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Sample records for submicroscopic iron particles

  1. Submicroscopic Nature Needs Megascience

    Science.gov (United States)

    Lederman, Leon

    2005-04-01

    The history of ``submicroscopic nature,'' that is, the history of particle physics, begins in the early 1950's and builds on the construction of a post WWII series of particle accelerators developed to study nuclear physics had been applied to the collisions, in the earth's atmosphere, of cosmic rays. These were high energy particles generated in cosmological events and colliding with oxygen and nitrogen in our atmosphere to create new particles. These studies discovered muons, pions, kaons and lambdas---the beginnings of a vast ``zoo.'' Clearly, studies of the inhabitants of the zoo required energetic collisions, the higher the energy of the accelerator, the more extensive was the range of masses that could be produced and studied. Our paper will review the developments over the past 50 years. As accelerators grew, so did the particle detectors and the sizes of the experimental groups. This will bring us to Fermilab in 2005. Finally, we will describe the ˜900 physicist groups that are cheerfully collaborating, building particle detectors designed to peer deeply into the structure of matter, based upon the ``Large Hadron Collider'' (LHC), an accelerator of unprecedented size, cost, and complexity. The story then takes us from the 100 MeV (10^8 eV) ``atom smashers'' of 1950, to the ˜10 TeV (10^13 eV) behemoth now under construction in Europe. Thus, we move from dozens of machines often on University campuses around the world, to one single megascience device shared by physicists around the world. The motivation for this evolution is physics, as we shall attempt to explain.

  2. Air pollution particles and iron homeostasis

    Science.gov (United States)

    Background: The mechanism underlying biological effects of particles deposited in the lung has not been defined. Major Conclusions: A disruption in iron homeostasis follows exposure of cells to all particulate matter including air pollution particles. Following endocytosis, fun...

  3. Air pollution particles and iron homeostasis | Science ...

    Science.gov (United States)

    Background: The mechanism underlying biological effects of particles deposited in the lung has not been defined. Major Conclusions: A disruption in iron homeostasis follows exposure of cells to all particulate matter including air pollution particles. Following endocytosis, functional groups at the surface of retained particle complex iron available in the cell. In response to a reduction in concentrations of requisite iron, a functional deficiency can result intracellularly. Superoxide production by the cell exposed to a particle increases ferrireduction which facilitates import of iron with the objective being the reversal of the metal deficiency. Failure to resolve the functional iron deficiency following cell exposure to particles activates kinases and transcription factors resulting in a release of inflammatory mediators and inflammation. Tissue injury is the end product of this disruption in iron homeostasis initiated by the particle exposure. Elevation of available iron to the cell precludes deficiency of the metal and either diminishes or eliminates biological effects.General Significance: Recognition of the pathway for biological effects after particle exposure to involve a functional deficiency of iron suggests novel therapies such as metal supplementation (e.g. inhaled and oral). In addition, the demonstration of a shared mechanism of biological effects allows understanding the common clinical, physiological, and pathological presentation fol

  4. Carbon-Supported Iron Oxide Particles

    DEFF Research Database (Denmark)

    Meaz, T.; Mørup, Steen; Koch, C. Bender

    1996-01-01

    A carbon black ws impregnated with 6 wt% iron using an aqueous solution of iron nitrate. The impregnated carbon was initially dried at 125 C. The effect of heating of the iron oxide phase was investigated at temperatures between 200 and 600 C using Mossbauer spectroscopy. All heat treatments were...... done in an oxygen-containing atmosphere. Ferrihydrite is formed and is stable at and below a temperature of 300 C. At 600 C small particles of maghemite is the dominant iron oxide. A transformation reaction is suggested....

  5. Colloidal iron(III) pyrophosphate particles

    NARCIS (Netherlands)

    Rossi, L.; Velikov, K. P.; Philipse, A.P.

    2014-01-01

    Ferric pyrophosphate is a widely used material in the area of mineral fortification but its synthesis and properties in colloidal form are largely unknown. In this article, we report on the synthesis and characterisation of colloidal iron(III) pyrophosphate particles with potential for application

  6. Particle interactions of polyvinylpyrrolidone-coated iron oxide particles as magnetic drug delivery agents

    Science.gov (United States)

    İşçi, Sevim; İşçi, Yavuz; Bekaroğlu, Maide Gökçe

    2017-08-01

    Iron oxide particles have been recently researched for the potential applications of targeted drug delivery due to their magnetic properties. The surfaces of the iron oxide particles must be modified to reduce the toxicity and to load the drug to the particles. Biopolymers are good surface modifiers of colloidal particles such as iron oxide particles. The degree of surface coverage of the colloidal iron oxide particles affects the stability, toxicity, magnetic properties and drug loading efficiency. In this study, the interactions of iron oxide (Fe3O4) particles and PVP were determined according to the colloidal properties. The proper concentration of PVP for the whole coverage of the iron oxide particles was found for the possible magnetic drug delivery applications by controlling the colloidal properties of the dispersions. The magnetic properties and toxicity of the fully covered bioiron oxide was also determined for possible applications.

  7. Ultrasmall iron particles prepared by use of sodium amalgam

    DEFF Research Database (Denmark)

    Linderoth, Søren; Mørup, Steen

    1990-01-01

    Ultrasmall magnetic particles containing iron have been prepared by reduction of iron ions by the use of sodium in mercury. Mössbauer studies at 12 K show that the magnetic hyperfine field is significantly larger than in bulk alpha-Fe, suggesting that an iron mercury alloy rather than alpha-Fe ha...... been formed. The particles exhibit superparamagnetic relaxation above 120 K. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  8. Iron Mobilization from Particles as a Function of pH and Particle Source

    National Research Council Canada - National Science Library

    Rohrbough, James

    2000-01-01

    .... The work presented here shows the role pH can play in iron mobilization from particles. At low pH, bioavailability of iron can be greatly increased, and can be significantly decreased at higher pH...

  9. Imported submicroscopic malaria in Madrid

    Directory of Open Access Journals (Sweden)

    Ramírez-Olivencia Germán

    2012-09-01

    Full Text Available Abstract Background Submicroscopic malaria (SMM can be defined as low-density infections of Plasmodium that are unlikely to be detected by conventional microscopy. Such submicroscopic infections only occasionally cause acute disease, but they are capable of infecting mosquitoes and contributing to transmission. This entity is frequent in endemic countries; however, little is known about imported SMM. The goals of this study were two-fold: a to know the frequency of imported SMM, and b to describe epidemiological, laboratorial and clinical features of imported SMM. Methods A retrospective study based on review of medical records was performed. The study population consisted of patients older than 15 years attended at the Tropical Medicine Unit of Hospital Carlos III, between January 1, 2002 and December 31, 2007. Routinely detection techniques for Plasmodium included Field staining and microscopic examination through thick and thin blood smear. A semi-nested multiplex malaria PCR was used to diagnose or to confirm cases with low parasitaemia. Results SMM was diagnosed in 104 cases, representing 35.5% of all malaria cases. Mean age (IC95% was 40.38 years (37.41-43.34, and sex distribution was similar. Most cases were in immigrants, but some cases were found in travellers. Equatorial Guinea was the main country where infection was acquired (81.7%. Symptoms were present only in 28.8% of all SMM cases, mainly asthenia (73.3% of symptomatic patients, fever (60% and arthromialgias (53.3%. The associated laboratory abnormalities were anaemia (27.9%, leukopaenia (15.4% and thrombopaenia (15.4%. Co-morbidity was described in 75 cases (72.1%. Conclusions Results from this study suggest that imported SMM should be considered in some patients attended at Tropical Medicine Units. Although it is usually asymptomatic, it may be responsible of fever, or laboratory abnormalities in patients coming from endemic areas. The possibility of transmission in SMM has

  10. EM-wave absorption properties of hollow spiral iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenqiang, E-mail: zwqcau@gmail.com [College of Engineering, China Agricultural University, Beijing 100083 (China); Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China)

    2015-12-15

    Hollow iron spiral particles were fabricated successfully by thermal decomposition method, and they were heat-treated at different temperatures in N{sub 2} atmosphere. The electromagnetic wave absorption properties of hollow iron spiral particles were investigated ranging between 1 GHz and 18 GHz. The results indicated that the phase structures of the particles changed from amorphous to nanocrystal with the treating temperature rising, also causing the significant change in electromagnetic parameters and the reflection loss. The reflection loss could reach −33 dB at 16.2 GHz, indicating that the hollow iron spiral particles had the potential to be used in prepare the a high property EM-wave absorber. - Highlights: • Hollow iron spiral particles were fabricated by thermal decomposition method. • The particles changed from amorphous to nanocrystals with heat-treatment. • Particles’ EM-parameters have a great change after high temperature heat-treatment. • RL results show the particles have potential to be high property EM-wave absorber.

  11. Investigating Macroscopic, Submicroscopic, and Symbolic Connections in a College-Level General Chemistry Laboratory

    Science.gov (United States)

    Thadison, Felicia Culver

    2011-01-01

    Explanations of chemical phenomena rely on understanding the behavior of submicroscopic particles. Because this level is "invisible," it is described using symbols such as models, diagrams and equations. For this reason, students often view chemistry as a "difficult" subject. The laboratory offers a unique opportunity for the students to…

  12. Iron oxide and iron carbide particles produced by the polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Y., E-mail: yyasu@rs.kagu.tus.ac.jp; Shimizu, R. [Tokyo University of Science, Department of Chemistry (Japan); Kobayashi, Y. [The University of Electro-Communications, Graduate School of Informatics and Engineering (Japan)

    2016-12-15

    Iron oxide (γ-Fe{sub 2}O{sub 3}) and iron carbide (Fe{sub 3}C) particles were produced by the polyol method. Ferrocene, which was employed as an iron source, was decomposed in a mixture of 1,2-hexadecandiol, oleylamine, and 1-octadecene. Particles were characterized using Mössbauer spectroscopy, X-ray diffraction, and transmission electron microscopy. It was found that oleylamine acted as a capping reagent, leading to uniform-sized (12-16 nm) particles consisting of γ-Fe {sub 2}O{sub 3}. On the other hand, 1-octadecene acted as a non-coordinating solvent and a carbon source, which led to particles consisting of Fe{sub 3}C and α-Fe with various sizes.

  13. Effect of particle size on iron nanoparticle oxidation state

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, Jeffrey J.; Lysaght, Andrew C. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, 97 North Eagleville Road, Storrs, CT 06269-3139 (United States); Goberman, Daniel G. [Institute of Materials Science, University of Connecticut, Storrs, CT 06269-3136 (United States); Chiu, Wilson K.S., E-mail: wchiu@engr.uconn.edu [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, 97 North Eagleville Road, Storrs, CT 06269-3139 (United States)

    2012-01-01

    Selecting catalyst particles is a very important part of carbon nanotube growth, although the properties of these nanoscale particles are unclear. In this article iron nanoparticles are analyzed through the use of atomic force microscopy and x-ray photoelectron spectroscopy in order to understand how the size affects the chemical composition of nanoparticles and thus their physical structure. Initially, atomic force microscopy was used to confirm the presence of iron particles, and to determine the average size of the particles. Next an analytical model was developed to estimate particle size as a function of deposition time using inputs from atomic force microscopy measurement. X-ray photoelectron spectroscopy analysis was then performed with a focus on the spectra relating to the 2p Fe electrons to study the chemical state of the particles as a function of time. It was shown that as the size of nanoparticles decreased, the oxidation state of the particles changed due to a high proportion of atoms on the surface.

  14. Investigating macroscopic, submicroscopic, and symbolic connections in a college-level general chemistry laboratory

    Science.gov (United States)

    Thadison, Felicia Culver

    Explanations of chemical phenomena rely on understanding the behavior of submicroscopic particles. Because this level is "invisible," it is described using symbols such as models, diagrams and equations. For this reason, students often view chemistry as a "difficult" subject. The laboratory offers a unique opportunity for the students to experience chemistry macroscopically as well as symbolically. The purpose of this investigation was to determine how chemistry lab students explained chemical phenomenon on the macroscopic, submicroscopic, and representational/symbolic level. The participants were undergraduate students enrolled in an introductory level general chemistry lab course. Students' background information (gender, the number of previous chemistry courses), scores on final exams, and final average for the course were collected. Johnstone's triangle of representation guided the design and implementation of this study. A semi-structured interview was also conducted to bring out student explanations. The questionnaires required students to draw a molecule of water, complete acid base reaction equations, represent, submicroscopically, the four stages of an acid-base titration, and provide definitions of various terms. Students were able represent the submicroscopic level of water. Students were not able to represent the submicroscopic level of the reaction between an acid and a base. Students were able to represent the macroscopic level of an acid base reaction. Students were able to symbolically represent the reaction of an acid and a base. These findings indicate that students can use all three levels of chemical representation. However, students showed an inability to connect the levels in relation to acid-base chemistry. There was no relationship between a student's ability to use the levels and his or her final score in the course.

  15. Electrochemical Aspects of the Synthesis of Iron Particles

    Directory of Open Access Journals (Sweden)

    Tatjana MALIAR

    2012-09-01

    Full Text Available The preparation of Fe-particles by reduction of FeSO4 with either sodium borohydride or lithium triethylborohydride in water, and reverse micelles in rapeseed and mineral oil phases is described in electrochemical terms. The influence of surfactants on the electrochemical parameters and resulting size of iron particles was studied as well. The resulting size of Fe-particles synthesized in water (with and without surfactants correlates with the determined values of open circuit potential (OCP: the more negative OCP, the obtained Fe-particles are bigger, because values of OCP correspond to different range of polarization determined for the reduction of Fe2+. The sizes of Fe-particles synthesized in water or oil phases without surfactants using LiBEt3H are less than using NaBH4 because of electrochemical factors. By varying oils and surfactants it is possible to obtain opposite results as in water phase: smaller Fe-particles obtained using NaBH4 than using LiBEt3H. It is explained by the simultaneous influence of electrochemical and steric stabilization factors, and the last one becomes dominating in some cases.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2429

  16. The Role and Potential Dangers of Visualisation when Learning about Sub-Microscopic Explanations in Chemistry Education

    Directory of Open Access Journals (Sweden)

    Ingo Eilks

    2012-01-01

    Full Text Available The core of theory-driven chemistry education consists of the constantshift between the different representational domains of chemical thinking: the macroscopic, the sub-microscopic, and the symbolic domains. Because the sub-microscopic domain can neither be seen nor directly visualised, it requires specific forms of visualisation, i.e. pictures and animations illustrating the model-based level of discrete particles, atoms, or molecular structures. This paper considers the central role visualisations play when learning about the model-based, sub-microscopic level, but it also reflects the dangers inherent in employing isufficiently examined, poorly considered, or even misleading visualisations. This is outlined using different examples taken from both textbooks for lower secondary chemistry education (for students aged 10 to 15 and from the internet. Implications for structuring and using sub-micro visualisations in chemistry education are also given.

  17. Liquid Plasma Synthesis of Carbon Coated Iron Oxide Particles

    Science.gov (United States)

    Uygun, Aysegul; Hershkowitz, Noah; Eren, Esin; Uygun, Emre; Celik Cogal, Gamze; Yurdabak Karaca, Gozde; Manolache, Sorin; Sundaram, Gunasekaran; Sadak, Omer; Oksuz, Lutfi

    2017-10-01

    Recently, magnetic metal or metal oxide nanoparticles encapsulated in carbon are important in biomedical applications. The relevant reason to study toxicity of the magnetic nanoparticles coated by carbon is that they have great potential to contribute to cancer treatment. In this work, the synthesis of iron oxide nano-particles coated by graphitic carbon shells using pulsed plasma in liquid method. Short duration of RF plasma discharge, low electrical energy and fast quenching of the surrounding media can let to synthesize various kinds of pure nanoparticles. Corresponding author: ayseguluygun@sdu.edu.tr, lutfioksuz@sdu.edu.tr.

  18. Structural, microstructural and hyperfine properties of nanocrystalline iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Guittoum, A., E-mail: guittoum@yahoo.f [Centre de Recherche Nucleaire d' Alger, 2 Bd Frantz Fanon, BP 399 Alger-Gare, Alger (Algeria); Layadi, A. [Departement de Physique, Faculte des Sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Tafat, H. [Faculte de Mecanique et Genie des Procedes, USTHB de Bab Ezzouar (Algeria); Souami, N. [Centre de Recherche Nucleaire d' Alger, 2 Bd Frantz Fanon, BP 399 Alger-Gare, Alger (Algeria)

    2010-03-15

    Nanocrystalline Fe particles were successfully prepared by the mechanical milling process using a high-energy planetary ball mill. The physical properties of the samples were investigated as a function of the milling time, t (in the 0-54 h range) by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Moessbauer spectroscopy. After 54 h of milling, the lattice parameter increases from 0.28620 (3) nm for the starting Fe powder to 0.28667 (3) nm, the grain size decreases from 110 to 13 nm, while the strain increases from 0.09% to 0.7%. The powder particle morphology was observed by SEM at different stages of milling. For t less than 24 h, the Moessbauer spectra are characterized by one sextet corresponding to the crystalline bcc Fe phase, while for t greater than 24 h, the iron particles exhibit a two-component Moessbauer spectrum due to the presence of two phases: the crystallites bcc Fe phase and the grain-boundary region. The appearance and the increase in intensity of the second sextet with t may indicate that the interfacial region effect increases with milling time due to the grain size reduction and a probable disordered state of the grain boundaries.

  19. Wood smoke particle sequesters cell iron to impact a biological effect.

    Science.gov (United States)

    The biological effect of an inorganic particle (i.e., silica) can be associated with a disruption in cell iron homeostasis. Organic compounds included in particles originating from combustion processes can also complex sources of host cell iron to disrupt metal homeostasis. We te...

  20. Enhancement of iron content in spinach plants stimulated by magnetic nano particles

    Energy Technology Data Exchange (ETDEWEB)

    Yulianto, Agus; Astuti, Budi; Amalia, Saptaria Rosa [Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Semarang (Indonesia)

    2016-04-19

    In our previous study, the iron content in spinach plants could be detected by magnetic susceptibility values. In the present work, magnetic nano particles were found from the iron sand. The magnetic nano particles are synthesis by using co-precipitation process and sol-gel technique. The stimulation of magnetic nano particles in the plant has been done by the provision of magnetic nano particles in growing media. After certain time, plant samples was characterized using susceptibility-meter MS2B and atomic absorption spectroscopy to measure the magnetic susceptibility and the amount of iron content that absorbed of the plant, respectively. The iron content in the spinach plants was increased when the magnetic nano particles was injected in the growing media.

  1. Enhancement of iron content in spinach plants stimulated by magnetic nano particles

    Science.gov (United States)

    Yulianto, Agus; Astuti, Budi; Amalia, Saptaria Rosa

    2016-04-01

    In our previous study, the iron content in spinach plants could be detected by magnetic susceptibility values. In the present work, magnetic nano particles were found from the iron sand. The magnetic nano particles are synthesis by using co-precipitation process and sol-gel technique. The stimulation of magnetic nano particles in the plant has been done by the provision of magnetic nano particles in growing media. After certain time, plant samples was characterized using susceptibility-meter MS2B and atomic absorption spectroscopy to measure the magnetic susceptibility and the amount of iron content that absorbed of the plant, respectively. The iron content in the spinach plants was increased when the magnetic nano particles was injected in the growing media.

  2. 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.

  3. Elimination of Iron Based Particles in Al-Si Alloy

    Directory of Open Access Journals (Sweden)

    Bolibruchová D.

    2015-03-01

    Full Text Available This paper deals with influence on segregation of iron based phases on the secondary alloy AlSi7Mg0.3 microstructure by chrome. Iron is the most common and harmful impurity in aluminum casting alloys and has long been associated with an increase of casting defects. In generally, iron is associated with the formation of Fe-rich phases. It is impossible to remove iron from melt by standard operations, but it is possible to eliminate its negative influence by addition some other elements that affect the segregation of intermetallics in less harmful type. Realization of experiments and results of analysis show new view on solubility of iron based phases during melt preparation with higher iron content and influence of chrome as iron corrector of iron based phases. By experimental work were used three different amounts of AlCr20 master alloy a three different temperature of chill mold. Our experimental work confirmed that chrome can be used as an iron corrector in Al-Si alloy, due to the change of intermetallic phases and shortening their length.

  4. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  5. Electroless plating preparation and electromagnetic properties of Co-coated carbonyl iron particles/polyimide composite

    Science.gov (United States)

    Zhou, Yingying; Zhou, Wancheng; Li, Rong; Qing, Yuchang; Luo, Fa; Zhu, Dongmei

    2016-03-01

    To solve the serious electromagnetic interference problems at elevated temperature, one thin microwave-absorbing sheet employing Co-coated carbonyl iron particles and polyimide was prepared. The Co-coated carbonyl iron particles were successfully prepared using an electroless plating method. The microstructure, composition, phase and static magnetic properties of Co-coated carbonyl iron particles were characterized by combination of scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The electromagnetic parameters of Co-coated carbonyl iron particles/polyimide composite were measured in the frequency range of 2-18 GHz, and the electromagnetic loss mechanism of the material-obtained was discussed. The microwave absorption properties of composites before and after heat treatment at 300 °C for 100 h were characterized in 2-18 GHz frequency range. It was established that composites based on Co-coated carbonyl iron demonstrate thermomagnetic stability, indicating that Co coating reduces the oxidation of carbonyl iron. Thus, Co-coated carbonyl iron particles/polyimide composites are useful in the design of microwave absorbers operating at temperatures up to 300 °C.

  6. Identification of submicroscopic chromosomal aberrations in fetuses with increased

    DEFF Research Database (Denmark)

    Leung, Tak Yeung; Vogel, Ida; Lau, Tze Kin

    2011-01-01

    Objective: Fetal nuchal translucency (NT) is assessed by ultrasound as a screening tool for aneuploidy at 11-13+6 weeks’ gestation. Fetuses with increased NT but apparently normal karyotyping result are still at higher risk of structural abnormality and a range of genetic syndromes, which may...... sonographic anomalies, and 5.3% (2/38) among those without. Conclusions: aCGH allows detection of submicroscopic chromosomal abnormalities of which the prevalence may be increased in fetuses with NT>3.5mm and an apparently normal karyotype....... be related to major and submicroscopic chromosomal abnormalities. The aim of our study is to report the prevalence of submicroscopic chromosomal abnormalities in a cohort of apparently euploid fetuses that presented with increased NT. Methods: DNA was extracted from stored CVS specimens relating to fetuses...

  7. Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

    Digital Repository Service at National Institute of Oceanography (India)

    Martin, P.; Loeff, M.M.R. van der.; Cassar, N.; Vandromme, P.; d'Ovidio, F.; Stemmann, L.; Rengarajan, R.; Soares, M.A.; Gonzalez, H.E.; Ebersbach, F.; Lampitt, R.S.; Sanders, R.; Barnett, B.A.; Smetacek, V.; Naqvi, S.W.A.

    A closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux...

  8. Nano iron particles transport in fractured rocks: laboratory and field scale

    Science.gov (United States)

    Cohen, Meirav; Weisbrod, Noam

    2017-04-01

    Our study deals with the transport potential of nano iron particles (NIPs) in fractured media. Two different systemswere used to investigate transport on two scales: (1 )a laboratory flow system of a naturally discrete fractured chalk core, 0.43 and 0.18 m in length and diamater, respectively; and (2) a field system of hydraulically connected boreholes located 47 m apart which penetrate a fractured chalk aquifer. We started by testing the transport potential of various NIPs under different conditions. Particle stability experiments were conducted using various NIPs and different stabilizersat two ionic strengths. Overall, four different NIPs and three stabilizers were tested. Particles and solution properties (stability, aggregate/particle size, viscosity and density) were tested in batch experiments, and transport experiments (breakthrough curves (BTCs) and recovery) were conduted in the fractured chalk core. We have learned that the key parameters controlling particle transport are the particle/aggregate size and stability, which govern NIP settling rates and ultimately their migration distance. The governing mechanism controlling NIP transport was found to be sedimentation, and to a much lesser extent, processes such as diffusion, straining or interception. On the basis of these experiments, Carbo-Iron® particles ( 800 nm activated carbon particles doped with nano zero valent iron particles) and Carboxymethyl cellulose (CMC) stabilizer were selected for the field test injection. In the field, Carbo-Iron particles were initially injected into the fractured aquifer using an excess of stabilizer in order to ensure maximum recovery. This resulted in high particle recovery and fast arrival time, similar to the ideal tracer (iodide). The high recovery of the stable particle solution emphasized the importance of particle stability for transport in fractures. To test mobility manipulation potential of the particles and simulate more realistic scenarios, a second field

  9. In Vitro Biocompatibility of Nanoscale Zerovalent Iron Particles (NZVI) Synthesized using tea-polyphenols.

    Science.gov (United States)

    A “green” protocol was used for the rapid generation of nanoscale zerovalent iron (NZVI) particles using tea polyphenols. The NZVI particles were subsequently examined for in vitro biocompatibility using the human keratinocyte cell (HaCaT) line as a skin exposure model. The cell...

  10. Corrosion rate estimations of microscale zerovalent iron particles via direct hydrogen production measurements.

    Science.gov (United States)

    Velimirovic, Milica; Carniato, Luca; Simons, Queenie; Schoups, Gerrit; Seuntjens, Piet; Bastiaens, Leen

    2014-04-15

    In this study, the aging behavior of microscale zerovalent iron (mZVI) particles was investigated by quantifying the hydrogen gas generated by anaerobic mZVI corrosion in batch degradation experiments. Granular iron and nanoscale zerovalent iron (nZVI) particles were included in this study as controls. Firstly, experiments in liquid medium (without aquifer material) were performed and revealed that mZVI particles have approximately a 10-30 times lower corrosion rate than nZVI particles. A good correlation was found between surface area normalized corrosion rate (RSA) and reaction rate constants (kSA) of PCE, TCE, cDCE and 1,1,1-TCA. Generally, particles with higher degradation rates also have faster corrosion rates, but exceptions do exists. In a second phase, the hydrogen evolution was also monitored during batch tests in the presence of aquifer material and real groundwater. A 4-9 times higher corrosion rate of mZVI particles was observed under the natural environment in comparison with the aquifer free artificial condition, which can be attributed to the low pH of the aquifer and its buffer capacity. A corrosion model was calibrated on the batch experiments to take into account the inhibitory effects of the corrosion products (dissolved iron, hydrogen and OH(-)) on the iron corrosion rate. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. The role of submicroscopic and symbolic representations in chemical explanations

    Science.gov (United States)

    Treagust, David F.; Chittleborough, Gail; Mamiala, Thapelo L.

    2003-11-01

    Chemistry is commonly portrayed at three different levels of representation - macroscopic, submicroscopic and symbolic - that combine to enrich the explanations of chemical concepts. In this article, we examine the use of submicroscopic and symbolic representations in chemical explanations and ascertain how they provide meaning. Of specific interest is the development of students' levels of understanding, conceived as instrumental (knowing how) and relational (knowing why) understanding, as a result of regular Grade 11 chemistry lessons using analogical, anthropomorphic, relational, problem-based, and model-based explanations. Examples of both teachers' and students' dialogue are used to illustrate how submicroscopic and symbolic representations are manifested in their explanations of observed chemical phenomena. The data in this research indicated that effective learning at a relational level of understanding requires simultaneous use of submicroscopic and symbolic representations in chemical explanations. Representations are used to help the learner learn; however, the research findings showed that students do not always understand the role of the representation that is assumed by the teacher.

  12. Carriage of sub-microscopic sexual and asexual Plasmodium ...

    African Journals Online (AJOL)

    SUMMARY. Background: We investigated the prevalence of sub-microscopic Plasmodium falciparum infections and gameto- cyte carriage in asymptomatic individuals in Navrongo in northern Ghana, an area of seasonal malaria transmission. Design: A cross sectional study of 209 randomly selected participants of all ...

  13. Carriage of sub-microscopic sexual and asexual Plasmodium ...

    African Journals Online (AJOL)

    Carriage of sub-microscopic sexual and asexual Plasmodium falciparum stages in the dry season at Navrongo, Ghana. ... infections and therefore the need for active case detection surveillance to eliminate "asymptomatic reservoir" parasites and consequently break the transmission of the disease in Ghana. Funding: Bill ...

  14. Effect of carbonyl iron particles composition on the physical characteristics of MR grease

    Energy Technology Data Exchange (ETDEWEB)

    Mohamad, Norzilawati, E-mail: mnorzilawati@gmail.com; Mazlan, Saiful Amri, E-mail: amri.kl@utm.my [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Ubaidillah, E-mail: ubaidillah@uns.ac.id [Vehicle System Engineering, Malaysia – Japan International Institute of Technology, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra (Jalan Semarak), Kuala Lumpur, 54000 (Malaysia); Mechanical Engineering Department, Faculty of Engineering, Universitas Sebelas Maret, Jl. Ir. Sutami 36A, Kentingan, Surakarta, 57126, Central Java, Surakarta (Indonesia)

    2016-03-29

    Magnetorheological (MR) grease is an extension of the study of magnetorheological materials. The MR grease can help to reduce the particles sedimentation problem occurred in the MR fluids. Within this study, an effort has been taken to investigate the effect of different weight compositions of carbonyl iron particles on the physical and chemical characteristics of the MR grease under off-state condition (no magnetic field). The MR grease is prepared by mixing carbonyl iron particles having a size range of 1 to 10 µm with commercial NPC Highrex HD-3 grease. Characterizations of MR grease are investigated using Vibrating Sample Magnetometer (VSM), Environmental Scanning Electron Microscopy (ESEM), Differential Scanning Calorimeter (DSC) and rheometer. The dependency of carbonyl iron particles weight towards the magnetic properties of MR grease and other characterizations are investigated.

  15. Nanoscale lignin particles as sources of dissolved iron to the ocean

    Science.gov (United States)

    Krachler, Regina; von der Kammer, Frank; Jirsa, Franz; Süphandag, Altan; Krachler, Rudolf F.; Plessl, Christof; Vogt, Margret; Keppler, Bernhard K.; Hofmann, Thilo

    2012-09-01

    Primary production in large areas of the open ocean is limited by low iron concentrations. Rivers are potential sources of iron to the ocean, however, riverine iron is prone to intense flocculation and sedimentation in the estuarine mixing zone. Here we report the detection of iron-rich nanoparticles in a typical peatland-draining creek which are resistant against salt-induced flocculation i.e., their behavior is in sharp contrast to the well-known behavior of Fe colloids in river waters. Sample fractionation by AsFlFFF (Asymmetric Flow Field Flow Fractionation) revealed that these powerful iron carriers are in the size range of only 0.5-3.0 nm hydrodynamic diameter. They were isolated from the water phase using solid phase extraction/gel permeation chromatography, and analyzed by a CuO oxidation/GC-MS method. Our results suggest that the particles consist mainly of lignin catabolites and that gymnosperm as well as angiosperm tissues are contributors to the seawater-resistant iron-bearing DOM. Lignin phenols, which have no autochthonous source in the ocean, have been nevertheless found in low concentrations throughout the entire Arctic, Atlantic, and Pacific oceans. It is therefore tempting to speculate that peatland-derived iron-bearing lignin particles may have a sufficiently long half-life in ocean waters to sustain iron concentration in extended regions of the ocean.

  16. Effect of particle size on kinetics crystallization of an iron-rich glass

    OpenAIRE

    Romero, Maximina; Kovacova, Milota; Rincón López, Jesús María

    2008-01-01

    The effect of glass particle size on the crystallization kinetics of an iron-rich glass from a nickel leaching waste has been investigated by means of differential thermal analysis (DTA). The results show that the crystallization of a pyroxene phase occurs by bulk nucleation from a constant number of nuclei. The crystallization mode and the dimensionality of crystals are strongly dependent of the glass particle size, being 100µm the critical size. Glass fractions with particle size >100µm sho...

  17. In vitro neurotoxic effects of 1 GeV/n iron particles assessed in retinal explants.

    Science.gov (United States)

    Vazquez, M E; Kirk, E

    2000-01-01

    The heavy ion component of the cosmic radiation remains problematic to the assessment of risk in manned space flight. The biological effectiveness of HZE particles has yet to be established, particularly with regard to nervous tissue. Using heavy ions accelerated at the AGS of Brookhaven National Laboratory, we study the neurotoxic effects of iron particles. We exposed retinal explants, taken from chick embryos, to determine the dose response relationships for neurite outgrowth. Morphometric techniques were used to evaluate the in vitro effects of 1 GeV/a iron particles (LET 148 keV/micrometer). Iron particles produced a dose-dependent reduction of neurite outgrowth with a maximal effect achieved with a dose of 100 cGy. Doses as low as 10-50 cGy were able to induce reductions of the neurite outgrowth as compared to the control group. Neurite generation is a more sensitive parameter than neurite elongation, suggesting different mechanism of radiation damage in our model. These results showed that low doses/fluences of iron particles could impair the retinal ganglion cells' capacity to generate neurites indicating the highly neurotoxic capability of this heavy charged particle.

  18. Magnetization curling in perpendicular iron particle arrays (alumite media)

    NARCIS (Netherlands)

    Huysmans, G.T.A.; Lodder, J.C.; Wakui, J.

    1988-01-01

    Alumite has been investigated by measuring the hysteresis loops for different field directions to determine the influence of the particle interactions in an perpendicular oriented particle medium on the angular dependence of the coercivity and the hsyteresis loss. Alumite is an ideal model material

  19. Reversal behaviour in perpendicular iron particle arrays (alumite media)

    NARCIS (Netherlands)

    Lodder, J.C.; Li, Cheng-Zhang

    1989-01-01

    Alumite was chosen as an ideal material to investigate the influence of particle interaction on the magnetic behaviour of a perpendicular anisotropic particle array. It was found that the measured reduced coercivity versus the reduced diameter curves fits the theoretical curling mode. However, the

  20. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation

    Energy Technology Data Exchange (ETDEWEB)

    Velimirovic, Milica; Schmid, Doris; Wagner, Stephan; Micić, Vesna; Kammer, Frank von der; Hofmann, Thilo, E-mail: thilo.hofmann@univie.ac.at

    2016-09-01

    Submicron-scale milled zerovalent iron (milled ZVI) particles produced by grinding macroscopic raw materials could provide a cost-effective alternative to nanoscale zerovalent iron (nZVI) particles for in situ degradation of chlorinated aliphatic hydrocarbons in groundwater. However, the aggregation and settling of bare milled ZVI particles from suspension presents a significant obstacle to their in situ application for groundwater remediation. In our investigations we reduced the rapid aggregation and settling rate of bare milled ZVI particles from suspension by stabilization with a “green” agar agar polymer. The transport potential of stabilized milled ZVI particle suspensions in a diverse array of natural heterogeneous porous media was evaluated in a series of well-controlled laboratory column experiments. The impact of agar agar on trichloroethene (TCE) removal by milled ZVI particles was assessed in laboratory-scale batch reactors. The use of agar agar significantly enhanced the transport of milled ZVI particles in all of the investigated porous media. Reactivity tests showed that the agar agar-stabilized milled ZVI particles were reactive towards TCE, but that their reactivity was an order of magnitude less than that of bare, non-stabilized milled ZVI particles. Our results suggest that milled ZVI particles could be used as an alternative to nZVI particles as their potential for emplacement into contaminated zone, their reactivity, and expected longevity are beneficial for in situ groundwater remediation. - Highlights: • Rapid aggregation and sedimentation were observed in bare milled ZVI particles. • Agar agar improved the stability of milled ZVI particle suspensions. • Agar agar enhanced the transport of milled ZVI particles in heterogeneous sands. • Agar agar reduced the reactivity of milled ZVI particles towards TCE.

  1. Biofuel-Promoted Polychlorinated Dibenzodioxin/furan Formation in an Iron-Catalyzed Diesel Particle Filter.

    Science.gov (United States)

    Heeb, Norbert V; Rey, Maria Dolores; Zennegg, Markus; Haag, Regula; Wichser, Adrian; Schmid, Peter; Seiler, Cornelia; Honegger, Peter; Zeyer, Kerstin; Mohn, Joachim; Bürki, Samuel; Zimmerli, Yan; Czerwinski, Jan; Mayer, Andreas

    2015-08-04

    Iron-catalyzed diesel particle filters (DPFs) are widely used for particle abatement. Active catalyst particles, so-called fuel-borne catalysts (FBCs), are formed in situ, in the engine, when combusting precursors, which were premixed with the fuel. The obtained iron oxide particles catalyze soot oxidation in filters. Iron-catalyzed DPFs are considered as safe with respect to their potential to form polychlorinated dibenzodioxins/furans (PCDD/Fs). We reported that a bimetallic potassium/iron FBC supported an intense PCDD/F formation in a DPF. Here, we discuss the impact of fatty acid methyl ester (FAME) biofuel on PCDD/F emissions. The iron-catalyzed DPF indeed supported a PCDD/F formation with biofuel but remained inactive with petroleum-derived diesel fuel. PCDD/F emissions (I-TEQ) increased 23-fold when comparing biofuel and diesel data. Emissions of 2,3,7,8-TCDD, the most toxic congener [toxicity equivalence factor (TEF) = 1.0], increased 90-fold, and those of 2,3,7,8-TCDF (TEF = 0.1) increased 170-fold. Congener patterns also changed, indicating a preferential formation of tetra- and penta-chlorodibenzofurans. Thus, an inactive iron-catalyzed DPF becomes active, supporting a PCDD/F formation, when operated with biofuel containing impurities of potassium. Alkali metals are inherent constituents of biofuels. According to the current European Union (EU) legislation, levels of 5 μg/g are accepted. We conclude that risks for a secondary PCDD/F formation in iron-catalyzed DPFs increase when combusting potassium-containing biofuels.

  2. Carburizer particle dissolution in liquid cast iron – computer simulation

    Directory of Open Access Journals (Sweden)

    D. Bartocha

    2010-01-01

    Full Text Available In the paper issue of dissolution of carburizing materials (anthracite, petroleum coke and graphite particle in liquid metal and its computer simulation are presented. Relative movement rate of particle and liquid metal and thermophsical properties of carburizing materials (thermal conductivity coefficient, specific heat, thermal diffusivity, density are taken into consideration in calculations. Calculations have been carried out in aspect of metal bath carburization in metallurgical furnaces.

  3. Impact of protein pre-treatment conditions on the iron encapsulation efficiency of whey protein cold-set gel particles

    NARCIS (Netherlands)

    Martin, A.H.; Jong, G.A.H. de

    2012-01-01

    This paper investigates the possibility for iron fortification of food using protein gel particles in which iron is entrapped using cold-set gelation. The aim is to optimize the iron encapsulation efficiency of whey protein by giving the whey protein different heat treatment prior to gelation with

  4. Wear Behaviour of Iron Matrix Composite Reinforced by ZTA Particles in Impact Abrasion

    Science.gov (United States)

    Qiu, B.; Xing, S. M.; Dong, Q.

    2017-11-01

    Zirconia toughened alumina (ZTA) particles reinforced high chromium cast iron composites (ZTA/Iron composites) were prepared by a two-step processing method, i.e. mixing particles by the molten metal and cohering by high pressure, which based on the squeeze casting process. The impact wear resistance under different impact energies were investigated using dynamically loaded abrasive wear tester at room temperature. For comparison, the wear tests of high chromium cast iron were also carried out under the same conditions. Worn surfaces of the samples were observed under scanning electron microscopy equipped with an energy dispersive detector. The results showed that the composites have better impact wear resistance than that of high Cr cast iron regardless of impact energy level, and the wear resistance of the two materials all decrease with the increase of the impact energy. The main wear mechanisms of the high Cr cast iron were micro-cutting and fatigue peeling, while the wear of composites occurred through micro-cutting of the matrix (lower impact energy) and breaking and shedding of the reinforced particles (higher impact energy).

  5. Core–shell composite particles composed of biodegradable polymer particles and magnetic iron oxide nanoparticles for targeted drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Oka, Chiemi; Ushimaru, Kazunori [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Horiishi, Nanao [Bengala Techno Laboratory, 9-5-1006, 1-1 Kodai, Miyamae-ku, Kawasaki 216-0007 (Japan); Tsuge, Takeharu [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Kitamoto, Yoshitaka, E-mail: kitamoto.y.aa@m.titech.ac.jp [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

    2015-05-01

    Core–shell composite particles with biodegradability and superparamagnetic behavior were prepared using a Pickering emulsion for targeted drug delivery based on magnetic guidance. The composite particles were composed of a core of biodegradable polymer and a shell of assembled magnetic iron oxide nanoparticles. It was found that the dispersibility of the nanoparticles is crucial for controlling the core–shell structure. The addition of a small amount of dispersant into the nanoparticle's suspension could improve the dispersibility and led to the formation of composite particles with a thin magnetic shell covering a polymeric core. The composite particles were also fabricated with a model drug loaded into the core, which was released via hydrolysis of the core under strong alkaline conditions. Because the core can also be biodegraded by lipase, this result suggests that the slow release of the drug from the composite particles should occur inside the body. - Highlights: • Core−shell composites with biodegradability and magnetism are prepared. • O/W emulsion stabilized by iron oxide nanoparticles is utilized for the preparation. • The nanoparticle's dispersibility is crucial for controlling the composite structure. • Composites loading a model drug are also prepared. • The model drug is released with decomposition of the composites.

  6. Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

    Science.gov (United States)

    Martin, Patrick; van der Loeff, Michiel Rutgers; Cassar, Nicolas; Vandromme, Pieter; d'Ovidio, Francesco; Stemmann, Lars; Rengarajan, R.; Soares, Melena; González, Humberto E.; Ebersbach, Friederike; Lampitt, Richard S.; Sanders, Richard; Barnett, Bruce A.; Smetacek, Victor; Naqvi, S. Wajih A.

    2013-09-01

    closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to ≥0.40. Silicic acid (artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC m-2 d-1, probably ±20%. 234Th profiles implied constant export of 6.3 mmol POC m-2 d-1 in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.

  7. High prevalence of sub-microscopic infections in Colombia.

    Science.gov (United States)

    Vallejo, Andres F; Chaparro, Pablo E; Benavides, Yoldy; Álvarez, Álvaro; Quintero, Juan Pablo; Padilla, Julio; Arévalo-Herrera, Myriam; Herrera, Sócrates

    2015-05-15

    Malaria transmission in Latin America is typically characterized as hypo-endemic and unstable with ~170 million inhabitants at risk of malaria infection. Although Colombia has witnessed an important decrease in malaria transmission, the disease remains a public health problem with an estimated ~10 million people currently living in areas with malaria risk and ~61,000 cases reported in 2012. This study aimed to establish the malaria prevalence in three endemic regions of Colombia to aid in designing new interventions for malaria elimination. A cross-sectional survey was conducted in three regions of Colombia with different malaria epidemiological profiles: Tierralta (Ta), Tumaco (Tu) and Buenaventura (Bv). The Annual Parasite Index (API) was 10.7, 6.9 and 3.1, respectively. Participants were asked to respond to a sociodemographic questionnaire and then were bled to determine the Duffy genotype and the prevalence of malaria infection by microscopy and quantitative real-time PCR (qPCR). The study was conducted between October 2011 and January 2012. Eight sentinel sites with 1,169 subjects from 267 households were included. The overall prevalence of sub-microscopic infections measured by thick blood smear (TBS) was 0.3% (n=4) whereas by qPCR it was 9.7% (n=113), with a greater proportion (13%) in 40-50 years old individuals. Furthermore, different regions displayed different prevalence of sub-microscopic infections: Bv 12%, Ta 15%, and Tu 4%. From these 113 samples (qPCR), 74% were positive for P. vivax and 22% for P. falciparum, and 4% were mixed infections, which correlates to the overall parasite prevalence in Colombia. This study showed that in the southern Pacific coast of Colombia (Bv and Tu), around 56% of the population have a Duffy-negative genotype, compared to the northern region (Ta) where the percentage of Duffy-negative genotype is around 3%. Sub-microscopic infections are prevalent across different regions in Colombia, particularly in areas with

  8. Nanoencapsulation of ultra-small superparamagnetic particles of iron oxide into human serum albumin nanoparticles

    Directory of Open Access Journals (Sweden)

    Matthias G. Wacker

    2014-11-01

    Full Text Available Human serum albumin nanoparticles have been utilized as drug delivery systems for a variety of medical applications. Since ultra-small superparamagnetic particles of iron oxide (USPIO are used as contrast agents in magnetic resonance imaging, their encapsulation into the protein matrix enables the synthesis of diagnostic and theranostic agents by surface modification and co-encapsulation of active pharmaceutical ingredients. The present investigation deals with the surface modification and nanoencapsulation of USPIO into an albumin matrix by using ethanolic desolvation. Particles of narrow size distribution and with a defined particle structure have been achieved.

  9. Preparation and characterization of silica coated iron oxide magnetic nano-particles.

    Science.gov (United States)

    Li, Ying-Sing; Church, Jeffrey S; Woodhead, Andrea L; Moussa, Filsun

    2010-09-01

    Iron oxide magnetic nano-particles have been prepared by precipitation in an aqueous solution of iron(II) and iron(III) chlorides under basic condition. Surface modifications have been carried out by using tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS). The uncoated and coated particles have been characterized with transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, thermal gravimetric analysis (TGA), and infrared (IR) and Raman spectroscopy. The particle sizes as measured from TEM images were found to have mean diameters of 13nm for the uncoated and about 19nm for the coated particles. The measured IR spectra of the uncoated and MPTMS coated particles showed the conversion of magnetite to hematite at high temperature. The results obtained from both IR spectroscopy and TGA revealed that the mercaptopropylsilyl group in the MPTMS coated magnetite decomposed at 600 degrees C and the silica layer of the TEOS coated magnetite was rather stable. Raman spectroscopy has shown the laser heating effect through the conversion of magnetite to maghemite and hematite. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Hybrid Adsorptive and Oxidative Removal of Natural Organic Matter Using Iron Oxide-Coated Pumice Particles

    Directory of Open Access Journals (Sweden)

    Sehnaz Sule Kaplan Bekaroglu

    2016-01-01

    Full Text Available The aim of this work was to combine adsorptive and catalytic properties of iron oxide surfaces in a hybrid process using hydrogen peroxide and iron oxide-coated pumice particles to remove natural organic matter (NOM in water. Experiments were conducted in batch, completely mixed reactors using various original and coated pumice particles. The results showed that both adsorption and catalytic oxidation mechanisms played role in the removal of NOM. The hybrid process was found to be effective in removing NOM from water having a wide range of specific UV absorbance values. Iron oxide surfaces preferentially adsorbed UV280-absorbing NOM fractions. Furthermore, the strong oxidants produced from reactions among iron oxide surfaces and hydrogen peroxide also preferentially oxidized UV280-absorbing NOM fractions. Preloading of iron oxide surfaces with NOM slightly reduced the further NOM removal performance of the hybrid process. Overall, the results suggested that the tested hybrid process may be effective for removal of NOM and control disinfection by-product formation.

  11. Combined in situ zymography, immunofluorescence, and staining of iron oxide particles in paraffin-embedded, zinc-fixed tissue sections.

    Science.gov (United States)

    Haeckel, Akvile; Schoenzart, Lena; Appler, Franziska; Schnorr, Joerg; Taupitz, Matthias; Hamm, Bernd; Schellenberger, Eyk

    2012-01-01

    Superparamagnetic iron oxide particles are used as potent contrast agents in magnetic resonance imaging. In histology, these particles are frequently visualized by Prussian blue iron staining of aldehyde-fixed, paraffin-embedded tissues. Recently, zinc salt-based fixative was shown to preserve enzyme activity in paraffin-embedded tissues. In this study, we demonstrate that zinc fixation allows combining in situ zymography with fluorescence immunohistochemistry (IHC) and iron staining for advanced biologic investigation of iron oxide particle accumulation. Very small iron oxide particles, developed for magnetic resonance angiography, were applied intravenously to BALB/c nude mice. After 3 hours, spleens were explanted and subjected to zinc fixation and paraffin embedding. Cut tissue sections were further processed to in situ zymography, IHC, and Prussian blue staining procedures. The combination of in situ zymography as well as IHC with subsequent Prussian blue iron staining on zinc-fixed paraffin-embedded tissues resulted in excellent histologic images of enzyme activity, protease distribution, and iron oxide particle accumulation. The combination of all three stains on a single section allowed direct comparison with only moderate degradation of fluorescein isothiocyanate-labeled substrate. This protocol is useful for investigating the biologic environment of accumulating iron oxide particles, with excellent preservation of morphology.

  12. Combined in Situ Zymography, Immunofluorescence, and Staining of Iron Oxide Particles in Paraffin-Embedded, Zinc-Fixed Tissue Sections

    Directory of Open Access Journals (Sweden)

    Eyk Schellenberger

    2012-09-01

    Full Text Available Superparamagnetic iron oxide particles are used as potent contrast agents in magnetic resonance imaging. In histology, these particles are frequently visualized by Prussian blue iron staining of aldehyde-fixed, paraffin-embedded tissues. Recently, zinc salt-based fixative was shown to preserve enzyme activity in paraffin-embedded tissues. In this study, we demonstrate that zinc fixation allows combining in situ zymography with fluorescence immunohistochemistry (IHC and iron staining for advanced biologic investigation of iron oxide particle accumulation. Very small iron oxide particles, developed for magnetic resonance angiography, were applied intravenously to BALB/c nude mice. After 3 hours, spleens were explanted and subjected to zinc fixation and paraffin embedding. Cut tissue sections were further processed to in situ zymography, IHC, and Prussian blue staining procedures. The combination of in situ zymography as well as IHC with subsequent Prussian blue iron staining on zinc-fixed paraffin-embedded tissues resulted in excellent histologic images of enzyme activity, protease distribution, and iron oxide particle accumulation. The combination of all three stains on a single section allowed direct comparison with only moderate degradation of fluorescein isothiocyanate–labeled substrate. This protocol is useful for investigating the biologic environment of accumulating iron oxide particles, with excellent preservation of morphology.

  13. Effect of Iron-Containing Intermetallic Particles on the Corrosion Behaviour of Aluminium

    DEFF Research Database (Denmark)

    Ambat, Rajan

    2006-01-01

    The effect of heat treatment on the corrosion behaviour of binary Al-Fe alloys containing iron at levels between 0.04 and 0.42 wt.% was investigated by electrochemical measurements in both acidic and alkaline chloride solutions. Comparing solution heat-treated and quenched materials with samples...... with {100} facets, and are observed to contain numerous intermetallic particles. Fine facetted filaments also radiate out from the periphery of pits. The results demonstrate that the corrosion of "pure" 99.96% Al is thus dominated by the role of iron, which is the main impurity, and its electrochemical...

  14. Structure and magnetic properties of iron-platinum particles with iron oxide shell.

    Energy Technology Data Exchange (ETDEWEB)

    Basit, Lubna; Shukoor, Ibrahim; Ksenofontov, Vadim; Tremel, Wolfgang; Fecher, Gerhard H.; Felser, Claudia [Institut of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz (Germany); Nepijko, Sergei A.; Schoenhense, Gerd [Institut of Physics, Johannes Gutenberg - University, 55099 Mainz (Germany); Klimenkov, Michael [Institut of Materials Research I, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany)

    2008-07-01

    Nanoparticles of solid solution Fe{sub x}Pt{sub 1-x}, where 0.25{>=}x {>=}0 with Fe{sub 2}O{sub 3} shell were synthesized and characterized by high-resolution transmission electron microscopy, energy dispersive X-ray analysis, electron energy loss spectroscopy, Moessbauer spectroscopy and magnetometry. The magnetic properties, of such two-phase particles are interesting because their core is antiferromagnetic or paramagnetic (at very small values of x) whereas the shell is ferrimagnetic. The size of the particles was in the range of several nanometers. {sup 57}Fe Moessbauer spectroscopy revealed a blocking temperature of about 100 K above which the particles are superparamagnetic. Towards lower temperatures, the magnetic characteristics showed an increase of magnetic rigidity. The saturation magnetization increases by a factor of 1.4 between room temperature and 5 K.

  15. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Adam Crawford; Burtron H. Davis

    2006-09-30

    In the previous reporting period, modifications were completed for integrating a continuous wax filtration system for a 4 liter slurry bubble column reactor. During the current reporting period, a shakedown of the system was completed. Several problems were encountered with the progressive cavity pump used to circulate the wax/catalyst slurry though the cross-flow filter element and reactor. During the activation of the catalyst with elevated temperature (> 270 C) the elastomer pump stator released sulfur thereby totally deactivating the iron-based catalyst. Difficulties in maintaining an acceptable leak rate from the pump seal and stator housing were also encountered. Consequently, the system leak rate exceeded the expected production rate of wax; therefore, no online filtration could be accomplished. Work continued regarding the characterization of ultra-fine catalyst structures. The effect of carbidation on the morphology of iron hydroxide oxide particles was the focus of the study during this reporting period. Oxidation of Fe (II) sulfate results in predominantly {gamma}-FeOOH particles which have a rod-shaped (nano-needles) crystalline structure. Carbidation of the prepared {gamma}-FeOOH with CO at atmospheric pressure produced iron carbides with spherical layered structure. HRTEM and EDS analysis revealed that carbidation of {gamma}-FeOOH particles changes the initial nano-needles morphology and generates ultrafine carbide particles with irregular spherical shape.

  16. Effect of iron-containing intermetallic particles on the corrosion behaviour of aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Ambat, Rajan [Department of Manufacturing and Management, Technical University of Denmark, DK 2800 Kgs. Lyngby (Denmark)]. E-mail: ambat@ipl.dtu.dk; Davenport, Alison J. [Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Scamans, Geoff M. [Innoval Technology Limited, Banbury, Oxfordshire (United Kingdom); Afseth, Andreas [Alcan Technology and Management, CH-8212 Neuhausen (Switzerland)

    2006-11-15

    The effect of heat treatment on the corrosion behaviour of binary Al-Fe alloys containing iron at levels between 0.04 and 0.42 wt.% was investigated by electrochemical measurements in both acidic and alkaline chloride solutions. Comparing solution heat-treated and quenched materials with samples that had been subsequently annealed to promote precipitation of Al{sub 3}Fe intermetallic particles, it was found that annealing increases both the cathodic and anodic reactivity. The increased cathodic reactivity is believed to be directly related to the increased available surface area of the iron-containing intermetallic particles acting as preferential sites for oxygen reduction and hydrogen evolution. These particles also act as pit initiation sites. Heat treatment also causes depletion in the solute content of the matrix, increasing its anodic reactivity. When breakdown occurs, crystallographic pits are formed with {l_brace}1 0 0{r_brace} facets, and are observed to contain numerous intermetallic particles. Fine facetted filaments also radiate out from the periphery of pits. The results demonstrate that the corrosion of aluminium is thus influenced by the presence of low levels of iron, which is one of the main impurities, and its electrochemical behaviour can be controlled by heat treatment.

  17. Microstructure and hardness of WC-Co particle reinforced iron matrix surface composite

    Directory of Open Access Journals (Sweden)

    Zhang Peng

    2013-11-01

    Full Text Available In this study, a high Cr cast iron surface composite material reinforced with WC-Co particles 2-6 mm in size was prepared using a pressureless sand mold infiltration casting technique. The composition, microstructure and hardness were determined by means of energy dispersive spectrometry (EDS, electron probe microanalysis (EPMA, scanning electron microscope (SEM and Rockwell hardness measurements. It is determined that the obtained composite layer is about 15 mm thick with a WC-Co particle volumetric fraction of ~38%. During solidification, interface reaction takes place between WC-Co particles and high chromium cast iron. Melting and dissolving of prefabricated particles are also found, suggesting that local Co melting and diffusion play an important role in promoting interface metallurgical bonding. The composite layer is composed of ferrite and a series of carbides, such as (Cr, W, Fe23C6, WC, W2C, M6C and M12C. The inhomogeneous hardness in the obtained composite material shows a gradient decrease from the particle reinforced metal matrix composite layer to the matrix layer. The maximum hardness of 86.3 HRA (69.5 HRC is obtained on the particle reinforced surface, strongly indicating that the composite can be used as wear resistant material.

  18. Effect of the Lifting Velocity and Container Shape on Angle of Repose of Iron Ore Particles

    Directory of Open Access Journals (Sweden)

    Tongqing Li

    2017-01-01

    Full Text Available To investigate the impact of lifting velocity and container shape on angle of repose, the fixed-base cylinder method was performed using three types of container shape. The container shape was lifted a series of lifting velocities. Six size fractions of iron ore particles ranging from coarser to fine particles were used as the test materials. And the sand-pile calibration method was then used to calibrate the contact parameters of iron ore particles. Results show angle of repose decreased exponentially with the lifting velocity, while it appeared approximately to be invariant to particle shape, for all size fractions. The sand pile highly depends on the container shape at a low lifting velocity but appears to be invariant to particle size for a high lifting velocity. And then a predictive equation is established and a very close agreement between the predicted and measured angle of repose is attained. Finally, a series of DEM simulations considering the irregular particle shape are conducted by means of sphere clump method to calibrate the contact parameters and are in good visual agreement with the experimental results, indicating the “tuned” contact parameters as well as the applicability of the predicted equation.

  19. Alternative Frameworks of the Secondary School Students on the Concept of Condensation at Submicroscopic Level

    Science.gov (United States)

    Abdullah, Nurdiana; Surif, Johari; Ismail, Syuhaida

    2016-01-01

    The study was carried out to identify the alternative frameworks on the concept of condensation at submicroscopic level among secondary school students (N = 324). Data was collected by using the qualitative method through the Understanding Test on the Concept of Matter at Submicroscopic Level which consisted of 10 open-ended questions. The…

  20. The Effect of Different Textual Narrations on Students' Explanations at the Submicroscopic Level in Chemistry

    Science.gov (United States)

    Al-Balushi, Sulaiman M.

    2013-01-01

    The effect of different textual versions (macroscopic (control), submicroscopic, and guided imagery) of the explanation of a chemical phenomenon on students' submicroscopic explanation of a related phenomenon was examined. The sample included 152 pre-service science teachers. The three textual versions of the explanation were distributed randomly…

  1. 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 ...

  2. Low dose inflammatory potential of silica particles in human-derived THP-1 macrophage cell culture studies - Mechanism and effects of particle size and iron.

    Science.gov (United States)

    Premshekharan, Gayatri; Nguyen, Kennedy; Zhang, Hongqiao; Forman, Henry Jay; Leppert, Valerie Jean

    2017-06-25

    Silica and iron are major constituents in ambient particulate matter, and iron is a common impurity in many engineered nanomaterials. The purpose of this work was to determine the pro-inflammatory and other biological effects and mechanism of particle size and iron presence under low dose, non-cytotoxic conditions that are likely to approximate actual exposure levels, in contrast with higher dose studies in which cytotoxicity occurs. Specifically, human-derived THP-1 macrophages were exposed to 1 μg/ml of pristine and iron-coated 50 nm and 2 μm engineered silica nanoparticles. Particles were first characterized for size, size distribution, surface area, iron concentration, phase and aggregation in cell culture media. Then, biological assays were conducted to determine a non-lethal dose used in subsequent experiments. Superoxide production, lipid peroxidation, and increased pro-inflammatory cytokine (TNF-α and IL-1β) mRNA expression were measured as a function of particle size and iron presence. Smaller particle size and the presence of iron increased superoxide production, lipid peroxidation, and the induction of pro-inflammatory cytokine mRNA expression. Separate addition of an iron-chelator, a scavenger of superoxide and hydrogen peroxide, and an inhibitor of phosphatidylcholine specific phospholipase C (PC-PLC), suppressed the increase in cytokine mRNA expression. Furthermore, free iron itself showed none of the aforementioned effects. The results highlight the importance of particle size and iron in lung inflammation for both natural and engineered nanomaterials, under low dose, non-toxic conditions, and support the role of an oxidant, lipid peroxidation and PC-PLC dependent inflammatory mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. SEMI-ACTIVE DAMPING PERFORMANCE OF IRON PARTICLE FILLED SILICONE RUBBER

    Directory of Open Access Journals (Sweden)

    Florian Dirisamer

    2016-02-01

    Full Text Available The aim of this work was to design, produce and evaluate a demonstrator to visualize the magneto-induced damping behaviour of materials. In contrast to standard materials, the damping coefficient of iron particle filled silicone rubbers can be controlled by a semi-active magnetic field. This field effect should be characterized in order to evaluate the suitability of these magnetorheological silicone elastomers for the use in different configurations and applications.

  4. Cellular Precipitates Of Iron Oxide in Olivine in a Stratospheric Interplanetary Dust Particle

    Science.gov (United States)

    Rietmeijer, Frans J. M.

    1996-01-01

    The petrology of a massive olivine-sulphide interplanetary dust particle shows melting of Fe,Ni-sulphide plus complete loss of sulphur and subsequent quenching to a mixture of iron-oxides and Fe,Ni-metal. Oxidation of the fayalite component in olivine produced maghemite discs and cellular intergrowths with olivine and rare andradite-rich garnet. Cellular reactions require no long-range solid-state diffusion and are kinetically favourable during pyrometamorphic oxidation. Local melting of the cellular intergrowths resulted in three dimensional symplectic textures. Dynamic pyrometamorphism of this asteroidal particle occurred at approx. 1100 C during atmospheric entry flash (5-15 s) heating.

  5. Pb2+ ions mobility perturbation by iron particles during electrokinetic remediation of contaminated soil.

    Science.gov (United States)

    Zulfiqar, Waqas; Iqbal, Muhammad Asad; Butt, Mehwish Khalid

    2017-02-01

    Electrokinetic (EK) remediation is one of the most useful approaches for de-contamination of soils. However, it is unclear that how and when the electrokinetic remediation gives advantages over other remediation techniques in soil. This study was designed to find the influence of Fe2+ particles on the mobility of Pb2+ ions, during electrokinetic remediation, in soil contaminated purposely by lead nitrate Pb(NO3)2. Two types of electrokinetic experiments were performed, by using iron and graphite electrodes. The Fe2+ ions from the iron electrodes, produced due to acidic environment in anode compartment, affected the mobility of lead particles by precipitating as Fe(OH)2. Fe2+ ions enhance the adsorption of lead ions in soil. The results show Fe2+ ions of lower ionic conductivity decreased mobility of other particles in soil. Electrokinetic remediation for up to 120 h with iron electrodes is shown to be less effective for removal of lead. In contrast, graphite electrodes were 15 times more effective in lead removal from soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. A study of the initiator concentration’s effect on styrene-divinylbenzene polymerization with iron particles

    Directory of Open Access Journals (Sweden)

    Bárbara M. da Conceição

    2011-01-01

    Full Text Available This paper describes the preparation of magnetic copolymer obtained from suspension polymerization of styrene (Sty and divinylbenzene (DVB in the presence of iron particles treated and not treated with oleic acid. The magnetic copolymers were characterized according to their morphology, particle size distribution and magnetic properties. The results show that incorporation of iron particles significantly changed the particles’ morphology. All samples presented higher saturation magnetization than the values reported in the literature and the particle size distribution was more monodisperse when the polymerization was conducted with 5%wt of benzoyl peroxide (BPO.

  7. Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles

    Science.gov (United States)

    Li, Yi; Xu, Ben; Hu, Shenyang; Li, Yulan; Li, Qiulin; Liu, Wei

    2015-07-01

    The magnetic hysteresis loops and Barkhausen noise of a single α-iron with nonmagnetic particles are simulated to investigate into the magnetic hardening due to Cu-rich precipitates in irradiated reactor pressure vessel (RPV) steels. Phase field method basing Landau-Lifshitz-Gilbert (LLG) equation is used for this simulation. The results show that the presence of the nonmagnetic particle could result in magnetic hardening by making the nucleation of reversed domains difficult. The coercive field is found to increase, while the intensity of Barkhausen noise voltage is decreased when the nonmagnetic particle is introduced. Simulations demonstrate the impact of nucleation field of reversed domains on the magnetization reversal behavior and the magnetic properties.

  8. Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Li, Qiulin; Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [School of Material Science and Engineering, Tsinghua University, Beijing, 100084 (China); Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055 (China); Xu, Ben [School of Material Science and Engineering, Tsinghua University, Beijing, 100084 (China); Hu, Shenyang; Li, Yulan [Energy Materials Division, Pacific Northwest National Laboratory, Richland, WA, 99352 (United States)

    2015-07-15

    The magnetic hysteresis loops and Barkhausen noise of a single α-iron with nonmagnetic particles are simulated to investigate into the magnetic hardening due to Cu-rich precipitates in irradiated reactor pressure vessel (RPV) steels. Phase field method basing Landau-Lifshitz-Gilbert (LLG) equation is used for this simulation. The results show that the presence of the nonmagnetic particle could result in magnetic hardening by making the nucleation of reversed domains difficult. The coercive field is found to increase, while the intensity of Barkhausen noise voltage is decreased when the nonmagnetic particle is introduced. Simulations demonstrate the impact of nucleation field of reversed domains on the magnetization reversal behavior and the magnetic properties.

  9. Simulation of magnetic hysteresis loops and magnetic Barkhausen noise of α-iron containing nonmagnetic particles

    Directory of Open Access Journals (Sweden)

    Yi Li

    2015-07-01

    Full Text Available The magnetic hysteresis loops and Barkhausen noise of a single α-iron with nonmagnetic particles are simulated to investigate into the magnetic hardening due to Cu-rich precipitates in irradiated reactor pressure vessel (RPV steels. Phase field method basing Landau-Lifshitz-Gilbert (LLG equation is used for this simulation. The results show that the presence of the nonmagnetic particle could result in magnetic hardening by making the nucleation of reversed domains difficult. The coercive field is found to increase, while the intensity of Barkhausen noise voltage is decreased when the nonmagnetic particle is introduced. Simulations demonstrate the impact of nucleation field of reversed domains on the magnetization reversal behavior and the magnetic properties.

  10. Lactoferrin conjugated iron oxide nanoparticles for targeting brain glioma cells in magnetic particle imaging

    Science.gov (United States)

    Tomitaka, Asahi; Arami, Hamed; Gandhi, Sonu; Krishnan, Kannan M.

    2015-10-01

    Magnetic Particle Imaging (MPI) is a new real-time imaging modality, which promises high tracer mass sensitivity and spatial resolution directly generated from iron oxide nanoparticles. In this study, monodisperse iron oxide nanoparticles with median core diameters ranging from 14 to 26 nm were synthesized and their surface was conjugated with lactoferrin to convert them into brain glioma targeting agents. The conjugation was confirmed with the increase of the hydrodynamic diameters, change of zeta potential, and Bradford assay. Magnetic particle spectrometry (MPS), performed to evaluate the MPI performance of these nanoparticles, showed no change in signal after lactoferrin conjugation to nanoparticles for all core diameters, suggesting that the MPI signal is dominated by Néel relaxation and thus independent of hydrodynamic size difference or presence of coating molecules before and after conjugations. For this range of core sizes (14-26 nm), both MPS signal intensity and spatial resolution improved with increasing core diameter of nanoparticles. The lactoferrin conjugated iron oxide nanoparticles (Lf-IONPs) showed specific cellular internalization into C6 cells with a 5-fold increase in MPS signal compared to IONPs without lactoferrin, both after 24 h incubation. These results suggest that Lf-IONPs can be used as tracers for targeted brain glioma imaging using MPI.

  11. Ferrioxamine siderophores detected amongst iron binding ligands produced during the remineralization of marine particles

    Directory of Open Access Journals (Sweden)

    Imelda B Velasquez

    2016-09-01

    Full Text Available The microbial degradation of marine particles is an important process in the remineralization of nutrients including iron. As part of the GEOTRACES process study (FeCycle II, we conducted incubation experiments with marine particles obtained from 30 and 100 m depth at two stations during austral spring in the subtropical waters east of the North Island of New Zealand. The particles were collected using in-situ pumps, and comprised mainly of suspended and slow sinking populations along with associated attached heterotrophic bacteria. In treatments with live bacteria, increasing concentrations of Fe binding ligands were observed with an average stability constant of logKFeL,Fe3+ = 21.11±0.37 for station 1 and 20.89±0.25 for station 2. The ligand release rates varied between 2.54 and 11.8 pmol L-1 d-1 (calculated for ambient seawater particle concentration and were similar to those found in two Southern Ocean subsurface studies from ~110 m depths in subpolar and polar waters. Dissolved iron (DFe was released at a rate between 0.33 and 2.09 pmol Fe L-1 d-1 with a column integrated (30 -100 m flux of 107 and 58 nmol Fe m-2 day-1 at station 1 and 2, respectively. Given a mixed layer DFe inventory of ~48 µmol m-2 and ~4 µmol m-2 at the time of sampling for station 1 and 2, this will therefore result in a DFe residence time of 1.2 and 0.18 years, assuming particle remineralization was the only source of iron in the mixed layer. The DFe release rates calculated were comparable to those found in the previously mentioned study of Southern Ocean water masses. Fe-binding ligand producing bacteria (CAS positive abundance was found to increase throughout the duration of the experiment of 7 to 8 days. For the first time ferrioxamine type siderophores, including the well-known ferrioxamine B and G, have been quantified using chemical assays and LC-ESI-MS. Our subtropical study corroborates prior reports from the Southern Ocean of particle remineralization

  12. Ecotoxicity of nanoscale zero-valent iron particles – a review

    Directory of Open Access Journals (Sweden)

    José Tomás Albergaria

    2013-11-01

    Full Text Available The use of nanoscale zero-valent iron particles (nZVIs in the environmental remediation of water and soil is increasing. This increase is related to the higher reactivity and mobility of nZVIs compared with that of macro- or micro-sized iron particles. The introduction of nZVIs into the environment raises concerns related to their fate and effect on aquatic and terrestrial biota. Knowledge of these issues will allow a better understanding not only of the remediation process but also of the long-term effects and impact of nZVIs on ecosystems, leading to a safer and more efficient application of these particles. This paper presents the current state of play concerning the toxic effects of nZVIs on organisms at different stages of the food chain. The majority of studies show that nZVIs have a negative impact on bacteria, aquatic invertebrates, such as Daphnia mag-na, terrestrial organisms, such as Eisenia fetida, and seed germination. However, the number of published studies related to this issue is clearly insufficient. This reinforces the need for further research in order to specify the toxic concentrations of nZVIs that affect the most important target organisms. Furthermore, an evaluation of the effects of the coating of nanoparticles should also be pursued

  13. 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...

  14. Effect of macrofauna, oxygen exchange and particle reworking on iron and manganese sediment gogeochemistry: a laboratory experiment

    NARCIS (Netherlands)

    Ferro, I.; Van Nugteren, P.; Middelburg, J.J.; Herman, P.M.J.; Heip, C.H.R.

    2003-01-01

    The impact of bioturbation on iron and manganese cycling in rine sediments was studied in laboratory experiments in which faunal effects which combine in the field (particle mixing and oxygen exchange) were studied separately. Particle mixing and sediment aeration both enhance metal oxide reduction

  15. Iron oxide nanoparticle-micelles (ION-micelles) for sensitive (molecular) magnetic particle imaging and magnetic resonance imaging

    NARCIS (Netherlands)

    Starmans, Lucas W. E.; Burdinski, Dirk; Haex, Nicole P. M.; Moonen, Rik P. M.; Strijkers, Gustav J.; Nicolay, Klaas; Grüll, Holger

    2013-01-01

    Iron oxide nanoparticles (IONs) are a promising nanoplatform for contrast-enhanced MRI. Recently, magnetic particle imaging (MPI) was introduced as a new imaging modality, which is able to directly visualize magnetic particles and could serve as a more sensitive and quantitative alternative to MRI.

  16. Synthesis and Properties of Iron Oxide Particles Prepared by Hidrothermal Method

    Science.gov (United States)

    Saragi, T.; Santika, A. S.; Permana, B.; Syakir, N.; Kartawidjaja, M.; Risdiana

    2017-05-01

    Iron oxide of hematite (α-Fe2O3) has been successfully synthesized by hydrothermal method. The starting materials were Fe(NO3)3.9H2O, 2-methoxyethanol, diethanolamine and n-hexane. The optical, morphology and crystal structure were measured by UV-VIS, TEM and XRD, respectively. From UV-VIS measurement, it was found that the band-gap of sample was 4.17 eV. The morphology of particle was plate-like form. The sample which sintered at 1100°C has high quality crystal with hexagonal structure of α-Fe2O3 phase.

  17. Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical reactivity.

    Science.gov (United States)

    Schneider, J J; Czap, N; Hagen, J; Engstler, J; Ensling, J; Gütlich, P; Reinoehl, U; Bertagnolli, H; Luis, F; de Jongh, L J; Wark, M; Grubert, G; Hornyak, G L; Zanoni, R

    2000-12-01

    Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mössbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mössbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From Mössbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO2 nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO2 (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2 nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe2O3 and TiO2 according to experimental binding energies and the experimental line shapes. Ti4+ and Fe3+ are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degrees C under flowing H2/N2 produces a catalyst, which is active

  18. 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

  19. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2006-03-31

    The morphological and chemical nature of ultrafine iron catalyst particles (3-5 nm diameters) during activation/FTS was studied by HRTEM, EELS, and Moessbauer spectroscopy. With the progress of FTS, the carbide re-oxidized to magnetite and catalyst activity gradually decreased. The growth of oxide phase continued and average particle size also increased simultaneously. The phase transformation occurred in a ''growing oxide core'' manner with different nano-zones. The nano-range carbide particles did not show fragmentation or attrition as generally observed in micrometer range particles. Nevertheless, when the dimension of particles reached the micrometer range, the crystalline carbide phase appeared to be sprouted on the surface of magnetite single crystal. In the previous reporting period, a design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. During the current reporting period, we have started construction of the new filtration system and began modifications to the 4 liter slurry bubble column reactor (SBCR) reactor. The system will utilize a primary wax separation device followed by a Pall Accusep or Membralox ceramic cross-flow membrane. As of this writing, the unit is nearly complete except for the modification of a moyno-type pump; the pump was shipped to the manufacturer to install a special leak-free, high pressure seal.

  20. Elemental analysis of lung tissue particles and intracellular iron content of alveolar macrophages in pulmonary alveolar proteinosis

    Directory of Open Access Journals (Sweden)

    Ohkubo Takeru

    2011-06-01

    Full Text Available Abstract Background Pulmonary alveolar proteinosis (PAP is a rare disease occurred by idiopathic (autoimmune or secondary to particle inhalation. The in-air microparticle induced X-ray emission (in-air micro-PIXE system performs elemental analysis of materials by irradiation with a proton microbeam, and allows visualization of the spatial distribution and quantitation of various elements with very low background noise. The aim of this study was to assess the secondary PAP due to inhalation of harmful particles by employing in-air micro-PIXE analysis for particles and intracellular iron in parafin-embedded lung tissue specimens obtained from a PAP patient comparing with normal lung tissue from a non-PAP patient. The iron inside alveolar macrophages was stained with Berlin blue, and its distribution was compared with that on micro-PIXE images. Results The elements composing particles and their locations in the PAP specimens could be identified by in-air micro-PIXE analysis, with magnesium (Mg, aluminum (Al, silicon (Si, phosphorus (P, sulfur (S, scandium (Sc, potassium (K, calcium (Ca, titanium (Ti, chromium (Cr, copper (Cu, manganase (Mn, iron (Fe, and zinc (Zn being detected. Si was the major component of the particles. Serial sections stained by Berlin blue revealed accumulation of sideromacrophages that had phagocytosed the particles. The intracellular iron content of alveolar macrophage from the surfactant-rich area in PAP was higher than normal lung tissue in control lung by both in-air micro-PIXE analysis and Berlin blue staining. Conclusion The present study demonstrated the efficacy of in-air micro-PIXE for analyzing the distribution and composition of lung particles. The intracellular iron content of single cells was determined by simultaneous two-dimensional and elemental analysis of paraffin-embedded lung tissue sections. The results suggest that secondary PAP is associated with exposure to inhaled particles and accumulation of iron in

  1. Submicroscopic chromosomal abnormalities in fetuses with increased nuchal translucency and normal karyotype.

    Science.gov (United States)

    Yang, Xin; Li, Ru; Fu, Fang; Zhang, Yongling; Li, Dongzhi; Liao, Can

    2017-01-01

    To investigate the submicroscopic chromosomal abnormalities in fetuses with increased nuchal translucency (NT) and normal karyotype. Total of 296 fetuses with increased NT (≥3.0 mm) were tested by conventional karyotyping. When cytogenetic analysis showed normal chromosome, the pregnancies were then consulted for array-comparative genomic hybridization (CGH) analysis and received subsequent morphology scan between 20 and 24 weeks gestation. Submicroscopic chromosomal abnormalities were assessed and compared between the fetuses with and without structural defects. Chromosomal abnormality was identified in 19.9% (59/296) fetuses. Two hundred and twenty samples were tested by array CGH. Submicroscopic chromosomal abnormalities were detected in 9.1% (20/220) fetuses. For the fetuses with abnormal morphology scan, the detection rate of submicroscopic chromosomal abnormalities was higher than those with normal morphology scan (26.9% versus 6.7%, p karyotype, especially when the structural defects were found at second or third trimester.

  2. Evaluating Trichloroethylene Degradation Using Differing Nano- and Micro-Scale Iron Particles

    Science.gov (United States)

    Berger, Cristina M.; Geiger, Cherie L.; Clausen, Christian A.; Billow, Alexa M.; Quinn, Jacqueline W.; Brooks, Kathleen B.

    2006-01-01

    Trichioroethylene, or TCE, is a central nervous system depressant and possible carcinogen, as well as a persistent groundwater pollutant. TCE exists in the aquifer either as free product in the form of a dense non-aqueous phase liquid (DNAPL) or as a dissolved-phase constituent. It is only slightly soluble in water, so dissolution of the contaminant is a long-term process and in-situ remediation is difficult. To remedy this, NASA and the University of Central Florida developed Emulsified Zero-Valent Iron, or EZVI. The emulsion droplet contains ZVI particles and water encapsulated by an oil/surfactant membrane, and effectively penetrates to degrade DNAPL-phase TCE. To maximize the efficiency of this process, several commercially available ZVIs of radically different particle sizes and morphologies both in emulsion and as neat (unemulsified) metal were evaluated for relative effectiveness at TCE degradation.

  3. Identification of Mg2Cu particles in Cu-alloyed austempered ductile iron

    Science.gov (United States)

    Górny, Marcin; Tyrała, Edward; Sikora, Gabriela; Rogal, Łukasz

    2018-01-01

    In the present work, the Mg2Cu precipitates in copper-alloyed austempered ductile iron (ADI) were identified by analyzing techniques such as TEM and SEM with EDS. It was revealed that, in castings made of ADI-containing copper, highly dispersed particles of Mg2Cu are formed, whose size does not exceed TEM. In addition to this, the exhibited impact properties of castings with Cu, Ni, and Cu+Ni were also determined. This study casts a new light on the formation of the structure of Cu-alloyed ADI. The highly-dispersive and brittle Mg2Cu particles that are located in the vicinity of the graphite nodules have a negative effect on the impact properties of ADI. It has also been shown that impact strength decreases from levels of 160-180 J (for copper-free ADI) to 90-120 J (for copper-and copper-nickel-alloyed ADI).

  4. Iron particle and anisotropic effects on mechanical properties of magneto-sensitive elastomers

    Science.gov (United States)

    Kumar, Vineet; Lee, Dong-Joo

    2017-11-01

    Rubber specimens were prepared by mixing micron-sized iron particles dispersed in room-temperature-vulcanized (RTV) silicone rubber by solution mixing. The possible correlations of the particle volume, size, and distribution with the mechanical properties of the specimens were examined. An isotropic mechanical test shows that at 60 phr, the elastic modulus was 3.29 MPa (electrolyte), 2.92 MPa (carbonyl), and 2.61 MPa (hybrid). The anisotropic effect was examined by curing the specimen under magnetic fields of 0.5-2.0 T at 90° relative to the applied strain. The measurements show anisotropic effects of 11% (carbonyl), 9% (electrolyte), and 6% (hybrid) at 40 phr and 1 T. At 80 phr, the polymer-filler compatibility factor (c-factor) was estimated using the Pythagorean theorem as 0.53 (regular) and 0.73 (anisotropic studies). The improved features could be useful in applications such as controlled damping, vibrational absorption, or automotive bushings.

  5. Synthesis, Characterization and Reactivity of Nanostructured Zero-Valent Iron Particles for Degradation of Azo Dyes

    Science.gov (United States)

    Mikhailov, Ivan; Levina, Vera; Leybo, Denis; Masov, Vsevolod; Tagirov, Marat; Kuznetsov, Denis

    Nanostructured zero-valent iron (NSZVI) particles were synthesized by the method of ferric ion reduction with sodium borohydride with subsequent drying and passivation at room temperature in technical grade nitrogen. The obtained sample was characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and dynamic light scattering studies. The prepared NSZVI particles represent 100-200nm aggregates, which consist of 20-30nm iron nanoparticles in zero-valent oxidation state covered by thin oxide shell. The reactivity of the NSZVI sample, as the removal efficiency of refractory azo dyes, was investigated in this study. Two azo dye compounds, namely, orange G and methyl orange, are commonly detected in waste water of textile production. Experimental variables such as NSZVI dosage, initial dye concentration and solution pH were investigated. The kinetic rates of degradation of both dyes by NSZVI increased with the decrease of solution pH from 10 to 3 and with the increase of NSZVI dosage, but decreased with the increase of initial dye concentration. The removal efficiencies achieved for both orange G and methyl orange were higher than 90% after 80min of treatment.

  6. Preparation and characterization of hydroxyapatite-coated iron oxide particles by spray-drying technique

    Directory of Open Access Journals (Sweden)

    karina Donadel

    2009-06-01

    Full Text Available Magnetic particles of iron oxide have been increasingly used in medical diagnosis by magnetic resonance imaging and in cancer therapies involving targeted drug delivery and magnetic hyperthermia. In this study we report the preparation and characterization of iron oxide particles coated with bioceramic hydroxyapatite by spray-drying. The iron oxide magnetic particles (IOMP were coated with hydroxyapatite (HAp by spray-drying using two IOMP/HAp ratios (0.7 and 3.2. The magnetic particles were characterized by way of scanning electronic microscopy, energy dispersive X-ray, X-ray diffraction, Fourier transformed infrared spectroscopy, flame atomic absorption spectrometry,vibrating sample magnetometry and particle size distribution (laser diffraction. The surface morphology of the coated samples is different from that of the iron oxide due to formation of hydroxyapatite coating. From an EDX analysis, it was verified that the surface of the coated magnetic particles is composed only of HAp, while the interior containsiron oxide and a few layers of HAp as expected. The results showed that spray-drying technique is an efficient and relatively inexpensive method for forming spherical particles with a core/shell structure.As partículas de óxido de ferro têm sido extensivamente usadas em diagnósticos médicos como agente de contraste para imagem por ressonância magnética e na terapia do câncer, dentre estas, liberação de fármacos em sitos alvos e hipertermia magnética. Neste estudo nós reportamos a preparação e caracterização de partículas magnéticas de óxido de ferro revestidas com a biocerâmica hidroxiapatita. As partículas magnéticasde óxido de ferro (PMOF foram revestidas com hidroxiapatita por spray-drying usando duas razões PMOF/HAp (0,7 e 3,2. As partículas magnéticas foram caracterizadas por microscopia eletrônica de varredura, energia dispersiva de raios X, difração de raios X, espectroscopia de absorção no infra

  7. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  8. Influencing factors in the CO-precipitation process of superparamagnetic iron oxide nano particles: A model based study

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Hans-Christian; Schwaminger, Sebastian P.; Schindler, Michael [Bioseparation Engineering Group, Technische Universität München, Boltzmannstraße 15, Garching d-85748 (Germany); Wagner, Friedrich E. [Technische Universität München, Physics Department El5, Garching d-85748 (Germany); Berensmeier, Sonja, E-mail: s.berensmeier@tum.de [Bioseparation Engineering Group, Technische Universität München, Boltzmannstraße 15, Garching d-85748 (Germany)

    2015-03-01

    The study, presented here, focuses on the impact of synthesis parameters on the co-precipitation process of superparamagnetic iron oxide nanoparticles. Particle diameters between 3 and 17 nm and saturation magnetizations from 26 to 89 Am{sup 2} kg{sup −1} were achieved by variation of iron salt concentration, reaction temperature, ratio of hydroxide ions to iron ions and ratio of Fe{sup 3+}/Fe{sup 2+}. All synthesis assays were conceived according to the “design of experiments” method. The results were fitted to significant models. Subsequent validation experiments could confirm the models with an accuracy>95%. The characterization of the chemical composition, as well as structural and magnetic properties was carried out using powder X-ray diffraction, transmission electron microscopy, Raman and Mössbauer spectroscopy and superconducting quantum interference device magnetometry. The results reveal that the particles' saturation magnetization can be enhanced by the employment of high iron salt concentrations and a molar ratio of Fe{sup 3+}/Fe{sup 2+} below 2:1. Furthermore, the particle size can be increased by higher iron salt concentrations and a hyperstoichiometric normal ratio of hydroxide ions to iron ions of 1.4:1. Overall results indicate that the saturation magnetization is directly related to the particle size. - Highlights: • We model the impact of synthesis parameters in the Massart process. • Optimization of synthesis parameters according to particle size and magnetization. • Particles are fully characterized with XRD, TEM and SQUID magnetometry.

  9. Degradation of perchloroethene by combined application of microorganisms and zero valent iron particles

    Science.gov (United States)

    Schöftner, Philipp; Summer, Dorothea; Wimmer, Bernhard; Reichenauer, Thomas

    2017-04-01

    Chlorinated hydrocarbons (CHCs) are especially toxic pollutants which are frequently found at contaminated sites in urban areas which are densely covered with buildings. In specific in such areas, in-situ technologies are favourable since conventional remediation technologies as excavation are often not applicable. This project examines a combination of two in-situ remediation methods, in which the biotic degradation via bacteria (dehalococcoides) is combined with abiotic degradation by zero-valent iron particles (ZVI). ZVI particles are injected into the aquifer where CHC-molecules are reductively dechlorinated. However Fe(0) is also oxidized by reaction with water leading to generation of H2 without any CHC degradation. To achieve biotic degradation often strictly anaerobic strains of the bacteria Dehalococcoides are used. These bacteria can dechlorinate CHC by utilizing H2. By combining these processes the H2, produced during the anaerobic corrosion of Fe(0), could be used by bacteria for further CHC degradation. Different Fe(0) particles (nano- and micro-scale) were combined with microbial dehalogenation for dehalogenation of perchloroethene (PCE) in batch experiments. PCE degradation rates and H2 production rates of the different particles and cultures were determined. Additionally an artificial aquifer (approximately 1.0 x 0.5 x 0.5 metres) was established. This aquifer was spiked with PCE and subsequently treated with Fe(0) particles and microbial. Molasses was added to facilitate microbial dehalogenation. Preliminary results showed that all H2 evolved during oxidation of Fe(0) were used by the associated microbial community. Nevertheless the overall dehalogenation of chlorinated compounds as well as the production of methane was hardly influenced by the addition of Fe(0), at least not over the experimental period of 28 days. Independent if Fe(0) was added or not all chlorinated compounds were dehalogenated whereby ethene and ethane were the only end

  10. The structural, magnetic and microwave properties of spherical and flake shaped carbonyl iron particles as thin multilayer microwave absorbers

    Science.gov (United States)

    Khani, Omid; Shoushtari, Morteza Zargar; Ackland, Karl; Stamenov, Plamen

    2017-04-01

    An increase in microwave permeability is a prerequisite for reducing the thickness of radar absorber coatings. The aim of this paper is to increase the magnetic loss of commercial carbonyl iron particles for fabricating wideband microwave absorbers with a multilayer structure. For this purpose, carbonyl iron particles were milled and their static and dynamic magnetic properties were studied before and after milling. A distinct morphological change from spherical to flake-like particles is measured with increased milling time, whereas no distinct changes in magnetic properties are measured with increased milling time. The imaginary part of the permeability (μ״) of the milled carbonyl iron particles increased from 1.23 to 1.88 and showed a very broad peak over the entire frequency range 1-18 GHz. The experimental results were modeled using the Rousselle effective medium theory (EMT) in the Neo formulation. The theoretical predictions showed good agreement with the experimental results. Two layer absorbers were designed according to the measured microwave parameters and the multilayer design. The results revealed that a thin multilayer with a thickness of 1.75 mm can effectively absorb microwaves in both the entire X and Ku frequency bands. The results suggest that microwave absorbers with excellent absorption properties could be mass-produced, using commercial carbonyl iron particles.

  11. Environmental application of millimetre-scale sponge iron (s-Fe{sup 0}) particles (I): Pretreatment of cationic triphenylmethane dyes

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming, E-mail: juyongming@scies.org [South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655 (China); Liu, Xiaowen, E-mail: liuxiaowen@scies.org [South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655 (China); Li, Zhaoyong; Kang, Juan; Wang, Xiaoyan; Zhang, Yukui; Fang, Jiande [South China Institute of Environmental Sciences, the Ministry of Environmental Protection of PRC, Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2015-02-11

    Graphical abstract: - Highlights: • Millimetric s-Fe{sup 0} particles effectively reduce BG, MG, CV, and EV dyes. • s-Fe{sup 0} displays similar contaminant removal efficiency compared to nZVI. • s-Fe{sup 0} shows greater economic advantages than nZVI, iron powder, and iron scurf. • The reductive mechanism of BG over s-Fe{sup 0} under US condition is elucidated. - Abstract: To investigate the removal capability of millimetric zero valent iron (mmZVI), sponge iron (s-Fe{sup 0}) particles were characterized with XRD, XPS, TEM, HRSEM and EDS techniques. Moreover, the roles of particle size, catalyst dosage, dye concentration, mixing conditions (e.g. ultrasound (US), stirring or shaking), and regeneration treatment were studied with the removal of cationic triphenylmethane dyes. Notably, the reduction process was also revealed as compared to nanoscale zero valent iron (nZVI), microscale iron power, and iron scurf. Furthermore, the reductive mechanism was exemplified with brilliant green. The results demonstrated that (1) the synergetic effect between US and s-Fe{sup 0} greatly enhanced the removal of dyes, (2) the dosage of preferred s-Fe{sup 0} (1–3 mm) particles was optimized as 30.0 g/L; (3) reuse cycles of s-Fe{sup 0} catalyst were enhanced with the assistance of diluted HCl solution; (4) the main degradation routes included the cleavage of conjugated structure reactions, N-de-ethylation reactions, hydroxylation reactions, the removal of benzene ring reactions, and opening ring reactions. Accordingly, the pretreatment of aqueous solution over s-Fe{sup 0} was hypothesized to achieve mainly through direct reduction reaction by electron transfer and indirect reductive reactions by the highly activated hydrogen atom. Additionally, decoration with noble metals was utilized to reveal the reaction mechanism.

  12. From oleic acid-capped iron oxide nanoparticles to polyethyleneimine-coated single-particle magnetofectins

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Acuña, Melissa [University of Florida, J. Crayton Pruitt Family Department of Biomedical Engineering (United States); Maldonado-Camargo, Lorena [University of Florida, Department of Chemical Engineering (United States); Dobson, Jon; Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [University of Florida, J. Crayton Pruitt Family Department of Biomedical Engineering (United States)

    2016-09-15

    Various inorganic nanoparticle designs have been developed and used as non-viral gene carriers. Magnetic gene carriers containing polyethyleneimine (PEI), a well-known transfection agent, have been shown to improve DNA transfection speed and efficiency in the presence of applied magnetic field gradients that promote particle–cell interactions. Here we report a method to prepare iron oxide nanoparticles conjugated with PEI that: preserves the narrow size distribution of the nanoparticles, conserves magnetic properties throughout the process, and results in efficient transfection. We demonstrate the ability of the particles to electrostatically bind with DNA and transfect human cervical cancer (HeLa) cells by the use of an oscillating magnet array. Their transfection efficiency is similar to that of Lipofectamine 2000™, a commercial transfection reagent. PEI-coated particles were subjected to acidification, and acidification in the presence of salts, before DNA binding. Results show that although these pre-treatments did not affect the ability of particles to bind DNA they did significantly enhanced transfection efficiency. Finally, we show that these magnetofectins (PEI-MNP/DNA) complexes have no effect on the viability of cells at the concentrations used in the study. The systematic preparation of magnetic vectors with uniform physical and magnetic properties is critical to progressing this non-viral transfection technology.

  13. Helium, Iron and Electron Particle Transport and Energy Transport Studies on the TFTR Tokamak

    Science.gov (United States)

    Synakowski, E. J.; Efthimion, P. C.; Rewoldt, G.; Stratton, B. C.; Tang, W. M.; Grek, B.; Hill, K. W.; Hulse, R. A.; Johnson, D .W.; Mansfield, D. K.; McCune, D.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Redi, M. H.; Scott, S. D.; Taylor, G.; Timberlake, J.; Zarnstorff, M. C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Kissick, M. W. (Wisconsin Univ., Madison, WI (United States))

    1993-03-01

    Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

  14. Magnetic manipulation of actin orientation, polymerization, and gliding on myosin using superparamagnetic iron oxide particles

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yun; Guzik, Stephanie; Sumner, James P; Koretsky, Alan P [National Institutes of Health, Bethesda, MD (United States); Moreland, John, E-mail: koretskya@ninds.nih.gov [National Institute of Standards and Technology, Boulder, CO (United States)

    2011-02-11

    The actin cytoskeleton controls cell shape, motility, as well as intracellular molecular trafficking. The ability to remotely manipulate actin is therefore highly desirable as a tool to probe and manipulate biological processes at the molecular level. We demonstrate actin manipulation by labeling actin filaments with superparamagnetic iron oxide particles (IOPs) and applying a uniform magnetic field to affect actin orientation, polymerization and gliding on myosin. We show for the first time magnetic manipulation of magnetizable actin filaments at the molecular level while gliding on a bed of myosin molecules and during polymerization. A model for the magnetic alignment and guiding mechanism is proposed based on the torque from the induced molecular anisotropy due to interactions between neighboring IOPs distributed along magnetically labeled actin molecules.

  15. Visualization of antigen-specific human cytotoxic T lymphocytes labeled with superparamagnetic iron-oxide particles

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Ambros J. [Technical University of Munich (TUM), Department of Nuclear Medicine, Klinikum rechts der Isar, Munich (Germany); Holzapfel, Konstantin; Settles, Marcus; Rummeny, Ernst J. [Technical University of Munich, Department of Radiology, Klinikum rechts der Isar, Munich (Germany); Neudorfer, Juliana; Kroenig, Holger; Peschel, Christian; Bernhard, Helga [TUM, Munich, Department of Hematology/Oncology, Klinikum rechts der Isar, Munich (Germany); Piontek, Guido; Schlegel, Juergen [TUM, Munich, Division of Neuropathology, Institute of Pathology, Klinikum rechts der Isar, Munich (Germany)

    2008-06-15

    New technologies are needed to characterize the migration and survival of antigen-specific T cells in vivo. In this study, we developed a novel technique for the labeling of human cytotoxic T lymphocytes with superparamagnetic iron-oxide particles and the subsequent depiction with a conventional 1.5-T magnetic resonance scanner. Antigen-specific CD8{sup +} T lymphocytes were labeled with ferucarbotran by lipofection. The uptake of ferucarbotran was confirmed by immunofluorescence microscopy using a dextran-specific antibody, and the intracellular enrichment of iron was measured by atomic absorption spectrometry. The imaging of T cells was performed by magnetic resonance on day 0, 2, 7 and 14 after the labeling procedure. On day 0 and 2 post labeling, a pronounced shortening of T2*-relaxation times was observed, which diminished after 7 days and was not detectable anymore after 14 days, probably due to the retained mitotic activity of the labeled T cells. Of importance, the antigen-specific cytolytic activity of the T cells was preserved following ferucarbotran labeling. Efficient ferucarbotran labeling of functionally active T lymphocytes and their detection by magnetic resonance imaging allows the in vivo monitoring of T cells and, subsequently, will impact the further development of T cell-based therapies. (orig.)

  16. Particles that slide over the water surface: Synthesis and characterization of iron oxides particles coated with PDMS, with hydrophobic and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Souza Neto, Francisco N.de [Sciences and Technology Unit of the University – UnUCET, State University of Goiás, 75132-903 Anápolis, GO (Brazil); Araújo, Olacir Alves, E-mail: olacir.araujo@ueg.br [Sciences and Technology Unit of the University – UnUCET, State University of Goiás, 75132-903 Anápolis, GO (Brazil); Guilherme, Luciana R.; Garg, Vijayendra K. [Sciences and Technology Unit of the University – UnUCET, State University of Goiás, 75132-903 Anápolis, GO (Brazil); Oliveira, Aderbal C.; Souza, Paulo E.N. de [Institute of Physics, University of Brasília, 70910-900 Brasília, DF (Brazil); Franco Júnior, Adolfo [Institute of Physics, Federal University of Goiás, 74001-970 Goiânia, GO (Brazil)

    2015-07-15

    Magnetic nanoparticles have been of great scientific interest because of their possible industrial and biomedical applications. The magnetic iron oxide was synthesized by the co precipitation of alkaline hydrolysis of ions Fe{sup 2+} and Fe{sup 3+} in aqueous system. The coated particles were obtained by heating (50 and 250 °C) mixed magnetic iron oxide and polydimethylsiloxane oil for 30 min obtaining magnetic dust particles with hydrophobic behavior. These were used to learn the dragging effects and removal of nonpolar organic compound in aqueous systems. The samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), chemical analysis by potenciometric titration, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), contact angle measurement and Mössbauer spectroscopy. The diffractogram of X-ray presented peaks that were assigned to presence of spinel structure maghemite and magnetite with medium sized crystallites of 10.95 nm for the polymeric coated magnetic iron oxide, confirmed by TEM, with superparamagnetic character, also confirmed by VSM. The infrared spectrum showed absorption band at 570 cm{sup −1} characteristic of the Fe-O bonding in inverted spinel structure and the absorption bands in 1263, 1105, 1025 and 800 cm{sup −1} indicating the presence of PDMS on the magnetic iron oxide particles. Thermogravimetric analysis has been used to estimate the sample thermal stability of polymeric material (9.7 ± 4) % on the inorganic matrices. Contact angle measurement of the coated samples at 250 °C presented a better nonpolar character in comparison to the coated samples at 50 °C. The samples at room temperature (25 °C) presented the phases of magnetite and maghemite which were also confirmed by Mössbauer spectroscopy. It was possible to obtain iron oxides particles coated with PDMS, with hydrophobic and magnetic properties, which slide over the

  17. Immunohistochemical evidence of rapid extracellular matrix remodeling after iron-particle irradiation of mouse mammary gland

    Science.gov (United States)

    Ehrhart, E. J.; Gillette, E. L.; Barcellos-Hoff, M. H.; Chaterjee, A. (Principal Investigator)

    1996-01-01

    High-LET radiation has unique physical and biological properties compared to sparsely ionizing radiation. Recent studies demonstrate that sparsely ionizing radiation rapidly alters the pattern of extracellular matrix expression in several tissues, but little is known about the effect of heavy-ion radiation. This study investigates densely ionizing radiation-induced changes in extracellular matrix localization in the mammary glands of adult female BALB/c mice after whole-body irradiation with 0.8 Gy 600 MeV iron particles. The basement membrane and interstitial extracellular matrix proteins of the mammary gland stroma were mapped with respect to time postirradiation using immunofluorescence. Collagen III was induced in the adipose stroma within 1 day, continued to increase through day 9 and was resolved by day 14. Immunoreactive tenascin was induced in the epithelium by day 1, was evident at the epithelial-stromal interface by day 5-9 and persisted as a condensed layer beneath the basement membrane through day 14. These findings parallel similar changes induced by gamma irradiation but demonstrate different onset and chronicity. In contrast, the integrity of epithelial basement membrane, which was unaffected by sparsely ionizing radiation, was disrupted by iron-particle irradiation. Laminin immunoreactivity was mildly irregular at 1 h postirradiation and showed discontinuities and thickening from days 1 to 9. Continuity was restored by day 14. Thus high-LET radiation, like sparsely ionizing radiation, induces rapid-remodeling of the stromal extracellular matrix but also appears to alter the integrity of the epithelial basement membrane, which is an important regulator of epithelial cell proliferation and differentiation.

  18. Rapid removal of chloroform, carbon tetrachloride and trichloroethylene in water by aluminum-iron alloy particles.

    Science.gov (United States)

    Xu, Jie; Pu, Yuan; Yang, Xiao Jin; Wan, Pingyu; Wang, Rong; Song, Peng; Fisher, Adrian

    2017-09-05

    Water contamination with chlorinated hydrocarbons such as chloroform (CHCl3), carbon tetrachloride (CCl4) and trichloroethylene (TCE) is one of the major public health concerns. In this study, we explored the use of aluminum-iron alloys particles in millimeter scale for rapid removal of CHCl3, CCl4 and TCE from water. Three types of Al-Fe alloy particles containing 10, 20 and 58 wt% of Fe (termed as Al-Fe10, Al-Fe20 and Al-Fe58) were prepared and characterized by electrochemical polarization, X-ray diffraction and energy dispersive spectrometer. For concentrations of 30-180 μg/L CHCl3, CCl4 and TCE, a removal efficiency of 45-64% was achieved in a hydraulic contact time of less than 3 min through a column packed with 0.8-2 mm diameter of Al-Fe alloy particles. The concentration of Al and Fe ions released into water was less than 0.15 and 0.05 mg/L, respectively. Alloying Al with Fe enhances reactivity towards chlorinated hydrocarbons' degradation and the enhancement is likely the consequence of galvanic effects between different phases (Al, Fe and intermetallic Al-Fe compounds such as Al13Fe4, Fe3Al and FeAl2) and catalytic role of these intermetallic Al-Fe compounds. The results demonstrate that the use of Al-Fe alloy particles offers a viable and green option for chlorinated hydrocarbons' removal in water treatment.

  19. Iron metabolism in Rhodobacter capsulatus. Characterisation of bacterioferritin and formation of non-haem iron particles in intact cells.

    Science.gov (United States)

    Ringeling, P L; Davy, S L; Monkara, F A; Hunt, C; Dickson, D P; McEwan, A G; Moore, G R

    1994-08-01

    The water-soluble cytochrome b557 from the photosynthetic bacterium Rhodobacter capsulatus was purified and shown to have the properties of the iron-storage protein bacterioferritin. The molecular mass of R. capsulatus bacterioferritin is 428 kDa and it is composed of a single type of 18-kDa subunit. The N-terminal amino acid sequence of the bacterioferritin subunit shows 70% identity to the sequence of bacterioferritin subunits from Escherichia coli, Nitrobacter winogradskyi, Azotobacter vinelandii and Synechocystis PCC 6803. The absorbance spectrum of reduced bacterioferritin shows absorbance maxima at 557 nm (alpha band), 526 nm (beta band) and 417 nm (Soret band) from the six haem groups/molecule. Antibody assays reveal that bacterioferritin is located in the cytoplasm of R. capsulatus, and its levels stay relatively constant during batch growth under aerobic conditions when the iron concentration in the medium is kept constant. Iron deficiency leads to a decrease in bacterioferritin and iron overload leads to an increase. Bacterioferritin from R. capsulatus has an amorphous iron-oxide core with a high phosphate content (900-1000 Fe atoms and approximately 600 phosphates/bacterioferritin molecule). Mössbauer spectroscopy indicates that in both aerobically and anaerobically (phototrophically) grown cells bacterioferritin with an Fe3+ core is formed, suggesting that iron-core formation in vivo may not always require molecular oxygen.

  20. Influence of composition of carbonyl iron particles on dynamic mechanical properties of magnetorheological elastomers

    Science.gov (United States)

    Yu, Miao; Ju, Benxiang; Fu, Jie; Liu, Xueqin; Yang, Qi

    2012-07-01

    Magnetorheological elastomers (MRE) are known as smart materials. However, the magnetorheological (MR) effect of MRE is not high enough at present, which limits its engineering applications. Prior studies have shown that magneto-induced shear storage modulus and MR effect were mainly determined by the performance of the ferromagnetic particles. In this paper, MRE samples were prepared by carbonyl iron particles (CIP) of different compositions based on silicon rubber under external magnetic field. Their microstructures were observed using an optical digital microscope and a scanning electron microscope. The dynamic mechanical properties of MRE samples were measured using a modified dynamic mechanical analyzer under varying magnetic field strength and frequency. The results show that the carbon content of CIP have a greater impact on the dynamic mechanical properties of MRE. The magneto-induced shear storage modulus and MR effect can be increased by selecting CIP of low carbon content. In addition, the damping property is also significantly influenced by the carbon content of the CIP. This study is expected to provide guidance for fabrication of high performance MRE.

  1. The Role and Potential Dangers of Visualisation When Learning about Sub-Microscopic Explanations in Chemistry Education

    Science.gov (United States)

    Eilks, Ingo; Witteck, Torsten; Pietzner, Verena

    2012-01-01

    The core of theory-driven chemistry education consists of the constant shift between the different representational domains of chemical thinking: the macroscopic, the sub-microscopic, and the symbolic domains. Because the sub-microscopic domain can neither be seen nor directly visualised, it requires specific forms of visualisation, i.e. pictures…

  2. Removal of iron oxide particles in a gas stream by means of a magnetically stabilized granular filter

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.M.; Macias-Machin, A. [ETSII de Las Palmas (Spain); Alvaro, A.; Sanchez, J.R.; Estevez, A.M. [Univ. de Salamanca (Spain). Dept. de Ingenieria Quimica y Textil

    1999-01-01

    The present study deals with the influence of diverse operating variables such as gas velocity, height of the bed, magnetic field strength, and particle bounce on separation of fine dust particles (iron oxide) in magnetically stabilized granular filters (MSF). The collection results are more effective when the height of the MSF and dust sizes increase. Investigations concerning the magnetic field behavior have shown that the collection efficiency increases when the magnetic field also increases. And the increase of the magnetic field strength has shown that particle bounce significantly decreases and the adhesion probability of the MSF improves.

  3. Microwave absorbing property of silicone rubber composites with added carbonyl iron particles and graphite platelet

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang; Zhang, Deyuan [Bionic and Micro/Nano/Bio-Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Cai, Jun, E-mail: jun_cai@buaa.edu.cn [Bionic and Micro/Nano/Bio-Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Yuan, Liming; Zhang, Wenqiang [Bionic and Micro/Nano/Bio-Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2013-02-15

    Silicone rubber composites filled with carbonyl iron particles (CIPs) and graphite platelet (GP) were prepared using non-coating or coating processes. The complex permittivity and permeability of the composites were measured using a vector network analyzer in the frequency range of 1-18 GHz and dc electric conductivity was measured by the standard four-point contact method. The results showed that CIPs/GP composites fabricated in the coating process had the highest permittivity and permeability due to the particle orientation and interactions between the two absorbents. The coating process resulted in a decreased effective eccentricity of the absorbents, and the dc conductivity increased according to Neelakanta's equations. The reflection loss (RL) value showed that the composites had an excellent absorbing property in the L-band, minimum -11.85 dB at 1.5 mm and -15.02 dB at 2 mm. Thus, GP could be an effective additive in preparing thin absorbing composites in the L-band. - Highlights: Black-Right-Pointing-Pointer The added GP increased the permittivity and permeability of composites filled with CIPs. Black-Right-Pointing-Pointer The enhancement was owing to interactions of the two absorbents and the fabrication process. Black-Right-Pointing-Pointer The coating process decreased the effective eccentricity of the particles, and increased the conductivity of the composites. Black-Right-Pointing-Pointer The composites to which CIPs/GP were added in coating process had excellent absorbing properties in the L-band.

  4. Effects of magnetic field strength and particle aggregation on relaxivity of ultra-small dual contrast iron oxide nanoparticles

    Science.gov (United States)

    Ta, Hang T.; Li, Zhen; Wu, Yuao; Cowin, Gary; Zhang, Shaohua; Yago, Anya; Whittaker, Andrew K.; Xu, Zhi Ping

    2017-11-01

    This study aims to compare the relaxivities of ultra-small dual positive and negative contrast iron oxide nanoparticles (DCION) at different magnetic field strengths ranging from 4.7 to 16.4 T at physiological temperatures; and to investigate the effect of particle aggregation on relaxivities. Relaxivities of DCIONs were determined by magnetic resonance imaging scanners at 4.7, 7, 9.4, and 16.4 T. Both longitudinal (T 1) and transverse relaxation times (T 2) were measured by appropriate spin-echo sequences. It has been found that both longitudinal and transverse relaxivities are significantly dependent on the magnetic field strength. Particle aggregation also strongly affects the relaxivities. Awareness of the field strength and particle colloid stability is crucial for the comparison and evaluation of relaxivity values of these ultra-small iron oxide nanoparticles, and also for their medical applications as contrast agents.

  5. High sensitivity tracer imaging of iron oxides using magnetic particle imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodwill, Patrick [University of California, Dept. of Bioengineering, Berkeley, CA (United States); Konkle, Justin; Lu, Kuan; Zheng, Bo [UC Berkeley (UCSF), Joint Graduate Group in Bioengineering, CA (United States); Conolly, Steven [University of California, Berkeley Bioengineering, Electrical Engineering, and Computer Science, CA (United States)

    2014-07-01

    Full text: Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the 'black blood' contrast generated by SPIOs in MRI due to increased T2 dephasing, SPIOs in MPI generate positive, 'bright blood' contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. (author)

  6. Iron oxide nanoparticle-micelles (ION-micelles for sensitive (molecular magnetic particle imaging and magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Lucas W E Starmans

    Full Text Available BACKGROUND: Iron oxide nanoparticles (IONs are a promising nanoplatform for contrast-enhanced MRI. Recently, magnetic particle imaging (MPI was introduced as a new imaging modality, which is able to directly visualize magnetic particles and could serve as a more sensitive and quantitative alternative to MRI. However, MPI requires magnetic particles with specific magnetic properties for optimal use. Current commercially available iron oxide formulations perform suboptimal in MPI, which is triggering research into optimized synthesis strategies. Most synthesis procedures aim at size control of iron oxide nanoparticles rather than control over the magnetic properties. In this study, we report on the synthesis, characterization and application of a novel ION platform for sensitive MPI and MRI. METHODS AND RESULTS: IONs were synthesized using a thermal-decomposition method and subsequently phase-transferred by encapsulation into lipidic micelles (ION-Micelles. Next, the material and magnetic properties of the ION-Micelles were analyzed. Most notably, vibrating sample magnetometry measurements showed that the effective magnetic core size of the IONs is 16 nm. In addition, magnetic particle spectrometry (MPS measurements were performed. MPS is essentially zero-dimensional MPI and therefore allows to probe the potential of iron oxide formulations for MPI. ION-Micelles induced up to 200 times higher signal in MPS measurements than commercially available iron oxide formulations (Endorem, Resovist and Sinerem and thus likely allow for significantly more sensitive MPI. In addition, the potential of the ION-Micelle platform for molecular MPI and MRI was showcased by MPS and MRI measurements of fibrin-binding peptide functionalized ION-Micelles (FibPep-ION-Micelles bound to blood clots. CONCLUSIONS: The presented data underlines the potential of the ION-Micelle nanoplatform for sensitive (molecular MPI and warrants further investigation of the Fib

  7. Concentration of lead, cadmium, and iron in sediment dust and total suspended particles before and after initialisation of integral production in iron and steel work plant Zenica.

    Science.gov (United States)

    Prcanović, Halim; Duraković, Mirnes; Beganović, Sanela

    2012-06-01

    Poor air quality is a common fact for all areas with base industry. The city of Zenica was once the metallurgical centre of Ex-Yugoslavia and is therefore highly polluted at present. Air pollution peaked in 1987 when average concentration of pollutants was extremely high (daily average concentration of SO(2) was 1800 μg m(-3)). With the beginning of the war in 1992, integral production in the steel work plant was shut down, to be re-launched in 2008. Limit values for iron do not exist, but iron has been monitored in Zenica for the past 28 years because of the presence of steel works. Concentrations of cadmium and lead have also been measured because they are very much present in polluted areas with steel works. The concentration of mentioned elements in air deposit and total suspended particles before and after integral production in the steel work plant was re-launched is the subject of this paper. Total suspended particles were measured in two locations using German standard VDI 2463 Blatt 4. Sediment dust was measured in nine locations using Bergerhoff method. The concentration of iron, lead, and cadmium was performed in the chemical laboratory of the Metallurgical Institute "Kemal Kapetanović" Zenica using standard methods. Higher concentrations of these parameters during the period of integral production clearly point to the impact of steel works on Zenica valley.

  8. THE EFFECT OF ORTHO- AND POLYPHOSPHATE ON THE PROPERTIES OF IRON PARTICLES AND SUSPENSIONS

    Science.gov (United States)

    Orthophosphate and polyphosphates are used widely by drinking water utilities to reduce lead, copper and iron release from distribution system materials, and reduce visible iron precipitation and related discolored-water complaints. Bench-scale experiments were conducted to evalu...

  9. Soluble Iron in Alveolar Macrophages Modulates Iron Oxide Particle-Induced Inflammatory Response via Prostaglandin E2 Synthesis

    Science.gov (United States)

    Ambient particulate matter (PM)-associated metals have been shown to play an important role in cardiopulmonary health outcomes. To study the modulation of inflammation by PM-associated soluble metal, we investigated intracellular solubility of radiolabelled iron oxide (59

  10. Effect of iron particle size and volume fraction on the magnetic properties of Fe/silicate glass soft magnetic composites

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wei; Jiang, Longtao; Liao, Yaqin; Song, Jiabin; Li, Bingqing; Wu, Gaohui, E-mail: dingweihit@163.com

    2015-03-15

    Fe/silicate glass soft magnetic composites (SMC) were fabricated by powder metallurgy with 1000 MPa pressure at room temperature, and then annealed at 700 °C for 90 min. The iron particles distributed uniformly in the composites, and have been separated from each other by a continuous silicate glass insulating layer. Fe/glass interface was well bonded and a quasi-continuous layer Fe{sub 3}O{sub 4} and FeO exited. Very fine crystalline phases Na{sub 12}Ca{sub 3}Fe{sub 2}(Si{sub 6}O{sub 18}){sub 2} were formed in silicate glass. Composite containing 57 vol% 75 μm iron particles demonstrated highest resistivity of 7.8×10{sup −3} Ω m. The μ{sub m}, B{sub s} and B{sub t} increased while H{sub c} of Fe/silicate glass composites decreased with the increase of average size of iron particles. The composite with highest amount (82 vol%) and largest average size (140 μm) of iron particles demonstrated best μ{sub m}, B{sub s} and B{sub t} and H{sub c}, which were 622, 1.57 T, 1.43 T, 278 A/m, respectively. The composite containing 57 vol% 75 μm iron particles demonstrated minimum core loss of 3.5 W/kg at 50 Hz and 28.1 W/kg at 400 Hz, while the composite containing 82 vol% 140 μm iron particles exhibited maximum core loss of 5.2 W/kg at 50 Hz and 67.7 W/kg at 400 Hz. - Highlights: • A new soft magnetic composite (SMC) material design scheme was put forward, for increasing annealing temperature and reducing thermal mismatch stress. • SMC with silicate glass insulation layers was prepared based on our design scheme. • Comparing with other SMCs, annealing temperature was higher, holding time was longer (700 °C for 90 min). • The composite has higher performance than conventional composite. Its relative permeability μ{sub m}, B{sub s} and B{sub r} and H{sub c} were 622, 1.57 T, 1.43 T, 278 A/m, respectively.

  11. Kinetics and thermodynamics of cadmium ion removal by adsorption onto nano zerovalent iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Boparai, Hardiljeet K., E-mail: hboparai@uwo.ca [Department of Civil and Environmental Engineering, Faculty of Engineering, University of Western Ontario, 1151 Richmond St. N, London, Ontario N6A 5B9 (Canada); Joseph, Meera; O' Carroll, Denis M. [Department of Civil and Environmental Engineering, Faculty of Engineering, University of Western Ontario, 1151 Richmond St. N, London, Ontario N6A 5B9 (Canada)

    2011-02-15

    Nano zerovalent iron (nZVI) is an effective adsorbent for removing various organic and inorganic contaminants. In this study, nZVI particles were used to investigate the removal of Cd{sup 2+} in the concentration range of 25-450 mg L{sup -1}. The effect of temperature on kinetics and equilibrium of cadmium sorption on nZVI particles was thoroughly examined. Consistent with an endothermic reaction, an increase in the temperature resulted in increasing cadmium adsorption rate. The adsorption kinetics well fitted using a pseudo second-order kinetic model. The calculated activation energy for adsorption was 54.8 kJ mol{sup -1}, indicating the adsorption process to be chemisorption. The intraparticle diffusion model described that the intraparticle diffusion was not the only rate-limiting step. The adsorption isotherm data could be well described by the Langmuir as well as Temkin equations. The maximum adsorption capacity of nZVI for Cd{sup 2+} was found to be 769.2 mg g{sup -1} at 297 K. Thermodynamic parameters (i.e., change in the free energy ({Delta}G{sup o}), the enthalpy ({Delta}H{sup o}), and the entropy ({Delta}S{sup o})) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. EDX analysis indicated the presence of cadmium ions on the nZVI surface. These results suggest that nZVI could be employed as an efficient adsorbent for the removal of cadmium from contaminated water sources.

  12. Kinetics and thermodynamics of cadmium ion removal by adsorption onto nano zerovalent iron particles.

    Science.gov (United States)

    Boparai, Hardiljeet K; Joseph, Meera; O'Carroll, Denis M

    2011-02-15

    Nano zerovalent iron (nZVI) is an effective adsorbent for removing various organic and inorganic contaminants. In this study, nZVI particles were used to investigate the removal of Cd(2+) in the concentration range of 25-450 mg L(-1). The effect of temperature on kinetics and equilibrium of cadmium sorption on nZVI particles was thoroughly examined. Consistent with an endothermic reaction, an increase in the temperature resulted in increasing cadmium adsorption rate. The adsorption kinetics well fitted using a pseudo second-order kinetic model. The calculated activation energy for adsorption was 54.8 kJ mol(-1), indicating the adsorption process to be chemisorption. The intraparticle diffusion model described that the intraparticle diffusion was not the only rate-limiting step. The adsorption isotherm data could be well described by the Langmuir as well as Temkin equations. The maximum adsorption capacity of nZVI for Cd(2+) was found to be 769.2 mg g(-1) at 297 K. Thermodynamic parameters (i.e., change in the free energy (ΔG(o)), the enthalpy (ΔH(o)), and the entropy (ΔS(o))) were also evaluated. The overall adsorption process was endothermic and spontaneous in nature. EDX analysis indicated the presence of cadmium ions on the nZVI surface. These results suggest that nZVI could be employed as an efficient adsorbent for the removal of cadmium from contaminated water sources. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. Ultra-small particles of iron oxide as peroxidase for immunohistochemical detection

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yihang; Song Mengjie; Zhang Xiaoqing; Zhang Yu; Wang Chunyu; Gu Ning [Jiangsu Key Laboratory for Biomaterials and Devices, State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096 (China); Xin Zhuang; Li Suyi, E-mail: zhangyu@seu.edu.cn, E-mail: guning@seu.edu.cn [Zhongda Hospital, Southeast University, Nanjing 210096 (China)

    2011-06-03

    Dimercaptosuccinic acid (DMSA) modified ultra-small particles of iron oxide (USPIO) were synthesized through a two-step process. The first step: oleic acid (OA) capped Fe{sub 3}O{sub 4} (OA-USPIO) were synthesized by a novel oxidation coprecipitation method in H{sub 2}O/DMSO mixing system, where DMSO acts as an oxidant simultaneously. The second step: OA was replaced by DMSA to obtain water-soluble nanoparticles. The as-synthesized nanoparticles were characterized by TEM, FTIR, TGA, VSM, DLS, EDS and UV-vis. Hydrodynamic sizes and Peroxidase-like catalytic activity of the nanoparticles were investigated. The hydrodynamic sizes of the nanoparticles (around 24.4 nm) were well suited to developing stable nanoprobes for bio-detection. The kinetic studies were performed to quantitatively evaluate the catalytic ability of the peroxidase-like nanoparticles. The calculated kinetic parameters indicated that the DMSA-USPIO possesses high catalytic activity. Based on the high activity, immunohistochemical experiments were established: using low-cost nanoparticles as the enzyme instead of expensive HRP, Nimotuzumab was conjugated onto the surface of the nanoparticles to construct a kind of ultra-small nanoprobe which was employed to detect epidermal growth factor receptor (EGFR) over-expressed on the membrane of esophageal cancer cell. The proper sizes of the probes and the result of membranous immunohistochemical staining suggest that the probes can be served as a useful diagnostic reagent for bio-detection.

  14. Students' Mind Wandering in Macroscopic and Submicroscopic Textual Narrations and Its Relationship with Their Reading Comprehension

    Science.gov (United States)

    Al-Balushi, Sulaiman M.; Al-Harthy, Ibrahim S.

    2015-01-01

    The aim of the current study was to investigate students' mind wandering while reading different types of textual narrations (macroscopic and submicroscopic) in chemistry. Another goal was to determine the relationship between mind wandering and students' reading comprehension. The participants were 65 female ninth grade students in Oman. Using a…

  15. Polymers and Cross-Linking: A CORE Experiment to Help Students Think on the Submicroscopic Level

    Science.gov (United States)

    Bruce, Mitchell R. M.; Bruce, Alice E.; Avargil, Shirly; Amar, Francois G.; Wemyss, Thomas M.; Flood, Virginia J.

    2016-01-01

    The Polymers and Cross-Linking experiment is presented via a new three phase learning cycle: CORE (Chemical Observations, Representations, Experimentation), which is designed to model productive chemical inquiry and to promote a deeper understanding about the chemistry operating at the submicroscopic level. The experiment is built on two familiar…

  16. Two-step milling on the carbonyl iron particles and optimizing on the composite absorption

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai 200438 (China); Yuan, Liming; Wang, Xiaobing [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai 200438 (China); Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2016-08-15

    The flaky carbonyl iron particles (CIPs) were prepared using a two-step milling process. The surface morphology was characterized by the scanning electron microscopy, the static magnetic property was evaluated on a vibrating sample magnetometer and X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2–18 GHz. Then Hermite interpolation based on the calculated scattering parameters of the tested composite was used to derive the permittivity and permeability of the composite with random volume content. The results showed that the saturation magnetization value of the flaky CIPs decreased as the CIPs was changed to the flakes by high and low speeding milling. The diffraction peaks of the single α-Fe existed in the XRD pattern of CIPs, and the characteristic peaks was broad and the intensity of the diffraction pattern was lower as the high-speeding milling time increased. The sample H2L20 had the largest particle size, the average diameter was 8.64 μm, the thickness was 0.59 μm according to the fitted aspect ratio 14.65. The derived permittivity and permeability using the Hermite interpolation was accurate compared with the tested result, the deviation was about 0.39 + j0.45 and 2.5 + j0.51. Finally, the genetic algorithm was used to optimize the thickness of the CIPs composite of a wide absorbing band of 8–18 GHz. The optimized reflection loss (RL) result showed that the absorbing composites with thickness 1.47 mm had an excellent absorbing property (RL < −10 dB) in 8–18 GHz. - Graphical abstract: The property of absorber added two speeding milling CIPs could be enhanced using the genetic algorithm. - Highlights: • Flaky CIPs were prepared using a two-step milling process. • The permeability increased during the low speeding milling. • The aspect ratio of flaky CIPs increased in the optimized process

  17. The removal of uranium onto carbon-supported nanoscale zero-valent iron particles.

    Science.gov (United States)

    Crane, Richard A; Scott, Thomas

    2014-01-01

    In the current work carbon-supported nanoscale zero-valent iron particles (CS nZVI), synthesised by the vacuum heat treatment of ferric citrate trihydrate absorbed onto carbon black, have been tested for the removal of uranium (U) from natural and synthetic waters. Two types of CS nZVI were tested, one vacuum annealed at 600 °C for 4 h and the other vacuum annealed at 700 °C for 4 h, with their U removal behaviour compared to nZVI synthesised via the reduction of ferrous iron using sodium borohydride. The batch systems were analysed over a 28-day reaction period during which the liquid and nanoparticulate solids were periodically analysed to determine chemical evolution of the solutions and particulates. Results demonstrate a well-defined difference between the two types of CS nZVI, with greater U removal exhibited by the nanomaterial synthesised at 700 °C. The mechanism has been attributed to the CS nZVI synthesised at 700 °C exhibiting (i) a greater proportion of surface oxide Fe(2+) to Fe(3+) (0.34 compared to 0.28); (ii) a greater conversion of ferric citrate trihydrate [2Fe(C6H5O7)·H2O] to Fe(0); and (iii) a larger surface area (108.67 compared to 88.61 m(2) g(-1)). Lower maximum U uptake was recorded for both types of CS nZVI in comparison with the borohydride-reduced nZVI. A lower decrease in solution Eh and DO was also recorded, indicating that less chemical reduction of U was achieved by the CS nZVI. Despite this, lower U desorption in the latter stages of the experiment (>7 days) was recorded for the CS nZVI synthesised at 700 °C, indicating that carbon black in the CS nZVI is likely to have contributed towards U sorption and retention. Overall, it can be stated that the borohydride-reduced nZVI were significantly more effective than CS nZVI for U removal over relatively short timescales (e.g. <48 h), however, they were more susceptible to U desorption over extended time periods.

  18. A SYSTEMATIC APPROACH FOR THE SEPERATION OF IRON PARTICLES IN SOLUBLE STATE USING LEAF EXTRACT

    OpenAIRE

    G. K. Monica Nandini; M. Chris Sheba

    2017-01-01

    The discharge of waste water, which contains many minerals like iron, magnesium, zinc etc., from various foundries, steel, dyeing and chemical industries; and treatment plants have substantial effects on the environment and the agricultural lands. Among these metallic elements, iron nanoparticles (FeNPs) have promising advantage that can combat environmental pollution. The interest in nano scale zero-valent iron in environmental remediation is increasing due to the reactivity of nanoscale iro...

  19. Iron isotope composition of particles produced by UV-femtosecond laser ablation of natural oxides, sulfides, and carbonates.

    Science.gov (United States)

    d'Abzac, Francois-Xavier; Beard, Brian L; Czaja, Andrew D; Konishi, Hiromi; Schauer, James J; Johnson, Clark M

    2013-12-17

    The need for femtosecond laser ablation (fs-LA) systems coupled to MC-ICP-MS to accurately perform in situ stable isotope analyses remains an open question, because of the lack of knowledge concerning ablation-related isotopic fractionation in this regime. We report the first iron isotope analysis of size-resolved, laser-induced particles of natural magnetite, siderite, pyrrhotite, and pyrite, collected through cascade impaction, followed by analysis by solution nebulization MC-ICP-MS, as well as imaging using electron microscopy. Iron mass distributions are independent of mineralogy, and particle morphology includes both spheres and agglomerates for all ablated phases. X-ray spectroscopy shows elemental fractionation in siderite (C-rich agglomerates) and pyrrhotite/pyrite (S-rich spheres). We find an increase in (56)Fe/(54)Fe ratios of +2‰, +1.2‰, and +0.8‰ with increasing particle size for magnetite, siderite, and pyrrhotite, respectively. Fe isotope differences in size-sorted aerosols from pyrite ablation are not analytically resolvable. Experimental data are discussed using models of particles generation by Hergenröder and elemental/isotopic fractionation by Richter. We interpret the isotopic fractionation to be related to the iron condensation time scale, dependent on its saturation in the gas phase, as a function of mineral composition. Despite the isotopic variations across aerosol size fractions, total aerosol composition, as calculated from mass balance, confirms that fs-LA produces a stoichiometric sampling in terms of isotopic composition. Specifically, both elemental and isotopic fractionation are produced by particle generation processes and not by femtosecond laser-matter interactions. These results provide critical insights into the analytical requirements for laser-ablation-based stable isotope measurements of high-precision and accuracy in geological samples, including the importance of quantitative aerosol transport to the ICP.

  20. Humic Acid Adsorption Onto Iron Oxide Magnetic Nano Particles in Aquious Solution

    Directory of Open Access Journals (Sweden)

    Maryam Foroghi

    2013-12-01

    Full Text Available Background & Objectives: Humic Acid (HA compounds affects water quality, such as color, taste and odor. The compounds not only react with disinfectants to produce disinfection by-products (DBPs harmful to human health. Iron oxide magnetic nanoparticles (MNPs have a high adsorption capacity to adsorb to organic matter. In this study HA removal by IOMNPs was surveyed in aqueous solutions. Methods:  The effects of pH value, agitation rate, adsorbent dose, contact time and the adsorbate concentration on the adsorption efficiency were studied as critical parameters. In addition, effect of ionic strength on the adsorption process and effluent turbidity was surveyed. The MNPs was characterized by X-ray diffraction. Results: Results revealed that at HA concentration of 10 mg/L, pH 4.5, adsorbent dose of 2.7 g/l, agitation rate of 250 rpm and contact time of 90 min at presence of 0.1 M NaCl as an ionic strength agent, the HA removal reached to about 98%. Also, the turbidity of treated samples was increased with increasing of HA loading. On the other hand, increases of ionic strength resulting in increase of removal efficiency and decrees of effluent turbidity. Conclusion: With increasing HA concentration, adsorption capacity of MNPs was increased and HA removal efficiency was decreased. Increasing of ionic strength leads to increase of removal efficiency and decrease of nano particles release. MNPs are easily attracted to the magnetic field application leads to easy separation from aquatic environment.

  1. Improved rheological properties of dimorphic magnetorheological gels based on flower-like carbonyl iron particles

    Science.gov (United States)

    Yang, Pingan; Yu, Miao; Luo, Hongping; Fu, Jie; Qu, Hang; Xie, Yuanpeng

    2017-09-01

    In this study, a new kind of dimorphic magnetorheological gels (MRGs) based on the conventional carbonyl iron particles (CIPs) and flower-like CIPs have been prepared for improving the yield stress and dynamic mechanical properties. The flower-like CIPs are synthesized by a simple and facile in situ reduction method. Characterization results indicate that the flower-like CIPs are synthesized successfully and a layer of uniform and continuous Fe nanosheets are grown on the surface of the raw microsphere CIPs. In addition, the flower-like CIPs exhibit excellent magnetic properties, which the saturated mass magnetization (Ms) can achieve 168.76 emu/g. In order to study the influence of mass fraction of flower-like CIPs on the rheological properties of this dimorphic MRGs, a series of polyurethane-based dimorphic MRGs are prepared by partial substitution of the CIPs with as-synthesized flower-like CIPs, and the MR properties of them are systematically investigated under both oscillatory and rotational shear modes. The experimental results indicate that, with 8 wt% flower-like CIPs, the maximum dynamic yield stresses and magneto-induced shear yield stress of dimorphic MRGs are 58.11 kPa and 54.53 kPa, ∼1.39 and ∼1.37 times of the MRG without flower-like CIPs at the same magnetic particle content. Moreover, the average loss factor and the loss factor under 1 T of the sample (flower-like CIPs weight content 8 wt%) are 0.36 and 0.07, which are approximately 1.71 and 2.71 times than that in the non-substitution sample. The increased loss factor is beneficial to improving the vibration reduction effect of MRGs of damping devices in the whole magnetic field region. Furthermore, the possible mechanism for the enhanced MR properties in dimorphic MRGs is proposed. In summary, this work is expected to promote the design and application of MRG devices.

  2. Dispersion of iron oxide particles in industrial waters. The influence of polymer structure, ionic charge, and molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, Z. [Goodrich (B.F.) Co., Brecksville, OH (United States)

    1999-01-01

    This paper deals with studies on the influence of polymeric and non-polymeric materials on the dispersion of iron oxide particles in aqueous system. The aim of the work was to evaluate the performance of a variety of additives as iron oxide dispersants. The polymers investigated include homopolymers of acrylamide, vinylpyrrolidone, actylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, and acrylic acid based copolymers containing a variety of functional groups. It has been found that the addition of low levels of copolymers to the iron oxide suspension has a marked effect in dispersing iron oxide particles. The dispersancy data of several polymers indicate that the performance of the polymer depends upon the functional group, molecular weight, composition, and the ionic charge of the polymer. The results on non-polymeric materials such as polyphosphates, phosphonates, and surfactants show that these additives, compared to copolymers are ineffective as iron oxide dispersants. (orig.) [Deutsch] In dieser Arbeit wird der Einfluss von polymeren und nichtpolymeren Stoffen auf die Dispergierung von Eisenoxidpartikeln in waessrigen Systemen untersucht. Ziel dieser Arbeit war es, die Wirkung verschiedener Additive als Eisenoxiddispergatoren zu bewerten. Die untersuchten Polymere waren homopolymeres Acrylamid, Vinylpyrrolidon, Acrylsaeure, Maleinsaeure, 2-Acrylamido-2-Methylpropansulfonsaeure und Copolymere auf Acrylsaeurebasis mit verschiedenen fuktionellen Gruppen. Die Zugabe von geringen Mengen Copolymeren zur Eisenoxidsuspension hat einen deutlichen Einfluss auf die Dispergierung dieser Partikel. Die Daten zum Dispergierverhalten einiger Polymere zeigen, dass die Wirkung eines Polymers von der fuktionellen Gruppe, dem Molgewicht, der Zusammensetzung und der Ionenladung des Polymers abhaengt. Ergebnisse, die mit nichtpolymeren Substanzen wie Polyphosphaten, Phosphonaten und Tensiden erhalten wurden, zeigen, dass sich diese Additive nicht so gut als

  3. Toxicity of iron-based nanoparticles to green algae: Effects of particle size, crystal phase, oxidation state and environmental aging.

    Science.gov (United States)

    Lei, Cheng; Zhang, Luqing; Yang, Kun; Zhu, Lizhong; Lin, Daohui

    2016-11-01

    With the increasing environmental application and discharge of iron-based nanoparticles (NPs), a comprehensive understanding of their fate and ecotoxicological effect in the aquatic environment is very urgent. In this study, toxicities of 4 zero-valent iron NPs (nZVI) of different sizes, 2 Fe 2 O 3 NPs of different crystal phases, and 1 type of Fe 3 O 4 NPs to a green alga (Chlorella pyrenoidosa) were investigated, with a focus on the effects of particle size, crystal phase, oxidation state, and environmental aging. Results show that the algal growth inhibition of nZVI increased significantly with decreasing particle size; with similar particle sizes (20-30 nm), the algal growth inhibition decreased with oxidation of the NPs with an order of nZVI > Fe 3 O 4 NPs > Fe 2 O 3 NPs, and α-Fe 2 O 3 NPs presented significantly higher toxicity than γ-Fe 2 O 3 NPs. The NP-induced oxidative stress was the main toxic mechanism, which could explain the difference in algal toxicity of the NPs. The NP-cell heteroagglomeration and physical interactions also contributed to the nanotoxicity, whereas the effect of NP dissolution was negligible. The aging in distilled water and 3 surface water samples for 3 months increased surface oxidation of the iron-based NPs especially nZVI, which decreased the toxicity to algae. These findings will be helpful for the understanding of the fate and toxicity of iron-based NPs in the aquatic environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Synthesis and Characterization of Surface Grafted Poly(N-isopropylacrylamide) and Poly(Carboxylic Acid)- Iron Particles via Atom Transfer Radical Polymerization for Biomedical Applications.

    Science.gov (United States)

    Sutrisno, Joko; Fuchs, Alan; Evrensel, Cahit

    2014-07-15

    This research relates to the preparation and characterization of surface grafted poly(N-isopropylacrylamide) and poly(carboxylic acid)-micron-size iron particles via atom transfer radical polymerization (ATRP). The surface grafted polymers-iron particles result in multifunctional materials which can be used in biomedical applications. The functionalities consist of cell targeting, imaging, drug delivery, and immunological response. The multifunctional materials are synthesized in two steps. First, surface grafting is used to place polymer molecules on the iron particles surface. The second step, is conjugation of the bio-molecules onto the polymer backbone. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy were used to confirm the presence of polymers on the iron particles. The thickness of the grafted polymers and glass transition temperature of the surface grafted polymers were determined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The covalent bond between grafted polymers and iron particles caused higher glass transition temperature as compared with non-grafted polymers. The ability to target the bio-molecule and provide fluorescent imaging was simulated by conjugation of rat immunoglobulin and fluorescein isothiocyanate (FITC) labeled anti-rat. The fluorescence intensity was determined using flow cytometry and conjugated IgG-FITC anti-rat on iron particles which was imaged using a fluorescence microscopy.

  5. Synthesis and Characterization of Surface Grafted Poly(N-isopropylacrylamide) and Poly(Carboxylic Acid)– Iron Particles via Atom Transfer Radical Polymerization for Biomedical Applications

    Science.gov (United States)

    Sutrisno, Joko; Fuchs, Alan; Evrensel, Cahit

    2014-01-01

    This research relates to the preparation and characterization of surface grafted poly(N-isopropylacrylamide) and poly(carboxylic acid)–micron-size iron particles via atom transfer radical polymerization (ATRP). The surface grafted polymers–iron particles result in multifunctional materials which can be used in biomedical applications. The functionalities consist of cell targeting, imaging, drug delivery, and immunological response. The multifunctional materials are synthesized in two steps. First, surface grafting is used to place polymer molecules on the iron particles surface. The second step, is conjugation of the bio-molecules onto the polymer backbone. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy were used to confirm the presence of polymers on the iron particles. The thickness of the grafted polymers and glass transition temperature of the surface grafted polymers were determined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The covalent bond between grafted polymers and iron particles caused higher glass transition temperature as compared with non-grafted polymers. The ability to target the bio-molecule and provide fluorescent imaging was simulated by conjugation of rat immunoglobulin and fluorescein isothiocyanate (FITC) labeled anti-rat. The fluorescence intensity was determined using flow cytometry and conjugated IgG-FITC anti-rat on iron particles which was imaged using a fluorescence microscopy. PMID:25382869

  6. Effectiveness of micron-sized superparamagnetic iron oxide particles as markers for detection of migration of bone marrow-derived mesenchymal stromal cells in a stroke model.

    Science.gov (United States)

    Tarulli, Emidio; Chaudhuri, Joydeep D; Gretka, Voytek; Hoyles, Amy; Morshead, Cindi M; Stanisz, G J

    2013-06-01

    To evaluate the feasibility of using micron-sized superparamagnetic iron oxide particles (MPIOs) as an effective labeling agent for monitoring bone marrow-derived mesenchymal stromal cell (BMSC) migration in the brain using magnetic resonance imaging (MRI) in a rat model of stroke and whether the accumulation of MPIO-labeled BMSCs can be differentiated from the accumulation of free MPIO particles or hemoglobin breakdown at a site of neuronal damage. In this study BMSCs were labeled with iron oxide and their pattern of migration following intravenous injection in a rat stroke model was monitored using a clinical MRI system followed by standard histopathology. The migration pattern was compared between intravenous injection of BMSCs alone, BMSCs labeled with MPIOs, and MPIO particles alone. The results demonstrated that while MRI was highly sensitive in the detection of iron oxide particle-containing cells in areas of neuronal ischemia, the true origin of cells containing iron oxide particles remains ambiguous. Therefore, detection of iron particles may not be a suitable strategy for the detection of BMSCs in the brain in a stroke model. This study suggests that the use of MPIOs as labeling agents are insufficient to conclusively determine the localization of iron within cells in regions of neuronal ischemia and hemorrhage. Copyright © 2012 Wiley Periodicals, Inc.

  7. Flocculated meltwater particles control Arctic land-sea fluxes of labile iron

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Elberling, Bo; Winter, Christian

    2016-01-01

    Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our res...... the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters....

  8. Characterization of Iron-Oxide Loaded Adult Stem Cells for Magnetic Particle Imaging in Targeted Cancer Therapy

    Science.gov (United States)

    Lüdtke-Buzug, Kerstin; Rapoport, Daniel Hans; Schneider, Dagmar

    2010-12-01

    Recently, magnetic particle imaging (MPI) has been presented as a new method for the measurement of the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). MPI is based on the nonlinear magnetization response of nanoparticles that are subjected to a sinusoidal magnetic field. Spatial resolution and signal to noise ratio of MPI depend on the particle quality. This is particularly important when stem cells shall be tracked with MPI. Stem cell-based treatment is an upcoming technology in targeted cancer-therapy. In this study, we analyzed the particle quality of newly developed dextran-coated SPIONs—with respect to their response in the imaging experiment—using magnetic particle spectrometry. The uptake of dextran-coated SPIONs into rat and human adult stem cells was monitored via transmission electron microscopy. Furthermore, adult stem cells were incubated with FITC-dextran-coated SPIONs and stained for confocal laser scanning microscopy. The dextran- and FITC-dextran coated SPIONs were localized in the cytoplasm of rat and human adult stem cells. MPI promises real-time imaging with high spatial resolution at high sensitivity. Our data support iron oxide loaded adult stem cells as a powerful tool for targeted cancer therapy.

  9. Evidence for a ubiquitous, sub-microscopic 'magnetite-like' constituent in the lunar soils

    Science.gov (United States)

    Griscom, D. L.; Friebele, E. J.; Marquardt, C. L.

    1973-01-01

    Electron spin resonance (ESR) has been employed in a study of the ferromagnetic constituents of a wide variety of soils from six sampled regions of the moon as well as glasses made to simulate lunar compositions. A significant result has been that magnetite-like phases (magnetic iron spinel) precipitated in and on simulated lunar glasses as a result of sub-solidus oxidation yield room-temperature ESR spectra virtually identical with the line shape predicted for spherical, single domain particles of metallic Fe. It is shown that such magnetite-like phases can nevertheless be distinguished from metallic iron on the basis of the temperature dependence of the ESR intensity.

  10. Carbothermal synthesis of carbon-supported nanoscale zero-valent iron particles for the remediation of hexavalent chromium.

    Science.gov (United States)

    Hoch, Laura B; Mack, Elizabeth J; Hydutsky, Bianca W; Hershman, Jessica M; Skluzacek, Joanna M; Mallouk, Thomas E

    2008-04-01

    Nanoscale, zero-valent iron is a promising reagent for in situ reduction of a variety of subsurface contaminants, but its utility in full-scale remediation projects is limited by material costs. Iron nanoparticles (20-100 nm diameter) supported on carbon (C-Fe0) were synthesized by reacting iron salts, adsorbed or impregnated from aqueous solutions onto 80 m2/g carbon black, at 600-800 degrees C under Ar. Similar products were obtained by heating the reactants under air in a covered alumina crucible. X-ray powder diffraction patterns show that Fe3O4 particles are formed at 300-500 degrees C in the initial stage of the reaction and that these particles are reduced to a mixture of alpha- and gamma-Fe nanoparticles above 600 degrees C. When C-Fe0 was combined with carboxymethylcellulose in a 5:1 weight ratio in water, the resulting material had similar transport properties to previously optimized nanoiron/polyanion suspensions in water-saturated sand columns. At a 10:3 Fe/Cr mole ratio, C-Fe0 reduced a 10 ppm Cr(VI) solution to approximately 1 ppm within three days. The surface area normalized first-order Cr removal rate was 1.2 h(-1) m(-2) under these conditions. These results demonstrate that reactive nanoiron with good transport properties in water-saturated porous media can be made in a scalable process from inexpensive starting materials by carbothermal reduction.

  11. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

    2015-01-01

    fraction was found in the sample with occurrence of small nano-sized particles (b10 nm). The results show the importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. © 2015 Elsevier B.V. All......The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution......, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples N50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found...

  12. Electromagnetic, magnetorheological and stability properties of polysiloxane elastomers based on silane-modified carbonyl iron particles with enhanced wettability

    Science.gov (United States)

    Cvek, Martin; Moucka, Robert; Sedlacik, Michal; Pavlinek, Vladimir

    2017-10-01

    Soft carbonyl iron (CI) particles were successfully modified with a thin layer of tetraethoxysilane (TEOS) to enhance the wettability of their surface in hydrophobic media. The contact angle investigations and tensiometric analysis revealed and helped quantify the significantly enhanced wettability and, thus, the better interfacial adhesion of the TEOS-coated CI particles (CI-TEOS) with the non-polar siloxane-based materials. Therefore, stable magnetorheological elastomers (MREs) based on CI-TEOS particles and polydimethyl siloxane matrix were fabricated. The prepared composites had different particle loadings and microstructural characteristics: isotropic and anisotropic. These structural differences were confirmed by scanning electron microscopy and were found to considerably affect dielectric properties of the MREs due to various charge transport mechanisms within the particle clusters. Furthermore, the magnetorheological (MR) performances of isotropic MRE variants were analysed before and after exposure to acidic environment. After the corrosion test, the MRE based on bare CI particles exhibited dramatically decreased relative MR effect and mechanical properties when compared with its analogue containing CI-TEOS.

  13. Environmental application of millimeter-scale sponge iron (s-Fe{sup 0}) particles (II): The effect of surface copper

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming, E-mail: juyongming@scies.org [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Liu, Xiaowen, E-mail: liuxiaowen@scies.org [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Liu, Runlong; Li, Guohua; Wang, Xiaoyan; Yang, Yanyan; Wei, Dongyang; Fang, Jiande [South China Institute of Environmental Sciences, The Ministry of Environmental Protection of the PRC, Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, Ohio 45221-0012 (United States)

    2015-04-28

    Highlights: • Facile reduction reaction achieves decoration of Cu{sup 0} onto the surface of s-Fe{sup 0}. • The removal efficiency of RhB over Cu{sup 0}–s-Fe{sup 0} was similar to that of Cu{sup 0}–nZVI. • Cu{sup 0}–s-Fe{sup 0} can operate under mild condition with lower cost compared to nZVI. • The reductive mechanism over Cu{sup 0}–s-Fe{sup 0} under US condition is also elucidated. - Abstract: To enhance the catalytic reactivity of millimeter-scale particles of sponge iron (s-Fe{sup 0}), Cu{sup 2+} ions were deposited on the surface of s-Fe{sup 0} using a simple direct reduction reaction, and the catalytic properties of the bimetallic system was tested for removal of rhodamine B (RhB) from an aqueous solution. The influence of Cu{sup 0} loading, catalyst dosage, particle size, initial RhB concentration, and initial pH were investigated, and the recyclability of the catalyst was also assessed. The results demonstrate that the 3 ∼ 5 millimeter s-Fe{sup 0} particles (s-Fe{sup 0}(3 ∼ 5 mm)) with 5 wt% Cu loading gave the best results. The removal of RhB followed two-step, pseudo-first-order reaction kinetics. Cu{sup 0}–s-Fe{sup 0} showed excellent stability after five reuse cycles. Cu{sup 0}–s-Fe{sup 0} possesses great advantages compared to nanoscale zero-valent iron, iron power, and iron flakes as well as its bimetals. The surface Cu{sup 0} apparently catalyzes the production of reactive hydrogen atoms for indirect reaction and generates Fe-Cu galvanic cells that enhance electron transfer for direct reaction. This bimetallic catalyst shows great potential for the pre-treatment of recalcitrant wastewaters. Additionally, some oxides containing iron element are selected to simulate the adsorption process. The results prove that the adsorption process of FeOOH, Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} played minor role for the removal of RhB.

  14. Submicroscopic malaria parasite carriage: how reproducible are polymerase chain reaction-based methods?

    Directory of Open Access Journals (Sweden)

    Daniela Camargos Costa

    2014-02-01

    Full Text Available The polymerase chain reaction (PCR-based methods for the diagnosis of malaria infection are expected to accurately identify submicroscopic parasite carriers. Although a significant number of PCR protocols have been described, few studies have addressed the performance of PCR amplification in cases of field samples with submicroscopic malaria infection. Here, the reproducibility of two well-established PCR protocols (nested-PCR and real-time PCR for the Plasmodium 18 small subunit rRNA gene were evaluated in a panel of 34 blood field samples from individuals that are potential reservoirs of malaria infection, but were negative for malaria by optical microscopy. Regardless of the PCR protocol, a large variation between the PCR replicates was observed, leading to alternating positive and negative results in 38% (13 out of 34 of the samples. These findings were quite different from those obtained from the microscopy-positive patients or the unexposed individuals; the diagnosis of these individuals could be confirmed based on the high reproducibility and specificity of the PCR-based protocols. The limitation of PCR amplification was restricted to the field samples with very low levels of parasitaemia because titrations of the DNA templates were able to detect < 3 parasites/µL in the blood. In conclusion, conventional PCR protocols require careful interpretation in cases of submicroscopic malaria infection, as inconsistent and false-negative results can occur.

  15. The catalytic activity of the iron-coated pumice particles used as heterogeneous catalysts in the oxidation of natural organic matter by H2O2.

    Science.gov (United States)

    Alver, Alper; Karaarslan, Mihrican; Kılıç, Ahmet

    2016-08-01

    The oxidative removal of natural organic matter (NOM) from waters was investigated by hydrogen peroxide (H2O2) and iron-coated pumice particles in heterogeneous catalytic oxidation process (HCOP). Removal of trihalomethane (THM) precursors, which is formed THM by the reacts with chloride, was performed with the hydroxyl radicals. Coating the original pumice particles with iron oxides significantly enhanced the removal of NOM with peroxide. The studies were carried out in two sections: (1) decomposition of hydrogen peroxide in pure water with iron-coated pumice and (2) oxidation of THM Precursor (NOM) by hydrogen peroxide with iron-coated pumice. The monitored parameters in this study include dissolved organic carbon and trihalomethanes formation potential. The results show that iron-coated pumice catalyst significantly increased the removal efficiency of NOM in the HCOP. The results show that iron-coated pumice catalyst significantly increased the removal efficiency of NOM in the HCOP. Results show that the oxidation of NOM and remaining NOM with H2O2 is improved by the addition of iron-coated pumice particles which activate the H2O2 molecule, leading to the formation of hydroxyl radicals in a Fenton-like process.

  16. Antibiotic removal from water: Elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Ghauch, Antoine, E-mail: antoine.ghauch@aub.edu.l [American University of Beirut, Faculty of Arts and Sciences, Department of Chemistry, P.O. Box 11-0236, Riad El Solh, 1107-2020 Beirut (Lebanon); Tuqan, Almuthanna; Assi, Hala Abou [American University of Beirut, Faculty of Arts and Sciences, Department of Chemistry, P.O. Box 11-0236, Riad El Solh, 1107-2020 Beirut (Lebanon)

    2009-05-15

    Zerovalent iron powder (ZVI or Fe{sup 0}) and nanoparticulate ZVI (nZVI or nFe{sup 0}) are proposed as cost-effective materials for the removal of aqueous antibiotics. Results showed complete removal of Amoxicillin (AMX) and Ampicillin (AMP) upon contact with Fe{sup 0} and nFe{sup 0}. Antibiotics removal was attributed to three different mechanisms: (i) a rapid rupture of the beta-lactam ring (reduction), (ii) an adsorption of AMX and AMP onto iron corrosion products and (iii) sequestration of AMX and AMP in the matrix of precipitating iron hydroxides (co-precipitation with iron corrosion products). Kinetic studies demonstrated that AMP and AMX (20 mg L{sup -1}) undergo first-order decay with half-lives of about 60.3 +- 3.1 and 43.5 +- 2.1 min respectively after contact with ZVI under oxic conditions. In contrast, reactions under anoxic conditions demonstrated better degradation with t{sub 1/2} of about 11.5 +- 0.6 and 11.2 +- 0.6 min for AMP and AMX respectively. NaCl additions accelerated Fe{sup 0} consumption, shortening the service life of Fe{sup 0} treatment systems. - Fe{sup 0} is efficient for the aqueous removal of the beta-lactam antibiotics and chlorides enhanced the removal rate by sustaining the process of iron corrosion.

  17. Biosorbents prepared from wood particles treated with anionic polymer and iron salt: Effect of particle size on phosphate adsorption

    Science.gov (United States)

    Thomas L. Eberhardt; Soo-Hong Min

    2008-01-01

    Biomass-based adsorbents have been widely studied as a cost-effective and environmentally-benign means to remove pollutants and nutrients from water. A two-stage treatment of aspen wood particles with solutions of carboxymethyl cellulose (CMC) and ferrous chloride afforded a biosorbent that was effective in removing phosphate from test solutions. FTIR spectroscopy of...

  18. Students' Conceptions about the Sub-Microscopic Approach to ...

    African Journals Online (AJOL)

    NICO

    break when ice melts to form water? (a) O-H bonds. (b) O=O bonds. (c) H-H bonds. (d) Intermolecular bonds between H2O molecules. (e) Intramolecular bonds within the H2O molecules. Question 12. Give balanced chemical equations, using only the particles (i.e. atoms, ions, electrons, molecules) that are involved, for the.

  19. Chitosan-sodium alginate nanoparticles as submicroscopic reservoirs for ocular delivery: formulation, optimisation and in vitro characterisation.

    Science.gov (United States)

    Motwani, Sanjay K; Chopra, Shruti; Talegaonkar, Sushma; Kohli, Kanchan; Ahmad, Farhan J; Khar, Roop K

    2008-03-01

    Management of extraocular disease is mainly limited by the inability to provide long-term extraocular drug delivery without avoiding the systemic drug exposure and/or affecting the intraocular structures and poor availability of drugs, which may be overcome by prolonging the contact time with the ocular surface, for instance with bioadhesive polymers. In the present study, mucoadhesive chitosan (CS)-sodium alginate (ALG) nanoparticles were investigated as a new vehicle for the prolonged topical ophthalmic delivery of antibiotic, gatifloxacin. A modified coacervation or ionotropic gelation method was used to produce gatifloxacin-loaded submicroscopic nanoreservoir systems. It was optimised using design of experiments by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the amount of the bioadhesive polymers: CS, ALG and the amount of drug in the formulation. The dependent variables were the particle size, zetapotential, encapsulation efficiency and burst release. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations were selected by feasibility and grid search. Nanoparticles were characterised by FT-IR, DSC, TEM and atomic force microscopy. Drug content, encapsulation efficiency and particle properties such as size, size distribution (polydispersity index) and zetapotential were determined. The designed nanoparticles have average particle size from 205 to 572 nm (polydispersity from 0.325 to 0.489) and zetapotential from 17.6 to 47.8 mV. Nanoparticles revealed a fast release during the first hour followed by a more gradual drug release during a 24-h period following a non-Fickian diffusion process. Box-Behnken experimental design thus facilitated the optimisation of mucoadhesive nanoparticulate carrier systems for prolonged ocular delivery of the drug.

  20. The Effects of Zinc and Iron Oxide Nano-Particles on The Growth and Ion Content of Two Corn Cultivars in Different Soil Salinity

    Directory of Open Access Journals (Sweden)

    2014-07-01

    Full Text Available This study was conducted in order to evaluate the effects of foliar application of nano-particles and ordinary bulk materials of zinc and iron oxide was studied in two corn genotypes (S.C 704 and seed mass in different soil salinity (0,75,150 mM NaCl. The experiment was arranged as factorial in a randomized complete block design with four replications. The results showed that in saline condition Leaf area, shoot and root dry matter, photochemical efficiency, the concentration of K, Fe and Zn in shoot decreased and that of Na and the Na/K ratio increased under saline condition. The interactions of salinity and genotype were significant on leaf area, shoot and root dry matter, Na/K ratio and photochemical efficiency. The application of nano-particles of iron and zinc oxide increased shoot dry matter to a greater degree as compared with ordinary bulk materials. Under saline condition, the application of iron oxide in the form of nano-particles had higher effect on iron uptake by corn plants. However, with an increase in salinity level the superiority of nano form decreased. The application of Nano-particles of iron and zinc as compared to ordinary bulk materials was more effective in alleviating the negative effects of salt stress on the accumulation of zinc in tested plants. This was not evidence in terms of iron accumulation. The results from this experiment showed that the application of nano-particles of iron and zinc promoted plant growth to a greater degree in comparison to ordinary materials of these nutrients. However, the application of nano particles had no advantage in alleviating the effects of salinity on plant growth.

  1. Metal matrix composite of an iron aluminide and ceramic particles and method thereof

    Science.gov (United States)

    Schneibel, Joachim H.

    1997-01-01

    A metal matrix composite comprising an iron aluminide binder phase and a ceramic particulate phase such as titanium diboride, zirconium diboride, titanium carbide and tungsten carbide is made by heating a mixture of iron aluminide powder and particulates of one of the ceramics such as titanium diboride, zirconium diboride, titanium carbide and tungsten carbide in a alumina crucible at about 1450.degree. C. for about 15 minutes in an evacuated furnace and cooling the mixture to room temperature. The ceramic particulates comprise greater than 40 volume percent to about 99 volume percent of the metal matrix composite.

  2. Environmental application of millimetre-scale sponge iron (s-Fe{sup 0}) particles (III): The effect of surface silver

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Yongming [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); South China Subcenter of State Environmental Dioxin Monitoring Center, Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Yu, Yunjiang, E-mail: yuyunjiang@scies.org [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Wang, Xiaoyan [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Zhang, Sukun [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Liu, Runlong [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Innovative Laboratory for Environmental Functional Materials and Environmental Applications of Microwave Irradiation, Guangzhou 510655 (China); Fu, Jianping; Han, Jinglei; Fang, Jiande [South China Institute of Environmental Sciences, Ministry of Environmental Protection (MEP), Guangzhou 510655 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2015-12-15

    Highlights: • Direct reductive deposition reaction achieves surfaced decoration of s-Fe{sup 0} particles. • Ag{sup 0}-s-Fe{sup 0} displays similar removal efficiency of PCP as compared to bimetal of nZVI. • Ag{sup 0}-s-Fe{sup 0} can be utilized under mild reaction condition compared to bimetal of nZVI. • The catalytic mechanism over Ag{sup 0}-s-Fe{sup 0} under US condition is elucidated. - Abstract: To enhance the dechlorination reactivity of millimetric sponge iron (s-Fe{sup 0}), a facile one-pot method was used to decorate s-Fe{sup 0} with Ag{sup +} ions under ambient conditions. The results recorded by X-ray diffraction patterns, X-ray photoelectron spectra and high-resolution transmission electron microscopy demonstrated that the growth of Ag{sup 0} was dominated primarily by (1 1 1) plane with a mean length of ∼20 nm. The roles of Ag{sup 0} loading, catalyst dosage, particle size, initial pH and contaminant concentration were assessed during the removal of pentachlorophenol (PCP). Catalyst recyclability was also studied. The results revealed that 3–5 mm s-Fe{sup 0} particles with 5 wt% Ag{sup 0} loading exhibited the best performance with a dose of 3.0 g per 60 mL PCP solution. In addition, the dechlorination of PCP followed two-step, pseudo-first-order reaction kinetics, and Ag{sup 0}-s-Fe{sup 0} was advantageous compared with bimetals of nanoscale zero-valent iron, iron power and iron flakes. The dechlorination mechanism of PCP over Ag{sup 0}-s-Fe{sup 0} was attributed to the surface Ag{sup 0} decoration, which catalyzed the formation of reactive hydrogen atoms for indirect reaction, and the direct electron transfer via Fe–Ag{sup 0} galvanic cells for direct reaction. This suggests that Ag-based bimetals of s-Fe{sup 0} have great potential in the pretreatment of organic halogen compounds in aqueous solution.

  3. Influence of composition, grain size, and oxide particles on the strength of consolidated ball-milled iron

    Science.gov (United States)

    Benito, J. A.; Gregoire, V.; Casas, C.; Cabrera, J. M.

    2014-08-01

    In this paper iron powders with two oxygen content (0.2 and 0.6% wt.) have been mechanically milled and consolidated by hot static pressing at different temperatures to obtain different grain sizes. At lower temperatures the grain size was in the nanostructured and ultrafine range and with increasing temperature abnormal grain growth was observed for both compositions. This led to the development of bimodal grain size distributions. In the samples with lower oxygen content the grain size and the percentage of coarse grain areas were larger than in the case of high oxygen content. The strength and ductility have been determined by tensile tests. For low oxygen content, the presence of large coarse grains allowed plastic strain in some cases, and for the samples consolidated at higher temperatures, yield strength of 865 MPa with a 8% total strain were obtained. For the samples with high oxygen content plastic deformation was no possible in any case. The observed stress for both compositions was analysed by two approaches, one based exclusively in grain boundary strengthening and the other one based in two effects acting at the same time: grain boundary and particle strengthening. Whereas grain boundary strengthening seems to fit with the strength of the samples in the nanostructured range, when coarse ferrite grains appear the addition of particle strengthening help to get better results. This indicates that the presence of oxides dissolved inside the large grains reinforce the structure of ball-milled iron.

  4. The effect of oxide particles on the strength and ductility of bulk iron with a bimodal grain size distribution

    Energy Technology Data Exchange (ETDEWEB)

    Casas, C.; Tejedor, R. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Rodríguez-baracaldo, R. [Department of Mechanical Engineering, Universidad Nacional de Colombia, Bogotá. Colombia (Colombia); Benito, J.A., E-mail: Josep.a.benito@upc.edu [Department of Materials Science and Metallurgical Engineering, EUETIB, Universitat Politècnica de Catalunya, Comte d' Urgell 187, 08036 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain); Cabrera, J.M. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Fundació CTM Centre Tecnològic de Manresa, Plaça de la Ciencia, 2, 08243 Manresa (Spain)

    2015-03-11

    The strength and ductility of bulk nanostructured and ultrafine-grained iron containing 0.39% oxygen by weight was determined by tensile tests. Samples were obtained by consolidation of milled iron powder at 500 °C. Heat treatments were designed to cover a wide range of grain sizes spanning from 100 to 2000 nm with different percentages of coarse and nanostructured grain areas, which was defined as a bimodal grain size distribution. Transmission electron microscopy was used to determine the diameter, volume fraction and location of oxides in the microstructure. The strength was analysed following two approaches. The first one was based on the strong effect of oxides and involved the use of a mixed particle-grain boundary strengthening model, and the second one was based on simple grain boundary strengthening. The mixed model underestimated the strength of nanostructured samples, whereas the simple grain boundary model worked better. However, for specimens with a bimodal grain size, the fitting of the mixed model was better. In this case, the more effective particle strengthening was related to the dispersion of oxides inside the large ferrite grains. In addition, the bimodal samples showed an acceptable combination of strength and ductility. Again, the ferrite grains containing oxides promoted strain hardening due to the increase in dislocation activity.

  5. Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater--Using humic acid and iron nano-sized colloids as test particles.

    Science.gov (United States)

    Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret; Baun, Anders; Eriksson, Eva

    2015-11-01

    The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution of low-molecular weight PAHs (LMW PAHs), middle-molecular weight PAHs (MMW PAHs) and high-molecular weight PAHs (HMW PAHs) among the fractions was also evaluated. The results from the synthetic suspensions showed that the highest concentrations of the PAHs were found in the Filtrated fractions and, surprisingly, high loads were found in the Dissolved fractions. The PAHs identified in stormwater in the Particulate fractions and Dissolved fractions follow their hydrophobic properties. In most samples >50% of the HMW PAHs were found in the Particulate fractions, while the LMW and MMW PAHs were found to a higher extent in the Filtrated fractions. The highest concentrations of PAHs were present in the stormwater with the highest total suspended solids (TSS); the relative amount of the HMW PAHs was highest in the Particulate fractions (particles>0.7 μm). The highest concentration of PAHs in the Colloidal fraction was found in the sample with occurrence of small nano-sized particles (importance of developing technologies that both can manage particulate matter and effectively remove PAHs present in the Colloidal and Dissolved fractions in stormwater. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effects of pH and particle size on kinetics of nitrobenzene reduction by zero-valent iron.

    Science.gov (United States)

    Dong, Jun; Zhao, Yongsheng; Zhao, Ran; Zhou, Rui

    2010-01-01

    Nitrobenzene has been considered as a significant groundwater contaminant due to its wide usage in explosives, insecticides, herbicides, pharmaceuticals and dyes. Nitrobenzene is of environmental concern because of its toxicity. In the presence of zero-valent iron (ZVI), reduction of the nitro group is the dominant transformation process for nitrobenzene. A series of experiments were carried out to investigate the kinetics of nitrobenzene reduction by ZVI and the effects of pH and ZVI particle size on nitrobenzene removal in groundwater. The results indicated that nitrobenzene could be reduced to aniline by ZVI; the reduction of nitrobenzene by ZVI followed a pseudo first-order kinetics; the observed nitrobenzene reduction rate constant (k(obs)) was 0.0006 min(-1) and the half-life of nitrobenzene (t1/2) was 115.5 min; the mass balance achieved 87.5% for nitrobenzene reduction by the 1 mm ZVI particle and the final removal efficiency was 80.98%. In addition, the pH and ZVI particle size were found to exhibit significant influences on the nitrobenzene reduction. The observed nitrobenzene reduction rate constant linearly decreased with increase pH and the data fitted on polynomial regression equation for the observed nitrobenzene reduction rate constant and ZVI particle size. Therefore, use of ZVI based permeable reactive barrier technology to remedy nitrobenzene contaminated groundwater was feasible.

  7. Removal of polybrominated diphenyl ethers by biomass carbon-supported nanoscale zerovalent iron particles: influencing factors, kinetics, and mechanism.

    Science.gov (United States)

    Fu, Rongbing; Xu, Zhen; Peng, Lin; Bi, Dongsu

    2016-12-01

    In this study, nanoscale zerovalent iron (NZVI) immobilized on biomass carbon was used for the high efficient removal of BDE 209. NZVI supported on biomass carbon minimized the aggregation of NZVI particles resulting in the increased reaction performance. The proposed removal mechanism included the adsorption of BDE 209 on the surface or interior of the biomass carbon NZVI (BC-NZVI) particles and the subsequent debromination of BDE 209 by NZVI while biomass carbon served as an electron shuttle. BC-NZVI particles and the interaction between BC-NZVI particles and BDE 209 were characterized by TEM, XRD, and XPS. The removal reaction followed a pseudo-first-order rate expression under different reaction conditions, and the k obs was higher than that of other NZVI-supported materials. The debromination of BDE 209 by BC-NZVI was a stepwise process from nona-BDE to DE. A proposed pathway suggested that supporting NZVI on biomass carbon has potential as a promising technique for in situ organic-contaminated groundwater remediation.

  8. Ignition of steel alloys by impact of low-velocity iron/inert particles in gaseous oxygen

    Science.gov (United States)

    Benz, Frank J.; Mcilroy, Kenneth; Williams, Ralph E.

    1988-01-01

    The ignition of carbon steel and 316 and 304 stainless steels caused by the impact of low-velocity particles (a standard mixture consisting of 2 g of iron and 3 g of inert materials) in gaseous oxygen was investigated using NASA/White Sands Test Facility for the ignition test, and a subsonic particle impact chamber to accelerate the particles that were injected into flowing oxygen upstream of the target specimen. It was found that the oxygen velocities required to ignite the three alloys were the same as that required to ignite the particle mixture. Ignition occurred at oxygen velocities greater than 45 m/sec at 20 to 24 MPa and was found to be independent of pressure between 2 and 30 MPa. Comparison of the present results and the past results from Wegener (1964) with the Compressed Gas Association (CGA) oxygen velocity limits for safe operations indicates that the CGA limits may be excessively conservative at high pressures and too liberal at low pressures.

  9. Effect of labeling with iron oxide particles or nanodiamonds on the functionality of adipose-derived mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Sinead P Blaber

    Full Text Available Stem cells are increasingly the focus of translational research as well as having emerging roles in human cellular therapy. To support these uses there is a need for improved methods for in vivo cell localization and tracking. In this study, we examined the effects of cell labeling on the in vitro functionality of human adipose-derived mesenchymal stem cells. Our results provide a basis for future in vivo studies investigating implanted cell fate and longevity. In particular, we investigated the effects of two different particles: micron-sized (~0.9 µm fluorescently labeled (Dragon Green superparamagnetic iron oxide particles (M-SPIO particles; and, carboxylated nanodiamonds of ~0.25 µm in size. The effects of labeling on the functionality of adipose-derived MSCs were assessed by in vitro morphology, osteogenic and adipogenic differentiation potential, CD marker expression, cytokine secretion profiling and quantitative proteomics of the intra-cellular proteome. The differentiation and CD marker assays for stem-like functionality were not altered upon label incorporation and no secreted or intra-cellular protein changes indicative of stress or toxicity were detected. These in vitro results indicate that the M-SPIO particles and nanodiamonds investigated in this study are biocompatible with MSCs and therefore would be suitable labels for cell localization and tracking in vivo.

  10. Optimization of nano-scale nickel/iron particles for the reduction of high concentration chlorinated aliphatic hydrocarbon solutions.

    Science.gov (United States)

    Barnes, Robert J; Riba, Olga; Gardner, Murray N; Scott, Thomas B; Jackman, Simon A; Thompson, Ian P

    2010-04-01

    The use of nano-scale particles as a means of environmental remediation still provides a comparatively novel approach for the treatment of contaminated waters. The current study compares the reactivity of micro-scale Fe, nano-scale Fe and nano-scale Ni/Fe (nickel/iron) particles specifically for dechlorination of solutions containing 350 mg L(-1) of TCE (concentration measured at a contaminated site in Derbyshire, UK). The results indicated that employing 1 g L(-1) of reactive material for dechlorination in the monometallic form (both micro- and nano-scale) exhibited very little reduction capability compared with the bimetallic Ni/Fe nano-scale particles, containing 28.9% Ni (in molar), which achieved complete dechlorination of the TCE in solution within 576 h. Experiments were also performed to determine the optimum bimetallic composition of the Ni/Fe particles for TCE reduction. This revealed that 3.2% Ni was the optimum Ni/Fe molar ratio for both maximum dehalogenation performance and minimum release of Ni into solution. Using particles of the most effective bimetallic composition, experiments were carried out to determine the concentration required for optimal TCE reduction. Over the range of nano-scale particle concentrations tested (0.1-9 g L(-1)), reduction rates of TCE increased with greater TCE:nano-scale particle ratios. However, a concentration range of 1-3 g L(-1) was selected as the most appropriate for site remediation, since more concentrated solutions demonstrated only small increases in rates of reaction. Finally, in order to test the long term performance and reactivity of the 3.2% Ni/Fe bimetallic nano-scale particles, weekly spikes of 350 mg L(-1) TCE were injected into a 3 g L(-1) nano-scale particle batch reactor. Results showed that the bimetallic nano-scale particles had the ability to reduce 1750 mg L(-1) TCE and remained active for at least 13 weeks. (c) 2010 Elsevier Ltd. All rights reserved.

  11. Monitoring the injection of microscale zero-valent iron particles for groundwater remediation by means of complex electrical conductivity imaging

    Science.gov (United States)

    Flores Orozco, A.; Velimirovic, M.; Tosco, T.; Kemna, A.; Sapion, H.; Klaas, N.; Sethi, R.; Bastiaens, L.

    2015-12-01

    The injection of nano- and microscale zerovalent iron (ZVI) particles has emerged as a promising technique for groundwater remediation. In particular, ZVI injections offer a suitable alternative for the remediation of areas not accessible with other techniques, such as areas characterized by low hydraulic conductivity. In such cases, the injection is performed at high pressure in order to create preferential flow paths (i.e., fractures). Particle injection via fracturing demands an adequate monitoring of the ZVI delivery to track the migration path of the particles as well as to delineate the extension and distribution of the iron slurry. However, characterization of ZVI injections is to date based mainly on the analysis of groundwater and soil samples, thus, limiting the spatio-temporal resolution of the investigation and making it not suitable for real-time monitoring. To overcome this, here we present the application of the complex conductivity (CC) imaging method to characterize the delivery of guar gum stabilized microscale ZVI (GG-mZVI) particles during a field-scale injection by hydraulic fracturing. Our results demonstrated that CC images provide not only an improved characterization of the contaminant distribution, but also valuable information to identify the migration pathway of the injected GG-mZVI. The relatively short acquisition time of CC datasets permitted to obtain monitoring data with enhanced temporal resolution, i.e., after each injection (every ~15 minutes), while still covering an extended area of investigation in comparison to conventional geochemical monitoring by means of soil and water samples. As presented in Figure 1, the CC images revealed an increase (~20%) in the induced electrical polarization (Φ), upon delivery of ZVI into the targeted area, due to the accumulation of ZVI. Furthermore, larger changes (>50%) occurred in shallow sediments, a few meters away from the injection, suggesting the migration of particles through

  12. Investigation of washing and storage strategy on aging Of Mg-aminoclay (MgAC) coated nanoscale zero-valent iron (nZVI) particles

    DEFF Research Database (Denmark)

    Hwang, Yuhoon; Lee, Young-Chul; Mines, Paul D.

    2014-01-01

    The tendency towards agglomeration and oxidation of nanoscale zero-valent iron (nZVI) particles limits its application for in situ groundwater and soil remediation. Although the effect of surface coatings on nanoparticle stabilization has been commonly practiced, the effect of preparation...... of repulsion between nZVI particles. On the other hand, pre-storage washing is essential, in order to retain nZVI reactivity, by removal of residual reactants in the synthesis mixture. The reactivity of nZVI is examined with three parameters: optical density at 508 nm as a measure of particle concentration......, reactive iron content measured by H2 generation with acid digestion, and nitrate reduction capacity. All three parameters decrease significantly for post-storage washed nZVI, which corresponds to XRD results that exhibit transformation of Fe(0) to iron oxides. The reactivity tests display high linear...

  13. Trends in the evolution of particle morphology with size in colluvial deposits overlying channel iron deposits

    Science.gov (United States)

    Linero, Sandra; Fityus, Stephen; Simmons, John; Lizcano, Arcesio; Cassidy, Jessica

    2017-06-01

    Size limitations of testing equipment often impliy that samples of coarse granular materials must be scalped or scaled, to reduce the size of the constitutive particles, before they can be tested either by triaxial or direct shear in the laboratory. The objective of the investigation is to evaluate the particle shapes in a natural sample of colluvial sediments, to identify potential correlation(s) between shape and size, that could impact shear strength of scaled samples. The material investigated is derived from eroded ancient sedimentary rocks from the Pilbara region of Australia. The fragments have a particle shape ranging from slabs to sub-equant blocks. The observation indicates that there is an increase in the tendency for slabshapes in larger particles. Therefore, scaling inevitably alters the characteristic shapes of the material particles as it implies substituting larger (slabs) particles by smaller (sub-equant) particles. Changes in particle shape distribution may induce changes in material fabric and shear strength and therefore may need to be considered when scaling samples.

  14. Trends in the evolution of particle morphology with size in colluvial deposits overlying channel iron deposits

    Directory of Open Access Journals (Sweden)

    Linero Sandra

    2017-01-01

    Full Text Available Size limitations of testing equipment often impliy that samples of coarse granular materials must be scalped or scaled, to reduce the size of the constitutive particles, before they can be tested either by triaxial or direct shear in the laboratory. The objective of the investigation is to evaluate the particle shapes in a natural sample of colluvial sediments, to identify potential correlation(s between shape and size, that could impact shear strength of scaled samples. The material investigated is derived from eroded ancient sedimentary rocks from the Pilbara region of Australia. The fragments have a particle shape ranging from slabs to sub-equant blocks. The observation indicates that there is an increase in the tendency for slabshapes in larger particles. Therefore, scaling inevitably alters the characteristic shapes of the material particles as it implies substituting larger (slabs particles by smaller (sub-equant particles. Changes in particle shape distribution may induce changes in material fabric and shear strength and therefore may need to be considered when scaling samples.

  15. Are engineered nano iron oxide particles safe? an environmental risk assessment by probabilistic exposure, effects and risk modeling.

    Science.gov (United States)

    Wang, Yan; Deng, Lei; Caballero-Guzman, Alejandro; Nowack, Bernd

    2016-12-01

    Nano iron oxide particles are beneficial to our daily lives through their use in paints, construction materials, biomedical imaging and other industrial fields. However, little is known about the possible risks associated with the current exposure level of engineered nano iron oxides (nano-FeOX) to organisms in the environment. The goal of this study was to predict the release of nano-FeOX to the environment and assess their risks for surface waters in the EU and Switzerland. The material flows of nano-FeOX to technical compartments (waste incineration and waste water treatment plants) and to the environment were calculated with a probabilistic modeling approach. The mean value of the predicted environmental concentrations (PECs) of nano-FeOX in surface waters in the EU for a worst-case scenario (no particle sedimentation) was estimated to be 28 ng/l. Using a probabilistic species sensitivity distribution, the predicted no-effect concentration (PNEC) was determined from ecotoxicological data. The risk characterization ratio, calculated by dividing the PEC by PNEC values, was used to characterize the risks. The mean risk characterization ratio was predicted to be several orders of magnitude smaller than 1 (1.4 × 10 - 4 ). Therefore, this modeling effort indicates that only a very limited risk is posed by the current release level of nano-FeOX to organisms in surface waters. However, a better understanding of the hazards of nano-FeOX to the organisms in other ecosystems (such as sediment) needs to be assessed to determine the overall risk of these particles to the environment.

  16. Effectiveness of Intermittent Preventive Treatment in Pregnancy with Sulphadoxine-Pyrimethamine against Submicroscopic falciparum Malaria in Central Region, Ghana

    Directory of Open Access Journals (Sweden)

    Ekene K. Nwaefuna

    2015-01-01

    Full Text Available Malaria infections undetectable by microscopy but detectable by Polymerase Chain Reaction (PCR (submicroscopic malaria are common in endemic areas like Ghana. Submicroscopic malaria has been linked with severe pregnancy outcomes as well as contributing to malaria transmission. In this cross-sectional study 872 consenting pregnant women (gestation ≥ 20 weeks were recruited from 8 hospitals in Central Region, Ghana, between July and December 2009. Malaria infection was detected by microscopy and PCR. Haemoglobin was measured and anaemia was defined as haemoglobin lower than 11 g/dL. Majority of the women, 555 (63.6%, were Intermittent Preventive Treatment in Pregnancy with Sulphadoxine-Pyrimethamine (IPTp-SP users while 234 (36.4% were nonusers. The prevalence of malaria by microscopy was 20.9% (182/872 and 9.7% (67/688 of microscopy negative women had submicroscopic malaria. IPTp-SP usage significantly (odds ratio = 0.13, 95% confidence interval = 0.07–0.23, p=0.005 reduced the prevalence of submicroscopic malaria as more nonusers (51/234 than users (16/454 were PCR positive. After controlling for other variables the effect of IPTp-SP remained statistically significant (odds ratio = 0.11, 95% confidence interval = 0.02–0.22, p=0.006. These results suggest that Intermittent Preventive Treatment with Sulphadoxine-Pyrimethamine is useful in the reduction of submicroscopic malaria in pregnancy.

  17. Magnetic properties of magnetic liquids with iron-oxide particles - the influence of anisotropy and interactions

    DEFF Research Database (Denmark)

    Johansson, C.; Hanson, M.; Pedersen, Michael Stanley

    1997-01-01

    independent of temperature. Ms increases with decreasing temperature according to an effective Bloch law with an exponent larger than 1.5, as expected for fine magnetic particles. The model of magnetic particles with uniaxial anisotropy and the actual size distribution gives a consistent description...... of independent measurements of the temperature dependence of the hyperfine field and the isothermal magnetization versus field. From this an effective anisotropy constant of about 4.5x10 4 J m-3 is estimated for a particle with diameter 7.5 nm. The magnetic relaxation, as observed in zero...

  18. The Effects of Particle Size, Relative Humidity, and Sulfur Dioxide on Iron Solubility in Atmospheric Particulate Matter

    Science.gov (United States)

    Cartledge, B. T.; Marcotte, A.; Anbar, A. D.; Herckes, P.; Majestic, B. J.

    2014-12-01

    The current study focuses on studying how iron (Fe) solubility is affected by particle size, relative humidity, and exposure to sulfur dioxide (SO2). Fe, the most abundant transition metal in atmospheric particulate matter, plays a critical role in the atmospheric sulfur cycle and is a micronutrient for phytoplankton in remote regions of the ocean. To mimic oceanic particles, iron-containing minerals (hematite, magnetite, goethite, and illite) were resuspended with sodium chloride and size-segregated on Teflon filters into five different size fractions: 10-2.5 μm, 2.5-1.0 μm, 1.0-0.5 μm, 0.5-0.25 μm, and 80%) and arid environment humidity (24%). Trials with no SO2 ­were also performed as comparisons. Total Fe was determined by using microwave-assisted acid digestion and soluble Fe was determined by extracting the samples in a simulated cloud water buffer (pH 4.25, 0.5 mM acetate, 0.5 mM formate, and 0.2 mM ammonium nitrate). Both total and soluble Fe concentrations were determined via inductively-coupled plasma mass spectrometry (ICP-MS). We found that, as particle size decreased, Fe percent solubility increased for hematite, magnetite, and goethite. The percent solubility of Fe in these mineral phases steadily increased from 0.5-10% as particle size decreased. In contrast, the Fe percent solubility in illite was relatively constant for the largest four size fractions but increased dramatically in the smallest size fraction. The percent solubility of Fe in illite ranged from 5-20% as the particle size decreased. Additionally, increased Fe solubility was linked to increased relative humidity with higher percent solubility generally observed in all mineral phases for the samples exposed at the higher humidity. No correlation was observed for the effects of the SO2 on Fe percent solubility. The likely lack of Fe-SO2 interactions were also supported by synchrotron-based x-ray spectroscopy. These results help further the knowledge of how the solubilization of

  19. A general result for the magnetoelastic response of isotropic suspensions of iron and ferrofluid particles in rubber, with applications to spherical and cylindrical specimens

    Science.gov (United States)

    Lefèvre, Victor; Danas, Kostas; Lopez-Pamies, Oscar

    2017-10-01

    This paper puts forth an approximate solution for the effective free-energy function describing the homogenized (or macroscopic) magnetoelastic response of magnetorheological elastomers comprised of non-Gaussian rubbers filled with isotropic suspensions of either iron or ferrofluid particles. The solution is general in that it applies to N = 2 and 3 space dimensions and any arbitrary (non-percolative) isotropic suspension of filler particles. By construction, it is exact in the limit of small deformations and moderate magnetic fields. For finite deformations and finite magnetic fields, its accuracy is demonstrated by means of direct comparisons with full-field simulations for two prominent cases: (i) isotropic suspensions of circular particles and (ii) isotropic suspensions of spherical particles. With the combined objectives of demonstrating the possible benefits of using ferrofluid particles in lieu of the more conventional iron particles as fillers and gaining insight into recent experimental results, the proposed homogenization-based constitutive model is deployed to generate numerical solutions for boundary-value problems of both fundamental and practical significance: those consisting of magnetorheological elastomer specimens of spherical and cylindrical shape that are immersed in air and subjected to a remotely applied uniform magnetic field. It is found that magnetorheological elastomers filled with ferrofluid particles can exhibit magnetostrictive capabilities far superior to those of magnetorheological elastomers filled with iron particles. The results also reveal that the deformation and magnetic fields are highly heterogenous within the specimens and strongly dependent on the shape of these, specially for magnetorheological elastomers filled with iron particles. From an applications perspective, this evidence makes it plain that attempts at designing magnetrostrictive devices based on magnetorheological elastomers need to be approached, in general, as

  20. Structure and magnetic properties of iron-platinum particles with {gamma}-ferric-oxide shell

    Energy Technology Data Exchange (ETDEWEB)

    Basit, L.; Shukoor, I.; Ksenofontov, V.; Fecher, G.H.; Tremel, W.; Felser, C. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Anorganische und Analytische Chemie, Mainz (Germany); Nepijko, S.A.; Schoenhense, G. [Johannes Gutenberg-Universitaet Mainz, Institut fuer Physik, Mainz (Germany); Klimenkov, M. [Forschungszentrum Karlsruhe GmbH, Institut fuer Materialforschung I, Karlsruhe (Germany)

    2009-03-15

    Nanoparticles of solid solution Fe{sub x}Pt{sub 1-x}, where 0.25{>=}x{>=}0 (fcc lattice) with {gamma}-Fe{sub 2}O{sub 3} shell (lattice of the spinel type) were synthesised and characterised by high-resolution transmission electron microscopy, energy dispersive X-ray analysis, electron energy loss spectroscopy, Moessbauer spectroscopy and magnetometry. From the point of view of magnetic properties, such two-phase particles are interesting because their core is antiferromagnetic or paramagnetic (at very small values of x) whereas the shell is ferrimagnetic. The size of the particles was in the range of several nanometers. The Moessbauer measurements revealed a blocking temperature of about 100 K above which the particles are superparamagnetic. Towards lower temperatures, the magnetic characteristics of an ensemble of such particles show an increase of magnetic rigidity. (orig.)

  1. Transport and retention of xanthan gum-stabilized microscale zero-valent iron particles in saturated porous media.

    Science.gov (United States)

    Xin, Jia; Tang, Fenglin; Zheng, Xilai; Shao, Haibing; Kolditz, Olaf

    2016-01-01

    Microscale zero valent iron (mZVI) is a promising material for in-situ contaminated groundwater remediation. However, its usefulness has been usually inhibited by mZVI particles' low mobility in saturated porous media for sedimentation and deposition. In our study, laboratory experiments, including sedimentation studies, rheological measurements and transport tests, were conducted to investigate the feasibility of xanthan gum (XG) being used as a coating agent for mZVI particle stabilization. In addition, the effects of XG concentration, flow rate, grain diameter and water chemistry on XG-coated mZVI (XG-mZVI) particle mobility were explored by analyzing its breakthrough curves and retention profiles. It was demonstrated that XG worked efficiently to enhance the suspension stability and mobility of mZVI particles through the porous media as a shear thinning fluid, especially at a higher concentration level (3 g/L). The results of the column study showed that the mobility of XG-mZVI particles increased with an increasing flow rate and larger grain diameter. At the highest flow rate (2.30 × 10(-3) m/s) within the coarsest porous media (0.8-1.2 mm), 86.52% of the XG-mZVI flowed through the column. At the lowest flow rate (0.97 × 10(-4) m/s) within the finest porous media (0.3-0.6 mm), the retention was dramatically strengthened, with only 48.22% of the particles flowing through the column. The XG-mZVI particles appeared to be easily trapped at the beginning of the column especially at a low flow rate. In terms of two representative water chemistry parameters (ion strength and pH value), no significant influence on XG-mZVI particle mobility was observed. The experimental results suggested that straining was the primary mechanism of XG-mZVI retention under saturated condition. Given the above results, the specific site-related conditions should be taken into consideration for the design of a successful delivery system to achieve a compromise between

  2. Genotoxic effects of high-energy iron particles in human lymphoblasts differing in radiation sensitivity

    Science.gov (United States)

    Evans, H. H.; Horng, M. F.; Evans, T. E.; Jordan, R.; Schwartz, J. L.

    2001-01-01

    The effects of (56)Fe particles and (137)Cs gamma radiation were compared in TK6 and WTK1 human lymphoblasts, two related cell lines which differ in TP53 status and in the ability to rejoin DNA double-strand breaks. Both cell lines were more sensitive to the cytotoxic and clastogenic effects of (56)Fe particles than to those of gamma rays. However, the mutagenicity of (56)Fe particles and gamma rays at the TK locus was the same per unit dose and was higher for gamma rays than for (56)Fe particles at isotoxic doses. The respective RBEs for TK6 and WTK1 cells were 1.5 and 1.9 for cytotoxicity and 2.5 and 1.9 for clastogenicity, but only 1 for mutagenicity. The results indicate that complex lesions induced by (56)Fe particles are repaired less efficiently than gamma-ray-induced lesions, leading to fewer colony-forming cells, a slightly higher proportion of aberrant cells at the first division, and a lower frequency of viable mutants at isotoxic doses. WTK1 cells (mutant TP53) were more resistant to the cytotoxic effects of both gamma rays and (56)Fe particles, but showed greater cytogenetic and mutagenic damage than TK6 cells (TP53(+)). A deficiency in the number of damaged TK6 cells (a) reaching the first mitosis after exposure and (b) forming viable mutants can explain these results.

  3. Submicroscopic Plasmodium falciparum gametocyte carriage is common in an area of low and seasonal transmission in Tanzania

    DEFF Research Database (Denmark)

    Shekalaghe, Seif A; Bousema, J Teun; Kunei, Karaine K

    2007-01-01

    . In this study, we investigated submicroscopic asexual parasitaemia and gametocytaemia in inhabitants of an area of hypoendemic and seasonal malaria in Tanzania. METHODS: Two cross-sectional malariometric surveys were conducted in the dry and wet seasons of 2005 in villages in lower Moshi, Tanzania. Finger prick...... blood samples were taken to determine the prevalence of P. falciparum parasites by microscopy, rapid diagnostic test and real-time nucleic acid sequence-based amplification (QT-NASBA). RESULTS: 2752 individuals participated in the surveys, of whom 1.9% (51/2721) had microscopically confirmed asexual...... reveal that carriage of submicroscopic asexual parasite and gametocyte densities is relatively common in this low transmission area. Submicroscopic gametocytaemia is likely to be responsible for maintaining malarial transmission in the study area....

  4. Quantitative image analysis of laminin immunoreactivity in skin basement membrane irradiated with 1 GeV/nucleon iron particles

    Science.gov (United States)

    Costes, S.; Streuli, C. H.; Barcellos-Hoff, M. H.

    2000-01-01

    We previously reported that laminin immunoreactivity in mouse mammary epithelium is altered shortly after whole-body irradiation with 0.8 Gy from 600 MeV/nucleon iron ions but is unaffected after exposure to sparsely ionizing radiation. This observation led us to propose that the effect could be due to protein damage from the high ionization density of the ion tracks. If so, we predicted that it would be evident soon after radiation exposure in basement membranes of other tissues and would depend on ion fluence. To test this hypothesis, we used immunofluorescence, confocal laser scanning microscopy, and image segmentation techniques to quantify changes in the basement membrane of mouse skin epidermis. At 1 h after exposure to 1 GeV/nucleon iron ions with doses from 0.03 to 1.6 Gy, neither the visual appearance nor the mean pixel intensity of laminin in the basement membrane of mouse dorsal skin epidermis was altered compared to sham-irradiated tissue. This result does not support the hypothesis that particle traversal directly affects laminin protein integrity. However, the mean pixel intensity of laminin immunoreactivity was significantly decreased in epidermal basement membrane at 48 and 96 h after exposure to 0.8 Gy 1 GeV/nucleon iron ions. We confirmed this effect with two additional antibodies raised against affinity-purified laminin 1 and the E3 fragment of the long-arm of laminin 1. In contrast, collagen type IV, another component of the basement membrane, was unaffected. Our studies demonstrate quantitatively that densely ionizing radiation elicits changes in skin microenvironments distinct from those induced by sparsely ionizing radiation. Such effects may might contribute to the carcinogenic potential of densely ionizing radiation by altering cellular signaling cascades mediated by cell-extracellular matrix interactions.

  5. Improving Powder Magnetic Core Properties via Application of Thin, Insulating Silica-Nanosheet Layers on Iron Powder Particles

    Directory of Open Access Journals (Sweden)

    Toshitaka Ishizaki

    2016-12-01

    Full Text Available A thin, insulating layer with high electrical resistivity is vital to achieving high performance of powder magnetic cores. Using layer-by-layer deposition of silica nanosheets or colloidal silica over insulating layers composed of strontium phosphate and boron oxide, we succeeded in fabricating insulating layers with high electrical resistivity on iron powder particles, which were subsequently used to prepare toroidal cores. The compact density of these cores decreased after coating with colloidal silica due to the substantial increase in the volume, causing the magnetic flux density to deteriorate. Coating with silica nanosheets, on the other hand, resulted in a higher electrical resistivity and a good balance between high magnetic flux density and low iron loss due to the thinner silica layers. Transmission electron microscopy images showed that the thickness of the colloidal silica coating was about 700 nm, while that of the silica nanosheet coating was 30 nm. There was one drawback to using silica nanosheets, namely a deterioration in the core mechanical strength. Nevertheless, the silica nanosheet coating resulted in nanoscale-thick silica layers that are favorable for enhancing the electrical resistivity.

  6. Substantial asymptomatic submicroscopic Plasmodium carriage during dry season in low transmission areas in Senegal: Implications for malaria control and elimination.

    Science.gov (United States)

    Niang, Makhtar; Thiam, Laty Gaye; Sane, Rokhaya; Diagne, Nafissatou; Talla, Cheikh; Doucoure, Souleymane; Faye, Joseph; Diop, Fode; Badiane, Abdoulaye; Diouf, Babacar; Camara, Diogop; Diene-Sarr, Fatoumata; Sokhna, Cheikh; Richard, Vincent; Toure-Balde, Aissatou

    2017-01-01

    In the progress towards malaria elimination, the accurate diagnosis of low-density asymptomatic infections is critical. Low-density asymptomatic submicroscopic malaria infections may act as silent reservoirs that maintain low-level residual malaria transmission in the community. Light microscopy, the gold standard in malaria diagnosis lacks the sensitivity to detect low-level parasitaemia. In this study, the presence and prevalence of submicroscopic Plasmodium carriage were investigated to estimate the parasites reservoir among asymptomatic individuals living in low transmission areas in Dielmo and Ndiop, Senegal during the dry season. A total of 2,037 blood samples were collected during cross-sectional surveys prior the malaria transmission season in July 2013 (N = 612), June 2014 (N = 723) and June 2015 (N = 702) from asymptomatic individuals living in Dielmo and Ndiop, Senegal. Samples were used to determine the prevalence of submicroscopic Plasmodium carriage by real time PCR (qPCR) in comparison to microscopy considered as gold standard. The prevalence of submicroscopic Plasmodium carriage was 3.75% (23/612), 12.44% (90/723) and 6.41% (45/702) in 2013, 2014 and 2015, respectively. No Plasmodium carriage was detected by microscopy in 2013 while microscopy-based prevalence of Plasmodium carriage accounted for only 0.27% (2/723) and 0.14% (1/702) in 2014 and 2015, respectively. Plasmodium falciparum accounted for the majority of submicroscopic infections and represented 86.95% (20/23), 81.11% (73/90) and 95.55 (43/45) of infections in 2013, 2014 and 2015 respectively. Low-density submicroscopic asymptomatic Plasmodium carriage is common in the study areas during the dry season indicating that traditional measures are insufficient to assess the scale of parasite reservoir when transmission reaches very low level. Control and elimination strategies may wish to consider using molecular methods to identify parasites carriers to guide Mass screening and Treatment

  7. Problems of Electromagnetic Filtration of Technological Liquid on the Basis of Iron-Containing Particle Deposition in High-Gradient Magnetic Field

    Directory of Open Access Journals (Sweden)

    R. A. Muradova

    2006-01-01

    Full Text Available Conventional methods for separation of liquid systems are out of use for cleaning liquid products of chemical technology from finely dispersed micro-quantity of iron-containing particles. Majority of these impurities is characterized by magneto-receptive behavior, in other words they exhibit a capability for magnetic precipitation; so application of magnetic precipitating filters shows promise for a removal of such particles.

  8. Grain size, morphometry and mineralogy of airborne input in the Canary basin: evidence of iron particle retention in the mixed layer

    Directory of Open Access Journals (Sweden)

    Alfredo Jaramillo-Vélez

    2016-09-01

    Full Text Available Aeolian dust plays an important role in climate and ocean processes. Particularly, Saharan dust deposition is of importance in the Canary Current due to its content of iron minerals, which are fertilizers of the ocean. In this work, dust particles are characterized mainly by granulometry, morphometry and mineralogy, using image processing and scanning northern Mauritania and the Western Sahara. The concentration of terrigenous material was measured in three environments: the atmosphere (300 m above sea level, the mixed layer at 10 m depth, and 150 m depth. Samples were collected before and during the dust events, thus allowing the effect of Saharan dust inputs in the water column to be assessed. The dominant grain size was coarse silt. Dominant minerals were iron oxy-hydroxides, silicates and Ca-Mg carbonates. A relative increase of iron mineral particles (hematite and goethite was detected in the mixed layer, reflecting a higher permanence of iron in the water column despite the greater relative density of these minerals in comparison with the other minerals. This higher iron particle permanence does not appear to be explained by physical processes. The retention of this metal by colloids or microorganisms is suggested to explain its long residence time in the mixed layer.

  9. The synthesis of clusters of iron oxides in mesopores of monodisperse spherical silica particles

    Science.gov (United States)

    Stovpiaga, E. Yu.; Eurov, D. A.; Kurdyukov, D. A.; Smirnov, A. N.; Yagovkina, M. A.; Grigorev, V. Yu.; Romanov, V. V.; Yakovlev, D. R.; Golubev, V. G.

    2017-08-01

    The method of obtaining nanoclusters α-Fe2O3 in the pores of monodisperse spherical particles of mesoporous silica ( mSiO2) by a single impregnation of the pores with a melt of crystalline hydrate of ferric nitrate and its subsequent thermal destruction has been proposed. Fe3O4 nanoclusters are synthesized from α-Fe2O3 in the pores by reducing in thermodynamically equilibrium conditions. Then particles containing Fe3O4 were annealed in oxygen for the conversion of Fe3O4 back to α-Fe2O3. In the result, the particles with the structure of the core-shell mSiO2/Fe3O4@ mSiO2/α-Fe2O3 are obtained. The composition and structure of synthesized materials as well as the field dependence of the magnetic moment on the magnetic field strength have been investigated.

  10. Uncovering the local inelastic interactions during manufacture of ductile cast iron: How the substructure of the graphite particles can induce residual stress concentrations in the matrix

    DEFF Research Database (Denmark)

    Andriollo, Tito; Hellström, Kristina; Sonne, Mads Rostgaard

    2018-01-01

    Recent X-ray diffraction (XRD) measurements have revealed that plastic deformation and a residual elastic strain field can be present around the graphite particles in ductile cast iron after manufacturing, probably due to some local mismatch in thermal contraction. However, as only one component....... First, a ma terial equivalent to the ductile cast iron matrix is manufactured and subjected to dilato- metric and high-temperature tensile tests. Subsequently, a two-scale hierarchical top-down model is devised, calibrated on the basis of the collected data and used to simulate the interaction between...... structure of the graphite particles. In contrast to common belief, these results thus suggest that ductile cast iron parts cannot be considered, in general, as stress-free at the microstructural scale....

  11. Nanoscale science and engineering forum (706c) design of solid lipid particles with iron oxide quantum dots for the delivery of therapeutic agents

    Science.gov (United States)

    Solid lipid particles provide a method to encapsulate and control the release of drugs in vivo but lack the imaging capability provided by CdS quantum dots. This shortcoming was addressed by combining these two technologies into a model system that uses iron oxide as a non-toxic imaging component in...

  12. Growth of airway epithelial cells at an air-liquid interface changes both the response to particle exposure and iron homeostasis

    Science.gov (United States)

    We tested the hypothesis that 1) relative to submerged cells, airway epithelial cells grown at an air-liquid interface and allowed to differentiate would have an altered response to particle exposure and 2) that these differences would be associated with indices of iron homeostas...

  13. Distinguishing magnetic particle size of iron oxide nanoparticles with first-order reversal curves

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Monika; Hirt, Ann M., E-mail: ann.hirt@erdw.ethz.ch [Department of Earth Sciences, Institute of Geophysics, ETH-Zurich, Sonneggstrasse 5, CH-8092 Zurich (Switzerland); Widdrat, Marc; Faivre, Damien [Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm, D-14424 Potsdam (Germany); Tompa, Éva; Pósfai, Mihály [Department of Earth and Environmental Sciences, University of Pannonia, Egyetem u. 10, H-8200 Veszprém (Hungary); Uebe, Rene; Schüler, Dirk [Department Biologie I, LMU Munich, Großhaderner Str. 2, D-82152 Martinsried (Germany)

    2014-09-28

    Magnetic nanoparticles encompass a wide range of scientific study and technological applications. The success of using the nanoparticles in various applications demands control over size, dispersibility, and magnetics. Hence, the nanoparticles are often characterized by transmission electron microscopy (TEM), X-ray diffraction, and magnetic hysteresis loops. TEM analysis requires a thin layer of dispersed particles on the grid, which may often lead to particle aggregation thus making size analysis difficult. Magnetic hysteresis loops on the other hand provide information on the bulk property of the material without discriminating size, composition, and interaction effects. First order reversal curves (FORCs), described as an assembly of partial hysteresis loops originating from the major loop are efficient in identifying the domain size, composition, and interaction in a magnetic system. This study presents FORC diagrams on a variety of well-characterized biogenic and synthetic magnetite nanoparticles. It also introduces deconvoluted reversible and irreversible components from FORC as an important method for obtaining a semi-quantitative measure of the effective magnetic particle size. This is particularly important in a system with aggregation and interaction among the particles that often leads to either the differences between physical size and effective magnetic size. We also emphasize the extraction of secondary components by masking dominant coercivity fraction on FORC diagram to explore more detailed characterization of nanoparticle systems.

  14. Iron ore particles on four seaweed species from Camburi Beach (Espírito Santo state, Brazil

    Directory of Open Access Journals (Sweden)

    Cristina Aparecida Gomes Nassar

    2006-09-01

    Full Text Available The present study estimated the iron-ore concentration found on four species of seaweed. The species tested grow on a site heavily contaminated by this ore, in the city of Vitória, state of Espírito Santo, Brazil. Under natural conditions, the iron ore reached a temperature 5.0ºC higher than the sand on a sunny day. All the species had iron ore adhered to their fronds. Udotea cyathiformis was the species with the highest iron-ore concentration varing from 0.07 to 0.90 g wet weight, followed by Lobophora variegata (from 0.07 to 0.62 g wet weight, Padina gymnospora (from 0.08 to 0.55 g wet weight and Ulva fasciata (from 0.05 to 0.25 g wet weight. Even after four changes of water over a 12-hour period, the fronds still had particles adhered to their outside cell wall. All the species showed similar tendencies to release the iron, with the highest percentage of particles (40 to 60% released in the first change of water.Minério de ferro particulado sobre quatro macroalgas da Praia de Camburi (Estado do Espírito Santo-Brasil. O presente trabalho determinou a concentração de minério de ferro presente em quatro macroalgas. As espécies testadas ocorrem em um local extremamente contaminado por este particulado, na cidade de Vitória, Estado do Espírito Santo, Brasil. Sob condições naturais, o minério de ferro alcançou um temperatura de até 5,0ºC acima da temperatura da areia em um dia ensolarado.Todas as espécies estudadas apresentavam minério em suas paredes externas. A espécie Udotea cyathiformis apresentou a maior concentração de minério em sua fronde variando de 0,07 a 0,90 g massa úmida, seguida por Lobophora variegata (de 0,07 a 0,62 g massa úmida, Padina gymnospora (de 0,08 a 0,55 g massa úmida e Ulva fasciata (de 0,05 a 0,25 g massa úmida. Mesmo após sucessivas trocas de água, as frondes ainda apresentavam partículas aderidas às suas paredes celulares externas. As espécies apresentaram a mesma tendência de libera

  15. Effect of rhodium traces on the reducibility of silica-supported iron particles

    KAUST Repository

    Bonnefille, Eric

    2012-06-19

    Fe/SiO 2 and Rh-Fe/SiO 2 catalysts with increasing Fe/Rh ratio have been prepared and characterized by TEM, XRD, oxygen adsorption and Mössbauer spectroscopy. It was confirmed that Fe/SiO 2 catalysts cannot be reduced under hydrogen flow, to more than 50 % whatever the temperature in the 200-500 °C range and shown that the presence of even a small amount of Rh (Fe/Rh ≤2,000) promoted the reduction of iron up to 85-95 %. This promoting effect also took place with a Fe/SiO 2 + Rh/SiO 2 physical mixture (Fe/Rh B2,000). Therefore, the occurrence of a hydrogen spillover effect may be involved in the observed process. © 2012 Springer Science+Business Media, LLC.

  16. Submicroscopic malaria infections in pregnant women from six departments in Haiti.

    Science.gov (United States)

    Elbadry, Maha A; Tagliamonte, Massimiliano S; Raccurt, Christian P; Lemoine, Jean F; Existe, Alexandre; Boncy, Jacques; Weppelmann, Thomas A; Dame, John B; Okech, Bernard A

    2017-08-01

    To describe the epidemiology of malaria in pregnancy in Haiti. Cross-sectional study among pregnant women in six departments of Haiti. After obtaining informed consent, whole blood samples and demographic surveys were collected to investigate malaria prevalence, anaemia and socio-behavioural risk factors for infection, respectively. A total of 311 pregnant women were screened for Plasmodium falciparum infection using a rapid diagnostic test (RDT), microscopy and a novel, quantitative reverse transcriptase polymerase chain reaction method (qRT-PCR). Overall, 1.2% (4/311) of pregnant women were tested positive for malaria infection by both microscopy and RDT. However, using the qRT-PCR, 16.4% (51/311) of pregnant women were positive. The prevalence of malaria infection varied with geographical locations ranging between 0% and 46.4%. Additionally, 53% of pregnant women had some form of anaemia; however, no significant association was found between anaemia and submicroscopic malaria infection. The socio-behavioural risk factors identified to be protective of malaria infection were marital status (P < 0.05) and travel within one month prior to screening (P < 0.05). This study is the first to document the high prevalence of submicroscopic malaria infections among pregnant women in Haiti and identify social and behavioural risk factors for disease transmission. © 2017 John Wiley & Sons Ltd.

  17. Nanohybrids of magnetic iron-oxide particles in hydrophobic organoclays for oil recovery.

    Science.gov (United States)

    Hsu, Ru-Siou; Chang, Wen-Hsin; Lin, Jiang-Jen

    2010-05-01

    Nanohybrids with magnetic iron-oxide nanoparticles (FeNPs) embedded in the multilayered silicate clay were synthesized by in situ Fe(2+)/Fe(3+) coprecipitation. The natural clay, sodium montmorillonite (Na(+)-MMT), was first modified with hydrophobic poly(oxypropylene)amine salts (POP at 2000 and 4000 g/mol M(w)). The two POP-intercalated organoclays, with a silicate interlayer expansion from 1.2 to 5.2 and 9.2 nm, respectively, are suitable for embedding FeNPs. The presence of POP organics in layered structure created the space for intercalating with FeNPs of 2-4 nm in diameter, observed by transmission electronic microscope. The synthesized nanohybrids of POP4000/MMT-FeNP was composed of 17% iron oxide and 51 wt % POP within the silicate basal spacing of 5.0 nm. In contrast, the lower molecular weight of POP2000 intercalated MMT failed to encapsulate FeNPs in a significant amount, but resulting a "crowding-out effect" that caused the silicate interlayer space to shrink from 5.2 to 1.8 nm because of the replacement of the POP salt by Fe(2+)/Fe(3+) ions. The synthesis required the use of high molecular weight POP4000 and low temperatures (<4 degrees C) for a better dispersion in the reaction medium. The presence of POP in the layered silicate facilitated a homogeneous POP/MMT in water, associating with Fe(2+)/Fe(3+) ions and spatially accommodating for the subsequently generated FeNPs. The synthesized nanostructure consisting of POP and FeNP could be used as a pollutant remedy because of its ability to adsorbing crude oil and it is maneuverable under an applied magnetism.

  18. Mechanical disruption of tumors by iron particles and magnetic field application results in increased anti-tumor immune responses.

    Directory of Open Access Journals (Sweden)

    Myriam N Bouchlaka

    Full Text Available The primary tumor represents a potential source of antigens for priming immune responses for disseminated disease. Current means of debulking tumors involves the use of cytoreductive conditioning that impairs immune cells or removal by surgery. We hypothesized that activation of the immune system could occur through the localized release of tumor antigens and induction of tumor death due to physical disruption of tumor architecture and destruction of the primary tumor in situ. This was accomplished by intratumor injection of magneto-rheological fluid (MRF consisting of iron microparticles, in Balb/c mice bearing orthotopic 4T1 breast cancer, followed by local application of a magnetic field resulting in immediate coalescence of the particles, tumor cell death, slower growth of primary tumors as well as decreased tumor progression in distant sites and metastatic spread. This treatment was associated with increased activation of DCs in the draining lymph nodes and recruitment of both DCs and CD8(+T cells to the tumor. The particles remained within the tumor and no toxicities were observed. The immune induction observed was significantly greater compared to cryoablation. Further anti-tumor effects were observed when MRF/magnet therapy was combined with systemic low dose immunotherapy. Thus, mechanical disruption of the primary tumor with MRF/magnetic field application represents a novel means to induce systemic immune activation in cancer.

  19. Removal of chromium(VI) from wastewater by nanoscale zero-valent iron particles supported on multiwalled carbon nanotubes.

    Science.gov (United States)

    Lv, Xiaoshu; Xu, Jiang; Jiang, Guangming; Xu, Xinhua

    2011-11-01

    For the first time, nanoscale zero-valent iron (nZVI)-multiwalled carbon nanotube (MWCNT) nanocomposites were adopted to remove Cr(VI) from wastewater. Such composites were prepared through depositing nZVI particles onto MWCNTs by in situ reduction of ferrous sulfate and then characterized by TEM, SEM and XRD. The results showed that nZVI particles could disperse on the surface or into the network of MWCNTs. Compared to bare nZVI or nZVI-activated carbon composites, the nZVI-MWCNT nanocomposites exhibited around 36% higher efficiency on Cr(VI) removal. The mass ratio of nZVI to MWCNTs was optimized at 1:2, at ionic strength of 0.05M NaCl. The reaction followed a pseudo first-order model under different initial Cr(VI) concentrations and pHs. Low pH and initial Cr(VI) concentration could increase both removal efficiency and rate constants. Anions, such as SO(4)(2-), NO(3)(-) and HCO(3)(-), exhibited negative effects on the removal of Cr(VI), while the effects of PO(4)(3-) and SiO(3)(2-) were insignificant. Overall, nZVI-MWCNT nanocomposites offer a promising alternative material for the removal of Cr(VI) ions from wastewater. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Interfacial electronic structure of electrodeposited Ag nanoparticles on iron oxide nanorice particles

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Ku [Dept. of Chemistry, Yeungnam University, Gyeongsan (Korea, Republic of)

    2016-12-15

    A bimetallic hybrid nanostructure of uni- formly electrodeposited Ag NPs on an Fe oxide nanorice particle template was developed. Figure 6 schematically illustrates uniform electrodeposition of Ag NPs on Fe oxide nanorice supported on a Si substrate. According to Ar + ion depth-probling XPS spectra, the electrodeposited Ag NPs are metallic, and the Fe oxide nanorice particles consist of a metallic shell covered by ultrathin FeOOH or Fe 2 O 3 shells. When the template was functionalized with 1,4-diisocyanobenzene, one terminal NC group was bridge- bonded as in the N C form on the Fe surface. The newly developed selective facial electrodeposition method will be very useful for facial fabrication of bimetallic hybrid systems for diverse application areas.

  1. Charge state distributions of iron in gradual solar energetic particle events

    Science.gov (United States)

    Ostryakov, V. M.; Stovpyuk, M. F.

    1999-11-01

    The energy and charge spectra of Fe ions accelerated in gradual events are calculated numerically. Our results are compared with the available observations. Stripping of Fe ions by thermal electrons and protons during ion acceleration in the solar corona results in the dependence of mean charge \\barq_Fe on energy. We consider the influence of varying plasma parameters (temperature T, number density N, and spectral index of turbulence S) on the charge distribution of iron. Our calculations indicate T~10^6 K and N~(0.5-1)x10^10 cm^-3 at the accelerating site, provided the characteristic acceleration time is about 1 s. The calculated charge spectra for S>2 and S<2 turn out to be different, but some theoretical and experimental uncertainties do not yet allow this parameter to be extracted from observational data. The theoretically obtained charge distributions of Fe could be important in the light of ACE spacecraft data which are currently available for analysis.

  2. Spatial learning and memory deficits induced by exposure to iron-56-particle radiation

    Science.gov (United States)

    Shukitt-Hale, B.; Casadesus, G.; McEwen, J. J.; Rabin, B. M.; Joseph, J. A.

    2000-01-01

    It has previously been shown that exposing rats to particles of high energy and charge (HZE) disrupts the functioning of the dopaminergic system and behaviors mediated by this system, such as motor performance and an amphetamine-induced conditioned taste aversion; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, spatial learning and memory were assessed in the Morris water maze 1 month after whole-body irradiation with 1.5 Gy of 1 GeV/nucleon high-energy (56)Fe particles, to test the cognitive behavioral consequences of radiation exposure. Irradiated rats demonstrated cognitive impairment compared to the control group as seen in their increased latencies to find the hidden platform, particularly on the reversal day when the platform was moved to the opposite quadrant. Also, the irradiated group used nonspatial strategies during the probe trials (swim with no platform), i.e. less time spent in the platform quadrant, fewer crossings of and less time spent in the previous platform location, and longer latencies to the previous platform location. These findings are similar to those seen in aged rats, suggesting that an increased release of reactive oxygen species may be responsible for the induction of radiation- and age-related cognitive deficits. If these decrements in behavior also occur in humans, they may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere.

  3. Exposure vs toxicity levels of airborne quartz, metal and carbon particles in cast iron foundries.

    Science.gov (United States)

    Moroni, Beatrice; Viti, Cecilia; Cappelletti, David

    2014-01-01

    Aerosol dust samples and quartz raw materials from different working stations in foundry plants were characterized in order to assess the health risk in this working environment. Samples were analysed by scanning and transmission electron microscopy coupled with image analysis and microanalysis, and by cathodoluminescence spectroscopy. In addition, the concentration and the solubility degree of Fe and other metals of potential health effect (Mn, Zn and Pb) in the bulk samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, the results indicate substantial changes in quartz crystal structure and texture when passing from the raw material to the airborne dust, which include lattice defects, non-bridging oxygen hole centres and contamination of quartz grains by metal and/or graphite particles. All these aspects point towards the relevance of surface properties on reactivity. Exposure doses have been estimated based on surface area, and compared with threshold levels resulting from toxicology. The possible synergistic effects of concomitant exposure to inhalable magnetite, quartz and/or graphite particles in the same working environment have been properly remarked.

  4. Interaction of Heavy Metal Ions with Carbon and Iron Based Particles

    Directory of Open Access Journals (Sweden)

    Dana Fialova

    2014-03-01

    Full Text Available Due to the rapid development of industry and associated production of toxic waste, especially heavy metals, there is a great interest in creating and upgrading new sorption materials to remove these pollutants from the environment. This study aims to determine the effectiveness of different carbon forms (graphene, expanded carbon, multi-wall nanotubes and paramagnetic particles (Fe2O3 for adsorption of cadmium(II, lead(II, and copper(II on its surface, with different interaction time from 1 min to 24 h. The main attention is paid to the detection of these metals using differential pulse voltammetry. Based on the obtained results, graphene and Fe2O3 are found to be good candidates for removal of heavy metals from the environment.

  5. Scaling Laws at the Nano Size: The Effect of Particle Size and Shape on the Magnetism and Relaxivity of Iron Oxide Nanoparticle Contrast Agents.

    Science.gov (United States)

    Smolensky, Eric D; Park, Hee-Yun E; Zhou, Yue; Rolla, Gabriele A; Marjańska, Małgorzata; Botta, Mauro; Pierre, Valérie C

    2013-06-14

    The magnetic properties of iron oxide nanoparticles govern their relaxivities and efficacy as contrast agents for MRI. These properties are in turn determined by their composition, size and morphology. Herein we present a systematic study of the effect of particle size and shape of magnetite nanocrystals synthesized by thermal decompositions of iron salts on both their magnetism and their longitudinal and transverse relaxivities, r 1 and r 2 , respectively. Faceted nanoparticles demonstrate superior magnetism and relaxivities than spherical nanoparticles of similar size. For faceted nanoparticles, but not for spherical ones, r 1 and r 2 further increase with increasing particle size up to a size of 18 nm. This observation is in accordance with increasing saturation magnetization for nanoparticles increasing in size up to 12 nm, above which a plateau is observed. The NMRD (Nuclear Magnetic Resonance Dispersion) profiles of MIONs (Magnetic Iron Oxide Nanoparticles) display an increase in longitudinal relaxivity with decreasing magnetic field strength with a plateau below 1 MHz. The transverse relaxivity shows no dependence on the magnetic field strength between 20 MHz and 500 MHz. These observations translate to phantom MR images: in T 1 -weighted SWIFT (SWeep imaging with Fourier Transform) images MIONs have a positive contrast with little dependence on particle size, whereas in T 2 -weighted gradient-echo images MIONs create a negative contrast which increases in magnitude with increasing particle size. Altogether, these results will enable the development of particulate MRI contrast agents with enhanced efficacy for biomedical and clinical applications.

  6. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  7. NMR-based metabonomic analyses of the effects of ultrasmall superparamagnetic particles of iron oxide (USPIO) on macrophage metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jianghua [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics (China); Zhao Jing [China Institute of Atomic Energy (China); Hao Fuhua [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics (China); Chen Chang [Institute of Biophysics, The Chinese Academy of Sciences, National Laboratory of Biomacromolecules (China); Bhakoo, Kishore [Singapore Bioimaging Consortium Agency for Science, Technology and Research (A-STAR) (Singapore); Tang, Huiru, E-mail: huiru.tang@wipm.ac.cn [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics (China)

    2011-05-15

    The metabonomic changes in murine RAW264.7 macrophage-like cell line induced by ultrasmall superparamagnetic particles of iron oxides (USPIO) have been investigated, by analyzing both the cells and culture media, using high-resolution NMR in conjunction with multivariate statistical methods. Upon treatment with USPIO, macrophage cells showed a significant decrease in the levels of triglycerides, essential amino acids such as valine, isoleucine, and choline metabolites together with an increase of glycerophospholipids, tyrosine, phenylalanine, lysine, glycine, and glutamate. Such cellular responses to USPIO were also detectable in compositional changes of cell media, showing an obvious depletion of the primary nutrition molecules, such as glucose and amino acids and the production of end-products of glycolysis, such as pyruvate, acetate, and lactate and intermediates of TCA cycle such as succinate and citrate. At 48 h treatment, there was a differential response to incubation with USPIO in both cell metabonome and medium components, indicating that USPIO are phagocytosed and released by macrophages. Furthermore, information on cell membrane modification can be derived from the changes in choline-like metabolites. These results not only suggest that NMR-based metabonomic methods have sufficient sensitivity to identify the metabolic consequences of murine RAW264.7 macrophage-like cell line response to USPIO in vitro, but also provide useful information on the effects of USPIO on cellular metabolism.

  8. Effect of Cr(VI) concentration on gas and particle production during iron oxidation in aqueous solutions containing Cl- ions.

    Science.gov (United States)

    Ahn, Hyangsig; Jo, Ho Young; Ryu, Ji-Hun; Koh, Yong-Kwon

    2017-02-01

    Zero-valent iron (ZVI) is commonly used as a medium in permeable reactive barriers (PRBs) because of its high reducing ability. The generation of H2 gas in PRBs, however, can decrease the permeability of PRBs and reduce the contact area between the PRB and contaminated groundwater. This study investigated the effect of the initial Cr(VI) concentration ([Cr(VI)init]) in aqueous solutions containing Cl- ions on the generation of H2 gas. ZVI chips were reacted in reactors with 0.5-M NaCl solutions with [Cr(VI)init] ranging between 51 and 303 mg/L. The initial pH was set at 3. The oxidation of ZVI chips by Cr(VI) in aqueous solutions containing Cl- ions produced H2 gas and particles (Fe(III)-Cr(III)(oxy)hydroxides). The Cr(VI) removal from aqueous solutions increased as the [Cr(VI)init] increased, as did H2 gas generation. The positive effect of [Cr(VI)init] on H2 gas generation might be due to an increase in the redox potential gradient as [Cr(VI)init] increases. This increased gradient would enhance H+ ion penetration through the passive film (Fe(III)-Cr(III)(oxy)hydroxides), which formed on the ZVI surface, by diffusion from the solution to pits beneath the passive film.

  9. Removal of chromium (VI) from water using nanoscale zerovalent iron particles supported on herb-residue biochar.

    Science.gov (United States)

    Shang, Jingge; Zong, Mingzhu; Yu, Ying; Kong, Xiangrui; Du, Qiong; Liao, Qianjiahua

    2017-07-15

    A composite material consisting of nanoscale zerovalent iron particles supported on herb-residue biochar (nZVI/BC) was synthesized and used for treatment of Cr(VI)-contaminated water. The effects of initial pH, chromium concentration, contact time, and competition with coexisting anions and natural organic matter (NOM) were also investigated. nZVI/BC was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy analysis (SEM), and the Brunauer-Emmett-Teller surface area was measured. TEM and X-ray photoelectron spectroscopy (XPS) analysis before and after reaction with Cr(VI) showed that reduction and coprecipitation occurred during hexavalent chromium adsorption. The removal of Cr(VI) was highly pH-dependent and the adsorption kinetics data agreed well with the pseudo-second-order model. The presence of SO42- and humic acid promoted Cr(VI) removal at both low and high concentrations, while the HCO3- inhibited the reaction. These results prove that nZVI/BC can be an effective reagent for removal of Cr(VI) from solutions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Monodisperse Iron Oxide Nanoparticles by Thermal Decomposition: Elucidating Particle Formation by Second-Resolved in Situ Small-Angle X-ray Scattering

    Science.gov (United States)

    2017-01-01

    The synthesis of iron oxide nanoparticles (NPs) by thermal decomposition of iron precursors using oleic acid as surfactant has evolved to a state-of-the-art method to produce monodisperse, spherical NPs. The principles behind such monodisperse syntheses are well-known: the key is a separation between burst nucleation and growth phase, whereas the size of the population is set by the precursor-to-surfactant ratio. Here we follow the thermal decomposition of iron pentacarbonyl in the presence of oleic acid via in situ X-ray scattering. This method allows reaction kinetics and precursor states to be followed with high time resolution and statistical significance. Our investigation demonstrates that the final particle size is directly related to a phase of inorganic cluster formation that takes place between precursor decomposition and particle nucleation. The size and concentration of clusters were shown to be dependent on precursor-to-surfactant ratio and heating rate, which in turn led to differences in the onset of nucleation and concentration of nuclei after the burst nucleation phase. This first direct observation of prenucleation formation of inorganic and micellar structures in iron oxide nanoparticle synthesis by thermal decomposition likely has implications for synthesis of other NPs by similar routes. PMID:28572705

  11. A comparison of mutations induced by accelerated iron particles versus those induced by low earth orbit space radiation in the FEM-3 gene of Caenorhabditis elegans

    Science.gov (United States)

    Hartman, P. S.; Hlavacek, A.; Wilde, H.; Lewicki, D.; Schubert, W.; Kern, R. G.; Kazarians, G. A.; Benton, E. V.; Benton, E. R.; Nelson, G. A.

    2001-01-01

    The fem-3 gene of Caenorhabditis elegans was employed to determine the mutation frequency as well as the nature of mutations induced by low earth orbit space radiation ambient to Space Shuttle flight STS-76. Recovered mutations were compared to those induced by accelerated iron ions generated by the AGS synchrotron accelerator at Brookhaven National Laboratory. For logistical reasons, dauer larvae were prepared at TCU, transported to either Kennedy Space Center or Brookhaven National Laboratory, flown in space or irradiated, returned to TCU and screened for mutants. A total of 25 fem-3 mutants were recovered after the shuttle flight and yielded a mutation frequency of 2.1x10(-5), roughly 3.3-fold higher than the spontaneous rate of 6.3x10(-6). Four of the mutations were homozygous inviable, suggesting that they were large deletions encompassing fem-3 as well as neighboring, essential genes. Southern blot analyses revealed that one of the 25 contained a polymorphism in fem-3, further evidence that space radiation can induce deletions. While no polymorphisms were detected among the iron ion-induced mutations, three of the 15 mutants were homozygous inviable, which is in keeping with previous observations that high LET iron particles generate deficiencies. These data provide evidence, albeit indirect, that an important mutagenic component of ambient space radiation is high LET charged particles such as iron ions.

  12. Synthesis and characterization of iron nano particles for the arsenic removal in water; Sintesis y caracterizacion de nanoparticulas de hierro para la remocion de arsenico en agua

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez M, O. E.

    2011-07-01

    The synthesis of iron nanoparticles for the removal of metallic ions in polluted waters has been during the last years study topic for different world organizations. This work presents a synthesis method of conditioned coal with iron nanoparticles starting from the use of leaves of pineapple crown, with the purpose of using it in arsenic removal processes in aqueous phase. For the synthesis of this material, the leaves of the pineapple crown were used like supports structure of the iron nanoparticles. First, the pyrolysis appropriate temperature was determined. For the preparation of the support material, this had contact with a ferric nitrate and hexamine solution, because the preparation of the material and the coal synthesis were realized during the pyrolysis process, where the hexamine molecules and the ferric nitrate react, causing the reduction of the iron particles and their dispersion on the support material, obtaining as product a conditioned coal with iron nanoparticles. For the characterization of the materials were used techniques as: Scanning electron microscopy, Transmission electron microscopy, X-Rays Diffraction), X-Ray photoelectron spectroscopy and Moessbauer spectroscopy; moreover was determined the isoelectric point and the density of surface sites. The arsenic sorption capacity of the materials was evaluated by means of the methodology type lots where was determined the sorption kinetics and isotherms in terms of arsenic concentration and mass. (Author)

  13. Degradation of bisphenol-A by dielectric barrier discharge system: influence of polyethylene glycol stabilized nano zero valent iron particles

    Science.gov (United States)

    Tijani, Jimoh O.; Mouele, Massima E. S.; Fatoba, Ojo O.; Babajide, Omotola O.; Petrik, Leslie F.

    2017-09-01

    In this study we report the synthesis and catalytic properties of polyethylene glycol stabilized nano zero valent iron particles (PEG-nZVI) added to the dielectric barrier discharge (DBD) system to induce photo-Fenton process in the degradation of bisphenol A (BPA) in aqueous solution. The influence of operating parameters such as solution pH, initial concentration of the modelled pollutant and PEG-nZVI dosage on the extent of BPA degradation was investigated. The residual concentration of BPA and its intermediates were determined using high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LCMS). The high resolution scanning electron microscope (HRSEM), x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, and x-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of filamentous, high surface area iron nanoparticles in the zero valent state. The BPA mineralization rate was monitored using total organic carbon (TOC) analyser. 100% BPA removal was achieved with DBD/PEG-nZVI system within 30 min compared to 67.9% (BPA) with DBD alone after 80 min. The complete BPA removal within a short reaction time was attributed to the existence of a synergetic effect in the combined DBD/PEG-nZVI system. Five new transformation products of BPA namely: 4-nitrophenol (C6H5NO3), 4-nitrosophenolate (C6H4NO2), 4-(prop-1-en-2-yl) cyclohexa-3,5-diene-1,2-dione, (C9H8O2), 4-(2-hydroxylpropan-2-yl)cyclohexane-3,5-diene-1,2-dione (C9H10O3), and 1,2-dimethyl-4-(2-nitropropan-2-yl)benzene (C9H10NO4) were identified. BPA degradation proceeded via ozonation, hydroxylation, dimerization, and decarboxylation and nitration step. The combined DBD/photo-Fenton-induced process was found to be the most efficient in the elimination of BPA in aqueous solutions and DBD alone.

  14. Synthesis of green nano iron particles (GnIP) and their application in adsorptive removal of As(III) and As(V) from aqueous solution

    Science.gov (United States)

    Prasad, Kumar Suranjit; Gandhi, Pooja; Selvaraj, Kaliaperumal

    2014-10-01

    The present study reports a new approach to synthesise nano iron particles using leaf extract of Mint (Mentha spicata L.) plant. The synthesised GnIPs were subjected to detailed adsorption studies for removal of arsenite and arsenate from aqueous solution of defined concentration. Iron nanoparticles synthesised using leaf extract showed UV-vis absorption peaks at 360 and 430 nm. TEM result showed the formation of polydispersed nanoparticles of size ranging from 20 to 45 nm. Nanoparticles were found to have core-shell structure. The planer reflection of selected area electron diffraction (SAED) and XRD analysis suggested that iron particles were crystalline and belonged to fcc (face centred cubic) type. Energy-dispersive X-ray analysis (EDAX) shows that Fe was an integral component of synthesised nanoparticles. The content of Fe in nanoparticles was found to be 40%, in addition to other elements like C (16%), O (19%) and Cl (23%). FT-IR study suggested that functional groups like sbnd NH, sbnd Cdbnd O, sbnd Cdbnd N and sbnd Cdbnd C were involved in particle formation. The removal efficiency of GnIP-chitosan composite for As(III) and As(V) was found to be 98.79 and 99.65%. Regeneration of adsorbent suggested that synthesised green GnIP may work as an effective tool for removal of arsenic from contaminated water.

  15. Efficient recovery of nano-sized iron oxide particles from synthetic acid-mine drainage (AMD) water using fuel cell technologies.

    Science.gov (United States)

    Cheng, Shaoan; Jang, Je-Hun; Dempsey, Brian A; Logan, Bruce E

    2011-01-01

    Acid mine drainage (AMD) is an important contributor to surface water pollution due to the release of acid and metals. Fe(II) in AMD reacts with dissolved oxygen to produce iron oxide precipitates, resulting in further acidification, discoloration of stream beds, and sludge deposits in receiving waters. It has recently been shown that new fuel cell technologies, based on microbial fuel cells, can be used to treat AMD and generate electricity. Here we show that this approach can also be used as a technique to generate spherical nano-particles of iron oxide that, upon drying, are transformed to goethite (α-FeOOH). This approach therefore provides a relatively straightforward way to generate a product that has commercial value. Particle diameters ranged from 120 to 700 nm, with sizes that could be controlled by varying the conditions in the fuel cell, especially current density (0.04-0.12 mA/cm(2)), pH (4-7.5), and initial Fe(II) concentration (50-1000 mg/L). The most efficient production of goethite and power occurred with pH = 6.3 and Fe(II) concentrations above 200 mg/L. These results show that fuel cell technologies can not only be used for simultaneous AMD treatment and power generation, but that they can generate useful products such as iron oxide particles having sizes appropriate for used as pigments and other applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. An insight into the metabolic responses of ultra-small superparamagnetic particles of iron oxide using metabonomic analysis of biofluids

    Science.gov (United States)

    Feng, Jianghua; Liu, Huili; Zhang, Limin; Bhakoo, Kishore; Lu, Lehui

    2010-10-01

    Ultra-small superparamagnetic particles of iron oxides (USPIO) have been developed as intravenous organ/tissue-targeted contrast agents to improve magnetic resonance imaging (MRI) in vivo. However, their potential toxicity and effects on metabolism have attracted particular attention. In the present study, uncoated and dextran-coated USPIO were investigated by analyzing both rat urine and plasma metabonomes using high-resolution NMR-based metabonomic analysis in combination with multivariate statistical analysis. The wealth of information gathered on the metabolic profiles from rat urine and plasma has revealed subtle metabolic changes in response to USPIO administration. The metabolic changes include the elevation of urinary α-hydroxy-n-valerate, o- and p-HPA, PAG, nicotinate and hippurate accompanied by decreases in the levels of urinary α-ketoglutarate, succinate, citrate, N-methylnicotinamide, NAG, DMA, allantoin and acetate following USPIO administration. The changes associated with USPIO administration included a gradual increase in plasma glucose, N-acetyl glycoprotein, saturated fatty acid, citrate, succinate, acetate, GPC, ketone bodies (β-hydroxybutyrate, acetone and acetoacetate) and individual amino acids, such as phenylalanine, lysine, isoleucine, glycine, glutamine and glutamate and a gradual decrease of myo-inositol, unsaturated fatty acid and triacylglycerol. Hence USPIO administration effects are reflected in changes in a number of metabolic pathways including energy, lipid, glucose and amino acid metabolism. The size- and surface chemistry-dependent metabolic responses and possible toxicity were observed using NMR analysis of biofluids. These changes may be attributed to the disturbances of hepatic, renal and cardiac functions following USPIO administrations. The potential biotoxicity can be derived from metabonomic analysis and serum biochemistry analysis. Metabonomic strategy offers a promising approach for the detection of subtle

  17. An insight into the metabolic responses of ultra-small superparamagnetic particles of iron oxide using metabonomic analysis of biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jianghua [Department of Physics, Fujian Key Laboratory of Plasma and Magnetic Resonance, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, 361005 (China); Liu Huili; Zhang Limin [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Bhakoo, Kishore [Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A-STAR) 138667 (Singapore); Lu Lehui, E-mail: jianghua.feng@hotmail.com, E-mail: jianghua.feng@wipm.ac.cn [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China)

    2010-10-01

    Ultra-small superparamagnetic particles of iron oxides (USPIO) have been developed as intravenous organ/tissue-targeted contrast agents to improve magnetic resonance imaging (MRI) in vivo. However, their potential toxicity and effects on metabolism have attracted particular attention. In the present study, uncoated and dextran-coated USPIO were investigated by analyzing both rat urine and plasma metabonomes using high-resolution NMR-based metabonomic analysis in combination with multivariate statistical analysis. The wealth of information gathered on the metabolic profiles from rat urine and plasma has revealed subtle metabolic changes in response to USPIO administration. The metabolic changes include the elevation of urinary {alpha}-hydroxy-n-valerate, o- and p-HPA, PAG, nicotinate and hippurate accompanied by decreases in the levels of urinary {alpha}-ketoglutarate, succinate, citrate, N-methylnicotinamide, NAG, DMA, allantoin and acetate following USPIO administration. The changes associated with USPIO administration included a gradual increase in plasma glucose, N-acetyl glycoprotein, saturated fatty acid, citrate, succinate, acetate, GPC, ketone bodies ({beta}-hydroxybutyrate, acetone and acetoacetate) and individual amino acids, such as phenylalanine, lysine, isoleucine, glycine, glutamine and glutamate and a gradual decrease of myo-inositol, unsaturated fatty acid and triacylglycerol. Hence USPIO administration effects are reflected in changes in a number of metabolic pathways including energy, lipid, glucose and amino acid metabolism. The size- and surface chemistry-dependent metabolic responses and possible toxicity were observed using NMR analysis of biofluids. These changes may be attributed to the disturbances of hepatic, renal and cardiac functions following USPIO administrations. The potential biotoxicity can be derived from metabonomic analysis and serum biochemistry analysis. Metabonomic strategy offers a promising approach for the detection of

  18. Asymptomatic and Submicroscopic Carriage of Plasmodium knowlesi Malaria in Household and Community Members of Clinical Cases in Sabah, Malaysia.

    Science.gov (United States)

    Fornace, Kimberly M; Nuin, Nor Afizah; Betson, Martha; Grigg, Matthew J; William, Timothy; Anstey, Nicholas M; Yeo, Tsin W; Cox, Jonathan; Ying, Lau Tiek; Drakeley, Chris J

    2016-03-01

    Although asymptomatic carriage of human malaria species has been widely reported, the extent of asymptomatic, submicroscopic Plasmodium knowlesi parasitemia is unknown. In this study, samples were obtained from individuals residing in households or villages of symptomatic malaria cases with the aim of detecting submicroscopic P. knowlesi in this population. Four published molecular assays were used to confirm the presence of P. knowlesi. Latent class analysis revealed that the estimated proportion of asymptomatic individuals was 6.9% (95% confidence interval, 5.6%-8.4%). This study confirms the presence of a substantial number of asymptomatic monoinfections across all age groups; further work is needed to estimate prevalence in the wider community. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America.

  19. Synthesis of green nano iron particles (GnIP) and their application in adsorptive removal of As(III) and As(V) from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Kumar Suranjit, E-mail: suranjit@gmail.com [Department of Environmental Studies, Faculty of Science, The M. S. University of Baroda, Vadodara, 390002, Gujarat (India); Gandhi, Pooja, E-mail: poojagandhi.3090@gmail.com [Department of Environmental Sciences, Ashok and Rita Patel Institute of Integrated Study and Research in Biotechnology and Allied Sciences (ARIBAS), New Vallabh Vidyanagar, Anand, Gujarat, 388121 (India); Selvaraj, Kaliaperumal, E-mail: k.selvaraj@ncl.res.in [Nano and Computational Materials Lab, Catalysis Division, National Chemical Laboratory, Council of Scientific and Industrial Research, Pune, 411008 (India)

    2014-10-30

    Graphical abstract: - Highlights: • Colloidal GnIP synthesised using extract of Mint leaves were entrapped in chitosan beads. • GnIP loaded beads were employed for removal of As ions, showed excellent removal efficiency. • Iron and chitosan are cost effective materials hence can be a good adsorbent for removal of arsenic. - Abstract: The present study reports a new approach to synthesise nano iron particles using leaf extract of Mint (Mentha spicata L.) plant. The synthesised GnIPs were subjected to detailed adsorption studies for removal of arsenite and arsenate from aqueous solution of defined concentration. Iron nanoparticles synthesised using leaf extract showed UV–vis absorption peaks at 360 and 430 nm. TEM result showed the formation of polydispersed nanoparticles of size ranging from 20 to 45 nm. Nanoparticles were found to have core–shell structure. The planer reflection of selected area electron diffraction (SAED) and XRD analysis suggested that iron particles were crystalline and belonged to fcc (face centred cubic) type. Energy-dispersive X-ray analysis (EDAX) shows that Fe was an integral component of synthesised nanoparticles. The content of Fe in nanoparticles was found to be 40%, in addition to other elements like C (16%), O (19%) and Cl (23%). FT-IR study suggested that functional groups like -NH, -C=O, -C=N and -C=C were involved in particle formation. The removal efficiency of GnIP-chitosan composite for As(III) and As(V) was found to be 98.79 and 99.65%. Regeneration of adsorbent suggested that synthesised green GnIP may work as an effective tool for removal of arsenic from contaminated water.

  20. Use of CAH-degrading bacteria as test-organisms for evaluating the impact of fine zerovalent iron particles on the anaerobic subsurface environment.

    Science.gov (United States)

    Velimirovic, Milica; Simons, Queenie; Bastiaens, Leen

    2015-09-01

    The release of fine zerovalent iron (ZVI) particles in the environment after being introduced for in-situ treatment of compounds like chlorinated aliphatic hydrocarbons (CAHs) may raise questions toward environmental safety, especially for nanoscale materials. Classical single-species ecotoxicity tests do focus on aerobic conditions and are only relevant for the scenario when ZVI-particles reach surface water. Herein, we present an alternative approach where a CAH-degrading mixed bacterial culture was used as test-organisms relevant for the anaerobic subsurface. The impact of different ZVI particles on the bacterial culture was evaluated mainly by quantifying ATP, a reporter molecule giving a general indication of the microbial activity. These lab-scale batch tests were performed in liquid medium, without protecting and buffering aquifer material, as such representing worst-case scenario. The activity of the bacterial culture was negatively influenced by nanoscale zerovalent iron at doses as low as 0.05 g L(-1). On the other hand, concentrations up to 2 g L(-1) of several different types of microscale zerovalent iron (mZVI) particles stimulated the activity. However, very high doses of 15-30 g L(-1) of mZVI showed an inhibiting effect on the bacterial community. Negative effects of ZVIs were confirmed by H2 accumulation in the batch reactors and the absence of lactate consumption. Observed inhibition also corresponded to a pH increase above 7.5, explicable by ZVI corrosion that was found to be dose-dependent. The obtained results suggest that low doses of mZVIs will not show severe inhibition effects on the microbial community once used for in-situ treatment of CAHs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Magnetic Particle Spectroscopy Reveals Dynamic Changes in the Magnetic Behavior of Very Small Superparamagnetic Iron Oxide Nanoparticles During Cellular Uptake and Enables Determination of Cell-Labeling Efficacy.

    Science.gov (United States)

    Poller, Wolfram C; Löwa, Norbert; Wiekhorst, Frank; Taupitz, Matthias; Wagner, Susanne; Möller, Konstantin; Baumann, Gert; Stangl, Verena; Trahms, Lutz; Ludwig, Antje

    2016-02-01

    In vivo tracking of nanoparticle-labeled cells by magnetic resonance imaging (MRI) crucially depends on accurate determination of cell-labeling efficacy prior to transplantation. Here, we analyzed the feasibility and accuracy of magnetic particle spectroscopy (MPS) for estimation of cell-labeling efficacy in living THP-1 cells incubated with very small superparamagnetic iron oxide nanoparticles (VSOP). Cell viability and proliferation capacity were not affected by the MPS measurement procedure. In VSOP samples without cell contact, MPS enabled highly accurate quantification. In contrast, MPS constantly overestimated the amount of cell associated and internalized VSOP. Analyses of the MPS spectrum shape expressed as harmonic ratio A₅/A₃ revealed distinct changes in the magnetic behavior of VSOP in response to cellular uptake. These changes were proportional to the deviation between MPS and actual iron amount, therefore allowing for adjusted iron quantification. Transmission electron microscopy provided visual evidence that changes in the magnetic properties correlated with cell surface interaction of VSOP as well as with alterations of particle structure and arrangement during the phagocytic process. Altogether, A₅/A₃-adjusted MPS enables highly accurate, cell-preserving VSOP quantification and furthermore provides information on the magnetic characteristics of internalized VSOP.

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

    Science.gov (United States)

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

    2017-10-05

    The photo-Fenton process is recognized as a promising technique towards microorganism disinfection in wastewater, but its efficiency is hampered at near-neutral pH operating values. In this work, we overcome these obstacles by using the heterogeneous photo-Fenton process as the default disinfecting technique, targeting MS2 coliphage in wastewater. The use of low concentrations of iron oxides in wastewater without H2O2 (wüstite, maghemite, magnetite) has demonstrated limited semiconductor-mediated MS2 inactivation. Changing the operational pH and the size of the oxide particles indicated that the isoelectric point of the iron oxides and the active surface area are crucial in the success of the process, and the possible underlying mechanisms are investigated. Furthermore, the addition of low amounts of Fe-oxides (1mgL-1) and H2O2 in the system (1, 5 and 10mgL-1) greatly enhanced the inactivation process, leading to heterogeneous photo-Fenton processes on the surface of the magnetically separable oxides used. Additionally, photo-dissolution of iron in the bulk, lead to homogeneous photo-Fenton, further aided by the complexation by the dissolved organic matter in the solution. Finally, we assess the impact of the presence of the bacterial host and the difference caused by the different iron sources (salts, oxides) and the Fe-oxide size (normal, nano-sized). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Electric arc furnace dust utilization in iron ore sintering: influence of particle size; Utilizacao da poeira de aciaria eletrica na sinterizacao de minerio de ferro: influencia da granulometria

    Energy Technology Data Exchange (ETDEWEB)

    Telles, V.B.; Junca, E.; Rodrigues, G.F.; Espinosa, D.C.R.; Tenorio, J.A.S., E-mail: victor_bridit@hotmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    The aim of this work was to study the utilization of electric arc furnace dust (EAFD) generated in steelmaking by electric arc furnace (EAF) as raw material in iron ore sintering. The waste was characterized by size, chemical composition and X-ray diffraction. The physical characterization showed that 90% of the particles have a size less then 1,78 {mu}m and the material have the tendency to agglomerate. The waste were submitted to a pre-agglomeration prior to its incorporation in the sinter. The influence on the addition of the waste with different granulometry in the iron or sinter production were analyzed by sinter characterization and sintering parameters. (author)

  4. Submicroscopic deletions at the WAGR locus, revealed by nonradioactive in situ hybridization

    Energy Technology Data Exchange (ETDEWEB)

    Fantes, J.A.; Bickmore, W.A.; Fletcher, J.M.; Hanson, I.M.; Heyningen, V. van (Western General Hospital, Edinburgh (United Kingdom)); Ballesta, F. (Hospital Clinic 1, Barcelona (Spain))

    1992-12-01

    Fluorescence in situ hybridization (FISH) with biotin-labeled probes mapping to 11p13 has been used for the molecular analysis of deletions of the WAGR (Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation) locus. They have detected a submicroscopic 11p13 deletion in a child with inherited aniridia who subsequently presented with Wilms tumor in a horseshoe kidney, only revealed at surgery. The mother, who has aniridia, was also found to carry a deletion including both the aniridia candidate gene (AN2) and the Wilms tumor predisposition gene (WT1). This is therefore a rare case of an inherited WAGR deletion. Wilms tumor has so far only been associated with sporadic de novo aniridia cases. The authors have shown that a cosmid probe for a candidate aniridia gene, homologous to the mouse Pax-6 gene, is deleted in cell lines from aniridia patients with previously characterized deletions at 11p13, while another cosmid marker mapping between two aniridia-associated translocation breakpoints (and hence a second candidate marker) is present on both chromosomes. These results support the Pax-6 homologue as a strong candidate for the AN2 gene. FISH with cosmid probes has proved to be a fast and reliable technique for the molecular analysis of deletions. It can be used with limited amounts of material and has strong potential for clinical applications. 41 refs., 1 figs., 3 tabs.

  5. Obtaining of iron particles of nanometer size in a natural zeolite; Obtencion de particulas de hierro de tamano nanometrico en una zeolita natural

    Energy Technology Data Exchange (ETDEWEB)

    Xingu C, E. G.

    2013-07-01

    The zeolites are aluminosilicates with cavities that can act as molecular sieve. Their crystalline structure is formed by tetrahedrons that get together giving place to a three-dimensional net, in which each oxygen is shared by two silicon atoms, being this way part of the tecto silicate minerals, its external and internal areas reach the hundred square meters for gram, they are located in a natural way in a large part of earth crust and also exist in a synthetic way. In Mexico there are different locations of zeolitic material whose important component is the clinoptilolite. In this work the results of three zeolitic materials coming from San Luis Potosi are shown, the samples were milled and sieved for its initial characterization, to know its chemical composition, crystalline phases, morphology, topology and thermal behavior before and after its homo-ionization with sodium chloride, its use as support of iron particles of nanometer size. The description of the synthesis of iron particles of nanometer size is also presented, as well as the comparison with the particles of nanometer size synthesized without support after its characterization. The characterization techniques used during the experimental work were: Scanning electron microscopy, X-ray diffraction, Infrared spectroscopy, specific area by means of BET and thermogravimetry analysis. (Author)

  6. Effect of injection velocity and particle concentration on transport of nanoscale zero-valent iron and hydraulic conductivity in saturated porous media.

    Science.gov (United States)

    Strutz, Tessa J; Hornbruch, Götz; Dahmke, Andreas; Köber, Ralf

    2016-08-01

    Successful groundwater remediation by injecting nanoscale zero-valent iron (NZVI) particles requires efficient particle transportation and distribution in the subsurface. This study focused on the influence of injection velocity and particle concentration on the spatial NZVI particle distribution, the deposition processes and on quantifying the induced decrease in hydraulic conductivity (K) as a result of particle retention by lab tests and numerical simulations. Horizontal column tests of 2m length were performed with initial Darcy injection velocities (q0) of 0.5, 1.5, and 4.1m/h and elemental iron input concentrations (Fe(0)in) of 0.6, 10, and 17g/L. Concentrations of Fe(0) in the sand were determined by magnetic susceptibility scans, which provide detailed Fe(0) distribution profiles along the column. NZVI particles were transported farther at higher injection velocity and higher input concentrations. K decreased by one order of magnitude during injection in all experiments, with a stronger decrease after reaching Fe(0) concentrations of about 14-18g/kg(sand). To simulate the observed nanoparticle transport behavior the existing finite-element code OGS has been successfully extended and parameterized for the investigated experiments using blocking, ripening, and straining as governing deposition processes. Considering parameter relationships deduced from single simulations for each experiment (e.g. deposition rate constants as a function of flow velocity) one mean parameter set has been generated reproducing the observations in an adequate way for most cases of the investigated realistic injection conditions. An assessment of the deposition processes related to clogging effects showed that the percentage of retention due to straining and ripening increased during experimental run time resulting in an ongoing reduction of K. Clogging is mainly evoked by straining which dominates particle deposition at higher flow velocities, while blocking and ripening play a

  7. Remediation of Chlorpyrifos-Contaminated Soils by Laboratory-Synthesized Zero-Valent Nano Iron Particles: Effect of pH and Aluminium Salts

    Directory of Open Access Journals (Sweden)

    A. Vijaya Bhaskar Reddy

    2013-01-01

    Full Text Available Degradation of the insecticide chlorpyrifos in contaminated soils was investigated using laboratory synthesized zero-valent nano iron (ZVNI particles. The synthesized ZVNI particles were characterized as nanoscale sized by scanning electron microscopy (SEM and transmission electron microscopy (TEM. The zero-valent state (Fe0 of iron was confirmed by EDAX analysis and the morphology of the ZVNI particles was studied by XRD. Batch experiments were conducted by treating the chlorpyrifos contaminated soil with ZVNI, our results indicate that 90% of chlorpyrifos was degraded after 10 days of incubation. Only 32% degradation was observed with micro zero-valent iron (mZVI and no considerable degradation was attained without ZVNI. The degradation of chlorpyrifos followed the first-order kinetics with a rate constant and a half-life of 0.245 day−1 and 2.82 days, respectively. Degradation was monitored at two different pH values, that is, pH 10 and pH 4. Chlorpyrifos degradation rate constant increased as the pH decreases from 10 to 4. The corresponding rate constant and half-lives were 0.43 day−1 and 1.57days for pH 4, 0.18 day−1 and 3.65 days for pH 10. In addition, an attempt was made by augmenting Al2(SO43 with ZVNI and it was found that the degradation rate of chlorpyrifos was greatly enhanced and the rate constant was rapidly increased from 0.245 day−1 to 0.60 day−1. Hydrolysis and stepwise dechlorination pathway of chlorpyrifos with ZVNI was the dominant reaction.

  8. Effect of particle size on dc conductivity, activation energy and diffusion coefficient of lithium iron phosphate in Li-ion cells

    Directory of Open Access Journals (Sweden)

    T.V.S.L. Satyavani

    2016-03-01

    Full Text Available Cathode materials in nano size improve the performance of batteries due to the increased reaction rate and short diffusion lengths. Lithium Iron Phosphate (LiFePO4 is a promising cathode material for Li-ion batteries. However, it has its own limitations such as low conductivity and low diffusion coefficient which lead to high impedance due to which its application is restricted in batteries. In the present work, increase of conductivity with decreasing particle size of LiFePO4/C is studied. Also, the dependence of conductivity and activation energy for hopping of small polaron in LiFePO4/C on variation of particle size is investigated. The micro sized cathode material is ball milled for different durations to reduce the particle size to nano level. The material is characterized for its structure and particle size. The resistivities/dc conductivities of the pellets are measured using four probe technique at different temperatures, up to 150 °C. The activation energies corresponding to different particle sizes are calculated using Arrhenius equation. CR2032 cells are fabricated and electrochemical characteristics, namely, ac impedance and diffusion coefficients, are studied.

  9. Nanoscale zero-valent iron particles supported on reduced graphene oxides by using a plasma technique and their application for removal of heavy-metal ions.

    Science.gov (United States)

    Li, Jie; Chen, Changlun; Zhang, Rui; Wang, Xiangke

    2015-06-01

    Nanoscale zero-valent iron particles supported on reduced graphene oxides (NZVI/rGOs) from spent graphene oxide (GO)-bound iron ions were developed by using a hydrogen/argon plasma reduction method to improve the reactivity and stability of NZVI. The NZVI/rGOs exhibited excellent water treatment performance with excellent removal capacities of 187.16 and 396.37 mg g(-1) for chromium and lead, respectively. Moreover, the NZVI/rGOs could be regenerated by plasma treatment and maintained high removal ability after four cycles. X-ray photoelectron spectroscopy analysis results implied that the removal mechanisms could be attributed to adsorption/precipitation, reduction, or both. Such multiple removal mechanisms by the NZVI/rGOs were attributed to the reduction ability of the NZVI particles and the role of dispersing and stabilizing abilities of the rGOs. The results indicated that the NZVI/rGOs prepared by a hydrogen/argon plasma reduction method might be an effective composite for heavy-metal-ion removal. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Multi-scale three-dimensional characterization of iron particles in dusty olivine: Implications for paleomagnetism of chondritic meteorites

    DEFF Research Database (Denmark)

    Einsle, Joshua F.; Harrison, Richard J.; Kasama, Takeshi

    2016-01-01

    Dusty olivine (olivine containing multiple sub-micrometer inclusions of metallic iron) in chondritic meteorites is considered an ideal carrier of paleomagnetic remanence, capable of maintaining a faithful record of pre-accretionary magnetization acquired during chondrule formation. Here we show how...

  11. Complement facilitates macrophage phagocytosis of inhaled iron particles but has little effect in mediating silica-induced lung inflammatory and clearance responses

    Energy Technology Data Exchange (ETDEWEB)

    Warheit, D.B.; Carakostas, M.C.; Bamberger, J.R.; Hartsky, M.A. (E.I. de Pont de Nemours and Co., Newark, DE (United States))

    1991-12-01

    The present studies were undertaken to investigate the role of complement in mediating pulmonary inflammation and/or phagocytosis as a function of particle clearance in rats exposed to silica or carbonyl iron (CI) particles. Both particle types were shown to be weak activators of serum complement in vitro. In these studies, normal and complement-depressed (CVFD-treated) rats were exposed to aerosols of Ci or silica particles for 6 hr at 100 mg/m{sup 3}. Following exposure, alveolar fluids and cells from sham and dust-exposed animals were recovered by bronchoalveolar lavage (BAL) at several time periods postexposure and measured for a variety of biochemical and cellular indices. In addition, pulmonary macrophages were cultured and studied for morphology and phagocytosis. The authors results showed that CI exposure did not produce cellular or biochemical indices of pulmonary inflammation, either in normal or complement-depleted rats. However, fewer phagocytic macrophages were recovered from the lungs of CVF-treated, CI-exposed rats than from normal exposed animals. In contrast, silica inhalation produced a sustained PMN inflammatory response in the lungs of exposed rats, measured up through 1 month postexposure, along with significant increases in BAL fluid levels of LDH, protein, and alkaline phosphatase and deficits in pulmonary macrophage phagocytic functions.

  12. Histological and submicroscopical findings on the seminiferous parenchyma in rams after copper oxide intoxication from industrial emissions.

    Science.gov (United States)

    Vrzgulová, M

    1993-01-01

    In this work the author examined the histological and submicroscopical picture of the seminiferous parenchyma in 5 breeding rams from a herd in which intoxication with copper oxide from industrial emissions of a copper producing plant had been diagnosed. The toxic effect irreversibly damages all developmental stages of the germ cells. It injures the cell membranes of both germ cells and Sertoli cells. Similar changes were observed on the interstitial cells. The degree of injury to the germinative epithelium confirms its significant role in the decreased reproduction rate of the herd under examination.

  13. Numerical simulation on magnetic assembled structures of iron-based metallic particles within MMCs by a homogeneous strong magnetic field

    Science.gov (United States)

    Liu, Chunwei; Sun, Zhi; Zheng, Lichun; Huang, Shuigen; Blanpain, Bart; Guo, Muxing

    2015-09-01

    Particle-reinforced metal matrix composites (MMCs) have excellent physicochemical properties as structural materials. The morphology and distribution control of reinforcement particles during the fabrication of MMCs are difficult-but-critical-to-achieve required properties of the materials. This research demonstrates a possibility to quantitatively control the distribution of particles in the metal matrix by applying a magnetic field. A 2D numerical model is developed and applied to evaluate the behaviour of Fe-based metallic particles in aluminum MMCs. By combination of 2D simulation with intersectional directions, this model also provides some hints for 3D practice. The assembled structure is found to be governed by the external magnetic field orientation, magnetic flux density and magnetic susceptibility of the particles. Both behaviours of particle agglomeration and dispersion are quantitatively characterized in different conditions. By using a strong magnetic field, it is found that assembled structures of weakly magnetic particles can be effectively manipulated. Therefore, it can be expected to fabricate particle-enhanced metal matrix composites/ceramics/glass with substantial improvements in physical and chemical properties by using a magnetic field.

  14. Neutron and Charged-Particle Induced Cross Sections for Radiochemistry for Isotopes of Scandium, Titanium, Vanadium, Chromium, Manganese, and Iron

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, K; Hoffman, R D; Dietrich, F S; Bauer, R; Mustafa, M

    2004-11-30

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Local systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron and proton induced nuclear reaction cross sections in the mass region of scandium, titanium, vanadium, chromium, manganese, and iron (21 {le} Z {le} 26, 20 {le} N {le} 32).

  15. Association of sub-microscopic malaria parasite carriage with transmission intensity in north-eastern Tanzania

    Directory of Open Access Journals (Sweden)

    Manjurano Alphaxard

    2011-12-01

    Full Text Available Abstract Background In malaria endemic areas, individuals are frequently asymptomatic and may be undetected by conventional microscopy or newer, rapid diagnostic tests. Molecular techniques allow a more accurate assessment of this asymptomatic parasite burden, the extent of which is important for malaria control. This study examines the relative prevalence of sub-microscopic level parasite carriage and clonal complexity of infections (multiplicity of infection over a range of endemicities in a region of north-eastern Tanzania where altitude is an established proxy of malaria transmission. The PCR prevalence was then compared against other measures of transmission intensity collected in the same area. Methods This study used 1,121 blood samples collected from a previously conducted cross-sectional malario-metric survey during the short rainy season in 2001 from 13 villages (three at 1,200 m in altitude above sea level. Samples were analysed by PCR for carriage of parasites and multiplicity of infection. These data were compared with other measures of transmission intensity collected from the same area. Results Parasite prevalence was 34.7% by PCR and 13.6% by microscopy; a 2.5-fold difference in line with other recent observations. This fold difference was relatively consistent at the different altitude bands despite a marked decrease in parasite prevalence with altitude: vs 28.6, 600-1,200 m 35.5 vs 9.9, > 1,200 m 15.8 vs 5.9. The difference between parasite prevalence by PCR was 3.2 in individuals aged between 15 and 45 years (34.5 vs 10.9 compared with 2.5 in those aged 1-5 (34.0 vs 13.5 though this was not statistically significant. Multiplicity of infection (MOI ranged from 1.2 to 3.7 and was positively associated with parasite prevalence assessed by both PCR and microscopy. There was no association of MOI and age. Village level PCR parasite prevalence was strongly correlated with altitude, sero-conversion rate and predicted entomological

  16. Malaria elimination challenges in Mesoamerica: evidence of submicroscopic malaria reservoirs in Guatemala.

    Science.gov (United States)

    Lennon, Shirley Evelyn; Miranda, Adolfo; Henao, Juliana; Vallejo, Andres F; Perez, Julianh; Alvarez, Alvaro; Arévalo-Herrera, Myriam; Herrera, Sócrates

    2016-08-30

    Even though malaria incidence has decreased substantially in Guatemala since 2000, Guatemala remains one of the countries with the highest malaria transmission in Mesoamerica. Guatemala is committed to eliminating malaria as part of the initiative 'Elimination of Malaria in Mesoamerica and the Island of Hispaniola' (EMMIE); however, it is still in the control phase. During the past decade, the government strengthened malaria control activities including mass distribution of long-lasting insecticide-impregnated bed nets, early diagnosis and prompt treatment. This study aimed to determine the prevalence of malaria, including gametocytes, in three areas of Guatemala using active case detection (ACD) and quantitative polymerase chain reaction (qPCR). Cross-sectional surveys were conducted in three departments with varying transmission intensities: Escuintla, Alta Verapaz and Zacapa. Blood samples from 706 volunteers were screened for malaria using microscopy and qPCR which was also used to determine the prevalence of gametocytes among infected individuals. Results were collected and analysed using REDCap and R Project, respectively. Malaria was diagnosed by microscopy in only 2.8 % (4/141) of the volunteers from Escuintla. By contrast, qPCR detected a prevalence of 7.1 % (10/141) in the same volunteers, 8.4 % (36/429) in Alta Verapaz, and 5.9 % (8/136) in Zacapa. Overall, 7.6 % (54/706) of the screened individuals were positive, with an average parasitaemia level of 40.2 parasites/μL (range 1-1133 parasites/μL) and 27.8 % carried mature gametocytes. Fifty-seven percent (31/54) of qPCR positive volunteers were asymptomatic and out of the 42.6 % of symptomatic individuals, only one had a positive microscopy result. This study found a considerable number of asymptomatic P. vivax infections that were mostly submicroscopic, of which, approximately one-quarter harboured mature gametocytes. This pattern is likely to contribute to maintaining transmission across the

  17. The effect of particle size of iron powder on {alpha} to {gamma} transformation in the nanostructured high nitrogen Fe-Cr-Mn-Mo stainless steel produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Tehrani, F.; Abbasi, M.H. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Golozar, M.A., E-mail: golozar@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Panjepour, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-05-15

    Research highlights: {yields} High nitrogen austenitic Fe18Cr10Mn4Mo stainless steel can be produced by MA and without annealing. {yields} The initial powder particle size plays an important role on the rate of nitrogen absorption and consequently on phase transformation kinetics. {yields} Nitrogen content in the steel is the most effective parameter for {alpha} to {gamma} kinetic enhancement. - Abstract: In this study, the effect of particle size of iron powder on {alpha} to {gamma} transformation in the nanostructured high nitrogen Fe-18Cr-10Mn-4Mo stainless steel, produced by mechanical alloying (MA) was investigated. For this purpose iron powders with two different particle sizes were used. MA was performed under nitrogen atmosphere, using a high-energy planetary ball mill. X-ray diffraction (XRD) patterns and nitrogen analysis revealed that by decreasing the iron mean particle size, a higher transformation rate is obtained due to increase in the rate of nitrogen absorption. Moreover, nitrogen solubility in both milled samples was increased noticeably by increasing the milling time. This is believed to be due to the increase of lattice defects and development of nanostructure through MA. Variations of grain size and internal lattice strain versus milling time, for both iron particle sizes, showed that the critical ferrite grain size for austenite nucleation is less than 10 nm.

  18. Respiratory Effects of Inhaled Single-Walled Carbon Nanotubes: The Role of Particle Morphology and Iron Content

    Science.gov (United States)

    Madl, Amy Kathleen

    Nanotechnology provides promise for significant advancements in a number of different fields including imaging, electronics, and therapeutics. With worldwide production of carbon nanotubes (CNTs) exceeding over 500 metric tons annually and industry growth expecting to double over the next 5 yr, there are concerns our understanding of the hazards of these nanomaterials may not be keeping pace with market demand. The physicochemical properties of CNTs may delineate the key features that determine either toxicity or biocompatibility and assist in evaluating the potential health risks posed in industrial and consumer product settings. We hypothesized that the iron content and morphology of inhaled single-walled carbon nanotubes (SWCNTs) influences the extent of cellular injury and alters homeostasis in the lung. To address this hypothesis, (1) an aerosol system was developed to deliver carbon-based nanomaterials in a manner of exposure that is physiologically and environmentally relevant (e.g., inhalation), (2) acute (1 d) and subacute (10 d) nose-only inhalation studies to a well-characterized aerosol of iron-containing (FeSWCNT) versus cleaned (iron removed, cSWCNTs) SWCNTs were conducted to evaluate the time-course patterns of possible injury through measurement of markers of cytotoxicity, inflammation, and cellular remodeling/homeostasis, and (3) the effects of SWCNTs were compared to other well-studied materials (e.g. non-fibrous, low-iron content ultrafine carbon black and fibrous, high-iron content, highly persistent, durable and potent carcinogen crocidolite) to offer insights into the relative toxicity of these nanomaterials as well as the possible mechanisms by which the effects occur. Rats (SD) were exposed to either aerosolized SWCNTs (raw FeSWCNT or purified cSWCNT), carbon black (CB), crocidolite, or fresh air via nose-only inhalation. Markers of inflammation and cytotoxicity in lung lavage, mucin in different airway generations, and collagen in the

  19. Gas-phase and particle-phase PCDD/F congener distributions in the flue gas from an iron ore sintering plant.

    Science.gov (United States)

    Liu, Xiaolong; Ye, Meng; Wang, Xue; Liu, Wen; Zhu, Tingyu

    2017-04-01

    The activated carbon injection-circulating fluidized bed (ACI-CFB)-bag filter coupling technique was studied in an iron ore sintering plant. For comparison, the removal efficiencies under the conditions without or with ACI technology were both evaluated. It was found that the polychlorinated dibenzo-p-dioxins and dibenzofuran (PCDD/F) removal efficiency for total international toxic equivalence quantity (I-TEQ) concentration was improved from 91.61% to 97.36% when ACI was employed, revealing that ACI was very conducive to further controlling the PCDD/F emissions. Detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the Inlet and Outlet samples were determined. Additionally, the PCDD/F distribution for the Fly ash-with ACI sample of was also studied. Copyright © 2016. Published by Elsevier B.V.

  20. Cryopreservation of embryonic stem cell-derived multicellular neural aggregates labeled with micron-sized particles of iron oxide for magnetic resonance imaging.

    Science.gov (United States)

    Yan, Yuanwei; Sart, Sébastien; Calixto Bejarano, Fabian; Muroski, Megan E; Strouse, Geoffrey F; Grant, Samuel C; Li, Yan

    2015-01-01

    Magnetic resonance imaging (MRI) provides an effective approach to track labeled pluripotent stem cell (PSC)-derived neural progenitor cells (NPCs) for neurological disorder treatments after cell labeling with a contrast agent, such as an iron oxide derivative. Cryopreservation of pre-labeled neural cells, especially in three-dimensional (3D) structure, can provide a uniform cell population and preserve the stem cell niche for the subsequent applications. In this study, the effects of cryopreservation on PSC-derived multicellular NPC aggregates labeled with micron-sized particles of iron oxide (MPIO) were investigated. These NPC aggregates were labeled prior to cryopreservation because labeling thawed cells can be limited by inefficient intracellular uptake, variations in labeling efficiency, and increased culture time before use, minimizing their translation to clinical settings. The results indicated that intracellular MPIO incorporation was retained after cryopreservation (70-80% labeling efficiency), and MPIO labeling had little adverse effects on cell recovery, proliferation, cytotoxicity and neural lineage commitment post-cryopreservation. MRI analysis showed comparable detectability for the MPIO-labeled cells before and after cryopreservation indicated by T2 and T2* relaxation rates. Cryopreserving MPIO-labeled 3D multicellular NPC aggregates can be applied in in vivo cell tracking studies and lead to more rapid translation from preservation to clinical implementation. © 2015 American Institute of Chemical Engineers.

  1. Single-particle chemical characterization and source apportionment of iron-containing atmospheric aerosols in Asian outflow

    Science.gov (United States)

    Furutani, Hiroshi; Jung, Jinyoung; Miura, Kazuhiko; Takami, Akinori; Kato, Shungo; Kajii, Yoshizumi; Uematsu, Mitsuo

    2011-09-01

    Using a single-particle mass spectrometer, the size and chemical composition of individual Fe-containing atmospheric aerosols (Fe aerosols) with diameter from 100 to 1800 nm were characterized during Asian outflow season (spring of 2008) in Okinawa Island, Japan and their sources were determined. Fe aerosols were classified into five unique particle types which were mixed with specific compound(s) and related to their sources (crustal, fly ash/K-biomass burning, elemental carbon, metals, and vanadium). Particle number-based contribution of the crustal particle type, which has been thought to be the main source of aerosol Fe, was quite small (2 ˜ 10%) in all size ranges, while anthropogenic Fe aerosols were the dominant contributor in this study. Fly ash/K-biomass burning type was the most abundant particle types, which contributed ˜50%. Metals and elemental carbon types contributed ˜20% and ˜10%, respectively. Contribution of vanadium type was variable (5 ˜ 50%), which is attributed to ship emission. The frequent appearance of lithium ion peak in the fly ash/K-biomass burning type strongly suggests that large fraction of the type is coal combustion origin, reflecting high coal usage in China. These results show that anthropogenic sources contributes significant portion of Fe aerosols in Asian outflow. Excluding the vanadium type, relative contribution of the remaining four particle types was constant over the course of study, which remained even when the total concentration of Fe aerosols changed and fraction of the Fe aerosols among atmospheric aerosols decreased significantly by the switch of air mass type into marine type. We concluded that the observed constant relative abundance reflected the relative source strength of Fe aerosols in Asian outflow, particularly emphasizing the importance of coal combustion source in East Asia.

  2. Arsenic Removal from Water Using Various Adsorbents: Magnetic Ion Exchange Resins, Hydrous Ion Oxide Particles, Granular Ferric Hydroxide, Activated Alumina, Sulfur Modified Iron, and Iron Oxide-Coated Microsand

    KAUST Repository

    Sinha, Shahnawaz

    2011-09-30

    The equilibrium and kinetic adsorption of arsenic on six different adsorbents were investigated with one synthetic and four natural types (two surface and two ground) of water. The adsorbents tested included magnetic ion exchange resins (MIEX), hydrous ion oxide particles (HIOPs), granular ferric hydroxide (GFH), activated alumina (AA), sulfur modified iron (SMI), and iron oxide-coated mic - rosand (IOC-M), which have different physicochemical properties (shape, charge, surface area, size, and metal content). The results showed that adsorption equilibriums were achieved within a contact period of 20 min. The optimal doses of adsorbents determined for a given equilibrium concentration of C eq = 10 μg/L were 500 mg/L for AA and GFH, 520–1,300 mg/L for MIEX, 1,200 mg/L for HIOPs, 2,500 mg/L for SMI, and 7,500 mg/L for IOC-M at a contact time of 60 min. At these optimal doses, the rate constants of the adsorbents were 3.9, 2.6, 2.5, 1.9, 1.8, and 1.6 1/hr for HIOPs, AA, GFH, MIEX, SMI, and IOC-M, respectively. The presence of silicate significantly reduced the arsenic removal efficiency of HIOPs, AA, and GFH, presumably due to the decrease in chemical binding affinity of arsenic in the presence of silicate. Additional experiments with natural types of water showed that, with the exception of IOC-M, the adsorbents had lower adsorption capacities in ground water than with surface and deionized water, in which the adsorption capacities decreased by approximately 60–95 % .

  3. Iron Chelation

    Science.gov (United States)

    Skip to main content Menu Donate Treatments Therapies Iron Chelation Iron chelation therapy is the main treatment ... have iron overload and need treatment. What is iron overload? Iron chelation therapy is used when you ...

  4. Prader-Willi syndrome and atypical submicroscopic 15q11-q13 deletions with or without imprinting defects.

    Science.gov (United States)

    Hassan, Maaz; Butler, Merlin G

    2016-11-01

    We report a 20 year follow up on a Caucasian female, now 26 years of age, with Prader-Willi syndrome (PWS) harboring an atypical 15q11-q13 submicroscopic deletion of 100-200 kb in size first detected in 1996 involving the imprinting center, SNRPN gene and surrounding region. PWS is a rare complex disorder caused by the loss of paternally expressed genes in the 15q11-q13 region. With high resolution chromosomal microarray and methylation - specific MLPA analysis, we updated the genetic findings on our patient and found a 209,819bp deletion including the SNURF-SNRPN gene complex which includes the imprinting center and the SNORD116 region. We compared with four other similarly reported individuals in the literature with atypical submicroscopic deletions within this region but without imprinting center involvement to better characterize the specific genetic lesions causing PWS clinical findings. Clinically, our patient met the diagnostic criteria of PWS including infantile hypotonia, a poor suck with feeding difficulties, global developmental delays and later food foraging, childhood obesity, small hands and skin picking. Small atypical deletions of comparable sizes were seen in the 15q11-q13 region in all five cases and similar behavioral/physical characteristics were found despite an imprinting defect in our patient. These results further support an overlapping critical deletion region involving the non-coding snoRNA SNORD116 in common in the five individuals playing a key role in contributing to the PWS phenotype. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Accelerated heavy particles and the lens. VII: The cataractogenic potential of 450 MeV/amu iron ions

    Science.gov (United States)

    Worgul, B. V.; Brenner, D. J.; Medvedovsky, C.; Merriam, G. R. Jr; Huang, Y.

    1993-01-01

    PURPOSE. To determine the cataractogenic potential dose of high velocity iron ions as a fixation of dose administered singly or fractionated. The dose is critical to risk assessment and to theories of radiation action and cataractogenesis. METHODS. Twenty-eight-day-old rats were examined by slit-lamp biomicroscopy on a weekly-bi-weekly basis for more than 2 yr after radiation exposure. For the acute exposure study doses of 1, 2, 5, 25, and 50 cGy were evaluated. The fractionated regimens involved total doses of 2, 25, and 50 cGy. The reference radiation consisted of 50, 100, 200, or 700 cGy of 250 kilovolt (peak) x-rays. RESULTS. In accordance with previous findings in the rat using 570 MeV/amu 40Ar ions, the relative biologic effectiveness increased rapidly with decreasing dose, reaching values as high as 100. Unlike 40Ar ions, fractionation of the 56Fe doses did not produce a consistent enhancement at any of the doses examined. CONCLUSIONS. The data support the previous findings of a high cataractogenic potential for high linear energy transfer (LET) radiation. The effectiveness for the production of cataracts increases with decreasing dose relative to x-rays and is independent of dose protraction. Although the present study did not reveal a consistent enhancement of effect when the ions were applied in fractions, the results are consistent with at least one theory of the inverse dose-rate effect observed for high-LET radiation.

  6. [Effects of particle size of zero-valent iron on the reactivity of activating persulfate and kinetics for the degradation of acid orange 7].

    Science.gov (United States)

    Li, Huan-xuan; Wan, Jin-quan; Ma, Yong-wen; Huang, Ming-zhiz; Wang, Yan; Chen Yang, Mei

    2014-09-01

    This research described the heterogeneous reactions of persulfate with different particle sizes of zero-valent iron (including 1 mm-ZVI,150 μm-ZVI,50 nm-ZVI) for degradation of acid orange 7(AO7) , and studied the kinetics and intermediate products of AO7 under these systems. The results demonstrated that these three types of ZVI were efficient in promoting the degradation of AO7, the degradation efficiencies of AO7 were 43% , 97% , and 100% within 90 min respectively, in the 1 mm-ZVI,150 μm-ZVI and 50 nm- ZVI systems, respectively. With the results of kinetic fitting models, the pseudo first-order kinetics exhibited better fitting results in the 1 mm-ZVI,150 μm-ZVI systems, while the second-order kinetics exhibited better fitting results in the 50 nm-ZVI system. And the different ZVI types exhibited difference on the AO7 degradation rate constant, which ranged as 50 nm-ZVI > 150 μm-ZVI > 1 mm-ZVI. The iron corrosion products coating on the ZVI after reaction were composed of α-Fe2 O3 and some Fe3O4 in the 1 mm-ZVI system while that consisted of Fe3O4 and α-Fe2O3, FeOOH respectively, in thel50 μm-ZVI and 50 nm-ZVI systems,. Which were identified by scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) and Raman spectroscopy. Some intermediate products, including 2-naphthalenol, 2-methylphenol, 4-ethyl- 3-methyl-phenol, isoindole- 1,3-dione and phthalic acid et al. were identified by GC/MS measurement. Both UV-vis absorbance spectra and GC/MS determination indicated that there was difference in degradation paths of AO7 between the three systems.

  7. Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

    Science.gov (United States)

    Anjum, Safia; Tufail, Rabia; Rashid, Khalid; Zia, Rehana; Riaz, S.

    2017-06-01

    This paper is dedicated to investigate the effect of Co2+ ions in magnetite Fe3O4 nano-particles with stoichiometric formula CoxFe3-xO4 where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co2+ doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV-Vis Spectrometer (UV-Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of CoxFe3-xO4 nanoparticles with the major band at 887 cm-1, which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co2+ content. The decrease in enthalpy with increase in Co2+ concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co2+ content in B-site of Fe3O4 structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of CoxFe3-xO4 nanoparticles are significantly increased. From UV-Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

  8. Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Anjum, Safia, E-mail: safia_anjum@hotmail.com [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Tufail, Rabia [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Rashid, Khalid [PCSIR Laboratories Lahore (Pakistan); Zia, Rehana [Department of Physics, Lahore College for Women University, Lahore (Pakistan); Riaz, S. [Centre for Solid State Physics, University of the Punjab, Lahore (Pakistan)

    2017-06-15

    Highlights: • The stability of Co{sub x}Fe{sub (2-x)}O{sub 3} nanoparticles enhances. • Energy losses increases. • Anisotropy of NP is high. - Abstract: This paper is dedicated to investigate the effect of Co{sup 2+} ions in magnetite Fe{sub 3}O{sub 4} nano-particles with stoichiometric formula Co{sub x}Fe{sub 3-x}O{sub 4} where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co{sup 2+} doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV–Vis Spectrometer (UV–Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of Co{sub x}Fe{sub 3-x}O{sub 4} nanoparticles with the major band at 887 cm{sup −1}, which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co{sup 2+} content. The decrease in enthalpy with increase in Co{sup 2+} concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co{sup 2+} content in B-site of Fe{sub 3}O{sub 4} structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of Co{sub x}Fe{sub 3-x}O{sub 4} nanoparticles are significantly increased. From UV–Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

  9. Molecular Detection of Malaria at Delivery Reveals a High Frequency of Submicroscopic Infections and Associated Placental Damage in Pregnant Women from Northwest Colombia

    Science.gov (United States)

    Arango, Eliana M.; Samuel, Roshini; Agudelo, Olga M.; Carmona-Fonseca, Jaime; Maestre, Amanda; Yanow, Stephanie K.

    2013-01-01

    Plasmodium infection in pregnancy causes substantial maternal and infant morbidity and mortality. In Colombia, both P. falciparum and P. vivax are endemic, but the impact of either species on pregnancy is largely unknown in this country. A cross-sectional study was carried out with 96 pregnant women who delivered at their local hospital. Maternal, placental, and cord blood were tested for malaria infection by microscopy and real-time quantitative polymerase chain reaction (qPCR). A high frequency of infection was detected by qPCR (45%). These infections had low concentrations of parasite DNA, and 79% were submicroscopic. Submicroscopic infections were associated with placental villitis and intervillitis. In conclusion, the overall frequency of Plasmodium infection at delivery in Colombia is much higher than previously reported. These data prompt a re-examination of the local epidemiology of malaria using molecular diagnostics to establish the clinical relevance of submicroscopic infections during pregnancy as well as their consequences for mothers and newborns. PMID:23716408

  10. SBA-15-incorporated nanoscale zero-valent iron particles for chromium(VI) removal from groundwater: Mechanism, effect of pH, humic acid and sustained reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xia, E-mail: lygsunxia@163.com [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Chemistry and Chemical Engineering, Huaihai Institute of Technology, Lianyungang 222005 (China); Yan, Yubo [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Li, Jiansheng, E-mail: lijsh@mail.njust.edu.cn [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Han, Weiqing [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Wang, Lianjun, E-mail: wanglj@mail.njust.edu.cn [School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2014-02-15

    Highlights: • Zero-valent iron nanoparticles were incorporated in the pores of SBA-15 rods. • Mechanism of the Cr(VI) removal by NZVIs/SBA-15 was proposed. • A low pH value was in favor of the Cr(VI) removal. • Humic acid (HA) had a negligible effect on the reactivity of NZVIs/SBA-15. • The stable reduction of NZVIs/SBA-15 was observed within six cycles. -- Abstract: Nanoscale zero-valent iron particles (NZVIs) were incorporated inside the channels of SBA-15 rods by a “two solvents” reduction technique and used to remove Cr(VI) from groundwater. The resulting NZVIs/SBA-15 composites before and after reaction were characterized by N{sub 2} adsorption/desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Results helped to propose the mechanism of Cr(VI) removal by NZVIs/SBA-15, where Cr(VI) in aqueous was firstly impregnated into the channels of the silica, then adsorbed on the surfaces of the incorporated NZVIs and reduced to Cr(III) directly in the inner pores of the silica. Corrosion products included Fe{sub 2}O{sub 3}, FeO(OH), Fe{sub 3}O{sub 4} and Cr{sub 2}FeO{sub 4}. Batch experiments revealed that Cr(VI) removal decreased from 99.7% to 92.8% when the initial solution pH increased from 5.5 to 9.0, accompanied by the decrease of the k{sub obs} from 0.600 to 0.024 min{sup −1}. Humic acid (HA) had a little effect on the removal efficiency of Cr(VI) by NZVIs/SBA-15 but could decrease the reduction rate. The stable reduction of NZVIs/SBA-15 was observed within six cycles. NZVIs/SBA-15 composites offer a promising alternative material to remove heavy metals from groundwater.

  11. SBA-15-incorporated nanoscale zero-valent iron particles for chromium(VI) removal from groundwater: mechanism, effect of pH, humic acid and sustained reactivity.

    Science.gov (United States)

    Sun, Xia; Yan, Yubo; Li, Jiansheng; Han, Weiqing; Wang, Lianjun

    2014-02-15

    Nanoscale zero-valent iron particles (NZVIs) were incorporated inside the channels of SBA-15 rods by a "two solvents" reduction technique and used to remove Cr(VI) from groundwater. The resulting NZVIs/SBA-15 composites before and after reaction were characterized by N2 adsorption/desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Results helped to propose the mechanism of Cr(VI) removal by NZVIs/SBA-15, where Cr(VI) in aqueous was firstly impregnated into the channels of the silica, then adsorbed on the surfaces of the incorporated NZVIs and reduced to Cr(III) directly in the inner pores of the silica. Corrosion products included Fe2O3, FeO(OH), Fe3O4 and Cr2FeO4. Batch experiments revealed that Cr(VI) removal decreased from 99.7% to 92.8% when the initial solution pH increased from 5.5 to 9.0, accompanied by the decrease of the kobs from 0.600 to 0.024 min(-1). Humic acid (HA) had a little effect on the removal efficiency of Cr(VI) by NZVIs/SBA-15 but could decrease the reduction rate. The stable reduction of NZVIs/SBA-15 was observed within six cycles. NZVIs/SBA-15 composites offer a promising alternative material to remove heavy metals from groundwater. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Submicroscopic analysis of the genetic distrophy of visual cells in C3H mice.

    Science.gov (United States)

    LASANSKY, A; DE ROBERTIS, E

    1960-07-01

    The morphogenesis of the visual cells in the retina of DBA normal mice and in C3H mice having a genetic distrophy has been studied with the electron microscope. The stages of development previously described (3) have been confirmed. Two basal centrioles have been observed and an asymmetrical process of invagination of the surface membrane is recognized as the main source of the rod sacs in the outer segment. In the C3H mice the differentiation of the photoreceptors starts and reaches a certain stage but very early some alterations in the morphogenesis are observed. In the outer segment there appears a disorganized growth of membranous material that may invade the inner segment with disappearance of the normal connecting cilium. In the inner segment there is an increase of vesicular material and in the number of dense particles. In later stages the entire inner segment is filled with dense particles and the mitochondria degenerate. The synaptic junction with the bipolar cell, which reaches a certain degree of development, also shows early signs of degeneration. The observations reported have confirmed and extended the concept that the hereditary visual alterations of C3H mice are not the result of a primary arrested development but of a secondary alteration of the differentiating photoreceptor. In C3H mice the entire process of morphogenesis is disordered and leads to final involution and death. These findings are correlated with recent biochemical findings and are discussed with relation to the genetic mechanisms that may control normal morphogenesis.

  13. Iron nanoparticles grown in a carbon arc discharge

    NARCIS (Netherlands)

    Zhang, G.L.; du Marchie van Voorthuysen, E.H.; Szymanski, K.; Boom, G; Verwerft, M.G M; Jonkman, H.T.; Niesen, L

    1996-01-01

    Iron particles, encapsulated by graphite layers, were produced by means of the Kratschmer are discharge method in an iron pentacarbonyl atmosphere. The Mossbauer effect is dominated by the vibration of the particles as a whole. Superparamagnetism is dominant for iron oxide particles. No endohedral

  14. Formation, reactivity, and aging of ferric oxide particles formed from Fe(II) and Fe(III) sources: Implications for iron bioavailability in the marine environment

    Science.gov (United States)

    Bligh, Mark W.; Waite, T. David

    2011-12-01

    Freshly formed amorphous ferric oxides (AFO) in the water column are potentially highly reactive, but with reactivity declining rapidly with age, and have the capacity to partake in reactions with dissolved species and to be a significant source of bioavailable iron. However, the controls on reactivity in aggregated oxides are not well understood. Additionally, the mechanism by which early rapid aging occurs is not clear. Aging is typically considered in terms of changes in crystallinity as the structure of an iron oxide becomes more stable and ordered with time thus leading to declining reactivity. However, there has been recognition of the role that aggregation can play in determining reactivity, although it has received limited attention. Here, we have formed AFO in seawater in the laboratory from either an Fe(II) or Fe(III) source to produce either AFO(II) or AFO(III). The changes in reactivity of these two oxides following formation was measured using both ligand-promoted dissolution (LPD) and reductive dissolution (RD). The structure of the two oxides was examined using light scattering and X-ray adsorption techniques. The dissolution rate of AFO(III) was greater than that of AFO(II), as measured by both dissolution techniques, and could be attributed to both the less ordered molecular structure and smaller primary particle size of AFO(III). From EXAFS analysis shortly (90 min) following formation, AFO(II) and AFO(III) were shown to have the same structure as aged lepidocrocite and ferrihydrite respectively. Both oxides displayed a rapid decrease in dissolution rate over the first hours following formation in a pattern that was very similar when normalised. The early establishment and little subsequent change of crystal structure for both oxides undermined the hypothesis that increasing crystallinity was responsible for early rapid aging. Also, an aging model describing this proposed process could only be fitted to the data with kinetic parameters that were

  15. Cardiac magnetic resonance angiography using blood-pool contrast agents: comparison of citrate-coated very small superparamagnetic iron oxide particles with gadofosveset trisodium in pigs.

    Science.gov (United States)

    Schnorr, J; Taupitz, M; Schellenberger, E A; Warmuth, C; Fahlenkamp, U L; Wagner, S; Kaufels, N; Wagner, M

    2012-02-01

    To compare citrate-coated very small superparamagnetic iron oxide particles (VSOP) with gadofosveset trisodium as blood pool contrast agents for cardiac magnetic resonance angiography (CMRA) in pigs. Animal experiments were approved by the responsible authority. 10 CMRA-like examinations were performed at 1.5 T after administration of VSOP (0.06  mmol Fe/kg; 5 examinations) and gadofosveset trisodium (0.03  mmol Gd/kg; 5 examinations). The CMRA protocol included ECG-gated inversion-recovery-prepared T1-weighted gradient echo imaging (IR-GRE; one slice) and ECG-gated inversion recovery prepared steady state free precession imaging (IR SSFP; one slice) before and 1, 3, 5, 10, 15, 20, 25, 30, 40, 50, and 60  min after injection. At each time point, three different inversion times (TI; 200  msec, 300  msec, and 400  msec) were applied. Contrast-to-noise ratios (CNR) between blood and myocardium were calculated and compared using mixed linear models. No significant differences of CNR were found between IR-GRE and IR SSFP. At 3 and 5  min after contrast agent administration, VSOP showed a significantly higher CNR than gadofosveset trisodium when TI of 200  msec and 300 msec were applied (TI of 200  msec at 3 min: 8.2 ± 0.7 vs. 5.4 ± 0.7; TI of 200  msec at 5 min: 7.9 ± 0.7 vs. 3.5 ± 0.8; TI of 300  msec at 3  min: 11.7 ± 0.7 vs. 8.8 ± 0.8; TI of 300  msec at 5  min: 11.4 ± 0.7 vs. 8.0 ± 0.8; p properties compared to gadofosveset trisodium resulting in prolonged improvement of CNR on CMRA. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Accelerated dissolution of iron oxides in ice

    Directory of Open Access Journals (Sweden)

    D. Jeong

    2012-11-01

    Full Text Available Iron dissolution from mineral dusts and soil particles is vital as a source of bioavailable iron in various environmental media. In this work, the dissolution of iron oxide particles trapped in ice was investigated as a new pathway of iron supply. The dissolution experiments were carried out in the absence and presence of various organic complexing ligands under dark condition. In acidic pH conditions (pH 2, 3, and 4, the dissolution of iron oxides was greatly enhanced in the ice phase compared to that in water. The dissolved iron was mainly in the ferric form, which indicates that the dissolution is not a reductive process. The extent of dissolved iron was greatly affected by the kind of organic complexing ligands and the surface area of iron oxides. The iron dissolution was most pronounced with high surface area iron oxides and in the presence of strong iron binding ligands. The enhanced dissolution of iron oxides in ice is mainly ascribed to the "freeze concentration effect", which concentrates iron oxide particles, organic ligands, and protons in the liquid like ice grain boundary region and accelerates the dissolution of iron oxides. The ice-enhanced dissolution effect gradually decreased when decreasing the freezing temperature from −10 to −196 °C, which implies that the presence and formation of the liquid-like ice grain boundary region play a critical role. The proposed phenomenon of enhanced dissolution of iron oxides in ice may provide a new pathway of bioavailable iron production. The frozen atmospheric ice with iron-containing dust particles in the upper atmosphere thaws upon descending and may provide bioavailable iron upon deposition onto the ocean surface.

  17. Surface Engineering of Core/Shell Iron/Iron Oxide Nanoparticles from Microemulsions for Hyperthermia

    OpenAIRE

    Zhang, Guandong; Liao, Yifeng; Baker, Ian

    2010-01-01

    This paper describes the synthesis and surface engineering of core/shell-type iron/iron oxide nanoparticles for magnetic hyperthermia cancer therapy. Iron/iron oxide nanoparticles were synthesized from microemulsions of NaBH4 and FeCl3, followed by surface modification in which a thin hydrophobic hexamethyldisilazane layer - used to protect the iron core - replaced the CTAB coating on the particles. Phosphatidylcholine was then assembled on the nanoparticle surface. The resulting nanocomposit...

  18. APPLICATION OF SPHEROIDIZING «CHIPS»-MASTER ALLOY ON COPPER BASE CONTAINING NANOSCALE PARTICLES OF YTTRIUM OXIDE FOR HIGH-STRENGTH CAST IRON

    Directory of Open Access Journals (Sweden)

    A. S. Kalinichenko

    2016-01-01

    Full Text Available The peculiarity of the technology of obtaining high-strength cast iron is application in out-furnace treatment various inoculants containing magnesium. In practice of foundry production spheroidizing master alloys based on ferrosilicon (Fe-Si-Mg type and «heavy» alloying alloys on copper and nickel base are widespread. The urgent issue is to improve their efficiency by increasing the degree of magnesium assimilation, reduction of specific consumption of additives, and minimizing dust and gas emissions during the process of spheroidizing treatment of liquid iron. One method of solving this problem is the use of inoculants in a compact form in which the process of dissolution proceeds more efficiently. For example, rapidly quenched granules or «chip»-inoculants are interesting to apply.The aim of present work was to study the peculiarities of production and application of «Chips»-inoculants on copper and magnesium base with additions of yttrium oxide. The principle of mechatronics was used, including the briquetting inoculants’ components after their mixing with the subsequent high-speed mechanical impact and obtaining plates with a thickness of 1–2 mm.Spheroidizing treatment of molten metal has been produced by ladle method using «Chips»-inoculants in the amount of 0.8%. Secondary graphitization inoculation was not performed. Studies have shown that when the spheroidizing treatment of ductile iron was performed with inoculants developed, the process of interaction of magnesium with the liquid melt runs steadily without significant pyroeffect and emissions of metal outside of the ladle.This generates a structure of spheroidal graphite of regular shape (SGf5. The presence in the inoculant of yttrium oxide has a positive impact on the spheroidal graphite counts and the tendency of high-strength cast iron to form «white» cast iron structure. Mechanical properties of the obtained alloy correspond to high-strength cast iron HSCI60.

  19. Scattering Effect of Iron Metallic Particles on the Extinction Coefficient of CaO-SiO2-B2O3-Na2O-Fe2O3-CaF2 Glasses

    Science.gov (United States)

    Yoon, Dae-Woo; Cho, Jung-Wook; Kim, Seon-Hyo

    2016-10-01

    The extinction coefficient of the CaO-SiO2-B2O3-Na2O-Fe2O3-CaF2 glasses has been studied using a FT-IR and a UV-visible spectrometer in the range of 0.5-5 μm to investigate thermal radiation through glassy flux film during continuous casting of steels. In present investigations, iron oxide has been reduced to metallic iron droplets by reaction with graphite crucible during melting, which brings considerable increase of the extinction coefficient due to the scattering. To analyze the scattering effect of these droplets on the extinction coefficient, the number density and size parameter of metallic particles have been measured using an automated scanning electron microscope. The number of metallic particles is intensively proportional to boron contents due to the transition of molar structure, BO4 to BO3, with increasing boron oxide. It is found that calculated scattering coefficients based on Mie scattering theory are in good agreement with measured ones. As the increased scattering coefficient of glassy film would not cause any serious side effects on casting operations, utilization of scattering effects is believed to be significantly essential for the future design of commercial mold fluxes.

  20. Formation of carbon nanotubes on iron/cobalt oxides supported on zeolite-Y : Effect of zeolite textural properties and particle morphology

    NARCIS (Netherlands)

    Triantafyllidis, K. S.; Karakoulia, S. A.; Gournis, D.; Delimitis, A.; Nalbandian, L.; Maccallini, E.; Rudolf, P.

    2008-01-01

    The effect of the textural properties and morphology of zeolite Y, used as support of iron (Fe) or cobalt (Co) oxides, on the quantity and quality of the multi-wall carbon nanotubes (MWNTs) synthesized by catalytic chemical vapour deposition (CCVD) of acetylene was studied. The parent zeolite Y was

  1. 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....

  2. Iron Test

    Science.gov (United States)

    ... adrenocorticotropic hormone) can decrease them. Stress and sleep deprivation can temporarily decrease serum iron levels. Is iron ... Home About This Site Contact Us Terms Of Use In The News Policies Editorial Review Board Partner | ...

  3. Sorption of PAHs to humic acid- and iron(III)carbon ate particles by using passive dosing vials for investigating the transport of organic contamination in stormwater runoff

    DEFF Research Database (Denmark)

    Nielsen, Katrine; Mikkelsen, Peter Steen; Baun, Anders

    2013-01-01

    During the last decades, the growing urbanisation a nd increasing anthropogenic activities in urban areas have turned urban stormwater runoff int o a surface water quality contamination problem. The concerns of urban stormwater runoff as a source of contamination in the receiving surface water......) has been foun d to facilitate transport of organic contaminants and metals in stormwater runoff system s, but little is known about the role of the colloidal fraction including nano-sized particl es (0.001-1 μm). Based on the large specific surface area of colloids and nanosized particles, t heir...... for their ability to sorb polycyclic aromatic hydrocarbons (PAH’s) in an aqueous solution. These particles were used as indicators for stormwater particles which a re diverse in size and composition. For controlling the sorption onto the particles, passiv e doing vials were used (Birch et. al., 2010). Using passive...

  4. Pooled PCR testing strategy and prevalence estimation of submicroscopic infections using Bayesian latent class models in pregnant women receiving intermittent preventive treatment at Machinga District Hospital, Malawi, 2010.

    Science.gov (United States)

    Zhou, Zhiyong; Mitchell, Rebecca Mans; Gutman, Julie; Wiegand, Ryan E; Mwandama, Dyson A; Mathanga, Don P; Skarbinski, Jacek; Shi, Ya Ping

    2014-12-18

    Low malaria parasite densities in pregnancy are a diagnostic challenge. PCR provides high sensitivity and specificity in detecting low density of parasites, but cost and technical requirements limit its application in resources-limited settings. Pooling samples for PCR detection was explored to estimate prevalence of submicroscopic malaria infection in pregnant women at delivery. Previous work uses gold-standard based methods to calculate sensitivity and specificity of tests, creating a challenge when newer methodologies are substantially more sensitive than the gold standard. Thus prevalence was estimated using Bayesian latent class models (LCMs) in this study. Nested PCR (nPCR) for the 18S rRNA gene subunit of Plasmodium falciparum was conducted to detect malaria infection in microscopy-negative Malawian women on IPTp. Two-step sample pooling used dried blood spot samples (DBSs) collected from placenta or periphery at delivery. Results from nPCR and histology as well as previously published data were used to construct LCMs to estimate assay sensitivity and specificity. Theoretical confidence intervals for prevalence of infection were calculated for two-step and one-step pooling strategies. Of 617 microscopy-negative Malawian women, 39 (6.3%) were identified as actively infected by histology while 52 (8.4%) were positive by nPCR. One hundred forty (22.7%) individuals had past infection assessed by histology. With histology as a reference, 72% of women in the active infection group, 7.1% in the past infection group and 3.2% in histology-negative group were nPCR positive. Using latent class models without a gold standard, histology had a median sensitivity of 49.7% and specificity of 97.6% for active infection while PCR had a median sensitivity of 96.0% and specificity of 99.1%. The true prevalence of active infection was estimated at 8.0% (CI: 5.8-10.5%) from PCR. PCR also had similar sensitivity for detecting either peripheral or placental malaria for

  5. Chemical degradation of drinking water disinfection byproducts by millimeter-sized particles of iron-silicon and magnesium-aluminum alloys.

    Science.gov (United States)

    Li, Tianyu; Chen, Yongmei; Wan, Pingyu; Fan, Maohong; Yang, X Jin

    2010-03-03

    The candidature of Fe-Si and Mg-Al alloys at millimeter-scale particle sizes for chemical degradation of disinfection byproducts (DBPs) in drinking water systems was substantiated by their enhanced corrosion resistance and catalytic effect on the degradation. The Mg-Al particles supplied electrons for reductive degradation, and the Fe-Si particles acted as a catalyst and provided the sites for the reaction. The alloy particles are obtained by mechanical milling and stable under ambient conditions. The proposed method for chemical degradation of DBPs possesses the advantages of relatively constant degradation performance, long-term durability, no secondary contamination, and ease of handling, storage and maintenance in comparison with nanoparticle systems.

  6. Submicroscopic interstitial deletion of chromosome 11q22.3 in a girl with mild mental retardation and facial dysmorphism: Case report

    Directory of Open Access Journals (Sweden)

    Zagorac Andreja

    2011-08-01

    Full Text Available Abstract Background Except for terminal deletions that lead to Jacobsen syndrome, interstitial deletions involving the long arm of chromosome 11 are not frequently reported. A clinically distinct phenotype is usually observed in these cases, and no clear genotype-phenotype correlation is proposed. Results Here we present a case study of a 5-year-old girl with de novo submicroscopic deletion of chromosome 11q22.3 with mild mental retardation and facial dysmorphism. A standard cytogenetic analysis did not reveal any structural aberrations. In contrary, array-CGH analysis indicated a small deletion of 11q22.3. Discussion To our knowledge, this is the smallest 11q22.3 deletion reported in literature, containing nine RefSeq genes. Although none of the deleted genes are obvious candidates for the features observed in our patient, genes CUL5 and SLN could play a key role in the features described.

  7. Labeling of Luciferase/eGFP-expressing bone marrow-derived stromal cells with fluorescent micron-sized iron oxide particles improves quantitative and qualitative multimodal imaging of cellular grafts in vivo.

    Science.gov (United States)

    De Vocht, Nathalie; Bergwerf, Irene; Vanhoutte, Greetje; Daans, Jasmijn; De Visscher, Geofrey; Chatterjee, Shyama; Pauwels, Patrick; Berneman, Zwi; Ponsaerts, Peter; Van der Linden, Annemie

    2011-12-01

    Development of multimodal imaging strategies is currently of utmost importance for the validation of preclinical stem cell therapy studies. We performed a combined labeling strategy for bone marrow-derived stromal cells (BMSC) based on genetic modification with the reporter genes Luciferase and eGFP (BMSC-Luc/eGFP) and physical labeling with blue fluorescent micron-sized iron oxide particles (MPIO) in order to unambiguously identify BMSC localization, survival, and differentiation following engraftment in the central nervous system of mice by in vivo bioluminescence (BLI) and magnetic resonance imaging and postmortem histological analysis. Using this combination, a significant increase of in vivo BLI signal was observed for MPIO-labeled BMSC-Luc/eGFP. Moreover, MPIO labeling of BMSC-Luc/eGFP allows for the improved identification of implanted cells within host tissue during histological observation. This study describes an optimized labeling strategy for multimodal stem cell imaging resulting in improved quantitative and qualitative detection of cellular grafts.

  8. Stress effect of martensitic transformation of small iron particles in copper matrix. Dobosochu no tetsu bisho ryushi no martensite hentai ni oyobosu gairyoku koka

    Energy Technology Data Exchange (ETDEWEB)

    Kato, M.; Fujii, T.; Hoshino, Y.; Mori, T. (Tokyo Institute of Technology, Tokyo (Japan))

    1992-08-20

    There are two different ways of understanding the stress effects on martensitic transformation. To find out which one is more reasonable, examinations were given on the Stress- induced [mu][yields][alpha] martensitic transformation of iron particulates in monocrystalline copper matrix. The result revealed that out of 24 kinds of Kurdjumov-Sachs variants, the preferentially formed variants are various depending on the direction ([001][sub f] and [419][sub f]) and the sense (tension and compression). In addition, the easiness of generating a martensitic transformation depends upon the sense of external stresses. For example, when compared at the same plasticity shear distortion, the compression induced more martensite than tension at a stress of [001][sub f], but no significant difference was observed between the tension and the compression at a stress of [419][sub f], Further, in an experiment using polycrystalline copper-iron alloy specimens, the tensile stress had a greater effect on martensitic transformation than the compressive stress. 24 refs., 4 figs., 4 tabs.

  9. Magnetic study of iron sorbitol

    Energy Technology Data Exchange (ETDEWEB)

    Lazaro, F.J. E-mail: osoro@posta.unizar.es; Larrea, A.; Abadia, A.R.; Romero, M.S

    2002-09-01

    A magnetic study of iron sorbitol, an iron-containing drug to treat the iron deficiency anemia is presented. Transmission electron microscopy reveals that the system contains nanometric particles with an average diameter of 3 nm whose composition is close to two-line ferrihydrite. The characterisation by magnetisation and AC susceptibility measurements indicates superparamagnetic behaviour with progressive magnetic blocking starting at 8 K. The quantitative analysis of the magnetic results indicates that the system consists of an assembly of very small magnetic moments, presumably originated by spin uncompensation of the antiferromagnetic nanoparticles, with Arrhenius type magnetic dynamics.

  10. Iron refractory iron deficiency anemia

    Science.gov (United States)

    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 adulthood. The disease is refractory to oral iron treatment but shows a slow response to intravenous iron injections and partial correction of the anemia. To date, 40 different Matriptase-2 mutations have been reported, affecting all the functional domains of the large ectodomain of the protein. In vitro experiments on transfected cells suggest that Matriptase-2 cleaves Hemojuvelin, a major regulator of hepcidin expression and that this function is altered in this genetic form of anemia. In contrast to the low/undetectable hepcidin levels observed in acquired iron deficiency, in patients with Matriptase-2 deficiency, serum hepcidin is inappropriately high for the low iron status and accounts for the absent/delayed response to oral iron treatment. A challenge for the clinicians and pediatricians is the recognition of the disorder among iron deficiency and other microcytic anemias commonly found in pediatric patients. The current treatment of iron refractory iron deficiency anemia is based on parenteral iron administration; in the future, manipulation of the hepcidin pathway with the aim of suppressing it might become an alternative therapeutic approach. PMID:23729726

  11. Iron state in iron nanoparticles with and without zirconium

    Science.gov (United States)

    Filippov, V. P.; Khasanov, A. M.; Lauer, Yu. A.

    2017-11-01

    Mössbauer and X-ray methods are used for investigations of structure, stability and characteristics of pure-iron grain and two iron-zirconium alloys such as Fe + 5 wt.% Zr and Fe + 10 wt.% Zr. The used powder was ground for 24 h in a SPEX Model 8000 mill shaker. Complex nanoparticles are found, which change their properties under milling. Mössbauer spectral parameters are obtained for investigated materials. Milling results in formation of nanosized particles with two states of iron atoms: one main part is pure α-Fe and another part of iron atoms displaced in grain boundaries or defective zones in which hyperfine magnetic splitting decrease to ˜ 30.0 T. In alloys with Zr three iron states are formed in each alloy, main part of iron is in the form of α-Fe and another two states depend on the concentration of Zr and represent iron in grain boundaries with Zr atoms in nearest neighbor. The changing of iron states is discussed.

  12. 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...

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... your body doesn't have enough iron to build healthy red blood cells. Without enough iron, your ... Supplements Iron You may need iron supplements to build up your iron levels as quickly as possible. ...

  14. Preparation of nanoscale iron (oxide, oxyhydroxides and zero-valent) particles derived from blueberries: Reactivity, characterization and removal mechanism of arsenate.

    Science.gov (United States)

    Manquián-Cerda, Karen; Cruces, Edgardo; Angélica Rubio, María; Reyes, Camila; Arancibia-Miranda, Nicolás

    2017-11-01

    The application of iron nanoparticles (FeNPs) to the removal of various pollutants has received wide attention over the last few decades. A synthesis alternative to obtain these nanoparticles without using harmful chemical reagents, such as NaBH 4 , is the use of extracts from different natural sources that allow a lesser degree of agglomeration, in a process known as green synthesis. In this study, FeNPs were synthesized by 'green' (hereafter, BB-Fe NPs) and 'chemical' (hereafter, nZVI) methods. Extracts of leaves and blueberry shoots (Vaccinium corymbosum) were used as reducing agents for FeCl 3 ·6H 2 O solution in the green synthesis method. FeNPs were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrophoretic migration, Brunauer-Emmett-Teller (BET) surface area analysis and X-ray diffraction (XRD) and evaluated for the removal of As(V) from aqueous systems. In both synthesis methods, XRD analysis confirmed the presence of the different kinds of iron nanoparticles. SEM analysis showed that the average size of BB-Fe NPs was 52.4nm and that a variety of nanoparticles of different forms and associated structures, such as lepidocrocite, magnetite, and nZVI, were present, while the dimensions of nZVI were 80.2nm. Comparatively significant differences regarding the electrophoretic mobility were found between both materials pre- and post-sorption of As(V). The velocity of As(V) removal by BB-Fe NPs was slower than that by nZVI, reaching equilibrium at 120min compared to 60min for nZVI. The removal kinetics of As(V) were adequately described by the pseudo-second-order kinetic model, and the maximum adsorbed amounts of this analyte are in close accordance with the experimental results. The Langmuir-Freundlich model is in good agreement with our experimental data, where the sorption capacity of nZVI and BB-Fe NPs was found to be 52.23 ± 6.06 and 50.40 ± 5.90 (mg·g -1 ), respectively. The use of leaves of Vaccinium

  15. Verification and Validation of Monte Carlo n-Particle Code 6 (MCNP6) with Neutron Protection Factor Measurements of an Iron Box

    Science.gov (United States)

    2014-03-27

    determination to succeed at AFIT. His blessings have enriched my life enormously, and I am sincerely grateful for all of His influence in my life. I next...outer edges of 61 cm and a wall thickness of 2.5 cm. A deuterium –tritium (D-T) neutron accelerator served as the source for all incident particles...systems, utilizes a deuterium - deuterium fusion reaction to produce 2.45 MeV neutrons nearly isotropically from the target chamber. This reaction can be

  16. Submicroscopic deletions of 11q24-25 in individuals without Jacobsen syndrome: re-examination of the critical region by high-resolution array-CGH.

    Science.gov (United States)

    Tyson, Christine; Qiao, Ying; Harvard, Chansonette; Liu, Xudong; Bernier, Francois P; McGillivray, Barbara; Farrell, Sandra A; Arbour, Laura; Chudley, Albert E; Clarke, Lorne; Gibson, William; Dyack, Sarah; McLeod, Ross; Costa, Teresa; Vanallen, Margot I; Yong, Siu-Li; Graham, Gail E; Macleod, Patrick; Patel, Millan S; Hurlburt, Jane; Holden, Jeanette Ja; Lewis, Suzanne Me; Rajcan-Separovic, Evica

    2008-11-11

    Jacobsen syndrome is a rare contiguous gene disorder that results from a terminal deletion of the long arm of chromosome 11. It is typically characterized by intellectual disability, a variety of physical anomalies and a distinctive facial appearance. The 11q deletion has traditionally been identified by routine chromosome analysis. Array-based comparative genomic hybridization (array-CGH) has offered new opportunities to identify and refine chromosomal abnormalities in regions known to be associated with clinical syndromes. Using the 1 Mb BAC array (Spectral Genomics), we screened 70 chromosomally normal children with idiopathic intellectual disability (ID) and congenital abnormalities, and identified five cases with submicroscopic abnormalities believed to contribute to their phenotypes. Here, we provide detailed molecular cytogenetic descriptions and clinical presentation of two unrelated subjects with de novo submicroscopic deletions within chromosome bands 11q24-25. In subject 1 the chromosome rearrangement consisted of a 6.18 Mb deletion (from 128.25-134.43 Mb) and an adjacent 5.04 Mb duplication (from 123.15-128.19 Mb), while in subject 2, a 4.74 Mb interstitial deletion was found (from 124.29-129.03 Mb). Higher resolution array analysis (385 K Nimblegen) was used to refine all breakpoints. Deletions of the 11q24-25 region are known to be associated with Jacobsen syndrome (JBS: OMIM 147791). However, neither of the subjects had the typical features of JBS (trigonocephaly, platelet disorder, heart abnormalities). Both subjects had ID, dysmorphic features and additional phenotypic abnormalities: subject 1 had a kidney abnormality, bilateral preauricular pits, pectus excavatum, mild to moderate conductive hearing loss and behavioral concerns; subject 2 had macrocephaly, an abnormal MRI with delayed myelination, fifth finger shortening and squaring of all fingertips, and sensorineural hearing loss. Two individuals with ID who did not have the typical clinical

  17. High Rates of Asymptomatic, Sub-microscopic Plasmodium vivax Infection and Disappearing Plasmodium falciparum Malaria in an Area of Low Transmission in Solomon Islands.

    Science.gov (United States)

    Waltmann, Andreea; Darcy, Andrew W; Harris, Ivor; Koepfli, Cristian; Lodo, John; Vahi, Ventis; Piziki, David; Shanks, G Dennis; Barry, Alyssa E; Whittaker, Maxine; Kazura, James W; Mueller, Ivo

    2015-05-01

    Solomon Islands is intensifying national efforts to achieve malaria elimination. A long history of indoor spraying with residual insecticides, combined recently with distribution of long lasting insecticidal nets and artemether-lumefantrine therapy, has been implemented in Solomon Islands. The impact of these interventions on local endemicity of Plasmodium spp. is unknown. In 2012, a cross-sectional survey of 3501 residents of all ages was conducted in Ngella, Central Islands Province, Solomon Islands. Prevalence of Plasmodium falciparum, P. vivax, P. ovale and P. malariae was assessed by quantitative PCR (qPCR) and light microscopy (LM). Presence of gametocytes was determined by reverse transcription quantitative PCR (RT-qPCR). By qPCR, 468 Plasmodium spp. infections were detected (prevalence = 13.4%; 463 P. vivax, five mixed P. falciparum/P. vivax, no P. ovale or P. malariae) versus 130 by LM (prevalence = 3.7%; 126 P. vivax, three P. falciparum and one P. falciparum/P. vivax). The prevalence of P. vivax infection varied significantly among villages (range 3.0-38.5%, p<0.001) and across age groups (5.3-25.9%, p<0.001). Of 468 P. vivax infections, 72.9% were sub-microscopic, 84.5% afebrile and 60.0% were both sub-microscopic and afebrile. Local residency, low education level of the household head and living in a household with at least one other P. vivax infected individual increased the risk of P. vivax infection. Overall, 23.5% of P. vivax infections had concurrent gametocytaemia. Of all P. vivax positive samples, 29.2% were polyclonal by MS16 and msp1F3 genotyping. All five P. falciparum infections were detected in residents of the same village, carried the same msp2 allele and four were positive for P. falciparum gametocytes. P. vivax infection remains endemic in Ngella, with the majority of cases afebrile and below the detection limit of LM. P. falciparum has nearly disappeared, but the risk of re-introductions and outbreaks due to travel to nearby islands

  18. Iron Test

    Science.gov (United States)

    ... Pregnancy hCG Tumor Marker HDL Cholesterol Heavy Metals Helicobacter pylori Testing Hematocrit Hemoglobin Hemoglobin A1c Hemoglobinopathy Evaluation ... not enough iron is taken in from the diet, blood levels will drop; thus, over time, the ...

  19. Sedimentary particulate iron: the missing micronutrients ?

    Science.gov (United States)

    Beghoura, Houda; Gorgues, Thomas; Aumont, Olivier; Planquette, Hélène

    2017-04-01

    Iron is known to regulate the marine primary production and to impact the structure of ecosystems. Indeed, iron is the limiting nutrient for the phytoplankton growth over about 30% of the global ocean. However, the nature of the external sources of iron to the ocean and their quantification remain uncertain. Among these external sources, the sediment sources have been recently shown to be underestimated. Besides, since the operationally defined dissolved iron (which is the sum of truly dissolved and colloidal iron) was traditionally assumed to be the only form available to phytoplankton and bacteria, most studies have focused on the supply of dissolved iron to the ocean, the role of the particulate fraction of iron being largely ignored. This traditional view has been recently challenged, noticeably, by observational evidences. Indeed, in situ observations have shown that large amounts of particulate iron are being resuspended from continental margins to the open ocean thanks to fine grained particles' transport over long distances. A fraction of this particulate iron may dissolve and thereby fuel the phytoplankton growth. The magnitude of the sedimentary sources of particulate iron and the releasing processes affecting this iron phase are not yet well constrained or quantified. As a consequence, the role of sedimentary particulate iron in the biogeochemical cycles is still unclear despite its potentially major widespread importance. Here, we propose a modeling exercise to assess the first order impacts of this newly considered particulate sedimentary iron on global ocean biogeochemistry. We designed global experiments with a coupled dynamical-biogeochemical model (NEMO-PISCES). First, a control simulation that includes only a sediment source of iron in the dissolved phase has been run. Then, this control simulation is being compared with simulations, in which we include a sediment source of iron in both phases (dissolved as well as particulate). Those latter

  20. A 5-year-old white girl with Prader-Willi syndrome and a submicroscopic deletion of chromosome 15q11q13

    Energy Technology Data Exchange (ETDEWEB)

    Butler, M.G. [Vanderbilt Univ. Medical Center, Nashville, TN (United States); Christian, S.L.; Kubota, T.; Ledbetter, D.H. [National Inst. of Health, Bethesda, MD (United States)

    1996-10-16

    We report on a 5-year-old white girl with Prader-Willi syndrome (PWS) and a submicroscopic deletion of 15q11q13 of approximately 100-200 kb in size. High resolution chromosome analysis was normal but fluorescence in situ hybridization (FISH), Southern hybridization, and microsatellite data from the 15q11q13 region demonstrated that the deletion was paternal in origin and included the SNRPN, PAR-5, and PAR-7 genes from the proximal to distal boundaries of the deletion segment. SNRPN and PW71B methylation studies showed an abnormal pattern consistent with the diagnosis of PWS and supported the presence of a paternal deletion of 15q11q13 or an imprinting mutation. Biparental (normal) inheritance of PW71B (D15S63 locus) and a deletion of the SNRPN gene were observed by microsatellite, quantitative Southern hybridization, and/or FISH analyses. Our patient met the diagnostic criteria for PWS, but has no reported behavior problems, hyperphagia, or hypopigmentation. Our patient further supports SNRPN and possibly other genomic sequences which are deleted as the cause of the phenotype recognized in PWS patients. 21 refs., 7 figs.

  1. Magnetism and martensitic transformation of iron particles in a copper matrix; Cu boso chu no sekishutsu Fe ryushi no jikiteki henka to marutensaito hentai

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Y. [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering

    1995-07-20

    It is shown that the transformation process of Fe particles in Cu-Fe alloy can be traced by saturation magnetization measurement and magnetic anisotropy measurement. The effect of the magnetic transition of {gamma}-Fe on martensitic transformation and the magnetic field effect of antimagnetic {gamma}-Fe on martensitic transformation are also introduced. As a result of experiment, it is demonstrated that no {alpha}-Fe is formed during the aging up to 2.9Ms. The torque curves obtained by the experiment are analyzed theoretically from the viewpoints of crystalline magnetic anisotropy and shape magnetic anisotropy. The temperature dependency of the amount of martensitic transformation can be expected to change at the Neel temperature. The temperature dependency of yield strength agrees well with the temperature dependency of the amount of martensitic transformation. Simultaneous application of magnetic field and stress results in the induction of the state which causes transformation even below Neel temperature by stress, and it seems that additional magnetic field induced martensitic transformation occurs by the effect of the applied magnetic field. 45 refs., 6 figs.

  2. Chronic exposure of tilapia (Oreochromis niloticus) to iron oxide nanoparticles: Effects of particle morphology on accumulation, elimination, hematology and immune responses

    Science.gov (United States)

    Ates, Mehmet; Demir, Veysel; Arslan, Zikri; Kaya, Hasan; Yılmaz, Sevdan; Camas, Mustafa

    2016-01-01

    Effects of chronic exposure to alpha and gamma iron oxide nanoparticles (α-Fe2O3 and γ-Fe2O3 NPs) were investigated through exposure of tilapia (Oreochromis niloticus) to 0.1, 0.5 and 1.0 mg/L (9.2×10−4, 4.6×10−3 and 9.2×10−3 mM) aqueous suspensions for 60 days. Fish were then transferred to NP-free freshwater and allowed to eliminate ingested NPs for 30 days. The organs, including gills, liver, kidney, intestine, brain, spleen, and muscle tissue of the fish were analyzed to determine the accumulation, physiological distribution and elimination of the Fe2O3 NPs. Largest accumulation occurred in spleen followed by intestine, kidney, liver, gills, brain and muscle tissue. Fish exposed to γ-Fe2O3 NPs possessed significantly higher Fe in all organs. Accumulation in spleen was fast and independent of NP concentration reaching to maximum levels by the end of the first sampling period (30th day). Dissolved Fe levels in water were very negligible ranging at 4–6 μg/L for α-Fe2O3 and 17–21 μg/L for γ-Fe2O3 NPs (for 1 mg/L suspensions). Despite that, Fe levels in gills and brain reflect more dissolved Fe accumulation from metastable γ-Fe2O3 polymorph. Ingested NPs cleared from the organs completely within 30-day elimination period, except the liver and spleen. Liver contained about 31% of α- and 46% of γ-Fe2O3, while spleen retained about 62% of α- and 35% of the γ-polymorph. No significant disturbances were observed in hematological parameters, including hemoglobin, hematocrit, red blood cell and white blood cell counts (p > 0.05). Serum glucose (GLU) levels decreased in treatments exposed to 1.0 mg/L of γ-Fe2O3 NPs at day 30 (p 0.05), but increased significantly within elimination period due to mobilization of ingested NPs from liver and spleen to blood. Though respiratory burst activity was not affected (p > 0.05), lysozyme activity (LA) was suppressed suggesting an immunosuppressive effects from both Fe2O3 NPs (p < 0.05). In contrast

  3. Extending hydraulic lifetime of iron walls

    Energy Technology Data Exchange (ETDEWEB)

    Mackenzie, P.D. [General Electric Corp. Research and Development Center, Schenectady, NY (United States); Sivavec, T.M.; Horney, D.P.

    1997-12-31

    Iron walls for control of groundwaters contaminated with chlorinated solvents and reducible metals are becoming much more widely used and field studies of this technology have proven successful to date. However, there is still much uncertainty in predicting long-term performance. This work focuses on two factors affecting the lifetime of the iron media: plugging at the treatment zone entrance and precipitation in the bulk iron media. Plugging at the system entrance is due principally to dissolved oxygen in the incoming water and is an issue in aerobic aquifers or in ex-situ canister tests. In an in-situ treatment system, plugging would result in a dramatic reduction in flow through the iron zone. Designs to minimize plugging in field applications include use of larger iron particles and admixing sand of comparable size with the iron particles. Mineral precipitation in the bulk iron media can lead to porosity losses in the media, again reducing flow through the treatment zone. Decreases in reactivity of the iron media may also occur. The nature of the mineral precipitation and the factors that affect extent of mineral precipitation are examined by a variety of tools, including tracer tests, aqueous inorganic profiles, and surface analysis techniques. At short treatment times, measured porosity losses are due mainly to entrapment of a film of H{sub 2} gas on the iron surfaces and also to Fe(OH){sub 2} precipitation. Over longer treatment times precipitation of Fe(OH){sub 2} and FeCO{sub 3} in low carbonate waters and of Fe(OH){sub 2}, FeCO{sub 3} and CaCO{sub 3} in higher carbonate waters will begin to dominate porosity losses. Preliminary results of an on-going study to control pH in an iron zone by admixing iron sulfide with iron show no difference in extent of carbonate precipitation versus a 100% iron system, suggesting that these systems are supersaturated with respect to carbonate precipitation.

  4. Ferroxidase-Mediated Iron Oxide Biomineralization

    DEFF Research Database (Denmark)

    Zeth, Kornelius; Hoiczyk, Egbert; Okuda, Mitsuhiro

    2016-01-01

    Iron oxide biomineralization occurs in all living organisms and typically involves protein compartments ranging from 5 to 100nm in size. The smallest iron-oxo particles are formed inside dodecameric Dps protein cages, while the structurally related ferritin compartments consist of twice as many...... identical protein subunits. The largest known compartments are encapsulins, icosahedra made of up to 180 protein subunits that harbor additional ferritin-like proteins in their interior. The formation of iron-oxo particles in all these compartments requires a series of steps including recruitment of iron......, translocation, oxidation, nucleation, and storage, that are mediated by ferroxidase centers. Thus, compartmentalized iron oxide biomineralization yields uniform nanoparticles strictly determined by the sizes of the compartments, allowing customization for highly diverse nanotechnological applications....

  5. Magnetic properties of iron nanoparticles prepared by exploding wire technique

    OpenAIRE

    Alqudami, Abdullah; Annapoorni, S.; Lamba, Subhalakshmi; Kothari, P C; Kotnala, R K

    2006-01-01

    Nanoparticles of iron were prepared in distilled water using very thin iron wires and sheets, by the electro-exploding wire technique. Transmission electron microscopy reveals the size of the nanoparticles to be in the range 10 to 50 nm. However, particles of different sizes can be segregated by using ultrahigh centrifuge. X-ray diffraction studies confirm the presence of the cubic phase of iron. These iron nanoparticles were found to exhibit fluorescence in the visible region in contrast to ...

  6. Iron Dextran Injection

    Science.gov (United States)

    Iron dextran injection is used to treat iron-deficiency anemia (a lower than normal number of red blood ... be treated with iron supplements taken by mouth. Iron dextran injection is in a class of medications called ...

  7. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... re more likely to develop iron-deficiency anemia. Vegetarian diets can provide enough iron if you eat ... which are the best sources of iron. However, vegetarian diets can provide enough iron if you eat ...

  8. Iron-Deficiency Anemia

    Science.gov (United States)

    ... re more likely to develop iron-deficiency anemia. Vegetarian diets can provide enough iron if you eat ... which are the best sources of iron. However, vegetarian diets can provide enough iron if you eat ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron ... can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron ...

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark ... of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark ...

  11. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... enough iron, your body starts using the iron it has stored. Soon, the stored iron gets used ... fewer red blood cells. The red blood cells it does make have less hemoglobin than normal. Iron- ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... good nonmeat sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach ... good nonmeat sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach ...

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... The best sources of iron are meat, poultry, fish, and iron-fortified foods (foods that have iron ... you: Follow a diet that excludes meat and fish, which are the best sources of iron. However, ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other ... sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... drawings also can cause iron-deficiency anemia. Poor Diet The best sources of iron are meat, poultry, ... more likely to develop iron-deficiency anemia. Vegetarian diets can provide enough iron if you eat the ...

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron-deficiency anemia may require treatment in a hospital, blood transfusions , iron injections, or intravenous iron therapy. ... Treatment may need to be done in a hospital. The goals of treating iron-deficiency anemia are ...

  17. Ferrous iron content of intravenous iron formulations

    OpenAIRE

    Gupta, Ajay; Pratt, Raymond D; Crumbliss, Alvin L.

    2016-01-01

    The observed biological differences in safety and efficacy of intravenous (IV) iron formulations are attributable to physicochemical differences. In addition to differences in carbohydrate shell, polarographic signatures due to ferric iron [Fe(III)] and ferrous iron [Fe(II)] differ among IV iron formulations. Intravenous iron contains Fe(II) and releases labile iron in the circulation. Fe(II) generates toxic free radicals and reactive oxygen species and binds to bacterial siderophores and oth...

  18. Southern Ocean Iron Experiment (SOFex)

    Energy Technology Data Exchange (ETDEWEB)

    Coale, Kenneth H.

    2005-07-28

    The Southern Ocean Iron Experiment (SOFeX) was an experiment decades in the planning. It's implementation was among the most complex ship operations that SIO has been involved in. The SOFeX field expedition was successful in creating and tracking two experimentally enriched areas of the Southern Ocean, one characterized by low silicic acid, one characterized by high silicic acid. Both experimental sites were replete with abundant nitrate. About 100 scientists were involved overall. The major findings of this study were significant in several ways: (1) The productivity of the southern ocean is limited by iron availability. (2) Carbon uptake and flux is therefore controlled by iron availability (3) In spite of low silicic acid, iron promotes non-silicious phytoplankton growth and the uptake of carbon dioxide. (4) The transport of fixed carbon from the surface layers proceeds with a C:N ratio that would indicate differential remineralization of nitrogen at shallow depths. (5) These finding have major implications for modeling of carbon export based on nitrate utilization. (6) The general results of the experiment indicate that, beyond other southern ocean enrichment experiments, iron inputs have a much wider impact of productivity and carbon cycling than previously demonstrated. Scientific presentations: Coale, K., Johnson, K, Buesseler, K., 2002. The SOFeX Group. Eos. Trans. AGU 83(47) OS11A-0199. Coale, K., Johnson, K. Buesseler, K., 2002. SOFeX: Southern Ocean Iron Experiments. Overview and Experimental Design. Eos. Trans. AGU 83 (47) OS22D-01. Buesseler, K.,et al. 2002. Does Iron Fertilization Enhance Carbon Sequestration? Particle flux results from the Southern Ocean Iron Experiment. Eos. Trans. AGU 83 (47), OS22D-09. Johnson, K. et al. 2002. Open Ocean Iron Fertilization Experiments From IronEx-I through SOFeX: What We Know and What We Still Need to Understand. Eos. Trans. AGU 83 (47), OS22D-12. Coale, K. H., 2003. Carbon and Nutrient Cycling During the

  19. Iron deficiency

    DEFF Research Database (Denmark)

    Schou, Morten; Bosselmann, Helle; Gaborit, Freja

    2015-01-01

    BACKGROUND: Both iron deficiency (ID) and cardiovascular biomarkers are associated with a poor outcome in heart failure (HF). The relationship between different cardiovascular biomarkers and ID is unknown, and the true prevalence of ID in an outpatient HF clinic is probably overlooked. OBJECTIVES.......043). CONCLUSION: ID is frequent in an outpatient HF clinic. ID is not associated with cardiovascular biomarkers after adjustment for traditional confounders. Inflammation, but not neurohormonal activation is associated with ID in systolic HF. Further studies are needed to understand iron metabolism in elderly HF...

  20. The Impact of Chloride, Sulfate, and Bicarbonate on Iron Release from an Old Iron Pipe

    Science.gov (United States)

    “Colored water” describes the appearance of drinking water that contains suspended particulate iron where the actual suspension color may range from light yellow to red due to water chemistry and particle properties. This iron can originate from the source water and from distrib...

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... have enough iron stored in your body to make up for the lost iron, you'll develop iron- ... by mouth. This therapy also is given to people who need immediate treatment for iron-deficiency ... have iron-deficiency anemia, get ongoing care to make sure your iron levels are improving. At your ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... hospital, blood transfusions , iron injections, or intravenous iron therapy. Causes Not having enough iron in your body causes iron-deficiency anemia. Lack of iron usually is due to blood loss, poor diet, or an inability to absorb enough iron from ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron include iron-fortified breads and cereals, ... can provide enough iron if you eat the right foods. For example, good nonmeat sources of iron include iron-fortified breads and cereals, ...

  4. Submicroscopic deletions of 11q24-25 in individuals without Jacobsen syndrome: re-examination of the critical region by high-resolution array-CGH

    Directory of Open Access Journals (Sweden)

    VanAllen Margot I

    2008-11-01

    Full Text Available Abstract Background Jacobsen syndrome is a rare contiguous gene disorder that results from a terminal deletion of the long arm of chromosome 11. It is typically characterized by intellectual disability, a variety of physical anomalies and a distinctive facial appearance. The 11q deletion has traditionally been identified by routine chromosome analysis. Array-based comparative genomic hybridization (array-CGH has offered new opportunities to identify and refine chromosomal abnormalities in regions known to be associated with clinical syndromes. Results Using the 1 Mb BAC array (Spectral Genomics, we screened 70 chromosomally normal children with idiopathic intellectual disability (ID and congenital abnormalities, and identified five cases with submicroscopic abnormalities believed to contribute to their phenotypes. Here, we provide detailed molecular cytogenetic descriptions and clinical presentation of two unrelated subjects with de novo submicroscopic deletions within chromosome bands 11q24-25. In subject 1 the chromosome rearrangement consisted of a 6.18 Mb deletion (from 128.25–134.43 Mb and an adjacent 5.04 Mb duplication (from 123.15–128.19 Mb, while in subject 2, a 4.74 Mb interstitial deletion was found (from 124.29–129.03 Mb. Higher resolution array analysis (385 K Nimblegen was used to refine all breakpoints. Deletions of the 11q24-25 region are known to be associated with Jacobsen syndrome (JBS: OMIM 147791. However, neither of the subjects had the typical features of JBS (trigonocephaly, platelet disorder, heart abnormalities. Both subjects had ID, dysmorphic features and additional phenotypic abnormalities: subject 1 had a kidney abnormality, bilateral preauricular pits, pectus excavatum, mild to moderate conductive hearing loss and behavioral concerns; subject 2 had macrocephaly, an abnormal MRI with delayed myelination, fifth finger shortening and squaring of all fingertips, and sensorineural hearing loss. Conclusion Two

  5. Submicroscopic deletions of 11q24-25 in individuals without Jacobsen syndrome: re-examination of the critical region by high-resolution array-CGH

    Science.gov (United States)

    Tyson, Christine; Qiao, Ying; Harvard, Chansonette; Liu, Xudong; Bernier, Francois P; McGillivray, Barbara; Farrell, Sandra A; Arbour, Laura; Chudley, Albert E; Clarke, Lorne; Gibson, William; Dyack, Sarah; McLeod, Ross; Costa, Teresa; VanAllen, Margot I; Yong, Siu-li; Graham, Gail E; MacLeod, Patrick; Patel, Millan S; Hurlburt, Jane; Holden, Jeanette JA; Lewis, Suzanne ME; Rajcan-Separovic, Evica

    2008-01-01

    Background Jacobsen syndrome is a rare contiguous gene disorder that results from a terminal deletion of the long arm of chromosome 11. It is typically characterized by intellectual disability, a variety of physical anomalies and a distinctive facial appearance. The 11q deletion has traditionally been identified by routine chromosome analysis. Array-based comparative genomic hybridization (array-CGH) has offered new opportunities to identify and refine chromosomal abnormalities in regions known to be associated with clinical syndromes. Results Using the 1 Mb BAC array (Spectral Genomics), we screened 70 chromosomally normal children with idiopathic intellectual disability (ID) and congenital abnormalities, and identified five cases with submicroscopic abnormalities believed to contribute to their phenotypes. Here, we provide detailed molecular cytogenetic descriptions and clinical presentation of two unrelated subjects with de novo submicroscopic deletions within chromosome bands 11q24-25. In subject 1 the chromosome rearrangement consisted of a 6.18 Mb deletion (from 128.25–134.43 Mb) and an adjacent 5.04 Mb duplication (from 123.15–128.19 Mb), while in subject 2, a 4.74 Mb interstitial deletion was found (from 124.29–129.03 Mb). Higher resolution array analysis (385 K Nimblegen) was used to refine all breakpoints. Deletions of the 11q24-25 region are known to be associated with Jacobsen syndrome (JBS: OMIM 147791). However, neither of the subjects had the typical features of JBS (trigonocephaly, platelet disorder, heart abnormalities). Both subjects had ID, dysmorphic features and additional phenotypic abnormalities: subject 1 had a kidney abnormality, bilateral preauricular pits, pectus excavatum, mild to moderate conductive hearing loss and behavioral concerns; subject 2 had macrocephaly, an abnormal MRI with delayed myelination, fifth finger shortening and squaring of all fingertips, and sensorineural hearing loss. Conclusion Two individuals with ID who

  6. Submicroscopic chromosome imbalance in patients with developmental delay and/or dysmorphism referred specifically for Fragile X testing and karyotype analysis

    Directory of Open Access Journals (Sweden)

    Docherty Zoe

    2008-03-01

    Full Text Available Abstract Background Microdeletion syndromes are generally identified because they usually give rise to specific phenotypic features; many of these deletions are mediated by duplicons or LCRs. The phenotypes associated with subtelomeric deletions are also becoming recognised. However, reciprocal duplication events at these loci are less easily recognised and identified, as they may give rise to milder phenotypic features, and the individuals carrying them may not therefore be referred for appropriate testing. 403 patients with developmental delay and/or dysmorphism, referred to our Genetics Centre for karyotyping and Fragile X expansion testing, were assessed for chromosome imbalance by Multiplex Ligation-dependent Probe Amplification (MLPA. Two MLPA kits were used, one containing probes for the subtelomere regions, and one containing probes for common microdeletion loci. 321 patients were tested with both kits, 75 with the subtelomere kit alone, and 7 with the microdeletion kit alone. Results 32 patients had abnormal results; the overall abnormality detection rate was 2.5% for karyotype analysis and 7.2% for MLPA testing; 5.5% of subtelomere tests and 2.1% of microdeletion tests gave abnormal results. Of the abnormal MLPA results, 5 were in cases with cytogenetically visible abnormalities; of the remaining, submicroscopic, changes, 3 results were established as de novo and 8 were inherited; parental samples were not available for the remaining cases. None of the patients was found to have a Fragile X expansion. Conclusion Karyotype analysis in combination with MLPA assays for subtelomeres and microdeletion loci may be recommended for this patient group.

  7. Compound heterozygosity of a paternal submicroscopic deletion and a maternal missense mutation in POR gene: Antley-bixler syndrome phenotype in three sibling fetuses.

    Science.gov (United States)

    Tzetis, Maria; Konstantinidou, Anastasia; Sofocleous, Christalena; Kosma, Konstantina; Mitrakos, Anastasios; Tzannatos, Christina; Kitsiou-Tzeli, Sofia

    2016-07-01

    Antley-Bixler syndrome (ABS) is an exceptionally rare craniosynostosis syndrome that can be accompanied by disordered steroidogenesis, and is mainly caused by mutations in the POR gene, inherited in an autosomal recessive manner. Here we report the prenatal and postmortem findings of three sibling fetuses with ABS as a result of compound heterozygosity of a paternal submicroscopic deletion and a maternal missense mutation in the POR gene. Prenatal ultrasound and postmortem examination were performed in three sibling fetuses with termination of pregnancy at 22, 23, and 17 weeks of gestation, respectively. Molecular analysis of fetus 2 and 3 included (a) bidirectional sequencing of exon 8 of the POR gene after amplification of the specific locus by polymerase chain reaction, to detect single nucleotide variants (SNVs) and (b) high resolution comparative genomic hybridization (CGH) positive single nucleotide polymorphism array CGH (aCGH) analysis to detect copy number variants (CNVs), copy neutral areas of loss of heterozygosity and uniparental disomy. The diagnosis of ABS was suggested by the postmortem examination findings. The combination of the POR gene molecular analysis and aCGH revealed a compound heterozygous genotype of a maternal SNV (p.A287P) and a paternal CNV (NC_000007.13:g.(?_75608488)_(75615534_?)del). To the best of our knowledge, these sibling fetuses add to the few reported cases of ABS, caused by a combination of a SNV and a CNV in the POR gene. The detailed description of the pathologic and radiographic findings of second trimester fetuses affected with ABS adds novel knowledge concerning the early ABS phenotype, in lack of previous relevant reports. Birth Defects Research (Part A) 106:536-541, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  8. Chromosomal microarray analysis as a first-line test in pregnancies with a priori low risk for the detection of submicroscopic chromosomal abnormalities.

    Science.gov (United States)

    Fiorentino, Francesco; Napoletano, Stefania; Caiazzo, Fiorina; Sessa, Mariateresa; Bono, Sara; Spizzichino, Letizia; Gordon, Anthony; Nuccitelli, Andrea; Rizzo, Giuseppe; Baldi, Marina

    2013-07-01

    In this study, we aimed to explore the utility of chromosomal microarray analysis (CMA) in groups of pregnancies with a priori low risk for detection of submicroscopic chromosome abnormalities, usually not considered an indication for testing, in order to assess whether CMA improves the detection rate of prenatal chromosomal aberrations. A total of 3000 prenatal samples were processed in parallel using both whole-genome CMA and conventional karyotyping. The indications for prenatal testing included: advanced maternal age, maternal serum screening test abnormality, abnormal ultrasound findings, known abnormal fetal karyotype, parental anxiety, family history of a genetic condition and cell culture failure. The use of CMA resulted in an increased detection rate regardless of the indication for analysis. This was evident in high risk groups (abnormal ultrasound findings and abnormal fetal karyotype), in which the percentage of detection was 5.8% (7/120), and also in low risk groups, such as advanced maternal age (6/1118, 0.5%), and parental anxiety (11/1674, 0.7%). A total of 24 (0.8%) fetal conditions would have remained undiagnosed if only a standard karyotype had been performed. Importantly, 17 (0.6%) of such findings would have otherwise been overlooked if CMA was offered only to high risk pregnancies.The results of this study suggest that more widespread CMA testing of fetuses would result in a higher detection of clinically relevant chromosome abnormalities, even in low risk pregnancies. Our findings provide substantial evidence for the introduction of CMA as a first-line diagnostic test for all pregnant women undergoing invasive prenatal testing, regardless of risk factors.

  9. Discrimination of benign and malignant lymph nodes at 7.0T compared to 1.5T magnetic resonance imaging using ultrasmall particles of iron oxide: a feasibility preclinical study.

    Science.gov (United States)

    Kinner, Sonja; Maderwald, Stefan; Albert, Juliane; Parohl, Nina; Corot, Claire; Robert, Philippe; Baba, Hideo A; Barkhausen, Jörg

    2013-12-01

    To investigate the feasibility and performance of 7T magnetic resonance imaging compared to 1.5T imaging to discriminate benign (normal and inflammatory changed) from tumor-bearing lymph nodes in rabbits using ultrasmall particles of iron oxide (USPIO)-based contrast agents. Six New Zealand White rabbits were inoculated with either complete Freund's adjuvant cell suspension (n = 3) to induce reactively enlarged lymph nodes or with VX2 tumor cells to produce metastatic lymph nodes (n = 3). Image acquisition was performed before and 24 hours after bolus injection of an USPIO contrast agent at 1.5T and afterward at 7T using T1-weighted and T2*-weighted sequences. Sensitivities, specificities, and negative and positive predictive values for the detection of lymph node metastases were calculated for both field strengths with histopathology serving as reference standard. Sizes of lymph nodes with no, inflammatory, and malignant changes were compared using a Mann-Whitney U-test. All 24 lymph nodes were detected at 1.5T as well as at 7T. At 1.5T, sensitivity amounted to 0.67, while specificity reached a value of 1. At the higher field strength (7T), imaging was able to reach sensitivity and specificity values of 1. No statistical differences were detected concerning lymph node sizes. Magnetic resonance lymphography with USPIO contrast agents allows for differentiation of normal and reactively enlarged lymph nodes compared to metastatic nodes. First experiments at 7T show promising results compared to 1.5T, which have to be evaluated in further trials. Copyright © 2013. Published by Elsevier Inc.

  10. Iron and stony-iron meteorites

    DEFF Research Database (Denmark)

    Ruzicka, Alex M.; Haack, Henning; Chabot, Nancy L.

    2017-01-01

    By far most of the melted and differentiated planetesimals that have been sampled as meteorites are metal-rich iron meteorites or stony iron meteorites. The parent asteroids of these meteorites accreted early and differentiated shortly after the solar system formed, producing some of the oldest...... and interpretations for iron and stony iron meteorites (Plate 13.1). Such meteorites provide important constraints on the nature of metal-silicate separation and mixing in planetesimals undergoing partial to complete differentiation. They include iron meteorites that formed by the solidification of cores...... (fractionally crystallized irons), irons in which partly molten metal and silicates of diverse types were mixed together (silicate-bearing irons), stony irons in which partly molten metal and olivine from cores and mantles were mixed together (pallasites), and stony irons in which partly molten metal...

  11. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  12. [Iron dysregulation and anemias].

    Science.gov (United States)

    Ikuta, Katsuya

    2015-10-01

    Most iron in the body is utilized as a component of hemoglobin that delivers oxygen to the entire body. Under normal conditions, the iron balance is tightly regulated. However, iron dysregulation does occasionally occur; total iron content reductions cause iron deficiency anemia and overexpression of the iron regulatory peptide hepcidin disturbs iron utilization resulting in anemia of chronic disease. Conversely, the presence of anemia may ultimately lead to iron overload; for example, thalassemia, a common hereditary anemia worldwide, often requires transfusion, but long-term transfusions cause iron accumulation that leads to organ damage and other poor outcomes. On the other hand, there is a possibility that iron overload itself can cause anemia; iron chelation therapy for the post-transfusion iron overload observed in myelodysplastic syndrome or aplastic anemia improves dependency on transfusions in some cases. These observations reflect the extremely close relationship between anemias and iron metabolism.

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Research Home / < Back To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Leer en español What Is Iron-deficiency anemia ... cases, surgery may be advised. Treatments for Severe Iron-Deficiency Anemia Blood Transfusion If your iron-deficiency anemia is ...

  14. Visualisation of axolotl blastema cells and pig endothelial progenitor cells using very small super paramagnetic iron oxide particles in MRI: A technique with applications for non invasive visualisation of regenerative processes

    DEFF Research Database (Denmark)

    Lauridsen, Henrik; Kjær, N.B.; Bek, Maria

    Objectives: Regenerative studies on model animals often require invasive techniques such as tissue sampling and histology for visualisation of regenerative processes. These interactions are avoided using non invasive imaging techniques. The internalisation of very small super paramagnetic iron...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia What Is Iron-deficiency anemia is a common, ... all types of anemia . Signs and Symptoms of Anemia The most common symptom of all types of ...

  16. Iron and Your Child

    Science.gov (United States)

    ... extra iron in their diets. People following a vegetarian diet might also need added iron. What's Iron ... as Whole Milk? About Anemia Minerals What's a Vegetarian? Word! Anemia Anemia Food Labels Vitamins and Minerals ...

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... of red blood cells, hemoglobin, and iron. Dietary Changes and Supplements Iron You may need iron supplements ... are improving. At your checkups, your doctor may change your medicines or supplements. He or she also ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ... of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require ...

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Your doctor may advise you to eat more foods that are rich in iron. The best source ... iron from meat better than iron from nonmeat foods. However, some nonmeat foods also can help you ...

  20. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... the body. Iron-deficiency anemia usually develops over time if your body doesn't have enough iron ... because your need for iron increases during these times of growth and development. Inability To Absorb Enough ...

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... or iron supplements, when used properly, can help prevent iron-deficiency anemia in infants and young children. ... in the diet. Too much milk also may prevent children's bodies from absorbing iron from other foods. ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... have iron-deficiency anemia, you'll have a high level of transferrin that has no iron. Other ... may include dietary changes and supplements, medicines, and surgery. Severe iron-deficiency anemia may require a blood ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... also may help treat iron-deficiency anemia. Medical History Your doctor will ask about your signs and ... much of the transferrin in your blood isn't carrying iron. If you have iron-deficiency anemia, ...

  4. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ... or an inability to absorb enough iron from food. Blood Loss When you lose blood, you lose ...

  5. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron in your body (a condition called iron overload). Too much iron in your body can damage ... talk about their experiences with clinical research. More Information Related Health Topics Anemia Blood Tests Blood Transfusion ...

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... iron-deficiency anemia may require treatment in a hospital, blood transfusions , iron injections, or intravenous iron therapy. ... beans. Other lifestyle changes, such as getting enough sleep and exercising, also have helped Susan feel better. ...

  7. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... is low in iron. For this and other reasons, cow's milk isn't recommended for babies in ... iron in your body is low. For this reason, other iron tests also are done. Serum ferritin. ...

  8. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... been used. Transferrin level, or total iron-binding capacity. Transferrin is a protein that carries iron in your blood. Total iron-binding capacity measures how much of the transferrin in your ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Accessible Search Form Search the NHLBI, use the drop down list to select: the entire site, the ... enough iron. Your child's doctor may recommend iron drops. However, giving a child too much iron can ...

  10. Application of nuclear particle tracks: A scanning x-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, P.J.

    1991-09-30

    The scanning x-ray microscope (SXM) is a short-wavelength analog of a near-field optical-scanning microscope, promising spatial resolution of {approximately}100{angstrom} up to {approximately}5 keV x-ray energy. A portion of a synchrotron x-ray beam streams through an etched nuclear particle track in an opaque membrane and impinges on an object within the narrow stream. Scattered or transmitted x-rays are detected with a photon counter. The SXM is feasible because a useful number of synchrotron x-rays, even from a bend magnet, will stream through a small diameter pore. The properties and limitations of the SXM are discussed together with other submicroscopic applications of nuclear particle tracks. 14 refs., 8 figs., 1 tab.

  11. Genetics Home Reference: iron-refractory iron deficiency anemia

    Science.gov (United States)

    ... refractory iron deficiency anemia Iron-refractory iron deficiency anemia Printable PDF Open All Close All Enable Javascript ... expand/collapse boxes. Description Iron-refractory iron deficiency anemia is one of many types of anemia , which ...

  12. Anisotropic vector Preisach particle

    CERN Document Server

    Fuezi, J

    2000-01-01

    The static 2D vector magnetic behaviour of an anisotropic silicon iron sheet is modelled by a particle which depicts its space-averaged behaviour. The magnitude of magnetization is governed by a classical Preisach operator with the projection of field strength on the magnetization direction as input. Its orientation is determined by the equilibrium between the field strength orientation and the anisotropy of the sheet.

  13. Professional IronPython

    CERN Document Server

    Mueller, John Paul

    2010-01-01

    Part I: Introducing IronPython. This short part is designed to get the reader started using IronPython. It answers basic installation and usage questions, how to get help, and what makes IronPython different from other languages. The reader also discovers how to use familiar tools such as Visual Studio to work with IronPython and creates a very simple IronPython example. Most importantly, the reader becomes familiar with the IronPython environment and discovers how to use it.; Part II: Using the IronPython Language. In this part, the reader learns the IronPython language. It assumes that the r

  14. Iron and stony-iron meteorites

    DEFF Research Database (Denmark)

    Benedix, Gretchen K.; Haack, Henning; McCoy, T. J.

    2014-01-01

    Without iron and stony-iron meteorites, our chances of ever sampling the deep interior of a differentiated planetary object would be next to nil. Although we live on a planet with a very substantial core, we will never be able to sample it. Fortunately, asteroid collisions provide us with a rich...... sampling of the deep interiors of differentiated asteroids. Iron and stony-iron meteorites are fragments of a large number of asteroids that underwent significant geological processing in the early solar system. Parent bodies of iron and some stony-iron meteorites completed a geological evolution similar...... to that continuing on Earth – although on much smaller length- and timescales – with melting of the metal and silicates; differentiation into core, mantle, and crust; and probably extensive volcanism. Iron and stony-iron meteorites are our only available analogues to materials found in the deep interiors of Earth...

  15. Iron from Zealandic bog iron ore -

    DEFF Research Database (Denmark)

    Lyngstrøm, Henriette Syrach

    2011-01-01

    og geologiske materiale, metallurgiske analyser og eksperimentel arkæologiske forsøg - konturerne af en jernproduktion med udgangspunkt i den sjællandske myremalm. The frequent application by archaeologists of Werner Christensen’s distribution map for the occurrence of bog iron ore in Denmark (1966...... are sketched of iron production based on bog iron ore from Zealand....

  16. Production of iron from metallurgical waste

    Science.gov (United States)

    Hendrickson, David W; Iwasaki, Iwao

    2013-09-17

    A method of recovering metallic iron from iron-bearing metallurgical waste in steelmaking comprising steps of providing an iron-bearing metallurgical waste containing more than 55% by weight FeO and FeO equivalent and a particle size of at least 80% less than 10 mesh, mixing the iron-bearing metallurgical waste with a carbonaceous material to form a reducible mixture where the carbonaceous material is between 80 and 110% of the stoichiometric amount needed to reduce the iron-bearing waste to metallic iron, and as needed additions to provide a silica content between 0.8 and 8% by weight and a ratio of CaO/SiO.sub.2 between 1.4 and 1.8, forming agglomerates of the reducible mixture over a hearth material layer to protect the hearth, heating the agglomerates to a higher temperature above the melting point of iron to form nodules of metallic iron and slag material from the agglomerates by melting.

  17. Explosive formation of coherent particle jets

    Science.gov (United States)

    Frost, David; Ruel, Jean-Frederic; Zarei, Zouya; Goroshin, Sam; Gregoire, Yann; Zhang, Fan; Milne, Alec; Longbottom, Aaron

    2013-06-01

    A high-speed jet of solid particles may be formed by detonating an explosive layer lining the outside of a conically-shaped volume of particles. Experiments have been carried out to determine the velocity history and the coherency of a particle jet formed using this shaped-charge arrangement. Important parameters include the cone angle, the ratio of the masses of the explosive and particles, and the particle size and density. Dense particles (e.g., iron) form thin, stable, coherent jets, whereas lighter particles (e.g., glass or Al) lead to more diffuse jets. The jet velocities observed experimentally were close to the predictions from a Gurney velocity formulation for conical geometry. The effects of cone angle and particle density on the jet formation and development were explored with calculations using a multimaterial hydrocode. The simulations indicate that the converging shock and Mach disk within the particle bed have a strong influence on the uniformity of the particle density field. With iron particles, the particle volume remains coherent whereas for glass particles, during the particle acceleration phase, the shock interactions within the particle bed cause the particles to be concentrated in a thin shell surrounding a low density region.

  18. INCREASE OF EFFICIENCY OF MODIFIERS FOR GRAY CAST-IRON

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2012-01-01

    Full Text Available It is established that for the purpose of increase of modifying efficiency of the melt from gray cast iron it is possible to use mechanically alloyed aluminum powder with superdispersed particles of aluminum and graphite oxide.

  19. Composition of MBE-grown iron oxide films

    NARCIS (Netherlands)

    Voogt, F.C; Hibma, T; Smulders, P.J M; Niesen, L

    A wide range of iron oxides have been grown epitaxially on MgO(100) substrates using a dual beam technique in which the deposited iron is oxidised by a beam of NO2 particles. At high fluxes magnetite (Fe3-deltaO4) phases with compositions between near-stoichiometric magnetite (Fe3O4, delta = 0) and

  20. The Effects of Iron Filling On Some Mechanical and Physical ...

    African Journals Online (AJOL)

    This research work was aimed at producing particleboard from sawdust (matrix) and iron filling (particulate) under the same conditions as ordinary particleboard produced from sawdust alone and their properties compared. Sawdust –iron fillings particleboards were produced using a sawdust of particle size 1.18mm and ...

  1. Strain induced anomalous red shift in mesoscopic iron oxide ...

    Indian Academy of Sciences (India)

    Nonspherical mesoscopic iron oxide particles are also candidate materials for studying the shape, size and strain induced modifications of various physical properties viz. optical, magnetic and structural. Spherical and nonspherical iron oxides having an aspect ratio, ∼2, are synthesized by employing starch and ethylene ...

  2. Synthesis of iron oxide nanoparticles of narrow size distribution on ...

    Indian Academy of Sciences (India)

    WINTEC

    Diffuse reflectance UV–vis spectra values show that the template is completely removed from the final iron .... Starch is a complex carbohydrate which is insoluble in water; it is used by plants as a way to store excess glu- .... The X-ray diffraction pattern for iron oxide particles syn- thesized in the absence/presence of starch is ...

  3. Impact of coals and iron ores particles emissions from the western quay of Dunkirk on the atmospheric particular matter of Gravelines; Influence des emissions du quai a pondereux ouest du port autonome de Dunkerque sur la charge particulaire atmospherique presente a Gravelines

    Energy Technology Data Exchange (ETDEWEB)

    Deboudt, K.; Flament, P.; Bertho, M.L.; Dardier, St.; Puskaric, E. [Universite du Littoral, Laboratoire de Chimie Analytique appliquee a l`Environnement Naturel. Station Marine, 62 - Wimereux (France); Dupont, J.P. [Rouen Univ., 76 - Mont-Saint-Aignan (France)

    1997-04-01

    A million tons of coals and iron ores are continuously stocked on the west quay of Dunkirk`s independent Seaport. In order to estimate the impact of the emissions from the quay on the atmospheric particulate matter at Gravelines, a town which is 2 km far from the source, the emitted particles are followed by using carbon and iron as geochemical tracers. For that, atmospheric aerosols are sampled by cascade impaction at five points on the Gravelines - West Quay line. A physical characterization of ores and coals is also realized; the iron and carbon concentrations in aerosols and the `mass-size` functions evidence that the activities on the quay are responsible for an increase of the atmospheric particulate matter by a factor of five at the entrance of the town, even if the essential of dusts falls on the first thousands meters from the site. However, the granulometric profiles from the different sites show that this increase of the atmospheric load is not only due to the QPO. Finally, the measures obtained at the other end of the town able us to conclude that the rest of the emitted dust is scavenged on it. (authors)

  4. Serum iron test

    Science.gov (United States)

    Fe+2; Ferric ion; Fe++; Ferrous ion; Iron - serum; Anemia - serum iron; Hemochromatosis - serum iron ... A blood sample is needed. Iron levels are highest in the morning. Your health care provider will likely have you do this test in the morning.

  5. Iron deficiency anemia

    Science.gov (United States)

    Anemia - iron deficiency ... iron from old red blood cells. Iron deficiency anemia develops when your body's iron stores run low. ... You may have no symptoms if the anemia is mild. Most of the time, ... slowly. Symptoms may include: Feeling weak or tired more often ...

  6. Nutritional iron deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.; Hurrell, R.F.

    2007-01-01

    Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming

  7. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... as larger, full-term infants. Iron-fortified baby food or iron supplements, when used properly, can help prevent iron-deficiency ... Syndrome Other Resources Non-NHLBI Resources Anemia (MedlinePlus) "Dietary Supplement Fact Sheet: Iron" (Office of Dietary Supplements, National ...

  8. THE INFLUENCE OF OXIDANT TYPE ON THE PROPERTIES OF IRON COLLOIDS AND SUSPENSIONS FORMED FROM FERROUS IRON

    Science.gov (United States)

    "Red water" describes the appearance of drinking water that contains suspended particulate iron although the actual suspension color may be light yellow to brown depending on water chemistry and particle properties. Iron can originate from the source water and from distribution ...

  9. Surface effects in metallic iron nanoparticles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Linderoth, Søren

    1994-01-01

    Nanoparticles of metallic iron on carbon supports have been studied in situ by use of Mossbauer spectroscopy. The magnetic anisotropy energy constant increases with decreasing particle size, presumably because of the influence of surface anisotropy. Chemisorption of oxygen results in formation...

  10. Adsorption studies of iron (III) on chitin

    Indian Academy of Sciences (India)

    The effect of anions like chloride, nitrate and sulphate and also of cations like zinc, chromium and copper on the adsorption of iron(III) was determined. The time dependence of fraction of adsorption, , at varying particle sizes and doses of chitin and the intraparticle diffusion rate constants, , of the adsorption process ...

  11. The Particle Distribution in Liquid Metal with Ceramic Particles Mould Filling Process

    Science.gov (United States)

    Dong, Qi; Xing, Shu-ming

    2017-09-01

    Adding ceramic particles in the plate hammer is an effective method to increase the wear resistance of the hammer. The liquid phase method is based on the “with the flow of mixed liquid forging composite preparation of ZTA ceramic particle reinforced high chromium cast iron hammer. Preparation method for this system is using CFD simulation analysis the particles distribution of flow mixing and filling process. Taking the 30% volume fraction of ZTA ceramic composite of high chromium cast iron hammer as example, by changing the speed of liquid metal viscosity to control and make reasonable predictions of particles distribution before solidification.

  12. Polygamous particles

    OpenAIRE

    Wu, Kun-Ta; Feng, Lang; Sha, Ruojie; Dreyfus, Rémi; Grosberg, Alexander Y.; Seeman, Nadrian C.; Chaikin, Paul M.

    2012-01-01

    DNA is increasingly used as an important tool in programming the self-assembly of micrometer- and nanometer-scale particles. This is largely due to the highly specific thermoreversible interaction of cDNA strands, which, when placed on different particles, have been used to bind precise pairs in aggregates and crystals. However, DNA functionalized particles will only reach their true potential for particle assembly when each particle can address and bind to many different kinds of particles. ...

  13. Fundamentals and Applications of Magnetic Particle Imaging

    NARCIS (Netherlands)

    Borgert, J.; Schmidt, J.D.; Schmale, I.; Rahmer, J.; Bontus, C.; Gleich, B.; David, B.; Eckart, R.; Woywode, O.; Juergen Weizenecker; Schnorr, J.; Taupitz, M.; Haegele, J.; Vogt, F.; Barkhausen, J.

    2012-01-01

    Magnetic particle imaging (MPI) is a new medical imaging technique that performs a direct measurement of the magnetization of ferromagnetic nanoparticles to quantify their local concentration. These particles are usually called SPIOs, i.e. superparamagnetic iron oxides. Specific formulations of

  14. Magnethophoretic sorting of fluid catalytic cracking particles

    NARCIS (Netherlands)

    Solsona, Miguel; Nieuwelink, A. E.; Odijk, Mathieu; Meirer, Florian; Abelmann, Leon; Olthuis, Wouter; Weckhuysen, Bert M.; van den Berg, Albert; Lee, Abraham; DeVoe, Don

    2017-01-01

    We demonstrate an on-chip particle activity sorter, focused on iron concentration and based on magnetophoresis. This device was used for fast sorting of stepwise homogenously distributed [Fe]s. The preliminary results are very encouraging. We show that we can sort particles on magnetic moment, with

  15. Role of dust alkalinity in acid mobilization of iron

    Directory of Open Access Journals (Sweden)

    A. Ito

    2010-10-01

    Full Text Available Atmospheric processing of mineral aerosols by acid gases (e.g., SO2, HNO3, N2O5, and HCl may play a key role in the transformation of insoluble iron (Fe in the oxidized or ferric (III form to soluble forms (e.g., Fe(II, inorganic soluble species of Fe(III, and organic complexes of iron. On the other hand, mineral dust particles have a potential of neutralizing the acidic species due to the alkaline buffer ability of carbonate minerals (e.g., CaCO3 and MgCO3. Here we demonstrate the impact of dust alkalinity on the acid mobilization of iron in a three-dimensional aerosol chemistry transport model that includes a mineral dissolution scheme. In our model simulations, most of the alkaline dust minerals cannot be entirely consumed by inorganic acids during the transport across the North Pacific Ocean. As a result, the inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during the long-range transport to the North Pacific Ocean: only a small fraction of iron (<0.2% dissolves from hematite in the coarse-mode dust aerosols with 0.45% soluble iron initially. On the other hand, a significant fraction of iron (1–2% dissolves in the fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model quantitatively reproduces higher iron solubility in smaller particles as suggested by measurements over the Pacific Ocean. It implies that the buffering effect of alkaline content in dust aerosols might help to explain the inverse relationship between aerosol iron solubility and particle size. We also demonstrate that the iron solubility is sensitive to the chemical specification of iron-containing minerals in dust. Compared with the dust sources, soluble iron from combustion sources contributes to a relatively marginal effect for deposition of soluble iron over the North

  16. Mixed-valence cytoplasmic iron granules are linked to anaerobic respiration.

    Science.gov (United States)

    Glasauer, S; Langley, S; Boyanov, M; Lai, B; Kemner, K; Beveridge, T J

    2007-02-01

    Intracellular granules containing ferric and ferrous iron formed in Shewanella putrefaciens CN32 during dissimilatory reduction of solid-phase ferric iron. It is the first in situ detection at high resolution (150 nm) of a mixed-valence metal particle residing within a prokaryotic cell. The relationship of the internal particles to Fe(III) reduction may indicate a respiratory role.

  17. Thermally-activated deformation in dispersion-hardened polycrystalline iron at room temperature

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Cotteril, P.

    1970-01-01

    for the lattice friction stress in b.c.c. iron. It is concluded that the basic dislocation-lattice interaction in iron is modified by the presence of particles; the presence of particles is considered to alter (directly or indirectly) the dislocation segment lengths and their critical bulge-size giving rise...

  18. The study of processes of iron hydroxide coagulation and sedimentation

    Science.gov (United States)

    Fedorova, A. S.; Nedobukh, T. A.; Mashkovtsev, M. A.; Semenishchev, V. S.

    2017-09-01

    Migration behavior of radionuclides forming pseudoradiocolloids with iron hydroxide depends on physicochemical behavior of iron hydroxide. It was determined that pH of the solution and iron concentration are the main parameters affecting processes coagulation and sedimentation of iron hydroxide. Time dependences of iron hydroxide coagulation and sedimentation being obtained using ultrafiltration and turbidimetry methods were analyzed. Integral and differential curves of size distribution of iron hydroxide particles were obtained using the method of laser diffraction. At the whole pH range studied, monomodal size distribution was observed in the solution containing 25 mg L-1 of iron; whereas in the solution containing 100 mg L-1 of iron bimodal size distribution was observed. This difference indicates different mechanisms of coagulation that was additionally confirmed by analysis of kinetic curves. It was found that the best conditions for formation and further sedimentation of iron hydroxide were pH 6-8 and iron concentration of at least 50 mg L-1. At these conditions, the time of half-precipitation of the iron hydroxide precipitate did not exceed five minutes.

  19. Mining iron: Iron uptake and transport in plants

    National Research Council Canada - National Science Library

    Kim, Sun A; Guerinot, Mary Lou

    2007-01-01

    .... Iron transport within plants is also tightly controlled. New information has emerged on transporters that play a role in xylem loading and phloem loading/unloading of iron, and on the iron chelators involved in iron homeostasis...

  20. Iron deficiency in Europe.

    Science.gov (United States)

    Hercberg, S; Preziosi, P; Galan, P

    2001-04-01

    In Europe, iron deficiency is considered to be one of the main nutritional deficiency disorders affecting large fractions of the population, particularly such physiological groups as children, menstruating women and pregnant women. Some factors such as type of contraception in women, blood donation or minor pathological blood loss (haemorrhoids, gynaecological bleeding...) considerably increase the difficulty of covering iron needs. Moreover, women, especially adolescents consuming low-energy diets, vegetarians and vegans are at high risk of iron deficiency. Although there is no evidence that an absence of iron stores has any adverse consequences, it does indicate that iron nutrition is borderline, since any further reduction in body iron is associated with a decrease in the level of functional compounds such as haemoglobin. The prevalence of iron-deficient anaemia has slightly decreased in infants and menstruating women. Some positive factors may have contributed to reducing the prevalence of iron-deficiency anaemia in some groups of population: the use of iron-fortified formulas and iron-fortified cereals; the use of oral contraceptives and increased enrichment of iron in several countries; and the use of iron supplements during pregnancy in some European countries. It is possible to prevent and control iron deficiency by counseling individuals and families about sound iron nutrition during infancy and beyond, and about iron supplementation during pregnancy, by screening persons on the basis of their risk for iron deficiency, and by treating and following up persons with presumptive iron deficiency. This may help to reduce manifestations of iron deficiency and thus improve public health. Evidence linking iron status with risk of cardiovascular disease or cancer is unconvincing and does not justify changes in food fortification or medical practice, particularly because the benefits of assuring adequate iron intake during growth and development are well established

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

    Science.gov (United States)

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

    2018-02-01

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

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

    Science.gov (United States)

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

    2017-11-01

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

  3. The nanophase iron mineral(s) in Mars soil

    Science.gov (United States)

    Banin, A.; Ben-Shlomo, T.; Margulies, L.; Blake, D. F.; Mancinelli, R. L.; Gehring, A. U.

    1993-01-01

    A series of surface-modified clays containing nanophase (np) iron oxide/oxyhydroxides of extremely small particle sizes, with total iron contents as high as found in Mars soil, were prepared by iron deposition on the clay surface from ferrous chloride solution. Comprehensive studies of the iron mineralogy in these "Mars-soil analogs" were conducted using chemical extractions, solubility analyses, pH and redox, x ray and electron diffractometry, electron microscopic imaging, specific surface area and particle size determinations, differential thermal analyses, magnetic properties characterization, spectral reflectance, and Viking biology simulation experiments. The clay matrix and the procedure used for synthesis produced nanophase iron oxides containing a certain proportion of divalent iron, which slowly converts to more stable, fully oxidized iron minerals. The clay acted as an effective matrix, both chemically and sterically, preventing the major part of the synthesized iron oxides from ripening, i.e., growing and developing larger crystals. The precipitated iron oxides appear as isodiametric or slightly elongated particles in the size range 1-10 nm, having large specific surface area. The noncrystalline nature of the iron compounds precipitated on the surface of the clay was verified by their complete extractability in oxalate. Lepidocrocite (gamma-FeOOH) was detected by selected area electron diffraction. It is formed from a double iron Fe(II)/Fe(III) hydroxy mineral such as "green rust," or ferrosic hydroxide. Magnetic measurements suggested that lepidocrocite converted to the more stable maghemite (gamma-Fe2O3) by mild heat treatment and then to nanophase hematite (alpha-Fe2O3) by extensive heat treatment. After mild heating, the iron-enriched clay became slightly magnetic, to the extent that it adheres to a hand-held magnet, as was observed with Mars soil. The chemical reactivity of the iron-enriched clays strongly resembles, and offers a plausible mechanism

  4. Isolation of technogenic magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Catinon, Mickaël, E-mail: mickael.catinon@gmail.com [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Ayrault, Sophie, E-mail: sophie.ayrault@lsce.ispl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Boudouma, Omar, E-mail: boudouma@ccr.jussieu.fr [Service du MEB, UFR928, Université Pierre et Marie Curie, 75252 Paris VI (France); Bordier, Louise, E-mail: Louise.Bordier@lsce.ipsl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Agnello, Gregory, E-mail: contact@evinrude.fr [Evinrude, Espace St Germain, 38200 Vienne (France); Reynaud, Stéphane, E-mail: stephane.reynaud@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Tissut, Michel, E-mail: michel.tissut@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France)

    2014-03-01

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron + Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM–EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. - Highlights: • The developed method offers a low-cost approach of large-scale dry deposition. • Tombstones are excellent supports for sampling these atmospheric deposits. • Smelted elements crystallise after cooling, giving typical technogenic magnetic particles (TMPs). • Coupling microscopic and bulk analyses allows identifying TMP origin. • Magnetic TMPs issued from steel industry were separated by a new technique.

  5. Iron oxide surfaces

    Science.gov (United States)

    Parkinson, Gareth S.

    2016-03-01

    was recently challenged and a new structure based on a thin film of Fe3O4(111) on α-Fe2O3(0001) was proposed. The merits of the competing models are discussed. The α-Fe2O3(1 1 bar02) "R-cut" surface is recommended as an excellent prospect for future study given its apparent ease of preparation and its prevalence in nanomaterial. In the latter sections the literature regarding adsorption on iron oxides is reviewed. First, the adsorption of molecules (H2, H2O, CO, CO2, O2, HCOOH, CH3OH, CCl4, CH3I, C6H6, SO2, H2S, ethylbenzene, styrene, and Alq3) is discussed, and an attempt is made to relate this information to the reactions in which iron oxides are utilized as a catalyst (water-gas shift, Fischer-Tropsch, dehydrogenation of ethylbenzene to styrene) or catalyst supports (CO oxidation). The known interactions of iron oxide surfaces with metals are described, and it is shown that the behaviour is determined by whether the metal forms a stable ternary phase with the iron oxide. Those that do not, (e.g. Au, Pt, Ag, Pd) prefer to form three-dimensional particles, while the remainder (Ni, Co, Mn, Cr, V, Cu, Ti, Zr, Sn, Li, K, Na, Ca, Rb, Cs, Mg, Ca) incorporate within the oxide lattice. The incorporation temperature scales with the heat of formation of the most stable metal oxide. A particular effort is made to underline the mechanisms responsible for the extraordinary thermal stability of isolated metal adatoms on Fe3O4 surfaces, and the potential application of this model system to understand single atom catalysis and sub-nano cluster catalysis is discussed. The review ends with a brief summary, and a perspective is offered including exciting lines of future research.

  6. Inactivation of Pseudomonas aeruginosa by Chitosan Coated Iron Oxide Nanoparticles.

    Science.gov (United States)

    Mukherjee, Munmun; De, Sirshendu

    2016-01-01

    Pseudomonas aeruginosa is one of the potent opportunistic pathogens associated with respiratory and urinary tract infection. The bacterium owes its pathogenicity due to the intrinsic resistance to antibiotics and disinfectants. The present study is focused on the synthesis of antibacterial chitosan coated iron oxide nanoparticles for rapid inactivation of Pseudomonas aeruginosa. We have discussed the relevant patents on synthesis and antibacterial potential of metallic nanoparticles and chitosan. Chitosan coated iron oxide nanoparticles were synthesized by coprecipitation method at room temperature using non-toxic chitosan and iron salts in alkali media. The particles were characterized and evaluated for antibacterial property against Pseudomonas aeruginosa. The average size of the particles was measured as 52 nm. The surface area of the coated particles was as high as 90 ±5 m2/g. FTIR spectra confirmed the coating of chitosan on nanoparticles. The coated particles showed excellent antibacterial activity against the bacteria. The minimum inhibitory concentration of the coated particles was 105)µg mol-1. The morphological alteration and cytoplasmic leakage of bacteria were confirmed by SEM image and release of intracellular constituents, respectively. Higher 260 nm absorbance value confirmed stronger antibacterial activity of the coated nanoparticles as compared to pure chitosan and bare iron oxide nanoparticles. The study indicated that chitosan coated iron oxide nanoparticles have superior antibacterial property as compared to pure chitosan and iron oxide nanoparticles.

  7. Magnetic resonance imaging contrast of iron oxide nanoparticles developed for hyperthermia is dominated by iron content.

    Science.gov (United States)

    Wabler, Michele; Zhu, Wenlian; Hedayati, Mohammad; Attaluri, Anilchandra; Zhou, Haoming; Mihalic, Jana; Geyh, Alison; DeWeese, Theodore L; Ivkov, Robert; Artemov, Dmitri

    2014-05-01

    Magnetic iron oxide nanoparticles (MNPs) are used as contrast agents for magnetic resonance imaging (MRI) and hyperthermia for cancer treatment. The relationship between MRI signal intensity and cellular iron concentration for many new formulations, particularly MNPs having magnetic properties designed for heating in hyperthermia, is lacking. In this study, we examine the correlation between MRI T2 relaxation time and iron content in cancer cells loaded with various MNP formulations. Human prostate carcinoma DU-145 cells were loaded with starch-coated bionised nanoferrite (BNF), iron oxide (Nanomag® D-SPIO), Feridex™, and dextran-coated Johns Hopkins University (JHU) particles at a target concentration of 50 pg Fe/cell using poly-D-lysine transfection reagent. T2-weighted MRI of serial dilutions of these labelled cells was performed at 9.4 T and iron content quantification was performed using inductively coupled plasma mass spectrometry (ICP-MS). Clonogenic assay was used to characterise cytotoxicity. No cytotoxicity was observed at twice the target intracellular iron concentration (∼100 pg Fe/cell). ICP-MS revealed highest iron uptake efficiency with BNF and JHU particles, followed by Feridex and Nanomag-D-SPIO, respectively. Imaging data showed a linear correlation between increased intracellular iron concentration and decreased T2 times, with no apparent correlation among MNP magnetic properties. This study demonstrates that for the range of nanoparticle concentrations internalised by cancer cells the signal intensity of T2-weighted MRI correlates closely with absolute iron concentration associated with the cells. This correlation may benefit applications for cell-based cancer imaging and therapy including nanoparticle-mediated drug delivery and hyperthermia.

  8. LA-ICP-MS Allows Quantitative Microscopy of Europium-Doped Iron Oxide Nanoparticles and is a Possible Alternative to Ambiguous Prussian Blue Iron Staining.

    Science.gov (United States)

    Scharlach, Constantin; Müller, Larissa; Wagner, Susanne; Kobayashi, Yuske; Kratz, Harald; Ebert, Monika; Jakubowski, Norbert; Schellenberger, Eyk

    2016-05-01

    The development of iron oxide nanoparticles for biomedical applications requires accurate histological evaluation. Prussian blue iron staining is widely used but may be unspecific when tissues contain substantial endogenous iron. Here we tested whether microscopy by laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) is sensitive enough to analyze accumulation of very small iron oxide particles (VSOP) doped with europium in tissue sections. For synthesis of VSOP, a fraction of Fe3+ (5 wt%) was replaced by Eu3+, resulting in particles with 0.66 mol% europium relative to iron (Eu-VSOP) but with otherwise similar properties as VSOP. Eu-VSOP or VSOP was intravenously injected into ApoE-/- mice on Western cholesterol diet and accumulated in atherosclerotic plaques of these animals. Prussian blue staining was positive for ApoE-/- mice with particle injection but also for controls. LA-ICP-MS microscopy resulted in sensitive and specific detection of the europium of Eu-VSOP in liver and atherosclerotic plaques. Furthermore, calibration with Eu-VSOP allowed calculation of iron and particle concentrations in tissue sections. The combination of europium-doped iron oxide particles and LA-ICP-MS microscopy provides a new tool for specific and quantitative analysis of particle distribution at the tissue level and allows correlation with other elements such as endogenous iron.

  9. Iron-Deficiency Anemia

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    Full Text Available ... can lead to heart problems, infections, problems with growth and development in children, and other complications. Infants ... blood transfusions , iron injections, or intravenous iron therapy. Rate This Content: NEXT >> Featured Video Living With and ...

  10. Iron-Deficiency Anemia

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    Full Text Available ... less hemoglobin than normal. Iron-deficiency anemia can cause fatigue (tiredness), shortness of breath, chest pain, and ... iron-deficiency anemia. Treatment will depend on the cause and severity of the condition. Treatments may include ...

  11. Iron-Deficiency Anemia

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    Full Text Available ... also may help treat iron-deficiency anemia. Medical History Your doctor will ask about your signs and ... It must be done in a hospital or clinic by experienced staff. Iron therapy usually is given ...

  12. Iron-Deficiency Anemia

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    Full Text Available ... usually can successfully treat iron-deficiency anemia. Treatment will depend on the cause and severity of the ... about a healthy diet and food choices that will help your child get enough iron. Your child's ...

  13. Iron-Deficiency Anemia

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    Full Text Available ... you don't have enough iron in your body. Low iron levels usually are due to blood ... remove carbon dioxide (a waste product) from your body. Anemia also can occur if your red blood ...

  14. Iron-Deficiency Anemia

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    Full Text Available ... or soil, or drinking water that contains lead. Teens Teens are at risk for iron-deficiency anemia ... for increased blood volume and for the fetus' growth. About half of all pregnant women develop iron- ...

  15. Total iron binding capacity

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003489.htm Total iron binding capacity To use the sharing features on this page, please enable JavaScript. Total iron binding capacity (TIBC) is a blood test to ...

  16. Iron-Deficiency Anemia

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    Full Text Available ... food. Overview Iron-deficiency anemia is a common type of anemia . The term "anemia" usually refers to ... also may lead to iron-deficiency anemia. This type of blood loss isn't always obvious, and ...

  17. Iron-Deficiency Anemia

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    Full Text Available ... condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require treatment in ... Urinary tract bleeding Blood loss from severe injuries, surgery, or frequent blood drawings also can cause iron- ...

  18. Iron-Deficiency Anemia

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    Full Text Available ... and Blood Safety Sleep Science and Sleep Disorders Lung Diseases Heart and Vascular Diseases Precision Medicine Activities ... iron-rich protein that carries oxygen from the lungs to the rest of the body. Iron-deficiency ...

  19. Iron-Deficiency Anemia

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    Full Text Available ... infancy and childhood can have long-lasting, negative effects on brain health, the American Academy of Pediatrics ... overdose of iron. Iron supplements can cause side effects, such as dark stools, stomach irritation, and heartburn. ...

  20. Iron-Deficiency Anemia

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    Full Text Available ... condition. Women Women of childbearing age are at higher risk for iron-deficiency anemia because of blood ... iron-deficiency anemia. Pregnant women also are at higher risk for the condition because they need twice ...

  1. Iron-Deficiency Anemia

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    Full Text Available ... help prevent overdosing in children. Because recent research supports concerns that iron deficiency during infancy and childhood ... treat iron-deficiency anemia. These doctors include pediatricians, family doctors, gynecologists/obstetricians, and internal medicine specialists. A ...

  2. Iron-Deficiency Anemia

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    Full Text Available ... more information about diet and supplements, go to "How Is Iron-Deficiency Anemia Treated?" Infants and young ... who should be screened for iron deficiency, and how often: Girls aged 12 to 18 and women ...

  3. Iron supplements (image)

    Science.gov (United States)

    The mineral iron is an essential nutrient for humans because it is part of blood cells, which carry oxygen to all body cells. There is no conclusive evidence that iron supplements contribute to heart attacks.

  4. Iron-Deficiency Anemia

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    Full Text Available ... low iron levels in women. Internal bleeding (bleeding inside the body) also may lead to iron-deficiency ... a diagnosis, look for a cause, and find out how severe the condition is. Complete Blood Count ...

  5. Iron-Deficiency Anemia

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    Full Text Available ... inability to absorb enough iron from food. Blood Loss When you lose blood, you lose iron. If ... produce hemoglobin. Tests and Procedures for Gastrointestinal Blood Loss To check whether internal bleeding is causing your ...

  6. Iron-Deficiency Anemia

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    Full Text Available ... the cause and severity of the condition. Treatments may include dietary changes, medicines, and surgery. Severe iron-deficiency anemia may require treatment in a hospital, blood transfusions , iron ...

  7. Iron-Deficiency Anemia

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    Full Text Available ... and other symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and ... Internal bleeding (bleeding inside the body) also may lead to iron-deficiency anemia. This type of blood ...

  8. Iron-Deficiency Anemia

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    Full Text Available ... total amount of iron you need every day. Vitamin C Vitamin C helps the body absorb iron. Good sources of vitamin C are vegetables and fruits, especially citrus fruits. Citrus ...

  9. Iron-Deficiency Anemia

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    Full Text Available ... Deficiency Anemia Explore Iron-Deficiency Anemia What Is... CAUSES WHO IS AT RISK SIGNS & SYMPTOMS DIAGNOSIS TREATMENTS ... less hemoglobin than normal. Iron-deficiency anemia can cause fatigue (tiredness), shortness of breath, chest pain, and ...

  10. Iron-Deficiency Anemia

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    Full Text Available ... of fiber can slow the absorption of iron. Screening and Prevention Eating a well-balanced diet that ... pregnant women, medical care during pregnancy usually includes screening for anemia. Also, your doctor may prescribe iron ...

  11. Iron-Deficiency Anemia

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    Full Text Available ... iron-rich protein that carries oxygen from the lungs to the rest of the body. Iron-deficiency ... 2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National Institutes ...

  12. Iron in diet

    Science.gov (United States)

    ... iron; Ferric acid; Ferrous acid; Ferritin Images Iron supplements References Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, ...

  13. Iron-Deficiency Anemia

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    Full Text Available ... drawings also can cause iron-deficiency anemia. Poor Diet The best sources of iron are meat, poultry, ... also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal ...

  14. Iron-Deficiency Anemia

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    Full Text Available ... coped with having iron-deficiency anemia. Prior to her diagnosis, Susan had symptoms such as tiredness, poor skin tone, dizziness, and depression. After her doctor diagnosed her with iron-deficiency anemia, Susan ...

  15. Iron-Deficiency Anemia

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    Full Text Available ... specialists also may help treat iron-deficiency anemia. Medical History Your doctor will ask about your signs ... information, go to the Health Topics Blood Transfusion article. Iron Therapy If you have severe anemia, your ...

  16. Iron-Deficiency Anemia

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    Full Text Available ... an inability to absorb enough iron from food. Blood Loss When you lose blood, you lose iron. ... find out how severe the condition is. Complete Blood Count Often, the first test used to diagnose ...

  17. Iron-Deficiency Anemia

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    Full Text Available ... drawings also can cause iron-deficiency anemia. Poor Diet The best sources of iron are meat, poultry, ... other dark green leafy vegetables Prune juice The Nutrition Facts labels on packaged foods will show how ...

  18. Iron-Deficiency Anemia

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    Full Text Available ... Poor Diet The best sources of iron are meat, poultry, fish, and iron-fortified foods (foods that ... happen if you: Follow a diet that excludes meat and fish, which are the best sources of ...

  19. Iron-Deficiency Anemia

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    Full Text Available ... muh-glow-bin). Hemoglobin is an iron-rich protein that carries oxygen from the lungs to the ... hemoglobin than normal. Hemoglobin is an iron-rich protein in red blood cells. It helps red blood ...

  20. Iron-Deficiency Anemia

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    Full Text Available ... screened for iron deficiency, and how often: Girls aged 12 to 18 and women of childbearing age ... For this treatment, iron is injected into a muscle or an IV line in one of your ...

  1. Iron-Deficiency Anemia

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    Full Text Available ... stomach also can interfere with iron absorption. Risk Factors Infants and Young Children Infants and young children ... blood loss during their monthly periods Other risk factors for iron-deficiency anemia The Centers for Disease ...

  2. Iron-Deficiency Anemia

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    Full Text Available ... done in a hospital or clinic by experienced staff. Iron therapy usually is given to people who ... Resources Anemia (MedlinePlus) "Dietary Supplement Fact Sheet: Iron" (Office of Dietary Supplements, National Institutes of Health) Building ...

  3. Iron-Deficiency Anemia

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    Full Text Available ... some stages of life, such as pregnancy and childhood, it may be hard to get enough iron ... supports concerns that iron deficiency during infancy and childhood can have long-lasting, negative effects on brain ...

  4. Iron-Deficiency Anemia

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    Full Text Available ... For this treatment, iron is injected into a muscle or an IV line in one of your ... body can damage your organs. You may have fatigue (tiredness) and other symptoms of iron-deficiency anemia ...

  5. Iron-Deficiency Anemia

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    Full Text Available ... during these times of growth and development. Inability To Absorb Enough Iron Even if you have enough ... green vegetables like turnip greens and spinach. Treatment To Stop Bleeding If blood loss is causing iron- ...

  6. Iron-Deficiency Anemia

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    Full Text Available ... intravenous iron therapy. Rate This Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the National Heart, Lung, and Blood ...

  7. Iron-Deficiency Anemia

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    Full Text Available ... absorption of iron. Screening and Prevention Eating a well-balanced diet that includes iron-rich foods may ... the strength of a few medicines and how well they work. Other fruits rich in vitamin C ...

  8. Iron-Deficiency Anemia

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    Full Text Available ... prevent children's bodies from absorbing iron from other foods. Children who have lead in their blood also may be at risk for iron-deficiency anemia. Lead can interfere with ...

  9. Iron-Deficiency Anemia

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    Full Text Available ... easily treated condition that occurs if you don't have enough iron in your body. Low iron ... can occur if your red blood cells don't contain enough hemoglobin (HEE-muh-glow-bin). Hemoglobin ...

  10. Iron-Deficiency Anemia

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    Full Text Available ... Studies NHLBI Trials Clinical Trial Websites News & Resources Press Releases Spotlight On Research NHLBI In the News ... you don't have enough iron in your body. Low iron levels usually are due to blood ...

  11. Iron-Deficiency Anemia

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    Full Text Available ... Diseases Heart and Vascular Diseases Precision Medicine Activities Obesity, Nutrition, and Physical Activity Population and Epidemiology Studies ... or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ...

  12. Marine phytoplankton and the changing ocean iron cycle

    Science.gov (United States)

    Hutchins, D. A.; Boyd, P. W.

    2016-12-01

    The availability of the micronutrient iron governs phytoplankton growth across much of the ocean, but the global iron cycle is changing rapidly due to accelerating acidification, stratification, warming and deoxygenation. These mechanisms of global change will cumulatively affect the aqueous chemistry, sources and sinks, recycling, particle dynamics and bioavailability of iron. Biological iron demand will vary as acclimation to environmental change modifies cellular requirements for photosynthesis and nitrogen acquisition and as adaptive evolution or community shifts occur. Warming, acidification and nutrient co-limitation interactions with iron biogeochemistry will all strongly influence phytoplankton dynamics. Predicting the shape of the future iron cycle will require understanding the responses of each component of the unique biogeochemistry of this trace element to many concurrent and interacting environmental changes.

  13. Graphitized Cast Irons

    Science.gov (United States)

    Silman, G. I.; Makarenko, K. V.

    2014-05-01

    An analytical review of data on general-purpose grayed cast iron with different forms of graphite (lamellar, vermicular, globular, flaked) is presented. Grades of cast iron, their compositions, special features of structure of the graphite, and properties of gray, high-strength and malleable irons are described. The data on the kinds of iron considered are compared with those stipulated in international and some national standards.

  14. Iron-Deficiency Anemia

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    Full Text Available ... the best sources of iron. Follow a high-fiber diet. Large amounts of fiber can slow the absorption of iron. Screening and Prevention Eating a well-balanced diet that includes iron-rich foods may help you ...

  15. Iron-Deficiency Anemia

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    Full Text Available ... diet. Young children who drink a lot of cow's milk may be at risk for iron-deficiency anemia. ... her risk for iron-deficiency anemia. For example, cow's milk is low in iron. For this and other ...

  16. Iron-Deficiency Anemia

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    Full Text Available ... Organization NHLBI Director Budget, Planning, & Legislative Advisory Committees Jobs Contact Us FAQs Home » Iron-Deficiency Anemia Explore ... the body. Iron-deficiency anemia usually develops over time if your body doesn't have enough iron ...

  17. Iron and Immunity

    NARCIS (Netherlands)

    Verbon, E.H.; Trapet, P.L.; Stringlis, I.|info:eu-repo/dai/nl/41185206X; Kruijs, Sophie; Bakker, P.A.H.M.|info:eu-repo/dai/nl/074744623; Pieterse, C.M.J.|info:eu-repo/dai/nl/113115113

    2017-01-01

    Iron is an essential nutrient for most life on Earth because it functions as a crucial redox catalyst in many cellular processes. However, when present in excess iron can lead to the formation of harmful hydroxyl radicals. Hence, the cellular iron balance must be tightly controlled. Perturbation of

  18. Iron-Deficiency Anemia

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    Full Text Available ... To Health Topics / Iron-Deficiency Anemia Iron-Deficiency Anemia Leer en español What Is Iron-deficiency anemia ... all types of anemia . Signs and Symptoms of Anemia The most common symptom of all types of ...

  19. Iron Stain on Wood

    Science.gov (United States)

    Mark Knaebe

    2013-01-01

    Iron stain, an unsightly blue–black or gray discoloration, can occur on nearly all woods. Oak, redwood, cypress, and cedar are particularly prone to iron stain because these woods contain large amounts of tannin-like extractives. The discoloration is caused by a chemical reaction between extractives in the wood and iron in steel products, such as nails, screws, and...

  20. Iron-Deficiency Anemia

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    Full Text Available ... page from the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a ... Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented ...

  1. Iron-Deficiency Anemia

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    Full Text Available ... iron-rich foods in the diet. Too much milk also may prevent children's bodies from absorbing iron from other foods. Children who have lead in their blood also may be at risk for iron-deficiency anemia. Lead can interfere with the body's ability to make hemoglobin. Lead may get into the body from ...

  2. Iron-Deficiency Anemia

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    Full Text Available ... Tumblr. Share this page from the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency ... Iron-Deficiency Anemia article. Updated: March 26, 2014 Twitter Facebook YouTube Google+ SITE INDEX ACCESSIBILITY PRIVACY STATEMENT ...

  3. Iron-Deficiency Anemia

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    Full Text Available ... Site Health Topics News & Resources Intramural Research ... Is Iron-deficiency anemia is a common, easily treated condition that occurs if you don't have enough iron in your body. Low iron levels usually are due to blood loss, ...

  4. Iron-Deficiency Anemia

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    Full Text Available ... other dark green leafy vegetables Prune juice The Nutrition Facts labels on packaged foods will show how much iron the items contain. The amount is given as a percentage of the total amount of iron you need every day. Vitamin C Vitamin C helps the body absorb iron. ...

  5. Iron-Deficiency Anemia

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    Full Text Available ... the NHLBI on Twitter. What Is Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily ... Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the ...

  6. Iron homeostasis during pregnancy.

    Science.gov (United States)

    Fisher, Allison L; Nemeth, Elizabeta

    2017-12-01

    During pregnancy, iron needs to increase substantially to support fetoplacental development and maternal adaptation to pregnancy. To meet these iron requirements, both dietary iron absorption and the mobilization of iron from stores increase, a mechanism that is in large part dependent on the iron-regulatory hormone hepcidin. In healthy human pregnancies, maternal hepcidin concentrations are suppressed in the second and third trimesters, thereby facilitating an increased supply of iron into the circulation. The mechanism of maternal hepcidin suppression in pregnancy is unknown, but hepcidin regulation by the known stimuli (i.e., iron, erythropoietic activity, and inflammation) appears to be preserved during pregnancy. Inappropriately increased maternal hepcidin during pregnancy can compromise the iron availability for placental transfer and impair the efficacy of iron supplementation. The role of fetal hepcidin in the regulation of placental iron transfer still remains to be characterized. This review summarizes the current understanding and addresses the gaps in knowledge about gestational changes in hematologic and iron variables and regulatory aspects of maternal, fetal, and placental iron homeostasis. © 2017 American Society for Nutrition.

  7. Iron-Deficiency Anemia

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    Full Text Available ... have severe anemia, your doctor may recommend iron therapy. For this treatment, iron is injected into a muscle or an IV line in one of your blood vessels. IV iron therapy presents some safety concerns. It must be done ...

  8. Iron-Deficiency Anemia

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    Full Text Available ... blood transfusions , iron injections, or intravenous iron therapy. Rate This Content: NEXT >> Featured Video Living With and Managing Iron-Deficiency Anemia 05/18/2011 This video—presented by the National Heart, Lung, and Blood Institute, part of the National ...

  9. Iron-Deficiency Anemia

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    Full Text Available ... the body. Iron-deficiency anemia usually develops over time if your body doesn't have enough iron ... Institutes of Health—shows how Susan, a full-time worker and student, has coped with having iron- ...

  10. Iron-Deficiency Anemia

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    Full Text Available ... iron-deficiency anemia, especially if they have: A history of iron-deficiency anemia Heavy blood loss during their monthly periods Other risk factors for iron-deficiency anemia The Centers for Disease Control and Prevention (CDC) has developed guidelines for who ...

  11. Thermal Plasma Synthesis of Superparamagnetic Iron Oxide Nanoparticles

    NARCIS (Netherlands)

    Lei, P.Y.; Boies, A.M.; Calder, S.A.; Girshick, S.L.

    2012-01-01

    Superparamagnetic iron oxide nanoparticles were synthesized by injecting ferrocene vapor and oxygen into an argon/helium DC thermal plasma. Size distributions of particles in the reactor exhaust were measured online using an aerosol extraction probe interfaced to a scanning mobility particle sizer,

  12. Dietary iron-loaded rat liver haemosiderin and ferritin: in situ measurement of iron core nanoparticle size and cluster structure using anomalous small-angle x-ray scattering

    Science.gov (United States)

    Bovell, Eliza; Buckley, Craig E.; Chua-anusorn, Wanida; Cookson, David; Kirby, Nigel; Saunders, Martin; St. Pierre, Timothy G.

    2009-03-01

    The morphology, particle size distribution and cluster structure of the hydrated iron(III) oxyhydroxide particles associated with haemosiderin and ferritin in dietary iron-loaded rat liver tissue have been investigated using transmission electron microscopy (TEM) and anomalous small-angle x-ray scattering (ASAXS). Rat liver tissue was removed from a series of female Porton rats which had been fed an iron-rich diet until sacrifice at various ages from 2-24 months. Hepatic iron concentrations ranged from 1 to 65 mg Fe g-1 dry tissue. TEM studies showed both dispersed and clustered iron-containing nanoparticles. The dispersed particles were found to have mean sizes (±standard deviation) of 54 ± 8 Å for the iron-loaded animals and 55 ± 7 Å for the controls. Superposition of particles in TEM images prevented direct measurement of nanoparticulate size in the clusters. The ASAXS data were modelled to provide a quantitative estimate of both the size and spacing of iron oxyhydroxide particles in the bulk samples. The modelling yielded close-packed particles with sizes of 60 to 78 Å which when corrected for anomalous scattering suggests sizes from 54 to 70 Å. Particle size distributions are of particular importance since they determine the surface iron to core iron ratios, which in turn are expected to be related to the molar toxicity of iron deposits in cells.

  13. Fabrication of Iron-Containing Carbon Materials From Graphite Fluoride

    Science.gov (United States)

    Hung, Ching-cheh

    1996-01-01

    Carbon materials containing iron alloy, iron metal, iron oxide or iron halide were fabricated. Typical samples of these metals were estimated to contain 1 iron atom per 3.5 to 5 carbon atoms. Those carbon materials containing iron alloy, iron metal, and/or Fe3O4 were magnetic. The kinetics of the fabrication process were studied by exposing graphite fluoride (CF(0.68)) to FeCl3 over a 280 to 420 C temperature range. Between 280 and 295 C, FeCl3 quickly entered the structure of CF(0.68), broke the carbon-fluorine bonds, and within 10 to 30 min, completely converted it to carbon made up of graphite planes between which particles of crystalline FeF3 and noncrystalline FeCl3 were located. Longer reaction times (e.g., 28 hr) or higher reaction temperatures (e.g., 420 C) produced materials containing graphite, a FeCl3-graphite intercalation compound, FeCl2(center dot)4H2O, and FeCl2(center dot)2H2O. These products were further heat treated to produce iron-containing carbon materials. When the heating temperature was kept in the 750 to 850 C range, and the oxygen supply was kept at the optimum level, the iron halides in the carbon structure were converted to iron oxides. Raising the heat to temperatures higher than 900 C reduced such iron oxides to iron metal. The kinetics of these reactions were used to suggest processes for fabricating carbon materials containing iron alloy. Such processes were then tested experimentally. In one of the successful trial runs, commercially purchased CF(0.7) powder was used as the reactant, and NiO was added during the final heating to 1200 C as a source of both nickel and oxygen. The product thus obtained was magnetic and was confirmed to be a nickel-iron alloy in carbon.

  14. Magnetic Properties of Nanometer-sized Crystalline and Amorphous Particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Bødker, Franz; Hansen, Mikkel Fougt

    1997-01-01

    are superparamagnetic at finite temperatures. The temperature dependence of the superparamagnetic relaxation time and the influence of inter-particle interactions is discussed. Finally, some examples of studies of surface magnetization of alpha-Fe particles are presented.......Amorphous transition metal-metalloid alloy particles can be prepared by chemical preparation techniques. We discuss the preparation of transition metal-boron and iron-carbon particles and their magnetic properties. Nanometer-sized particles of both crystalline and amorphous magnetic materials...

  15. Using Iron to Treat Chlorohydrocarbon-Contaminated Soil

    Science.gov (United States)

    Hitchens, G. Duncan; Hodko, Dalibor; Kim, Heekyung; Rogers, Tom; Singh, Waheguru Pal; Giletto, Anthony; Cisar, Alan

    2004-01-01

    A method of in situ remediation of soil contaminated with chlorinated hydrocarbon solvents involves injection of nanometer-size iron particles. The present method exploits a combination of prompt chemical remediation followed by longer-term enhanced bioremediation and, optionally, is practiced in conjunction with the method of bioremediation described earlier. Newly injected iron particles chemically reduce chlorinated hydrocarbons upon contact. Thereafter, in the presence of groundwater, the particles slowly corrode via chemical reactions that effect sustained release of dissolved hydrogen. The hydrogen serves as an electron donor, increasing the metabolic activity of the anaerobic bacteria and thereby sustaining bioremediation at a rate higher than the natural rate.

  16. Radiation effects on iron-based superconductors

    Science.gov (United States)

    Eisterer, M.

    2018-01-01

    This article reviews the results of irradiation experiments on iron-based superconductors, with particular emphasis on neutron irradiation. These experiments were either done to foster the theoretical understanding of superconductivity in these compounds by investigating the influence of impurity scattering on the fundamental superconducting properties or to investigate vortex physics and to benchmark flux pinning in view of applications. Results on the most explored iron-based compounds are summarized and compared with data on metallic superconductors, cuprates, and MgB2. Similarities and differences are discussed as well as the influence of the type and energy of the particles used for the experiments.

  17. Mapping of cellular iron using hyperspectral fluorescence imaging in a cellular model of Parkinson's disease

    Science.gov (United States)

    Oh, Eung Seok; Heo, Chaejeong; Kim, Ji Seon; Lee, Young Hee; Kim, Jong Min

    2013-05-01

    Parkinson's disease (PD) is characterized by progressive dopaminergic cell loss in the substantianigra (SN) and elevated iron levels demonstrated by autopsy and with 7-Tesla magnetic resonance imaging. Direct visualization of iron with live imaging techniques has not yet been successful. The aim of this study is to visualize and quantify the distribution of cellular iron using an intrinsic iron hyperspectral fluorescence signal. The 1-methyl-4-phenylpyridinium (MPP+)-induced cellular model of PD was established in SHSY5Y cells. The cells were exposed to iron by treatment with ferric ammonium citrate (FAC, 100 μM) for up to 6 hours. The hyperspectral fluorescence imaging signal of iron was examined usinga high- resolution dark-field optical microscope system with signal absorption for the visible/ near infrared (VNIR) spectral range. The 6-hour group showed heavy cellular iron deposition compared with the small amount of iron accumulation in the 1-hour group. The cellular iron was dispersed in a small, particulate form, whereas extracellular iron was detected in an aggregated form. In addition, iron particles were found to be concentrated on the cell membrane/edge of shrunken cells. The cellular iron accumulation readily occurred in MPP+-induced cells, which is consistent with previous studies demonstrating elevated iron levels in the SN in PD. This direct iron imaging methodology could be applied to analyze the physiological role of iron in PD, and its application might be expanded to various neurological disorders involving other metals, such as copper, manganese or zinc.

  18. Implication of surface modified NZVI particle retention in the porous ...

    Indian Academy of Sciences (India)

    Retention of surface-modified nanoscale zero-valent iron (NZVI) particles in the porous media near the point of injection has been reported in the recent studies. Retention of excess particles in porous media can alter the media properties. The main objectives of this study are, therefore, to evaluate the effect of particle ...

  19. Iron homeostasis: An anthropocentric perspective.

    Science.gov (United States)

    Coffey, Richard; Ganz, Tomas

    2017-08-04

    The regulation of iron metabolism in biological systems centers on providing adequate iron for cellular function while limiting iron toxicity. Because mammals cannot excrete iron, mechanisms have evolved to control iron acquisition, storage, and distribution at both systemic and cellular levels. Hepcidin, the master regulator of iron homeostasis, controls iron flows into plasma through inhibition of the only known mammalian cellular iron exporter ferroportin. Hepcidin is feedback-regulated by iron status and strongly modulated by inflammation and erythropoietic demand. This review highlights recent advances that have changed our understanding of iron metabolism and its regulation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Iron Powder Treated Gray Irons: Critical Shape Characteristics for Graphite Nuclei

    Science.gov (United States)

    Stan, Stelian; Chisamera, Mihai; Riposan, Iulian; Ivan, Nicoleta; Barstow, Michael

    2012-08-01

    A program was conducted to research how to characterize the size and shape of micro-particles. These can act as graphite nuclei, but are altered by adding a commercial iron powder, or after a similar treatment combined with inoculation. Resin sand mold (RSM) and metal mold (MM) solidified sample structures were subjected to automatic image analysis. In general, a higher cooling rate, typical for MM solidification, favors smaller size and more compact particles, even in RSM media. Iron powder treatment led to the largest particles with unusual morphologies, better defined by complex shape factors, which employ actual perimeters, rather than the simpler median size and aspect ratio method. Conventional inoculation employed after an iron powder treatment altered the particles (smaller and more compact), which benefited their effectiveness to act as graphite nuclei, especially at slower solidification rates in RSMs. The results confirm that promoting more compact micro-inclusions, at smaller sizes, involved in graphite nucleation, reduces the sensitivity to chill and improves the eutectic cell characteristics in gray cast iron.

  1. The production of magnetic nanoparticles of Iron Oxide by arc discharge in water

    Science.gov (United States)

    Yousefi, Hamid Reza; Fathollah, Sara; Nikeyn, Maryam; Khatami, Shohreh

    2012-10-01

    Nanoparticles can be utilized for any practical application. In recent years; considerable attention has been paid to iron oxide magnetic. Iron oxide nanoparticles are the class of nanoparticle which can have useful magnetic properties. In this research, magnetic iron oxide nanoparticles were produced by Arc discharge method in water. Structural analysis carried out by X-ray diffraction analysis (XRD), Scanning Electron Microscopy (SEM), and Spectrophotometer. Various magnetic nanoparticles like iron carbide (Fe3c), magnetic iron oxide (magnetite /maghemite) are obtained by arc discharge method in water. In this work have been showed, the influence of the time duration on the number of magnetic nanoparticles and the influence of the gap between the two electrodes on particle structure and size distribution. Furthermore, when iron nanoparticles are used under applied magnetic field, the particles would move in the direction of magnetic field. When the magnetic field is removed, the particles stop moving and still remain stably suspend in the dielectric liquid.

  2. Dust deposition: iron source or sink? A case study

    Directory of Open Access Journals (Sweden)

    Y. Ye

    2011-08-01

    Full Text Available A significant decrease of dissolved iron (DFe concentration has been observed after dust addition into mesocosms during the DUst experiment in a low Nutrient low chlorophyll Ecosystem (DUNE, carried out in the summer of 2008. Due to low biological productivity at the experiment site, biological consumption of iron can not explain the magnitude of DFe decrease. To understand processes regulating the observed DFe variation, we simulated the experiment using a one-dimensional model of the Fe biogeochemical cycle, coupled with a simple ecosystem model. Different size classes of particles and particle aggregation are taken into account to describe the particle dynamics. DFe concentration is regulated in the model by dissolution from dust particles and adsorption onto particle surfaces, biological uptake, and photochemical mobilisation of particulate iron.

    The model reproduces the observed DFe decrease after dust addition well. This is essentially explained by particle adsorption and particle aggregation that produces a high export within the first 24 h. The estimated particle adsorption rates range between the measured adsorption rates of soluble iron and those of colloidal iron, indicating both processes controlling the DFe removal during the experiment. A dissolution timescale of 3 days is used in the model, instead of an instantaneous dissolution, underlining the importance of dissolution kinetics on the short-term impact of dust deposition on seawater DFe.

    Sensitivity studies reveal that initial DFe concentration before dust addition was crucial for the net impact of dust addition on DFe during the DUNE experiment. Based on the balance between abiotic sinks and sources of DFe, a critical DFe concentration has been defined, above which dust deposition acts as a net sink of DFe, rather than a source. Taking into account the role of excess iron binding ligands and biotic processes, the critical DFe concentration might be applied to

  3. Sedimentary and mineral dust sources of dissolved iron to the world ocean

    Directory of Open Access Journals (Sweden)

    J. K. Moore

    2008-05-01

    Full Text Available Analysis of a global compilation of dissolved-iron observations provides insights into the processes controlling iron distributions and some constraints for ocean biogeochemical models. The distribution of dissolved iron appears consistent with the conceptual model developed for Th isotopes, whereby particle scavenging is a two-step process of scavenging mainly by colloidal and small particulates, followed by aggregation and removal on larger sinking particles. Much of the dissolved iron (<0.4 μm is present as small colloids (>~0.02 μm and, thus, is subject to aggregation and scavenging removal. This implies distinct scavenging regimes for dissolved iron consistent with the observations: 1 a high scavenging regime – where dissolved-iron concentrations exceed the concentrations of strongly binding organic ligands; and 2 a moderate scavenging regime – where dissolved iron is bound to both colloidal and soluble ligands. Within the moderate scavenging regime, biological uptake and particle scavenging decrease surface iron concentrations to low levels (<0.2 nM over a wide range of low to moderate iron input levels. Removal rates are also highly nonlinear in areas with higher iron inputs. Thus, observed surface-iron concentrations exhibit a bi-modal distribution and are a poor proxy for iron input rates. Our results suggest that there is substantial removal of dissolved iron from subsurface waters (where iron concentrations are often well below 0.6 nM, most likely due to aggregation and removal on sinking particles of Fe bound to organic colloids.

    We use the observational database to improve simulation of the iron cycle within a global-scale, Biogeochemical Elemental Cycling (BEC ocean model. Modifications to the model include: 1 an improved particle scavenging parameterization, based on the sinking mass flux of particulate organic material, biogenic silica, calcium carbonate, and mineral dust particles; 2 desorption of dissolved iron

  4. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-06-01

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

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

    Science.gov (United States)

    2010-09-01

    value nZVI nano -scale ZVI O&M operation and maintenance ORP oxidation-reduction potential P&T pump -and-treat PCE tetrachloroethene PRB...grade surfactant, biodegradable oil, water, and ZVI particles (either nano - or micro -scale iron, nZVI, or mZVI), which form emulsion particles. The...is composed of food- grade surfactant, biodegradable oil, water, and ZVI particles (either nano - or micro -scale iron, nZVI, or mZVI), which form

  6. Biological Properties of Iron Oxide Nanoparticles for Cellular and Molecular Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Claus-Christian Glüer

    2010-12-01

    Full Text Available Superparamagnetic iron-oxide particles (SPIO are used in different ways as contrast agents for magnetic resonance imaging (MRI: Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite, different coatings (none, dextran, carboxydextran, polystyrene and different hydrodynamic diameters (20–850 nm for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC, which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe3O4 particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.

  7. A large proportion of asymptomatic Plasmodium infections with low and sub-microscopic parasite densities in the low transmission setting of Temotu Province, Solomon Islands: challenges for malaria diagnostics in an elimination setting

    Directory of Open Access Journals (Sweden)

    Harris Ivor

    2010-09-01

    Full Text Available Abstract Background Many countries are scaling up malaria interventions towards elimination. This transition changes demands on malaria diagnostics from diagnosing ill patients to detecting parasites in all carriers including asymptomatic infections and infections with low parasite densities. Detection methods suitable to local malaria epidemiology must be selected prior to transitioning a malaria control programme to elimination. A baseline malaria survey conducted in Temotu Province, Solomon Islands in late 2008, as the first step in a provincial malaria elimination programme, provided malaria epidemiology data and an opportunity to assess how well different diagnostic methods performed in this setting. Methods During the survey, 9,491 blood samples were collected and examined by microscopy for Plasmodium species and density, with a subset also examined by polymerase chain reaction (PCR and rapid diagnostic tests (RDTs. The performances of these diagnostic methods were compared. Results A total of 256 samples were positive by microscopy, giving a point prevalence of 2.7%. The species distribution was 17.5% Plasmodium falciparum and 82.4% Plasmodium vivax. In this low transmission setting, only 17.8% of the P. falciparum and 2.9% of P. vivax infected subjects were febrile (≥38°C at the time of the survey. A significant proportion of infections detected by microscopy, 40% and 65.6% for P. falciparum and P. vivax respectively, had parasite density below 100/μL. There was an age correlation for the proportion of parasite density below 100/μL for P. vivax infections, but not for P. falciparum infections. PCR detected substantially more infections than microscopy (point prevalence of 8.71%, indicating a large number of subjects had sub-microscopic parasitemia. The concordance between PCR and microscopy in detecting single species was greater for P. vivax (135/162 compared to P. falciparum (36/118. The malaria RDT detected the 12 microscopy and

  8. Particle detectors

    CERN Multimedia

    CERN. Geneva

    1999-01-01

    Introduction, interaction of radiation with matter measurement of momentum of charged particles, of energy of e/gamma, hadrons, identification of particles. Design of HEP detectors. Principle of operation and performance of tracking sub-detectors, calorimeters and muon system.

  9. THE EFFECT OF SMECTITE ON THE CORROSION OF IRON METAL

    Energy Technology Data Exchange (ETDEWEB)

    Balko, Barbara A.; Bosse, Stephanie A.; Cade, Anne E.; Jones-Landry, Elise F.; Amonette, James E.; Daschbach, John L.

    2012-04-24

    The combination of zero-valent iron and a clay-type amendment is often observed to have a synergistic effect on the rate of reduction reactions. In this paper, electrochemical techniques are used to determine the mechanism of interaction between the iron and smectite clay minerals. Iron electrodes coated with an evaporated smectite suspension (clay-modified iron electrodes, CMIEs) were prepared using five different smectites: SAz-1, SWa-1, STx-1, SWy-1, and SHCa-1. All the smectites were exchanged with Na+ and one sample of SWy-1 was also exchanged with Mg2+. Potentiodynamic potential scans and cyclic voltammograms were taken using the CMIEs and uncoated but passivated iron electrodes. These electrochemical experiments, along with measurements of the amount of Fe2+ and Fe3+ sorbed in the smectite coating, suggested that the smectite removed the passive layer of the underlying iron electrode during the evaporation process. Cyclic voltammograms taken after the CMIEs were biased at the active-passive transition potential for varying amounts of time suggested that the smectite limited growth of a passive layer, preventing passivation. These results are attributed to the Broensted acidity of the smectite as well as to its ability to sorb iron cations. Oxides that did form on the surface of the iron in the presence of the smectite when it was biased anodically seemed to be different than those that form on the surface of an uncoated iron electrode under otherwise similar conditions; this difference suggested that the smectite reacted with the Fe2+ formed from the oxidation of the underlying iron. No significant correlation could be found between the ability of the smectite to remove the iron passive film and the smectite type. The results have implications for the mixing of sediments and iron particles in permeable reactive barriers, underground storage of radioactive waste in steel canisters, and the use of smectite supports in preventing aggregation of nano-sized zero

  10. Magnetic particle imaging an introduction to imaging principles and scanner instrumentation

    CERN Document Server

    Knopp, Tobias

    2012-01-01

    This is an overview of recent progress in magnetic particle imaging, which uses various static and oscillating magnetic fields and tracer materials made from iron oxide nanoparticles to perform background-free measurements of the particles' local concentration.

  11. Mineralogy and geochemistry of banded iron formation and iron ...

    Indian Academy of Sciences (India)

    The geological complexities of banded iron formation (BIF) and associated iron ores of Jilling–Langalata iron ore deposits, Singhbhum–North Orissa Craton, belonging to Iron Ore Group (IOG) eastern India have been studied in detail along with the geochemical evaluation of different iron ores. The geochemical and ...

  12. Liver Iron Contents in Rats after Administration of Certain Iron ...

    African Journals Online (AJOL)

    Liver Iron Contents in Rats after Administration of Certain Iron Compounds. CP van Wyk, DJ Robbins. Abstract. The effect of consumption of certain iron compounds on liver iron deposition was studied in rats, in each case at 4 dietary iron levels ranging from 70 to 206 mg/100 g diet. In one of two series the basic diet was ...

  13. Hyperspectral fluorescence imaging for cellular iron mapping in the in vitro model of Parkinson's disease

    Science.gov (United States)

    Oh, Eung Seok; Heo, Chaejeong; Kim, Ji Seon; Suh, Minah; Lee, Young Hee; Kim, Jong-Min

    2014-05-01

    Parkinson's disease (PD) is characterized by progressive dopaminergic cell loss in the substantia nigra (SN) and elevated iron levels demonstrated by autopsy. Direct visualization of iron with live imaging techniques has not yet been successful. The aim of this study is to visualize and quantify the distribution of cellular iron using an intrinsic iron hyperspectral fluorescence signal. The 1-methyl-4-phenylpyridinium (MPP+)-induced cellular model of PD was established in SHSY5Y cells exposed to iron with ferric ammonium citrate (FAC, 100 μM). The hyperspectral fluorescence signal of iron was examined using a high-resolution dark-field optical microscope system with signal absorption for the visible/near infrared spectral range. The 6-h group showed heavy cellular iron deposition compared with the 1-h group. The cellular iron was dispersed in a small particulate form, whereas the extracellular iron was aggregated. In addition, iron particles were found to be concentrated on the cell membrane/edge of shrunken cells. The iron accumulation readily occurred in MPP+-induced cells, which is consistent with previous studies demonstrating elevated iron levels in the SN. This direct iron imaging could be applied to analyze the physiological role of iron, and its application might be expanded to various neurological disorders involving metals, such as copper, manganese, or zinc.

  14. Environmental application of millimetre-scale sponge iron (s-Fe0) particles (IV): New insights into visible light photo-Fenton-like process with optimum dosage of H2O2 and RhB photosensitizers.

    Science.gov (United States)

    Ju, Yongming; Yu, Yunjiang; Wang, Xiaoyan; Xiang, Mingdeng; Li, Liangzhong; Deng, Dongyang; Dionysiou, Dionysios D

    2017-02-05

    In this study, we firstly develop the photo-Fenton-like system with millimetric sponge iron (s-Fe0), H2O2, visible light (vis, λ≥420nm) and rhodamine B (RhB), and present a comprehensive study concerning the mechanism. Thus, we investigate (1) the adsorption of RhB onto s-Fe0, (2) the photo-Fenton-like removal of RhB over iron oxides generated from the corrosion of s-Fe0, (3) the homogeneous photo-Fenton removal of RhB over Fe2+ or Fe3+, (4) the Fe3+-RhB complexes, and (5) the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). The results show that neither the adsorption process over s-Fe0 nor the photo-Fenton-like process over FeOOH, Fe3O4 and Fe2O3, achieved efficient removal of RhB. For comparison, in homogeneous photo-Fenton process, the presence of Fe3+ ions, rather than Fe2+ ions, effectively eliminated RhB. Furthermore, the UV-vis spectra showing new absorbance at∼285nm indicate the complexes of RhB and Fe3+ ions, adopting vis photons to form excited state and further eject one electron via ligand-to-metal charge-transfer to activate H2O2. Additionally, efficient TBBPA removal was obtained only in the presence of RhB. Accordingly, the s-Fe0- based photo-Fenton-like process assisted with dyestuff wastewater is promising for removing a series of persistent organic pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Biogeochemical Recycling on Aerosol Particles

    Science.gov (United States)

    Arimoto, R.; Stewart, B.; Khaing, H.; Tatro, D. P.

    2006-12-01

    Trace elements are recycled on sea-salt particles that are produced and later re-deposited in the surface ocean. This recycling process involves aluminum, iron, and other elements commonly associated with mineral dust. Non-crustal Al can amount to as much as ~ 30% of the total aerosol Al at Bermuda, but this occurs only during a few months of the year when the dust concentrations and deposition rates are low. Simple model calculations suggest that ~15 to 20% of the total Al dry deposition during December and January can be attributed to recycled sea salt, but when dust concentrations are higher, recycling accounts for only ~ 1% of the Al dry deposition. Non-crustal/non-sea salt (NC/NSS) sources account for > 70% of the aerosol Sb, Se, V, and Zn, but differences in the dry deposition velocities for particles of different sizes are such that the amount of Sb and Se recycled on sea spray approaches or exceeds their new inputs to the open ocean from dust and the NC/NSS sources. More recently, recycling on aerosol particles has been found to occur in other environments, including the deserts in the southwestern USA. In this case, the recycling of radionuclides released during nuclear weapons tests many years ago occurs via the resuspension of contaminated soil particles. Studies conducted near Carlsbad, NM have shown that the temporal variability in ^{239,240}Pu and ^{241}Am activities tracks that of Al, a mineral dust indictor, in aerosol samples. Analyses of soil samples from various sites have shown that plutonium is released from the particles by chemical procedures developed for removing iron oxides from mineral particles; this implies that the dust/plutonium relationship is mediated by iron oxides.

  16. State of the iron

    DEFF Research Database (Denmark)

    Reinisch, Walter; Staun, Michael; Bhandari, Sunil

    2013-01-01

    Iron deficiency anemia (IDA) frequently occurs in patients suffering from inflammatory bowel disease (IBD) and negatively impacts their quality of life. Nevertheless, the condition appears to be both under-diagnosed and undertreated. Regular biochemical screening of patients with IBD for anemia...... by the gastroenterology community has to be advocated. Oral iron is a low cost treatment however its effectiveness is limited by low bioavailability and poor tolerability. Intravenous (IV) iron rapidly replenishes iron stores and has demonstrated its safe use in a number of studies in various therapeutic areas. A broad...... spectrum of new IV iron formulations is now becoming available offering improved tolerability and patient convenience by rapidly restoring the depleted iron status of patients with IBD. The following article aims to review the magnitude of the problem of IDA in IBD, suggest screening standards...

  17. Iron content of food cooked in iron utensils.

    Science.gov (United States)

    Brittin, H C; Nossaman, C E

    1986-07-01

    Twenty foods were cooked in iron and non-iron utensils. Also, three foods were cooked in two iron skillets. Three replications were made, and cooking time and pH for each food were determined. Duplicate samples of the raw and the cooked foods were dried, ashed, and analyzed for moisture and iron content. Iron content was determined by atomic absorption spectrophotometry. Most of the foods (90%) contained significantly more iron when cooked in iron utensils than when cooked in non-iron utensils. Acidity, moisture content, and cooking time of food significantly affected the iron content of food cooked in iron utensils. Perhaps because of differing amounts of previous use, cooking in different iron skillets resulted in some variation in the iron content of food.

  18. Physics of iron

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, O.

    1993-10-01

    This volume comprises papers presented at the AIRAPT Conference, June 28 to July 1993. The iron sessions at the meeting were identified as the Second Ironworkers Convention. The renewal of interest stems from advances in technologies in both diamond-anvil cell (DAC) and shock wave studies as well as from controversies arising from a lack of consensus among both experimentalists and theoreticians. These advances have produced new data on iron in the pressure-temperature regime of interest for phase diagrams and for temperatures of the core/mantle and inner-core/outer-core boundaries. Particularly interesting is the iron phase diagram inferred from DAC studies. A new phase, {beta}, with a {gamma}-{beta}-{epsilon} triple point at about 30 GPa and 1190 K, and possible sixth phase, {omega}, with an {epsilon}-{Theta}-melt triple point at about 190 GPa and 4000 K are deemed possible. The importance of the equation of state of iron in consideration of Earth`s heat budget and the origin of its magnetic field invoke the interest of theoreticians who argue on the basis of molecular dynamics and other first principles methods. While the major thrust of both meetings was on the physics of pure iron, there was notable contributions on iron alloys. Hydrogen-iron alloys, iron-sulfur liquids, and the comparability to rhenium in phase diagram studies are discussed. The knowledge of the physical properties of iron were increased by several contributions.

  19. Polygamous particles.

    Science.gov (United States)

    Wu, Kun-Ta; Feng, Lang; Sha, Ruojie; Dreyfus, Rémi; Grosberg, Alexander Y; Seeman, Nadrian C; Chaikin, Paul M

    2012-11-13

    DNA is increasingly used as an important tool in programming the self-assembly of micrometer- and nanometer-scale particles. This is largely due to the highly specific thermoreversible interaction of cDNA strands, which, when placed on different particles, have been used to bind precise pairs in aggregates and crystals. However, DNA functionalized particles will only reach their true potential for particle assembly when each particle can address and bind to many different kinds of particles. Indeed, specifying all bonds can force a particular designed structure. In this paper, we present the design rules for multiflavored particles and show that a single particle, DNA functionalized with many different "flavors," can recognize and bind specifically to many different partners. We investigate the cost of increasing the number of flavors in terms of the reduction in binding energy and melting temperature. We find that a single 2-μm colloidal particle can bind to 40 different types of particles in an easily accessible time and temperature regime. The practical limit of ∼100 is set by entropic costs for particles to align complementary pairs and, surprisingly, by the limited number of distinct "useful" DNA sequences that prohibit subunits with nonspecific binding. For our 11 base "sticky ends," the limit is 73 distinct sequences with no unwanted overlaps of 5 bp or more. As an example of phenomena enabled by polygamous particles, we demonstrate a three-particle system that forms a fluid of isolated clusters when cooled slowly and an elastic gel network when quenched.

  20. Rapid decolorization of textile wastewater by green synthesized iron nanoparticles.

    Science.gov (United States)

    Ozkan, Z Y; Cakirgoz, M; Kaymak, E S; Erdim, E

    2018-01-01

    The effectiveness of green tea (Camellia sinensis) and pomegranate (Punica granatum) extracts for the production of iron nanoparticles and their application for color removal from a textile industry wastewater was investigated. Polyphenols in extracts act as reducing agents for iron ions in aqueous solutions, forming iron nanoparticles. Pomegranate extract was found to have almost a 10-fold higher polyphenolic content than the same amount of green tea extract on a mass basis. However, the size of the synthesized nanoparticles did not show a correlation with the polyphenolic content. 100 ppm and 300 ppm of iron nanoparticles were evaluated in terms of color removal efficiency from a real textile wastewater sample. 300 ppm of pomegranate nanoscale zero-valent iron particles showed more than 95% color removal and almost 80% dissolved organic carbon removal. The degradation mechanisms are is considered to be adsorption and precipitation to a major extent, and mineralization to a minor extent.

  1. Iron Refractory Iron Deficiency Anaemia: A Rare Cause of Iron Deficiency Anaemia

    LENUS (Irish Health Repository)

    McGrath, T

    2018-01-01

    We describe the case of a 17-month-old boy with a hypochromic microcytic anaemia, refractory to oral iron treatment. After exclusion of dietary and gastrointestinal causes of iron deficiency, a genetic cause for iron deficiency was confirmed by finding two mutations in the TMPRSS6 gene, consistent with a diagnosis of iron-refractory iron deficiency anaemia (IRIDA).

  2. Behavior of magnetorheological elastomers with coated particles

    Science.gov (United States)

    Behrooz, Majid; Sutrisno, Joko; Zhang, Lingyue; Fuchs, Alan; Gordaninejad, Faramarz

    2015-03-01

    Iron particle coating can improve the behavior of magnetorheological elastomers (MREs) by inhibiting iron particle rusting; however, such a process can change physical properties of MREs such as oxidation resistance, shear modulus, and stiffness change due to an applied magnetic field. In this study, MRE samples are fabricated with regular and polymerized iron particles. To investigate the possibility and extent of these changes, polymerized particle MRE samples are made using a combination of reversible addition fragmentation chain transfer and click chemistry. Shear test sample MREs with pure elastomer and 50 wt% MRE with and without polymerization are fabricated. To observe the effect of oxidation on shear properties of MREs, pure elastomer and 50 wt% coated and non-coated samples are oxidized using accelerated oxidation procedure. Experimental results show that oxidation significantly reduces the shear modulus of the elastomer matrix. The coating process of iron particles does not significantly change the shear modulus of resulting MREs but reduces the loss of shear modulus due to oxidation.

  3. Investigation of the physical properties of iron nanoparticles in the course of the melting and solidification

    Science.gov (United States)

    Fedorov, A. V.; Shul'gin, A. V.; Lavruk, S. A.

    2017-06-01

    The processes of iron-nanoparticles melting and iron-nanodroes solidification have been studied under different thermal actions. The determined values of the phase-transition temperatures for particles with radii of 1.5-4 nm agree with the data calculated by other authors. In the course of calculating the solidification of iron nanoparticles, the dependence of the solidification temperature on the rate of heat removal has been found and the hysteresis of the phase transition has been demonstrated. Based on the determined caloric curves, the heat capacity of the particles has been found and their approximation in the form of dependences on temperature and particle size has been suggested.

  4. Super-iron Nanoparticles with Facile Cathodic Charge Transfer

    Energy Technology Data Exchange (ETDEWEB)

    M Farmand; D Jiang; B Wang; S Ghosh; D Ramaker; S Licht

    2011-12-31

    Super-irons contain the + 6 valence state of iron. One advantage of this is that it provides a multiple electron opportunity to store additional battery charge. A decrease of particle size from the micrometer to the nanometer domain provides a higher surface area to volume ratio, and opportunity to facilitate charge transfer, and improve the power, voltage and depth of discharge of cathodes made from such salts. However, super-iron salts are fragile, readily reduced to the ferric state, with both heat and contact with water, and little is known of the resultant passivating and non-passivating ferric oxide products. A pathway to decrease the super-iron particle size to the nano-domain is introduced, which overcomes this fragility, and retains the battery capacity advantage of their Fe(VI) valence state. Time and power controlled mechanosynthesis, through less aggressive, dry ball milling, leads to facile charge transfer of super-iron nanoparticles. Ex-situ X-ray Absorption Spectroscopy is used to explore the oxidation state and structure of these iron oxides during discharge and shows the significant change in stability of the ferrate structure to lower oxidation state when the particle size is in the nano-domain.

  5. Synthesis of iron nanoparticles from hemoglobin and myoglobin.

    Science.gov (United States)

    Sayyad, Arshad S; Balakrishnan, Kaushik; Ci, Lijie; Kabbani, Ahmad T; Vajtai, Robert; Ajayan, Pulickel M

    2012-02-10

    Stable iron nanoparticles have been synthesized from naturally occurring and abundant Fe-containing bio-precursors, namely hemoglobin and myoglobin. The formation of stable iron nanoparticles was achieved through a one-pot, single-phase chemical reduction approach. The reduction of iron ions present in the bio-precursors was carried out at room temperature and avoids the use of harsh chemical reagents. The size distribution of the product falls into the narrow 2-5 nm range and the particles were found to be crystalline. This method can be a valuable synthetic approach for producing bio-conjugated nanoparticle systems for biological applications.

  6. Zooplankton Gut Passage Mobilizes Lithogenic Iron for Ocean Productivity.

    Science.gov (United States)

    Schmidt, Katrin; Schlosser, Christian; Atkinson, Angus; Fielding, Sophie; Venables, Hugh J; Waluda, Claire M; Achterberg, Eric P

    2016-10-10

    Iron is an essential nutrient for phytoplankton, but low concentrations limit primary production and associated atmospheric carbon drawdown in large parts of the world's oceans [1, 2]. Lithogenic particles deriving from aeolian dust deposition, glacial runoff, or river discharges can form an important source if the attached iron becomes dissolved and therefore bioavailable [3-5]. Acidic digestion by zooplankton is a potential mechanism for iron mobilization [6], but evidence is lacking. Here we show that Antarctic krill sampled near glacial outlets at the island of South Georgia (Southern Ocean) ingest large amounts of lithogenic particles and contain 3-fold higher iron concentrations in their muscle than specimens from offshore, which confirms mineral dissolution in their guts. About 90% of the lithogenic and biogenic iron ingested by krill is passed into their fecal pellets, which contain ∼5-fold higher proportions of labile (reactive) iron than intact diatoms. The mobilized iron can be released in dissolved form directly from krill or via multiple pathways involving microbes, other zooplankton, and krill predators. This can deliver substantial amounts of bioavailable iron and contribute to the fertilization of coastal waters and the ocean beyond. In line with our findings, phytoplankton blooms downstream of South Georgia are more intensive and longer lasting during years with high krill abundance on-shelf. Thus, krill crop phytoplankton but boost new production via their nutrient supply. Understanding and quantifying iron mobilization by zooplankton is essential to predict ocean productivity in a warming climate where lithogenic iron inputs from deserts, glaciers, and rivers are increasing [7-10]. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Particle cosmology

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.

  8. Particle Physics

    CERN Document Server

    Martin, B R

    2008-01-01

    An essential introduction to particle physics, with coverage ranging from the basics through to the very latest developments, in an accessible and carefully structured text. Particle Physics: Third Edition is a revision of a highly regarded introduction to particle physics. In its two previous editions this book has proved to be an accessible and balanced introduction to modern particle physics, suitable for those students needed a more comprehensive introduction to the subject than provided by the 'compendium' style physics books. In the Third Edition the standard mod

  9. [Iron deficiency and digestive disorders].

    Science.gov (United States)

    Cozon, G J N

    2014-11-01

    Iron deficiency anemia still remains problematic worldwide. Iron deficiency without anemia is often undiagnosed. We reviewed, in this study, symptoms and syndromes associated with iron deficiency with or without anemia: fatigue, cognitive functions, restless legs syndrome, hair loss, and chronic heart failure. Iron is absorbed through the digestive tract. Hepcidin and ferroportin are the main proteins of iron regulation. Pathogenic micro-organisms or intestinal dysbiosis are suspected to influence iron absorption. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  10. Cristobalite and Hematite Particles in Human Brain.

    Science.gov (United States)

    Kopani, Martin; Kopaniova, A; Trnka, M; Caplovicova, M; Rychly, B; Jakubovsky, J

    2016-11-01

    Foreign substances get into the internal environment of living bodies and accumulate in various organs. Cristobalite and hematite particles in the glial cells of pons cerebri of human brain with diagnosis of Behhet disease with scanning electron microscopy (SEM), energy-dispersive microanalysis (EDX), and transmission electron microscopy (TEM) with diffraction were identified. SEM with EDX revealed the matter of irregular micrometer-sized particles sometimes forming polyhedrons with fibrilar or stratified structure. It was found in some particles Ti, Fe, and Zn. Some particles contained Cu. TEM and electron diffraction showed particles of cristobalite and hematite. The presence of the particles can be a result of environmental effect, disruption of normal metabolism, and transformation of physiologically iron-ferrihydrite into more stable form-hematite. From the size of particles can be drawn the long-term accumulation of elements in glial cells.

  11. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... your red blood cells don't contain enough hemoglobin (HEE-muh-glow-bin). Hemoglobin is an iron-rich protein that carries oxygen ... red blood cells it does make have less hemoglobin than normal. Iron-deficiency anemia can cause fatigue ( ...

  12. Thin Wall Iron Castings

    Energy Technology Data Exchange (ETDEWEB)

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  13. Taking iron supplements

    Science.gov (United States)

    ... your health care provider tell you how many pills you should take each day and when you should take them. Taking more iron than your body needs can cause serious medical problems. Blood counts return to normal after 2 months of iron therapy for most people. ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... babies need more iron as they grow and begin to eat solid foods. Talk with your child's ... C Vitamin C helps the body absorb iron. Good sources of vitamin C are ... or other severe health issues. For more information, go to the Health ...

  15. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... if you eat the right foods. For example, good nonmeat sources of iron include iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark green leafy vegetables. Eat poorly because of money, social, health, or other problems. Follow a very low-fat ...

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... also may help treat iron-deficiency anemia. Medical History Your doctor will ask about your signs and symptoms and any past problems you've had with anemia or low iron. He or she also may ask about your diet and whether you're taking any medicines. If ...

  17. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Blood Tests Blood Transfusion Restless Legs Syndrome Send a link to NHLBI to someone by E-MAIL | ... Iron-Deficiency Anemia? Español Iron-deficiency anemia is a common, easily treated condition that occurs if you ...

  18. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... shows how Susan, a full-time worker and student, has coped with having iron-deficiency anemia. Prior to her diagnosis, Susan had symptoms such as tiredness, poor skin tone, dizziness, and depression. After her doctor diagnosed her with iron-deficiency ...

  19. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... For more information about diet and supplements, go to "How Is Iron-Deficiency Anemia Treated?" Infants and young ... who should be screened for iron deficiency, and how often: Girls aged 12 to 18 and women of childbearing age who are ...

  20. Microbes: Mini Iron Factories

    National Research Council Canada - National Science Library

    Joshi, Kumar Batuk

    2014-01-01

    ... bog iron and ochre deposits. Here, we discuss the role that microbes have been playing in precipitation of iron and the role and importance of interdisciplinary studies in the field of geology and biology in solving some of the major geological mysteries.

  1. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Activity Population and Epidemiology Studies Women’s Health All Science A-Z ... usually are due to blood loss, poor diet, or an inability to absorb enough iron from food. Overview Iron-deficiency anemia is a common type ...

  2. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... Factors Infants and Young Children Infants and young children need a lot of iron to grow and develop. ... of cow's milk your baby drinks. Also, babies need more iron as they grow and begin to eat solid foods. Talk with your child's doctor about a healthy diet and food choices ...

  3. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... can lead to heart problems, infections, problems with growth and development in children, and other complications. Infants and young ... need for iron increases during these times of growth and development. Inability To Absorb Enough Iron Even if you ...

  4. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available Skip to main content U.S. Department of Health & Human ... anemia is a common, easily treated condition that occurs if you don't have enough iron in your body. Low iron levels usually are due to blood ...

  5. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... women of childbearing age has iron-deficiency anemia. Pregnant women also are at higher risk for the condition ... for the fetus' growth. About half of all pregnant women develop iron-deficiency anemia. The condition can increase ...

  6. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... also may have a blood test for a chemical called erythrocyte protoporphyrin. This chemical is a building block for hemoglobin. Children also ... foods that are rich in iron. The best source of iron is red meat, especially beef and ...

  7. 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

  8. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... have RLS often have a hard time sleeping. Iron-deficiency anemia can put children at greater risk for lead poisoning and infections. Some signs and symptoms of iron-deficiency anemia are related to the condition's causes. For ...

  9. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... food. Overview Iron-deficiency anemia is a common type of anemia . The term "anemia" usually refers to a condition ... symptoms of iron-deficiency anemia apply to all types of anemia . Signs and Symptoms of Anemia The most common ...

  10. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... will diagnose iron-deficiency anemia based on your medical history, a physical exam, and the results from tests and procedures. Once ... specialists also may help treat iron-deficiency anemia. Medical ... be pregnant. Physical Exam Your doctor will do a physical exam to ...

  11. Iron Sucrose Injection

    Science.gov (United States)

    ... finish your treatment, your doctor may prescribe this medication again.Iron sucrose injection may cause severe or life-threatening reactions while you receive the medication. Your doctor will watch you carefully while you ... of iron sucrose injection and for at least 30 minutes afterwards. Tell ...

  12. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... be advised. Treatments for Severe Iron-Deficiency Anemia Blood Transfusion If your iron-deficiency anemia is severe, you ... get a transfusion of red blood cells. A blood transfusion is a safe, common procedure in which blood ...

  13. Iron replacement therapy

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; Coskun, Mehmet; Weiss, Günter

    2016-01-01

    PURPOSE OF REVIEW: Approximately, one-third of the world's population suffers from anemia, and at least half of these cases are because of iron deficiency. With the introduction of new intravenous iron preparations over the last decade, uncertainty has arisen when these compounds should...... be administered and under which circumstances oral therapy is still an appropriate and effective treatment. RECENT FINDINGS: Numerous guidelines are available, but none go into detail about therapeutic start and end points or how iron-deficiency anemia should be best treated depending on the underlying cause...... of iron deficiency or in regard to concomitant underlying or additional diseases. SUMMARY: The study points to major issues to be considered in revisions of future guidelines for the true optimal iron replacement therapy, including how to assess the need for treatment, when to start and when to stop...

  14. The effect of cationic polymer treatment on adhesion of iron oxide to eyelashes.

    Science.gov (United States)

    Ko, S; Roh, Y H; Choo, J H; Jang, S H; Han, S H; Jang, H G

    2009-01-01

    The aim of this study was to investigate the effect of iron oxide application on improving the volume of eyelashes. Iron oxide, having a negative surface charge in its natural form, was coated with commercial cationic polymers to increase its adhesion. The iron oxides coated with different types and concentrations of these polymers were incorporated into a basic mascara formula to test their volume effects by means of the weight difference of eyelashes.The results indicated that the type and concentration of coating materials affect the surface zeta potential and particle cluster size of iron oxides. The type of cationic polymer, especially, was shown to modify both factors of iron oxide. The obtained results also suggested that the volume effect of mascara increases with a higher positive surface zeta potential and a smaller particle cluster size of the coated iron oxides.

  15. Particle physics

    CERN Document Server

    Carlsmith, Duncan

    2012-01-01

    Particle Physics is the first book to connect theory and experiment in particle physics. Duncan Carlsmith provides the first accessible exposition of the standard model with sufficient mathematical depth to demystify the language of gauge theory and Feynman diagrams used by researchers in the field. Carlsmith also connects theories to past, present, and future experiments.

  16. Orange peel + nanostructured zero-valent-iron composite for the removal of hexavalent chromium in water

    Science.gov (United States)

    Olea-Mejía, O.; Cabral-Prieto, A.; Salcedo-Castillo, U.; López-Tellez, G.; Olea-Cardoso, O.; López-Castañares, R.

    2017-11-01

    In this work we used the Pulsed Plasma in Liquid technique to synthesize zero-valent iron nanostructures. We used a DC Power Source to produce such plasma on water and methanol. The obtained particles were characterized by TEM to determine their shape and size and Mossbauer Spectroscopy to investigate the chemical state of the iron present. We found that 80% of the particles produced in water are composed of metallic iron and when methanol is used 97% of the particles are metallic iron. Once the Fe colloid was formed, orange skin was impregnated with these nanostructures for the removal of in water solution. The Cr(VI) removal experiments were done in a batch system in the presence of the composites at an inicial concentration of 50 ppm of Cr(VI). When using the iron nanostructures supported on the orange peel, the percentage of removal is 100% in the case of nanostructures formed in water and 96% when obtained in methanol.

  17. Intracellular trafficking of silicon particles and logic-embedded vectors

    Science.gov (United States)

    Ferrati, Silvia; Mack, Aaron; Chiappini, Ciro; Liu, Xuewu; Bean, Andrew J.; Ferrari, Mauro; Serda, Rita E.

    2010-08-01

    Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon particles to be optimized for specific applications such as vascular targeting and avoidance of biological barriers commonly found between the site of drug injection and the final destination. In this study, the intracellular trafficking of unloaded carrier silicon particles and carrier particles loaded with secondary iron oxide nanoparticles was investigated. Following cellular uptake, membrane-encapsulated silicon particles migrated to the perinuclear region of the cell by a microtubule-driven mechanism. Surface charge, shape (spherical and hemispherical) and size (1.6 and 3.2 μm) of the particle did not alter the rate of migration. Maturation of the phagosome was associated with an increase in acidity and acquisition of markers of late endosomes and lysosomes. Cellular uptake of iron oxide nanoparticle-loaded silicon particles resulted in sorting of the particles and trafficking to unique destinations. The silicon carriers remained localized in phagosomes, while the second stage iron oxide nanoparticles were sorted into multi-vesicular bodies that dissociated from the phagosome into novel membrane-bound compartments. Release of iron from the cells may represent exocytosis of iron oxide nanoparticle-loaded vesicles. These results reinforce the concept of multi-functional nanocarriers, in which different particles are able to perform specific tasks, in order to deliver single- or multi-component payloads to specific sub-cellular compartments.Mesoporous silicon particles show great promise for use in drug delivery and imaging applications as carriers for second-stage nanoparticles and higher order particles or therapeutics. Modulation of particle geometry, surface chemistry, and porosity allows silicon

  18. Iron economy in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Glaesener, Anne G; Merchant, Sabeeha S; Blaby-Haas, Crysten E

    2013-09-02

    While research on iron nutrition in plants has largely focused on iron-uptake pathways, photosynthetic microbes such as the unicellular green alga Chlamydomonas reinhardtii provide excellent experimental systems for understanding iron metabolism at the subcellular level. Several paradigms in iron homeostasis have been established in this alga, including photosystem remodeling in the chloroplast and preferential retention of some pathways and key iron-dependent proteins in response to suboptimal iron supply. This review presents our current understanding of iron homeostasis in Chlamydomonas, with specific attention on characterized responses to changes in iron supply, like iron-deficiency. An overview of frequently used methods for the investigation of iron-responsive gene expression, physiology and metabolism is also provided, including preparation of media, the effect of cell size, cell density and strain choice on quantitative measurements and methods for the determination of metal content and assessing the effect of iron supply on photosynthetic performance.

  19. Iron economy in Chlamydomonas reinhardtii

    Directory of Open Access Journals (Sweden)

    Anne G. Glaesener

    2013-09-01

    Full Text Available While research on iron nutrition in plants has largely focused on iron-uptake pathways, photosynthetic microbes such as the unicellular green alga Chlamydomonas reinhardtii provide excellent experimental systems for understanding iron metabolism at the subcellular level. Several paradigms in iron homeostasis have been established in this alga, including photosystem remodeling in the chloroplast and preferential retention of some pathways and key iron-dependent proteins in response to suboptimal iron supply. This review presents our current understanding of iron homeostasis in Chlamydomonas, with specific attention on characterized responses to changes in iron supply, like iron-deficiency. An overview of frequently used methods for the investigation of iron-responsive gene expression, physiology and metabolism is also provided, including preparation of media, the effect of cell size, cell density and strain choice on quantitative measurements and methods for the determination of metal content and assessing the effect of iron supply on photosynthetic performance.

  20. A REVIEW OF THE BIOGENESIS OF IRON NANOPARTICLES USING MICROORGANIMS AND THEIR APPLICATIONS

    OpenAIRE

    Lilia Anghel; Gheorghe Duca

    2013-01-01

    Iron-based nanoparticles have gained a lot of attention due to their properties which offer a broad range of biomedical and industrial applications. Traditional methods of synthesis of iron nanoparticles strongly influence their properties and limit their applicability. Recently, there has been a growing interest in the development of biological routes of syntheses of iron nanoparticles as the resulting particles have structural characteristics required by biomedical field. The mechanism for ...

  1. Iron-Virus Interactions in the Oceans

    Science.gov (United States)

    Bonnain, C. C.; Buck, K. N.; Breitbart, M.

    2016-02-01

    Iron is an essential nutrient in the oceans, with the sub-nanomolar concentrations found in open ocean surface waters often insufficient for supporting biological activity. More than 99.9% of dissolved iron is bound to organic ligands, yet identifying the sources of these ligands in seawater remains a major challenge. A significant portion of iron-binding ligands fall into the colloidal fraction, which is operationally defined as the fraction collected between a 0.02 µm and a 0.45 µm filter. Among the organic ligands in this fraction persists an extremely abundant biological candidate: viruses. On average there are 107 viruses per milliliter of seawater, most of which are phages (viruses that infect bacteria). The impact of viruses on ocean biogeochemistry is often evoked purely through the act of lysing hosts and very few studies have considered the geochemical potential of the viral particles themselves. Recent work in non-marine model systems has revealed the presence of iron atoms within the structure of diverse phages infecting Escherichia coli. Combined with the small size and sheer abundance of phages in the oceans, the inclusion of iron in phage structures would translate into a major factor for cycling of this important trace metal. In addition, iron is so critical for growth that bacteria have evolved multiple uptake systems for assimilating iron, such as siderophores. Certain outer membrane proteins serve a dual function in siderophore uptake and as a phage receptor, suggesting that some of the strategies utilized for iron acquisition make bacteria vulnerable to phage infection. Given the constant arms race between bacteria and phages to develop resistance and counter-resistance, respectively, it is not surprising that phage would have evolved to utilize critical regions of surface-exposed proteins which are indispensable for bacterial growth as receptors. The research presented here explores the potential of marine phages to serve as iron

  2. Iron sufficiency of Canadians.

    Science.gov (United States)

    Cooper, Marcia; Greene-Finestone, Linda; Lowell, Hélène; Levesque, Johanne; Robinson, Stacey

    2012-12-01

    Iron deficiency is the most common nutritional deficiency in the world, but little is known about the iron status of people in Canada, where the last estimates are from 1970-1972. The data are from cycle 2 (2009 to 2011) of the Canadian Health Measures Survey, which collected blood samples from a nationally representative sample of Canadians aged 3 to 79. Descriptive statistics (percentages, arithmetic means, geometric means) were used to estimate hemoglobin and serum ferritin concentrations, and other markers of iron status. Analyses were performed by age/sex group, household income, self-perceived health, diet, and use of iron supplements. World Health Organization reference values (2001) were used to estimate the prevalence of iron sufficiency and anemia. The overall prevalence of anemia was low in the 2009-to-2011 period--97% of Canadians had sufficient hemoglobin levels. Generally, hemoglobin concentration increased compared with 1970-1972; however, at ages 65 to 79, rates of anemia were higher than in 1970-1972. Depleted iron stores were found in 13% of females aged 12 to 19 and 9% of females aged 20 to 49. Lower household income was associated with a lower prevalence of hemoglobin sufficiency, but was not related to lower serum ferritin sufficiency. Self-perceived health and diet were not significantly associated with hemoglobin and serum ferritin levels. The lack of a relationship between iron status and diet may be attributable to the use of questions about food consumption frequency that were not specifically designed to estimate dietary iron intake. Factors other than iron intake might have contributed to the increase in the prevalence of anemia among seniors.

  3. Synthesis of acid-stabilized iron oxide nanoparticles and comparison for targeting atherosclerotic plaques: evaluation by MRI, quantitative MPS, and TEM alternative to ambiguous Prussian blue iron staining.

    Science.gov (United States)

    Scharlach, Constantin; Kratz, Harald; Wiekhorst, Frank; Warmuth, Carsten; Schnorr, Jörg; Genter, Gesche; Ebert, Monika; Mueller, Susanne; Schellenberger, Eyk

    2015-07-01

    To further optimize citrate-stabilized VSOPs (very small iron oxide particles, developed for MR angiography) for identification of atherosclerotic plaques, we modified their surface during synthesis using eight other acids for electrostatic stabilization. This approach preserves effective production for clinical application. Five particles were suitable to be investigated in targeting plaques of apoE(-/-) mice. Accumulation was evaluated by ex vivo MRI, TEM, and quantitatively by magnetic particle spectroscopy (MPS). Citric- (VSOP), etidronic-, tartaric-, and malic-acid-coated particles accumulated in atherosclerotic plaques with highest accumulation for VSOP (0.2‰ of injected dose). Targets were phagolysosomes of macrophages and of altered endothelial cells. In vivo MRI with VSOP allowed for definite plaque identification. Prussian blue staining revealed abundant endogenous iron in plaques, indistinguishable from particle iron. In apoE(-/-) mice, VSOPs are still the best anionic iron oxide particles for imaging atherosclerotic plaques. MPS allows for quantification of superparamagnetic nanoparticles in such small specimens. The presence of vulnerable plaques in arteries is important for the prediction of acute coronary events. VSOP (very small iron oxide particles, developed for MR angiography) have been shown to be very sensitive in identifying atherosclerotic plaques. The authors studied here further modification to the surface of VSOP during synthesis and compared their efficacy. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Hexavalent chromium reduction with scrap iron in continuous-flow system. Part 2: Effect of scrap iron shape and size.

    Science.gov (United States)

    Gheju, M; Balcu, I

    2010-10-15

    Hexavalent chromium reduction with scrap iron has the advantage that two wastes are treated simultaneously. The reduction of hexavalent chromium by scrap iron was investigated in continuous system, using as reducing agent the following scrap iron shapes and sizes: (1) spiral fibers, (2) shavings, and (3) powder. The shape and size of scrap iron were found to have a significant influence on chromium and iron species concentration in column effluent, on column effluent pH and on Cr(VI) reduction mechanism. While for large scrap iron particles (spiral fibers) homogeneous reduction is the dominant Cr(VI) reduction process, for small scrap iron particles (powder) heterogeneous reduction appears to be the dominant reaction contributing to Cr(VI) reduction. All three shapes and sizes investigated in this work have both advantages and disadvantages. If found in sufficient quantities, scrap iron powder seem to be the optimum shape and size for the continuous reduction of Cr(VI), due to the following advantages: (1) the greatest reduction capacity, (2) the most important pH increase in column effluent (up to 6.3), (3) no chromium was detected in the column effluent during the first 60 h of the experiment, and (4) the lowest steady-state Cr(VI) concentration observed in column effluent (3.7 mg/L). But, despite of a lower reduction capacity in comparison with powder particles, spiral fibers and shavings have the advantage to result in large quantities from the mechanic processing of steel. 2010 Elsevier B.V. All rights reserved.

  5. Experimental Research on the Determination of the Coefficient of Sliding Wear under Iron Ore Handling Conditions

    NARCIS (Netherlands)

    Chen, G.; Liu, Y.; Lodewijks, G.; Schott, D.L.

    2017-01-01

    The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is

  6. Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume

    Energy Technology Data Exchange (ETDEWEB)

    Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.; Santelli, Cara M.; Marcus, Matthew A.; Moffett, James W.; Rouxel, Olivier; German, Christopher R.; Edwards, Katrina J.

    2008-09-20

    Hydrothermal venting associated with mid-ocean ridge volcanism is globally widespread. This venting is responsible for a dissolved iron flux to the ocean that is approximately equal to that associated with continental riverine runoff. For hydrothermal fluxes, it has long been assumed that most of the iron entering the oceans is precipitated in inorganic forms. However, the possibility of globally significant fluxes of iron escaping these mass precipitation events and entering open-ocean cycles is now being debated, and two recent studies suggest that dissolved organic ligands might influence the fate of hydrothermally vented metals. Here we present spectromicroscopic measurements of iron and carbon in hydrothermal plume particles at the East Pacific Rise mid-ocean ridge. We show that organic carbon-rich matrices, containing evenly dispersed iron(II)-rich materials, are pervasive in hydrothermal plume particles. The absence of discrete iron(II) particles suggests that the carbon and iron associate through sorption or complexation. We suggest that these carbon matrices stabilize iron(II) released from hydrothermal vents in the region, preventing its oxidation and/or precipitation as insoluble minerals. Our findings have implications for deep-sea biogeochemical cycling of iron, a widely recognized limiting nutrient in the oceans.

  7. Coal desulfurization. [using iron pentacarbonyl

    Science.gov (United States)

    Hsu, G. C. (Inventor)

    1979-01-01

    Organic sulfur is removed from coal by treatment with an organic solution of iron pentacarbonyl. Organic sulfur compounds can be removed by reaction of the iron pentacarbonyl with coal to generate CO and COS off-gases. The CO gas separated from COS can be passed over hot iron fillings to generate iron pentacarbonyl.

  8. Reactive iron in marine sediments

    Science.gov (United States)

    Canfield, Donald E.

    1989-01-01

    The influence of reactive iron oxides on sediment pore-water chemistry is considered in detail. A carefully calibrated extraction scheme is used to determine the depth distributions of reactive iron phases at two very different localities: the relatively iron-rich Mississippi Delta and the relatively iron-poor FOAM site in Long Island Sound. Closed system incubations are used to characterize the rates of reaction between sulfide and both naturally occurring and pure iron mineral phases. Rates of iron liberation to pore solution are measured in the presence and absence of sulfate reduction, and the origin of dissolved iron in organic-rich sediments is speculated upon.

  9. Elementary particles

    Science.gov (United States)

    Fritzsch, Harald; Heusch, Karin

    Introduction -- Electrons and atomic nuclei -- Quantum properties of atoms and particles -- The knives of Democritus -- Quarks inside atomic nuclei -- Quantum electrodynamics -- Quantum chromodynamics -- Mesons, baryons, and quarks -- Electroweak interactions -- Grand unification -- Conclusion.

  10. Ultradispersed Hydrocarbon Synthesis Catalyst from CO and H[2] Based on Electroexplosion of Iron Powder

    OpenAIRE

    Popok, E.V.; Levashova, A.I.; Chekantsev, N.V.; Kirgina, M.V.; Rafegerst, K. V.

    2014-01-01

    The structure and properties of disperse particles of electroexplosive iron-based powder are studied with a laser diffraction method, transmission electron microscopy analysis and X-ray photography. The catalytic activity of ultradispersed iron powders in the synthesis of hydrocarbons from CO and H[2] by Fischer - Tropsch method is measured by concentration of the paramagnetic particles with electron paramagnetic resonance. In the laboratory of catalytic plant, hydrocarbons are synthesized at...

  11. Cohesive strength of iron ore granules

    Science.gov (United States)

    Contreras, Rafael Jaimes; Berger, Nicolas; Izard, Edouard; Douce, Jean-François; Koltsov, Alexey; Delenne, Jean-Yves; Azema, Emilien; Nezamabadi, Saeid; van Loo, Frédéric; Pellenq, Roland; Radjai, Farhang

    2017-06-01

    We present an experimental and numerical investigation of the mechanical strength of crude iron ore (Hematite) granules in which capillary bonds between primary particles are the source of internal cohesion. The strength is measured by subjecting the granules to vertical compression between two plates. We show that the behavior of the granules is ductile with a well-defined plastic threshold which increases with the amount of water. It is found that the compressive strength scales with capillary cohesion with a pre-factor that is nearly independent of size polydispersity for the investigated range of parameters but increases with friction coefficient between primary particles. This weak dependence may be attributed to the class of fine particles which, due to their large number, behaves as a cohesive matrix that controls the strength of the granule.

  12. Auroral particles

    Science.gov (United States)

    Evans, David S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  13. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... have heavy menstrual flow, your doctor may prescribe birth control pills to help reduce your monthly blood flow. ... term but can't take iron supplements by mouth. This therapy also is given to people who ...

  14. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... bleeding. Other At-Risk Groups People who get kidney dialysis treatment may develop iron-deficiency anemia. This ... because blood is lost during dialysis. Also, the kidneys are no longer able to make enough of ...

  15. Iron-Deficiency Anemia

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    Full Text Available ... the tongue, cracks in the sides of the mouth, an enlarged spleen, and frequent infections. People who ... term but can't take iron supplements by mouth. This therapy also is given to people who ...

  16. Iron-Deficiency Anemia

    Medline Plus

    Full Text Available ... low iron levels within months. Supplements come in pill form or in drops for children. Large amounts ... menstrual flow, your doctor may prescribe birth control pills to help reduce your monthly blood flow. In ...

  17. Iron-Deficiency Anemia

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    Full Text Available ... if you have intestinal surgery (such as gastric bypass) or a disease of the intestine (such as ... produce red blood cells. People who have gastric bypass surgery also may develop iron-deficiency anemia. This ...

  18. Iron-Deficiency Anemia

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    Full Text Available ... Safety Sleep Science and Sleep Disorders Lung Diseases Heart and Vascular Diseases Precision Medicine Activities Obesity, Nutrition, ... symptoms. Severe iron-deficiency anemia can lead to heart problems, infections, problems with growth and development in ...

  19. Iron-Deficiency Anemia

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    Full Text Available ... with iron absorption. Risk Factors Infants and Young Children Infants and young children need a lot of ... the condition in these groups. Infants and Young Children A baby's diet can affect his or her ...

  20. Iron-Deficiency Anemia

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    Full Text Available ... NHLBI About NHLBI Home Mission and Strategic Vision Leadership Scientific Divisions Operations and Administration Advisory Committees Budget ... include poor appetite, slowed growth and development, and behavioral problems. Signs and Symptoms of Iron Deficiency Signs ...