < 7.5. The organic exudates released under High-Fe conditions retarded the Fe(II) oxidation rate, as a function of DOC produced. The changes in the apparent oxidation rate were fitted to polynomial functions for both of the Fe-scenarios considered. A kinetic modeling approach to describe the speciation and the contribution of individual Fe(II) species to the overall oxidation rate was applied, considering the experimental data and delimiting the equilibrium and redox constants between iron and the major ligands present in solution. Two organic type ligands for the exudates of Synechococcus PCC 7002, with different iron-chelation properties were included in the model. The Fe(II) speciation was radically affected when organic ligands were considered. The individual contributions to the overall Fe(II) oxidation rate demonstrated that these organic ligands played a key role in the oxidation process, although their contributions were dependent on the prescribed iron conditions. The study, therefore, suggests that the variability in the composition and nature of organic exudates released, due to iron availability conditions, might determine the redox behaviour of iron in seawater.

A TiO2 abundance map for the northern maria

NASA Technical Reports Server (NTRS)

Johnson, T. V.; Saunders, R. S.; Matson, D. L.; Mosher, J. A.

1977-01-01

A map of TiO2 abundance for most of the northern maria is presented. The telescopic data base used is the 0.38/0.56-micron ratio mosaic from Johnson et at. (1977). The titanium content has been estimated using the correlation established by Charette et al. (1974). The combination of observational, processing, and calibration errors indicates that the TiO2 map is accurate to + or - 2% (wt% TiO2) for high TiO2 content (more than 5%) and + or - 1% for low values of TiO2. Analysis of the lunar sample and telescopic data suggests strongly that the spectral parameter mapped is sensitive primarily to TiO2 abundance in the range 3-9% and does not correlate directly with iron content. It is suggested, however, that for the low TiO2 mare regions (less than 2-3% TiO2) there may be a relation between the spectral ratio and iron content and that some of the reddest mare areas in the Imbrium region may have low iron contents as well as low titanium abundances.

Efficient degradation of Acid Orange 7 in aqueous solution by iron ore tailing Fenton-like process.

PubMed

Zheng, Jianming; Gao, Zhanqi; He, Huan; Yang, Shaogui; Sun, Cheng

2016-05-01

An effective method based on iron ore tailing Fenton-like process was studied for removing an azo dye, Acid Orange 7 (AO7) in aqueous solution. Five tailings were characterized by X-ray fluorescence spectroscope (XFS), Brunner-Emmet-Teller (BET) measurement, and Scanning Electron Microscope (SEM). The result of XFS showed that Fe, Si and Ca were the most abundant elements and some toxic heavy metals were also present in the studied tailings. The result of BET analysis indicated that the studied tailings had very low surface areas (0.64-5.68 m(2) g(-1)). The degradation efficiencies of AO7 were positively correlated with the content of iron oxide and cupric oxide, and not related with the BET surface area of the tailings. The co-existing metal elements, particularly Cu, might accelerate the heterogeneous Fenton-like reaction. The effects of other parameters on heterogeneous Fenton-like degradation of AO7 by a converter slag iron tailing (tailing E) which contains highest iron oxide were also investigated. The tailing could be reused 10 times without significant decrease of the catalytic capacity. Very low amount of iron species and almost undetectable toxic elements were leached in the catalytic degradation of AO7 by the tailing E. The reaction products were identified by gas chromatography-mass spectrometry and a possible pathway of AO7 degradation was proposed. This study not only provides an effective method for removing azo dyes in polluted water by employing waste tailings as Fenton-like catalysts, but also uses waste tailings as the secondary resource. Copyright © 2016 Elsevier Ltd. All rights reserved.

The evaluation of lumbosacral dysplasia in young patients with lumbosacral spondylolisthesis: comparison with controls and relationship with the severity of slip.

PubMed

Pawar, Abhijit; Labelle, Hubert; Mac-Thiong, Jean-Marc

2012-11-01

Comparison of lumbosacral dysplasia between normal individuals and patients with low and high grade spondylolisthesis has not been done previously. The objective of this study is to evaluate the relationship between lumbosacral dysplasia and severity of slip in young patients with lumbosacral spondylolisthesis. Postero-anterior and lateral radiographs of 120 normal individuals and 131 patients with developmental spondylolisthesis (91 low and 40 high grades) were reviewed. Quantitative evaluation of lumbosacral dysplasia was done using 6 criteria involving the degree of laminar dysplasia, degree of facet dysplasia, size of L5 transverse processes, L5/S1 disc height, type of sacral doming and L5 lumbar index. Subjects were categorized as having no/low, moderate or severe dysplasia based on the total dysplasia score. Comparisons in total dysplasia score between normal, low grade and high grade groups were performed and the correlation between degree of dysplasia and percentage of slip was assessed. Most normal individuals (88.3%) had no/low dysplasia; most patients with low grade spondylolisthesis (61.5%) had moderate dysplasia, while most patients with high grade spondylolisthesis (72.5%) had severe dysplasia. There was a significant difference in dysplasia between normal individuals and patients with spondylolisthesis. Dysplasia also varied significantly between low and high grade spondylolisthesis. There was a strong positive correlation (r = 0.63) between severity of dysplasia and percentage of slip. There is a significant relationship between the severity of spondylolisthesis and lumbosacral dysplasia, with mainly no/low dysplasia observed in controls and increasing total dysplasia scores in higher grades of spondylolisthesis. In addition, a variable degree of dysplasia was found within groups with low or high grade spondylolisthesis, suggesting that different subgroups of patients exist with regard to dysplasia. Thus the degree of dysplasia varies in spondylolisthesis and it is possible that different grades of dysplasia could relate to different prognoses or outcomes with treatment.

Preliminary report on iron ore reserves at Bomi Hills, Liberia

USGS Publications Warehouse

Newhouse, Walter H.; Thayer, Thomas P.; Butler, Arthur P.

1945-01-01

At the request if the Liberian Government made through the Department of State of the United States Government, a party of geologists of the Geological Survey, United States Department of the Interior, was sent to Liberia to examine certain mineral deposits. The party, consisting of Walter H. Newhouse, Thomas P. Thayer, and Arthur P. Butler, Jr., left Washington, D.C., about December 1, 1943, and arrived in Monrovia, Liberia, December 12, 1943. They left Roberts Field, Liberia, May 5, 1944, and returned to Washington May 16, 1944. The geologists left Monrovia for field work in the interior on January 9, the delay of several weeks being due to difficulties in obtaining porters. Mr. Arthur Sherman, Mining Engineer for the Liberian Government, who accompanied the party into the interior, capably participated in the examination of the iron deposits and otherwise rendered invaluable assistance sue to his extensive knowledge of the native tribes and trails. President Tubman requested that the part first examined the iron deposits at Bomi Hills. At the close of the work there he requested that iron deposits in the Kpandemai Mountains be investigated. The party therefore left Bomi Hills on March 25 and arrived at Jordense Camp in the Kpandemai Mountain region on April 6. Four days were spent at this place examining the iron mineralization in the vicinity of Castle Rock, Sugar Loaf, and Mt. Wutivi of Kpandemai Mountains. On April 11 Kpandemai village reached. One day was spent on a long transverse into the Kpandemai Mountains to investigate the iron mineralization. The party left Kpandemai Village April 15 and arrived at Monrovia April 27. The iron mineralization in the portions of the Kpandemai Mountains investigated by the party is believed to be too low in grade and too small in amount to be of any present commercial interest and will not be considered further in this report.

Ex vivo assessment of polyol coated-iron oxide nanoparticles for MRI diagnosis applications: toxicological and MRI contrast enhancement effects

NASA Astrophysics Data System (ADS)

Bomati-Miguel, Oscar; Miguel-Sancho, Nuria; Abasolo, Ibane; Candiota, Ana Paula; Roca, Alejandro G.; Acosta, Milena; Schwartz, Simó; Arus, Carles; Marquina, Clara; Martinez, Gema; Santamaria, Jesus

2014-03-01

Polyol synthesis is a promising method to obtain directly pharmaceutical grade colloidal dispersion of superparamagnetic iron oxide nanoparticles (SPIONs). Here, we study the biocompatibility and performance as T2-MRI contrast agents (CAs) of high quality magnetic colloidal dispersions (average hydrodynamic aggregate diameter of 16-27 nm) consisting of polyol-synthesized SPIONs (5 nm in mean particle size) coated with triethylene glycol (TEG) chains (TEG-SPIONs), which were subsequently functionalized to carboxyl-terminated meso-2-3-dimercaptosuccinic acid (DMSA) coated-iron oxide nanoparticles (DMSA-SPIONs). Standard MTT assays on HeLa, U87MG, and HepG2 cells revealed that colloidal dispersions of TEG-coated iron oxide nanoparticles did not induce any loss of cell viability after 3 days incubation with dose concentrations below 50 μg Fe/ml. However, after these nanoparticles were functionalized with DMSA molecules, an increase on their cytotoxicity was observed, so that particles bearing free terminal carboxyl groups on their surface were not cytotoxic only at low concentrations (<10 μg Fe/ml). Moreover, cell uptake assays on HeLa and U87MG and hemolysis tests have demonstrated that TEG-SPIONs and DMSA-SPIONs were well internalized by the cells and did not induce any adverse effect on the red blood cells at the tested concentrations. Finally, in vitro relaxivity measurements and post mortem MRI studies in mice indicated that both types of coated-iron oxide nanoparticles produced higher negative T2-MRI contrast enhancement than that measured for a similar commercial T2-MRI CAs consisting in dextran-coated ultra-small iron oxide nanoparticles (Ferumoxtran-10). In conclusion, the above attributes make both types of as synthesized coated-iron oxide nanoparticles, but especially DMSA-SPIONs, promising candidates as T2-MRI CAs for nanoparticle-enhanced MRI diagnosis applications.

Pop III i-process nucleosynthesis and the elemental abundances of SMSS J0313-6708 and the most iron-poor stars

NASA Astrophysics Data System (ADS)

Clarkson, O.; Herwig, F.; Pignatari, M.

2018-02-01

We have investigated a highly energetic H-ingestion event during shell He burning leading to H-burning luminosities of log (LH/L⊙) ˜ 13 in a 45 M⊙ Pop III massive stellar model. In order to track the nucleosynthesis which may occur in such an event, we run a series of single-zone nucleosynthesis models for typical conditions found in the stellar evolution model. Such nucleosynthesis conditions may lead to i-process neutron densities of up to ˜1013 cm-3. The resulting simulation abundance pattern, where Mg comes from He burning and Ca from the i process, agrees with the general observed pattern of the most iron-poor star currently known, SMSS J031300.36-670839.3. However, Na is also efficiently produced in these i-process conditions, and the prediction exceeds observations by ˜2.5 dex. While this probably rules out this model for SMSS J031300.36-670839.3, the typical i-process signature of combined He burning and i process of higher than solar [Na/Mg], [Mg/Al], and low [Ca/Mg] is reproducing abundance features of the two next most iron-poor stars HE 1017-5240 and HE 1327-2326 very well. The i process does not reach Fe which would have to come from a low level of additional enrichment. i process in hyper-metal-poor or Pop III massive stars may be able to explain certain abundance patterns observed in some of the most metal-poor CEMP-no stars.

A Technological Comparison of Six Processes for the Production of Reduction-Grade Alumina from Non-Bauxitic Raw Materials

NASA Astrophysics Data System (ADS)

Bengtson, K. B.

The U. S. Bureau of Mines, by means of a contract with Kaiser Engineers and with Kaiser Aluminum & Chemical Corporation as a subcontractor, has sponsored a technological and an economic evaluation of six candidate processes for the manufacture of alumina from certain U. S. raw materials other than bauxite. This paper describes each process. Flow diagrams and the total energy requirement for each process are included. Important characteristics affecting the economics of producing alumina by each process are discussed, and some presently unsolved technical problems are identified. The extraction of alumina from clay via hydrochloric acid with iron separation by solvent extraction, and the crystallization of intermediate AlCl3·6H2O through the introduction of HCl gas into the pregnant mother liquor, appears to be technically feasible and the most attractive of the six raw material/process combinations.

New technology for low-grade hardwood utilization: System 6

Treesearch

Hugh W. Reynolds; Charles J. Gatchell

1982-01-01

System 6 is a technology for converting low-grade hardwood to high-valued end products such as furniture and kitchen cabinets. Among its concepts are: (1) a new, nonlumber product called standard-size blanks; (2) highly automated methods of converting the logs to blanks; (3) total processing of every board that contains a minimum-size cutting; and (4) minimized machine...

Enhanced erythropoiesis in Hfe-KO mice indicates a role for Hfe in the modulation of erythroid iron homeostasis

PubMed Central

Ramos, Pedro; Guy, Ella; Chen, Nan; Proenca, Catia C.; Gardenghi, Sara; Casu, Carla; Follenzi, Antonia; Van Rooijen, Nico; Grady, Robert W.; de Sousa, Maria

2011-01-01

In hereditary hemochromatosis, mutations in HFE lead to iron overload through abnormally low levels of hepcidin. In addition, HFE potentially modulates cellular iron uptake by interacting with transferrin receptor, a crucial protein during erythropoiesis. However, the role of HFE in this process was never explored. We hypothesize that HFE modulates erythropoiesis by affecting dietary iron absorption and erythroid iron intake. To investigate this, we used Hfe-KO mice in conditions of altered dietary iron and erythropoiesis. We show that Hfe-KO mice can overcome phlebotomy-induced anemia more rapidly than wild-type mice (even when iron loaded). Second, we evaluated mice combining the hemochromatosis and β-thalassemia phenotypes. Our results suggest that lack of Hfe is advantageous in conditions of increased erythropoietic activity because of augmented iron mobilization driven by deficient hepcidin response. Lastly, we demonstrate that Hfe is expressed in erythroid cells and impairs iron uptake, whereas its absence exclusively from the hematopoietic compartment is sufficient to accelerate recovery from phlebotomy. In summary, we demonstrate that Hfe influences erythropoiesis by 2 distinct mechanisms: limiting hepcidin expression under conditions of simultaneous iron overload and stress erythropoiesis, and impairing transferrin-bound iron uptake by erythroid cells. Moreover, our results provide novel suggestions to improve the treatment of hemochromatosis. PMID:21059897

Iron isotope fractionation during hydrothermal ore deposition and alteration

NASA Astrophysics Data System (ADS)

Markl, Gregor; von Blanckenburg, Friedhelm; Wagner, Thomas

2006-06-01

Iron isotopes fractionate during hydrothermal processes. Therefore, the Fe isotope composition of ore-forming minerals characterizes either iron sources or fluid histories. The former potentially serves to distinguish between sedimentary, magmatic or metamorphic iron sources, and the latter allows the reconstruction of precipitation and redox processes. These processes take place during ore formation or alteration. The aim of this contribution is to investigate the suitability of this new isotope method as a probe of ore-related processes. For this purpose 51 samples of iron ores and iron mineral separates from the Schwarzwald region, southwest Germany, were analyzed for their iron isotope composition using multicollector ICP-MS. Further, the ore-forming and ore-altering processes were quantitatively modeled using reaction path calculations. The Schwarzwald mining district hosts mineralizations that formed discontinuously over almost 300 Ma of hydrothermal activity. Primary hematite, siderite and sulfides formed from mixing of meteoric fluids with deeper crustal brines. Later, these minerals were partly dissolved and oxidized, and secondary hematite, goethite and iron arsenates were precipitated. Two types of alteration products formed: (1) primary and high-temperature secondary Fe minerals formed between 120 and 300 °C, and (2) low-temperature secondary Fe minerals formed under supergene conditions (<100 °C). Measured iron isotope compositions are variable and cover a range in δ56Fe between -2.3‰ and +1.3‰. Primary hematite ( δ56Fe: -0.5‰ to +0.5‰) precipitated by mixing oxidizing surface waters with a hydrothermal fluid that contained moderately light Fe ( δ56Fe: -0.5‰) leached from the crystalline basement. Occasional input of CO 2-rich waters resulted in precipitation of isotopically light siderite ( δ56Fe: -1.4 to -0.7‰). The difference between hematite and siderite is compatible with published Fe isotope fractionation factors. The observed range in isotopic compositions can be accounted for by variable fractions of Fe precipitating from the fluid. Therefore, both fluid processes and mass balance can be inferred from Fe isotopes. Supergene weathering of siderite by oxidizing surface waters led to replacement of isotopically light primary siderite by similarly light secondary hematite and goethite, respectively. Because this replacement entails quantitative transfer of iron from precursor mineral to product, no significant isotope fractionation is produced. Hence, Fe isotopes potentially serve to identify precursors in ore alteration products. Goethites from oolitic sedimentary iron ores were also analyzed. Their compositional range appears to indicate oxidative precipitation from relatively uniform Fe dissolved in coastal water. This comprehensive iron isotope study illustrates the potential of the new technique in deciphering ore formation and alteration processes. Isotope ratios are strongly dependent on and highly characteristic of fluid and precipitation histories. Therefore, they are less suitable to provide information on Fe sources. However, it will be possible to unravel the physico-chemical processes leading to the formation, dissolution and redeposition of ores in great detail.

Treatment of antimony mine drainage: challenges and opportunities with special emphasis on mineral adsorption and sulfate reducing bacteria.

PubMed

Li, Yongchao; Hu, Xiaoxian; Ren, Bozhi

2016-01-01

The present article summarizes antimony mine distribution, antimony mine drainage generation and environmental impacts, and critically analyses the remediation approach with special emphasis on iron oxidizing bacteria and sulfate reducing bacteria. Most recent research focuses on readily available low-cost adsorbents, such as minerals, wastes, and biosorbents. It is found that iron oxides prepared by chemical methods present superior adsorption ability for Sb(III) and Sb(V). However, this process is more costly and iron oxide activity can be inhibited by plenty of sulfate in antimony mine drainage. In the presence of sulfate reducing bacteria, sulfate can be reduced to sulfide and form Sb(2)S(3) precipitates. However, dissolved oxygen and lack of nutrient source in antimony mine drainage inhibit sulfate reducing bacteria activity. Biogenetic iron oxide minerals from iron corrosion by iron-oxidizing bacteria may prove promising for antimony adsorption, while the micro-environment generated from iron corrosion by iron oxidizing bacteria may provide better growth conditions for symbiotic sulfate reducing bacteria. Finally, based on biogenetic iron oxide adsorption and sulfate reducing bacteria followed by precipitation, the paper suggests an alternative treatment for antimony mine drainage that deserves exploration.

Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release.

PubMed

Hedberg, Y; Wang, X; Hedberg, J; Lundin, M; Blomberg, E; Wallinder, I Odnevall

2013-04-01

Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

Paired Straight Hearth Furnace - Transformational Ironmaking Process

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

Lu, Wei-Kao; Debski, Paul

2014-11-19

The U. S. steel industry has reduced its energy intensity per ton of steel shipped by 33% since 1990. However, further significant gains in energy efficiency will require the development of new, transformational iron and steelmaking processes. The Paired Straight Hearth Furnace (PSH) process is an emerging alternative high productivity, direct reduced iron (DRI) technology that may achieve very low fuel rates and has the potential to replace blast furnace ironmaking. The PSH furnace can operate independently or may be coupled with other melting technologies to produce liquid hot metal that is both similar to blast furnace iron and suitablemore » as a feedstock for basic oxygen steelmaking furnaces. The PSH process uses non-metallurgical coal as a reductant to convert iron oxides such as iron ore and steelmaking by-product oxides to DRI pellets. In this process, a multi-layer, nominally 120mm tall bed of composite “green balls” made from oxide, coal and binder is built up and contained within a moving refractory hearth. The pellet bed absorbs radiant heat energy during exposure to the high temperature interior refractory surfaces of the PSH while generating a strongly reducing gas atmosphere in the bed that yields a highly metalized DRI product. The PSH concept has been well tested in static hearth experiments. A moving bed design is being developed. The process developers believe that if successful, the PSH process has the potential to replace blast furnaces and coke ovens at a fraction of the operating and capital cost while using about 30% less energy relative to current blast furnace technology. DRI output could also feed electric arc furnaces (EAFs) by displacing a portion of the scrap charge.« less

Quantitating Iron in Serum Ferritin by Use of ICP-MS

NASA Technical Reports Server (NTRS)

Smith, Scott M.; Gillman, Patricia L.

2003-01-01

A laboratory method has been devised to enable measurement of the concentration of iron bound in ferritin from small samples of blood (serum). Derived partly from a prior method that depends on large samples of blood, this method involves the use of an inductively-coupled-plasma mass spectrometer (ICP-MS). Ferritin is a complex of iron with the protein apoferritin. Heretofore, measurements of the concentration of serum ferritin (as distinguished from direct measurements of the concentration of iron in serum ferritin) have been used to assess iron stores in humans. Low levels of serum ferritin could indicate the first stage of iron depletion. High levels of serum ferritin could indicate high levels of iron (for example, in connection with hereditary hemochromatosis an iron-overload illness that is characterized by progressive organ damage and can be fatal). However, the picture is complicated: A high level of serum ferritin could also indicate stress and/or inflammation instead of (or in addition to) iron overload, and low serum iron concentration could indicate inflammation rather than iron deficiency. Only when concentrations of both serum iron and serum ferritin increase and decrease together can the patient s iron status be assessed accurately. Hence, in enabling accurate measurement of the iron content of serum ferritin, the present method can improve the diagnosis of the patient s iron status. The prior method of measuring the concentration of iron involves the use of an atomic-absorption spectrophotometer with a graphite furnace. The present method incorporates a modified version of the sample- preparation process of the prior method. First, ferritin is isolated; more specifically, it is immobilized by immunoprecipitation with rabbit antihuman polyclonal antibody bound to agarose beads. The ferritin is then separated from other iron-containing proteins and free iron by a series of centrifugation and wash steps. Next, the ferritin is digested with nitric acid to extract its iron content. Finally, a micronebulizer is used to inject the sample of the product of the digestion into the ICPMS for analysis of its iron content. The sensitivity of the ICP-MS is high enough to enable it to characterize samples smaller than those required in the prior method (samples can be 0.15 to 0.60 mL).

Adsorption of Free Fatty Acid (FFA) in Low-Grade Cooking Oil Used Activated Natural Zeolite as Adsorbent

NASA Astrophysics Data System (ADS)

Larasati Tres Ayu Putranti, Monika; Kompiang Wirawan, Sang; Made Bendiyasa, I.

2018-01-01

Adsorption of free fatty acid (FFA) in low-grade cooking oil using active natural zeolite adsorbent was done as an effort to improve the quality of low-grade cooking oil so that it can fulfill the standard of fried oil which has been set on SNI 01-3741-2013. Adsorption was carried out with natural zeolite which activated with HCl and NaOH solution followed by the calcination process. The results showed that the NaOH activated zeolite decreased FFA content in low-grade cooking oil more than the HCl activated natural zeolite, with optimum NaOH concentration was 0.75 M. In the adsorption equilibrium analysis with temperature variation (25 °C, 40 °C, 80 °C ), obtained that adsorption of FFA with NaOH activated natural zeolite follows Adsorption Isotherm Freundlich Model with equilibrium constant value was 20,5873; 0,9629 dan 0,8053.

Clinical Impact and Cellular Mechanisms of Iron Overload-Associated Bone Loss

PubMed Central

Jeney, Viktória

2017-01-01

Diseases/conditions with diverse etiology, such as hemoglobinopathies, hereditary hemochromatosis and menopause, could lead to chronic iron accumulation. This condition is frequently associated with a bone phenotype; characterized by low bone mass, osteoporosis/osteopenia, altered microarchitecture and biomechanics, and increased incidence of fractures. Osteoporotic bone phenotype constitutes a major complication in patients with iron overload. The purpose of this review is to summarize what we have learnt about iron overload-associated bone loss from clinical studies and animal models. Bone is a metabolically active tissue that undergoes continuous remodeling with the involvement of osteoclasts that resorb mineralized bone, and osteoblasts that form new bone. Growing evidence suggests that both increased bone resorption and decreased bone formation are involved in the pathological bone-loss in iron overload conditions. We will discuss the cellular and molecular mechanisms that are involved in this detrimental process. Fuller understanding of this complex mechanism may lead to the development of improved therapeutics meant to interrupt the pathologic effects of excess iron on bone. PMID:28270766

[Methodological aspects of evaluation of potential lipid capacity for peroxidation from the serum levels of TBA-active products during iron ion stimulation].

PubMed

Kulikova, A I; Tugusheva, F A; Zubina, I M; Shepilova, I N

2008-05-01

The authors propose a simple and reproducible procedure for using iron ions to stimulate serum lipid peroxidation, with TBA-active products being further determined. The procedure determines the reserve of lipids that can be oxidized during oxidative stress. A combination of direct studies and correlation analysis suggests that low-density lipoproteins and very low-density lipoproteins are the major substrates for lipid peroxidation while high-density lipoproteins show a high resistance to this process. The presented procedure may be used to monitor lipid peroxidation in various conditions and upon various exposures in common laboratory practice.

Optimal copper supply is required for normal plant iron deficiency responses

PubMed Central

Waters, Brian M; Armbrust, Laura C

2013-01-01

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity. PMID:24084753

Optimal copper supply is required for normal plant iron deficiency responses.

PubMed

Waters, Brian M; Armbrust, Laura C

2013-01-01

Iron (Fe) and copper (Cu) homeostasis are tightly linked across biology. Understanding crosstalk between Fe and Cu nutrition could lead to strategies for improved growth on soils with low or excess metals, with implications for agriculture and phytoremediation. Here, we show that Cu and Fe nutrition interact to increase or decrease Fe and/or Cu accumulation in leaves and Fe uptake processes. Leaf Cu concentration increased under low Fe supply, while high Cu lowered leaf Fe concentration. Ferric reductase activity, an indicator of Fe demand, was inhibited at insufficient or high Cu supply. Surprisingly, plants grown without Fe were more susceptible to Cu toxicity.

Differentiated planetesimal impacts into a terrestrial magma ocean: Fate of the iron core

NASA Astrophysics Data System (ADS)

Kendall, Jordan D.; Melosh, H. J.

2016-08-01

The abundance of moderately siderophile elements (;iron-loving;; e.g. Co, Ni) in the Earth's mantle is 10 to 100 times larger than predicted by chemical equilibrium between silicate melt and iron at low pressure, but it does match expectation for equilibrium at high pressure and temperature. Recent studies of differentiated planetesimal impacts assume that planetesimal cores survive the impact intact as concentrated masses that passively settle from a zero initial velocity and undergo turbulent entrainment in a global magma ocean; under these conditions, cores greater than 10 km in diameter do not fully mix without a sufficiently deep magma ocean. We have performed hydrocode simulations that revise this assumption and yield a clearer picture of the impact process for differentiated planetesimals possessing iron cores with radius = 100 km that impact into magma oceans. The impact process strips away the silicate mantle of the planetesimal and then stretches the iron core, dispersing the liquid iron into a much larger volume of the underlying liquid silicate mantle. Lagrangian tracer particles track the initially intact iron core as the impact stretches and disperses the core. The final displacement distance of initially closest tracer pairs gives a metric of core stretching. The statistics of stretching imply mixing that separates the iron core into sheets, ligaments, and smaller fragments, on a scale of 10 km or less. The impact dispersed core fragments undergo further mixing through turbulent entrainment as the molten iron fragments rain through the magma ocean and settle deeper into the planet. Our results thus support the idea that iron in the cores of even large differentiated planetesimals can chemically equilibrate deep in a terrestrial magma ocean.

The effect of gold kiwifruit consumed with an iron fortified breakfast cereal meal on iron status in women with low iron stores: A 16 week randomised controlled intervention study

PubMed Central

2010-01-01

Background Dietary treatment is often recommended as the first line of treatment for women with mild iron deficiency. Although it is well established that ascorbic acid enhances iron absorption, it is less clear whether the consumption of ascorbic acid rich foods (such as kiwifruit) with meals fortified with iron improves iron status. The aim of this study is to investigate whether the consumption of ZESPRI® GOLD kiwifruit (a fruit high in ascorbic acid and carotenoids) with an iron fortified breakfast cereal meal increases iron status in women with low iron stores. Methods/Design Eighty nine healthy women aged 18-44 years with low iron stores (serum ferritin (SF) ≤ 25 μg/L, haemoglobin (Hb) ≥ 115 g/L) living in Auckland, New Zealand were randomised to receive an iron fortified breakfast cereal (16 mg iron per serve) and either two ZESPRI® GOLD kiwifruit or a banana (low ascorbic acid and carotenoid content) to eat at breakfast time every day for 16 weeks. Iron status (SF, Hb, C-reactive protein (CRP) and soluble transferrin receptor (sTfR)), ascorbic acid and carotenoid status were measured at baseline and after 16 weeks. Anthropometric measures, dietary intake, physical activity and blood loss were measured before and after the 16 week intervention. Discussion This randomised controlled intervention study will be the first study to investigate the effect of a dietary based intervention of an iron fortified breakfast cereal meal combined with an ascorbic acid and carotenoid rich fruit on improving iron status in women with low iron stores. Trial registration ACTRN12608000360314 PMID:20102633

Candida albicans Hap43 Is a Repressor Induced under Low-Iron Conditions and Is Essential for Iron-Responsive Transcriptional Regulation and Virulence ▿

PubMed Central

Hsu, Po-Chen; Yang, Cheng-Yao; Lan, Chung-Yu

2011-01-01

Candida albicans is an opportunistic fungal pathogen that exists as normal flora in healthy human bodies but causes life-threatening infections in immunocompromised patients. In addition to innate and adaptive immunities, hosts also resist microbial infections by developing a mechanism of “natural resistance” that maintains a low level of free iron to restrict the growth of invading pathogens. C. albicans must overcome this iron-deprived environment to cause infections. There are three types of iron-responsive transcriptional regulators in fungi; Aft1/Aft2 activators in yeast, GATA-type repressors in many fungi, and HapX/Php4 in Schizosaccharomyces pombe and Aspergillus species. In this study, we characterized the iron-responsive regulator Hap43, which is the C. albicans homolog of HapX/Php4 and is repressed by the GATA-type repressor Sfu1 under iron-sufficient conditions. We provide evidence that Hap43 is essential for the growth of C. albicans under low-iron conditions and for C. albicans virulence in a mouse model of infection. Hap43 was not required for iron acquisition under low-iron conditions. Instead, it was responsible for repression of genes that encode iron-dependent proteins involved in mitochondrial respiration and iron-sulfur cluster assembly. We also demonstrated that Hap43 executes its function by becoming a transcriptional repressor and accumulating in the nucleus in response to iron deprivation. Finally, we found a connection between Hap43 and the global corepressor Tup1 in low-iron-induced flavinogenesis. Taken together, our data suggest a complex interplay among Hap43, Sfu1, and Tup1 to coordinately regulate iron acquisition, iron utilization, and other iron-responsive metabolic activities. PMID:21131439

Genome mining and functional genomics for siderophore production in Aspergillus niger.

PubMed

Franken, Angelique C W; Lechner, Beatrix E; Werner, Ernst R; Haas, Hubertus; Lokman, B Christien; Ram, Arthur F J; van den Hondel, Cees A M J J; de Weert, Sandra; Punt, Peter J

2014-11-01

Iron is an essential metal for many organisms, but the biologically relevant form of iron is scarce because of rapid oxidation resulting in low solubility. Simultaneously, excessive accumulation of iron is toxic. Consequently, iron uptake is a highly controlled process. In most fungal species, siderophores play a central role in iron handling. Siderophores are small iron-specific chelators that can be secreted to scavenge environmental iron or bind intracellular iron with high affinity. A second high-affinity iron uptake mechanism is reductive iron assimilation (RIA). As shown in Aspergillus fumigatus and Aspergillus nidulans, synthesis of siderophores in Aspergilli is predominantly under control of the transcription factors SreA and HapX, which are connected by a negative transcriptional feedback loop. Abolishing this fine-tuned regulation corroborates iron homeostasis, including heme biosynthesis, which could be biotechnologically of interest, e.g. the heterologous production of heme-dependent peroxidases. Aspergillus niger genome inspection identified orthologues of several genes relevant for RIA and siderophore metabolism, as well as sreA and hapX. Interestingly, genes related to synthesis of the common fungal extracellular siderophore triacetylfusarinine C were absent. Reverse-phase high-performance liquid chromatography (HPLC) confirmed the absence of triacetylfusarinine C, and demonstrated that the major secreted siderophores of A. niger are coprogen B and ferrichrome, which is also the dominant intracellular siderophore. In A. niger wild type grown under iron-replete conditions, the expression of genes involved in coprogen biosynthesis and RIA was low in the exponential growth phase but significantly induced during ascospore germination. Deletion of sreA in A. niger resulted in elevated iron uptake and increased cellular ferrichrome accumulation. Increased sensitivity toward phleomycin and high iron concentration reflected the toxic effects of excessive iron uptake. Moreover, SreA-deficiency resulted in increased accumulation of heme intermediates, but no significant increase in heme content. Together with the upregulation of several heme biosynthesis genes, these results reveal a complex heme regulatory mechanism. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

H. J. Heinz Company: "To Do a Common Thing Uncommonly Well." Fourth Grade Social Studies Unit.

ERIC Educational Resources Information Center

Eckert, Jennifer

This integrated unit on the H. J. Heinz Company is intended for fourth grade and provides a broad understanding of history, social science, geography, science, mathematics, literature and economics. Students will discover that many other industries, besides iron and steel, were prospering in the mid-1800s. The table of contents lists: (1)…

A Consensus for Classification and Pathologic Reporting of Pseudomyxoma Peritonei and Associated Appendiceal Neoplasia: The Results of the Peritoneal Surface Oncology Group International (PSOGI) Modified Delphi Process.

PubMed

Carr, Norman J; Cecil, Thomas D; Mohamed, Faheez; Sobin, Leslie H; Sugarbaker, Paul H; González-Moreno, Santiago; Taflampas, Panos; Chapman, Sara; Moran, Brendan J

2016-01-01

Pseudomyxoma peritonei (PMP) is a complex disease with unique biological behavior that usually arises from appendiceal mucinous neoplasia. The classification of PMP and its primary appendiceal neoplasia is contentious, and an international modified Delphi consensus process was instigated to address terminology and definitions. A classification of mucinous appendiceal neoplasia was developed, and it was agreed that "mucinous adenocarcinoma" should be reserved for lesions with infiltrative invasion. The term "low-grade appendiceal mucinous neoplasm" was supported and it was agreed that "cystadenoma" should no longer be recommended. A new term of "high-grade appendiceal mucinous neoplasm" was proposed for lesions without infiltrative invasion but with high-grade cytologic atypia. Serrated polyp with or without dysplasia was preferred for tumors with serrated features confined to the mucosa with an intact muscularis mucosae. Consensus was achieved on the pathologic classification of PMP, defined as the intraperitoneal accumulation of mucus due to mucinous neoplasia characterized by the redistribution phenomenon. Three categories of PMP were agreed-low grade, high grade, and high grade with signet ring cells. Acellular mucin should be classified separately. It was agreed that low-grade and high-grade mucinous carcinoma peritonei should be considered synonymous with disseminated peritoneal adenomucinosis and peritoneal mucinous carcinomatosis, respectively. A checklist for the pathologic reporting of PMP and appendiceal mucinous neoplasms was also developed. By adopting the classifications and definitions that were agreed, different centers will be able to use uniform terminology that will allow meaningful comparison of their results.

Magnetic design and field optimization of a superferric dipole for the RISP fragment separator

NASA Astrophysics Data System (ADS)

Zaghloul, A.; Kim, J. Y.; Kim, D. G.; Jo, H. C.; Kim, M. J.

2015-10-01

The in-flight fragment separator of the Rare Isotope Science Project requires eight dipole magnets to produce a gap field of 1.7 T in a deflection sector of 30 degree with a 6-m central radius. If the beam-optics requirements are to be met, an integral field homogeneity of a few units (1 unit = 10-4) must be achieved. A superferric dipole magnet has been designed by using the Low-Temperature Superconducting wire NbTi and soft iron of grade SAE1010. The 3D magnetic design and field optimization have been performed using the Opera code. The length and the width of the air slots in the poles have been determined in an optimization process that considered not only the uniformity of the field in the straight section but also the field errors in the end regions. The field uniformity has also been studied for a range of operation of the dipole magnet from 0.4 T to 1.7 T. The magnetic design and field uniformity are discussed.

Is hepcidin a new cardiovascular risk marker in polycystic ovary syndrome?

PubMed

Gözdemir, Elif; Kaygusuz, Ikbal; Kafalı, Hasan

2013-01-01

Polycystic ovary syndrome (PCOS) is associated with reproductive and metabolic abnormalities and carries a number of cardiovascular risk factors. Low-grade chronic inflammation has been thought to play a role in the pathogenesis of atherosclerosis and PCOS patients have an increased rate of subclinical inflammation. In the present study, considering the major role that hepcidin plays in the regulation of iron metabolism and as an inflammatory marker, we investigated hepcidin in PCOS patients and its role in predicting cardiovascular disease (CVD) development. Forty patients with PCOS and 40 age- and body mass index-matched healthy controls were included in the study. Iron metabolites, insulin resistance (IR), inflammatory markers and hepcidin levels were analyzed. IR parameters, inflammatory markers, iron parameters and hepcidin levels were similar between the PCOS and control groups. While the inflammatory markers were significantly high in the overweight and obese PCOS subgroup, the hepcidin levels were also high but this elevation was not statistically significant. Obesity is the principle mechanism of chronic inflammation and IR in PCOS patients. C-reactive protein and interleukin-6 should be used to predict and follow the risk of CVD development in PCOS cases. Hepcidin may be used as an additional marker in the follow-up of PCOS patients in the future. Copyright © 2013 S. Karger AG, Basel.

Mercury mass flow in iron and steel production process and its implications for mercury emission control.

PubMed

Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Gao, Wei; Wu, Qingru; Hao, Jiming

2016-05-01

The iron and steel production process is one of the predominant anthropogenic sources of atmospheric mercury emissions worldwide. In this study, field tests were conducted to study mercury emission characteristics and mass flows at two iron and steel plants in China. It was found that low-sulfur flue gas from sintering machines could contribute up to 41% of the total atmospheric mercury emissions, and desulfurization devices could remarkably help reduce the emissions. Coal gas burning accounted for 17%-49% of the total mercury emissions, and therefore the mercury control of coal gas burning, specifically for the power plant burning coal gas to generate electricity, was significantly important. The emissions from limestone and dolomite production and electric furnaces can contribute 29.3% and 4.2% of the total mercury emissions from iron and steel production. More attention should be paid to mercury emissions from these two processes. Blast furnace dust accounted for 27%-36% of the total mercury output for the whole iron and steel production process. The recycling of blast furnace dust could greatly increase the atmospheric mercury emissions and should not be conducted. The mercury emission factors for the coke oven, sintering machine and blast furnace were 0.039-0.047gHg/ton steel, and for the electric furnace it was 0.021gHg/ton steel. The predominant emission species was oxidized mercury, accounting for 59%-73% of total mercury emissions to air. Copyright © 2016. Published by Elsevier B.V.

An unusual case of iron deficiency anemia is associated with extremely low level of transferrin receptor.

PubMed

Hao, Shuangying; Li, Huihui; Sun, Xiaoyan; Li, Juan; Li, Kuanyu

2015-01-01

A case study of a female patient, diagnosed with iron deficiency anemia, was unresponsive to oral iron treatment and only partially responsive to parenteral iron therapy, a clinical profile resembling the iron-refractory iron deficiency anemia (IRIDA) disorder. However, the patient failed to exhibit microcytic phenotype, one of the IRIDA hallmarks. Biochemical assays revealed that serum iron, hepcidin, interluekin 6, and transferrin saturation were within the normal range of references or were comparable to her non-anemic offspring. Iron contents in serum and red blood cells and hemoglobin levels were measured, which confirmed the partial improvement of anemia after parenteral iron therapy. Strikingly, serum transferrin receptor in patient was almost undetectable, reflecting the very low activity of bone-marrow erythropoiesis. Our data demonstrate that this is not a case of systemic iron deficiency, but rather cellular iron deficit due to the low level of transferrin receptor, particularly in erythroid tissue.

Simultaneous Purification and Perforation of Low-Grade Si Sources for Lithium-Ion Battery Anode.

PubMed

Jin, Yan; Zhang, Su; Zhu, Bin; Tan, Yingling; Hu, Xiaozhen; Zong, Linqi; Zhu, Jia

2015-11-11

Silicon is regarded as one of the most promising candidates for lithium-ion battery anodes because of its abundance and high theoretical capacity. Various silicon nanostructures have been heavily investigated to improve electrochemical performance by addressing issues related to structure fracture and unstable solid-electrolyte interphase (SEI). However, to further enable widespread applications, scalable and cost-effective processes need to be developed to produce these nanostructures at large quantity with finely controlled structures and morphologies. In this study, we develop a scalable and low cost process to produce porous silicon directly from low grade silicon through ball-milling and modified metal-assisted chemical etching. The morphology of porous silicon can be drastically changed from porous-network to nanowire-array by adjusting the component in reaction solutions. Meanwhile, this perforation process can also effectively remove the impurities and, therefore, increase Si purity (up to 99.4%) significantly from low-grade and low-cost ferrosilicon (purity of 83.4%) sources. The electrochemical examinations indicate that these porous silicon structures with carbon treatment can deliver a stable capacity of 1287 mAh g(-1) over 100 cycles at a current density of 2 A g(-1). This type of purified porous silicon with finely controlled morphology, produced by a scalable and cost-effective fabrication process, can also serve as promising candidates for many other energy applications, such as thermoelectrics and solar energy conversion devices.

Localized sulfate-reducing zones in a coastal plain aquifer

USGS Publications Warehouse

Brown, C.J.; Coates, J.D.; Schoonen, M.A.A.

1999-01-01

High concentrations of dissolved iron in ground water of coastal plain or alluvial aquifers contribute to the biofouling of public supply wells for which treatment and remediation is costly. Many of these aquifers, however, contain zones in which microbial sulfate reduction and the associated precipitation of iron-sulfide minerals decreases iron mobility. The principal water-bearing aquifer (Magothy Aquifer of Cretaceous age) in Suffolk County, New York, contains localized sulfate-reducing zones in and near lignite deposits, which generally are associated with clay lenses. Microbial analyses of core samples amended with [14C]-acetate indicate that microbial sulfate reduction is the predominant terminal-electron-accepting process (TEAP) in poorly permeable, lignite-rich sediments at shallow depths and near the ground water divide. The sulfate-reducing zones are characterized by abundant lignite and iron-sulfide minerals, low concentrations of Fe(III) oxyhydroxides, and by proximity to clay lenses that contain pore water with relatively high concentrations of sulfate and dissolved organic carbon. The low permeability of these zones and, hence, the long residence time of ground water within them, permit the preservation and (or) allow the formation of iron-sulfide minerals, including pyrite and marcasite. Both sulfate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) are present beneath and beyond the shallow sulfate-reducing zones. A unique Fe(III)-reducing organism, MD-612, was found in core sediments from a depth of 187 m near the southern shore of Long Island. The distribution of poorly permeable, lignite-rich, sulfate-reducing zones with decreased iron concentration is varied within the principal aquifer and accounts for the observed distribution of dissolved sulfate, iron, and iron sulfides in the aquifer. Locating such zones for the placement of production wells would be difficult, however, because these zones are of limited aerial extent.

Inorganic nanofibers with tailored placement of nanocatalysts for hydrogen production via alkaline hydrolysis of glucose.

PubMed

Hansen, Nathaniel S; Ferguson, Thomas E; Panels, Jeanne E; Park, Ah-Hyung Alissa; Joo, Yong Lak

2011-08-12

Monoaxial silica nanofibers containing iron species as well as coaxial nanofibers with a pure silica core and a silica shell containing high concentrations of iron nanocrystals were fabricated via electrospinning precursor solutions, followed by thermal treatment. Tetraethyl-orthosilicate (TEOS) and iron nitrate (Fe(NO(3))(3)) were used as the precursors for the silica and iron phases, respectively. Thermal treatments of as-spun precursor fibers were applied to generate nanocrystals of iron with various oxidation states (pure iron and hematite). Scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to probe the fiber morphology and crystal structures. The results indicated that the size, phase, and placement of iron nanocrystals can be tuned by varying the precursor concentration, thermal treatment conditions, and processing scheme. The resulting nanofiber/metal systems obtained via both monoaxial and coaxial electrospinning were applied as catalysts to the alkaline hydrolysis of glucose for the production of fuel gas. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and bulk weight change in a furnace with residual gas analysis (RGA) were used to evaluate the performance of the catalysts for various ratios of both Fe to Si, and catalyst to glucose, and the oxidation state of the iron nanocrystals. The product gas is composed of mostly H(2) (>96 mol%) and CH(4) with very low concentrations of CO(2) and CO. Due to the clear separation of reaction temperature for H(2) and CH(4) production, pure hydrogen can be obtained at low reaction temperatures. Our coaxial approach demonstrates that placing the iron species selectively near the fiber surface can lead to two to three fold reduction in catalytic consumption compared to the monoaxial fibers with uniform distribution of catalysts.

Physical activity of children: a global matrix of grades comparing 15 countries.

PubMed

Tremblay, Mark S; Gray, Casey E; Akinroye, Kingsley; Harrington, Dierdre M; Katzmarzyk, Peter T; Lambert, Estelle V; Liukkonen, Jarmo; Maddison, Ralph; Ocansey, Reginald T; Onywera, Vincent O; Prista, Antonio; Reilly, John J; Rodríguez Martínez, María Pilar; Sarmiento Duenas, Olga L; Standage, Martyn; Tomkinson, Grant

2014-05-01

The Active Healthy Kids Canada (AHKC) Report Card on Physical Activity for Children and Youth has been effective in powering the movement to get kids moving by influencing priorities, policies, and practice in Canada. The AHKC Report Card process was replicated in 14 additional countries from 5 continents using 9 common indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behavior, Family and Peers, School, Community and Built Environment, and Government Strategies and Investments), a harmonized process and a standardized grading framework. The 15 Report Cards were presented at the Global Summit on the Physical Activity of Children in Toronto on May 20, 2014. The consolidated findings are summarized here in the form of a global matrix of grades. There is a large spread in grades across countries for most indicators. Countries that lead in certain indicators lag in others. Overall, the grades for indicators of physical activity (PA) around the world are low/poor. Many countries have insufficient information to assign a grade, particularly for the Active Play and Family and Peers indicators. Grades for Sedentary Behaviors are, in general, better in low income countries. The Community and Built Environment indicator received high grades in high income countries and notably lower grades in low income countries. There was a pattern of higher PA and lower sedentary behavior in countries reporting poorer infrastructure, and lower PA and higher sedentary behavior in countries reporting better infrastructure, which presents an interesting paradox. Many surveillance and research gaps and weaknesses were apparent. International cooperation and cross-fertilization is encouraged to tackle existing challenges, understand underlying mechanisms, derive innovative solutions, and overcome the expanding childhood inactivity crisis.

Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

PubMed

Herting, G; Wallinder, I Odnevall; Leygraf, C

2008-09-01

Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

An Analysis of the Published Mineral Resource Estimates of the Haji-Gak Iron Deposit, Afghanistan

USGS Publications Warehouse

Sutphin, D.M.; Renaud, K.M.; Drew, L.J.

2011-01-01

The Haji-Gak iron deposit of eastern Bamyan Province, eastern Afghanistan, was studied extensively and resource calculations were made in the 1960s by Afghan and Russian geologists. Recalculation of the resource estimates verifies the original estimates for categories A (in-place resources known in detail), B (in-place resources known in moderate detail), and C 1 (in-place resources estimated on sparse data), totaling 110. 8 Mt, or about 6% of the resources as being supportable for the methods used in the 1960s. C 2 (based on a loose exploration grid with little data) resources are based on one ore grade from one drill hole, and P 2 (prognosis) resources are based on field observations, field measurements, and an ore grade derived from averaging grades from three better sampled ore bodies. C 2 and P 2 resources are 1,659. 1 Mt or about 94% of the total resources in the deposit. The vast P 2 resources have not been drilled or sampled to confirm their extent or quality. The purpose of this article is to independently evaluate the resources of the Haji-Gak iron deposit by using the available geologic and mineral resource information including geologic maps and cross sections, sampling data, and the analog-estimating techniques of the 1960s to determine the size and tenor of the deposit. ?? 2011 International Association for Mathematical Geology (outside the USA).

In Rwandese Women with Low Iron Status, Iron Absorption from Low-Phytic Acid Beans and Biofortified Beans Is Comparable, but Low-Phytic Acid Beans Cause Adverse Gastrointestinal Symptoms.

PubMed

Petry, Nicolai; Rohner, Fabian; Gahutu, Jean Bosco; Campion, Bruno; Boy, Erick; Tugirimana, Pierrot L; Zimmerman, Michael Bruce; Zwahlen, Christian; Wirth, James P; Moretti, Diego

2016-05-01

Phytic acid (PA) is a major inhibitor of iron bioavailability from beans, and high PA concentrations might limit the positive effect of biofortified beans (BBs) on iron status. Low-phytic acid (lpa) bean varieties could increase iron bioavailability. We set out to test whether lpa beans provide more bioavailable iron than a BB variety when served as part of a composite meal in a bean-consuming population with low iron status. Dietary iron absorption from lpa, iron-biofortified, and control beans (CBs) (regular iron and PA concentrations) was compared in 25 nonpregnant young women with low iron status with the use of a multiple-meal crossover design. Iron absorption was measured with stable iron isotopes. PA concentration in lpa beans was ∼10% of BBs and CBs, and iron concentration in BBs was ∼2- and 1.5-fold compared with CBs and lpa beans, respectively. Fractional iron absorption from lpa beans [8.6% (95% CI: 4.8%, 15.5%)], BBs [7.3% (95% CI: 4.0%, 13.4%)], and CBs [8.0% (95% CI: 4.4%, 14.6%)] did not significantly differ. The total amount of iron absorbed from lpa beans and BBs was 421 μg (95% CI: 234, 756 μg) and 431 μg (95% CI: 237, 786 μg), respectively, and did not significantly differ, but was >50% higher (P < 0.005) than from CBs (278 μg; 95% CI: 150, 499 μg). In our trial, the lpa beans were hard to cook, and their consumption caused transient adverse digestive side effects in ∼95% of participants. Gel electrophoresis analysis showed phytohemagglutinin L (PHA-L) residues in cooked lpa beans. BBs and lpa beans provided more bioavailable iron than control beans and could reduce dietary iron deficiency. Digestive side effects of lpa beans were likely caused by PHA-L, but it is unclear to what extent the associated digestive problems reduced iron bioavailability. This trial was registered at clinicaltrials.gov as NCT02215278. © 2016 American Society for Nutrition.

Magnetite/Fe-Al-montmorillonite as a Fenton catalyst with efficient degradation of phenol.

PubMed

Wei, Xipeng; Wu, Honghai; Sun, Feng

2017-10-15

A Fe-Al-MPM material assembled from nanosized magnetite and Fe-Al-pillared montmorillonite (Fe-Al-Mt) was characterized by XRD, XPS, BET, SEM and TEM. Fe-Al-Mt was proven to be capable of facilitating the dispersion of magnetite nanoparticles and inhibiting their aggregation. The coupling of Fe-Al-Mt with magnetite in Fe-Al-MPM improved its Fenton catalytic activity. Complete conversion of phenol within 80min with a high TOC removal rate (>78%) was achieved using Fe-Al-MPM as a heterogeneous Fenton catalyst under optimized conditions. The Fenton process first underwent a slow induction reaction, followed by the rapid oxidative decomposition of phenol. The existence of the induction reaction period was attributed to the need for activation of the iron species on the catalyst surfaces, and the duration depended on the solution temperature, pH and catalyst's nature. More importantly, Fe-Al-MPM showed high stability, with a low iron-release even after it was recycled 5 times. The minimal iron-leaching from Fe-Al-MPM was ascribed to the competitive adsorption of the incorporated aluminum and all the iron species for the residual (low ecotoxicity) organic ligands. These organic acids were among the main products that remained at the end of the Fenton process. Also important was the ease of separation of Fe-Al-MPM under a magnetic field. Copyright © 2017 Elsevier Inc. All rights reserved.

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park

PubMed Central

Kozubal, Mark A; Romine, Margaret; Jennings, Ryan deM; Jay, Zack J; Tringe, Susannah G; Rusch, Doug B; Beam, Jacob P; McCue, Lee Ann; Inskeep, William P

2013-01-01

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron-oxide mats in YNP. Detailed analysis of conserved ribosomal and informational processing genes indicates that the replicate assemblies represent a new candidate phylum within the domain Archaea referred to here as ‘Geoarchaeota' or ‘novel archaeal group 1 (NAG1)'. The NAG1 organisms contain pathways necessary for the catabolism of peptides and complex carbohydrates as well as a bacterial-like Form I carbon monoxide dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in the metabolism of oxygen including a Type A heme copper oxidase, a bd-type terminal oxidase and a putative oxygen-sensing protoglobin. NAG1 has a variety of unique bacterial-like cofactor biosynthesis and transport genes and a Type3-like CRISPR system. Discovery of NAG1 is critical to our understanding of microbial community structure and function in extant thermophilic iron-oxide mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogs active in YNP today. PMID:23151644

Iron deficiency defined as depleted iron stores accompanied by unmet cellular iron requirements identifies patients at the highest risk of death after an episode of acute heart failure.

PubMed

Jankowska, Ewa A; Kasztura, Monika; Sokolski, Mateusz; Bronisz, Marek; Nawrocka, Sylwia; Oleśkowska-Florek, Weronika; Zymliński, Robert; Biegus, Jan; Siwołowski, Paweł; Banasiak, Waldemar; Anker, Stefan D; Filippatos, Gerasimos; Cleland, John G F; Ponikowski, Piotr

2014-09-21

Acute heart failure (AHF) critically deranges haemodynamic and metabolic homoeostasis. Iron is a key micronutrient for homoeostasis maintenance. We hypothesized that iron deficiency (ID) defined as depleted iron stores accompanied by unmet cellular iron requirements would in this setting predict the poor outcome. Among 165 AHF patients (age 65 ± 12 years, 81% men, 31% de novo HF), for ID diagnosis we prospectively applied: low serum hepcidin reflecting depleted iron stores (<14.5 ng/mL, the 5th percentile in healthy peers), and high-serum soluble transferrin receptor (sTfR) reflecting unmet cellular iron requirements (≥1.59 mg/L, the 95th percentile in healthy peers). Concomitance of low hepcidin and high sTfR (the most profound ID) was found in 37%, isolated either high sTfR or low hepcidin was found in 29 and 9% of patients, and 25% of subjects demonstrated preserved iron status. Patients with low hepcidin and high sTfR had peripheral oedema, high NT-proBNP, high uric acid, low haemoglobin (P < 0.05), and 5% in-hospital mortality (0% in remaining patients). During the 12-month follow-up, 33 (20%) patients died. Those with low hepcidin and high sTfR had the highest 12-month mortality [(41% (95% CI: 29-53%)] when compared with those with isolated high sTfR [15% (5-25%)], isolated low hepcidin [7% (0-19%)] and preserved iron status (0%) (P < 0.001). Analogous mortality patterns were seen separately in anaemics and non-anaemics. Iron deficiency defined as depleted body iron stores and unmet cellular iron requirements is common in AHF, and identifies those with the poor outcome. Its correction may be an attractive therapeutic approach. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Development of processes for the production of solar grade silicon from halides and alkali metals

NASA Technical Reports Server (NTRS)

Dickson, C. R.; Gould, R. K.

1980-01-01

High temperature reactions of silicon halides with alkali metals for the production of solar grade silicon in volume at low cost were studied. Experiments were performed to evaluate product separation and collection processes, measure heat release parameters for scaling purposes, determine the effects of reactants and/or products on materials of reactor construction, and make preliminary engineering and economic analyses of a scaled-up process.

Sequential induction of Fur-regulated genes in response to iron limitation in Bacillus subtilis.

PubMed

Pi, Hualiang; Helmann, John D

2017-11-28

Bacterial cells modulate transcription in response to changes in iron availability. The ferric uptake regulator (Fur) senses intracellular iron availability and plays a central role in maintaining iron homeostasis in Bacillus subtilis Here we utilized FrvA, a high-affinity Fe 2+ efflux transporter from Listeria monocytogenes , as an inducible genetic tool to deplete intracellular iron. We then characterized the responses of the Fur, FsrA, and PerR regulons as cells transition from iron sufficiency to deficiency. Our results indicate that the Fur regulon is derepressed in three distinct waves. First, uptake systems for elemental iron ( efeUOB ), ferric citrate ( fecCDEF ), and petrobactin ( fpbNOPQ ) are induced to prevent iron deficiency. Second, B. subtilis synthesizes its own siderophore bacillibactin ( dhbACEBF ) and turns on bacillibactin ( feuABC ) and hydroxamate siderophore ( fhuBCGD ) uptake systems to scavenge iron from the environment and flavodoxins ( ykuNOP ) to replace ferredoxins. Third, as iron levels decline further, an "iron-sparing" response ( fsrA , fbpAB , and fbpC ) is induced to block the translation of abundant iron-utilizing proteins and thereby permit the most essential iron-dependent enzymes access to the limited iron pools. ChIP experiments demonstrate that in vivo occupancy of Fur correlates with derepression of each operon, and the graded response observed here results, at least in part, from higher-affinity binding of Fur to the "late"-induced genes.

Magnetophoresis of iron oxide nanoparticles at low field gradient: the role of shape anisotropy.

PubMed

Lim, Jitkang; Yeap, Swee Pin; Leow, Chee Hoe; Toh, Pey Yi; Low, Siew Chun

2014-05-01

Magnetophoresis of iron oxide magnetic nanoparticle (IOMNP) under low magnetic field gradient (<100 T/m) is significantly enhanced by particle shape anisotropy. This unique feature of magnetophoresis is influenced by the particle concentration and applied magnetic field gradient. By comparing the nanosphere and nanorod magnetophoresis at different concentration, we revealed the ability for these two species of particles to achieve the same separation rate by adjusting the field gradient. Under cooperative magnetophoresis, the nanorods would first go through self- and magnetic field induced aggregation followed by the alignment of the particle clusters formed with magnetic field. Time scale associated to these two processes is investigated to understand the kinetic behavior of nanorod separation under low field gradient. Surface functionalization of nanoparticles can be employed as an effective strategy to vary the temporal evolution of these two aggregation processes which subsequently influence the magnetophoretic separation time and rate. Copyright © 2014 Elsevier Inc. All rights reserved.

[Performance Study of Bromochloracetonitrile Degradation in Drinking Water by Fe/Cu Catalytic Reduction].

PubMed

Ding, Chun-sheng; Ma, Hai-long; Fu, Yang-ping; Zhao, Shi-du; Li, Dong-bing

2015-06-01

The paper used the method of iron copper catalyst reduction to degrade low concentrations of bromochloracetonitrile (BCAN) to lighten the damage to human being, which is a kind of disinfection by-products (DBPs) produced during the chlorination process of drinking water. The removal efficiency of BCAN and its influencing factors were investigated. The mechanism of degradation and kinetics were also explored. The results indicated that iron copper had a greater degradation ability towards BCAN, and the degradation rate of iron copper (mass ratio of 10:1) was 1.5 times that of the zero-valent iron. The removal of BCAN increased obviously with the increase of Fe/Cu dosage. When the initial concentration was set at 20 microg x L(-1), after a reaction time of 150 min, removal of BCAN was improved from 51.1% to 89.5% with the increase of iron copper (mass ratio of 10:1) dosage from 5 g x L(-1) to 10 g x L(-1). The temperature also had great impact on BCAN removal and the removal increased with the increase of temperature. However, BCAN removal did not change a lot with the variation of the initial concentration of BCAN when it was at a low level. The BCAN degradation by iron copper catalytic-reduction followed the first-order kinetics model.

Soybean hulls as an iron source for bread enrichment

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

Johnson, C.D.; Berry, M.F.; Weaver, C.M.

Soybean hulls, a concentrated source of iron, may have potential as a source of iron fortification in baked products. Retention of /sup 59/Fe in rats from white bread containing intrinsically labeled soybean hulls did not differ significantly (p<0.05) from extrinsically labeled white bread fortified with bakery grade ferrous sulfate (70.4 and 63.1%, respectively). Physical and sensory evaluations of bread containing up to 5% soybean hulls did not differ from white bread in loaf volume, cross-sectional area, tenderness or overall acceptance. These results suggest that soybean hulls are a good source of available iron and may be added to bakery productsmore » without deleterious effects in baking performance and sensory acceptability.« less

Low cost solar array project: Experimental process system development unit for producing semiconductor-grade silicon using silane-to-silicon process

NASA Technical Reports Server (NTRS)

1980-01-01

The design, fabrication, and installation of an experimental process system development unit (EPSDU) were analyzed. Supporting research and development were performed to provide an information data base usable for the EPSDU and for technological design and economical analysis for potential scale-up of the process. Iterative economic analyses were conducted for the estimated product cost for the production of semiconductor grade silicon in a facility capable of producing 1000-MT/Yr.

Hidden values in bauxite residue (red mud): recovery of metals.

PubMed

Liu, Yanju; Naidu, Ravi

2014-12-01

Bauxite residue (red mud) is a hazardous waste generated from alumina refining industries. Unless managed properly, red mud poses significant risks to the local environment due to its extreme alkalinity and its potential impacts on surface and ground water quality. The ever-increasing generation of red mud poses significant challenges to the aluminium industries from management perspectives given the low proportion that are currently being utilized beneficially. Red mud, in most cases, contains elevated concentrations of iron in addition to aluminium, titanium, sodium and valuable rare earth elements. Given the scarcity of iron supply globally, the iron content of red mud has attracted increasing research interest. This paper presents a critical overview of the current techniques employed for iron recovery from red mud. Information on the recovery of other valuable metals is also reviewed to provide an insight into the full potential usage of red mud as an economic resource rather than a waste. Traditional hydrometallurgy and pyrometallurgy are being investigated continuously. However, in this review several new techniques are introduced that consider the process of iron recovery from red mud. An integrated process which can achieve multiple additional values from red mud is much preferred over the single process methods. The information provided here should help to improve the future management and utilization of red mud. Copyright © 2014 Elsevier Ltd. All rights reserved.

Psychological distress, iron deficiency, active disease and female gender are independent risk factors for fatigue in patients with ulcerative colitis

PubMed Central

Jonefjäll, Börje; Simrén, Magnus; Lasson, Anders; Öhman, Lena; Strid, Hans

2017-01-01

Background Patients with ulcerative colitis often report fatigue. Objectives To investigate prevalence of and risk factors for fatigue in patients with ulcerative colitis with active disease and during deep remission. Methods In this cross-sectional study, disease activity was evaluated with endoscopy and calprotectin, and patients were classified as having active disease (n = 133) or being in deep remission (n = 155). Blood samples were analysed to assess anaemia, iron deficiency and systemic immune activity. Patients completed questionnaires to assess fatigue, psychological distress, gastrointestinal symptoms and quality of life. Results The prevalence of high fatigue (general fatigue ≥ 13, Multidimensional Fatigue Inventory) was 40% in the full study population. Among patients with high fatigue, female gender and iron deficiency were more prevalent, and these patients had more severe disease activity and reported higher levels of anxiety, depression and decreased quality of life compared with patients with no/mild fatigue. A logistic regression analysis identified probable psychiatric disorder (odds ratio (OR) (confidence interval) 6.1 (3.1–12.2)), iron deficiency (OR 2.5 (1.2–5.1)), active disease (OR 2.2 (1.2–3.9)) and female gender (OR 2.1 (1.1–3.7)) as independent risk factors for high fatigue. Similar results were found concerning psychological distress, gender and quality of life, but immune markers did not differ in patients in deep remission with high vs. no/mild fatigue. Conclusions Probable psychiatric disorder, iron deficiency, active disease and female gender are independent risk factors for high fatigue in patients with ulcerative colitis. Low-grade immune activity does not seem to be the cause of fatigue among patients in deep remission. PMID:29435325

Parametric Investigation of the Kinetics of Growth of Carbon-Nanotube Arrays on Iron Nanoparticles in the Process of Chemical Vapor Deposition of Hydrocarbons

NASA Astrophysics Data System (ADS)

Futko, S. I.; Shulitski, B. G.; Labunov, V. A.; Ermolaevaa, E. M.

2015-03-01

On the basis of the kinetic model of synthesis of carbon nanotubes on iron nanoparticles in the process of chemical vapor deposition of hydrocarbons, the parametric dependences of characteristics of arrays of vertically oriented nanotubes on the temperature of their synthesis, the concentration of acetylene in a reactor, and the diameter of the catalyst nanoparticles were investigated. It is shown that the maximum on the temperature dependence of the rate of growth of carbon nanotubes, detected in experiments at a temperature of ~700oC is due to the competing processes of increasing the catalytic activity of iron nanoparticles and decreasing the acetylene concentration because of the signifi cant gas-phase decomposition of acetylene in the reactor before it enters the substrate with the catalyst. Our calculations have shown that the indicated maximum arises near the transition point separating the low-temperature region where multiwall nanotubes are predominantly synthesized from the higher-temperature region of generation of single-wall nanotubes in the process of chemical vapor deposition of hydrocarbons.

How low does iron go? Chasing the active species in fe-catalyzed cross-coupling reactions.

PubMed

Bedford, Robin B

2015-05-19

The catalytic cross-coupling reactions of organic halides or related substrates with organometallic nucleophiles form the cornerstone of many carbon-carbon bond-forming processes. While palladium-based catalysts typically mediate such reactions, there are increasing concerns about the long-term sustainability of palladium in synthesis. This is due to the high cost of palladium, coupled with its low natural abundance, environmentally deleterious extraction (∼6 g of metal are produced per ton of ore), toxicity, and competition for its use from the automotive and consumer electronics sectors. Therefore, there is a growing interest in replacing palladium-based catalysts with those incorporating more earth-abundant elements. With its low cost, high natural abundance, and low toxicity, iron makes a particularly appealing alternative, and accordingly, the development of iron-catalyzed cross-coupling is undergoing explosive growth. However, our understanding of the mechanisms that underpin the iron-based catalytic cycles is still very much in its infancy. Mechanistic insight into catalytic reactions is not only academically important but also allows us to maximize the efficiency of processes or even to develop entirely new transformations. Key to the development of robust mechanistic models for cross-coupling is knowing the lowest oxidation state in the cycle. Once this is established, we can explore subsequent redox processes and build the catalytic manifold. Until we know with confidence what the lowest oxidation state is, any cycles proposed are largely just guesswork. To date, Fe(-II), Fe(-I), Fe(0), Fe(I), and Fe(II) have been proposed as contenders for the lowest-oxidation-state species in the cycle in iron-catalyzed cross-coupling; the aim of this Account is to pull together the various pieces of evidence in support, or otherwise, of each of these suggestions in turn. There currently exists no direct evidence that oxidation states below Fe(0) are active in the catalytic cycle. Meanwhile, the reactivity required of the lowest-oxidation-state species has been observed with model compounds in higher oxidation states, implying that there is no need to invoke such low oxidation states. While subzero-valent complexes do indeed act as effective precatalysts, it is important to recognize that this tells us that they are efficiently converted to an active catalyst but says nothing about the oxidation states of the species in the catalytic cycle. Zero-valent heterogeneous iron nanoparticles can be formed under typical catalytic conditions, but there is no evidence to suggest that homogeneous Fe(0) complexes can be produced under comparable conditions. It seems likely that the zero-valent nanoparticles act as a reservoir for soluble higher-oxidation-state species. Fe(II) complexes can certainly be formed under catalytically relevant conditions, and when bulky nucleophilic coupling partners are exploited, potential intermediates can be isolated. However, the bulky reagents act as poor proxies for most nucleophiles used in cross-coupling, as they give Fe(II) organometallic intermediates that are kinetically stabilized with respect to reductive elimination. When more realistic substrates are exploited, reduction or disproportionation to Fe(I) is widely observed, and while it still has not been conclusively proved, this oxidation state currently represents a likely candidate for the lowest one active in many iron-catalyzed cross-coupling processes.

Thermoelectric as recovery and harvesting of waste heat from portable generator

NASA Astrophysics Data System (ADS)

Mustafa, S. N.; Kamarrudin, N. S.; Hashim, M. S. M.; Bakar, S. A.; Razlan, Z. M.; Harun, A.; Ibrahim, I.; Faizi, M. K.; Saad, M. A. M.; Zunaidi, I.; Wan, W. K.; Desa, H.

2017-10-01

Generation of waste heat was ineluctable especially during energy producing process. Waste heat falls into low temperature grade make it complicated to utilize. Thermoelectric generator (TEG) offers opportunity to harvest any temperature grade heat into useful electricity. This project is covered about recovery and utilizing waste heat from portable electric generator by using a TEG which placed at exhaust surface. Temperature difference at both surfaces of TEG was enhanced with supplying cold air from a wind blower. It is found that, even at low air speed, the TEG was successfully produced electricity with aid from DC-DC booster. Results shows possibility to harvest low temperature grade heat and still exist areas for continual improvement.

Preservation of Fe Isotope Proxies in the Rock Record

NASA Astrophysics Data System (ADS)

Johnson, C.; Beard, B.; Valley, J.; Valaas, E.

2005-12-01

Iron isotope variations provide powerful constraints on redox conditions and pathways involved during biogeochemical cycling of Fe in surface and near-surface environments. The relative isotopic homogeneity of igneous rocks and most bulk weathering products contrasts with the significant isotopic variations (4 per mil in 56Fe/54Fe) that accompany oxidation of Fe(II)aq, precipitation of sulfides, and reduction by bacteria. These isotopic variations often reflect intrinsic (equilibrium) Fe isotope fractionations between minerals and aqueous species whose interactions may be directly or indirectly catalyzed by bacteria. In addition, Fe isotope exchange may be limited between reactive Fe pools in low-temperature aqueous-sediment environments, fundamentally reflecting disequilibrium effects. In the absence of significant sulfide, dissimilatory Fe(III) reduction by bacteria produces relatively low 56Fe/54Fe ratios for Fe(II)aq and associated biogenic minerals such as magnetite and siderite. In contrast, Fe(II)aq that exchanges with Fe sulfides (FeS and pyrite) is relatively enriched in 56Fe/54Fe ratios. In modern and ancient environments, anoxic diagenesis tends to produce products that have low 56Fe/54Fe ratios, whereas oxidation of Fe(II)aq from hydrothermal sources tends to produce ferric Fe products that have high 56Fe/54Fe ratios. Redox cycling by bacteria tends to produce reactive ferric Fe reservoirs that have low 56Fe/54Fe ratios. Application of Fe isotopes as a proxy for redox conditions in the ancient rock record depends upon the preservation potential during metamorphism, given the fact that most Archean sedimentary sequences have been subjected to regional greenschist- to granulite-facies metamorphism. The 1.9 Ga banded iron formations (BIFs) of the Lake Superior region that are intruded by large ~1 Ga intrusions (e.g., Duluth gabbro) provide a test of the preservation potential for primary, low-temperature Fe isotope variations in sedimentary rocks. 56Fe/54Fe ratios for re-crystallized magnetite from BIFs of the Biwabik iron formation that have apparent oxygen-isotope (quartz-magnetite) temperatures between 270 and 800 oC span a significant portion of the range measured in lower-grade BIFs from South Africa and Australia. d56Fe values for Biwabik magnetite vary from -0.2 to +0.7 per mil, whereas magnetite from the Dales Gorge member of the Brockman iron formation and the Kuruman iron formation has d56Fe values that lie between -1.2 and +1.3 per mil. Iron isotope fractionations between magnetite and Fe silicates (greenalite, hedenbergite, and fayalite) in the Biwabik iron formation regularly decrease with increasing oxygen-isotope temperatures, approaching the zero fractionation expected at igneous temperatures; apparent magnetite-Fe silicate fractionations range from +0.2 per mil at 650 oC to +0.5 per mil at 300 oC, lying close to those predicted using the revised beta factors of Polyakov et al. (2005, Goldschmidt). During closed-system Fe isotope exchange during metamorphism, the overall range in d56Fe values for magnetite will remain relatively constant, although it may shift to higher d56Fe values relative to primary (low-temperature) magnetite due to the non-zero magnetite-Fe silicate fractionation factor at moderate temperature ranges. If the mineral parageneis is known, and some assumptions regarding primary mineralogy can be made, these small corrections may be made to successfully infer the original Fe isotope compositions of sedimentary minerals and rocks that have been subjected to metamorphism.

Iron bioavailability studies as assessed by intrinsic and extrinsic labeling techniques

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

Johnson, C.D.

Although soybeans are a rich source of iron and incorporation of soy protein into diets is increasing, the presence of phytate or fiber endogenous to the seeds may inhibit total iron absorption from diets including soy protein. Four studies on iron bioavailability as assessed by intrinsic and extrinsic labeling techniques in rats were completed. The effect of previous dietary protein on the absorption of intrinsically /sup 59/Fe labeled defatted soy flour was determined in rats. The results indicated that the type of dietary protein (animal vs. plant) in pre-test diets would have little influence on iron absorption from a singlemore » soy protein test meal. Therefore, adaptation of soy protein does not improve bioavailability of iron. Soybean hulls were investigated as a source of iron fortification in bread. The results indicated that retention of /sup 59/Fe from white bread baked with soy hulls did not differ from white bread fortified with bakery grade ferrous sulfate. The effect of endogenous soybean phytate on iron absorption in rats was measured using seeds of varying phytate content and intrinsically labeled with /sup 59/Fe. Increasing concentration of phytate in whole soybean flour had no significant effect on iron absorption.« less

Involvement of NRAMP1 from Arabidopsis thaliana in iron transport.

PubMed Central

Curie, C; Alonso, J M; Le Jean, M; Ecker, J R; Briat, J F

2000-01-01

Nramp genes code for a widely distributed class of proteins involved in a variety of processes, ranging from the control of susceptibility to bacterial infection in mammalian cells and taste behaviour in Drosophila to manganese uptake in yeast. Some of the NRAMP proteins in mammals and in yeast are capable of transporting metal ions, including iron. In plants, iron transport was shown to require a reduction/Fe(II) transport system. In Arabidopsis thaliana this process involves the IRT1 and Fro2 genes. Here we report the sequence of five NRAMP proteins from A. thaliana. Sequence comparison suggests that there are two classes of NRAMP proteins in plants: A. thaliana (At) NRAMP1 and Oriza sativa (Os) NRAMP1 and 3 (two rice isologues) represent one class, and AtNRAMP2-5 and OsNRAMP2 the other. AtNramp1 and OsNramp1 are able to complement the fet3fet4 yeast mutant defective both in low- and high-affinity iron transports, whereas AtNramp2 and OsNramp2 fail to do so. In addition, AtNramp1 transcript, but not AtNramp2 transcript, accumulates in response to iron deficiency in roots but not in leaves. Finally, overexpression of AtNramp1 in transgenic A. thaliana plants leads to an increase in plant resistance to toxic iron concentration. Taken together, these results demonstrate that AtNramp1 participates in the control of iron homoeostasis in plants. PMID:10769179

A general strategy toward graphitized carbon coating on iron oxides as advanced anodes for lithium-ion batteries.

PubMed

Ding, Chunyan; Zhou, Weiwei; Wang, Bin; Li, Xin; Wang, Dong; Zhang, Yong; Wen, Guangwu

2017-08-25

Integration of carbon materials with benign iron oxides is blazing a trail in constructing high-performance anodes for lithium-ion batteries (LIBs). In this paper, a unique general, simple, and controllable strategy is developed toward in situ uniform coating of iron oxide nanostructures with graphitized carbon (GrC) layers. The basic synthetic procedure only involves a simple dip-coating process for the loading of Ni-containing seeds and a subsequent Ni-catalyzed chemical vapor deposition (CVD) process for the growth of GrC layers. More importantly, the CVD treatment is conducted at a quite low temperature (450 °C) and with extremely facile liquid carbon sources consisting of ethylene glycol (EG) and ethanol (EA). The GrC content of the resulting hybrids can be controllably regulated by altering the amount of carbon sources. The electrochemical results reveal remarkable performance enhancements of iron oxide@GrC hybrids compared with pristine iron oxides in terms of high specific capacity, excellent rate and cycling performance. This can be attributed to the network-like GrC coating, which can improve not only the electronic conductivity but also the structural integrity of iron oxides. Moreover, the lithium storage performance of samples with different GrC contents is measured, manifesting that optimized electrochemical property can be achieved with appropriate carbon content. Additionally, the superiority of GrC coating is demonstrated by the advanced performance of iron oxide@GrC compared with its corresponding counterpart, i.e., iron oxides with amorphous carbon (AmC) coating. All these results indicate the as-proposed protocol of GrC coating may pave the way for iron oxides to be promising anodes for LIBs.

Study and modeling of the ironing process on a multi-layered polymer coated low-carbon steel

NASA Astrophysics Data System (ADS)

Selles Canto, Miguel Angel

The ironing process is the most crucial step in the manufacture of cans. Sheet steel covered by three polymer layers can be used as the starting material, but this coating must neither break nor fail in any manner in order to be considered as a viable and effective alternative to traditional practice. During ironing, the deformations are severe and high pressures exist at the tool-workpiece interface. Thickness reductions inherent in ironing require a large amount of surface generation. Deterioration of the coating in this delicate operation might enable direct contact of the stored food or drink with the metal. As can be appreciated, the key to the use of polymer-coated steel sheets in the manufacture of cans lies in the survival of these layers during the ironing process. Another important issue is the roughness of the newly-generated surface, because it should be possible to decorate the can without any difficulty. Changing the traditional manufacture of metallic containers such as cans and using this new coated material permits great reduction in environmental contaminants produced as a result of avoiding the formation of Volatile Organic Compounds (VOCs) during the manufacture of the polymer layers. This reduction is even greater because of not using additional lubricants due to the self-lubricanting property of the solid polymer coating layers during the drawing process. These objectives, together with the improvement of the mechanical characteristics and the adhesion of the painting or decorative priming, are realized by the use of the proposed material. In the existing bibliography about ironing processes on coated materials, some authors propose the use of the Upper Bound Theorem for modeling the material behavior. The present research shows for the first time the modeling of the ironing process on a three-layer polymer coated material. In addition, it takes into account the cases in which successful ironing is produced and those in which ones the ironing is defective either by shaving or detachment of the upper layer of polymer. Arcelor-Mittal provided two similar materials, both consisting of a steel substrate coated by three polymer layers. They have been tested according to the theory of design of experiments, in order to determine the feasibility of their use in the manufacture of cans. An ironing process simulator has been designed and constructed that works under conditions similar to those in industry. Validation of the theoretically-generated models has been possible thanks to the use of the ironing simulator, providing results that show good agreement between the theoretical and real behaviors. Finally, after obtaining the different results from the theoretical and experimental work, they have been analyzed to determine the feasibility of using these materials for the manufacture of metal containers that need the ironing process. The information obtained from this analysis shows that, under certain conditions, it is perfectly possible to use one of these two materials for the proposed purpose, making the proposed goals possible. The die angle is the most critical variable among all the ones studied, and when it takes values greater than 7°, some of the coating polymer layers are damaged.

Transcriptional response of Atlantic salmon families to Piscirickettsia salmonis infection highlights the relevance of the iron-deprivation defence system.

PubMed

Pulgar, Rodrigo; Hödar, Christian; Travisany, Dante; Zuñiga, Alejandro; Domínguez, Calixto; Maass, Alejandro; González, Mauricio; Cambiazo, Verónica

2015-07-04

Piscirickettsiosis or Salmonid Rickettsial Septicaemia (SRS) is a bacterial disease that has a major economic impact on the Chilean salmon farming industry. Despite the fact that Piscirickettsia salmonis has been recognized as a major fish pathogen for over 20 years, the molecular strategies underlying the fish response to infection and the bacterial mechanisms of pathogenesis are poorly understood. We analysed and compared the head kidney transcriptional response of Atlantic salmon (Salmo salar) families with different levels of susceptibility to P. salmonis infection in order to reveal mechanisms that might confer infection resistance. We ranked forty full-sibling Atlantic salmon families according to accumulated mortality after a challenge with P. salmonis and selected the families with the lowest and highest cumulative mortalities for microarray gene expression analysis. A comparison of the response to P. salmonis infection between low and high susceptibility groups identified biological processes presumably involved in natural resistance to the pathogen. In particular, expression changes of genes linked to cellular iron depletion, as well as low iron content and bacterial load in the head kidney of fish from low susceptibility families, suggest that iron-deprivation is an innate immunity defence mechanism against P. salmonis. To complement these results, we predicted a set of iron acquisition genes from the P. salmonis genome. Identification of putative Fur boxes and expression of the genes under iron-depleted conditions revealed that most of these genes form part of the Fur regulon of P. salmonis. This study revealed, for the first time, differences in the transcriptional response to P. salmonis infection among Atlantic salmon families with varied levels of susceptibility to the infection. These differences correlated with changes in the abundance of transcripts encoding proteins directly and indirectly involved in the immune response; changes that highlighted the role of nutritional immunity through iron deprivation in host defence mechanisms against P. salmonis. Additionally, we found that P. salmonis has several mechanisms for iron acquisition, suggesting that this bacterium can obtain iron from different sources, including ferric iron through capturing endogenous and exogenous siderophores and ferrous iron. Our results contribute to determining the underlying resistance mechanisms of Atlantic salmon to P. salmonis infection and to identifying future treatment strategies.

The Simple View, Instructional Level, and the Plight of Struggling Fifth-/Sixth-Grade Readers

ERIC Educational Resources Information Center

Morris, Darrell; Meyer, Carla; Trathen, Woodrow; McGee, Jennifer; Vines, Nora; Stewart, Trevor; Gill, Tom; Schlagal, Robert

2017-01-01

This study explored print-processing and vocabulary differences among a group of 5th- and 6th-grade students who had scored below the 50th percentile on a standardized reading test. Guided by the simple view of reading, we applied cut scores (low/high) to the students' performance on print-processing and vocabulary tasks. The design allowed for…

Spectral evidence for amorphous silicates in least-processed CO meteorites and their parent bodies

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.; Sunshine, Jessica M.; Howard, Kieren T.; Alexander, Conel M.; McCoy, Timothy J.; Bus, Schelte J.

2018-05-01

Least-processed carbonaceous chondrites (carbonaceous chondrites that have experienced minimal aqueous alteration and thermal metamorphism) are characterized by their predominately amorphous iron-rich silicate interchondrule matrices and chondrule rims. This material is highly susceptible to destruction by the parent body processes of thermal metamorphism or aqueous alteration. The presence of abundant amorphous material in a meteorite indicates that the parent body, or at least a region of the parent body, experienced minimal processing since the time of accretion. The CO chemical group of carbonaceous chondrites has a significant number of these least-processed samples. We present visible/near-infrared and mid-infrared spectra of eight least-processed CO meteorites (petrologic type 3.0-3.1). In the visible/near-infrared, these COs are characterized by a broad weak feature that was first observed by Cloutis et al. (2012) to be at 1.3-μm and attributed to iron-rich amorphous silicate matrix materials. This feature is observed to be centered at 1.4-μm for terrestrially unweathered, least-processed CO meteorites. At mid-infrared wavelengths, a 21-μm feature, consistent with Si-O vibrations of amorphous materials and glasses, is also present. The spectral features of iron-rich amorphous silicate matrix are absent in both the near- and mid-infrared spectra of higher metamorphic grade COs because this material has recrystallized as crystalline olivine. Furthermore, spectra of least-processed primitive meteorites from other chemical groups (CRs, MET 00426 and QUE 99177, and C2-ungrouped Acfer 094), also exhibit a 21-μm feature. Thus, we conclude that the 1.4- and 21-μm features are characteristic of primitive least-processed meteorites from all chemical groups of carbonaceous chondrites. Finally, we present an IRTF + SPeX observation of asteroid (93) Minerva that has spectral similarities in the visible/near-infrared to the least-processed CO carbonaceous chondrites. While Minerva is not the only CO-like asteroid (e.g., Burbine et al., 2001), Minerva is likely the least-processed CO-like asteroid observed to date.

Emulsified Zero-Valent Nano-Scale Iron Treatment of Chlorinated Solvent DNAPL Source Areas

DTIC Science & Technology

2010-04-01

The EZVI is composed of food-grade surfactant, biodegradable oil , water, and ZVI particles (either nano- or micro-scale iron), which form...emulsion particles (Figure 2-1). Each emulsion particle or droplet contains ZVI particles in water surrounded by an oil -liquid membrane. Since the...exterior oil membrane of the emulsion droplet has hydrophobic properties similar to that of DNAPL, the droplets are miscible with DNAPL. It is believed

Effect of dietary cadmium on iron metabolism in growing rats.

PubMed

Crowe, A; Morgan, E H

1997-07-01

Little is known regarding the interactions between iron and cadmium during postnatal development. This study examined the effect of altered levels of dietary iron and cadmium loading on the distribution of cadmium and iron in developing rats ages 15, 21, and 63 days. The uptake of iron, transferrin, and cadmium into various organs was also examined using 59Fe, [125I]transferrin, and 109Cd. Dietary cadmium loading reduced packed cell volume and plasma iron and nonheme iron levels in the liver and kidneys, evidence of the inducement of an iron deficient state. Dietary iron loading was able to reverse these effects, suggesting that they were the result of impaired intestinal absorption of iron. Cadmium loading resulted in cadmium concentrations in the liver and kidneys up to 20 microg/g in rats age 63 days, while cadmium levels in the brain reached only 0.16 microg/g, indicating that the blood-brain barrier restricts the entry of cadmium into the brain. Iron loading had little effect on cadmium levels in the organs and cadmium feeding did not lower tissue iron levels in iron loaded animals. These results suggest that cadmium inhibits iron absorption only at low to normal levels of dietary iron and that at high levels of intake iron and cadmium are largely absorbed by other, noncompetitive mechanisms. It was shown that 109Cd is removed from the plasma extremely quickly irrespective of iron status and deposits mainly in the liver. One of the most striking effects of cadmium loading on iron metabolism was increased uptake of [125I]transferrin by the heart, possibly by disrupting the process of receptor-mediated endocytosis and recycling of transferrin by heart muscle.

Microwave Magnetic Materials for Radar and Signal Processing Devices - Thin Film and Bulk Oxides and Metals

DTIC Science & Technology

2007-11-29

films, (3) low field effective linewidth in polycrystalline ferrites, (4) Fermi-Pasta-Ulam recurrence for spin wave solitons in yttrium iron garnet...Fermi- Pasta-Ulam recurrence for spin wave solitons in yttrium iron garnet (YIG) film strips in a feedback ring system, (5) the Hamiltonian...XRD data. point in field was so small that field modulation and lock -in The FMR field is taken at the peak loss point in the (b) detection methods

Iron status and anaemia in Sri Lankan secondary school children: A cross-sectional survey.

PubMed

Allen, Angela; Allen, Stephen; Rodrigo, Rexan; Perera, Lakshman; Shao, Wei; Li, Chao; Wang, Duolao; Olivieri, Nancy; Weatherall, David J; Premawardhena, Anuja

2017-01-01

Iron deficiency, the most common micronutrient disorder and cause of anaemia globally, impairs growth, cognition, behaviour and resistance to infection. As part of a national survey of inherited haemoglobin variants in 7526 students from 72 secondary schools purposefully selected from the 25 districts of Sri Lanka, we studied 5912 students with a normal haemoglobin genotype. Median age was 16.0 (IQR 15.0-17.0) years and 3189 (53.9%) students were males. Most students were Sinhalese (65.7%), with fewer Tamils (23.1%) and Muslims (11.2%). Anaemia occurred in 470 students and was more common in females (11.1%) than males (5.6%). Haemoglobin, serum ferritin, transferrin receptor and iron were determined in 1196 students with low red cell indices and a structured sample of those with normal red cell indices (n = 513). The findings were weighted to estimate the frequencies of iron deficiency and iron deficiency anaemia classified according to WHO criteria. Iron depletion (serum ferritin <15ug/ml) occurred in 19.2% and cellular iron deficiency (low serum ferritin and transferrin receptor >28.1 nmol/l) in 11.6% students. Iron deficiency anaemia (cellular iron deficiency with low haemoglobin) occurred in only 130/2794 (4.6%) females and 28/2789 (1.0%) males. Iron biomarkers were normal in 83/470 (14.6%) students with anaemia. In multiple regression analysis, the odds for iron depletion and cellular iron deficiency were about one-third in males compared with females, and the odds for iron deficiency anaemia were about one fifth in males compared to females. Tamil ethnicity and age <16 years increased the risk of all three stages of iron deficiency and living at high altitude significantly reduced the risk of iron depletion. Low iron status and anaemia remain common problems in Sri Lankan secondary school students especially females, younger students and the socioeconomically disadvantaged Tamil population. More research is needed to identify factors other than low iron status that contribute to anaemia in adolescents.

A review of the silicon material task

NASA Technical Reports Server (NTRS)

Lutwack, R.

1984-01-01

The Silicon Material Task of the Flat-Plate Solar Array Project was assigned the objective of developing the technology for low-cost processes for producing polysilicon suitable for terrestrial solar-cell applications. The Task program comprised sections for process developments for semiconductor-grade and solar-cell-grade products. To provide information for deciding upon process designs, extensive investigations of the effects of impurities on material properties and the performance of cells were conducted. The silane process of the Union Carbide Corporation was carried through several stages of technical and engineering development; a pilot plant was the culmination of this effort. The work to establish silane fluidized-bed technology for a low-cost process is continuing. The advantages of the use of dichlorosilane is a siemens-type were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

A review of the silicon material task

NASA Astrophysics Data System (ADS)

Lutwack, R.

1984-02-01

The Silicon Material Task of the Flat-Plate Solar Array Project was assigned the objective of developing the technology for low-cost processes for producing polysilicon suitable for terrestrial solar-cell applications. The Task program comprised sections for process developments for semiconductor-grade and solar-cell-grade products. To provide information for deciding upon process designs, extensive investigations of the effects of impurities on material properties and the performance of cells were conducted. The silane process of the Union Carbide Corporation was carried through several stages of technical and engineering development; a pilot plant was the culmination of this effort. The work to establish silane fluidized-bed technology for a low-cost process is continuing. The advantages of the use of dichlorosilane is a siemens-type were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

Hematite from Natural Iron Stones as Microwave Absorbing Material on X-Band Frequency Ranges

NASA Astrophysics Data System (ADS)

Zainuri, Mochamad

2017-05-01

This study has been investigated the effect of hematite as microwave absorbing materials (RAM) on X-Band frequency ranges. Hematite was succesfully processed by coprecipitation method and calcined at 500 °C for 5 hour. It was synthesized from natural iron stones from Tanah Laut, South Kalimantan, Indonesia. The products were characterized by X-ray diffraxtion (XRD), conductivity measurement, Vibrating Sample Magnetometer (VSM), and Vector Network Analyzer (VNA). The result was shown that hematite has conductivity value on (2.5-3).10-7 S/cm and be included as dielectric materials. The hysterisis curve was shown that hematite was a super paramagnetic materials. The product was mixed on paint with procentage 10% of total weight and coated on steel grade AH36 with spray methods. Then, the maximum of reflection loss on x - band’s frequency range (8,2-12,4) GHz was -7 dB on frequency of 10.5 GHz. It mean that almost 50% electromagnetic energy was absorbed by hematite.

Fe-Based Nano-Materials in Catalysis

PubMed Central

Konstantopoulos, Christos

2018-01-01

The role of iron in view of its further utilization in chemical processes is presented, based on current knowledge of its properties. The addition of iron to a catalyst provides redox functionality, enhancing its resistance to carbon deposition. FeOx species can be formed in the presence of an oxidizing agent, such as CO2, H2O or O2, during reaction, which can further react via a redox mechanism with the carbon deposits. This can be exploited in the synthesis of active and stable catalysts for several processes, such as syngas and chemicals production, catalytic oxidation in exhaust converters, etc. Iron is considered an important promoter or co-catalyst, due to its high availability and low toxicity that can enhance the overall catalytic performance. However, its operation is more subtle and diverse than first sight reveals. Hence, iron and its oxides start to become a hot topic for more scientists and their findings are most promising. The scope of this article is to provide a review on iron/iron-oxide containing catalytic systems, including experimental and theoretical evidence, highlighting their properties mainly in view of syngas production, chemical looping, methane decomposition for carbon nanotubes production and propane dehydrogenation, over the last decade. The main focus goes to Fe-containing nano-alloys and specifically to the Fe–Ni nano-alloy, which is a very versatile material. PMID:29772842

Quantifying VOC emissions from polymers: A case study

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

Schulze, J.K.; Qasem, J.S.; Snoddy, R.

1996-12-31

Evaluating residual volatile organic compound emissions emanating from low-density polyethylene can pose significant challenges. These challenges include quantifying emissions from: (a) multiple process lines with different operating conditions; (b) several different comonomers; (c) variations of comonomer content in each grade; and (d) over 120 grades of LDPE. This presentation is a Case Study outlining a project to develop grade-specific emission data for low-density polyethylene pellets. This study included extensive laboratory analyses and required the development of a relational database to compile analytical results, calculate the mean concentration and standard deviation, and generate emissions reports.

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.

Evidence that stainable bone marrow iron following parenteral iron therapy does not correlate with serum iron studies and may not represent readily available storage iron.

PubMed

Thomason, Ronald W; Almiski, Muhamad S

2009-04-01

We recently reported that parenteral iron therapy is associated with a characteristic pattern of iron staining on bone marrow aspirate smears. We now present clinical information from 6 patients who received parenteral iron and, at one or more points in follow-up, were found to have low or borderline low serum ferritin levels and/or serum iron levels, even though marrow aspirate smears revealed abundant stainable iron in the pattern characteristic of prior parenteral iron therapy. We conclude that stainable iron seen in this pattern does not correlate with serum iron studies and may not represent functionally available storage iron. This pattern of iron staining should not be used as evidence to withhold further iron therapy in patients who otherwise continue to have features of iron deficiency anemia.

Corrosion Resistance of a Cast-Iron Material Coated With a Ceramic Layer Using Thermal Spray Method

NASA Astrophysics Data System (ADS)

Florea, C. D.; Bejinariu, C.; Munteanu, C.; Istrate, B.; Toma, S. L.; Alexandru, A.; Cimpoesu, R.

2018-06-01

Cast-iron 250 used for breake systems present many corrosion signs after a mean usage time based on the environment conditions they work. In order to improve them corrosion resistance we propose to cover the active part of the material using a ceramic material. The deposition process is an industrial deposition system based on thermal spraying that can cover high surfaces in low time. In this articol we analyze the influence of a ceramic layer (40-50 µm) on the corrosion resistance of FC250 cast iron. The results were analyzed using scanning electron microscopy (SEM), X-ray energy dispersive (EDS) and linear and cyclic potentiometry.

What do we really know about the role of microorganisms in iron sulfide mineral formation?

USGS Publications Warehouse

Picard, Aude A.; Gartman, Amy; Girguis, Peter R.

2016-01-01

Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

River-derived humic substances as iron chelators in seawater

PubMed Central

Krachler, Regina; Krachler, Rudolf F.; Wallner, Gabriele; Hann, Stephan; Laux, Monika; Cervantes Recalde, Maria F.; Jirsa, Franz; Neubauer, Elisabeth; von der Kammer, Frank; Hofmann, Thilo; Keppler, Bernhard K.

2015-01-01

The speciation of iron(III) in oxic seawater is dominated by its hydrolysis and sedimentation of insoluble iron(III)-oxyhydroxide. As a consequence, many oceanic areas have very low iron levels in surface seawater which leads to iron deficiency since phytoplankton require iron as a micronutrient in order to grow. Fortunately, iron solubility is not truly as low as Fe(III) solubility measurements in inorganic seawater would suggest, since oceanic waters contain organic molecules which tend to bind the iron and keep it in solution. Various iron-binding organic ligands which combine to stabilize dissolved iron have been detected and thoroughly investigated in recent years. However, the role of iron-binding ligands from terrestrial sources remains poorly constrained. Blackwater rivers supply large amounts of natural organic material (NOM) to the ocean. This NOM (which consists mainly of vascular plant-derived humic substances) is able to greatly enhance iron bioavailability in estuaries and coastal regions, however, breakdown processes lead to a rapid decrease of river-derived NOM concentrations with increasing distance from land. It has therefore been argued that the influence of river-derived NOM on iron biogeochemistry in offshore seawater does not seem to be significant. Here we used a standard method based on 59Fe as a radiotracer to study the solubility of Fe(III)-oxyhydroxide in seawater in the presence of riverine NOM. We aimed to address the question how effective is freshwater NOM as an iron chelator under open ocean conditions where the concentration of land-derived organic material is about 3 orders of magnitude smaller than in coastal regions, and does this iron chelating ability vary between NOM from different sources and between different size fractions of the river-borne NOM. Our results show that the investigated NOM fractions were able to substantially enhance Fe(III)-oxyhydroxide solubility in seawater at concentrations of the NOM ≥ 5 μg L− 1. Terrigenous NOM concentrations ≥ 5 μg L− 1 are in no way unusual in open ocean surface waters especially of the Arctic and the North Atlantic Oceans. River-derived humic substances could therefore play a greater role as iron carriers in the ocean than previously thought. PMID:26412934

Differences and Comparisons of the Properties and Reactivities of Iron(III)–hydroperoxo Complexes with Saturated Coordination Sphere

PubMed Central

Faponle, Abayomi S; Quesne, Matthew G; Sastri, Chivukula V; Banse, Frédéric; de Visser, Sam P

2015-01-01

Heme and nonheme monoxygenases and dioxygenases catalyze important oxygen atom transfer reactions to substrates in the body. It is now well established that the cytochrome P450 enzymes react through the formation of a high-valent iron(IV)–oxo heme cation radical. Its precursor in the catalytic cycle, the iron(III)–hydroperoxo complex, was tested for catalytic activity and found to be a sluggish oxidant of hydroxylation, epoxidation and sulfoxidation reactions. In a recent twist of events, evidence has emerged of several nonheme iron(III)–hydroperoxo complexes that appear to react with substrates via oxygen atom transfer processes. Although it was not clear from these studies whether the iron(III)–hydroperoxo reacted directly with substrates or that an initial O–O bond cleavage preceded the reaction. Clearly, the catalytic activity of heme and nonheme iron(III)–hydroperoxo complexes is substantially different, but the origins of this are still poorly understood and warrant a detailed analysis. In this work, an extensive computational analysis of aromatic hydroxylation by biomimetic nonheme and heme iron systems is presented, starting from an iron(III)–hydroperoxo complex with pentadentate ligand system (L52). Direct C–O bond formation by an iron(III)–hydroperoxo complex is investigated, as well as the initial heterolytic and homolytic bond cleavage of the hydroperoxo group. The calculations show that [(L52)FeIII(OOH)]2+ should be able to initiate an aromatic hydroxylation process, although a low-energy homolytic cleavage pathway is only slightly higher in energy. A detailed valence bond and thermochemical analysis rationalizes the differences in chemical reactivity of heme and nonheme iron(III)–hydroperoxo and show that the main reason for this particular nonheme complex to be reactive comes from the fact that they homolytically split the O–O bond, whereas a heterolytic O–O bond breaking in heme iron(III)–hydroperoxo is found. PMID:25399782

New insights into iron acquisition by cyanobacteria: an essential role for ExbB-ExbD complex in inorganic iron uptake

PubMed Central

Jiang, Hai-Bo; Lou, Wen-Jing; Ke, Wen-Ting; Song, Wei-Yu; Price, Neil M; Qiu, Bao-Sheng

2015-01-01

Cyanobacteria are globally important primary producers that have an exceptionally large iron requirement for photosynthesis. In many aquatic ecosystems, the levels of dissolved iron are so low and some of the chemical species so unreactive that growth of cyanobacteria is impaired. Pathways of iron uptake through cyanobacterial membranes are now being elucidated, but the molecular details are still largely unknown. Here we report that the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 contains three exbB-exbD gene clusters that are obligatorily required for growth and are involved in iron acquisition. The three exbB-exbDs are redundant, but single and double mutants have reduced rates of iron uptake compared with wild-type cells, and the triple mutant appeared to be lethal. Short-term measurements in chemically well-defined medium show that iron uptake by Synechocystis depends on inorganic iron (Fe′) concentration and ExbB-ExbD complexes are essentially required for the Fe′ transport process. Although transport of iron bound to a model siderophore, ferrioxamine B, is also reduced in the exbB-exbD mutants, the rate of uptake at similar total [Fe] is about 800-fold slower than Fe′, suggesting that hydroxamate siderophore iron uptake may be less ecologically relevant than free iron. These results provide the first evidence that ExbB-ExbD is involved in inorganic iron uptake and is an essential part of the iron acquisition pathway in cyanobacteria. The involvement of an ExbB-ExbD system for inorganic iron uptake may allow cyanobacteria to more tightly maintain iron homeostasis, particularly in variable environments where iron concentrations range from limiting to sufficient. PMID:25012898

In vivo anti-radiation activities of the Ulva pertusa polysaccharides and polysaccharide-iron(III) complex.

PubMed

Shi, Jinming; Cheng, Cuilin; Zhao, Haitian; Jing, Jing; Gong, Ning; Lu, Weihong

2013-09-01

Polysaccharides with different molecular weights were extracted from Ulva pertusa and fractionated by ultrafiltration. Iron(III) complex of the low molecular-weight U. pertusa polysaccharides were synthesized. Atomic absorption spectrum showed that the iron content of iron(III)-polysaccharide complex was 27.4%. The comparison between U. pertusa polysaccharides and their iron(III) complex showed that iron chelating altered the structural characteristics of the polysaccharides. The bioactivity analysis showed that polysaccharide with low molecular weight was more effective than polysaccharide with high molecular weight in protecting mice from radiation induced damages on bone marrow cells and immune system. Results also proved that the anti-radiation and anti-oxidative activity of iron(III) complex of low molecular-weight polysaccharides were not less than that of low molecular-weight polysaccharides. Copyright © 2013 Elsevier B.V. All rights reserved.

Repair welding of cast iron coated electrodes

NASA Astrophysics Data System (ADS)

Żuk, M.; Górka, J.; Dojka, R.; Czupryński, A.

2017-08-01

Welding cast iron is a complex production procedure. Repair welding was used to repair damaged or poorly made castings. This is due to a tendency to cracking of the material during welding as well as after it. Welding cast iron can be carried out on hot or on cold. Hot welding requires high heat material and the use of welding material in the form of cast iron. In the case of cold welding, it is possible to use different materials. Mostly used filler metals are nickel and copper based. The work shows the course of research concerning repairmen of ductile iron with arc welding method. For the reparation process four types of ESAB company coated electrodes dedicated for cast iron were used with diameter 3.2 and 4 mm: ES 18-8-6B (4mm), EB 150 (4mm), OK NiCl, EŻM. In the cast iron examined during the testing grooves were made using plasma methods, in order to simulate the removed casting flaws. Then the welding process with coated electrodes was executed. The process utilized low welding current row of 100A, so there would only be a small amount of heat delivered to the heat affected zone (HAZ). Short stitches were made, after welding it was hammered, in order to remove stresses. After the repair welding the part of studies commenced which purpose was finding surface defects using visual testing (VT) and penetration testing (PT). In the second part, a series of macro and microscopic studies were executed witch the purpose of disclosuring the structure. Then the hardness tests for welds cross sections were performed. An important aspect of welding cast iron is the colour of the padding weld after welding, more precisely the difference between the base material and padding weld, the use of different materials extra gives the extra ability to select the best variant. The research of four types of coated electrode was executed, based on the demands the best option in terms of aesthetic, strength and hardness.

Nutritional and functional characteristics of seven grades of black tea produced in Turkey.

PubMed

Serpen, Arda; Pelvan, Ebru; Alasalvar, Cesarettin; Mogol, Burçe Ataç; Yavuz, Havvana Tuba; Gökmen, Vural; Özcan, Nihat; Özçelik, Beraat

2012-08-08

Seven grades of black tea [high-quality black tea (grades 1-3) and low-quality black tea (grades 4-7)], processed by ÇAYKUR Tea Processing Plant (Rize, Turkey), were examined for their proximate composition, dietary fiber, minerals, and water-soluble vitamins as well as total phenolic content, various antioxidant assays, phenolics (flavanols, alkoloids, condensed phenolics, and phenolic acids), chlorophylls, and carotenoids. Some variations, albeit to different extents, were observed (p < 0.05) among these parameters in seven grades of black tea. With respect to proximate composition, dietary fiber was the predominant compound (ranging from 49.68 to 54.31 g/100 g), followed by protein, carbohydrate, and, to a lesser extent, ash, moisture, and fat. Thirteen minerals, four water-soluble vitamins, six flavanols, two alkoloids, three condensed phenolics, one phenolic acid, two chlorophylls, and two carotenoids were identified in the seven grades of black tea. Total phenol content ranged from 7.52 to 8.29 g of gallic acid equivalents (GAE)/100 g, being lowest in grade 6 and highest in grade 1. With regard to antioxidant activities, a large variation in oxygen radical absorbance capacity (ORAC) values was observed among all grades of black tea (ranging from 777 μmol of trolox equivalents (TE)/g in grade 7 to 1210 μmol of TE/g in grade 3). The present work suggests that high- and low-quality black teas should not be distinguished on the basis of their nutritional and functional characteristics. The combination of nutritional compounds together with functional characteristics renders combination effects that provide the characteristic quality of each grade of black tea.

High-Iron Consumption Impairs Growth and Causes Copper-Deficiency Anemia in Weanling Sprague-Dawley Rats

PubMed Central

Ha, Jung-Heun; Doguer, Caglar; Wang, Xiaoyu; Flores, Shireen R.; Collins, James F.

2016-01-01

Iron-copper interactions were described decades ago; however, molecular mechanisms linking the two essential minerals remain largely undefined. Investigations in humans and other mammals noted that copper levels increase in the intestinal mucosa, liver and blood during iron deficiency, tissues all important for iron homeostasis. The current study was undertaken to test the hypothesis that dietary copper influences iron homeostasis during iron deficiency and iron overload. We thus fed weanling, male Sprague-Dawley rats (n = 6-11/group) AIN-93G-based diets containing high (~8800 ppm), adequate (~80) or low (~11) iron in combination with high (~183), adequate (~8) or low (~0.9) copper for 5 weeks. Subsequently, the iron- and copper-related phenotype of the rats was assessed. Rats fed the low-iron diets grew slower than controls, with changes in dietary copper not further influencing growth. Unexpectedly, however, high-iron (HFe) feeding also impaired growth. Furthermore, consumption of the HFe diet caused cardiac hypertrophy, anemia, low serum and tissue copper levels and decreased circulating ceruloplasmin activity. Intriguingly, these physiologic perturbations were prevented by adding extra copper to the HFe diet. Furthermore, higher copper levels in the HFe diet increased serum nonheme iron concentration and transferrin saturation, exacerbated hepatic nonheme iron loading and attenuated splenic nonheme iron accumulation. Moreover, serum erythropoietin levels, and splenic erythroferrone and hepatic hepcidin mRNA levels were altered by the dietary treatments in unanticipated ways, providing insight into how iron and copper influence expression of these hormones. We conclude that high-iron feeding of weanling rats causes systemic copper deficiency, and further, that copper influences the iron-overload phenotype. PMID:27537180

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

S.A. Feshchenko; V.I. Pleshkov; I.N. Shishchuk

To reduce the costs of blast-furnace smelting, the Svobodnyi Sokol plant has devised a comprehensive program of organizational-technical measures that include study of ways of reducing coke consumption. To do this, the plant began operating its blast furnaces with schungite when making foundry and conversion pig irons. Using schungite in the charge employed to make foundry iron makes it possible to save a significant (10-15%) amount of coke. The value of the coefficient that characterizes the replacement of coke by schungite varies broadly and can reach 1.0 or more, depending on the grade of iron being made and the furnacemore » operating regime. The same coefficient has a value of 0.57 kg coke/kg schungite when 12-15 kg schungite/ton pig is used to make conversion pig iron.« less

[The efficacy of phlebotomy with a low iron diet in the management of pulmonary iron overload].

PubMed

Fukuda, Tomoko; Kimura, Fumiaki; Watanabe, Yoichi; Yoshino, Tadasi; Kimura, Ikuro

2003-05-01

Numerous studies have shown that workers in ferriferous industries have an elevated risk of respiratory tract neoplasia and other airway diseases. Evidence is presented that iron is a carcinogenic and tissue toxic hazard as regarding the inhalation of ferriferous substances. Elimination of the inhaled iron and prevention from accumulation of iron in the lung seems to be very important. A 26-year-old man was admitted to our hospital complaining of right chest pain. He had worked as an arc welder for two years without a mask. A chest CT showed diffuse ground glass opacity in the bilateral lung fields. A transbronchial lung biopsy specimen showed numerous alveolar and interstitial iron-laden macrophages. A 200 ml phlebotomy was carried out biweekly in combination with a low iron diet (8 mg/day). When serum ferritin reached 20 ng/ml, phlebotomy was stopped. After that, serum ferritin level was kept at around 20 ng/ml with the low iron diet alone. A transbronchial lung biopsy was carried out again 7 months later and the specimen showed remarkable reduction in the number of iron-laden alveolar and interstitial macrophages. Phlebotomy in combination with a low iron diet might become a useful strategy in the management of pulmonary conditions associated with iron loading.

Characterisation and Processing of Some Iron Ores of India

NASA Astrophysics Data System (ADS)

Krishna, S. J. G.; Patil, M. R.; Rudrappa, C.; Kumar, S. P.; Ravi, B. P.

2013-10-01

Lack of process characterization data of the ores based on the granulometry, texture, mineralogy, physical, chemical, properties, merits and limitations of process, market and local conditions may mislead the mineral processing entrepreneur. The proper implementation of process characterization and geotechnical map data will result in optimized sustainable utilization of resource by processing. A few case studies of process characterization of some Indian iron ores are dealt with. The tentative ascending order of process refractoriness of iron ores is massive hematite/magnetite < marine black iron oxide sands < laminated soft friable siliceous ore fines < massive banded magnetite quartzite < laminated soft friable clayey aluminous ore fines < massive banded hematite quartzite/jasper < massive clayey hydrated iron oxide ore < manganese bearing iron ores massive < Ti-V bearing magnetite magmatic ore < ferruginous cherty quartzite. Based on diagnostic process characterization, the ores have been classified and generic process have been adopted for some Indian iron ores.

Pyrimethanil degradation by photo-Fenton process: Influence of iron and irradiance level on treatment cost.

PubMed

Cabrera Reina, A; Miralles-Cuevas, S; Casas López, J L; Sánchez Pérez, J A

2017-12-15

This study evaluates the combined effect of photo-catalyst concentration and irradiance level on photo-Fenton efficiency when this treatment is applied to industrial wastewater decontamination. Three levels of irradiance (18, 32 and 46W/m 2 ) and three iron concentrations (8, 20 and 32mg/L) were selected and their influence over the process studied using a raceway pond reactor placed inside a solar box. For 8mg/L, it was found that there was a lack of catalyst to make use of all the available photons. For 20mg/L, the treatment always improved with irradiance indicating that the process was photo-limited. For 32mg/L, the excess of iron caused an excess of radicals production which proved to be counter-productive for the overall process efficiency. The economic assessment showed that acquisition and maintenance costs represent the lowest relative values. The highest cost was found to be the cost of the reagents consumed. Both sulfuric acid and sodium hydroxide are negligible in terms of costs. Iron cost percentages were also very low and never higher than 10.5% while the highest cost was always that of hydrogen peroxide, representing at least 85% of the reagent costs. Thus, the total costs were between 0.76 and 1.39€/m 3 . Copyright © 2017 Elsevier B.V. All rights reserved.

Zinc toxicity among galvanization workers in the iron and steel industry.

PubMed

El Safty, Amal; El Mahgoub, Khalid; Helal, Sawsan; Abdel Maksoud, Neveen

2008-10-01

Galvanization is the process of coating steel or cast iron pieces with zinc, allowing complete protection against corrosion. The ultimate goal of this work was to assess the effect of occupational exposure to zinc in the galvanization process on different metals in the human body and to detect the association between zinc exposure and its effect on the respiratory system. This study was conducted in 111 subjects in one of the major companies in the iron and steel industry. There were 61 subjects (workers) who were involved in the galvanization process. Fifty adult men were chosen as a matched reference group from other departments of the company. All workers were interviewed using a special questionnaire on occupational history and chest diseases. Ventilatory functions and chest X rays were assessed in all examined workers. Also, complete blood counts were performed, and serum zinc, iron, copper, calcium, and magnesium levels were tested. This study illustrated the relation between zinc exposure in the galvanization process and high zinc levels among exposed workers, which was associated with a high prevalence rate of metal fume fever (MFF) and low blood copper and calcium levels. There was no statistically significant difference between the exposed and control groups with regards to the magnesium level. No long-term effect of metals exposure was detected on ventilatory functions or chest X rays among the exposed workers.

Low Prevalence of Iron and Vitamin A Deficiency among Cambodian Women of Reproductive Age

PubMed Central

Wieringa, Frank T.; Sophonneary, Prak; Whitney, Sophie; Mao, Bunsoth; Berger, Jacques; Conkle, Joel; Dijkhuizen, Marjoleine A.; Laillou, Arnaud

2016-01-01

Nearly half of women of reproductive age (WRA) in Cambodia are anemic. To guide interventions, national data on nutritional causes of anemia, including iron deficiency and vitamin A deficiency, are needed. In 2012, a national household survey in WRA on antibodies to routine vaccine-preventable disease immunity was performed. We used serum samples from this survey to estimate the prevalence of iron and vitamin A deficiency in 2112 Cambodian WRA, aged 15 to 39 years. Iron deficiency was classified as low or marginal iron stores (ferritin concentrations corrected for inflammation <15 μg/L and <50 μg/L respectively; Fer), iron deficient erythropoiesis (soluble transferrin receptor concentrations >8.3 mg/L; sTfR), or low total body iron (TBI) derived from Fer and sTfR concentrations (<0 mg/kg). Vitamin A status was classified using retinol binding protein (RBP) concentrations corrected for inflammation as deficient (<0.70 μmol/L) or marginal (<1.05 μmol/L. Overall, the prevalence of low iron stores, low TBI and iron deficient erythropoiesis was 8.1%, 5.0% and 9.3% respectively. Almost 40% of the women had marginal iron stores. Iron status was better in women living in urban areas compared to rural areas (p < 0.05 for TBI and sTfR). The prevalence of vitamin A deficiency was <1%. These findings suggest that the contribution of iron and vitamin A deficiency to the high prevalence of anemia in Cambodian WRA may be limited. The etiology of anemia in Cambodia needs to be elucidated further to guide current policies on anemia. PMID:27043624

Investigation of the mechanisms of membrane fouling by intracellular organic matter under different iron treatments during ultrafiltration.

PubMed

Huang, Weiwei; Qin, Xiao; Dong, Bingzhi; Zhou, Wenzong; Lv, Weiguang

2018-05-30

Iron is an important trace element in algal growth and water eutrophication. This study focused on the ultrafiltration (UF) membrane fouling mechanism by the intracellular organic matter (IOM) of Microcystis aeruginosa under different iron treatments. The results indicated that the membranes experienced faster flux decline and worse fouling reversibility when the IOM formed under low iron concentrations. In contrast, less IOM membrane fouling was found under normal and high iron concentrations. The mass balances of the dissolved organic carbon (DOC) content implied that the IOM in the low-iron treatment was associated with higher IOM retention and a higher capacity of reversibly deposited organics, whereas more IOM in the high-iron treatment passed through the UF membrane. The IOM in the low-iron treatment was composed of more biopolymer macromolecules, whereas the IOM in the high-iron treatment contained more UV-absorbing hydrophobic organics. The fluorescence excitation-emission matrix (EEM) spectra coupled with peak-fitting analysis implied that the fouling associated with protein-like components was more irreversible in the low-iron treatment than those in the normal- and high-iron treatments. Cake formation combined with intermediate blocking was identified as the main membrane fouling mechanism responsible for the flux decline caused by IOM solutions in the three iron treatments in this study. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterizing the production and retention of dissolved iron as Fe(II) across a natural gradient in chlorophyll concentrations in the Southern Drake Passage - Final Technical Report

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

Katherine Barbeau

2007-04-10

Recent mesoscale iron fertilization studies in the Southern Ocean (e.g. SOIREE, EisenEx, SOFeX) have demonstrated the importance of iron as a limiting factor for phytoplankton growth in these high nutrient, low-chlorophyll (HNLC) waters. Results of these experiments have demonstrated that factors which influence the biological availability of the iron supplied to phytoplankton are crucial in bloom development, longevity, and generation of carbon export flux. These findings have important implications for the future development of iron fertilization protocols to enhance carbon sequestration in high-latitude oceans. In particular, processes which lead to the mobilization and retention of iron in dissolved form inmore » the upper ocean are important in promoting continued biological availability of iron. Such processes can include photochemical redox cycling, which leads to the formation of soluble reduced iron, Fe(II), within iron-enriched waters. Creation of effective fertilization schemes will thus require more information about Fe(II) photoproduction in Southern Ocean waters as a means to retain new iron within the euphotic zone. To contribute to our knowledge base in this area, this project was funded by DOE with a goal of characterizing the production and retention of dissolved Fe as Fe(II) in an area of the southern Drake Passage near the Shackleton Transverse Ridge, a region with a strong recurrent chlorophyll gradient which is believed to be a site of natural iron enrichment in the Southern Ocean. This area was the focus of a multidisciplinary NSF/OPP-funded investigation in February 2004 (OPP02-30443, lead PI Greg Mitchell, SIO/UCSD) to determine the influence of mesoscale circulation and iron transport with regard to the observed patterns in sea surface chlorophyll in the region near the Shackleton Transverse Ridge. A number of parameters were assessed across this gradient in order to reveal interactions between plankton community structure and iron distributions. As a co-PI in the NSF/OPP-funded project, I was responsible for iron addition incubation and radiotracer experiments, and analysis of iron chemistry, including iron-organic speciation. This final technical report describes the results of my DOE funded project to analyse reduced iron species using an FeLume flow injection analysis chemiluminescence system as an extension of my work on the NSF/OPP project. On the cruise in 2004, spatial and temporal gradients in Fe(II) were determined, and on-board incubations were conducted to study Fe(II) lifetime and production. Following the cruise a further series of experiments was conducted in my laboratory to study Fe(II) lifetimes and photoproduction under conditions typical of high latitude waters. The findings of this study suggest that, in contrast to results observed during mesoscale iron addition experiments, steady-state levels of Fe(II) are likely to remain low (below detection) even within a significant gradient in dissolved Fe concentrations produced as a result of natural iron enrichment processes. Fe(II) is likely to be produced, however, as a reactive intermediate associated with photochemical reactions in surface waters. While Fe(II) lifetimes measured in the field in this study were commensurate with those determined in previously published Southern Ocean work, Fe(II) lifetimes reflective of realistic Southern Ocean environmental conditions have proven difficult to determine in a laboratory setting, due to contamination by trace levels of H2O2. Laboratory experiments demonstrated that direct ligand-to-metal charge transfer reactions of strong Fe(III)-organic complexes do appear to be a viable source of available Fe(II) in Antarctic waters, and further studies are needed to characterize the temperature dependence of this phenomenon.« less

Iron-ore resources of the United States including Alaska and Puerto Rico, 1955

USGS Publications Warehouse

Carr, Martha S.; Dutton, Carl E.

1959-01-01

The importance of iron ore, the basic raw material of steel, as a fundamental mineral, resource is shown by the fact that about 100 million long tons of steel is used annually in the economy of the United States, as compared with a combined total of about 5 million long tons of copper, lead, zinc, and aluminum. Satisfying this annual demand for steel requires about 110 million tons of iron ore and 70 million tons of scrap iron and steel. The average annual consumption of iron ore in the United States from 1951 to 1955, inclusive, was about 110 million long tons, which is about twice the annual average from 1900 to 1930. Production of iron ore in the United States in this 5-year period averaged approximately 100 million long tons annually, divided by regions as follows (in percent): Lake Superior, 84.1; southeastern, 6.7; western, 6.7; northeastern, 1.4; and central and gulf, 1.1. Mining of iron ore began in the American Colonies about 1619, and for 225 years it was limited to eastern United States where fuel and markets were readily available. Production of iron ore from the Lake Superior region began in 1846; the region became the leading domestic source by 1890, and the Mesabi range in Minnesota has been the world's most productive area since 1896. Proximity of raw materials, water transportation, and markets has resulted in centralization of the country's iron and steel industry in the lower Great Lakes area. Increased imports of iron ore being delivered to eastern United States as well as demands for steel in nearby markets have given impetus to expansion in the steel-making capacity in this area. The four chief iron-ore minerals - hematite, liminite, magnetite, and siderite - are widely distributed but only locally form deposits of sufficient tonnage and grade to be commercially valuable at the present time. The iron content of these minerals, of which hematite is the most important, ranges from 48 percent in siderite to 72 percent in magnetite, but as these minerals are associated with other rock-forming minerals, the iron content of marketable ore has a lower range from 30 to 67 percent.Chemical constituents other than iron also are important in determining the marketability of iron ore. Although some iron ores can be used in the blast furnace as mined, others must first be improved either chemically by reduction of undesirable constituents, or physically by aggregation. Phosphorus and sulfur particularly are common deleterious elements; excessive silica is also undesirable but within certain limits can be controlled by additional flux. Lime and magnesia are beneficial in specified amounts because of their fluxing qualities, and a small amount of alumina improves the fluidity of slag. Manganese is especially desirable as a deoxidizing and desulfurizing agent. Titanium, chromium, and nickel must also be considered in the use of ore containing these elements.The principal iron-ore deposits in the United States have been formed by three processes. Hematite-bearing bedded deposits such as those at Birmingham, Ala., are marine sedimentary rocks which, except for weathering along the outcrop, have remained practically unaltered since deposition. Deposits of the Lake Superior region, also in sedimentary strata, originally had a slightly lower iron content than those at-Birmingham, but ore bodies of hematite and limonite were formed by removal of other constituents in solution after deposition of the beds, with a relative increase of iron content in the material remaining. Limestone adjacent to igneous intrusions has been replaced by magnetite deposits at Cornwall, Pa., and by hematite-magnetite deposits near Cedar City, Utah. Magnetite deposits in New Jersey and in the Adirondack Mountains of New York are generally believed to have been formed by replacement of grains of other minerals in metamorphic rocks. Iron-ore resources are made up of reserves of iron ore, material usable under existing economic and technologic conditions; and potential ore, material likely to become usable under more favorable conditions. The tonnage and grade of material of combined reserves and potential ore in each of the deposits known or believed to contain at least 200,000 long tons of iron-ore resources are tabulated in this report, and numerous sources of additional information are given in a selected bibliography. The total domestic iron-ore resources are estimated at approximately 75,000 million long tons of crude ore. About 10,000 million tons of the resources is reserves of crude ore that will probably yield 5,500 million tons of concentrates and direct-shipping ore. About 65,000 million tons is potential ore and may yield 25,000 million tons of concentrates and some direct-shipping ore.

From Pore to Core: Do Engineered Nanoparticles Violate Upscaling Assumptions? A Microtomographic Investigation

NASA Astrophysics Data System (ADS)

Molnar, I. L.; O'Carroll, D. M.; Gerhard, J.; Willson, C. S.

2014-12-01

The recent success in using Synchrotron X-ray Computed Microtomography (SXCMT) for the quantification of nanoparticle concentrations within real, three-dimensional pore networks [1] has opened up new opportunities for collecting experimental data of pore-scale flow and transport processes. One opportunity is coupling SXCMT with nanoparticle/soil transport experiments to provide unique insights into how pore-scale processes influence transport at larger scales. Understanding these processes is a key step in accurately upscaling micron-scale phenomena to the continuum-scale. Upscaling phenomena from the micron-scale to the continuum-scale typically involves the assumption that the pore space is well mixed. Using this 'well mixed assumption' it is implicitly assumed that the distribution of nanoparticles within the pore does not affect its retention by soil grains. This assumption enables the use of volume-averaged parameters in calculating transport and retention rates. However, in some scenarios, the well mixed assumption will likely be violated by processes such as deposition and diffusion. These processes can alter the distribution of the nanoparticles in the pore space and impact retention behaviour, leading to discrepancies between theoretical predictions and experimental observations. This work investigates the well mixed assumption by employing SXCMT to experimentally examine pore-scale mixing of silver nanoparticles during transport through sand packed columns. Silver nanoparticles were flushed through three different sands to examine the impact of grain distribution and nanoparticle retention rates on mixing: uniform silica (low retention), well graded silica sand (low retention) and uniform iron oxide coated silica sand (high retention). The SXCMT data identified diffusion-limited retention as responsible for violations of the well mixed assumption. A mathematical description of the diffusion-limited retention process was created and compared to the experimental data at the pore and column-scale. The mathematical description accurately predicted trends observed within the SXCMT-datasets such as concentration gradients away from grain surfaces and also accurately predicted total retention of nanoparticles at the column scale. 1. ES&T 2014, 48, (2), 1114-1122.

Appearance of Membrane-bound Iron-Sulfur Centers and the Photosystem I Reaction Center during Greening of Barley Leaves 1

PubMed Central

Baltimore, Barbara G.; Malkin, Richard

1977-01-01

Dark-grown barley (Hordeum vulgare) etioplasts were examined for their content of membrane-bound iron-sulfur centers by electron paramagnetic resonance spectroscopy at 15K. They were found to contain the high potential iron-sulfur center characterized (in the reduced state) by an electron paramagnetic resonance g value of 1.89 (the “Rieske” center) but did not contain any low potential iron-sulfur centers. Per mole of cytochrome f, dark-grown etioplasts and fully developed chloroplasts had the same content of the Rieske center. During greening of etioplasts under continuous light, low potential bound iron-sulfur centers appear. In addition, the photosystem I reaction center, as measured by the photooxidation of P700 at 15K, also became functional; during greening the appearance of a photoreducible low potential iron-sulfur center paralleled the appearance of P700 photoactivity. These findings indicate the close association of the low potential iron-sulfur centers with the photosystem I reaction center; they also support the concept that the development of stable charge separation in the photosystem I reaction center requires, in addition to P700, a low potential iron-sulfur center. PMID:16660048

Hepcidin expression does not rescue the iron-poor phenotype of Kupffer cells in Hfe-null mice after liver transplantation.

PubMed

Garuti, Cinzia; Tian, Yinghua; Montosi, Giuliana; Sabelli, Manuela; Corradini, Elena; Graf, Rolf; Ventura, Paolo; Vegetti, Alberto; Clavien, Pierre-Alain; Pietrangelo, Antonello

2010-07-01

Hemochromatosis is a common hereditary disease caused by mutations in HFE and characterized by increased absorption of iron in the intestine. However, the intestine does not appear to be the site of mutant HFE activity in the disease; we investigated the role of the liver-the source of the iron regulatory hormone hepcidin-in pathogenesis in mice. We exchanged livers between Hfe wild-type (+/+) and Hfe null (-/-) mice by orthotopic liver transplantation (OLT) and assessed histopathology, serum and tissue iron parameters, and hepatic hepcidin messenger RNA expression. At 6-8 months after OLT, Hfe(-/-) mice that received Hfe(-/-) livers maintained the hemochromatosis phenotype: iron accumulation in hepatocytes but not Kupffer cells (KC), increased transferrin levels, and low levels of iron in the spleen. Hfe(+/+) mice that received Hfe(-/-) livers had increased levels of iron in serum and liver and low levels of iron in spleen. However, they did not develop the iron-poor KCs that characterize hemochromatosis: KCs appeared iron rich, although hepatic hepcidin expression was low. Transplantation of Hfe(+/+) livers into Hfe(-/-) mice prevented hepatic iron accumulation but did not return spleen and plasma levels of iron to normal; KCs still appeared to be iron poor, despite normal hepcidin expression. In Hfe(-/-) mice, transplantation of livers from Hfe(+/+) mice reversed the iron-loading phenotype associated with hemochromatosis (regardless of Hfe expression in intestine). However, KCs still had low levels of iron that were not affected by hepatic hepcidin expression. These findings indicate an independent, iron-modifying effect of HFE in KCs. Copyright 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.

Multivariate analysis of the heterogeneous geochemical processes controlling arsenic enrichment in a shallow groundwater system.

PubMed

Huang, Shuangbing; Liu, Changrong; Wang, Yanxin; Zhan, Hongbin

2014-01-01

The effects of various geochemical processes on arsenic enrichment in a high-arsenic aquifer at Jianghan Plain in Central China were investigated using multivariate models developed from combined adaptive neuro-fuzzy inference system (ANFIS) and multiple linear regression (MLR). The results indicated that the optimum variable group for the AFNIS model consisted of bicarbonate, ammonium, phosphorus, iron, manganese, fluorescence index, pH, and siderite saturation. These data suggest that reductive dissolution of iron/manganese oxides, phosphate-competitive adsorption, pH-dependent desorption, and siderite precipitation could integrally affect arsenic concentration. Analysis of the MLR models indicated that reductive dissolution of iron(III) was primarily responsible for arsenic mobilization in groundwaters with low arsenic concentration. By contrast, for groundwaters with high arsenic concentration (i.e., > 170 μg/L), reductive dissolution of iron oxides approached a dynamic equilibrium. The desorption effects from phosphate-competitive adsorption and the increase in pH exhibited arsenic enrichment superior to that caused by iron(III) reductive dissolution as the groundwater chemistry evolved. The inhibition effect of siderite precipitation on arsenic mobilization was expected to exist in groundwater that was highly saturated with siderite. The results suggest an evolutionary dominance of specific geochemical process over other factors controlling arsenic concentration, which presented a heterogeneous distribution in aquifers. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A, to view the supplemental file.

Removal of pharmaceuticals from MWTP effluent by nanofiltration and solar photo-Fenton using two different iron complexes at neutral pH.

PubMed

Miralles-Cuevas, S; Oller, I; Pérez, J A Sánchez; Malato, S

2014-11-01

In recent years, membrane technologies (nanofiltration (NF)/reverse osmosis (RO)) have received much attention for micropollutant separation from Municipal Wastewater Treatment Plant (MWTP) effluents. Practically all micropollutants are retained in the concentrate stream, which must be treated. Advanced Oxidation Processes (AOPs) have been demonstrated to be a good option for the removal of microcontaminants from water systems. However, these processes are expensive, and therefore, are usually combined with other techniques (such as membrane systems) in an attempt at cost reduction. One of the main costs in solar photo-Fenton comes from reagent consumption, mainly hydrogen peroxide and chemicals for pH adjustment. Thus, in this study, solar photo-Fenton was used to treat a real MWTP effluent with low initial iron (less than 0.2 mM) and hydrogen peroxide (less than 2 mM) concentrations. In order to work at neutral pH, iron complexing agents (EDDS and citrate) were used in the two cases studied: direct treatment of the MWTP effluent and treatment of the concentrate stream generated by NF. The degradation of five pharmaceuticals (carbamazepine, flumequine, ibuprofen, ofloxacin and sulfamethoxazole) spiked in the effluent at low initial concentrations (μg L(-1)) was monitored as the main variable in the pilot-plant-scale photo-Fenton experiments. In both effluents, pharmaceuticals were efficiently removed (>90%), requiring low accumulated solar energy (2 kJUV L(-1), key parameter in scaling up the CPC photoreactor) and low iron and hydrogen peroxide concentrations (reagent costs, 0.1 and 1.5 mM, respectively). NF provided a clean effluent, and the concentrate was positively treated by solar photo-Fenton with no significant differences between the direct MWTP effluent and NF concentrate treatments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of different home-cooking methods on the bioaccessibility of zinc and iron in conventionally bred cowpea (Vigna unguiculata L. Walp) consumed in Brazil.

PubMed

Pereira, Elenilda J; Carvalho, Lucia M J; Dellamora-Ortiz, Gisela M; Cardoso, Flávio S N; Carvalho, José L V

2016-01-01

The cowpea (Vigna unguiculata L. Wap.) is an excellent source of iron and zinc. However, iron from plant sources is poorly absorbed compared with iron from animal sources. The objective of this study was to evaluate iron and zinc bioaccessibility in cowpea cultivars after processing. Zinc and iron bioaccessibilities in cowpea samples were determined based on an in vitro method involving simulated gastrointestinal digestion with suitable modifications. When water-soaked beans were cooked in a regular pan, the highest percentage of bioaccessible iron obtained was 8.92%, whereas when they were cooked in a pressure cooker without previous soaking, the highest percentage was 44.33%. Also, the percentage of bioaccessible zinc was 52.78% when they were cooked in a regular pan without prior soaking. Higher percentages of bioaccessible iron were found when cooking was done in a pressure cooker compared with regular pan cooking. In all cultivars, cooking of cowpea beans in both pressure cooker and in a regular pan yielded higher percentages of bioaccessible zinc compared with availability of bioaccessible iron. Iron bioaccessibility values suggest that cooking in a regular pan did not have a good effect on iron availability, since the percentage of bioaccessible iron was lower than that of zinc. The determination of iron and zinc bioaccessibility makes it possible to find out the actual percentage of absorption of such minerals and allows the development of efficient strategies for low-income groups to access foods with high levels of these micronutrients.

Heme iron uptake by Caco-2 cells is a saturable, temperature sensitive and modulated by extracellular pH and potassium.

PubMed

Arredondo, Miguel; Kloosterman, Janneke; Núñez, Sergio; Segovia, Fabián; Candia, Valeria; Flores, Sebastián; Le Blanc, Solange; Olivares, Manuel; Pizarro, Fernando

2008-11-01

It is known that heme iron and inorganic iron are absorbed differently. Heme iron is found in the diet mainly in the form of hemoglobin and myoglobin. The mechanism of iron absorption remains uncertain. This study focused on the heme iron uptake by Caco-2 cells from a hemoglobin digest and its response to different iron concentrations. We studied the intracellular Fe concentration and the effect of time, K+ depletion, and cytosol acidification on apical uptake and transepithelial transport in cells incubated with different heme Fe concentrations. Cells incubated with hemoglobin-digest showed a lower intracellular Fe concentration than cells grown with inorganic Fe. However, uptake and transepithelial transport of Fe was higher in cells incubated with heme Fe. Heme Fe uptake had a low Vmax and Km as compared to inorganic Fe uptake and did not compete with non-heme Fe uptake. Heme Fe uptake was inhibited in cells exposed to K+ depletion or cytosol acidification. Heme oxygenase 1 expression increased and DMT1 expression decreased with higher heme Fe concentrations in the media. The uptake of heme iron is a saturable and temperature-dependent process and, therefore, could occur through a mechanism involving both a receptor and the endocytic pathway.

The removal of arsenate from water using iron-modified diatomite (D-Fe): isotherm and column experiments.

PubMed

Pantoja, M L; Jones, H; Garelick, H; Mohamedbakr, H G; Burkitbayev, M

2014-01-01

Iron hydroxide supported onto porous diatomite (D-Fe) is a low-cost material with potential to remove arsenic from contaminated water due to its affinity for the arsenate ion. This affinity was tested under varying conditions of pH, contact time, iron content in D-Fe and the presence of competitive ions, silicate and phosphate. Batch and column experiments were conducted to derive adsorption isotherms and breakthrough behaviours (50 μg L(-1)) for an initial concentration of 1,000 μg L(-1). Maximum capacity at pH 4 and 17% iron was 18.12-40.82 mg of arsenic/g of D-Fe and at pH 4 and 10% iron was 18.48-29.07 mg of arsenic/g of D-Fe. Adsorption decreased in the presence of phosphate and silicate ions. The difference in column adsorption behaviour between 10% and 17% iron was very pronounced, outweighing the impact of all other measured parameters. There was insufficient evidence of a correlation between iron content and arsenic content in isotherm experiments, suggesting that ion exchange is a negligible process occurring in arsenate adsorption using D-Fe nor is there co-precipitation of arsenate by rising iron content of the solute above saturation.

Response of acid mobilization of iron-containing mineral dust to improvement of air quality projected in the future

NASA Astrophysics Data System (ADS)

Ito, A.; Xu, L.

2014-04-01

Acidification of dust aerosols may increase aerosol iron (Fe) solubility, which is linked to mineral properties. Combustion aerosols can also elevate aerosol iron solubility when aerosol loading is low. Here, we use an atmospheric chemical transport model to investigate the deposition of filterable iron and its response to changes in anthropogenic emissions of both combustion aerosols and precursor gases. By introducing three classes of iron-containing minerals into the detailed aerosol chemistry model, we provide a theoretical examination of the effects of different dissolution behaviors on the acid mobilization of iron. Comparisons of modeled Fe dissolution curves with the measured dissolution rates for African, east Asian, and Australian dust samples show overall good agreement under acidic conditions. The improved treatment of Fe in mineral dust and its dissolution scheme results in reasonable predictive capability for iron solubility over the oceans in the Northern Hemisphere. Our model results suggest that the improvement of air quality projected in the future will lead to a decrease of the filterable iron deposition from iron-containing mineral dust to the eastern North Pacific due to less acidification in Asian dust, which is mainly associated with the reduction of nitrogen oxides (NOx) emissions. These results could have important implications for iron fertilization of phytoplankton growth, and highlight the necessity of improving the process-based quantitative understanding of the response of the chemical modification in iron-containing minerals to environmental changes.

Low-grade inflammation is associated with lower haemoglobin levels in healthy individuals: results from the Danish blood donor study.

PubMed

Kotzé, S R; Pedersen, O B; Petersen, M S; Sørensen, E; Thørner, L W; Sørensen, C J; Rigas, A S; Hjalgrim, H; Rostgaard, K; Ullum, H; Erikstrup, C

2016-08-01

Chronic inflammation can lead to anaemia of chronic disease due to the sequestration of iron caused by inflammatory cytokines and the protein hepcidin. However, the effect of low-grade inflammation (LGI) on haemoglobin among healthy individuals is not known. This study examines the effect of LGI on haemoglobin among Danish blood donors. We performed multivariable linear regression to assess the effect of LGI (i.e. high-sensitivity C-reactive protein above 3 mg/l but below 10 mg/l) on haemoglobin in 17 322 Danish blood donors. We also performed multivariable logistic regression to evaluate the effect of LGI on the risk of having low haemoglobin (below the 10th percentile among men and women, respectively). We adjusted for donation activity, age, sex, low ferritin, oral contraceptives and menopause. All analyses were stratified by current smoking status. LGI was associated with lower haemoglobin (0·08 mm lower [0·12 g/dl], 95% confidence interval (CI): -0·11-0·05) and increased risk of low haemoglobin (OR = 1·22, 95% CI: 1·05-1·43) in non-smokers. Conversely, LGI was associated with higher haemoglobin in smokers (0·12 mm [0·19 g/dl], 95% CI: 0·06-0·18). In this first study of LGI and haemoglobin in healthy individuals, there was a negative association between LGI and haemoglobin in non-smokers. The association was positive in smokers, probably because smoking leads to both increased inflammation and increased haemoglobin through CO exposure. © 2016 International Society of Blood Transfusion.

Iron deficiency anaemia: with the conclusion of a need for iron reader

NASA Astrophysics Data System (ADS)

Lim, Wai Feng; Yap, Boon Kar; Lai, Mei I.; Talik, Noorazrina; Nasser, Ammar Ahmed; Al-Haiqi, Ahmed Mubarak Ahmed; Sankar Krishnan, Prajindra

2017-10-01

In our bloodstream, there are plenty of red blood cells (RBC), which function as an important oxygen carrier in our bodies. Each RBC consists of millions of haemoglobin (Hb), which is made up from globin and iron. If any deficiency/malfunction of any globin, it will lead to anaemia as indicated in low Hb level while iron deficiency anaemia (IDA) is anaemic due to the lacking of iron as indicated in low Hb and ferritin levels. IDA affects almost two billion people globally while anaemia without iron deficiency, such as thalassaemia, affects almost 4.5% in Malaysian population. These anaemic conditions have similar clinical symptoms like fatigue, dizziness, in which disturb their cognitive development and productivity in workplace. In areas without proper medical access, many anaemic individuals were misdiagnosed and treated with iron tablets because they were thought to have iron deficiency anaemia due to low Hb content. But, excess iron is toxic to the body. Misdiagnosis can be avoided by iron status assessment. We hereby review the currently available iron status parameters in laboratory and field study with the conclusion of demonstrating the importance of a need for iron reader, in the effort to reduce the prevalence of IDA globally.

Iron status and anaemia in Sri Lankan secondary school children: A cross-sectional survey

PubMed Central

Allen, Stephen; Rodrigo, Rexan; Perera, Lakshman; Shao, Wei; Li, Chao; Wang, Duolao; Olivieri, Nancy; Weatherall, David J.; Premawardhena, Anuja

2017-01-01

Background Iron deficiency, the most common micronutrient disorder and cause of anaemia globally, impairs growth, cognition, behaviour and resistance to infection. Methods/Results As part of a national survey of inherited haemoglobin variants in 7526 students from 72 secondary schools purposefully selected from the 25 districts of Sri Lanka, we studied 5912 students with a normal haemoglobin genotype. Median age was 16.0 (IQR 15.0–17.0) years and 3189 (53.9%) students were males. Most students were Sinhalese (65.7%), with fewer Tamils (23.1%) and Muslims (11.2%). Anaemia occurred in 470 students and was more common in females (11.1%) than males (5.6%). Haemoglobin, serum ferritin, transferrin receptor and iron were determined in 1196 students with low red cell indices and a structured sample of those with normal red cell indices (n = 513). The findings were weighted to estimate the frequencies of iron deficiency and iron deficiency anaemia classified according to WHO criteria. Iron depletion (serum ferritin <15ug/ml) occurred in 19.2% and cellular iron deficiency (low serum ferritin and transferrin receptor >28.1 nmol/l) in 11.6% students. Iron deficiency anaemia (cellular iron deficiency with low haemoglobin) occurred in only 130/2794 (4.6%) females and 28/2789 (1.0%) males. Iron biomarkers were normal in 83/470 (14.6%) students with anaemia. In multiple regression analysis, the odds for iron depletion and cellular iron deficiency were about one-third in males compared with females, and the odds for iron deficiency anaemia were about one fifth in males compared to females. Tamil ethnicity and age <16 years increased the risk of all three stages of iron deficiency and living at high altitude significantly reduced the risk of iron depletion. Conclusions Low iron status and anaemia remain common problems in Sri Lankan secondary school students especially females, younger students and the socioeconomically disadvantaged Tamil population. More research is needed to identify factors other than low iron status that contribute to anaemia in adolescents. PMID:29155855

Metamorphic mineral assemblages of slightly calcic pelitic rocks in and around the Taconic Allochthon, southwestern Massachusetts and adjacent Connecticut and New York

USGS Publications Warehouse

Zen, E-an

1981-01-01

The mineral assemblages from metamorphosed slightly calcic pelitic rocks of the Taconic Range in southwestern Massachusetts and adjacent areas of Connecticut and New York were studied petrographically and chemically. These rocks vary in metamorphic grade from those below the chloritoid zone through the chloritoid and garnet zones into the kyanite-staurolite zone. Microprobe data on the ferromagnesian minerals show that the sequence of increasing Fe/ (Fe+Mg) value is, from the lowest, chlorite, biotite, hornblende, chloritoid, staurolite, garnet. Hornblende, epidote, garnet, and plagioclase are the most common minerals that carry significant calcium. Biotite is persistently deficient in alkali but is abnormally rich in octahedral aluminum to such an extent that the overall charge balance can be ascribed to an AI=K+ (Fe,Mg) diadochy. Muscovite contains small though persistent amounts of iron and magnesium in octahedral positions but has a variable K/Na ratio, which is potentially useful as a geothermometer. One low-grade muscovite is highly phengitic, but the white micas in rocks from metamorphic grades higher than chloritoid zone do not contain significant phengite components. Chlorite is persistently high in aluminum and so its ratio of divalent ions to aluminum is approximately that of garnet. Many garnets show pronounced zoning in manganese and less pronounced zoning in calcium. Garnet coexisting with hornblende contains a high proportion of the grossularitic component. The calcium content is significant in all the analyzed garnets, except those from a cummingtonite-bearing sample that is free of muscovite. This suggests that in slightly calcic pelitic rocks, calcium-free garnet cannot coexist with muscovite. Most of the mineral assemblages formed in the presence of excess quartz and muscovite. The phase-petrologic analysis, made with the aid of an eight-phase multisystematic model, shows the following major points: 1. Chloritoid and staurolite coexist in a definite interval of prograde metamorphism. 2. Biotite-chloritoid does not constitute an alternative assemblage to garnet-chlorite-muscovite, because the former combination is found predominantly in the presence of the latter combination. Because the garnet contains lime, all five phases are stable together in lowlime pelitic rocks. 3. The first appearance of staurolite in the area does not correspond to the reaction leading to the first intrinsic stable existence of this phase. Inasmuch as the first appearanc,e of staurolite is always in chlorite-bearing as semblages, I suggest that the mapped staurolite zone marker corresponds to a reaction whereby staurolitechlorite becomes stable. The probable lower grade chemical equivalent, for example, chloritoid-aluminum silicate, however, has not been found in the area of study. Several staurolite-forming reactions discussed in the literature are ruled out because of the relative siderophility of the minerals. A second staurolite isograd involves the reaction, chloritoid+chlorite+muscovite= staurolite+biotite. A third isograd involves staurolite+ chlorite=biotite+kyanite; this reaction is postulated on the basis of the observed assemblage biotite-kyanitesta urolite-garnet-muscoviteplagioclase-quartzilmenite. 4. In low-grade rocks, epidote is stable considerably before the first appearance of chloritoid. The nature of the high-aluminum phase in low-grade rocks that leads to the formation of chloritoid remains obscure. The epidote is always rich in ferric iron (pistacite content of about 1/ 4 to 1/3). Garnet-bearing assemblages (with or without epidote) are formed next as metamorphic grade increases. The next more calcium-rich silicate is hornblende, and despite the meager data on assemblages that include hornblende, the first intrinsic appearance of this phase has probably been recorded. At highstaurolite grade, the most calcium-rich assemblage in pelitic rocks is hornblende-garnet-biotite-plagioclase (bytownit

The Mechanical Property of Batch Annealed High Strength Low Alloy Steel HC260LA

NASA Astrophysics Data System (ADS)

Yang, Xiaojiang; Xia, Mingsheng; Zhang, Hongbo; Han, Bin; Li, Guilan

Cold rolled high strength low alloy steel is widely applied in the automotive parts due to its excellent formability and weldability. In this paper, the steel grade HC260LA according to European Norm was developed with batch annealing process. With commercial C-Mn mild steel as a benchmark, three different groups of chemistry namely C-Mn-Si, C-Mn-Nb-Ti and C-Mn-Nb were compared in terms of yield-tensile strength (Y/T) ratio. Microstructure and mechanical properties were characterized as well. Based on industrial production results, chemistry and detailed process parameters for batch annealing were identified. In the end the optimal Y/T ratio was proposed for this steel grade under batch annealing process.

Arsenic Mobilization Influenced By Iron Reduction And Sulfidogenesis Under Dynamic Flow

NASA Astrophysics Data System (ADS)

Kocar, B. D.; Stewart, B. D.; Herbel, M.; Fendorf, S.

2004-12-01

Sulfidogenesis and iron reduction are ubiquitous processes that occur in a variety of anoxic subsurface and surface environments, which profoundly impact the cycling of arsenic. Of the iron (hydr)oxides, ferrihydrite possesses one of the highest capacities to retain arsenic, and is globally distributed within soils and sediments. Upon dissimilatory iron reduction, ferrihydrite may transform to lower surface area minerals, such as goethite and magnetite, which decreases arsenic retention, thus enhancing its transport. Here we examine how arsenic retained on ferrihydrite is mobilized under dynamic flow in the presence of Sulfurosprillum barnesii strain SES-3, a bacteria capable of reducing both As(V) and Fe(III). Ferrihydrite coated sands, loaded with 150 mg kg-1 As(V), were inoculated with S. barnesii, packed into a column and reacted with a synthetic groundwater solution. Within several days after initiation of flow, the concentration of arsenic in the column effluent increased dramatically coincident with the mineralogical transformation of ferrihydrite and As(V) reduction to As(III). Following the initial pulse of arsenic, effluent concentration then declined to less than 10 μ M. Thus, arsenic release into the aqueous phase is contingent upon the incongruent reduction of As(V) and Fe(III) as mediated by biological activity. Reaction of abiotically or biotically generated dissolved sulfide with iron (hydr)oxides may have a dramatic influence on the fate of arsenic within surface and subsurface environments. Accordingly, we examined the reaction of dissolved bisulfide and iron (hydr)oxide complexed with arsenic in both batch and column systems. Low ratios of sulfide to iron in batch reaction systems result in the formation of elemental sulfur and concomitant arsenic release from the iron (hydr)oxide surface. High sulfide to iron ratios, in contrast, appear to favor the formation of iron and arsenic sulfides. Our findings demonstrate that iron (hydr)oxides may quench reactions between sulfide and constituents sorbed to iron (hydr)oxide surfaces, forming elemental sulfur as opposed to sulfide-arsenic complexes. In addition, reductive transformation of iron (hydr)oxide by dissolved sulfide may release sorbed constituents. Hence, moderate to low concentrations of dissolved sulfide in association with iron (hydr)oxides may inhibit sequestration of important contaminants that are attenuated by Fe(III) and/or S(-II) bearing phases.

Chemical Composition and Oxidation State of Iron-Containing Aerosol Particles Over West Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Fan, S.; Yu, S.; Lai, B.; Gao, Y.

2017-12-01

Iron is a limiting micronutrient element critical for the marine ecosystem. In the extensive high-nutrient low-chlorophyll (HNLC) regions of the Southern Ocean, the activities of phytoplankton are partly controlled by iron (Fe) from different sources, including atmospheric deposition. Among important properties of atmospheric Fe are the elemental composition and Fe oxidation state of Fe-containing aerosol particles, as these properties affect aerosol Fe solubility. To explore these issues, aerosol samples were collected at Palmer Station in West Antarctic Peninsula. Samples were analyzed by submicron synchrotron-based X-ray fluorescence (XRF) and X-ray absorption near edge structure (XANES) spectroscopy for the Fe oxidation state and elemental composition of aerosol particles. The morphological information of aerosol particles was also observed by the high-resolution fluorescence microscopy, revealing possible sources and formation processes of iron-containing particles. More detailed results will be discussed in this presentation.

24 CFR 3280.611 - Vents and venting.

Code of Federal Regulations, 2010 CFR

2010-04-01

... be DWV grade nylon or acetal; (iii) Spring shall be stainless steel wire, type 302; (iv) Sealing disc...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed...

24 CFR 3280.611 - Vents and venting.

Code of Federal Regulations, 2011 CFR

2011-04-01

... be DWV grade nylon or acetal; (iii) Spring shall be stainless steel wire, type 302; (iv) Sealing disc...) Materials—(1) Pipe. Vent piping shall be standard weight steel, wrought iron, brass, copper tube DWV, listed...

Photochemistry of iron citrates initiated by UV-VIS light

NASA Astrophysics Data System (ADS)

Corral Arroyo, Pablo; Dou, Jing; Alpert, Peter; Krieger, Ulrich; Ammann, Markus

2017-04-01

Aerosol aging refers to the multitude of physical and chemical transformation atmospheric particles undergo, which play an important role in the impact of aerosols on climate, air quality and health. Aging processes may be started by chromophores, which act as photocatalysts that induce the oxidation of non-absorbing molecules [1]. Iron (Fe(III)) carboxylate complexes absorb light below about 500 nm, which is followed by ligand to metal charge transfer (LMCT) resulting in the reduction of iron to Fe(II) and oxidation of the carboxylate ligands, a process that represents an important sink of organic acids in the troposphere [2]. Our goal is to investigate how these photochemical processes contribute to the change of chemical and physical properties of the aerosol particles. To achieve this scope, we carry out coated wall flow tube experiments, exposing films with iron citrate to UV light, which will give information about the radical and LVOC production (connecting the CWFT to a Chemiluminescent Detector or PTR-TOF-MS respectively). From extracting and analyzing the films after irradiation with UV light, we obtain a profile of low-volatility products evolving from the photochemistry of iron citrates. By Scanning Transmission X-Ray Microspectroscopy (STXM) we analyze changes in the C K-edge and Fe L-edge in particles loaded with iron citrate upon exposure to light and follow their chemical and structural evolution upon photochemical oxidation in situ to investigate the degradation kinetics under varying environmental conditions. [1] George G., Ammann M., D'Anna B., Donaldson D. J., Nizkorodov S. A., Heterogeneous photochemistry in the Atmosphere, Chem. Rev., 2015, 115 (10), pp 4218-4258 [2] Weller, C., Horn, S., and Herrmann, H.: Photolysis of Fe(III) carboxylate complexes: Fe(II) quantum yields and reaction mechanisms, Photochemistry and Photobiology A: Chemistry, 268, 24-36, 2013.

Planktonic Marine Iron-Oxidizers Drive Iron(III) Mineralization Under Low Oxygen Conditions

NASA Astrophysics Data System (ADS)

Luther, G. W., III; Field, E.; Findlay, A.; MacDonald, D. J.; Chan, C. S. Y.; Kato, S.

2016-02-01

Observations of modern microbes have led to several hypotheses on how microbes precipitated the extensive banded iron formations in the geologic record, but we have yet to resolve the exact microbial contributions. An initial hypotheses was that cyanobacteria produced oxygen that oxidized iron(II) abiotically; however, in modern environments such as microbial mats, where Fe(II) and O2 coexist, we commonly find microaerophilic chemolithotrophic iron(II)-oxidizing bacteria producing Fe(III) oxyhydroxides. This suggests that such iron-oxidizers could have inhabited niches in ancient coastal oceans where Fe(II) and O2 coexisted, and therefore contributed to iron deposits, but there is currently little evidence for planktonic marine iron-oxidizers in modern analogs. Here, we demonstrate successful cultivation of planktonic microaerophilic iron-oxidizing Zetaproteobacteria from the Chesapeake Bay during seasonal stratification. Iron-oxidizers were associated with low oxygen concentrations and active iron redox cycling in the oxic-anoxic transition zone (<3 µM O2, <0.2 µM H2S). While cyanobacteria were also detected in this transition zone, oxygen concentrations were too low to support significant rates of abiotic iron oxidation. Instead, cyanobacteria may be providing oxygen for microaerophilic iron(II) oxidation through a symbiotic relationship that promotes oxygen consumption rather than build-up. Our results suggest that once oxygenic photosynthesis evolved, microaerophilic chemolithotrophic iron(II)-oxidizers were likely important drivers of iron(III) mineralization in ancient oceans.

Amorphous and Nanocomposite Materials for Energy-Efficient Electric Motors

NASA Astrophysics Data System (ADS)

Silveyra, Josefina M.; Xu, Patricia; Keylin, Vladimir; DeGeorge, Vincent; Leary, Alex; McHenry, Michael E.

2016-01-01

We explore amorphous soft-magnetic alloys as candidates for electric motor applications. The Co-rich system combines the benefits of low hysteretic and eddy-current losses while exhibiting negligible magnetostriction and robust mechanical properties. The amorphous precursors can be devitrified to form nanocomposite magnets. The superior characteristics of these materials offer the advantages of ease of handling in the manufacturing processing and low iron losses during motor operation. Co-rich amorphous ribbons were laser-cut to build a stator for a small demonstrator permanent-magnet machine. The motor was tested up to ~30,000 rpm. Finite-element analyses proved that the iron losses of the Co-rich amorphous stator were ~80% smaller than for a Si steel stator in the same motor, at 18,000 rpm (equivalent to an electric frequency of 2.1 kHz). These low-loss soft magnets have great potential for application in highly efficient high-speed electric machines, leading to size reduction as well as reduction or replacement of rare earths in permanent-magnet motors. More studies evaluating further processing techniques for amorphous and nanocomposite materials are needed.

A mathematical model describes the malignant transformation of low grade gliomas: Prognostic implications.

PubMed

Bogdańska, Magdalena U; Bodnar, Marek; Piotrowska, Monika J; Murek, Michael; Schucht, Philippe; Beck, Jürgen; Martínez-González, Alicia; Pérez-García, Víctor M

2017-01-01

Gliomas are the most frequent type of primary brain tumours. Low grade gliomas (LGGs, WHO grade II gliomas) may grow very slowly for the long periods of time, however they inevitably cause death due to the phenomenon known as the malignant transformation. This refers to the transition of LGGs to more aggressive forms of high grade gliomas (HGGs, WHO grade III and IV gliomas). In this paper we propose a mathematical model describing the spatio-temporal transition of LGGs into HGGs. Our modelling approach is based on two cellular populations with transitions between them being driven by the tumour microenvironment transformation occurring when the tumour cell density grows beyond a critical level. We show that the proposed model describes real patient data well. We discuss the relationship between patient prognosis and model parameters. We approximate tumour radius and velocity before malignant transformation as well as estimate the onset of this process.

Enhancing the Process of Anaerobic Ammonium Oxidation Coupled to Iron Reduction in Constructed Wetland Mesocosms with Supplementation of Ferric Iron Hydroxides

NASA Astrophysics Data System (ADS)

Shuai, W.; Jaffe, P. R.

2017-12-01

Effective ammonium (NH4+) removal has been a challenge in wastewater treatment processes. Aeration, which is required for the conventional NH4+ removal approach by ammonium oxidizing bacteria, is an energy intensive process during the operation of wastewater treatment plant. The efficiency of NH4+ oxidation in natural systems is also limited by oxygen transfer in water and sediments. The objective of this study is to enhance NH4+ removal by applying a novel microbial process, anaerobic NH4+ oxidation coupled to iron (Fe) reduction (also known as Feammox), in constructed wetlands (CW). Our studies have shown that an Acidimicrobiaceae bacterium named A6 can carry out the Feammox process using ferric Fe (Fe(III)) minerals like ferrihydrite as their electron acceptor. To investigate the properties of the Feammox process in CW as well as the influence of electrodes, Feammox bacterium A6 was inoculated in planted CW mesocosms with electrodes installed at multiple depths. CW mesocosms were operated using high NH4+ nutrient solution as inflow under high or low sediment Fe(III) level. During the operation, NH4+ and ferrous Fe concentration, pore water pH, voltages between electrodes, oxidation reduction potential and dissolved oxygen were measured. At the end of the experiment, CW sediment samples at different depths were taken, DNAs were extracted and quantitative polymerase chain reaction and pyrosequencing were performed to analyze the microbial communities. The results show that the high Fe level CW mesocosm has much higher NH4+ removal ability than the low Fe level CW mesocosm after Fe-reducing conditions are developed. This indicates the enhanced NH4+ removal can be attributed to elevated Feammox activity in high Fe level CW mesocosm. The microbial community structures are different in high or low Fe level CW mesocosms and on or away from the installed electrodes. The voltages between cathode and anode increased after the injection of A6 enrichment culture in low Fe level CW mesocosm but remained stable in high Fe level CW mesocosm, indicating A6 may use electrodes as their electron acceptor in the scarcity of Fe(III). The application of Feammox process in Fe-rich CW is promising in providing a cost and energy effective NH4+ removal approach, and the electrogenesis of A6 may also be useful in enhancing the Feammox process.

Low-pH cola beverages do not affect women's iron absorption from a vegetarian meal.

PubMed

Collings, Rachel; Fairweather-Tait, Susan J; Dainty, Jack R; Roe, Mark A

2011-05-01

Preliminary data in the literature indicate that iron absorption from a meal may be increased when consumed with low-pH beverages such as cola, and it is also possible that sugar iron complexes may alter iron availability. A randomized, crossover trial was conducted to compare the bioavailability of nonheme iron from a vegetarian pizza meal when consumed with 3 different beverages (cola, diet cola, and mineral water). Sixteen women with serum ferritin concentrations of 11-54 µg/L were recruited and completed the study. The pizza meal contained native iron and added ferric chloride solution as a stable isotope extrinsic label; the total iron content of the meal was ~5.3 mg. Incorporation of iron from the meal into RBC was not affected by the type of drink (9.9% with cola, 9.4% with diet cola, and 9.6% with water). Serum ferritin and plasma hepcidin were correlated (r = 0.66; P<0.001) and both were significant predictors of iron bioavailability, but their combined effect explained only 30% of the inter-individual variation (P<0.001) and illustrates the current lack of understanding of mechanisms responsible for the fine-tuning of iron absorption. Although there was no effect of low-pH drinks on iron bioavailability in healthy women, their effect on absorption of fortification iron that requires solubilization in dilute acid, such as reduced iron, and in individuals with low gastric acid production, such as older people and individuals with Helicobacter pylori infection, warrants further investigation.

Transfer and transformation of soil iron and implications for hydrogeomorpholocial changes in Naoli River catchment, sanjiang plain, Northeast China

USGS Publications Warehouse

Ming, J.; Xianguo, L.; Hongqing, W.; Yuanchun, Z.; Haitao, W.

2011-01-01

Wetland soils are characterized by alternating redox process due to the fluctuation of waterlogged conditions. Iron is an important redox substance, and its transfer and transformation in the wetland ecosystem could be an effective indicator for the environment changes. In this paper, we selected the Naoli River catchment in the Sanjiang Plain, Northeast China as the study area to analyze the dynamics of transfer and transformation of soil iron, and the relationship between iron content change and environmental factors. The results show that the total and crystalline iron contents reach the peak in the depth of 60 cm in soil profile, while the amorphous iron content is higher in the topsoil. In the upper reaches, from the low to high landscape positions, the total and crystalline iron contents decrease from 62.98 g/kg to 41.61 g/kg, 22.82 g/kg to 10.53 g/kg respectively, while the amorphous iron content increases from 2.42 g/kg to 8.88 g/kg. Amorphous iron content has positive correlation with organic matter and soil water contents, while negative correlation with pH. Moreover, both the crystalline and amorphous iron contents present no correlation with total iron content, indicating that environmental factors play a more important role in the transfer and transformation of iron other than the content of the total iron. Different redoximorphic features were found along the soil profile due to the transfer and transformation of iron. E and B horizons of wetland soil in the study area have a matrix Chroma 2 or less, and all the soil types can meet the criteria of American hydric soil indicators except albic soil. ?? Science Press, Science Press, Northeast Institute of Geography and Agroecology, CAS and Springer-Verlag Berlin Heidelberg 2011.

Commandant’s International Technical Series. Volume 7. Regulations and Guidelines for Inert Gas Systems

DTIC Science & Technology

1980-04-01

problems might arise that would not occur in the absence of the system. Such problems include generation of static charges and pyrophoric iron ...gas isolating valves should take into account the temperature ofogas at the offtake. Cast iron is acceptable for temperatures below C20 0. Valves... sulfide , *Each U.S.-flag tankship that is certified to carry Grades A, B, C, D, and some E liquids. i1 2 which can ignite spontaneously or emit sparks when

Effect of basicity and reductant amount in the nickel pig iron (NPI) production from Indonesian limonite ore in submerged electric arc furnace (SAF)

NASA Astrophysics Data System (ADS)

Astuti, W.; Andika, R.; Nurjaman, F.

2018-01-01

The effect of basicity and reductant amount on the nickel and iron recovery of the nickel pig iron (NPI) production from Indonesian limonite ore was investigated in the experimental study using submerged electric arc furnace (SAF). Indonesian limonite ore used in this study originated from Sulawesi Island with the composition of Ni (1.26%) and Fe (43%). Metallurgical coke was applied as the reductant. This study showed that the the highest nickel and iron recovery as well as metal yield can be resulted from the basicity of 0.8 and reductant amount of 0.23 kg coke/kg limonite ore. Nickel content in the NPI produced was around 3 - 4%. It was concluded that this experiment can produce medium grade NPI.

Low molecular weight carboxylic acids in oxidizing porphyry copper tailings.

PubMed

Dold, Bernhard; Blowes, David W; Dickhout, Ralph; Spangenberg, Jorge E; Pfeifer, Hans-Rudolf

2005-04-15

The distribution of low molecular weight carboxylic acids (LMWCA) was investigated in pore water profiles from two porphyry copper tailings impoundments in Chile (Piuquenes at La Andina and Cauquenes at El Teniente mine). The objectives of this study were (1) to determine the distribution of LMWCA, which are interpreted to be the metabolic byproducts of the autotroph microbial community in this low organic carbon system, and (2) to infer the potential role of these acids in cycling of Fe and other elements in the tailings impoundments. The speciation and mobility of iron, and potential for the release of H+ via hydrolysis of the ferric iron, are key factors in the formation of acid mine drainage in sulfidic mine wastes. In the low-pH oxidation zone of the Piuquenes tailings, Fe(III) is the dominant iron species and shows high mobility. LMWCA, which occur mainly between the oxidation front down to 300 cm below the tailings surface at both locations (e.g., max concentrations of 0.12 mmol/L formate, 0.17 mmol/L acetate, and 0.01 mmol/L pyruvate at Piuquenes and 0.14 mmol/L formate, 0.14 mmol/L acetate, and 0.006 mmol/L pyruvate at Cauquenes), are observed at the same location as high Fe concentrations (up to 71.2 mmol/L Fe(II) and 16.1 mmol/L Fe(III), respectively). In this zone, secondary Fe(III) hydroxides are depleted. Our data suggest that LMWCA may influence the mobility of iron in two ways. First, complexation of Fe(III), through formation of bidentate Fe(III)-LMWCA complexes (e.g., pyruvate, oxalate), may enhance the dissolution of Fe(III) (oxy)hydroxides or may prevent precipitation of Fe(III) (oxy)hydroxides. Soluble Fe(III) chelate complexes which may be mobilized downward and convert to Fe(II) by Fe(III) reducing bacteria. Second, monodentate LMWCA (e.g., acetate and formate) can be used by iron-reducing bacteria as electron donors (e.g., Acidophilum spp.), with ferric iron as the electron acceptor. These processes may, in part, explain the low abundances of secondary Fe(III) hydroxide precipitates below the oxidation front and the high concentrations of Fe(II) observed in the pore waters of some low-sulfide systems. The reduction of Fe(III) and the subsequent increase of iron mobility and potential acidity transfer (Fe(II) oxidation can result in the release of H+ in an oxic environment) should be taken in account in mine waste management strategies.

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

Nabeel, A.; Khan, T.A.; Sharma, D.K.

The use of low-grade coal in thermal power stations is leading to environmental pollution due to the generation of large amounts of fly ash, bottom ash, and CO{sub 2} besides other pollutants. It is therefore important to clean the coal before using it in thermal power stations, steel plants, or cement industries etc. Physical beneficiation of coal results in only limited cleaning of coal. The increasing environmental pollution problems from the use of coal have led to the development of clean coal technologies. In fact, the clean use of coal requires the cleaning of coal to ultra low ash contents,more » keeping environmental norms and problems in view and the ever-growing need to increase the efficiency of coal-based power generation. Therefore this requires the adaptation of chemical cleaning techniques for cleaning the coal to obtain ultra clean coal having ultra low ash contents. Presently the reaction conditions for chemical demineralization of low-grade coal using 20% aq NaOH treatment followed by 10% H{sub 2}SO{sub 4} leaching under reflux conditions have been optimized. In order to reduce the concentration of alkali and acid used in this process of chemical demineralization of low-grade coals, stepwise, i.e., three step process of chemical demineralization of coal using 1% or 5% aq NaOH treatment followed by 1% or 5% H{sub 2}SO{sub 4} leaching has been developed, which has shown good results in demineralization of low-grade coals. In order to conserve energy, the alkali-acid leaching of coal was also carried out at room temperature, which gave good results.« less

Accumulation of Contaminants in the Distribution System.

EPA Science Inventory

Removal of arsenic from water using iron-related processes including coagulation with iron salts, iron removal with oxidation/filtration, and specific iron resins is established. These processes are effective because iron solids including minerals and chemical floc have strong ad...

Identification of an exposure risk to heavy metals from pharmaceutical-grade rubber stoppers.

PubMed

Li, Xianghui; Qian, Pingping

2017-07-01

Exposure to low concentrations of heavy metals and metalloids represents a well-documented risk to animal and human health. However, current standards (European Pharmacopeia [EP], United States Pharmacopoeia [USP], International Organization for Standardization [ISO], YBB concerned with rubber closures) only require testing for Zn in pharmaceutical-grade rubber stoppers and then using only pure water as a solvent. We extracted and quantified heavy metals and trace elements from pharmaceutical-grade rubber stoppers under conditions that might occur during the preparation of drugs. Pure water, saline, 10% glucose, 3% acetic acid (w/v), 0.1 mol/L hydrochloric acid, and diethylenetriaminepentaacetic acid (4 mg/mL, 0.4 mg/mL, and 0.04 mg/mL) were used as extraction agents. We quantified the extracted arsenic, lead, antimony, iron, magnesium, aluminum, and zinc using inductively coupled plasma mass spectrometry. The concentration of extracted metals varied depending on the different extraction solutions used and between the different rubber stopper manufacturers. Rubber stoppers are ubiquitously used in the pharmaceutical industry for the storage and preparation of drugs. Extraction of heavy metals during the manufacturing and preparation of drugs represents a significant risk, suggesting a need for industry standards to focus on heavy metal migration from rubber stoppers. Copyright © 2016. Published by Elsevier B.V.

46 CFR 56.60-10 - Cast iron and malleable iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Cast iron and malleable iron. 56.60-10 Section 56.60-10... APPURTENANCES Materials § 56.60-10 Cast iron and malleable iron. (a) The low ductility of cast iron and... avoided. Cast iron and malleable iron components shall not be used at temperatures above 450 °F. Cast iron...

Investigation of the plastic fracture of high strength steels

NASA Technical Reports Server (NTRS)

Cox, T. B.; Low, J. R., Jr.

1972-01-01

An investigation of the plastic fracture process to improve tensile strength in high strength steels is presented. Two generic types of steels are considered: a quenched and tempered grade and a maraging grade, in order to compare two different matrix microstructures. Each type of steel was studied in commercial grade purity and in special melted high purity form, low in residual and impurity elements. The specific alloys dealt with include AISI 4340 and 18 Ni, 200 grade maraging steel, both heat treated to the same yield strength level of approximately 200 ksi.

Automated Processing of Dynamic Contrast-Enhanced MRI: Correlation of Advanced Pharmacokinetic Metrics with Tumor Grade in Pediatric Brain Tumors.

PubMed

Vajapeyam, S; Stamoulis, C; Ricci, K; Kieran, M; Poussaint, T Young

2017-01-01

Pharmacokinetic parameters from dynamic contrast-enhanced MR imaging have proved useful for differentiating brain tumor grades in adults. In this study, we retrospectively reviewed dynamic contrast-enhanced perfusion data from children with newly diagnosed brain tumors and analyzed the pharmacokinetic parameters correlating with tumor grade. Dynamic contrast-enhanced MR imaging data from 38 patients were analyzed by using commercially available software. Subjects were categorized into 2 groups based on pathologic analyses consisting of low-grade (World Health Organization I and II) and high-grade (World Health Organization III and IV) tumors. Pharmacokinetic parameters were compared between the 2 groups by using linear regression models. For parameters that were statistically distinct between the 2 groups, sensitivity and specificity were also estimated. Eighteen tumors were classified as low-grade, and 20, as high-grade. Transfer constant from the blood plasma into the extracellular extravascular space (K trans ), rate constant from extracellular extravascular space back into blood plasma (K ep ), and extracellular extravascular volume fraction (V e ) were all significantly correlated with tumor grade; high-grade tumors showed higher K trans , higher K ep , and lower V e . Although all 3 parameters had high specificity (range, 82%-100%), K ep had the highest specificity for both grades. Optimal sensitivity was achieved for V e , with a combined sensitivity of 76% (compared with 71% for K trans and K ep ). Pharmacokinetic parameters derived from dynamic contrast-enhanced MR imaging can effectively discriminate low- and high-grade pediatric brain tumors. © 2017 by American Journal of Neuroradiology.

Iron metabolism in critically ill patients developing anemia of inflammation: a case control study.

PubMed

Boshuizen, Margit; Binnekade, Jan M; Nota, Benjamin; van de Groep, Kirsten; Cremer, Olaf L; Tuinman, Pieter R; Horn, Janneke; Schultz, Marcus J; van Bruggen, Robin; Juffermans, Nicole P

2018-05-02

Anemia occurring as a result of inflammatory processes (anemia of inflammation, AI) has a high prevalence in critically ill patients. Knowledge on changes in iron metabolism during the course of AI is limited, hampering the development of strategies to counteract AI. This case control study aimed to investigate iron metabolism during the development of AI in critically ill patients. Iron metabolism in 30 patients who developed AI during ICU stay was compared with 30 septic patients with a high Hb and 30 non-septic patients with a high Hb. Patients were matched on age and sex. Longitudinally collected plasma samples were analyzed for levels of parameters of iron metabolism. A linear mixed model was used to assess the predictive values of the parameters. In patients with AI, levels of iron, transferrin and transferrin saturation showed an early decrease compared to controls with a high Hb, already prior to the development of anemia. Ferritin, hepcidin and IL-6 levels were increased in AI compared to controls. During AI development, erythroferrone decreased. Differences in iron metabolism between groups were not influenced by APACHE IV score. The results show that in critically ill patients with AI, iron metabolism is already altered prior to the development of anemia. Levels of iron regulators in AI differ from septic controls with a high Hb, irrespective of disease severity. AI is characterized by high levels of hepcidin, ferritin and IL-6 and low levels of iron, transferrin and erythroferrone.

[Biological diagnosis of iron deficiency in children].

PubMed

Thuret, I

2017-05-01

Measurement of serum ferritin (SF) is currently the laboratory test recommended for diagnosing iron deficiency. In the absence of an associated disease, a low SF value is an early and highly specific indicator of iron deficiency. The WHO criteria proposed to define depleted storage iron are 12μg/L for children under 5 years and 15μg/L for those over 5 years. A higher threshold of 30μg/L is used in the presence of infection or inflammation. Iron deficiency anemia, with typical low mean corpuscular volume and mean corpuscular hemoglobin, is only present at the end stage of iron deficiency. Other diagnostic tests for iron deficiency including iron parameters (low serum iron, increased total iron-binding capacity, low transferrin saturation) and erythrocyte traits (low mean corpuscular volume, increased zinc protoporphyrin) provide little additional diagnostic value over SF. In children, serum soluble transferrin receptor (sTfR) has been reported to be a sensitive indicator of iron deficiency and is relatively unaffected by inflammation. On the other hand, sTfR is directly related to extent of erythroid activity and not commonly used in clinical practice. In population surveys, approaches based on combinations of markers have been explored to improve the specificity and sensitivity of diagnostic. In addition to Hb value determination, a combination of parameters (among transferrin saturation, zinc protoporphyrin, mean corpuscular volume or serum ferritin) was generally used to assess iron deficiency. More recently sTfR/ ferritin index were evaluated, sTfR in conjunction with SF allowing to better distinguishing iron deficiency from inflammatory anemia. Also, hepcidin measurements appeared an interesting marker for diagnosing iron deficiency and identifying individuals in need of iron supplementation in populations where inflammatory or infectious diseases are frequently encountered. Reticulocyte Hb content (CHr) determination is an early parameter of iron deficiency erythropoiesis. CHr can be measured with several automated hematology analyzers and so, used for individual's iron status assessment. In addition to Hb concentration determination, individual's iron status is commonly assessed in the pediatric clinical practice by the SF measurement accompanied by the determination of C-reactive protein for detection of a simultaneous acute infection and/or inflammation. © 2017 Elsevier Masson SAS. Tous droits réservés.

Cryogenic filter method produces super-pure helium and helium isotopes

NASA Technical Reports Server (NTRS)

Hildebrandt, A. F.

1964-01-01

Helium is purified when cooled in a low pressure environment until it becomes superfluid. The liquid helium is then filtered through iron oxide particles. Heating, cooling and filtering processes continue until the purified liquid helium is heated to a gas.

Processing of converter sludges on the basis of thermal-oxidative coking with coals

NASA Astrophysics Data System (ADS)

Kuznetsov, S. N.; Shkoller, M. B.; Protopopov, E. V.; Kazimirov, S. A.; Temlyantsev, M. V.

2017-09-01

The paper deals with the solution of an important problem related to the recycling of converter sludge. High moisture and fine fractional composition of waste causes the application of their deep dehydration and lumping. To reduce environmental emissions the non-thermal method of dehydration is considered - adsorption-contact drying. As a sorbent, the pyrolysis product of coals from the Kansko-Achinsky basin - brown coal semi-coke (BSC) obtained by the technology “Thermokoks”. Experimental data on the dehydration of high-moisture wastes with the help of BSC showed high efficiency of the selected material. The lumping of the dried converter dust was carried out by thermo-chemical coking with coals of grades GZh (gas fat coal) and Zh (fat coal). As a result, an iron-containing product was obtained - ferrocoke, which is characterized by almost complete reduction of iron oxides, as well as zinc transition into a vapor state, and is removed with gaseous process products. Based on the results of the experimental data a process basic diagram of the utilization of converter sludge to produce ferrocoke was, which can be effectively used in various metallurgical aggregates, for example, blast furnaces, converters and electric arc furnaces. In the basic technological scheme heat generated by ferrocoke cooling and the energy of the combustion products after the separation of zinc in the gas turbine plant will be used.

Low-cost Solar Array Project. Feasibility of the Silane Process for Producing Semiconductor-grade Silicon

NASA Technical Reports Server (NTRS)

1979-01-01

The feasibility of Union Carbide's silane process for commercial application was established. An integrated process design for an experimental process system development unit and a commercial facility were developed. The corresponding commercial plant economic performance was then estimated.

Synthesis of potassium ferrate using residual ferrous sulfate as iron bearing material

NASA Astrophysics Data System (ADS)

Kanari, N.; Filippov, L.; Diot, F.; Mochón, J.; Ruiz-Bustinza, I.; Allain, E.; Yvon, J.

2013-03-01

This paper summarizes the results obtained during potassium ferrate (K2FeVIO4) synthesis which is a high added value material. This compound that contains iron in the rare hexavalent state is becoming a substance of growing importance for the water and effluent treatment industries. This is due to its multi-functional nature (oxidation, flocculation, elimination of heavy metals, decomposition of organic matter, etc.). The most well known synthesis methods for potassium ferrate synthesis are those involving the chemical and/or electrochemical oxidation of iron (II) and (III) from aqueous solutions having a high alkali concentration. These methods are generally characterized by a low FeVI efficiency due to the reaction of the potassium ferrate with water, leading to the reduction of FeVI into FeIII. Concerning the work pertinent to this paper, the synthesis of K2FeVIO4 was achieved by a simultaneous reaction of two solids (iron sulfate and KOH) and one gaseous oxidant (chlorine). The synthesis process is performed in a rotary reactor at room temperature and the global synthesis reaction is exothermic. The effects of different experimental parameters on the potassium ferrate synthesis are investigated to determine the optimal conditions for the process.

Effect of ferrous sulfate fortification in germinated brown rice on seed iron concentration and bioavailability.

PubMed

Wei, Yanyan; Shohag, M J I; Ying, Feng; Yang, Xiaoe; Wu, Chunyong; Wang, Yuyan

2013-06-01

The present study evaluated the effectiveness of germination and iron fortification on iron concentration and bioavailability of brown rice. Iron fortification during germination process with 0.05-2 g/L ferrous sulfate increased the iron concentration in germinated brown rice from 1.1 to 15.6 times than those in raw brown rice. Based on the recommended dietary allowance of iron, maximum germination rate and γ-aminobutyric acid, we recommend the brown rice fortified with 0.25 g/L FeSO(4) as a suitable fortification level to use in germination process. Iron fortification during the germination process has a positive effect on iron concentration and bioavailability. A significant difference was observed among the cultivars in respect to the capacity for iron accumulation and bioavailability. Germination alone could improve in vitro iron solubility, but had no effect on iron bioavailability in Caco-2 cell, the additional fortification process should be combined to get high amount of bioavailable iron from the brown rice. Copyright © 2012 Elsevier Ltd. All rights reserved.

Platinum isotopes in iron meteorites: Galactic cosmic ray effects and nucleosynthetic homogeneity in the p-process isotope 190Pt and the other platinum isotopes

NASA Astrophysics Data System (ADS)

Hunt, Alison C.; Ek, Mattias; Schönbächler, Maria

2017-11-01

Platinum isotopes are sensitive to the effects of galactic cosmic rays (GCR), which can alter isotope ratios and mask nucleosynthetic isotope variations. Platinum also features one p-process isotope, 190Pt, which is very low abundance and therefore challenging to analyse. Platinum-190 is relevant for early solar-system chronology because of its decay to 186Os. Here, we present new Pt isotope data for five iron meteorite groups (IAB, IIAB, IID, IIIAB and IVA), including high-precision measurements of 190Pt for the IAB, IIAB and IIIAB irons, determined by multi-collector ICPMS. New data are in good agreement with previous studies and display correlations between different Pt isotopes. The slopes of these correlations are well-reproduced by the available GCR models. We report Pt isotope ratios for the IID meteorite Carbo that are consistently higher than the predicted effects from the GCR model. This suggests that the model predictions do not fully account for all the GCR effects on Pt isotopes, but also that the pre-atmospheric radii and exposure times calculated for Carbo may be incorrect. Despite this, the good agreement of relative effects in Pt isotopes with the predicted GCR trends confirms that Pt isotopes are a useful in-situ neutron dosimeter. Once GCR effects are accounted for, our new dataset reveals s- and r-process homogeneity between the iron meteorite groups studied here and the Earth. New 190Pt data for the IAB, IIAB and IIIAB iron meteorites indicate the absence of GCR effects and homogeneity in the p-process isotope between these groups and the Earth. This corresponds well with results from other heavy p-process isotopes and suggests their homogenous distribution in the inner solar system, although it does not exclude that potential p-process isotope variations are too diluted to be currently detectable.

Silica and Pyroxene in IVA Irons; Possible Formation of the IVA Magma by Impact Melting and Reduction of L-LL-Chondrite Materials Followed by Crystallization and Cooling

NASA Technical Reports Server (NTRS)

Wasson, John T.; Matsunami, Yoshiyuki; Rubin, Alan E.

2006-01-01

Group IVA is a large magmatic group of iron meteorites. The mean DELTA O-17 (= delta O-17 - 0.52(raised dot) delta O-18) of the silicates is approx. plus or minus 1.2%o, similar to the highest values in L chondrites and the lowest values in LL chondrites; delta O-18 values are also in the L/LL range. This strongly suggests that IVA irons formed by melting L-LL parental material, but the mean Ni content of IVA irons (83 mg/g) is much lower than that of a presumed L-LL parent (approx. 170 mg/g) and the low-Ca pyroxene present in two IVA meteorites is Fs13, much lower than the Fs20-29 values in L and LL chondrites. Thus, formation from L-LL precursors requires extensive addition of metallic Fe, probably produced by reduction of FeS and FeO. Group IVA also has S/Ni, Ga/Ni, and Ge/Ni ratios that are much lower than those in L-LL chondrites or any chondrite group that preserves nebular compositions, implying loss of these volatile elements during asteroidal processing. We suggest that these reduction and loss processes occurred near the surface of the asteroid during impact heating, and resulted partly from reduction by C, and partly from the thermal dissociation of FeS and FeO with loss of O and S. The hot (approx. 1770 K) low-viscosity melt quickly moved through channels in the porous asteroid to form a core. Two members of the IVA group, Sao Joao Nepomuceno (hereafter, SJN) and Steinbach, contain moderate amounts of orthopyroxene and silica, and minor amounts of low-Ca clinopyroxene. Even though SJN formed after approx. 26% crystallization and Steinbach formed after approx. 77% Crystallization of the IVA core, both could have originated within several tens of meters of the core-mantle interface if 99% of the crystallization occurred from the center outwards. Two other members of the group (Gibeon and Bishop Canyon) contain tabular tridymite, which we infer to have initially formed as veins deposited from a cooling SiO-rich vapor. The silicates were clearly introduced into IVA irons after the initial magma crystallized. Because the y-iron crystals in SJN are typically about 5 cm across, an order of magnitude smaller than in IVA irons that do not contain massive silicates, we infer that the metal was in the gamma-iron field when the silicates were injected. The SJN and Steinbach silicate compositions are near the low-Ca-pyroxene/silica eutectic compositions. We suggest that a tectonic event produced a eutectic-like liquid and injected it together with unmelted pyroxene grains into fissures in the solid metal core. Published estimates of IVA metallographic cooling rates range from 20 to 3000 K/Ma, leading to a hypothesized breakup of the core during a major impact followed by scrambling of the core and mantle debris [Haack, H., Scott, E.R.D., Love, S.G., Brearley, A. 1996. Thermal histories of IVA stony-iron and iron meteorites: evidence for asteroid fragmentation and reaccretion. Geochim. Cosmochim. Acta 60, 3103-3113]. This scrambling model is physically implausible and cannot explain the strong correlation of estimated cooling rates with metal composition. Previous workers concluded that the low-Ca clinopyroxene in SJN and Steinbach formed from protopyroxene by quenching at a cooling rate of 10(sup 12) K/Ma, and suggested that this also supported an impact-scrambling model. This implausible spike in cooling rate by a factor of 10(sup 10) can be avoided if the low-Ca clinopyroxene were formed by a late shock event that converted orthopyroxene to clinopyroxene followed by minimal growth in the clinopyroxene field, probably because melt was also produced. We suggest that metallographic cooling-rate estimates (e.g., based on island taenite) giving similar values throughout the metal compositional range are more plausible, and that the IVA parent asteroid can be modeled by monotonic cooling followed by a high-temperature impact event that introduced silicates into the metal and a low-temperature impact event that partially converted thopyroxene into low-Ca clinopyroxene.

Model of reticuloendothelial iron metabolism in humans: Abnormal behavior in idiopathic hemochromatosis and in inflammation

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

Fillet, G.; Beguin, Y.; Baldelli, L.

1989-08-01

Iron transport in the reticuloendothelial (RE) system plays a central role in iron metabolism, but its regulation has not been characterized physiologically in vivo in humans. In particular, why serum iron is elevated and RE cells are much less iron-loaded than parenchymal cells in idiopathic hemochromatosis is not known. The processing of erythrocyte iron by the RE system was studied after intravenous (IV) injection of 59Fe heat-damaged RBCs (HDRBCs) and 55Fe transferrin in normal subjects and in patients with iron deficiency, idiopathic hemochromatosis, inflammation, marrow aplasia, or hyperplastic erythropoiesis. Early release of 59Fe by the RE system was calculated frommore » the plasma iron turnover and the 59Fe plasma reappearance curve. Late release was calculated from the ratio of 59Fe/55Fe RBC utilization in 2 weeks. The partitioning of iron between the early (release from heme catabolism) and late (release from RE stores) phases depended on the size of RE iron stores, as illustrated by the inverse relationship observed between early release and plasma ferritin (P less than .001). There was a strong correlation between early release and the rate of change of serum iron levels during the first three hours in normal subjects (r = .85, P less than .001). Inflammation produced a blockade of the early release phase, whereas in idiopathic hemochromatosis early release was considerably increased as compared with subjects with similar iron stores. Based on these results, we describe a model of RE iron metabolism in humans. We conclude that the RE system appears to determine the diurnal fluctuations in serum iron levels through variations in the immediate output of heme iron. In idiopathic hemochromatosis, a defect of the RE cell in withholding iron freed from hemoglobin could be responsible for the high serum iron levels and low RE iron stores.« less

Compositional variability of nutrients and phytochemicals in corn after processing.

PubMed

Prasanthi, P S; Naveena, N; Vishnuvardhana Rao, M; Bhaskarachary, K

2017-04-01

The result of various process strategies on the nutrient and phytochemical composition of corn samples were studied. Fresh and cooked baby corn, sweet corn, dent corn and industrially processed and cooked popcorn, corn grits, corn flour and corn flakes were analysed for the determination of proximate, minerals, xanthophylls and phenolic acids content. This study revealed that the proximate composition of popcorn is high compared to the other corn products analyzed while the mineral composition of these maize products showed higher concentration of magnesium, phosphorus, potassium and low concentration of calcium, manganese, zinc, iron, copper, and sodium. Popcorn was high in iron, zinc, copper, manganese, sodium, magnesium and phosphorus. The xanthophylls lutein and zeaxanthin were predominant in the dent corn and the total polyphenolic content was highest in dent corn while the phenolic acids distribution was variable in different corn products. This study showed preparation and processing brought significant reduction of xanthophylls and polyphenols.

Cognitive Processing and Mathematical Achievement: A Study with Schoolchildren between Fourth and Sixth Grade of Primary Education

ERIC Educational Resources Information Center

Iglesias-Sarmiento, Valentin; Deano, Manuel

2011-01-01

This investigation analyzed the relation between cognitive functioning and mathematical achievement in 114 students in fourth, fifth, and sixth grades. Differences in cognitive performance were studied concurrently in three selected achievement groups: mathematical learning disability group (MLD), low achieving group (LA), and typically achieving…

How Fifth-Grade Students Use Story Mapping to Aid Their Reading Comprehension

ERIC Educational Resources Information Center

Weih, Timothy G.

2000-01-01

This thesis examined the reading comprehension process of three fifth-grade students who demonstrated the ability to read and write fluently but had difficulties remembering and understanding important information about what they read. The aim of this research was to develop and implement an effective teaching strategy for low-achieving students…

Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

NASA Astrophysics Data System (ADS)

Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

2016-02-01

This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

Iron

MedlinePlus

... too little iron, you may develop iron deficiency anemia. Causes of low iron levels include blood loss, poor diet, or an inability to absorb enough iron from foods. People at higher risk of having too little iron are young children and women who are pregnant or have periods. ...

Wear resistance of ductile irons

NASA Astrophysics Data System (ADS)

Lerner, Y. S.

1994-06-01

This study was undertaken to evaluate the wear resistance of different grades of ductile iron as alterna-tives to high- tensile- strength alloyed and inoculated gray irons and bronzes for machine- tool and high-pressure hydraulic components. Special test methods were employed to simulate typical conditions of reciprocating sliding wear with and without abrasive- contaminated lubricant for machine and press guideways. Quantitative relationships were established among wear rate, microstructure and micro-hardness of structural constituents, and nodule size of ductile iron. The frictional wear resistance of duc-tile iron as a bearing material was tested with hardened steel shafts using standard test techniques under continuous rotating movement with lubricant. Lubricated sliding wear tests on specimens and compo-nents for hydraulic equipment and apparatus were carried out on a special rig with reciprocating motion, simulating the working conditions in a piston/cylinder unit in a pressure range from 5 to 32 MPa. Rig and field tests on machine- tool components and units and on hydraulic parts have confirmed the test data.

Elevated Serum Hepcidin Levels during an Intensified Training Period in Well-Trained Female Long-Distance Runners

PubMed Central

Ishibashi, Aya; Maeda, Naho; Sumi, Daichi; Goto, Kazushige

2017-01-01

Iron is essential for providing oxygen to working muscles during exercise, and iron deficiency leads to decreased exercise capacity during endurance events. However, the mechanism of iron deficiency among endurance athletes remains unclear. In this study, we compared iron status between two periods involving different training regimens. Sixteen female long-distance runners participated. Over a seven-month period, fasting blood samples were collected during their regular training period (LOW; middle of February) and during an intensified training period (INT; late of August) to determine blood hematological, iron, and inflammatory parameters. Three-day food diaries were also assessed. Body weight and lean body mass did not differ significantly between LOW and INT, while body fat and body fat percentage were significantly lower in INT (p < 0.05). Blood hemoglobin, serum ferritin, total protein, and iron levels, total iron-binding capacity, and transferrin saturation did not differ significantly between the two periods. Serum hepcidin levels were significantly higher during INT than LOW (p < 0.05). Carbohydrate and iron intakes from the daily diet were significantly higher during INT than LOW (p < 0.05). In conclusion, an elevated hepcidin level was observed during an intensified training period in long-distance runners, despite an apparently adequate daily intake of iron. PMID:28335426

Elevated Serum Hepcidin Levels during an Intensified Training Period in Well-Trained Female Long-Distance Runners.

PubMed

Ishibashi, Aya; Maeda, Naho; Sumi, Daichi; Goto, Kazushige

2017-03-14

Iron is essential for providing oxygen to working muscles during exercise, and iron deficiency leads to decreased exercise capacity during endurance events. However, the mechanism of iron deficiency among endurance athletes remains unclear. In this study, we compared iron status between two periods involving different training regimens. Sixteen female long-distance runners participated. Over a seven-month period, fasting blood samples were collected during their regular training period (LOW; middle of February) and during an intensified training period (INT; late of August) to determine blood hematological, iron, and inflammatory parameters. Three-day food diaries were also assessed. Body weight and lean body mass did not differ significantly between LOW and INT, while body fat and body fat percentage were significantly lower in INT ( p < 0.05). Blood hemoglobin, serum ferritin, total protein, and iron levels, total iron-binding capacity, and transferrin saturation did not differ significantly between the two periods. Serum hepcidin levels were significantly higher during INT than LOW ( p < 0.05). Carbohydrate and iron intakes from the daily diet were significantly higher during INT than LOW ( p < 0.05). In conclusion, an elevated hepcidin level was observed during an intensified training period in long-distance runners, despite an apparently adequate daily intake of iron.

Iron-regulated biofilm formation in Staphylococcus aureus Newman requires ica and the secreted protein Emp.

PubMed

Johnson, Miranda; Cockayne, Alan; Morrissey, Julie A

2008-04-01

Staphylococcus aureus biofilm formation is induced in iron-restricted growth conditions in vitro. In this study, we showed that Emp and Eap play important roles in low-iron-induced biofilm formation of S. aureus Newman. Eap and Emp are secreted proteins which are non-covalently attached to the S. aureus cell surface and have previously been implicated in a number of aspects of S. aureus pathogenesis. We showed here that the transcription of these important virulence factors is induced by growth in low-iron medium, reflective of the in vivo environment. Our results show that iron regulation of Eap and Emp is Fur independent. However, Fur is required for full induction of eap and emp expression in low-iron conditions. In this study, we demonstrated that in addition to Fur, low-iron-induced biofilm formation requires Sae, Agr, and SarA. In iron-restricted growth conditions, Sae and Agr are essential for Emp and Eap expression and hence for biofilm formation, whereas SarA appears to have a less-significant role. We also showed that expression of the ica operon is required for biofilm formation in iron-restricted growth conditions. We demonstrated that in fact, ica is required for the expression of the important multifunctional virulence determinants eap and emp.

Iron-Regulated Biofilm Formation in Staphylococcus aureus Newman Requires ica and the Secreted Protein Emp▿

PubMed Central

Johnson, Miranda; Cockayne, Alan; Morrissey, Julie A.

2008-01-01

Staphylococcus aureus biofilm formation is induced in iron-restricted growth conditions in vitro. In this study, we showed that Emp and Eap play important roles in low-iron-induced biofilm formation of S. aureus Newman. Eap and Emp are secreted proteins which are non-covalently attached to the S. aureus cell surface and have previously been implicated in a number of aspects of S. aureus pathogenesis. We showed here that the transcription of these important virulence factors is induced by growth in low-iron medium, reflective of the in vivo environment. Our results show that iron regulation of Eap and Emp is Fur independent. However, Fur is required for full induction of eap and emp expression in low-iron conditions. In this study, we demonstrated that in addition to Fur, low-iron-induced biofilm formation requires Sae, Agr, and SarA. In iron-restricted growth conditions, Sae and Agr are essential for Emp and Eap expression and hence for biofilm formation, whereas SarA appears to have a less-significant role. We also showed that expression of the ica operon is required for biofilm formation in iron-restricted growth conditions. We demonstrated that in fact, ica is required for the expression of the important multifunctional virulence determinants eap and emp. PMID:18268030

Biogeochemical gradients above a coal tar DNAPL.

PubMed

Scherr, Kerstin E; Backes, Diana; Scarlett, Alan G; Lantschbauer, Wolfgang; Nahold, Manfred

2016-09-01

Naturally occurring distribution and attenuation processes can keep hydrocarbon emissions from dense non aqueous phase liquids (DNAPL) into the adjacent groundwater at a minimum. In a historically coal tar DNAPL-impacted site, the de facto absence of a plume sparked investigations regarding the character of natural attenuation and DNAPL resolubilization processes at the site. Steep vertical gradients of polycyclic aromatic hydrocarbons, microbial community composition, secondary water quality and redox-parameters were found to occur between the DNAPL-proximal and shallow waters. While methanogenic and mixed-electron acceptor conditions prevailed close to the DNAPL, aerobic conditions and very low dissolved contaminant concentrations were identified in three meters vertical distance from the phase. Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) proved to be an efficient tool to characterize the behavior of the present complex contaminant mixture. Medium to low bioavailability of ferric iron and manganese oxides of aquifer samples was detected via incubation with Shewanella alga and evidence for iron and manganese reduction was collected. In contrast, 16S rDNA phylogenetic analysis revealed the absence of common iron reducing bacteria. Aerobic hydrocarbon degraders were abundant in shallow horizons, while nitrate reducers were dominating in deeper aquifer regions, in addition to a low relative abundance of methanogenic archaea. Partial Least Squares - Canonical Correspondence Analysis (PLS-CCA) suggested that nitrate and oxygen concentrations had the greatest impact on aquifer community structure in on- and offsite wells, which had a similarly high biodiversity (H' and Chao1). Overall, slow hydrocarbon dissolution from the DNAPL appears to dominate natural attenuation processes. This site may serve as a model for developing legal and technical strategies for the treatment of DNAPL-impacted sites where contaminant plumes are absent or shrinking. Copyright © 2015 Elsevier B.V. All rights reserved.

Point-of-use fortification of foods with micronutrient powders containing iron in children of preschool and school-age.

PubMed

De-Regil, Luz Maria; Jefferds, Maria Elena D; Peña-Rosas, Juan Pablo

2017-11-23

Approximately 600 million children of preschool and school age are anaemic worldwide. It is estimated that at least half of the cases are due to iron deficiency. Point-of-use fortification of foods with micronutrient powders (MNP) has been proposed as a feasible intervention to prevent and treat anaemia. It refers to the addition of iron alone or in combination with other vitamins and minerals in powder form, to energy-containing foods (excluding beverages) at home or in any other place where meals are to be consumed. MNPs can be added to foods either during or after cooking or immediately before consumption without the explicit purpose of improving the flavour or colour. To assess the effects of point-of-use fortification of foods with iron-containing MNP alone, or in combination with other vitamins and minerals on nutrition, health and development among children at preschool (24 to 59 months) and school (five to 12 years) age, compared with no intervention, a placebo or iron-containing supplements. In December 2016, we searched the following databases: CENTRAL, MEDLINE, Embase, BIOSIS, Science Citation Index, Social Science Citation Index, CINAHL, LILACS, IBECS, Popline and SciELO. We also searched two trials registers in April 2017, and contacted relevant organisations to identify ongoing and unpublished trials. Randomised controlled trials (RCTs) and quasi-RCTs trials with either individual or cluster randomisation. Participants were children aged between 24 months and 12 years at the time of intervention. For trials with children outside this age range, we included studies where we were able to disaggregate the data for children aged 24 months to 12 years, or when more than half of the participants were within the requisite age range. We included trials with apparently healthy children; however, we included studies carried out in settings where anaemia and iron deficiency are prevalent, and thus participants may have had these conditions at baseline. Two review authors independently assessed the eligibility of trials against the inclusion criteria, extracted data from included trials, assessed the risk of bias of the included trials and graded the quality of the evidence. We included 13 studies involving 5810 participants from Latin America, Africa and Asia. We excluded 38 studies and identified six ongoing/unpublished trials. All trials compared the provision of MNP for point-of-use fortification with no intervention or placebo. No trials compared the effects of MNP versus iron-containing supplements (as drops, tablets or syrup).The sample sizes in the included trials ranged from 90 to 2193 participants. Six trials included participants younger than 59 months of age only, four included only children aged 60 months or older, and three trials included children both younger and older than 59 months of age.MNPs contained from two to 18 vitamins and minerals. The iron doses varied from 2.5 mg to 30 mg of elemental iron. Four trials reported giving 10 mg of elemental iron as sodium iron ethylenediaminetetraacetic acid (NaFeEDTA), chelated ferrous sulphate or microencapsulated ferrous fumarate. Three trials gave 12.5 mg of elemental iron as microencapsulated ferrous fumarate. Three trials gave 2.5 mg or 2.86 mg of elemental iron as NaFeEDTA. One trial gave 30 mg and one trial provided 14 mg of elemental iron as microencapsulated ferrous fumarate, while one trial gave 28 mg of iron as ferrous glycine phosphate.In comparison with receiving no intervention or a placebo, children receiving iron-containing MNP for point-of-use fortification of foods had lower risk of anaemia prevalence ratio (PR) 0.66, 95% confidence interval (CI) 0.49 to 0.88, 10 trials, 2448 children; moderate-quality evidence) and iron deficiency (PR 0.35, 95% CI 0.27 to 0.47, 5 trials, 1364 children; moderate-quality evidence) and had higher haemoglobin (mean difference (MD) 3.37 g/L, 95% CI 0.94 to 5.80, 11 trials, 2746 children; low-quality evidence).Only one trial with 115 children reported on all-cause mortality (zero cases; low-quality evidence). There was no effect on diarrhoea (risk ratio (RR) 0.97, 95% CI 0.53 to 1.78, 2 trials, 366 children; low-quality evidence). Point-of-use fortification of foods with MNPs containing iron reduces anaemia and iron deficiency in preschool- and school-age children. However, information on mortality, morbidity, developmental outcomes and adverse effects is still scarce.

Amorphous metal composites

DOEpatents

Byrne, Martin A.; Lupinski, John H.

1984-01-01

An improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite.

Phase III randomized trial comparing intravenous to oral iron in patients with cancer-related iron deficiency anemia not on erythropoiesis stimulating agents.

PubMed

Noronha, Vanita; Joshi, Amit; Patil, Vijay Maruti; Banavali, Shripad D; Gupta, Sudeep; Parikh, Purvish M; Marfatia, Shalaka; Punatar, Sachin; More, Sucheta; Goud, Supriya; Nakti, Dipti; Prabhash, Kumar

2018-04-01

We aimed to find the optimal route of iron supplementation in patients with malignancy and iron deficiency (true or functional) anemia not receiving erythropoiesis stimulating agents (ESA). Adult patients with malignancy requiring chemotherapy, hemoglobin (Hb) <12 g/dL and serum ferritin <100 mcg/mL, transferrin saturation <20% or hypochromic red blood cells >10% were randomized to intravenous (IV) iron sucrose or oral ferrous sulfate. The primary endpoint was change in Hb from baseline to 6 weeks. Secondary endpoints included blood transfusion, quality of life (QoL), toxicity, response and overall survival. A total of 192 patients were enrolled over 5 years: 98 on IV arm and 94 on oral arm. Median age was 51 years; over 95% patients had solid tumors. The mean absolute increase in Hb at 6 weeks was 0.11 g/dL (standard deviation [SD]: 1.48) in IV arm and -0.16 g/dL (SD: 1.36) in oral arm, P = 0.23. Twenty-three percent patients on IV iron and 18% patients on oral iron had a rise in Hb of ≥1 g/dL at 6 weeks, P = 0.45. Thirteen patients (13.3%) on the IV iron arm and 14 patients (14.9%) on the oral arm required blood transfusion, P = 1.0. Gastrointestinal toxicity (any grade) developed in 41% patients on IV iron and 44% patients on oral iron, P = 1.0. 5 patients on IV iron and none on oral iron had hypersensitivity, P = 0.06. QoL was not significantly different between the two arms. IV iron was not superior to oral iron in patients with malignancy on chemotherapy and iron deficiency anemia. © 2017 John Wiley & Sons Australia, Ltd.

Widespread epigenomic, transcriptomic and proteomic differences between hip osteophytic and articular chondrocytes in osteoarthritis.

PubMed

Steinberg, Julia; Brooks, Roger A; Southam, Lorraine; Bhatnagar, Sahir; Roumeliotis, Theodoros I; Hatzikotoulas, Konstantinos; Zengini, Eleni; Wilkinson, J Mark; Choudhary, Jyoti S; McCaskie, Andrew W; Zeggini, Eleftheria

2018-05-08

To identify molecular differences between chondrocytes from osteophytic and articular cartilage tissue from OA patients. We investigated genes and pathways by combining genome-wide DNA methylation, RNA sequencing and quantitative proteomics in isolated primary chondrocytes from the cartilaginous layer of osteophytes and matched areas of low- and high-grade articular cartilage across nine patients with OA undergoing hip replacement surgery. Chondrocytes from osteophytic cartilage showed widespread differences to low-grade articular cartilage chondrocytes. These differences were similar to, but more pronounced than, differences between chondrocytes from osteophytic and high-grade articular cartilage, and more pronounced than differences between high- and low-grade articular cartilage. We identified 56 genes with significant differences between osteophytic chondrocytes and low-grade articular cartilage chondrocytes on all three omics levels. Several of these genes have known roles in OA, including ALDH1A2 and cartilage oligomeric matrix protein, which have functional genetic variants associated with OA from genome-wide association studies. An integrative gene ontology enrichment analysis showed that differences between osteophytic and low-grade articular cartilage chondrocytes are associated with extracellular matrix organization, skeletal system development, platelet aggregation and regulation of ERK1 and ERK2 cascade. We present a first comprehensive view of the molecular landscape of chondrocytes from osteophytic cartilage as compared with articular cartilage chondrocytes from the same joints in OA. We found robust changes at genes relevant to chondrocyte function, providing insight into biological processes involved in osteophyte development and thus OA progression.

Reactive oxygen species levels control NF-κB activation by low dose deferasirox in erythroid progenitors of low risk myelodysplastic syndromes.

PubMed

Meunier, Mathieu; Ancelet, Sarah; Lefebvre, Christine; Arnaud, Josiane; Garrel, Catherine; Pezet, Mylène; Wang, Yan; Faure, Patrice; Szymanski, Gautier; Duployez, Nicolas; Preudhomme, Claude; Biard, Denis; Polack, Benoit; Cahn, Jean-Yves; Moulis, Jean Marc; Park, Sophie

2017-12-01

Anemia is a frequent cytopenia in myelodysplastic syndromes (MDS) and most patients require red blood cell transfusion resulting in iron overload (IO). Deferasirox (DFX) has become the standard treatment of IO in MDS and it displays positive effects on erythropoiesis. In low risk MDS samples, mechanisms improving erythropoiesis after DFX treatment remain unclear. Herein, we addressed this question by using liquid cultures with iron overload of erythroid precursors treated with low dose of DFX (3μM), which corresponds to DFX 5 mg/kg/day, an unusual dose used for iron chelation. We highlight a decreased apoptosis rate and an increased proportion of cycling cells, both leading to higher proliferation rates. The iron chelation properties of low dose DFX failed to activate the Iron Regulatory Proteins and to support iron depletion, but low dose DFX dampers intracellular reactive oxygen species. Furthermore low concentrations of DFX activate the NF-κB pathway in erythroid precursors triggering anti-apoptotic and anti-inflammatory signals. Establishing stable gene silencing of the Thioredoxin (TRX) 1 genes, a NF-κB modulator, showed that fine-tuning of reactive oxygen species (ROS) levels regulates NF-κB. These results justify a clinical trial proposing low dose DFX in MDS patients refractory to erythropoiesis stimulating agents.

Reactive oxygen species levels control NF-κB activation by low dose deferasirox in erythroid progenitors of low risk myelodysplastic syndromes

PubMed Central

Meunier, Mathieu; Ancelet, Sarah; Lefebvre, Christine; Arnaud, Josiane; Garrel, Catherine; Pezet, Mylène; Wang, Yan; Faure, Patrice; Szymanski, Gautier; Duployez, Nicolas; Preudhomme, Claude; Biard, Denis; Polack, Benoit; Cahn, Jean-Yves; Moulis, Jean Marc; Park, Sophie

2017-01-01

Anemia is a frequent cytopenia in myelodysplastic syndromes (MDS) and most patients require red blood cell transfusion resulting in iron overload (IO). Deferasirox (DFX) has become the standard treatment of IO in MDS and it displays positive effects on erythropoiesis. In low risk MDS samples, mechanisms improving erythropoiesis after DFX treatment remain unclear. Herein, we addressed this question by using liquid cultures with iron overload of erythroid precursors treated with low dose of DFX (3μM), which corresponds to DFX 5 mg/kg/day, an unusual dose used for iron chelation. We highlight a decreased apoptosis rate and an increased proportion of cycling cells, both leading to higher proliferation rates. The iron chelation properties of low dose DFX failed to activate the Iron Regulatory Proteins and to support iron depletion, but low dose DFX dampers intracellular reactive oxygen species. Furthermore low concentrations of DFX activate the NF-κB pathway in erythroid precursors triggering anti-apoptotic and anti-inflammatory signals. Establishing stable gene silencing of the Thioredoxin (TRX) 1 genes, a NF-κB modulator, showed that fine-tuning of reactive oxygen species (ROS) levels regulates NF-κB. These results justify a clinical trial proposing low dose DFX in MDS patients refractory to erythropoiesis stimulating agents. PMID:29285268

78 FR 54478 - Endangered and Threatened Wildlife and Plants; Permits; Low-Effect Habitat Conservation Plan for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-04

... the Utah Prairie Dog in Iron County, Utah AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice... Draft Low-effect Habitat Conservation Plan for the Utah prairie dog in Iron County, Utah, for review and... Conservation Plan for the Utah prairie dog in Iron County, Utah. The Iron County Commission has prepared a...

The Statin–Iron Nexus: Anti-Inflammatory Intervention for Arterial Disease Prevention

PubMed Central

DePalma, Ralph G.; Shamayeva, Galina; Chow, Bruce K.

2013-01-01

Objectives. We postulated the existence of a statin–iron nexus by which statins improve cardiovascular disease outcomes at least partially by countering proinflammatory effects of excess iron stores. Methods. Using data from a clinical trial of iron (ferritin) reduction in advanced peripheral arterial disease, the Iron and Atherosclerosis Study, we compared effects of ferritin levels versus high-density lipoprotein to low-density lipoprotein ratios (both were randomization variables) on clinical outcomes in participants receiving and not receiving statins. Results. Statins increased high-density lipoprotein to low-density lipoprotein ratios and reduced ferritin levels by noninteracting mechanisms. Improved clinical outcomes were associated with lower ferritin levels but not with improved lipid status. Conclusions. There are commonalities between the clinical benefits of statins and the maintenance of physiologic iron levels. Iron reduction may be a safe and low-cost alternative to statins. PMID:23409890

Upgrading of consumer characteristics of granulated solid fuel from mixture of low-grade coal and biomass

NASA Astrophysics Data System (ADS)

Kuzmina, J. S.; Milovanov, O. Yu; Sinelshchikov, V. A.; Sytchev, G. A.; Zaichenko, V. M.

2015-11-01

Effect of torrefaction on consumer characteristics of fuel pellets made of low-grade and agricultural waste is shown. Data on the volatile content, ash content, calorific value and hygroscopicity for initial pellets and pellets, heat-treated at various temperatures are presented. The experimental study of the combustion process of initial and heat-treated pellets showed that torrefaction of pellets leads to a decreasing of the ignition temperature and an increasing of the efficiency of boiler plant.

Experimental Study on Purification of Low Grade Diatomite

NASA Astrophysics Data System (ADS)

Xiao, Liguang; Pang, Bo

2017-04-01

This paper presented an innovation for purification of low grade diatomite(DE) by grinding, ultrasonic pretreatment, acid leaching of closed stirring and calcination. The optimum process parameters of DE purification were obtained, the characterizations of original and purified DE were determined by SEM and BET. The results showed that the specific surface area of DE increased from 12.65m2/g to 23.23m2/g, which increased by 45.54%. SEM analysis revealed that the pore structure of purified DE was dredged highly.

Oral Iron Supplementation After Blood Donation

PubMed Central

Kiss, Joseph E.; Brambilla, Donald; Glynn, Simone A.; Mast, Alan E.; Spencer, Bryan R.; Stone, Mars; Kleinman, Steven H.; Cable, Ritchard G.

2016-01-01

IMPORTANCE Although blood donation is allowed every 8 weeks in the United States, recovery of hemoglobin to the currently accepted standard (12.5 g/dL) is frequently delayed, and some donors become anemic. OBJECTIVE To determine the effect of oral iron supplementation on hemoglobin recovery time (days to recovery of 80% of hemoglobin removed) and recovery of iron stores in iron-depleted (“low ferritin,” ≤26 ng/mL) and iron-replete (“higher ferritin,” >26 ng/mL) blood donors. DESIGN, SETTING, AND PARTICIPANTS Randomized, nonblinded clinical trial of blood donors stratified by ferritin level, sex, and age conducted in 4 regional blood centers in the United States in 2012. Included were 215 eligible participants aged 18 to 79 years who had not donated whole blood or red blood cells within 4 months. INTERVENTIONS One tablet of ferrous gluconate (37.5 mg of elemental iron) daily or no iron for 24 weeks (168 days) after donating a unit of whole blood (500 mL). MAIN OUTCOMES AND MEASURES Time to recovery of 80% of the postdonation decrease in hemoglobin and recovery of ferritin level to baseline as a measure of iron stores. RESULTS The mean baseline hemoglobin levels were comparable in the iron and no-iron groups and declined from a mean (SD) of 13.4 (1.1) g/dL to 12.0 (1.2) g/dL after donation in the low-ferritin group and from 14.2 (1.1) g/dL to 12.9 (1.2) g/dL in the higher-ferritin group. Compared with participants who did not receive iron supplementation, those who received iron supplementation had shortened time to 80% hemoglobin recovery in both the low-ferritin and higher-ferritin groups. Recovery of iron stores in all participants who received supplements took a median of 76 days (IQR, 20–126); for participants not taking iron, median recovery time was longer than 168 days (IQR, 147->168 days; P < .001). Without iron supplements, 67% of participants did not recover iron stores by 168 days. Low-Ferritin Group (≤26 ng/mL) Higher-Ferritin Group (>26 ng/mL) IronNo IronIronNo Iron Time to 80% hemoglobin recovery, mean (IQR), d32 (30–34)158 (126–>168)31 (29–33)78 (66–95) Time to recovery of baseline ferritin levels, median (IQR), d21 (12–84)>168 (128–>168)107 (75–141)>168 (>168–>168) CONCLUSIONS AND RELEVANCE Among blood donors with normal hemoglobin levels, low-dose iron supplementation, compared with no supplementation, reduced time to 80% recovery of the postdonation decrease in hemoglobin concentration in donors with low ferritin (≤26 ng/mL) or higher ferritin (>26 ng/mL). TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01555060 PMID:25668261

Application Of Bacterial Iron Reduction For The Removal Of Iron Impurities From Industrial Silica Sand And Kaolin

NASA Astrophysics Data System (ADS)

Zegeye, A.; Yahaya, S.; Fialips, C. I.; White, M.; Manning, D. A.; Gray, N.

2008-12-01

Biogeochemical evidence exists to support the potential importance of crystalline or amorphous Fe minerals as electron acceptor for Fe reducing bacteria in soils and subsurface sediments. This microbial metabolic activity can be exploited as alternative method in different industrial applications. For instance, the removal of ferric iron impurities from minerals for the glass and paper industries currently rely on physical and chemical treatments having substantial economical and environmental disadvantages. The ability to remove iron by other means, such as bacterial iron reduction, may reduce costs, allow lower grade material to be mined, and improve the efficiency of mineral processing. Kaolin clay and silica sand are used in a wide range of industrial applications, particularly in paper, ceramics and glass manufacturing. Depending on the geological conditions of deposition, they are often associated with iron (hydr)oxides that are either adsorbed to the mineral surfaces or admixed as separate iron bearing minerals. In this study, we have examined the Fe(III) removal efficiency from kaolin and silica sand by a series of iron- reducing bacteria from the Shewanella species (S. alga BrY, S. oneidensis MR-1, S. putrefaciens CN32 and S. putrefaciens ATCC 8071) in the presence of anthraquinone 2,6 disulfonate (AQDS). We have also investigated the effectiveness of a natural organic matter, extracted with the silica sand, as a substitute to AQDS for enhancing Fe(III) reduction kinetics. The microbial reduction of Fe(III) was achieved using batch cultures under non-growth conditions. The rate and the extent of Fe(III) reduction was monitored as a function of the initial Fe(III) content, Shewanella species and temperature. The bacterially- treated minerals were analyzed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) to observe any textural and mineralogical transformation. The whiteness and ISO brightness of the kaolin was also measured by spectrophotometry for quality testing. All Shewanella species were able to couple the oxidation of lactate to the reduction of Fe(III) associated with the kaolins and silica sands. However, there are differences among species with respect to the rate and extent of iron leaching. S. putrefaciens ATCC 8071 is the most effective, with a 10% increase in kaolin whiteness and 4% increase in ISO brightness in less than 5 days.

Intersections of pathways involving biotin and iron relative to therapeutic mechanisms for progressive multiple sclerosis.

PubMed

Heidker, Rebecca M; Emerson, Mitchell R; LeVine, Steven M

2016-12-01

While there are a variety of therapies for relapsing remitting multiple sclerosis (MS), there is a lack of treatments for progressive MS. An early study indicated that high dose biotin therapy has beneficial effects in approximately 12-15% of patients with progressive MS. The mechanisms behind the putative improvements seen with biotin therapy are not well understood, but have been postulated to include: 1) improving mitochondrial function which is impaired in MS, 2) increasing synthesis of lipids and cholesterol to facilitate remyelination, and 3) affecting gene expression. We suggest one reason that a greater percentage of patients with MS didn't respond to biotin therapy is the inaccessibility or lack of other nutrients, such as iron. In addition to biotin, iron (or heme) is necessary for energy production, biosynthesis of cholesterol and lipids, and for some protective mechanisms. Both biotin and iron are required for myelination during development, and by inference, remyelination. However, iron can also play a role in the pathology of MS. Increased deposition of iron can occur in some CNS structures possibly promoting oxidative damage while low iron levels can occur in other areas. Thus, the potential, detrimental effects of iron need to be considered together with the need for iron to support metabolic demands associated with repair and/or protective processes. We propose the optimal utilization of iron may be necessary to maximize the beneficial effects of biotin. This review will examine the interactions between biotin and iron in pathways that may have therapeutic or pathogenic implications for MS.

Separation of Iron Phase and P-Bearing Slag Phase from Gaseous-Reduced, High-Phosphorous Oolitic Iron Ore at 1473 K (1200 °C) by Super Gravity

NASA Astrophysics Data System (ADS)

Gao, Jintao; Zhong, Yiwei; Guo, Lei; Guo, Zhancheng

2016-04-01

In situ observation on the morphology evolution and phosphorous migration of gaseous-reduced, high-phosphorous oolitic iron ore during the melting process was carried out with a high-temperature confocal scanning laser microscope. The results showed that 1473 K (1200 °C) was a critical temperature at which the gangue minerals started to form into the slag phase while the iron grains remained in a solid state; in addition, the phosphorus remained in the slag phase. Since the separation of iron grains and P-bearing slag was not achieved at the low temperature under the conventional conditions, separate experiments of the iron phase and the P-bearing slag phase from gaseous-reduced, high-phosphorous oolitic iron ore at 1473 K (1200 °C) by super gravity were carried out in this study. Based on the iron-slag separation by super gravity, phosphorus was removed effectively from the iron phase at the temperature below the melting point of iron. Iron grains moved along the super-gravity direction, joined, and concentrated as the iron phase on the filter, whereas the slag phase containing apatite crystals broke through the barriers of the iron grains and went through the filter. Consequently, increasing the gravity coefficient was definitely beneficial for the separation of the P-bearing slag phase from the iron phase. With the gravity coefficient of G = 1200, the mass fractions of separated slag and iron phases were close to their respective theoretical values, and the mass fraction of MFe in the separated iron phase was up to 98.09 wt pct and that of P was decreased to 0.083 wt pct. The recovery of MFe in the iron phase and that of P in the slag phase were up to 99.19 and 95.83 pct, respectively.

Determination of the low molecular weight fraction of food-grade carrageenans.

PubMed

Spichtig, Véronique; Austin, Sean

2008-01-01

Recently there has been some debate regarding the presence and associated health risk of low molecular weight carrageenan in foodstuffs. Unfortunately measurement of the low molecular weight tail (LMT) of food-grade carrageenans (defined here as the carrageenan having relative molecular mass (Mr) below 50,000) is not trivial, largely due to its low abundance. So far methods employing light scattering have been unsuccessful in producing reproducible results, probably due to the poor detector response at low masses. In this work a method based on high performance size exclusion chromatography coupled to a refractive index detector (HPSEC-RI) has been used for the measurement of the LMT in food-grade carrageenan ingredients and in a carrageenan-containing finished product (a jelly). Over the course of half a year, 19 measurements were made on a reference carrageenan; the results demonstrated that the method had excellent reproducibility. Applied to a number of different carrageenan ingredients, it was found that, in general, the LMT represents less than 8% of the total carrageenan in ingredients, and under the correct conditions increases little during food processing. The data also indicated that pH appears to be a critical factor during food processing and pH levels below 4.0 should be avoided.

The effectiveness of graded activity for low back pain in occupational healthcare.

PubMed

Steenstra, I A; Anema, J R; Bongers, P M; de Vet, H C W; Knol, D L; van Mechelen, W

2006-11-01

Low back pain is a common medical and social problem associated with disability and absence from work. Knowledge on effective return to work (RTW) interventions is scarce. To determine the effectiveness of graded activity as part of a multistage RTW programme. Randomised controlled trial. Occupational healthcare. 112 workers absent from work for more than eight weeks due to low back pain were randomised to either graded activity (n = 55) or usual care (n = 57). Graded activity, a physical exercise programme aimed at RTW based on operant-conditioning behavioural principles. The number of days off work until first RTW for more then 28 days, total number of days on sick leave during follow up, functional status, and severity of pain. Follow up was 26 weeks. Graded activity prolonged RTW. Median time until RTW was equal to the total number of days on sick leave and was 139 (IQR = 69) days in the graded activity group and 111 (IQR = 76) days in the usual care group (hazard ratio = 0.52, 95% CI 0.32 to 0.86). An interaction between a prior workplace intervention and graded activity, together with a delay in the start of the graded activity intervention, explained most of the delay in RTW (hazard ratio = 0.86, 95% CI 0.40 to 1.84 without prior intervention and 0.39, 95% CI 0.19 to 0.81 with prior intervention). Graded activity did not improve pain or functional status clinically significantly. Graded activity was not effective for any of the outcome measures. Different interventions combined can lead to a delay in RTW. Delay in referral to graded activity delays RTW. In implementing graded activity special attention should be paid to the structure and process of care.

Interphase Transformations at Metal (Copper, Iron)-Polymer Gel-Electrolyte Interfaces

NASA Astrophysics Data System (ADS)

Lyamina, G. V.; Dubinina, O. V.; Vaitulevich, E. A.; Mokrousov, G. M.

2018-07-01

The results from studies of the interface boundaries between metals (copper and iron) and gel electrolyte based on methacrylic copolymers are organized systematically. In contrast to processes in liquid electrolytes, a number of key features of the reactions that occur at such interfaces are revealed: a diffusion limiting stage; a lack of reverse reactions; and the formation of coordination compounds of metal ions with the functional groups of polymers, the stabilities of which are several orders of magnitude greater than that of coordination with their low-molecular weight counterparts. It is shown that processes which employ polymeric organogels can be used for the careful cleaning of the metal surfaces, and for the formation of a desired phase composition on the latter.

Carbon deposition in the Bosch process with ruthenium and ruthenium-iron alloy catalysts. M.S. Thesis. Final Report, Jan. 1981 - Jul. 1982

NASA Technical Reports Server (NTRS)

Manning, M. P.; Reid, R. C.; Sophonpanich, C.

1982-01-01

The effectiveness of ruthenium and the alloys 50Ru50Fe and 33Ru67Fe as alternatives to iron, nickel, and cobalt catalysts in recovering oxygen from metabolic carbon dioxide was investigated. Carbon deposition boundaries over the unsupported alloys are reported. Experiments were also carried out over 50Ru50Fe and 97Ru3Fe3 catalysts supported on gamma-alumina to determine their performance in the synthesis of low molecular weight olefins. High production of ethylene and propylene would be beneficial for an improvement of an overall Bosch process, as a gas phase containing high olefin content would enhance carbon deposition in a Bosch reactor.

Siderophore-producing bacteria from a sand dune ecosystem and the effect of sodium benzoate on siderophore production by a potential isolate.

PubMed

Gaonkar, Teja; Nayak, Pramoda Kumar; Garg, Sandeep; Bhosle, Saroj

2012-01-01

Bioremediation in natural ecosystems is dependent upon the availability of micronutrients and cofactors, of which iron is one of the essential elements. Under aerobic and alkaline conditions, iron oxidizes to Fe(+3) creating iron deficiency. To acquire this essential growth-limiting nutrient, bacteria produce low-molecular-weight, high-affinity iron chelators termed siderophores. In this study, siderophore-producing bacteria from rhizosphere and nonrhizosphere areas of coastal sand dunes were isolated using a culture-dependent approach and were assigned to 8 different genera with the predominance of Bacillus sp. Studies on the ability of these isolates to grow on sodium benzoate revealed that a pigmented bacterial culture TMR2.13 identified as Pseudomonas aeruginosa showed growth on mineral salts medium (MSM) with 2% of sodium benzoate and produced a yellowish fluorescent siderophore identified as pyoverdine. This was inhibited above 54 μM of added iron in MSM with glucose without affecting growth, while, in presence of sodium benzoate, siderophore was produced even up to the presence of 108 μM of added iron. Increase in the requirement of iron for metabolism of aromatic compounds in ecosystems where the nutrient deficiencies occur naturally would be one of the regulating factors for the bioremediation process.

Siderophore-Producing Bacteria from a Sand Dune Ecosystem and the Effect of Sodium Benzoate on Siderophore Production by a Potential Isolate

PubMed Central

Gaonkar, Teja; Nayak, Pramoda Kumar; Garg, Sandeep; Bhosle, Saroj

2012-01-01

Bioremediation in natural ecosystems is dependent upon the availability of micronutrients and cofactors, of which iron is one of the essential elements. Under aerobic and alkaline conditions, iron oxidizes to Fe+3 creating iron deficiency. To acquire this essential growth-limiting nutrient, bacteria produce low-molecular-weight, high-affinity iron chelators termed siderophores. In this study, siderophore-producing bacteria from rhizosphere and nonrhizosphere areas of coastal sand dunes were isolated using a culture-dependent approach and were assigned to 8 different genera with the predominance of Bacillus sp. Studies on the ability of these isolates to grow on sodium benzoate revealed that a pigmented bacterial culture TMR2.13 identified as Pseudomonas aeruginosa showed growth on mineral salts medium (MSM) with 2% of sodium benzoate and produced a yellowish fluorescent siderophore identified as pyoverdine. This was inhibited above 54 μM of added iron in MSM with glucose without affecting growth, while, in presence of sodium benzoate, siderophore was produced even up to the presence of 108 μM of added iron. Increase in the requirement of iron for metabolism of aromatic compounds in ecosystems where the nutrient deficiencies occur naturally would be one of the regulating factors for the bioremediation process. PMID:22629215

Medicago truncatula natural resistance-associated macrophage Protein1 is required for iron uptake by rhizobia-infected nodule cells.

PubMed

Tejada-Jiménez, Manuel; Castro-Rodríguez, Rosario; Kryvoruchko, Igor; Lucas, M Mercedes; Udvardi, Michael; Imperial, Juan; González-Guerrero, Manuel

2015-05-01

Iron is critical for symbiotic nitrogen fixation (SNF) as a key component of multiple ferroproteins involved in this biological process. In the model legume Medicago truncatula, iron is delivered by the vasculature to the infection/maturation zone (zone II) of the nodule, where it is released to the apoplast. From there, plasma membrane iron transporters move it into rhizobia-containing cells, where iron is used as the cofactor of multiple plant and rhizobial proteins (e.g. plant leghemoglobin and bacterial nitrogenase). MtNramp1 (Medtr3g088460) is the M. truncatula Natural Resistance-Associated Macrophage Protein family member, with the highest expression levels in roots and nodules. Immunolocalization studies indicate that MtNramp1 is mainly targeted to the plasma membrane. A loss-of-function nramp1 mutant exhibited reduced growth compared with the wild type under symbiotic conditions, but not when fertilized with mineral nitrogen. Nitrogenase activity was low in the mutant, whereas exogenous iron and expression of wild-type MtNramp1 in mutant nodules increased nitrogen fixation to normal levels. These data are consistent with a model in which MtNramp1 is the main transporter responsible for apoplastic iron uptake by rhizobia-infected cells in zone II. © 2015 American Society of Plant Biologists. All Rights Reserved.

Scalable Production of Si Nanoparticles Directly from Low Grade Sources for Lithium-Ion Battery Anode.

PubMed

Zhu, Bin; Jin, Yan; Tan, Yingling; Zong, Linqi; Hu, Yue; Chen, Lei; Chen, Yanbin; Zhang, Qiao; Zhu, Jia

2015-09-09

Silicon, one of the most promising candidates as lithium-ion battery anode, has attracted much attention due to its high theoretical capacity, abundant existence, and mature infrastructure. Recently, Si nanostructures-based lithium-ion battery anode, with sophisticated structure designs and process development, has made significant progress. However, low cost and scalable processes to produce these Si nanostructures remained as a challenge, which limits the widespread applications. Herein, we demonstrate that Si nanoparticles with controlled size can be massively produced directly from low grade Si sources through a scalable high energy mechanical milling process. In addition, we systematically studied Si nanoparticles produced from two major low grade Si sources, metallurgical silicon (∼99 wt % Si, $1/kg) and ferrosilicon (∼83 wt % Si, $0.6/kg). It is found that nanoparticles produced from ferrosilicon sources contain FeSi2, which can serve as a buffer layer to alleviate the mechanical fractures of volume expansion, whereas nanoparticles from metallurgical Si sources have higher capacity and better kinetic properties because of higher purity and better electronic transport properties. Ferrosilicon nanoparticles and metallurgical Si nanoparticles demonstrate over 100 stable deep cycling after carbon coating with the reversible capacities of 1360 mAh g(-1) and 1205 mAh g(-1), respectively. Therefore, our approach provides a new strategy for cost-effective, energy-efficient, large scale synthesis of functional Si electrode materials.

Immunomodulatory Effects of Soybeans and Processed Soy Food Compounds.

PubMed

Tezuka, Hiroyuki; Imai, Shinjiro

2015-01-01

Inflammation is an immune response against both internal and external antigens in organisms, particularly in mammals, and includes both uncontrolled chronic and low-grade inflammations. Uncontrolled chronic inflammation often leads to severe diseases such as vascular disease, arthritis, cancer, diabete, allergy, and autoimmunity. On the other hand, low-grade inflammation is recognized as a relationship between obesity and risk of metabolic syndrome. Elevated production of pro-inflammatory cytokines and mediators is commonly observed in patients with uncontrolled or low-grade inflammation-associated diseases. Plants have been generated phytochemicals to overcome inflammations and infections through evolution. Phytochemicals belong to alkaloids, polyphenols, flavonoids, coumarins, and terpenoids. The consumption of soybeans plays a role in immune modulation through their components such as isoflavones, saponins, and anthocyanins. Recently, it was reported that the application of phytochemicals into patients with inflammatory diseases improves their symptoms. Therefore, it is important to identify novel phytochemicals with immunomodulatory activities. This review introduces and discusses recent advances and patents regarding soybean or processed soy food compounds which exhibit immunomodulatory activity in immune diseases, particularly allergy, by mediating the suppression of inflammatory pathways.

Alkyl radical generation by an intramolecular homolytic substitution reaction between iron (II) and trialkylsulfonium groups.

PubMed

Jungen, Stefan; Chen, Peter

2018-05-16

Intramolecular, homolytic substitution reactions between iron (II) species and various trialkylsulfonium groups were directly observed in the gas phase upon collision induced dissociation. In spite of the notoriously low reduction potential of trialkylsulfonium species and the mismatched oxidation potential of iron (II), the reactions proceed at moderate collision energies, forming an alkyl radical as well as a thioether coordinated to the iron. In contrast to classical homolytic substitutions, the attacking radical is a "metalloradical", namely iron (II) that is oxidized to iron (III) during the reaction. With this process we demonstrate that the conceptually analogous, putative radical generation step in Radical S-Adenosyl Methionine Enzymes is possible and plausible. Further, we show that this kind of reaction only occurs in constrained systems with a defined geometry. Combining experimental measurements with DFT studies and NBO analyses allowed us to gain insights into the reactivity and transition states of these systems. Based on our findings, we challenge the notion of a collinear transition state in the radical generation step of Radical SAM Enzymes and propose it to be bent instead. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-Vivo Imaging of Cell Migration Using Contrast Enhanced MRI and SVM Based Post-Processing.

PubMed

Weis, Christian; Hess, Andreas; Budinsky, Lubos; Fabry, Ben

2015-01-01

The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of T2*-weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods.

Electro activation of persulfate using iron sheet as low-cost electrode: the role of the operating conditions.

PubMed

Silveira, Jefferson E; Cardoso, Tais O; Barreto-Rodrigues, Marcio; Zazo, Juan A; Casas, José A

2018-05-01

This work assesses the role of the operational conditions upon the electro-activation of persulfate (PS) using sacrificed iron electrode as a continuous low-cost Fe 2+ source. An aqueous phenol solution (100 mg L -1 ) was selected as model effluent. The studied variables include current density (1-10 mA cm -2 ), persulfate concentration (0.7-2.85 g L -1 ), temperature (30-90°C) and the solution conductivity (2.7-20.7 mS cm -1 ) using Na 2 SO 4 and NaCl as supporting electrolyte. A mineralization degree of around 80% with Na 2 SO 4 and 92% in presence of NaCl was achieved at 30°C using 2.15 g L -1 PS at the lowest current density tested (1 mA cm -2 ). Besides PS concentration, temperature was the main variable affecting the process. In the range of 30-70°C, it showed a positive effect, achieving TOC conversion above 95% (using Na 2 SO 4 under the previous conditions) along with a significant increase in iron sludge, which adversely affects the economy of the process. A lumped and simplified kinetic model based on persulfate consumption and TOC mineralization is suggested. The activation energy obtained for the TOC decay was 29 kJ mol -1 . An estimated operating cost of US$ 3.00 per m 3 was obtained, demonstrating the economic feasibility of this process.

Low cost solar array project. Experimental process system development unit for producing semiconductor-grade silicon using the silane-to-silicon process

NASA Technical Reports Server (NTRS)

1980-01-01

Technical activities are reported in the design of process, facilities, and equipment for producing silicon at a rate and price comensurate with production goals for low cost solar cell modules. The silane-silicone process has potential for providing high purity poly-silicon on a commercial scale at a price of fourteen dollars per kilogram by 1986, (1980 dollars). Commercial process, economic analysis, process support research and development, and quality control are discussed.

Ferric reductase activity of low molecular weight human milk fraction is associated with enhanced iron solubility and uptake in Caco-2 cells.

PubMed

Pullakhandam, Raghu; Nair, Madhavan Krishnapillai; Kasula, Sunanda; Kilari, Sreenivasulu; Thippande, Tippeswamy Gowda

2008-09-19

It is known that the fractional absorption of extrinsic iron from human milk is higher in infants and adults. A low molecular weight milk fraction has been proposed to increase the bioavailability of iron from human milk. Nevertheless, the mechanisms remained elusive. Here in we demonstrate ferric reductase activity (Km7.73x10(-6)M) in low molecular weight human milk fraction (10kF, filtrate derived from ultra filtration of milk whey through 10kDa cutoff membrane), which increased ferric iron solubility and iron uptake in Caco-2 cells. The 10kF fraction was as effective as ascorbic acid (1:20 iron to ascorbic acid) in increasing the ferric iron solubility and uptake in Caco-2 cells. Further, gel filtration chromatography on peptide column led to co-elution of ferric reductase and iron solubilization activities at an apparent molecular mass of <1500Da. Interestingly, only these fractions containing ferric reductase activity also stimulated the uptake of iron in Caco-2 cells. Thus, it is concluded that human milk possesses ferric reductase activity and is associated with ferric iron solubilization and enhanced absorption.

Iron in non-hydroxyl radical mediated photochemical processes for dye degradation: Catalyst or inhibitor?

PubMed

Wu, Bingdang; Zhang, Shujuan; Li, Xuchun; Liu, Xitong; Pan, Bingcai

2015-07-01

The acetylacetone (AA) mediated photochemical process has been proven as an efficient approach for decoloration. For azo dyes, the UV/AA process was several to more than ten times more efficient than the UV/H2O2 process. Iron is one of the most common elements on the earth. It is well known that iron can improve the UV/H2O2 process through thermal Fenton and photo-Fenton reactions. What will be the role of iron in the UV/AA process? Could iron-AA complexes act as photocatalysts in environmental remediation? To answer these questions, the photo-degradation of an azo dye, Acid Orange 7 (AO7), was conducted under the variant combinations of AA with iron species in both ionic (Fe2+, Fe3+) and complex (Fe(AA)3) forms. The pseudo-first-order decoloration rate constants of AO7 in these photochemical processes followed such an order: UV/Fe(II)/AA

Iron K shell line, a probe of low energy cosmic rays in SNRs

NASA Astrophysics Data System (ADS)

Koyama, Katsuji; Sato, Tamotsu

2016-06-01

Since the discovery of non thermal power-law X-rays at the rim of SN1006 by Koyama et al. (1995), this feature has been established to be evidence of high energy cosmic rays (HECRs). The HECRs are created by a diffuse shock acceleration process. Accordingly low energy cosmic rays (LECRS) must be presented as the injector of this acceleration process. We found for the first time that the K-shell line from neutral iron at 6.4 keV is good tracer of LECRs in SNRs. This paper present the observational facts for LECRs from intermediate aged SNRs, 3C391, Kes79, Kes 78 and W44 in the Scutum Arm region (see figure, Sato et al. 2014, 2015). Two SNRs, 3C391 and W44, exhibit recombining plasma (RP), an unusual structure in the frame work of the standard SNR evolution scenario. Together with the RP, we discuss the origin of LECRs in the SNRs.

From Happenstance to Success.

ERIC Educational Resources Information Center

Berchtold, Nancy

1984-01-01

Ninth grade boys are motivated by a project which involves them in making designs for their t-shirts and a class banner, using a paint called DEKA Iron-On. A dried painting executed with this medium can be transferred to synthetic fabrics. (RM)

Elucidation of Iron Gettering Mechanisms in Boron-Implanted Silicon Solar Cells

DOE PAGES

Laine, Hannu S.; Vahanissi, Ville; Liu, Zhengjun; ...

2017-12-15

To facilitate cost-effective manufacturing of boron-implanted silicon solar cells as an alternative to BBr 3 diffusion, we performed a quantitative test of the gettering induced by solar-typical boron-implants with the potential for low saturation current density emitters (< 50 fA/cm 2). We show that depending on the contamination level and the gettering anneal chosen, such boron-implanted emitters can induce more than a 99.9% reduction in bulk iron point defect concentration. The iron point defect results as well as synchrotron-based Nano-X-ray-fluorescence investigations of iron precipitates formed in the implanted layer imply that, with the chosen experimental parameters, iron precipitation is themore » dominant gettering mechanism, with segregation-based gettering playing a smaller role. We reproduce the measured iron point defect and precipitate distributions via kinetics modeling. First, we simulate the structural defect distribution created by the implantation process, and then we model these structural defects as heterogeneous precipitation sites for iron. Unlike previous theoretical work on gettering via boron- or phosphorus-implantation, our model is free of adjustable simulation parameters. The close agreement between the model and experimental results indicates that the model successfully captures the necessary physics to describe the iron gettering mechanisms operating in boron-implanted silicon. Furthermore, this modeling capability allows high-performance, cost-effective implanted silicon solar cells to be designed.« less

Elucidation of Iron Gettering Mechanisms in Boron-Implanted Silicon Solar Cells

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

Laine, Hannu S.; Vahanissi, Ville; Liu, Zhengjun

To facilitate cost-effective manufacturing of boron-implanted silicon solar cells as an alternative to BBr 3 diffusion, we performed a quantitative test of the gettering induced by solar-typical boron-implants with the potential for low saturation current density emitters (< 50 fA/cm 2). We show that depending on the contamination level and the gettering anneal chosen, such boron-implanted emitters can induce more than a 99.9% reduction in bulk iron point defect concentration. The iron point defect results as well as synchrotron-based Nano-X-ray-fluorescence investigations of iron precipitates formed in the implanted layer imply that, with the chosen experimental parameters, iron precipitation is themore » dominant gettering mechanism, with segregation-based gettering playing a smaller role. We reproduce the measured iron point defect and precipitate distributions via kinetics modeling. First, we simulate the structural defect distribution created by the implantation process, and then we model these structural defects as heterogeneous precipitation sites for iron. Unlike previous theoretical work on gettering via boron- or phosphorus-implantation, our model is free of adjustable simulation parameters. The close agreement between the model and experimental results indicates that the model successfully captures the necessary physics to describe the iron gettering mechanisms operating in boron-implanted silicon. Furthermore, this modeling capability allows high-performance, cost-effective implanted silicon solar cells to be designed.« less

Assessing the Roles of Iron, Macronutrients and Wet deposition in Controlling Phytoplankton Growth in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

NASA Astrophysics Data System (ADS)

Sedwick, P.; Mulholland, M. R.; Najjar, R.; Bernhardt, P. W.; Price, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

2016-02-01

The role of iron supply in regulating phytoplankton production in high-nutrient, low-chlorophyll ocean regions has been well established. Less clear, however, is the importance of iron for phytoplankton processes in other oceanic settings, such as coastal and oligotrophic waters, where differential changes in the supply and removal of dissolved iron (dFe) can result in limitation or co-limitation of growth due to iron deficiency. One such region of interest is the Mid-Atlantic Bight (MAB), where previous field experiments have provided some evidence of co-limitation of algal growth by nitrogen and iron. In summer 2014 we conducted field sampling and shipboard experiments to assess the role of iron and macronutrient availability in controlling primary production in seasonally oligotrophic waters over the MAB continental slope, with a focus on the the impacts of wet deposition. Our results indicate that nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by availability of phosphorus; we found no evidence for a deficiency in dFe, which was present at concentrations in the range 0.3-0.9 nM. Phytoplankton growth was clearly stimulated by the addition of natural rainwater, suggesting that summer rain events stimulate primary production in the MAB by contributing new nitrogen (primarily as ammonium) and phosphorus, whilst maintaining iron-replete conditions.

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore

PubMed Central

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-01-01

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process. PMID:27374991

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore.

PubMed

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-07-04

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process.

Genomic and metagenomic analysis of microbes in a soil environment affected by the 2011 Great East Japan Earthquake tsunami.

PubMed

Hiraoka, Satoshi; Machiyama, Asako; Ijichi, Minoru; Inoue, Kentaro; Oshima, Kenshiro; Hattori, Masahira; Yoshizawa, Susumu; Kogure, Kazuhiro; Iwasaki, Wataru

2016-01-14

The Great East Japan Earthquake of 2011 triggered large tsunami waves, which flooded broad areas of land along the Pacific coast of eastern Japan and changed the soil environment drastically. However, the microbial characteristics of tsunami-affected soil at the genomic level remain largely unknown. In this study, we isolated microbes from a soil sample using general low-nutrient and seawater-based media to investigate microbial characteristics in tsunami-affected soil. As expected, a greater proportion of strains isolated from the tsunami-affected soil than the unaffected soil grew in the seawater-based medium. Cultivable strains in both the general low-nutrient and seawater-based media were distributed in the genus Arthrobacter. Most importantly, whole-genome sequencing of four of the isolated Arthrobacter strains revealed independent losses of siderophore-synthesis genes from their genomes. Siderophores are low-molecular-weight, iron-chelating compounds that are secreted for iron uptake; thus, the loss of siderophore-synthesis genes indicates that these strains have adapted to environments with high-iron concentrations. Indeed, chemical analysis confirmed the investigated soil samples to be rich in iron, and culture experiments confirmed weak cultivability of some of these strains in iron-limited media. Furthermore, metagenomic analyses demonstrated over-representation of denitrification-related genes in the tsunami-affected soil sample, as well as the presence of pathogenic and marine-living genera and genes related to salt-tolerance. Collectively, the present results would provide an example of microbial characteristics of soil disturbed by the tsunami, which may give an insight into microbial adaptation to drastic environmental changes. Further analyses on microbial ecology after a tsunami are envisioned to develop a deeper understanding of the recovery processes of terrestrial microbial ecosystems.

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.

Conversion of mill-scale waste to nanoscale zero valent iron (nZVI) for 'green' hydrogen generation via metal-steam reforming

NASA Astrophysics Data System (ADS)

Kesavan, Sathees Kumar

The Proton Exchange Membrane Fuel Cells (PEMFCs) are the most preferred and efficient energy conversion devices for automotive applications but demand high purity hydrogen which comes at a premium price. The currently pursued hydrogen generation methods suffer from issues such as, low efficiency, high cost, environmental non-benignity, and, in some cases, commercial non-viability. Many of these drawbacks including the CO contamination and, storage and delivery can be overcome by resorting to metal-steam reforming (MSR) using iron from steel industry's mill-scale waste. A novel solution-based room temperature technique using sodium borohydride (NaBH4) as the reducing agent has been developed that produces highly active nanoscale (30-40 nm) iron particles. A slightly modified version of this technique using a surfactant and water oil microemulsion resulted in the formation of 5 nm Fe particles. By using hydrazine (N2H4) as an inexpensive and more stable (compared to NaBH4) reductant, body centered cubic iron particles with edge dimensions ˜5 nm were obtained under mild solvothermal conditions in ethanol. The nanoscale zero valent iron (nZVI) powder showed improved kinetics and greater propensity for hydrogen generation than the coarser microscale iron obtained through traditional reduction techniques. To initiate and sustain the somewhat endothermic MSR process, a solar concentrator consisting of a convex polyacrylic sheet with aluminum reflective coating was fabricated. This unique combination of mill-scale waste as iron source, hydrazine as the reductant, mild process conditions for nZVI generation and solar energy as the impetus for actuating MSR, obviates several drawbacks plaguing the grand scheme of producing, storing and delivering pure and humidified H2 to a PEMFC stack.

Iron triggers λSo prophage induction and release of extracellular DNA in Shewanella oneidensis MR-1 biofilms.

PubMed

Binnenkade, Lucas; Teichmann, Laura; Thormann, Kai M

2014-09-01

Prophages are ubiquitous elements within bacterial chromosomes and affect host physiology and ecology in multiple ways. We have previously demonstrated that phage-induced lysis is required for extracellular DNA (eDNA) release and normal biofilm formation in Shewanella oneidensis MR-1. Here, we investigated the regulatory mechanisms of prophage λSo spatiotemporal induction in biofilms. To this end, we used a functional fluorescence fusion to monitor λSo activation in various mutant backgrounds and in response to different physiological conditions. λSo induction occurred mainly in a subpopulation of filamentous cells in a strictly RecA-dependent manner, implicating oxidative stress-induced DNA damage as the major trigger. Accordingly, mutants affected in the oxidative stress response (ΔoxyR) or iron homeostasis (Δfur) displayed drastically increased levels of phage induction and abnormal biofilm formation, while planktonic cells were not or only marginally affected. To further investigate the role of oxidative stress, we performed a mutant screen and identified two independent amino acid substitutions in OxyR (T104N and L197P) that suppress induction of λSo by hydrogen peroxide (H2O2). However, λSo induction was not suppressed in biofilms formed by both mutants, suggesting a minor role of intracellular H2O2 in this process. In contrast, addition of iron to biofilms strongly enhanced λSo induction and eDNA release, while both processes were significantly suppressed at low iron levels, strongly indicating that iron is the limiting factor. We conclude that uptake of iron during biofilm formation triggers λSo-mediated lysis of a subpopulation of cells, likely by an increase in iron-mediated DNA damage sensed by RecA. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Impact of thermal oxidation on chemical composition and magnetic properties of iron nanoparticles

NASA Astrophysics Data System (ADS)

Krajewski, Marcin; Brzozka, Katarzyna; Tokarczyk, Mateusz; Kowalski, Grzegorz; Lewinska, Sabina; Slawska-Waniewska, Anna; Lin, Wei Syuan; Lin, Hong Ming

2018-07-01

The main objective of this work is to study the influence of thermal oxidation on the chemical composition and magnetic properties of iron nanoparticles which were manufactured in a simple chemical reduction of Fe3+ ions coming from iron salt with sodium borohydride. The annealing processing was performed in an argon atmosphere containing the traces of oxygen to avoid spontaneous oxidation of iron at temperatures ranging from 200 °C to 800 °C. The chemical composition and magnetic properties of as-prepared and thermally-treated nanoparticles were determined by means of X-ray diffractometry, Raman spectroscopy, Mössbauer spectroscopy and vibrating sample magnetometry. Due to the magnetic interactions, the investigated iron nanoparticles tended to create the dense aggregates which were difficult to split even at low temperatures. This caused that there was no empty space between them, which led to their partial sintering at elevated temperatures. These features hindered their precise morphological observations using the electron microscopy techniques. The obtained results show that the annealing process up to 800 °C resulted in a progressive change in the chemical composition of as-prepared iron nanoparticles which was associated with their oxidation. As a consequence, their magnetic properties also depended on the annealing temperature. For instance, considering the values of saturation magnetization, its highest value was recorded for the as-prepared nanoparticles at 1 T and it equals 149 emu/g, while the saturation point for nanoparticles treated at 600 °C and higher temperatures was not reached even at the magnetic field of about 5 T. Moreover, a significant enhancement of coercivity was observed for the iron nanoparticles annealed over 600 °C.

Influence of artistic gymnastics on iron nutritional status and exercise-induced hemolysis in female athletes.

PubMed

Sureira, Thaiz Mattos; Amancio, Olga Silverio; Pellegrini Braga, Josefina Aparecida

2012-08-01

This study evaluates the relationship between body iron losses and gains in artistic gymnastics female athletes. It shows that despite the low iron intake and exercise-induced hemolysis, iron deficiency or iron-deficiency anemia does not occur, but partial changes in the hematological profile do. The hypothesis that gymnasts' nutritional behavior contributes to anemia, which may be aggravated by exercise-induced hemolysis, led to this cross-sectional study, conducted with 43 female artistic gymnasts 6-16 yr old. The control group was formed by 40 nontraining girls, paired by age. Hemogram, serum iron, ferritin, soluble transferrin receptor, haptoglobin, total and fractional bilirubin, Type I urine, and parasitologic and occult fecal blood tests were evaluated. The athletes presented mean hematimetric and serum iron values (p = .020) higher than those of the control group. The bilirubin result discarded any hemolytic alteration in both groups. The haptoglobin results were lower in the athlete group (p = .002), confirming the incidence of exercise-induced hemolysis. Both groups presented low iron intake. The results suggest that artistic gymnastics practice leads to exercise-induced hemolysis and partially changes the hematological profile, although not causing iron deficiency or iron-deficiency anemia, even in the presence of low iron intake.

Variation and inheritance of iron reductase activity in the roots of common bean (Phaseolus vulgaris L.) and association with seed iron accumulation QTL.

PubMed

Blair, Matthew W; Knewtson, Sharon Jb; Astudillo, Carolina; Li, Chee-Ming; Fernandez, Andrea C; Grusak, Michael A

2010-10-05

Iron deficiency anemia is a global problem which often affects women and children of developing countries. Strategy I plants, such as common bean (Phaseolus vulgaris L.) take up iron through a process that involves an iron reduction mechanism in their roots; this reduction is required to convert ferric iron to ferrous iron. Root absorbed iron is critical for the iron nutrition of the plant, and for the delivery of iron to the shoot and ultimately the seeds. The objectives of this study were to determine the variability and inheritance for iron reductase activity in a range of genotypes and in a low × high seed iron cross (DOR364 x G19833), to identify quantitative trait loci (QTL) for this trait, and to assess possible associations with seed iron levels. The experiments were carried out with hydroponically grown plants provided different amounts of iron varying between 0 and 20 μM Fe(III)-EDDHA. The parents, DOR364 and G19833, plus 13 other cultivated or wild beans, were found to differ in iron reductase activity. Based on these initial experiments, two growth conditions (iron limited and iron sufficient) were selected as treatments for evaluating the DOR364 × G19833 recombinant inbred lines. A single major QTL was found for iron reductase activity under iron-limited conditions (1 μM Fe) on linkage group b02 and another major QTL was found under iron sufficient conditions (15 μM Fe) on linkage group b11. Associations between the b11 QTL were found with several QTL for seed iron. Genes conditioning iron reductase activity in iron sufficient bean plants appear to be associated with genes contributing to seed iron accumulation. Markers for bean iron reductase (FRO) homologues were found with in silico mapping based on common bean synteny with soybean and Medicago truncatula on b06 and b07; however, neither locus aligned with the QTL for iron reductase activity. In summary, the QTL for iron reductase activity under iron limited conditions may be useful in environments where beans are grown in alkaline soils, while the QTL for iron reductase under sufficiency conditions may be useful for selecting for enhanced seed nutritional quality.

The Effects of Dietary Iron and Capsaicin on Hemoglobin, Blood Glucose, Insulin Tolerance, Cholesterol, and Triglycerides, in Healthy and Diabetic Wistar Rats.

PubMed

Márquez-Ibarra, Adriana; Huerta, Miguel; Villalpando-Hernández, Salvador; Ríos-Silva, Mónica; Díaz-Reval, María I; Cruzblanca, Humberto; Mancilla, Evelyn; Trujillo, Xóchitl

2016-01-01

Our aim was to assess the effects of dietary iron, and the compound capsaicin, on hemoglobin as well as metabolic indicators including blood glucose, cholesterol, triglycerides, insulin, and glucose tolerance. Our animal model was the Wistar rat, fed a chow diet, with or without experimentally induced diabetes. Diabetic males were fed control, low, or high-iron diets, the latter, with or without capsaicin. Healthy rats were fed identical diets, but without the capsaicin supplement. We then measured the parameters listed above, using the Student t-test and ANOVA, to compare groups. Healthy rats fed a low-iron diet exhibited significantly reduced total cholesterol and triglyceride levels, compared with rats fed a control diet. Significantly reduced blood lipid was also provoked by low dietary iron in diabetic rats, compared with those fed a control diet. Insulin, and glucose tolerance was only improved in healthy rats fed the low-iron diet. Significant increases in total cholesterol were found in diabetic rats fed a high-iron diet, compared with healthy rats fed the same diet, although no statistical differences were found for triglycerides. Hemoglobin levels, which were not statistically different in diabetic versus healthy rats fed the high-iron diet, fell when capsaicin was added. Capsaicin also provoked a fall in the level of cholesterol and triglycerides in diabetic animals, versus diabetics fed with the high iron diet alone. In conclusion, low levels of dietary iron reduced levels of serum triglycerides, hemoglobin, and cholesterol, and significantly improved insulin, and glucose tolerance in healthy rats. In contrast, a high-iron diet increased cholesterol significantly, with no significant changes to triglyceride concentrations. The addition of capsaicin to the high-iron diet (for diabetic rats) further reduced levels of hemoglobin, cholesterol, and triglycerides. These results suggest that capsaicin, may be suitable for the treatment of elevated hemoglobin, in patients.

Core Characteristics Deterioration due to Plastic Deformation

NASA Astrophysics Data System (ADS)

Kaido, Chikara; Arai, Satoshi

This paper discusses the effect of plastic deformation at core manufacturing on the characteristics of cores where non-oriented electrical steel sheets are used as core material. Exciting field and iron loss increase proportionally to plastic deformation in the case of rP<10, where rP is a ratio of plastic deformation to that at yield point. In this region, anomalous eddy currents increase because plastic deformations of crystalline grains are distributed and then the flux distribution is induced. In the case of rP>20, the deterioration tend to saturate, and the increases in magnetic field and iron loss are 1000 to 1500A/m and 2 to 4W/kg. They are related to grain size, and high grade with larger grain may have lager field increase and smaller iron loss increase. Anomalous eddy current losses scarcely increase in this region. In actual motors, the plastic deformation affects iron loss increase although exciting current increases a little.

Mothers' depressive symptoms and children's cognitive and social agency: Predicting first-grade cognitive functioning.

PubMed

Yan, Ni; Dix, Theodore

2016-08-01

Using data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (N = 1,364), the present study supports an agentic perspective; it demonstrates that mothers' depressive symptoms in infancy predict children's poor first-grade cognitive functioning because depressive symptoms predict children's low social and cognitive agency-low motivation to initiate social interaction and actively engage in activities. When mothers' depressive symptoms were high in infancy, children displayed poor first-grade cognitive functioning due to (a) tendencies to become socially withdrawn by 36 months and low in mastery motivation by 54 months and (b) tendencies for children's low agency to predict declines in mothers' sensitivity and cognitive stimulation. Findings suggest that mothers' depressive symptoms undermine cognitive development through bidirectional processes centered on children's low motivation to engage in social interaction and initiate and persist at everyday tasks. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Enabling iron pyrite (FeS2) and related ternary pyrite compounds for high-performance solar energy applications

NASA Astrophysics Data System (ADS)

Caban Acevedo, Miguel

The success of solar energy technologies depends not only on highly efficient solar-to-electrical energy conversion, charge storage or chemical fuel production, but also on dramatically reduced cost, to meet the future terawatt energy challenges we face. The enormous scale involved in the development of impactful solar energy technologies demand abundant and inexpensive materials, as well as energy-efficient and cost-effective processes. As a result, the investigation of semiconductor, catalyst and electrode materials made of earth-abundant and sustainable elements may prove to be of significant importance for the long-term adaptation of solar energy technologies on a larger scale. Among earth-abundant semiconductors, iron pyrite (cubic FeS2) has been considered the most promising solar energy absorber with the potential to achieve terawatt energy-scale deployment. Despite extensive synthetic progress and device efforts, the solar conversion efficiency of iron pyrite has remained below 3% since the 1990s, primarily due to a low open circuit voltage (V oc). The low photovoltage (Voc) of iron pyrite has puzzled scientists for decades and limited the development of cost-effective solar energy technologies based on this otherwise promising semiconductor. Here I report a comprehensive investigation of the syntheses and properties of iron pyrite materials, which reveals that the Voc of iron pyrite is limited by the ionization of a high density of intrinsic bulk defect states despite high density surface states and strong surface Fermi level pinning. Contrary to popular belief, bulk defects most-likely caused by intrinsic sulfur vacancies in iron pyrite must be controlled in order to enable this earth-abundant semiconductor for cost-effective and sustainable solar energy conversion. Lastly, the investigation of iron pyrite presented here lead to the discovery of ternary pyrite-type cobalt phosphosulfide (CoPS) as a highly-efficient earth-abundant catalyst material for electrochemical and solar energy driven hydrogen production.

Iron Deficiency Anemia: Problems in Diagnosis and Prevention at the Population Level.

PubMed

Pasricha, Sant-Rayn; Drakesmith, Hal

2016-04-01

Anemia is common among people living in low- and middle-income countries, and alleviation of the global burden of anemia is an essential global health target over the next decade. Estimates have attributed about half the cases of anemia worldwide to iron deficiency; a range of other causes probably make a similar overall contribution. Individuals living in low-income settings experience a simultaneous high burden of infection with inflammation and iron deficiency. At least in children, iron supplementation exacerbates the risk of infection in both malaria-endemic and nonendemic low-income countries, whereas iron deficiency is protective against clinical and severe malaria. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of iron bioavailability from different bread making processes using an in vitro intestinal cell model.

PubMed

Rodriguez-Ramiro, I; Brearley, C A; Bruggraber, S F A; Perfecto, A; Shewry, P; Fairweather-Tait, S

2017-08-01

Myo-inositol hexakisphosphate (IP6), is the main iron chelator in cereals and bread. The aim of this study was to investigate the effect of three commercial baking processes (sourdough, conventional yeast and Chorleywood Bread Making Process (CBP)) on the IP6 content of wholemeal bread, its impact on iron uptake in Caco-2 cells and the predicted bioavailability of iron from these breads with added iron, simulating a mixed-meal. The sourdough process fully degraded IP6 whilst the CBP and conventional processes reduced it by 75% compared with wholemeal flour. The iron released in solution after a simulated digestion was 8-fold higher in sourdough bread than with others but no difference in cellular iron uptake was observed. Additionally, when iron was added to the different breads digestions only sourdough bread elicited a significant ferritin response in Caco-2 cells (4.8-fold compared to the other breads) suggesting that sourdough bread could contribute towards improved iron nutrition. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Mechanical Behavior of Commercially Pure Titanium Weldments at Lower Temperatures

NASA Astrophysics Data System (ADS)

Gupta, R. K.; Anil Kumar, V.; Xavier, X. Roshan

2018-05-01

Commercially pure titanium is used for low-temperature applications due to good toughness attributed to single-phase microstructure (α). Electron beam welding (EBW) and gas tungsten arc welding (GTAW) processes have been used for welding two grades of commercially pure titanium (Grade 2 and Grade 4). Martensitic microstructure is found to be finer in the case of EBW joint as compared to GTAW joint due to faster rate of cooling in the former process. Weldments have been characterized to study the mechanical behavior at ambient (298 K) and cryogenic temperatures (20 and 77 K). Strength of weldments increases with the decrease in temperature, which is found to be more prominent in case of Grade 4 titanium as compared to Grade 2. Weld efficiency of Grade 4 is found to be higher at all the temperatures (ambient, 77 and 20 K). However, ultimate tensile strength/yield strength ratio is higher for Grade 2 as compared to Grade 4. % Elongation is found to increase/retained at cryogenic temperatures for Grade 2, and it is found to decrease for Grade 4. Electron backscattered diffraction analysis and transmission electron microscopy of deformed samples confirmed the presence of extensive twinning in Grade 2 and the presence of finer martensitic structure in Grade 4. Fractography analysis of tested specimens revealed the presence of cleavage facets in Grade 4 and dimples in specimens of Grade 2. Higher strength in Grade 4 is attributed to higher oxygen restricting the twin-assisted slip, which is otherwise prominent in Grade 2 titanium.

Improving the Desulfurization Degree of High-Grade Nickel Matte via a Two-Step Oxidation Roasting Process

NASA Astrophysics Data System (ADS)

Xi, Zhao; Wang, Zhixing; Li, Xinhai; Guo, Huajun; Yan, Guochun; Wang, Jiexi

2018-05-01

Generally, sulfur elimination from nickel matte was incomplete in the one-step oxidation roasting process. In this work, X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray spectroscopy, and chemical analysis of the roasted products were carried out to explain this phenomenon. The results indicated that the melting of heazlewoodite was the main limiting factor. Thereafter, the oxidation mechanism of high-grade nickel matte from room temperature to 1000 °C was studied. It was found that the transformation from heazlewoodite (Ni3S2) to nickel sulfide (NiS) took place from 400 °C to 520 °C. Considering that the melting temperature of NiS was much higher than that of Ni3S2, a low-temperature roasting step was suggested to suppress the melting of heazlewoodite. Under the optimum conditions (520 °C for 120 minutes followed by 800 °C for 80 minutes), the degree of desulfurization reached 99.52 pct. These results indicated that the two-step oxidation roasting method could be a promising process for producing low-sulfur calcine from high-grade nickel matte.

Genetic and biochemical investigations of the role of MamP in redox control of iron biomineralization in Magnetospirillum magneticum.

PubMed

Jones, Stephanie R; Wilson, Tiffany D; Brown, Margaret E; Rahn-Lee, Lilah; Yu, Yi; Fredriksen, Laura L; Ozyamak, Ertan; Komeili, Arash; Chang, Michelle C Y

2015-03-31

Magnetotactic bacteria have evolved complex subcellular machinery to construct linear chains of magnetite nanocrystals that allow the host cell to sense direction. Each mixed-valent iron nanoparticle is mineralized from soluble iron within a membrane-encapsulated vesicle termed the magnetosome, which serves as a specialized compartment that regulates the iron, redox, and pH environment of the growing mineral. To dissect the biological components that control this process, we have carried out a genetic and biochemical study of proteins proposed to function in iron mineralization. In this study, we show that the redox sites of c-type cytochromes of the Magnetospirillum magneticum AMB-1 magnetosome island, MamP and MamT, are essential to their physiological function and that ablation of one or both heme motifs leads to loss of function, suggesting that their ability to carry out redox chemistry in vivo is important. We also develop a method to heterologously express fully heme-loaded MamP from AMB-1 for in vitro biochemical studies, which show that its Fe(III)-Fe(II) redox couple is set at an unusual potential (-89 ± 11 mV) compared with other related cytochromes involved in iron reduction or oxidation. Despite its low reduction potential, it remains competent to oxidize Fe(II) to Fe(III) and mineralize iron to produce mixed-valent iron oxides. Finally, in vitro mineralization experiments suggest that Mms mineral-templating peptides from AMB-1 can modulate the iron redox chemistry of MamP.

Iron deficiency anemia

MedlinePlus

Anemia - iron deficiency ... iron from old red blood cells. Iron deficiency anemia develops when your body's iron stores run low. ... You may have no symptoms if the anemia is mild. Most of the time, ... slowly. Symptoms may include: Feeling weak or tired more often ...

Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides.

PubMed

Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

2011-06-01

Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

Characterization of solar-grade silicon produced by the SiF4-Na process

NASA Technical Reports Server (NTRS)

Sanjurjo, A.; Sancier, K. M.; Emerson, R. M.; Leach, S. C.; Minahan, J.

1986-01-01

A process was developed for producing low cost solar grade silicon by the reaction between SiF4 gas and sodium metal. The results of the characterization of the silicon are presented. These results include impurity levels, electronic properties of the silicon after crystal growth, and the performance of solar photovoltaic cells fabricated from wafers of the single crystals. The efficiency of the solar cells fabricated from semiconductor silicon and SiF4-Na silicon was the same.

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.

Assessing Biogenecity of Stromatolites: Return to the Facies

NASA Astrophysics Data System (ADS)

Shapiro, R. S.; Jameson, S.; Rutter, A.; McCarthy, K.; Planavsky, N. J.; Severson, M.

2013-12-01

The discovery of richly microfossiliferous cherty stromatolites near Schreiber and Kakabeka Falls, Ontario, in the 1.9 Ga Gunflint Iron Formation, firmly established the field of pre-Cambrian paleontology. In the half-century since this discovery, paradigm shifts in the ecology of the microfossils as well as the utility of stromatolites as biological markers has caused a re-evaluation of our understanding of the pre-Cambrian fossil record. This research summarizes facies evaluation of the two stromatolite marker beds in the Gunflint-correlative Biwabik Iron Formation of Minnesota. The centimeter-scale microstratigraphy of cores drilled through the central and eastern Mesabi Iron Range was coupled with field descriptions of outcrops and mines in both the Biwabik and Gunflint iron formations. Eight lithologic facies associated with the stromatolites are identified: A) Pebble conglomerate clasts ranging in size of 0.5-3 cm, syneresis cracks, and septarian nodules with medium to coarse grain matrix; B) siltstone with subparallel sub-mm to 5 cm magnetitic and non-magnetic bands; C) stromatolitic boundstone comprising stratiform, pseudocolumnar, domal, undulatory, flat-laminated, dendritic, columnar, and mico-digitate forms and oncoids 0.5 to 2 cm diameter; D) grainstone with medium to coarse siliceous and carbonate ooids and peloids; E) massive green crystalline beds with bands of magnetite, quartz, calcite, disseminated pyrite and localized ankerite; F) autobreccicated fabric of 0.3 to 10 mm clasts; G) medium to coarse sandstone; H) quartzite. Correlation between 11 cores near Hoyt Lakes and 9 cores through the basal stromatolite layer at the MinnTac Mine near Virginia revealed that stromatolites formed both on conglomerate and medium quartz sandstone. Multiple forms of stromatolite may occur in a vertical succession (flat-laminated to undulatory to psuedocolumnar to columnar) or a core may be dominated by one type, typically columnar-stratiform. Where stromatolites do not occur, the interval is autobrecciated with many clasts containing syneresis cracks. Flow-banded iron oxides in these layers are not stromatolitic but likely formed from fluid flow at the boundary between well- and poorly-cemented lithofacies. Mesostructure is similar between collection sites that are essentially unaltered, low-grade diagenetic, and amphibolite-grade metamorphic. Furthermore, mesostructure is consistent in most stromatolites throughout both layers in the Biwabik as well as the Gunflint. These new results provide a much broader context then previous studies and demonstrate that the upper and lower stromatolite horizons in the Biwabik and Gunflint iron ranges are formed in similar facies. Complexity in stromatolite forms occurs on the sub-meter scale, as would be expected for a nearshore, microbially mediated system. However, there appears to be a gradient in the degree of microbial control of stromatolite morphology, with both ';biogenic' and ';abiogenic' forms present. More broadly, this work highlights the importance of field and regional context when deciphering the significance of microbialites.

Iron fortification of infant formulas. American Academy of Pediatrics. Committee on Nutrition.

PubMed

1999-07-01

Despite the American Academy of Pediatrics' (AAP) strong endorsement for breastfeeding, most infants in the United States are fed some infant formula by the time they are 2 months old. The AAP Committee on Nutrition has strongly advocated iron fortification of infant formulas since 1969 as a way of reducing the prevalence of iron-deficiency anemia and its attendant sequelae during the first year.1 The 1976 statement titled "Iron Supplementation for Infants" delineated the rationale for iron supplementation, proposed daily dosages of iron, and summarized potential sources of iron in the infant diet.2 In 1989, the AAP Committee on Nutrition published a statement that addressed the issue of iron-fortified infant formulas3 and concluded that there was no convincing contraindication to iron-supplemented formulas and that continued use of "low-iron" formulas posed an unacceptable risk for iron deficiency during infancy. The current statement represents a scientific update and synthesis of the 1976 and 1989 statements with recommendations about the use of iron-fortified and low-iron formulas in term infants.

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.

Maize porridge enriched with a micronutrient powder containing low-dose iron as NaFeEDTA but not amaranth grain flour reduces anemia and iron deficiency in Kenyan preschool children.

PubMed

Macharia-Mutie, Catherine W; Moretti, Diego; Van den Briel, Natalie; Omusundi, Agnes M; Mwangi, Alice M; Kok, Frans J; Zimmermann, Michael B; Brouwer, Inge D

2012-09-01

Few studies have evaluated the impact of fortification with iron-rich foods such as amaranth grain and multi-micronutrient powder (MNP) containing low doses of highly bioavailable iron to control iron deficiency anemia (IDA) in children. We assessed the efficacy of maize porridge enriched with amaranth grain or MNP to reduce IDA in Kenyan preschool children. In a 16-wk intervention trial, children (n = 279; 12-59 mo) were randomly assigned to: unrefined maize porridge (control; 4.1 mg of iron/meal; phytate:iron molar ratio 5:1); unrefined maize (30%) and amaranth grain (70%) porridge (amaranth group; 23 mg of iron/meal; phytate:iron molar ratio 3:1); or unrefined maize porridge with MNP (MNP group; 6.6 mg iron/meal; phytate:iron molar ratio 2.6:1; 2.5 mg iron as NaFeEDTA). Primary outcomes were anemia and iron status with treatment effects estimated relative to control. At baseline, 38% were anemic and 30% iron deficient. Consumption of MNP reduced the prevalence of anemia [-46% (95% CI: -67, -12)], iron deficiency [-70% (95% CI: -89, -16)], and IDA [-75% (95% CI: -92, -20)]. The soluble transferrin receptor [-10% (95% CI: -16, -4)] concentration was lower, whereas the hemoglobin (Hb) [2.7 g/L (95% CI: 0.4, 5.1)] and plasma ferritin [40% (95% CI: 10, 95)] concentrations increased in the MNP group. There was no significant change in Hb or iron status in the amaranth group. Consumption of maize porridge fortified with low-dose, highly bioavailable iron MNP can reduce the prevalence of IDA in preschool children. In contrast, fortification with amaranth grain did not improve iron status despite a large increase in iron intake, likely due to high ratio of phytic acid:iron in the meal.

Rare earth elements in Hamersley BIF minerals

NASA Astrophysics Data System (ADS)

Alibert, Chantal

2016-07-01

Minerals from the Hamersley banded iron formation, Western Australia, were analyzed for Y and rare earth elements (YREEs) by laser ablation ICP-MS to investigate diagenetic pathways, from precursor phases to BIF minerals. One group of apatites carries the seawater REE signature, giving evidence that P and REEs, thoroughly scavenged from the water column by Si-ferrihydrite particles, were released upon microbial Fe3+ reductive dissolution of Si-ferrihydrite in pore-water and finally sequestered mainly in authigenic apatite. The absence of fractionation between apatite and seawater suggests that REE were first incorporated into an amorphous calcium phosphate as fully hydrated cations, i.e. as outer-sphere complexes. The iron oxides and carbonates carry only a small fraction of the whole-rock REE budget. Their REE patterns are distinctly enriched in Yb and show some M-type tetrad effect consistent with experimental Kd(REE) between solid and saline solution with low carbonate ion concentrations. It is deduced that hematite formed at an incipient stage of Fe2+-catalyzed dissolution of Si-ferrihydrite, via a dissolution-reprecipitation pathway. The REE pattern of greenalite, found as sub-micron particles in quartz in a chert-siderite sample, is consistent with its authigenic origin by precipitation in pore-water after dissolution of a small amount of Si-ferrihydrite. Magnetite carries very low YREEs (ppb-level), has an homogeneous pattern distinctly enriched in the mid-REEs compared to hematite, and includes a late population depleted in light-REEs, Ba and As. Magnetite forming aggregates and massive laminae is tentatively interpreted as reflecting some fluid-aided hematite-magnetite re-equilibration or transformation at low-grade metamorphic temperatures.

Micronutrient supplementation adherence and influence on the prevalences of anemia and iron, zinc and vitamin A deficiencies in preemies with a corrected age of six months

PubMed Central

de Freitas, Brunnella Alcantara Chagas; Lima, Luciana Moreira; Moreira, Maria Elisabeth Lopes; Priore, Silvia Eloiza; Henriques, Bruno David; Carlos, Carla Fernanda Lisboa Valente; Sabino, Jusceli Souza Nogueira; do Carmo Castro Franceschini, Sylvia

2016-01-01

OBJECTIVE: To analyze adherence to the recommended iron, zinc and multivitamin supplementation guidelines for preemies, the factors associated with this adherence, and the influence of adherence on the occurrence of anemia and iron, zinc and vitamin A deficiencies. METHODS: This prospective cohort study followed 58 preemies born in 2014 until they reached six months corrected age. The preemies were followed at a referral secondary health service and represented 63.7% of the preterm infants born that year. Outcomes of interest included high or low adherence to iron, zinc and multivitamin supplementation guidelines; prevalence of anemia; and prevalences of iron, zinc, and vitamin A deficiencies. The prevalence ratios were calculated by Poisson regression. RESULTS: Thirty-eight (65.5%) preemies presented high adherence to micronutrient supplementation guidelines. At six months of corrected age, no preemie had vitamin A deficiency. The prevalences of anemia, iron deficiency and zinc deficiency were higher in the low-adherence group but also concerning in the high-adherence group. Preemies with low adherence to micronutrient supplementation guidelines were 2.5 times more likely to develop anemia and 3.1 times more likely to develop zinc deficiency. Low maternal education level increased the likelihood of nonadherence to all three supplements by 2.2 times. CONCLUSIONS: Low maternal education level was independently associated with low adherence to iron, zinc and vitamin A supplementation guidelines in preemies, which impacted the prevalences of anemia and iron and zinc deficiencies at six months of corrected age. PMID:27626474

Iron Homeostasis in Mycobacterium tuberculosis: Mechanistic Insights into Siderophore-Mediated Iron Uptake

PubMed Central

2016-01-01

Mycobacterium tuberculosis requires iron for normal growth but faces a limitation of the metal ion due to its low solubility at biological pH and the withholding of iron by the mammalian host. The pathogen expresses the Fe3+-specific siderophores mycobactin and carboxymycobactin to chelate the metal ion from insoluble iron and the host proteins transferrin, lactoferrin, and ferritin. Siderophore-mediated iron uptake is essential for the survival of M. tuberculosis, as knockout mutants, which were defective in siderophore synthesis or uptake, failed to survive in low-iron medium and inside macrophages. But as excess iron is toxic due to its catalytic role in the generation of free radicals, regulation of iron uptake is necessary to maintain optimal levels of intracellular iron. The focus of this review is to present a comprehensive overview of iron homeostasis in M. tuberculosis that is discussed in the context of mycobactin biosynthesis, transport of iron across the mycobacterial cell envelope, and storage of excess iron. The clinical significance of the serum iron status and the expression of the iron-regulated protein HupB in tuberculosis (TB) patients is presented here, highlighting the potential of HupB as a marker, notably in extrapulmonary TB cases. PMID:27402628

Photo-Fenton oxidation of 3-amino-5-methylisoxazole: a by-product from biological breakdown of some pharmaceutical compounds.

PubMed

Souza, Bianca M; Marinho, Belisa A; Moreira, Francisca C; Dezotti, Márcia W C; Boaventura, Rui A R; Vilar, Vítor J P

2017-03-01

The present study aims to assess the removal of 3-amino-5-methylisoxazole (AMI), a recalcitrant by-product resulting from the biological breakdown of some pharmaceuticals, applying a solar photo-Fenton process assisted by ferrioxalate complexes (SPFF) (Fe 3+ /H 2 O 2 /oxalic acid/UVA-Vis) and classical solar photo-Fenton process (SPF) (Fe 2+ /H 2 O 2 /UVA-Vis). The oxidation ability of SPFF was evaluated at different iron/oxalate molar ratios (1:3, 1:6, and 1:9, with [total iron] = 3.58 × 10 -2  mM and [oxalic acid] = 1.07 × 10 -1 , 2.14 × 10 -1 and 3.22 × 10 -1  mM, respectively) and pH values (3.5-6.5), using low iron contents (2.0 mg Fe 3+ L -1 ). Additionally, the use of other organic ligands such as citrate and ethylenediamine-N,N'-disuccinic acid (EDDS) was tested. The oxidation power of the classical SPF was assessed at different pH values (2.8-4.0) using 2.0 mg Fe 2+ per liter. Furthermore, the effect of AMI concentration (2-20 mg L -1 ), presence of inorganic ions (Cl - , SO 4 2- , NO 3 - , HCO 3 - , NH 4 + ), and radical scavengers (sodium azide and D-mannitol) on the SPF method at pH 3.5 was also assessed. Experiments were done using a lab-scale photoreactor with a compound parabolic collector (CPC) under simulated solar radiation. A pilot-scale assay was conducted using the best operation conditions. While at near neutral pH, an iron/oxalate molar ratio of 1:9 led to the removal of 72 % of AMI after 90 min of SPFF, at pH 3.5, an iron/oxalate molar ratio of 1:3 was enough to achieve complete AMI degradation (below the detection limit) after 30 min of reaction. The SPF process at pH 3.5 underwent a slower AMI degradation, reaching total AMI degradation after 40 min of reaction. The scale up of SPF process showed a good reproducibility. Oxalic and oxamic acids were identified as the main low-molecular-weight carboxylic acids detected during the pilot-scale SPF reaction. Graphical abstract ᅟ.

Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

NASA Astrophysics Data System (ADS)

Shekhovtsova, Anastasia P.; Karengin, Alexander G.

2016-08-01

This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flammable dispersed water-saltorganic compositions on laboratory plasma stand. All the experimental results are confirmed by calculations.

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

S.K. Kawatra; B. Anamerie; T.C. Eisele

The pig iron nugget process was developed as an alternative to the traditional blast furnace process by Kobe Steel. The process aimed to produce pig iron nuggets, which have similar chemical and physical properties to blast furnace pig iron, in a single step. The pig iron nugget process utilizes coal instead of coke and self reducing and fluxing dried green balls instead of pellets and sinters. In this process the environmental emissions caused by coke and sinter production, and energy lost between pellet induration (heat hardening) and transportation to the blast furnace can be eliminated. The objectives of this researchmore » were to (1) produce pig iron nuggets in the laboratory, (2) characterize the pig iron nugget produced and compare them with blast furnace pig iron, (3) investigate the furnace temperature and residence time effects on the pig iron nugget production, and (4) optimize the operational furnace temperatures and residence times. The experiments involved heat treatment of self reducing and fluxing dried green balls at various furnace temperatures and residence times. Three chemically and physically different products were produced after the compete reduction of iron oxides to iron depending on the operational furnace temperatures and/or residence times. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets. The increase in the carbon content of the system as a function of furnace temperature and/or residence time dictated the formation of these products. The direct reduced iron, transition direct reduced iron, and pig iron nuggets produced were analyzed for their chemical composition, degree of metallization, apparent density, microstructure and microhardness. In addition, the change in the carbon content of the system with the changing furnace temperature and/or residence time was detected by optical microscopy and Microhardness measurements. The sufficient carbon dissolution required for the production of pig iron nuggets was determined. It was determined that pig iron nuggets produced had a high apparent density (6.7-7.2 gr/cm3), highly metallized, slag free structure, high iron content (95-97%), high microhardness values (> 325 HVN) and microstructure similar to white cast iron. These properties made them a competitive alternative to blast furnace pig iron.« less

Nitrogenase activity of Herbaspirillum seropedicae grown under low iron levels requires the products of nifXorf1 genes.

PubMed

Klassen, Giseli; de Oliveira Pedrosa, Fábio; de Souza, Emanuel M; Yates, M Geoffrey; Rigo, Liu Un

2003-07-29

Herbaspirillum seropedicae strains mutated in the nifX or orf1 genes showed 90% or 50% reduction in nitrogenase activity under low levels of iron or molybdenum respectively. Mutations in nifX or orf1 genes did not affect nif gene expression since a nifH::lacZ fusion was fully active in both mutants. nifX and the contiguous gene orf1 are essential for maximum nitrogen fixation under iron limitation and are probably involved in synthesis of nitrogenase iron or iron-molybdenum clusters.

Differential Roles of Iron Storage Proteins in Maintaining the Iron Homeostasis in Mycobacterium tuberculosis

PubMed Central

Tyagi, Anil K.

2017-01-01

Ferritins and bacterioferritins are iron storage proteins that represent key players in iron homeostasis. Several organisms possess both forms of ferritins, however, their relative physiological roles are less understood. Mycobacterium tuberculosis possesses both ferritin (BfrB) and bacterioferritin (BfrA), playing an essential role in its pathogenesis as reported by us earlier. This study provides insights into the role of these two proteins in iron homeostasis by employing M. tuberculosis bfr mutants. Our data suggests that BfrA is required for efficient utilization of stored iron under low iron conditions while BfrB plays a crucial role as the major defense protein under excessive iron conditions. We show that these two proteins provide protection against oxidative stress and hypoxia. Iron incorporation study showed that BfrB has higher capacity for storing iron than BfrA, which augurs well for efficient iron quenching under iron excess conditions. Moreover, iron release assay demonstrated that BfrA has 3 times superior ability to release stored iron emphasizing its requirement for efficient iron release under low iron conditions, facilitated by the presence of heme. Thus, for the first time, our observations suggest that the importance of BfrA or BfrB separately might vary depending upon the iron situation faced by the cell. PMID:28060867

The Biogeochemical Role of Antarctic Krill and Baleen Whales in Southern Ocean Nutrient Cycling.

NASA Astrophysics Data System (ADS)

Ratnarajah, L.

2015-12-01

Iron limits primary productivity in large areas of the Southern Ocean. It has been suggested that baleen whales form a crucial part of biogeochemical cycling processes through the consumption of nutrient-rich krill and subsequent defecation, but evidence on their contribution is scarce. We analysed the concentration of iron in Antarctic krill and baleen whale faeces and muscle. Iron concentrations in Antarctic krill were over 1 million times higher, and whale faecal matter were almost 10 million times higher than typical Southern Ocean High Nutrient Low Chlorophyll seawater concentrations. This suggests that Antarctic krill act as a reservoir of in in Southern Ocean surface waters, and that baleen whales play an important role in converting this fixed iron into a liquid form in their faeces. We developed an exploratory model to examine potential contribution of blue, fin and humpback whales to the Southern Ocean iron cycle to explore the effect of the recovery of great whales to historical levels. Our results suggest that pre-exploitation populations of blue whales and, to a lesser extent fin and humpback whales, could have contributed to the more effective recycling of iron in surface waters, resulting in enhanced phytoplankton production. This enhanced primary productivity is estimated to be: 8.3 x 10-5 to 15 g C m-2 yr-1 (blue whales), 7 x 10-5 to 9 g C m-2 yr-1 (fin whales), and 10-5 to 1.7 g C m-2 yr-1 (humpback whales). To put these into perspective, current estimates of primary production in the Southern Ocean from remotely sensed ocean colour are in the order of 57 g C m-2 yr-1 (south of 50°). The high degree of uncertainty around the magnitude of these increases in primary productivity is mainly due to our limited quantitative understanding of key biogeochemical processes including iron content in krill, krill consumption rates by whales, persistence of iron in the photic zone, bioavailability of retained iron, and carbon-to-iron ratio of phytoplankton. We are actively working on addressing these unknowns.

Effects of Na2SO4 on iron and nickel reduction in a high-iron and low-nickel laterite ore

NASA Astrophysics Data System (ADS)

Wang, Xiao-ping; Sun, Ti-chang; Chen, Chao; Kou, Jue

2018-04-01

This study investigates the reactions of Na2SO4 and its effects on iron and nickel reduction in the roasting of a high-iron and low-nickel laterite ore through gas composition, X-ray diffraction, and scanning electron microscope analyses. Results showed that a reduction reaction of Na2SO4 to SO2 was performed with roasting up to 600°C. However, no clear influence on iron and nickel reductions appeared, because only a small amount of Na2SO4 reacted to produce SO2. Na2SO4 reacted completely at 1000°C, mainly producing troilite and nepheline, which remarkably improves selective reduction of nickel. Furthermore, the production of low-melting-point minerals, including troilite and nepheline, accelerated nickel reduction and delayed iron reduction, which is attributed to the concurrent production of magnesium magnetite, whose structure is more stable than the structure of magnetite. Reduction reactions of Na2SO4 resulted in weakening of the reduction atmosphere, and the main product of Na2SO4 changed and delayed the reduction of iron. Eventually, iron metallization was effectively controlled during laterite ore reduction roasting, leading to iron mainly being found in wustite and high iron-containing olivine.

Low Cost Solar Array Project. Feasibility of the silane process for producing semiconductor-grade silicon. Final report, October 1975-March 1979

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

Not Available

1979-06-01

The commercial production of low-cost semiconductor-grade silicon is an essential requirement of the JPL/DOE (Department of Energy) Low-Cost Solar Array (LSA) Project. A 1000-metric-ton-per-year commercial facility using the Union Carbide Silane Process will produce molten silicon for an estimated price of $7.56/kg (1975 dollars, private financing), meeting the DOE goal of less than $10/kg. Conclusions and technology status are reported for both contract phases, which had the following objectives: (1) establish the feasibility of Union Carbide's Silane Process for commercial application, and (2) develop an integrated process design for an Experimental Process System Development Unit (EPSDU) and a commercial facility,more » and estimate the corresponding commercial plant economic performance. To assemble the facility design, the following work was performed: (a) collection of Union Carbide's applicable background technology; (b) design, assembly, and operation of a small integrated silane-producing Process Development Unit (PDU); (c) analysis, testing, and comparison of two high-temperature methods for converting pure silane to silicon metal; and (d) determination of chemical reaction equilibria and kinetics, and vapor-liquid equilibria for chlorosilanes.« less

Responses of Saccharomyces cerevisiae Strains from Different Origins to Elevated Iron Concentrations

PubMed Central

Martínez-Garay, Carlos Andrés; de Llanos, Rosa; Romero, Antonia María; Martínez-Pastor, María Teresa

2016-01-01

Iron is an essential micronutrient for all eukaryotic organisms. However, the low solubility of ferric iron has tremendously increased the prevalence of iron deficiency anemia, especially in women and children, with dramatic consequences. Baker's yeast Saccharomyces cerevisiae is used as a model eukaryotic organism, a fermentative microorganism, and a feed supplement. In this report, we explore the genetic diversity of 123 wild and domestic strains of S. cerevisiae isolated from different geographical origins and sources to characterize how yeast cells respond to elevated iron concentrations in the environment. By using two different forms of iron, we selected and characterized both iron-sensitive and iron-resistant yeast strains. We observed that when the iron concentration in the medium increases, iron-sensitive strains accumulate iron more rapidly than iron-resistant isolates. We observed that, consistent with excess iron leading to oxidative stress, the redox state of iron-sensitive strains was more oxidized than that of iron-resistant strains. Growth assays in the presence of different oxidative reagents ruled out that this phenotype was due to alterations in the general oxidative stress protection machinery. It was noteworthy that iron-resistant strains were more sensitive to iron deficiency conditions than iron-sensitive strains, which suggests that adaptation to either high or low iron is detrimental for the opposite condition. An initial gene expression analysis suggested that alterations in iron homeostasis genes could contribute to the different responses of distant iron-sensitive and iron-resistant yeast strains to elevated environmental iron levels. PMID:26773083

Molecular-Scale Investigation with ESI-FT-ICR-MS on Fractionation of Dissolved Organic Matter Induced by Adsorption on Iron Oxyhydroxides.

PubMed

Lv, Jitao; Zhang, Shuzhen; Wang, Songshan; Luo, Lei; Cao, Dong; Christie, Peter

2016-03-01

Adsorption by minerals is a common geochemical process of dissolved organic matter (DOM) which may induce fractionation of DOM at the mineral-water interface. Here, we examine the molecular fractionation of DOM induced by adsorption onto three common iron oxyhydroxides using electrospray ionization coupled with Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). Ferrihydrite exhibited higher affinity to DOM and induced more pronounced molecular fractionation of DOM than did goethite or lepidocrocite. High molecular weight (>500 Da) compounds and compounds high in unsaturation or rich in oxygen including polycyclic aromatics, polyphenols and carboxylic compounds had higher affinity to iron oxyhydroxides and especially to ferrihydrite. Low molecular weight compounds and compounds low in unsaturation or containing few oxygenated groups (mainly alcohols and ethers) were preferentially maintained in solution. This study confirms that the double bond equivalence and the number of oxygen atoms are valuable parameters indicating the selective fractionation of DOM at mineral and water interfaces. The results of this study provide important information for further understanding the behavior of DOM in the natural environment.

Mathematical modeling of the dynamic storage of iron in ferritin

PubMed Central

2010-01-01

Background Iron is essential for the maintenance of basic cellular processes. In the regulation of its cellular levels, ferritin acts as the main intracellular iron storage protein. In this work we present a mathematical model for the dynamics of iron storage in ferritin during the process of intestinal iron absorption. A set of differential equations were established considering kinetic expressions for the main reactions and mass balances for ferritin, iron and a discrete population of ferritin species defined by their respective iron content. Results Simulation results showing the evolution of ferritin iron content following a pulse of iron were compared with experimental data for ferritin iron distribution obtained with purified ferritin incubated in vitro with different iron levels. Distinctive features observed experimentally were successfully captured by the model, namely the distribution pattern of iron into ferritin protein nanocages with different iron content and the role of ferritin as a controller of the cytosolic labile iron pool (cLIP). Ferritin stabilizes the cLIP for a wide range of total intracellular iron concentrations, but the model predicts an exponential increment of the cLIP at an iron content > 2,500 Fe/ferritin protein cage, when the storage capacity of ferritin is exceeded. Conclusions The results presented support the role of ferritin as an iron buffer in a cellular system. Moreover, the model predicts desirable characteristics for a buffer protein such as effective removal of excess iron, which keeps intracellular cLIP levels approximately constant even when large perturbations are introduced, and a freely available source of iron under iron starvation. In addition, the simulated dynamics of the iron removal process are extremely fast, with ferritin acting as a first defense against dangerous iron fluctuations and providing the time required by the cell to activate slower transcriptional regulation mechanisms and adapt to iron stress conditions. In summary, the model captures the complexity of the iron-ferritin equilibrium, and can be used for further theoretical exploration of the role of ferritin in the regulation of intracellular labile iron levels and, in particular, as a relevant regulator of transepithelial iron transport during the process of intestinal iron absorption. PMID:21047430

Mathematical modeling of the dynamic storage of iron in ferritin.

PubMed

Salgado, J Cristian; Olivera-Nappa, Alvaro; Gerdtzen, Ziomara P; Tapia, Victoria; Theil, Elizabeth C; Conca, Carlos; Nuñez, Marco T

2010-11-03

Iron is essential for the maintenance of basic cellular processes. In the regulation of its cellular levels, ferritin acts as the main intracellular iron storage protein. In this work we present a mathematical model for the dynamics of iron storage in ferritin during the process of intestinal iron absorption. A set of differential equations were established considering kinetic expressions for the main reactions and mass balances for ferritin, iron and a discrete population of ferritin species defined by their respective iron content. Simulation results showing the evolution of ferritin iron content following a pulse of iron were compared with experimental data for ferritin iron distribution obtained with purified ferritin incubated in vitro with different iron levels. Distinctive features observed experimentally were successfully captured by the model, namely the distribution pattern of iron into ferritin protein nanocages with different iron content and the role of ferritin as a controller of the cytosolic labile iron pool (cLIP). Ferritin stabilizes the cLIP for a wide range of total intracellular iron concentrations, but the model predicts an exponential increment of the cLIP at an iron content > 2,500 Fe/ferritin protein cage, when the storage capacity of ferritin is exceeded. The results presented support the role of ferritin as an iron buffer in a cellular system. Moreover, the model predicts desirable characteristics for a buffer protein such as effective removal of excess iron, which keeps intracellular cLIP levels approximately constant even when large perturbations are introduced, and a freely available source of iron under iron starvation. In addition, the simulated dynamics of the iron removal process are extremely fast, with ferritin acting as a first defense against dangerous iron fluctuations and providing the time required by the cell to activate slower transcriptional regulation mechanisms and adapt to iron stress conditions. In summary, the model captures the complexity of the iron-ferritin equilibrium, and can be used for further theoretical exploration of the role of ferritin in the regulation of intracellular labile iron levels and, in particular, as a relevant regulator of transepithelial iron transport during the process of intestinal iron absorption.

Magnetic susceptibility as a proxy for the hydrobiogeochemical cycling of iron within the water table fluctuation zone at hydrocarbon contaminated sites

NASA Astrophysics Data System (ADS)

Atekwana, E. A.; Enright, A.; Atekwana, E. A.; Beaver, C. L.; Rossbach, S.; Slater, L. D.; Ntarlagiannis, D.

2016-12-01

Sharp redox gradients are indicative of enhanced biogeochemical activity and occur at or near the water table. Hydrologic forcing drives changes in redox state and oxygen levels, enhancing the elemental cycling of metals, and coupling different biogeochemical cycles. These coupled hydrobiogeochemical cycles are often difficult to study in the field using geochemical and microbial proxies because of direct sampling limitations, the costs associated with these techniques, and because the dynamic nature of these processes complicates the interpretation of single time point measurements, which may not give accurate representations of prevailing conditions. Geophysical techniques can provide both the spatial and temporal resolution needed to elucidate these processes. Here we investigated the use of magnetic susceptibility (c) as a viable proxy for understanding the biogeochemical cycling of iron at several hydrocarbon contaminated sites where active intrinsic bioremediation is occurring. We performed borehole c logging using a Bartington c probe in the field as well as made c measurements on core samples retrieved from the field sites. Our results show the following: (1) in both sulfate-rich and sulfate-poor aquifers, excursions in c are coincident with zones of free product contamination and are limited to the water table fluctuation (smear) zone; (2) c values within the free product plume and contamination source zones are higher compared to values within the dissolved product plume; (3) high c coincides with zones of elevated Fe (II) and Fe (III) concentrations extracted from aquifer solids; and (4) the mixed valence magnetite and greigite were the dominant magnetic minerals. The c excursions are limited to the water table fluctuation zones because fluctuating water level conditions are hot beds for microbial activity due to the steep hydrocarbon and nutrients and consequently redox gradients. High water levels during periods of recharge favor anaerobic conditions enhancing iron reduction, while low water conditions during drought periods favor iron oxidation due to increased oxygen penetration. Such conditions favor mixed valent iron minerals such as magnetite and greigite. We conclude that c measurements are a low cost, rapid monitoring tool for assessing the elemental cycling of iron.

Process for the synthesis of iron powder

DOEpatents

Not Available

1982-03-06

A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

Process for the synthesis of iron powder

DOEpatents

Welbon, William W.

1983-01-01

A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

A highly stretchable autonomous self-healing elastomer

NASA Astrophysics Data System (ADS)

Li, Cheng-Hui; Wang, Chao; Keplinger, Christoph; Zuo, Jing-Lin; Jin, Lihua; Sun, Yang; Zheng, Peng; Cao, Yi; Lissel, Franziska; Linder, Christian; You, Xiao-Zeng; Bao, Zhenan

2016-06-01

It is a challenge to synthesize materials that possess the properties of biological muscles—strong, elastic and capable of self-healing. Herein we report a network of poly(dimethylsiloxane) polymer chains crosslinked by coordination complexes that combines high stretchability, high dielectric strength, autonomous self-healing and mechanical actuation. The healing process can take place at a temperature as low as -20 °C and is not significantly affected by surface ageing and moisture. The crosslinking complexes used consist of 2,6-pyridinedicarboxamide ligands that coordinate to Fe(III) centres through three different interactions: a strong pyridyl-iron one, and two weaker carboxamido-iron ones through both the nitrogen and oxygen atoms of the carboxamide groups. As a result, the iron-ligand bonds can readily break and re-form while the iron centres still remain attached to the ligands through the stronger interaction with the pyridyl ring, which enables reversible unfolding and refolding of the chains. We hypothesize that this behaviour supports the high stretchability and self-healing capability of the material.

Gold Leaching Characteristics and Intensification of a High S and As-Bearing Gold Concentrate

NASA Astrophysics Data System (ADS)

Yang, Yong-bin; Liu, Xiao-liang; Jiang, Tao; Li, Qian; Xu, Bin; Zhang, Yan

Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

Feasibility of co-reduction roasting of a saprolitic laterite ore and waste red mud

NASA Astrophysics Data System (ADS)

Wang, Xiao-ping; Sun, Ti-chang; Kou, Jue; Li, Zhao-chun; Tian, Yu

2018-06-01

Large scale utilization is still an urgent problem for waste red mud with a high content of alkaline metal component in the future. Laterite ores especially the saprolitic laterite ore are one refractory nickel resource, the nickel and iron of which can be effectively recovered by direct reduction and magnetic separation. Alkaline metal salts were usually added to enhance reduction of laterite ores. The feasibility of co-reduction roasting of a saprolitic laterite ore and red mud was investigated. Results show that the red mud addition promoted the reduction of the saprolitic laterite ore and the iron ores in the red mud were co-reduced and recovered. By adding 35wt% red mud, the nickel grade and recovery were 4.90wt% and 95.25wt%, and the corresponding iron grade and total recovery were 71.00wt% and 93.77wt%, respectively. The X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive spectroscopy (SEM-EDS) analysis results revealed that red mud addition was helpful to increase the liquid phase and ferronickel grain growth. The chemical compositions "CaO and Na2O" in the red mud replaced FeO to react with SiO2 and MgSiO3 to form augite.

Atmospheric Processing and Iron Mobilization of Ilmenite: Iron-Containing Ternary Oxide in Mineral Dust Aerosol.

PubMed

Hettiarachchi, Eshani; Hurab, Omar; Rubasinghege, Gayan

2018-02-08

Over the last several decades, iron has been identified as a limiting nutrient in about half of the world's oceans. Its most significant source is identified as deposited iron-containing mineral dust that has been processed during atmospheric transportation. The current work focuses on chemical and photochemical processing of iron-containing mineral dust particles in the presence of nitric acid, and an organic pollutant dimethyl sulfide under atmospherically relevant conditions. More importantly, ilmenite (FeTiO 3 ) is evaluated as a proxy for the iron-containing mineral dust. The presence of titanium in its lattice structure provides higher complexity to mimic mineral dust, yet it is simple enough to study reaction pathways and mechanisms. Here, spectroscopic methods are combined with dissolution measurements to investigate atmospheric processing of iron in mineral dust, with specific focus on particle mineralogy, particle size, and their environmental conditions (i.e., pH and solar flux). Our results indicate that the presence of titanium elemental composition enhances iron dissolution from mineral dust, at least by 2-fold comparison with its nontitanium-containing counterparts. The extent of iron dissolution and speciation is further influenced by the above factors. Thus, our work highlights these important, yet unconsidered, factors in the atmospheric processing of iron-containing mineral dust aerosol.

[Causes of iron deficiency in children].

PubMed

Olives, J-P

2017-05-01

Iron deficiency and iron deficiency anemia are common conditions worldwide affecting especially children. In developing countries, iron deficiency is caused by poor iron intake and parasitic infection. Poor iron intake linked to inadequate diets, low iron intestinal absorption, chronic blood losses and increased requirements are common causes in high-income countries. © 2017 Elsevier Masson SAS. Tous droits réservés.

Quantification of trace elements and speciation of iron in atmospheric particulate matter

NASA Astrophysics Data System (ADS)

Upadhyay, Nabin

Trace metal species play important roles in atmospheric redox processes and in the generation of oxidants in cloud systems. The chemical impact of these elements on atmospheric and cloud chemistry is dependent on their occurrence, solubility and speciation. First, analytical protocols have been developed to determine trace elements in particulate matter samples collected for carbonaceous analysis. The validated novel protocols were applied to the determination of trace elements in particulate samples collected in the remote marine atmosphere and urban areas in Arizona to study air pollution issues. The second part of this work investigates on solubility and speciation in environmental samples. A detailed study on the impact of the nature and strength of buffer solutions on solubility and speciation of iron lead to a robust protocol, allowing for comparative measurements in matrices representative of cloud water conditions. Application of this protocol to samples from different environments showed low iron solubility (less than 1%) in dust-impacted events and higher solubility (5%) in anthropogenically impacted urban samples. In most cases, Fe(II) was the dominant oxidation state in the soluble fraction of iron. The analytical protocol was then applied to investigate iron processing by fogs. Field observations showed that only a small fraction (1%) of iron was scavenged by fog droplets for which each of the soluble and insoluble fraction were similar. A coarse time resolution limited detailed insights into redox cycling within fog system. Overall results suggested that the major iron species in the droplets was Fe(1I) (80% of soluble iron). Finally, the occurrence and sources of emerging organic pollutants in the urban atmosphere were investigated. Synthetic musk species are ubiquitous in the urban environment (less than 5 ng m-3) and investigations at wastewater treatment plants showed that wastewater aeration basins emit a substantial amount of these species to the atmosphere.