Relative Amounts Of Iron Research Articles

Preparation of magnetic carbon nanofibers derived from bacterial cellulose alloyed with magnetic fluid

Magnetic carbon nanofibers (CNFs) carbonized at different temperatures were prepared from bacterial cellulose (BC) alloyed with magnetic fluid (MF) or Fe3O4 powder to facilitate the efficient use of biomass resources. The CNFs alloyed with magnetic nanoparticles demonstrated high saturation magnetizations and coercivities up to a carbonization temperature of 800 °C. Iodine-treated BC alloyed with magnetic nanoparticles showed a substantial increase in the char yields with lower saturation magnetizations compared to the iodine-untreated BC. The analysis of X-ray diffraction results implies that the magnetic properties are related to the types and relative amounts of iron and iron-containing compounds, and the existence of amorphous magnetic nanoparticles in the CNFs. Scanning electron microscopy results indicated that the surfaces of the MF-alloyed CNFs possessed a fused fibrous texture with voids, and the magnetic CNFs without iodine treatment featured crystalline nanoparticles. The MF-alloyed CNFs with iodine treatment demonstrated the maximum surface area and pore volume, while the MF-alloyed CNFs without iodine treatment mainly contained mesopores.

Magnetic properties of magnetic glass-like carbon prepared from furan resin alloyed with magnetic fluid

Magnetic glass-like carbons that were heat-treated at different temperatures or were filled with different magnetic nanoparticle contents were prepared from furan resin alloyed with magnetic fluid (MF) or Fe3O4 powder in their liquid-phase states during mixing. Compared to the Fe3O4 powder-alloyed carbon, the MF-alloyed carbon has highly dispersed the nanoparticles, and has the excellent saturation magnetization and coercivity. It is implied that saturation magnetizations are related to changes in the types of phases for the nanoparticles and the relative intensities of X-ray diffraction peaks for iron and iron-containing compounds in the carbons. Additionally, the coercivities are possibly affected by the size and crystallinity of the nanoparticles, the relative amounts of iron, and the existence of amorphous compounds on the carbon surfaces.

Chemical analyses of extremely degraded wood using analytical pyrolysis and inductively coupled plasma atomic emission spectroscopy

Alum-treated archaeological woods from the Oseberg collection, excavated and treated in the early 1900s demonstrate an extreme deterioration, only discovered in the past decade.This research was aimed at understanding the characteristics of the naturally aged material through chemical analyses of both organic and inorganic components, in order to provide information for the preservation/conservation of these precious objects.Analytical pyrolysis-gas chromatography/mass spectrometry with in situ silylation using hexamethyldisilazane (Py(HMDS)-GC/MS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were used to investigate a set of samples of alum-treated archaeological wood and untreated archaeological wood. Sound woods of the same species were also analysed in order to compare the results.Results from Py(HMDS)-GC/MS analyses of alum-treated woods from Oseberg showed an extreme depletion of carbohydrates and a highly deteriorated lignin network. The majority of the lignin had undergone oxidation reactions, illustrated by high relative amounts of acidic pyrolysis products. In particular, p-hydroxy-benzoic acid was detected for the first time as a degradation product of archaeological wood. Results from ICP-AES showed variable concentrations of aluminium and potassium from the alum treatment, as well as iron, copper, zinc and calcium. The extent of oxidation observed by Py(HMDS)-GC/MS appeared to correlate with relative amounts of iron and calcium in the samples, which may suggest that degradation promoted by iron compounds is inhibited in the presence of calcium compounds.The results obtained for a sample of archaeological wood treated with alum salts five years ago showed that chemical deterioration of lignin had already begun, mainly involving depolymerisation reactions, though only a slight increase in oxidation was evident.In addition to increased insight into potential deterioration reactions, occurring in a complex material such as alum-treated archaeological wood, it was possible to relate the degree of chemical degradation of the Oseberg woods to their visual condition (observed with the naked eye).

Effects of Phytases and Dehulling Treatments on In Vitro Iron and Zinc Bioavailability in Faba Bean (Vicia faba L.) Flour and Legume Fractions

In vitro digestions were performed on faba bean flours with decreased phytate contents and on 2 dephytinized or nondephytinized faba bean fractions, a dehulled faba bean fraction, and a hull fraction with low and high fiber and tannin contents, respectively. In vitro bioavailability iron and zinc was defined as the relative amount of iron and zinc that became soluble after enzymatic treatment. Faba bean samples were sequentially digested with enzymes, including amylase, pepsin, pancreatin, and bile, under certain conditions following the enzymatic degradation procedure. Iron and zinc in vitro bioavailability of whole faba bean flours were significantly improved by phytate degradation, even if the phytate were not all degraded. Total dephytinization of dehulled faba bean led to an obvious increase in iron and zinc in vitro bioavailability, but that of hulls had no effect on either iron or zinc in vitro bioavailability. Fibers and tannins other than phytate are more important in chelating a high proportion of iron and zinc in faba bean hulls.

Increased Hepcidin Expression in Mice Affected by β-Thalassemia Reduces Iron Overload with No Effect on Anemia

Iron overload is a potentially lethal complication of β-thalassemia, affecting the structure and function of many organs. Hepcidin (Hamp) is a peptide of hepatic origin, which regulates iron metabolism by triggering the degradation of ferroportin (Fpn), an iron-transport protein localized on absorptive enterocytes, hepatocytes and macrophages. We showed that while iron overload increases with time in mice with thalassemia intermedia (th3/+), Hamp1 is expressed at a low level relative to the amount of body iron (Gardenghi et al. Blood. 2007 109:5027–35). Thalassemic patients exhibit a similar picture, having low levels of urinary HAMP. We hypothesize that th3/+ mice absorb more iron than they need for erythropoiesis and that reducing their iron intake has no effect on anemia. Accordingly, we postulated that selectively increasing the Hamp concentration might be therapeutic, limiting iron overload by reducing the amount of Fpn. However, increasing Hamp might also impair erythropoiesis by preventing release of iron from macrophages. We utilized different strategies to investigate the effects of increased Hamp on iron overload and erythropoiesis. First, we generated animals over expressing Hamp1, both wt (Tg-Hamp1; N=8) (Roy et al. Blood. 2007 109:4038) and th3/+ mice (Tg-Hamp1/th3; N=8). The animals were fed a defined iron sufficient diet (35 ppm) for 1 and 5 mo and compared with wt and th3/+ mice fed diets containing 2.5, 35 and 200 ppm of iron; N>5 per group). The 200-ppm diet was standard rodent chow containing approximately 10 times more iron than physiologically required. At 5 mo, mice fed the 35- and 200-ppm iron diets had similar organ iron contents and erythropoietic parameters. The 2.5-ppm diet induced a progressive anemia in wt mice (Hgb: 14.6 ± 0.7 g/dL and 8.7 ± 3.0 g/dL at 1 and 5 mo, respectively). In contrast, the same diet did not worsen the anemia in th3/+ animals, confirming our first hypothesis (Hgb: 8.2 ± 1.2 g/dL vs 8.2 ± 1.7 g/dL at 1 and 5 mo, respectively). In th3/+ mice, the combined amount of iron in the liver and spleen decreased over time and after 5 mo was 10 times less than at the beginning of the 2.5-ppm diet. The relative amount of iron in the liver was reduced and that in the spleen increased, indicating mobilization of iron from storage to erythropoietic tissues. At 1 mo, Tg-Hamp1 mice showed mild anemia (Hgb: 10.6 ± 2.2 g/dL vs 13.6 ± 1.2 g/dL), and a greater number of immature erythroid progenitor cells in the spleen, compared to wt control mice. However, Tg-Hamp1/th3 mice did not have significant changes in hematological values compared to control th3/+ animals. The total iron content of the liver was decreased in both Tg-Hamp1 (59 ± 18 ug vs 145 ± 25 ug in wt controls) and Tg-Hamp1/th3 mice (156 ± 91 ug vs 264 ± 18 ug in th3/+ controls), while no significant changes in iron content were detected in the spleen. These data showed that over expression of Hamp1 in Tg- Hamp1/th3 mice could reduce tissue iron overload with no effect on anemia. A second strategy to increase the Hamp level involved direct i.v. injection of synthetic Hamp25 peptide (50 ug) into wt and th3/+ mice (N=6) for 14 days. Our data indicate that Hamp administration decreases the iron level in the serum, compared to animals injected with PBS, without any effect on anemia. Quantitative real-time PCR analysis on the liver of injected mice also revealed down-regulation of endogenous Hamp1 expression after Hamp25 administration. Organ iron analysis is in progress. Third, we generated lentiviral vectors where a synthetic murine transthyretin (TTR) promoter specifically drives Hamp1 cDNA expression in the hepatocytes of 3-day-old pups using micro injection of the liver. The advantage of this approach is that the liver of pups is small, visible through the skin, and the liver cells are proliferating, thereby making them more permissive to transduction than adult cells. Injection of a control vector expressing GFP driven by the TTR promoter was used to test the efficiency of the technique in wt mice (N=5). We observed a high level of GFP expression for up to 3 mo, while animals injected with PBS (N=5) were negative. Injection of wt and th3/+ mice with a lentiviral vector expressing Hamp1 is in progress. In conclusion, these studies are expected to contribute to the development of new pharmacological approaches to the treatment of abnormal iron absorption in β-thalassemia and related disorders.

Comparative study of the photocatalytic performance of boron–iron Co-doped and boron-doped TiO 2 nanoparticles

A series of nanosized boron-doped and boron–iron co-doped anatase TiO 2 represented as B x ,Fe y -TiO 2 ( x = 1, 3, 5, y = 0, 0.5, 1, 3, 5 in wt%) were synthesized by a modified sol–gel method, and characterized by various spectroscopic and analytical techniques. The presence of boron and/or iron causes a red shift in the absorption band of TiO 2. The B x ,Fe y -TiO 2 systems are very effective catalysts for the degradation of toluene under UV or visible light. All reactions follow pseudo-first-order kinetics with the rate being a function of either the dopants or the light source (UV or visible light). The relative quantity and most importantly the position occupied by dopant were found to be the crucial factors in co-doping with respect to the properties and activity of the final product. In general, boron-doping enhances the reactivity while iron-doping works in an opposite manner, thus to show the following order of reactivity regardless of the light source: B x -TiO 2 > TiO 2 > B x ,Fe y -TiO 2. Under the visible light, however, a reversal in this trend is made depending on the relative amount of iron. Thus, for instance, when y ≤ 5, the trend becomes as follows: B x -TiO 2 > B x ,Fe y -TiO 2 > TiO 2.

Characterization of Emeralds From a Historical Deposit: Byrud (Eidsvoll), Norway

An emerald deposit at Byrud, in southern Norway, yielded significant quantities of crystals and gem rough in the late 19th and early 20th centuries. Complex multiphase inclusions in the emeralds consist of water, gaseous methane, halite, sylvite, calcite, and a sulfide assemblage (pyrrhotite, galena, and sphalerite). This sulfide assemblage makes it easy to distinguish Byrud emeralds from those from other localities with a binocular microscope. The chemical composition of Byrud emeralds is also characteristic: They are colored mostly by vanadium (up to 1 wt.% V2O3), and contain low sodium and magnesium (0.1 wt.% oxide or less). Moreover, the relative amounts of iron, magnesium, chromium, rubidium, and cesium appear to be diagnostic. Infrared absorption spectra show that they contain little water. Emeralds from the Byrud deposit are still occasionally recovered by hobbyist collectors from the mine dumps.

Ferritin: a novel mechanism for delivery of iron to the brain and other organs

Traditionally, transferrin has been considered the primary mechanism for cellular iron delivery, despite suggestive evidence for additional iron delivery mechanisms. In this study we examined ferritin, considered an iron storage protein, as a possible delivery protein. Ferritin consists of H- and L-subunits, and we demonstrated iron uptake by ferritin into multiple organs and that the uptake of iron is greater when the iron is delivered via H-ferritin compared with L-ferritin. The delivery of iron via H-ferritin but not L-ferritin was significantly decreased in mice with compromised iron storage compared with control, indicating that a feedback mechanism exists for H-ferritin iron delivery. To further evaluate the mechanism of ferritin iron delivery into the brain, we used a cell culture model of the blood-brain barrier to demonstrate that ferritin is transported across endothelial cells. There are receptors that prefer H-ferritin on the endothelial cells in culture and on rat brain microvasculature. These studies identify H-ferritin as an iron transport protein and suggest the presence of an H-ferritin receptor for mediating iron delivery. The relative amount of iron that could be delivered via H-ferritin could make this protein a predominant player in cellular iron delivery.

Electrooxidation of gold-bearing sulfide concentrate

Gold losses in the cyanidation of refractory ores are mainly due to the presence of sulfide and carbonaceous materials. Sulfide minerals in the ore can be oxidized by hypochlorite generated electrochemically in the leaching reactor. The electrooxidation of a gold-bearing sulfide concentrate that contains pyrite, pyrrhotite and arsenopyrite was investigated in an electrochemical cell with 10% (by weight) NaCI electrolyte. The relative amount of iron dissolved by the oxidation of sulfide minerals increased with the duration of the test under constant applied current and leveled off at about 80% after 8 hours. Increasing the pulp density increased the current efficiency and the total amount of material oxidized. Cyanidation tests after 38% iron removal by electrooxidation resulted in a gold extraction increase of approximately 29% and a cyanide consumption decrease of about 31%.

Synthesis, Self-Assembly, and Magnetic Properties of FexCoyPt100-x-y Nanoparticles

FexCoyPt100-x-y alloy nanoparticles were prepared by the simultaneous reduction of cobalt acetylacetonate and platinum acetylacetonate and the thermal decomposition of iron pentacarbonyl. The relative amounts of iron, cobalt, and platinum in the particles depended on the amount of iron, cobalt and platinum charged to the reaction. As prepared, the particles were superparamagnetic and had a distorted fcc structure. The average particle diameter was 3.5 nm and the size distribution was very narrow. The particles could be dispersed in hydrocarbon solvents and formed films consisting of hexagonal close-packed particles on carbon-coated copper TEM grids. The films were sputter coated with amorphous carbon and then annealed at temperatures ranging from 550 to 700 °C to transform the particles to the tetragonal (L10) phase. The coercivity of the annealed films increased with increasing annealing temperature. For films with a similar degree of transformation to the tetragonal phase, increasing the cobalt content ...

Mössbauer spectroscopy study of the chemical state of iron in Danish Mesozoic sediments

The chemical state of iron in sediments from six wells in the Danish North Sea and the Danish land area has been studied by use of Mössbauer spectroscopy. It was found that iron was mainly present in pyrite, clay minerals and the carbonates siderite and ankerite. The relative amounts of iron in different minerals have been determined as a function of depth in the wells. A comparison of the results with available data for source rock maturity suggests that there may be a correlation between the presence of ankerite and the formation of oil and gas in the sediments.

Ferromagnesian silicate abundances in bronzite chondrites as determined by the Mössbauer effect

The Mössbauer effect in 57Fe was used to investigate iron minerals in meteorites. The ratio of olivine iron to pyroxene iron (calculated from the absorption intensities and the recoilless fractions) was found to be 1.6 ± 0.2 for the bronzite chondrites Collescipoli, Ochansk, and Oakley. The relative amounts of iron in olivine and pyroxene may be combined with the electron microprobe analyses of iron and magnesium in the separate minerals to obtain the number of formula units of pyroxene relative to olivine in an unseparated meteorite sample. The similar abundance ratios of pyroxene to olivine indicate that these meteorites were derived from a common parent ferromagnesian silicate reservoir. For each meteorite, the FeO content of the olivine-pyroxene system is given as calculated from the MgO content of the chemical analysis, the ratio of magnesium to iron in each silicate, and the relative amounts of iron in olivine and pyroxene.

Mössbauer analysis of iron in stone meteorites

The absorption of resonant gamma rays by Fe 57 nuclei in stone meteorites produces patterns characteristic of the various iron compounds in the meteorite. By comparison with absorption patterns of terrestrial reference minerals, the meteoritic compounds may be identified and the relative amounts of iron in each mineral determined. The minerals identified in the Plainview meteorite were olivine and pyroxene (ferromagnesian silicates), troilite (a sulfide), and kamacite (an iron-nickel alloy). The absorption patterns of the Holbrook and Johnstown meteorites were also investigated.

Factors Affecting the Susceptibility of Multivitamin Mineral Milk to Oxidation

Summary The flavor of multivitamin mineral (MVM) milk was not affected when it was processed in a conventional HTST pasteurizer-homogenizer system. However, when it was subjected to a steam-vacuum treatment, in addition to pasteurization and homogenization, an oxidized flavor developed. The off-flavor developed regardless of whether the MVM preparation was added before or after processing. This indicates that alteration of the milk, rather than the MVM preparation, was involved in the development of the oxidized flavor. It was observed that homogenized-treated milk from another milk plant did not develop an oxidized flavor when fortified with MVM mix. Results indicated that the difference in susceptibility between the homogenized-treated milk from the two plants was due to processing differences. The iron compound, ferric pyrophosphate soluble, was identified as the ingredient in the MVM preparation causing the oxidized flavor. Fortification of homogenized and homogenized-treated milks with ferric and ferrous compounds showed that both milks developed oxidized flavors when fortified with ferrous iron. However, the homogenized-treated milk was more susceptible than the homogenized milk when ferric iron was added. It was suggested that the difference in susceptibility between homogenized and homogenized-treated milk is a difference in the capacity of these milks to reduce ferric iron to the stronger pro-oxidant ferrous form. Measurements of the relative amounts of iron reduced by these milks substantiate this explanation.