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Sample records for high brain iron

  1. Brain iron homeostasis.

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    Moos, Torben

    2002-11-01

    Iron is essential for virtually all types of cells and organisms. The significance of the iron for brain function is reflected by the presence of receptors for transferrin on brain capillary endothelial cells. The transport of iron into the brain from the circulation is regulated so that the extraction of iron by brain capillary endothelial cells is low in iron-replete conditions and the reverse when the iron need of the brain is high as in conditions with iron deficiency and during development of the brain. Whereas there is good agreement that iron is taken up by means of receptor-mediated uptake of iron-transferrin at the brain barriers, there are contradictory views on how iron is transported further on from the brain barriers and into the brain extracellular space. The prevailing hypothesis for transport of iron across the BBB suggests a mechanism that involves detachment of iron from transferrin within barrier cells followed by recycling of apo-transferrin to blood plasma and release of iron as non-transferrin-bound iron into the brain interstitium from where the iron is taken up by neurons and glial cells. Another hypothesis claims that iron-transferrin is transported into the brain by means of transcytosis through the BBB. This thesis deals with the topic "brain iron homeostasis" defined as the attempts to maintain constant concentrations of iron in the brain internal environment via regulation of iron transport through brain barriers, cellular iron uptake by neurons and glia, and export of iron from brain to blood. The first part deals with transport of iron-transferrin complexes from blood to brain either by transport across the brain barriers or by uptake and retrograde axonal transport in motor neurons projecting beyond the blood-brain barrier. The transport of iron and transport into the brain was examined using radiolabeled iron-transferrin. Intravenous injection of [59Fe-125]transferrin led to an almost two-fold higher accumulation of 59Fe than of

  2. Susceptibility Contrast in High Field MRI of Human Brain as a Function of Tissue Iron Content

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    Yao, Bing; Li, Tie-Qiang; van Gelderen, Peter; Shmueli, Karin; de Zwart, Jacco A.; Duyn, Jeff H.

    2009-01-01

    Magnetic susceptibility provides an important contrast mechanism for MRI. Increasingly, susceptibility-based contrast is being exploited to investigate brain tissue microstructure and to detect abnormal levels of brain iron as these have been implicated in a variety of neuro-degenerative diseases. However, it remains unclear to what extent magnetic susceptibility-related contrast at high field relates to actual brain iron concentrations. In this study, we performed susceptibility weighted imaging as a function of field strength on healthy brains in vivo and post-mortem brain tissues at 1.5T, 3T and 7T. Iron histology was performed on the tissue samples for comparison. The calculated susceptibility-related parameters R2* and signal frequency shift in four iron-rich regions (putamen, globus pallidus, caudate, and thalamus) showed an almost linear dependence (r=0.90 for R2*; r=0.83 for phase, p<0.01) on field strength, suggesting that potential ferritin saturation effects are not relevant to susceptibility-weighted contrast for field strengths up to 7T. The R2* dependence on the putative (literature-based) iron concentration was 0.048 Hz/Tesla/ppm. The histological data from brain samples confirmed the linear dependence of R2* on field strength and showed a slope against iron concentration of 0.0099 Hz/Tesla/ppm dry-weight, which is equivalent to 0.05 Hz/Tesla/ppm wet-weight and closely matched the calculated value in vivo. These results confirm the validity of using susceptibility-weighted contrast as an indicator of iron content in iron-rich brain regions. The absence of saturation effects opens the way to exploit the benefits of MRI at high field strengths for the detection of iron distributions with high sensitivity and resolution. PMID:19027861

  3. High-field magnetic resonance imaging of brain iron: birth of a biomarker?

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    Schenck, John F; Zimmerman, Earl A

    2004-11-01

    The brain has an unusually high concentration of iron, which is distributed in an unusual pattern unlike that in any other organ. The physiological role of this iron and the reasons for this pattern of distribution are not yet understood. There is increasing evidence that several neurodegenerative diseases are associated with altered brain iron metabolism. Understanding these dysmetabolic conditions may provide important information for their diagnosis and treatment. For many years the iron distribution in the human brain could be studied effectively only under postmortem conditions. This situation was changed dramatically by the finding that T2-weighted MR imaging at high field strength (initially 1.5 T) appears to demonstrate the pattern of iron distribution in normal brains and that this imaging technique can detect changes in brain iron concentrations associated with disease states. Up to the present time this imaging capability has been utilized in many research applications but it has not yet been widely applied in the routine diagnosis and management of neurodegenerative disorders. However, recent advances in the basic science of brain iron metabolism, the clinical understanding of neurodegenerative diseases and in MRI technology, particularly in the availability of clinical scanners operating at the higher field strength of 3 T, suggest that iron-dependent MR imaging may soon provide biomarkers capable of characterizing the presence and progression of important neurological disorders. Such biomarkers may be of crucial assistance in the development and utilization of effective new therapies for Alzheimer's and Parkinson's diseases, multiple sclerosis and other iron-related CNS disorders which are difficult to diagnose and treat.

  4. Changes in brain iron concentration after exposure to high-altitude hypoxia measured by quantitative susceptibility mapping.

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    Chen, Lin; Cai, Congbo; Yang, Tianhe; Lin, Jianzhong; Cai, Shuhui; Zhang, Jiaxing; Chen, Zhong

    2017-02-15

    Hypoxia can induce physiological changes. This study aims to explore effects of high-altitude (HA) hypoxia on cerebral iron concentration. Twenty-nine healthy sea-level participants were tested shortly before and after approximately 4-week adaptation to the HA environment at fQinghai-Tibet Plateau (4200m), and were re-investigated after re-adaptation to the sea-level environment one year later. Iron concentration was quantified with quantitative susceptibility mapping (QSM), and the results were compared with transverse relaxation rate (R(*)2) measurements. The variations of magnetic susceptibility indicate that the iron concentration in gray matter regions, especially in basal ganglia, including caudate nucleus, putamen, globus pallidus and substantia nigra, increases significantly after HA exposure. This increase appears consistent with the conclusion from R(*)2 value variations. However, unlike QSM, the R(*)2 value fails to demonstrate the statistical difference of iron content in red nucleus. The re-investigation results show that most variations are recovered after sea-level re-adaptation for one year. Additionally, hemisphere- and gender-related differences in iron concentration changes were analyzed among cerebral regions. The results show greater possibilities in the right hemisphere and females. Further studies based on diffusion tensor imaging (DTI) suggest that the fractional anisotropy increases and the mean diffusivity decreases after HA exposure in six deep gray matter nuclei, with linear dependence on iron concentration only in putamen. In conclusion, the magnetic susceptibility value can serve as a quantitative marker of brain iron, and variations of regional susceptibility reported herein indicate that HA hypoxia can result in significant iron deposition in most deep gray matter regions. Additionally, the linear dependence of DTI metrics on iron concentration in putamen indicates a potential relationship between ferritin and water diffusion.

  5. Hepcidin Suppresses Brain Iron Accumulation by Downregulating Iron Transport Proteins in Iron-Overloaded Rats.

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    Du, Fang; Qian, Zhong-Ming; Luo, Qianqian; Yung, Wing-Ho; Ke, Ya

    2015-08-01

    Iron accumulates progressively in the brain with age, and iron-induced oxidative stress has been considered as one of the initial causes for Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the role of hepcidin in peripheral organs and its expression in the brain, we hypothesized that this peptide has a role to reduce iron in the brain and hence has the potential to prevent or delay brain iron accumulation in iron-associated neurodegenerative disorders. Here, we investigated the effects of hepcidin expression adenovirus (ad-hepcidin) and hepcidin peptide on brain iron contents, iron transport across the brain-blood barrier, iron uptake and release, and also the expression of transferrin receptor-1 (TfR1), divalent metal transporter 1 (DMT1), and ferroportin 1 (Fpn1) in cultured microvascular endothelial cells and neurons. We demonstrated that hepcidin significantly reduced brain iron in iron-overloaded rats and suppressed transport of transferrin-bound iron (Tf-Fe) from the periphery into the brain. Also, the peptide significantly inhibited expression of TfR1, DMT1, and Fpn1 as well as reduced Tf-Fe and non-transferrin-bound iron uptake and iron release in cultured microvascular endothelial cells and neurons, while downregulation of hepcidin with hepcidin siRNA retrovirus generated opposite results. We concluded that, under iron-overload, hepcidin functions to reduce iron in the brain by downregulating iron transport proteins. Upregulation of brain hepcidin by ad-hepcidin emerges as a new pharmacological treatment and prevention for iron-associated neurodegenerative disorders.

  6. Iron biomineralization of brain tissue and neurodegenerative disorders

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    Mikhaylova (Mikhailova), Albina

    The brain is an organ with a high concentration of iron in specific areas, particularly in the globus pallidus, the substantia nigra, and the red nucleus. In certain pathological states, such as iron overload disease and neurodegenerative disorders, a disturbed iron metabolism can lead to increased accumulation of iron not only in these areas, but also in the brain regions that are typically low in iron content. Recent studies of the physical and magnetic properties of metalloproteins, and in particular the discovery of biogenic magnetite in human brain tissue, have raised new questions about the role of biogenic iron formations in living organisms. Further investigations revealed the presence of magnetite-like crystalline structures in human ferritin, and indicated that released ferritin iron might act as promoter of oxidative damage to tissue, therefore contributing to pathogenesis of neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases. The purpose of this work was to examine the elemental composition and structure of iron deposits in normal brain tissue as well as tissue affected by neurodegenerative disorders. Employing the methods of X-ray microfocus fluorescence mapping, X-ray Absorption Near Edge Structure (XANES), X-ray Absorption Fine Structure spectroscopy (XAFS), and light and electron microscopic examinations allows one to obtain qualitative as well as quantitative data with respect to the cellular distribution and chemical state of iron at levels not detected previously. The described tissue preparation technique allows not only satisfactory XAS iron elemental imaging in situ but also multimodal examination with light and electron microscopes of the same samples. The developed protocol has assured consistent and reproducible results on relatively large sections of flat-embedded tissue. The resulting tissue samples were adequate for XAS examination as well as sufficiently well-preserved for future microscopy studies

  7. Neurodegeneration with Brain Iron Accumulation: An Overview

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    Seyed Hassan TONEKABONI*

    2014-12-01

    Full Text Available How to Cite This Article: Tonekaboni SH, Mollamohammadi M. Neurodegeneration with Brain Iron Accumulation: An Overview. Iran J Child Neurol. 2014 Autumn;8(4: 1-8.AbstractObjectiveNeurodegeneration with brain iron accumulation (NBIA is a group of neurodegenerative disorder with deposition of iron in the brain (mainly Basal Ganglia leading to a progressive Parkinsonism, spasticity, dystonia, retinal degeneration, optic atrophy often accompanied by psychiatric manifestations and cognitive decline. 8 of the 10 genetically defined NBIA types are inherited as autosomal recessive and the remaining two by autosomal dominant and X-linked dominant manner. Brain MRI findings are almost specific and show abnormal brain iron deposition in basal ganglia some other related anatomicallocations. In some types of NBIA cerebellar atrophy is the major finding in MRI.ReferencesShevel M. Racial hygiene, activeeuthanasia, and Julius Hallervorden. Neurology 1992;42:2214-2219.HayflickSJ. Neurodegeneration with brain Iron accumulation: from genes to pathogenesis.Semin Pediatr Neurol 2006;13:182-185.Zhou B, Westawy SK, Levinson B, et al. A novel pantothenate kinase gene(PANK2 is defective in Hallervorden-Spatzsyndrome. Nat Genet 2001;28:345- 349.www.ncbi.nlm.nihgov/NBK111Y/university of Washington, seattle. Allison Gregory and Susan Hayflick.Paisan-Ruiz C, Li A, Schneider SA, et al. Widesread Levy body and tau accumulation in childhood and adult onset dystonia-parkinsonism cases with PLA2G6 mutations. Neurobiol Aging 2012;33:814-823.Dick KJ, Eckhardt M, Paison-Ruiz C, et al. Mutation of FA2H underlies a complicated form of hereditary spastic paraplegia(SPG 35. Hum Mutat 31: E1251-E1260.Edvardson S, Hama H, Shaag A, et al. Mutation in the fatty acid 2-Hydroxylase gene are associated with leukodystrophy with spastic paraparesis and dystonia. Am I Hum Genet 2008;83:647-648.Schneider SA, Aggarwal A, Bhatt m, et al. Severe tongue protrusion dystonia: clinical syndromes

  8. Expression of iron-related genes in human brain and brain tumors

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    Britton Robert S

    2009-04-01

    Full Text Available Abstract Background Defective iron homeostasis may be involved in the development of some diseases within the central nervous system. Although the expression of genes involved in normal iron balance has been intensively studied in other tissues, little is known about their expression in the brain. We investigated the mRNA levels of hepcidin (HAMP, HFE, neogenin (NEO1, transferrin receptor 1 (TFRC, transferrin receptor 2 (TFR2, and hemojuvelin (HFE2 in normal human brain, brain tumors, and astrocytoma cell lines. The specimens included 5 normal brain tissue samples, 4 meningiomas, one medulloblastoma, 3 oligodendrocytic gliomas, 2 oligoastrocytic gliomas, 8 astrocytic gliomas, and 3 astrocytoma cell lines. Results Except for hemojuvelin, all genes studied had detectable levels of mRNA. In most tumor types, the pattern of gene expression was diverse. Notable findings include high expression of transferrin receptor 1 in the hippocampus and medulla oblongata compared to other brain regions, low expression of HFE in normal brain with elevated HFE expression in meningiomas, and absence of hepcidin mRNA in astrocytoma cell lines despite expression in normal brain and tumor specimens. Conclusion These results indicate that several iron-related genes are expressed in normal brain, and that their expression may be dysregulated in brain tumors.

  9. Profile of altered brain iron acquisition in restless legs syndrome

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    Ponnuru, Padmavathi; Wang, Xin-Sheng; Patton, Stephanie M.; Allen, Richard P.; Earley, Christopher J.

    2011-01-01

    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

  10. Profile of altered brain iron acquisition in restless legs syndrome.

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    Connor, James R; Ponnuru, Padmavathi; Wang, Xin-Sheng; Patton, Stephanie M; Allen, Richard P; Earley, Christopher J

    2011-04-01

    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

  11. Iron uptake and transport at the blood-brain barrier

    DEFF Research Database (Denmark)

    Larsen, Annette Burkhart; Thomsen, Louiza Bohn; Moos, Torben

    The mechanism by which iron is transported across the blood-brain barrier (BBB) remains controversial, and in this study we aimed to further clarify mechanisms by which iron is transported into the brain. We analyzed and compared the mRNA and protein expression of a variety of proteins involved i...... of hepcidin on iron efflux would indicate that ferroportin plays a role for iron efflux of ferrous non-transferrin bound iron at the BBB. Collectively, our data indicate that both routes are significant for transport of iron through the BBB initiated by receptor-mediated uptake of holo......-transferrin at the luminal side of brain capillaries and cellular entry in endosomes followed by: i) Transcytosis of holo-transferrin containing iron, and ii) Stepwise transport of iron through the endothelial cells from the endosomes via ferric reduction by Steap 2 and 3, transport of ferrous iron through the endosomal...... membrane to the cytosol mediated by DMT1, transport of ferrous iron through the abluminal endothelial cell membrane by ferroportin, and oxidation by the ferrooxidases ceruloplasmin and hephaestin. The two mechanisms for transport of iron at the BBB both explain how iron can enter the brain extracellular...

  12. The Effects of Dietary Fat and Iron Interaction on Brain Regional Iron Contents and Stereotypical Behaviors in Male C57BL/6J Mice

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    Lumei Liu

    2016-07-01

    Full Text Available Adequate brain iron levels are essential for enzyme activities, myelination, and neurotransmitter synthesis in the brain. Although systemic iron deficiency has been found in genetically or dietary-induced obese subjects, the effects of obesity-associated iron dysregulation in brain regions have not been examined. The objective of this study was to examine the effect of dietary fat and iron interaction on brain regional iron contents and regional-associated behavior patterns in a mouse model. Thirty C57BL/6J male weanling mice were randomly assigned to six dietary treatment groups (n=5 with varying fat (control/high and iron (control/high/low contents. The stereotypical behaviors were measured during the 24th week. Blood, liver, and brain tissues were collected at the end of the 24th week. Brains were dissected into the hippocampus, midbrain, striatum, and thalamus regions. Iron contents and ferritin-H (FtH protein and mRNA expressions in these regions were measured. Correlations between stereotypical behaviors and brain regional iron contents were analyzed at the 5% significance level. Results showed that high-fat diet altered the stereotypical behaviors such as inactivity and total distance traveled (P<0.05. The high-fat diet altered brain iron contents and ferritin-H (FtH protein and mRNA expressions in a regional-specific manner: 1 high-fat diet significantly decreased the brain iron content in the striatum (P<0.05, but not other regions; and 2 thalamus has a more distinct change in FtH mRNA expression compared to other regions. Furthermore, high-fat diet resulted in a significant decreased total distance traveled and a significant correlation between iron content and sleeping in midbrain (P<0.05. Dietary iron also decreased brain iron content and FtH protein expression in a regionally specific manner. The effect of interaction between dietary fat and iron was observed in brain iron content and behaviors. All these findings will lay

  13. Impairment of interrelated iron- and copper homeostatic mechanisms in brain contributes to the pathogenesis of neurodegenerative disorders

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    Tina eSkjørringe

    2012-09-01

    Full Text Available Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation is strictly regulated, and concordantly protective barriers i.e. the blood-brain barrier (BBB and the blood-cerebrospinal fluid (CSF barrier (BCB have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain-iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1 is involved in the uptake of both iron and copper. Furthermore, copper is an essential co-factor in numerous proteins that are vital for iron homeostasis and affects the binding of iron-response proteins to iron-response elements in the mRNA of the transferrin receptor, DMT1 and ferroportin, all highly involved in iron transport. Iron and copper are mainly taken up at the BBB, but the BCB also plays a vital role in the homeostasis of the two metals, in terms of sequestering, uptake and efflux of iron and copper from the brain. Inside the brain, iron and copper are taken up by neurons and glia cells that express various transporters

  14. Brain iron deficiency and excess; cognitive impairment and neurodegeneration with involvement of striatum and hippocampus.

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    Youdim, M B H

    2008-08-01

    While iron deficiency is not perceived as a life threatening disorder, it is the most prevalent nutritional abnormality in the world, and a better understanding of modes and sites of action, can help devise better treatment programs for those who suffer from it. Nowhere is this more important than in infants and children that make up the bulk of iron deficiency in society. Although the effects of iron deficiency have been extensively studied in systemic organs, until very recently little attention was paid to its effects on brain function. The studies of Oski at Johns Hopkin Medical School in 1974, demonstrating the impairment of learning in young school children with iron deficiency, prompted us to study its relevance to brain biochemistry and function in an animal model of iron deficiency. Indeed, rats made iron deficient have lowered brain iron and impaired behaviours including learning. This can become irreversible especially in newborns, even after long-term iron supplementation. We have shown that in this condition it is the brain striatal dopaminergic-opiate system which becomes defective, resulting in alterations in circadian behaviours, cognitive impairment and neurochemical changes closely associated with them. More recently we have extended these studies and have established that cognitive impairment may be closely associated with neuroanatomical damage and zinc metabolism in the hippocampus due to iron deficiency, and which may result from abnormal cholinergic function. The hippocampus is the focus of many studies today, since this brain structure has high zinc concentration and is highly involved in many forms of cognitive deficits as a consequence of cholinergic deficiency and has achieved prominence because of dementia in ageing and Alzheimer's disease. Thus, it is now apparent that cognitive impairment may not be attributed to a single neurotransmitter, but rather, alterations and interactions of several systems in different brain regions. In animal

  15. Uptake and metabolism of iron oxide nanoparticles in brain cells.

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    Petters, Charlotte; Irrsack, Ellen; Koch, Michael; Dringen, Ralf

    2014-09-01

    Magnetic iron oxide nanoparticles (IONPs) are used for various applications in biomedicine, for example as contrast agents in magnetic resonance imaging, for cell tracking and for anti-tumor treatment. However, IONPs are also known for their toxic effects on cells and tissues which are at least in part caused by iron-mediated radical formation and oxidative stress. The potential toxicity of IONPs is especially important concerning the use of IONPs for neurobiological applications as alterations in brain iron homeostasis are strongly connected with human neurodegenerative diseases. Since IONPs are able to enter the brain, potential adverse consequences of an exposure of brain cells to IONPs have to be considered. This article describes the pathways that allow IONPs to enter the brain and summarizes the current knowledge on the uptake, the metabolism and the toxicity of IONPs for the different types of brain cells in vitro and in vivo.

  16. Brain, blood, and iron : Perspectives on the roles of erythrocytes and iron in neurodegeneration

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    Prohaska, Rainer; Sibon, Ody C. M.; Rudnicki, Dobrila D.; Danek, Adrian; Hayflick, Susan J.; Verhaag, Esther M.; Vonk, Jan J.; Margolis, Russell L.; Walker, Ruth H.

    2012-01-01

    The terms "neuroacanthocytosis" (NA) and "neurodegeneration with brain iron accumulation" (NBIA) both refer to groups of genetically heterogeneous disorders, classified together due to similarities of their phenotypic or pathological findings. Even collectively, the disorders that comprise these set

  17. Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains

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    Habib, A.C.; Zheng, W.; Haacke, E.M.; Webb, S.; Nichol, H.; /SLAC

    2012-07-17

    To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.

  18. Distribution of iron in the parrot brain: conserved (pallidal) and derived (nigral) labeling patterns.

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    Roberts, T F; Brauth, S E; Hall, W S

    2001-12-01

    The distribution of iron in the brain of a vocal learning parrot, the budgerigar (Melopsittacus undulatus), was examined using iron histochemistry. In mammals, iron is a highly specific stain for the dorsal and ventral pallidal subdivision as well as specific cell groups in the brainstem, including the substantia nigra pars reticulata [Neuroscience 11 (1984) 595-603]. The purpose of this study was to compare the distribution of iron in the mammalian and avian brain focusing on pallidal and nigral cell groups. The results show that in the avian brain, iron stains oligodendrocytes, neurons and the neuropil. Cell staining changes dramatically along the rostrocaudal axis, with neuronal labeling confined to regions caudal to the thalamus and oligodendrocyte labeling denser in regions rostral to the dorsal thalamus. Many sensory forebrain regions contain appreciable iron labeling, including telencephalic vocal control nuclei. The dorsal and ventral subdivision of the avian pallidum, along with the basal ganglia component of the vocal control circuit, the magnicellular nucleus of the lobus parolfactorius, stain heavily for iron. Several brainstem regions, including nucleus rotundus, the medial spiriform nucleus (SpM), the principle nucleus of the trigeminal nerve, nucleus laminaris and scattered cell groups throughout the isthmus and pontine reticular formation stain intensely for iron. Within SpM neuronal labeling is more intense in the medial division while oligodendrocyte labeling is more intense in the lateral division. surprisingly no nigral iron staining was observed. Our results imply that iron is a conserved marker for the pallidum in birds and mammals, but that patterns of nigral staining have diverged in birds and mammals. Differences in iron staining patterns between birds and mammals may also reflect the relatively greater importance of the collothalamic visual pathways, pretectal-cerebellar pathways and specialized vocal learning circuitry in avian sensory

  19. Neurodegeneration with brain iron accumulation: update on pathogenic mechanisms.

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    Sonia eLevi

    2014-05-01

    Full Text Available Perturbation of iron distribution is observed in many neurodegenerative disorders, including Alzheimer’s and Parkinson’s disease, but the comprehension of the metal role in the development and progression of such disorders is still very limited. The combination of more powerful brain imaging techniques and faster genomic DNA sequencing procedures has allowed the description of a set of genetic disorders characterized by a constant and often early accumulation of iron in specific brain regions and the identification of the associated genes; these disorders are now collectively included in the category of Neurodegeneration with Brain Iron Accumulation (NBIA. So far 10 different genetic forms have been described but this number is likely to increase in short time. Two forms are linked to mutations in genes directly involved in iron metabolism: Neuroferritinopathy, associated to mutations in the FTL gene and Aceruloplasminaemia, where the ceruloplasmin gene product is defective. In the other forms the connection with iron metabolism is not evident at all and the genetic data let infer the involvement of other pathways: Pank2, COASY,Pla2G6, C19orf12, and FA2H genes seem to be related to lipid metabolism and to mitochondria functioning, WDR45 and ATP13A2 genes are implicated in lysosomal and autophagosome activity, while the C2orf37 gene encodes a nucleolar protein of unknown function. There is much hope in the scientific community that the study of the NBIA forms may provide important insight as to the link between brain iron metabolism and neurodegenerative mechanisms and eventually pave the way for new therapeutic avenues also for the more common neurodegenerative disorders. In this work we will review the most recent findings in the molecular mechanisms underlining the most common forms of NBIA and analyze their possible link with brain iron metabolism.

  20. Dystonia in neurodegeneration with brain iron accumulation : outcome of bilateral pallidal stimulation

    NARCIS (Netherlands)

    Timmermann, L.; Pauls, K. A. M.; Wieland, K.; Jech, R.; Kurlemann, G.; Sharma, N.; Gill, S. S.; Haenggeli, C. A.; Hayflick, S. J.; Hogarth, P.; Leenders, K. L.; Limousin, P.; Malanga, C. J.; Moro, E.; Ostrem, J. L.; Revilla, F. J.; Santens, P.; Schnitzler, A.; Tisch, S.; Valldeoriola, F.; Vesper, J.; Volkmann, J.; Woitalla, D.; Peker, S.

    Neurodegeneration with brain iron accumulation encompasses a heterogeneous group of rare neurodegenerative disorders that are characterized by iron accumulation in the brain. Severe generalized dystonia is frequently a prominent symptom and can be very disabling, causing gait impairment, difficulty

  1. Self-mutilation in neurodegeneration with brain iron accumulation

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    Sadanandavalli Retnaswami Chandra

    2015-01-01

    Full Text Available Neurodegeneration with brain iron accumulation (NBIA is the term applied to a heterogeneous group of disorders resulting in iron deposition in the basal ganglia. Well-known phenotypic features are progressive regression with extra pyramidal involvement and a variable course. A 10-year-old child born to consanguineous parents presented with progressive generalized opisthotonic dystonia, retrocollis, oromandibular dyskinesias, apraxia for swallowing, optic atrophy and severe self-mutilation of lips. MR imaging showed brain iron accumulation. Other causes of self-mutilation were excluded. Early infantile onset, ophisthotonic dystonia with oromandibular dyskinesias and characteristic MR images are suggestive of NBIA. There is only one case reported in the literature of self-mutilation in this condition.

  2. Increased brain iron deposition is a risk factor for brain atrophy in patients with haemodialysis: a combined study of quantitative susceptibility mapping and whole brain volume analysis.

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    Chai, Chao; Zhang, Mengjie; Long, Miaomiao; Chu, Zhiqiang; Wang, Tong; Wang, Lijun; Guo, Yu; Yan, Shuo; Haacke, E Mark; Shen, Wen; Xia, Shuang

    2015-08-01

    To explore the correlation between increased brain iron deposition and brain atrophy in patients with haemodialysis and their correlation with clinical biomarkers and neuropsychological test. Forty two patients with haemodialysis and forty one age- and gender-matched healthy controls were recruited in this prospective study. 3D whole brain high resolution T1WI and susceptibility weighted imaging were scanned on a 3 T MRI system. The brain volume was analyzed using voxel-based morphometry (VBM) in patients and to compare with that of healthy controls. Quantitative susceptibility mapping was used to measure and compare the susceptibility of different structures between patients and healthy controls. Correlation analysis was used to investigate the relationship between the brain volume, iron deposition and neuropsychological scores. Stepwise multiple regression analysis was used to explore the effect of clinical biomarkers on the brain volumes in patients. Compared with healthy controls, patients with haemodialysis showed decreased volume of bilateral putamen and left insular lobe (All P putamen, substantia nigra, red nucleus and dentate nucleus were significantly higher (All P putamen (P putamen (P < 0.05). Our study indicated increased brain iron deposition and dialysis duration was risk factors for brain atrophy in patients with haemodialysis. The decreased gray matter volume of the left insular lobe was correlated with neurocognitive impairment.

  3. The effects of sex on brain iron status in rats

    Institute of Scientific and Technical Information of China (English)

    HAO Qian; CHANG Yanzhong

    2015-01-01

    Objective:Iron plays essential roles in the human body. Studies have shown that iron is dis-tributed differently in male and female Rats in liver, spleen, bone marrow, kidney, heart. However, the effects of sex on iron distribution in central nervous system are not well established. Methods:To explore the effects of the above mentioned, in this study, female and male Sprague Dawley rats were used at 4 months of age. The synthesis of ferritin light chain (FTL), transferrin receptor1 (TfR1), ferroportin 1 (FPN1), divalent metal transporter 1 ( DMT1) in the cortex, hippocampus, striatum, cerebellum, and olfactory bulb was determined by Western blot a-nalysis. Results:The results showed that the levels of FTL protein in the cortex, hippocampus, striatum, cerebel-lum, and olfactory bulb were higher in female rats than in male rats, but the levels of TfR1 protein were lower in female rats than in male rats. There was no significant change in FPN1 and DMT1 expression in brain. Conclu-sions:These data suggest that sex have effects on brain iron status. Iron is distributed differently in central nervous system in male and female rats. However, the precise mechanisms need further study.

  4. Freezing resistance of high iron phoasphoaluminate cement

    Science.gov (United States)

    Zhang, S. X.; Lu, L. C.; Wang, S. D.; Zhao, P. Q.; Gong, C. C.

    2017-03-01

    The influence of freeze-thaw cycle on the mechanical properties of high iron phoasphoaluminate cement was investigated in the present study. The visual examination was conducted to evaluate the surface damage. The deterioration considering the weight loss, modulus loss of relative dynamic elastic and strength loss of mortar were also investigated. The morphology of hydration products were analysed by SEM. Compared with ordinary Portland cement and sulphoaluminate cement, the frost resistance of high iron phosphoraluminate cement is better. Hydration products of high iron phoasphoaluminate cement contain sheet crystals, and a lot of gel form a dense three-dimensional network structure, which results in a lower porosity. Different from ordinary Portland cement, the hydration product of high iron phoasphoaluminate cement does not contain Ca(OH)2, and low alkalinity reduces its osmotic pressure. The lower porosity and osmotic pressure are the two main reasons which causes in the higher frost resistance of high iron phoasphoaluminate cement.

  5. Analysis of iron oxidation at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, J.C.; Peng, K.Y.; Gadalla, A.M.; Gadalla, N. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering

    1995-10-01

    A new theory for the high-temperature oxidation of iron is proposed, in which the rate-limiting step is ternary diffusion of ferric, ferrous, and oxygen ions in the iron oxides that are formed. The predictions of this theory are compared with previously published experimental data. The only thermodynamic information required is a phase diagram.

  6. High toughness-high strength iron alloy

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R. (Inventor)

    1980-01-01

    An iron alloy is provided which exhibits strength and toughness characteristics at cryogenic temperatures. The alloy consists essentially of about 10 to 16 percent by weight nickel, about 0.1 to 1.0 percent by weight aluminum, and 0 to about 3 percent by weight copper, with the balance being essentially iron. The iron alloy is produced by a process which includes cold rolling at room temperature and subsequent heat treatment.

  7. Decreased serum hepcidin concentration correlates with brain iron deposition in patients with HBV-related cirrhosis.

    Directory of Open Access Journals (Sweden)

    Dong Lin

    Full Text Available PURPOSE: Excessive brain iron accumulation contributes to cognitive impairments in hepatitis B virus (HBV-related cirrhotic patients. The underlying mechanism remains unclear. Hepcidin, a liver-produced, 25-aminoacid peptide, is the major regulator of systemic iron metabolism. Abnormal hepcidin level is a key factor in some body iron accumulation or deficiency disorders, especially in those associated with liver diseases. Our study was aimed to explore the relationship between brain iron content in patients with HBV-related cirrhosis and serum hepcidin level. METHODS: Seventy HBV-related cirrhotic patients and forty age- sex-matched healthy controls were enrolled. Brain iron content was quantified by susceptibility weighted phase imaging technique. Serum hepcidin as well as serum iron, serum transferrin, ferritin, soluble transferrin receptor, total iron binding capacity, and transferrin saturation were tested in thirty cirrhotic patients and nineteen healthy controls. Pearson correlation analysis was performed to investigate correlation between brain iron concentrations and serum hepcidin, or other iron parameters. RESULTS: Cirrhotic patients had increased brain iron accumulation compared to controls in the left red nuclear, the bilateral substantia nigra, the bilateral thalamus, the right caudate, and the right putamen. Cirrhotic patients had significantly decreased serum hepcidin concentration, as well as lower serum transferring level, lower total iron binding capacity and higher transferrin saturation, compared to controls. Serum hepcidin level negatively correlated with the iron content in the right caudate, while serum ferritin level positively correlated with the iron content in the bilateral putamen in cirrhotic patients. CONCLUSIONS: Decreased serum hepcidin level correlated with excessive iron accumulation in the basal ganglia in HBV-related cirrhotic patients. Our results indicated that systemic iron overload underlined regional

  8. High temperature oxidation of iron-iron oxide core-shell nanowires composed of iron nanoparticles.

    Science.gov (United States)

    Krajewski, M; Brzozka, K; Lin, W S; Lin, H M; Tokarczyk, M; Borysiuk, J; Kowalski, G; Wasik, D

    2016-02-07

    This work describes an oxidation process of iron-iron oxide core-shell nanowires at temperatures between 100 °C and 800 °C. The studied nanomaterial was synthesized through a simple chemical reduction of iron trichloride in an external magnetic field under a constant flow of argon. The electron microscopy investigations allowed determining that the as-prepared nanowires were composed of self-assembled iron nanoparticles which were covered by a 3 nm thick oxide shell and separated from each other by a thin interface layer. Both these layers exhibited an amorphous or highly-disordered character which was traced by means of transmission electron microscopy and Mössbauer spectroscopy. The thermal oxidation was carried out under a constant flow of argon which contained the traces of oxygen. The first stage of process was related to slow transformations of amorphous Fe and amorphous iron oxides into crystalline phases and disappearance of interfaces between iron nanoparticles forming the studied nanomaterial (range: 25-300 °C). After that, the crystalline iron core and iron oxide shell became oxidized and signals for different compositions of iron oxide sheath were observed (range: 300-800 °C) using X-ray diffraction, Raman spectroscopy and Mössbauer spectroscopy. According to the thermal gravimetric analysis, the nanowires heated up to 800 °C under argon atmosphere gained 37% of mass with respect to their initial weight. The structure of the studied nanomaterial oxidized at 800 °C was mainly composed of α-Fe2O3 (∼ 93%). Moreover, iron nanowires treated above 600 °C lost their wire-like shape due to their shrinkage and collapse caused by the void coalescence.

  9. Deferoxamine inhibits iron induced hippocampal tau phosphorylation in the Alzheimer transgenic mouse brain.

    Science.gov (United States)

    Guo, Chuang; Wang, Pu; Zhong, Man-Li; Wang, Tao; Huang, Xue-Shi; Li, Jia-Yi; Wang, Zhan-You

    2013-01-01

    Prior work has shown that iron interacts with hyperphosphorylated tau, which contributes to the formation of neurofibrillary tangles (NFTs) in Alzheimer's disease (AD), whereas iron chelator desferrioxamine (DFO) slows down the clinical progression of the cognitive decline associated with this disease. However, the effects of DFO on tau phosphorylation in the presence or absence of iron have yet to be determined. Using amyloid precursor protein (APP) and presenilin 1 (PS1) double transgenic mouse brain as a model system, we investigated the effects and potential mechanisms of intranasal administration of DFO on iron induced abnormal tau phosphorylation. High-dose iron treatment markedly increased the levels of tau phosphorylation at the sites of Thr205, Thr231 and Ser396, whereas highly induced tau phosphorylation was abolished by intranasal administration of DFO in APP/PS1 transgenic mice. Moreover, DFO intranasal administration also decreases Fe-induced the activities of cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3β (GSK3β), which in turn suppressing tau phosphorylation. Cumulatively, our data show that intranasal DFO treatment exerts its suppressive effects on iron induced tau phosphorylation via CDK5 and GSK3β pathways. More importantly, elucidation of DFO mechanism in suppressing tau phosphorylation may provide insights for developing therapeutic strategies to combat AD.

  10. Genetic research advance on neurodegeneration with brain iron accumulation

    Directory of Open Access Journals (Sweden)

    Xiao-jun HUANG

    2017-07-01

    Full Text Available Neurodegeneration with brain iron accumulation (NBIA is a neurodegenerative disorder characterized by abnormal accumulation of iron in central nervous system. Common clinical symptoms in NBIA include different types of dyskinesia, pyramidal tract involvement, cerebellar ataxia, peripheral neuropathy, autonomic neuropathy, cognitive impairment and visual dysfunction. So far, 10 genes have been identified as the causative gene for NBIA subtypes, which are PANK2, COASY, PLA2G6, C19orf12, FA2H, WDR45, ATP13A2, FTL, CP and DCAF17. The pathogenesis of NBIA involves mitochondrial involvement, oxidative stress damage, lipid metabolism and autophagy. Furthermore, NBIA may share the same pathogenetic mechanism with some other neurodegenerative disorders, such as Parkinson's disease (PD, frontotemporal dementia (FTD and amyotrophic lateral sclerosis (ALS. DOI: 10.3969/j.issn.1672-6731.2017.07.004

  11. Na+/H+ Exchanger 9 Regulates Iron Mobilization at the Blood Brain Barrier in Response to Iron Starvation.

    Science.gov (United States)

    Beydoun, Rami; Hamood, Mohamed A; Gomez Zubeita, Daniela M; Kondapalli, Kalyan C

    2017-01-27

    Iron is essential for brain function, with loss of iron homeostasis in the brain linked to neurological diseases ranging from rare syndromes to more common disorders, such as Parkinson's and Alzheimer's diseases. Iron entry into the brain is regulated by the blood-brain barrier (BBB). Molecular mechanisms regulating this transport are poorly understood. Using an in vitro model of the BBB, we identify NHE9, an endosomal cation/proton exchanger, as a novel regulator of this system. Human brain microvascular endothelial cells (hBMVECs) that constitute the BBB receive brain-iron status information via paracrine signals from ensheathing astrocytes. In hBMVECs, we show that NHE9 expression is upregulated very early in a physiological response invoked by paracrine signals from iron-starved astrocytes. Ectopic expression of NHE9 in hBMVECs without external cues induced upregulation of the transferrin receptor (TfR) and downregulation of ferritin, leading to an increase in iron uptake. Mechanistically, we demonstrate that NHE9 localizes to recycling endosomes in hBMVECs where it raises the endosomal pH. The ensuing alkalization of the endosomal lumen increased translocation of TfRs to the hBMVEC membrane. TfRs on the membrane were previously shown to facilitate both recycling-dependent and independent iron uptake. We propose NHE9 regulates TfR-dependent, recycling-independent iron uptake in hBMVECs by fine-tuning the endosomal pH in response to paracrine signals and is therefore an important regulator in iron mobilization pathway at the BBB.

  12. Helicobacter pylori Infection Induces Anemia, Depletes Serum Iron Storage, and Alters Local Iron-Related and Adult Brain Gene Expression in Male INS-GAS Mice.

    Science.gov (United States)

    Burns, Monika; Muthupalani, Sureshkumar; Ge, Zhongming; Wang, Timothy C; Bakthavatchalu, Vasudevan; Cunningham, Catriona; Ennis, Kathleen; Georgieff, Michael; Fox, James G

    2015-01-01

    Iron deficiency anemia (IDA) affects > 500 million people worldwide, and is linked to impaired cognitive development and function in children. Helicobacter pylori, a class 1 carcinogen, infects about half of the world's population, thus creating a high likelihood of overlapping risk. This study determined the effect of H. pylori infection on iron homeostasis in INS-GAS mice. Two replicates of INS-GAS/FVB male mice (n = 9-12/group) were dosed with H. pylori (Hp) strain SS1 or sham dosed at 6-9 weeks of age, and were necropsied at 27-29 weeks of age. Hematologic and serum iron parameters were evaluated, as was gene expression in gastric and brain tissues. Serum ferritin was lower in Hp SS1-infected mice than uninfected mice (p in mice infected with Hp SS1 compared to sham-dosed controls (pin gastric tissue of Hp SS1-infected mice (pin myelination (myelin basic protein (Mbp) and proteolipid protein 2 (Plp2)) was downregulated in infected mice (p = 0.001 and p = 0.02). Expression of synaptic plasticity markers (brain derived neurotrophic factor 3 (Bdnf3), Psd95 (a membrane associated guanylate kinase), and insulin-like growth factor 1 (Igf1)) was also downregulated in Hp SS1-infected mice (p = 0.09, p = 0.04, p = 0.02 respectively). Infection of male INS-GAS mice with Hp SS1, without concurrent dietary iron deficiency, depleted serum ferritin, deregulated gastric and hepatic expression of iron regulatory genes, and altered iron-dependent neural processes. The use of Hp SS1-infected INS-GAS mice will be an appropriate animal model for further study of the effects of concurrent H. pylori infection and anemia on iron homeostasis and adult iron-dependent brain gene expression.

  13. R2* mapping for brain iron: associations with cognition in normal aging.

    Science.gov (United States)

    Ghadery, Christine; Pirpamer, Lukas; Hofer, Edith; Langkammer, Christian; Petrovic, Katja; Loitfelder, Marisa; Schwingenschuh, Petra; Seiler, Stephan; Duering, Marco; Jouvent, Eric; Schmidt, Helena; Fazekas, Franz; Mangin, Jean-Francois; Chabriat, Hugues; Dichgans, Martin; Ropele, Stefan; Schmidt, Reinhold

    2015-02-01

    Brain iron accumulates during aging and has been associated with neurodegenerative disorders including Alzheimer's disease. Magnetic resonance (MR)-based R2* mapping enables the in vivo detection of iron content in brain tissue. We investigated if during normal brain aging iron load relates to cognitive impairment in region-specific patterns in a community-dwelling cohort of 336 healthy, middle aged, and older adults from the Austrian Stroke Prevention Family Study. MR imaging and R2* mapping in the basal ganglia and neocortex were done at 3T. Comprehensive neuropsychological testing assessed memory, executive function, and psychomotor speed. We found the highest iron concentration in the globus pallidus, and pallidal and putaminal iron was significantly and inversely associated with cognitive performance in all cognitive domains, except memory. These associations were iron load dependent. Vascular brain lesions and brain volume did not mediate the relationship between iron and cognitive performance. We conclude that higher R2*-determined iron in the basal ganglia correlates with cognitive impairment during brain aging independent of concomitant brain abnormalities. The prognostic significance of this finding needs to be determined.

  14. Cast Iron With High Carbon Content

    Science.gov (United States)

    Curreri, P. A.; Hendrix, J. C.; Stefanescu, D. M.

    1986-01-01

    Method proposed for solidifying high-carbon cast iron without carbon particles segregating at upper surface. Solidification carried out in low gravity, for example on airplane flying free-fall parabolic trajectory. Many different microstructures obtained by proposed technique, and percentage by weight of carbon retained in melt much higher than at present.

  15. Regulation of quinolinic acid neosynthesis in mouse, rat and human brain by iron and iron chelators in vitro.

    Science.gov (United States)

    Stachowski, Erin K; Schwarcz, Robert

    2012-02-01

    Several lines of evidence indicate that excess iron may play an etiologically significant role in neurodegenerative disorders. This idea is supported, for example, by experimental studies in animals demonstrating significant neuroprotection by iron chelation. Here, we tested whether this effect might be related to a functional link between iron and the endogenous excitotoxin quinolinic acid (QUIN), a presumed pathogen in several neurological disorders. In particular, the present in vitro study was designed to examine the effects of Fe(2+), a known co-factor of oxygenases, on the activity of QUIN's immediate biosynthetic enzyme, 3-hydroxyanthranilic acid dioxygenase (3HAO), in the brain. In crude tissue homogenate, addition of Fe(2+) (2-40 μM) stimulated 3HAO activity 4- to 6-fold in all three species tested (mouse, rat and human). The slope of the iron curve was steepest in rat brain where an increase from 6 to 14 μM resulted in a more than fivefold higher enzyme activity. In all species, the Fe(2+)-induced increase in 3HAO activity was dose-dependently attenuated by the addition of ferritin, the main iron storage protein in the brain. The effect of iron was also readily prevented by N,N'-bis(2-hydroxybenzyl) ethylenediamine-N,N'-diacetic acid (HBED), a synthetic iron chelator with neuroprotective properties in vivo. All these effects were reproduced using neostriatal tissue obtained postmortem from normal individuals and patients with end-stage Huntington's disease. Our results suggest that QUIN levels and function in the mammalian brain might be tightly controlled by endogenous iron and proteins that regulate the bioavailability of iron.

  16. Altered brain iron homeostasis and dopaminergic function in Restless Legs Syndrome (Willis-Ekbom Disease).

    Science.gov (United States)

    Earley, Christopher J; Connor, James; Garcia-Borreguero, Diego; Jenner, Peter; Winkelman, John; Zee, Phyllis C; Allen, Richard

    2014-11-01

    Restless legs syndrome (RLS), also known as Willis-Ekbom Disease (WED), is a sensorimotor disorder for which the exact pathophysiology remains unclear. Brain iron insufficiency and altered dopaminergic function appear to play important roles in the etiology of the disorder. This concept is based partly on extensive research studies using cerebrospinal fluid (CSF), autopsy material, and brain imaging indicating reduced regional brain iron and on the clinical efficacy of dopamine receptor agonists for alleviating RLS symptoms. Finding causal relations, linking low brain iron to altered dopaminergic function in RLS, has required however the use of animal models. These models have provided insights into how alterations in brain iron homeostasis and dopaminergic system may be involved in RLS. The results of animal models of RLS and biochemical, postmortem, and imaging studies in patients with the disease suggest that disruptions in brain iron trafficking lead to disturbances in striatal dopamine neurotransmission for at least some patients with RLS. This review examines the data supporting an iron deficiency-dopamine metabolic theory of RLS by relating the results from animal model investigations of the influence of brain iron deficiency on dopaminergic systems to data from clinical studies in patients with RLS. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Absorption and loss of iron in toddlers are highly correlated.

    Science.gov (United States)

    Fomon, Samuel J; Nelson, Steven E; Serfass, Robert E; Ziegler, Ekhard E

    2005-04-01

    For estimating the requirements for dietary iron, it is important to know the amount of iron that is lost from the body. Inevitable losses of iron have been determined in adult humans but not in infants or children. We administered (58)Fe, the least abundant stable isotope of iron, to free-living infants at 168 d of age (5.6 mo) and followed them to age 26 mo. There was no dietary restriction after isotope administration. Blood was obtained at regular intervals for determination of isotopic enrichment and indices of iron status. We estimated the quantity of circulating iron, noncirculating active iron, and storage iron at each age. The administered isotope equilibrated with total body iron by 13 mo of age. From 13 to 26 mo of age, we estimated inevitable loss and absorption of iron from the change in tracer abundance in circulating iron. The rate of decrease of tracer abundance was proportional to addition of tracee, i.e., absorption of iron. Conversely, the rate of decrease in quantity of tracer was proportional to removal of tracee, i.e., loss of iron. From 13 to 26 mo of age, iron absorption was (mean +/- SD) 0.49 +/- 0.13 mg/d and inevitable iron loss was 0.25 +/- 0.12 mg/d. Intersubject variability of iron loss and iron absorption was high, and iron loss and absorption were highly correlated (r = 0.789, P absorption from the diet was inadequate to maintain or increase iron nutritional status. The data suggest that, in this cohort, which may be representative, the intake of bioavailable iron from 13 to 26 mo of age was insufficient to maintain iron nutritional status.

  18. Recent studies of iron deficiency during brain development in nonhuman primates.

    Science.gov (United States)

    Golub, Mari S

    2010-01-01

    Recent studies of the effects of developmental iron deficiency (ID) and iron deficiency anemia in nonhuman primates have provided new insights into this widespread and well-recognized human nutritional deficiency. The rhesus monkey was the animal model in these experiments, which used extensive hematological and behavioral evaluations in addition to noninvasive brain measures. Two important findings were as follows: 1) different behavioral consequences depending on the timing of ID relative to brain developmental stages and 2) the potential for long-lasting changes in brain iron regulatory systems. Further work in this model, including integration with studies in humans and in laboratory rodents, is ongoing.

  19. Helicobacter pylori Infection Induces Anemia, Depletes Serum Iron Storage, and Alters Local Iron-Related and Adult Brain Gene Expression in Male INS-GAS Mice.

    Directory of Open Access Journals (Sweden)

    Monika Burns

    Full Text Available Iron deficiency anemia (IDA affects > 500 million people worldwide, and is linked to impaired cognitive development and function in children. Helicobacter pylori, a class 1 carcinogen, infects about half of the world's population, thus creating a high likelihood of overlapping risk. This study determined the effect of H. pylori infection on iron homeostasis in INS-GAS mice. Two replicates of INS-GAS/FVB male mice (n = 9-12/group were dosed with H. pylori (Hp strain SS1 or sham dosed at 6-9 weeks of age, and were necropsied at 27-29 weeks of age. Hematologic and serum iron parameters were evaluated, as was gene expression in gastric and brain tissues. Serum ferritin was lower in Hp SS1-infected mice than uninfected mice (p < 0.0001. Infected mice had a lower red blood cell count (p<0.0001, hematocrit (p < 0.001, and hemoglobin concentration (p <0.0001 than uninfected mice. Relative expression of gastric hepcidin antimicrobial peptide (Hamp was downregulated in mice infected with Hp SS1 compared to sham-dosed controls (p<0.001. Expression of bone morphogenic protein 4 (Bmp4, a growth factor upstream of hepcidin, was downregulated in gastric tissue of Hp SS1-infected mice (p<0.001. Hp SS1-infected mice had downregulated brain expression of tyrosine hydroxylase (Th (p = 0.02. Expression of iron-responsive genes involved in myelination (myelin basic protein (Mbp and proteolipid protein 2 (Plp2 was downregulated in infected mice (p = 0.001 and p = 0.02. Expression of synaptic plasticity markers (brain derived neurotrophic factor 3 (Bdnf3, Psd95 (a membrane associated guanylate kinase, and insulin-like growth factor 1 (Igf1 was also downregulated in Hp SS1-infected mice (p = 0.09, p = 0.04, p = 0.02 respectively. Infection of male INS-GAS mice with Hp SS1, without concurrent dietary iron deficiency, depleted serum ferritin, deregulated gastric and hepatic expression of iron regulatory genes, and altered iron-dependent neural processes. The use of Hp SS

  20. New findings about iron oxide nanoparticles and their different effects on murine primary brain cells.

    Science.gov (United States)

    Neubert, Jenni; Wagner, Susanne; Kiwit, Jürgen; Bräuer, Anja U; Glumm, Jana

    2015-01-01

    The physicochemical properties of superparamagnetic iron oxide nanoparticles (SPIOs) enable their application in the diagnostics and therapy of central nervous system diseases. However, since crucial information regarding side effects of particle-cell interactions within the central nervous system is still lacking, we investigated the influence of novel very small iron oxide particles or the clinically approved ferucarbotran or ferumoxytol on the vitality and morphology of brain cells. We exposed primary cell cultures of microglia and hippocampal neurons, as well as neuron-glia cocultures to varying concentrations of SPIOs for 6 and/or 24 hours, respectively. Here, we show that SPIO accumulation by microglia and subsequent morphological alterations strongly depend on the respective nanoparticle type. Microglial viability was severely compromised by high SPIO concentrations, except in the case of ferumoxytol. While ferumoxytol did not cause immediate microglial death, it induced severe morphological alterations and increased degeneration of primary neurons. Additionally, primary neurons clearly degenerated after very small iron oxide particle and ferucarbotran exposure. In neuron-glia cocultures, SPIOs rather stimulated the outgrowth of neuronal processes in a concentration- and particle-dependent manner. We conclude that the influence of SPIOs on brain cells not only depends on the particle type but also on the physiological system they are applied to.

  1. Impairment of interrelated iron- and copper homeostatic mechanisms in brain contributes to the pathogenesis of neurodegenerative disorders

    DEFF Research Database (Denmark)

    Skjørringe, Tina; Møller, Lisbeth Birk; Moos, Torben

    2012-01-01

    is strictly regulated, and concordantly protective barriers, i.e., the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (BCB) have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead......Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation...... to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1...

  2. Expression of Iron-Related Proteins at the Neurovascular Unit Supports Reduction and Reoxidation of Iron for Transport Through the Blood-Brain Barrier

    DEFF Research Database (Denmark)

    Burkhart, Annette; Skjørringe, Tina; Johnsen, Kasper Bendix;

    2015-01-01

    The mechanisms for iron transport through the blood-brain barrier (BBB) remain a controversy. We analyzed for expression of mRNA and proteins involved in oxidation and transport of iron in isolated brain capillaries from dietary normal, iron-deficient, and iron-reverted rats. The expression...... was also investigated in isolated rat brain endothelial cells (RBECs) and in immortalized rat brain endothelial (RBE4) cells grown as monoculture or in hanging culture inserts with defined BBB properties. Transferrin receptor 1, ferrireductases Steap 2 and 3, divalent metal transporter 1 (DMT1...... cells provide the machinery for receptor-mediated uptake of ferric iron-containing transferrin. Ferric iron can then undergo reduction to ferrous iron by ferrireductases inside endosomes followed by DMT1-mediated pumping into the cytosol and subsequently cellular export by ferroportin. The expression...

  3. Coexistence of Copper in the Iron-Rich Particles of Aceruloplasminemia Brain.

    Science.gov (United States)

    Yoshida, Kunihiro; Hayashi, Hisao; Wakusawa, Shinya; Shigemasa, Ryota; Koide, Ryoji; Ishikawa, Tetsuya; Tatsumi, Yasuaki; Kato, Koichi; Ohara, Shinji; Ikeda, Shu-Ichi

    2017-01-01

    The interaction between iron and copper has been discussed in association with human health and diseases for many years. Ceruloplasmin, a multi-copper oxidase, is mainly involved in iron metabolism and its genetic defect, aceruloplasminemia (ACP), shows neurological disorders and diabetes associated with excessive iron accumulation, but little is known about the state of copper in the brain. Here, we investigated localization of these metals in the brains of three patients with ACP using electron microscopes equipped with an energy-dispersive x-ray analyzer. Histochemically, iron deposition was observed mainly in the basal ganglia and dentate nucleus, and to lesser degree in the cerebral cortex of the patients, whereas copper grains were not detected. X-ray microanalysis identified two types of iron-rich particles in their brains: dense bodies, namely hemosiderins, and their aggregated inclusions. A small number of hemosiderins and most inclusions contained a significant amount of copper which was enough for distinct Cu x-ray images. These copper-containing particles were observed more frequently in the putamen and dentate nucleus than the cerebral cortex. Coexistence of iron and copper was supported by good correlations in the molecular ratios between these two metals in iron-rich particles with Cu x-ray image. Iron-dependent copper accumulation in iron-rich particles may suggest that copper recycling is enhanced to meet the increased requirement of cuproproteins in iron overload brain. In conclusion, the iron-rich particles with Cu x-ray image were found in the ACP brain.

  4. Reducing iron in the brain: a novel pharmacologic mechanism of huperzine A in the treatment of Alzheimer's disease.

    Science.gov (United States)

    Huang, Xiao-Tian; Qian, Zhong-Ming; He, Xuan; Gong, Qi; Wu, Ka-Chun; Jiang, Li-Rong; Lu, Li-Na; Zhu, Zhou-Jing; Zhang, Hai-Yan; Yung, Wing-Ho; Ke, Ya

    2014-05-01

    Huperzine A (HupA), a natural inhibitor of acetylcholinesterase derived from a plant, is a licensed anti-Alzheimer's disease (AD) drug in China and a nutraceutical in the United States. In addition to acting as an acetylcholinesterase inhibitor, HupA possesses neuroprotective properties. However, the relevant mechanism is unknown. Here, we showed that the neuroprotective effect of HupA was derived from a novel action on brain iron regulation. HupA treatment reduced insoluble and soluble beta amyloid levels, ameliorated amyloid plaques formation, and hyperphosphorylated tau in the cortex and hippocampus of APPswe/PS1dE9 transgenic AD mice. Also, HupA decreased beta amyloid oligomers and amyloid precursor protein levels, and increased A Disintegrin And Metalloprotease Domain 10 (ADAM10) expression in these treated AD mice. However, these beneficial effects of HupA were largely abolished by feeding the animals with a high iron diet. In parallel, we found that HupA decreased iron content in the brain and demonstrated that HupA also has a role to reduce the expression of transferrin-receptor 1 as well as the transferrin-bound iron uptake in cultured neurons. The findings implied that reducing iron in the brain is a novel mechanism of HupA in the treatment of Alzheimer's disease.

  5. Recent studies of iron deficiency during brain development in nonhuman primates

    OpenAIRE

    Golub, Mari S.

    2010-01-01

    Recent studies of the effects of developmental iron deficiency and iron deficiency anemia in nonhuman primates have provided new insights into this widespread and well-recognized human nutritional deficiency. The rhesus monkey was the animal model in these experiments which used extensive hematological and behavioral evaluations in addition to noninvasive brain measures. Two important findings were (1) different behavioral consequences depending on the timing of iron deficiency relative to br...

  6. Brain burdens of aluminum, iron, and copper and their relationships with amyloid-β pathology in 60 human brains.

    Science.gov (United States)

    Exley, Christopher; House, Emily; Polwart, Anthony; Esiri, Margaret M

    2012-01-01

    The deposition in the brain of amyloid-β as beta sheet conformers associated with senile plaques and vasculature is frequently observed in Alzheimer’s disease. While metals, primarily aluminum, iron, zinc, and copper, have been implicated in amyloid-β deposition in vivo, there are few data specifically relating brain metal burden with extent of amyloid pathologies in human brains. Herein brain tissue content of aluminum, iron, and copper are compared with burdens of amyloid-β, as senile plaques and as congophilic amyloid angiopathy, in 60 aged human brains. Significant observations were strong negative correlations between brain copper burden and the degree of severity of both senile plaque and congophilic amyloid angiopathy pathologies with the relationship with the former reaching statistical significance. While we did not have access to the dementia status of the majority of the 60 brain donors, this knowledge for just 4 donors allowed us to speculate that diagnosis of dementia might be predicted by a combination of amyloid pathology and a ratio of the brain burden of copper to the brain burden of aluminum. Taking into account only those donor brains with either senile plaque scores ≥4 and/or congophilic amyloid angiopathy scores ≥12, a Cu:Al ratio of <20 would predict that at least 39 of the 60 donors would have been diagnosed as suffering from dementia. Future research should test the hypothesis that, in individuals with moderate to severe amyloid pathology, low brain copper is a predisposition to developing dementia.

  7. Brain Food at High Altitude.

    Science.gov (United States)

    Jain, Vishal

    2016-01-01

    Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude.

  8. Late Onset Neurodegeneration with Brain-Iron Accumulation Presenting as Parkinsonism

    Directory of Open Access Journals (Sweden)

    Robert Fekete

    2012-01-01

    Full Text Available Neurodegeneration with brain-iron accumulation (NBIA encompasses a family of neurodegenerative disorders connected by evidence of abnormal brain iron deposition. Advances in imaging and genetic testing expanded the clinical spectrum of these disorders. Here, a case of parkinsonism and dystonia with orofacial stereotypies is presented. While the patient was initially diagnosed with Parkinson’s disease and placed on levodopa therapy, dopamine transporter imaging via (123I-FP-CIT SPECT (DaTSCAN was normal. MRI brain showed “eye of the tiger” sign on T2 weighted imaging. NBIA should be considered in the differential diagnosis of atypical parkinsonism.

  9. Age, gender, and hemispheric differences in iron deposition in the human brain: an in vivo MRI study.

    Science.gov (United States)

    Xu, Xiaojun; Wang, Qidong; Zhang, Minming

    2008-03-01

    It is well known that iron accumulates in the brains of patients with various neurodegenerative diseases. To better understand disease-related iron changes, it is necessary to know the physiological distribution and accumulation of iron in the human brain. Studies have shown that brain iron levels increase with aging. However, the effects of gender and hemispheric laterality on iron accumulation and distribution are not well established. In this study, we estimated the brain iron levels in vivo in 78 healthy adults ranging in age 22 to 78 years using magnetic susceptibility-weighted phase imaging. The effects of age, gender, and hemispheric location on brain iron levels were evaluated within the framework of a general linear model. We found that the left hemisphere had higher iron levels than the right in the putamen, globus pallidus, substantia nigra, thalamus, and frontal white matter. We argue that the hemispheric asymmetry of iron content may underlie that of the dopaminergic system and may be related to motor lateralization in humans. In addition, significant age-related iron accumulation occurred in the putamen, red nucleus, and frontal white matter, but no gender-related differences in iron levels were detected. The results of this study extend our knowledge of the physiological distribution and accumulation of iron in the human brain.

  10. sAPP modulates iron efflux from brain microvascular endothelial cells by stabilizing the ferrous iron exporter ferroportin.

    Science.gov (United States)

    McCarthy, Ryan C; Park, Yun-Hee; Kosman, Daniel J

    2014-07-01

    A sequence within the E2 domain of soluble amyloid precursor protein (sAPP) stimulates iron efflux. This activity has been attributed to a ferroxidase activity suggested for this motif. We demonstrate that the stimulation of efflux supported by this peptide and by sAPPα is due to their stabilization of the ferrous iron exporter, ferroportin (Fpn), in the plasma membrane of human brain microvascular endothelial cells (hBMVEC). The peptide does not bind ferric iron explaining why it does not and thermodynamically cannot promote ferrous iron autoxidation. This peptide specifically pulls Fpn down from the plasma membrane of hBMVEC; based on these results, FTP, for ferroportin-targeting peptide, correctly identifies the function of this peptide. The data suggest that in stabilizing Fpn via the targeting due to the FTP sequence, sAPP will increase the flux of iron into the cerebral interstitium. This inference correlates with the observation of significant iron deposition in the amyloid plaques characteristic of Alzheimer's disease. © 2014 The Authors.

  11. sAPP modulates iron efflux from brain microvascular endothelial cells by stabilizing the ferrous iron exporter ferroportin

    Science.gov (United States)

    McCarthy, Ryan C; Park, Yun-Hee; Kosman, Daniel J

    2014-01-01

    A sequence within the E2 domain of soluble amyloid precursor protein (sAPP) stimulates iron efflux. This activity has been attributed to a ferroxidase activity suggested for this motif. We demonstrate that the stimulation of efflux supported by this peptide and by sAPPα is due to their stabilization of the ferrous iron exporter, ferroportin (Fpn), in the plasma membrane of human brain microvascular endothelial cells (hBMVEC). The peptide does not bind ferric iron explaining why it does not and thermodynamically cannot promote ferrous iron autoxidation. This peptide specifically pulls Fpn down from the plasma membrane of hBMVEC; based on these results, FTP, for ferroportin-targeting peptide, correctly identifies the function of this peptide. The data suggest that in stabilizing Fpn via the targeting due to the FTP sequence, sAPP will increase the flux of iron into the cerebral interstitium. This inference correlates with the observation of significant iron deposition in the amyloid plaques characteristic of Alzheimer’s disease. PMID:24867889

  12. High temperature mechanical properties of iron aluminides

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2001-04-01

    Full Text Available Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the material, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered.

    Durante los últimos años se ha prestado mucha atención a la familia de intermetálicos Fe-Al, puesto que estos constituyen un considerable potencial como materiales de ingeniería en aplicaciones a temperaturas intermedias o altas, sobre todo en casos donde se necesita alta resistencia a la oxidación o corrosión. A pesar del considerable esfuerzo desarrollado para obtener aleaciones con mejores propiedades, su resistencia mecánica a alta temperatura no es muy elevada. Se discutirán los aspectos que contribuyen a la baja resistencia mecánica a temperatura elevada en función de la estructura de dislocaciones y los mecanismos de anclaje que operan en este intermetálico. Se considerarán, también, maneras alternativas para mejorar la resistencia a temperatura elevada mediante la modificación de la microestructura y la incorporación de partículas de segunda fase.

  13. Aluminium, iron and copper in human brain tissues donated to the Medical Research Council's Cognitive Function and Ageing Study.

    Science.gov (United States)

    House, Emily; Esiri, Margaret; Forster, Gill; Ince, Paul G; Exley, Christopher

    2012-01-01

    Aluminium, iron and copper are all implicated in the aetiology of neurodegenerative diseases including Alzheimer's disease. However, there are very few large cohort studies of the content of these metals in aged human brains. We have used microwave digestion and TH GFAAS to measure aluminium, iron and copper in the temporal, frontal, occipital and parietal lobes of 60 brains donated to the Cognitive Function and Ageing Study. Every precaution was taken to reduce contamination of samples and acid digests to a minimum. Actual contamination was estimated by preparing a large number of (170+) method blanks which were interspersed within the full set of 700+ tissue digests. Subtraction of method blank values (MBV) from tissue digest values resulted in metal contents in all tissues in the range, MBV to 33 μg g(-1) dry wt. for aluminium, 112 to 8305 μg g(-1) dry wt. for iron and MBV to 384 μg g(-1) dry wt. for copper. While the median aluminium content for all tissues was 1.02 μg g(-1) dry wt. it was informative that 41 brains out of 60 included at least one tissue with an aluminium content which could be considered as potentially pathological (> 3.50 μg g(-1) dry wt.). The median content for iron was 286.16 μg g(-1) dry wt. and overall tissue iron contents were generally high which possibly reflected increased brain iron in ageing and in neurodegenerative disease. The median content for copper was 17.41 μg g(-1) dry wt. and overall tissue copper contents were lower than expected for aged brains but they were commensurate with aged brains showing signs of neurodegenerative disease. In this study we have shown, in particular, the value of carrying out significant numbers of method blanks to identify unknown sources of contamination. When these values are subtracted from tissue digest values the absolute metal contents could be considered as conservative and yet they may still reflect aspects of ageing and neurodegenerative disease in individual brains.

  14. The effect of Iron Folic Acid Supplementation and Dietary Iron Intake in High Schools Female Students

    Directory of Open Access Journals (Sweden)

    2015-01-01

    Full Text Available Background & aim: Iron deficiency is one of the major public health problems imposing significant effect on the body and mind which has negative impacts on humans’ capability of. Increasing demand of the body, inadequate intake and decrease of absorbency are the major causes of anemia among teenage girls. The aim of this study was to evaluate the effect of dietary iron folic acid supplementation and dietary iron intake in high school girls. Methods: The present cross-sectional study was conducted on sixty female high school students at grade one and three in Yasuj, Iran. Biochemical markers of iron status were measured beforehand and afterwards of folic acid supplementation for 16 weeks. Food consumption patterns and iron intake were determined by frequency questionnaires. Data were analyzed using chi-square test, t-test by means of N4 analysis software. Results: Anemia, iron deficiency and iron deficiency anemia in grade one were 9.7%, 32.3% and 9.9% respectively, in addition to in grade three were 19.4% , 41.9% and 3.2% respectively. After iron folic acid supplementation, these indicators were 9.7%, 16.1% and 3.3% in grade one and in grade three were 9.7%, 22.6%, 0.0% respectively. Conclusion: Overall, it appeared that weekly iron folic acid supplementation in duration of 16 weeks per year, with dietary modification, could improve the indices of blood in high school girls. Key words: Anemia, iron deficiency, iron deficiency anemia, iron folic acid supplementation

  15. High-rate behaviour of iron ore pellet

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    Gustafsson Gustaf

    2015-01-01

    Full Text Available Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

  16. Adenosine receptors as markers of brain iron deficiency: Implications for Restless Legs Syndrome.

    Science.gov (United States)

    Quiroz, César; Gulyani, Seema; Ruiqian, Wan; Bonaventura, Jordi; Cutler, Roy; Pearson, Virginia; Allen, Richard P; Earley, Christopher J; Mattson, Mark P; Ferré, Sergi

    2016-12-01

    Deficits of sensorimotor integration with periodic limb movements during sleep (PLMS) and hyperarousal and sleep disturbances in Restless Legs Syndrome (RLS) constitute two pathophysiologically distinct but interrelated clinical phenomena, which seem to depend mostly on alterations in dopaminergic and glutamatergic neurotransmission, respectively. Brain iron deficiency is considered as a main pathogenetic mechanism in RLS. Rodents with brain iron deficiency represent a valuable pathophysiological model of RLS, although they do not display motor disturbances. Nevertheless, they develop the main neurochemical dopaminergic changes found in RLS, such as decrease in striatal dopamine D2 receptor density. On the other hand, brain iron deficient mice exhibit the characteristic pattern of hyperarousal in RLS, providing a tool to find the link between brain iron deficiency and sleep disturbances in RLS. The present study provides evidence for a role of the endogenous sleep-promoting factor adenosine. Three different experimental preparations, long-term (22 weeks) severe or moderate iron-deficient (ID) diets (3- or 7-ppm iron diet) in mice and short-term (3 weeks) severe ID diet (3-ppm iron diet) in rats, demonstrated a significant downregulation (Western blotting in mouse and radioligand binding saturation experiments in rat brain tissue) of adenosine A1 receptors (A1R) in the cortex and striatum, concomitant to striatal D2R downregulation. On the other hand, the previously reported upregulation of adenosine A2A receptors (A2AR) was only observed with severe ID in both mice and rats. The results suggest a key role for A1R downregulation in the PLMS and hyperarousal in RLS. Published by Elsevier Ltd.

  17. High doses of vitamin A impair iron absorption

    Directory of Open Access Journals (Sweden)

    Gabriel FR

    2012-10-01

    Full Text Available Fabíola Rainato Gabriel, Vivian MM Suen, Julio Sergio Marchini, José Eduardo Dutra de OliveiraDivision of Clinical Nutrition, Department of Internal Medicine, Ribeirão Preto School of Medicine, São Paulo University, São Paulo, BrazilObjective: The present study aimed to determine the influence of vitamin A on iron absorption when vitamin A and iron are administered together orally compared with the administration of iron alone.Methods: This was a randomized double-blind clinical trial conducted on healthy men with normal red blood cell indices. Five experiments were performed, with iron (10 mg; iron (10 mg plus vitamin A (450, 900 and 1800 µg, and placebo. After an 8-hour fast, basal (T0 blood samples were collected: basal (T0, 2 hours (T1, and 4 hours (T2 after the ingestion of the compounds to be studied. Iron was determined by inductively coupled plasma mass spectrometry. Serum ferritin was determined by an immunometric method, ie, by chemoluminescent enzyme immunoassay. Plasma retinol was measured by high-pressure liquid chromatography. Serum curves and the sum of the area under the curve adjusted to the mixed effects linear model were determined (P < 0.05.Results: Vitamin A at the doses of 450 and 900 µg had a stimulating effect, which, however, did not differ significantly from that of experiment 1 in which iron was used alone. At the dose of 1800 µg, vitamin A had a negative effect on iron absorption.Conclusion: High doses of vitamin A may cause lower serum iron levels, whereas a low dose favors iron absorption.Keywords: iron absorption, serum iron, vitamin A, oral iron, oral supplement

  18. Impaired myelination and reduced brain ferric iron in the mouse model of mucolipidosis IV.

    Science.gov (United States)

    Grishchuk, Yulia; Peña, Karina A; Coblentz, Jessica; King, Victoria E; Humphrey, Daniel M; Wang, Shirley L; Kiselyov, Kirill I; Slaugenhaupt, Susan A

    2015-12-01

    Mucolipidosis type IV (MLIV) is a lysosomal storage disease caused by mutations in the MCOLN1 gene, which encodes the lysosomal transient receptor potential ion channel mucolipin-1 (TRPML1). MLIV causes impaired motor and cognitive development, progressive loss of vision and gastric achlorhydria. How loss of TRPML1 leads to severe psychomotor retardation is currently unknown, and there is no therapy for MLIV. White matter abnormalities and a hypoplastic corpus callosum are the major hallmarks of MLIV brain pathology. Here, we report that loss of TRPML1 in mice results in developmental aberrations of brain myelination as a result of deficient maturation and loss of oligodendrocytes. Defective myelination is evident in Mcoln1(-/-) mice at postnatal day 10, an active stage of postnatal myelination in the mouse brain. Expression of mature oligodendrocyte markers is reduced in Mcoln1(-/-) mice at postnatal day 10 and remains lower throughout the course of the disease. We observed reduced Perls' staining in Mcoln1(-/-) brain, indicating lower levels of ferric iron. Total iron content in unperfused brain is not significantly different between Mcoln1(-/-) and wild-type littermate mice, suggesting that the observed maturation delay or loss of oligodendrocytes might be caused by impaired iron handling, rather than by global iron deficiency. Overall, these data emphasize a developmental rather than a degenerative disease course in MLIV, and suggest that there should be a stronger focus on oligodendrocyte maturation and survival to better understand MLIV pathogenesis and aid treatment development.

  19. The influence of intermittent hypobaric hypoxia on the brain iron metabolism in adult Sprague dawley rats

    Institute of Scientific and Technical Information of China (English)

    Wu Qiong; Li Yaru; Chang Yanzhong

    2015-01-01

    Objective:Iron is an essential element in all living organisms and is required as a cofactor for oxygen-binding proteins. Iron metabolism, oxygen homeostasis and erythropoiesis are consequently strongly inter-connected. In mammalian cells, exposure to a low-oxygen environment triggers a hypoxic response pathway cen-tered on the regulated expression of the hypoxia-inducible transcription factor ( HIF) . Hypoxia has been shown to increase the expression of a variety of proteins involved in iron homeostasis. However, little is known about brain iron metabolism after intermittent hypobaric hypoxia ( IHH) treatment. In this study, adult Sprague dawley ( SD) rats were treated with IHH for 28 days, 8h per day and then we detected iron homeostasis in different brain areas of SD rats. Results:The protein level of hippocampus transferrin receptor 1 ( TfR1 ) , divalent metal transporter 1 (DMT1) with IRE, DMT1 (-IRE), ferritin-H, iron regulatory protein (IRP) 2 and ceruloplasmin (CP) is ele-vated significantly while ferritin-L decreased. We have also found the down regulation of IRP1. We observe the same results in the cerebral cortex in the brain. Conclusions:We first discover that IHH has an influence on the brain iron homeostasis and the decreased ferritin-L corresponds to the down regulation of IRP1 indicating hypoxia can affect the expression of ferritin-L through IRE/IRP system. Although there is a marked increase in TfR1 ex-pression that would lead to the raised level of LIP in cells. It can finally result in the higher ROS which can damage the cells. The concerned mechanisms involved in it remain to be deliberated.

  20. Hunger for iron: the alternative siderophore iron scavenging systems in highly virulent Yersinia.

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    Alexander eRakin

    2012-11-01

    Full Text Available Low molecular weight siderophores are used by many living organisms to scavenge scarcely available ferric iron. Presence of at least a single siderophore-based iron acquisition system is usually acknowledged as a virulence-associated trait and a prerequisite to become an efficient and successful pathogen. Currently it is assumed that yersiniabactin (Ybt is the solely functional endogenous siderophore iron uptake system in highly virulent Yersinia (Yersinia pestis, Y. pseudotuberculosis and Y. enterocolitica biotype 1B. Genes responsible for biosynthesis, transport and regulation of the yersiniabactin (ybt production are clustered on a mobile genetic element, the High Pathogenicity Island (HPI that is responsible for broad dissemination of the ybt genes in Enterobacteriaceae. However, the ybt gene cluster is absent from nearly half of Y. pseudotuberculosis O3 isolates and epidemic Y. pseudotuberculosis O1 isolates responsible for the Far East Scarlet-like Fever. Several potential siderophore-mediated iron uptake gene clusters are documented in Yersinia genomes, however neither of them have been proven to be functional. It has been suggested that at least two siderophores alternative to Ybt may operate in the highly virulent Yersinia pestis / Y. pseudotuberculosis group, and are referred to as pseudochelin (Pch and yersiniachelin (Ych. Furthermore, most sporadic Y. pseudotuberculosis O1 strains possess gene clusters encoding all three iron scavenging systems. Thus, the Ybt system appears not to be the sole endogenous siderophore iron uptake system in the highly virulent yersiniae and may be efficiently substituted and / or supplemented by alternative iron scavenging systems.

  1. CAST-IRONS AT HIGH TEMPERATURES

    Directory of Open Access Journals (Sweden)

    A. N. Krutilin

    2008-01-01

    Full Text Available The results of investigations of physical-mechanical characteristics of cast iron slugs, received by semicontinuos way of casting, at temperatures from 850 up to 1100^ С are given. 

  2. Comparison of histological techniques to visualize iron in paraffin-embedded brain tissue of patients with Alzheimer's disease.

    Science.gov (United States)

    van Duijn, Sara; Nabuurs, Rob J A; van Duinen, Sjoerd G; Natté, Remco

    2013-11-01

    Better knowledge of the distribution of iron in the brains of Alzheimer's disease (AD) patients may facilitate the development of an in vivo magnetic resonance (MR) marker for AD and may cast light on the role of this potentially toxic molecule in the pathogenesis of AD. Several histological iron staining techniques have been used in the past but they have not been systematically tested for sensitivity and specificity. This article compares three histochemical techniques and ferritin immunohistochemistry to visualize iron in paraffin-embedded human AD brain tissue. The specificity of the histochemical techniques was tested by staining sections after iron extraction. Iron was demonstrated in the white matter, in layers IV/V of the frontal neocortex, in iron containing plaques, and in microglia. In our hands, these structures were best visualized using the Meguro iron stain, a method that has not been described for iron staining in human brain or AD in particular. Ferritin immunohistochemistry stained microglia and iron containing plaques similar to the Meguro method but was less intense in myelin-associated iron. The Meguro method is most suitable for identifying iron-positive structures in paraffin-embedded human AD brain tissue.

  3. [The nucleolus of the cell is the site of iron accumulation in the substantia nigra neurons of the human brain].

    Science.gov (United States)

    Sukhorukova, Ye G; Grigoriev, I P; Kolos, Ye A; Korzhenevskiy, D E

    2012-01-01

    Distribution of iron in the substantia nigra of the human brain (10 men and women aged 27-78 years) was studied using Perls' histochemical method. Iron ions were demonstrated in the nigral neuropil and melanin-containing neurons. For the first time the nuclei of some neurons were found to contain iron accumulations. The intranuclear iron inclusions correspond to the nucleolus according to their sharp outline and sizes. Detection of iron in the neuronal nucleolus may contribute to the understanding of mechanisms of iron neurotoxicity for nigral dopaminergic neurons.

  4. The Oral Iron Chelator, Deferasirox, Reverses the Age-Dependent Alterations in Iron and Amyloid-β Homeostasis in Rat Brain: Implications in the Therapy of Alzheimer's Disease.

    Science.gov (United States)

    Banerjee, Priyanjalee; Sahoo, Arghyadip; Anand, Shruti; Bir, Aritri; Chakrabarti, Sasanka

    2016-01-01

    The altered metabolism of iron impacts the brain function in multiple deleterious ways during normal aging as well as in Alzheimer's disease. We have shown in this study that chelatable iron accumulates in the aged rat brain along with overexpression of transferrin receptor 1 (TfR1) and ferritin, accompanied by significant alterations in amyloid-β (Aβ) peptide homeostasis in the aging brain, such as an increased production of the amyloid-β protein precursor, a decreased level of neprilysin, and increased accumulation of Aβ42. When aged rats are given daily the iron chelator, deferasirox, over a period of more than 4 months starting from the 18th month, the age-related accumulation of iron and overexpression of TfR1 and ferritin in the brain are significantly prevented. More interestingly, the chelator treatment also considerably reverses the altered Aβ peptide metabolism in the aging brain implying a significant role of iron in the latter phenomenon. Further, other results indicate that iron accumulation results in oxidative stress and the activation of NF-κB in the aged rat brain, which are also reversed by the deferasirox treatment. The analysis of the results together suggests that iron accumulation and oxidative stress interact at multiple levels that include transcriptional and post-transcriptional mechanisms to bring about changes in the expression levels of TfR1 and ferritin and also alterations in Aβ peptide metabolism in the aging rat brain. The efficacy of deferasirox in preventing age-related changes in iron and Aβ peptide metabolism in the aging brain, as shown here, has obvious therapeutic implications for Alzheimer's disease.

  5. Oxidative damage to rat brain in iron and copper overloads.

    Science.gov (United States)

    Musacco-Sebio, Rosario; Ferrarotti, Nidia; Saporito-Magriñá, Christian; Semprine, Jimena; Fuda, Julián; Torti, Horacio; Boveris, Alberto; Repetto, Marisa G

    2014-08-01

    This study reports on the acute brain toxicity of Fe and Cu in male Sprague-Dawley rats (200 g) that received 0 to 60 mg kg(-1) (ip) FeCl2 or CuSO4. Brain metal contents and time-responses were determined for rat survival, in situ brain chemiluminescence and phospholipid and protein oxidation products. Metal doses hyperbolically defined brain metal content. Rat survival was 91% and 60% after Fe and Cu overloads. Brain metal content increased from 35 to 114 μg of Fe per g and from 3.6 to 34 μg of Cu per g. Brain chemiluminescence (10 cps cm(-2)) increased 3 and 2 times after Fe and Cu overloads, with half maximal responses (C50) of 38 μg of Fe per g of brain and 15 μg of Cu per g of brain, and with half time responses (t1/2) of 12 h for Fe and 20 h for Cu. Phospholipid peroxidation increased by 56% and 31% with C50 of 40 μg of Fe per g and 20 μg of Cu per g and with t1/2 of 9 h and 14 h. Protein oxidation increased by 45% for Fe with a C50 of 40 μg of Fe per g and 18% for Cu with a C50 of 10 μg of Cu per g and a t1/2 of 12 h for both metals. Fe and Cu brain toxicities are likely mediated by Haber-Weiss type HO˙ formation with subsequent oxidative damage.

  6. Mitochondrial ferritin in the regulation of brain iron homeostasis and neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Guofen eGao

    2014-02-01

    Full Text Available Mitochondrial ferritin (FtMt is a novel iron-storage protein in mitochondria. Evidences have shown that FtMt is structurally and functionally similar to the cytosolic H-chain ferritin. It protects mitochondria from iron-induced oxidative damage presumably through sequestration of potentially harmful excess free iron. It also participates in the regulation of iron distribution between cytosol and mitochondrial contents. Unlike the ubiquitously expressed H-ferritin, FtMt is mainly expressed in testis and brain, which suggests its tissue-related roles. FtMt is involved in pathogenesis of neurodegenerative diseases, as its increased expression has been observed in Alzheimer’s disease, restless legs syndrome and Friedreich’s ataxia. Studies from our laboratory showed that in Alzheimer’s disease, FtMt overexpression attenuated the β-amyloid induced neurotoxicity, which on the other hand increased significantly when FtMt expression was knocked down. It is also found that, by maintaining mitochondrial iron homeostasis, FtMt could prevent 6-hydroxydopamine induced dopaminergic cell damage in Parkinson’s disease. These recent findings on FtMt regarding its functions in regulation of brain iron homeostasis and its protective role in pathogenesis of neurodegenerative diseases are summarized and reviewed.

  7. Increased brain iron coincides with early plaque formation in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Leskovjan, Andreana C; Kretlow, Ariane; Lanzirotti, Antonio; Barrea, Raul; Vogt, Stefan; Miller, Lisa M

    2011-03-01

    Elevated brain iron content, which has been observed in late-stage human Alzheimer's disease, is a potential target for early diagnosis. However, the time course for iron accumulation is currently unclear. Using the PSAPP mouse model of amyloid plaque formation, we conducted a time course study of metal ion content and distribution [iron (Fe), copper (Cu), and zinc (Zn)] in the cortex and hippocampus using X-ray fluorescence microscopy (XFM). We found that iron in the cortex was 34% higher than age-matched controls at an early stage, corresponding to the commencement of plaque formation. The elevated iron was not associated with the amyloid plaques. Interestingly, none of the metal ions were elevated in the amyloid plaques until the latest time point (56 weeks), where only the Zn content was significantly elevated by 38%. Since neuropathological changes in human Alzheimer's disease are presumed to occur years before the first cognitive symptoms appear, quantification of brain iron content could be a powerful marker for early diagnosis of Alzheimer's disease.

  8. Brain iron deposition in essential tremor: a quantitative 3-Tesla magnetic resonance imaging study.

    Science.gov (United States)

    Novellino, Fabiana; Cherubini, Andrea; Chiriaco, Carmelina; Morelli, Maurizio; Salsone, Maria; Arabia, Gennarina; Quattrone, Aldo

    2013-02-01

    Studies have demonstrated brain iron deposition in neurodegenerative disease and in normal aging. Data on this topic are lacking in essential tremor (ET). The aim of our study was to investigate brain iron content in patients with ET, using quantitative magnetic resonance imaging (MRI) T2*-relaxometry. We enrolled 24 patients with ET and 25 age-matched healthy controls. Subjects were examined using a 3T MRI scanner. The protocol included conventional MRI sequences and quantitative T2*-relaxometry. Whole-brain voxel-based analyses showed significant differences in T2* values in bilateral globus pallidus, substantia nigra, and in right dentate nucleus (P motor systems outside of the cerebellum/cerebellar pathway and, more specifically, of the globus pallidus. Copyright © 2012 Movement Disorders Society.

  9. Abnormal brain iron metabolism in Irp2 deficient mice is associated with mild neurological and behavioral impairments.

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    Kimberly B Zumbrennen-Bullough

    Full Text Available Iron Regulatory Protein 2 (Irp2, Ireb2 is a central regulator of cellular iron homeostasis in vertebrates. Two global knockout mouse models have been generated to explore the role of Irp2 in regulating iron metabolism. While both mouse models show that loss of Irp2 results in microcytic anemia and altered body iron distribution, discrepant results have drawn into question the role of Irp2 in regulating brain iron metabolism. One model shows that aged Irp2 deficient mice develop adult-onset progressive neurodegeneration that is associated with axonal degeneration and loss of Purkinje cells in the central nervous system. These mice show iron deposition in white matter tracts and oligodendrocyte soma throughout the brain. A contrasting model of global Irp2 deficiency shows no overt or pathological signs of neurodegeneration or brain iron accumulation, and display only mild motor coordination and balance deficits when challenged by specific tests. Explanations for conflicting findings in the severity of the clinical phenotype, brain iron accumulation and neuronal degeneration remain unclear. Here, we describe an additional mouse model of global Irp2 deficiency. Our aged Irp2-/- mice show marked iron deposition in white matter and in oligodendrocytes while iron content is significantly reduced in neurons. Ferritin and transferrin receptor 1 (TfR1, Tfrc, expression are increased and decreased, respectively, in the brain from Irp2-/- mice. These mice show impairments in locomotion, exploration, motor coordination/balance and nociception when assessed by neurological and behavioral tests, but lack overt signs of neurodegenerative disease. Ultrastructural studies of specific brain regions show no evidence of neurodegeneration. Our data suggest that Irp2 deficiency dysregulates brain iron metabolism causing cellular dysfunction that ultimately leads to mild neurological, behavioral and nociceptive impairments.

  10. New developments in high quality grey cast irons

    Institute of Scientific and Technical Information of China (English)

    Iulian Riposan; Mihai Chisamera; Stelian Stan

    2014-01-01

    The paper reviews original data obtained by the present authors, revealed in recent separate publications, describing speciifc procedures for high quality grey irons, and relfecting the forecast needs of the worldwide iron foundry industry. High power, medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries. This has resulted in low sulphur (1,500 °C), contributing to unfavourable conditions for graphite nucleation. Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidiifcation. The paper focused on two groups of grey cast irons and their speciifc problems: carbides and graphite morphology control in lower carbon equivalent high strength irons (CE=3.4%-3.8%), and austenite dendrite promotion in eutectic and slightly hypereutectic irons (CE=4.1%-4.5%), in order to increase their strength characteristics. There are 3 stages and 3 steps involving graphite formation, iron chemistry and iron processing that appear to be important. The concept in the present paper sustains a three-stage model for nucleating flake graphite [(Mn,X)S type nuclei]. There are three important groups of elements (deoxidizer,Mn/S, and inoculant) and three technological stages in electric melting of iron (superheat, pre-conditioning of base iron, ifnal inoculation). Attention is drawn to a control factor (%Mn) x (%S) ensuring it equals to 0.03- 0.06, accompanied by 0.005wt.%-0.010wt.% Al and/or Zr content in inoculated irons. It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic, acting as reinforcement for the eutectic cells. But, there is an accompanying possible negative influence on the characteristics of the (Mn,X)S type graphite nuclei (change the morphology of nuclei from polygonal compact to irregular polygonal, and therefore promote chill tendency in treated irons). A double addition (iron powder + inoculant

  11. New developments in high quality grey cast irons

    Directory of Open Access Journals (Sweden)

    Iulian Riposan

    2014-07-01

    Full Text Available The paper reviews original data obtained by the present authors, revealed in recent separate publications, describing specific procedures for high quality grey irons, and reflecting the forecast needs of the worldwide iron foundry industry. High power, medium frequency coreless induction furnaces are commonly used in electric melting grey iron foundries. This has resulted in low sulphur (1,500 °C, contributing to unfavourable conditions for graphite nucleation. Thin wall castings are increasingly produced by these electric melt shops with a risk of greater eutectic undercooling during solidification. The paper focused on two groups of grey cast irons and their specific problems: carbides and graphite morphology control in lower carbon equivalent high strength irons (CE=3.4%-3.8%, and austenite dendrite promotion in eutectic and slightly hypereutectic irons (CE=4.1%-4.5%, in order to increase their strength characteristics. There are 3 stages and 3 steps involving graphite formation, iron chemistry and iron processing that appear to be important. The concept in the present paper sustains a threestage model for nucleating flake graphite [(Mn,XS type nuclei]. There are three important groups of elements (deoxidizer, Mn/S, and inoculant and three technological stages in electric melting of iron (superheat, pre-conditioning of base iron, final inoculation. Attention is drawn to a control factor (%Mn x (%S ensuring it equals to 0.03 – 0.06, accompanied by 0.005wt.%–0.010wt.% Al and/or Zr content in inoculated irons. It was found that iron powder addition promotes austenite dendrite formation in eutectic and slightly eutectic, acting as reinforcement for the eutectic cells. But, there is an accompanying possible negative influence on the characteristics of the (Mn,XS type graphite nuclei (change the morphology of nuclei from polygonal compact to irregular polygonal, and therefore promote chill tendency in treated irons. A double addition (iron

  12. Iron

    Science.gov (United States)

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  13. Iron

    Science.gov (United States)

    ... of iron stored in the body become low, iron deficiency anemia sets in. Red blood cells become smaller and ... from the lungs throughout the body. Symptoms of iron deficiency anemia include tiredness and lack of energy, GI upset, ...

  14. Effect of cerebral amyloid angiopathy on brain iron, copper, and zinc in Alzheimer's disease.

    Science.gov (United States)

    Schrag, Matthew; Crofton, Andrew; Zabel, Matthew; Jiffry, Arshad; Kirsch, David; Dickson, April; Mao, Xiao Wen; Vinters, Harry V; Domaille, Dylan W; Chang, Christopher J; Kirsch, Wolff

    2011-01-01

    Cerebral amyloid angiopathy (CAA) is a vascular lesion associated with Alzheimer's disease (AD) present in up to 95% of AD patients and produces MRI-detectable microbleeds in many of these patients. It is possible that CAA-related microbleeding is a source of pathological iron in the AD brain. Because the homeostasis of copper, iron, and zinc are so intimately linked, we determined whether CAA contributes to changes in the brain levels of these metals. We obtained brain tissue from AD patients with severe CAA to compare to AD patients without evidence of vascular amyloid-β. Patients with severe CAA had significantly higher non-heme iron levels. Histologically, iron was deposited in the walls of large CAA-affected vessels. Zinc levels were significantly elevated in grey matter in both the CAA and non-CAA AD tissue, but no vascular staining was noted in CAA cases. Copper levels were decreased in both CAA and non-CAA AD tissues and copper was found to be prominently deposited on the vasculature in CAA. Together, these findings demonstrate that CAA is a significant variable affecting transition metals in AD.

  15. A novel approach to quantify different iron forms in ex-vivo human brain tissue

    Science.gov (United States)

    Kumar, Pravin; Bulk, Marjolein; Webb, Andrew; van der Weerd, Louise; Oosterkamp, Tjerk H.; Huber, Martina; Bossoni, Lucia

    2016-01-01

    We propose a novel combination of methods to study the physical properties of ferric ions and iron-oxide nanoparticles in post-mortem human brain, based on the combination of Electron Paramagnetic Resonance (EPR) and SQUID magnetometry. By means of EPR, we derive the concentration of the low molecular weight iron pool, as well as the product of its electron spin relaxation times. Additionally, by SQUID magnetometry we identify iron mineralization products ascribable to a magnetite/maghemite phase and a ferrihydrite (ferritin) phase. We further derive the concentration of magnetite/maghemite and of ferritin nanoparticles. To test out the new combined methodology, we studied brain tissue of an Alzheimer’s patient and a healthy control. Finally, we estimate that the size of the magnetite/maghemite nanoparticles, whose magnetic moments are blocked at room temperature, exceeds 40–50 nm, which is not compatible with the ferritin protein, the core of which is typically 6–8 nm. We believe that this methodology could be beneficial in the study of neurodegenerative diseases such as Alzheimer’s Disease which are characterized by abnormal iron accumulation in the brain. PMID:27941952

  16. A novel approach to quantify different iron forms in ex-vivo human brain tissue

    Science.gov (United States)

    Kumar, Pravin; Bulk, Marjolein; Webb, Andrew; van der Weerd, Louise; Oosterkamp, Tjerk H.; Huber, Martina; Bossoni, Lucia

    2016-12-01

    We propose a novel combination of methods to study the physical properties of ferric ions and iron-oxide nanoparticles in post-mortem human brain, based on the combination of Electron Paramagnetic Resonance (EPR) and SQUID magnetometry. By means of EPR, we derive the concentration of the low molecular weight iron pool, as well as the product of its electron spin relaxation times. Additionally, by SQUID magnetometry we identify iron mineralization products ascribable to a magnetite/maghemite phase and a ferrihydrite (ferritin) phase. We further derive the concentration of magnetite/maghemite and of ferritin nanoparticles. To test out the new combined methodology, we studied brain tissue of an Alzheimer’s patient and a healthy control. Finally, we estimate that the size of the magnetite/maghemite nanoparticles, whose magnetic moments are blocked at room temperature, exceeds 40-50 nm, which is not compatible with the ferritin protein, the core of which is typically 6-8 nm. We believe that this methodology could be beneficial in the study of neurodegenerative diseases such as Alzheimer’s Disease which are characterized by abnormal iron accumulation in the brain.

  17. Exogenous iron redistribution between brain and spleen after the administration of the 57Fe3O4 ferrofluid into the ventricle of the brain

    Science.gov (United States)

    Gabbasov, Raul; Polikarpov, Dmitry; Cherepanov, Valery; Chuev, Michael; Mischenko, Ilya; Loginiva, Nadezhda; Loseva, Elena; Nikitin, Maxim; Panchenko, Vladislav

    2017-04-01

    Iron clearance pathways after the injection of 57Fe3O4-based dextran-stabilized ferrofluid into the brain ventricles were studied by Mössbauer spectroscopy and histologically. The nanoparticles appeared in spleen tissues within 3 h after transcranial injection. We separated and independently estimated concentrations of iron encapsulated in nanoparticles and iron encapsulated in proteins in the all rat organs. It was found that the dextran coated initial nanoparticles of the ferrofluid disintegrated in the brain into separate superparamagnetic nanoparticles within a week after the injection.The nanoparticles completely exited from the brain in a few weeks. The exogenous iron appeared in the spleen in 3 h after the injection and remained in the spleen for more than month. The appearance of additional component in Mössbauer spectra of spleen samples revealed a fundamental difference in the mechanisms of processing of iron nanoparticles in this organ, which was also confirmed by histological examination.

  18. Quantitative Susceptibility Mapping Indicates a Disturbed Brain Iron Homeostasis in Neuromyelitis Optica – A Pilot Study

    Science.gov (United States)

    Granado, Vanessa; Rueda, Fernanda; Deistung, Andreas; Reichenbach, Juergen R.; Tukamoto, Gustavo; Gasparetto, Emerson Leandro; Schweser, Ferdinand

    2016-01-01

    Dysregulation of brain iron homeostasis is a hallmark of many neurodegenerative diseases and can be associated with oxidative stress. The objective of this study was to investigate brain iron in patients with Neuromyelitis Optica (NMO) using quantitative susceptibility mapping (QSM), a quantitative iron-sensitive MRI technique. 12 clinically confirmed NMO patients (6 female and 6 male; age 35.4y±14.2y) and 12 age- and sex-matched healthy controls (7 female and 5 male; age 33.9±11.3y) underwent MRI of the brain at 3 Tesla. Quantitative maps of the effective transverse relaxation rate (R2*) and magnetic susceptibility were calculated and a blinded ROI-based group comparison analysis was performed. Normality of the data and differences between patients and controls were tested by Kolmogorov-Smirnov and t-test, respectively. Correlation with age was studied using Spearman’s rank correlation and an ANCOVA-like analysis. Magnetic susceptibility values were decreased in the red nucleus (p0.95; between -15 and -22 ppb depending on reference region) with a trend toward increasing differences with age. R2* revealed significantly decreased relaxation in the optic radiations of five of the 12 patients (p<0.0001; -3.136±0.567 s-1). Decreased relaxation in the optic radiation is indicative for demyelination, which is in line with previous findings. Decreased magnetic susceptibility in the red nucleus is indicative for a lower brain iron concentration, a chemical redistribution of iron into less magnetic forms, or both. Further investigations are necessary to elucidate the pathological cause or consequence of this finding. PMID:27171423

  19. Impaired myelination and reduced brain ferric iron in the mouse model of mucolipidosis IV

    Directory of Open Access Journals (Sweden)

    Yulia Grishchuk

    2015-12-01

    Full Text Available Mucolipidosis type IV (MLIV is a lysosomal storage disease caused by mutations in the MCOLN1 gene, which encodes the lysosomal transient receptor potential ion channel mucolipin-1 (TRPML1. MLIV causes impaired motor and cognitive development, progressive loss of vision and gastric achlorhydria. How loss of TRPML1 leads to severe psychomotor retardation is currently unknown, and there is no therapy for MLIV. White matter abnormalities and a hypoplastic corpus callosum are the major hallmarks of MLIV brain pathology. Here, we report that loss of TRPML1 in mice results in developmental aberrations of brain myelination as a result of deficient maturation and loss of oligodendrocytes. Defective myelination is evident in Mcoln1−/− mice at postnatal day 10, an active stage of postnatal myelination in the mouse brain. Expression of mature oligodendrocyte markers is reduced in Mcoln1−/− mice at postnatal day 10 and remains lower throughout the course of the disease. We observed reduced Perls' staining in Mcoln1−/− brain, indicating lower levels of ferric iron. Total iron content in unperfused brain is not significantly different between Mcoln1−/− and wild-type littermate mice, suggesting that the observed maturation delay or loss of oligodendrocytes might be caused by impaired iron handling, rather than by global iron deficiency. Overall, these data emphasize a developmental rather than a degenerative disease course in MLIV, and suggest that there should be a stronger focus on oligodendrocyte maturation and survival to better understand MLIV pathogenesis and aid treatment development.

  20. High-temperature corrosion of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Lab., IL (United States); Cho, W.D. [Utah Univ., Salt Lake City, UT (United States)

    1994-04-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve their engineering ductility. This paper describes results from an ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne involves thermogravimetric analyses of alloys exposed to environments that simulate coal gasification and coal combustion. Corrosion experiments were conducted to determine the effect of gas flow rate and different levels of HCl at a gas temperature of 650 C on three heats of aluminide material, namely, FA 61, FA 129, and FAX. In addition, specimens of Type 316 stainless steel with an overlay alloying of iron aluminide were prepared by electrospark deposition and tested for their corrosion resistance. Detailed microstructural evaluations of tested specimens were performed. Results are used to assess the corrosion resistance of various iron aluminides for service in fossil energy systems that utilize coal as a feedstock.

  1. High protein and iron-folate crackers supplementation on the iron status of pregnant women

    Directory of Open Access Journals (Sweden)

    Faisal Anwar

    2003-12-01

    Full Text Available Previous studies have revealed that several factors influenced the relatively low success of iron supplementation for pregnant women. The factors included poor distribution, low coverage and compliance, as well as low absorption. The aim of this study is to measure the iron status of pregnant women after consuming crackers containing fish powder and iron-folate. This study was carried out in the Purworejo district (Central Java from February through October 2002. Using a randomized controlled trial (RCT design, 70 pregnant women in their second-third month of pregnancy were recruited, and divided into two groups. Ten women dropped out during the study. The first group consisted of 28 women were given protein – iron enriched crackers (PIEC group, while the second group of 32 women were given iron–enriched crackers (IEC group for a total of 12 weeks. The results showed that the hemoglobin (Hb levels and serum transferrin receptors (sTfR of both groups were increased. Serum ferritins (SF of both groups were decreased. At the end of the study, the increase in Hb and sTfR levels between the two groups were significantly different, while the decrease in SF was not significantly different. Animal protein from fish powder tended to improve absorption of non-heme iron among pregnant women, resulting in improved Hb and sTfR levels. (Med J Indones 2003; 12: 243-6Keywords: pregnant women, anemia, iron deficiency, high protein crackers

  2. Neutrophilic iron oxidizers adapted to highly oxic environments

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    indicate that neutrophilic iron oxidizers in highly oxic environments like drinking water treatment systems can be abundant (5 E+04 to 7 E+05 cells per gram of wet sand material). It was furthermore observed that the diversity of the cultivated dominant iron oxidizers differs substantially from those...... carbon) while oxygen (O2) is the electron acceptor provided during the aeration process. Numerous previous studies have described neutrophilic iron oxidizers as a bacterial guild with a special niche preference, especially the transition zone between aerobic and anoxic regions, where abiotic chemical...

  3. High efficiency iron electrode and additives for use in rechargeable iron-based batteries

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Sri R.; Prakash, G. K. Surya; Aniszfeld, Robert; Manohar, Aswin; Malkhandi, Souradip; Yang, Bo

    2017-02-21

    An iron electrode and a method of manufacturing an iron electrode for use in an iron-based rechargeable battery are disclosed. In one embodiment, the iron electrode includes carbonyl iron powder and one of a metal sulfide additive or metal oxide additive selected from the group of metals consisting of bismuth, lead, mercury, indium, gallium, and tin for suppressing hydrogen evolution at the iron electrode during charging of the iron-based rechargeable battery. An iron-air rechargeable battery including an iron electrode comprising carbonyl iron is also disclosed, as is an iron-air battery wherein at least one of the iron electrode and the electrolyte includes an organosulfur additive.

  4. Nitrogen Atom Transfer From High Valent Iron Nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael D. [New Mexico State Univ., Las Cruces, NM (United States); Smith, Jeremy M. [Indiana Univ., Bloomington, IN (United States)

    2015-10-14

    This report describes the synthesis and reactions of high valent iron nitrides. Organonitrogen compounds such as aziridines are useful species for organic synthesis, but there are few efficient methods for their synthesis. Using iron nitrides to catalytically access these species may allow for their synthesis in an energy-and atom-efficient manner. We have developed a new ligand framework to achieve these goals as well as providing a method for inducing previously unknown reactivity.

  5. Late-Onset Neurodegeneration with Brain Iron Accumulation with Diffusion Tensor Magnetic Resonance Imaging

    OpenAIRE

    Syed Omar Shah; Hasit Mehta; Robert Fekete

    2012-01-01

    Introduction: Neuroferritinopathy is an autosomal dominant neurodegenerative disorder that includes a movement disorder, cognitive decline, and characteristic findings on brain magnetic resonance imaging (MRI) due to abnormal iron deposition. Here, we present a late-onset case, along with diffusion tensor imaging (DTI). Case Presentation: We report the case of a 74-year-old Caucasian female with no significant past medical history who presented for evaluation of orofacial dyskinesia, suspecte...

  6. Differences on Brain Connectivity in Adulthood Are Present in Subjects with Iron Deficiency Anemia in Infancy

    Science.gov (United States)

    Algarin, Cecilia; Karunakaran, Keerthana Deepti; Reyes, Sussanne; Morales, Cristian; Lozoff, Betsy; Peirano, Patricio; Biswal, Bharat

    2017-01-01

    Iron deficiency continues to be the most prevalent micronutrient deficit worldwide. Since iron is involved in several processes including myelination, dopamine neurotransmission and neuronal metabolism, the presence of iron deficiency anemia (IDA) in infancy relates to long-lasting neurofunctional effects. There is scarce data regarding whether these effects would extend to former iron deficient anemic human adults. Resting state functional magnetic resonance imaging (fMRI) is a novel technique to explore patterns of functional connectivity. Default Mode Network (DMN), one of the resting state networks, is deeply involved in memory, social cognition and self-referential processes. The four core regions consistently identified in the DMN are the medial prefrontal cortex, posterior cingulate/retrosplenial cortex and left and right inferior parietal cortex. Therefore to investigate the DMN in former iron deficient anemic adults is a particularly useful approach to elucidate de long term effects on functional brain. We conducted this research to explore the connection between IDA in infancy and altered patterns of resting state brain functional networks in young adults. Resting-state fMRI studies were performed to 31 participants that belong to a follow-up study since infancy. Of them, 14 participants were former iron deficient anemic in infancy and 17 were controls, with mean age of 21.5 years (±1.5) and 54.8% were males. Resting-state fMRI protocol was used and the data was analyzed using the seed based connectivity statistical analysis to assess the DMN. We found that compared to controls, former iron deficient anemic subjects showed posterior DMN decreased connectivity to the left posterior cingulate cortex (PCC), whereas they exhibited increased anterior DMN connectivity to the right PCC. Differences between groups were also apparent in the left medial frontal gyrus, with former iron deficient anemic participants having increased connectivity with areas included

  7. Eltrombopag, a thrombopoietin mimetic, crosses the blood-brain barrier and impairs iron-dependent hippocampal neuron dendrite development.

    Science.gov (United States)

    Bastian, T W; Duck, K A; Michalopoulos, G C; Chen, M J; Liu, Z-J; Connor, J R; Lanier, L M; Sola-Visner, M C; Georgieff, M K

    2017-03-01

    Essentials Potential neurodevelopmental side effects of thrombopoietin mimetics need to be considered. The effects of eltrombopag (ELT) on neuronal iron status and dendrite development were assessed. ELT crosses the blood-brain barrier and causes iron deficiency in developing neurons. ELT blunts dendrite maturation, indicating a need for more safety studies before neonatal use.

  8. Superparamagnetic iron oxide nanoparticles conjugated with epidermal growth factor (SPION–EGF for targeting brain tumors

    Directory of Open Access Journals (Sweden)

    Shevtsov MA

    2014-01-01

    Full Text Available Maxim A Shevtsov,1,2 Boris P Nikolaev,3 Ludmila Y Yakovleva,3 Yaroslav Y Marchenko,3 Anatolii V Dobrodumov,4 Anastasiya L Mikhrina,5 Marina G Martynova,1 Olga A Bystrova,1 Igor V Yakovenko,2 Alexander M Ischenko31Institute of Cytology of the Russian Academy of Sciences (RAS, 2AL Polenov Russian Scientific Research Institute of Neurosurgery, 3Research Institute of Highly Pure Biopreparations, 4Institute of Macromolecular Compounds of the Russian Academy of Sciences (RAS, 5IM Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (RAS, St Petersburg, RussiaAbstract: Superparamagnetic iron oxide nanoparticles (SPIONs conjugated with recombinant human epidermal growth factor (SPION–EGF were studied as a potential agent for magnetic resonance imaging contrast enhancement of malignant brain tumors. Synthesized conjugates were characterized by transmission electron microscopy, dynamic light scattering, and nuclear magnetic resonance relaxometry. The interaction of SPION–EGF conjugates with cells was analyzed in a C6 glioma cell culture. The distribution of the nanoparticles and their accumulation in tumors were assessed by magnetic resonance imaging in an orthotopic model of C6 gliomas. SPION–EGF nanosuspensions had the properties of a negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION–EGF nanoparticles showed high intracellular incorporation and the absence of a toxic influence on C6 cell viability and proliferation. Intravenous administration of SPION–EGF conjugates in animals provided receptor-mediated targeted delivery across the blood–brain barrier and tumor retention of the nanoparticles; this was more efficient than with unconjugated SPIONs. The accumulation of conjugates in the glioma was revealed as hypotensive zones on T2-weighted images with a twofold reduction in T2 relaxation time in comparison to unconjugated SPIONs (P<0.001. SPION

  9. High pressure Moessbauer spectroscopy of perovskite iron oxide

    CERN Document Server

    Nasu, S; Morimoto, S; Kawakami, T; Kuzushita, K; Takano, M

    2003-01-01

    High-pressure sup 5 sup 7 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO sub 3 , CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 O sub 3. The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO sub 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

  10. Defective lipid metabolism in neurodegeneration with brain iron accumulation (NBIA) syndromes: not only a matter of iron.

    Science.gov (United States)

    Colombelli, Cristina; Aoun, Manar; Tiranti, Valeria

    2015-01-01

    Neurodegeneration with brain iron accumulation (NBIA) is a group of devastating and life threatening rare diseases. Adult and early-onset NBIA syndromes are inherited as X-chromosomal, autosomal dominant or recessive traits and several genes have been identified as responsible for these disorders. Among the identified disease genes, only two code for proteins directly involved in iron metabolism while the remaining NBIA genes encode proteins with a wide variety of functions ranging from fatty acid metabolism and autophagy to still unknown activities. It is becoming increasingly evident that many neurodegenerative diseases are associated with metabolic dysfunction that often involves altered lipid metabolism. This is not surprising since neurons have a peculiar and heterogeneous lipid composition critical for the development and correct functioning of the nervous system. This review will focus on specific NBIA forms, namely PKAN, CoPAN, PLAN, FAHN and MPAN, which display an interesting link between neurodegeneration and alteration of phospholipids and sphingolipids metabolism, mitochondrial morphology and membrane remodelling.

  11. Iron

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Moen, I W; Mandrup-Poulsen, T

    2014-01-01

    The interest in the role of ferrous iron in diabetes pathophysiology has been revived by recent evidence of iron as an important determinant of pancreatic islet inflammation and as a biomarker of diabetes risk and mortality. The iron metabolism in the β-cell is complex. Excess free iron is toxic......, but at the same time, iron is required for normal β-cell function and thereby glucose homeostasis. In the pathogenesis of diabetes, iron generates reactive oxygen species (ROS) by participating in the Fenton chemistry, which can induce oxidative damage and apoptosis. The aim of this review is to present...... and discuss recent evidence, suggesting that iron is a key pathogenic factor in both type 1 and type 2 diabetes with a focus on inflammatory pathways. Pro-inflammatory cytokine-induced β-cell death is not fully understood, but may include iron-induced ROS formation resulting in dedifferentiation by activation...

  12. Prevalence of Iron Deficiency and Iron Deficiency Anemia in High-School Girl Students of Yazd

    Directory of Open Access Journals (Sweden)

    M Noori Shadkam

    2009-07-01

    Full Text Available Introduction: It is generally assumed that 50% of the cases of anemia are due to iron deficiency. The most severe consequence of iron depletion is iron deficiency anemia (IDA, and it is still considered the most common nutrition deficiency worldwide. The main risk factors for IDA include: inadequate iron intake, impaired absorption or transport, physiologic losses associated with chronological or reproductive age, or acute or chronic blood loss, parasite infections such as hookworms, acute and chronic infections, including malaria, cancer, tuberculosis, HIV and other micronutrient deficiencies, including vitamins A and B12, folate, riboflavin, and copper deficiency. Methods: This work as a cross-sectional study was done in 2007-2008 in Yazd. Two hundred girls who participated in the study were selected randomly from eight girl high schools. Five ml venous blood was collected for determination of serum ferritin and cell blood count (CBC. Serum ferritin was determined by using ECLIA method and CBC by cell counter SYSMEX KX21N. Iron deficiency was defined as having serum ferritin values below 12 μ/l. Anemia was defined as having Hemoglobin levels below12 g/dl. Iron-deficiency anemia was considered to be the combination of both. Results: The3 mean ageyears and body mass index (kg/m2 were 15.19±0.7years and 21.5±4.2, respectively. Distribution in the 14, 15 and 16 years and more age groups were 13, 58.5 and 28.5 percent, respectively. Mean of Hemoglobin(g/dl, Hematocrit(%, MCV (fl, MCH (pg, MCHC (g/dl and ferritin(μ/l were 12.8±0.9, 38.9±3.0, 80.7±4.3, 26.6±1.8, 33.2±3.6 and 23±18.2, respectively. Of the total, 13.5% were anemic, 68% of which had Iron Deficiency Anemia (9.3% of the total. Iron deficiency was present in 34.7% of the population under study. Conclusion: According to world health organization criteria, anemia is a mild public health problem in this region, but iron deficiency is a significant problem and suitable measures for

  13. Development of instant noodles from high-iron rice and iron-fortified rice flour

    Directory of Open Access Journals (Sweden)

    Suparat Reungmaneepaitoon

    2008-08-01

    Full Text Available Instant high-iron noodles, prepared from wheat flour and high iron brown rice flour, were developed. Three varieties of rice flour, Suphan Buri 90 (SB, Homnin 313 (HW and Homnin 1000 (HP, containing amylose content of 30.40, 19.10 and 15.74% (w/w and iron content of 1.24, 2.04 and 2.22 (mg/100 g respectively, were used to replace wheat flour for instant fried noodle production. To determine the physicochemical properties and acceptability of instant fried noodles,different percentages (30, 40, 50% (w/w of each rice flour sample were used. The instant fried noodles were fortified with ferrous sulphate at levels of 0, 32, 64% iron of RDI per serving. Increasing amount of iron content in the mixtures decreased the L* value, b* value and increased a* value for the color of the instant fried noodle with brown rice flour. The texture characteristic of the noodles with 30, 40, 50% replacement with each variety of brown rice flour were significantly different from those of wheat noodle. Tensile force of the noodles decreased from 11.57±1.30 g to 6.38±1.45 g (SB, 8.36±0.96 g to 5.71±0.57 g (HP and 10.09±1.20 g to 5.46±1.31 g (HW as the rice flour content increased from 30 to 50%. The sensoryacceptability of the noodles made from each variety of 30% brown rice flour fortified with 32% iron of RDI had higher preference scores for elasticity, firmness, color and overall acceptability, than those with 64% iron of RDI. Instant fried noodles with HW and HP brown rice flour were subjected to consumer test using 100 rural primary school children. The frequency percent of the acceptability scores of the noodle with HP and HW were 88 and 84% respectively. Shelf life studyrevealed that the developed products were still acceptable up to 4 months. These products were claimed to be high iron noodle.

  14. Age-associated changes of brain copper, iron, and zinc in Alzheimer's disease and dementia with Lewy bodies.

    Science.gov (United States)

    Graham, Stewart F; Nasaruddin, Muhammad Bin; Carey, Manus; Holscher, Christian; McGuinness, Bernadette; Kehoe, Patrick G; Love, Seth; Passmore, Peter; Elliott, Christopher T; Meharg, Andrew A; Green, Brian D

    2014-01-01

    Disease-, age-, and gender-associated changes in brain copper, iron, and zinc were assessed in postmortem neocortical tissue (Brodmann area 7) from patients with moderate Alzheimer's disease (AD) (n = 14), severe AD (n = 28), dementia with Lewy bodies (n = 15), and normal age-matched control subjects (n = 26). Copper was lower (20%; p iron higher (10-16%; p iron, suggesting gradual age-associated decline of these metals in healthy non-cognitively impaired individuals. Zinc was unaffected in any disease pathologies and no age-associated changes were apparent. Age-associated changes in brain elements warrant further investigation.

  15. Both immanently high active iron contents and increased root ferrous uptake in response to low iron stress contribute to the iron deficiency tolerance in Malus xiaojinensis.

    Science.gov (United States)

    Zha, Qian; Wang, Yi; Zhang, Xin-Zhong; Han, Zhen-Hai

    2014-01-01

    To better understand the mechanism of low-iron stress tolerance in Malus xiaojinensis, the differences in physiological parameters and gene expression between an iron deficiency-sensitive species, Malus baccata, and an iron deficiency-tolerant species, M. xiaojinensis were investigated under low-iron (4 μM Fe) conditions. Under iron sufficient conditions, the expressions of iron uptake- and transport-related genes, i.e. FIT1, IRT1, CS1, FRD3 and NRMAP1, and the immanent leaf and root active iron contents were higher in M. xiaojinensis than those in M. baccata. However, on the first three days of low iron stress, the rhizospheric pH decreased and the root ferric chelate reductase (FCR) activity and the expression of ferrous uptake- and iron transport-related genes in the roots increased significantly only in M. xiaojinensis. Leaf chlorosis occurred on the 3rd and the 9th day after low-iron treatment in M. baccata and M. xiaojinensis, respectively. The expression of iron relocalization-related genes, such as NAS1, FRD3 and NRMAP3, increased after the 5th or 6th day of low iron stress in leaves of M. xiaojinensis, whereas the expression of NAS1, FRD3 and NRMAP3 in the leaves of M. baccata increased immediately after the onset of low iron treatment. Conclusively, the relative high active iron contents caused by the immanently active root ferrous uptake and the increased root ferrous uptake in response to low iron stress were the dominant mechanisms for the tolerance to iron deficiency in M. xiaojinensis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Shock Melting Temperature of Initially Porous Iron and Indication for Melting Curve of Iron at High Pressures

    Institute of Scientific and Technical Information of China (English)

    LI Xi-Jun; ZHANG Dai-Yu; LIU Fu-Sheng; JING Fu-Qian

    2004-01-01

    The melting curve ofiron is crucial for modelling of the earth's internal heat structures and to understand melting of solids at high pressures. However, the measured melting temperatures of iron at high pressures are disparate so far. We measured the shocked interface (porous iron/sapphire window) temperatures of a kind of porous iron. By using a model for shock temperature measurement [High Pressures Res. 2 (1990) 159] and the previous results of sound velocity measurements [Chin. Phys. Lett. 18 (2001) 852], we determine the melting temperatures of iron at shock compression high pressures of 145 and 171 Gpa. They are consistent with the results reported by other shock compression experiments. Based on the possible different melting mechanisms of iron in diamond anvil cell and in shock compression, the corrected melting temperatures of iron at high pressures become more consistent.

  17. Increased brain iron coincides with early plaque formation in a mouse model of Alzheimer’s disease

    OpenAIRE

    Leskovjan, Andreana C.; Kretlow, Ariane; Lanzirotti, Antonio; Barrea, Raul; Vogt, Stefan; Miller, Lisa M.

    2010-01-01

    Elevated brain iron content, which has been observed in late stage human Alzheimer’s disease, is a potential target for early diagnosis. However, the time course for iron accumulation is currently unclear. Using the PSAPP mouse model of amyloid plaque formation, we conducted a time course study of metal ion content and distribution [iron (Fe), copper (Cu), and zinc (Zn)] in the cortex and hippocampus using X-ray fluorescence microscopy (XFM). We found that iron in the cortex was 34% higher th...

  18. High-strength cast irons used for manufacturing parts of vaz passenger cars

    Science.gov (United States)

    Kitaigora, N. I.

    1996-10-01

    Methods for solving problems arising in the production of high-strength cast iron with stable properties and structure are considered. Results of introduction of new grades of high-strength cast iron instead of malleable cast iron and camshaft cast iron in the Volzhskii Automobile Plant are described.

  19. Mononuclear Nonheme Iron(III)-Iodosylarene and High-Valent Iron-Oxo Complexes in Olefin Epoxidation Reactions.

    Science.gov (United States)

    Wang, Bin; Lee, Yong-Min; Seo, Mi Sook; Nam, Wonwoo

    2015-09-28

    High-spin iron(III)-iodosylarene complexes are highly reactive in the epoxidation of olefins, in which epoxides are formed as the major products with high stereospecificity and enantioselectivity. The reactivity of the iron(III)-iodosylarene intermediates is much greater than that of the corresponding iron(IV)-oxo complex in these reactions. The iron(III)-iodosylarene species-not high-valent iron(IV)-oxo and iron(V)-oxo species-are also shown to be the active oxidants in catalytic olefin epoxidation reactions. The present results are discussed in light of the long-standing controversy on the one oxidant versus multiple oxidants hypothesis in oxidation reactions.

  20. Mitochondria: A crossroads for lipid metabolism defect in neurodegeneration with brain iron accumulation diseases.

    Science.gov (United States)

    Aoun, Manar; Tiranti, Valeria

    2015-06-01

    Neurodegeneration with brain iron accumulation (NBIA) comprises a group of brain iron deposition syndromes that lead to mixed extrapyramidal features and progressive dementia. Exact pathologic mechanism of iron deposition in NBIA remains unknown. However, it is becoming increasingly evident that many neurodegenerative diseases are hallmarked by metabolic dysfunction that often involves altered lipid profile. Among the identified disease genes, four encode for proteins localized in mitochondria, which are directly or indirectly implicated in lipid metabolism: PANK2, CoASY, PLA2G6 and C19orf12. Mutations in PANK2 and CoASY, both implicated in CoA biosynthesis that acts as a fatty acyl carrier, lead, respectively, to PKAN and CoPAN forms of NBIA. Mutations in PLA2G6, which plays a key role in the biosynthesis and remodeling of membrane phospholipids including cardiolipin, lead to PLAN. Mutations in C19orf12 lead to MPAN, a syndrome similar to that caused by mutations in PANK2 and PLA2G6. Although the function of C19orf12 is largely unknown, experimental data suggest its implication in mitochondrial homeostasis and lipid metabolism. Altogether, the identified mutated proteins localized in mitochondria and associated with different NBIA forms support the concept that dysfunctions in mitochondria and lipid metabolism play a crucial role in the pathogenesis of NBIA. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies.

  1. Bioleaching of marmatite in high concentration of iron

    Institute of Scientific and Technical Information of China (English)

    邱冠周; 吴伯增; 覃文庆; 蓝卓越

    2002-01-01

    Bioleaching of marmatite with a culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans in high concentration of iron was studied, the results show that the zinc leaching rate of the mixed culture is faster than that of the sole Thiobacillus ferrooxidans, the increasing iron concentration in leaching solution enhances the zinc leaching rate. The SEM analysis indicates that the chemical leaching residues is covered with porous solid layer of elemental sulfur, while elemental sulfur is not found in the bacterial leaching residues. The primary role of bacteria in bioleaching of sphalerite is to oxidize the chemical leaching products of ferrous ion and elemental sulfur, thus the indirect mechanism prevails in the bioleaching of marmatite.

  2. Neutrophilic iron oxidizers adapted to highly oxic environments

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen;

    of iron oxidizing bacterial in the highly oxic environments found in typical rapid sand filters. The neutrophilic FeOB were enriched by the Fe2+/O2 opposing gradient technique and quantified by MPN methodology. Diversity fingerprints of the enrichment cultures were obtained with a 16S rRNA targeted DGGE...... oxidation of iron would be retarded. For that reason, no attempts have been documented to describe the density and diversity of iron oxidizing bacteria (FeOB) in oxic neutrophilic environments. Under low temperatures (5 to 10°C) conditions, as typically found in groundwater, extremely low rates of chemical...... technique, and dominant bands were isolated and sequenced for identification of dominant enrichment members. Enrichment were microscopically examined via CSLM in combination with FeOB specific or generic cytostains to verify enrichments, check cell morphologies and quantify cell densities. Our results...

  3. Engineered Cooling Process for High Strength Ductile Iron Castings

    Science.gov (United States)

    Lekakh, Simon N.; Mikhailov, Anthony; Kramer, Joseph

    Professor Stefanescu contributed fundamentally to the science of solidification and microstructural evolutions in ductile irons. In this article, the possibility of development of high strength ductile iron by applying an engineered cooling process after casting early shake out from the sand mold was explored. The structures in industrial ductile iron were experimentally simulated using a computer controlled heating/cooling device. CFD modeling was used for process simulation and an experimental bench scale system was developed. The process concept was experimentally verified by producing cast plates with 25 mm wall thickness. The tensile strength was increased from 550 MPa to 1000 MPa in as-cast condition without the need for alloying and heat treatment. The possible practical applications were discussed.

  4. Oxidation resistant iron and nickel alloys for high temperature use

    Science.gov (United States)

    Hill, V. L.; Misra, S. K.; Wheaton, H. L.

    1970-01-01

    Iron-base and nickel-base alloys exhibit good oxidation resistance and improved ductility with addition of small amounts of yttrium, tantalum /or hafnium/, and thorium. They can be used in applications above the operating temperatures of the superalloys, if high strength materials are not required.

  5. Late-Onset Neurodegeneration with Brain Iron Accumulation with Diffusion Tensor Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Syed Omar Shah

    2012-12-01

    Full Text Available Introduction: Neuroferritinopathy is an autosomal dominant neurodegenerative disorder that includes a movement disorder, cognitive decline, and characteristic findings on brain magnetic resonance imaging (MRI due to abnormal iron deposition. Here, we present a late-onset case, along with diffusion tensor imaging (DTI. Case Presentation: We report the case of a 74-year-old Caucasian female with no significant past medical history who presented for evaluation of orofacial dyskinesia, suspected to be edentulous dyskinesia given her history of ill-fitting dentures. She had also developed slowly progressive dysarthria, dysphagia, visual hallucinations as well as stereotypic movements of her hands and feet. Results: The eye-of-the-tiger sign was demonstrated on T2 MRI. Increased fractional anisotropy and T2 hypointensity were observed in the periphery of the globus pallidus, putamen, substantia nigra, and dentate nucleus. T2 hyperintensity was present in the medial dentate nucleus and central globus pallidus. Discussion: The pallidal MRI findings were more typical of pantothenate kinase-associated neurodegeneration (PKAN, but given additional dentate and putamenal involvement, lack of retinopathy, and advanced age of onset, PKAN was less likely. Although the patient’s ferritin levels were within low normal range, her clinical and imaging features led to a diagnosis of neuroferritinopathy. Conclusion: Neurodegeneration with brain iron accumulation (NBIA is a rare cause of orofacial dyskinesia. DTI MRI can confirm abnormal iron deposition. The location of abnormal iron deposits helps in differentiating NBIA subtypes. Degeneration of the dentate and globus pallidus may occur via an analogous process given their similar T2 and DTI MRI appearance.

  6. Quantitative Susceptibility Mapping Suggests Altered Brain Iron in Premanifest Huntington Disease.

    Science.gov (United States)

    van Bergen, J M G; Hua, J; Unschuld, P G; Lim, I A L; Jones, C K; Margolis, R L; Ross, C A; van Zijl, P C M; Li, X

    2016-05-01

    In patients with premanifest (nonsymptomatic) and advanced Huntington disease, changes in brain iron levels in the basal ganglia have been previously reported, especially in the striatum. Quantitative susceptibility mapping by using MR phase imaging allows in vivo measurements of tissue magnetic susceptibility, which has been shown to correlate well with iron levels in brain gray matter and is believed to be more specific than other imaging-based iron measures. The purpose of this study was to investigate the use of magnetic susceptibility as a biomarker of disease progression. Fifteen subjects with premanifest Huntington disease and 16 age-matched healthy controls were scanned at 7T. Magnetic susceptibility, effective relaxation, and tissue volume in deep gray matter structures were quantified and compared with genetic and clinical measures. Subjects with premanifest Huntington disease showed significantly higher susceptibility values in the caudate nucleus, putamen, and globus pallidus, indicating increased iron levels in these structures. Significant decreases in magnetic susceptibility were found in the substantia nigra and hippocampus. In addition, significant volume loss (atrophy) and an increase effective relaxation were observed in the caudate nucleus and putamen. Susceptibility values in the caudate nucleus and putamen were found to be inversely correlated with structure volumes and directly correlated with the genetic burdens, represented by cytosine-adenine-guanine repeat age-product-scaled scores. The significant magnetic susceptibility differences between subjects with premanifest Huntington disease and controls and their correlation with genetic burden scores indicate the potential use of magnetic susceptibility as a biomarker of disease progression in premanifest Huntington disease. © 2016 by American Journal of Neuroradiology.

  7. New findings about iron oxide nanoparticles and their different effects on murine primary brain cells

    Directory of Open Access Journals (Sweden)

    Neubert J

    2015-03-01

    Full Text Available Jenni Neubert,1 Susanne Wagner,2 Jürgen Kiwit,3 Anja U Bräuer,1,* Jana Glumm1,3,* 1Institute of Cell Biology and Neurobiology, Center for Anatomy, 2Institute for Radiology, Charité-Universitaetsmedizin Berlin, 3Clinic for Neurosurgery, HELIOS Klinikum Berlin-Buch, Berlin, Germany *These authors contributed equally to this work Abstract: The physicochemical properties of superparamagnetic iron oxide nanoparticles (SPIOs enable their application in the diagnostics and therapy of central nervous system diseases. However, since crucial information regarding side effects of particle–cell interactions within the central nervous system is still lacking, we investigated the influence of novel very small iron oxide particles or the clinically approved ferucarbotran or ferumoxytol on the vitality and morphology of brain cells. We exposed primary cell cultures of microglia and hippocampal neurons, as well as neuron–glia cocultures to varying concentrations of SPIOs for 6 and/or 24 hours, respectively. Here, we show that SPIO accumulation by microglia and subsequent morphological alterations strongly depend on the respective nanoparticle type. Microglial viability was severely compromised by high SPIO concentrations, except in the case of ferumoxytol. While ferumoxytol did not cause immediate microglial death, it induced severe morphological alterations and increased degeneration of primary neurons. Additionally, primary neurons clearly degenerated after very small iron oxide particle and ferucarbotran exposure. In neuron–glia cocultures, SPIOs rather stimulated the outgrowth of neuronal processes in a concentration- and particle-dependent manner. We conclude that the influence of SPIOs on brain cells not only depends on the particle type but also on the physiological system they are applied to. Keywords: microglia, hippocampal neurons, degeneration, morphology, nanoparticles 

  8. High dose intravenous iron, mineral homeostasis and intact FGF23 in normal and uremic rats

    DEFF Research Database (Denmark)

    Gravesen, Eva; Hofman-Bang, Jacob; Mace, Maria L.

    2013-01-01

    High iron load might have a number of toxic effects in the organism. Recently intravenous (iv) iron has been proposed to induce elevation of fibroblast growth factor 23 (FGF23), hypophosphatemia and osteomalacia in iron deficient subjects. High levels of FGF23 are associated with increased......, iron isomaltoside 1000 (IIM) and ferric carboxymaltose (FCM), on plasma levels of FGF23 and phosphate was examined in normal and uremic iron repleted rats....

  9. Study on Metallized Reduction and Magnetic Separation of Iron from Fine Particles of High Iron Bauxite Ore

    Science.gov (United States)

    Liu, Zheng-Gen; Chu, Man-Sheng; Wang, Zheng; Zhao, Wei; Tang, Jue

    2017-01-01

    High iron bauxite ore is a typical unmanageable polyparagenetic resource and owns high comprehensive utilization value. Separation of iron from fine particles of high iron bauxite ore by the process of metallized reduction and magnetic dressing was researched systemically. The effect of magnetic field intensity, reduction temperature, reduction time, mole ratio of fixed carbon to reducible oxygen (FC/O) and ore particles size on separation indexes was researched. The results show that, with the conditions of reduction temperature of 1,400 °C, reduction time of 180 min, FC/O of 2.0, ore particle size of -2.0 mm and magnetic field intensity of 40 KA/m, about 89.24 % of the iron could be removed from high iron bauxite ore as metallic iron. Meanwhile, 86.09 % of the aluminum is stayed in non-magnetic fraction as alumina. However, the formation of hercynite (FeAl2O4) limits the reduction rate of iron oxides to metallic iron. The lower reduction conditions and higher recovery ratio of iron could be achieved with adopting ore-coal composite agglomerates or adding catalyst.

  10. Iron-Restricted Diet Affects Brain Ferritin Levels, Dopamine Metabolism and Cellular Prion Protein in a Region-Specific Manner

    Directory of Open Access Journals (Sweden)

    Jessica M. V. Pino

    2017-05-01

    Full Text Available Iron is an essential micronutrient for several physiological functions, including the regulation of dopaminergic neurotransmission. On the other hand, both iron, and dopamine can affect the folding and aggregation of proteins related with neurodegenerative diseases, such as cellular prion protein (PrPC and α-synuclein, suggesting that deregulation of iron homeostasis and the consequential disturbance of dopamine metabolism can be a risk factor for conformational diseases. These proteins, in turn, are known to participate in the regulation of iron and dopamine metabolism. In this study, we evaluated the effects of dietary iron restriction on brain ferritin levels, dopamine metabolism, and the expression levels of PrPC and α-synuclein. To achieve this goal, C57BL/6 mice were fed with iron restricted diet (IR or with normal diet (CTL for 1 month. IR reduced iron and ferritin levels in liver. Ferritin reduction was also observed in the hippocampus. However, in the striatum of IR group, ferritin level was increased, suggesting that under iron-deficient condition, each brain area might acquire distinct capacity to store iron. Increased lipid peroxidation was observed only in hippocampus of IR group, where ferritin level was reduced. IR also generated discrete results regarding dopamine metabolism of distinct brain regions: in striatum, the level of dopamine metabolites (DOPAC and HVA was reduced; in prefrontal cortex, only HVA was increased along with the enhanced MAO-A activity; in hippocampus, no alterations were observed. PrPC levels were increased only in the striatum of IR group, where ferritin level was also increased. PrPC is known to play roles in iron uptake. Thus, the increase of PrPC in striatum of IR group might be related to the increased ferritin level. α-synuclein was not altered in any regions. Abnormal accumulation of ferritin, increased MAO-A activity or lipid peroxidation are molecular features observed in several neurological

  11. Comparison of Histological Techniques to Visualize Iron in Paraffin-embedded Brain Tissue of Patients with Alzheimer’s Disease

    OpenAIRE

    van Duijn, Sara; Rob J A Nabuurs; van Duinen, Sjoerd G.; Natté, Remco

    2013-01-01

    Better knowledge of the distribution of iron in the brains of Alzheimer’s disease (AD) patients may facilitate the development of an in vivo magnetic resonance (MR) marker for AD and may cast light on the role of this potentially toxic molecule in the pathogenesis of AD. Several histological iron staining techniques have been used in the past but they have not been systematically tested for sensitivity and specificity. This article compares three histochemical techniques and ferritin immunohi...

  12. Electrical Resistivity and Thermodynamic Properties of Iron Under High Pressure

    Science.gov (United States)

    Hieu, Ho Khac; Hai, Tran Thi; Hong, Nguyen Thi; Sang, Ngo Dinh; Tuyen, Nguyen Viet

    2017-03-01

    In this work, the electrical resistivity and thermodynamic properties of iron under high pressure have been investigated by using the semi-empirical approach. The recently well-established Grüneisen parameter expressions have been applied to derive the Debye frequency and temperature under compression. Using these results combined with the Bloch-Grüneisen law, the resistivity of iron has also been determined up to Earth's core pressures. We show that the electrical resistivity diminished gradually with pressure and saturates at high pressure. Our model gives low electrical resistivity values which are in agreement with the recent experimental measurements. The low resistivity may be attributed to the well-known resistivity saturation effect at high temperature, which was not considered in earlier models of core conductivity.

  13. Low and high frequency fatigue tests of nodular cast irons

    Directory of Open Access Journals (Sweden)

    A. Vaško

    2017-01-01

    Full Text Available The paper deals with the comparison of fatigue properties of nodular cast iron at low and high frequency cyclic loading. The specimens from three melts of nodular cast iron with different microstructure and mechanical properties were used for experiments. Fatigue tests were carried out at low and high frequency sinusoidal cyclic push-pull loading (stress ratio R = –1 at ambient temperature (T = 20 ± 5 °C. Low frequency fatigue tests were carried out using the fatigue experimental machine Zwick/Roell Amsler 150HFP 5100 at frequency f ≈ 120 Hz; high frequency fatigue tests were carried out using the ultrasonic fatigue testing device KAUP-ZU at frequency f ≈ 20 kHz.

  14. Brain iron accumulation in unexplained fetal and infant death victims with smoker mothers-The possible involvement of maternal methemoglobinemia

    Directory of Open Access Journals (Sweden)

    Corna Melissa F

    2011-07-01

    Full Text Available Abstract Background Iron is involved in important vital functions as an essential component of the oxygen-transporting heme mechanism. In this study we aimed to evaluate whether oxidative metabolites from maternal cigarette smoke could affect iron homeostasis in the brain of victims of sudden unexplained fetal and infant death, maybe through the induction of maternal hemoglobin damage, such as in case of methemoglobinemia. Methods Histochemical investigations by Prussian blue reaction were made on brain nonheme ferric iron deposits, gaining detailed data on their localization in the brainstem and cerebellum of victims of sudden death and controls. The Gless and Marsland's modification of Bielschowsky's was used to identify neuronal cell bodies and neurofilaments. Results Our approach highlighted accumulations of blue granulations, indicative of iron positive reactions, in the brainstem and cerebellum of 33% of victims of sudden death and in none of the control group. The modified Bielschowsky's method confirmed that the cells with iron accumulations were neuronal cells. Conclusions We propose that the free iron deposition in the brain of sudden fetal and infant death victims could be a catabolic product of maternal methemoglobinemia, a biomarker of oxidative stress likely due to nicotine absorption.

  15. Alteration of the coenzyme A biosynthetic pathway in neurodegeneration with brain iron accumulation syndromes.

    Science.gov (United States)

    Venco, Paola; Dusi, Sabrina; Valletta, Lorella; Tiranti, Valeria

    2014-08-01

    NBIA (neurodegeneration with brain iron accumulation) comprises a heterogeneous group of neurodegenerative diseases having as a common denominator, iron overload in specific brain areas, mainly basal ganglia and globus pallidus. In the past decade a bunch of disease genes have been identified, but NBIA pathomechanisms are still not completely clear. PKAN (pantothenate kinase-associated neurodegeneration), an autosomal recessive disorder with progressive impairment of movement, vision and cognition, is the most common form of NBIA. It is caused by mutations in the PANK2 (pantothenate kinase 2) gene, coding for a mitochondrial enzyme that phosphorylates vitamin B5 in the first reaction of the CoA (coenzyme A) biosynthetic pathway. A distinct form of NBIA, denominated CoPAN (CoA synthase protein-associated neurodegeneration), is caused by mutations in the CoASY (CoA synthase) gene coding for a bifunctional mitochondrial enzyme, which catalyses the final steps of CoA biosynthesis. These two inborn errors of CoA metabolism further support the concept that dysfunctions in CoA synthesis may play a crucial role in the pathogenesis of NBIA.

  16. Quantitative Susceptibility Mapping Reveals an Association between Brain Iron Load and Depression Severity

    Directory of Open Access Journals (Sweden)

    Shun Yao

    2017-08-01

    Full Text Available Previous studies have detected abnormal serum ferritin levels in patients with depression; however, the results have been inconsistent. This study used quantitative susceptibility mapping (QSM for the first time to examine brain iron concentration in depressed patients and evaluated whether it is related to severity. We included three groups of age- and gender-matched participants: 30 patients with mild-moderate depression (MD, 14 patients with major depression disorder (MDD and 20 control subjects. All participants underwent MR scans with a 3D gradient-echo sequence reconstructing for QSM and performed the 17-item Hamilton Depression Rating Scale (HDRS test. In MDD, the susceptibility value in the bilateral putamen was significantly increased compared with MD or control subjects. In addition, a significant difference was also observed in the left thalamus in MDD patients compared with controls. However, the susceptibility values did not differ between MD patients and controls. The susceptibility values positively correlated with the severity of depression as indicated by the HDRS scores. Our results provide evidence that brain iron deposition may be associated with depression and may even be a biomarker for investigating the pathophysiological mechanism of depression.

  17. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.; Maziasz, P.J.

    1996-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  18. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.; Marrero-Santos, Y.; Maziasz, P.J.

    1995-06-01

    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile density due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications, despite their excellent corrosion properties. Improvements in room temperature tensile ductility have been realized mainly through alloying effects, changes in thermomechanical processing to control microstructure, and by control of the specimen`s surface condition. Ductilities of 10-20% and tensile yield strengths as high as 500 MPa have been reported. In terms of creep-rupture strength, small additions of Mo, Nb, and Zr have produced significant improvements, but at the expense of weldability and room-temperature tensile ductility. Recently an alloy containing these additions, designated FA-180, was shown to exhibit a creep-rupture life of over 2000 h after a heat treatment of 1 h at 1150{degrees}C. This study presents the results of creep-rupture tests at various test temperatures and stresses and discusses the results as part of our effort to understand the strengthening mechanisms involved with heat treatment at 1150{degrees}C.

  19. Optimizing hardenability of high chromium white cast iron

    Institute of Scientific and Technical Information of China (English)

    SU Ying-long; LI Dan; ZHANG Xue-kun

    2006-01-01

    The formulas proposed by J. Dodd and J. L. Parks for calculating the hardenability of high-Cr white cast iron under continuous cooling condition was recommended. For broader application, some supplements were made to the formula. Through tests on the half-cooling time of typical castings, the compositions of ideal alloys were precisely designed using the Dodd's formula. Hardness testing of heat-treated castings showed that the designed compositions were correct. The application of castings demonstrated excellent abrasion resistance.

  20. High iron accumulation in hair and nail of people living in iron affected areas of Assam, India.

    Science.gov (United States)

    Chaturvedi, Richa; Banerjee, Saumen; Chattopadhyay, Pronobesh; Bhattacharjee, Chira R; Raul, Prasanta; Borah, Kusum

    2014-12-01

    Human populace of Assam, India repeatedly exposed to high concentration of iron in groundwater results in adverse health effects like hemochromatosis, liver cirrhosis and siderosis. In the present study, human hair and nail analysis were carried out to establish a possible relationship between iron toxicity and its deposition among the residents. Nail and hair iron concentrations ranged from 28.2 to 1046μgg(-1) (n=114) and 26.5-838 (n=108)μgg(-1) levels, respectively, among all the study participants. The iron content of the groundwater (421-5340μgL(-1)) (n=64) used for drinking purposes was positively correlated with both nail (r=0.788, piron concentrations. Age- and sex-matched controls corresponding to each group were selected from population residing in other parts of the country where groundwater does not have excess iron. All the study groups included population drinking iron-contaminated water above the WHO/BIS limit (>300µgL(-1)) for 5 years (Group 1), for more than 5-10 years (Group 2) and for more than 10 years (Group 3). Results suggested that the participants consuming groundwater exceeding the WHO limit of iron had significantly more iron accumulation than those using groundwater containing ≤300μgL(-1) iron (piron in the nail samples than the hair samples in all the study groups (piron concentration and the residence time of the participants (pIron levels in the male participants were significantly higher than the female participants in the present study (piron exposure through drinking water and adverse effects to the human in the areas where iron concentration is high.

  1. Cellular distribution of ferric iron, ferritin, transferrin and divalent metal transporter 1 (DMT1) in substantia nigra and basal ganglia of normal and β2-microglobulin deficient mouse brain

    DEFF Research Database (Denmark)

    Moos, Torben; Trinder, D.; Morgan, E.H.

    2000-01-01

    beta-2-microglobulin, blood-brain barrier, gene knock out, iron, neurodegenerative disorders, oxidative damage, subthalamic nucleus......beta-2-microglobulin, blood-brain barrier, gene knock out, iron, neurodegenerative disorders, oxidative damage, subthalamic nucleus...

  2. Elastic properties of {alpha}-iron at high temperatures by high-pressure neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, S; Cornelius, A L; Philippe, J [IMPMC, Universite P and M Curie, 4 Place Jussieu, C115, 75252 Paris (France); Straessle, Th; Pomjakushin, V, E-mail: Stefan.Klotz@impmc.upmc.fr [Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

    2011-02-09

    We present high pressure-high temperature neutron diffraction data of {alpha}-iron in the 0-8 GPa and 300-550 K range. We find the isochors of {alpha}-iron strictly parallel to those of {epsilon}-iron, except at high P/T when the {alpha}-{gamma}-{epsilon} triple point to the non-magnetic {gamma}- and {epsilon}-phases is approached. This gives evidence for magnetoelastic effects in {alpha}-iron at high P/T. The measurements have been made possible by the use of a cell which enables neutron diffraction by external heating in the 0-10 GPa range and to at least 550 K. The technique should have numerous applications in research on condensed matter using neutrons.

  3. Mixed State and High Effective Utilization of Pilbara Blending Iron Ore Powder%Mixed State and High Effective Utilization of Pilbara Blending Iron Ore Powder

    Institute of Scientific and Technical Information of China (English)

    CAO Yong-guo; WU Sheng-li; HAN Hong-liang; WANG Hong-wei; XUE Fang; LIU Xiao-qin

    2011-01-01

    Pilbara blending iron ore powder (PB powder) is blending ores with good and poor quality iron ores, so how to use PB power effectively is a problem. The self-characteristics of PB powder and its single-components were studied respectively such as the macroscopic properties, microscopic properties, and high-temperature properties the behavior and effect in the sintering were mastered. Then based on the new ore-proportioning idea of iron ores sintering characteristics complementary, the principles on the effective use of PB powder were discussed, and was fur ther validated through the sintering pot test and industrial production. The results show that PB powder is composed of three kinds of iron ore, and the sintering characteristics of different iron ores are obviously discrepant. With the ore-proportioning optimization based on the iron ores sintering characteristics complementary, the proportion of PB iron ore powder can be increased to more than 45 %.

  4. High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue

    Science.gov (United States)

    Collingwood, J. F.; Mikhaylova, A.; Davidson, M. R.; Batich, C.; Streit, W. J.; Eskin, T.; Terry, J.; Barrea, R.; Underhill, R. S.; Dobson, J.

    2005-01-01

    Fluorescence mapping and microfocus X-ray absorption spectroscopy are used to detect, locate and identify iron biominerals and other inorganic metal accumulations in neurodegenerative brain tissue at sub-cellular resolution (reviewed. Synchrotron X-rays are used to map tissue sections for metals of interest, and XANES and XAFS are used to characterise anomalous concentrations of the metals in-situ so that they can be correlated with tissue structures and disease pathology. Iron anomalies associated with biogenic magnetite, ferritin and haemoglobin are located and identified in an avian tissue model with a pixel resolution ~5 microns. Subsequent studies include brain tissue sections from transgenic Huntington's mice, and the first high-resolution mapping and identification of iron biominerals in human Alzheimer's and control autopsy brain tissue. Technical developments include use of microfocus diffraction to obtain structural information about biominerals in-situ, and depositing sample location grids by lithography for the location of anomalies by conventional microscopy. The combined techniques provide a breakthrough in the study of both intra- and extra-cellular iron compounds and related metals in tissue. The information to be gained from this approach has implications for future diagnosis and treatment of neurodegeneration, and for our understanding of the mechanisms involved.

  5. Influence of Mechanical Activation on Acid Leaching Dephosphorization of High-phosphorus Iron Ore Concentrates

    Institute of Scientific and Technical Information of China (English)

    De-qing ZHU; Hao WANG; Jian PAN; Cong-cong YANG

    2016-01-01

    High pressure roll grinding (HPRG)and ball milling were compared to investigate the influence of me-chanical activation on the acid leaching dephosphorization of a high-phosphorus iron ore concentrate,which was man-ufactured through magnetizing roasting-magnetic separation of high-phosphorus oolitic iron ores.The results indica-ted that when high-phosphorus iron ore concentrates containing 54·92 mass% iron and 0·76 mass% phosphorus were directly processed through acid leaching,iron ore concentrates containing 55·74 mass% iron and 0·33 mass%phosphorus with an iron recovery of 84·64% and dephosphorization of 63·79% were obtained.When high-phosphor-us iron ore concentrates activated by ball milling were processed by acid leaching,iron ore concentrates containing 56·03 mass% iron and 0·21 mass% phosphorus with an iron recovery of 85·65% and dephosphorization of 77·49%were obtained.Meanwhile,when high-phosphorus iron ore concentrates activated by HPRG were processed by acid leaching,iron ore concentrates containing 58·02 mass% iron and 0·10 mass% phosphorus were obtained,with the iron recovery reaching 88·42% and the dephosphorization rate reaching 88·99%.Mechanistic studies demonstrated that ball milling can reduce the particle size,demonstrating a prominent reunion phenomenon.In contrast,HPRG pretreatment contributes to the formation of more cracks within the particles and selective dissociation of iron and P bearing minerals,which can provide the favorable kinetic conditions to accelerate the solid-liquid reaction rate.As such,the crystal structure is destroyed and the surface energy of mineral particles is strengthened by mechanical ac-tivation,further strengthening the dephosphorization.

  6. Sound Velocities of Iron-Nickel and Iron-Nickel-Silicon Alloys at High Pressure

    Science.gov (United States)

    Miller, R. A.; Jackson, J. M.; Sturhahn, W.; Zhao, J.; Murphy, C. A.

    2014-12-01

    Seismological and cosmochemical studies suggest Earth's core is primarily composed of iron with ~5 to 10 wt% nickel and some light elements [e.g. 1]. To date, the concentration of nickel and the amount and identity of light elements remain poorly constrained due in part to the difficulty of conducting experimental measurements at core conditions. The vibrational properties of a variety iron alloys paired with seismic observations can help better constrain the composition of the core. We directly measured the partial phonon density of states of bcc- and hcp-structured Fe0.9Ni0.1 and Fe0.85Ni0.1Si0.05 at high pressures. The samples were compressed using a panoramic diamond anvil cell. A subset of the experiments were conducted using neon as a pressure transmitting medium. Measurements of high statistical quality were performed with nuclear resonant inelastic x-ray scattering (NRIXS) at sector 3-ID-B of the Advanced Photon Source [2, 3, 4]. The unit cell volume of each sample was determined at each compression point with in-situ x-ray diffraction at sector 3-ID-B before and after each NRIXS measurement. The Debye, compressional, and shear sound velocities were determined from the low energy region of the partial phonon density of states paired with the volume measurements. We will present partial phonon density of states and sound velocities for Fe0.9Ni0.1 and Fe0.85Ni0.1Si0.05 at high-pressure and compare with those of pure iron. References: [1] McDonough, W.F. (2004): Compositional Model for the Earth's Core. Elsevier Ltd., Oxford. [2] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Melting and thermal pressure of hcp-Fe from the phonon density of states, Phys. Earth Planet. Int., doi:10.1016/j.pepi.2011.07.001. [3] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Grüneisen parameter of hcp-Fe to 171 GPa, Geophys. Res. Lett., doi:10.1029/2011GL049531. [4] Murphy, C.A., J.M. Jackson, and W. Sturhahn (2013): Experimental constraints on the

  7. Nicotianamine synthase overexpression positively modulates iron homeostasis-related genes in high iron rice

    Directory of Open Access Journals (Sweden)

    Meng eWang

    2013-05-01

    Full Text Available Nearly one-third of the world population, mostly women and children, suffer from iron malnutrition and its consequences, such as anemia or impaired mental development. Biofortification of rice, which is a staple crop for nearly half of the world’s population, can significantly contribute in alleviating iron deficiency. NFP rice (transgenic rice expressing nicotianamine synthase, ferritin and phytase genes has a more than six-fold increase in iron content in polished rice grains, resulting from the synergistic action of nicotianamine synthase (NAS and ferritin transgenes. We investigated iron homeostasis in NFP plants by analyzing the expression of 28 endogenous rice genes known to be involved in the homeostasis of iron and other metals, in iron-deficient and iron-sufficient conditions. RNA was collected from different tissues (roots, flag leaves, grains and at three developmental stages during grain filling. NFP plants showed increased sensitivity to iron-deficiency conditions and changes in the expression of endogenous genes involved in nicotianamine (NA metabolism, in comparison to their non-transgenic siblings. Elevated transcript levels were detected in NFP plants for several iron transporters. In contrast, expression of OsYSL2, which encodes a member of Yellow Stripe-like protein family, and a transporter of the NA-Fe(II complex was reduced in NFP plants under low iron conditions, indicating that expression of OsYSL2 is regulated by the endogenous iron status. Expression of the transgenes did not significantly affect overall iron homeostasis in NFP plants, which establishes the engineered push-pull mechanism as a suitable strategy to increase rice endosperm iron content.

  8. Nicotianamine synthase overexpression positively modulates iron homeostasis-related genes in high iron rice.

    Science.gov (United States)

    Wang, Meng; Gruissem, Wilhelm; Bhullar, Navreet K

    2013-01-01

    Nearly one-third of the world population, mostly women and children, suffer from iron malnutrition and its consequences, such as anemia or impaired mental development. Biofortification of rice, which is a staple crop for nearly half of the world's population, can significantly contribute in alleviating iron deficiency. NFP rice (transgenic rice expressing nicotianamine synthase, ferritin and phytase genes) has a more than six-fold increase in iron content in polished rice grains, resulting from the synergistic action of nicotianamine synthase (NAS) and ferritin transgenes. We investigated iron homeostasis in NFP plants by analyzing the expression of 28 endogenous rice genes known to be involved in the homeostasis of iron and other metals, in iron-deficient and iron-sufficient conditions. RNA was collected from different tissues (roots, flag leaves, grains) and at three developmental stages during grain filling. NFP plants showed increased sensitivity to iron-deficiency conditions and changes in the expression of endogenous genes involved in nicotianamine (NA) metabolism, in comparison to their non-transgenic siblings (NTS). Elevated transcript levels were detected in NFP plants for several iron transporters. In contrast, expression of OsYSL2, which encodes a member of yellow stripe like protein family, and a transporter of the NA-Fe(II) complex was reduced in NFP plants under low iron conditions, indicating that expression of OsYSL2 is regulated by the endogenous iron status. Expression of the transgenes did not significantly affect overall iron homeostasis in NFP plants, which establishes the engineered push-pull mechanism as a suitable strategy to increase rice endosperm iron content.

  9. High Affinity Iron Permease is Required for Virulence of Rhizopus oryzae

    Science.gov (United States)

    Rhizopus oryzae is the most common cause of mucormycosis. Clinical and animal model data clearly demonstrate that the presence of elevated available serum iron predisposes the host to develop mucormycosis. The high affinity iron permease gene (rFTR1) is required for R. oryzae iron transport in iro...

  10. High-dielectric losses in stabilized {gamma}-iron/graphite nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.F. [Dalian University of Technology, School of Materials Science and Engineering, Dalian, Liaoning (China); National Research Council of Canada, Industrial Materials Institute, Boucherville, Quebec (Canada); Guan, P.F. [Tohoku University, World Premier International Research Center, Advanced Institute for Materials Research, Sendai (Japan); Medwig, J. [National Research Council of Canada, Industrial Materials Institute, Boucherville, Quebec (Canada); Dong, X.L. [Dalian University of Technology, School of Materials Science and Engineering, Dalian, Liaoning (China)

    2012-03-15

    {gamma}-iron and {gamma}-iron/graphite nanoparticles were synthesized by a non-equilibrium cooling arc-discharge method. Experimental extinction spectra exhibit unexpected dielectric resonance of {gamma}-iron nanoparticles at the microwave frequency, presenting the first metallic nanostructure of the high-dielectric loss. We further construct a multi-dielectric loss structure, with the enhanced dielectric loss factor of 0.7-0.9, by encapsulating the {gamma}-iron into onion-like graphite nanoshells. (orig.)

  11. Structural Changes Under Heat Treatment of High-Strength Cast Iron with Globular Graphite

    Science.gov (United States)

    Tsukanov, V. V.; Ziza, A. I.; Mikhailov, M. S.; Tsyganko, L. K.; Shandyba, G. A.

    2016-11-01

    High-strength cast iron of grade VCh50 with globular graphite is studied after isothermal quenching in the bainitic and martensitic ranges. The mechanical properties of the iron and the hardness of its structural components are determined. The fine structure of the iron with bainitic and martensitic matrix is studied. The effect of the tempering temperature after the isothermal quenching on the hardness and structure of the iron is estimated.

  12. Simultaneous Recovery of Iron and Phosphorus from a High-Phosphorus Oolitic Iron Ore to Prepare Fe-P Alloy for High-Phosphorus Steel Production

    Science.gov (United States)

    Yang, Congcong; Zhu, Deqing; Pan, Jian; Lu, Liming

    2017-09-01

    Unlike previous dephosphorization studies, the present work complies with a concept to recover phosphorus within the utilization of high-phosphorus oolitic iron ores to prepare Fe -P alloy for high-phosphorus steel production. Simultaneous enrichment of iron and phosphorus can be achieved by directly alloying the high-phosphorus oolitic iron ore at high reduction temperatures (≥1623 K). Neither fluxes nor other special additives need to be used. Consequently, the phosphorus element migrates from original apatite to the slag phase with the elevating temperature from 1323 K to 1473 K, and it further moves into metallic iron and forms Fe3P at 1623 K. A metalized iron -phosphorus alloy with assaying of 96.51% iron and 2.03% phosphorus content was obtained at 1623 K for 10 min at corresponding iron and phosphorus recovery rates of 97.50% and 64.51%, respectively. This process exhibits high economic efficiency and is practicable as a stepping-stone for the efficient and direct utilization of high-phosphorus iron ore resources.

  13. Biological Signatures of Brain Damage Associated with High Serum Ferritin Levels in Patients with Acute Ischemic Stroke and Thrombolytic Treatment

    Directory of Open Access Journals (Sweden)

    Mónica Millán

    2008-01-01

    Full Text Available Background and purpose: Increased body iron stores have been related to greater oxidative stress and brain injury in clinical and experimental cerebral ischemia and reperfusion. We aimed to investigate the biological signatures of excitotoxicity, inflammation and blood brain barrier disruption potentially associated with high serum ferritin levels-related damage in acute stroke patients treated with i.v. t-PA.

  14. Dementia means number of things - the overlap of neurodegeneration with brain iron accumulation (NBIA) and Alzheimer changes: an autopsy case.

    Science.gov (United States)

    Dziewulska, Dorota; Domitrz, Izabela; Domzał-Stryga, Anna

    2010-01-01

    In humans overlap between various neurodegenerative disorders is a well known phenomenon. We reported a case of a 77-year-old woman with parkinsonism, dystonia, psychiatric symptoms and progressing dementia misdiagnosed at the age of 51 years as Parkinson's disease. Histopathological examination of the patient's brain performed 26 years after the disease onset revealed numerous axonal spheroids and iron deposits in structures of the nigro-pallido-striatal system that enabled to diagnose neurodegeneration with brain iron accumulation (NBIA) (former Hallervorden-Spatz syndrome), and changes characteristic for Alzheimer's disease (AD). NBIA is a group of rare clinically and genetically heterogeneous diseases of the extrapyramidal system which common feature is abnormal iron storage in the basal ganglia. Disturbed iron metabolism is also one of the hypothetical patho-mechanisms of AD. A coexistence of morphological changes characteristic for AD and NBIA in our patient suggests that similar molecular mechanisms may be involved in pathogenesis of various neurodegenerative processes, especially in disorders with iron dyshomeostasis. This case contributes also to the increasing evidence of NBIA heterogeneity.

  15. Alzheimer's disease therapeutics targeted to the control of amyloid precursor protein translation: maintenance of brain iron homeostasis.

    Science.gov (United States)

    Bandyopadhyay, Sanghamitra; Rogers, Jack T

    2014-04-15

    The neurotoxicity of amyloid beta (Aβ), a major cleavage product of the amyloid precursor protein (APP), is enhanced by iron, as found in the amyloid plaques of Alzheimer's disease (AD) patients. By contrast, the long-known neuroprotective activity of APP is evident after α-secretase cleavage of the precursor to release sAPPα, and depends on the iron export actions of APP itself. The latter underlie its neurotrophic and protective effects in facilitating the homeostatic actions of ferroportin mediated-iron export. Thus APP-dependent iron export may alleviate oxidative stress by minimizing labile iron thus protecting neurons from iron overload during stroke and hemorrhage. Consistent with this, altered phosphorylation of iron-regulatory protein-1 (IRP1) and its signaling processes play a critical role in modulating APP translation via the 5' untranslated region (5'UTR) of its transcript. The APP 5'UTR region encodes a functional iron-responsive element (IRE) RNA stem loop that represents a potential target for modulating APP production. Targeted regulation of APP gene expression via the modulation of 5'UTR sequence function represents a novel approach for the potential treatment of AD since altering APP translation can be used to improve both the protective brain iron balance and provide anti-amyloid efficacy. Approved drugs including paroxetine and desferrioxamine and several novel compounds have been identified that suppress abnormal metal-promoted Aβ accumulation with a subset of these acting via APP 5'UTR-dependent mechanisms to modulate APP translation and cleavage to generate the non-toxic sAPPα.

  16. Blood-brain barrier flux of aluminum, manganese, iron and other metals suspected to contribute to metal-induced neurodegeneration.

    Science.gov (United States)

    Yokel, Robert A

    2006-11-01

    The etiology of many neurodegenerative diseases has been only partly attributed to acquired traits, suggesting environmental factors may also contribute. Metal dyshomeostasis causes or has been implicated in many neurodegenerative diseases. Metal flux across the blood-brain barrier (the primary route of brain metal uptake) and the choroid plexuses as well as sensory nerve metal uptake from the nasal cavity are reviewed. Transporters that have been described at the blood-brain barrier are listed to illustrate the extensive possibilities for moving substances into and out of the brain. The controversial role of aluminum in Alzheimer's disease, evidence suggesting brain aluminum uptake by transferrin-receptor mediated endocytosis and of aluminum citrate by system Xc;{-} and an organic anion transporter, and results suggesting transporter-mediated aluminum brain efflux are reviewed. The ability of manganese to produce a parkinsonism-like syndrome, evidence suggesting manganese uptake by transferrin- and non-transferrin-dependent mechanisms which may include store-operated calcium channels, and the lack of transporter-mediated manganese brain efflux, are discussed. The evidence for transferrin-dependent and independent mechanisms of brain iron uptake is presented. The copper transporters, ATP7A and ATP7B, and their roles in Menkes and Wilson's diseases, are summarized. Brain zinc uptake is facilitated by L- and D-histidine, but a transporter, if involved, has not been identified. Brain lead uptake may involve a non-energy-dependent process, store-operated calcium channels, and/or an ATP-dependent calcium pump. Methyl mercury can form a complex with L-cysteine that mimics methionine, enabling its transport by the L system. The putative roles of zinc transporters, ZnT and Zip, in regulating brain zinc are discussed. Although brain uptake mechanisms for some metals have been identified, metal efflux from the brain has received little attention, preventing integration of

  17. [Application of solid sampling graphite furnace atomic absorption spectrophotometry to mensuration of brain iron content in rats].

    Science.gov (United States)

    Zhang, Nan; Sheng, Qing-hai; Shi, Zhen-hua; Zhang, Zhi-guo; Duan, Xiang-lin; Chang, Yan-zhong

    2009-04-01

    In the present study, the authors performed the solid sampling and detected the iron levels in cortex, hippocampus and striatum of rat brain by GFAAS. The authors' results showed that there are no remarkable difference between the data obtained by solid sampling graphite furnace atomic absorption and liquid sampling graphite furnace atomic absorption. Compared to liquid sampling graphite furnace atomic absorption, the sample pre-treatment stage was obviously simplified, the cost was reduced significantly, and the time was shortened significantly in the solid sampling GFAAS. This study will be beneficial to the mensuration of iron content in micro-tissue of animal by solid sampling GFASS.

  18. Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2014-02-01

    Full Text Available Genetic improvement of common bean nutritional quality has advantages in marketing and can contribute to society as a food source. The objective of this study was to evaluate the genetic variability for grain yield, calcium and iron concentrations in grains of inbred common bean lines obtained by different breeding methods. For this, 136 F7 inbred lines were obtained using the Pedigree method and 136 F7 inbred lines were obtained using the Single-Seed Descent (SSD method. The lines showed genetic variability for grain yield, and concentrations of calcium and iron independently of the method of advancing segregating populations. The Pedigree method allows obtaining a greater number of lines with high grain yield. Selection using the SSD method allows the identification of a larger number of lines with high concentrations of calcium and iron in grains. Weak negative correlations were found between grain yield and calcium concentration (r = -0.0994 and grain yield and iron concentration (r = -0.3926. Several lines show genetic superiority for grain yield and concentrations of calcium and iron in grains and their selection can result in new common bean cultivars with high nutritional quality.

  19. Iron loss in high-power arc steelmaking furnaces

    Directory of Open Access Journals (Sweden)

    V. P. Karasyov

    2016-07-01

    Full Text Available There is considered the power operating mode of a high-power arc steelmaking furnaces (ASMF in the period of the flat bath. It is revealed that electric energy is mainly spent for heating and overheating the foamed slag. Heat transferring from slag to metal is carried out by the convective agitation of the bath. For agitation there is used intensive purging of the bath with oxygen that causes increased iron losses with the running foamed slag. There are noted the negative points of working with the foamed slag. It is recommended to expand R&D in the field of optimizing the power operating mode of high-power ASMF.

  20. Neuroprotective effect of the active components of three Chinese herbs on brain iron load in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Dong, Xian-Hui; Gao, Wei-Juan; Kong, Wei-Na; Xie, Hong-Lin; Peng, Yan; Shao, Tie-Mei; Yu, Wen-Guo; Chai, Xi-Qing

    2015-04-01

    Alzheimer's disease (AD) is a neurodegenerative brain disorder and the most common cause of dementia. New treatments for AD are required due to its increasing prevalence in aging populations. The present study evaluated the effects of the active components of Epimedium, Astragalus and Radix Puerariae on learning and memory impairment, β-amyloid (Aβ) reduction and brain iron load in an APPswe/PS1ΔE9 transgenic mouse model of AD. Increasing evidence indicates that a disturbance of normal iron homeostasis may contribute to the pathology of AD. However, the underlying mechanisms resulting in abnormal iron load in the AD brain remain unclear. It has been hypothesized that the brain iron load is influenced by the deregulation of certain proteins associated with brain iron metabolism, including divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1). The present study investigated the effects of the active components of Epimedium, Astragalus and Radix Puerariae on the expression levels of DMT1 and FPN1. The treatment with the active components reduced cognitive deficits, inhibited Aβ plaque accumulation, reversed Aβ burden and reduced the brain iron load in AD model mice. A significant increase was observed in the levels of DMT1-iron-responsive element (IRE) and DMT1-nonIRE in the hippocampus of the AD mouse brain, which was reduced by treatment with the active components. In addition, the levels of FPN1 were significantly reduced in the hippocampus of the AD mouse brain compared with those of control mice, and these levels were increased following treatment with the active components. Thus, the present study indicated that the active components of Epimedium, Astragalus and Radix Puerariae may exert a neuroprotective effect against AD by reducing iron overload in the AD brain and may provide a novel approach for the development of drugs for the treatment of AD.

  1. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans.

    Science.gov (United States)

    Hawkings, Jon R; Wadham, Jemma L; Tranter, Martyn; Raiswell, Rob; Benning, Liane G; Statham, Peter J; Tedstone, Andrew; Nienow, Peter; Lee, Katherine; Telling, Jon

    2014-05-21

    The Greenland and Antarctic Ice Sheets cover ~ 10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40-2.54 Tg per year in Greenland and 0.06-0.17 Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting.

  2. Synthesis of highly magnetic iron nanoparticles suitable for field structuring using a β-diketone surfactant

    Science.gov (United States)

    Huber, Dale L.; Venturini, Eugene L.; Martin, James E.; Provencio, Paula P.; Patel, Rina J.

    2004-07-01

    We describe the synthesis of highly magnetic iron nanoparticles using a novel surfactant, a β-diketone. We have produced 6 nm iron nanoparticles with an unusually high saturation magnetization of more than 80% the value of bulk iron. Additionally, we measured a particle susceptibility of 14 (MKS units), which is far above the value possible for micron-scale spherical particles. These properties will allow for formation of composites that can be highly structured by magnetic fields.

  3. Synthesis of highly magnetic iron nanoparticles suitable for field structuring using a {beta}-diketone surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.L. E-mail: dlhuber@sandia.gov; Venturini, E.L.; Martin, J.E.; Provencio, P.P.; Patel, R.J

    2004-07-01

    We describe the synthesis of highly magnetic iron nanoparticles using a novel surfactant, a {beta}-diketone. We have produced 6 nm iron nanoparticles with an unusually high saturation magnetization of more than 80% the value of bulk iron. Additionally, we measured a particle susceptibility of 14 (MKS units), which is far above the value possible for micron-scale spherical particles. These properties will allow for formation of composites that can be highly structured by magnetic fields.

  4. High iron content and bioavailability in humans from four species of marine algae.

    Science.gov (United States)

    García-Casal, Maria N; Pereira, Ana C; Leets, Irene; Ramírez, José; Quiroga, Maria F

    2007-12-01

    Searching for economical, nonconventional sources of iron is important in underdeveloped countries to combat iron deficiency and anemia. Our objective was to study iron, vitamin C, and phytic acid composition and also iron bioavailability from 4 species of marine algae included in a rice-based meal. Marine algae (Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp) were analyzed for monthly variations in iron and for ascorbic acid and phytic acid concentrations. A total of 96 subjects received rice-based meals containing the 4 species of marine algae in different proportions, raw or cooked. All meals contained radioactive iron. Absorption was evaluated by calculating the radioactive iron incorporation in subjects' blood. Iron concentrations in algae were high and varied widely, depending on the species and time of year. The highest iron concentrations were found in Sargassum (157 mg/100 g) and Gracilariopsis (196 mg/100 g). Phytates were not detected in the algae and ascorbic acid concentration fluctuated between 38 microg/g dry weight (Ulva) and 362 microg/g dry weight (Sargassum). Algae significantly increased iron absorption in rice-based meals. Cooking did not affect iron absorption compared with raw algae. Results indicate that Ulva sp, Sargassum sp, Porphyra sp, and Gracilariopsis sp are good sources of ascorbic acid and bioavailable iron. The percentage of iron absorption was similar among all algae tested, although Sargassum sp resulted in the highest iron intake. Based on these results, and on the high reproduction rates of algae during certain seasons, promoting algae consumption in some countries could help to improve iron nutrition.

  5. Effect of Heat Treatment on Mechanical Property of High Cr-W Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Liu Jianping; Li Lixia

    2007-01-01

    The microstructure of high Cr-W cast iron after heat treatment were analyzed, and the effect of various heat treatment temperature and time on mechanical properties of high Cr-W cast iron were studied, and the best process parameter of heat treatment was provided in this paper. The results show that the heat treatment can improve the mechanical property of high Cr-W cast iron, and higher synthetic mechanical property of high Cr-W cast iron can be obtained when treated with normalization at 980℃ for 2h and tempered at 400℃ for 2h.

  6. Iron supplementation at high altitudes induces inflammation and oxidative injury to lung tissues in rats

    Energy Technology Data Exchange (ETDEWEB)

    Salama, Samir A., E-mail: salama.3@buckeyemail.osu.edu [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Cairo 11751 (Egypt); Department of Pharmacology and GTMR Unit, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); Omar, Hany A. [Department of Pharmacology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62514 (Egypt); Maghrabi, Ibrahim A. [Department of Clinical Pharmacy, College of Clinical Pharmacy, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); AlSaeed, Mohammed S. [Department of Surgery, College of Medicine, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia); EL-Tarras, Adel E. [High Altitude Research Center, Taif University, Al-Haweiah, Taif 21974 (Saudi Arabia)

    2014-01-01

    Exposure to high altitudes is associated with hypoxia and increased vulnerability to oxidative stress. Polycythemia (increased number of circulating erythrocytes) develops to compensate the high altitude associated hypoxia. Iron supplementation is, thus, recommended to meet the demand for the physiological polycythemia. Iron is a major player in redox reactions and may exacerbate the high altitudes-associated oxidative stress. The aim of this study was to explore the potential iron-induced oxidative lung tissue injury in rats at high altitudes (6000 ft above the sea level). Iron supplementation (2 mg elemental iron/kg, once daily for 15 days) induced histopathological changes to lung tissues that include severe congestion, dilatation of the blood vessels, emphysema in the air alveoli, and peribronchial inflammatory cell infiltration. The levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), lipid peroxidation product and protein carbonyl content in lung tissues were significantly elevated. Moreover, the levels of reduced glutathione and total antioxidant capacity were significantly reduced. Co-administration of trolox, a water soluble vitamin E analog (25 mg/kg, once daily for the last 7 days of iron supplementation), alleviated the lung histological impairments, significantly decreased the pro-inflammatory cytokines, and restored the oxidative stress markers. Together, our findings indicate that iron supplementation at high altitudes induces lung tissue injury in rats. This injury could be mediated through excessive production of reactive oxygen species and induction of inflammatory responses. The study highlights the tissue injury induced by iron supplementation at high altitudes and suggests the co-administration of antioxidants such as trolox as protective measures. - Highlights: • Iron supplementation at high altitudes induced lung histological changes in rats. • Iron induced oxidative stress in lung tissues of rats at high altitudes. • Iron

  7. Iron-nickel alloy from iron meteorite Chinga studied by Moessbauer spectroscopy with high velocity resolution

    Energy Technology Data Exchange (ETDEWEB)

    Oshtrakh, M. I., E-mail: oshtrakh@mail.utnet.ru; Grokhovsky, V. I.; Abramova, N. V. [Ural State Technical University-UPI, Faculty of Physical Techniques and Devices for Quality Control (Russian Federation); Semionkin, V. A. [Ural State Technical University-UPI, Faculty of Experimental Physics (Russian Federation); Milder, O. B. [Ural State Technical University-UPI, Radio-Technical Department (Russian Federation)

    2009-04-15

    Study of iron-nickel alloy from iron meteorite Chinga using Moessbauer spectroscopy with improved velocity resolution (measurement and presentation in 4,096 channels) revealed six magnetic components which may be related to various {alpha}-Fe(Ni, Co) and {gamma}-Fe(Ni, Co) phases while previous study with low velocity resolution (in 512 channels) revealed only three magnetic components. This new result was in agreement with the scanning electron microscopy study.

  8. The effect of high-frequencies loading on the fatigue cracking of nodular cast iron

    Directory of Open Access Journals (Sweden)

    R. Ulewicz

    2017-01-01

    Full Text Available The article presents the results of fatigue tests using high-frequency loading of nodular cast iron. Nodular cast iron GJS-500-7, GJS-600-3 and cast iron ADI with a tensile strength of Rm = 1 125 MPa were used for the tests. The fatigue tests were conducted on a resonance testing machine. For the cast iron grades under investigation, fatigue characteristics in high and ultra-high-cycle regions were experimentally determined. After the completion of the tests, the fractographic analysis of fatigue fractures was made with the aim of determining the fatigue crack initiation location and the fracture mechanism.

  9. Brain Iron Dysregulation and Central Nervous System Diseases%铁代谢异常与中枢神经系统疾病

    Institute of Scientific and Technical Information of China (English)

    林冬; 丁晶; 汪昕

    2011-01-01

    The presence of the blood-brain barrier explains the relative independence of the brain iron metabolism from circulatory iron homeostasis. Disturbances of brain iron metabolism can result in iron accumulation or deficiency in brain , which can impair cellular biological function and promote cell to die. Recent advances on brain iron metabolism have revealed the possible role of brain iron dysregulation in the development or pathogenesis of some central nervous system diseases, such as Alzheimer ' s disease, Parkinson ' s disease, epilepsy, and restless leg syndrome.%由于血脑屏障的存在,脑铁代谢与外周器官不同.铁在脑内代谢的异常可致脑铁沉积或脑内铁缺乏,导致细胞生理功能障碍,引起神经细胞的死亡.目前已经发现阿尔茨海默病、帕金森病、癫、不宁腿综合征的发病机制及疾病的发展与脑铁代谢异常有关.

  10. Helicobacter pylori Infection Induces Anemia, Depletes Serum Iron Storage, and Alters Local Iron-Related and Adult Brain Gene Expression in Male INS-GAS Mice

    OpenAIRE

    2015-01-01

    Iron deficiency anemia (IDA) affects > 500 million people worldwide, and is linked to impaired cognitive development and function in children. Helicobacter pylori, a class 1 carcinogen, infects about half of the world's population, thus creating a high likelihood of overlapping risk. This study determined the effect of H. pylori infection on iron homeostasis in INS-GAS mice. Two replicates of INS-GAS/FVB male mice (n = 9-12/group) were dosed with H. pylori (Hp) strain SS1 or sham dosed at 6-9...

  11. Iron-oxo clusters biomineralizing on protein surfaces: Structural analysis of Halobacterium salinarum DpsA in its low- and high-iron states

    OpenAIRE

    Zeth, Kornelius; Offermann, Stefanie; Essen, Lars-Oliver; Oesterhelt, Dieter

    2004-01-01

    The crystal structure of the Dps-like (Dps, DNA-protecting protein during starvation) ferritin protein DpsA from the halophile Halobacterium salinarum was determined with low endogenous iron content at 1.6-Å resolution. The mechanism of iron uptake and storage was analyzed in this noncanonical ferritin by three high-resolution structures at successively increasing iron contents. In the high-iron state of the DpsA protein, up to 110 iron atoms were localized in the dodecameric protein complex....

  12. High temperature oxidation of iron-chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, Lars

    2003-06-15

    The high temperature oxidation of the ferritic alloy Fe78Cr22 has been investigated in the present work. The effect of small alloying additions of cerium and/or silicon was also investigated. The alloys were oxidized at 973, 1173 and 1373 K in either air or a hydrogen/argon mixture. The various reaction atmospheres contained between 0.02 and 50% water vapour. The oxide scales formed on the various alloys at 973 K consisted of thin chromia layers. The oxide scales grown on the alloys at 1173 K also consisted of a chromia layer. The microstructure of the chromia scales was found to depend on the reaction atmosphere. The chromia scales grown in hydrogen/argon atmospheres formed oxide whiskers and oxide ridges at the surface of the scales, while the chromia scales grown in air formed larger oxide grains near the surface. This difference in oxide microstructure was due to the vaporization of chromium species from the chromia scales grown in air. Two different growth mechanisms are proposed for the growth of oxide whiskers. The growth rate of the chromia scales was independent of the oxygen activity. This is explained by a growth mechanism of the chromia scales, where the growth is governed by the diffusion of interstitial chromium. The addition of silicon to the iron-chromium alloy resulted in the formation of silica particles beneath the chromia scale. The presence of silicon in the alloy was found to decrease the growth rate of the chromia scale. This is explained by a blocking mechanism, where the silica particles beneath the chromia scale partly block the outwards diffusion of chromium from the alloy to the chromia scale. The addition of cerium to the iron-chromium alloy improved the adhesion of the chromia scale to the alloy and decreased the growth rate of chromia. It was observed that the minimum concentration of cerium in the alloy should be 0.3 at.% in order to observe an effect of the cerium addition. The effect of cerium is explained by the &apos

  13. High temperature oxidation of iron-chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mikkelsen, Lars

    2003-06-15

    The high temperature oxidation of the ferritic alloy Fe78Cr22 has been investigated in the present work. The effect of small alloying additions of cerium and/or silicon was also investigated. The alloys were oxidized at 973, 1173 and 1373 K in either air or a hydrogen/argon mixture. The various reaction atmospheres contained between 0.02 and 50% water vapour. The oxide scales formed on the various alloys at 973 K consisted of thin chromia layers. The oxide scales grown on the alloys at 1173 K also consisted of a chromia layer. The microstructure of the chromia scales was found to depend on the reaction atmosphere. The chromia scales grown in hydrogen/argon atmospheres formed oxide whiskers and oxide ridges at the surface of the scales, while the chromia scales grown in air formed larger oxide grains near the surface. This difference in oxide microstructure was due to the vaporization of chromium species from the chromia scales grown in air. Two different growth mechanisms are proposed for the growth of oxide whiskers. The growth rate of the chromia scales was independent of the oxygen activity. This is explained by a growth mechanism of the chromia scales, where the growth is governed by the diffusion of interstitial chromium. The addition of silicon to the iron-chromium alloy resulted in the formation of silica particles beneath the chromia scale. The presence of silicon in the alloy was found to decrease the growth rate of the chromia scale. This is explained by a blocking mechanism, where the silica particles beneath the chromia scale partly block the outwards diffusion of chromium from the alloy to the chromia scale. The addition of cerium to the iron-chromium alloy improved the adhesion of the chromia scale to the alloy and decreased the growth rate of chromia. It was observed that the minimum concentration of cerium in the alloy should be 0.3 at.% in order to observe an effect of the cerium addition. The effect of cerium is explained by the &apos

  14. Superparamagnetic iron oxide nanoparticles coated with different polymers and their MRI contrast effects in the mouse brains

    Science.gov (United States)

    Xie, Songbo; Zhang, Baolin; Wang, Lei; Wang, Jun; Li, Xuan; Yang, Gao; Gao, Fabao

    2015-01-01

    PEG and PEG/PEI modified superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by the thermal decomposition of iron (III) acetylacetonate (Fe(acac)3) in poly (ethylene glycol) (PEG) containing poly (ethylene imine) (PEI) (0 or 0.3 g). PEG/PEI-SPIONs were coated with Tween 80 (PEG/PEI/Tween 80-SPIONs). Fourier transform infrared spectroscopy (FTIR) analyses indicated that PEG, PEG/PEI and PEG/PEI/Tween 80 were attached to the surfaces of the SPIONs. The PEG-SPIONs, PEG/PEI-SPIONs and PEG/PEI/Tween 80-SPIONs performed excellent colloidal stability in the phosphate buffered saline (PBS), and in deionized water with the mean hydrodynamic sizes of 19.5, 21.0, 24.0 nm and the zeta potentials of -5.0, 35.0, 19.0 mV, respectively. All the SPIONs showed low cytotoxicity assessed by the MTT assay. In vivo magnetic resonance imaging (MRI) of the Kunming (KM) mouse brains were performed, the PEG-SPIONs, PEG/PEI-SPIONs and PEG/PEI/Tween 80-SPIONs exhibited vascular imaging effects in bulbus olfactorius, frontal cortex, temporal, thalamus and brain stem of the mouse brains after 24 h intravenous injection of the nanoparticles. The SPIONs have potentials as MRI contrast agents in the mouse brains.

  15. A Rare Earth High-iron Aluminum Alloy Cable Company to Settle in Chongqing

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On September 14,the reporter learnt from the Seminar on Application of New Rare Earth High-iron Aluminum Alloy Cable Technologies for Energy Conservation and Environmental Protection held by Chongqing Electric Industry Association that a rare earth high-iron aluminum alloy cable company with

  16. Determination of Trace Iron in High Purity Sodium Fluoride by Graphite Furnace Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A method is described for the direct determination of iron in high purity sodium fluoride using graphite furnace atomic absorption spectrometry. Interferences caused by the matrix are investigated. It is shown that the ashing temperature can be increased to 1 400°C and matrix interferences eliminated, the sensi tivity of iron increased in 1.27 fold by the addition of nickel nitrate. The method is applied to the determina tion of iron in sodium fluoride and satisfactory results are obtained.

  17. The Mycobacterium tuberculosis high-affinity iron importer, IrtA, contains an FAD-binding domain.

    Science.gov (United States)

    Ryndak, Michelle B; Wang, Shuishu; Smith, Issar; Rodriguez, G Marcela

    2010-02-01

    Iron is an essential nutrient not freely available to microorganisms infecting mammals. To overcome iron deficiency, bacteria have evolved various strategies including the synthesis and secretion of high-affinity iron chelators known as siderophores. The siderophores produced and secreted by Mycobacterium tuberculosis, exomycobactins, compete for iron with host iron-binding proteins and, together with the iron-regulated ABC transporter IrtAB, are required for the survival of M. tuberculosis in iron deficient conditions and for normal replication in macrophages and in mice. This study further characterizes the role of IrtAB in M. tuberculosis iron acquisition. Our results demonstrate a role for IrtAB in iron import and show that the amino terminus domain of IrtA is a flavin-adenine dinucleotide-binding domain essential for iron acquisition. These results suggest a model in which the amino terminus of IrtA functions to couple iron transport and assimilation.

  18. Highly mobile carriers in iron-based superconductors

    Science.gov (United States)

    Ovchenkov, Y. A.; Chareev, D. A.; Kulbachinskii, V. A.; Kytin, V. G.; Presnov, D. E.; Volkova, O. S.; Vasiliev, A. N.

    2017-03-01

    The field and temperature dependencies of the resistivity and Hall effect are measured for FeSe{}1-xS{}x (x = 0.04, 0.09, and 0.19) single crystals. Sample FeSe{}0.81S{}0.19 does not show a transition to an orthorhombic phase and at low temperatures exhibits transport properties, which are very different from those of orthorhombic samples. The behavior of FeSe{}0.81S{}0.19 is well described by the simple two-band model with comparable values of the hole and electron mobilities. The characteristics of the low-temperature transport properties of the orthorhombic Fe(SeS) samples are largely determined by the presence of a small number of highly mobile carriers, which may originate from the local regions of the Fermi surface, presumably, nearby the Van Hove singularity points. Our results, for the first time, demonstrate a strong evolution of a tiny band of highly mobile electrons at a tetragonal to orthorhombic quantum phase transition. The behavior of this band can be the reason for the diverging nematic susceptibility, determined from elastoresistivity, which is considered one of the most intriguing phenomena in the physics of iron-based superconductors.

  19. Melter Throughput Enhancements for High-Iron HLW

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A. A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Gan, Hoa [The Catholic University of America, Washington, DC (United States); Joseph, Innocent [The Catholic University of America, Washington, DC (United States); Pegg, Ian L. [The Catholic University of America, Washington, DC (United States); Matlack, Keith S. [The Catholic University of America, Washington, DC (United States); Chaudhuri, Malabika [The Catholic University of America, Washington, DC (United States); Kot, Wing [The Catholic University of America, Washington, DC (United States)

    2012-12-26

    This report describes work performed to develop and test new glass and feed formulations in order to increase glass melting rates in high waste loading glass formulations for HLW with high concentrations of iron. Testing was designed to identify glass and melter feed formulations that optimize waste loading and waste processing rate while meeting all processing and product quality requirements. The work included preparation and characterization of crucible melts to assess melt rate using a vertical gradient furnace system and to develop new formulations with enhanced melt rate. Testing evaluated the effects of waste loading on glass properties and the maximum waste loading that can be achieved. The results from crucible-scale testing supported subsequent DuraMelter 100 (DM100) tests designed to examine the effects of enhanced glass and feed formulations on waste processing rate and product quality. The DM100 was selected as the platform for these tests due to its extensive previous use in processing rate determination for various HLW streams and glass compositions.

  20. Inflammation-induced brain endothelial activation leads to uptake of electrostatically stabilized iron oxide nanoparticles via sulfated glycosaminoglycans.

    Science.gov (United States)

    Berndt, Dominique; Millward, Jason M; Schnorr, Jörg; Taupitz, Matthias; Stangl, Verena; Paul, Friedemann; Wagner, Susanne; Wuerfel, Jens T; Sack, Ingolf; Ludwig, Antje; Infante-Duarte, Carmen

    2017-05-01

    Based on our previous data on the presence of very small superparamagnetic iron oxide nanoparticles (VSOP) on brain endothelial structures during experimental autoimmune encephalomyelitis (EAE), we investigated the mechanisms of VSOP binding on inflamed brain endothelial cells in vivo and in vitro. After intravenous application, VSOP were detected in brain endothelial cells of EAE animals at peak disease and prior to clinical onset. In vitro, inflammatory stimuli increased VSOP uptake by brain endothelial bEnd.3 cells, which we confirmed in primary endothelial cells and in bEnd.3 cells cultured under shear stress. Transmission electron microscopy and blocking experiments revealed that during inflammation VSOP were endocytosed by bEnd.3. Modified sulfated glycosaminoglycans (GAG) on inflamed brain endothelial cells were the primary binding site for VSOP, as GAG degradation and inhibition of GAG sulfation reduced VSOP uptake. Thus, VSOP-based MRI is sensitive to visualize early neuroinflammatory processes such as GAG modifications on brain endothelial cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. BrainMaps.org - Interactive High-Resolution Digital Brain Atlases and Virtual Microscopy.

    Science.gov (United States)

    Mikula, Shawn; Stone, James M; Jones, Edward G

    2008-01-01

    BrainMaps.org is an interactive high-resolution digital brain atlas and virtual microscope that is based on over 20 million megapixels of scanned images of serial sections of both primate and non-primate brains and that is integrated with a high-speed database for querying and retrieving data about brain structure and function over the internet. Complete brain datasets for various species, including Homo sapiens, Macaca mulatta, Chlorocebus aethiops, Felis catus, Mus musculus, Rattus norvegicus, and Tyto alba, are accessible online. The methods and tools we describe are useful for both research and teaching, and can be replicated by labs seeking to increase accessibility and sharing of neuroanatomical data. These tools offer the possibility of visualizing and exploring completely digitized sections of brains at a sub-neuronal level, and can facilitate large-scale connectional tracing, histochemical and stereological analyses.

  2. Determination of iron in highly-saline matrices by FIA-ICP-MS

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    Analysis of iron by inductively-coupled-plasma mass-spectrometry (ICP-MS) may be significantly improved by applying a protocol of flow-injection analysis. The iron species of the sample was preconcentrated by an ammonia buffer at pH = 9.2 on a filterless nylon-knotted reactor, and the adsorbed...... species were subsequently eluted by hydrochloric acid and analysed by ICP-MS. During the FIA step of preconcentration, a high degree of salinity did not influence the adsorption mechanism of iron, which may be related to formation of iron-hydroxide complexes at the sites of amide moieties of the nylon...

  3. Superparamagnetic Iron Oxide Nanoparticles Modified with Tween 80 Pass through the Intact Blood-Brain Barrier in Rats under Magnetic Field.

    Science.gov (United States)

    Huang, Yinping; Zhang, Baolin; Xie, Songbo; Yang, Boning; Xu, Qin; Tan, Jie

    2016-05-11

    The methods for the delivery of theranostic agents across the blood-brain barrier (BBB) are highly required. Superparamagnetic iron oxide nanoparticles (SPIONs) coated with PEG (poly(ethylene glycol)), PEI (poly(ethylene imine)), and Tween 80 (polysorbate 80) (Tween-SPIONs) were prepared. We demonstrate the effective passage of tail-vein-injected Tween-SPIONs across normal BBB in rats under an external magnetic field (EMF). The quantitative analyses show significant accumulation of SPIONs in the cortex near the magnet, with progressively lower accumulation in brain tissues far from the magnet. A transmission electron microscopy picture of an ultrathin section of the rat brain displays Tween-SPIONs crossing the BBB. The comparative study confirms that both the Tween-80 modification and EMF play crucial roles in the effective passage of SPIONs across the intact BBB. However, the magnetic force alone cannot drag the SPIONs coated with PEI/PEG polymers through the BBB. The results indicate the Tween-SPIONs cross the BBB via an active penetration facilitated by EMF. This work is encouraging for further study on the delivery of drug or diagnostic agents into the parenchyma of the brain for dealing with neurological disorders by using Tween-SPIONs carriers under EMF.

  4. 医学综述杂志社铁离子对大脑毒性的研究进展%Research Progress of Toxicity of Iron Ion to Brain

    Institute of Scientific and Technical Information of China (English)

    徐金

    2012-01-01

    铁离子广泛存在于脑组织各部位,基底神经节含量最高,红核、黑质和齿状核较多,大脑皮质和小脑相对较少.铁毒性作用主要基于芬顿化学作用,铁与活性氧中间物反应,可产生高反应的自由基.脑内不同的细胞对铁超载及血红蛋白的防御反应,都可引起对神经元的毒性作用.自由铁通过产生的自由基对脑有高度的毒性作用,然而,在脑损伤和脑出血中铁的浓度是否是导致神经元损伤和死亡的必然因素,血液是否是促使神经元死亡的原因尚不是很清楚.%Iron ion exists extensively in each part of brain tissue, mostly in basal ganglia, more in red nucleus , substantia nigra and dentate nucleus, less in cerebral cortex and cerebellum. Toxic effect of iron is mainly based on Fenton chemical actions,the actions of iron and reactive oxygen intermediates,generate highly-active free radicals. Various cells in brain have the defensive reaction against iron overloading and hemoglobin, which can all induce the toxicity effect in neuron. Free iron produced free radical has high toxicity to brain. Whether the density of iron is a necessary factor to induce neuron injuries and death and if cerebral hemorrhage can promote the neuron death is still not clear.

  5. Synchronous Upgrading Iron and Phosphorus Removal from High Phosphorus Oolitic Hematite Ore by High Temperature Flash Reduction

    Directory of Open Access Journals (Sweden)

    Deqing Zhu

    2016-05-01

    Full Text Available In this paper, an effective method was developed to remove phosphorus and upgrade iron from high phosphorus oolitic hematite ore by high temperature flash reduction—a wet magnetic separation process. A thermodynamic analysis of iron and phosphorus mineral reactions and experiments with Fe-P separation process were performed, and the mechanism of phosphorus removal and beneficiation of iron is discussed as well. The results show that under the proper conditions, a final metallic iron powder assaying over 91% Fe and 0.25% P was obtained with iron recovery of 90% and phosphorus removal rate of 91.79% using the new process, indicating that the high temperature flash reduction process is a feasible and efficient way to process this kind of complex and refractory iron ore. Moreover, sodium sulfate is found to be capable of improving the removal of phosphorus and the upgrading of iron, as well as enhancing the growth of metallic iron grains significantly for higher recovery of iron.

  6. Tracking inhomogeneity in high-capacity lithium iron phosphate batteries

    Science.gov (United States)

    Paxton, William A.; Zhong, Zhong; Tsakalakos, Thomas

    2015-02-01

    Energy-dispersive x-ray diffraction (EDXRD) is one of the few techniques that can internally probe a sealed battery under operating conditions. In this paper, we use EDXRD with ultrahigh energy synchrotron radiation to track inhomogeneity in a cycled high-capacity lithium iron phosphate cell under in-situ and operando conditions. A sequence of depth-profile x-ray diffraction spectra are collected with 40 μm resolution as the cell is discharged. Additionally, nine different locations of the cell are tracked independently throughout a second discharge process. In each case, a two-peak reference intensity ratio analysis (RIR) was used on the LiFePO4 311 and the FePO4 020 reflections to estimate the relative phase abundance of the lithiated and non-lithiated phases. The data provide a first-time look at the dynamics of electrochemical inhomogeneity in a real-world battery. We observe a strong correlation between inhomogeneity and overpotential in the galvanic response of the cell. Additionally, the data closely follow the behavior that is predicted by the resistive-reactant model originally proposed by Thomas-Alyea. Despite a non-linear response in the independently measured locations, the behavior of the ensemble is strikingly linear. This suggests that effects of inhomogeneity can be elusive and highlights the power of the EDXRD technique.

  7. Improvement of a High Velocity Compaction Technique for Iron Powder

    Institute of Scientific and Technical Information of China (English)

    Dil Faraz KHAN; Haiqing YIN; Zahid USMAN; Matiullah KHAN; Xianjie YUAN; Wenhao WANG; Xuanhui QU

    2013-01-01

    Water atomized pure iron powder was compacted by high velocity compaction (HVC) with and without upper relaxation assist (URA) device.The influence of URA device on green density,spring back,green strength and hardness was studied.Morphological characteristics of the samples were observed by scanning electron microscope (SEM).Green strength of the samples was measured by computer controlled universal testing machine.The results show that as stroke length increases,the green density,green strength and hardness of the compacts increase gradually.At the identical stroke length,the green density of the compacts pressed with URA devise was 2% higher than the compacts pressed without URA device.The green strength and hardness of the compacts pressed with URA device were higher than the compacts pressed without URA device.Furthermore,the radial spring back of the compacts decreased gradually with the increment in stroke length,whilst that of compacts prepared with URA device was lower.

  8. Copper Deficiency in Sheep with High Liver Iron Accumulation

    Directory of Open Access Journals (Sweden)

    Isadora Karolina Freitas de Sousa

    2012-01-01

    Full Text Available An outbreak of enzootic ataxia among sheep raised in the northeastern region of Brazil is described. Copper (Cu deficiency was diagnosed in a herd of 56 sheep, among which five presented characteristic clinical symptoms of enzootic ataxia. The symptoms began 30 days after birth, with a clinical condition that included locomotion difficulty, limb ataxia, tremors, and continual falls. Liver biopsies were performed and blood was collected to determine hepatic and plasmatic Cu, iron (Fe, and zinc (Zn concentration, respectively. The laboratory results showed that the animals presented low copper concentrations in the plasma and liver, without difference between the clinically healthy animals and those affected by enzootic ataxia. Even after supplementation with adequate Cu levels had been recommended, it was found on a new visit to the farm four months later that one animal still presented a clinical condition and that the hepatic Cu levels of the herd had not risen. Despite the low copper content of the diet, the high hepatic Fe levels found suggest that antagonism due to this element may have been an important factor in triggering copper deficiency in these animals, and thus, additional copper supplementation may be necessary for these animals.

  9. Mössbauer study of exogenous iron redistribution between the brain and the liver after administration of {sup 57}Fe{sub 3}O{sub 4} ferrofluid in the ventricle of the rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Polikarpov, Dmitry, E-mail: polikarpov.imp@gmail.com [National Research Center “Kurchatov Institute”, Moscow (Russian Federation); Russian National Research Medical University named after N.I.Pirogov, Moscow (Russian Federation); Gabbasov, Raul; Cherepanov, Valery [National Research Center “Kurchatov Institute”, Moscow (Russian Federation); Loginova, Natalia; Loseva, Elena [Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow (Russian Federation); Nikitin, Maxim [Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Yurenia, Anton; Panchenko, Vladislav [National Research Center “Kurchatov Institute”, Moscow (Russian Federation); Lomonosov Moscow State University, Moscow (Russian Federation)

    2015-04-15

    Iron clearance pathways after the injection of {sup 57}Fe{sub 3}O{sub 4}-based ferrofluid into the brain ventricles were studied histologically and by Mössbauer spectroscopy. It was found that the dextran coated initial nanobeads of the ferrofluid disintegrated in the brain into separate superparamagnetic nanoparticles within a week after the injection. The exogenous iron completely exited all ventricular cavities of the brain within a week after the injection but remained in the white matter for months. Kupffer cells with the exogenous iron appeared in the rat liver 2 hours after the injection. Their concentration reached its maximum on the third day and dropped to zero within a week. The exogenous iron appeared in the spleen a week after the injection and remained in the spleen for months.

  10. Determination of iron in highly-saline matrices by FIA-ICP-MS

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    species were subsequently eluted by hydrochloric acid and analysed by ICP-MS. During the FIA step of preconcentration, a high degree of salinity did not influence the adsorption mechanism of iron, which may be related to formation of iron-hydroxide complexes at the sites of amide moieties of the nylon...

  11. Exome sequence reveals mutations in CoA synthase as a cause of neurodegeneration with brain iron accumulation.

    Science.gov (United States)

    Dusi, Sabrina; Valletta, Lorella; Haack, Tobias B; Tsuchiya, Yugo; Venco, Paola; Pasqualato, Sebastiano; Goffrini, Paola; Tigano, Marco; Demchenko, Nikita; Wieland, Thomas; Schwarzmayr, Thomas; Strom, Tim M; Invernizzi, Federica; Garavaglia, Barbara; Gregory, Allison; Sanford, Lynn; Hamada, Jeffrey; Bettencourt, Conceição; Houlden, Henry; Chiapparini, Luisa; Zorzi, Giovanna; Kurian, Manju A; Nardocci, Nardo; Prokisch, Holger; Hayflick, Susan; Gout, Ivan; Tiranti, Valeria

    2014-01-02

    Neurodegeneration with brain iron accumulation (NBIA) comprises a clinically and genetically heterogeneous group of disorders with progressive extrapyramidal signs and neurological deterioration, characterized by iron accumulation in the basal ganglia. Exome sequencing revealed the presence of recessive missense mutations in COASY, encoding coenzyme A (CoA) synthase in one NBIA-affected subject. A second unrelated individual carrying mutations in COASY was identified by Sanger sequence analysis. CoA synthase is a bifunctional enzyme catalyzing the final steps of CoA biosynthesis by coupling phosphopantetheine with ATP to form dephospho-CoA and its subsequent phosphorylation to generate CoA. We demonstrate alterations in RNA and protein expression levels of CoA synthase, as well as CoA amount, in fibroblasts derived from the two clinical cases and in yeast. This is the second inborn error of coenzyme A biosynthesis to be implicated in NBIA.

  12. The presence of serum alters the properties of iron oxide nanoparticles and lowers their accumulation by cultured brain astrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Geppert, Mark; Petters, Charlotte [University of Bremen, Centre for Biomolecular Interactions Bremen (Germany); Thiel, Karsten [Fraunhofer Institute for Manufacturing Technology and Advanced Materials (Germany); Dringen, Ralf, E-mail: ralf.dringen@uni-bremen.de [University of Bremen, Centre for Biomolecular Interactions Bremen (Germany)

    2013-01-15

    Iron oxide nanoparticles (IONPs) are considered for various diagnostic and therapeutic applications. Such particles are able to cross the blood-brain barrier and are taken up into brain cells. To test whether serum components affect the properties of IONPs and/or their uptake into brain cells, we have incubated dimercaptosuccinate-coated magnetic IONPs without and with fetal calf serum (FCS) and have exposed cultured brain astrocytes with IONPs in the absence or presence of FCS. Incubation with FCS caused a concentration-dependent increase in the average hydrodynamic diameter of the particles and of their zeta-potential. In the presence of 10 % FCS, the diameter of the IONPs increased from 57 {+-} 2 to 107 {+-} 6 nm and the zeta-potential of the particles from -22 {+-} 5 to -9 {+-} 1 mV. FCS affected also strongly the uptake of IONPs by cultured astrocytes. The efficient time- and temperature-dependent cellular accumulation of IONPs was lowered with increasing concentration of FCS by up to 90 %. In addition, in the absence of serum, endocytosis inhibitors did not alter the IONP accumulation by astrocytes, while chlorpromazine or wortmannin lowered significantly the accumulation of IONPs in the presence of FCS, suggesting that clathrin-mediated endocytosis and macropinocytosis are involved in astrocytic IONP uptake from serum-containing medium. These data demonstrate that the presence of FCS strongly affects the properties of IONPs as well as their accumulation by cultured brain cells.

  13. Iron and Mechanisms of Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Gabriela A. Salvador

    2011-01-01

    Full Text Available The accumulation of transition metals (e.g., copper, zinc, and iron and the dysregulation of their metabolism are a hallmark in the pathogenesis of several neurodegenerative diseases. This paper will be focused on the mechanism of neurotoxicity mediated by iron. This metal progressively accumulates in the brain both during normal aging and neurodegenerative processes. High iron concentrations in the brain have been consistently observed in Alzheimer's (AD and Parkinson's (PD diseases. In this connection, metalloneurobiology has become extremely important in establishing the role of iron in the onset and progression of neurodegenerative diseases. Neurons have developed several protective mechanisms against oxidative stress, among them, the activation of cellular signaling pathways. The final response will depend on the identity, intensity, and persistence of the oxidative insult. The characterization of the mechanisms mediating the effects of iron-induced increase in neuronal dysfunction and death is central to understanding the pathology of a number of neurodegenerative disorders.

  14. Early Iron Deficiency Has Brain and Behavior Effects Consistent with Dopaminergic Dysfunction123

    Science.gov (United States)

    Lozoff, Betsy

    2011-01-01

    To honor the late John Beard’s many contributions regarding iron and dopamine biology, this review focuses on recent human studies that test specific hypotheses about effects of early iron deficiency on dopamine system functioning. Short- and long-term alterations associated with iron deficiency in infancy can be related to major dopamine pathways (mesocortical, mesolimbic, nigrostriatal, tuberohypophyseal). Children and young adults who had iron deficiency anemia in infancy show poorer inhibitory control and executive functioning as assessed by neurocognitive tasks where pharmacologic and neuroimaging studies implicate frontal-striatal circuits and the mesocortical dopamine pathway. Alterations in the mesolimbic pathway, where dopamine plays a major role in behavioral activation and inhibition, positive affect, and inherent reward, may help explain altered social-emotional behavior in iron-deficient infants, specifically wariness and hesitance, lack of positive affect, diminished social engagement, etc. Poorer motor sequencing and bimanual coordination and lower spontaneous eye blink rate in iron-deficient anemic infants are consistent with impaired function in the nigrostriatal pathway. Short- and long-term changes in serum prolactin point to dopamine dysfunction in the tuberohypophyseal pathway. These hypothesis-driven findings support the adverse effects of early iron deficiency on dopamine biology. Iron deficiency also has other effects, specifically on other neurotransmitters, myelination, dendritogenesis, neurometabolism in hippocampus and striatum, gene and protein profiles, and associated behaviors. The persistence of poorer cognitive, motor, affective, and sensory system functioning highlights the need to prevent iron deficiency in infancy and to find interventions that lessen the long-term effects of this widespread nutrient disorder. PMID:21346104

  15. Microvascular brain pathology on high resolution MRI

    NARCIS (Netherlands)

    Veluw, S.J. van

    2015-01-01

    Cerebral small vessel disease (SVD) is a common finding in the aging human brain and is associated with stroke, cognitive decline, and dementia. On autopsy, SVD encompasses pathological processes affecting small arteries and arterioles. Magnetic resonance imaging (MRI) detects the consequences of th

  16. The hydraulic potential of high iron bearing steel slags

    Science.gov (United States)

    Ionescu, Denisa Virginia

    The incorporation of additives to the clinker or to the raw materials stream is a common practice in cement manufacture. However, steel slag, unlike its ironmaking parent the blast furnace slag, it is not a conventional admixture for cement. Currently most steel slags are slow cooled rendering stable crystalline compounds with minor hydraulic value. Nevertheless, if steel slags would be quenched and granulated, the resulting glassy product might display increased hydration and strength development potential. The use of steel slag in cement could contribute to important savings for both cement and steelmaking industries and provide a solution for the environmental problems linked to CO2 emissions and costs of transport and disposal. The purpose of this research is to explore the thermodynamics and kinetics of steel slag hydration in an effort to produce a cement additive, or a more promising material of near Portland cement composition. An important criteria used in the assessment of slags as potential cements is the presence of a glassy phase. At present, it is not very clear why glass enhances the hydration process. However, it is known that the free energy of formation for glasses is less than for crystals so that glasses are easier to hydrate compared to crystalline materials. In the particular case of steel slag, the glassy phase would have to contain high amounts of iron. Steel slags are known to display iron levels approximately 10 times higher than Portland cement and commonly used blast furnace slags. However, the effect of high Fe2O3 levels on the setting and strengthening of cement paste is not clearly understood due to the fact that most cement additives do not present this characteristic. The present work looks at the progress made in recycling steel slag as cement additive, the complexity of the hydration process in slags, the possibilities of improving the hydration potential of slags at laboratory and industrial level, and the problems that still

  17. Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation

    Institute of Scientific and Technical Information of China (English)

    LUO Li-qun; ZHANG Jing-sheng; YU Yong-fu

    2005-01-01

    Successful recovery of limonite from iron fines was achieved by using flocculation-high intensity magnetic separation (FIMS) and adding hydrolyzed and causticized flocculants according to the characteristic of iron fines. The separation results of the three iron samples are as follows: iron grade 66.77%-67.98% and the recovery of iron 69.26%-70.70% by the FIMS process with flocculants. The comparative results show that under the same separation conditions the FIMS process can effectively increase the recovery of iron by 10.97%-15.73%. The flowsheet results confirm the reliability of the process in a SHP high intensity magnetic separator. The concentrate product can be used as raw materials for direct reduction iron-smelting. The hydrolyzed and causticized flocculants can selectively flocculate fine feebly-magnetic iron mineral particles to increase their apparent separation sizes. The larger the separation size, the stronger the magnetic force. By comparing the separation results of the three samples it is found that among the three samples the higher the limonite content, the better the separation result. This means that the separation result relates closely to the flocculation process and the adding pattern of the flocculant.

  18. Regional distributions of manganese, iron, copper, and zinc in the brains of 6-hydroxydopamine-induced parkinsonian rats.

    Science.gov (United States)

    Tarohda, Tohru; Ishida, Yasushi; Kawai, Keiichi; Yamamoto, Masayoshi; Amano, Ryohei

    2005-09-01

    Time courses of changes in manganese, iron, copper, and zinc concentrations were examined in regions of the brain of a 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations were simultaneously determined in brain section at the level of the substantia nigra 1, 3, 7, 10, 14, and 21 days after the 6-OHDA treatment and compared with those of control rats. The distributions of these elements were obtained for 18 regions of the sagittal section (1-mm thick). The ICP-MS results indicated that Mn, Fe, Cu, and Zn levels of the 6-OHDA-induced parkinsonian brain were observed to increase in all regions that lay along the dopaminergic pathway. In the substantia nigra, the increase in Mn level occurred rapidly from 3 to 7 days and preceded those in the other elements, reaching a plateau in the 6-OHDA brain. Iron and Zn levels increased gradually until 7 days and then increased rapidly from 7 to 10 days. The increase in the copper level was slightly delayed. In other regions, such as the globus pallidus, putamen, and amygdala, the levels of Mn, Fe, Cu, and Zn increased with time after 6-OHDA treatment, although the time courses of their changes were region-specific. These findings contribute to our understanding of the roles of Mn and Fe in the induction of neurological symptoms and progressive loss of dopaminergic neurons in the development of Parkinson's disease. Manganese may hold the key to disturbing cellular Fe homeostasis and accelerating Fe levels, which play the most important role in the development of Parkinson's disease.

  19. High-valent iron in chemical and biological oxidations.

    Science.gov (United States)

    Groves, John T

    2006-04-01

    Various aspects of the reactivity of iron(IV) in chemical and biological systems are reviewed. Accumulated evidence shows that the ferryl species [Fe(IV)O](2+) can be formed under a variety of conditions including those related to the ferrous ion-hydrogen peroxide system known as Fenton's reagent. Early evidence that such a species could hydroxylate typical aliphatic C-H bonds included regioselectivities and stereospecificities for cyclohexanol hydroxylation that could not be accounted for by a freely diffusing hydroxyl radical. Iron(IV) porphyrin complexes are also found in the catalytic cycles of cytochrome P450 and chloroperoxidase. Model oxo-iron(IV) porphyrin complexes have shown reactivity similar to the proposed enzymatic intermediates. Mechanistic studies using mechanistically diagnostic substrates have implicated a radical rebound scenario for aliphatic hydroxylation by cytochrome P450. Likewise, several non-heme diiron hydroxylases, AlkB (Omega-hydroxylase), sMMO (soluble methane monooxygenase), XylM (xylene monooxygenase) and T4moH (toluene monooxygenase) all show clear indications of radical rearranged products indicating that the oxygen rebound pathway is a ubiquitous mechanism for hydrocarbon oxygenation by both heme and non-heme iron enzymes.

  20. Use of electron microscopy on microstructure characterization of high chromium cast irons

    Institute of Scientific and Technical Information of China (English)

    J.T.H. Pearce; T. Chairuangsri; A. Wiengmoon; N. Poolthong; H. Nomura

    2007-01-01

    The physical metallurgy underlying the development of cast microstructures in abrasion resistant high chromium cast irons, and their structural modification by thermal treatments is relatively complex. Structural characterisation via electron microscopy therefore has a key role to play in furthering our understanding of the phase transformations that control the microstructures and hence the service performances of these irons as wear parts.This paper shows how both scanning and especially transmission electron microscopy can provide valuable information on the nature of eutectic and secondary carbides and on the matrix structures in these irons. Particular attention is given to current characterisation research on conventionally cast 30%Cr irons that are used for applications involving corrosive wear e.g. slurry pumps and on a semi-solid cast 27%Cr iron that has a potential for applications in industry.

  1. Mechanism of Arsenic Sequestration in High-Iron Sediments

    Science.gov (United States)

    Root, R. A.; Campbell, K. M.; Hering, J. G.; O'Day, P. A.

    2005-12-01

    Naturally occurring elevated concentrations of arsenic in the runoff of the eastern Sierra Nevada and feed waters of the Los Angeles Aqueduct are remediated by the Los Angeles Department of Power and Water (LADPW) up stream of the Haiwee Reservoir (Olancha, CA). To reduce total arsenic in drinking water supplies, the LADPW adds ferric chloride and a cationic polymer coagulant to the aqueduct. The treatment precipitates as an amorphous iron oxide, spectrally similar to 6-line ferrihydrite, that adsorbs and sequesters arsenic as arsenate. As the channeled flow enters North Haiwee Reservoir, the As(V)-enriched iron floc settles as sediments in the inlet channel. Buried As(V) is reduced to As(III) near the sediment-water interface (0-10cm), and only As(III) is observed at depths below the steep (1-2cm) near-surface redox gradient. Sediment samples from 30-cm push cores were collected from the edge of the reservoir along the inlet channel in tandem with in situ porewater measurements using an inert polyacrylamide gel probe sampler. Sediments were analyzed to characterize the redox gradient, host mineralogy, and variation in bulk elemental composition with depth. X-ray absorption spectroscopy (XAS) was used to determine the depth of the microbially driven redox boundary where As (V) is reduced to As (III) and to investigate the molecular bonding of arsenic adsorbed to iron hydroxide surfaces. Specific and characteristic iron and arsenic phases were isolated by sequential extraction; extracted and bulk concentrations were determined by ICP-MS. Splits of specific extraction steps were analyzed by synchrotron EXAFS and XRD to determine the identity of separated phases. The primary mineralogy of sediments along the inlet channel is detrital quartz, plagioclase feldspar, and phyllosilicates weathered from the Sierra Nevada granitic batholith. Notably, crystalline magnetite, hematite, and goethite, phases that would indicate transformation of hydrous iron phases to more stable

  2. Combined deficiency of iron and (n-3) fatty acids in male rats disrupts brain monoamine metabolism and produces greater memory deficits than iron deficiency or (n-3) fatty acid deficiency alone1-3

    OpenAIRE

    Baumgartner, Jeannine; Smuts, Cornelius M; Malan, Linda; Arnold, Myrtha; Yee, Benjamin K.

    2012-01-01

    Deficiencies of iron (Fe) (ID) and (n-3) fatty acids (FA) [(n-3)FAD] may impair brain development and function through shared mechanisms. However, little is known about the potential interactions between these 2 common deficiencies. We studied the effects of ID and (n-3)FAD, alone and in combination, on brain monoamine pathways (by measuring monoamines and related gene expression) and spatial working and reference memory (by Morris water maze testing). Using a 2 × 2 design, male rats were fed...

  3. Age-related changes of brain iron load changes in the frontal cortex in APPswe/PS1ΔE9 transgenic mouse model of Alzheimer's disease.

    Science.gov (United States)

    Xian-hui, Dong; Wei-juan, Gao; Tie-mei, Shao; Hong-lin, Xie; Jiang-tao, Bai; Jing-yi, Zhao; Xi-qing, Chai

    2015-04-01

    Alzheimer's disease (AD) as a neurodegenerative brain disorder is a devastating pathology leading to disastrous cognitive impairments and dementia, associated with major social and economic costs to society. Iron can catalyze damaging free radical reactions. With age, iron accumulates in brain frontal cortex regions and may contribute to the risk of AD. In this communication, we investigated the age-related brain iron load changes in the frontal cortex of 6- and 12-month-old C57BL/6J (C57) and APPswe/PS1ΔE9 (APP/PS1) double transgenic mouse by using graphite furnace atomic absorption spectrometry (GFAAS) and Perls' reaction. In the present study, we also evaluated the age-related changes of DMT1 and FPN1 by using Western blot and qPCR. We found that compared with 6-month-old APP/PS1 mice and the 12-month-old C57 mice, the 12-month-old APP/PS1 mice had increased iron load in the frontal cortex. The levels of DMT1 were significantly increased and the FPN1 were significantly reduced in the frontal cortex of the 12-month-old APP/PS1 mice than that in the 6-month-old APP/PS1 mice and 12-month-old C57 mice. We conclude that in AD damage occurs in conjunction with iron accumulation, and the brain iron load associated with loss control of the brain iron metabolism related protein DMT1 and FPN1 expressions.

  4. Human serum transferrin: Is there a link between autism, high oxalate and iron deficiency anemia?

    Science.gov (United States)

    Luck, Ashley N.; Bobst, Cedric E.; Kaltashov, Igor A.; Mason, Anne B.

    2013-01-01

    It has been previously suggested that high amounts of oxalate in plasma could play a role in autism by binding to the bilobal iron transport protein transferrin (hTF) thereby interfering with iron metabolism by inhibiting iron delivery to cells. By examining the effect of the substitution of oxalate for the physiologically utilized synergistic carbonate anion in each lobe of hTF we sought to provide a molecular basis for or against such a role. Our work clearly shows both qualitatively (6 M urea gels) and quantitatively (kinetic analysis by stop flow spectrofluorimetry) that the presence of oxalate in place of carbonate in each binding site of hTF does indeed greatly interfere with iron removal from each lobe (both in the absence and presence of the specific hTF receptor). However, we also clearly demonstrate that once the iron is bound within each lobe of hTF, neither anion can displace the other. Additionally, as verified by urea gels and electrospray mass spectrometry, formation of completely homogeneous hTF-anion complexes requires that all iron must first be removed and hTF then reloaded with iron in the presence of either carbonate or oxalate. Of significance, experiments described herein show that carbonate is the preferred binding partner, i.e., even if an equal amount of each anion is available during the iron loading process the hTF-carbonate complex is formed. PMID:24152109

  5. Effects of High Dietary HEME Iron and Radiation on Cardiovascular Function

    Science.gov (United States)

    Westby, Christian M.; Brown, A. K.; Platts, S. H.

    2012-01-01

    The radiation related health risks to astronauts is of particular concern to NASA. Data support that exposure to radiation is associated with a number of disorders including a heightened risk for cardiovascular diseases. Independent of radiation, altered nutrient status (e.g. high dietary iron) also increases ones risk for cardiovascular disease. However, it is unknown whether exposure to radiation in combination with high dietary iron further increases ones cardiovascular risk. The intent of our proposal is to generate compulsory data examining the combined effect of radiation exposure and iron overload on sensitivity to radiation injury to address HRP risks: 1) Risk Factor of Inadequate Nutrition; 2) Risk of Cardiac Rhythm Problems; and 3) Risk of Degenerative Tissue or other Health Effects from Space Radiation. Towards our goal we propose two distinct pilot studies using the following specific aims: Vascular Aim 1: To determine the short-term consequences of the independent and combined effects of exposure to gamma radiation and elevated body iron stores on measures of endothelial function and cell viability and integrity. We hypothesize that animals that have high body iron stores and are exposed to gamma radiation will show a greater reduction in endothelial dependent nitric oxid production and larger pathological changes in endothelial integrity than animals that have only 1 of those treatments (either high iron stores or exposure to gamma radiation). Vascular Aim 2: Identify and compare the effects of gamma radiation and elevated body iron stores on the genetic and epigenetic regulation of proteins associated with endothelial cell function. We hypothesize that modifications of epigenetic control and posttranslational expression of proteins associated with endothelial cell function will be differentially altered in rats with high body iron stores and exposed to gamma radiation compared to rats with only 1 type of treatment. Cardiac Aim 1: To determine the

  6. A comparison of MRI tissue relaxometry and ROI methods used to determine regional brain iron concentrations in restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Moon HJ

    2015-07-01

    Full Text Available Hye-Jin Moon,1,* Yongmin Chang,2,* Yeong Seon Lee,1 Huijin Song,3 Hyuk Won Chang,4 Jeonghun Ku,5 Richard P Allen,6 Christopher J Earley,6 Yong Won Cho1 1Department of Neurology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Republic of Korea; 2Department of Molecular Medicine, 3Department of Medical and Biological Engineering, Kyungpook National University and Hospital, Daegu, Republic of Korea; 4Department of Radiology, 5Department of Biomedical Engineering, School of Medicine, Keimyung University, Daegu, Republic of Korea; 6Department of Neurology, Johns Hopkins University, Hopkins Bayview Medical Center, Baltimore, MD, USA *These authors contributed equally to this work Purpose: Magnetic resonance imaging relaxometry studies differed on the relaxometry methods and their approaches to determining the regions of interest (ROIs in restless legs syndrome (RLS patients. These differences could account for the variable and inconsistent results found across these studies. The aim of this study was to assess the relationship between the different relaxometry methods and different ROI approaches using each of these methods on a single population of controls and RLS subjects. Methods: A 3.0-T magnetic resonance imaging with the gradient-echo sampling of free induction decay and echo pulse sequence was used. The regional brainiron concentrations” were determined using three relaxometry metrics (R2, R2*, and R2' through two different ROI methods. The substantia nigra (SN was the primary ROI with red nucleus, caudate, putamen, and globus pallidus as the secondary ROIs. Results: Thirty-seven RLS patients and 40 controls were enrolled. The iron concentration as determined by R2 did not correlate with either of the other two methods, while R2* and R2' showed strong correlations, particularly for the substantia nigra and red nucleus. In the fixed-shape ROI method, the RLS group showed a lower iron index compared to the control

  7. C19orf12 and FA2H mutations are rare in Italian patients with neurodegeneration with brain iron accumulation.

    Science.gov (United States)

    Panteghini, Celeste; Zorzi, Giovanna; Venco, Paola; Dusi, Sabrina; Reale, Chiara; Brunetti, Dario; Chiapparini, Luisa; Zibordi, Federica; Siegel, Birgit; Siegel, Brigitte; Garavaglia, Barbara; Simonati, Alessandro; Bertini, Enrico; Nardocci, Nardo; Tiranti, Valeria

    2012-06-01

    Neurodegeneration with brain iron accumulation (NBIA) defines a wide spectrum of clinical entities characterized by iron accumulation in specific regions of the brain, predominantly in the basal ganglia. We evaluated the presence of FA2H and C19orf12 mutations in a cohort of 46 Italian patients with early onset NBIA, which were negative for mutations in the PANK2 and PLA2G6 genes. Follow-up molecular genetic and in vitro analyses were then performed. We did not find any mutations in the FA2H gene, although we identified 3 patients carrying novel mutations in the C19orf12 gene. The recent discovery of new genes responsible for NBIA extends the spectrum of the genetic investigation now available for these disorders and makes it possible to delineate a clearer clinical-genetic classification of different forms of this syndrome. A large fraction of patients still remain without a molecular genetics diagnosis, suggesting that additional NBIA genes are still to be discovered.

  8. RESEARCH AND APPLICATION OF AS-CAST WEAR RESISTANCE HIGH CHROMIUM CAST IRON

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The influence of alloy elements, such as boron and silicon, on the microstructure and properties of as-cast high chromium cast iron is studied. The results show that boron and silicon have a great effect on the mechanical properties and the wear resistance. Through proper addition of boron and silicon, the properties of as-cast high chromium cast iron can be improved effectively. Through analyzing the distribution of elements by scanning electron microscope, it has been shown that the addition of boron and silicon lowers the mass fraction of chromium saturated in as-cast austenite, and makes it unstable and liable to be transformed into martensite. The as-cast high chromium cast iron with proper content of boron and silicon is suitable for the manufacture of lining for asphalt concrete mixer and its wear resistance is 14 times that of lining made of low alloy white cast iron.

  9. Combined deficiency of iron and (n-3) fatty acids in male rates disrupts brain monoamine metabolism and produces greater memory deficits than iron deficiency or (n-3) fatty acid deficiency alone

    NARCIS (Netherlands)

    Baumgartner, J.; Smuts, C.M.; Malan, L.; Arnold, M.; Yee, B.K.; Bianco, L.E.; Boekschoten, M.V.; Muller, M.R.; Langhans, W.; Hurrell, R.F.; Zimmermann, M.B.

    2012-01-01

    Deficiencies of iron (Fe) (ID) and (n-3) fatty acids (FA) [(n-3)FAD] may impair brain development and function through shared mechanisms. However, little is known about the potential interactions between these 2 common deficiencies. We studied the effects of ID and (n-3)FAD, alone and in combination

  10. Iron Abundance Diagnostics in High-Redshift QSOs

    CERN Document Server

    Corbin, M R; Freduling, N K W; Corbin, Michael R.; Korista, Kirk T.; Freduling, Nalaka Kodituwakku & Wolfram

    2004-01-01

    The abundance of alpha-process elements such as magnesium and carbon relative to iron measured from the broad emission lines of QSOs can serve as a diagnostic of the star formation and chemical enrichment histories of their host galaxies. We investigate the relationship between Fe/Mg and Fe/C abundance ratios and the resulting Fe II / Mg II 2800A and Fe II / 1900A-blend flux ratios, both of which have been measured in QSOs out to redshifts of approximately six. Using a galactic chemical evolution model based on a starburst in a giant elliptical galaxy, we find that these flux ratios are good tracers of the chemical enrichment of the nuclei. However, the values of these ratios measured in objects at redshifts of approximately six suggest that iron enrichment has occurred more rapidly in these objects than predicted by the assumed elliptical starburst model, under currently favored cosmologies.

  11. Biomonitorization of iron accumulation in the substantia nigra from Lewy body disease patients

    Science.gov (United States)

    Fernández, Belén; Ferrer, Isidro; Gil, Fernando; Hilfiker, Sabine

    2017-01-01

    Iron levels in the healthy human brain are known to be high in certain areas such as the substantia nigra (SN), and increase further with age. In addition, there is some evidence for a further increase in iron load in the SN of Parkinson's disease (PD) patients as compared to controls, which correlates with motor disability. Here, we have analyzed total iron levels in cells as well as mouse and human brain samples by atomic absorption spectroscopy (AAS). Our data indicate that iron load is more pronounced in cells with dopaminergic features. Moreover, region-specific differences in iron load reflecting those in the human brain were detected in rodent brains as well. Whilst altered iron load was not observed in other regions also affected in PD patients, we report a significant increase in iron load in the SN of Lewy body disease patients as compared to Alzheimer's disease (AD) patients or controls, which correlates with neurodegeneration in this brain area. PMID:28529891

  12. Hydrogen embrittlement on {alpha}-iron in high alkaline environment

    Energy Technology Data Exchange (ETDEWEB)

    Hu, R.; Habashi, M.; Galland, J. [Ecole Central Paris, Chatenay-Malabry (France)

    1994-12-31

    The partial pressure of hydrogen in concrete`s pore is very low. This hydrogen is due to the chemical reaction between the silica fumes and the alkaline solutions filling the concrete`s pore. Silica fumes are added in the concrete to increase its compression resistance. If the hydrogen pressure is low, the risk of hydrogen embrittlement is also low. However, for constructional works destined to endure more than 50 years, is this risk negligible? To answer this question, the authors have studied the hydrogen embrittlement on {alpha}-iron in alkaline solutions, in the pH range 9.5 to 13.3, presenting the liquids found in the concrete`s pores after different aging, periods. Cathodic charging has been performed for low current densities in the range 0.25 to 90 A/m{sup 2} simulating several partial pressures of hydrogen on the {alpha}-iron surface with and without EDTA inhibitor. The deformation rate was 2.5{times}10{sup {minus}5} s{sup {minus}1}. Finally {alpha}-iron samples and tensile specimens have been immersed in a mixture of silica fumes and an alkaline solution at pH 13.3 in an autoclave during 1,000 hours with the aim to measure the outgassed quantity of hydrogen under vacuum at 600C and to measure also the hydrogen embrittlement. The main conclusions of this study are as following: (1) Hydrogen embrittlement is promoted by oxide Fe{sub 3}O{sub 4} film rupture and/or hydroxide Fe(OH){sub 2}. This mechanism is efficient for current densities equivalent to a cathodic potential lower or equal to {minus}1V/NHE. (2) Silica fumes in contact with a solution of pH 13.3 provoke hydrogen release and its diffusion into the {alpha}-iron, but this quantity is not enough to embrittle it.

  13. Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function

    Science.gov (United States)

    Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

    2012-01-01

    Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of: (1) peripheral leukocyte distribution, (2) plasma cytokine levels and (3) cytokine production profiles following whole blood mitogenic stimulation

  14. Abrasion Resistance of as-Cast High-Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Pokusová Marcela

    2014-12-01

    Full Text Available High chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.% 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

  15. Elevated levels of iron in groundwater in Prey Veng province in Cambodia: a possible factor contributing to high iron stores in women.

    Science.gov (United States)

    Karakochuk, Crystal D; Murphy, Heather M; Whitfield, Kyly C; Barr, Susan I; Vercauteren, Suzanne M; Talukder, Aminuzzaman; Porter, Keith; Kroeun, Hou; Eath, Many; McLean, Judy; Green, Timothy J

    2015-06-01

    Iron is a natural element found in food, water and soil and is essential for human health. Our aim was to determine the levels of iron and 25 other metals and trace elements in groundwater from 22 households in Prey Veng, Cambodia. Water analyses were conducted using inductively coupled plasma-mass spectrometry and optical emission spectrometry. Compared to the 2011 World Health Organization guidelines for drinking water quality, aluminum, iron and manganese exceeded maximum levels (in 4.5, 72.7 and 40.9% of samples, respectively). Compared to the 2004 Cambodian drinking water quality standards, iron and manganese exceeded maximum levels (in 59.1 and 36.4% of samples, respectively). We found no evidence of arsenic contamination. Guidelines for iron were established primarily for esthetic reasons (e.g. taste), whereas other metals and elements have adverse effects associated with toxicity. Iron in groundwater ranged from 134 to 5,200 μg/L (mean ∼1,422 μg/L). Based on a daily consumption of 3 L groundwater, this equates to ∼0.4-15.6 mg iron (mean ∼4.3 mg/day), which may be contributing to high iron stores and the low prevalence of iron deficiency anemia in Prey Veng women. Elevated levels of manganese in groundwater are a concern and warrant further investigation.

  16. Response of Streptococcus suis to iron-restricted growth conditions at high and low oxygen availability.

    Science.gov (United States)

    Winterhoff, Nora; Goethe, Ralph; Gruening, Petra; Valentin-Weigand, Peter

    2004-01-01

    Streptococcus suis (S. suis) is an important pathogen in pigs and has to overcome strict iron limitations in its host environment. Here, we studied iron-restricted growth of a highly virulent S. suis strain in vitro at aerobic and CO2-enriched growth conditions. At both conditions, depleting of iron in the culture medium with nitrilotriacetic acid (NTA) resulted in decreased growth rates and down regulation of several proteins. Sensitivity to NTA was significantly higher at aerobic versus CO2-enriched conditions. Growth could not be restored by addition of host iron sources such as ferritin, hemin, hemoglobin, lactoferrin or transferrin. Accordingly, S. suis was not able to produce detectable amounts of siderophores. On the other hand, growth at iron-restricted conditions was fully restored by addition of Mn2+ (at aerobic and CO2-enriched conditions) or Mg2+ (only at CO2-enriched conditions). In conclusion our results suggest that, unlike many other bacteria, S. suis adapts to iron restricted conditions by a change in its metabolism in order to replace Fe2+ by Mn2+ or Mg2+ rather than by expressing specific iron uptake systems.

  17. Synthesis and spectroscopic characterization of high-spin mononuclear iron(II) p-semiquinonate complexes.

    Science.gov (United States)

    Baum, Amanda E; Park, Heaweon; Lindeman, Sergey V; Fiedler, Adam T

    2014-12-01

    Two mononuclear iron(II) p-semiquinonate (pSQ) complexes have been generated via one-electron reduction of precursor complexes containing a substituted 1,4-naphthoquinone ligand. Detailed spectroscopic and computational analysis confirmed the presence of a coordinated pSQ radical ferromagnetically coupled to the high-spin Fe(II) center. The complexes are intended to model electronic interactions between (semi)quinone and iron cofactors in biology.

  18. Synthesis and Spectroscopic Characterization of High-Spin Mononuclear Iron(II) p-Semiquinonate Complexes

    OpenAIRE

    Baum, Amanda E.; Park, Heaweon; Lindeman, Sergey V.; Fiedler, Adam T.

    2014-01-01

    Two mononuclear iron(II) p-semiquinonate (pSQ) complexes have been generated via one-electron reduction of precursor complexes containing a substituted 1,4-naphthoquinone ligand. Detailed spectroscopic and computational analysis confirmed the presence of a coordinated pSQ radical ferromagnetically coupled to the high-spin FeII center. The complexes are intended to model electronic interactions between (semi)quinone and iron cofactors in biology.

  19. XPS and FTIR spectroscopic study on microwave treated high phosphorus iron ore

    Energy Technology Data Exchange (ETDEWEB)

    Omran, Mamdouh, E-mail: mamdouh.omran@oulu.fi [Process Metallurgy Research Group, Faculty of Technology, University of Oulu (Finland); Mineral Processing and Agglomeration Lab, Central Metallurgical Research and Development Institute, Cairo (Egypt); Fabritius, Timo [Process Metallurgy Research Group, Faculty of Technology, University of Oulu (Finland); Elmahdy, Ahmed M.; Abdel-Khalek, Nagui A. [Mineral Processing and Agglomeration Lab, Central Metallurgical Research and Development Institute, Cairo (Egypt); El-Aref, Mortada; Elmanawi, Abd El-Hamid [Geology Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

    2015-08-01

    Highlights: • The effect of microwave radiation on structure and chemical state of high phosphorus iron ore was studied. • FTIR analyses showed that after microwave radiation the functional chemical groups of phosphorus bearing minerals (fluorapatite) dissociated. • High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). • Microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases. - Abstract: A growing interest in microwave heating has emerged recently. Several potential microwave applications regarding minerals’ processing have been investigated. This paper investigates the effect of microwave radiation on Egyptian high phosphorus iron ore. Three different iron ore samples have varying Fe{sub 2}O{sub 3} and P{sub 2}O{sub 5} contents and mineralogical textures were studied. A comparative study has been carried out between untreated and microwave treated iron ore. XRD and FTIR analyses showed that after microwave radiation the crystallinity of iron bearing minerals (hematite) increased, while the functional chemical groups of phosphorus bearing minerals (fluorapatite) and other gangues dissociated. High resolution XPS analyses of Fe 2p peaks showed that after microwave radiation a portion of Fe(+III) was reduced to Fe(+II). This means that after microwave radiation iron oxide (hematite, Fe{sup 3+}) transformed into more magnetic phase. The results indicated that microwave radiation had a positive effect on the magnetic properties of iron oxide, through formation of ferromagnetic phases.

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

    Science.gov (United States)

    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.

  1. [Adult-onset case of idiopathic neurodegeneration with brain iron accumulation without mutations in the PANK2 and PLA2G6 genes].

    Science.gov (United States)

    Saiki, Shinji; Sekine, Takeshi; Ueno, Yuji; Yoshino, Hiroyo; Takahashi, Junko; Tani, Yoshihiko; Kambe, Yasunori; Motoi, Yumiko; Hattori, Nobutaka

    2009-08-01

    A 47-year-old man with a 15-year history of bipolar disorder treated with anti-depressants, lithium carbonate or neuroleptics was admitted because of marked difficulty in gait and speech. At the age 45, he was unable to walk without bilateral assists and became a wheel-chair state. There was no family history and his mother, father and younger sister were neurologically free. General physical examinations revealed no abnormalities. Neurologically, he was moderately demented (mini mental state examination: 18/30) and showed bilateral horizontal gaze nystagmus, parkinsonism, cerebellar ataxia, dysarthria and moderate spastic paraparesis. No involuntary movements were noted. Wet blood smear showed acanthocytes, while blood chemistries revealed no abnormalities including levels of serum creatine kinase, hepatic enzymes and blood beta-lipoprotein. Kell antigen expressions of the red blood cells were within normal limit. Western blot analysis with anti-chorein antibody detected normal chorein expression levels of the red blood cells. Cranial MRI showed severe symmetric atrophy of the frontotemporal lobes, caudate nuclei, putamen, and brainstem. Also, MRI-gradient echo showed symmetric iron accumulation in the medial portion of the globus pallidus without surrounding high intensity areas, so called "eye-of-the-tiger sign". Genetic analyses revealed no mutations in the PANK2 and PLA2G6 genes. Therefore, he was diagnosed as idiopathic neurodegeneration with brain iron accumulation (NBIA). These findings suggest that NBIA is heterogeneous and other additional genes remain to be found.

  2. Iron deficiency.

    Science.gov (United States)

    Scrimshaw, N S

    1991-10-01

    The world's leading nutritional problem is iron deficiency. 66% of children and women aged 15-44 years in developing countries have it. Further, 10-20% of women of childbearing age in developed countries are anemic. Iron deficiency is identified with often irreversible impairment of a child's learning ability. It is also associated with low capacity for adults to work which reduces productivity. In addition, it impairs the immune system which reduces the body's ability to fight infection. Iron deficiency also lowers the metabolic rate and the body temperature when exposed to cold. Hemoglobin contains nearly 73% of the body's iron. This iron is always being recycled as more red blood cells are made. The rest of the needed iron does important tasks for the body, such as binds to molecules that are reservoirs of oxygen for muscle cells. This iron comes from our diet, especially meat. Even though some plants, such as spinach, are high in iron, the body can only absorb 1.4-7% of the iron in plants whereas it can absorb 20% of the iron in red meat. In many developing countries, the common vegetarian diets contribute to high rates of iron deficiency. Parasitic diseases and abnormal uterine bleeding also promote iron deficiency. Iron therapy in anemic children can often, but not always, improve behavior and cognitive performance. Iron deficiency during pregnancy often contributes to maternal and perinatal mortality. Yet treatment, if given to a child in time, can lead to normal growth and hinder infections. However, excess iron can be damaging. Too much supplemental iron in a malnourished child promotes fatal infections since the excess iron is available for the pathogens use. Many countries do not have an effective system for diagnosing, treating, and preventing iron deficiency. Therefore a concerted international effort is needed to eliminate iron deficiency in the world.

  3. Optimizing superparamagnetic iron oxide nanoparticles as drug carriers using an in vitro blood–brain barrier model

    Science.gov (United States)

    Shi, Di; Mi, Gujie; Bhattacharya, Soumya; Nayar, Suprabha; Webster, Thomas J

    2016-01-01

    In the current study, an optimized in vitro blood–brain barrier (BBB) model was established using mouse brain endothelial cells (b.End3) and astrocytes (C8-D1A). Before measuring the permeability of superparamagnetic iron oxide nanoparticle (SPION) samples, the BBB was first examined and confirmed by an immunofluorescent stain and evaluating the transendothelial electrical resistance. After such confirmation, the permeability of the following five previously synthesized SPIONs was determined using this optimized BBB model: 1) GGB (synthesized using glycine, glutamic acid, and bovine serum albumin [BSA]), 2) GGC (glycine, glutamic acid, and collagen), 3) GGP (glycine, glutamic acid, and polyvinyl alcohol), 4) BPC (BSA, polyethylene glycol, and collagen), and 5) CPB (collagen, polyvinyl alcohol, and BSA). More importantly, after the permeability test, transmission electron microscopy thin section technology was used to investigate the mechanism behind this process. Transmission electron microscopy thin section images supported the hypothesis that collagen-coated CPB SPIONs displayed better cellular uptake than glycine and glutamine acid-coated GGB SPIONs. Such experimental data demonstrated how one can modify SPIONs to better deliver drugs to the brain to treat a wide range of neurological disorders.

  4. Certain types of iron oxide nanoparticles are not suited to passively target inflammatory cells that infiltrate the brain in response to stroke

    Science.gov (United States)

    Harms, Christoph; Datwyler, Anna Lena; Wiekhorst, Frank; Trahms, Lutz; Lindquist, Randall; Schellenberger, Eyk; Mueller, Susanne; Schütz, Gunnar; Roohi, Farnoosh; Ide, Andreas; Füchtemeier, Martina; Gertz, Karen; Kronenberg, Golo; Harms, Ulrike; Endres, Matthias; Dirnagl, Ulrich; Farr, Tracy D

    2013-01-01

    Intravenous administration of iron oxide nanoparticles during the acute stage of experimental stroke can produce signal intensity changes in the ischemic region. This has been attributed, albeit controversially, to the infiltration of iron-laden blood-borne macrophages. The properties of nanoparticles that render them most suitable for phagocytosis is a matter of debate, as is the most relevant timepoint for administration. Both of these questions are examined in the present study. Imaging experiments were performed in mice with 30 minutes of middle cerebral artery occlusion (MCAO). Iron oxide nanoparticles with different charges and sizes were used, and mice received 300 μmol Fe/kg intravenously: either superparamagnetic iron oxide nanoparticles (SPIOs), ultrasmall SPIOs, or very small SPIOs. The particles were administered 7 days before MCAO, at the time of reperfusion, or 72 hours after MCAO. Interestingly, there was no observable signal change in the ischemic brains that could be attributed to iron. Furthermore, no Prussian blue-positive cells were found in the brains or blood leukocytes, despite intense staining in the livers and spleens. This implies that the nanoparticles selected for this study are not phagocytosed by blood-borne leukocytes and do not enter the ischemic mouse brain. PMID:23443176

  5. Chemical classification of iron meteorites. XI - Multi-element studies of 38 new irons and the high abundance of ungrouped irons from Antarctica

    Science.gov (United States)

    Wasson, John T.; Ouyang, Xinwei; Wang, Jianmin; Jerde, Eric

    1989-01-01

    Concentrations of 14 elements in the metal of 38 iron meteorites and a pallasite are reported. Three samples are paired with previously classified irons, raising the number of well-classified, independent iron meteorites to 598. Several of the new irons are from Antarctica. Of 24 independent irons from Antarctica, eight are ungrouped, a much higher fraction than that among all classified irons. The difference is probably related to the fact that the median mass of Antarctic irons is about two orders of magnitude smaller than that of non-Antarctic irons. Smaller meteoroids may tend to sample a larger number of asteroidal source regions, perhaps because small meteoroids tend to have higher ejection velocities or because they have random-walked a greater increment of orbital semimajor axis away from that of the parent body.

  6. Production of Low-Phosphorus Molten Iron from High-Phosphorus Oolitic Hematite Using Biomass Char

    Science.gov (United States)

    Tang, Huiqing; Qi, Tengfei; Qin, Yanqi

    2015-09-01

    In this study, an energy-saving and environmentally friendly method to produce low-phosphorus molten iron from high-phosphorus oolitic hematite was experimentally investigated and theoretically analyzed. The results indicate that biomass char is a suitable reducing agent for the proposed method. In the direct reduction stage, the ore-char briquette reached a metallization degree of 80-82% and a residual carbon content of 0.1-0.3 mass%. Under the optimized condition, phosphorus remained in the gangue as calcium phosphate. In the melting separation stage, phosphorus content ([%P]) in molten iron could be controlled by introducing a Na2CO3 additive, and the phosphorus behavior could be predicted using ion molecular coexistence theory. Molten iron with [%P] less than 0.3 mass% was obtained from the metallic briquettes with the aforementioned quality by introducing 2-4% Na2CO3 and the iron recovery rate was 75-78%.

  7. High-resolution X-ray absorption spectroscopy of iron carbonyl complexes.

    Science.gov (United States)

    Atkins, Andrew J; Bauer, Matthias; Jacob, Christoph R

    2015-06-07

    We apply high-energy-resolution fluorescence-detected (HERFD) X-ray absorption near-edge spectroscopy (XANES) to study iron carbonyl complexes. Mono-, bi-, and tri-nuclear carbonyl complexes and pure carbonyl complexes as well as carbonyl complexes containing hydrocarbon ligands are considered. The HERFD-XANES spectra reveal multiple pre-edge peaks with individual signatures for each complex, which could not be detected previously with conventional XANES spectroscopy. These peaks are assigned and analysed with the help of TD-DFT calculations. We demonstrate that the pre-edge peaks can be used to distinguish the different types of iron-iron interactions in carbonyl complexes. This opens up new possibilities for applying HERFD-XANES spectroscopy to probe the electronic structure of iron catalysts.

  8. Calorie restriction down-regulates expression of the iron regulatory hormone hepcidin in normal and D-galactose-induced aging mouse brain.

    Science.gov (United States)

    Wei, Shougang; Shi, Wenli; Li, Man; Gao, Qian

    2014-02-01

    It has been shown that iron progressively accumulates in the brain with age. Calorie restriction (CR) may allay many of the adverse effects of aging on the brain, yet the underlying mechanisms, in particular in relation to brain iron metabolism, remain unclear. This study aimed to investigate the role of CR in the regulation of cerebral cellular iron homeostasis. C57BL/6 mice were randomly divided into four groups of eight. The control group was fed a conventional diet ad libitum; the CR group received 70% of the calories of the control mouse intake per day; the D-galactose (D-gal) group received subcutaneous injection of D-gal at a dose of 100 mg/kg once daily to produce mouse model of aging; the D-gal plus CR group received both of the two interventions for 14 weeks. The Morris water maze (MWM) was employed to test the cognitive performance of all animals, and the expression of iron regulatory genes, ferroportin and hepcidin, in the cortex and hippocampus were detected by quantitative real-time PCR. Compared to the controls, the D-gal group mice showed significant spatial reference memory deficits in the MWM test, whereas the D-gal-CR group mice exhibited almost normal cognitive function, indicating that CR protects against D-gal-induced learning and memory impairment. Hepcidin mRNA expression was increased in the D-gal group, decreased in the CR group, and was basically unchanged in the D-gal-CR group. There was no statistical difference in the transmembrane iron exporter ferroportin expression between control and any of the experimental groups. The results suggest that the anti-aging effects of CR might partially lie in its capacity to reduce or avoid age-related iron accumulation in the brain through down-regulating expression of brain hepcidin--the key negative regulator for intracellular iron efflux--and that facilitating the balance of brain iron metabolism may be a promising anti-aging measure.

  9. Brain antioxidant responses to acute iron and copper intoxications in rats.

    Science.gov (United States)

    Semprine, Jimena; Ferrarotti, Nidia; Musacco-Sebio, Rosario; Saporito-Magriñá, Christian; Fuda, Julián; Torti, Horacio; Castro-Parodi, Mauricio; Damiano, Alicia; Boveris, Alberto; Repetto, Marisa G

    2014-11-01

    Dose- and time-dependent antioxidant responses to Fe (0-60 mg kg(-1)) and Cu overloads (0-30 mg kg(-1)) in rat brains are described by the C50 and the t1/2, the brain metal concentration and the time for half maximal oxidative responses. Brain GSH and the GSH/GSSG ratio markedly decreased after Fe and Cu treatments (50-80%) with a t1/2 of 9-10 h for GSH and of 4 h for GSH/GSSG for both metals. The GSH/GSSG ratio was the most sensitive indicator of brain oxidative stress. The decrease of GSH and the increase of in vivo chemiluminescence had similar time courses. The C50 for brain chemiluminescence, GSH and hydrophilic and lipophilic antioxidants were in similar ranges (32-36 μg Fe g(-1) brain and 10-18 μg Cu g(-1) brain), which indicated a unique free-radical mediated process for each metal. The brain concentration of hydrophilic and lipophilic antioxidants decreased after Fe and Cu loads; hydrophilic antioxidants decreased by 46-68% with a t1/2 of 10-11 h and lipophilic antioxidants decreased by 75-45% with a t1/2 of 10-12 h. Cu,Zn-SOD and CAT activities and the protein expression were adaptively increased (100-90% after Fe and Cu loads), with a t1/2 of 8-12 h. GPx-4 activity decreased after both metal loads by 73-27% with a t1/2 of 8-4 h with decreased protein expression.

  10. Magnetic resonance imaging of post-ischemic blood-brain barrier damage with PEGylated iron oxide nanoparticles

    Science.gov (United States)

    Liu, Dong-Fang; Qian, Cheng; An, Yan-Li; Chang, Di; Ju, Sheng-Hong; Teng, Gao-Jun

    2014-11-01

    Blood-brain barrier (BBB) damage during ischemia may induce devastating consequences like cerebral edema and hemorrhagic transformation. This study presents a novel strategy for dynamically imaging of BBB damage with PEGylated supermagnetic iron oxide nanoparticles (SPIONs) as contrast agents. The employment of SPIONs as contrast agents made it possible to dynamically image the BBB permeability alterations and ischemic lesions simultaneously with T2-weighted MRI, and the monitoring could last up to 24 h with a single administration of PEGylated SPIONs in vivo. The ability of the PEGylated SPIONs to highlight BBB damage by MRI was demonstrated by the colocalization of PEGylated SPIONs with Gd-DTPA after intravenous injection of SPION-PEG/Gd-DTPA into a mouse. The immunohistochemical staining also confirmed the leakage of SPION-PEG from cerebral vessels into parenchyma. This study provides a novel and convenient route for imaging BBB alteration in the experimental ischemic stroke model.

  11. Compact and mobile high resolution PET brain imager

    Science.gov (United States)

    Majewski, Stanislaw; Proffitt, James

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  12. TO SELECTION OF TECHNOLOGICAL SCHEME OF SOFTENING HEAT TREATMENT FOR HIGH CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    V. G. Efremenko

    2014-03-01

    Full Text Available Purpose. High chromium cast irons with austenitic matrix have low machinability. The aim of work is search of new energy-saving modes of preliminary softening heat treatment enhancing the machinability of castings by forming an optimum microstructure. Methodology. Metallographic analysis, hardness testing and machinability testing are applied. Findings. It was found out that high temperature annealing with continuous cooling yields to martensite-austenite matrix in cast iron 270Х15Г2Н1MPhT, which abruptly affects the machinability of cast iron. Significant improvement of machinability is achieved by forming of structure "ferrite + granular carbides" and by decline of hardness to 37-39 HRC in the case of two-stage isothermal annealing in the subcritical temperature range or by the use of quenching and tempering (two-step or cyclic. Originality. It was found that the formation of the optimal structure of the matrix and achievement of desired hardness level needed for improving machinability of high chromium cast iron containing 3 % austenite-forming elements, can be obtained: 1 due to pearlite original austenite followed by spherodization eutectoid carbides, and 2 by getting predominantly martensite structure followed by the decay of martensite and carbides coagulation at high-temperature tempering. Practical value. The new energy-saving schemes of softening heat treatment to ensure the growth of machinability of high chromium cast iron, alloyed by higher quantity of austenite forming elements, are proposed.

  13. Antioxidant and iron-binding properties of curcumin, capsaicin, and S-allylcysteine reduce oxidative stress in rat brain homogenate.

    Science.gov (United States)

    Dairam, Amichand; Fogel, Ronen; Daya, Santy; Limson, Janice L

    2008-05-14

    Research demonstrates that antioxidants and metal chelators may be of beneficial use in the treatment of neurodegenerative diseases, such as Alzheimer's disease (AD). This study investigated the antioxidant and metal-binding properties of curcumin, capsaicin, and S-allylcysteine, which are major components found in commonly used dietary spice ingredients turmeric, chilli, and garlic, respectively. The DPPH assay demonstrates that these compounds readily scavenge free radicals. These compounds significantly curtail iron- (Fe2+) and quinolinic acid (QA)-induced lipid peroxidation and potently scavenge the superoxide anion generated by 1 mM cyanide in rat brain homogenate. The ferrozine assay was used to measure the extent of Fe2+ chelation, and electrochemistry was employed to measure the Fe3+ binding activity of curcumin, capsaicin, and S-allylcysteine. Both assays demonstrate that these compounds bind Fe2+ and Fe3+ and prevent the redox cycling of iron, suggesting that this may be an additional method through which these agents reduce Fe2+-induced lipid peroxidation. This study demonstrates the antioxidant and metal-binding properties of these spice ingredients, and it is hereby postulate that these compounds have important implications in the prevention or treatment of neurodegenerative diseases such as AD.

  14. Brain Development Parameters and Intelligence in Chilean High School Graduates

    Science.gov (United States)

    Ivanovic, Daniza M.; Leiva, Boris P.; Castro, Carmen G.; Olivares, Manuel G.; Jansana, Joan Manuel M.; Castro, Veronica G.; Almagia, Atilio Aldo F.; Toro, Triana D.; Urrutia, Maria Soledad C.; Miller, Patricio T.; Bosch, Enrique O.; Larrain, Cristian G.; Perez, Hernan T.

    2004-01-01

    The hypothesis that independently of sex, brain volume (BV) and head circumference (HC) are positively and significantly associated with intellectual quotient (IQ) was examined in a sample of 96 high school graduates of high [Wechsler Intelligence Scale for Adults--Revised (WAIS-R) is greater than 120] and low IQ (WAIS-R is less than 100) (1:1),…

  15. Defective iron-oxide nanoparticles synthesised by high temperature plasma processing: a magnetic characterisation versus temperature

    Science.gov (United States)

    Balasubramanian, C.; Joseph, B.; Orpe, PB; Saini, NL; Mukherjee, S.; Dziedzic-Kocurek, K.; Stanek, J.; Di Gioacchino, D.; Marcelli, A.

    2016-11-01

    Magnetic properties and phase compositions of iron-oxide nanoparticles synthesised by a high temperature arc plasma route have been investigated by Mössbauer spectroscopy and high harmonic magnetic AC susceptibility measurements, and correlated with morphological and structural properties for different synthesis conditions. The Mössbauer spectra precisely determined the presence of different iron-oxide fractions in the investigated nanoparticles, while the high harmonic magnetic susceptibility measurements revealed the occurrence of metastable magnetic phases evolving in temperature and time. This study illustrates magnetic properties and dynamics of the magnetic configurations of iron-oxide nanoparticles grown by high temperature plasma, a process less explored so far but extremely useful for synthesising large numbers of nanoparticles for industrial applications.

  16. Iron oxide nanoparticles stabilized inside highly ordered mesoporous silica

    Indian Academy of Sciences (India)

    A Bhaumik; S Samanta; N K Mal

    2005-11-01

    Nanosized iron oxide, a moderately large band-gap semiconductor and an essential component of optoelectrical and magnetic devices, has been prepared successfully inside the restricted internal pores of mesoporous silica material through in-situ reduction during impregnation. The samples were characterized by powder XRD, TEM, SEM/EDS, N2 adsorption, FT-IR and UV–visible spectroscopies. Characterization data indicated well-dispersed isolated nanoclusters of (Fe2O3),` within the internal surface of 2D-hexagonal mesoporous silica structure. No occluded Fe/Fe2O3 crystallites were observed at the external surface of the mesoporous silica nanocomposites. Inorganic mesoporous host, such as hydrophilic silica in the pore walls, directs a physical constraint necessary to prevent the creation of large Fe2O3 agglomerates and enables the formation of nanosized Fe2O3 particles inside the mesopore.

  17. A Powerful Mitochondria-Targeted Iron Chelator Affords High Photoprotection against Solar Ultraviolet A Radiation.

    Science.gov (United States)

    Reelfs, Olivier; Abbate, Vincenzo; Hider, Robert C; Pourzand, Charareh

    2016-08-01

    Mitochondria are the principal destination for labile iron, making these organelles particularly susceptible to oxidative damage on exposure to ultraviolet A (UVA, 320-400 nm), the oxidizing component of sunlight. The labile iron-mediated oxidative damage caused by UVA to mitochondria leads to necrotic cell death via adenosine triphosphate depletion. Therefore, targeted removal of mitochondrial labile iron via highly specific tools from these organelles may be an effective approach to protect the skin cells against the harmful effects of UVA. In this work, we designed a mitochondria-targeted hexadentate (tricatechol-based) iron chelator linked to mitochondria-homing SS-like peptides. The photoprotective potential of this compound against UVA-induced oxidative damage and cell death was evaluated in cultured primary skin fibroblasts. Our results show that this compound provides unprecedented protection against UVA-induced mitochondrial damage, adenosine triphosphate depletion, and the ensuing necrotic cell death in skin fibroblasts, and this effect is fully related to its potent iron-chelating property in the organelle. This mitochondria-targeted iron chelator has therefore promising potential for skin photoprotection against the deleterious effects of the UVA component of sunlight. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Synthesis of highly magnetic iron nanoparticles suitable for field-structuring using a b-diketone surfactant.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, James Ellis; Patel, Rina J.; Huber, Dale L.; Provencio, Paula Polyak; Venturini, Eugene Leo

    2003-06-01

    We describe the synthesis of highly magnetic iron nanoparticles using a novel surfactant, a {beta}-diketone. We have produced 6 nm iron nanoparticles with an unusually high saturation magnetization of more than 80% the value of bulk iron. Additionally, we measured a particle susceptibility of 14 (MKS units), which is far above the value possible for micron-scale spherical particles. These properties will allow for formation of composites that can be highly structured by magnetic fields.

  19. Brain inspired high performance electronics on flexible silicon

    KAUST Repository

    Sevilla, Galo T.

    2014-06-01

    Brain\\'s stunning speed, energy efficiency and massive parallelism makes it the role model for upcoming high performance computation systems. Although human brain components are a million times slower than state of the art silicon industry components [1], they can perform 1016 operations per second while consuming less power than an electrical light bulb. In order to perform the same amount of computation with today\\'s most advanced computers, the output of an entire power station would be needed. In that sense, to obtain brain like computation, ultra-fast devices with ultra-low power consumption will have to be integrated in extremely reduced areas, achievable only if brain folded structure is mimicked. Therefore, to allow brain-inspired computation, flexible and transparent platform will be needed to achieve foldable structures and their integration on asymmetric surfaces. In this work, we show a new method to fabricate 3D and planar FET architectures in flexible and semitransparent silicon fabric without comprising performance and maintaining cost/yield advantage offered by silicon-based electronics.

  20. Influence of Iron Supplementation on DMT1 (IRE)-induced Transport of Lead by Brain Barrier Systems in vivo

    Institute of Scientific and Technical Information of China (English)

    AN Dai Zhi; AI Jun Tao; FANG Hong Juan; SUN Ru Bao; SHI Yun; WANG Li Li; WANG Qiang

    2015-01-01

    Objective To investigate the potential involvement of DMT1 (IRE) protein in the brain vascular system in vivo during Pb exposure. Methods Three groups of male Sprague-Dawley rats were exposed to Pb in drinking water, among which two groups were concurrently administered by oral gavage once every other day as the low and high Fe treatment group, respectively, for 6 weeks. At the same time, the group only supplied with high Fe was also set as a reference. The animals were decapitated, then brain capillary-rich fraction was isolate from cerebral cortex. Western blot method was used to identify protein expression, and RT-PCR to detect the change of the mRNA. Results Pb exposure significantly increased Pb concentrations in cerebral cortex. Low Fe dose significantly reduced the cortex Pb levels, However, high Fe dose increased the cortex Pb levels. Interestingly, changes of DMT1 (IRE) protein in brain capillary-rich fraction were highly related to the Pb level, but those of DMT1 (IRE) mRNA were not significantly different. Moreover, the consistent changes in the levels of p-ERK1/2 or IRP1 with the changes in the levels of DMT1 (IRE). Conclusion These results suggest that Pb is transported into the brain through DMT1 (IRE), and the ERK MAPK pathway is involved in DMT1 (IRE)-mediated transport regulation in brain vascular system in vivo.

  1. Solubility Measurements and Modeling of Zinc, Lead and Iron Sulfides at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

    Solubility measurements of sulfides in aqueous solutions are necessary to understand the behaviour of these scaling minerals in geothermal and oil reservoirs. The low solubility levels of Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) make the solubility measurements a challenging...... task. Consequently existing data are rare and scattered. The aim of this work is to develop a reliable experimental procedure and to measure solubility of sulfides at high temperature and pressures. Additionally the experimental data are used for estimation of the solid-liquid equilibrium using...... oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP...

  2. The production and shelf life of high-iron, pre-cooked rice porridge with ferrous sulphate and other high-iron materials

    Directory of Open Access Journals (Sweden)

    Chowladda Teangpook

    2011-08-01

    Full Text Available The production and shelf life of high-iron, dried, pre-cooked rice porridge with ferrous sulphate and other high-iron materials was studied. Broken brown rice was soaked in water and ferrous sulphate was added at 0.05, 0.1 and 0.15% of the dried brown rice. The mixture was steamed for 20 min and dried in a double drum dryer. Green shallot, young ginger and cooked chicken fillet were dried in an electric cabinet dryer. Chicken blood and edible fern were dried in a double drum dryer and vacuum freezer respectively. The optimum ferrous sulphate added to the rice was 0.05% and the developed formulation of dried porridge consisted of ferrous sulphate rice (67.80%, chicken fillet (20%, chicken blood (3%, green shallot (0.7%, young ginger (1%, edible fern (0.5%, pepper powder (0.5%, sucrose (3%, salt (3% and monosodium glutamate (0.5%.The dried porridge had a high iron content of 10.18 mg/50 g and the shelf life was three months at room temperature when stored in either aluminum foil laminated bag or metalite bag.

  3. High voltage electric potentials to enhance brain-derived neurotrophic factor levels in the brain.

    Science.gov (United States)

    Yanamoto, Hiroji; Nakajo, Yukako; Kataoka, Hiroharu; Iihara, Koji

    2013-01-01

    Development of a safe method to increase brain-derived neurotrophic factor (BDNF) levels in the brain is expected to enhance learning and memory, induce tolerance to cerebral infarction or tolerance to depressive state, improve glucose metabolism, and suppress appetite and body weight. We have shown that repetitive applications of high-voltage electric potential (HELP) to the body increase BDNF levels in the brain, improving learning and memory in mice. Here, we investigated the effects of HELP treatment for a chronic period on the BDNF levels in the mouse brain, and on body weight in mice and humans. Adult mice were exposed to 3.1 or 5.4 kV HELP (on the body), 5 h a day for 24 weeks, and BDNF levels in the brain and alterations in body weight were analyzed. Humans [age, 53.2 ± 15.5 years old; BMI, 27.8 ± 5.6 (mean ± SD, n = 6)] were exposed to 3.9 kV HELP (on the body) for 1 h a day, continuing for 33 months (2.8 years) under the monitor of body weight. In mice, the HELP application elevated BDNF levels in the brain at least temporarily, affecting body weight in a voltage- and time-dependent manner. In humans, the HELP treatment reduced body weight compared to the pretreated initial values without any aversive effects (p BDNF, and 5.4 kV HELP was considered as excessive. HELP with an appropriate voltage can be utilized to increase BDNF levels in the brain for a prolonged period. We anticipate further investigations to clarify the effect of the optimal-leveled HELP therapy on memory disturbances, neurological deficits after stroke, depression, diabetes, obesity and metabolic syndrome.

  4. Highly dispersed iron species created on alkali-treated zeolite for ammonia SCR

    Institute of Scientific and Technical Information of China (English)

    Jing Ma; Duan Weng; Xiaodong Wu; Zhichun Si; Zhenwei Wu

    2013-01-01

    Alkaline treatment using sodium hydroxide was introduced to obtain a hierarchical pore structure in H-ZSM-5 zeolite. Fe-exchanged zeolite catalysts were prepared by impregnation on the original and alkali-treated zeolites, and were evaluated for NOx reduction by NH3, NO oxidation, and NH3 oxidation reactions. The highly dispersed iron species as active sites can be obtained by controlling the pore structure and particle size of zeolite. Therefore, the Fe/ZSM-5 catalyst treated mildly by sodium hydroxide before iron exchange, which contains amounts of highly dispersed Fe species, obtains over 80% NOx conversion at a wide temperature range of 250-500 1C.

  5. Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel-- A Comparison

    Institute of Scientific and Technical Information of China (English)

    Mehdi Mazar Atabaki; Sajjad Jafari; Hassan Abdollah-pour

    2012-01-01

    Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test.The wear test was carried out with different loads on a pin.Abrasive wear behavior of two alloys was evaluated by comparing mass loss,wear resistance,microhardness and friction coefficient.The microstructure of the specimens was detected using optical microscope.The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel.Due to the presence of M7C3 carbides on the high chromium cast iron matrix,impact crushers exhibited higher friction coefficient

  6. A High Rate Tension Device for Characterizing Brain Tissue

    CERN Document Server

    Rashid, Badar; Gilchrist, Michael; 10.1177/1754337112436900

    2013-01-01

    The mechanical characterization of brain tissue at high loading velocities is vital for understanding and modeling Traumatic Brain Injury (TBI). The most severe form of TBI is diffuse axonal injury (DAI) which involves damage to individual nerve cells (neurons). DAI in animals and humans occurs at strains > 10% and strain rates > 10/s. The mechanical properties of brain tissues at these strains and strain rates are of particular significance, as they can be used in finite element human head models to accurately predict brain injuries under different impact conditions. Existing conventional tensile testing machines can only achieve maximum loading velocities of 500 mm/min, whereas the Kolsky bar apparatus is more suitable for strain rates > 100/s. In this study, a custom-designed high rate tension device is developed and calibrated to estimate the mechanical properties of brain tissue in tension at strain rates < 90/s, while maintaining a uniform velocity. The range of strain can also be extended to 100% de...

  7. Regular Consumption of a High-Phytate Diet Reduces the Inhibitory Effect of Phytate on Nonheme-Iron Absorption in Women with Suboptimal Iron Stores.

    Science.gov (United States)

    Armah, Seth M; Boy, Erick; Chen, Dan; Candal, Priscila; Reddy, Manju B

    2015-08-01

    High phytate (HP) consumption is a concern in developing countries because of the high prevalence of iron deficiency in these countries. We investigated whether habitual consumption of an HP diet reduces the inhibitory effect of phytate on nonheme-iron absorption. Thirty-two nonanemic females, 18-35 y of age, with normal body mass index but with suboptimal iron stores (serum ferritin, ≤30 μg/L), were matched for serum ferritin concentration and randomly assigned to HP and low-phytate (LP) groups, in a parallel design study. Each subject consumed HP or LP foods with at least 2 of their daily meals for 8 wk, resulting in a change in phytate intake (from 718 to 1190 mg/d in the HP group and 623 to 385 mg/d in the LP group). The serum iron response over 4 h after a test meal containing 350 mg of phytate was measured at baseline and postintervention. Ferritin, transferrin receptor, and hepcidin concentrations were measured at baseline and 8 wk. Twenty-eight subjects completed the study (n = 14 per group). The serum iron response to the test meal increased in the HP group at postintervention, resulting in a 41% increase in the area under the curve (AUC; P serum iron response was lower (P serum iron response and hepcidin concentration, reflecting in a 64% lower AUC. We found that habitual consumption of an HP diet can reduce the negative effect of phytate on nonheme-iron absorption among young women with suboptimal iron stores. Future studies are needed to explore possible mechanisms. This trial was registered at clinicaltrials.gov as NCT02370940. © 2015 American Society for Nutrition.

  8. Ribbon scanning confocal for high-speed high-resolution volume imaging of brain.

    Science.gov (United States)

    Watson, Alan M; Rose, Annika H; Gibson, Gregory A; Gardner, Christina L; Sun, Chengqun; Reed, Douglas S; Lam, L K Metthew; St Croix, Claudette M; Strick, Peter L; Klimstra, William B; Watkins, Simon C

    2017-01-01

    Whole-brain imaging is becoming a fundamental means of experimental insight; however, achieving subcellular resolution imagery in a reasonable time window has not been possible. We describe the first application of multicolor ribbon scanning confocal methods to collect high-resolution volume images of chemically cleared brains. We demonstrate that ribbon scanning collects images over ten times faster than conventional high speed confocal systems but with equivalent spectral and spatial resolution. Further, using this technology, we reconstruct large volumes of mouse brain infected with encephalitic alphaviruses and demonstrate that regions of the brain with abundant viral replication were inaccessible to vascular perfusion. This reveals that the destruction or collapse of large regions of brain micro vasculature may contribute to the severe disease caused by Venezuelan equine encephalitis virus. Visualization of this fundamental impact of infection would not be possible without sampling at subcellular resolution within large brain volumes.

  9. Native iron

    DEFF Research Database (Denmark)

    Brooks, Charles Kent

    2015-01-01

    , a situation unique in the Solar System. In such a world, iron metal is unstable and, as we all know, oxidizes to the ferric iron compounds we call 'rust'. If we require iron metal it must be produced at high temperatures by reacting iron ore, usually a mixture of ferrous (Fe2+) and ferric (Fe3+) oxides (Fe2O3......, hematite, or FeO.Fe2O3, magnetite), with carbon in the form of coke. This is carried out in a blast furnace. Although the Earth's core consists of metallic iron, which may also be present in parts of the mantle, this is inaccessible to us, so we must make our own. In West Greenland, however, some almost...... unique examples of iron metal, otherwise called 'native iron' or 'telluric iron', occur naturally....

  10. Optimization of a phytase-containing micronutrient powder with low amounts of highly bioavailable iron for in-home fortification of complementary foods

    NARCIS (Netherlands)

    Troesch, B.; Egli, I.; Zeder, C.; Hurrell, R.F.; Pee, de S.; Zimmermann, M.B.

    2009-01-01

    Background: In-home fortification of complementary foods with micronutrient powders containing low amounts of iron may be potentially safer than powders containing high amounts of iron. However, low iron doses have little nutritional effect, unless iron absorption is high. Objective: The objective w

  11. Growth of diamond layers on diamond and cBN seeds using iron carbide under high pressure and high temperature

    CERN Document Server

    Li Xun; Hao Zhao Yin; LiuPeng; Li Musen; Zou Guang Tian; Cheng Shu Yu; Cheng Kai Jia

    2002-01-01

    Iron carbide without any graphite was studied under high pressure and high temperature (HPHT); diamond layers were obtained both on diamond and on cubic boron nitride seeds at 5.5 GPa and 1700-1750 K. The results showed that transition-metal carbide was the main intermediate in the course of the transformation from graphite to diamond under HPHT.

  12. THE INFLUENCE OF CHEMICAL COMPOSITION OF HIGH-CHROMIUM CAST IRONS ON THE MACHINABILITY

    Directory of Open Access Journals (Sweden)

    V. V. Netrebko

    2016-02-01

    Full Text Available Purpose. This research is aimed to obtain the regression dependence of the machinability on the chemical composition of pig iron (C, Cr, Mn and Ni in cast state. Methodology. The method of active experiment planning was used to build a mathematical model. Cast irons of composition 1.09…3.91 % С; 11.43…25.57 % Cr; 0.6…5.4 % Mn; 0.19…3.01 % Ni were studied. Cutting tools with plates 10х10 mm out of ВК8 according to State Standard 19051-80 were used for turning. Cutting modes: cutting depth – 0.8 mm, longitudinal feed – 0.15 mm/rot., spindle’s rotation frequency during turning – 200…360 rot./min. Lubricating and cooling liquids were not applied. Evaluation of iron workability was produced by determining the linear tool flank wear per unit length of the cutting path. Findings. Mathematically probabilistic equation of the regression dependence of the cutting tool’s wear on the C, Cr, Mn and Ni content in the machined cast iron were obtained. It was established that with the increase of Cr content in the cast iron to 14.8 % the cutting tool’s wear decreased as a result of formation of carbide eutectic which destroyed the doped ledeburite continuous frame. Further increase of chromium content promoted appearing of chromic carbides with high microhardness which considerably increased the tool’s wear. The conducted research shown that the minimum cutting tool’s wear 0,18 mkm/m was observed during the machining of cast iron containing: 1.09 % C, 14.8 % Cr, 2.3 % Mn and 1.2 % Ni; and the maximum wear is 48,96 mkm/m – when the content was: 3.91 % C, 11.43 % Cr, 5.4 % Mn and 0.19 % Ni. The tool’s wear reached 47.61 mkm/m during the treatment of cast iron containing 3.91 % C, 25.57 % Cr, 5.4 % Mn and 0.19 % Ni. Originality. Mathematically probabilistic model of the dependence of the cutting tool’s wear on the C, Cr, Mn and Ni content in the machined cast iron has been elaborated by the author. Practical value. The model

  13. Effect of high iron concentration enrichment on the phytoplankton in the Prydz Bay

    Institute of Scientific and Technical Information of China (English)

    张武昌; 孙松; 张永山; 扈传昱; 刘诚刚

    2004-01-01

    Shipboard iron enrichment phytoplankton incubations were carried out in the Prydz Bay, Antarctic, in January through to March 2002. Waters for the three incubations ( Exp 1,2 and 3 ) were collected from 20 m depth in three stations ( St. Ⅰ -1, Ⅶ-1 and Ⅶ-5 ), respectively. Although the nutrient concentrations in the surface waters of the three stations were consistently high, the Chl a concentrations varied considerably. Chl a concentrations in the 20 m depth of St. Ⅰ-1 and Ⅶ-1 werewas 2.35-2.65 for St. Ⅶ-5. There were six levels of enriched iron concentrations(control 5, 10, 20, 40 and 80 nM) in Exp 1 (6-29th, January) while three enriched iron levels (control 10 and 40 nM) were arranged in Exp 2 and 3 (both were from 20th February to 4 th March). The iron enrichments stimulated the phytoplankton growth and nutrient drawdown in Exp 1 and Exp 2. In Exp 3, phytoplankton growth and nutrient drawdown were at nearly the same rate in the control and iron enriched bottles. In Exp 1, Chl a concentrations in the bottles with 20, 40 and 80 nM iday, respectively, with a growth rate of 0.36-0.38 d-1. Chl a concentration in the day ( growth rate 0.27 d - 1 ). Phytoplankton growth rates in the control bottle and the bottle enriched with 5 nM iron were 0.13 and 0.16 d -1, respectively. In Exp 2, the Chl a growth rates were 0.13, 0.32 and 0.40 d-1 in the control bottle and bottles with 10 and 40 nM iron enrichments, respectively. It seems that 10 nM iron enrichment was not enough to stimulate the phytoplankton to reach their maximum growth rate. The result that the phytoplankton < 10 μm bloomed in Exp 1 and 2 was controversial to the "Ecumenical Iron Hypothesis" of Morel et al. ( 1991 ) that upon enrichment of iron, phytoplankton >10 μm would grow faster than phytoplankton<10 μm.

  14. Investigation on positive correlation of increased brain iron deposition with cognitive impairment in Alzheimer disease by using quantitative MR R2' mapping.

    Science.gov (United States)

    Qin, Yuanyuan; Zhu, Wenzhen; Zhan, Chuanjia; Zhao, Lingyun; Wang, Jianzhi; Tian, Qing; Wang, Wei

    2011-08-01

    Brain iron deposition has been proposed to play an important role in the pathophysiology of Alzheimer disease (AD). The aim of this study was to investigate the correlation of brain iron accumulation with the severity of cognitive impairment in patients with AD by using quantitative MR relaxation rate R2' measurements. Fifteen patients with AD, 15 age- and sex-matched healthy controls, and 30 healthy volunteers underwent 1.5T MR multi-echo T2 mapping and T2* mapping for the measurement of transverse relaxation rate R2' (R2'=R2*-R2). We statistically analyzed the R2' and iron concentrations of bilateral hippocampus (HP), parietal cortex (PC), frontal white matter (FWM), putamen (PU), caudate nucleus (CN), thalamus (TH), red nucleus (RN), substantia nigra (SN), and dentate nucleus (DN) of the cerebellum for the correlation with the severity of dementia. Two-tailed t-test, Student-Newman-Keuls test (ANOVA) and linear correlation test were used for statistical analysis. In 30 healthy volunteers, the R2' values of bilateral SN, RN, PU, CN, globus pallidus (GP), TH, and FWM were measured. The correlation with the postmortem iron concentration in normal adults was analyzed in order to establish a formula on the relationship between regional R2' and brain iron concentration. The iron concentration of regions of interest (ROI) in AD patients and controls was calculated by this formula and its correlation with the severity of AD was analyzed. Regional R2' was positively correlated with regional brain iron concentration in normal adults (r=0.977, PIron concentrations in bilateral HP, PC, PU, CN, and DN of patients with AD were significantly higher than those of the controls (Piron concentrations, especially in parietal cortex and hippocampus at the early stage of AD, were positively correlated with the severity of patients' cognitive impairment (Piron concentrations were, the more severe the cognitive impairment was. Regional R2' and iron concentration in parietal cortex and

  15. Low hepcidin levels in severely anemic malawian children with high incidence of infectious diseases and bone marrow iron deficiency.

    Science.gov (United States)

    Jonker, Femkje A M; Calis, Job C J; Phiri, Kamija; Kraaijenhagen, Rob J; Brabin, Bernard J; Faragher, Brian; Wiegerinck, Erwin T; Tjalsma, Harold; Swinkels, Dorine W; van Hensbroek, Michael Boele

    2013-01-01

    A reliable diagnostic biomarker of iron status is required for severely anemic children living in malarious areas because presumptive treatment with iron may increase their infection risk if they are not iron deficient. Current biomarkers are limited because they are altered by host inflammation. In this study hepcidin concentrations were assessed in severely anemic children living in a highly malarious area of Malawi and evaluated against bone marrow iron in order to determine the usefulness of hepcidin as a point of care test. 207 severely anemic children were assessed for levels of hepcidin, ferritin, serum transferrin receptor, erythropoietin, hematological indices, C-reactive protein, interleukin-6, malaria parasites and HIV infection. Deficiency of bone marrow iron stores was graded and erythroblast iron incorporation estimated. Interaction of covariates was assessed by structural-equation-modeling. Hepcidin was a poor predictor of bone marrow iron deficiency (sensitivity 66.7%; specificity 48.5%), and of iron incorporation (sensitivity 54.2%; specificity 61.8%), and therefore would have limitations as a point of care test in this category of children. As upregulation of hepcidin by inflammation and iron status was blunted by erythropoietin in this population, enhanced iron absorption through the low hepcidin values may increase infection risk. Current recommendations to treat all severely anemic children living in malarious areas with iron should therefore be reconsidered.

  16. Brain Network Analysis from High-Resolution EEG Signals

    Science.gov (United States)

    de Vico Fallani, Fabrizio; Babiloni, Fabio

    Over the last decade, there has been a growing interest in the detection of the functional connectivity in the brain from different neuroelectromagnetic and hemodynamic signals recorded by several neuro-imaging devices such as the functional Magnetic Resonance Imaging (fMRI) scanner, electroencephalography (EEG) and magnetoencephalography (MEG) apparatus. Many methods have been proposed and discussed in the literature with the aim of estimating the functional relationships among different cerebral structures. However, the necessity of an objective comprehension of the network composed by the functional links of different brain regions is assuming an essential role in the Neuroscience. Consequently, there is a wide interest in the development and validation of mathematical tools that are appropriate to spot significant features that could describe concisely the structure of the estimated cerebral networks. The extraction of salient characteristics from brain connectivity patterns is an open challenging topic, since often the estimated cerebral networks have a relative large size and complex structure. Recently, it was realized that the functional connectivity networks estimated from actual brain-imaging technologies (MEG, fMRI and EEG) can be analyzed by means of the graph theory. Since a graph is a mathematical representation of a network, which is essentially reduced to nodes and connections between them, the use of a theoretical graph approach seems relevant and useful as firstly demonstrated on a set of anatomical brain networks. In those studies, the authors have employed two characteristic measures, the average shortest path L and the clustering index C, to extract respectively the global and local properties of the network structure. They have found that anatomical brain networks exhibit many local connections (i.e. a high C) and few random long distance connections (i.e. a low L). These values identify a particular model that interpolate between a regular

  17. Perinatal iron deficiency and neurocognitive development

    Directory of Open Access Journals (Sweden)

    Emily Clare Radlowski

    2013-09-01

    Full Text Available Iron deficiency is the most common form of nutrient deficiency worldwide. It is highly prevalent due to the limited availability of high quality food in developing countries, and poor dietary habits in industrialized countries. According to the World Health Organization, it affects nearly 2 billion people and up to 50% of women who are pregnant. Maternal anemia during pregnancy is especially burdensome to healthy neurodevelopment in the fetus because iron is needed for proper neurogenesis, development, and myelination. Maternal anemia also increases the risk of low birth weight, either due to premature birth or fetal growth restriction, which is associated with delayed neurocognitive development and even psychiatric illness. As rapid neurodevelopment continues after birth infants that received sufficient iron in utero, but that receive a low iron diet after 6 months of age, also show deficits in neurocognitive development, including impairments in learning and memory. Unfortunately, the neurocognitive complications of iron deficiency during critical pre- and postnatal periods of brain development are difficult to remedy, persisting into adulthood. Thus, preventing iron deficiency in the pre- and postnatal periods is critical as is devising new means to recapture cognitive function in individuals who experienced early iron deficiency. This review will discuss the prevalence of pre- and postnatal iron deficiency, the mechanism, and effects of iron deficiency on brain and cognitive development.

  18. Iron-based superconductors: A new family to find the origin of high Tc superconductivity

    Institute of Scientific and Technical Information of China (English)

    Dao-xin Yao

    2011-01-01

    Since the discovery of iron-based superconductors in 2008 [1],a new tide of study on high Tc superconductors spreads worldwide quickly.After a few years' intensive study,many new compounds of iron-based superconductors have been found and their properties have been disclosed.The great achievement is attributed to the modern experimental techniques,fast developing numerical methods and improved theories during the study of cuprate superconductors or more generally strongly correlated electron systems.For instance,the Fermi surface,band structure and superconducting gap for a new compound could be measured quickly by modern ARPES technique [2].

  19. Rare twin linked to high-pressure phase transition in iron

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, L.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)], E-mail: lmdough@lanl.gov; Gray, G.T.; Cerreta, E.K.; McCabe, R.J.; Field, R.D.; Bingert, J.F. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2009-05-15

    At approximately 13 GPa, body-centered cubic alpha-iron undergoes a fully reversible, pressure-induced phase transition into hexagonal close-packed epsilon-iron. Microstructural evidence of this phase transition has been identified in the fully reverted alpha-iron as a large number of {l_brace}3 3 2{r_brace}<113> twins found primarily as secondary twins within {l_brace}1 1 2{r_brace}<111> primary twins. The {l_brace}3 3 2{r_brace}<113> twins were produced during high-pressure shock-loading of 1018 steel at a peak pressure above the alpha-epsilon phase transition pressure. The twins were identified using electron backscattered diffraction and transmission electron microscopy.

  20. Effects of structure and defect on fatigue limit in high strength ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hak; Kim, Min Gun [Kangwon National Univ., Chunchon (Korea, Republic of)

    2000-05-01

    In this paper, the influence of several factors such as hardness, internal defect and non-propagating crack on fatigue limits was investigated with three kinds of ductile iron specimens. From the experimental results the fatigue limits were examined in relation with hardness and tensile strength in case of high strength specimens under austempering treatment; in consequence the marked improvement of fatigue limits were not showed. The maximum defect size was an important factor to predict and to evaluate the fatigue limits of ductile irons. And, the quantitative relationship between the fatigue limits({sigma}{sub {omega}}) and the maximum defect size({radical}area{sub max}) was expressed as {sigma}{sub {omega}}{sup n} {center_dot} {radical}area{sub max}=C{sub 2}. Also, it was possible to explain the difference for the fatigue limits in three ductile irons by introduction of the non-propagating crack rates.

  1. Cracking behavior in a dissimilar weld between high silicon nodular cast iron and ferritic stainless steel

    Science.gov (United States)

    Kim, Sanghoon; Lee, Sangchul; Han, Kyutae; Hong, Seunggab; Lee, Changhee

    2010-06-01

    In this work, the microstructural evolution and cracking behavior of a dissimilar weld between high silicon nodular cast iron and ferritic stainless steel was investigated. An austenitic filler metal (Y309) was employed to produce the dissimilar weld. Microstructural analysis revealed that cracking formed at the unmixed zone (UMZ) and propagated into the partially melted zone (PMZ) in the bond line between the cast iron and the Y309, with hard layers formed around the bond line. The cracking behavior was strongly related to the difference in the melting points of cast iron and the Y309 filler metal, the local liquation of the laves phase, and the constitutional liquation between the graphite and austenite phases in the PMZ.

  2. CONTINUOUSLY-CYCLIC CASTING OF HOLLOW CYLINDER SLUGS OF HIGH-CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    E. I. Marukovich

    2009-01-01

    Full Text Available The analysis of castings formation is presented and the package of measures dircted on increase of stability of casting process is developed. Parametres of casting of hollow cylindrical billets by the method of directional solidification out of white high-chromium cast iron are defined.

  3. Influences of copper on solidification structure and hardening behavior of high chromium cast irons

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; XIONG Ji; FAN Hong-yuan; SHEN Bao-luo; GAO Sheng-ji

    2008-01-01

    The influences of copper on microstructure and the hardening behavior of high chromium cast irons subjected to sub-critical treatment were investigated.The results show that the mierostructure of the as-cast high chromium cast irons consists of retained austenite,martensite and M7 C3 type eutectic carbide.When copper is added into high chromium cast irons,austenite and carbide contents are increased.The increased addition of copper content from 0%to 1.84%leads to the increase of austenite and carbide from 15.9%and 20.0% to 61.0%and 35.5%,respectively.In the process of sub-critical treatment,the retained austenite in the matrix can be precipitated into secondary carbides and then transforms into martensite in cooling process,which causes the secondary hardening of the alloy under sub-critical treatment.High chromium cast irons containing copper in sub-critical treatment appear the second hardening curve peak due to the precipitation of copper from supersaturated matrix.

  4. Expression and Characterisation of Recombinant Rhodocyclus tenuis High Potential Iron-Sulphur Protein

    DEFF Research Database (Denmark)

    Caspersen, Michael Bjerg; Bennet, K.; Christensen, Hans Erik Mølager

    2000-01-01

    The high potential iron-sulfur protein (HiPIP) from Rhodocyclus tenuis strain 2761 has been overproduced in Escherichia coli from its structural gene, purified to apparent homogeneity, and then characterized by an array of methods. UV-visible spectra of the reduced and oxidized recombinant protein...

  5. A Micronutrient Powder with Low Doses of Highly Absorbable Iron and Zinc Reduces Iron and Zinc Deficiency and Improves Weight-For-Age Z-Scores in South African Children

    NARCIS (Netherlands)

    Troesch, B.; Stuijvenberg, van M.E.; Smuts, C.M.; Salome Kruger, H.; Biebinger, R.; Hurrell, R.F.; Baumgartner, J.; Zimmermann, M.B.

    2011-01-01

    Micronutrient powders (MNP) are often added to complementary foods high in inhibitors of iron and zinc absorption. Most MNP therefore include high amounts of iron and zinc, but it is no longer recommended in malarial areas to use untargeted MNP that contain the Reference Nutrient Intake for iron in

  6. A Micronutrient Powder with Low Doses of Highly Absorbable Iron and Zinc Reduces Iron and Zinc Deficiency and Improves Weight-For-Age Z-Scores in South African Children

    NARCIS (Netherlands)

    Troesch, B.; Stuijvenberg, van M.E.; Smuts, C.M.; Salome Kruger, H.; Biebinger, R.; Hurrell, R.F.; Baumgartner, J.; Zimmermann, M.B.

    2011-01-01

    Micronutrient powders (MNP) are often added to complementary foods high in inhibitors of iron and zinc absorption. Most MNP therefore include high amounts of iron and zinc, but it is no longer recommended in malarial areas to use untargeted MNP that contain the Reference Nutrient Intake for iron in

  7. Novel, high-activity hydroprocessing catalysts: Iron group phosphides

    Science.gov (United States)

    Wang, Xianqin

    A series of iron, cobalt and nickel transition metal phosphides was synthesized by means of temperature-programmed reduction (TPR) of the corresponding phosphates. The same materials, Fe2P, CoP and NO, were also prepared on a silica (SiO2) support. The phase purity of these catalysts was established by x-ray diffraction (XRD), and the surface properties were determined by N2 BET specific surface area (Sg) measurements and CO chemisorption. The activities of the silica-supported catalysts were tested in a three-phase trickle bed reactor for the simultaneous hydrodenitrogenation (HDN) of quinoline and hydrodesulfurization (HDS) of dibenzothiophene using a model liquid feed at realistic conditions (30 atm, 370°C). The reactivity studies showed that the nickel phosphide (Ni2P/SiO2) was the most active of the catalysts. Compared with a commercial Ni-Mo-S/gamma-Al 2O3 catalyst at the same conditions, Ni2P/silica had a substantially higher HDS activity (100% vs. 76%) and HDN activity (82% vs. 38%). Because of their good hydrotreating activity, an extensive study of the preparation of silica supported nickel phosphides, Ni2P/SiO 2, was carried out. The parameters investigated were the phosphorus content and the weight loading of the active phase. The most active composition was found to have a starting synthesis Ni/P ratio close to 1/2, and the best loading of this sample on silica was observed to be 18 wt.%. Extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge spectroscopy (XANES) measurements were employed to determine the structures of the supported samples. The main phase before and after reaction was found to be Ni2P, but some sulfur was found to be retained after reaction. A comprehensive scrutiny of the HDN reaction mechanism was also made over the Ni2P/SiO2 sample (Ni/P = 1/2) by comparing the HDN activity of a series of piperidine derivatives of different structure. It was found that piperidine adsorption involved an alpha-H activation

  8. Impact of iron powder pressing temperature on high-temperature corrosion of the obtained sinters

    Directory of Open Access Journals (Sweden)

    A. Jaroń

    2010-07-01

    Full Text Available The work presents the results of kinetic studies of the high-temperature oxidation process of metallic iron sinters obtained by a hotpressing method in an anaerobic atmosphere. The conducted studies for a model arrangement (iron allow to determine the effect of conditions for obtaining metallic pressed materials on the course of a high-temperature corrosion process. What is more, iron oxide sinters characterized by an expanded surface disclosed by a morphological analysis of the resulting scales may be used as catalyst carriers or as input material for obtaining porous iron by reduction. Sinters intended for research were obtained in a device for one-axial hot-pressing of samples at a pressure of 8 MPa within the temperature range 600 – 900oC in vacuum. The research into the kinetics of metallic sinters oxidation was carried out in the standard apparatus for high-temperature thermogravimetric studies using a continuous method with automatic recording of measurement within the temperature range 500 – 700oC in synthetic air atmosphere. The dependence of oxidation kinetics of metallic sinters on a pressing temperature was determined. Morphology as well as the chemical and phase composition of the tested samples were described using the SEM/EDX and XRD methods.

  9. Synthesis of high saturation magnetic iron oxide nanomaterials via low temperature hydrothermal method

    Science.gov (United States)

    Bhavani, P.; Rajababu, C. H.; Arif, M. D.; Reddy, I. Venkata Subba; Reddy, N. Ramamanohar

    2017-03-01

    Iron oxide nanoparticles (IONPs) were synthesized through a simple low temperature hydrothermal approach to obtain with high saturation magnetization properties. Two series of iron precursors (sulfates and chlorides) were used in synthesis process by varying the reaction temperature at a constant pH. The X-ray diffraction pattern indicates the inverse spinel structure of the synthesized IONPs. The Field emission scanning electron microscopy and high resolution transmission electron microscopy studies revealed that the particles prepared using iron sulfate were consisting a mixer of spherical (16-40 nm) and rod (diameter 20-25 nm, length distributed spherical shapes with size range 5-20 nm. On other hand, the IONPs synthesized at reaction temperature of 190 °C has spherical (16-46 nm) morphology in both series. The band gap values of IONPs were calculated from the obtained optical absorption spectra of the samples. The IONPs synthesized using iron sulfate at temperature of 130 °C exhibited high saturation magnetization (MS) of 103.017 emu/g and low remanant magnetization (Mr) of 0.22 emu/g with coercivity (Hc) of 70.9 Oe, which may be attributed to the smaller magnetic domains (dm) and dead magnetic layer thickness (t).

  10. Brain MR imaging in patients with hepatic cirrhosis: relationship between high intensity signal in basal ganglia on T{sub 1}-weighted images and elemental concentrations in brain

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, H. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Sato, M. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Yoshikawa, A. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Kimura, M. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Sonomura, T. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Terada, M. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan); Kishi, K. [Department of Radiology, Wakayama Medical College, 27-7, Wakayama City, 640 (Japan)

    1997-08-01

    In patients with hepatic cirrhosis, the globus pallidus and putamen show high intensity on T1-weighted MRI. While the causes of this high signal have been thought to include paramagnetic substances, especially manganese, no evidence for this has been presented. Autopsy in four cases of hepatic cirrhosis permitted measurement of metal concentrations in brain and histopathological examination. In three cases the globus pallidus showed high intensity on T1-weighted images. Mean manganese concentrations in globus pallidus, putamen and frontal white matter were 3.03 {+-} 0.38, 2.12 {+-} 0.37, and 1.38 {+-} 0.24 ({mu}g/g wet weight), respectively, being approximately four- to almost ten-fold the normal values. Copper concentrations in globus pallidus and putamen were also high, 50 % more than normal. Calcium, iron, zinc and magnesium concentrations were all normal. The fourth case showed no abnormal intensity in the basal ganglia and brain metal concentrations were all normal. Histopathologically, cases with showing high signal remarkable atrophy, necrosis, and deciduation of nerve cells and proliferation of glial cells and microglia in globus pallidus. These findings were similar to those in chronic manganese poisoning. On T1-weighted images, copper deposition shows no abnormal intensity. It is therefore inferred that deposition of highly concentrations of manganese may caused high signal on T1-weighted images and nerve cell death in the globus pallidus. (orig.). With 2 figs., 2 tabs.

  11. New cut-off values for ferritin and soluble transferrin receptor for the assessment of iron deficiency in children in a high infection pressure area

    NARCIS (Netherlands)

    K.S. Phiri; J.C.J. Calis; A. Siyasiya; I. Bates; B. Brabin; M. Boele van Hensbroek

    2009-01-01

    Background: Due to the potential risk of iron supplementation in iron replete children, it is important to properly identify children who may require iron supplementation. However, assessment of the iron status has proven to be difficult, especially in children living in areas with high infection pr

  12. New cut-off values for ferritin and soluble transferrin receptor for the assessment of iron deficiency in children in a high infection pressure area

    NARCIS (Netherlands)

    Phiri, K.S.; Calis, J.C.J.; Siyasiya, A.; Bates, I.; Brabin, B.; Boele van Hensbroek, M.

    2009-01-01

    Background: Due to the potential risk of iron supplementation in iron replete children, it is important to properly identify children who may require iron supplementation. However, assessment of the iron status has proven to be difficult, especially in children living in areas with high infection

  13. Brain catalase in the streptozotocin-rat model of sporadic Alzheimer's disease treated with the iron chelator-monoamine oxidase inhibitor, M30.

    Science.gov (United States)

    Sofic, E; Salkovic-Petrisic, M; Tahirovic, I; Sapcanin, A; Mandel, S; Youdim, M; Riederer, P

    2015-04-01

    Low intracerebroventricular (icv) doses of streptozotocin (STZ) produce regionally specific brain neurochemical changes in rats that are similar to those found in the brain of patients with sporadic Alzheimer's disease (sAD). Since oxidative stress is thought to be one of the major pathologic processes in sAD, catalase (CAT) activity was estimated in the regional brain tissue of animals treated intracerebroventricularly with STZ and the multitarget iron chelator, antioxidant and MAO-inhibitor M30 [5-(N-methyl-N-propargylaminomethyl)-8-hydroxyquinoline]. Five-day oral pre-treatment of adult male Wistar rats with 10 mg/kg/day M30 dose was followed by a single injection of STZ (1 mg/kg, icv). CAT activity was measured colorimetrically in the hippocampus (HPC), brain stem (BS) and cerebellum (CB) of the control, STZ-, M30- and STZ + M30-treated rats, respectively, 4 weeks after the STZ treatment. STZ-treated rats demonstrated significantly lower CAT activity in all three brain regions in comparison to the controls (p iron chelators such as M30 might also have beneficial effects in this non-transgenic sAD model.

  14. High Iron Requirement for Growth, Photosynthesis, and Low-light Acclimation in the Marine Cyanobacterium Synechococcus bacillaris

    Science.gov (United States)

    Sunda, W. G.; Huntsman, S. A.

    2016-02-01

    Iron is a critical nutrient in photosynthesis and limits phytoplankton growth in large regions of the ocean. Most of the iron in phytoplankton occurs in iron-containing proteins in the photosynthetic apparatus, and thus interactions among cellular iron, light, and growth rate are predicted. In agreement with this prediction, decreasing light intensity increased the cellular iron:carbon (Fe:C) ratio needed to support a given growth rate by 2- to 3-fold in both a coastal diatom Thalassiosira pseudonana, and a coastal cyanobacterium Synechococcus bacillaris due to an increase in iron-containing photosynthetic units. However, although the light responses were similar, the cellular Fe:C ratios needed to support a given growth rate were 5- to 8-fold higher in the cyanobacterium than in the diatom, a pattern seen in other Syechococcus isolates and eukaryotic phytoplankton. Due to the high iron requirement for growth and low light acclimation, we might expect Synechococcus to be at a competitive disadvantage in many low-iron and low-light environments. Indeed, it decreases rapidly with depth within the ocean's deep chlorophyll maximum (DCM), where iron and light levels are low and lower-iron requiring eukaryotic algae typically dominate the phytoplankton biomass in the mid to lower DCM.

  15. Parametric studies on iron-carbon composite nanoparticles synthesized by laser pyrolysis for increased passivation and high iron content

    Science.gov (United States)

    Dumitrache, F.; Morjan, I.; Fleaca, C.; Birjega, R.; Vasile, E.; Kuncser, V.; Alexandrescu, R.

    2011-04-01

    Iron/iron carbide core and carbon shell nanoparticles with improved magnetic properties were successfully synthesized by laser pyrolysis. As iron and carbon precursors, iron pentacarbonyl and pure or argon-diluted acetylene/ethylene mixtures, respectively, were used. The aim of the present optimization is the improvement of the magnetic properties of the nanomaterials by the increase of the iron percent in powders simultaneously to the maintaining of the protective character of the carbon coverage of nanoparticles. The chemical content and the crystalline structure were monitored by EDX, XRD and TEM techniques. In the first study, the content of acetylene as carbon source was diminished from 75% to 0%. Consequently the percent iron increased from 10 at.% to 28 at.% while oxygen remained relatively constant (around 5 at.%). In the second step, only diluted ethylene was used (maximum 87.5 vol.% Ar). In this case, an increase of iron to 46 at.% is observed. An optimum 50% carbon source dilution was found. Above this value, the carbon content increases and below it, superficial oxidation increases through the diminishing of the carbon shell. The magnetic properties and the Fe phase composition of the Fe-C samples were analyzed by temperature dependent Mössbauer spectroscopy.

  16. Removal of an iron matrix with polyoxyethylene-type surfactant-coated amberlite XAD-4 for the determination of trace impurities in high-purity iron.

    Science.gov (United States)

    Matsumiya, Hiroaki; Furuzawa, Shigeru; Hiraide, Masataka

    2005-08-15

    Admicellar sorbents for the removal of an iron matrix were prepared for the determination of trace impurities in high-purity iron. A 1.0-g amount of Amberlite XAD-4 (macroreticular styrene-divinylbenzene copolymer) was coated with 0.14-1.3 mmol of polyoxyethylene-type surfactants, including polyoxyethylene-4-tert-octylphenoxy ethers (Triton X series) and polyoxyethylene-4-isononylphenoxy ethers (PONPEs). The surfactant-coated XAD-4 was packed into a polypropylene column (7 mm i.d. x 50 mm high). A 5.0-cm(3) volume of sample solution was passed through the column at a flow rate of 0.5 cm(3) min(-1). Milligram amounts of iron(III) were effectively sorbed on the column from 8 mol dm(-3) hydrochloric acid solutions. Among the surfactants tested, polyoxyethylene(20)-4-isononylphenoxy ether (PONPE-20) showed the best performance: the iron leaked from the PONPE-20 column was 4 microg when 25 mg of iron(III) was introduced onto the column. Trace elements, such as Ti(IV), Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II), Pb(II), and Bi(III), were not retained on the column and thus quantitatively recovered in the column effluent. The effective separation of trace elements from an iron matrix allowed their accurate determinations by inductively coupled plasma-mass spectrometry or graphite furnace atomic absorption spectrometry. The detection limits (3sigma blank) were in the nanogram per gram range. The proposed method was successfully applied to the determination of trace impurities in high-purity iron samples.

  17. Iron source preference and regulation of iron uptake in Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Won Hee Jung

    2008-02-01

    Full Text Available The level of available iron in the mammalian host is extremely low, and pathogenic microbes must compete with host proteins such as transferrin for iron. Iron regulation of gene expression, including genes encoding iron uptake functions and virulence factors, is critical for the pathogenesis of the fungus Cryptococcus neoformans. In this study, we characterized the roles of the CFT1 and CFT2 genes that encode C. neoformans orthologs of the Saccharomyces cerevisiae high-affinity iron permease FTR1. Deletion of CFT1 reduced growth and iron uptake with ferric chloride and holo-transferrin as the in vitro iron sources, and the cft1 mutant was attenuated for virulence in a mouse model of infection. A reduction in the fungal burden in the brains of mice infected with the cft1 mutant was observed, thus suggesting a requirement for reductive iron acquisition during cryptococcal meningitis. CFT2 played no apparent role in iron acquisition but did influence virulence. The expression of both CFT1 and CFT2 was influenced by cAMP-dependent protein kinase, and the iron-regulatory transcription factor Cir1 positively regulated CFT1 and negatively regulated CFT2. Overall, these results indicate that C. neoformans utilizes iron sources within the host (e.g., holo-transferrin that require Cft1 and a reductive iron uptake system.

  18. Recovery of iron and calcium aluminate slag from high-ferrous bauxite by high-temperature reduction and smelting process

    Institute of Scientific and Technical Information of China (English)

    Ying-yi Zhang; Wei L; Yuan-hong Qi; Zong-shu Zou

    2016-01-01

    A high-temperature reduction and smelting process was used to recover iron and calcium aluminate slag from high-ferrous bauxite. The effects of w(CaO)/w(SiO2) ratio, anthracite ratio, and reduction temperature and time on the recovery and size of iron nuggets and on the Al2O3 grade of the calcium aluminate slag were investigated through thermodynamic calculations and experiments. The optimized process conditions were the bauxite/anthracite/slaked lime weight ratio of 100:16.17:59.37, reduction temperature of 1450°C and reduction time of 20 min. Under these conditions, high-quality iron nuggets and calcium aluminate slag were obtained. The largest size and the highest recov-ery rate of iron nuggets were 11.42 mm and 92.79wt%, respectively. The calcium aluminate slag mainly comprised Ca2SiO4 and Ca12Al14O33, with small amounts of FeAl2O4, CaAl2O4, and Ca2Al2SiO7.

  19. Monitoring of newborns at high risk for brain injury

    OpenAIRE

    Pisani, Francesco; Spagnoli, Carlotta

    2016-01-01

    Due to the increasing number of surviving preterm newborns and to the recognition of therapeutic hypothermia as the current gold standard in newborns with hypoxic-ischaemic encephalopathy, there has been a growing interest in the implementation of brain monitoring tools in newborns at high risk for neurological disorders. Among the most frequent neurological conditions and presentations in the neonatal period, neonatal seizures and neonatal status epilepticus, paroxysmal non-epileptic motor p...

  20. Analysis of thermal expansivity of iron (Fe) metal at ultra high temperature and pressure

    Indian Academy of Sciences (India)

    Deepika Kandpal; B R K Gupta

    2007-01-01

    In the present investigation we have explained the thermal and compression properties of HCP iron (Fe) at high pressure with variable temperature (isobars) and at high temperature with variable pressure (isotherm). The usual Tait equation of state is modified by incorporating the effect of thermal pressure. The calculated values of pressure for different isotherms and isochors and thermal expansivity () as a function of both temperature and pressure have been compared with those values obtained by Isaak et al and Wasserman et al.

  1. Chemical Synthesis of Highly Magnetic, Air-Stable Silica-Coated iron Particles

    Institute of Scientific and Technical Information of China (English)

    姜洪英; 钟伟; 汤怒江; 刘先松; 都有为

    2003-01-01

    Highly magnetic and air-stable silica-coated Fe particles have been prepared by a rapid and simple method. The specific magnetization of the sample can be as high as 201 Am2/kg even including silica, which is a non-magnetic material. The iron particle coated with silica is passivated and protected from oxidation. The influences of H2 reduction temperature on structure and magnetic properties are also studied.

  2. High-fat diet transition reduces brain DHA levels associated with altered brain plasticity and behaviour.

    Science.gov (United States)

    Sharma, Sandeep; Zhuang, Yumei; Gomez-Pinilla, Fernando

    2012-01-01

    To assess how the shift from a healthy diet rich in omega-3 fatty acids to a diet rich in saturated fatty acid affects the substrates for brain plasticity and function, we used pregnant rats fed with omega-3 supplemented diet from their 2nd day of gestation period as well as their male pups for 12 weeks. Afterwards, the animals were randomly assigned to either a group fed on the same diet or a group fed on a high-fat diet (HFD) rich in saturated fats for 3 weeks. We found that the HFD increased vulnerability for anxiety-like behavior, and that these modifications harmonized with changes in the anxiety-related NPY1 receptor and the reduced levels of BDNF, and its signalling receptor pTrkB, as well as the CREB protein. Brain DHA contents were significantly associated with the levels of anxiety-like behavior in these rats.

  3. Magnetoencephalography Detection of High-Frequency Oscillations in the Developing Brain

    Directory of Open Access Journals (Sweden)

    Kimberly eLeiken

    2014-12-01

    Full Text Available Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG methods. Twenty healthy children were studied with a high sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (> 1000 Hz in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the noninvasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

  4. Iron neurochemistry in Alzheimer's disease and Parkinson's disease: targets for therapeutics.

    Science.gov (United States)

    Belaidi, Abdel A; Bush, Ashley I

    2016-10-01

    Brain iron homeostasis is increasingly recognized as a potential target for the development of drug therapies for aging-related disorders. Dysregulation of iron metabolism associated with cellular damage and oxidative stress is reported as a common event in several neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases. Indeed, many proteins initially characterized in those diseases such as amyloid-β protein, α-synuclein, and huntingtin have been linked to iron neurochemistry. Iron plays a crucial role in maintaining normal physiological functions in the brain through its participation in many cellular functions such as mitochondrial respiration, myelin synthesis, and neurotransmitter synthesis and metabolism. However, excess iron is a potent source of oxidative damage through radical formation and because of the lack of a body-wide export system, a tight regulation of its uptake, transport and storage is crucial in fulfilling cellular functions while keeping its level below the toxicity threshold. In this review, we discuss the current knowledge on iron homeostasis in the brain and explore how alterations in brain iron metabolism affect neuronal function with emphasis on iron dysregulation in Alzheimer's and Parkinson's diseases. Finally, we discuss recent findings implicating iron as a diagnostic and therapeutic target for Alzheimer's and Parkinson's diseases. Iron plays a fundamental role in maintaining the high metabolic and energetic requirements of the brain. However, iron has to be maintained in a delicate balance as both iron overload and iron deficiency are detrimental to the brain and can trigger neurodegeneration. Here, we discuss the current knowledge on brain iron homeostasis and its involvement in major aging-related neurodegenerative diseases. This article is part of a special issue on Parkinson disease.

  5. Preparation of iron sulphides by high energy ball milling

    DEFF Research Database (Denmark)

    Lin, R.; Jiang, Jianzhong; Larsen, R.K.;

    1998-01-01

    The reaction of a powder mixture consisting of 50 a.% Fe and 50 a.% S during high energy ball milling has been studied by x-ray diffraction and Mossbauer spectroscopy. After around 19 h of milling FeS2 and FeS havebeen formed. By further milling the FeS compound becomes dominating and only Fe......S with an average crystallite size of about 10 nm was observed after milling times longer than 67 h. Mossbauer spectra obtained with applied fields show that the particles are antiferromagnetic or have a strongly canted spin structure....

  6. The effect of bonding environment on iron isotope fractionation between minerals at high temperature

    Science.gov (United States)

    Sossi, Paolo A.; O'Neill, Hugh St. C.

    2017-01-01

    Central to understanding the processes that drive stable isotope fractionation in nature is their quantification under controlled experimental conditions. The polyvalent element iron, given its abundance in terrestrial rocks, exerts controls on the structural and chemical properties of minerals and melts. The iron isotope compositions of typical high temperature minerals are, however, poorly constrained and their dependence on intensive (e.g. fO2) and extensive (e.g. compositional) variables is unknown. In this work, experiments involving a reference phase, 2 M FeCl2·4H2O(l), together with an oxide mix corresponding to the bulk composition of the chosen mineral were performed in a piston cylinder in Ag capsules. The oxide mix crystallised in situ at 1073 K and 1 GPa, in equilibrium with the iron chloride, and was held for 72 h. In order to characterise the effect of co-ordination and oxidation state on the isotope composition independently, exclusively Fe2+ minerals were substituted in: VIII-fold almandine, VI-fold ilmenite, fayalite and IV-fold chromite and hercynite. Δ57FeMin-FeCl2 increases in the order VIII ion. The composition of the VIFe2+-bearing minerals is similar to that of the aqueous FeCl2 fluid. To the degree that this represents the speciation of iron in fluids exsolving from magmas, the fractionation between them should be small, unless the iron is hosted in magnetite. By contrast, predominantly Fe2+-bearing mantle garnets should preserve a much lighter δ57Fe than their lower pressure spinel counterparts, a signature that may be reflected in partial melts from these lithologies. As the Fe-O bond lengths in fayalite and ilmenite are comparable, their isotope compositions overlap, suggesting that high Ti mare basalts acquired their heavy isotopic signature from ilmenite that crystallised late during lunar magma ocean solidification.

  7. Molecular dynamic simulations of iron (II) hydroxide in high temperature and supercritical water

    Science.gov (United States)

    Meng, Yuanliang

    In this study, the iron (II) hydroxide -- water system has been investigated at high temperatures by using molecular dynamics (MD) simulations. The simulation results reveal that at infinite dilution both Fe2+ cation and OH- anion have 6 water molecules within their first hydration shell and both types of ionic species experience a dramatic increase in their diffusion coefficients at near and supercritical conditions. The process of iron (II) hydroxide cluster formation has been simulated. The nano-clusters of larger sizes formed in supercritical water tend to be in an amorphous state. After having been quenched by an inert gas bath, iron (II) hydroxide nano-clusters with various structures have been produced. The geometries and associated binding energies of these species are given in detail. The vibrational spectra of iron (II) hydroxide clusters are also derived and compared with the spectrum of a bulk solid. The obtained results have a practical value for the analysis of potential corrosion products in supercritical water-cooled reactor (SCWR) which is employed in the new generation nuclear power plant design (GEN IV). This work also illustrates the process of hydrothermal synthesis of oxide nano-particles.

  8. Magnetic iron particles with high magnetization useful for immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Tokoro, Hisato [Hitachi Metals, Ltd., Advanced Electronics Research Laboratory, 5200 Mikajiri, Kumagaya, Saitama 360-0843 (Japan)], E-mail: hisato_tokoro@hitachi-metals.co.jp; Nakabayashi, Takashi; Fujii, Shigeo [Hitachi Metals, Ltd., Advanced Electronics Research Laboratory, 5200 Mikajiri, Kumagaya, Saitama 360-0843 (Japan); Zhao Hong; Haefeli, Urs O. [Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, BC V6T 1Z3 (Canada)

    2009-05-15

    TiO{sub 2}-encapsulated metallic Fe particles (Ti-O/Fe) were synthesized through a solid phase reaction. The Ti-O/Fe particles were non-toxic to tumor cells in a cell viability assay. After silica coating using a sol-gel method, streptavidin was covalently bound onto the Ti-O/Fe particles. Thus produced HMMI particles showed higher magnetization (114 Am{sup 2}/kg) and a larger specific surface area (15 m{sup 2}/g) than conventional streptavidin-immobilized magnetite particles. The high magnetization allowed for rapid magnetic separation, while the additional large specific surface area improved the detection of the adiponectin antigen both in terms of extended detection range and higher assay speed.

  9. High-resolution digital brain atlases: a Hubble telescope for the brain.

    Science.gov (United States)

    Jones, Edward G; Stone, James M; Karten, Harvey J

    2011-05-01

    We describe implementation of a method for digitizing at microscopic resolution brain tissue sections containing normal and experimental data and for making the content readily accessible online. Web-accessible brain atlases and virtual microscopes for online examination can be developed using existing computer and internet technologies. Resulting databases, made up of hierarchically organized, multiresolution images, enable rapid, seamless navigation through the vast image datasets generated by high-resolution scanning. Tools for visualization and annotation of virtual microscope slides enable remote and universal data sharing. Interactive visualization of a complete series of brain sections digitized at subneuronal levels of resolution offers fine grain and large-scale localization and quantification of many aspects of neural organization and structure. The method is straightforward and replicable; it can increase accessibility and facilitate sharing of neuroanatomical data. It provides an opportunity for capturing and preserving irreplaceable, archival neurohistological collections and making them available to all scientists in perpetuity, if resources could be obtained from hitherto uninterested agencies of scientific support. © 2011 New York Academy of Sciences.

  10. High-pressure Moessbauer study of perovskite iron oxides

    CERN Document Server

    Kawakami, T; Sasaki, T; Kuzushita, K; Morimoto, S; Endo, S; Kawasaki, S; Takano, M

    2002-01-01

    The perovskite oxides CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 have been investigated by high-pressure sup 5 sup 7 Fe Moessbauer spectroscopy. The critical temperatures of the charge disproportionation (CD) and the magnetic order (MO) have been determined as a function of pressure. In CaFeO sub 3 the CD (2Fe sup 4 sup + -> Fe sup 3 sup + + Fe sup 5 sup +) occurs at an almost constant temperature of 290 K in the pressure range of 0-17 GPa. Above 20 GPa, the CD is suppressed. The MO temperature of 125 K at an ambient pressure rises to 300 K at 34 GPa. In La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 FeO sub 3 the CD (3Fe sup 1 sup 1 sup / sup 3 sup + -> 2Fe sup 3 sup + + Fe sup 5 sup +) and the MO occur at the same temperature up to 21 GPa, which decreases from 207 to 165 K with increasing pressure. Above 25 GPa, however, the MO temperature rises above 400 K.

  11. The Bacillus subtilis EfeUOB transporter is essential for high-affinity acquisition of ferrous and ferric iron.

    Science.gov (United States)

    Miethke, Marcus; Monteferrante, Carmine G; Marahiel, Mohamed A; van Dijl, Jan Maarten

    2013-10-01

    Efficient uptake of iron is of critical importance for growth and viability of microbial cells. Nevertheless, several mechanisms for iron uptake are not yet clearly defined. Here we report that the widely conserved transporter EfeUOB employs an unprecedented dual-mode mechanism for acquisition of ferrous (Fe[II]) and ferric (Fe[III]) iron in the bacterium Bacillus subtilis. We show that the binding protein EfeO and the permease EfeU form a minimal complex for ferric iron uptake. The third component EfeB is a hemoprotein that oxidizes ferrous iron to ferric iron for uptake by EfeUO. Accordingly, EfeB promotes growth under microaerobic conditions where ferrous iron is more abundant. Notably, EfeB also fulfills a vital role in cell envelope stress protection by eliminating reactive oxygen species that accumulate in the presence of ferrous iron. In conclusion, the EfeUOB system contributes to the high-affinity uptake of iron that is available in two different oxidation states. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Effect of heat treatment on microstructure and mechanical properties of high boron white cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xiang, E-mail: xchen@mail.tsinghua.edu.cn [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Li Yanxiang [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)

    2010-12-15

    Research highlights: {yields} The iron comprises a fine pearlite and M{sub 2}B boride at as-cast condition. {yields} Tempered at a higher temperature, some particles precipitated in the matrix. {yields} The secondary precipitates have a crystal structure of M{sub 23}(B,C){sub 6}. {yields} Optimum structure is obtained when tempered at 400 deg. C. - Abstract: The effect of different tempering temperatures on the microstructure and mechanical properties of high boron white cast iron after air quenching was studied. The experimental results indicate that the high boron white cast iron comprises a dendritic matrix and interdendritic boride M{sub 2}B that distributed in the form of continuous network and the matrix is composed of fine pearlite at as-cast condition. After austenitising at 920 deg. C and air quenching, the matrix of high boron cast iron is changed from pearlite to lath-type martensite, and the morphology of boride is still kept in the form of continuous network. After tempered at 200 deg. C or a higher temperature, a secondary precipitation with a size of tens of nanometers is found in the matrix, and the size and the amount of this secondary precipitation increase with the increasing of tempering temperature. TEM analysis shows that the secondary precipitates have a crystal structure of M{sub 23}(B,C){sub 6}. With the increasing of tempering temperature after air quenching, the hardness decreases, and the impact toughness firstly increases to a maximum value and then decreases. The optimum structure that has a combination of high hardness and high impact toughness can be obtained when the tempering temperature is lower than 400 deg. C.

  13. Optimizing brain tumor resection. High-field interventional MR imaging.

    Science.gov (United States)

    Tummala, R P; Chu, R M; Liu, H; Truwit, C L; Hall, W A

    2001-11-01

    High-field strength iMRI guidance is an effective tool for brain tumor resection. Although its use lengthens the average time for a craniotomy, the reward is a more extensive tumor excision compared with conventional neurosurgery without an increased risk to the patient (Table 4). Although intraoperative patient transfer into and out of the magnet is cumbersome, the possibility for complete resection, especially for a low-grade glioma, makes the effort worthwhile. The cost and technical support required for this system presently limits its use to only a few sites worldwide. As with any technology, further refinements will make this system less expensive and more attainable. Practical consideration aside, high-field strength iMRI is presently [table: see text] the most effective tool available for brain tumor resection. Because of its novelty, future studies are necessary to determine if this technology lowers the incidence of and extends the duration to tumor recurrence as the preliminary data in children suggests. These are the ultimate measures of efficacy for any brain tumor treatment. Based on the rapid advancement of technology, will today's high-field strength interventional magnet become tomorrow's low-field system? Very high-field strength designs may improve diagnostic capabilities through higher resolution, but their interventional applications may be hindered by increased sensitivity for clinically insignificant abnormalities and decreased specificity for clinically relevant lesions. As new technology is developed, clinicians must continue to explore and refine the existing high-field strength iMRI to make it cost-effective and widely applicable.

  14. Targeting Cells With MR Imaging Probes: Cellular Interaction And Intracellular Magnetic Iron Oxide Nanoparticles Uptake In Brain Capillary Endothelial and Choroidal Plexus Epithelial Cells

    Science.gov (United States)

    Cambianica, I.; Bossi, M.; Gasco, P.; Gonzalez, W.; Idee, J. M.; Miserocchi, G.; Rigolio, R.; Chanana, M.; Morjan, I.; Wang, D.; Sancini, G.

    2010-10-01

    Magnetic iron oxide nanoparticles (NPs) are considered for various diagnostic and therapeutic applications in brain including their use as contrast agent for magnetic resonance imaging. In delivery application, the critical step is the transport across cell layers and the internalization of NPs into specific cells, a process often limited by poor targeting specificity and low internalization efficiency. The development of the models of brain endothelial cells and choroidal plexus epithelial cells in culture has allowed us to investigate into these mechanisms. Our strategy is aimed at exploring different routes to the entrapment of iron oxide NPs in these brain related cells. Here we demonstrated that not only cells endowed with a good phagocytic activity like activated macrophages but also endothelial brain capillary and choroidal plexus epithelial cells do internalize iron oxide NPs. Our study of the intracellular trafficking of NPs by TEM, and confocal microscopy revealed that NPs are mainly internalized by the endocytic pathway. Iron oxide NPs were dispersed in water and coated with 3,4-dihydroxyl-L-phenylalanine (L-DOPA) using standard procedures. Magnetic lipid NPs were prepared by NANOVECTOR: water in oil in water (W/O/W) microemulsion process has been applied to directly coat different iron based NPs by lipid layer or to encapsulate them into Solid Lipid Nanoparticles (SLNs). By these coating/loading the colloidal stability was improved without strong alteration of the particle size distribution. Magnetic lipid NPs could be reconstituted after freeze drying without appreciable changes in stability. L-DOPA coated NPs are stable in PBS and in MEM (Modified Eagle Medium) medium. The magnetic properties of these NPs were not altered by the coating processes. We investigated the cellular uptake, cytotoxicity, and interaction of these NPs with rat brain capillary endothelial (REB4) and choroidal plexus epithelial (Z310) cells. By means of widefield, confocal

  15. Doping dependence of spin excitations and its correlations with high-temperature superconductivity in iron pnictides.

    Science.gov (United States)

    Wang, Meng; Zhang, Chenglin; Lu, Xingye; Tan, Guotai; Luo, Huiqian; Song, Yu; Wang, Miaoyin; Zhang, Xiaotian; Goremychkin, E A; Perring, T G; Maier, T A; Yin, Zhiping; Haule, Kristjan; Kotliar, Gabriel; Dai, Pengcheng

    2013-01-01

    High-temperature superconductivity in iron pnictides occurs when electrons and holes are doped into their antiferromagnetic parent compounds. Since spin excitations may be responsible for electron pairing and superconductivity, it is important to determine their electron/hole-doping evolution and connection with superconductivity. Here we use inelastic neutron scattering to show that while electron doping to the antiferromagnetic BaFe₂As₂ parent compound modifies the low-energy spin excitations and their correlation with superconductivity (100 meV), hole-doping suppresses the high-energy spin excitations and shifts the magnetic spectral weight to low-energies. In addition, our absolute spin susceptibility measurements for the optimally hole-doped iron pnictide reveal that the change in magnetic exchange energy below and above T(c) can account for the superconducting condensation energy. These results suggest that high-T(c) superconductivity in iron pnictides is associated with both the presence of high-energy spin excitations and a coupling between low-energy spin excitations and itinerant electrons.

  16. Analysis of high iron rice lines reveals new miRNAs that target iron transporters in roots

    Science.gov (United States)

    Paul, Soumitra; Gayen, Dipak; Datta, Swapan K.; Datta, Karabi

    2016-01-01

    The present study highlights the molecular regulation of iron transport in soyFER1-overexpressing transgenic rice. Accumulation of iron in three different seed developmental stages, milk, dough, and mature, has been examined. The transgenic seeds of the milk stage showed significant augmentation of iron and zinc levels compared with wild-type seeds, and similar results were observed throughout the dough and mature stages. To investigate the regulation of iron transport, the role of miRNAs was studied in roots of transgenic rice. Sequencing of small RNA libraries revealed 153 known and 41 novel miRNAs in roots. Among them, 59 known and 14 novel miRNAs were found to be significantly expressed. miR166, miR399, and miR408 were identified as playing a vital role in iron uptake in roots of transgenic plants . Most importantly, four putative novel miRNAs, namely miR11, miR26, miR30, and miR31, were found to be down-regulated in roots of transgenic plants. For all these four novel miRNAs, natural resistance-associated macrophage protein 4 (NRAMP4), encoding a metal transporter, was predicted as a target gene. It is hypothesized that the NRAMP4 transporter is activated in roots of transgenic plants due to the lower abundance of its corresponding putative novel miRNAs. The relative transcript level of the NRAMP4 transcript was increased from 0.107 in the wild type to 65.24 and 55.39 in transgenic plants, which demonstrates the elevated amount of iron transport in transgenic plants. In addition, up-regulation of OsYSL15, OsFRO2, and OsIRT1 in roots also facilitates iron loading in transgenic seeds. PMID:27729476

  17. High iron sequestrating bifidobacteria inhibit enteropathogen growth and adhesion to intestinal epithelial cells in vitro

    Directory of Open Access Journals (Sweden)

    Pamela Vazquez-Gutierrez

    2016-09-01

    Full Text Available The gut microbiota plays an important role in host health, in particular by its barrier effect and competition with exogenous pathogenic bacteria. In the present study, the competition of Bifidobacterium pseudolongum PV8-2 (Bp PV8-2 and Bifidobacterium kashiwanohense PV20-2 (Bk PV20-2, isolated from anemic infant gut microbiota and selected for their high iron sequestration properties was investigated against Salmonella Typhimurium (S. Typhi and Escherichia coli O157:H45 (EHEC by using co-culture tests and assays with intestinal cell lines. Single and co-cultures were carried out anaerobically in chemically semi-defined low iron (1.5 µM Fe medium (CSDLIM without and with added ferrous iron (30 µM Fe. Surface properties of the tested strains were measured by bacterial adhesion to solvent xylene, chloroform, ethyl acetate, and to extracellular matrix molecules, mucus II, collagen I, fibrinogen, fibronectin. HT29-MTX mucus-secreting intestinal cell cultures were used to study bifidobacteria competition, inhibition and displacement of the enteropatogens. During co-cultures in CSDLIM we observed strain-dependent inhibition of bifidobacterial strains on enteropathogens, independent of pH, organic acid production and supplemented iron. Bp PV8-2 significantly (P<0.05 inhibited S. Typhi N15 and EHEC after 24 h compared to single culture growth. In contrast Bk PV20-2 showed less inhibition on S. Typhi N15 than Bp PV8-2, and no inhibition on EHEC. Affinity for intestinal cell surface glycoproteins was strain-specific, with high affinity of Bp PV8-2 for mucin and Bk PV20-2 for fibronectin. Bk PV20-2 showed high adhesion potential (15.6 +/- 6.0 % to HT29-MTX cell layer compared to Bp PV8-2 (1.4 +/- 0.4 %. In competition, inhibition and displacement tests, Bp PV8-2 significantly (P<0.05 reduced S. Typhi N15 and EHEC adhesion, while Bk PV20-2 was only active on S. Typhi N15 adhesion. To conclude, bifidobacterial strains selected for their high iron binding

  18. Li4FeH6: Iron-containing complex hydride with high gravimetric hydrogen density

    Directory of Open Access Journals (Sweden)

    Hiroyuki Saitoh

    2014-07-01

    Full Text Available Li4FeH6, which has the highest gravimetric hydrogen density of iron-containing complex hydrides reported so far, is synthesized by hydrogenation of a powder mixture of iron and LiH above 6.1 GPa at 900 °C. In situ synchrotron radiation X-ray diffraction measurements reveal that while kinetics require high temperature and thus high pressure for the synthesis, Li4FeH6 is expected to be thermodynamically stable slightly below room temperature at ambient pressure; further synthetic studies to suppress the kinetic effects may enable us to synthesize Li4FeH6 at moderate pressures. Li4FeH6 can be recovered at ambient conditions where Li4FeH6 is metastable.

  19. Phase diagram calculation of high chromium cast irons and influence of its chemical composition

    Energy Technology Data Exchange (ETDEWEB)

    Li Da; Liu Ligang; Zhang Yunkun; Ye Chunlei [National Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Ren Xuejun [School of Engineering, Liverpool John Moores University, Liverpool L3 3AF (United Kingdom); Yang Yulin [National Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Yang Qingxiang [National Key Laboratory of Metastable Materials Science and Technology, College of Material Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)], E-mail: qxyang@ysu.edu.cn

    2009-02-15

    The phase transformation and the carbide precipitation temperatures of the high chromium cast iron with Cr content of 15% were measured by using differential scanning calorimetry (DSC). The matrix and the type of carbides of the specimen after quenching were determined by using X-ray diffraction (XRD) in this work. Meanwhile, the shape and the number of carbides in the different specimens were detected by using optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The equilibrium phase of this high chromium cast iron was calculated by using Thermo-Calc software based on above experiments. The calculation results obtained from Thermo-Calc software is agreed with the ones from experiments. The work provides a practical method for engineers and researchers in related areas.

  20. High temperature oxidation behavior of ODS iron-base alloys for nuclear energy application

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.; Zhou, Z.; Liao, L.; Chen, W.; Ge, C. [Univ. of Science and Technology Beijing, School of Materials Science and Engineering, Beijing (China)

    2010-07-01

    Oxide dispersion strengthened (ODS) iron based alloys are considered as promising high temperature structural material for advanced nuclear energy systems due to its higher creep strength and radiation damage resistance than conventional commercial steels. In this study, the oxidation behavior of ODS iron based alloys with different Cr content (12-18%) was investigated by exposing samples at high temperature of 700℃ and 1000℃ in atmosphere environment, the exposure time is up to 500 h. Results showed that 14Cr and 18Cr ODS alloys exhibited better oxidation resistance than 12Cr ODS alloys. For the same chromium content, the oxidation resistance of ODS alloys are better than that of non-ODS alloys. (author)

  1. High Tolerance to Iron Contamination in Lead Halide Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Poindexter, Jeremy R. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Hoye, Robert L. Z. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Nienhaus, Lea [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Kurchin, Rachel C. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Morishige, Ashley E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Looney, Erin E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Osherov, Anna [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Correa-Baena, Juan-Pablo [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Lai, Barry [Advanced; Bulović, Vladimir [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Stevanović, Vladan [Colorado School of Mines, 1500; National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Bawendi, Moungi G. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Buonassisi, Tonio [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States

    2017-07-05

    The relationship between charge-carrier lifetime and the tolerance of lead halide perovskite (LHP) solar cells to intrinsic point defects has drawn much attention by helping to explain rapid improvements in device efficiencies. However, little is known about how charge-carrier lifetime and solar cell performance in LHPs are affected by extrinsic defects (i.e., impurities), including those that are common in manufacturing environments and known to introduce deep levels in other semiconductors. Here, we evaluate the tolerance of LHP solar cells to iron introduced via intentional contamination of the feedstock and examine the root causes of the resulting efficiency losses. We find that comparable efficiency losses occur in LHPs at feedstock iron concentrations approximately 100 times higher than those in p-type silicon devices. Photoluminescence measurements correlate iron concentration with nonradiative recombination, which we attribute to the presence of deep-level iron interstitials, as calculated from first-principles, as well as iron-rich particles detected by synchrotron-based X-ray fluorescence microscopy. At moderate contamination levels, we witness prominent recovery of device efficiencies to near-baseline values after biasing at 1.4 V for 60 s in the dark. We theorize that this temporary effect arises from improved charge-carrier collection enhanced by electric fields strengthened from ion migration toward interfaces. Our results demonstrate that extrinsic defect tolerance contributes to high efficiencies in LHP solar cells, which inspires further investigation into potential large-scale manufacturing cost savings as well as the degree of overlap between intrinsic and extrinsic defect tolerance in LHPs and 'perovskite-inspired' lead-free stable alternatives.

  2. In-situ Phase Transformation and Deformation of Iron at High Pressure andTemperature

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Lowell; Kunz, Martin; Knight, Jason; Nasiatka, James; Voltolini, Marco; Wenk, Hans-Rudolf

    2008-07-01

    With a membrane based mechanism to allow for pressure change of a sample in aradial diffraction diamond anvil cell (rDAC) and simultaneous infra-red laser heating, itis now possible to investigate texture changes during deformation and phasetransformations over a wide range of temperature-pressure conditions. The device isused to study bcc (alpha), fcc (gamma) and hcp (epislon) iron. In bcc iron, room temperature compression generates a texture characterized by (100) and (111) poles parallel to the compression direction. During the deformation induced phase transformation to hcp iron, a subset of orientations are favored to transform to the hcp structure first and generate a texture of (01-10) at high angles to the compression direction. Upon further deformation, the remaining grains transform, resulting in a texture that obeys the Burgers relationship of (110)bcc // (0001)hcp. This is in contrast to high temperature results that indicate that texture is developed through dominant pyramidal {2-1-12}<2-1-13> and basal (0001)-{2-1-10} slip based on polycrystal plasticity modeling. We also observe that the high temperature fcc phase develops a 110 texture typical for fcc metals deformed in compression.

  3. Corrosion of high-level radioactive waste iron-canisters in contact with bentonite.

    Science.gov (United States)

    Kaufhold, Stephan; Hassel, Achim Walter; Sanders, Daniel; Dohrmann, Reiner

    2015-03-21

    Several countries favor the encapsulation of high-level radioactive waste (HLRW) in iron or steel canisters surrounded by highly compacted bentonite. In the present study the corrosion of iron in contact with different bentonites was investigated. The corrosion product was a 1:1 Fe layer silicate already described in literature (sometimes referred to as berthierine). Seven exposition test series (60 °C, 5 months) showed slightly less corrosion for the Na-bentonites compared to the Ca-bentonites. Two independent exposition tests with iron pellets and 38 different bentonites clearly proved the role of the layer charge density of the swelling clay minerals (smectites). Bentonites with high charged smectites are less corrosive than bentonites dominated by low charged ones. The type of counterion is additionally important because it determines the density of the gel and hence the solid/liquid ratio at the contact to the canister. The present study proves that the integrity of the multibarrier-system is seriously affected by the choice of the bentonite buffer encasing the metal canisters in most of the concepts. In some tests the formation of a patina was observed consisting of Fe-silicate. Up to now it is not clear why and how the patina formed. It, however, may be relevant as a corrosion inhibitor. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. [Restless legs syndrome in patients with high serum ferritin and normal iron levels].

    Science.gov (United States)

    Peraita-Adrados, Rosa; Duque-Ramírez, Luis G; Vela-Bueno, Antonio

    2011-10-01

    To document the association between restless legs syndrome (RLS) and high ferritin levels in five patients. The five patients were male, mean age: 59 years (range: 36-73 years). The patients were referred for RLS (two of them blood donors), in two cases associated with obstructive sleep apnea. Patients underwent a video-PSG recording. Serum iron and serum ferritin were determined. All patients fulfilled the clinical criteria for RLS: leg paresthesias associated with an urge to move, motor restless-ness, worsening of symptoms during the evening and night, and partial relief with activity, difficulty falling asleep, and presence of nocturnal awakenings due to RLS. Neurological examination, EEGs, EMGs and MRIs were normal. Video-PSGs recordings showed a disturbed and fragmented sleep with a reduction in total sleep time, low sleep efficiency, respiratory abnormalities with an apnea-hipopnea index > 10/h in two cases, and in all of them a periodic leg movements index > 5/h. The serum iron levels were within the normal range in all cases, whereas those in serum ferritin levels were high. To our knowledge the association of normal serum iron with high serum ferritin levels in patients diagnosed clinically and polygraphically as having RLS with periodic leg movements has not been described before. The notion of an involvement of a dopaminergic mechanism in the pathophysiology of RLS is supported by the decrease in the values of serum ferritin concentration observed in one patient during follow-up while being treated with dopaminergic agents.

  5. Evaluation and Application of Two High-Iron Transgenic Rice Lines Expressing a Pea Ferritin Gene

    Institute of Scientific and Technical Information of China (English)

    YE Hong-xai; LI Mei; Guo Ze-jian; Shu Qing-yao; xu Xiao-hui; BAO Jin-song; SHEN Sheng-quan

    2008-01-01

    A totaI of 105 transgenic rice lines independently transformed with a pea ferritin gene (Fer)were previously obtained.After seven generations of selfing and β-glucuronidase(GUS)assisted selection,82 transgenic lines with stable agronomic traits were got.Among the 82 transgenic lines,two high-iron transgenic rice lines Fer34 and Fer65,with the iron contents in the milled rice being 4.82 and 3.46 times of that of the wild type Xiushui 11,respectively were identified.In the two transgenic lines,the exogenous Fer gene was highly expressed,and inherited as a single locus.The transgene had no negative effect on the agronomic traits of rice plant,other mineral nutritional components,appearance quailty and eating quailty of the milled rice,indicating that these two lines were elite high-iron breeding lines.Furthermore,the practical application and further studies facilitating utilization of the two elite breeding lines were discussed.

  6. Evaluation of cutting force and surface roughness in high-speed milling of compacted graphite iron

    Directory of Open Access Journals (Sweden)

    Azlan Suhaimi Mohd

    2017-01-01

    Full Text Available Compacted Graphite Iron, (CGI is known to have outstanding mechanical strength and weight-to-strength ratio as compared to conventional grey cast iron, (CI. The outstanding characteristics of CGI is due to its graphite particle shape, which is presented as compacted vermicular particle. The graphite is interconnected with random orientation and round edges, which results in higher mechanical strength. Whereas, graphite in the CI consists of a smooth-surfaced flakes that easily propagates cracks which results in weaker and brittle properties as compared to CGI. Owing to its improved properties, CGI is considered as the best candidate material in substituting grey cast iron that has been used in engine block applications for years. However, the smooth implementation of replacing CI with CGI has been hindered due to the poor machinability of CGI especially at high cutting speed. The tool life is decreased by 20 times when comparing CGI with CI under the same cutting condition. This study investigates the effect of using cryogenic cooling and minimum quantity lubrication (MQL during high-speed milling of CGI (grade 450. Results showed that, the combination of internal cryogenic cooling and enhanced MQL improved the tool life, cutting force and surface quality as compared to the conventional flood coolant strategy during high-speed milling of CGI.

  7. Iron refractory iron deficiency anemia

    OpenAIRE

    De Falco, Luigia; Sanchez, Mayka; Silvestri, Laura; Kannengiesser, Caroline; Muckenthaler, Martina U; Iolascon, Achille; Gouya, Laurent; Camaschella, Clara; Beaumont, Carole

    2013-01-01

    Iron refractory iron deficiency anemia is a hereditary recessive anemia due to a defect in the TMPRSS6 gene encoding Matriptase-2. This protein is a transmembrane serine protease that plays an essential role in down-regulating hepcidin, the key regulator of iron homeostasis. Hallmarks of this disease are microcytic hypochromic anemia, low transferrin saturation and normal/high serum hepcidin values. The anemia appears in the post-natal period, although in some cases it is only diagnosed in ad...

  8. Convergent evolution of complex brains and high intelligence.

    Science.gov (United States)

    Roth, Gerhard

    2015-12-19

    Within the animal kingdom, complex brains and high intelligence have evolved several to many times independently, e.g. among ecdysozoans in some groups of insects (e.g. blattoid, dipteran, hymenopteran taxa), among lophotrochozoans in octopodid molluscs, among vertebrates in teleosts (e.g. cichlids), corvid and psittacid birds, and cetaceans, elephants and primates. High levels of intelligence are invariantly bound to multimodal centres such as the mushroom bodies in insects, the vertical lobe in octopodids, the pallium in birds and the cerebral cortex in primates, all of which contain highly ordered associative neuronal networks. The driving forces for high intelligence may vary among the mentioned taxa, e.g. needs for spatial learning and foraging strategies in insects and cephalopods, for social learning in cichlids, instrumental learning and spatial orientation in birds and social as well as instrumental learning in primates.

  9. Abnormal brain processing of pain in migraine without aura: a high-density EEG brain mapping study

    DEFF Research Database (Denmark)

    Egsgaard, L L; Jensen, R; Buchgreitz, L

    2010-01-01

    In the present study we used high-density EEG brain mapping to investigate spatio-temporal aspects of brain activity in response to experimentally induced muscle pain in 17 patients with migraine without aura and 15 healthy controls. Painful electrical stimuli were applied to the trapezius muscle...... to the tonic muscle pain condition (z = 29 mm vs. z =¿-13 mm, P aura....

  10. Hot Corrosion Behavior of High-Chromium, High-Carbon Cast Irons in NaCl-KCl Molten Salts

    Directory of Open Access Journals (Sweden)

    S. Vuelvas-Rayo

    2012-01-01

    Full Text Available A study on the corrosion behavior of a series of experimental high-chromium (18.53–30.48 wt.%, high-carbon (3.82–5.17% cast irons in NaCl-KCl (1 : 1 M at 670°C has been evaluated by using weight loss technique and compared with a 304-type stainless steel. It was found that all castings had a higher corrosion rate than conventional 304SS and that the addition of Cr increased the degradation rate of the cast irons. Additionally, corrosion rate increased by increasing the C contents up to 4.29%, but it decreased with a further increase in its contents. Results are discussed in terms of consumption of the Cr2O3 layer by the melt.

  11. Iron, zinc and copper in the Alzheimer's disease brain: a quantitative meta-analysis. Some insight on the influence of citation bias on scientific opinion.

    Science.gov (United States)

    Schrag, Matthew; Mueller, Claudius; Oyoyo, Udochukwu; Smith, Mark A; Kirsch, Wolff M

    2011-08-01

    Dysfunctional homeostasis of transition metals is believed to play a role in the pathogenesis of Alzheimer's disease (AD). Although questioned by some, brain copper, zinc, and particularly iron overload are widely accepted features of AD which have led to the hypothesis that oxidative stress generated from aberrant homeostasis of these transition metals might be a pathogenic mechanism behind AD. This meta-analysis compiled and critically assessed available quantitative data on brain iron, zinc and copper levels in AD patients compared to aged controls. The results were very heterogeneous. A series of heavily cited articles from one laboratory reported a large increase in iron in AD neocortex compared to age-matched controls (piron and this bias was particularly prominent among narrative review articles. Additionally, while zinc was not significantly changed in the neocortex (p=0.29), copper was significantly depleted in AD (p=0.0003). In light of these findings, it will be important to re-evaluate the hypothesis that transition metal overload accounts for oxidative injury noted in AD.

  12. Comparison of High-Temperature Properties and Thermal Shock Resistance of Austempered Ductile Irons (ADI) with Those of Pearlitic Ductile Cast Irons

    Science.gov (United States)

    Ajabshiri, Mehrdad; Sharafi, Shahriar; Moeini, Alireza

    2012-01-01

    High-temperature strength and thermal shock resistance of austempered ductile iron (ADI) in high temperatures because of instability of ausferrite phase has been less interest. The aim of this study is to investigate the tensile properties of ADI and pearlitic ductile cast iron by using the short-time tensile test in high temperatures. Tensile test was conducted in temperatures of 298 K, 673 K, 873 K, and 1073 K (25 °C, 400 °C, 600 °C, and 800 °C). Thermal shock test also was conducted by using the molten lead bath at 1273 K (1000 °C). In this experiment, samples of pearlitic ductile cast iron and ADI were divided in two groups; that after immersing in the molten lead bath for 25 seconds, one group was cooled in the air and other one was quenched in the water. Results showed that strength and thermal shock resistance of ADI samples are higher than those of the pearlitic ductile cast iron.

  13. Significance of High-frequency Electrical Brain Activity.

    Science.gov (United States)

    Kobayashi, Katsuhiro; Akiyama, Tomoyuki; Agari, Takashi; Sasaki, Tatsuya; Shibata, Takashi; Hanaoka, Yoshiyuki; Akiyama, Mari; Endoh, Fumika; Oka, Makio; Date, Isao

    2017-06-01

     Electroencephalogram (EEG) data include broadband electrical brain activity ranging from infra-slow bands (frequency bands (e.g., the approx. 10 Hz alpha rhythm) to high-frequency bands of up to 500 Hz. High-frequency oscillations (HFOs) including ripple and fast ripple oscillations (80-200 Hz and>200 / 250 Hz, respectively) are particularly of note due to their very close relationship to epileptogenicity, with the possibility that they could function as a surrogate biomarker of epileptogenicity. In contrast, physiological high-frequency activity plays an important role in higher brain functions, and the differentiation between pathological / epileptic and physiological HFOs is a critical issue, especially in epilepsy surgery. HFOs were initially recorded with intracranial electrodes in patients with intractable epilepsy as part of a long-term invasive seizure monitoring study. However, fast oscillations (FOs) in the ripple and gamma bands (40-80 Hz) are now noninvasively detected by scalp EEG and magnetoencephalography, and thus the scope of studies on HFOs /FOs is rapidly expanding.

  14. In-situ Characterization and Mapping of Iron Compounds in Alzheimer's Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Collingwood, J F; Mikhaylova, A; Davidson, M; Batich, C; Streit, W J; Terry, J; Dobson, J [IIT; (Keele); (Florida)

    2008-06-16

    There is a well-established link between iron overload in the brain and pathology associated with neurodegeneration in a variety of disorders such as Alzheimer's (AD), Parkinson's (PD) and Huntington's (HD) diseases. This association was first discovered in AD by Goodman in 1953, where, in addition to abnormally high concentrations of iron in autopsy brain tissue, iron has also been shown to accumulate at sites of brain pathology such as senile plaques. However, since this discovery, progress in understanding the origin, role and nature of iron compounds associated with neurodegeneration has been slow. Here we report, for the first time, the location and characterization of iron compounds in human AD brain tissue sections. Iron fluorescence was mapped over a frontal-lobe tissue section from an Alzheimer's patient, and anomalous iron concentrations were identified using synchrotron X-ray absorption techniques at 5 {micro}m spatial resolution. Concentrations of ferritin and magnetite, a magnetic iron oxide potentially indicating disrupted brain-iron metabolism, were evident. These results demonstrate a practical means of correlating iron compounds and disease pathology in-situ and have clear implications for disease pathogenesis and potential therapies.

  15. The AFT1 transcriptional factor is differentially required for expression of high-affinity iron uptake genes in Saccharomyces cerevisiae.

    Science.gov (United States)

    Casas, C; Aldea, M; Espinet, C; Gallego, C; Gil, R; Herrero, E

    1997-06-15

    High-affinity iron uptake in Saccharomyces cerevisiae involves the extracytoplasmic reduction of ferric ions by FRE1 and FRE2 reductases. Ferrous ions are then transported across the plasma membrane through the FET3 oxidase-FTR1 permease complex. Expression of the high-affinity iron uptake genes is induced upon iron deprivation. We demonstrate that AFT1 is differentially involved in such regulation. Aft1 protein is required for maintaining detectable non-induced level of FET3 expression and for induction of FRE2 in iron starvation conditions. On the contrary, FRE1 mRNA induction is normal in the absence of Aft1, although the existence of AFT1 point mutations causing constitutive expression of FRE1 (Yamaguchi-Iwai et al., EMBO J. 14: 1231-1239, 1995) indicates that Aft1 may also participate in FRE1 expression in a dispensable way. The alterations in the basal levels of expression of the high-affinity iron uptake genes may explain why the AFT1 mutant is unable to grow on respirable carbon sources. Overexpression of AFT1 leads to growth arrest of the G1 stage of the cell cycle. Aft1 is a transcriptional activator that would be part of the different transcriptional complexes interacting with the promoter of the high-affinity iron uptake genes. Aft1 displays phosphorylation modifications depending on the growth stage of the cells, and it might link induction of genes for iron uptake to other metabolically dominant requirement for cell growth.

  16. Corrosion of high-level radioactive waste iron-canisters in contact with bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Kaufhold, Stephan, E-mail: s.kaufhold@bgr.de [BGR, Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover (Germany); Hassel, Achim Walter [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, D-40237 Düsseldorf (Germany); Institute for Chemical Technology of Inorganic Materials, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz (Austria); Sanders, Daniel [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, D-40237 Düsseldorf (Germany); Dohrmann, Reiner [BGR, Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover (Germany); LBEG, Landesamt für Bergbau, Energie und Geologie, Stilleweg 2, D-30655 Hannover (Germany)

    2015-03-21

    Graphical abstract: Corrosion at the bentonite iron interface proceeds unaerobically with formation of an 1:1 Fe silicate mineral. A series of exposure tests with different types of bentonites showed that Na–bentonites are slightly less corrosive than Ca–bentonites and highly charges smectites are less corrosive compared to low charged ones. The formation of a patina was observed in some cases and has to be investigated further. - Highlights: • At the iron bentonite interface a 1:1 Fe layer silicate forms upon corrosion. • A series of iron–bentonite corrosion products showed slightly less corrosion for Na-rich and high-charged bentonites. • In some tests the formation of a patina was observed consisting of Fe–silicate, which has to be investigated further. - Abstract: Several countries favor the encapsulation of high-level radioactive waste (HLRW) in iron or steel canisters surrounded by highly compacted bentonite. In the present study the corrosion of iron in contact with different bentonites was investigated. The corrosion product was a 1:1 Fe layer silicate already described in literature (sometimes referred to as berthierine). Seven exposition test series (60 °C, 5 months) showed slightly less corrosion for the Na–bentonites compared to the Ca–bentonites. Two independent exposition tests with iron pellets and 38 different bentonites clearly proved the role of the layer charge density of the swelling clay minerals (smectites). Bentonites with high charged smectites are less corrosive than bentonites dominated by low charged ones. The type of counterion is additionally important because it determines the density of the gel and hence the solid/liquid ratio at the contact to the canister. The present study proves that the integrity of the multibarrier-system is seriously affected by the choice of the bentonite buffer encasing the metal canisters in most of the concepts. In some tests the formation of a patina was observed consisting of Fe

  17. Erosion-corrosion investigation of high chromium cast irons using newly designed jet type tester

    Institute of Scientific and Technical Information of China (English)

    TU Xiao-hui; LIU Jun-quan; LI Wei; ZHANG Feng-hua; SU Jun-yi

    2004-01-01

    A jet type erosion-corrosion tester was developed for the erosion-corrosion investigation of high-chromium cast irons. During tests the size and the shape of particles in the slurry can be maintained stable. The jet velocity and attack angle can be accurately controlled. The repeatability and ranking consistency of the test results are satisfactory. The test parameters can be adjusted in a wide range, so that the tester can simulate various practical working conditions. Electrochemical test data can be automatically collected and processed. Dynamic polarization curves can be obtained during erosion-corrosion test, which can be used to study the dynamic corrosion characteristics.Two high chromium cast irons were studied in hot concentrated alkaline slurry. The results show that the erosioncorrosion mass loss rate and dynamic corrosion rate of 295Cr26 iron is lower than that of 185Cr13 under the conditions similar to alumyte processing. The mechanism of erosion-corrosion of 295Cr26 and 185Cr13 was studied by using the tester. The interaction between erosion and corrosion was also quantitatively evaluated.

  18. Development of a New Foxtail Millet Germplasm with Super Early Maturity and High Iron Content

    Institute of Scientific and Technical Information of China (English)

    LIU Zheng-li; SUN Shi-xian; CHENG Ru-hong; HUANG Wen-sheng; LIU Jun-xin; QU Zhu-feng; XIA Xue-yan; SHI Zhi-gang

    2006-01-01

    Super Early Maturation No.2 is a new foxtail millet germplasm developed by using the targeted-character-gene-bankbreeding method. It has several outstanding characteristics. (1) Super early maturity. It can normally mature in Bashang,Hebei Province, China, where the altitude is around 1 400 meters, and it needs 1 650℃ of effective accumulated temperature in the growing period. (2) Millet is rich in iron. The iron content of the millet of Super Early Maturation No.2 is 54.10 mg kg-1,which is 62.0% higher than the average iron content of the foxtail millet varieties in China. (3) High crude fat content. Its crude fat content is 6.24%, which is 54.1% higher than the average content of foxtail millet varieties in China. (4) High crude protein content. The average of the crude protein content of all the foxtail millet varieties in China is 12.71%, only5% varieties surpass 14%, however, the crude protein content of Super Early Maturation No.2 is 14.36%, which is rare in improved varieties of foxtail millet in China. (5) Overall characteristics are good.

  19. High-performance iron oxide nanoparticles for magnetic particle imaging - guided hyperthermia (hMPI)

    Science.gov (United States)

    Bauer, Lisa M.; Situ, Shu F.; Griswold, Mark A.; Samia, Anna Cristina S.

    2016-06-01

    Magnetic particle imaging (MPI) is an emerging imaging modality that allows the direct and quantitative mapping of iron oxide nanoparticles. In MPI, the development of tailored iron oxide nanoparticle tracers is paramount to achieving high sensitivity and good spatial resolution. To date, most MPI tracers being developed for potential clinical applications are based on spherical undoped magnetite nanoparticles. For the first time, we report on the systematic investigation of the effects of changes in chemical composition and shape anisotropy on the MPI performance of iron oxide nanoparticle tracers. We observed a 2-fold enhancement in MPI signal through selective doping of magnetite nanoparticles with zinc. Moreover, we demonstrated focused magnetic hyperthermia heating by adapting the field gradient used in MPI. By saturating the iron oxide nanoparticles outside of a field free region (FFR) with an external static field, we can selectively heat a target region in our test sample. By comparing zinc-doped magnetite cubic nanoparticles with undoped spherical nanoparticles, we could show a 5-fold improvement in the specific absorption rate (SAR) in magnetic hyperthermia while providing good MPI signal, thereby demonstrating the potential for high-performance focused hyperthermia therapy through an MPI-guided approach (hMPI).Magnetic particle imaging (MPI) is an emerging imaging modality that allows the direct and quantitative mapping of iron oxide nanoparticles. In MPI, the development of tailored iron oxide nanoparticle tracers is paramount to achieving high sensitivity and good spatial resolution. To date, most MPI tracers being developed for potential clinical applications are based on spherical undoped magnetite nanoparticles. For the first time, we report on the systematic investigation of the effects of changes in chemical composition and shape anisotropy on the MPI performance of iron oxide nanoparticle tracers. We observed a 2-fold enhancement in MPI signal

  20. Spin States of Iron(III) in Highly Saddled Dodecaphenylporphyrin Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ohya, T., E-mail: ohyat@pharm.teikyo-u.ac.jp; Takeda, J.; Sato, M. [Teikyo University, Laboratory of Biophysics, Faculty of Pharmaceutical Sciences (Japan)

    2004-12-15

    Iron(III) complexes of highly saddled dodecaphenylporphyrin, Fe(DPP)X (X=Cl, Br or I) have been prepared and characterized by Moessbauer, UV-Vis and magnetic measurements. The Moessbauer spectra, recorded at temperatures from 5 to 300 K, contain two components A and B. Component A is attributed to iron(III) in a spin-admixed (S=3/2, 5/2) state. The UV-Vis spectra of solution samples of these complexes exhibit broad and red-shifted absorption bands. The effective magnetic moments derived from the molar magnetic susceptibilities measured by modified Gouy method at 298 K for X=Cl, Br and I are 5.52, 5.10 and 4.28 {mu}{sub B}, respectively.

  1. Cast irons

    CERN Document Server

    1996-01-01

    Cast iron offers the design engineer a low-cost, high-strength material that can be easily melted and poured into a wide variety of useful, and sometimes complex, shapes. This latest handbook from ASM covers the entire spectrum of one of the most widely used and versatile of all engineered materials. The reader will find the basic, but vital, information on metallurgy, solidification characteristics, and properties. Extensive reviews are presented on the low-alloy gray, ductile, compacted graphite, and malleable irons. New and expanded material has been added covering high-alloy white irons used for abrasion resistance and high-alloy graphitic irons for heat and corrosion resistance. Also discussed are melting furnaces and foundry practices such as melting, inoculation, alloying, pouring, gating and rising, and molding. Heat treating practices including stress relieving, annealing, normalizing, hardening and tempering, autempering (of ductile irons), and surface-hardening treatments are covered, too. ASM Spec...

  2. Geology and geochemistry of the Macheng Algoma-type banded iron-formation, North China Craton: Constraints on mineralization events and genesis of high-grade iron ores

    Science.gov (United States)

    Wu, Huaying; Niu, Xianglong; Zhang, Lianchang; Pirajno, Franco; Luo, Huabao; Qin, Feng; Cui, Minli; Wang, Changle; Qi, Min

    2015-12-01

    The Macheng iron deposit is located in the eastern Hebei province of the North China Craton (NCC). It is hosted in Neoarchean metamorphic rocks of Baimiaozi formation in the Dantazi Group, consisting of biotite-leptynite, plagioclase-gneiss, plagioclase-amphibolite, migmatite, migmatitic granite and quartz schist. Geochemical analyses of the host biotite leptynite and plagioclase amphibolites show that their protoliths are both volcanics, inferred to be trachytic basalt and basaltic andesite, respectively. Based on the geochemical signature of the host rocks, together with geology of the iron deposit, it is inferred that the Macheng BIF is an Algoma-type iron exhalative formation, formed in an arc-related basin in the Neoarchean. Post-Archean Australian Shale (PAAS)-normalized rare earth elements (REEs) plus yttrium (Y) concentrations of different BIF ores with gneissic, striated and banded structure in the Macheng deposit, show similar patterns with depletions in light rare earth elements (LREEs) and middle rare earth elements (MREEs) relative to heavy rare earth elements (HREEs) and with apparently positive La, Y and Eu anomalies. Y/Ho ratios of the gneissic, striated and banded BIF ores vary from 37 to 56. These geochemical features of the BIF ores reveal their affinity with the sea water and the presence of a high-temperature hydrothermal component, indicating that both the seawater and high temperature hydrothermal fluids derived from alteration of oceanic basalts and komatiites may contribute to formation of the Macheng BIF. Geological, mineralogical and geochemical studies of the Macheng deposit recognized two kinds of high-grade iron ores. One is massive oxidized high-grade ore (Fe2O3T = 74.37-86.20 wt.%), mainly consisting of hematite with some magnetite, which shows geochemical characteristics of the gneissic, striated and banded BIF ores. The other type is magnetite high-grade ore, also massive and consisting of magnetite, with distinct characteristics

  3. Iron load

    Directory of Open Access Journals (Sweden)

    Filippo Cassarà

    2013-03-01

    Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.

  4. Methods of synthesis and performance improvement of lithium iron phosphate for high rate Li-ion batteries: A review

    Directory of Open Access Journals (Sweden)

    T.V.S.L. Satyavani

    2016-03-01

    Full Text Available Lithium ion battery technology has the potential to meet the requirements of high energy density and high power density applications. A continuous search for novel materials is pursued continually to exploit the latent potential of this technology. In this review paper, methods for preparation of Lithium Iron Phosphate are discussed which include solid state and solution based synthesis routes. The methods to improve the electrochemical performance of lithium iron phosphate are presented in detail.

  5. Methods of synthesis and performance improvement of lithium iron phosphate for high rate Li-ion batteries: A review

    OpenAIRE

    T.V.S.L. Satyavani; Srinivas Kumar, A.; P.S.V. Subba Rao

    2016-01-01

    Lithium ion battery technology has the potential to meet the requirements of high energy density and high power density applications. A continuous search for novel materials is pursued continually to exploit the latent potential of this technology. In this review paper, methods for preparation of Lithium Iron Phosphate are discussed which include solid state and solution based synthesis routes. The methods to improve the electrochemical performance of lithium iron phosphate are presented in d...

  6. Early Brain changes May Help Predict Autism Among High-Risk Infants

    Science.gov (United States)

    ... Media Resources Interviews & Selected Staff Profiles Multimedia Early brain changes may help predict autism among high-risk ... Share this: Page Content NIH-funded researchers link brain changes at 6 and 12 months of age ...

  7. High-Throughput Screening Assay for Inhibitors of TonB-Dependent Iron Transport.

    Science.gov (United States)

    Hanson, Mathew; Jordan, Lorne D; Shipelskiy, Yan; Newton, Salete M; Klebba, Phillip E

    2016-03-01

    The TonB-dependent Gram-negative bacterial outer membrane protein FepA actively transports the siderophore ferric enterobactin (FeEnt) into the periplasm. We developed a high-throughput screening (HTS) assay that observes FeEnt uptake through FepA in living Escherichia coli, by monitoring fluorescence quenching that occurs upon binding of FeEnt, and then unquenching as the bacteria deplete it from solution by transport. We optimized the labeling and spectroscopic methods to screen for inhibitors of TonB-dependent iron uptake through the outer membrane. The assay works like a molecular switch that is on in the presence of TonB activity and off in its absence. It functions in 96-well microtiter plates, in a variety of conditions, with Z factors of 0.8-1.0. TonB-dependent iron transport is energy dependent, and the inhibitory effects of the metabolic inhibitors carbonyl cyanide m-chlorophenylhydrazone, 2,4-dinitrophenol, azide, cyanide, and arsenate on FeEnt uptake were readily detected by the assay. Because iron acquisition is a determinant of bacterial pathogenesis, HTS with this method may identify inhibitors that block TonB function and constitute novel therapeutics against infectious disease caused by Gram-negative bacteria. © 2015 Society for Laboratory Automation and Screening.

  8. Vitamin D, Iron Metabolism, and Diet in Alpinists During a 2-Week High-Altitude Climb.

    Science.gov (United States)

    Kasprzak, Zbigniew; Śliwicka, Ewa; Hennig, Karol; Pilaczyńska-Szcześniak, Łucja; Huta-Osiecka, Anna; Nowak, Alicja

    2015-09-01

    A defensive mechanism against hypobaric hypoxia at high altitude is erythropoesis. Some authors point to the contribution of vitamin D to the regulation of this process. The aim of the present study was to assess the 25-hydroxycholecalciferol (25(OH)D) level and its associations with iron metabolic and inflammatory indices in participants of a 2-week mountaineering expedition. The study sample included 9 alpinists practicing recreational mountain climbing. Every 2 or 3 days they set up a different base between 3200 and 3616 m with the intention of climbing 4000 m peaks in the Mont Blanc massif. Before their departure for the mountains and 2 days after returning to the sea level anthropometric parameters, hematological parameters, serum levels of 25(OH)D and iron metabolic indices were measured in all the participants. The composition of the participants' diet was also evaluated. The comparative analysis showed a significant decrease in body mass, BMI values, total iron, and 25(OH)D concentrations (pclimbing expedition contributed to the reduction of 25(OH)D levels and these changes were associated with modulation of immune processes. Moreover, the climbers' diet requires some serious modifications.

  9. Glass ceramic of high hardness and fracture toughness developed from iron-rich wastes

    Institute of Scientific and Technical Information of China (English)

    Weixin HAN

    2009-01-01

    A study has been carried out on the feasibility of using high iron content wastes, gen-erated during steel making, as a raw material for the production of glass ceramic. The iron-rich wastes were mixed and melted in different proportions with soda-lime glass cullet and sand. The devitrification of the parent glasses produced from the different mixtures was investigated using differential thermal analysis, X-ray diffraction, and scanning electron microscopy. The mechanical properties of the glass-ceramic were assessed by hardness and indentation fracture toughness measurement. A glass ce-ramic with mixture of 60 wt pct iron-rich wastes, 25 wt pct sand, and 15 wt pct glass cullet exhibited the best combination of properties, namely, hardness 7.9 GPa and fracture toughness 3.75 MPa.m1/2, for the sake of containing magnetite in marked dendritic morphology. These new hard glass ceramics are candidate materials for wear resistant tiles and paving for heavy industrial floors.

  10. Advances in Glass Formulations for Hanford High-Alumimum, High-Iron and Enhanced Sulphate Management in HLW Streams - 13000

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A.

    2013-01-16

    The current estimates and glass formulation efforts have been conservative in terms of achievable waste loadings. These formulations have been specified to ensure that the glasses are homogenous, contain essentially no crystalline phases, are processable in joule-heated, ceramic-lined melters and meet Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract terms. The WTP?s overall mission will require the immobilization of tank waste compositions that are dominated by mixtures of aluminum (Al), chromium (Cr), bismuth (Bi), iron (Fe), phosphorous (P), zirconium (Zr), and sulphur (S) compounds as waste-limiting components. Glass compositions for these waste mixtures have been developed based upon previous experience and current glass property models. Recently, DOE has initiated a testing program to develop and characterize HLW glasses with higher waste loadings and higher throughput efficiencies. Results of this work have demonstrated the feasibility of increases in waste loading from about 25 wt% to 33-50 wt% (based on oxide loading) in the glass depending on the waste stream. In view of the importance of aluminum limited waste streams at Hanford (and also Savannah River), the ability to achieve high waste loadings without adversely impacting melt rates has the potential for enormous cost savings from reductions in canister count and the potential for schedule acceleration. Consequently, the potential return on the investment made in the development of these enhancements is extremely favorable. Glass composition development for one of the latest Hanford HLW projected compositions with sulphate concentrations high enough to limit waste loading have been successfully tested and show tolerance for previously unreported tolerance for sulphate. Though a significant increase in waste loading for high-iron wastes has been achieved, the magnitude of the increase is not as substantial as those achieved for high-aluminum, high-chromium, high-bismuth or sulphur

  11. Effects of Radiation and a High Iron Load on Bone Mineral Density

    Science.gov (United States)

    Yuen, E.; Morgan, J. L. L.; Zwart, S. R.; Gonzales, E.; Camp, K.; Smith, S. M.; Bloomfield, S. A.

    2012-01-01

    Astronauts on long duration space flight missions to the moon or mars are exposed to radiation and have increase iron (Fe) stores, both of which can independently induce oxidative stress and may exacerbate bone mass loss and strength. We hypothesize a high Fe diet and a fractionated gamma radiation exposure would increase oxidative stress and lower bone mass. Three mo-old, SD rats (n=32) were randomized to receive an adequate Fe diet (45 mg Fe/kg diet) or a high Fe diet (650 mg Fe/kg diet) for 4 wks and either a cumulative 3 Gy dose (fractionated 8 x 0.375 Gy) of gamma radiation (Cs-137) or sham exposure starting on day 14. Elisa kit assessed serum catalase, clinical analyzer assessed serum Fe status and ex vivo pQCT scans measured bone parameters in the proximal/midshaft tibia and femoral neck. Mechanical strength was assessed by 3-pt bending and femoral neck test. There is a significant decrease in trabecular bone mineral density (BMD) from radiation (p less than 0.05) and a trend in diet (p=0.05) at the proximal tibia. There is a significant interaction in cortical BMD from the combined treatments at the midshaft tibia (p less than 0.05). There is a trending decrease in total BMD from diet (p=0.07) at the femoral neck. In addition, high serum Fe was correlated to low trabecular BMD (p less than 0.05) and high serum catalase was correlated to low BMD at all 3 bone sites (p less than 0.05). There was no difference in the max load of the tibia or femoral neck. Radiation and a high iron diet increases iron status and catalase in the serum and decreases BMD.

  12. Properties and solubility of chrome in iron alumina phosphate glasses containing high level nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Huang, W. [School of Materials Science and Engineering, Tongji Univ., Shanghai, SH (China); Day, D.E.; Ray, C.S.; Kim, C.W.; Reis, S.T.D. [Univ. of Missouri-Rolla (United States). Graduate Center for Materials Research

    2004-10-01

    Chemical durability, glass formation tendency, and other properties of iron alumina phosphate glasses containing 70 wt% of a simulated high level nuclear waste (HLW), doped with different amounts of Cr{sub 2}O{sub 3}, have been investigated. All of the iron alumina phosphate glasses had an outstanding chemical durability as measured by their small dissolution rate (1 . 10{sup -9} g/(cm{sup 2} . min)) in deionized water at 90 C for 128 d, their low normalized mass release as determined by the product consistency test (PCT) and a barely measurable corrosion rate of <0.1 g/(m{sup 2} . d) after 7 d at 200 C by the vapor hydration test (VHT). The solubility limit for Cr{sub 2}O{sub 3} in the iron phosphate melts was estimated at 4.1 wt%, but all of the as-annealed melts contained a few percent of crystalline Cr{sub 2}O{sub 3} that had no apparent effect on the chemical durability. The chemical durability was unchanged after deliberate crystallization, 48 h at 650 C. These iron phosphate waste forms, with a waste loading of at least 70 wt%, can be readily melted in commercial refractory crucibles at 1250 C for 2 to 4 h, are resistant to crystallization, meet all current US Department of Energy requirements for chemical durability, and have a solubility limit for Cr{sub 2}O{sub 3} which is at least three times larger than that for borosilicate glasses. (orig.)

  13. Blood-Brain Barrier Changes in High Altitude.

    Science.gov (United States)

    Lafuente, José V; Bermudez, Garazi; Camargo-Arce, Lorena; Bulnes, Susana

    2016-01-01

    Cerebral syndromes related to high-altitude exposure are becoming more frequent as the number of trips to high altitudes has increased in the last decade. The commonest symptom is headache, followed by acute mountain sickness (AMS) and high-altitude cerebral edema (HACE), which can be fatal. The pathophysiology of these syndromes is not fully understood. The classical "tight-fit hypothesis" posits that there are some anatomical variations that would obstruct the sinovenous outflow and worsen vasogenic edema and intracranial hypertension reactive to hypoxia. This could explain microhemorrhages seen in autopsies. However, recent magnetic resonance imaging studies have demonstrated some components of cytotoxic edema in HACE absent in AMS, suggesting a dysfunction in water balance at the cellular level. Currently, the "red-ox theory" supports trigemino-vascular system activation by free radicals formed after hypoxia and the consequent oxidative stress cascades. Apart from trigemino-vascular system activation, free radicals can also provoke membrane destabilisation mediated by lipid peroxidation, inflammation, and local hypoxia inducible factor-1α and vascular endothelial growth factor activation, resulting in gross blood-brain barrier (BBB) dysfunction. Besides alterations in endothelial cells such as increased pinocytotic vesicles and disassembly of interendothelial tight junction proteins, capillary permeability may also increase with subsequent swelling of astrocyte end-feet. In conclusion, although the pathophysiology of AMS and HACE is not completely understood, recent evidence proposes a multifactorial entity, with brain swelling and compromise of the BBB considered to play an important role. A fuller comprehension of these processes is crucial to reduce and prevent BBB alterations during high-altitude exposure.

  14. High-temperature XRD study of thermally induced structural and chemical changes in iron oxide nanoparticles embedded in porous carbons

    Energy Technology Data Exchange (ETDEWEB)

    Schettino, M. A.; Freitas, J. C. C., E-mail: jairccfreitas@yahoo.com.b [Universidade Federal do Espirito Santo, Departamento de Fisica (Brazil); Morigaki, M. K. [Universidade Federal do Espirito Santo, Departamento de Quimica (Brazil); Nunes, E.; Cunha, A. G.; Passamani, E. C.; Emmerich, F. G. [Universidade Federal do Espirito Santo, Departamento de Fisica (Brazil)

    2010-10-15

    Magnetic carbon-based nanomaterials have promising applications in many fields owing to their biocompatibility and thermal/mechanical stability. This study describes a high-temperature X-ray diffraction (XRD) study of the chemical and structural transformations suffered by superparamagnetic iron oxide nanoparticles embedded in porous carbons. The nanoparticles were prepared from the decomposition of iron pentacarbonyl over porous carbons, resulting in nanometer-sized iron oxides homogeneously dispersed into the carbon matrix. The thermally induced changes in these materials were followed by in situ high-temperature XRD, using synchrotron radiation. The growing of the nanoparticles and of the carbon crystallites were first observed, followed by the reduction of the iron oxides to form {alpha}-Fe (at temperatures as low as 400 {sup o}C in some cases) and {gamma}-Fe(C). The temperatures at which these chemical reactions occurred were dependent on the total time spent on heating and on the nature of the iron oxides formed in the as prepared materials. A noticeably large thermal expansion coefficient was also observed for the iron oxide nanocrystals. The formation of austenitic iron, stabilized by the presence of carbon, was found to be only partially reversible upon cooling.

  15. Effect of Dietary Iron on Fetal Growth in Pregnant Mice

    Science.gov (United States)

    Hubbard, Andrea C; Bandyopadhyay, Sheila; Wojczyk, Boguslaw S; Spitalnik, Steven L; Hod, Eldad A; Prestia, Kevin A

    2013-01-01

    Iron deficiency is the most common nutritional disorder. Children and pregnant women are at highest risk for developing iron deficiency because of their increased iron requirements. Iron-deficiency anemia during pregnancy is associated with adverse effects on fetal development, including low birth weight, growth retardation, hypertension, intrauterine fetal death, neurologic impairment, and premature birth. We hypothesized that pregnant mice fed an iron-deficient diet would have a similar outcome regarding fetal growth to that of humans. To this end, we randomly assigned female C57BL/6 mice to consume 1 of 4 diets (high-iron–low-bioavailability, high-iron–high-bioavailability, iron-replete, and iron-deficient) for 4 wk before breeding, followed by euthanasia on day 17 to 18 of gestation. Compared with all other groups, dams fed the high-iron–high-bioavailability diet had significantly higher liver iron. Hct and Hgb levels in dams fed the iron-deficient diet were decreased by at least 2.5 g/dL as compared with those of all other groups. In addition, the percentage of viable pups among dams fed the iron-deficient diet was lower than that of all other groups. Finally, compared with all other groups, fetuses from dams fed the iron-deficient diet had lower fetal brain iron levels, shorter crown–rump lengths, and lower weights. In summary, mice fed an iron-deficient diet had similar hematologic values and fetal outcomes as those of iron-deficient humans, making this a useful model for studying iron-deficiency anemia during pregnancy. PMID:23582419

  16. In Vivo Single Scan Detection of Both Iron-Labeled Cells and Breast Cancer Metastases in the Mouse Brain Using Balanced Steady-State Free Precession Imaging at 1.5 T

    Science.gov (United States)

    Ribot, Emeline J.; Martinez-Santiesteban, Francisco M.; Simedrea, Carmen; Steeg, Patricia S.; Chambers, Ann F.; Rutt, Brian K.; Foster, Paula J.

    2012-01-01

    Purpose To simultaneously detect iron-labeled cancer cells and brain tumors in vivo in one scan, the balanced steady-state free precession (b-SSFP) imaging sequence was optimized at 1.5 T on mice developing brain metastases subsequent to the injection of micron-sized iron oxide particle-labeled human breast cancer cells. Materials and Methods b-SSFP sequence parameters (repetition time, flip angle, and receiver bandwidth) were varied and the signal-to-noise ratio, contrast between the brain and tumors, and the number of detected iron-labeled cells were evaluated. Results Optimal b-SSFP images were acquired with a 26 msec repetition time, 35° flip angle, and bandwidth of ±21 kHz. b-SSFP images were compared with T2-weighted 2D fast spin echo (FSE) and 3D spoiled gradient recalled echo (SPGR) images. The mean tumor-brain contrast-to-noise ratio and the ability to detect iron-labeled cells were the highest in the b-SSFP images. Conclusion A single b-SSFP scan can be used to visualize both iron-labeled cells and brain metastases. PMID:21698713

  17. Stability and Elasticity of High Iron and Aluminum Post-Perovskite Phases and Their Implications for the D" Layer

    Science.gov (United States)

    Shieh, S. R.; Duffy, T. S.; Kubo, A.; Prakapenka, V. B.

    2008-12-01

    To evaluate the iron and aluminum effects on the post-perovskite phase at deep mantle conditions, it is important to study the potential mantle silicates containing both iron and aluminum. In this study, three different compositions of natural garnet along pyrope-almandine join, Pyr21Alm73Gr5, Pyr43Alm54Gr2, Pyr58Alm38Gr3, were used as starting materials to investigate the stability and elasticity of high iron- and aluminum-bearing post-perovskite phase at deep mantle conditions. In situ high-pressure and high- temperature experiments were conducted at beamline 13-ID-D of GSECARS, Advanced Photon Source. A monochromatic beam with a wavelength of 0.3044 Å and a MAR CCD detector were used for X-ray diffraction data collections. Samples were loaded in the symmetrical diamond-anvil cells and heated by the double-sided laser heating system. Our results showed that the post-perovskite phase can be successfully synthesized from three different compositions at pressure greater than 160 GPa and temperature higher than 1600 K. This indicates that the post-perovskite phase can simultaneously accommodate high aluminum and high iron contents. However, Al2O3-post-perovskite phase can also be observed from some runs for Pyr43Alm54Gr2 and Pyr58Alm38Gr3, showing that there is actually a limit for incorporating the aluminum into the post-perovskite phase but not for iron. In addition, we also found that the volume of post- perovskite phases can also be affected by the incorporated amount of iron. Our pressure-volume results showed that high-iron post-perovskite phases have larger volumes and the iron effect is greater at pressure above 120 GPa.

  18. Neurorescue activity, APP regulation and amyloid-beta peptide reduction by novel multi-functional brain permeable iron- chelating- antioxidants, M-30 and green tea polyphenol, EGCG.

    Science.gov (United States)

    Avramovich-Tirosh, Yael; Reznichenko, Lydia; Mit, Tamar; Zheng, Hailin; Fridkin, Mati; Weinreb, Orly; Mandel, Silvia; Youdim, Moussa B H

    2007-09-01

    Accumulation of iron at sites where neurons degenerate in Parkinson's disease (PD) and Alzheimer's disease (AD) is thought to have a major role in oxidative stress induced process of neurodegeneration. The novel non-toxic lipophilic brain- permeable iron chelators, VK-28 (5- [4- (2- hydroxyethyl) piperazine-1-ylmethyl]- quinoline- 8- ol) and its multi-functional derivative, M-30 (5-[N-methyl-N-propargylaminomethyl]-8-hydroxyquinoline), as well as the main polyphenol constituent of green tea (-)-epigallocatechin-3-gallate (EGCG), which possesses iron metal chelating, radical scavenging and neuroprotective properties, offer potential therapeutic benefits for these diseases. M-30 and EGCG decreased apoptosis of human SH-SY5Y neuroblastoma cells in a neurorescue, serum deprivation model, via multiple protection mechanisms including: reduction of the pro-apoptotic proteins, Bad and Bax, reduction of apoptosis-associated Ser139 phosphorylated H2A.X and inhibition of the cleavage and activation of caspase-3. M-30 and EGCG also promoted morphological changes, resulting in axonal growth-associated protein-43 (GAP-43) implicating neuronal differentiation. Both compounds significantly reduced the levels of cellular holo-amyloid precursor protein (APP) in SH-SY5Y cells. The ability of theses novel iron chelators and EGCG to regulate APP are in line with the presence of an iron-responsive element (IRE) in the 5'-untranslated region (5'UTR) of APP. Also, EGCG reduced the levels of toxic amyloid-beta peptides in CHO cells over-expressing the APP "Swedish" mutation. The diverse molecular mechanisms and cell signaling pathways participating in the neuroprotective/neurorescue and APP regulation/processing actions of M-30 and EGCG, make these multifunctional compounds potential neuroprotective drugs for the treatment of neurodegenerative diseases, such as PD, AD, Huntington's disease and amyotrophic lateral sclerosis.

  19. Development and Testing of Iron Based Phantoms as Standards for the Diagnosis of Microbleeds and Oxygen Saturation with Applications in Dementia, Stroke, and Traumatic Brain Injury

    Science.gov (United States)

    2013-10-01

    each tissue in the brain model in order to generate magnitude images at main magnetic field, B0, of 3 Tesla for different echo times (TE = 4 ms, 7 ms...acquired at wiggler beam line 10–2 at SSRL. The samples were mounted onto a set of motorized stages oriented at 45° to the incident beam. The incident...Authors Correlation slopea Structures Background removal QSM methodb Myelin correction Field ( Tesla ) Sample Iron This paper 1.11 N.A. Quadratic fitting

  20. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application

    Science.gov (United States)

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-01-01

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal−air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application. PMID:28272443

  1. Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application.

    Science.gov (United States)

    Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

    2017-03-08

    Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

  2. Image reconstruction techniques for high resolution human brain PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Comtat, C.; Bataille, F.; Sureau, F. [Service Hospitalier Frederic Joliot (CEA/DSV/DRM), 91 - Orsay (France)

    2006-07-01

    High resolution PET imaging is now a well established technique not only for small animal, but also for human brain studies. The ECAT HRRT brain PET scanner(Siemens Molecular Imaging) is characterized by an effective isotropic spatial resolution of 2.5 mm, about a factor of 2 better than for state-of-the-art whole-body clinical PET scanners. Although the absolute sensitivity of the HRRT (6.5 %) for point source in the center of the field-of-view is increased relative to whole-body scanner (typically 4.5 %) thanks to a larger co-polar aperture, the sensitivity in terms of volumetric resolution (75 (m{sup 3} at best for whole-body scanners and 16 (m{sup 3} for t he HRRT) is much lower. This constraint has an impact on the performance of image reconstruction techniques, in particular for dynamic studies. Standard reconstruction methods used with clinical whole-body PET scanners are not optimal for this application. Specific methods had to be developed, based on fully 3D iterative techniques. Different refinements can be added in the reconstruction process to improve image quality: more accurate modeling of the acquisition system, more accurate modeling of the statistical properties of the acquired data, anatomical side information to guide the reconstruction . We will present the performances these added developments for neuronal imaging in humans. (author)

  3. Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Arkundato, Artoto [Physics Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Su' ud, Zaki [Physics Department, Faculty of Mathematical and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung (Indonesia); Sudarko [Chemistry Department, Faculty of Mathematical and Natural Sciences, Jember University, Jl. Kalimantan 37 Jember (Indonesia); Shafii, Mohammad Ali [Physics Department, Faculty of Mathematical and Natural Sciences, Andalas University, Padang (Indonesia); Celino, Massimo [ENEA, CR Casaccia, Via Anguillarese 301, Rome (Italy)

    2014-09-30

    Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

  4. Inhibitory effects of multiwall carbon nanotubes with high iron impurity on viability and neuronal differentiation in cultured PC12 cells.

    Science.gov (United States)

    Meng, Li; Jiang, Aihua; Chen, Rui; Li, Chen-zhong; Wang, Liming; Qu, Ying; Wang, Peng; Zhao, Yuliang; Chen, Chunying

    2013-11-08

    The increasing use of carbon nanotubes (CNTs) in biomedical applications has garnered a great concern on their potential negative effects to human health. CNTs have been reported to potentially disrupt normal neuronal function and they were speculated to accumulate and cause brain damage, although a lot of distinct and exceptional properties and potential wide applications have been associated with this material in neurobiology. Fe impurities strapped inside the CNTs may be partially responsible for neurotoxicity generation. In the present study, we selected rat pheochromocytoma (PC12) cells to investigate and compare the effects of two kinds of multiwall carbon nanotubes (MWCNTs) with different concentrations of Fe impurities which usually come from the massive production of CNTs by chemical vapor deposition. Exposure to Fe-high MWCNTs can reduce cell viability and increase cytoskeletal disruption of undifferentiated PC12 cells, diminish the ability to form mature neurites, and then adversely influence the neuronal dopaminergic phenotype in NGF-treated PC-12 cells. The present results highlight the critical role of iron residue in the adverse response to MWCNTs exposure in neural cells. These findings provide useful information for understanding the toxicity and safe application of carbon nanotubes.

  5. High-P,T Elasticity of Hcp Iron: Reinvestigation of the Applicability of Hcp Iron to the Earth's Inner Core

    Science.gov (United States)

    Tsuchiya, T.; Kawai, K.; Kuwayama, Y.; Ohsumi, M.; Ishii, M.

    2015-12-01

    Earth's inner core (329~364 GPa and 5000~6000 K) is thought to be composed of hexagonal closed pack (hcp) structured solid Fe-Ni alloy (e.g., Mao et al., 1998; Kuwayama et al., 2008; Sha & Cohen, 2010). Thermoelasticity of hcp (ɛ) iron is therefore a key to interpreting seismological information of the inner core: density, seismic wave velocities, and their anisotropy. However, several studies reported that hcp iron has a shear modulus distinctly larger than that of the inner core (e.g., Mao et al., 1998; Vocadlo et al., 2009). This large Poisson ratio of the inner core is one of the remaining inexplicable features of the deep Earth, and it suggests the presence of mechanisms to lower the S-wave velocity in the inner core, such as a low-velocity component (Prescher et al., 2015), pre-melting effect (Martorell et al., 2013), anelasticity, and so on. In this study, we perform ab initio molecular dynamics simulations employing a supercell larger than in previous calculations (Vocadlo et al., 2009; Martorell et al., 2013). Also computations are conducted in a wide P,T range including, but not limited to, the inner core conditions to clarify the P,T effects on the elasticity of the hcp iron more comprehensively, and to provide an internally-consistent thermoelastic model. In addition to checking the validity of the Birch's law, the obtained Poisson ratio and aggregate anisotropy, with and without the pre-melting effect, are compared against seismological constraints to reinvestigate the viability of hcp iron in the inner core. Research supported by KAKENHI (JSPS) and the X-ray Free Electron Laser Priority Strategy Program (MEXT).

  6. Steatohepatitis is developed by a diet high in fat, sucrose, and cholesterol without increasing iron concentration in rat liver.

    Science.gov (United States)

    Takai, Katsuko; Funaba, Masayuki; Matsui, Tohru

    2016-04-01

    Iron overload to the liver is known to be a pathogenesis of nonalcoholic steatohepatitis through oxidative stress. High-fat diets have been reported to increase iron concentration in livers that developed steatohepatitis in experimental animals. However, the effect of high-fat diets on hepatic iron concentration is controversial. We hypothesized that a diet high in lard, cholesterol, and sucrose (Western diet) leads to the development of steatohepatitis without increasing hepatic iron concentration. Rats were given either a control or the Western diet for 12 weeks. The Western diet increased triacylglycerol concentration and oxidative stress markers such as the concentration of thiobarbituric acid reactive substances and messenger RNA (mRNA) expression of heme oxygenase-1 in the liver. The Western diet also increased the mRNA expression of macrophage-1 antigen, cluster of differentiation (CD) 45, and CD68 in the liver, and nuclear factor κB level in liver nuclear fraction, suggesting the development of hepatic inflammation. Histological observation also indicated fatty liver and hepatic inflammation in the rats given the Western diet. In contrast, the Western diet decreased iron concentration in the liver. These results clearly indicated that the diet high in lard, cholesterol, and sucrose induces steatohepatitis without increasing hepatic iron concentration.

  7. Magnetoencephalography detection of high-frequency oscillations in the developing brain.

    Science.gov (United States)

    Leiken, Kimberly; Xiang, Jing; Zhang, Fawen; Shi, Jingping; Tang, Lu; Liu, Hongxing; Wang, Xiaoshan

    2014-01-01

    Increasing evidence from invasive intracranial recordings suggests that the matured brain generates both physiological and pathological high-frequency signals. The present study was designed to detect high-frequency brain signals in the developing brain using newly developed magnetoencephalography (MEG) methods. Twenty healthy children were studied with a high-sampling rate MEG system. Functional high-frequency brain signals were evoked by electrical stimulation applied to the index fingers. To determine if the high-frequency neuromagnetic signals are true brain responses in high-frequency range, we analyzed the MEG data using the conventional averaging as well as newly developed time-frequency analysis along with beamforming. The data of healthy children showed that very high-frequency brain signals (>1000 Hz) in the somatosensory cortex in the developing brain could be detected and localized using MEG. The amplitude of very high-frequency brain signals was significantly weaker than that of the low-frequency brain signals. Very high-frequency brain signals showed a much earlier latency than those of a low-frequency. Magnetic source imaging (MSI) revealed that a portion of the high-frequency signals was from the somatosensory cortex, another portion of the high-frequency signals was probably from the thalamus. Our results provide evidence that the developing brain generates high-frequency signals that can be detected with the non-invasive technique of MEG. MEG detection of high-frequency brain signals may open a new window for the study of developing brain function.

  8. Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters

    Energy Technology Data Exchange (ETDEWEB)

    Krachler, Regina, E-mail: regina.krachler@univie.ac.at [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Krachler, Rudolf F.; Wallner, Gabriele [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Steier, Peter [Isotope Research and Nuclear Physics, University of Vienna, Währingerstraße 17, 1090 Vienna (Austria); El Abiead, Yasin; Wiesinger, Hubert [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); Jirsa, Franz [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria); University of Johannesburg, Department of Zoology, P. O. Box 524, Auckland Park 2006 (South Africa); Keppler, Bernhard K. [Institute of Inorganic Chemistry, University of Vienna, Währingerstraße 42, 1090 Vienna (Austria)

    2016-06-15

    Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a {sup 59}Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16–24, 2014), the creeks that run through modified peatlands delivered 11–15 μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350–470 μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. - Highlights: • We report that peat-bogs are sources of bio-available iron to marine algae. • This iron is effectively chelated with aquatic humic acids. • The radiocarbon age of the iron-carrying aquatic humic acids was up to 550 years. • Analysis was focused on mixing experiments of iron-rich creek water with seawater. • Drained

  9. Detecting defect in cast iron using high-T{sub C} SQUID

    Energy Technology Data Exchange (ETDEWEB)

    He, D.F.; Yoshizawa, M.; Oyama, Y.; Nakamura, M

    2004-10-01

    For eddy-current NDE, due to the big permeability of ferromagnetic material, low testing frequency is needed to detect defects in it. SQUID has advantages in low frequency eddy current NDE. But the large magnetic field produced by ferromagnetic material often exceeds the dynamic range of general SQUID system. We developed a mobile high-T{sub C} SQUID system, with which, the dc and low-frequency magnetic field could be compensated well. Using our mobile SQUID system, the magnetic field produced by the cast iron could be compensated well and the defect in it could be successfully detected.

  10. Generation of drugs coated iron nanoparticles through high energy ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Radhika Devi, A.; Murty, B. S. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Chelvane, J. A. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Prabhakar, P. K.; Padma Priya, P. V.; Doble, Mukesh [Department of Biotechnology, Indian Institute of Technology Madras, Chennai 600036 (India)

    2014-03-28

    The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

  11. Calculation of High Frequency Complex Permeability of Carbonyl Iron Flakes in a Nomagnetic Matrix

    Institute of Scientific and Technical Information of China (English)

    WEN Fu-Sheng; QIAO Liang; YI Hai-Bo; ZHOU Dong; LI Fa-Shen

    2008-01-01

    The carbonyl iron flakes are fabricated by high-energy ball milling.The effective permeability is measured and calculated for the composite consisting of flakes embedded in a nonmagnetic matrix.The magnetic flakes with a shape anisotropy and random spatial distribution of normal direction are considered to calculate the complex permeability of magnetic flake materials.Its analytical model is derived from the Landau-Lifshitz- Gilbert equation and Bruggeman's effective medium theory.The calculated results agree well with the experiment.

  12. Centrifugal Casting of High Speed Steel/Nodular Cast Iron Compound Roll Collar

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The centrifugal casting of compound HSS/nodular cast iron roll collar was studied, and the factors affecting transition zone quality were analyzed. The pouring temperature and interval in pouring are the main factors affecting transition zone quality. By controlling process parameter and flux adding during casting, high quality roll collar was obtained. The cause, why in the casting of HSS part, segregation appears easily, was analyzed and the countermeasure eliminating segregation was put forward, the measure eliminating heat treatment crackling was also put forward.

  13. Feeding Against Gravity with Spot Feeders in High Silicon Ductile Iron

    DEFF Research Database (Denmark)

    Vedel-Smith, Nikolaj Kjelgaard; Tiedje, Niels Skat

    2014-01-01

    A test pattern, with three different moduli castings was developed to investigate methods to optimise feeding of high silicon ductile cast irons. Different feeder types, modulus, and locations were investigated using both an insulating and an exothermal sleeve material. Porosities were analysed......-hill against gravity. This effect may contribute to the thermal expansion created by the exothermal reaction. It was also found that the optimum feeder size does not scale linearly with the casting modulus but that larger casting modulus requires relatively smaller modulus feeders. The thermal gradient created...

  14. High-field proton MRS of human brain

    Energy Technology Data Exchange (ETDEWEB)

    Di Costanzo, Alfonso E-mail: alfonso.dicostanzo@unina2.it; Trojsi, F.; Tosetti, M.; Giannatempo, G.M.; Nemore, F.; Piccirillo, M.; Bonavita, S.; Tedeschi, G.; Scarabino, T

    2003-11-01

    Proton magnetic resonance spectroscopy ({sup 1}H-MRS) of the brain reveals specific biochemical information about cerebral metabolites, which may support clinical diagnoses and enhance the understanding of neurological disorders. The advantages of performing {sup 1}H-MRS at higher field strengths include better signal to noise ratio (SNR) and increased spectral, spatial and temporal resolution, allowing the acquisition of high quality, easily quantifiable spectra in acceptable imaging times. In addition to improved measurement precision of N-acetylaspartate, choline, creatine and myo-inositol, high-field systems allow the high-resolution measurement of other metabolites, such as glutamate, glutamine, {gamma}-aminobutyric acid, scyllo-inositol, aspartate, taurine, N-acetylaspartylglutamate, glucose and branched amino acids, thus extending the range of metabolic information. However, these advantages may be hampered by intrinsic field-dependent technical difficulties, such as decreased T2 signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, limitations in the design of homogeneous and sensitive radiofrequency (RF) coils, magnetic field instability and safety issues. Several studies demonstrated that these limitations could be overcome, suggesting that the appropriate optimization of high-field {sup 1}H-MRS would expand the application in the fields of clinical research and diagnostic routine.

  15. Role of the NMDA receptor and iron on free radical production and brain damage following transient middle cerebral artery occlusion.

    Science.gov (United States)

    Im, Doo Soon; Jeon, Jeong Wook; Lee, Jin Soo; Won, Seok Joon; Cho, Sung Ig; Lee, Yong Beom; Gwag, Byoung Joo

    2012-05-21

    Excess activation of ionotropic glutamate receptors and iron is believed to contribute to free radical production and neuronal death following hypoxic ischemia. We examined the possibility that both NMDA receptor activation and iron overload determine spatial and temporal patterns of free radical production after transient middle cerebral artery occlusion (tMCAO) in male Sprague-Dawley rats. Mitochondrial free radical (MFR) levels were maximally increased in neurons in the core at 1 h and 24 h after tMCAO. Early MFR production was blocked by administration of MK-801, an NMDA receptor antagonist, but not deferoxamine, an iron chelator. Neither MK-801 nor deferoxamine attenuated late MFR production in the core. Increased MFRs were observed in penumbral neurons within 6 h and gradually increased over 24 h after tMCAO. Slowly-evolving MFRs in the core and penumbra were accompanied by iron overload. Deferoxamine blocked iron overload but reduced MFR production only in the penumbra. Combined MK-801/deferoxamine reduced late MFR production in both core and penumbra in an additive manner. Combination therapy significantly ameliorated infarction compared with monotherapy. These findings suggest that the NMDA receptor activation and iron overload mediate late MFR production and infarction after tMCAO. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. A reliable and consistent production technology for high volume compacted graphite iron castings

    Institute of Scientific and Technical Information of China (English)

    Liu Jincheng

    2014-01-01

    The demands for improved engine performance, fuel economy, durability, and lower emissions provide a continual chalenge for engine designers. The use of Compacted Graphite Iron (CGI) has been established for successful high volume series production in the passenger vehicle, commercial vehicle and industrial power sectors over the last decade. The increased demand for CGI engine components provides new opportunities for the cast iron foundry industry to establish efficient and robust CGI volume production processes, in China and globaly. The production window range for stable CGI is narrow and constantly moving. Therefore, any one step single addition of magnesium aloy and the inoculant cannot ensure a reliable and consistent production process for complicated CGI engine castings. The present paper introduces the SinterCast thermal analysis process control system that provides for the consistent production of CGI with low nodularity and reduced porosity, without risking the formation of lfake graphite. The technology is currently being used in high volume Chinese foundry production. The Chinese foundry industry can develop complicated high demand CGI engine castings with the proper process control technology.

  17. A randomized cross over trial of tolerability and compliance of a micronutrient supplement with low iron separated from calcium vs high iron combined with calcium in pregnant women [ISRCTN56071145

    Directory of Open Access Journals (Sweden)

    Couturier Bernard

    2006-04-01

    Full Text Available Abstract Background Prenatal micronutrient combinations with high iron content are associated with high rates of gastrointestinal symptoms. This coupled with nausea and vomiting of pregnancy results in women often discontinuing their multivitamins. A new prescription supplement (PregVit® that separates iron from calcium in two tablets – morning and evening, has lower elemental iron content (35 mg, but results in similar extent of iron absorption when compared to another supplement containing (60 mg of elemental iron (Materna®. The objectives of this study were to compare tolerability and compliance with PregVit® vs. a supplement with high iron content (Materna®, in pregnant women. Methods Randomized, crossover open labeled study in 135 pregnant women attending outpatient clinics in Ontario and Quebec. Results Use of PregVit® was associated with a 30% reduction in constipation rate as compared to Materna®. Both products demonstrated similar compliance rates. Compliance of Materna® was negatively associated with the severity of nausea and vomiting of pregnancy. No such correlation was found for PregVvit®. Conclusion PregVit®, a supplement with lower iron content (35 mg, has significantly decreased constipation rates as compared to 60 mg iron- Materna and has similar compliance rates. High iron content in multivitamin supplements is associated with adverse effects in pregnancy.

  18. Preparation of carbon-encapsulated iron nanoparticles in high yield by DC arc discharge and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Cui, Lan; Lin, Kui [Center of Analysis, Tianjin University, Tianjin 300072 (China); Jin, Feng-min; Wang, Bin [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Shi, Shu-xiu [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Yang, De-an [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Hui [Center of Analysis, Tianjin University, Tianjin 300072 (China); He, Fei [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Chen, Xiao-ping [Center of Analysis, Tianjin University, Tianjin 300072 (China); Cui, Shen, E-mail: cuishen@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

    2013-03-15

    Highlights: ► CEINPs with core–shell structure and high Fe content were prepared in high yield by DC arc discharge. ► The anode II with a mass ratio of total iron to carbon 8:1 was used in DC arc discharge. ► The possible process of formation of CEINPs is briefly discussed. ► The uniformity of composition of anode is very important for the formation of CEINPs. ► The MEF and MMF of iron element may also play an important role in the formation of CEINPs. -- Abstract: Carbon-encapsulated iron nanoparticles (CEINPs) were prepared by DC arc discharge under nitrogen atmosphere of high temperature. The products were characterized by transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectroscope, and X-ray photoelectron spectroscope (XPS), and their magnetic properties were measured by physical property measurement system (PPMS). The product B{sub I}, obtained from the anode I, contains the nanoparticles of iron and iron carbide, and carbon coating with imperfect and disordered layer structure. The product B{sub II}, obtained from the anode II, mainly consists of CEINPs, whose cores mainly consist of iron and iron carbide and shells contain about 3–7 graphitic layers. The iron contents in the products B{sub I} and B{sub II} are 44.8 and 82.6 wt.%, respectively. The products B{sub I} and B{sub II} have similar phase composition which includes carbon, iron, iron carbide, ferrous and ferric oxide, iron nitride, and carbon nitride. The saturation magnetization (Ms) of the products B{sub I} and B{sub II} are 29.35 and 88.66 emu/g and their coercivity (Hc) are 220 and 240 Oe, respectively. The total yields of all the products formed in the arc discharge chamber from anodes I and II, except for the cylinder-shaped deposits formed on the top of the cathode, are 25.8 and 22.3 wt.%, respectively. The possible process of formation of CEINPs is briefly discussed on

  19. High-Tc superconducting quantum interference device recordings of spontaneous brain activity: Towards high-Tc magnetoencephalography

    Science.gov (United States)

    Öisjöen, F.; Schneiderman, J. F.; Figueras, G. A.; Chukharkin, M. L.; Kalabukhov, A.; Hedström, A.; Elam, M.; Winkler, D.

    2012-03-01

    We have performed single- and two-channel high transition temperature (high-Tc) superconducting quantum interference device (SQUID) magnetoencephalography (MEG) recordings of spontaneous brain activity in two healthy human subjects. We demonstrate modulation of two well-known brain rhythms: the occipital alpha rhythm and the mu rhythm found in the motor cortex. We further show that despite higher noise-levels compared to their low-Tc counterparts, high-Tc SQUIDs can be used to detect and record physiologically relevant brain rhythms with comparable signal-to-noise ratios. These results indicate the utility of high-Tc technology in MEG recordings of a broader range of brain activity.

  20. High Iron Stores in the Low Malaria Season Increase Malaria Risk in the High Transmission Season in a Prospective Cohort of Rural Zambian Children.

    Science.gov (United States)

    Barffour, Maxwell A; Schulze, Kerry J; Coles, Christian L; Chileshe, Justin; Kalungwana, Ng'andwe; Arguello, Margia; Siamusantu, Ward; Moss, William J; West, Keith P; Palmer, Amanda C

    2017-08-01

    Background: Higher iron stores, defined by serum ferritin (SF) concentration, may increase malaria risk.Objective: We evaluated the association between SF assessed during low malaria season and the risk of malaria during high malaria season, controlling for inflammation.Methods: Data for this prospective study were collected from children aged 4-8 y (n = 745) participating in a biofortified maize efficacy trial in rural Zambia. All malaria cases were treated at baseline (September 2012). We used baseline SF and malaria status indicated by positive microscopy at endline (March 2013) to define exposure and outcome, respectively. Iron status was defined as deficient (corrected or uncorrected SF iron status assessed in the low malaria seasons (baseline).Results: We observed an age-dependent, positive dose-response association between ferritin in the low malaria season and malaria incidence during the high malaria season in younger children. In children aged iron status [incidence rate ratio (IRR) with SF: 1.56; 95% CI: 0.64, 3.86; IRR with inflammation-corrected SF: 1.92; 95% CI: 0.75, 4.93] and high iron status (IRR with SF: 2.66; 95% CI: 1.10, 6.43; or IRR with corrected SF: 2.93; 95% CI: 1.17, 7.33) categories compared with the deficient iron status category. The relative increase in malaria risk for children with high iron status was statistically significant only among those with a concurrently normal serum soluble transferrin receptor concentration (Iron adequacy in 4- to 8-y-old children in rural Zambia was associated with increased malaria risk. Our findings underscore the need to integrate iron interventions with malaria control programs. This trial was registered at clinicaltrials.gov as NCT01695148. © 2017 American Society for Nutrition.

  1. Absence of an orphan mitochondrial protein, c19orf12, causes a distinct clinical subtype of neurodegeneration with brain iron accumulation.

    Science.gov (United States)

    Hartig, Monika B; Iuso, Arcangela; Haack, Tobias; Kmiec, Tomasz; Jurkiewicz, Elzbieta; Heim, Katharina; Roeber, Sigrun; Tarabin, Victoria; Dusi, Sabrina; Krajewska-Walasek, Malgorzata; Jozwiak, Sergiusz; Hempel, Maja; Winkelmann, Juliane; Elstner, Matthias; Oexle, Konrad; Klopstock, Thomas; Mueller-Felber, Wolfgang; Gasser, Thomas; Trenkwalder, Claudia; Tiranti, Valeria; Kretzschmar, Hans; Schmitz, Gerd; Strom, Tim M; Meitinger, Thomas; Prokisch, Holger

    2011-10-07

    The disease classification neurodegeneration with brain iron accumulation (NBIA) comprises a clinically and genetically heterogeneous group of progressive neurodegenerative disorders characterized by brain iron deposits in the basal ganglia. For about half of the cases, the molecular basis is currently unknown. We used homozygosity mapping followed by candidate gene sequencing to identify a homozygous 11 bp deletion in the orphan gene C19orf12. Mutation screening of 23 ideopathic NBIA index cases revealed two mutated alleles in 18 of them, and one loss-of-function mutation is the most prevalent. We also identified compound heterozygous missense mutations in a case initially diagnosed with Parkinson disease at age 49. Psychiatric signs, optic atrophy, and motor axonal neuropathy were common findings. Compared to the most prevalent NBIA subtype, pantothenate kinase associated neurodegeneration (PKAN), individuals with two C19orf12 mutations were older at age of onset and the disease progressed more slowly. A polyclonal antibody against the predicted membrane spanning protein showed a mitochondrial localization. A histopathological examination in a single autopsy case detected Lewy bodies, tangles, spheroids, and tau pathology. The mitochondrial localization together with the immunohistopathological findings suggests a pathomechanistic overlap with common forms of neurodegenerative disorders.

  2. Process for making a high toughness-high strength iron alloy

    Science.gov (United States)

    Stephens, J. R.; Witzke, W. R. (Inventor)

    1979-01-01

    A steel alloy is produced by a process which includes using cold rolling at room temperature and subsequent heat treatment at temperatures ranging from 500 C to 650 C. The resulting alloys exhibits excellent strength and toughness characteristics at cryogenic temperatures. This alloy consists essentially of about 10 to 16 percent by weight nickel, to about 1.0 percent by weight aluminum, and 0 to about 3 percent by weight of at least one of the following additional elements: copper, lanthanum, niobium, tantalum, titanium, vanadium, yttrium, zirconium and the rare earth metals, with the balance being essentially iron. The improved alloy possesses a fracture toughness ranging from 200 to 230 ksi sq in. and yield strengths up to 230 ksi.

  3. Effect of Different Inoculants on Impact Toughness in High Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Siekaniec D.

    2017-06-01

    Full Text Available The present work, presented the study of effect of different inoculants on impact toughness in High Chromium Cast Iron. The molds were pouring in industrial conditions and samples were tested in laboratory in Faculty of Foundry Engineering at AGH. Seven samples were tested - one reference sample, three with different addition of Fe-Ti, and three with different addition of Al. The samples were subjected to impact toughness on Charpy hammer and the hardness test. The presented investigations indicate that for the each inoculant there is an optimal addition at which the sample obtained the highest value of impact toughness. For the Fe-Ti it is 0.66% and for Al is 0.17%. Of all the examined inoculants best results were obtained at a dose of 0.66% Fe-Ti. Titanium is a well-known as a good modifier but very interesting results gives the aluminum. Comparing the results obtained for the Fe-Ti and Al can be seen that in the case of aluminum hardness is more stable. The hardness of all samples is around 40-45 HRC, which is not high for this type of cast iron. Therefore, in future studies it is planned to carry out the heat treatment procedure that may improves hardness.

  4. High-performing mesoporous iron oxalate anodes for lithium-ion batteries.

    Science.gov (United States)

    Ang, Wei An; Gupta, Nutan; Prasanth, Raghavan; Madhavi, Srinivasan

    2012-12-01

    Mesoporous iron oxalate (FeC(2)O(4)) with two distinct morphologies, i.e., cocoon and rod, has been synthesized via a simple, scalable chimie douce precipitation method. The solvent plays a key role in determining the morphology and microstructure of iron oxalate, which are studied by field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Crystallographic characterization of the materials has been carried out by X-ray diffraction and confirmed phase-pure FeC(2)O(4)·2H(2)O formation. The critical dehydration process of FeC(2)O(4)·2H(2)O resulted in anhydrous FeC(2)O(4), and its thermal properties are studied by thermogravimetric analysis. The electrochemical properties of anhydrous FeC(2)O(4) in Li/FeC(2)O(4) cells are evaluated by cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. The studies showed that the initial discharge capacities of anhydrous FeC(2)O(4) cocoons and rods are 1288 and 1326 mA h g(-1), respectively, at 1C rate. Anhydrous FeC(2)O(4) cocoons exhibited stable capacity even at high C rates (11C). The electrochemical performance of anhydrous FeC(2)O(4) is found to be greatly influenced by the number of accessible reaction sites, morphology, and size effects.

  5. High-temperature oxidation/sulfidation resistance of iron-aluminide coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.; Wright, I.G.; Goodwin, G.M.; Howell, M.

    1996-04-01

    Iron aluminides containing > 20-25 at. % Al have oxidation and sulfidation resistance at temperatures well above those at which these alloys have adequate mechanical strength. Accordingly, these alloys may find application as coatings or claddings on more conventional higher-strength materials which are generally less corrosion-resistant at high temperatures. To this end, iron-aluminide coatings were prepared by gas tungsten arc and gas metal arc weld-overlay techniques. Specimens were cut from weld deposits and exposed to a highly aggressive oxidizing-sulfidizing (H2S-H2-H2O-Ar) environment at 800 C. All the weld overlayers showed good corrosion behavior under isothermal conditions, including a gas metal arc-produced deposit with only 21 at. % Al. Rapid degradation in corrosion resistance was observed under thermal cycling conditions when the initally grown scales spalled and the rate of reaction was then not controlled by formation of slowly growing Al oxide. Higher starting Al concentrations (> {approximately} 25 at. %) are needed to assure overall oxidation-sulfidation resistance of the weld overlays, but hydrogen cracking susceptibility must be minimized in order to physically separate the corrosive species from the reactive substrate material.

  6. Preparation of Highly Pure Vanadyl Sulfate from Sulfate Solutions Containing Impurities of Iron and Aluminum by Solvent Extraction Using EHEHPA

    Directory of Open Access Journals (Sweden)

    Dan Li

    2017-03-01

    Full Text Available The preparation of highly pure vanadyl sulfate from sulfate solutions containing impurities of iron and aluminumwas investigated by solvent extraction with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (EHEHPA and tri-n-butyl phosphate (TBP as the phase modifier. The extraction and stripping conditions of vanadium (IV and its separation from iron and aluminum were optimized. Under the optimal extraction conditions, the extraction of vanadium (IV and iron were 68% and 53%, respectively, while only 2% aluminum was extracted in a single contact, suggesting good separation of vanadium (IV from aluminum. Sulfuric acid solution was used for the stripping. Nearly 100% vanadium (IV and 95% aluminum were stripped, while only 10% iron was stripped under the optimal stripping conditions in a single contact, suggesting good separation of vanadium (IV from iron. After five stages of extraction and stripping, highly pure vanadyl sulfate containing 76.5 g/L V (IV with the impurities of 12 mg/L Fe and 10 mg/L Al was obtained, which is suitable for the electrolyte of a vanadium redox flow battery. Organic solution was well regenerated after stripping by oxalic acid solution to remove the remaining iron. The mechanism of vanadium (IV extraction using EHEHPA was also discussed based on the Fourier transform infrared spectroscopy (FT-IR analysis.

  7. Nitrogen removal efficiency of iron-carbon micro-electrolysis system treating high nitrate nitrogen organic pharmaceutical wastewater

    Institute of Scientific and Technical Information of China (English)

    周健; 段送华; 陈垚; 胡斌

    2009-01-01

    The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.

  8. The role of equilibrium volume and magnetism on the stability of iron phases at high pressures.

    Science.gov (United States)

    Alnemrat, S; Hooper, J P; Vasiliev, I; Kiefer, B

    2014-01-29

    The present study provides new insights into the pressure dependence of magnetism by tracking the hybridization between crystal orbitals for pressures up to 600 GPa in the known hcp, bcc and fcc iron. The Birch-Murnaghan equation of state parameters are; bcc: V0 = 11.759 A(3)/atom, K0 = 177.72 GPa; hcp: V0 = 10.525 A(3)/atom, K0 = 295.16 GPa; and fcc: V0 = 10.682 A(3)/atom, K0 = 274.57 GPa. These parameters compare favorably with previous studies. Consistent with previous studies we find that the close-packed hcp and fcc phases are non-magnetic at pressures above 50 GPa and 60 GPa, respectively. The principal features of magnetism in iron are predicted to be invariant, at least up to ∼6% overextension of the equilibrium volume. Our results predict that magnetism for overextended fcc iron disappears via an intermediate spin state. This feature suggests that overextended lattices can be used to stabilize particular magnetic states. The analysis of the orbital hybridization shows that the magnetic bcc structure at high pressures is stabilized by splitting the majority and minority spin bands. The bcc phase is found to be magnetic at least up to 600 GPa; however, magnetism is insufficient to stabilize the bcc phase itself, at least at low temperatures. Finally, the analysis of the orbital contributions to the total energy provides evidence that non-magnetic hcp and fcc phases are likely more stable than bcc at core earth pressures.

  9. High-intensity ultrasonication as a way to prepare graphene/amorphous iron oxyhydroxide hybrid electrode with high capacity in lithium battery.

    Science.gov (United States)

    González, José R; Menéndez, Rosa; Alcántara, Ricardo; Nacimiento, Francisco; Tirado, José L; Zhecheva, Ekaterina; Stoyanova, Radostina

    2015-05-01

    The preparation of graphene/iron oxyhydroxide hybrid electrode material with very homogeneous distribution and close contact of graphene and amorphous iron oxyhydroxide nanoparticles has been achieved by using high-intensity ultrasonication. Due to the negative charge of the graphene surface, iron ions are attracted toward the surface of dispersed graphene, according to the zeta potential measurements. The anchoring of the FeO(OH) particles to the graphene layers has been revealed by using mainly TEM, XPS and EPR. TEM observations show that the size of the iron oxide particles is about 4 nm. The ultrasonication treatment is the key parameter to achieve small particle size in these graphene/iron oxyhydroxide hybrid materials. The electrochemical behavior of composite graphene/amorphous iron oxyhydroxide prepared by using high-intensity ultrasonication is outstanding in terms of gravimetric capacity and cycling stability, particularly when metallic foam is used as both the substrate and current collector. The XRD-amorphous character of iron oxyhydroxide in the hybrid electrode material and the small particle size contribute to achieve the improved electrochemical performance.

  10. Linking Brain Principles to High-Quality Early Childhood Education

    Science.gov (United States)

    Rushton, Stephen; Juola-Rushton, Anne

    2011-01-01

    Many educators are already knowledgeable about and skilled in best practices. And much of what is happening in developmentally appropriate programs exemplifies "brain compatible" practices. Being educated in the connections between best practices and brain compatibility is an important part of the knowledge base of early childhood educators. Just…

  11. Optimization of synthesis and peptization steps to obtain iron oxide nanoparticles with high energy dissipation rates

    Energy Technology Data Exchange (ETDEWEB)

    Mérida, Fernando [Deparment of Chemical Engineering, University of Puerto Rico, Mayagüez, P.O. Box 9046, Mayagüez, PR 00680 (United States); Chiu-Lam, Andreina [Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 32611-6005 (United States); Bohórquez, Ana C. [J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, P.O. Box 116131, Gainesville, FL 32611-6131 (United States); Maldonado-Camargo, Lorena [Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 32611-6005 (United States); Pérez, María-Eglée; Pericchi, Luis [Department of Mathematics, University of Puerto Rico, Río Piedras, P.O. Box 70377, San Juan, PR 00936-8377 (United States); Torres-Lugo, Madeline [Deparment of Chemical Engineering, University of Puerto Rico, Mayagüez, P.O. Box 9046, Mayagüez, PR 00680 (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Florida, P.O. Box 116005, Gainesville, FL 32611-6005 (United States); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, P.O. Box 116131, Gainesville, FL 32611-6131 (United States)

    2015-11-15

    Magnetic Fluid Hyperthermia (MFH) uses heat generated by magnetic nanoparticles exposed to alternating magnetic fields to cause a temperature increase in tumors to the hyperthermia range (43–47 °C), inducing apoptotic cancer cell death. As with all cancer nanomedicines, one of the most significant challenges with MFH is achieving high nanoparticle accumulation at the tumor site. This motivates development of synthesis strategies that maximize the rate of energy dissipation of iron oxide magnetic nanoparticles, preferable due to their intrinsic biocompatibility. This has led to development of synthesis strategies that, although attractive from the point of view of chemical elegance, may not be suitable for scale-up to quantities necessary for clinical use. On the other hand, to date the aqueous co-precipitation synthesis, which readily yields gram quantities of nanoparticles, has only been reported to yield sufficiently high specific absorption rates after laborious size selective fractionation. This work focuses on improvements to the aqueous co-precipitation of iron oxide nanoparticles to increase the specific absorption rate (SAR), by optimizing synthesis conditions and the subsequent peptization step. Heating efficiencies up to 1048 W/g{sub Fe} (36.5 kA/m, 341 kHz; ILP=2.3 nH m{sup 2} kg{sup −1}) were obtained, which represent one of the highest values reported for iron oxide particles synthesized by co-precipitation without size-selective fractionation. Furthermore, particles reached SAR values of up to 719 W/g{sub Fe} (36.5 kA/m, 341 kHz; ILP=1.6 nH m{sup 2} kg{sup −1}) when in a solid matrix, demonstrating they were capable of significant rates of energy dissipation even when restricted from physical rotation. Reduction in energy dissipation rate due to immobilization has been identified as an obstacle to clinical translation of MFH. Hence, particles obtained with the conditions reported here have great potential for application in nanoscale thermal

  12. Study of high cycle fatigue of PVD surface-modified austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Feng, H.P.; Lee, S.C.; Hsu, C.H.; Ho, J.M. [Tatung Inst. of Technol., Taipei (Taiwan, Province of China). Dept. of Mater. Eng.

    1999-05-25

    Austempered ductile iron (ADI) is made from ductile iron by an austempering treatment, and its main microstructure is ausferrite that is composed of acicular ferrite and high carbon austenite. The purpose of this experiment is to investigate the influence of different coating layers and the size of casting (mass effect) on the high-cycle fatigue properties of ADI. Specimens in two casting sizes of the same chemical composition were subjected to a high-toughness austempering treatment, then coated with TiN or TiCN hard films by a physical vapor deposition (PVD) process. The results showed that the fatigue limit of the small casting size ADI is 292 MPa for ADI coated with TiN and 306 MPa for ADI coated with TiCN, which are 16% and 22%, respectively, higher than that of the ADI without coating (251 MPa). For the large casting size ADI, the fatigue limits are 200, 214 and 217 MPa for ADI without coating, ADI coated with TiN and ADI coated with TiCN, respectively. ADI coated with TiN and with TiCN are 7% and 9% better than the uncoated. Thus, it is concluded that TiN and TiCN coatings by PVD can improve the high-cycle fatigue strength of ADI. This is due to the high surface hardness and possibly the ADI surface compressive residual stress as well. For the small casting size ADI, TiCN-coated specimens have a bit higher fatigue strengths and this might be attributed to the higher hardness of TiCN than TiN films. As to the effect of mass, it is found that the small casting size has better fatigue properties and benefits more from the coating films. This could have stemmed from the higher nodule count and its associated benefits in thinner castings. (orig.) 24 refs.

  13. Enabling iron pyrite (FeS2) and related ternary pyrite compounds for high-performance solar energy applications

    Science.gov (United States)

    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

  14. Iron deficiency in childhood

    NARCIS (Netherlands)

    Uijterschout, L.

    2015-01-01

    Iron deficiency (ID) is the most common micronutrient deficiency in the world. Iron is involved in oxygen transport, energy metabolism, immune response, and plays an important role in brain development. In infancy, ID is associated with adverse effects on cognitive, motor, and behavioral development

  15. Iron deficiency in childhood

    NARCIS (Netherlands)

    Uijterschout, L.

    2015-01-01

    Iron deficiency (ID) is the most common micronutrient deficiency in the world. Iron is involved in oxygen transport, energy metabolism, immune response, and plays an important role in brain development. In infancy, ID is associated with adverse effects on cognitive, motor, and behavioral development

  16. High spin-filter efficiency and Seebeck effect through spin-crossover iron-benzene complex

    Science.gov (United States)

    Yan, Qiang; Zhou, Liping; Cheng, Jue-Fei; Wen, Zhongqian; Han, Qin; Wang, Xue-Feng

    2016-04-01

    Electronic structures and coherent quantum transport properties are explored for spin-crossover molecule iron-benzene Fe(Bz)2 using density functional theory combined with non-equilibrium Green's function. High- and low-spin states are investigated for two different lead-molecule junctions. It is found that the asymmetrical T-shaped contact junction in the high-spin state behaves as an efficient spin filter while it has a smaller conductivity than that in the low-spin state. Large spin Seebeck effect is also observed in asymmetrical T-shaped junction. Spin-polarized properties are absent in the symmetrical H-shaped junction. These findings strongly suggest that both the electronic and contact configurations play significant roles in molecular devices and metal-benzene complexes are promising materials for spintronics and thermo-spintronics.

  17. High-throughput syntheses of iron phosphite open frameworks in ionic liquids

    Science.gov (United States)

    Wang, Zhixiu; Mu, Ying; Wang, Yilin; Bing, Qiming; Su, Tan; Liu, Jingyao

    2017-02-01

    Three open-framework iron phosphites: Feп5(NH4)2(HPO3)6 (1), Feп2Fe♯(NH4)(HPO3)4 (2) and Fe♯2(HPO3)3 (3) have been synthesized under ionothermal conditions. How the different synthesis parameters, such as the gel concentrations, synthetic times, reaction temperatures and solvents affect the products have been monitored by using high-throughput approaches. Within each type of experiment, relevant products have been investigated. The optimal reaction conditions are obtained from a series of experiments by high-throughput approaches. All the structures are determined by single-crystal X-ray diffraction analysis and further characterized by PXRD, TGA and FTIR analyses. Magnetic study reveals that those three compounds show interesting magnetic behavior at low temperature.

  18. Highly siderophile elements were stripped from Earth's mantle by iron sulfide segregation

    CERN Document Server

    Rubie, David C; Jacobson, Seth A; Morbidelli, Alessandro; Palme, Herbert; Vogel, Antje K; Frost, Daniel J

    2016-01-01

    Highly siderophile elements (HSEs) are strongly depleted in the bulk silicate Earth (BSE) but are present in near-chondritic relative abundances. The conventional explanation is that the HSEs were stripped from the mantle by the segregation of metal during core formation but were added back in near-chondritic proportions by late accretion, after core formation had ceased. Here we show that metal-silicate equilibration and segregation during Earth's core formation actually increased HSE mantle concentrations because HSE partition coefficients are relatively low at the high pressures of core formation within Earth. The pervasive exsolution and segregation of iron sulfide liquid from silicate liquid (the "Hadean matte") stripped magma oceans of HSEs during cooling and crystallization, before late accretion, and resulted in slightly suprachondritic palladium/iridium and ruthenium/iridium ratios.

  19. Highly magnetic iron carbide nanoparticles as effective T(2) contrast agents.

    Science.gov (United States)

    Huang, Guoming; Hu, Juan; Zhang, Hui; Zhou, Zijian; Chi, Xiaoqin; Gao, Jinhao

    2014-01-21

    This paper reports that iron carbide nanoparticles with high air-stability and strong saturation magnetization can serve as effective T2 contrast agents for magnetic resonance imaging. Fe5C2 nanoparticles (~20 nm in diameter) exhibit strong contrast enhancement with an r2 value of 283.2 mM(-1) S(-1), which is about twice as high as that of spherical Fe3O4 nanoparticles (~140.9 mM(-1) S(-1)). In vivo experiments demonstrate that Fe5C2 nanoparticles are able to produce much more significant MRI contrast enhancement than conventional Fe3O4 nanoparticles in living subjects, which holds great promise in biomedical applications.

  20. Highly siderophile elements were stripped from Earth’s mantle by iron sulfide segregation

    Science.gov (United States)

    Rubie, David C.; Laurenz, Vera; Jacobson, Seth A.; Morbidelli, Alessandro; Palme, Herbert; Vogel, Antje K.; Frost, Daniel J.

    2016-09-01

    Highly siderophile elements (HSEs) are strongly depleted in the bulk silicate Earth (BSE) but are present in near-chondritic relative abundances. The conventional explanation is that the HSEs were stripped from the mantle by the segregation of metal during core formation but were added back in near-chondritic proportions by late accretion, after core formation had ceased. Here we show that metal-silicate equilibration and segregation during Earth’s core formation actually increased HSE mantle concentrations because HSE partition coefficients are relatively low at the high pressures of core formation within Earth. The pervasive exsolution and segregation of iron sulfide liquid from silicate liquid (the “Hadean matte”) stripped magma oceans of HSEs during cooling and crystallization, before late accretion, and resulted in slightly suprachondritic palladium/iridium and ruthenium/iridium ratios.

  1. Enhanced high-solids anaerobic digestion of waste activated sludge by the addition of scrap iron.

    Science.gov (United States)

    Zhang, Yaobin; Feng, Yinghong; Yu, Qilin; Xu, Zibin; Quan, Xie

    2014-05-01

    Anaerobic digestion of waste activated sludge usually requires pretreatment procedure to improve the bioavailability of sludge, which involves considerable energy and high expenditures. This study proposes a cost-effective method for enhanced anaerobic digestion of sludge without a pretreatment by directly adding iron into the digester. The results showed that addition of Fe(0) powder could enhance 14.46% methane yield, and Fe scrap (clean scrap) could further enhance methane yield (improving rate 21.28%) because the scrap has better mass transfer efficiency with sludge and liquid than Fe(0) powder. The scrap of Fe with rust (rusty scrap) could induce microbial Fe(III) reduction, which resulted in achieving the highest methane yield (improving rate 29.51%), and the reduction rate of volatile suspended solids (VSS) was also highest (48.27%) among Fe powder, clean scrap and rusty scrap. PCR-DGGE proved that the addition of rusty scrap could enhance diversity of acetobacteria and enrich iron-reducing bacteria to enhance degradation of complex substrates.

  2. Reduction of highly concentrated phosphate from aqueous solution using pectin-nanoscale zerovalent iron (PNZVI).

    Science.gov (United States)

    Wang, Hongyu; Zou, Zhuocheng; Xiao, Xuelian; Chen, Dan; Yang, Kai

    2016-01-01

    Pectin-nanoscale zerovalent iron (PNZVI) has been studied as an effective phosphate adsorption material to remove highly concentrated phosphate from aqueous solution. Batch phosphate removal and equilibrium experiments were conducted in order to evaluate the effects of environmental factors such as pH, coexisting anions and ionic strengths on phosphate removal by PNZVI. The scanning electron microscope images of nanoscale zerovalent iron (NZVI) and PNZVI demonstrated that PNZVI exhibited larger specific surface areas than NZVI so that PNZVI had higher phosphate removal efficiency than NZVI. Equilibrium experiments showed that phosphate adsorption by PNZVI was well fitted with the Freundlich and Langmuir models. In addition, the maximum adsorption capacity reached 277.38 mgP/gPNZVI. The ionic strengths and common anions showed no significant effects on the process of phosphate adsorption by PNZVI. The phosphate removal efficiency increased to a peak value with pH increased from 2.0 to 5.0, then decreased with pH further increased from 5.0 to 10.0. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses of PNZVI and P-loaded PNZVI indicated that adsorption, rather than redox reaction, was the dominant mechanism for the removal of phosphate by PNZVI.

  3. High-carbon fly-ash as a binder for iron ore pellets

    Energy Technology Data Exchange (ETDEWEB)

    Kawatra, S.K.; Eisele, T.C.; Ripke, S.J.; Ramirez, G.

    1999-09-01

    The goal of this project was to convert currently unusable fly-ashes into a material that can be used as a binder for iron ore. Such a binder would also be useful for other high-volume markets, including foundry sand mold binders. Previously, the investigators used fly-ash in combination with calcium hydroxide as an additive while calcium chloride was added as a hardening accelerator. However, the addition of chloride salts have a detrimental effect because chlorine causes corrosion in processing equipment. Therefore, other potential hardening accelerators were investigated during this project. During production, dried iron-ore pellets are required to have crushing strength of at least 22.2 newtons (5 pounds force) per 12.7 mm (1/2 inch) diameter pellet. The pellets are then sintered at temperatures up to 1300 C and must not exhibit a significant degree of spalling or cracking. Pellets will therefore be tested to determine whether acceptable dry crushing strengths can be achieved.

  4. Transmission electron microscopy study of high temperature bainitic transformation in 1 wt.% Mn ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadabadi, M.N. [Tohoku Univ., Sendai (Japan); Niyama, E. [Tohoku Univ., Sendai (Japan); Echigoya, J. [Tohoku Univ., Sendai (Japan)

    1995-04-01

    A 1 wt.% Mn ductile iron austenitized at 900 C for 90 min and austempered at 375 C for different periods was used to study some aspects of bainitic reaction in high Mn austempered ductile iron with reference to carbide precipitation in bainitic ferrite. Transmission electron microscopy (TEM) energy-dispersive X-ray analysis (EDXA) study shows that precipitation of carbide in the ferritic component of bainite is a function of the local concentration of alloying elements. In other words, in the region near graphite where Si segregates and there is negative Mn segregation as well as carbon, the bainitic ferrite is carbide free. However, in the intercellular region where Mn segregates and Si is depleted, the ferritic component of bainite occurs together with very fine and almost uniformly distributed carbide. Furthermore, TEM-EDXA results show that the increase in Mn content not only delays stage I (the initial transformation of austenite to ferrite and retained austenite) of the bainitic reaction, but also delays stage II (decomposition of retained austenite to ferrite and carbide). ((orig.))

  5. Synthesis, characterization, and in vitro biological evaluation of highly stable diversely functionalized superparamagnetic iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Dipsikha; Sahu, Sumanta K. [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Banerjee, Indranil [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Das, Manasmita [Indian Institute of Technology Kharagpur, Department of Chemistry (India); Mishra, Debashish; Maiti, Tapas K. [Indian Institute of Technology Kharagpur, Department of Biotechnology (India); Pramanik, Panchanan, E-mail: dipsikha.chem@gmail.com [Indian Institute of Technology Kharagpur, Department of Chemistry (India)

    2011-09-15

    In this article, we report the design and synthesis of a series of well-dispersed superparamagnetic iron oxide nanoparticles (SPIONs) using chitosan as a surface modifying agent to develop a potential T{sub 2} contrast probe for magnetic resonance imaging (MRI). The amine, carboxyl, hydroxyl, and thiol functionalities were introduced on chitosan-coated magnetic probe via simple reactions with small reactive organic molecules to afford a series of biofunctionalized nanoparticles. Physico-chemical characterizations of these functionalized nanoparticles were performed by TEM, XRD, DLS, FTIR, and VSM. The colloidal stability of these functionalized iron oxide nanoparticles was investigated in presence of phosphate buffer saline, high salt concentrations and different cell media for 1 week. MRI analysis of human cervical carcinoma (HeLa) cell lines treated with nanoparticles elucidated that the amine-functionalized nanoparticles exhibited higher amount of signal darkening and lower T{sub 2} relaxation in comparison to the others. The cellular internalization efficacy of these functionalized SPIONs was also investigated with HeLa cancer cell line by magnetically activated cell sorting (MACS) and fluorescence microscopy and results established selectively higher internalization efficacy of amine-functionalized nanoparticles to cancer cells. These positive attributes demonstrated that these nanoconjugates can be used as a promising platform for further in vitro and in vivo biological evaluations.

  6. Ethylene diamine-assisted synthesis of iron oxide nanoparticles in high-boiling polyolys.

    Science.gov (United States)

    Arndt, Darius; Zielasek, Volkmar; Dreher, Wolfgang; Bäumer, Marcus

    2014-03-01

    The decomposition of iron(III) acetylacetonate in high-boiling polyols such as diethylene glycole is an efficient way to produce water-soluble iron oxide nanoparticles (IONPs) with small sizes. We present an extension of this method by introducing ethylene diamine (EDA) or diethylene triamine (DTA) as a structure-directing agent and adding polyvinylpyrrolidone (PVP) as a stabilizing agent. The synthesis was studied with respect to effects of the chain length of the polyol used as solvent, the chain length of the structure-directing agent, the presence of PVP, the heating rate, and the nature of the precursor. By varying these parameters, we were able to show, that probably an interplay of the structure-directing agent and the polyol plays an important role for the stabilization and growth of the different facets of the IONP crystal. The chain length of the polyol used as solvent alters the influence of EDA or DTA as stabilizer of {111} facets, leading to IONPs with spherical, tetrahedral, or nanoplate morphology and mean diameters ranging from 4 nm up to 25 nm. PVP in the reaction medium narrows down particle size and shape distributions and promotes the formation of very stable, water-based colloidal solutions. The saturation magnetization of the particles was determined by a superconducting quantum interference device (SQUID) and their ability to act as a T2-contrast agent was tested by magnetic resonance imaging (MRI). Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters.

    Science.gov (United States)

    Krachler, Regina; Krachler, Rudolf F; Wallner, Gabriele; Steier, Peter; El Abiead, Yasin; Wiesinger, Hubert; Jirsa, Franz; Keppler, Bernhard K

    2016-06-15

    Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a (59)Fe radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16-24, 2014), the creeks that run through modified peatlands delivered 11-15μg iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350-470μg iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands.

  8. High-precision determination of the isotopic composition of dissolved iron in iron depleted seawater by double spike multicollector-ICPMS.

    Science.gov (United States)

    Lacan, Francois; Radic, Amandine; Labatut, Marie; Jeandel, Catherine; Poitrasson, Franck; Sarthou, Geraldine; Pradoux, Catherine; Chmeleff, Jerome; Freydier, Remi

    2010-09-01

    This work demonstrates the feasibility of the measurement of the isotopic composition of dissolved iron in seawater for an iron concentration range, 0.05-1 nmol L(-1), allowing measurements in most oceanic waters, including Fe depleted waters of high nutrient low chlorophyll areas. It presents a detailed description of our previously published protocol, with significant improvements on detection limit and blank contribution. Iron is preconcentrated using a nitriloacetic acid superflow resin and purified using an AG 1-x4 anion exchange resin. The isotopic ratios are measured with a multicollector-inductively coupled plasma mass spectrometer (MC-ICPMS) Neptune, coupled with a desolvator (Aridus II or Apex-Q), using a (57)Fe-(58)Fe double spike mass bias correction. A Monte Carlo test shows that optimum precision is obtained for a double spike composed of approximately 50% (57)Fe and 50% (58)Fe and a sample to double spike quantity ratio of approximately 1. Total procedural yield is 91 +/- 25% (2SD, n = 55) for sample sizes from 20 to 2 L. The procedural blank ranges from 1.4 to 1.1 ng, for sample sizes ranging from 20 to 2 L, respectively, which, converted into Fe concentrations, corresponds to blank contributions of 0.001 and 0.010 nmol L(-1), respectively. Measurement precision determined from replicate measurements of seawater samples and standard solutions is 0.08 per thousand (delta(56)Fe, 2SD). The precision is sufficient to clearly detect and quantify isotopic variations in the oceans, which so far have been observed to span 2.5 per thousand and thus opens new perspectives to elucidate the oceanic iron cycle.

  9. High pressure structures of "111" type iron-based superconductors predicted from first-principles.

    Science.gov (United States)

    Zhang, Xinxin; Wang, Yanchao; Ma, Yanming

    2012-11-21

    The high-pressure crystal structures of the "111" type iron-based superconductors: NaFeAs, LiFeP and LiFeAs have been systematically explored by using particle-swarm structural searches. It was found that though these iron-based superconductors are chemically similar, they adopted distinct structural phase transitions: P4/nmm→Cmcm→P3m1 for NaFeAs, P4/nmm→Cmcm→I4mm for LiFeP, and P4/nmm→P3m1 →I4mm→P6(3)/mmc for LiFeAs under high pressure. The high pressure orthorhombic Cmcm phase preserved the structural features of FeX(4)(X = As, P) tetrahedral layers present in the ambient-pressure P4/nmm structure. However, the FeX(4) tetrahedrons in the Cmcm phase were clearly distorted, leading to changes in the electronic behavior around the Fermi level. Under higher pressures, the FeX(4) layered structural features were no longer persistent and three-dimensional crystal structures were stabilized in other P3m1, I4mm, and P6(3)/mmc phases, which featured FeAs(5)/FeAs(6) hexahedron and octahedrons, FeX(5) tetragonal pyramids, and FeAs(6) octahedrons, respectively. Analysis of the electronic density of states suggests that most of the high pressure phases are metallic except for the tetragonal I4mm phase, which possesses a narrow band gap. This semiconducting state might relate to the tetragonal pyramid structure formed by FeX(5) unit, which might be favorable for charge localization.

  10. Measuring brain manganese and iron accumulation in rats following 14 weeks of low-dose manganese treatment using atomic absorption spectroscopy and magnetic resonance imaging.

    Science.gov (United States)

    Fitsanakis, Vanessa A; Zhang, Na; Anderson, Joel G; Erikson, Keith M; Avison, Malcolm J; Gore, John C; Aschner, Michael

    2008-05-01

    Chronic exposure to manganese (Mn) may lead to a movement disorder due to preferential Mn accumulation in the globus pallidus and other basal ganglia nuclei. Iron (Fe) deficiency also results in increased brain Mn levels, as well as dysregulation of other trace metals. The relationship between Mn and Fe transport has been attributed to the fact that both metals can be transported via the same molecular mechanisms. It is not known, however, whether brain Mn distribution patterns due to increased Mn exposure vs. Fe deficiency are the same, or whether Fe supplementation would reverse or inhibit Mn deposition. To address these questions, we utilized four distinct experimental populations. Three separate groups of male Sprague-Dawley rats on different diets (control diet [MnT], Fe deficient [FeD], or Fe supplemented [FeS]) were given weekly intravenous Mn injections (3 mg Mn/kg body mass) for 14 weeks, whereas control (CN) rats were fed the control diet and received sterile saline injections. At the conclusion of the study, both blood and brain Mn and Fe levels were determined by atomic absorption spectroscopy and magnetic resonance imaging. The data indicate that changes in dietary Fe levels (either increased or decreased) result in regionally specific increases in brain Mn levels compared with CN or MnT animals. Furthermore, there was no difference in either Fe or Mn accumulation between FeS or FeD animals. These data suggest that dietary Fe manipulation, whether increased or decreased, may contribute to brain Mn deposition in populations vulnerable to increased Mn exposure.

  11. High-temperature performance prediction of iron ore fines and the ore-blending programming problem in sintering

    Institute of Scientific and Technical Information of China (English)

    Bing-ji Yan; Jian-liang Zhang; Hong-wei Guo; Ling-kun Chen; Wei Li

    2014-01-01

    The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effec-tive than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.

  12. Interaction genotype by season and its influence on the identification of beans with high content of zinc and iron

    Directory of Open Access Journals (Sweden)

    Camila Andrade Silva

    2012-01-01

    Full Text Available The mineral contents in common bean seeds are influenced, in addition to genetic variation, by environmental crop conditions, especially by the soil type and chemical composition and by the genotype x environment interaction. This study was carried out to verify if the zinc and iron contents are affected by the crop growing period. Ten lines with high iron and zinc contents and ten with low contents were assessed in three seasons: "wet season" of 2009/2010 (sowing in November; "dry season" of 2010 (sowing in February and "winter season" of 2010 (sowing in July, in Lavras, Minas Gerais State, Brazil. The experimental design used was randomized blocks with three replications and plots consisting of two rows of two meters, with a spacing of 0.50 m. The seeds harvested were assessed in regard to iron and zinc mineral contents. The greatest contents were observed in the winter season and the smallest ones in the dry season, with sowing in February. It was observed that in the mean of the three harvests, the lines classified as having high iron and zinc content exhibited an iron quantity 11.0% and a zinc quantity 6.8% above those of low content. The lines by seasons interaction occurs. However, its interference in identification of the groups with high and low content of the two nutrients is not great.

  13. Nitrogen-doped graphene-wrapped iron nanofragments for high-performance oxygen reduction electrocatalysts

    Science.gov (United States)

    Lee, Jang Yeol; Kim, Na Young; Shin, Dong Yun; Park, Hee-Young; Lee, Sang-Soo; Joon Kwon, S.; Lim, Dong-Hee; Bong, Ki Wan; Son, Jeong Gon; Kim, Jin Young

    2017-03-01

    Transition metals, such as iron (Fe)- or cobalt (Co)-based nanomaterials, are promising electrocatalysts for oxygen reduction reactions (ORR) in fuel cells due to their high theoretical activity and low cost. However, a major challenge to using these metals in place of precious metal catalysts for ORR is their low efficiency and poor stability, thus new concepts and strategies should be needed to address this issue. Here, we report a hybrid aciniform nanostructures of Fe nanofragments embedded in thin nitrogen (N)-doped graphene (Fe@N-G) layers via a heat treatment of graphene oxide-wrapped iron oxide (Fe2O3) microparticles with melamine. The heat treatment leads to transformation of Fe2O3 microparticles to nanosized zero-valent Fe fragments and formation of core-shell structures of Fe nanofragments and N-doped graphene layers. Thin N-doped graphene layers massively promote electron transfer from the encapsulated metals to the graphene surface, which efficiently optimizes the electronic structure of the graphene surface and thereby triggers ORR activity at the graphene surface. With the synergistic effect arising from the N-doped graphene and Fe nanoparticles with porous aciniform nanostructures, the Fe@N-G hybrid catalyst exhibits high catalytic activity, which was evidenced by high E1/2 of 0.82 V, onset potential of 0.93 V, and limiting current density of 4.8 mA cm-2 indicating 4-electron ORR, and even exceeds the catalytic stability of the commercial Pt catalyst.

  14. Unraveling the complexity of iron oxides at high pressure and temperature: Synthesis of Fe5O6.

    Science.gov (United States)

    Lavina, Barbara; Meng, Yue

    2015-06-01

    The iron-oxygen system is the most important reference of rocks' redox state. Even as minor components, iron oxides can play a critical role in redox equilibria, which affect the speciation of the fluid phases chemical differentiation, melting, and physical properties. Until our recent finding of Fe4O5, iron oxides were assumed to comprise only the polymorphs of FeO, Fe3O4, and Fe2O3. Combining synthesis at high pressure and temperature with microdiffraction mapping, we have identified yet another distinct iron oxide, Fe5O6. The new compound, which has an orthorhombic structure, was obtained in the pressure range from 10 to 20 GPa upon laser heating mixtures of iron and hematite at ~2000 K, and is recoverable to ambient conditions. The high-pressure orthorhombic iron oxides Fe5O6, Fe4O5, and h-Fe3O4 display similar iron coordination geometries and structural arrangements, and indeed exhibit coherent systematic behavior of crystallographic parameters and compressibility. Fe5O6, along with FeO and Fe4O5, is a candidate key minor phase of planetary interiors; as such, it is of major petrological and geochemical importance. We are revealing an unforeseen complexity in the Fe-O system with four different compounds-FeO, Fe5O6, Fe4O5, and h-Fe3O4-in a narrow compositional range (0.75 < Fe/O < 1.0). New, finely spaced oxygen buffers at conditions of the Earth's mantle can be defined.

  15. Flexural Strength and Toughness of Austenitic Stainless Steel Reinforced High-Cr White Cast Iron Composite

    Science.gov (United States)

    Sallam, H. E. M.; Abd El-Aziz, Kh.; Abd El-Raouf, H.; Elbanna, E. M.

    2013-12-01

    Flexural behavior of high-Cr white cast iron (WCI) reinforced with different shapes, i.e., I- and T-sections, and volume fractions of austenitic stainless steel (310 SS) were examined under three-point bending test. The dimensions of casted beams used for bending test were (50 × 100 × 500 mm3). Carbon and alloying elements diffusion enhanced the metallurgical bond across the interface of casted beams. Carbon diffusion from high-Cr WCI into 310 SS resulted in the formation of Cr-carbides in 310 SS near the interface and Ni diffusion from 310 SS into high-Cr WCI led to the formation of austenite within a network of M7C3 eutectic carbides in high-Cr WCI near the interface. Inserting 310 SS plates into high-Cr WCI beams resulted in a significant improvement in their toughness. All specimens of this metal matrix composite failed in a ductile mode with higher plastic deformation prior to failure. The high-Cr WCI specimen reinforced with I-section of 310 SS revealed higher toughness compared to that with T-section at the same volume fraction. The presence of the upper flange increased the reinforcement efficiency for delaying the crack growth.

  16. SPHERICAL MICROSTRUCTURE FORMATION OF THE SEMI-SOLID HIGH CHROMIUM CAST IRON Cr20Mo2

    Institute of Scientific and Technical Information of China (English)

    W.M. Mao; A.M. Zhao; X.Y. Zhong

    2004-01-01

    The nondendritic semi-solid slurry preparation of high chromium cast iron Cr20Mo2 has been studied in this paper. The experiments show that the proeutectic austenitic particles are more spherical under a larger stirring power condition, even if the stirring time is shorter, while the proeutectic austenitic particles are not very much spherical under a smaller stirring power condition and some proeutectic austenitic dendrites also exist, even if the stirring time is very long. The experiments also show that when stirred for 5 6 minutes under the test condition, the semi-solid slurry with 40vol. %-50vol. % solid fraction and spherical proeutectic austenite in the size of 50-80μm can be obtained.

  17. Design and control of chemical compositions for high-performance austempered ductile iron

    Directory of Open Access Journals (Sweden)

    Gong Wenbang

    2012-05-01

    Full Text Available This paper presents the effects of chemical compositions of austempered ductile iron (ADI on casting quality, heat treatment process parameters and mechanical properties of final products. Through experiment and production practice, the impacts of carbon equivalent on ADI and its mechanical properties have been studied. Proper content ranges for carbon and silicon have been obtained to avoid ADI casting shrinkage and graphite floatation, as well as to achieve the optimal mechanical properties. According to the impact of silicon content on austenite phase transformation, the existing form of carbon in ADI has been analyzed, and also the formula and diagram showing the relationship between austenitizing temperature and carbon content in austenite have been deduced. The chemical composition range for high performance ADI and its control points have been recommended, to serve as a reference for production process.

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

    Science.gov (United States)

    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.

  19. High pressure superconductivity in iron-based layered compounds studied using designer diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Tsoi, Georgiy; Stemshorn, Andrew K; Vohra, Yogesh K [Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294 (United States); Wu, Phillip M [Department of Physics, Duke University, Durham, NC 27708 (United States); Hsu, F C; Huang, Y L; Wu, M K; Yeh, K W [Institute of Physics, Academia Sinica-Nankang, Taipei, Taiwan (China); Weir, Samuel T [Lawrence Livermore National Laboratory, Mail Stop L-041, Livermore, CA 94550 (United States)

    2009-06-10

    High pressure superconductivity in iron-based superconductor FeSe{sub 0.5}Te{sub 0.5} has been studied up to 15 GPa and 10 K using an eight probe designer diamond anvil in a diamond anvil cell device. Four probe electrical resistance measurements show the onset of superconductivity (T{sub c}) at 14 K at ambient pressure with T{sub c} increasing with increasing pressure to 19 K at a pressure of 3.6 GPa. At higher pressures beyond 3.6 GPa, T{sub c} decreases and extrapolation suggests non-superconducting behavior above 10 GPa. The loss of superconductivity coincides with the pressure induced disordering of the Fe(SeTe){sub 4} tetrahedra reported at 11 GPa in x-ray diffraction studies at ambient temperature. (fast track communication)

  20. Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Day, S D; Haslam, J J; Farmer, J C; Rebak, R B

    2007-08-10

    Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepared ribbons. Results show that the amorphous alloys can be exposed to 600 C for 1-hr. without losing the corrosion resistance; however, when the ribbons were exposed at 800 C for 1-hr. their localized corrosion resistance decreased significantly.

  1. Microstructure and wear resistance of high chromium cast iron containing niobium

    Directory of Open Access Journals (Sweden)

    Zhang Zhiguo

    2014-05-01

    Full Text Available In the paper, the effect of niobium addition on the microstructure, mechanical properties and wear resistance of high chromium cast iron has been studied. The results show that the microstructure of the heat-treated alloys is composed of M7C3 and M23C6 types primary carbide, eutectic carbide, secondary carbide and a matrix of martensite and retained austenite. NbC particles appear both inside and on the edge of the primary carbides. The hardness of the studied alloys maintains around 66 HRC, not significantly affected by the Nb content within the selected range of 0.48%-0.74%. The impact toughness of the alloys increases with increasing niobium content. The wear resistance of the specimens presents little variation in spite of the increase of Nb content under a light load of 40 N. However, when heavier loads of 70 and 100 N are applied, the wear resistance increases with increasing Nb content.

  2. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  3. Development of a High Strength Isothermally Heat-Treated Nodular Iron Road Wheel Arm

    Science.gov (United States)

    1985-03-31

    Ductile Iron . ADI = Austempered Ductile I ron. 19. ABSTRACT (Continue on...Characterization. 23 HAYES-ALBION CORP AUSTEMPERED DUCTILE IRON 200 KSI loo0 U’T.S 20o 1 YIELD KS oo" 10_ 10 - S% * . " ’"ELONGATION E-. I 50 HARDNESS 300 FT.LBS...manufacture, and testing of a proposed road wheel arm for the Ml tank. The material selected is bainitic ductile iron (BDI). This material made by the

  4. Safety implications of high-field MRI: actuation of endogenous magnetic iron oxides in the human body.

    Directory of Open Access Journals (Sweden)

    Jon Dobson

    Full Text Available BACKGROUND: Magnetic Resonance Imaging scanners have become ubiquitous in hospitals and high-field systems (greater than 3 Tesla are becoming increasingly common. In light of recent European Union moves to limit high-field exposure for those working with MRI scanners, we have evaluated the potential for detrimental cellular effects via nanomagnetic actuation of endogenous iron oxides in the body. METHODOLOGY: Theoretical models and experimental data on the composition and magnetic properties of endogenous iron oxides in human tissue were used to analyze the forces on iron oxide particles. PRINCIPAL FINDING AND CONCLUSIONS: Results show that, even at 9.4 Tesla, forces on these particles are unlikely to disrupt normal cellular function via nanomagnetic actuation.

  5. High-Cycle Fatigue Resistance of Si-Mo Ductile Cast Iron as Affected by Temperature and Strain Rate

    Science.gov (United States)

    Matteis, Paolo; Scavino, Giorgio; Castello, Alessandro; Firrao, Donato

    2015-09-01

    Silicon-molybdenum ductile cast irons are used to fabricate exhaust manifolds of internal combustion engines of large series cars, where the maximum pointwise temperature at full engine load may be higher than 973 K (700 °C). In this application, high-temperature oxidation and thermo-mechanical fatigue (the latter being caused by the engine start and stop and by the variation of its power output) have been the subject of several studies and are well known, whereas little attention has been devoted to the high-cycle fatigue, arising from the engine vibration. Therefore, the mechanical behavior of Si-Mo cast iron is studied here by means of stress-life fatigue tests up to 10 million cycles, at temperatures gradually increasing up to 973 K (700 °C). The mechanical characterization is completed by tensile and compressive tests and ensuing fractographic examinations; the mechanical test results are correlated with the cast iron microstructure and heat treatment.

  6. Iron-nucleated folding of a metalloprotein in high urea: resolution of metal binding and protein folding events.

    Science.gov (United States)

    Morleo, Anna; Bonomi, Francesco; Iametti, Stefania; Huang, Victor W; Kurtz, Donald M

    2010-08-10

    Addition of iron salts to chaotrope-denatured aporubredoxin (apoRd) leads to nearly quantitative recovery of its single Fe(SCys)(4) site and native protein structure without significant dilution of the chaotrope. This "high-chaotrope" approach was used to examine iron binding and protein folding events using stopped-flow UV-vis absorption and CD spectroscopies. With a 100-fold molar excess of ferrous iron over denatured apoRd maintained in 5 M urea, the folded holoFe(III)Rd structure was recovered in >90% yield with a t(1/2) of Ser iron ligand variants support formation of an unfolded-Fe(SCys)(3) complex between steps 1 and 2, which we propose is the key nucleation event that pulls together distal regions of the protein chain. These results show that folding of chaotrope-denatured apoRd is iron-nucleated and driven by extraordinarily rapid formation of the Fe(SCys)(4) site from an essentially random coil apoprotein. This high-chaotrope, multispectroscopy approach could clarify folding pathways of other [M(SCys)(3)]- or [M(SCys)(4)]-containing proteins.

  7. Manufacture of iron-based, amorphous coatings with high fracture toughness

    Science.gov (United States)

    Bobzin, K.; Öte, M.; Königstein, T.

    2017-03-01

    Amorphous iron-based material have excellent corrosion behaviour, show good tribological performances and exhibit interesting thermophysical properties. The deposition as a coating system by thermal spraying technology is an innovative approach to manufacture these materials. In this study, the mechanical properties of three iron-based amorphous coatings with different chromium content xCr = 0, 5 and 15 at.% are presented deposited by means of High Velocity Oxygen Fuel Spraying. For the determination of the amorphous content the linear relationship between crystallization energy and amount of amorphous structures is used. Comparing the crystallization energies of amorphous ribbons manufactured by melt spinning to those of feedstock materials and free standing coatings, assumptions regarding the amorphous contents are drawn. The results show that the amorphous content in the feedstock material is influenced by the amount of chromium content. Furthermore, the amorphous content of all coatings do not exceed those of the feedstock materials. Powder xCr = 15 at.% and the corresponding coating exhibit smallest amount of amorphous structure, presumably due to a not fully melted state of the impacting particles. The values of fracture toughness of the coatings are determined by means of indentation and subsequent measurement of the crack lengths. Furthermore, values of indentation modulus and hardness are measured and compared to each other. While length of indentation cracks decreases with increasing chromium content, an increase in indention modulus and hardness is observed. In comparison to ceramic reference YSZ and the steel reference 1.4404, all amorphous coatings show promising properties such as low indentation crack lengths and high hardness.

  8. Conformable actively multiplexed high-density surface electrode array for brain interfacing

    Science.gov (United States)

    Rogers, John; Kim, Dae-Hyeong; Litt, Brian; Viventi, Jonathan

    2015-01-13

    Provided are methods and devices for interfacing with brain tissue, specifically for monitoring and/or actuation of spatio-temporal electrical waveforms. The device is conformable having a high electrode density and high spatial and temporal resolution. A conformable substrate supports a conformable electronic circuit and a barrier layer. Electrodes are positioned to provide electrical contact with a brain tissue. A controller monitors or actuates the electrodes, thereby interfacing with the brain tissue. In an aspect, methods are provided to monitor or actuate spatio-temporal electrical waveform over large brain surface areas by any of the devices disclosed herein.

  9. High-protein diet induces oxidative stress in rat brain: protective action of high-intensity exercise against lipid peroxidation

    OpenAIRE

    Camiletti-Moir??n, Daniel; Aparicio Garc??a-Molina, Virginia A.; Nebot Valenzuela, Elena; Medina, Gerardo; Mart??nez, Rosario; Kapravelou, Garyfallia; Andrade, Ana; Porres-Foulquie, Jes??s; L??pez-Jurado, Mar??a; Aranda Ram??rez, Pilar

    2015-01-01

    diets as well as aerobic exercise could promote antioxidant capacity and consequently reduce free radicals overproduction on brain. However, little is know regarding to the high-protein diets and high intensity exercise on oxidative stress production. The aim of this study was to analyse the effects of high-protein diets and high-intensity exercise (HIE) on brain oxidative stress markers. Materials and Methods: A total of 40 male Wistar rats were randomly distributed i...

  10. Fetal and neonatal iron deficiency exacerbates mild thyroid hormone insufficiency effects on male thyroid hormone levels and brain thyroid hormone-responsive gene expression.

    Science.gov (United States)

    Bastian, Thomas W; Prohaska, Joseph R; Georgieff, Michael K; Anderson, Grant W

    2014-03-01

    Fetal/neonatal iron (Fe) and iodine/TH deficiencies lead to similar brain developmental abnormalities and often coexist in developing countries. We recently demonstrated that fetal/neonatal Fe deficiency results in a mild neonatal thyroidal impairment, suggesting that TH insufficiency contributes to the neurodevelopmental abnormalities associated with Fe deficiency. We hypothesized that combining Fe deficiency with an additional mild thyroidal perturbation (6-propyl-2-thiouracil [PTU]) during development would more severely impair neonatal thyroidal status and brain TH-responsive gene expression than either deficiency alone. Early gestation pregnant rats were assigned to 7 different treatment groups: control, Fe deficient (FeD), mild TH deficient (1 ppm PTU), moderate TH deficient (3 ppm PTU), severe TH deficient (10 ppm PTU), FeD/1 ppm PTU, or FeD/3 ppm PTU. FeD or 1 ppm PTU treatment alone reduced postnatal day 15 serum total T4 concentrations by 64% and 74%, respectively, without significantly altering serum total T3 concentrations. Neither treatment alone significantly altered postnatal day 16 cortical or hippocampal T3 concentrations. FeD combined with 1 ppm PTU treatment produced a more severe effect, reducing serum total T4 by 95%, and lowering hippocampal and cortical T3 concentrations by 24% and 31%, respectively. Combined FeD/PTU had a more severe effect on brain TH-responsive gene expression than either treatment alone, significantly altering Pvalb, Dio2, Mbp, and Hairless hippocampal and/or cortical mRNA levels. FeD/PTU treatment more severely impacted cortical and hippocampal parvalbumin protein expression compared with either individual treatment. These data suggest that combining 2 mild thyroidal insults during development significantly disrupts thyroid function and impairs TH-regulated brain gene expression.

  11. Sex, the brain and hypertension: brain oestrogen receptors and high blood pressure risk factors.

    Science.gov (United States)

    Hay, Meredith

    2016-01-01

    Hypertension is a major contributor to worldwide morbidity and mortality rates related to cardiovascular disease. There are important sex differences in the onset and rate of hypertension in humans. Compared with age-matched men, premenopausal women are less likely to develop hypertension. However, after age 60, the incidence of hypertension increases in women and even surpasses that seen in older men. It is thought that changes in levels of circulating ovarian hormones as women age may be involved in the increase in hypertension in older women. One of the key mechanisms involved in the development of hypertension in both men and women is an increase in sympathetic nerve activity (SNA). Brain regions important for the regulation of SNA, such as the subfornical organ, the paraventricular nucleus and the rostral ventral lateral medulla, also express specific subtypes of oestrogen receptors. Each of these brain regions has also been implicated in mechanisms underlying risk factors for hypertension such as obesity, stress and inflammation. The present review brings together evidence that links actions of oestrogen at these receptors to modulate some of the common brain mechanisms involved in the ability of hypertensive risk factors to increase SNA and blood pressure. Understanding the mechanisms by which oestrogen acts at key sites in the brain for the regulation of SNA is important for the development of novel, sex-specific therapies for treating hypertension. © 2016 Authors; published by Portland Press Limited.

  12. Tissue distribution of manganese in iron-sufficient or iron-deficient rats after stainless steel welding-fume exposure.

    Science.gov (United States)

    Park, Jung-Duck; Kim, Ki-Young; Kim, Dong-Won; Choi, Seong-Jin; Choi, Byung-Sun; Chung, Yong Hyun; Han, Jeong Hee; Sung, Jae Hyuck; Kwon, Il Hoon; Mun, Je-Hyeok; Yu, Il Je

    2007-05-01

    Welders can be exposed to high levels of manganese through welding fumes. Although it has already been suggested that excessive manganese exposure causes neurotoxicity, called manganism, the pathway of manganese transport to the brain with welding-fume exposure remains unclear. Iron is an essential metal that maintains a homeostasis in the body. The divalent metal transporter 1 (DMT1) transports iron and other divalent metals, such as manganese, and the depletion of iron is known to upregulate DMT1 expression. Accordingly, this study investigated the tissue distribution of manganese in iron-sufficient and iron-deficient rats after welding-fume exposure. The feeding of an iron-deficient diet for 4 wk produced a depletion of body iron, such as decreased iron levels in the serum and tissues, and upregulated the DMT1 expression in the rat duodenum. The iron-sufficient and iron-deficient rats were then exposed to welding fumes generated from manual metal arc stainless steel at a concentration of 63.5 +/- 2.3 mg/m3 for 2 h per day over a 30-day period. Animals were sacrificed on days 1, 15, and 30. The level of body iron in the iron-deficient rats was restored to the control level after the welding-fume exposure. However, the tissue distributions of manganese after the welding-fume exposure showed similar patterns in both the iron-sufficient and iron-deficient groups. The concentration of manganese increased in the lungs and liver on days 15 and 30, and increased in the olfactory bulb on day 30. Slight and heterogeneous increases of manganese were observed in different brain regions. Consequently, these findings suggest that the presence of Fe in the inhaled welding fumes may not have a significant effect on the uptake of Mn into the brain. Thus, the condition of iron deficiency did not seem to have any apparent effect on the transport of Mn into the brain after the inhalation of welding fumes.

  13. The effects of temperature and light elements on the interfacial tension of liquid iron under high pressure

    Science.gov (United States)

    Terasaki, H.; Urakawa, S.; Funakoshi, K.; Ohtani, E.; Suzuki, A.; Nishida, K.; Sakamaki, T.; Nishiyama, N.; Wang, Y.

    2007-12-01

    Interfacial tension is one of the most important properties of liquid iron-alloy to control the core formation process in the Earth and planets. The aim of this study is to clarify the effects of temperature and light elements (S and P) on the interfation tension of liquid iron under high pressure. In this study, high pressure in-situ measurement of interfacial tension was carried out for the liquid Fe-S and Fe-P alloys using sessile drop method combined with X-ray radiography technique up to 2 GPa and 1923 K. The sessile drop method has been widely used for measurement of surface and interfacial tensions at ambient pressure. The effect of temperature on the interfacial tension for both Fe-S and Fe-P liquids is quite small in the range of measurement (1623 - 1923 K). The interfacial tension of liquid Fe-S decreases linearly from 802 to 112 mN/m with increasing sulphur content of 0 - 40 at%. Thus, sulphur reduces significantly the interfacial tension of liquid iron. On the other hand, phosphorus does not affect to the interfacial tension of liquid iron. These tendencies are in good agreement with the data measured at ambient pressure. Therefore, the behaviour of light elements on the interface at ambient pressure is maintained at least up to 2 GPa and the effect of light elements on the interfacial tension of liquid iron depends on the element species. The shape change of the liquid Fe-S was observed before and after quenching. This suggests that the in-situ measurement at high pressure and temperature is essential in order to obtain the true interfacial tension, i.e. interconnectivity of liquid iron-alloy.

  14. Prediction of superconducting iron-bismuth intermetallic compounds at high pressure

    CERN Document Server

    Amsler, Maximilian; Wolverton, Chris

    2016-01-01

    The synthesis of materials in high-pressure experiments has recently attracted increasing attention, especially since the discovery of record breaking superconducting temperatures in the sulfur-hydrogen and other hydrogen-rich systems. Commonly, the initial precursor in a high pressure experiment contains constituent elements that are known to form compounds at ambient conditions, however the discovery of high-pressure phases in systems immiscible under ambient conditions poses an additional materials design challenge. We performed an extensive multi component $ab\\,initio$ structural search in the immiscible Fe--Bi system at high pressure and report on the surprising discovery of two stable compounds at pressures above $\\approx36$ GPa, FeBi$_2$ and FeBi$_3$. According to our predictions, FeBi$_2$ is a metal at the border of magnetism with a conventional electron-phonon mediated superconducting transition temperature of $T_{\\rm c}=1.3$ K at 40 GPa. In analogy to other iron-based materials, FeBi$_2$ is possibly...

  15. New rat models of iron sucrose-induced iron overload.

    Science.gov (United States)

    Vu'o'ng Lê, Bá; Khorsi-Cauet, Hafida; Villegier, Anne-Sophie; Bach, Véronique; Gay-Quéheillard, Jérôme

    2011-07-01

    The majority of murine models of iron sucrose-induced iron overload were carried out in adult subjects. This cannot reflect the high risk of iron overload in children who have an increased need for iron. In this study, we developed four experimental iron overload models in young rats using iron sucrose and evaluated different markers of iron overload, tissue oxidative stress and inflammation as its consequences. Iron overload was observed in all iron-treated rats, as evidenced by significant increases in serum iron indices, expression of liver hepcidin gene and total tissue iron content compared with control rats. We also showed that total tissue iron content was mainly associated with the dose of iron whereas serum iron indices depended essentially on the duration of iron administration. However, no differences in tissue inflammatory and antioxidant parameters from controls were observed. Furthermore, only rats exposed to daily iron injection at a dose of 75 mg/kg body weight for one week revealed a significant increase in lipid peroxidation in iron-treated rats compared with their controls. The present results suggest a correlation between iron overload levels and the dose of iron, as well as the duration and frequency of iron injection and confirm that iron sucrose may not play a crucial role in inflammation and oxidative stress. This study provides important information about iron sucrose-induced iron overload in rats and may be useful for iron sucrose therapy for iron deficiency anemia as well as for the prevention and diagnosis of iron sucrose-induced iron overload in pediatric patients.

  16. Discovery of the recoverable high-pressure iron oxide Fe[subscript 4]O[subscript 5

    Energy Technology Data Exchange (ETDEWEB)

    Lavina, Barbara; Dera, Przemyslaw; Kim, Eunja; Meng, Yue; Downs, Robert T.; Weck, Philippe F.; Sutton, Stephen R.; Zhao, Yusheng (UC); (CIW); (UNLV); (Ariz)

    2016-08-15

    Phases of the iron-oxygen binary system are significant to most scientific disciplines, directly affecting planetary evolution, life, and technology. Iron oxides have unique electronic properties and strongly interact with the environment, particularly through redox reactions. The iron-oxygen phase diagram therefore has been among the most thoroughly investigated, yet it still holds striking findings. Here, we report the discovery of an iron oxide with formula Fe{sub 4}O{sub 5}, synthesized at high pressure and temperature. The previously undescribed phase, stable from 5 to at least 30 GPa, is recoverable to ambient conditions. First-principles calculations confirm that the iron oxide here described is energetically more stable than FeO + Fe{sub 3}O{sub 4} at pressure greater than 10 GPa. The calculated lattice constants, equation of states, and atomic coordinates are in excellent agreement with experimental data, confirming the synthesis of Fe{sub 4}O{sub 5}. Given the conditions of stability and its composition, Fe{sub 4}O{sub 5} is a plausible accessory mineral of the Earth's upper mantle. The phase has strong ferrimagnetic character comparable to magnetite. The ability to synthesize the material at accessible conditions and recover it at ambient conditions, along with its physical properties, suggests a potential interest in Fe{sub 4}O{sub 5} for technological applications.

  17. Human serum transferrin: is there a link among autism, high oxalate levels, and iron deficiency anemia?

    Science.gov (United States)

    Luck, Ashley N; Bobst, Cedric E; Kaltashov, Igor A; Mason, Anne B

    2013-11-19

    It has been previously suggested that large amounts of oxalate in plasma could play a role in autism by binding to the bilobal iron transport protein transferrin (hTF), thereby interfering with iron metabolism by inhibiting the delivery of iron to cells. By examining the effect of the substitution of oxalate for the physiologically utilized synergistic carbonate anion in each lobe of hTF, we sought to provide a molecular basis for or against such a role. Our work clearly shows both qualitatively (6 M urea gels) and quantitatively (kinetic analysis by stopped-flow spectrofluorimetry) that the presence of oxalate in place of carbonate in each binding site of hTF does indeed greatly interfere with the removal of iron from each lobe (in the absence and presence of the specific hTF receptor). However, we also clearly demonstrate that once the iron is bound within each lobe of hTF, neither anion can displace the other. Additionally, as verified by urea gels and electrospray mass spectrometry, formation of completely homogeneous hTF-anion complexes requires that all iron must first be removed and hTF then reloaded with iron in the presence of either carbonate or oxalate. Significantly, experiments described here show that carbonate is the preferred binding partner; i.e., even if an equal amount of each anion is available during the iron loading process, the hTF-carbonate complex is formed.

  18. "IRON DEFICIENCY ANEMIA AND ENERGY AND NUIRIENT INTAKES IN 14-18 YEAR OLD HIGH SCHOOL GIRLS IN TEHRAN"

    OpenAIRE

    A.Djazayery; Djalali, M; Z.Abdollahi

    1991-01-01

    The purpose of this study was evaluation of iron status as well as protein and iron intakes in 14-18 year old girls in high schools in the south of Tehran. A total of 268 girls were chosen at random for a dietary survey using the 24-hr dietary recall method and the biochemical tests were made on 109 of the girls. The results indicate that: compared with the WHO standards, hemoglobin in 0.9%, hematocrit in 2.8% and MCHC in 13.8% of the girls were lower than the respective standards, and TJBC i...

  19. Evaluation of the Combined Effects of Gamma Radiation and High Dietary Iron on Peripheral Leukocyte Distribution and Function

    Science.gov (United States)

    Crucian, Brian E.; Morgan, Jennifer L. L.; Quiriarte, Heather A.; Sams, Clarence F.; Smith, Scott M.; Zwart, Sara R.

    2011-01-01

    NASA is concerned with the health risks to astronauts, particularly those risks related to radiation exposure. Both radiation and increased iron stores can independently increase oxidative damage, resulting in protein, lipid and DNA oxidation. Oxidative stress increases the risk of many health problems including cancer, cataracts, and heart disease. This study, a subset of a larger interdisciplinary investigation of the combined effect of iron overload on sensitivity to radiation injury, monitored immune parameters in the peripheral blood of rats subjected to gamma radiation, high dietary iron or both. Specific immune measures consisted of (A) peripheral leukocyte distribution; (B) plasma cytokine levels; (C) cytokine production profiles following whole blood stimulation of either T cells or monocytes.

  20. Identification of Iron Oxides Qualitatively/Quantitatively Formed during the High Temperature Oxidation of Superalloys in Air and Steam Environments

    Institute of Scientific and Technical Information of China (English)

    M.Siddique; N.Hussain; M.Shafi

    2009-01-01

    Mossbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L (1.4306S), Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690, at 1200℃ exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, whereas Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of lnconel-690 no iron oxide, with established Mossbauer parameters, was detected.

  1. Effect of Rare Earth Alloy Modification on High Carbon Equivalent Gray Cast Iron of Automotive Brake Drum

    Institute of Scientific and Technical Information of China (English)

    ZHANG Daowen; LI Zhu; HUANG Jie

    2012-01-01

    Effect of rare earth alloy modification on properties and microstructure of high carbon equivalent gray cast iron was investigated.The experimental results show that in the way of mechanical property,when the addition of rare earth alloy is 0.2% and 0.3%,the tensile strength of cast iron increases.In the way of microstructure,the addition of rare earth alloy increases the number of primary austenite dendrites,reduces secondary dendritic arm spacing,and changes the eutectic size and quantity.When rare earth alloy is added into gray cast iron,the morphology and quantity of graphite play a major role on the improvement of tensile strength.

  2. Atomistic simulation of the premelting of iron and aluminum : Implications for high-pressure melting-curve measurements

    NARCIS (Netherlands)

    Starikov, Sergey V.; Stegailov, Vladimir V.

    2009-01-01

    Using atomistic simulations we show the importance of the surface premelting phenomenon for the melting-curve measurements at high pressures. The model under consideration mimics the experimental conditions deployed for melting studies with diamond-anvil cells. The iron is considered in this work be

  3. Study on fragmentation and dissolution behavior of carbide in a hot-rolled hypereutectic high chromium cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei; Jiang, Yehua, E-mail: jiangyehua@kmust.edu.cn; Xiao, Han; Tan, Jun

    2015-01-05

    Highlights: • The method to prepare Carbon steel/High chromium iron is totally new. • High chromium iron can achieve small plastic deformation during hot rolling process. • Carbides in high chromium irons are crushed, refined obviously and becoming isolated, which is benefit to improve the impact toughness. • The carbide fragmentation and dissolution behavior of the hot-rolled HCCI were analyzed. - Abstract: A sandwich-structured composite containing a hypereutectic high chromium cast iron (HCCI) and low carbon steel (LCS) claddings was newly fabricated by centrifugal casting, then the blank was hot-rolled into composite plate. The carbide fragmentation and dissolution behavior of the hot-rolled HCCI were analyzed. During hot rolling, significant refinement of carbides was discovered in hot-rolled HCCI specimens. The carbides were broken and partly dissolved into the austenite matrix. The results show that carbides are firstly dissolved under the action of stress. There are grooves appeared at the boundaries of the carbides. The grooves reduce the cross section of the carbide. When the cross section of the carbide reaches to the required minimum critical cross section, the carbide breaks through the tensile force. After break, carbides continue to dissolve since more interfaces between the matrix and carbides are generated. The secondary carbides precipitated due to the dissolution are index as fcc and stacking faults parallel to the {1 1 1} are observed.

  4. Size-controlled synthesis of hierarchical nanoporous iron based fluorides and their high performances in rechargeable lithium ion batteries.

    Science.gov (United States)

    Lu, Yan; Wen, Zhao-yin; Jin, Jun; Wu, Xiang-wei; Rui, Kun

    2014-06-21

    High performance nanostructured iron fluorides with controllable sizes were successfully synthesized using oleylamine as a size tuning agent for the first time. They exhibited excellent cathode performances with large retensive capacities exceeding 200 mA h g(-1) after 50 cycles and outstanding rate performances of nearly 100 mA h g(-1) even at 10 C.

  5. 1H NMR of High-Potential Iron-Sulfur Protein from the Purple Non-Sulfur Bacterium Rhodoferax fermentans

    DEFF Research Database (Denmark)

    Ciurli, Stefano; Cremonini, Mauro Andrea; Kofod, Pauli

    1996-01-01

    Oxidized and reduced forms of high-potential iron-sulfur protein (HiPIP) from the purple non-sulfur photosynthetic bacterium Rhodoferux fermentans have been characterized using 1H-NMR spectroscopy. Pairwise and sequence-specific assignments of hyperfine-shifted 1H-NMR signals to protons of cysteine...

  6. Ab Initio Study of the Structure and Stability of High-Pressure Iron-Bearing Dolomite

    Science.gov (United States)

    Solomatova, N. V.; Asimow, P. D.

    2016-12-01

    Carbon is subducted into the mantle primarily in the form of metasomatically calcium-enriched basaltic rock, calcified serpentinites and carbonaceous ooze, all of which often contain dolomite. End-member CaMg(CO3)2 dolomite typically breaks down upon compression into two carbonates at 5-6 GPa in the temperature range of 800-1200 K [1]. However, high-pressure X-ray diffraction experiments have recently shown that the presence of iron may be sufficient to stabilize high-pressure dolomite over single-cation carbonates above 35 GPa [2,3]. The structure and equation of state of high-pressure dolomite phases have been debated, creating a need for theoretical calculations. Using density functional theory interfaced with a genetic algorithm that predicts crystal structures (USPEX), we have found a monoclinic phase with space group C2/c. The C2/c structure has a lower energy than previously reported dolomite structures at relevant pressures. It is possible that this phase is not achieved experimentally due to a large energy barrier and a correspondingly large required volume drop, resulting in the transformation to metastable dolomite II. We calculate the equation of state of trigonal dolomite, dolomite III and monoclinic C2/c dolomite to 80 GPa with 0 and 50 mol% CaFe(CO3)2 and compare their enthalpies to single-carbonate assemblages. Although end-member C2/c CaMg(CO3)2 dolomite is not stable relative to single-cation carbonates, C2/c CaMg0.5Fe0.5(CO3)2 is preferred over single-cation carbonates at high pressures. Thus, iron-bearing C2/c dolomite may be an important host phase for carbon in slabs subducted into the lower mantle. [1] Shirasaka, M., et al. (2002) American Mineralogist, 87, 922-930. [2] Mao, Z. et al. (2011) Geophysical Research Letters, 38. [3] Merlini, M. et al. (2012) Proceedings of the National Academy of Sciences, 109, 13509-13514.

  7. Iron oxide nanorods as high-performance magnetic resonance imaging contrast agents

    Science.gov (United States)

    Mohapatra, Jeotikanta; Mitra, Arijit; Tyagi, Himanshu; Bahadur, D.; Aslam, M.

    2015-05-01

    An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods.An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00055f

  8. Effects of carboxylic acids on the uptake of non-transferrin-bound iron by astrocytes.

    Science.gov (United States)

    Keenan, Belinda M; Robinson, Stephen R; Bishop, Glenda M

    2010-01-01

    The concentrations of non-transferrin-bound iron are elevated in the brain during pathological conditions such as stroke and Alzheimer's disease. Astrocytes are specialised for sequestering this iron, however little is known about the mechanisms involved. Carboxylates, such as citrate, have been reported to facilitate iron uptake by intestinal cells. Citrate binds iron and limits its redox activity. The presence of high citrate concentrations in the interstitial fluid of the brain suggests that citrate may be an important ligand for iron transport by astrocytes. This study investigates whether iron accumulation by cultured rat astrocytes is facilitated by citrate or other carboxylates. Contrary to expectations, citrate, tartrate and malate were found to block iron accumulation in a concentration-dependent manner; alpha-ketoglutarate had limited effects, while fumarate, succinate and glutarate had no effect. This blockade was not due to an inhibition of ferric reductase activity. Instead, it appeared to be related to the capacity of these carboxylates to bind iron, since phosphate, which also binds iron, diminished the capacity of citrate, tartrate and malate to block the cellular accumulation of iron. These findings raise the possibility that citrate may have therapeutic potential in the management of neurodegenerative conditions that involve cellular iron overload.

  9. Numerical Analysis of Blast Furnace Performance Under Charging Iron-Bearing Burdens With High Reducibility

    Institute of Scientific and Technical Information of China (English)

    CHU Man-sheng; GUO Xian-zhen; SHEN Feng-man; YAGI Jun-ichiro; NOGAMI Hiroshi

    2007-01-01

    The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply high-reducibility sinter and carbon composite agglomerates for practical application at a blast furnace.

  10. X-ray Absorption Spectroscopic Studies of High-Spin Nonheme (Alkylperoxo)iron(III) Intermediates

    Energy Technology Data Exchange (ETDEWEB)

    Shan,X.; Rohde, J.; Koehntop, K.; Zhou, Y.; Bukowski, M.; Costas, M.; Fujisawa, K.; Que, Jr., L.

    2007-01-01

    The reactions of iron(II) complexes [Fe(Tpt-Bu,i-Pr)(OH)] (1a, Tpt-Bu,i-Pr = hydrotris(3-tert-butyl-5-isopropyl-1-pyrazolyl)borate), [Fe(6-Me2BPMCN)(OTf)2] (1b, 6-Me2BPMCN = N,N'-bis((2-methylpyridin-6-yl)methyl)-N,N'-dimethyl-trans-1,2-diaminocyclohexane), and [Fe(L8Py2)(OTf)](OTf) (1c, L8Py2 = 1,5-bis(pyridin-2-ylmethyl)-1,5-diazacyclooctane) with tert-BuOOH give rise to high-spin FeIII-OOR complexes. X-ray absorption spectra (XAS) of these high-spin species show characteristic features, distinct from those of low-spin Fe-OOR complexes. These include (1) an intense 1s {yields} 3d preedge feature, with an area around 20 units, (2) an edge energy, ranging from 7122 to 7126 eV, that is affected by the coordination environment, and (3) a 1.86-1.96 Angstroms Fe-OOR bond, compared to the 1.78 Angstroms Fe-OOR bond in low-spin complexes. These unique features likely arise from a flexible first coordination sphere in those complexes. The difference in Fe-OOR bond length may rationalize differences in reactivity between low-spin and high-spin FeIII-OOR species.

  11. Laboratory measurements of K-shell transitions in highly charged iron ions

    Science.gov (United States)

    Steinbrügge, René; Rudolph, Jan K.; Bernitt, Sven; Crespo López-Urrutia, José R.

    2016-09-01

    The x-ray spectra of celestial sources show a plethora of features originating from highly charged ions. These can be used to determine the flow, temperatures, and abundances of elements in the star, which are needed to benchmark-stellar evolution models. However, the underlying atomic transition data of the ions are often only known by theoretical calculations, thus testing them in laboratory measurements is crucial. We present our measurements of energies, natural linewidths, radiative and Auger decay rates for K-shell transitions in He-like to F-like iron ions. In this experiments, an electron beam ion trap was used to create a target of highly charged ions, which were resonantly excited by monochromatic light from the PETRA III synchrotron radiation source. Fluorescence was observed while simultaneously detecting photoionization by the change in the ionic charge state. This method, combined with the high resolution of the monochromator used, yields uncertainties on the ppm-level for the excitation energies and below 10% for the linewidths and transition rates, thus providing a valuable benchmark for atomic theory.

  12. Benefits and harms of iron supplementation in iron-deficient and iron-sufficient children.

    Science.gov (United States)

    Domellöf, Magnus

    2010-01-01

    Due to high iron requirements, young children are at risk for iron deficiency anemia. Iron supplements are therefore often recommended, especially since iron deficiency anemia in children is associated with poor neurodevelopment. However, in contrast to most other nutrients, excess iron cannot be excreted by the human body and it has recently been suggested that excessive iron supplementation of young children may have adverse effects on growth, risk of infections, and even on cognitive development. Recent studies support that iron supplements are beneficial in iron-deficient children but there is a risk of adverse effects in those who are iron replete. In populations with a low prevalence of iron deficiency, general supplementation should therefore be avoided. Iron-fortified foods can still be generally recommended since they seem to be safer than medicinal iron supplements, but the level of iron fortification should be limited. General iron supplementation is recommended in areas with a high prevalence of iron deficiency, with the exception of malarious areas where a cautious supplementation approach needs to be adopted, based either on screening or a combination of iron supplements and infection control measures. More studies are urgently needed to better determine the risks and benefits of iron supplementation and iron-fortified foods given to iron-deficient and iron-sufficient children.

  13. Iron-refractory iron deficiency anemia.

    Science.gov (United States)

    Yılmaz Keskin, Ebru; Yenicesu, İdil

    2015-03-05

    Iron is essential for life because it is indispensable for several biological reactions, such as oxygen transport, DNA synthesis, and cell proliferation. Over the past few years, our understanding of iron metabolism and its regulation has changed dramatically. New disorders of iron metabolism have emerged, and the role of iron as a cofactor in other disorders has begun to be recognized. The study of genetic conditions such as hemochromatosis and iron-refractory iron deficiency anemia (IRIDA) has provided crucial insights into the molecular mechanisms controlling iron homeostasis. In the future, these advances may be exploited to improve treatment of both genetic and acquired iron disorders. IRIDA is caused by mutations in TMPRSS6, the gene encoding matriptase-2, which downregulates hepcidin expression under conditions of iron deficiency. The typical features of this disorder are hypochromic, microcytic anemia with a very low mean corpuscular volume of erythrocytes, low transferrin saturation, no (or inadequate) response to oral iron, and only a partial response to parenteral iron. In contrast to classic iron deficiency anemia, serum ferritin levels are usually low-normal, and serum or urinary hepcidin levels are inappropriately high for the degree of anemia. Although the number of cases reported thus far in the literature does not exceed 100, this disorder is considered the most common of the "atypical" microcytic anemias. The aim of this review is to share the current knowledge on IRIDA and increase awareness in this field.

  14. Iron-Refractory Iron Deficiency Anemia

    Science.gov (United States)

    Yılmaz Keskin, Ebru; Yenicesu, İdil

    2015-01-01

    Iron is essential for life because it is indispensable for several biological reactions, such as oxygen transport, DNA synthesis, and cell proliferation. Over the past few years, our understanding of iron metabolism and its regulation has changed dramatically. New disorders of iron metabolism have emerged, and the role of iron as a cofactor in other disorders has begun to be recognized. The study of genetic conditions such as hemochromatosis and iron-refractory iron deficiency anemia (IRIDA) has provided crucial insights into the molecular mechanisms controlling iron homeostasis. In the future, these advances may be exploited to improve treatment of both genetic and acquired iron disorders. IRIDA is caused by mutations in TMPRSS6, the gene encoding matriptase-2, which downregulates hepcidin expression under conditions of iron deficiency. The typical features of this disorder are hypochromic, microcytic anemia with a very low mean corpuscular volume of erythrocytes, low transferrin saturation, no (or inadequate) response to oral iron, and only a partial response to parenteral iron. In contrast to classic iron deficiency anemia, serum ferritin levels are usually low-normal, and serum or urinary hepcidin levels are inappropriately high for the degree of anemia. Although the number of cases reported thus far in the literature does not exceed 100, this disorder is considered the most common of the “atypical” microcytic anemias. The aim of this review is to share the current knowledge on IRIDA and increase awareness in this field. PMID:25805669

  15. CT findings of the brain damages resulting from the high voltage electric injuries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Eun; Kim, Young Keun; Shim, Hyang Yi; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

    1994-02-15

    The purpose of this study is to evaluate the CT features and pathogenesis of the electric brain injuries. We reviewed the CT scans of 3 patients injured by high-voltage electricity. We evaluated the findings early and delayed periods in each patients. The early CT findings were diffuse brain edema, scalp swelling, and focal hemorrhagic contusion. The findings of delayed period were cerebral infarction, pneumocephalus, brain abscess, and pneumatocele. CT was useful to correlate the pathogenesis and variable features of electric brain injuries.

  16. Development of a high angular resolution diffusion imaging human brain template.

    Science.gov (United States)

    Varentsova, Anna; Zhang, Shengwei; Arfanakis, Konstantinos

    2014-05-01

    Brain diffusion templates contain rich information about the microstructure of the brain, and are used as references in spatial normalization or in the development of brain atlases. The accuracy of diffusion templates constructed based on the diffusion tensor (DT) model is limited in regions with complex neuronal micro-architecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DT model and is capable of resolving intravoxel heterogeneity. However, when HARDI is combined with multiple-shot sequences to minimize image artifacts, the scan time becomes inappropriate for human brain imaging. In this work, an artifact-free HARDI template of the human brain was developed from low angular resolution multiple-shot diffusion data. The resulting HARDI template was produced in ICBM-152 space based on Turboprop diffusion data, was shown to resolve complex neuronal micro-architecture in regions with intravoxel heterogeneity, and contained fiber orientation information consistent with known human brain anatomy.

  17. High-field proton magnetic resonance spectroscopy reveals metabolic effects of normal brain aging.

    Science.gov (United States)

    Harris, Janna L; Yeh, Hung-Wen; Swerdlow, Russell H; Choi, In-Young; Lee, Phil; Brooks, William M

    2014-07-01

    Altered brain metabolism is likely to be an important contributor to normal cognitive decline and brain pathology in elderly individuals. To characterize the metabolic changes associated with normal brain aging, we used high-field proton magnetic resonance spectroscopy in vivo to quantify 20 neurochemicals in the hippocampus and sensorimotor cortex of young adult and aged rats. We found significant differences in the neurochemical profile of the aged brain when compared with younger adults, including lower aspartate, ascorbate, glutamate, and macromolecules, and higher glucose, myo-inositol, N-acetylaspartylglutamate, total choline, and glutamine. These neurochemical biomarkers point to specific cellular mechanisms that are altered in brain aging, such as bioenergetics, oxidative stress, inflammation, cell membrane turnover, and endogenous neuroprotection. Proton magnetic resonance spectroscopy may be a valuable translational approach for studying mechanisms of brain aging and pathology, and for investigating treatments to preserve or enhance cognitive function in aging.

  18. In vivo high-resolution diffusion tensor imaging of the mouse brain.

    Science.gov (United States)

    Wu, Dan; Xu, Jiadi; McMahon, Michael T; van Zijl, Peter C M; Mori, Susumu; Northington, Frances J; Zhang, Jiangyang

    2013-12-01

    Diffusion tensor imaging (DTI) of the laboratory mouse brain provides important macroscopic information for anatomical characterization of mouse models in basic research. Currently, in vivo DTI of the mouse brain is often limited by the available resolution. In this study, we demonstrate in vivo high-resolution DTI of the mouse brain using a cryogenic probe and a modified diffusion-weighted gradient and spin echo (GRASE) imaging sequence at 11.7 T. Three-dimensional (3D) DTI of the entire mouse brain at 0.125 mm isotropic resolution could be obtained in approximately 2 h. The high spatial resolution, which was previously only available with ex vivo imaging, enabled non-invasive examination of small structures in the adult and neonatal mouse brains. Based on data acquired from eight adult mice, a group-averaged DTI atlas of the in vivo adult mouse brain with 60 structure segmentations was developed. Comparisons between in vivo and ex vivo mouse brain DTI data showed significant differences in brain morphology and tissue contrasts, which indicate the importance of the in vivo DTI-based mouse brain atlas.

  19. High-Temperature Wide Thermal Hysteresis of an Iron(II Dinuclear Double Helicate

    Directory of Open Access Journals (Sweden)

    Shiori Hora

    2017-07-01

    Full Text Available Two new dinuclear iron(II complexes (1·PF6 and 1·AsF6 of the general formula [FeII2(L2C32](X4·nH2O·mMeCN (X = PF6, n = m = 1.5 for 1·PF6 and X = AsF6, n = 3, m = 1 for 1·AsF6 have been prepared and structurally characterized, where L2C3 is a bis-1,2,3-triazolimine type Schiff-base ligand, 1,1′-[propane-1,3-diylbis(1H-1,2,3-triazole-1,4-diyl]bis{N-[2-(pyridin-2-ylethyl]methanimine}. Single crystal X-ray structure analyses revealed that 1·PF6 and 1·AsF6 are isostructural. The complex-cation [FeII2(L2C32]4+ of both has the same dinuclear double helicate architecture, in which each iron(II center has an N6 octahedral coordination environment. Neighboring helicates are connected by intermolecular π–π interactions to give a chiral one-dimensional (1D structure, and cationic 1D chains with the opposite chirality exist in the crystal lattice to give a heterochiral crystal. Magnetic and differential scanning calorimetry (DSC studies were performed only for 1·AsF6, since the thermal stability in a high-temperature spin crossover (SCO region of 1·PF6 is poorer than that of 1·AsF6. 1·AsF6 shows an unsymmetrical hysteretic SCO between the low-spin–low-spin (LS–LS and high-spin–high-spin (HS–HS states at above room temperature. The critical temperatures of warming (Tc↑ and cooling (Tc↓ modes in the abrupt spin transition area are 485 and 401 K, respectively, indicating the occurrence of 84 K-wide thermal hysteresis in the first thermal cycle.

  20. Phonon Density of States and Sound Velocities of an Iron-Nickel Alloy at High Pressure

    Science.gov (United States)

    Miller, R. A.; Jackson, J. M.; Sturhahn, W.; Murphy, C. A.

    2012-12-01

    Seismological and cosmochemical studies suggest Earth's core is primarily composed of iron with ~5 to 10 wt% nickel and some light elements [e.g., 1]. Therefore, understanding the behavior of Fe-Ni alloys at high pressure is important for interpreting seismic data and for modeling the interior of the Earth. While many studies have investigated the properties of pure Fe at high pressure, the elastic and vibrational properties of Fe-Ni alloys at high pressure are not well known. We measured sound velocities and thermodynamic properties of 95%-enriched 57Fe alloyed with 10 wt% Ni at high-pressures in a Ne pressure medium. Measurements of high statistical quality were performed with nuclear resonant inelastic x-ray scattering (NRIXS) at 3ID-B of the Advanced Photon Source [e.g., 2 & 3]. The sample volume was determined at each compression point with in-line x-ray diffraction at 3ID-B before and after each NRIXS measurement. In this contribution, we will present derived partial phonon density of states, Debye sound velocities, and compressional and shear sound velocities for Fe0.9-Ni0.1 at high-pressures. [1] McDonough, W.F. (2004): Compositional Model for the Earth's Core. Elsevier Ltd., Oxford. [2] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Melting and thermal pressure of hcp-Fe from the phonon density of states, Phys. Earth Planet. Int., doi:10.1016/j.pepi.2011.07.001. [3] Murphy, C.A., J.M. Jackson, W. Sturhahn, and B. Chen (2011): Grüneisen parameter of hcp-Fe to 171 GPa, Geophys. Res. Lett., doi:10.1029/2011GL049531.

  1. Homologous recombination contributes to the repair of DNA double-strand breaks induced by high-energy iron ions

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Faria; Seidler, Sara B.; Kronenberg, Amy; Schild, David; Wiese, Claudia

    2010-06-29

    To test the contribution of homologous recombinational repair (HRR) in repairing DNA damaged sites induced by high-energy iron ions, we used: (1) HRR-deficient rodent cells carrying a deletion in the RAD51D gene and (2) syngeneic human cells impaired for HRR by RAD51D or RAD51 knockdown using RNA interference. We show that in response to iron ions, HRR contributes to cell survival in rodent cells, and that HRR-deficiency abrogates RAD51 foci formation. Complementation of the HRR defect by human RAD51D rescues both enhanced cytotoxicity and RAD51 foci formation. For human cells irradiated with iron ions, cell survival is decreased, and, in p53 mutant cells, the levels of mutagenesis are increased when HRR is impaired. Human cells synchronized in S phase exhibit more pronounced resistance to iron ions as compared with cells in G1 phase, and this increase in radioresistance is diminished by RAD51 knockdown. These results implicate a role for RAD51-mediated DNA repair (i.e. HRR) in removing a fraction of clustered lesions induced by charged particle irradiation. Our results are the first to directly show the requirement for an intact HRR pathway in human cells in ensuring DNA repair and cell survival in response to high-energy high LET radiation.

  2. Cellular iron transport.

    Science.gov (United States)

    Garrick, Michael D; Garrick, Laura M

    2009-05-01

    Iron has a split personality as an essential nutrient that also has the potential to generate reactive oxygen species. We discuss how different cell types within specific tissues manage this schizophrenia. The emphasis in enterocytes is on regulating the body's supply of iron by regulating transport into the blood stream. In developing red blood cells, adaptations in transport manage the body's highest flux of iron. Hepatocytes buffer the body's stock of iron. Macrophage recycle the iron from effete red cells among other iron management tasks. Pneumocytes provide a barrier to prevent illicit entry that, when at risk of breaching, leads to a need to handle the dangers in a fashion essentially shared with macrophage. We also discuss or introduce cell types including renal cells, neurons, other brain cells, and more where our ignorance, currently still vast, needs to be removed by future research.

  3. Disturbance of iron metabolism in brain and Alzheimer's disease%脑铁代谢紊乱与阿尔茨海默病

    Institute of Scientific and Technical Information of China (English)

    符敬坦; 王璞; 郭闯

    2013-01-01

    脑内铁代谢的异常和其所致的氧化应激与阿尔茨海默病(Alzheimer's disease,AD)的发病有关.AD是常见于老年人的一种神经退行性疾病,其特征性的病理改变主要是脑内神经细胞外β-淀粉样蛋白(β-amyloid,Aβ)的沉积形成老年斑(senile plague,SP)、胞内神经原纤维缠结(neurofibrillary tangles,NFTs)和胆碱能神经元丢失.研究证实,在普通老年人和AD患者脑内有铁沉积增多的趋势,且铁等过渡金属离子与APP、Aβ和Tau蛋白密切相关,提示铁可能参与了AD的发病和进展等病理生理过程.因此,深入探讨铁在AD发病中可能的作用,有利于了解AD的发病机制,从而为AD疾病的治疗提供新的靶点.%The dysregulation of iron homeostasis and consequential induction of oxidative stress in the brain were related to the pathogenesis of Alzheimer's disease(AD). AD is a neurodegenerative disease often occurred in the old stage, with main pathologically features of the extracellular β-amyloid (A β) plaques, intracellular neurofibrillary tangles (NFTs) and selective cholinergic neuronal loss in the brain. Recent studies have shown that Tau, APP and its proteolytic product A β are associated with metal homeostasis in the AD brain, suggesting that exposure to metals may potentially modulate AD pathology, either triggering or ameliorating disease progression. Exploring the effect of iron on the pathogenesis of AD may provide a new target for the prevention and treatment of AD.

  4. Thyroid hormone-dependent formation of a subcortical band heterotopia (SBH) in the neonatal brain is not exacerbated under conditions of low dietary iron (FeD).

    Science.gov (United States)

    Spring, S R; Bastian, T W; Wang, Y; Kosian, P; Anderson, G W; Gilbert, M E

    2016-01-01

    Thyroid hormones (TH) are critical for brain development and insufficiencies can lead to structural abnormalities in specific brain regions. Administration of the goitrogen propylthiouracil (PTU) reduces TH production by inhibiting thyroperoxidase (TPO), an enzyme that oxidizes iodide for the synthesis of TH. TPO activity is iron (Fe)-dependent and dietary iron deficiency (FeD) also reduces circulating levels of TH. We have previously shown that modest degrees of TH insufficiency induced in pregnant rat dams alters the expression of TH-responsive genes in the cortex and hippocampus of the neonate, and results in the formation of a subcortical band heterotopia (SBH) in the corpus callosum (Royland et al., 2008, Bastian et al., 2014, Gilbert et al., 2014). The present experiment investigated if FeD alone was sufficient to induce a SBH or if FeD would augment SBH formation at lower doses of PTU. One set of pregnant rats was administered 0, 1, 3, or 10ppm of PTU via drinking water starting on gestational day (GD) 6. FeD was induced in a 2nd set of dams beginning on GD2. A third set of dams received the FeD diet from GD2 paired with either 1ppm or 3ppm PTU beginning on GD6. All treatments continued until the time of sacrifice. On PN18, one female pup from each litter was sacrificed and the brain examined for SBH. We observed lower maternal, PN2 and PN18 pup serum T4 in response to PTU. FeD reduced serum T4 in pups on PN16, but did not affect serum T4 in dams or PN2 pups. Neither did FeD in combination with PTU alter T4 levels in dams on PN18 or pups on PN2 compared to PTU treatment alone. By PN16, however more severe T4 reductions were observed in pups when FeD was combined with PTU. SBH increased with increasing dosage of PTU, but counter to our hypothesis, no SBH was detected in the offspring of FeD dams. As such, T4 levels in dams and newborn pups rather than older neonates appear to be a better predictor SBH associated with TH insufficiency. These data indirectly

  5. Acute high-altitude hypoxic brain injury Identification of ten differential proteins

    Institute of Scientific and Technical Information of China (English)

    Jianyu Li; Yuting Qi; Hui Liu; Ying Cui; Li Zhang; Haiying Gong; Yaxiao Li; Lingzhi Li; Yongliang Zhang

    2013-01-01

    Hypobaric hypoxia can cause severe brain damage and mitochondrial dysfunction, and is involved in hypoxic brain injury. However, little is currently known about the mechanisms responsible for mi-tochondrial dysfunction in hypobaric hypoxic brain damage. In this study, a rat model of hypobaric hypoxic brain injury was established to investigate the molecular mechanisms associated with mi-tochondrial dysfunction. As revealed by two-dimensional electrophoresis analysis, 16, 21, and 36 differential protein spots in cerebral mitochondria were observed at 6, 12, and 24 hours post-hypobaric hypoxia, respectively. Furthermore, ten protein spots selected from each hypobaric hypoxia subgroup were similarly regulated and were identified by mass spectrometry. These de-tected proteins included dihydropyrimidinase-related protein 2, creatine kinase B-type, isova-leryl-CoA dehydrogenase, elongation factor Ts, ATP synthase beta-subunit, 3-mercaptopyruvate sulfurtransferase, electron transfer flavoprotein alpha-subunit, Chain A of 2-enoyl-CoA hydratase, NADH dehydrogenase iron-sulfur protein 8 and tropomyosin beta chain. These ten proteins are al involved in the electron transport chain and the function of ATP synthase. Our findings indicate that hypobaric hypoxia can induce the differential expression of several cerebral mitochondrial proteins, which are involved in the regulation of mitochondrial energy production.

  6. High critical currents in iron-clad superconducting MgB2 wires.

    Science.gov (United States)

    Jin, S; Mavoori, H; Bower, C; van Dover, R B

    2001-05-31

    Technically useful bulk superconductors must have high transport critical current densities, Jc, at operating temperatures. They also require a normal metal cladding to provide parallel electrical conduction, thermal stabilization, and mechanical protection of the generally brittle superconductor cores. The recent discovery of superconductivity at 39 K in magnesium diboride (MgB2) presents a new possibility for significant bulk applications, but many critical issues relevant for practical wires remain unresolved. In particular, MgB2 is mechanically hard and brittle and therefore not amenable to drawing into the desired fine-wire geometry. Even the synthesis of moderately dense, bulk MgB2 attaining 39 K superconductivity is a challenge because of the volatility and reactivity of magnesium. Here we report the successful fabrication of dense, metal-clad superconducting MgB2 wires, and demonstrate a transport Jc in excess of 85,000 A cm-2 at 4.2 K. Our iron-clad fabrication technique takes place at ambient pressure, yet produces dense MgB2 with little loss of stoichiometry. While searching for a suitable cladding material, we found that other materials dramatically reduced the critical current, showing that although MgB2 itself does not show the 'weak-link' effect characteristic of the high-Tc superconductors, contamination does result in weak-link-like behaviour.

  7. Observation of High Iron Charge States at Low Energies in Solar Energetic Particle Events

    Science.gov (United States)

    Guo, Z.; Möbius, E.; Klecker, B.; Bochsler, P.; Connell, J. J.; Kartavykh, Y. Y.; Mason, G. M.; Popecki, M. A.

    2014-04-01

    The ionic charge states of solar energetic particles (SEPs) provide direct information about the source plasma, the acceleration environment, and their transport. Recent studies report that both gradual and impulsive SEP events show mean iron charge states langQ Ferang ~ 10-14 at low energies E nuc-1, consistent with their origin from typical corona material at temperatures 1-2 MK. Observed increases of langQ Ferang up to 20 at energies 0.1-0.5 MeV nuc-1 in impulsive SEPs are attributed to stripping during acceleration. However, Q Fe > 16 is occasionally found in the solar wind, particularly coming from active regions, in contrast to the exclusively reported langQ Ferang = 14 throughout the entire SEPICA and STOF energy range have been identified. Four of the nine events are impulsive events identified through velocity dispersion that are consistent with source temperatures >=2 MK up to ~4 MK. The other five events show evidence of interplanetary acceleration. Four of them involve re-acceleration of impulsive material, whose original energy dependent charge states appear re-distributed to varying extent bringing higher charge states to lower energy. One event, which shows flat but elevated langQ Ferang ~ 14.2 over the entire energy range, can be associated with interplanetary acceleration of high temperature material. This event may exemplify a rare situation when a second shock plows through high temperature coronal mass ejection material.

  8. Simple-Cubic Carbon Frameworks with Atomically Dispersed Iron Dopants toward High-Efficiency Oxygen Reduction.

    Science.gov (United States)

    Wang, Biwei; Wang, Xinxia; Zou, Jinxiang; Yan, Yancui; Xie, Songhai; Hu, Guangzhi; Li, Yanguang; Dong, Angang

    2017-03-08

    Iron and nitrogen codoped carbons (Fe-N-C) have attracted increasingly greater attention as electrocatalysts for oxygen reduction reaction (ORR). Although challenging, the synthesis of Fe-N-C catalysts with highly dispersed and fully exposed active sites is of critical importance for improving the ORR activity. Here, we report a new type of graphitic Fe-N-C catalysts featuring numerous Fe single atoms anchored on a three-dimensional simple-cubic carbon framework. The Fe-N-C catalyst, derived from self-assembled Fe3O4 nanocube superlattices, was prepared by in situ ligand carbonization followed by acid etching and ammonia activation. Benefiting from its homogeneously dispersed and fully accessible active sites, highly graphitic nature, and enhanced mass transport, our Fe-N-C catalyst outperformed Pt/C and many previously reported Fe-N-C catalysts for ORR. Furthermore, when used for constructing the cathode for zinc-air batteries, our Fe-N-C catalyst exhibited current and power densities comparable to those of the state-of-the-art Pt/C catalyst.

  9. High critical currents in iron-clad superconducting MgB2 wires

    Science.gov (United States)

    Jin, S.; Mavoori, H.; Bower, C.; van Dover, R. B.

    2001-05-01

    Technically useful bulk superconductors must have high transport critical current densities, Jc, at operating temperatures. They also require a normal metal cladding to provide parallel electrical conduction, thermal stabilization, and mechanical protection of the generally brittle superconductor cores. The recent discovery of superconductivity at 39K in magnesium diboride (MgB2) presents a new possibility for significant bulk applications, but many critical issues relevant for practical wires remain unresolved. In particular, MgB2 is mechanically hard and brittle and therefore not amenable to drawing into the desired fine-wire geometry. Even the synthesis of moderately dense, bulk MgB2 attaining 39K superconductivity is a challenge because of the volatility and reactivity of magnesium. Here we report the successful fabrication of dense, metal-clad superconducting MgB2 wires, and demonstrate a transport Jc in excess of 85,000Acm-2 at 4.2K. Our iron-clad fabrication technique takes place at ambient pressure, yet produces dense MgB2 with little loss of stoichiometry. While searching for a suitable cladding material, we found that other materials dramatically reduced the critical current, showing that although MgB2 itself does not show the `weak-link' effect characteristic of the high-Tc superconductors, contamination does result in weak-link-like behaviour.

  10. Facile, high efficiency immobilization of lipase enzyme on magnetic iron oxide nanoparticles via a biomimetic coating

    Directory of Open Access Journals (Sweden)

    He Lihong

    2011-06-01

    Full Text Available Abstract Background Immobilization of lipase on appropriate solid supports is one way to improve their stability and activity, and can be reused for large scale applications. A sample, cost- effective and high loading capacity method is still challenging. Results A facile method of lipase immobilization was developed in this study, by the use of polydopamine coated magnetic nanoparticles (PD-MNPs. Under optimal conditions, 73.9% of the available lipase was immobilized on PD-MNPs, yielding a lipase loading capacity as high as 429 mg/g. Enzyme assays revealed that lipase immobilized on PD-MNPs displayed enhanced pH and thermal stability compared to free lipase. Furthermore, lipase immobilized on PD-MNPs was easily isolated from the reaction medium by magnetic separation and retained more than 70% of initial activity after 21 repeated cycles of enzyme reaction followed by magnetic separation. Conclusions Immobilization of enzyme onto magnetic iron oxide nanoparticles via poly-dopamine film is economical, facile and efficient.

  11. Effect of Ti-V-Nb-Mo addition on microstructure of high chromium cast iron

    Directory of Open Access Journals (Sweden)

    Ma Youping

    2012-05-01

    Full Text Available The effects of trace additions of multi-alloying elements (Ti, Nb, V, Mo on carbides precipitation and as-cast microstructure of eutectic high chromium cast iron containing 2.85wt.%C and 31.0wt.%Cr were investigated from thermodynamic and kinetic considerations. The thermodynamic calculations show that Ti and Nb exist in the multi-alloying system in the forms of TiC and NbC. The formation of VC during the solidification is not feasible from the thermodynamic consideration. XRD analysis shows that the V exists in alloy compounds (VCr2C2, VCrFe8. The first precipitated high melting point particles (TiC, NbC can act as the heterogeneous substrate of M7C3 carbides, which results in significant refinement of the M7C3 carbides. After the addition of alloying elements, C atom diffusion is hindered due to the strong affinities of the strong carbide forming elements for carbon, which decreases the growth rate of carbides. The combined roles of the increase of nucleation rate and the decrease of carbides growth rate lead to the finer microstructure.

  12. The plasma membrane proteome of maize roots grown under low and high iron conditions.

    Science.gov (United States)

    Hopff, David; Wienkoop, Stefanie; Lüthje, Sabine

    2013-10-08

    Iron (Fe) homeostasis is essential for life and has been intensively investigated for dicots, while our knowledge for species in the Poaceae is fragmentary. This study presents the first proteome analysis (LC-MS/MS) of plasma membranes isolated from roots of 18-day old maize (Zea mays L.). Plants were grown under low and high Fe conditions in hydroponic culture. In total, 227 proteins were identified in control plants, whereas 204 proteins were identified in Fe deficient plants and 251 proteins in plants grown under high Fe conditions. Proteins were sorted by functional classes, and most of the identified proteins were classified as signaling proteins. A significant number of PM-bound redox proteins could be identified including quinone reductases, heme and copper-containing proteins. Most of these components were constitutive, and others could hint at an involvement of redox signaling and redox homeostasis by change in abundance. Energy metabolism and translation seem to be crucial in Fe homeostasis. The response to Fe deficiency includes proteins involved in development, whereas membrane remodeling and assembly and/or repair of Fe-S clusters is discussed for Fe toxicity. The general stress response appears to involve proteins related to oxidative stress, growth regulation, an increased rigidity and synthesis of cell walls and adaption of nutrient uptake and/or translocation. This article is part of a Special Issue entitled: Plant Proteomics in Europe.

  13. High bioavailablilty iron maize (Zea mays L. developed through molecular breeding provides more absorbable iron in vitro (Caco-2 model and in vivo (Gallus gallus

    Directory of Open Access Journals (Sweden)

    Tako Elad

    2013-01-01

    Full Text Available Abstract Background Iron (Fe deficiency is the most common micronutrient deficiency worldwide. Iron biofortification is a preventative strategy that alleviates Fe deficiency by improving the amount of absorbable Fe in crops. In the present study, we used an in vitro digestion/Caco 2 cell culture model as the guiding tool for breeding and development of two maize (Zea mays L. lines with contrasting Fe bioavailability (ie. Low and High. Our objective was to confirm and validate the in vitro results and approach. Also, to compare the capacities of our two maize hybrid varieties to deliver Fe for hemoglobin (Hb synthesis and to improve the Fe status of Fe deficient broiler chickens. Methods We compared the Fe-bioavailability between these two maize varieties with the presence or absence of added Fe in the maize based-diets. Diets were made with 75% (w/w maize of either low or high Fe-bioavailability maize, with or without Fe (ferric citrate. Chicks (Gallus gallus were fed the diets for 6 wk. Hb, liver ferritin and Fe related transporter/enzyme gene-expression were measured. Hemoglobin maintenance efficiency (HME and total body Hb Fe values were used to estimate Fe bioavailability from the diets. Results DMT-1, DcytB and ferroportin expressions were higher (P  Conclusions We conclude that the High Fe-bioavailability maize contains more bioavailable Fe than the Low Fe-bioavailability maize, presumably due to a more favorable matrix for absorption. Maize shows promise for Fe biofortification; therefore, human trials should be conducted to determine the efficacy of consuming the high bioavailable Fe maize to reduce Fe deficiency.

  14. Iron titanium phosphates as high-specific-capacity electrode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Essehli, R., E-mail: essehli.rachid@yahoo.fr [Laboratory of Mineral Solid and Analytical Chemistry (LMSAC), Department of Chemistry, Faculty of Sciences, University Mohamed I, PO. Box 717, 60000 Oujda (Morocco); ESECO SYSTEMS 270 rue Thomas Edison, Atelier Relais No 6, 34400 Lunel (France); El Bali, B. [Laboratory of Mineral Solid and Analytical Chemistry (LMSAC), Department of Chemistry, Faculty of Sciences, University Mohamed I, PO. Box 717, 60000 Oujda (Morocco); Faik, A. [CIC energigune, Parque Tecnológico de Álava, Albert Einstein 48, 01510 Miñano, Álava (Spain); Naji, M. [CNRS, UPR3079 CEMHTI, 1D avenue de la Recherche Scientifique, 45071 Orléans cedex 2 (France); Benmokhtar, S. [LCPGM, Laboratoire de Chimie-Physique Générale des Matériaux, Département de Chimie, Université Hassan II-Mohammedia, Faculté des Sciences Ben M’Sik, Casablanca (Morocco); Zhong, Y.R.; Su, L.W.; Zhou, Z. [Institute of New Energy Material Chemistry, Synergetic Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071 (China); Kim, J.; Kang, K. [Department of Materials Science and Engineering, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Dusek, M. [Institute of Physics of the ASCR, v.v.i., Na Slovance 2, 182 21 Praha 8 (Czech Republic)

    2014-02-05

    Highlights: • Iron Titanium Phosphates as High-Specific-Capacity. • Electrode Materials for Lithium ion Batteries. • During the following cycles, good reversible capacity retention and better cyclabilit. • Ex-situ XRD analysis during the first discharge shows an amorphization of this anode material. -- Abstract: Two iron titanium phosphates, Fe{sub 0.5}TiOPO{sub 4} and Fe{sub 0.5}Ti{sub 2}(PO{sub 4}){sub 3}, were prepared, and their crystal structures and electrochemical performances were compared. The electrochemical measurements of Fe{sub 0.5}TiOPO{sub 4} as an anode of a lithium ion cell showed that upon the first discharge down to 0.5 V, the cell delivered a capacity of 560 mA h/g, corresponding to the insertion of 5 Li’s per formula unit Fe{sub 0.5}TiOPO{sub 4}. Ex-situ XRD reveals a gradual evolution of the structure during cycling of the material, with lower crystallinity after the first discharge cycle. By correlating the electrochemical performances with the structural studies, new insights are achieved into the electrochemical behaviour of the Fe{sub 0.5}TiOPO{sub 4} anode material, suggesting a combination of intercalation and conversion reactions. The Nasicon-type Fe{sub 0.5}Ti{sub 2}(PO{sub 4}){sub 3} consists of a three-dimensional network made of corners and edges sharing [TiO{sub 6}] and [FeO{sub 6}] octahedra and [PO{sub 4}] tetrahedra leading to the formation of trimmers [FeTi{sub 2}O{sub 12}]. The first discharge of lithium ion cells based on Fe{sub 0.5}Ti{sub 2}(PO{sub 4}){sub 3} materials showed electrochemical activity of Ti{sup 4+}/Ti{sup 3+} and Fe{sup 2+}/Fe{sup 0} couples in the 2.5–1 V region. Below this voltage, the discharge profiles are typical of phosphate systems where Li{sub 3}PO{sub 4} is a product of the electrochemical reaction with lithium; moreover, the electrolyte solvent is reduced. An initial capacities as high as 1100 mA h g{sup −1} can be obtained at deep discharge. However, there is an irreversible capacity

  15. Influence of rare earth nanoparticles and inoculants on performance and microstructure of high chromium cast iron

    Institute of Scientific and Technical Information of China (English)

    HOU Yuncheng; WANG You; PAN Zhaoyi; YU Lili

    2012-01-01

    The high chromium cast irons (HCCIs) with rare earth (RE) nanoparticles or inoculants were fabricated in the casting process.The phase compositions and microstructure were analyzed by X-ray diffraction (XRD) and optical microscopy (OM),respectively.The hardness and impact toughness were tested by Rockwel-hardmeter and impacting test enginery.And then,the morphology of fracture was researched by scanning electron microscopy (SEM).The results demonstrated that the phase compositions of HCCIs with addition of RE nanoparticles or inoculants which were M7C3 carbides + α -Fe did not change obviously.However,the prime M7C3 carbides morphology had great changes with the increase of RE nanoparticles,which changed from long lath to granular or island shape.When the content of RE nanoparticles was 0.4 wt.%,the microstructure of high chromium cast iron was refined greatly.The microstructure of carbides was coarser when the addition of RE nanoparticles was higher than 0.4 wt.%.The hardness and impact toughness of HCCIs were improved by addition of RE nanoparticles or inoculants.The impact toughness of HCCIs was increased 36.4% with RE nanoparticles of 0.4 wt.%,but the hardness changed slightly.In addition,the adding of RE nanoparticles or inoculants could reduce the degree of the brittle fracture.Fracture never seemed regular,instead,containing lots of laminates and dimples with the increase of the RE nanoparticles.The results also indicated that the optimal addition amonnt of the RE nanoparticles was 0.4%,under this composition,the microstructure and mechanical property achieved the best cooperation.In addition,through the study of erosion wear rate,when adding 0.4% RE nanoparticles into the HCCIs,the erosion wear rate got the minimum 0.32×10-3 g/mm2,which could increase 51.5% compared with that without any RE nanoparticles.

  16. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation

    NARCIS (Netherlands)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, Georgios

    2016-01-01

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction

  17. A High-Resolution In Vivo Atlas of the Human Brain's Serotonin System

    DEFF Research Database (Denmark)

    Beliveau, Vincent; Ganz, Melanie; Feng, Ling

    2017-01-01

    associations between protein expression and density at high detail. This new in vivo neuroimaging atlas of the 5-HT system not only provides insight in the human brain's regional protein synthesis, transport, and density, but also represents a valuable source of information for the neuroscience community......The serotonin (5-hydroxytryptamine, 5-HT) system modulates many important brain functions and is critically involved in many neuropsychiatric disorders. Here, we present a high-resolution, multidimensional, in vivo atlas of four of the human brain's 5-HT receptors (5-HT1A, 5-HT1B, 5-HT2A, and 5-HT4...... brain by comparing the 5-HT density across the atlas with data from the Allen Human Brain atlas and identified receptor- and transporter-specific associations that show the regional relation between the two measures. Together, these data provide unparalleled insight into the serotonin system...

  18. Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers

    Science.gov (United States)

    Wood, Deborah; Crocket, Kirsty; Brand, Tim; Stutter, Marc; Wilson, Clare; Schröder, Christian

    2016-04-01

    Linking carbon and iron cycles by investigating transport, fate and mineralogy of iron-bearing colloids from peat-draining rivers - Scotland as model for high-latitude rivers Wood, D.A¹, Crocket, K², Brand, T², Stutter, M³, Wilson, C¹ & Schröder, C¹ ¹Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA ²Scottish Association for Marine Science, University of the Highlands and Islands, Dunbeg, Oban, PA37 1QA ³James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH The biogeochemical iron cycle exerts significant control on the carbon cycle¹. Iron is a limiting nutrient in large areas of the world's oceans and its bioavailability controls CO2 uptake by marine photosynthesizing microorganisms. While atmospheric iron inputs to the open ocean have been extensively measured, global river inputs have likely been underestimated because most major world rivers exhibit extensive iron removal by flocculation and sedimentation during seawater mixing. Iron minerals and organic matter mutually stabilise each other², which results in a 'rusty carbon sink' in sediments³ on the one hand but may also enhance transport beyond the salinity gradient on the other. Humic-rich, high latitude rivers have a higher iron-carrying capacity⁴-⁶ but are underrepresented in iron flux calculations. The West Coast sea lochs in Scotland are fed by predominantly peatland drainage catchments, and the rivers entering the sea lochs carry a high load of organic matter. The short distance between many of these catchments and the coastal ocean facilitates source-to-sea research investigating transport, fate and mineralogy of iron-bearing colloids providing a good analogue for similar high latitude fjordic systems. We use SeaFAST+ICP-MS and Mössbauer spectroscopy to survey trace metal concentrations, with emphasis on iron concentrations, speciation and mineralogy, across salinity gradients. In combination with ultra-filtration techniques, this allows

  19. Unusual calibration curves observed for iron using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Welz, Bernhard, E-mail: w.bernardo@terra.com.b [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Instituto Nacional de Ciencia e Tecnologia do CMPq-INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador-BA (Brazil); Santos, Lisia M.G. dos [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Instituto Nacional de Controle de Qualidade em Saude-INCQS-Fiocruz, 21040-900 Rio de Janeiro-RJ (Brazil); Araujo, Rennan G.O. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Departamento de Quimica, Universidade Federal de Sergipe, 49100-000 Sao Cristovao-SE (Brazil); Jacob, Silvana do C. [Instituto Nacional de Controle de Qualidade em Saude-INCQS-Fiocruz, 21040-900 Rio de Janeiro-RJ (Brazil); Vale, Maria Goreti R. [Instituto Nacional de Ciencia e Tecnologia do CMPq-INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador-BA (Brazil); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre-RS (Brazil); Okruss, Michael; Becker-Ross, Helmut [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-Department Berlin, 12489 Berlin (Germany)

    2010-03-15

    The simultaneous determination of cadmium and iron in plant and soil samples has been investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry. The primary cadmium resonance line at 228.802 nm and an adjacent secondary iron line at 228.726 nm, which is within the spectral interval covered by the charge-coupled device (CCD) array detector, have been used for the investigations. Due to the very high iron content in most of the soil samples the possibility has been investigated to reduce the sensitivity and extend the working range by using side pixels for measurement at the line wings instead of the line core. It has been found that the calibration curves measured at all the analytically useful pixels of this line consisted of two linear parts with distinctly different slopes. This effect has been independent of the positioning of the wavelength, i.e., if the Cd line or the Fe line was in the center of the CCD array. The most likely explanation for this unusual behavior is a significant difference between the instrument width DELTAlambda{sub Instr} and the absorption line width DELTAlambda{sub Abs}, which is quite pronounced in the case of Fe. Using both parts of the calibration curves and simultaneous measurement at the line center and at the wings made it possible to extend the working range for the iron determination to more than three orders of magnitude.

  20. Application of magnetic resonance spectroscopy in the differentiation of high-grade brain neoplasm and inflammatory brain lesions

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz-Filho, Jose Roberto Lopes; Santana-Netto, Pedro Vieira; Sgnolf, Aline [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Image Dept.], e-mail: jrl.ferraz@terra.com.br; Rocha-Filho, Jose Alves; Mauad, Fernando [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Radiology Dept.; Sanches, Rafael Angelo [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Imaging Dept.

    2009-06-15

    This study aims at evaluating the application of magnetic resonance spectroscopy (MRS) in the differential diagnosis of brain tumors and inflammatory brain lesions. The examinations of 81 individuals, who performed brain MRS and were retrospectively analyzed. The patients with ages between 10 and 80 years old, were divided into two groups. Group A consisted of 42 individuals with diagnoses of cerebral toxoplasmosis and Group B was formed of 39 individuals with diagnosis of glial neoplasms. On analyzing the ROC curve, the discriminatory boundary for the Cho/Cr ratio between inflammatory lesions and tumors was 1.97 and for the NAA/Cr ratio it was 1.12. RMS is an important method useful in the distinction of inflammatory brain lesions and high-degree tumors when the Cho/Cr ratio is greater than 1.97 and the NAA/Cr ratio is less than 1.12. And so this method is important in the planning of treatment and monitoring of the therapeutic efficiency. (author)

  1. An efficient and highly versatile synthetic route to prepare iron oxide nanoparticles/nanocomposites with tunable morphologies.

    Science.gov (United States)

    Karagoz, Bunyamin; Yeow, Jonathan; Esser, Lars; Prakash, Shyam M; Kuchel, Rhiannon P; Davis, Thomas P; Boyer, Cyrille

    2014-09-02

    We report a versatile synthetic method for the in situ self-assembly of magnetic-nanoparticle-functionalized polymeric nanomorphologies, including spherical micelles and rod-like and worm-like micelles and vesicles. Poly(oligoethylene glycol methacrylate)-block-(methacrylic acid)-block-poly(styrene) (POEGMA-b-PMAA-b-PST) triblock copolymer chains were simultaneously propagated and self-assembled via a polymerization-induced self-assembly (PISA) approach. Subsequently, the carboxylic acid groups in the copolymers were used to complex an iron ion (Fe(II)/Fe(III)) mixture. Iron oxide nanoparticles were then formed in the central block, within the polymeric nanoparticles, via alkaline coprecipitation of the iron(II) and (III) salts. Nanoparticle morphologies, particle sizes, molecular weights, and chemical structures were then characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), size exclusion chromatography (SEC), and (1)H NMR measurements. TEM micrographs showed that the average size of the magnetic nanoparticles was ∼7 nm at the hydrophobic/hydrophilic nexus contained within the nanoparticles. In addition, XRD was used to confirm the formation of iron oxide nanoparticles. Importantly, the polymeric nanoparticle morphologies were not affected by the coprecipitation of the magnetic nanoparticles. The hybrid nanoparticles were then evaluated as negative MRI contrast agents, displaying remarkably high transverse relaxivities (r2, greater than 550 mM(-1) s(-1) at 9.4 T); a result, that we hypothesize, ensues from iron oxide nanoparticle clustering at the hydrophobic-hydrophilic interface. This simple synthetic procedure is highly versatile and produces nanocarriers of tunable size and shape with high efficacy as MRI contrast agents and potential utility as theranostic delivery vectors.

  2. INFLUENCE OF IMPULSE MAGNETIC FIELD ON GRAPHITE MORPHOLOGY OF HIGH-ALLOY IRON

    Directory of Open Access Journals (Sweden)

    A. G. Anisovich

    2011-01-01

    Full Text Available The results of researches of change of microstructure of heavily alloyed austenitic cast-iron ChN1507 subjected to magnetoimpulse processing are given. It is established that microhardness rises on all section of the sample.

  3. Schoolchildren with Learning Difficulties Have Low Iron Status and High Anemia Prevalence

    Science.gov (United States)

    Arcanjo, C. P. C.; Santos, P. R.

    2016-01-01

    Background. In developing countries there is high prevalence of iron deficiency anemia, which reduces cognitive performance, work performance, and endurance; it also causes learning difficulties and negative impact on development for infant population. Methods. The study concerns a case-control study; data was collected from an appropriate sample consisting of schoolchildren aged 8 years. The sample was divided into two subgroups: those with deficient initial reading skills (DIRS) (case) and those without (control). Blood samples were taken to analyze hemoglobin and serum ferritin levels. These results were then used to compare the two groups with Student's t-test. Association between DIRS and anemia was analyzed using odds ratio (OR). Results. Hemoglobin and serum ferritin levels of schoolchildren with DIRS were statistically lower when compared to those without, hemoglobin p = 0.02 and serum ferritin p = 0.04. DIRS was statistically associated with a risk of anemia with a weighted OR of 1.62. Conclusions. In this study, schoolchildren with DIRS had lower hemoglobin and serum ferritin levels when compared to those without. PMID:27703806

  4. Microstructure and properties of Ti–Nb–V–Mo-alloyed high chromium cast iron

    Indian Academy of Sciences (India)

    Youping Ma; Xiulan Li; Yugao Liu; Shuyi Zhou; Xiaoming Dang

    2013-10-01

    The correlations of microstructure, hardness and fracture toughness of high chromium cast iron with the addition of alloys (titanium, vanadium, niobium and molybdenum) were investigated. The results indicated that the as-cast microstructure changed from hypereutectic, eutectic to hypoeutectic with the increase of alloy contents. Mo dissolved in austenite and increased the hardness by solid solution strengthening. TiC and NbC mainly existed in austenite and impeded the austenite dendrite development. V existed in multicomponent systems in forms of V alloy compounds (VCrFe8 and VCr2C2).With the increase of alloy additions, carbides size changed gradually from refinement to coarseness, hardness and impact toughness were increased and then decreased. Compared with the fracture toughness (6 J/cm2) and hardness (50.8HRC) without any alloy addition, the toughness and hardness at 0.60 V–0.60Ti–0.60Nb–0.35Mo (wt%) additions were improved and achieved to 11 J/cm2 and 58.9HRC, respectively. The synergistic roles of Ti, Nb, V and Mo influenced the solidification behaviour of alloy. The refinement of microstructure and improvement of carbides morphologies, size and distribution improved the impact toughness.

  5. Effects of Si on the Microstructures and Mechanical Properties of High-Chromium Cast Iron

    Science.gov (United States)

    Lai, J. P.; Pan, Q. L.; Peng, H. J.; Cui, H. R.; Xiao, C. A.

    2016-11-01

    Effect of Si on the microstructures and mechanical properties of high-chromium cast iron was investigated. The eutectic carbides are refined greatly and a transformation of matrix from austenitic matrix to pearlite is observed with increase in Si content from 0.5 to 1.5 wt.%. The refinement of eutectic microstructure is attributed to the decrease in the eutectic temperature, while the transformation from austenite matrix to pearlite is associated with the increase in solubility of carbon in the matrix. In the pearlite matrix, two types of pearlite are observed: one with lamellar pearlite, distributing at the periphery, and the second one with granular pearlite at the center. The density of secondary carbides precipitated from the matrix increases greatly with addition of Si from 0.5 to 1.5 wt.%, which is associated with more carbon and chromium elements confined in the matrix in the alloy containing 1.5 wt.%. More rod-like particles are observed in the alloy containing 0.5 wt.% Si, while the morphology of secondary carbides of alloy containing 1.5 wt.% is granular. The mechanical properties are improved with a 7% increase in tensile strength from 586 to 626 MPa and impact toughness from 5.8 to 7.3 J cm-2.

  6. X-Ray Absorption Spectroscopic Studies of High-Spin Nonheme (Alkylperoxo)Iron(III) Intermediates

    Energy Technology Data Exchange (ETDEWEB)

    Shan, X.; Rohde, J.-U.; Koehntop, K.D.; Zhou, Y.; Bukowski, M.R.; Costas, M.; Fujisawa, K.; Que, L.; Jr.

    2009-06-04

    The reactions of iron(II) complexes [Fe(Tp{sup t-Bu,i-Pr})(OH)] (1a, Tp{sup t-Bu,i-Pr} = hydrotris(3-tert-butyl-5-isopropyl-1-pyrazolyl)borate), [Fe(6-Me{sub 2}BPMCN)(OTf){sub 2}] (1b, 6-Me{sub 2}BPMCN = N,N'-bis((2-methylpyridin-6-yl)methyl)-N,N'-dimethyl-trans-1,2-diaminocyclohexane), and [Fe(L{sup 8}Py{sub 2})(OTf)](OTf) (1c, L{sup 8}Py{sub 2} = 1,5-bis(pyridin-2-ylmethyl)-1,5-diazacyclooctane) with tert-BuOOH give rise to high-spin Fe{sup III}-OOR complexes. X-ray absorption spectra (XAS) of these high-spin species show characteristic features, distinct from those of low-spin Fe-OOR complexes (Rohde, J.-U.; et al. J. Am. Chem. Soc. 2004, 126, 16750--16761). These include (1) an intense 1s {yields} 3d preedge feature, with an area around 20 units, (2) an edge energy, ranging from 7122 to 7126 eV, that is affected by the coordination environment, and (3) a 1.86--1.96 {angstrom} Fe-OOR bond, compared to the 1.78 {angstrom} Fe-OOR bond in low-spin complexes. These unique features likely arise from a flexible first coordination sphere in those complexes. The difference in Fe-OOR bond length may rationalize differences in reactivity between low-spin and high-spin Fe{sup III}-OOR species.

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

    Science.gov (United States)

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

    2016-06-10

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

  8. Microstructure and Property of Hypereutectic High Chromium Cast Iron Prepared by Slope Cooling Body-Centrifugal Casting Method

    Institute of Scientific and Technical Information of China (English)

    Zhifu HUANG; Jiandong XING; Anfeng ZHANG

    2006-01-01

    In this paper, the ring-type ingot of hypereutectic high Cr cast iron was obtained by slope cooling bodycentrifugal casting method (SC-CCM), and its microstructure and impact toughness were investigated, respectively. The results indicated that, first, the primary carbides in the microstructure are prominently finer than those in the hypereutectic high Cr cast iron prepared by conventional casting method. Second, in the ring-type ingot, the primary carbides near radial outer field are finer than those near radial inner field; furthermore, there is dividing field in the microstructure. Finally, the impact toughness values of the specimens impacted on the radial outer face and on the radial inner face are improved respectively about 36% and 138%more than that of the hypereutectic high Cr one prepared by conventional casting method.

  9. Acquistion of High Resolution Electroencephalogram Systems for Advancing Brain-Machine Interaction Research

    Science.gov (United States)

    2015-12-21

    SECURITY CLASSIFICATION OF: The goal of this project is to acquire high performance Electroencephalogram (EEG) systems that enable real-time...measurement of human brain activities at high spatial-temporal resolution in both laboratory and real-life environments. Our long-term vision is to develop...state-of-the-art Biosemi Active Two EEG device to enable real-time measurement of brain 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13

  10. High performance nanobio photocatalyst for targeted brain cancer therapy.

    Energy Technology Data Exchange (ETDEWEB)

    Rozhkova, E.; Ulasov, I.; Dimitrijevic, N. M.; Lesniak, M.; Rajh, T.; Lai, B.; Center for Nanoscale Materials

    2009-09-01

    We report pronounced and specific antiglioblastoma cell phototoxicity of 5 nm TiO{sub 2} particles covalently tethered to an antibody via a dihydroxybenzene bivalent linker. The linker application enables absorption of a visible part of the solar spectrum by the nanobio hybrid. The phototoxicity is mediated by reactive oxygen species (ROS) that initiate programmed death of the cancer cell. Synchrotron X-ray fluorescence microscopy (XFM) was applied for direct visualization of the nanobioconjugate distribution through a single brain cancer cell at the submicrometer scale.

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

    Science.gov (United States)

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

    2017-10-05

    Flow battery (FB) is one of the most promising stationary energy storage devices for storing renewable energies. However, commercial progress of the FBs is limited by their high cost and low energy density. Here we report a neutral zinc-iron FB with very low cost and high energy density. By using highly soluble FeCl2/ZnBr2 species, a charge energy density of 56.30 Wh/L can be achieved. DFT calculations demonstrated that glycine can combine with iron to suppress hydrolysis and crossover of Fe3+/Fe2+. The results indicated that an energy efficiency of 86.66% can be obtained at 40 mA/cm2 and the battery can run stably for more than 100 cycles. Furthermore, a porous membrane with low cost was employed to lower the capital cost to less than 50 $/kWh, which was the lowest value that has ever been reported. Combining the features of low cost, high energy density and high energy efficiency, the neutral zinc-iron FB becomes a promising candidate for stationary energy storage applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kozubal, Mark; Romine, Margaret F.; Jennings, Ryan; Jay, Z.; Tringe, Susannah G.; Rusch, Douglas B.; Beam, Jake; McCue, Lee Ann; Inskeep, William P.

    2013-03-01

    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 indicate that the replicate assemblies represent a new 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.

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

    Science.gov (United States)

    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

    2013-03-01

    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.

  14. Ocean iron cycle

    Science.gov (United States)

    Boyd, Philip W.

    Interest in the biogeochemical cycle of iron has grown rapidly over the last two decades, due to the potential role of this element in modulating global climate in the geological past and ocean productivity in the present day. This trace metal has a disproportionately large effect (1 × 105 C:Fe) on photosynthetic carbon fixation by phytoplankton. In around one third of the open ocean, so-called high-nitrate low-chlorophyll (HNLC) regions, the resident phytoplankton have low growth rates despite an abundance of plant nutrients. This is due to the low supply of iron. Iron is present in the ocean in three phases, dissolved, colloidal, and particulate (biogenic and lithogenic). However, iron chemistry is complex with interactions between chemistry and biology such as the production of iron-binding siderophores by oceanic bacteria. This results in the interplay of inorganic chemistry, photochemistry, and organic complexation. Sources of new iron include dust deposition, upwelling of iron-rich deep waters, and the resuspension and lateral transport of sediments. Sinks for iron are mainly biological as evidenced by the vertical nutrient-like profile for dissolved iron in the ocean. Iron is rapidly recycled by the upper ocean biota within a so-called "ferrous wheel." The fe ratio [(new iron)/(new + regenerated iron)] provides an index of the relative supply of iron to the biota by new versus recycled iron. Over the last 15 years, interest in the potential role of iron in shaping climate in the geological past resulted in some of the most ambitious experiments in oceanography: large-scale (i.e., 50-1000 km2) iron enrichment of HNLC waters. They have provided valuable insights into how iron supply influences the biogeochemical cycles of elements such as carbon, sulfur, silicon, nitrogen, and phosphate.

  15. In vivo tracing of superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells transplanted for traumatic brain injury by susceptibility weighted imaging in a rat model

    Institute of Scientific and Technical Information of China (English)

    CHENG Jing-liang; YANG Yun-jun; LI Hua-li; WANG Juan; WANG Mei-hao; ZHANG Yong

    2010-01-01

    Objective:To label rat bone marrow mesenchymal stem cells (BMSCs) with superparamagnetic iron oxide (SPIO) in vitro, and to monitor the survival and location of these labeled BMSCs in a rat model of traumatic brain injury (TBI) by susceptibility weighted imaging (SWI)sequence.Methods:BMSCs were cultured in vitro and then labeled with SPIO. Totally 24 male Sprague Dawley (SD) rats weighing 200-250 g were randomly divided into 4 groups: Groups A-D (n=6 for each group). Moderate TBI models of all the rats were developed in the left hemisphere following Feeney's method. Group A was the experimental group and stereotaxic transplantation of BMSCs labeled with SPIO into the region nearby the contusion was conducted in this group 24 hours after TBI modeling. The other three groups were control groups with transplantation of SPIO, unlabeled BMSCs and injection of nutrient solution respectively conducted in Groups B, C and D at the same time. Monitoring of these SPIO-labeled BMSCs by SWI was performed one day,one week and three weeks after implantation.Results: Numerous BMSCs were successfully labeled with SPIO. They were positive for Prussian blue staining and intracytoplasm positive blue stained particles were found under a microscope (×200). Scattered little iron particles were observed in the vesicles by electron microscopy (×5000). MRI of the transplantation sites of the left hemisphere demonstrated a low signal intensity on magnitude images,phase images and SWI images for all the test rats in Group A, and the lesion in the left parietal cortex demonstrated a semicircular low intensity on SWI images, which clearly showed the distribution and migration of BMSCs in the first and third weeks. For Group B, a low signal intensity by MRI was only observed on the first day but undetected during the following examination. No signals were observed in Groups C and D at any time points.Conclusion:SWI sequence in vivo can consecutively and noninvasively trace and demonstrate the

  16. High risk factors of brain metastases in 295 patients with advanced breast cancer

    Institute of Scientific and Technical Information of China (English)

    YAN Min; L(U) Hui-min; LIU Zhen-zhen; LIU Hui; ZHANG Meng-wei; SUN Xi-bin; CUI Shu-de

    2013-01-01

    Background The incidence of brain metastases in patients with breast cancer is approximately 10%-16%,and survival after diagnosis of brain metastases is usually short.This study was designed to evaluate the risk factors associated with brain metastases in advanced breast cancer patients,with a view to help predict patient groups with high risk of brain metastases.Methods In total,295 patients with advanced breast cancer were evaluated.All patients were pathologically confirmed and metastatic lesions were confirmed pathologically or by imaging.All patients were examined at least once every 6 months with head CT or MRI.Patients showing symptoms underwent immediate inspection,and brain metastatic lesions were confirmed by head CT and/or MRI.Results At a median follow-up of 12 months from the occurrence of metastases,brain metastases had occurred in 49 patients (16.6%).In our univariate analysis,variables significantly related to increased risk of brain metastases were hormone receptor-negative tumors,epidermal growth factor receptor 2 (HER2)-positive tumors,and multiple distant metastases.Patients with dominant tumor sites in soft tissue,or defined as Luminal A subtype,tended to have a lower risk of brain metastases than patients with visceral metastases,Luminal B subtype,triple-negative subtype or HER2-enriched subtype tumors.Conclusions Our results strongly suggest that factors such as Luminal B,triple-negative,and HER2-enriched subtypes are high risk factors for brain metastases.These data,therefore,provide pivotal clinical evidence towards a comprehensive understanding of the risk factors of brain metastases in advanced breast cancer patients.

  17. Electronic Configuration of Five-Coordinate High-Spin Pyrazole-Ligated Iron(II) Porphyrinates

    Science.gov (United States)

    Hu, Chuanjiang; Noll, Bruce C.; Schulz, Charles E.; Scheidt, W. Robert

    2010-01-01

    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH3PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphinato core, large equatorial Fe–Np bond distances and a significant out-of-plane displacement of the iron(II) atom. The Fe–N(pyrazole) and Fe–Np bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species. PMID:21047081

  18. Electronic configuration of five-coordinate high-spin pyrazole-ligated iron(II) porphyrinates.

    Science.gov (United States)

    Hu, Chuanjiang; Noll, Bruce C; Schulz, Charles E; Scheidt, W Robert

    2010-12-06

    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH(3)PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphyrinato core, large equatorial Fe-N(p) bond distances, and a significant out-of-plane displacement of the iron(II) atom. The Fe-N(pyrazole) and Fe-N(p) bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and the Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species.

  19. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation

    Science.gov (United States)

    Xing, Lijuan; ten Brink, Gert H.; Chen, Bin; Schmidt, Franz P.; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J.; Palasantzas, George

    2016-05-01

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  20. Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation.

    Science.gov (United States)

    Xing, Lijuan; Ten Brink, Gert H; Chen, Bin; Schmidt, Franz P; Haberfehlner, Georg; Hofer, Ferdinand; Kooi, Bart J; Palasantzas, George

    2016-05-27

    Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment. Moreover, extensive analysis showed that NPs with a size between 10-20 nm possess a truncated cubic morphology, which is confined by the 6 {100} planes that are truncated by the 12 {110} planes at different degrees. For NPs larger than 20 nm, the rhombic dodecahedron defined by the 12 {110} planes is the predominant crystal shape, while truncated rhombic dodecahedrons, as well as non-truncated and truncated cubic NPs, were also observed. The NPs without truncation showed a characteristic inward relaxation indicating that besides thermodynamics kinetics also plays a crucial role during particle growth.

  1. Economically attractive route for the preparation of high quality magnetic nanoparticles by the thermal decomposition of iron(III) acetylacetonate

    Science.gov (United States)

    Effenberger, Fernando B.; Couto, Ricardo A.; Kiyohara, Pedro K.; Machado, Giovanna; Masunaga, Sueli H.; Jardim, Renato F.; Rossi, Liane M.

    2017-03-01

    The thermal decomposition (TD) methods are among the most successful in obtaining magnetic nanoparticles with a high degree of control of size and narrow particle size distribution. Here we investigated the TD of iron(III) acetylacetonate in the presence of oleic acid, oleylamine, and a series of alcohols in order to disclose their role and also investigate economically attractive alternatives for the synthesis of iron oxide nanoparticles without compromising their size and shape control. We have found that some affordable and reasonably less priced alcohols, such as 1,2-octanediol and cyclohexanol, may replace the commonly used and expensive 1,2-hexadecanediol, providing an economically attractive route for the synthesis of high quality magnetic nanoparticles. The relative cost for the preparation of Fe3O4 NPs is reduced to only 21% and 9% of the original cost when using 1,2-octanediol and cyclohexanol, respectively.

  2. Oxygenic Photosynthesis As A Protection Mechanism For Cyanobacteria Against Iron-Encrustation In Environments With High Fe2+ Concentrations

    Directory of Open Access Journals (Sweden)

    Danny eIonescu

    2014-09-01

    Full Text Available If O2 is available at circumneutral pH, Fe2+ is rapidly oxidized to Fe3+, which precipitates as FeO(OH. Neutrophilic iron oxidizing bacteria have evolved mechanisms to prevent self-encrustation in iron. Hitherto, no mechanism has been proposed for cyanobacteria from Fe2+ rich environments; these produce O2 but are seldom found encrusted in iron. We used two sets of illuminated reactors connected to two groundwater aquifers with different Fe2+ concentrations (0.9 µM vs. 26 µM in the Äspö Hard Rock Laboratory, Sweden. Cyanobacterial biofilms developed in all reactors and were phylogenetically different between the reactors. Unexpectedly, cyanobacteria growing in the Fe2+-poor reactors were encrusted in iron, whereas those in the Fe2+-rich reactors were not. In-situ microsensor measurements showed that O2 concentrations and pH near the surface of the cyanobacterial biofilms from the Fe2+-rich reactors were much higher than in the overlying water. This was not the case for the biofilms growing at low Fe2+ concentrations. Measurements with enrichement cultures showed that cyanobacteria from the Fe2+-rich environment increased their photosynthesis with increasing Fe2+ concentrations, whereas those from the low Fe2+ environment were inhibited at Fe2+ > 5 µM. Modeling based on in-situ O2 and pH profiles showed that cyanobacteria from the Fe2+-rich reactor were not exposed to significant Fe2+ concentrations. We propose that, due to limited mass transfer, high photosynthetic activity in Fe2+-rich environments forms a protective zone where Fe2+ precipitates abiotically at a non-lethal distance from the cyanobacteria. This mechanism sheds new light on the possible role of cyanobacteria in precipitation of banded iron formations.

  3. Enhanced trapped field performance of bulk high-temperature superconductors using split coil, pulsed field magnetization with an iron yoke

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Mochizuki, H.; Takahashi, K.; Shi, Y.-H.; Namburi, D. K.; Zou, J.; Zhou, D.; Dennis, A. R.; Cardwell, D. A.

    2016-07-01

    Investigating and predicting the magnetization of bulk superconducting materials and developing practical magnetizing techniques is crucial to using them as trapped field magnets in engineering applications. The pulsed field magnetization (PFM) technique is considered to be a compact, mobile and relative inexpensive way to magnetize bulk samples, requiring shorter magnetization times (on the order of milliseconds) and a smaller and less complicated magnetization fixture; however, the trapped field produced by PFM is generally much smaller than that of slower zero field cooling or field cooling techniques, particularly at lower operating temperatures. In this paper, the PFM of two, standard Ag-containing Gd-Ba-Cu-O samples is carried out using two types of magnetizing coils: (1) a solenoid coil, and (2) a split coil, both of which make use of an iron yoke to enhance the trapped magnetic field. It is shown that a significantly higher trapped field can be achieved using a split coil with an iron yoke, and in order to explain these how this arrangement works in detail, numerical simulations using a 2D axisymmetric finite element method based on the H -formulation are carried to qualitatively reproduce and analyze the magnetization process from both electromagnetic and thermal points of view. It is observed that after the pulse peak significantly less flux exits the bulk when the iron core is present, resulting in a higher peak trapped field, as well as more overall trapped flux, after the magnetization process is complete. The results have important implications for practical applications of bulk superconductors as such a split coil arrangement with an iron yoke could be incorporated into the design of a portable, high magnetic field source/magnet to enhance the available magnetic field or in an axial gap-type bulk superconducting electric machine, where iron can be incorporated into the stator windings to (1) improve the trapped field from the magnetization process

  4. Summary of high field diffusion MRI and microscopy data demonstrate microstructural aberration in chronic mild stress rat brain

    DEFF Research Database (Denmark)

    Khan, Ahmad Raza; Chuhutin, Andrey; Wiborg, Ove

    2016-01-01

    Abstract This data article describes a large, high resolution diffusion MRI data set from fixed rat brain acquired at high field strength. The rat brain samples consist of21adult rat brain hemispheres from animals exposed to chronic mild stress (anhedonic and resilient) and controls. Histology from...

  5. Highly enantioselective transfer hydrogenation of ketones with chiral (NH)2 P2 macrocyclic iron(II) complexes.

    Science.gov (United States)

    Bigler, Raphael; Huber, Raffael; Mezzetti, Antonio

    2015-04-20

    Bis(isonitrile) iron(II) complexes bearing a C2 -symmetric diamino (NH)2 P2 macrocyclic ligand efficiently catalyze the hydrogenation of polar bonds of a broad scope of substrates (ketones, enones, and imines) in high yield (up to 99.5 %), excellent enantioselectivity (up to 99 % ee), and with low catalyst loading (generally 0.1 mol %). The catalyst can be easily tuned by modifying the substituents of the isonitrile ligand.

  6. Iron concentration in breast milk normalised within one week of a single high-dose infusion of iron isomaltoside in randomised controlled trial

    DEFF Research Database (Denmark)

    Holm, Charlotte; Thomsen, Lars Lykke; Nørgaard, Astrid

    2017-01-01

    at a mean daily dose of 70.5mg. We included 65 women with sufficient breast milk three days after inclusion - 30 from the intravenous iron group and 35 from the oral iron group - and collected breast milk and maternal blood samples three days and one week after allocation. RESULTS: The mean (± standard...

  7. Diagnosis and treatment of iron deficiency in patients with heart failure: expert position paper from French cardiologists.

    Science.gov (United States)

    Cohen-Solal, Alain; Leclercq, Christophe; Mebazaa, Alexandre; De Groote, Pascal; Damy, Thibaud; Isnard, Richard; Galinier, Michel

    2014-10-01

    The prevalence of iron deficiency is high -even in the absence of anaemia- in patients with chronic heart failure (HF). Although iron deficiency is easily diagnosed with two biomarkers (serum ferritin and transferrin saturation), it is underdiagnosed in patients with HF. Iron is not only necessary for red blood cells, but also for cells in tissues with high-energy demands (heart, muscle, brain). Even before the onset of anaemia, HF patients with iron deficiency have decreased physical and cognitive performances and a poorer quality of life. Moreover, iron deficiency is a risk factor, independent of anaemia, of unfavourable outcome (death or heart transplantation) in patients with chronic HF. Several randomized controlled studies have shown improvement in exercise capacity, New York Heart Association functional class and quality of life after correction of iron deficiency. The results of these clinical trials, which are supported by European guidelines, suggest considering iron deficiency in HF as a possible therapeutic target.

  8. The green alga Zygogonium ericetorum (Zygnematophyceae, Charophyta) shows high iron and aluminium tolerance: protection mechanisms and photosynthetic performance.

    Science.gov (United States)

    Herburger, Klaus; Remias, Daniel; Holzinger, Andreas

    2016-08-01

    Streptophyte green algae, ancestors of Embryophytes, occur frequently in terrestrial habitats being exposed to high light intensities, water scarcity and potentially toxic metal cations under acidic conditions. The filamentous Zygogonium ericetorum synthesizes a purple vacuolar ferrous pigment, which is lost after aplanospore formation. However, it is unknown whether this cellular reorganization also removes excessive iron from the protoplast and how Z. ericetorum copes with high concentrations of aluminium. Here we show that aplanospore formation shifts iron into the extracellular space of the algal filament. Upon germination of aplanospores, aluminium is bound in the parental cell wall. Both processes reduce iron and aluminium in unpigmented filaments. Comparison of the photosynthetic oxygen production in response to light and temperature gradients in two different Z. ericetorum strains from an Austrian alpine and a Scottish highland habitat revealed lower values in the latter strain. In contrast, the Scottish strain showed a higher optimum quantum yield of PSII during desiccation stress followed by rehydration. Furthermore, pigmented filaments of both strains exhibited a higher light and temperature dependent oxygen production when compared to the unpigmented phenotype. Our results demonstrate a high metal tolerance of Z. ericetorum, which is crucial for surviving in acidic terrestrial habitats. © FEMS 2016.

  9. Effect of molybdenum, vanadium, boron on mechanical properties of high chromium white cast iron in as-cast condition

    Science.gov (United States)

    Nurjaman, F.; Sumardi, S.; Shofi, A.; Aryati, M.; Suharno, B.

    2016-02-01

    In this experiment, the effect of the addition carbide forming elements on high chromium white cast iron, such as molybdenum, vanadium and boron on its mechanical properties and microstructure was investigated. The high chromium white cast iron was produced by casting process and formed in 50 mm size of grinding balls with several compositions. Characterization of these grinding balls was conducted by using some testing methods, such as: chemical and microstructure analysis, hardness, and impact test. From the results, the addition of molybdenum, vanadium, and boron on high chromium white cast iron provided a significant improvement on its hardness, but reduced its toughness. Molybdenum induced fully austenitic matrix and Mo2C formation among eutectic M7C3 carbide. Vanadium was dissolved in the matrix and carbide. While boron was played a role to form fine eutectic carbide. Grinding balls with 1.89 C-13.1 Cr-1.32 Mo-1.36 V-0.00051 B in as-cast condition had the highest hardness, which was caused by finer structure of eutectic carbide, needle like structure (upper bainite) matrix, and martensite on its carbide boundary.

  10. An Innovative Approach to Separate Iron Oxide Concentrate from High-sulfur and Low-grade Pyrite Cinders

    Institute of Scientific and Technical Information of China (English)

    Yong LI; Fu-chun ZHOU; Zhao-xin ZHOU; Zhi-han TIAN; Chao YANG; Xi-ke TIAN

    2016-01-01

    High-sulfur and low-grade pyrite cinders are the waste products of sulfuric acid manufacturing plants. Many valuable components,such as iron oxide,are contained in pyrite cinders and difficult to be separated and puri-fied j ust via the high temperature roasting process.Considering this,an innovative method including water-washing, aqua regia leaching,hydrothermal alkali activation and acid-washing was developed.And the effects of different pa-rameters on recovery efficiency of iron oxide were systematically investigated.The optimum parameters were pro-posed as follows:water rinse-leaching at room temperature for 5-20 min,and melting at 160 ℃ for 2.0 h with NaOH (concentration of 30 mass%),followed by leaching with aqua regia solution (3.0 vol.%)for 1.0 h.After the treatment,the content of iron oxides increased from 54.3 to 96.0 mass% with the recovery rate exceeding 85%. Meanwhile,calcium sulphate was recovered as the high value-added products by alkali extraction liquid.Further-more,the phase transformation and microstructure of the samples in the process were studied by physicochemical methods to reveal the separation mechanisms of different components in the pyrite cinders.

  11. Implication of eolian delivery and accumulation of highly reactive iron to the Atlantic Ocean

    Science.gov (United States)

    Lee, B. K.; Owens, J. D.; Lyons, T. W.

    2014-12-01

    Iron, although abundant in the Earth's crust, is present at low concentrations in sea water and is a limiting nutrient for phytoplankton. Eolian dust (loess) is a major source of this micronutrient, and its deposition has important implications for the global CO2 budget. In this study, we explore distributions of potentially bioreactive Fe, the soluble fraction required by phytoplankton for photosynthesis and nitrogen assimilation, in deep-sea sediments in the North and South Atlantic Oceans. We used a state-of-the-art Fe speciation technique to characterize Fe inputs from different source regions, specifically North Africa and Pata