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Open AccessArticle High-Temperature Wide Thermal Hysteresis of an Iron(II) Dinuclear Double Helicate

Inorganics 2017, 5(3), 49; doi:10.3390/inorganics5030049

Received: 28 June 2017 / Revised: 25 July 2017 / Accepted: 25 July 2017 / Published: 28 July 2017

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Abstract

Two new dinuclear iron(II) complexes (1·PF₆ and 1·AsF₆) of the general formula [Fe^II₂(L2^C3)₂](X)₄·nH₂O·mMeCN (X = PF₆, n = m = 1.5 for 1·PF₆ and X

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Two new dinuclear iron(II) complexes (1·PF₆ and 1·AsF₆) of the general formula [Fe^II₂(L2^C3)₂](X)₄·nH₂O·mMeCN (X = PF₆, n = m = 1.5 for 1·PF₆ and X = AsF₆, n = 3, m = 1 for 1·AsF₆) have been prepared and structurally characterized, where L2^C3 is a bis-1,2,3-triazolimine type Schiff-base ligand, 1,1′-[propane-1,3-diylbis(1H-1,2,3-triazole-1,4-diyl)]bis{N-[2-(pyridin-2-yl)ethyl]methanimine}. Single crystal X-ray structure analyses revealed that 1·PF₆ and 1·AsF₆ are isostructural. The complex-cation [Fe^II₂(L2^C3)₂]⁴⁺ of both has the same dinuclear double helicate architecture, in which each iron(II) center has an N6 octahedral coordination environment. Neighboring helicates are connected by intermolecular π–π interactions to give a chiral one-dimensional (1D) structure, and cationic 1D chains with the opposite chirality exist in the crystal lattice to give a heterochiral crystal. Magnetic and differential scanning calorimetry (DSC) studies were performed only for 1·AsF₆, since the thermal stability in a high-temperature spin crossover (SCO) region of 1·PF₆ is poorer than that of 1·AsF₆. 1·AsF₆ shows an unsymmetrical hysteretic SCO between the low-spin–low-spin (LS–LS) and high-spin–high-spin (HS–HS) states at above room temperature. The critical temperatures of warming (T_c↑) and cooling (T_c↓) modes in the abrupt spin transition area are 485 and 401 K, respectively, indicating the occurrence of 84 K-wide thermal hysteresis in the first thermal cycle. Full article

(This article belongs to the Special Issue Spin-Crossover Complexes)

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Open AccessArticle Iron Bioavailability Studies of the First Generation of Iron-Biofortified Beans Released in Rwanda

by Raymond Glahn, Elad Tako, Jonathan Hart, Jere Haas, Mercy Lung’aho and Steve Beebe

Nutrients 2017, 9(7), 787; doi:10.3390/nu9070787

Received: 22 June 2017 / Revised: 12 July 2017 / Accepted: 17 July 2017 / Published: 21 July 2017

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Abstract

This paper represents a series of in vitro iron (Fe) bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans (Phaseolus vulgaris) selected for human trials in Rwanda and released to farmers of that region.

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This paper represents a series of in vitro iron (Fe) bioavailability experiments, Fe content analysis and polyphenolic profile of the first generation of Fe biofortified beans (Phaseolus vulgaris) selected for human trials in Rwanda and released to farmers of that region. The objective of the present study was to demonstrate how the Caco-2 cell bioassay for Fe bioavailability can be utilized to assess the nutritional quality of Fe in such varieties and how they may interact with diets and meal plans of experimental studies. Furthermore, experiments were also conducted to directly compare this in vitro approach with specific human absorption studies of these Fe biofortified beans. The results show that other foods consumed with beans, such as rice, can negatively affect Fe bioavailability whereas potato may enhance the Fe absorption when consumed with beans. The results also suggest that the extrinsic labelling approach to measuring human Fe absorption can be flawed and thus provide misleading information. Overall, the results provide evidence that the Caco-2 cell bioassay represents an effective approach to evaluate the nutritional quality of Fe-biofortified beans, both separate from and within a targeted diet or meal plan. Full article

(This article belongs to the Special Issue Fe Deficiency, Dietary Bioavailbility and Absorption)

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Open AccessArticle Transition of the Interface between Iron and Carbide Precipitate From Coherent to Semi-Coherent

by Hideaki Sawada, Shunsuke Taniguchi, Kazuto Kawakami and Taisuke Ozaki

Metals 2017, 7(7), 277; doi:10.3390/met7070277

Received: 5 May 2017 / Revised: 10 July 2017 / Accepted: 14 July 2017 / Published: 19 July 2017

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Abstract

There are some precipitates that undergo transition from a coherent to semi-coherent state during growth. An example of such a precipitate in steel is carbide with a NaCl-type structure, such as TiC and NbC. The interface energy between carbide precipitate and iron is

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There are some precipitates that undergo transition from a coherent to semi-coherent state during growth. An example of such a precipitate in steel is carbide with a NaCl-type structure, such as TiC and NbC. The interface energy between carbide precipitate and iron is obtained via large-scale first-principles electronic structure calculation. The strain energy is estimated by structure optimization of the iron matrix with virtual carbide precipitate using the empirical potential. The transition of the interface from a coherent to semi-coherent state was examined by comparing the interface and strain energies between the coherent and semi-coherent interfaces. The sizes where both the precipitates undergo this transition are smaller than those of the interfaces with minimum misfit. The estimated transition diameter of TiC is in agreement with the experimentally obtained value. Full article

(This article belongs to the Special Issue First-Principles Approaches to Metals, Alloys, and Metallic Compounds)

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Open AccessArticle Characteristics of Cold and Hot Pressed Iron Aluminum Powder Metallurgical Alloys

by Ahmed Nassef, Waleed H. El-Garaihy and Medhat El-Hadek

Metals 2017, 7(5), 170; doi:10.3390/met7050170

Received: 4 March 2017 / Revised: 29 April 2017 / Accepted: 3 May 2017 / Published: 12 May 2017

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Abstract

Iron powders having average particle sizes of ~40 µm are mechanically mixed thoroughly with aluminum powders ranging from 1 to 10 in wt. %, with an average particle size of ~10 µm. Two different powder metallurgy (PM) techniques, cold and hot pressing, are

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Iron powders having average particle sizes of ~40 µm are mechanically mixed thoroughly with aluminum powders ranging from 1 to 10 in wt. %, with an average particle size of ~10 µm. Two different powder metallurgy (PM) techniques, cold and hot pressing, are used to study the effect of the additive element powder on the mechanical properties, wear properties, and the microstructure of the iron based alloys. The hot pressing technique was performed at a temperature reaching up to 500 °C at 445.6 MPa. The cold pressing technique was performed at 909 MPa at room temperature. By increasing the Al content to 10 wt. % in the base Fe-based matrix, the Brinell hardness number was decreased from 780 to 690 and the radial strength from 380 to 228 MPa with reductions of 11.5% and 40%, respectively. Improvement of the wear resistance with the increase addition of the Al powder to the Fe matrix up to five times was achieved, compared to the alloy without Al addition for different wear parameters: wear time and sliding speed. Full article

(This article belongs to the Special Issue Metal Matrix Composites)

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Open AccessArticle Discrete Element Method Simulations of the Inter-Particle Contact Parameters for the Mono-Sized Iron Ore Particles

by Tongqing Li, Yuxing Peng, Zhencai Zhu, Shengyong Zou and Zixin Yin

Materials 2017, 10(5), 520; doi:10.3390/ma10050520

Received: 22 March 2017 / Revised: 24 April 2017 / Accepted: 10 May 2017 / Published: 11 May 2017

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Abstract

Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling

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Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact parameters between the particle and wall were arbitrarily assumed, in order to purely assess its impact on the angle of repose for the mono-sized iron ore particles. Results show that varying the restitution coefficient over the range considered does not lead to any obvious difference in the angle of repose, but the angle of repose has strong sensitivity to the rolling/static friction coefficient. The impacts of the rolling/static friction coefficient on the angle of repose are interrelated, and increasing the inter-particle rolling/static friction coefficient can evidently increase the angle of repose. However, the impact of the static friction coefficient is more profound than that of the rolling friction coefficient. Finally, a predictive equation is established and a very close agreement between the predicted and simulated angle of repose is attained. This predictive equation can enormously shorten the inter-particle contact parameters calibration time that can help in the implementation of DEM simulations. Full article

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Open AccessReview Light to Hydrogen: Photocatalytic Hydrogen Generation from Water with Molecularly-Defined Iron Complexes

by Henrik Junge, Nils Rockstroh, Steffen Fischer, Angelika Brückner, Ralf Ludwig, Stefan Lochbrunner, Oliver Kühn and Matthias Beller

Inorganics 2017, 5(1), 14; doi:10.3390/inorganics5010014

Received: 27 January 2017 / Revised: 27 February 2017 / Accepted: 27 February 2017 / Published: 9 March 2017

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Abstract

Photocatalytic hydrogen generation is considered to be attractive due to its combination of solar energy conversion and storage. Currently-used systems are either based on homogeneous or on heterogeneous materials, which possess a light harvesting and a catalytic subunit. The subject of this review

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Photocatalytic hydrogen generation is considered to be attractive due to its combination of solar energy conversion and storage. Currently-used systems are either based on homogeneous or on heterogeneous materials, which possess a light harvesting and a catalytic subunit. The subject of this review is a brief summary of homogeneous proton reduction systems using sacrificial agents with special emphasis on non-noble metal systems applying convenient iron(0) sources. Iridium photosensitizers, which were proven to have high quantum yields of up to 48% (415 nm), have been employed, as well as copper photosensitizers. In both cases, the addition or presence of a phosphine led to the transformation of the iron precursor with subsequently increased activities. Reaction pathways were investigated by photoluminescence, electron paramagnetic resonance (EPR), Raman, FTIR and mass spectroscopy, as well as time-dependent DFT-calculations. In the future, this knowledge will set the basis to design photo(electro)chemical devices with tailored electron transfer cascades and without the need for sacrificial agents. Full article

(This article belongs to the Special Issue Photochemical Water Splitting)

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Open AccessArticle Assessing the Validity and Reproducibility of an Iron Dietary Intake Questionnaire Conducted in a Group of Young Polish Women

by Dominika Głąbska, Dominika Guzek, Joanna Ślązak and Dariusz Włodarek

Nutrients 2017, 9(3), 199; doi:10.3390/nu9030199

Received: 22 December 2016 / Revised: 4 February 2017 / Accepted: 10 February 2017 / Published: 27 February 2017

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Abstract

The aim of the study was to analyse a designed brief iron dietary intake questionnaire based on a food frequency assessment (IRONIC-FFQ—IRON Intake Calculation-Food Frequency Questionnaire), including the assessment of validity and reproducibility in a group of 75 Polish women aged 20–30 years.

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The aim of the study was to analyse a designed brief iron dietary intake questionnaire based on a food frequency assessment (IRONIC-FFQ—IRON Intake Calculation-Food Frequency Questionnaire), including the assessment of validity and reproducibility in a group of 75 Polish women aged 20–30 years. Participants conducted 3-day dietary records and filled in the IRONIC-FFQ twice (FFQ1—directly after the dietary record and FFQ2—6 weeks later). The analysis included an assessment of validity (comparison with the results of the 3-day dietary record) and of reproducibility (comparison of the results obtained twice—FFQ1 and FFQ2). In the analysis of validity, the share of individuals correctly classified into tertiles was over 50% (weighted κ of 0.36), while analysis of correlation revealed correlation coefficients of almost 0.5. In the assessment of reproducibility, almost 80% of individuals were correctly classified and less than 3% were misclassified (weighted κ of 0.73), while a correlation coefficient higher than 0.85 was obtained. Both in the assessment of validity and of reproducibility, a Bland–Altman index of 6.7% was recorded (93.3% of compared pairs of results were in the acceptable range, attributed to differences within ± 2SD limit). Validation of the IRONIC-FFQ revealed a satisfactory level of validity and positively validated reproducibility. Full article

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Open AccessArticle Synthesis, Characterization, and Toxicity Evaluation of Dextran-Coated Iron Oxide Nanoparticles

by Mihaela Balas, Carmen Steluta Ciobanu, Carmen Burtea, Miruna Silvia Stan, Eugenia Bezirtzoglou, Daniela Predoi and Anca Dinischiotu

Metals 2017, 7(2), 63; doi:10.3390/met7020063

Received: 19 November 2016 / Revised: 6 February 2017 / Accepted: 15 February 2017 / Published: 21 February 2017

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Abstract

We report the synthesis of dextran-coated iron oxide magnetic nanoparticles (DIO-NPs) with spherical shape and uniform size distribution as well as their accumulation and toxic effects on Jurkat cells up to 72 h. The characterization of dextran-coated maghemite nanoparticles was done by X-ray

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We report the synthesis of dextran-coated iron oxide magnetic nanoparticles (DIO-NPs) with spherical shape and uniform size distribution as well as their accumulation and toxic effects on Jurkat cells up to 72 h. The characterization of dextran-coated maghemite nanoparticles was done by X-ray diffraction and dynamic light scattering analyses, transmission electron microscopy imaging, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, magnetic hysteresis, and relaxometry measurements. The quantification of DIO-NPs intracellular uptake showed a progressive accumulation of iron as a function of time and dose accompanied by additional lysosome formation and an increasing darkening exhibited by a magnetic resonance imaging (MRI) scanner. The cytotoxicity assays revealed a decrease of cell viability and a loss of membrane integrity in a time- and dose-dependent manner. Exposure to DIO-NPs determined an increase in reactive oxygen species level up to 72 h. In the first two days of exposure, the level of reduced glutathione decreased and the amount of malondyaldehyde increased, but at the end of the experiment, their concentrations returned to control values. These nanoparticles could be used as contrast agents for MRI but several parameters concerning their interaction with the cells should be taken into consideration for a safe utilization. Full article

(This article belongs to the Special Issue Metallic and Metal Oxide Nanoparticles: Novel Approaches)

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Open AccessArticle Efficiency of Iron-Based Oxy-Hydroxides in Removing Antimony from Groundwater to Levels below the Drinking Water Regulation Limits

by Konstantinos Simeonidis, Vasiliki Papadopoulou, Sofia Tresintsi, Evgenios Kokkinos, Ioannis A. Katsoyiannis, Anastasios I. Zouboulis and Manassis Mitrakas

Sustainability 2017, 9(2), 238; doi:10.3390/su9020238

Received: 22 November 2016 / Revised: 16 January 2017 / Accepted: 5 February 2017 / Published: 10 February 2017

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Abstract

This study evaluates the efficiency of iron-based oxy-hydroxides to remove antimony from groundwater to meet the requirements of drinking water regulations. Results obtained by batch adsorption experiments indicated that the qualified iron oxy-hydroxide (FeOOH), synthesized at pH 4 for maintaining a high positive

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This study evaluates the efficiency of iron-based oxy-hydroxides to remove antimony from groundwater to meet the requirements of drinking water regulations. Results obtained by batch adsorption experiments indicated that the qualified iron oxy-hydroxide (FeOOH), synthesized at pH 4 for maintaining a high positive charge density (2.5 mmol OH⁻/g) achieved a residual concentration of Sb(III) below the EU drinking water regulation limit of 5 μg/L by providing an adsorption capacity of 3.1 mg/g. This is more than twice greater compared either to similar commercial FeOOHs (GFH, Bayoxide) or to tetravalent manganese feroxyhyte (Fe-MnOOH) adsorbents. In contrast, all tested adsorbents failed to achieve a residual concentration below 5 μg/L for Sb(V). The higher efficiency of the qualified FeOOH was confirmed by rapid small-scale column tests, since an adsorption capacity of 3 mg Sb(III)/g was determined at a breakthrough concentration of 5 μg/L. However, it completely failed to achieve Sb(V) concentrations below 5 μg/L even at the beginning of the column experiments. The results of leaching tests classified the spent qualified FeOOH to inert wastes. Considering the rapid kinetics of this process (i.e., 85% of total removal was performed within 10 min), the developed qualified adsorbent may be promoted as a prospective material for point-of-use Sb(III) removal from water in vulnerable communities, since the adsorbent’s cost was estimated to be close to 30 ± 3.4 €/10³ m³ for every 10 μg Sb(III)/L removed. Full article

(This article belongs to the Special Issue Recent Advances for Water and Wastewater Treatment and Reuse with Emphasis in Applications in Vulnerable Communities)

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Open AccessComment Comment on Neiser et al. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA). Int. J. Mol. Sci. 2016, 17, 1185.

by Claes C. Strom and Hans B. Andreasen

Int. J. Mol. Sci. 2017, 18(1), 121; doi:10.3390/ijms18010121

Received: 28 September 2016 / Revised: 25 November 2016 / Accepted: 6 January 2017 / Published: 10 January 2017

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Abstract

All IV iron complexes carry a risk of potentially fatal allergic type hypersensitivity reactions. The mechanism(s) behind these reactions is unknown but the limited data available suggests that classic IgE mediated allergy is exceedingly rare, if ever occurring. Iron–carbohydrate molecules are complex nano-particles

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All IV iron complexes carry a risk of potentially fatal allergic type hypersensitivity reactions. The mechanism(s) behind these reactions is unknown but the limited data available suggests that classic IgE mediated allergy is exceedingly rare, if ever occurring. Iron–carbohydrate molecules are complex nano-particles and trying to reduce the risk of serious hypersensitivity to antibody binding of an artificial antibody seems meaningless. A recently published analysis of safety data from randomized clinical trials confirms the method reported by Neiser to be useless to predict reaction risk. In conclusion, the study by Neiser et al. is biased, contains no new information, and has no clinical relevance. We are concerned that the association of the authors with a commercial entity has caused a conflict of interest that biases not only the results, but the entire experimental setup against competitors. (Comment on Neiser et al. Int. J. Mol. Sci. 2016, 17, 1185, doi:10.3390/ijms17071185). Full article

Open AccessReview Hydroxypyridinone Chelators: From Iron Scavenging to Radiopharmaceuticals for PET Imaging with Gallium-68

by Ruslan Cusnir, Cinzia Imberti, Robert C. Hider, Philip J. Blower and Michelle T. Ma

Int. J. Mol. Sci. 2017, 18(1), 116; doi:10.3390/ijms18010116

Received: 2 November 2016 / Revised: 5 December 2016 / Accepted: 21 December 2016 / Published: 8 January 2017

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Abstract

Derivatives of 3,4-hydroxypyridinones have been extensively studied for in vivo Fe³⁺ sequestration. Deferiprone, a 1,2-dimethyl-3,4-hydroxypyridinone, is now routinely used for clinical treatment of iron overload disease. Hexadentate tris(3,4-hydroxypyridinone) ligands (THP) complex Fe³⁺ at very low iron concentrations, and their high affinities

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Derivatives of 3,4-hydroxypyridinones have been extensively studied for in vivo Fe³⁺ sequestration. Deferiprone, a 1,2-dimethyl-3,4-hydroxypyridinone, is now routinely used for clinical treatment of iron overload disease. Hexadentate tris(3,4-hydroxypyridinone) ligands (THP) complex Fe³⁺ at very low iron concentrations, and their high affinities for oxophilic trivalent metal ions have led to their development for new applications as bifunctional chelators for the positron emitting radiometal, ⁶⁸Ga³⁺, which is clinically used for molecular imaging in positron emission tomography (PET). THP-peptide bioconjugates rapidly and quantitatively complex ⁶⁸Ga³⁺ at ambient temperature, neutral pH and micromolar concentrations of ligand, making them amenable to kit-based radiosynthesis of ⁶⁸Ga PET radiopharmaceuticals. ⁶⁸Ga-labelled THP-peptides accumulate at target tissue in vivo, and are excreted largely via a renal pathway, providing high quality PET images. Full article

(This article belongs to the Special Issue Cancer Molecular Imaging in the Era of Precision Medicine)

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Open AccessArticle Size Control of Carbon Encapsulated Iron Nanoparticles by Arc Discharge Plasma Method

by Mohammad Reza Sanaee, Stefanos Chaitoglou, Noemí Aguiló-Aguayo and Enric Bertran

Appl. Sci. 2017, 7(1), 26; doi:10.3390/app7010026

Received: 15 November 2016 / Revised: 16 December 2016 / Accepted: 20 December 2016 / Published: 26 December 2016

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Abstract

Size control of core@shell nanostructures is still a challenge. Carbon encapsulated iron nanoparticles (CEINPs) were synthesized by arc discharge plasma method in this study. CEINPs size can be controlled by varying gas composition, due to change in plasma properties. The morphology and structural

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Size control of core@shell nanostructures is still a challenge. Carbon encapsulated iron nanoparticles (CEINPs) were synthesized by arc discharge plasma method in this study. CEINPs size can be controlled by varying gas composition, due to change in plasma properties. The morphology and structural features were investigated using scanning electron microscopy, transmission electron microscopy (TEM) and high-resolution TEM. Magnetic properties were studied to confirm the changes in CEINPs size by using superconducting quantum interference device. In order to evaluate the carbon shell protection and ensure the absence of iron oxide, selected area electron diffraction technique, energy-dispersive x-ray spectroscopy and electron energy loss spectroscopy were employed. Moreover, the degree of carbon order–disorder was studied by Raman Spectroscopy. It was concluded that arc discharge method is a suitable technique for precise size control of CEINPs. Full article

(This article belongs to the Special Issue Biodegradable and Biocompatible Nanoparticles)

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

by Toshitaka Ishizaki, Hideyuki Nakano, Shin Tajima and Naoko Takahashi

Nanomaterials 2017, 7(1), 1; doi:10.3390/nano7010001

Received: 19 October 2016 / Revised: 14 December 2016 / Accepted: 15 December 2016 / Published: 23 December 2016

Abstract

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

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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. Full article

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Open AccessFeature PaperReview Exchange Bias Effects in Iron Oxide-Based Nanoparticle Systems

by Manh-Huong Phan, Javier Alonso, Hafsa Khurshid, Paula Lampen-Kelley, Sayan Chandra, Kristen Stojak Repa, Zohreh Nemati, Raja Das, Óscar Iglesias and Hariharan Srikanth

Nanomaterials 2016, 6(11), 221; doi:10.3390/nano6110221

Received: 24 August 2016 / Revised: 29 October 2016 / Accepted: 2 November 2016 / Published: 23 November 2016

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Abstract

The exploration of exchange bias (EB) on the nanoscale provides a novel approach to improving the anisotropic properties of magnetic nanoparticles for prospective applications in nanospintronics and nanomedicine. However, the physical origin of EB is not fully understood. Recent advances in chemical synthesis

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The exploration of exchange bias (EB) on the nanoscale provides a novel approach to improving the anisotropic properties of magnetic nanoparticles for prospective applications in nanospintronics and nanomedicine. However, the physical origin of EB is not fully understood. Recent advances in chemical synthesis provide a unique opportunity to explore EB in a variety of iron oxide-based nanostructures ranging from core/shell to hollow and hybrid composite nanoparticles. Experimental and atomistic Monte Carlo studies have shed light on the roles of interface and surface spins in these nanosystems. This review paper aims to provide a thorough understanding of the EB and related phenomena in iron oxide-based nanoparticle systems, knowledge of which is essential to tune the anisotropic magnetic properties of exchange-coupled nanoparticle systems for potential applications. Full article

(This article belongs to the Special Issue Functional Magnetic Nanoparticles in Nanomedicine)

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Open AccessArticle An Analysis of the Weldability of Ductile Cast Iron Using Inconel 625 for the Root Weld and Electrodes Coated in 97.6% Nickel for the Filler Welds

by Francisco-Javier Cárcel-Carrasco, Miguel-Angel Pérez-Puig, Manuel Pascual-Guillamón and Rafael Pascual-Martínez

Metals 2016, 6(11), 283; doi:10.3390/met6110283

Received: 26 July 2016 / Revised: 5 November 2016 / Accepted: 14 November 2016 / Published: 18 November 2016

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Abstract

This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG) welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The

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This article examines the weldability of ductile cast iron when the root weld is applied with a tungsten inert gas (TIG) welding process employing an Inconel 625 source rod, and when the filler welds are applied with electrodes coated with 97.6% Ni. The welds were performed on ductile cast iron specimen test plates sized 300 mm × 90 mm × 10 mm with edges tapered at angles of 60°. The plates were subjected to two heat treatments. This article analyzes the influence on weldability of the various types of electrodes and the effect of preheat treatments. Finally, a microstructure analysis is made of the material next to the weld in the metal-weld interface and in the weld itself. The microstructure produced is correlated with the strength of the welds. We treat an alloy with 97.6% Ni, which prevents the formation of carbides. With a heat treatment at 900 °C and 97.6% Ni, there is a dissolution of all carbides, forming nodules in ferritic matrix graphite. Full article

(This article belongs to the Special Issue Advances in Welding Metal Alloys, Dissimilar Metals and Additively Manufactured Parts)

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Open AccessArticle Preparation of Magnetic Iron Oxide Nanoparticles (MIONs) with Improved Saturation Magnetization Using Multifunctional Polymer Ligand

by Muhammad Irfan Majeed, Jiaojiao Guo, Wei Yan and Bien Tan

Polymers 2016, 8(11), 392; doi:10.3390/polym8110392

Received: 4 October 2016 / Revised: 30 October 2016 / Accepted: 31 October 2016 / Published: 8 November 2016

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Abstract

This paper describes the preparation of ultra-small magnetic iron oxide (Fe₃O₄) nanoparticles (MIONs) coated with water-soluble thioether end-functionalized polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-polymethacrylic acid (PTMP-PMAA). The MIONs were prepared by co-precipitation of aqueous iron precursor solution at a high

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This paper describes the preparation of ultra-small magnetic iron oxide (Fe₃O₄) nanoparticles (MIONs) coated with water-soluble thioether end-functionalized polymer ligand pentaerythritol tetrakis 3-mercaptopropionate-polymethacrylic acid (PTMP-PMAA). The MIONs were prepared by co-precipitation of aqueous iron precursor solution at a high temperature. The polymer modified MIONs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometery (VSM). It was found that these MIONs were successfully modified by this water-soluble polymer ligand with a fairly uniform size and narrow size distribution. The dried powder of MIONs could be stored for a long time and re-dispersed well in water without any significant change. Additionally, the polymer concentration showed a significant effect on size and magnetic properties of the MIONs. The saturation magnetization was increased by optimizing the polymer concentration. Furthermore, the 3-(4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide (MTT)-assay demonstrated that these MIONs were highly biocompatible and they could be successfully coupled with fluorescent dye Rhodamine due to the formation of amide bond between carboxylic acid groups of MIONs and amine groups of dye. The obtained results indicated that these multifunctional MIONs with rich surface chemistry exhibit admirable potential in biomedical applications. Full article

(This article belongs to the Special Issue Hybrid Polymeric Materials)

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Open AccessArticle TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

by Yanhui Liu, Weicheng Qu and Yu Su

Materials 2016, 9(10), 815; doi:10.3390/ma9100815

Received: 25 August 2016 / Revised: 26 September 2016 / Accepted: 26 September 2016 / Published: 30 September 2016

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Abstract

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS)

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In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α-Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage. Full article

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Open AccessArticle Removal of Cr(VI) from Water Using a New Reactive Material: Magnesium Oxide Supported Nanoscale Zero-Valent Iron

by Alessio Siciliano

Materials 2016, 9(8), 666; doi:10.3390/ma9080666

Received: 18 May 2016 / Revised: 1 August 2016 / Accepted: 2 August 2016 / Published: 6 August 2016

Cited by 1 | Viewed by 726 | PDF Full-text (5426 KB) | HTML Full-text | XML Full-text

Abstract

The chromium pollution of water is an important environmental and health issue. Cr(VI) removal by means of metallic iron is an attractive method. Specifically, nanoscopic zero valent iron (NZVI) shows great reactivity, however, its applicability needs to be further investigated. In the present

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The chromium pollution of water is an important environmental and health issue. Cr(VI) removal by means of metallic iron is an attractive method. Specifically, nanoscopic zero valent iron (NZVI) shows great reactivity, however, its applicability needs to be further investigated. In the present paper, NZVI was supported on MgO grains to facilitate the treatments for remediation of chromium-contaminated waters. The performances and mechanisms of the developed composite, in the removal of hexavalent chromium, were investigated by means of batch and continuous tests. Kinetic studies, under different operating conditions, showed that reduction of Cr(VI) could be expressed by a pseudo second-order reaction kinetic. The reaction rate increased with the square of Fe(0) amount, while it was inversely proportional to the initial chromium concentration. The process performance was satisfactory also under uncontrolled pH, and a limited influence of temperature was observed. The reactive material was efficiently reusable for many cycles without any regeneration treatment. The performances in continuous tests were close to 97% for about 80 pore volume of reactive material. Full article

(This article belongs to the Special Issue Green Nanotechnology)

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Open AccessArticle Characterization of Aluminum-Based-Surface Matrix Composites with Iron and Iron Oxide Fabricated by Friction Stir Processing

by Essam R. I. Mahmoud and Mahmoud M. Tash

Materials 2016, 9(7), 505; doi:10.3390/ma9070505

Received: 24 April 2016 / Revised: 11 June 2016 / Accepted: 20 June 2016 / Published: 23 June 2016

Cited by 2 | Viewed by 642 | PDF Full-text (10246 KB) | HTML Full-text | XML Full-text

Abstract

Surface composite layers were successfully fabricated on an A 1050-H24 aluminum plate by dispersed iron (Fe) and magnetite (Fe₃O₄) particles through friction stir processing (FSP). Fe and Fe₃O₄ powders were packed into a groove of 3

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Surface composite layers were successfully fabricated on an A 1050-H24 aluminum plate by dispersed iron (Fe) and magnetite (Fe₃O₄) particles through friction stir processing (FSP). Fe and Fe₃O₄ powders were packed into a groove of 3 mm in width and 1.5 mm in depth, cut on the aluminum plate, and covered with an aluminum sheet that was 2-mm thick. A friction stir processing (FSP) tool of square probe shape, rotated at a rate of 1000–2000 rpm, was plunged into the plate through the cover sheet and the groove, and moved along the groove at a travelling speed of 1.66 mm/s. Double and triple passes were applied. As a result, it is found that the Fe particles were homogenously distributed in the whole nugget zone at a rotation speed of 1000 rpm after triple FSP passes. Limited interfacial reactions occurred between the Fe particles and the aluminum matrix. On the other hand, the lower rotation speed (1000 rpm) was not enough to form a sound nugget when the dispersed particles were changed to the larger Fe₃O₄. The Fe₃O₄ particles were dispersed homogenously in a sound nugget zone when the rotation speed was increased to 1500 rpm. No reaction products could be detected between the Fe₃O₄ particles and the aluminum matrix. The saturation magnetization (Ms) of the Fe-dispersed nugget zone was higher than that of the Fe₃O₄-dispersed nugget zone. Moreover, there were good agreement between the obtained saturation magnetization values relative to that of pure Fe and Fe₃O₄ materials and the volume content of the dispersed particles in the nugget zone. Full article

(This article belongs to the Special Issue Materials' 2016 (Montreal, Canada: June 20 - 24, 2016) - Advances and Trends in Engineering Materials and their Applications)

Open AccessArticle Influence of Ionic Liquids on an Iron(III) Catalyzed Three-Component Coupling/Hydroarylation/Dehydrogenation Tandem Reaction

by Maren Muntzeck and René Wilhelm

Int. J. Mol. Sci. 2016, 17(6), 860; doi:10.3390/ijms17060860

Received: 30 March 2016 / Revised: 1 May 2016 / Accepted: 13 May 2016 / Published: 1 June 2016

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Abstract

A three-component oxidative dehydrogenation tandem reaction via the coupling and hydroarylation of benzaldehyde, aniline and phenylacetylene to a quinoline derivate was catalyzed by an iron-containing ionic liquid. The reaction was air mediated and could be performed under neat conditions. The iron(III) of the

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A three-component oxidative dehydrogenation tandem reaction via the coupling and hydroarylation of benzaldehyde, aniline and phenylacetylene to a quinoline derivate was catalyzed by an iron-containing ionic liquid. The reaction was air mediated and could be performed under neat conditions. The iron(III) of the ionic liquid was the oxidizing species. Full article

(This article belongs to the Special Issue Ionic Liquids 2016 and Selected Papers from ILMAT III)

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Open AccessArticle Fungal Iron Biomineralization in Río Tinto

by Monike Oggerin, Fernando Tornos, Nuria Rodriguez, Laura Pascual and Ricardo Amils

Minerals 2016, 6(2), 37; doi:10.3390/min6020037

Received: 1 January 2016 / Revised: 30 March 2016 / Accepted: 12 April 2016 / Published: 18 April 2016

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Abstract

Although there are many studies on biomineralization processes, most of them focus on the role of prokaryotes. As fungi play an important role in different geological and biogeochemical processes, it was considered of interest to evaluate their role in a natural extreme acidic

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Although there are many studies on biomineralization processes, most of them focus on the role of prokaryotes. As fungi play an important role in different geological and biogeochemical processes, it was considered of interest to evaluate their role in a natural extreme acidic environment, Río Tinto, which has a high level of fungal diversity and a high concentration of metals. In this work we report, for the first time, the generation of iron oxyhydroxide minerals by the fungal community in a specific location of the Tinto basin. Using Transmission Electron Microscopy (TEM) and High Angle Angular Dark Field coupled with Scanning Transmission Electron Microscopy (HAADF-STEM) and Energy-Dispersive X-ray Spectroscopy (EDX), we observed fungal structures involved in the formation of iron oxyhydroxide minerals in mineralized sediment samples from the Río Tinto basin. Although Río Tinto waters are supersaturated in these minerals, they do not precipitate due to their slow precipitation kinetics. The presence of fungi, which simply provide charged surfaces for metal binding, favors the precipitation of Fe oxyhydroxides by overcoming these kinetic barriers. These results prove that the fungal community of Río Tinto participates very actively in the geochemical processes that take place there. Full article

(This article belongs to the Special Issue Biomineralization: Towards a Unification of Concepts in Chemistry, Physics, Earth Sciences and Biology)

Open AccessArticle Iron(III) Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions

by Susana L. H. Rebelo, André M. N. Silva, Craig J. Medforth and Cristina Freire

Molecules 2016, 21(4), 481; doi:10.3390/molecules21040481

Received: 23 February 2016 / Revised: 31 March 2016 / Accepted: 5 April 2016 / Published: 12 April 2016

Abstract

Iron(III) fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H₂TPFPP) and

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Iron(III) fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H₂TPFPP) and the corresponding iron complex [Fe(TPFPP)Cl], and the use of [Fe(TPFPP)Cl] as an oxidation catalyst in green conditions. The preparations of H₂TPFPP and [Fe(TPFPP)Cl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(III)porphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide) and green solvent (ethanol). Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed. Full article

(This article belongs to the Special Issue Tetrapyrrolic Macrocycles: Synthesis, Functionalization and Applications)

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Open AccessArticle Structural Characterization of Iron Meteorites through Neutron Tomography

by Stefano Caporali, Francesco Grazzi, Filomena Salvemini, Ulf Garbe, Steven Peetermans and Giovanni Pratesi

Minerals 2016, 6(1), 14; doi:10.3390/min6010014

Received: 13 January 2016 / Revised: 10 February 2016 / Accepted: 16 February 2016 / Published: 19 February 2016

Abstract

In this communication, we demonstrate the use of neutron tomography for the structural characterization of iron meteorites. These materials prevalently consist of metallic iron with variable nickel content. Their study and classification is traditionally based on chemical and structural analysis. The latter requires

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In this communication, we demonstrate the use of neutron tomography for the structural characterization of iron meteorites. These materials prevalently consist of metallic iron with variable nickel content. Their study and classification is traditionally based on chemical and structural analysis. The latter requires cutting, polishing and chemical etching of large slabs of the sample in order to determine the average width of the largest kamacite lamellae. Although this approach is useful to infer the genetical history of these meteorites, it is not applicable to small or precious samples. On the base of different attenuation coefficient of cold neutrons for nickel and iron, neutron tomography allows the reconstruction of the Ni-rich (taenite) and Ni-poor (kamacite) metallic phases. Therefore, the measure of the average width of the largest kamacite lamellae could be determined in a non-destructive way. Furthermore, the size, shape, and spatial correlation between kamacite and taenite crystals were obtained more efficiently and accurately than via metallographic investigation. Full article

(This article belongs to the Special Issue Meteorites and Cosmic Mineralogy)

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Open AccessFeature PaperReview ROMP Synthesis of Iron-Containing Organometallic Polymers

by Ileana Dragutan, Valerian Dragutan, Petru Filip, Bogdan C. Simionescu and Albert Demonceau

Molecules 2016, 21(2), 198; doi:10.3390/molecules21020198

Received: 28 December 2015 / Accepted: 2 February 2016 / Published: 6 February 2016

Cited by 8 | Viewed by 1004 | PDF Full-text (3394 KB) | HTML Full-text | XML Full-text

Abstract

The paper overviews iron-containing polymers prepared by controlled “living” ring-opening metathesis polymerization (ROMP). Developments in the design and synthesis of this class of organometallic polymers are highlighted, pinpointing methodologies and newest trends in advanced applications of hybrid materials based on polymers functionalized with

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The paper overviews iron-containing polymers prepared by controlled “living” ring-opening metathesis polymerization (ROMP). Developments in the design and synthesis of this class of organometallic polymers are highlighted, pinpointing methodologies and newest trends in advanced applications of hybrid materials based on polymers functionalized with iron motifs. Full article

(This article belongs to the Special Issue Olefin Metathesis)

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Open AccessArticle Short- and Long-Term Effects of Prenatal Exposure to Iron Oxide Nanoparticles: Influence of Surface Charge and Dose on Developmental and Reproductive Toxicity

by Kristin R. Di Bona, Yaolin Xu, Marquita Gray, Douglas Fair, Hunter Hayles, Luckie Milad, Alex Montes, Jennifer Sherwood, Yuping Bao and Jane F. Rasco

Int. J. Mol. Sci. 2015, 16(12), 30251-30268; doi:10.3390/ijms161226231

Received: 31 July 2015 / Revised: 27 October 2015 / Accepted: 10 December 2015 / Published: 18 December 2015

Cited by 6 | Viewed by 1029 | PDF Full-text (6164 KB) | HTML Full-text | XML Full-text

Abstract

Iron oxide nanoparticles (NPs) are commonly utilized for biomedical, industrial, and commercial applications due to their unique properties and potential biocompatibility. However, little is known about how exposure to iron oxide NPs may affect susceptible populations such as pregnant women and developing fetuses.

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Iron oxide nanoparticles (NPs) are commonly utilized for biomedical, industrial, and commercial applications due to their unique properties and potential biocompatibility. However, little is known about how exposure to iron oxide NPs may affect susceptible populations such as pregnant women and developing fetuses. To examine the influence of NP surface-charge and dose on the developmental toxicity of iron oxide NPs, Crl:CD1(ICR) (CD-1) mice were exposed to a single, low (10 mg/kg) or high (100 mg/kg) dose of positively-charged polyethyleneimine-Fe₂O₃-NPs (PEI-NPs), or negatively-charged poly(acrylic acid)-Fe₂O₃-NPs (PAA-NPs) during critical windows of organogenesis (gestation day (GD) 8, 9, or 10). A low dose of NPs, regardless of charge, did not induce toxicity. However, a high exposure led to charge-dependent fetal loss as well as morphological alterations of the uteri (both charges) and testes (positive only) of surviving offspring. Positively-charged PEI-NPs given later in organogenesis resulted in a combination of short-term fetal loss (42%) and long-term alterations in reproduction, including increased fetal loss for second generation matings (mice exposed in utero). Alternatively, negatively-charged PAA-NPs induced fetal loss (22%) earlier in organogenesis to a lesser degree than PEI-NPs with only mild alterations in offspring uterine histology observed in the long-term. Full article

(This article belongs to the Special Issue Developmental and Reproductive Toxicity of Iron Oxide Nanoparticles)

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Open AccessConcept Paper Technologies for Decentralized Fluoride Removal: Testing Metallic Iron-based Filters

by Arnaud Igor Ndé-Tchoupé, Richard A. Crane, Hezron T. Mwakabona, Chicgoua Noubactep and Karoli N. Njau

Water 2015, 7(12), 6750-6774; doi:10.3390/w7126657

Received: 22 September 2015 / Revised: 11 November 2015 / Accepted: 19 November 2015 / Published: 30 November 2015

Cited by 8 | Viewed by 1203 | PDF Full-text (1343 KB) | HTML Full-text | XML Full-text

Abstract

Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media

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Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe⁰) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe⁰ is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe⁰ could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe⁰ filters for fluoride removal. The work concludes that Fe⁰-bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials. Full article

Open AccessArticle T₁-MRI Fluorescent Iron Oxide Nanoparticles by Microwave Assisted Synthesis

by Riju Bhavesh, Ana V. Lechuga-Vieco, Jesús Ruiz-Cabello and Fernando Herranz

Nanomaterials 2015, 5(4), 1880-1890; doi:10.3390/nano5041880

Received: 7 October 2015 / Revised: 26 October 2015 / Accepted: 28 October 2015 / Published: 4 November 2015

Abstract

Iron oxide nanoparticles have long been studied as a T₂ contrast agent in MRI due to their superparamagnetic behavior. T₁-based positive contrast, being much more favorable for clinical application due to brighter and more accurate signaling is, however, still limited

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Iron oxide nanoparticles have long been studied as a T₂ contrast agent in MRI due to their superparamagnetic behavior. T₁-based positive contrast, being much more favorable for clinical application due to brighter and more accurate signaling is, however, still limited to gadolinium- or manganese-based imaging tools. Though being the only available commercial positive-contrast agents, they lack an efficient argument when it comes to biological toxicity and their circulatory half-life in blood. The need arises to design a biocompatible contrast agent with a scope for easy surface functionalization for long circulation in blood and/or targeted imaging. We hereby propose an extremely fast microwave synthesis for fluorescein-labeled extremely-small iron oxide nanoparticles (fdIONP), in a single step, as a viable tool for cell labeling and T₁-MRI. We demonstrate the capabilities of such an approach through high-quality magnetic resonance angiographic images of mice. Full article

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Open AccessArticle The Effect of Plant Proteins Derived from Cereals and Legumes on Heme Iron Absorption

by Valerie Weinborn, Fernando Pizarro, Manuel Olivares, Alex Brito, Miguel Arredondo, Sebastián Flores and Carolina Valenzuela

Nutrients 2015, 7(11), 8977-8986; doi:10.3390/nu7115446

Received: 5 August 2015 / Revised: 13 October 2015 / Accepted: 22 October 2015 / Published: 30 October 2015

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Abstract

The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study).

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The aim of this study is to determine the effect of proteins from cereals and legumes on heme iron (Fe) absorption. The absorption of heme Fe without its native globin was measured. Thirty adult females participated in two experimental studies (15 per study). Study I focused on the effects of cereal proteins (zein, gliadin and glutelin) and study II on the effects of legume proteins (soy, pea and lentil) on heme Fe absorption. When heme was given alone (as a control), study I and II yielded 6.2% and 11.0% heme absorption (p > 0.05). In study I, heme Fe absorption was 7.2%, 7.5% and 5.9% when zein, gliadin and glutelin were added, respectively. From this, it was concluded that cereal proteins did not affect heme Fe absorption. In study II, heme Fe absorption was 7.3%, 8.1% and 9.1% with the addition of soy, pea and lentil proteins, respectively. Only soy proteins decreased heme Fe absorption (p < 0.05). These results suggest that with the exception of soy proteins, which decreased absorption, proteins derived from cereals and legumes do not affect heme Fe absorption. Full article

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Open AccessArticle Developmental and Reproductive Effects of Iron Oxide Nanoparticles in Arabidopsis thaliana

by Sergey Bombin, Mitchell LeFebvre, Jennifer Sherwood, Yaolin Xu, Yuping Bao and Katrina M. Ramonell

Int. J. Mol. Sci. 2015, 16(10), 24174-24193; doi:10.3390/ijms161024174

Received: 24 July 2015 / Revised: 28 September 2015 / Accepted: 7 October 2015 / Published: 13 October 2015

Cited by 3 | Viewed by 1144 | PDF Full-text (1998 KB) | HTML Full-text | XML Full-text

Abstract

Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here,

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Increasing use of iron oxide nanoparticles in medicine and environmental remediation has led to concerns regarding exposure of these nanoparticles to the public. However, limited studies are available to evaluate their effects on the environment, in particular on plants and food crops. Here, we investigated the effects of positive (PC) and negative (NC) charged iron oxide (Fe₂O₃) nanoparticles (IONPs) on the physiology and reproductive capacity of Arabidopsis thaliana at concentrations of 3 and 25 mg/L. The 3 mg/L treated plants did not show evident effects on seeding and root length. However, the 25 mg/L treatment resulted in reduced seedling (positive-20% and negative-3.6%) and root (positive-48% and negative-negligible) length. Interestingly, treatment with polyethylenimine (PEI; IONP-PC coating) also resulted in reduced root length (39%) but no change was observed with polyacrylic acid (PAA; IONP-NC coating) treatment alone. However, treatment with IONPs at 3 mg/L did lead to an almost 5% increase in aborted pollen, a 2%–6% reduction in pollen viability and up to an 11% reduction in seed yield depending on the number of treatments. Interestingly, the treated plants did not show any observable phenotypic changes in overall size or general plant structure, indicating that environmental nanoparticle contamination could go dangerously unnoticed. Full article

(This article belongs to the Special Issue Developmental and Reproductive Toxicity of Iron Oxide Nanoparticles)

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Open AccessReview Mutagenic Effects of Iron Oxide Nanoparticles on Biological Cells

by Niluka M. Dissanayake, Kelley M. Current and Sherine O. Obare

Int. J. Mol. Sci. 2015, 16(10), 23482-23516; doi:10.3390/ijms161023482

Received: 8 August 2015 / Revised: 14 September 2015 / Accepted: 18 September 2015 / Published: 30 September 2015

Cited by 7 | Viewed by 1115 | PDF Full-text (1693 KB) | HTML Full-text | XML Full-text

Abstract

In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well

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In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the OPEN ACCESS Int. J. Mol. Sci. 2015, 16 23483 transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells. Full article

(This article belongs to the Special Issue Developmental and Reproductive Toxicity of Iron Oxide Nanoparticles)

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Open AccessArticle Iron Oxide Nanoparticles Coated with a Phosphorothioate Oligonucleotide and a Cationic Peptide: Exploring Four Different Ways of Surface Functionalization

by Frédéric Geinguenaud, Claire Banissi, Antoine F. Carpentier and Laurence Motte

Nanomaterials 2015, 5(4), 1588-1609; doi:10.3390/nano5041588

Received: 18 August 2015 / Revised: 22 September 2015 / Accepted: 23 September 2015 / Published: 29 September 2015

Abstract

The superparamagnetic iron oxide nanoparticles (SPIONs) have great potential in therapeutic and diagnostic applications. Due to their superparamagnetic behavior, they are used clinically as a Magnetic Resonance Imaging (MRI) contrast agent. Iron oxide nanoparticles are also recognized todays as smart drug-delivery systems. However,

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The superparamagnetic iron oxide nanoparticles (SPIONs) have great potential in therapeutic and diagnostic applications. Due to their superparamagnetic behavior, they are used clinically as a Magnetic Resonance Imaging (MRI) contrast agent. Iron oxide nanoparticles are also recognized todays as smart drug-delivery systems. However, to increase their specificity, it is essential to functionalize them with a molecule that effectively targets a specific area of the body. Among the molecules that can fulfill this role, peptides are excellent candidates. Oligonucleotides are recognized as potential drugs for various diseases but suffer from poor uptake and intracellular degradation. In this work, we explore four different strategies, based on the electrostatic interactions between the different partners, to functionalize the surface of SPIONs with a phosphorothioate oligonucleotide (ODN) and a cationic peptide labeled with a fluorophore. The internalization of the nanoparticles has been evaluated in vitro on RAW 264.7 cells. Among these strategies, the “«one-step assembly»”, i.e., the direct complexation of oligonucleotides and peptides on iron oxide nanoparticles, provides the best way of coating for the internalization of the nanocomplexes. Full article

(This article belongs to the Special Issue Nanoparticles in Theranostics)

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Open AccessArticle Use of Nanoscale Zero-Valent Iron (NZVI) Particles for Chemical Denitrification under Different Operating Conditions

by Alessio Siciliano

Metals 2015, 5(3), 1507-1519; doi:10.3390/met5031507

Received: 9 July 2015 / Revised: 7 August 2015 / Accepted: 18 August 2015 / Published: 21 August 2015

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Abstract

The nitrate pollution of waters and groundwaters is an important environmental and health concern. An interesting method to remove the oxidized forms of nitrogen from waters and wastewaters is chemical denitrification by means of metallic iron (Fe⁰). Particularly advantageous is the

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The nitrate pollution of waters and groundwaters is an important environmental and health concern. An interesting method to remove the oxidized forms of nitrogen from waters and wastewaters is chemical denitrification by means of metallic iron (Fe⁰). Particularly advantageous is the use of nanoscopic zero-valent iron particles due to the elevated surface area, which allows reaching extremely high reaction rates. In the present paper, the efficiency of nitrate reduction by means of nanoscopic Fe⁰ has been investigated under several operating conditions. The iron nanoparticles were synthesized by the chemical reduction of ferric ions with sodium borohydride. The effects of Fe⁰ dosage, initial N–NO₃⁻ concentration and pH on chemical denitrification were identified. In particular, the results of the tests carried out showed that it is possible to reach an almost complete nitrate reduction in treating solutions with a nitrate nitrogen concentration higher than 50 mg/L. Moreover, the process performance was satisfactory also under uncontrolled pH. By means of the trends detected during the experiments, the kinetic-type reaction was identified. Furthermore, a relation between the kinetic constant and the process parameters was defined. Full article

(This article belongs to the Special Issue Hydrometallurgy)

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Open AccessArticle Engineering of Iron-Based Magnetic Activated Carbon Fabrics for Environmental Remediation

by Hai Haham, Judith Grinblat, Moulay-Tahar Sougrati, Lorenzo Stievano and Shlomo Margel

Materials 2015, 8(7), 4593-4607; doi:10.3390/ma8074593

Received: 4 June 2015 / Revised: 30 June 2015 / Accepted: 10 July 2015 / Published: 22 July 2015

Cited by 4 | Viewed by 977 | PDF Full-text (2285 KB) | HTML Full-text | XML Full-text

Abstract

Magnetic Fe₃O₄, Fe and Fe/Pd nanoparticles embedded within the pores of activated carbon fabrics (ACF) were prepared by impregnation of the ACF in iron acetylacetanoate (Fe(acac)₃) ethanol solution, followed by thermal decomposition of the embedded iron precursor

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Magnetic Fe₃O₄, Fe and Fe/Pd nanoparticles embedded within the pores of activated carbon fabrics (ACF) were prepared by impregnation of the ACF in iron acetylacetanoate (Fe(acac)₃) ethanol solution, followed by thermal decomposition of the embedded iron precursor at 200, 400 and 600 °C in an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area, pore volume, and magnetic properties of the various functionalized ACF was elucidated. The Fe nanoparticles within the ACF were also doped with tinier Pd nanoparticles, by impregnation of the Fe/ACF in palladium acetate ethanol solution. The potential use of the functionalized ACF for removal of a model azo-dye, orange II, was demonstrated. This study illustrated the enhanced removal of the dye from an aqueous solution according to the following order: Fe/Pd/ACF > Fe/ACF > ACF. In addition, the enhanced activity of Fe₃O₄/ACF in the presence of increasing concentrations of H₂O₂ (Fenton catalysts) was also illustrated. Full article

(This article belongs to the Section Structure Analysis and Characterization)

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Open AccessArticle Corrosion Inhibition of Cast Iron in Arabian Gulf Seawater by Two Different Ionic Liquids

by El-Sayed M. Sherif, Hany S. Abdo and Sherif Zein El Abedin

Materials 2015, 8(7), 3883-3895; doi:10.3390/ma8073883

Received: 13 May 2015 / Revised: 8 June 2015 / Accepted: 12 June 2015 / Published: 26 June 2015

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Abstract

In this paper we report on the corrosion inhibition of cast iron in Arabian Gulf seawater by two different ionic liquids namely, 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-butyl-1-methylpyrrolidinium chloride ([Py_1,4]Cl). The inhibiting influence of the employed ionic liquids was investigated by weight

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In this paper we report on the corrosion inhibition of cast iron in Arabian Gulf seawater by two different ionic liquids namely, 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-butyl-1-methylpyrrolidinium chloride ([Py_1,4]Cl). The inhibiting influence of the employed ionic liquids was investigated by weight loss, open circuit potential electrochemical impedance spectroscopy, and cyclic potentiodynamic polarization. The results show the corrosion inhibition impact of the employed ionic liquids (ILs). Compared with [Py_1,4]Cl, [EMIm]Cl shows a higher inhibition efficiency at a short immersion time, for the examined ILs concentrations. However, [Py_1,4]Cl exhibits a higher efficiency upon increasing the immersion time indicating the persistence of the inhibiting influence. The corrosion inhibition of the employed ionic liquids is attributed to the adsorption of the cations of the ionic liquids onto the surface of cast iron forming a corrosion barrier. Full article

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Open AccessArticle Different Storage Conditions Influence Biocompatibility and Physicochemical Properties of Iron Oxide Nanoparticles

by Jan Zaloga, Christina Janko, Rohit Agarwal, Johannes Nowak, Robert Müller, Aldo R. Boccaccini, Geoffrey Lee, Stefan Odenbach, Stefan Lyer and Christoph Alexiou

Int. J. Mol. Sci. 2015, 16(5), 9368-9384; doi:10.3390/ijms16059368

Received: 26 March 2015 / Revised: 14 April 2015 / Accepted: 15 April 2015 / Published: 24 April 2015

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Abstract

Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted increasing attention in many biomedical fields. In magnetic drug targeting SPIONs are injected into a tumour supplying artery and accumulated inside the tumour with a magnet. The effectiveness of this therapy is thus dependent on magnetic

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Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted increasing attention in many biomedical fields. In magnetic drug targeting SPIONs are injected into a tumour supplying artery and accumulated inside the tumour with a magnet. The effectiveness of this therapy is thus dependent on magnetic properties, stability and biocompatibility of the particles. A good knowledge of the effect of storage conditions on those parameters is of utmost importance for the translation of the therapy concept into the clinic and for reproducibility in preclinical studies. Here, core shell SPIONs with a hybrid coating consisting of lauric acid and albumin were stored at different temperatures from 4 to 45 °C over twelve weeks and periodically tested for their physicochemical properties over time. Surprisingly, even at the highest storage temperature we did not observe denaturation of the protein or colloidal instability. However, the saturation magnetisation decreased by maximally 28.8% with clear correlation to time and storage temperature. Furthermore, the biocompatibility was clearly affected, as cellular uptake of the SPIONs into human T-lymphoma cells was crucially dependent on the storage conditions. Taken together, the results show that the particle properties undergo significant changes over time depending on the way they are stored. Full article

(This article belongs to the Special Issue Magnetic Nanoparticles 2015)

Open AccessArticle Downhole Upgrading of Orinoco Basin Extra-Heavy Crude Oil Using Hydrogen Donors under Steam Injection Conditions. Effect of the Presence of Iron Nanocatalysts

by Cesar Ovalles, Victor Rivero and Arelys Salazar

Catalysts 2015, 5(1), 286-297; doi:10.3390/catal5010286

Received: 6 December 2014 / Revised: 25 February 2015 / Accepted: 26 February 2015 / Published: 5 March 2015

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Abstract

An extra-heavy crude oil underground upgrading concept and laboratory experiments are presented which involve the addition of a hydrogen donor (tetralin) to an Orinoco Basin extra-heavy crude oil under steam injection conditions (280–315 °C and residence times of at least 24-h). Three iron-containing

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An extra-heavy crude oil underground upgrading concept and laboratory experiments are presented which involve the addition of a hydrogen donor (tetralin) to an Orinoco Basin extra-heavy crude oil under steam injection conditions (280–315 °C and residence times of at least 24-h). Three iron-containing nanocatalysts (20 nm, 60 nm and 90 nm) were used and the results showed increases of up to 8° in API gravity, 26% desulfurization and 27% reduction in the asphaltene content of the upgraded product in comparison to the control reaction using inert sand. The iron nanocatalysts were characterized by SEM, XPS, EDAX, and Mössbauer spectroscopy before and after the upgrading reactions. The results indicated the presence of hematite (Fe₂O₃) as the predominant iron phase. The data showed that the catalysts were deactivating by particle sintering (~20% increase in particle size) and also by carbon deposition. Probable mechanisms of reactions are proposed. Full article

(This article belongs to the Special Issue Upgrading Tar Sands and Heavy Crude)

Open AccessReview Homocysteine, Iron and Cardiovascular Disease: A Hypothesis

by Joseph E. Baggott and Tsunenobu Tamura

Nutrients 2015, 7(2), 1108-1118; doi:10.3390/nu7021108

Received: 23 October 2014 / Accepted: 27 January 2015 / Published: 6 February 2015

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Abstract

Elevated circulating total homocysteine (tHcy) concentrations (hyperhomocysteinemia) have been regarded as an independent risk factor for cardiovascular disease (CVD). However, several large clinical trials to correct hyperhomocysteinemia using B-vitamin supplements (particularly folic acid) have largely failed to reduce the risk of CVD. There

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Elevated circulating total homocysteine (tHcy) concentrations (hyperhomocysteinemia) have been regarded as an independent risk factor for cardiovascular disease (CVD). However, several large clinical trials to correct hyperhomocysteinemia using B-vitamin supplements (particularly folic acid) have largely failed to reduce the risk of CVD. There is no doubt that a large segment of patients with CVD have hyperhomocysteinemia; therefore, it is reasonable to postulate that circulating tHcy concentrations are in part a surrogate marker for another, yet-to-be-identified risk factor(s) for CVD. We found that iron catalyzes the formation of Hcy from methionine, S-adenosylhomocysteine and cystathionine. Based on these findings, we propose that an elevated amount of non-protein-bound iron (free Fe) increases circulating tHcy. Free Fe catalyzes the formation of oxygen free radicals, and oxidized low-density lipoprotein is a well-established risk factor for vascular damage. In this review, we discuss our findings on iron-catalyzed formation of Hcy from thioethers as well as recent findings by other investigators on this issue. Collectively, these support our hypothesis that circulating tHcy is in part a surrogate marker for free Fe, which is one of the independent risk factors for CVD. Full article

Open AccessArticle Effects of Silicon on Mechanical Properties and Fracture Toughness of Heavy-Section Ductile Cast Iron

by Liang Song, Erjun Guo, Liping Wang and Dongrong Liu

Metals 2015, 5(1), 150-161; doi:10.3390/met5010150

Received: 3 December 2014 / Accepted: 8 January 2015 / Published: 21 January 2015

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Abstract

The effects of silicon (Si) on the mechanical properties and fracture toughness of heavy-section ductile cast iron were investigated to develop material for spent-nuclear-fuel containers. Two castings with different Si contents of 1.78 wt.% and 2.74 wt.% were prepared. Four positions in the

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The effects of silicon (Si) on the mechanical properties and fracture toughness of heavy-section ductile cast iron were investigated to develop material for spent-nuclear-fuel containers. Two castings with different Si contents of 1.78 wt.% and 2.74 wt.% were prepared. Four positions in the castings from the edge to the center, with different solidification cooling rates, were chosen for microstructure observation and mechanical properties’ testing. Results show that the tensile strength, elongation, impact toughness and fracture toughness at different positions of the two castings decrease with the decrease in cooling rate. With an increase in Si content, the graphite morphology and the mechanical properties at the same position deteriorate. Decreasing cooling rate changes the impact fracture morphology from a mixed ductile-brittle fracture to a brittle fracture. The fracture morphology of fracture toughness is changed from ductile to brittle fracture. When the Si content exceeds 1.78 wt.%, the impact and fracture toughness fracture morphology transforms from ductile to brittle fracture. The in-situ scanning electronic microscope (SEM) tensile experiments were first used to observe the dynamic tensile process. The influence of the vermicular and temper graphite on fracture formation of heavy section ductile iron was investigated. Full article

(This article belongs to the Special Issue Advances in Solidification Processing)

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Open AccessArticle Micronutrient Status in Female University Students: Iron, Zinc, Copper, Selenium, Vitamin B₁₂ and Folate

by Flavia Fayet-Moore, Peter Petocz and Samir Samman

Nutrients 2014, 6(11), 5103-5116; doi:10.3390/nu6115103

Received: 17 August 2014 / Revised: 24 October 2014 / Accepted: 28 October 2014 / Published: 13 November 2014

Cited by 8 | Viewed by 2535 | PDF Full-text (153 KB) | HTML Full-text | XML Full-text

Abstract

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students

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Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18–35 year; Body Mass Index 21.5 ± 2.8 kg/m²; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B₁₂, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B₁₂ concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 μmol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 μmol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B₁₂, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation. Full article

Open AccessReview Iron, Magnesium, Vitamin D, and Zinc Deficiencies in Children Presenting with Symptoms of Attention-Deficit/Hyperactivity Disorder

by Amelia Villagomez and Ujjwal Ramtekkar

Children 2014, 1(3), 261-279; doi:10.3390/children1030261

Received: 31 May 2014 / Revised: 12 August 2014 / Accepted: 21 August 2014 / Published: 29 September 2014

Cited by 3 | Viewed by 2235 | PDF Full-text (256 KB) | HTML Full-text | XML Full-text

Abstract

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder increasing in prevalence. Although there is limited evidence to support treating ADHD with mineral/vitamin supplements, research does exist showing that patients with ADHD may have reduced levels of vitamin D, zinc, ferritin, and magnesium. These nutrients

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Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder increasing in prevalence. Although there is limited evidence to support treating ADHD with mineral/vitamin supplements, research does exist showing that patients with ADHD may have reduced levels of vitamin D, zinc, ferritin, and magnesium. These nutrients have important roles in neurologic function, including involvement in neurotransmitter synthesis. The aim of this paper is to discuss the role of each of these nutrients in the brain, the possible altered levels of these nutrients in patients with ADHD, possible reasons for a differential level in children with ADHD, and safety and effect of supplementation. With this knowledge, clinicians may choose in certain patients at high risk of deficiency, to screen for possible deficiencies of magnesium, vitamin D, zinc, and iron by checking RBC-magnesium, 25-OH vitamin D, serum/plasma zinc, and ferritin. Although children with ADHD may be more likely to have lower levels of vitamin D, zinc, magnesium, and iron, it cannot be stated that these lower levels caused ADHD. However, supplementing areas of deficiency may be a safe and justified intervention. Full article

(This article belongs to the Special Issue Pediatric Integrative Medicine: An Emerging Field of Pediatrics) Printed Edition available

Open AccessArticle Interactive Effects of Dietary Fat/Carbohydrate Ratio and Body Mass Index on Iron Deficiency Anemia among Taiwanese Women

by Jung-Su Chang, Yi-Chun Chen, Eddy Owaga, Khairizka Citra Palupi, Wen-Harn Pan and Chyi-Huey Bai

Nutrients 2014, 6(9), 3929-3941; doi:10.3390/nu6093929

Received: 4 July 2014 / Revised: 25 August 2014 / Accepted: 1 September 2014 / Published: 24 September 2014

Cited by 5 | Viewed by 2096 | PDF Full-text (381 KB) | HTML Full-text | XML Full-text

Abstract

Whether being overweight or obese is associated with increased risk of iron deficiency anemia (IDA) remains controversial. We evaluated the dietary intakes and risk for IDA in relation to body mass index (BMI). One thousand two hundred and seventy-four females aged ≥19 years,

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Whether being overweight or obese is associated with increased risk of iron deficiency anemia (IDA) remains controversial. We evaluated the dietary intakes and risk for IDA in relation to body mass index (BMI). One thousand two hundred and seventy-four females aged ≥19 years, enrolled in the third Nutrition and Health Survey in Taiwan (NAHSIT) 2005–2008, were selected. Half of the women were either overweight (24.0%) or obese (25.3%). The overall prevalence of anemia, iron deficiency and IDA among adult women was 19.5%, 8.6% and 6.2%. BMI showed a protective effect on IDA: overweight (odds ratio, OR: 0.365 (0.181–0.736)) and obese (OR: 0.480 (0.259–0.891)) when compared with normal weight. Univariate analysis identified increased IDA risk for overweight/obese women who consumed higher dietary fat but lower carbohydrate (CHO) (OR: 10.119 (1.267–80.79)). No such relationship was found in IDA women with normal weight (OR: 0.375 (0.036–4.022)). Analysis of interaction(s) showed individuals within the highest BMI tertile (T3) had the lowest risk for IDA and the risk increased with increasing tertile groups of fat/CHO ratio; OR 0.381 (0.144–1.008; p = 0.051), 0.370 (0.133–1.026; p = 0.056) and 0.748 (0.314–1.783; p = 0.513); for T1, T2 and T3, respectively. In conclusion, a protective effect of BMI on IDA may be attenuated in women who had increased fat/CHO ratio. Full article

(This article belongs to the Special Issue Iron Deficiency: Development, Implications and Treatment)

Open AccessArticle A Sustainable Approach for the Geopolymerization of Natural Iron-Rich Aluminosilicate Materials

by Esther A. Obonyo, Elie Kamseu, Patrick N. Lemougna, Arlin B. Tchamba, Uphie C. Melo and Cristina Leonelli

Sustainability 2014, 6(9), 5535-5553; doi:10.3390/su6095535

Received: 7 July 2014 / Revised: 14 August 2014 / Accepted: 15 August 2014 / Published: 25 August 2014

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Abstract

Two iron-rich clayey materials (L1 and L2, with the main difference being the level of iron accumulation) have been studied for their suitability as solid precursors for inorganic polymer composites. L1, with the lower iron content, was calcined at 700°C for 4 h

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Two iron-rich clayey materials (L1 and L2, with the main difference being the level of iron accumulation) have been studied for their suitability as solid precursors for inorganic polymer composites. L1, with the lower iron content, was calcined at 700°C for 4 h and used as replacement, in the range of 15–35 wt%, for both raw laterites in the formulations of geopolymeric composites. The different mixtures were activated with a highly concentrated alkaline solution containing sodium hydroxide and sodium silicate. River sand with semi-crystalline structure was added to form semi-dry pastes which were pressed to appropriate shape. X-ray diffraction, Infrared spectroscopy, Scanning Electron Microscopy and Mercury Intrusion Porosimetry results demonstrated the effectiveness of the calcined fraction of L1 to act as nucleation sites and extend the geopolymerization to the matrix composites. A highly compact matrix with low porosity and good stability in water, together with a strength comparable to that of standard concretes was obtained allowing for conclusions to be made on the quality of laterites as promising solid precursor for sustainable, environmentally-friendly, and cost-efficient structural materials. Full article

(This article belongs to the Special Issue Sustainability of Resources)

Open AccessReview Application of Iron Magnetic Nanoparticles in Protein Immobilization

by Jiakun Xu, Jingjing Sun, Yuejun Wang, Jun Sheng, Fang Wang and Mi Sun

Molecules 2014, 19(8), 11465-11486; doi:10.3390/molecules190811465

Received: 23 May 2014 / Revised: 9 July 2014 / Accepted: 9 July 2014 / Published: 4 August 2014

Cited by 42 | Viewed by 2201 | PDF Full-text (1045 KB) | HTML Full-text | XML Full-text

Abstract

Due to their properties such as superparamagnetism, high surface area, large surface-to-volume ratio, easy separation under external magnetic fields, iron magnetic nanoparticles have attracted much attention in the past few decades. Various modification methods have been developed to produce biocompatible magnetic nanoparticles for

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Due to their properties such as superparamagnetism, high surface area, large surface-to-volume ratio, easy separation under external magnetic fields, iron magnetic nanoparticles have attracted much attention in the past few decades. Various modification methods have been developed to produce biocompatible magnetic nanoparticles for protein immobilization. This review provides an updated and integrated focus on the fabrication and characterization of suitable magnetic iron nanoparticle-based nano-active materials for protein immobilization. Full article

(This article belongs to the Special Issue Enzyme Immobilization)

Open AccessArticle Design of Magnetic Gelatine/Silica Nanocomposites by Nanoemulsification: Encapsulation versus in Situ Growth of Iron Oxide Colloids

by Joachim Allouche, Corinne Chanéac, Roberta Brayner, Michel Boissière and Thibaud Coradin

Nanomaterials 2014, 4(3), 612-627; doi:10.3390/nano4030612

Received: 18 June 2014 / Revised: 18 July 2014 / Accepted: 21 July 2014 / Published: 31 July 2014

Cited by 3 | Viewed by 2439 | PDF Full-text (1852 KB) | HTML Full-text | XML Full-text

Abstract

The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first

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The design of magnetic nanoparticles by incorporation of iron oxide colloids within gelatine/silica hybrid nanoparticles has been performed for the first time through a nanoemulsion route using the encapsulation of pre-formed magnetite nanocrystals and the in situ precipitation of ferrous/ferric ions. The first method leads to bi-continuous hybrid nanocomposites containing a limited amount of well-dispersed magnetite colloids. In contrast, the second approach allows the formation of gelatine-silica core-shell nanostructures incorporating larger amounts of agglomerated iron oxide colloids. Both magnetic nanocomposites exhibit similar superparamagnetic behaviors. Whereas nanocomposites obtained via an in situ approach show a strong tendency to aggregate in solution, the encapsulation route allows further surface modification of the magnetic nanocomposites, leading to quaternary gold/iron oxide/silica/gelatine nanoparticles. Hence, such a first-time rational combination of nano-emulsion, nanocrystallization and sol-gel chemistry allows the elaboration of multi-component functional nanomaterials. This constitutes a step forward in the design of more complex bio-nanoplatforms. Full article

(This article belongs to the Special Issue Self-Assembled Nanomaterials)

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Open AccessArticle Jarosite versus Soluble Iron-Sulfate Formation and Their Role in Acid Mine Drainage Formation at the Pan de Azúcar Mine Tailings (Zn-Pb-Ag), NW Argentina

by Jesica Murray, Alicia Kirschbaum, Bernhard Dold, Edi Mendes Guimaraes and Elisa Pannunzio Miner

Minerals 2014, 4(2), 477-502; doi:10.3390/min4020477

Received: 28 February 2014 / Revised: 12 May 2014 / Accepted: 19 May 2014 / Published: 30 May 2014

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Abstract

Secondary jarosite and water-soluble iron-sulfate minerals control the composition of acid mine waters formed by the oxidation of sulfide in tailings impoundments at the (Zn-Pb-Ag) Pan de Azúcar mine located in the Pozuelos Lagoon Basin (semi-arid climate) in Northwest (NW) Argentina. In the

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Secondary jarosite and water-soluble iron-sulfate minerals control the composition of acid mine waters formed by the oxidation of sulfide in tailings impoundments at the (Zn-Pb-Ag) Pan de Azúcar mine located in the Pozuelos Lagoon Basin (semi-arid climate) in Northwest (NW) Argentina. In the primary zone of the tailings (9.5 wt % pyrite-marcasite) precipitation of anglesite (PbSO₄), wupatkite ((Co,Mg,Ni)Al₂(SO₄)₄) and gypsum retain Pb, Co and Ca, while mainly Fe²⁺, Zn²⁺, Al³⁺, Mg²⁺, As^3+/5+ and Cd²⁺ migrate downwards, forming a sulfate and metal-rich plume. In the oxidation zone, jarosite (MFe₃(TO₄)₂(OH)₆) is the main secondary Fe³⁺ phase; its most suitable composition is M = K⁺, Na⁺, and Pb²⁺and TO₄ = SO₄²⁻; AsO₄²⁻. During the dry season, iron-sulfate salts precipitate by capillary transport on the tailings and at the foot of DC2 (tailings impoundment DC2) tailings dam where an acid, Fe²⁺ rich plume outcrops. The most abundant compounds in the acid mine drainage (AMD) are SO₄²⁻, Fe²⁺, Fe³⁺, Zn²⁺, Al³⁺, Mg²⁺, Cu²⁺, As^3+/5+, Cd²⁺. These show peak concentrations at the beginning of the wet season, when the soluble salts and jarosite dissolve. The formation of soluble sulfate salts during the dry season and dilution during the wet season conform an annual cycle of rapid metals and acidity transference from the tailings to the downstream environment. Full article

(This article belongs to the Special Issue Mine Waste Characterization, Management and Remediation)

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Open AccessArticle Synthesis, Surface Modification and Characterisation of Biocompatible Magnetic Iron Oxide Nanoparticles for Biomedical Applications

by Mahnaz Mahdavi, Mansor Bin Ahmad, Md Jelas Haron, Farideh Namvar, Behzad Nadi, Mohamad Zaki Ab Rahman and Jamileh Amin

Molecules 2013, 18(7), 7533-7548; doi:10.3390/molecules18077533

Received: 24 April 2013 / Revised: 10 June 2013 / Accepted: 25 June 2013 / Published: 27 June 2013

Cited by 137 | Viewed by 4204 | PDF Full-text (1535 KB) | HTML Full-text | XML Full-text

Abstract

Superparamagnetic iron oxide nanoparticles (MNPs) with appropriate surface chemistry exhibit many interesting properties that can be exploited in a variety of biomedical applications such as magnetic resonance imaging contrast enhancement, tissue repair, hyperthermia, drug delivery and in cell separation. These applications required that

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Superparamagnetic iron oxide nanoparticles (MNPs) with appropriate surface chemistry exhibit many interesting properties that can be exploited in a variety of biomedical applications such as magnetic resonance imaging contrast enhancement, tissue repair, hyperthermia, drug delivery and in cell separation. These applications required that the MNPs such as iron oxide Fe₃O₄ magnetic nanoparticles (Fe₃O₄ MNPs) having high magnetization values and particle size smaller than 100 nm. This paper reports the experimental detail for preparation of monodisperse oleic acid (OA)-coated Fe₃O₄ MNPs by chemical co-precipitation method to determine the optimum pH, initial temperature and stirring speed in order to obtain the MNPs with small particle size and size distribution that is needed for biomedical applications. The obtained nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence spectrometry (EDXRF), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). The results show that the particle size as well as the magnetization of the MNPs was very much dependent on pH, initial temperature of Fe²⁺ and Fe³⁺ solutions and steering speed. The monodisperse Fe₃O₄ MNPs coated with oleic acid with size of 7.8 ± 1.9 nm were successfully prepared at optimum pH 11, initial temperature of 45 °C and at stirring rate of 800 rpm. FTIR and XRD data reveal that the oleic acid molecules were adsorbed on the magnetic nanoparticles by chemisorption. Analyses of TEM show the oleic acid provided the Fe₃O₄ particles with better dispersibility. The synthesized Fe₃O₄ nanoparticles exhibited superparamagnetic behavior and the saturation magnetization of the Fe₃O₄ nanoparticles increased with the particle size. Full article

Open AccessArticle Oxidative Debromination and Degradation of Tetrabromo-bisphenol A by a Functionalized Silica-Supported Iron(III)-tetrakis(p-sulfonatophenyl)porphyrin Catalyst

by Qianqian Zhu, Yusuke Mizutani, Shohei Maeno and Masami Fukushima

Molecules 2013, 18(5), 5360-5372; doi:10.3390/molecules18055360

Received: 15 April 2013 / Revised: 7 May 2013 / Accepted: 7 May 2013 / Published: 10 May 2013

Cited by 15 | Viewed by 2127 | PDF Full-text (398 KB) | HTML Full-text | XML Full-text

Abstract

Tetrabromobisphenol A (TBBPA), a commonly used brominated flame retardant, also functions as an endocrine disruptor. Thus, the degradation of TBBPA has attracted considerable interest among the scientific community. Iron(III)-porphyrin complexes are generally regarded as “green” catalysts and have been reported to catalyze the

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Tetrabromobisphenol A (TBBPA), a commonly used brominated flame retardant, also functions as an endocrine disruptor. Thus, the degradation of TBBPA has attracted considerable interest among the scientific community. Iron(III)-porphyrin complexes are generally regarded as “green” catalysts and have been reported to catalyze the efficient degradation and dehalogenation of halogenated phenols in environmental wastewaters. However, they are quickly deactivated due to self-degradation in the presence of an oxygen donor, such as KHSO₅. In the present study, an iron(III)-tetrakis (p-sulfonatophenyl)-porphyrin (FeTPPS) was immobilized on imidazole-modified silica (FeTPPS/IPS) via coordination of the Fe(III) with the nitrogen atom in imidazole to suppress self-degradation and thus enhance the catalyst reusability. The oxidative degradation and debromination of TBBPA and the influence of humic acid (HA), a major component in leachates, on the oxidation of TBBPA was investigated. More than 95% of the TBBPA was degraded in the pH range from 3 to 8 in the absence of HA, while the optimal pH for the reaction was at pH 8 in the presence of HA. Although the rate of degradation was decreased in the presence of HA, over 95% of the TBBPA was degraded within 12 h in the presence of 28 mg-C L⁻¹ of HA. At pH 8, the FeTPPS/IPS catalyst could be reused up to 10 times without any detectable loss of activity for TBBPA for degradation and debromination, even in the presence of HA. Full article

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Open AccessArticle Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C

by Shinji Kudo, Taisuke Maki, Takashi Fukuda and Kazuhiro Mae

Catalysts 2011, 1(1), 175-190; doi:10.3390/catal1010175

Received: 6 October 2011 / Revised: 14 November 2011 / Accepted: 29 November 2011 / Published: 9 December 2011

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Abstract

Low-temperature water-gas shift reaction (WGS) using gold catalyst is expected to be an attractive technique to realize an efficient on-site hydrogen production process. In this paper, Au/Fe₃O₄ catalysts for promoting the WGS below 150 °C were developed by a preliminary

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Low-temperature water-gas shift reaction (WGS) using gold catalyst is expected to be an attractive technique to realize an efficient on-site hydrogen production process. In this paper, Au/Fe₃O₄ catalysts for promoting the WGS below 150 °C were developed by a preliminary reduction of Au/iron oxide (Fe³⁺) catalyst utilizing high reactivity of Au nano-particles. The reduction was conducted under a CO, H₂, or CO/H₂O stream at either 140 or 200 °C, and the effect of reduction conditions on the characteristics of the Au/Fe₃O₄ catalyst and on the catalytic activity in WGS at 80 °C was investigated. The reaction progress during the pre-reduction treatment was qualitatively analyzed, and it was found that the iron oxide in Au/Fe₂O₃ calcined at 200 °C was easily reduced to Fe₃O₄ phase in all reduction conditions. The reduction conditions affected the characteristics of both Au and iron oxide, but all of the reduced catalysts had small Fe₃O₄ particles of less than 20 nm with Au particles on the surface. The surface area and content of cationic Au were high in the order of CO, H₂, CO/H₂O, and 140, 200 °C. In the WGS test at 80 °C using the developed catalysts, the activities of the catalysts pre-reduced by CO at 140 or 200 °C and by H₂ at 140 °C were very high with 100% CO conversion even at such a low temperature. These results indicated that factors such as higher surface area, crystallized Fe₃O₄, and cationic Au content contributed to the catalytic activity. Full article

(This article belongs to the Special Issue Gold Catalysts)

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Open AccessArticle Chitosan Interaction with Iron from Yoghurt Using an In Vitro Digestive Model: Comparative Study with Plant Dietary Fibers

by Marina Dello Staffolo, Miriam Martino, Alicia Bevilacqua, Mirta Montero, María Susana Rodríguez and Liliana Albertengo

Int. J. Mol. Sci. 2011, 12(7), 4647-4660; doi:10.3390/ijms12074647

Received: 5 May 2011 / Revised: 4 June 2011 / Accepted: 8 July 2011 / Published: 19 July 2011

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Abstract

The objective of this work was to investigate the interaction of chitosan with iron from yoghurt by an in vitro gastrointestinal tract model. Taking into account that chitosan is a polysaccharide included in fiber definition by Codex Alimentarius; chitosan behavior was studied and

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The objective of this work was to investigate the interaction of chitosan with iron from yoghurt by an in vitro gastrointestinal tract model. Taking into account that chitosan is a polysaccharide included in fiber definition by Codex Alimentarius; chitosan behavior was studied and compared with different plant fiber (wheat, bamboo, apple, psyllium and inulin) behaviors, in the same in vitro conditions. Ferrous sulfate was added to yoghurts with each type of fiber. The gastric environment was simulated with HCl (pH 1.0–2.0). The duodenal environment was simulated with NaHCO₃ (pH 6.8–7.2) and a dialysis tubing cellulose membrane. Results showed that chitosan had the highest iron retention percentages (53.2% at 30 min; 56.8% at 60 min) interacting in a more pronounced manner with iron than the plant fibers used in this work. Full article

(This article belongs to the Special Issue Dietary Fibre: Biochemistry and Nutritional Science)

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Open AccessArticle Reduction of Nitroaromatic Compounds on the Surface of Metallic Iron: Quantum Chemical Study

by Igor Zilberberg, Alexander Pelmenschikov, Christian J. Mcgrath, William Davis, Danuta Leszczynska and Jerzy Leszczynski

Int. J. Mol. Sci. 2002, 3(7), 801-813; doi:10.3390/i3070801

Received: 21 August 2001 / Accepted: 17 May 2002 / Published: 31 July 2002

Cited by 12 | Viewed by 5538 | PDF Full-text (413 KB) | HTML Full-text | XML Full-text

Abstract

The initial reduction steps of nitroaromatic compounds on the surface of metallic iron have been studied theoretically using nitrobenzene (NB) as a representative of nitroaromatic compounds. The quantum chemical cluster approximation within the semiempirical Neglect of Diatomic Differential Overlap for Metal Compounds method

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The initial reduction steps of nitroaromatic compounds on the surface of metallic iron have been studied theoretically using nitrobenzene (NB) as a representative of nitroaromatic compounds. The quantum chemical cluster approximation within the semiempirical Neglect of Diatomic Differential Overlap for Metal Compounds method was applied to model the Fe(110) crystallographic surface, taken as a representative reactive surface for granular iron. This surface was modeled as a 39-atom two-layer metal cluster with rigid geometry. The associative and dissociative adsorption of nitrobenzene was considered. Based on our quantum chemical analysis, we suggest that the direct electron donation from the metal surface into the π* orbital of NB is a decisive factor responsible for subsequent transformation of the nitro group. Molecularly adsorbed NB interacts with metal iron exclusively through nitro moiety oxygens which occupy tri-coordinated positions on surface The charge transfer from metal to NB of approximately 2 atomic units destablizes the nitro group. As a result, the first dissociation of the N-O bond goes through a relatively low activation barrier. The adsorbed nitrosobenzene is predicted to be a stable surface species, though still quiet labile. Full article

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