Decrease In Iron Content Research Articles

Kleberite, Fe3+Ti6O11(OH)5, a new ilmenite alteration product, from Königshain, northeast Germany

AbstractKleberite, ideally Fe3+Ti6O11(OH)5, is a new mineral (IMA 2012-023) from Tertiary sands at Königshain, Saxony, northeast Germany. It is also found in heavy mineral sands from the Murray Basin, southeast Australia and at Kalimantan, Indonesia. It occurs as rounded anhedral to euhedral translucent grains, 0.04 0.3 mm across, which are generally red-brown, but grade to orange with decreasing iron content. Associated minerals include ilmenite, pseudorutile, 'leucoxene', tourmaline and spinel. The density measured by pycnometry is 3.28 g cm-3, which is lower than the calculated density of 3.91 g cm-3, due to intragrain porosity which is not penetrated by the immersion fluid. The intragrain pores, of median diameter 18 nm, are partially filled with impurity phases including kaolinite, diaspore and quartz. Kleberite grains have a uniaxial (–) character, but localized regions are weakly biaxial (–) with 2V close to zero. The mean refractive index, calculated from reflectance measurements, is 2.16(3). The mean empirical formula from electron-microprobe analyses of 15 Königshain kleberite grains is Fe3+1.01Mg0.06Ti6O11.2(OH)4.8[Al0.59Si0.31P0.04O1.60·1.8H2O], where the formula element in square brackets represents impurities in the pores. Kleberite forms over a compositional range with [Ti]/[Fe + Ti] atomic ratios from 0.8–0.9. It has monoclinic symmetry, P21/c, with a = 7.537(1), b = 4.5795(4), c = 9.885(1) Å , β = 131.02(1)°. The six strongest lines in the powder X-ray diffraction (XRD) pattern [listed as d in Å (I)] are as follows: 1.676(100), 2.170(82), 2.466(27), 1.423(22), 3.933(8), 2.764(9). The structure was refined by the Rietveld method on powder XRD data to Rp = 6.3, Rwp = 8.1, RB = 4.0. Kleberite is isostructural with tivanite; their structural formulae are [Ti4+3□][Ti4+3Fe3+]O11 (OH)5 and [Ti4+4][V3+4]O12(OH)4, respectively. Kleberite has dominant Ti4+ in place of V3+ in the M(2) metal-atom site. The related mineral pseudorutile, [Ti4][(Fe3+,Ti)4](O,OH)16, with Fe3+ > Ti4+ has dominant Fe3+ in this site. Kleberite grains from different localities commonly contain residual MgO-rich ferrian ilmenite. The chemical and physical relationships between the ilmenite and coexisting kleberite are used to evaluate different alteration mechanisms involving selective leaching of divalent oxides from ilmenite and pseudomorphic replacement reactions, respectively.

Altered transition metal homeostasis in mice following manganese injections for manganese-enhanced magnetic resonance imaging

In manganese-enhanced magnetic resonance imaging (MEMRI), the paramagnetic divalent ion of manganese (Mn(2+)) is injected into animals to generate tissue contrast, typically at much higher exposures than have been previously used in studies of Mn toxicity. Here we investigate the effect of these injections on the homeostasis of the transition metals iron and copper in mice to see if there are disruptions which should be considered in MEMRI studies. Manganese shares transport proteins with other transition metals including iron and copper, so it is possible that changes in manganese levels in tissue following injections of the metal may affect other metal levels too. This in turn may affect MRI contrast or the investigation of disease processes in the animal models being imaged. In this study, we measured manganese, iron, and copper concentrations in the blood, kidney, liver and in brain regions in mice treated with four injections of 30mg/kg MnCl(2) 4H(2)O (dry chemical weight/body weight)-a common dose used in MEMRI. In addition to the expected increases in manganese in tissues, we noted a statistically significant reduction in copper in the kidney and liver. Also, we noted a statistically significant decrease in concentration of iron in the thalamus of the brain. These findings suggest that the high doses of manganese injected in MEMRI studies can disrupt the homeostasis of other transition metals in mice.

Evolution of microstructure and mechanical properties in Cu–14%Fe alloy during severe cold rolling

Cu–14%Fe alloy was produced by vacuum arc remelting and casting in water-cooled mold with subsequent hot extrusion. It had fine grained microstructure with supersaturated solid solutions based on Cu and Fe phases. The alloy was subjected to cold sheet rolling with true strains up to 6.6. Microstructure was studied by SEM and TEM, specific attention was paid to chemical composition of individual phases—copper matrix and iron particles. After rolling very fine lamellar structure formed in copper matrix. Rolling also has resulted in decrease of iron content in matrix from 3.8% in initial condition to 1% after rolling with strain of 5.1 due to decomposition of supersaturated solid solution. At higher strain some deformation-induced mechanical alloying was observed, leading to local increase of iron content. Iron particles also were heavily refined; their average thickness after rolling with strain of 6.6 is about 30nm (according to TEM data). Several possible mechanisms of their refinement in addition to homogeneous plastic deformation are proposed. Strength of the alloy measured by tensile testing increased significantly after rolling. For example, ultimate tensile strength increased from 325MPa in initial condition to almost 1000MPa after rolling with strain of 6.6. Good correlation between mechanical strength and spacing between iron particles in accordance with Hall–Petch relationship was found.

Photocatalytic hydrogen production over CuGa2−xFexO4 spinel

Recovery of hydrogen from industrial H2S waste using spinel photocatalyst was studied. Spinel metal oxide photocatalysts (CuGa2−xFexO4 for x = 0.8, 0.6 and 0.4) were synthesized by ceramic route. They were loaded with 0.5 and 1 wt% noble metal oxide, RuO2. Their XRD pattern revealed a single phase cubic spinel crystalline structure for all the catalysts. SEM displayed small size cubic particles with the particle size decreasing with the decrease in iron content. 1 wt% RuO2 loaded CuGa1.6Fe0.4O4 decomposed H2S in aqueous 0.5 M KOH solution under visible light (λ ≥ 420 nm) irradiation and generated H2 to the tune of 10,045 μmol/h, giving rise to a high quantum efficiency of 21% at 510 nm.

Iron uptake and homeostasis related genes in potato cultivated in vitro under iron deficiency and overload

Potato is one of the most important staple food in the world because it is a good source of vitamin C, vitamin B6 but also an interesting source of minerals including mainly potassium, but also magnesium, phosphorus, manganese, zinc and iron to a lesser extent. The lack of iron constitutes the main form of micronutrient deficiency in the world, namely iron deficiency anemia, which strongly affects pregnant women and children from developing countries. Iron biofortification of major staple food such as potato is thus a crucial issue for populations from these countries. To better understand mechanisms leading to iron accumulation in potato, we followed in an invitro culture experiment, by qPCR, in the cultivar Désirée, the influence of media iron content on the expression of genes related to iron uptake, transport and homeostasis. As expected, plantlets grown in a low iron medium (1mgL(-1) FeNaEDTA) displayed a decreased iron content, a strong induction of iron deficiency-related genes and a decreased expression of ferritins. Inversely, plantlets grown in a high iron medium (120mgL(-1) FeNaEDTA) strongly accumulated iron in roots; however, no significant change in the expression of our set of genes was observed compared to control (40mgL(-1) FeNaEDTA).

G05 Alterations in iron content in the brain of Huntington disease mutation carriers in comparison with healthy control subjects

<h3>Background</h3> It has been hypothesised that changes in iron content in the brain may be involved in the pathogenesis of Huntington Disease (HD).^1–5 T*2-weighted imaging may be a useful measure to study iron distribution in the brain since a strong linear correlation between chemically determined iron concentration and magnetic susceptibility has been established, specially for grey matter structures.^{6 7} Increased iron content in the caudate, putamen and specially in the globus pallidus of HD patients and presymptomatic subjects has been described.^1–5 <h3>Aims</h3> To investigate the potential spatial variations in T*2 signal in cerebral structure in Huntington disease mutation carriers. <h3>Methods</h3> 77 mutation carriers (29 presymptomatic and 48 at early disease stages) and 73 age and gender matched controls underwent T*2 multiecho relaxometry on a 3 Tesla Siemens scanner (Abstract 12361-1 table 1). Six consecutive T*2- weighted gradient-echo whole-brain volumes were acquired using a segmented EPI sequence at different TEs: 6, 12, 20, 30, 45, 60 ms (TR: 5000, bandwidth: 1116 Hz/voxel, matrix size: 128 mm³; voxel size: 1.8 mm³). Image processing was performed combining FSL 4.0 and SPM8 running in Matlab 6.5. Artifacts in the susceptibility maps were avoided by using the first echo data to mask brain tissue. The statistical analysis of the susceptibility maps was carried by a two-sample t-test. The final results were corrected for multiple comparisons using a family wise error (FWE) rate correction set at p&lt;0.05. <h3>Results</h3> When compared with age and gender-matched control subjects, mutation carriers had increased iron levels in the globus pallidus/putamen bilaterally (p cluster: &lt;0.001 left; &lt;0.01 right; t: 7.41 left; 6.18 right). Furthermore, HD subjects had decreased iron content in occipital and posterior grey matter areas in comparison with control subjects (p cluster: &lt;0.001; t: 6.65). <h3>Conclusions</h3> The data suggest that iron alterations occur early in the HD process and have a role in the selective striatal degeneration underlying HD pathology. Prospective studies are needed to verify how increased iron levels are involved in HD pathogenesis. <h3>References</h3> 1. <b>Bartzokis G</b>, Lu PH, Tishler TA, <i>et al.</i> Myelin breakdown and iron changes in Huntington9s disease: pathogenesis and treatment implications. <i>Neurochem Res</i> 2007;<b>32</b>:1655–64. 2. <b>Bartzokis G</b>, Cummings J, Perlman S, <i>et al.</i> Increased basal ganglia iron levels in Huntington disease. <i>Arch Neurol</i> 1999;<b>56</b>:569–74. 3. <b>Rosas HD</b>, Chen YI, Doros G, <i>et al.</i> Alterations in brain transition metals in Huntington disease: an evolving and intricate story. <i>Arch Neurol</i> 2012. In press. 4. <b>Sánchez-Castañeda C</b>, Cherubini A, Elifani F, <i>et al.</i> Seeking huntington disease biomarkers by multimodal, cross-sectional basal ganglia imaging. <i>Hum Brain Mapp</i> 2012. In press. 5. <b>Vymazal J</b>, Klempír J, Jech R, <i>et al.</i> MR relaxometry in Huntington9s disease: correlation between imaging, genetic and clinical parameters. <i>J Neurol Sci</i> 2007;<b>263</b>:20–5. 6. <b>Cherubini A</b>, Péran P, Hagberg GE, <i>et al.</i> Characterisation of white matter fibre bundles with T2* relaxometry and diffusion tensor imaging. <i>Magn Reson Med</i> 2009b;<b>61</b>:1066–72. 7. <b>Langkammer C</b>, Schweser F, Krebs N, <i>et al.</i> Quantitative susceptibility mapping (QSM) as a means to measure brain iron? A post mortem validation study. <i>Neuroimage</i> 2012. In press.

Capacity of Wood Ash Filters to Remove Iron from Acid Mine Drainage: Assessment of Retention Mechanism

Acid mine drainage (AMD) with high iron concentrations can be a major challenge for passive treatment systems, particularly when sulphate reducing passive bioreactors (SRPBs) are used. The capacity of wood ash filters to act as a polishing step after SRPB treatment of a high-iron AMD (4,000 mg L−1 of Fe) was assessed. Five columns (1.7 L) with different mixtures of wood combustion ash and sand were investigated for their potential to remove metals from an SRPB effluent over 122 days. These materials had a high specific surface area (between 46 and 159 m² g−1), high organic carbon contents (between 12 and 32 %), and a high paste pH (up to 12.2). The Freundlich isotherm model reflects the observed iron sorption behavior on the material surface. Column study results indicate that the wood ash decreased iron concentrations for more than 100 days below 10 mg L−1 (99 % iron removal), mainly due to iron hydroxide precipitation and sorption. The risk of system clogging was negligible since the saturated hydraulic conductivity remained stable, between 5.0 × 10−3 and 3.1 × 10−2 cm s−1. Between 44 and 52 % of the sulphate was also removed due to gypsum precipitation.

Magnetic field induced order–order phase transition in magnetocaloric systems Mn2−xFexAs0.5P0.5 and MnFeAsyP1−y

An analysis is presented of experimental and theoretical results of the MnFeAsyP1−y (0.15≤y≤0.66) and Mn2−xFexAs0.5P0.5 (0.5≤x≤1.0) systems to identify main traits that underlie the mechanism of formation of different antiferromagnetic (AF) phases in the two systems. The discrepancy between the calculated from first principles and experimental values of the magnetic moment in the ferromagnetic phase with cation substitution in the system Mn2−xFexAs0.5P0.5 is due to the appearance of a canted magnetic structure. In this case, the emergence of an AF phase with decreasing iron concentration precedes a significant change in the electronic d-band filling. In the model of the spiral structure in the system of itinerant electrons it is shown that the stabilization of the AF phase with decreasing arsenic concentration, while maintaining the number of d-electrons, is a consequence of changes in the shape of the density of electronic states that occur with a decrease in unit-cell volume.

Production and Refining of Magnesium Metal from Turkey Originating Dolomite

AbstractIn this study crown magnesium produced from Turkish calcined dolomite by the Pigeon Process was refined and corrosion tests were applied.By using factsage thermodynamic program metalothermic reduction behavior of magnesium oxide and silicate formation structure during this reaction were investigated. After thermodynamic studies were completed, calcination of dolomite and it's metalothermic reduction at temperatures of 1473 K, 1523 K and within a vacuum (varied from 20 to 200 Pa) and refining of crown magnesium was studied. Different flux compositions consisting of MgClConsiderable amount of iron was transferred into the sludge phase and its amount decreased from 0.08% to 0.027%. This refined magnesium was suitable for the production of various magnesium alloys. As a result of decreasing iron content, minimum corrosion rate of refined magnesium was obtained 2.35 g

Role of the Dickeya dadantii Dps protein

During infection, the phytopathogenic enterobacterium Dickeya dadantii has to cope with iron-limiting conditions and the production of reactive oxygen species by plant cells. A tight control of the bacterial intracellular iron content is necessary for full virulence of D. dadantii: previous studies have shown that the ferritin FtnA and the bacterioferrtin Bfr, devoted to iron storage, contribute differentially to the virulence of this species. In this work, we investigated the role of the Dps miniferritin in iron homeostasis in D. dadantii. We constructed a Dps-deficient mutant by reverse genetics. This mutant grew like the wild-type stain under iron starvation and showed no decreased iron content. However, the dps mutant displayed an increased sensitivity to hydrogen peroxide in comparison to the wild-type strain. This hydrogen peroxide susceptibility only occurs when bacteria are in the stationary phase. Unlike the bfr and the ftnA mutants, the dps mutant is not affected in its pathogenicity on host plants. The dps gene expression is induced at the stationary phase of growth. The Sigma S transcriptional factor is necessary for this control. Furthermore, dps expression is positively regulated by the oxidative stress response regulator OxyR during the exponential growth phase, after hydrogen peroxide treatment. These results indicate that the Dps miniferritin from D. dadantii has a minor role in iron homeostasis, but is important in conferring tolerance to hydrogen peroxide and for survival of cells that enter the stationary phase of growth.

Protective effects of baicalin and quercetin on an iron-overloaded mouse: comparison of liver, kidney and heart tissues

Excessive accumulation of iron in the body can lead to organ injury. Some flavonoids which possess high affinity to iron can be used as iron chelators for curing iron overload diseases such as haemochromatosis. In this article, the effects of baicalin and quercetin on different mouse tissues (liver, kidney and heart) afflicted with iron overload-induced injury were studied. It was found that after administration of 500 mg kg−1 iron dextran for 45 days, the degree of oxidative injury in the three organs was different. When iron dextran-induced iron-overloaded mice were fed a diet containing baicalin or quercetin (1% w/w), both flavonoids showed significant effects in suppressing iron overload-induced injury. The efficiencies of both flavonoids on different tissues varied. Both flavonoids caused a significant decrease of iron content in liver and kidney tissues but not in the heart, whereas the flavonoids were more efficient in inhibiting the increase of carbonyl content and the thiobarbituric acid reactive substance levels in heart tissues. The results indicate that the protective effects of baicalin and quercetin on different tissues of iron-overloaded mice are different.

Switching effects of electrode polarity and introduction direction of reagents in electrokinetic-Fenton process with anionic surfactant for remediating iron-rich soil contaminated with phenanthrene

This study investigated effective operating method of enhanced electrokinetic-Fenton (EK-Fenton) process with anionic surfactant to remediate contaminated iron-rich clayey soil with phenanthrene, which had soil properties being frequently in contaminated sites. Introduction of 30 mM SDS as H 2O 2 stabilizer improved not only H 2O 2 stability but also degradation of phenanthrene compared to experiment without SDS. However, electrical potential drop in regions near cathode terminated electro-osmotic flow, and then phenanthrene in region near cathode kept initial concentration before switching of the electrodes polarities and introduction direction of reagents. After the polarity of the electrodes and introduction direction of reagents were switched, electro-osmotic flow was re-generated with re-distribution of electrical potential and electrical current. Furthermore, after switching electrode, decrease of iron concentration and pH in the soil specimen near cathode before switching electrode generated decrease of H 2O 2 decomposition rate. Therefore, H 2O 2 could be introduced in the cathode regions before switching the polarity of the electrodes and introduction direction of reagents. Furthermore, residual phenanthrene was degraded homogeneously after switching of the electrodes polarity and introduction direction of reagents, and then about 70% phenanthrene could be degraded.

Effect of iron content on electrical conductivity of ferropericlase with implications for the spin transition pressure

[1] The pressure-induced electronic spin transition of iron in ferropericlase was investigated as a function of iron content in ferropericlase by in situ electrical conductivity measurement. The electrical conductivity of ferropericlase, (Mg1-x,Fex)O (x = 0.07, 0.10, 0.13, 0.17, 0.24), was measured up to 53 GPa and 600 K using the Kawai-type multianvil apparatus equipped with sintered diamond anvils. At pressures up to 25 GPa, the electrical conductivity of ferropericlase generally increases with increasing pressure, and both the activation energy and activation volume of ferropericlase decrease with increasing iron content. For the samples with x = 0.07 and 0.10, the electrical conductivity shows a slight initial decrease and becomes constant between 25 and 40 GPa, upon which it increases slightly as the pressure increases. For the samples with higher iron content, the electrical conductivity constantly increases with pressure over the investigated pressure range. If these changes in the electrical conductivity are due to the isosymmetric high- to low-spin transition of iron in ferropericlase, this conductivity change suggests that the spin transition pressure significantly decreases with decreasing iron content in ferropericlase. Because the amount of iron in ferropericlase that coexists with the Al-bearing perovskite seems to be less than that in the Al-free perovskite, the influence of the iron partitioning between perovskite and ferropericlase by the spin transition appears in a pressure range of about 30–40 GPa in the lower mantle of the Earth.

Profile of altered brain iron acquisition in restless legs syndrome

Restless legs syndrome is a neurological disorder characterized by an urgency to move the legs during periods of rest. Data from a variety of sources provide a compelling argument that the amount of iron in the brain is lower in individuals with restless legs syndrome compared with neurologically normal individuals. Moreover, a significant percentage of patients with restless legs syndrome are responsive to intravenous iron therapy. The mechanism underlying the decreased iron concentrations in restless legs syndrome brains is unknown. We hypothesize that the source of the brain iron deficit is at the blood-brain interface. Thus we analysed the expression of iron management proteins in the epithelial cells of the choroid plexus and the brain microvasculature in post-mortem tissues. The choroid plexus, obtained at autopsy, from 18 neurologically normal controls and 14 individuals who had primary restless legs syndrome was subjected to histochemical staining for iron and immunostaining for iron management proteins. Iron and heavy chain ferritin staining was reduced in the epithelial cells of choroid plexus in restless legs syndrome. Divalent metal transporter, ferroportin, transferrin and its receptor were upregulated in the choroid plexus in restless legs syndrome. Microvessels were isolated from the motor cortex of 11 restless legs syndrome and 14 control brains obtained at autopsy and quantitative immunoblot analyses was performed. Expression of heavy chain ferritin, transferrin and its receptor in the microvessels from restless legs syndrome was significantly decreased compared with the controls but divalent metal protein 1, ferroportin, prohepcidin, mitochondrial ferritin and light-chain ferritin remained unchanged. The presence of an iron regulatory protein was demonstrated in the brain microvasculature and the activity of this protein is decreased in restless legs syndrome; a finding similar to our earlier report in neuromelanin cells from the substantia nigra of restless legs syndrome brains. This study reveals that there are alterations in the iron management protein profile in restless legs syndrome compared with controls at the site of blood-brain interface suggesting fundamental differences in brain iron acquisition in individuals with restless legs syndrome. Furthermore, the decrease in transferrin receptor expression in the microvasculature in the presence of relative brain iron deficiency reported in restless legs syndrome brains may underlie the problems associated with brain iron acquisition in restless legs syndrome. The consistent finding of loss of iron regulatory protein activity in restless legs syndrome brain tissue further implicates this protein as a factor in the underlying cause of the iron deficiency in the restless legs syndrome brain. The data herein provide evidence for regulation of iron uptake and storage within brain microvessels that challenge the existing paradigm that the blood-brain barrier is merely a transport system.

Changes in serum iron concentration and hepatic enzyme activities in cattle infected with Theileria annulata and Babesia bigemina

Analyses for alanine aminotransferase, aspartate aminotransferase (AST), alkaline phosphatase (ALP) activities, and iron concentration were carried out in infected and uninfected cattle in order to determine the degree of hepatic damage and blood iron status caused by Theileria annulata and Babesia bigemina. Blood samples from 30 infected and 20 uninfected cattle with T. annulata and also from 40 infected and 20 uninfected cattle with B. bigemina were taken. The biochemical analyses revealed increased serum AST and ALP activities in infected cattle with T. annulata and B. bigemina compared with uninfected cattle (P < 0.05). Significant decreases in iron concentration were observed in cattle infected with T. annulata and B. bigemina when compared with uninfected cattle (P < 0.05) although the level of serum iron concentration in infected cattle was within the normal reference values for cattle. It was concluded that iron deficiency anemia is not an important factor in T. annulata- and even in B. bigemina-infected cattle with severe intravascular hemolysis. The increased activities of serum enzymes indicated the hepatic injuries associated with infection with T. annulata and B. bigemina.

Growth promotion and a decrease of oxidative stress in maize seedlings by a combination of geomagnetic and weak electromagnetic fields

In the present study, we hypothesized that an appropriate combination of a geomagnetic field (as a static field) and an alternative magnetic field may result in the promotion of maize seedling growth by an alleviation of an excess production of reactive oxygen species. First, we determined the applicable range of frequencies by theoretical calculations, and a combined magnetic field was designed. The seeds were germinated in the magnetic field for 4 days, and the seedlings were allowed to grow in a nutrient solution for another 4 days. The magnetic field-treated maize seeds produced seedlings with a faster growth rate than the control seeds. The activity of superoxide dismutase in the magnetic field-treated seedlings was lower, while the total antioxidant capacity of these seedlings was higher than that of the control group. The maintenance of membrane integrity and a decrease of iron content in the magnetic field-treated seedlings suggest that a combination of both static and alternative magnetic fields promotes the growth of the plants by lowering iron absorption, a reduction in the Fenton chemistry, and lowering the risk of oxidative burst.

Iron Oxide Nanoparticles Embedded onto 3D Mesochannels of KIT‐6 with Different Pore Diameters and Their Excellent Magnetic Properties

Here, we report the results of our detailed study on the fabrication of iron oxide magnetic nanoparticles confined in mesoporous silica KIT-6 with a 3D structure and large, tunable pore diameters. It was confirmed by XRD, nitrogen adsorption, high-resolution (HR) TEM, and magnetic measurements that highly dispersed iron oxide nanoparticles are occupied inside the mesochannels of KIT-6. We also demonstrated that the size of the iron oxide nanoparticle can be controlled by simply changing the pore diameter of the KIT-6 and the weight percentage of the iron oxide nanoparticles. The effect of the weight percentage and size of the iron oxide nanoparticles, and the textural parameters of the support on the magnetic properties of iron oxide/KIT-6 has been demonstrated. The magnetization increases with decreasing iron content in the pore channels of KIT-6, whereas coercivity decreases for the same samples. Among the KIT-6 materials studied, KIT-6 with 7.5 wt % of iron showed the highest saturation magnetic moment and magnetic remanence. However, all the samples register a coercivity of around 2000 Oe, which is generally observed for the hard magnetic materials. In addition, we have found a paramagnetic-to-superparamagnetic transition at low temperature for samples with different iron content at low temperature. The cause for this exciting transition is also discussed in detail. Magnetic properties of the iron oxide loaded KIT-6 were also compared with pure iron oxide and iron oxide loaded over SBA-15. It was found that iron oxide loaded KIT-6 showed the highest magnetization due to its 3D structure and large pore volume. The pore diameter of the iron oxide loaded KIT-6 support also plays a critical role in controlling the magnetization and the blocking temperature, which has a direct relation to the particle diameter and increases from 48 to 63 K with an increase in the pore diameter of the support from 8 to 11.3 nm.

Plant-derived phenolic compounds impair the remediation of acid mine drainage using treatment wetlands

The use of wetlands to remediate acid mine drainage has expanded rapidly since the realisation that acid coal mine drainage running into natural sphagnum wetlands undergoes an increase in pH and a precipitation of metals. However, our study suggests that the inclusion of plants in the acid mine drainage treatment system may be questionable, due to inefficiencies caused by exudation of dissolved organic carbon (DOC), and in particular its phenolic constituents. They complex with iron, causing increased solubility, the exact opposite of what is required to facilitate amelioration. The addition of minewater to planted wetland mesocosms initially caused a decline in Fe concentrations, typically from over 1100 to a low of 75mgL−1. However, it increased higher than 300mgL−1 after 15 days. The rise in iron occurred concurrently with DOC and phenolic increases; 15–69 and 5–15mgL−1, respectively, for Eriophorum angustifolium. Removal of DOC by precipitation with calcium lowered the DOC abundance, but without a simultaneous decrease in iron concentration. The concentration of one fraction of the DOC, phenolic compounds, did not decline, and we propose that the Fe was complexed with that phenolic DOC pool. The proposal was confirmed by enzymic depletion of the phenolic compounds using phenol oxidase. Our findings suggest that phenolic complexation represents a potent constraint on wetland-based bioremediation of iron in acid mine drainage.

Study of Structure and Li&lt;sup&gt;+&lt;/sup&gt; Ions Dynamics in Presence of Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; in Bi&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;∙B&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Glasses

Glasses having composition xLi2O∙(30-x)Fe2O3∙20Bi2O3∙50B2O3 (0 ≤ x ≤ 30, in mol%) have been prepared using normal melt-quench technique. The variation in density and molar volume with composition has been investigated in terms of the structural modification that takes place in the glass matrix on decreasing Fe2O3. Infrared spectra of these glasses were recorded over continuous spectral range (400-4000 cm-1) in an attempt to study their structure systematically. IR spectra show that with increase in Li2O/Fe2O3 ratio there is formation of more structural units (e.g. [FeO4/2]-Li+) in the glass network. Bi3+ cations are present as [BiO6] octahedral units and acts as modifier in this glass system. Further, the effect of transition metal ions (iron) on the dynamics of lithium bismuth borate glasses has been studied in the frequency range of 20 Hz - 1 MHz and in the temperature range 240 – 350 °C using impedance spectroscopy. Possible conduction mechanisms are discussed. Various AC and DC electrical and dielectric parameters have been calculated and analyzed. The results show that the contribution of electronic conduction towards conductivity decreases with decreasing iron concentration, which is understood to be due to hopping of electrons from Fe2+→Fe3+. The frequency dependent conductivity has been studied using both conductivity and modulus formalism. The absence of maximum observed in dielectric permittivity in the temperature and frequency range studied, indicate the non-ferroelectric behavior of the glasses.

Involvement of Reductive Stress in the Cardiomyopathy in Transgenic Mice With Cardiac-Specific Overexpression of Heat Shock Protein 27

Oxidative stress plays an important role in cardiac diseases, which has been well demonstrated, whereas the role of reductive stress has been poorly investigated. We and others have shown previously that heat shock protein 27 (Hsp27) plays a role as an antioxidant. To investigate whether overexpression of Hsp27 could lead to reductive stress and result in cardiomyopathy, we generated transgenic mice with different expression levels of Hsp27. We observed that transgenic mice with high levels of Hsp27 developed cardiomyopathy. The myopathic hearts were under reductive stress, which was evidenced by an increased ratio of reduced glutathione/oxidized glutathione and a decreased level of reactive oxygen species. In addition, upregulated glutathione peroxidase 1 and decreased iron content were revealed in the myopathic hearts. More importantly, inhibition of glutathione peroxidase 1 significantly attenuated the development of cardiomyopathy. The data indicate that the Hsp27-induced cardiomyopathy could be attributed to, at least in part, upregulation of glutathione peroxidase 1. Our findings suggest that reductive stress plays an important role in the development of cardiomyopathy and that Hsp27 may serve as a potential target for the treatment of patients with cardiomyopathy.